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HIGH THEMAL ENERGY STORAGE DENSITY MOLTEN SALTS FOR PARABOLIC
TROUGH SOLAR POWER GENERATION
by
TAO WANG
RAMANA G REDDY COMMITTEE CHAIR
NITIN CHOPRA
YANG-KI HONG
A THESIS
Submitted in partial fulfillment of the requirements
for the degree of Master of Science
in the Department of Metallurgical and Materials Engineering
in the Graduate School of
The University of Alabama
TUSCALOOSA ALABAMA
2011
Copyright Tao Wang 2011
ALL RIGHTS RESERVED
ii
ABSTRACT
New alkali nitrate-nitrite systems were developed by using thermodynamic modeling and
the eutectic points were predicted based on the change of Gibbs energy of fusion Those systems
with melting point lower than 130oC were selected for further analysis The new compounds
were synthesized and the melting point and heat capacity were determined using Differential
Scanning Calorimetry (DSC) The experimentally determined melting points agree well with the
predicted results of modeling It was found that the lithium nitrate amount and heating rate have
significant effects on the melting point value and the endothermic peaks Heat capacity data as a
function of temperature are fit to polynomial equation and thermodynamic properties like
enthalpies entropies and Gibbs energies of the systems as function of temperature are
subsequently induced The densities for the selected systems were experimentally determined
and found in a very close range due to the similar composition In liquid state the density values
decrease linearly as temperature increases with small slope Moreover addition of lithium nitrate
generally decreases the density On the basis of density heat capacity and the melting point
thermal energy storage was calculated Among all the new molten salt systems LiNO3-NaNO3-
KNO3-Mg(NO3)2-MgKN quinary system presents the largest thermal energy storage density as
well as the gravimetric density values Compared to the KNO3-NaNO3 binary solar salt all the
new molten salts present larger thermal energy storage as well as the gravimetric storage density
values which indicate the better thermal energy storage capacity for solar power generation
systems
iii
DEDICATION
This thesis is dedicated to everyone who helped me and guided me through the trials and
tribulations of creating this manuscript In particular my family and close friends who stood by
me throughout the time taken to complete this masterpiece
iv
ACKNOWLEDGEMENTS
I am pleased to express my gratitude and appreciation to my advisor Professor Ramana
G Reddy for his patience and guidance during my graduate study and the entire research work I
am greatly benefited from his experience knowledge and enthusiasm for scientific research
I would like to express my sincere thanks to Dr Nitin Chopra and Dr Yang-Ki Hong for
serving on my committee Their valuable suggestions and comments are very insightful for my
research work
I would like to thank all the research colleagues of Dr Reddy‟s research group special
thanks to Dr Divakar Mantha for his valuable suggestions and comments I would like to extend
my gratitude to US Department of Energy for the financial support
Finally I would like to thank my parents and my fianceacutee whose invaluable
understanding and loving support helped me through the difficult times
v
TABLE OF CONTENTS
ABSTRACT ii
DEDICATION iii
ACKNOWLEDGEMENTS iv
LIST OF TABLES viii
LIST OF FIGURES x
CHAPTER 1 INTRODUCTION 1
CHAPTER 2 LITERATURE REVIEW 11
21 Melting point 11
22 Density 15
23 Heat capacity 18
CHAPTER 3 OBJECTIVES 22
CHAPTER 4 THERMODYNAMIC MODELING OF SALT SYSTEMS 24
41 Thermodynamic modeling 24
42 Calculations 27
vi
CHAPTER 5 EXPERIMENTAL PROCEDURE 30
51 Melting point determination of molten salt mixtures 30
511 Materials 30
512 Apparatus and Procedure 30
52 Heat Capacity determination of molten salt mixtures 32
53 Density determination of molten salt mixtures 33
CHAPTER 6 RESULT AND DISCUSSION 34
61 Melting point determination 34
611 DSC equipment calibration 34
612 Results 35
613 Discussion 41
62 Heat capacity determination 51
621 Heat capacity calibration 51
622 Results 52
623 Thermodynamic properties 55
624 Discussion of Gibbs energy change for molten salts 84
63 Density determination 86
vii
631 Density calibration 86
632 Results and discussions 82
64 Thermal energy storage density of molten salts 90
CHAPTER 7 CONCLUSION 94
REFERENCES 96
APPENDIX 104
APPENDIX A 104
APPENDIX B 109
APPENDIX C 114
APPENDIX D 118
APPENDIX E 123
APPENDIX F 128
APPENDIX G 133
APPENDIX H 138
APPENDIX I 143
viii
LIST OF TABLES
21 Melting point of various nitrate salt systems 12
22 Melting point of various carbonate salt systems 13
23 Melting point of various fluoridechloride salt systems 14
24 Melting point of various hydroixde salt systems 15
25 Density coefficients A and B of nitrate salts 16
26 Density coefficients A and B of carbonate salts 17
27 Density coefficients A and B of chloridefluoride salts 17
28 Density coefficients A and B of molten salt mixture with hydroxide salts 18
29 Heat capacity of alkali nitrate salt at 500oC 19
210 Heat capacity of alkali carbonate salt at 500oC 19
211 Heat capacity of fluoridechloride salt at 500oC 20
212 Heat capacity of hydroxide salt at 500oC 21
41 Calculated composition and melting point for multi-component systems 29
61 Calibration data of melting points with different samples 35
62 DSC results of melting point transition point and change of enthalpy 41
ix
63 Fusion and solid phase transition temperature for individual salts 42
64 Melting points of candidate systems as function of temperatures 51
65 Calibration data of heat capacities with different samples 52
66 Heat capacity of selected new TES molten salt mixtures 54
67 Change of Gibbs energy values at 62315K for molten salt systems 85
68 Calibration of density measurements with different pure nitrate salts 86
69 Coefficient of A and B for density determination of salt 1 to salt 9 87
610 Extrapolated value of density and heat capacity at 500oC of salt 1 to salt 9 91
611 Energy density of salt 1 to salt 9 compare to solar salt 92
612 Gravimetric storage densities for solar salt and new molten salts 93
x
LIST OF FIGURES
11 Theoretical and engineering energy conversion efficiency as function of temperature 6
12 Gravimetric storage density for different energy storage systems
as function of temperature 8
51 Photography of set-up for DSC equipment 31
61 Melting point calibration with indium sample 34
62 Melting point calibration with KNO3 sample 35
63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt 36
64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt 37
65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt 37
66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt 38
67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt 38
68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt 39
69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt 39
610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt 40
611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN Salt 40
612 DSC plot of 698wt KNO3 -302wt NaNO2 binary system 43
xi
613 DSC plot of 270wt NaNO3-730wt KNO3 binary system 45
614 DSC plot of 458wtLiNO3-542wtKNO3 binary system 45
615 DSC plot of 460wt NaNO3-540wt KNO3 binary system 46
616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 20oCmin heating rate 47
616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 5oCmin heating rate 48
617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 5oCmin heating rate 49
617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 20oCmin heating rate 49
618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system
as function of temperature 53
619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K 54
620 Change of Gibbs energy as function of temperature for molten salt systems 85
621 The densities of the salt 1 to salt 5 as function of temperature 87
622 The densities of the salt 6 to salt 9 as function of temperature 89
623 Densities of the salt 1 salt 2 as function of temperature compared to
the equimolar NaNO3-KNO3 binary system and pure KNO3 90
624 Gravimetric storage density comparison of different energy storage
xii
systems as function of temperature 93
1
CHAPTER 1
INTRODUCTION
Renewable energy sources such as wind solar water power geothermal and biomass are
playing more and more significant role in our energy supply Because the cheap cost and infinite
amount of energy storage inside the resource solar energy is emphasized since 20th
century and
viewed as promising alternative method to satisfy the large energy consumption every day in the
world reduce the emission of carbon and strengthen the economy
The wind energy was used as a clean energy to generate electricity back to late 19th
century
However this renewable energy source was not emphasized due to the cheap price of fossil fuel
The re-emergence happened in mid 1950s when the amount of traditional energy source was
found apparently decrease The development of wind energy usage continued and in 1990 the
first mega-watt wind turbine was launched which was viewed as a symbol of shift to large scale
wind energy utilization [1-2] The modern application of wind energy mainly relies on wind
turbine On the basis of aerodynamic wind turbine generates certain net positive torque on
rotating shaft and then converts the mechanical power to electrical power As an electrical power
generator wind turbine is connected to some electrical network to transport the electricity to
battery charging utilities residential power systems and large scale energy consuming systems
In general most of wind turbines are small scale and can only generate 10KW electrical power
Only few of the wind turbine systems operate with capacity as large as 5MW Although the
usage of wind energy can reduce the emission of carbon oxide the noise pollution and high cost
2
limit its large scale application Since the wind is not transportable the electrical energy can only
be generated where the wind blows which also decrease the flexibility of wind energy
Water power is another term of alternative power supply and it was used for irrigation
operating machines like watermill even before the development of electrical power The modern
application of water power is to generate electricity by using the gravitational force of falling or
flowing water These days there are various ways for the water power application The most
traditional method is to store the water in dam and generate electricity by converting the
potential energy pump storage is a different way to utilize water power and can change its
output depending on the energy demand by moving water between reservoirs at different
elevations In the low energy demand period excess energy is used to lift water to the higher
level while in the peak period of energy demand the water is released back to the lower
elevation through water turbine Water power can also be converted by taking advantage of
naturally raise and fall of tide to satisfy the demand of electrical energy consumption [3]
Although the usage of water power can reduce the emission of carbon dioxide and cost it will
destroy the ecosystem because of the large land required for construction There will be methane
emission from the reservoir the potential failure hazard of dam is also a fatal issue and flow
shortage caused by drought may also create serious problem As result of that water power
technique is not a long-term alternative choice
Geothermal energy is the energy form generated inside the earth At the very beginning of
the planet formation a large amount of thermal energy was stored from the radioactive decay of
minerals volcanic activity and solar energy absorption Because of the temperature difference
3
between the core and the surface of planet the thermal energy stored inside the earth is driven to
the outer surface in the form of heat This form of renewable energy source can be applied to
generate electrical power and heat for industrial space and agricultural applications
Theoretically the deposited amount of geothermal energy is adequate to supply the energy
consumption in the world However most of the geothermal energy is stored deeply near the
core of the earth the deep drilling and exploration of geothermal energy is very expensive and
limits the large-scale use of this renewable energy source [4]
Biomass is a renewable energy source used to generate heat or electricity with living or
recently living organism such as wood waste (hydrogen) gas and alcohol fuels The biomass
energy can be converted to electrical energy by thermal method such as combustion pyrolysis
and gasification Several specific chemical processes may also be able to convert the biomass
energy to other forms The main problem arise from application of biomass is air pollution which
contains carbon monoxide NOx (nitrogen oxides) VOCs (volatile organic compounds)
particulates and other pollutants And the level of air pollution to some extent is even above that
of traditional fuel resource Some other possible issue like transportation and sink of carbon also
limit the wide usage of this type of alternative energy [5]
Among all the renewable energy sources solar energy is the most suitable alternative
energy for our future life It is clean cheap abundant without any noise air pollution no
transportation issue and easy to be obtained anywhere in the earth Inside the core of the Sun
hydrogen fuses into helium with a rate of 7times1011
kgs and generates very powerful nucleation
power This type of nucleation explosion creates ultra high temperature in the core of the Sun
4
which reaches approximately 16 million K degrees Although the Sun is not perfectly black body
it still radiates abundant power with the energy density as 16times107 wattsm
2 [6-7] Because of the
enough amount of hydrogen underneath the surface of the Sun the radiation given arise of from
the nucleation explosion can continue at least 5 million years with the same rate and strength
The energy reaching the earth is vastly reduced mainly caused by the absorption and spreading
of the radiation It is easily to understand that there are numerous amorphous objects all around
the entire universe which can absorb certain portion of the radiation for the Sun Moreover the
light generated from the spherical object such as the Sun fills all the available space between the
origin to the destination Even though the energy will not be lost in the travelling process due to
the long distance between the Sun to the earth the surface area of the sphere which is formed
with the Sun as center and the distance as radius is much larger than that of the earth As the
result of that only 1340Wm2 finally reaches the upmost surface of the earth Even though the
final amount of the received solar energy is very small compared to that is initially radiated from
the Sun the average daily solar radiation falling on one area in the continental United States is
equivalent in total energy content to 11 barrels of oil In summary the solar energy itself is
relatively unlimited useful clean and almost unexploited energy and definitely can behave as
the promising mean for the future energy supply [8]
There are several different methods to take advantage of the solar energy and all the
methods can be distinguished into three group solar parabolic trough solar tower and solar dish
Parabolic trough is constructed by silver coated parabolic mirror and there is a Dewar tube going
through the length of the mirror and set on the focal point all the radiation is concentrated on the
tube and transfer by heat transfer fluid to the thermal energy storage unit Solar tower are used to
5
capture solar energy with thousands of mirrors and focus the concentrated sunlight to the top of
the tower which is located in the middle of the heliostats The thermal energy storage medium
within the tower was heated to high temperature and transferred to thermal energy storage tank
and eventually sent to steam pump The solar dish is built with a large reflective parabolic dish
which concentrates all the received sunlight to one spot There is normally a receiver located on
the focal point and transform the solar energy to other forms of useful energy The working
upper limit temperature of solar parabolic trough system is the lowest among these three systems
normally its maximum working temperature is within the range from 400-500oC the solar tower
has higher maximum working temperature which ranges from 500-1000oC the solar dish has the
highest working upper limit temperature which reaches 700-1200oC [9]
The energy conversion efficiency is the most concerned parameter in the solar energy
storage application and the theoretical and real engineering efficiency are given in fig 11 as
function of temperature The theoretical conversion efficiency can be up to 80 while in real
application the value is always less than 70 regardless of collectors The actual efficiency
increases with temperature in the whole working temperature As a result of that the thermal
energy storage materials in solar parabolic trough for instance should be able to work stably at
the upper limit temperature of this type of collection system which is 500oC to ensure the highest
efficiency [9 10]
6
Fig 11 Theoretical and engineering energy conversion efficiency as function of
temperature
Solar energy can be stored in three major forms sensible heat latent heat and
thermochemical heat Sensible heat storage was utilized based on the heat capacity and the
change as function of temperature of storage materials in the charging and discharging process
which correspond to the absorbing and withdrawing energy processes respectively The sensible
heat stored from the melting point to the maximum working temperature can be expressed by
equation 1 [9]
[1]
Where m is the mass of storage material Tmp and TH are melting point temperature and high
temperature in the same phase respectively Cp(T) is the heat capacity at different temperature
Because the sensible heat storage materials remain in a single phase in the working temperature
range the charging and discharging processes are completely reversible for unlimited cycles
7
Latent heat storage is operated by absorbing and withdrawing energy in the charging and
discharging processes accompanied with fusion of materials [9] The latent heat collected
throughout the working temperature range can be expressed by equation 2 as following
[2]
Where T is temperature in solid state Tmp is melting point temperature of storage material TH is
the high temperature in liquid state and is enthalpy of fusion
Thermochemical heat storage is based on the heat capacity and its change as function of
temperature accompanied with chemical reaction The thermochemical heat collected throughout
the working temperature range can be expressed by equation 3
[3]
Where TL is the low temperature before the reaction TR is the reaction temperature and
is the enthalpy of chemical reaction Because of the destruction of the chemical bonds
in the reaction process the charging and discharging process cannot be completely reversible
which reduces the stability and recyclability of storage operation [10]
Sensible energy storage method is chosen to ensure the efficient usage of solar energy for
parabolic trough system of which the maximum working temperature ranges from 400-500oC
Different from thermochemical heat storage the sensible heat storage can achieve completely
reversible working condition under unlimited cycles Also fig 12 illustrates that the sensible
heat storage materials mainly work in the working temperature range for parabolic trough system
8
and the gravimetric energy storage densities of sensible heat is higher than that of latent heat
materials [9 -11]
Fig 12 Gravimetric storage density for different energy storage systems as function of
temperature
Various materials are chosen to serve as thermal energy storage fluid for sensible heat
such as water thermal oil ionic liquid and molten salt [12] The properties of different heat
transfer fluid determine the performance of solar energy heating system In these days the
efficiency and cost of output of electrical power mainly relies on the parabolic trough solar
power plant and the thermal storage fluid [12] A large investment cost is needed to dispatch
100MW to 200MW energy by consuming the energy transfer fluids Given by this situation the
development of new thermal storage fluid with higher thermal energy storage density is
paramount to lower the expense for generating energy and a lot of effect has been put on design
of new systems [13-16]
9
Water is commonly used as heat transfer and thermal energy storage fluid in industry
because of its low cost high heat capacity and high thermal conductivity However the
limitation for using this medium is also obvious that the temperature range within which the
liquid state can be assured is too small It is well know that water can only serve as thermal
energy storage liquid above the freezing point 0oC and below the boiling temperature 100
oC In
practical experiment the actual temperature range is even less than 100oC because of the large
amount of weight loss near the boiling temperature due to the high vapor pressure Water is
possible to work above 100oC only if high pressure is also applied to avoid the phase
transformation but the cost will be highly increased Accordingly water is only suitable to work
in low temperature below 100oC
Thermal oils are also being used in the parabolic trough solar power plant and have very
low melting point as low as 12oC [17 18] However the application of the oil for the thermal
energy storage liquid is limited by some disadvantages from the physic-chemical properties The
upper limit for this oil is only 300oC and above that the liquid state cannot be maintained
Moreover the low thermal decomposition temperature low density and low heat capacity result
in limited thermal energy storage capacity Since the working temperature range is so narrow the
rankie cycle efficiency is reduced when using the synthetic oil and the cost for generating power
is considered to be very expensive [19 20]
Ionic liquid is another medium served as thermal energy storage fluid The liquid
temperature range of ionic liquid is large which is one of the main advantages of this type of
material The high heat capacity and density ensure the efficiency of thermal energy storage of
10
ionic liquid What‟s more the excellent chemical stability and little vapor pressure increase the
lifetime [21-24] However as a result of the very serve corrosion problem to the liquid container
and the high cost the usage of ionic liquid is still limited
Considering various relative physic-chemical properties of thermal energy storage system
molten salts have been proposed as a suitable group for a wide temperature range application
They are being emphasized in the solar energy applications because of their low melting point
and high upper limit which can increase the stable working range The high heat capacity
increases the thermal energy storage density of the heat storage system excellent thermal
stability and negligible vapor pressure ensure the steadiness of cyclic repeating in the lifetime
[25] low viscosity strengths the mobility and efficiency of the thermal storage liquid low
utilization cost reduce the investment and protect the economy The liquidus temperature range
of the molten salt varies from 150-600oC combination of various salts can bring the melting
down and further increase the working temperature range Due to these properties molten salts
can be excellent thermal energy storage fluid in the solar power generation system
11
CHAPTER 2
LITERATURE REVIEW
Several physical and thermodynamic properties of thermal energy storage fluid play
significant role in determining the efficiency and performance of solar energy storage systems In
order to evaluate the feasibility of systems the physic-chemical properties of several molten salts
should be reviewed The three determining parameter which directly affect the thermal energy
storage capacity in systems are melting point heat capacity and density
There are large amount of melting point data available in the literature for various molten
salt system in previous literatures while those with melting point less than 120oC is very limited
All the previous study on molten salt system revealed that five group of molten salts are
emphasized and commonly used alkai or alkaline nitrates carbonates sulphates chloride and
hydroxides Although most of the systems have the same group of cation the melting point
varies a lot from one to anther due to the different effect of anions
21 Melting point
The melting points of individual and multi-component nitratenitrite systems are listed in
Table 21[26-31] Among those systems solar salt (NaNO3KNO3 6040) is the thermal energy
storage medium which is currently being used with the freezing point of 221oC [27] Although
the melting point for this system is highest in all the candidate mixtures in this group the lowest
12
combined compound cost makes it widely used in solar energy storage field Another ternary
system HITEC which contains NaNO3 KNO3 and NaNO2 has freezing point of 141 oC [28]
This combination brings the melting point down but the lack of combination of optimum features
limits its further application [29] Some mixtures such as LiNO3-Ca(NO3)2-KNO3 are not often
utilized because they increase the compound cost at the same time of lowering the melting point
to around 120oC [30] moreover the decreased melting point is still high compared to the
organic oil There are also several systems have the melting points less than 100oC or even 60
oC
they are not used in the parabolic trough solar power plant due to the decomposition of some
components during high temperature [31]
Table 21 Melting point of various nitrate salt systems
Compound Melting Point (ordmC)
LiNO3 253
NaNO3 307
KNO3 334
Ca(NO3)2 561
Sr(NO3)2 570
Ba(NO3)2 590
NaNO3-NaNO2 221
NaNO3-NaNO2-KNO3 141
NaNO3-KNO3-CaNO3 133
LiNO3-KNO3-NaNO3 120
KNO3-CaNO3-LiNO3 117
LiNO3-KNO3-NHNO3 92
KNO3-NHNO3-AgNO3 52
The melting points of individual and multi-component carbonate systems are listed in
Table 22 [26 32 33] Different from the nitrate salts the melting points for both the individual
13
and multi-component carbonate systems are on the higher side The lowest melting point is
achieved with lithium sodium and potassium carbonate ternary system whose melting point is
still 277oC higher than that of the nitrate ternary system with the same cations [32] Besides
because of the thermal decomposition issue the choice of component involved in the multi-
component carbonate systems is limited Some salt like CaCO3 doesn‟t have stable form at high
temperature and the lack of multi-component system reduces the chance of the synthesis of low
melting point salt mixtures Even though this group of salt is not thermally stable and the
working temperature range is relatively small it is still viewed as possible candidate working at
high temperature due to its low price
Table 22 Melting point of various carbonate salt systems
Compound Melting Point (ordmC)
Li2CO3 732
Na2CO3 858
K2CO3 900
MgCO3 990
Na2CO3-K2CO3 710
Li2CO3-Na2CO3 496
Li2CO3-K2CO3 488
Li2CO3-K2CO3-Na2CO3 397
Alkali and Alkaline fluoridechloride salts are also selected as one possible choice as the
thermal energy storage fluid and the melting point examined from previous literatures are given
in table 23 [34-38] A lot of study has been done for this group of salt and the melting points
were found in the same range as the carbonate group And for the pure salt metal chloride salts
have lower melting point than metal fluoride ones
14
Table 23 Melting point of various fluoridechloride salt systems
Compound Melting Point (ordmC)
LiF 849
NaF 996
KF 858
LiCl 610
NaCl 801
KCl 771
LiF-KF 493
LiF-NaF 652
LiCl-KF 487
LiF-NaF-KF 454
LiF-NaF-KF-MgF2 449
LiF-KF-BaF2 320
LiF-KF-CsF-RbF 256
Several studies were also conducted to determine the melting point of molten hydroxide
salts and the results are shown in Table24 The data of pure salts and multi-component mixtures
merely in this group were not much determined in the literatures Generally they are mixed with
other groups of anion and form some low melting point salt mixtures [39-42] On the basis of the
previous literature data alkali hydroxide salts and their mixture with salts in other groups have
relatively lower melting point compared with pure carbonate and fluoride chloride group salt
mixtures Most of the melting points given in Table 4 are lower than 300oC sodium potassium
hydroxide binary mixture even reaches the melting point below 200oC Accordingly relatively
large temperature range can be obtained by using hydroxide salt mixtures or adding them as
additive
15
Table 24 Melting point of various hydroixde salt systems
Compound Melting Point (ordmC)
LiOH-LiF 427
NaOH-KOH 170
LiOH-NaOH 213
NaOH-NaNO2 232
NaOH-NaNO3 237
NaOH-NaCl-NaNO3 242
NaOH-NaCl-Na2CO3 282
22 Density
For the solar energy storage system density for the thermal energy storage fluid is also
essential parameter The density is needed for the size calculation as function of temperature and
assessing for the thermal stability of thermoclines Besides density as function of temperature is
used to evaluate the volume change in the process of freezing which contributes to potential
stress
Alkalialkaline nitrate salts were studied very much about their density as function of
temperature All the results indicate that the density was decreased linearly as temperature
increases and any specific density value in the molten state can be expressed by equation as
equation 4
= A-BT [4]
Where (gcm3) is the density of salt A (gcm
3) is the initial density value at 0
oC and B
(mgcm3degC) is the density change slope as function of temperature The coefficients are shown in
16
Table 25 for the nitrate group molten salts Among these systems pure sodium nitrate has the
largest value which reveals the high initial density value at low temperature [43] Conversely
lithium nitrate has the lowest value while it presents the smallest decrease trend as temperature
increases [44] The densities and A B values of multi-component nitrate salts were included in
the range of those two salts discussed above
Table 25 Density coefficients A and B of nitrate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiNO3 1922 0556
NaNO3 2334 0767
KNO3 2127 0760
NaNO3-KNO3 2134 0773
KNO3-CaNO3-LiNO3 2172 0735
LiNO3-KNO3-NaNO3 2083 0715
Several experiments were also conducted to measure the density as function of temperature
for the individual and multi-component carbonate salt systems The density of the carbonate salt
also follow the same trend as that of nitrate salt and the temperature dependence of density
followed the linear equation as discussed above It is observed that all the carbonate salts have
higher initial density coefficient A than the nitrate salt The largest value is reached to 2511 and
even the lowest value in this group is greater than the maximum A of nitrate group [45-49]
What‟s more the regression slope coefficient B of carbonate salt is lower compared to that of the
nitrate salt group Accordingly the salts in this group present larger density in the molten state
and the density coefficient A and B are given in Table 26
17
Table 26 Density coefficients A and B of carbonate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
Li2CO3 2303 0532
Na2CO3 2350 0448
Na2CO3-K2CO3 2473 0483
Li2CO3-K2CO3 2511 0599
Li2CO3-Na2CO3 2456 0519
Li2CO3-Na2CO3-K2CO3 2364 0544
Density of metal fluoride and chloride molten salt were also examined and present similar
regression trend as temperature increases The linear temperature dependence is also expressed
by the same equation On the basis of previous literature data the pure chloride salt shows lower
density than the fluoride salt with the same cation in the molten state [49] What‟s more the
sodium halide salt has the largest density value while the lithium halide salt has the lowest value
which is very similar to the nitrate group salt The density determination coefficient A and B are
given in Table27
Table 27 Density coefficients A and B of chloridefluoride salts
Compound A(gcm3) Btimes103(gcm
3degC)
LiCl 1766 0432
NaCl 1991 0543
KCl 1976 0583
LiF 2226 0490
NaF 2581 0636
KF 2469 0651
LiF-NaF 2520 0818
LiCl-NaF-KCl 2436 0742
LiF-NaF-MgF 2240 0701
18
The density measurement of hydroxide was not conducted as much as those three anion
groups discussed above Only few data of density is available for the alkali hydroxide salt when
added into other salt systems and temperature dependence also follows the linear regression
trend [32 41] The density determination coefficient A and B are given in Table 28
Table 28 Density coefficients A and B of molten salt mixture with hydroxide salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiCl-LiOH 16 0443
LiF-LiOH 165 0471
23 Heat capacity
In the heating process the temperature of solar energy storage molten salt is increase by
absorbing energy from the solar radiation Conversely the same amount of heat is released and
applied to heating system in the process of cooling Heat capacity is the amount of heat required
to increase the temperature of certain material by 1 oC and can be viewed as the directly relevant
parameter to the energy storage ability To some extent the large heat capacity assures the
efficiency of the application of solar energy storage materials
The heat capacity of alkalialkaline nitrate salt was investigated for both individual and
multi-component system in the previous literature To simplify the comparison only the heat
capacity value at 500oC is shown in all the following tables In the liquid state the heat capacity
increases with temperature following linear equation and the increasing slope is as small as 10-5
to 10-4
[50 51] Among those alkali nitrate salt systems lithium nitrate has the largest heat
19
capacity at 500oC while potassium nitrate presents the lowest value at that temperature In table
29 the heat capacity results at the selected temperature in literature are given
Table 29 Heat capacity of alkali nitrate salt at 500oC
Compound Heat capacity(JgK)
LiNO3 2175
NaNO3 1686
KNO3 1400
NaNO3-KNO3 1533
LiNO3-KNO3 1642
LiNO3-KNO3-NaNO3 1681
For the carbonate salt systems in the molten state the heat capacity is almost constant and
almost independent with temperature [32 33] Same as the nitrate group salts the heat capacity
for pure carbonate salt decreases as the atomic number of the alkali element increases which
means the value for lithium carbonate is the largest and that of potassium carbonate is the
smallest Generally the heat capacity value for carbonate in molten state is larger than that in
solid state However the sodium-potassium carbonate binary system is an exception for which
the heat capacity in solid state is larger than liquid state In table 210 the heat capacity results of
carbonate salts at the selected temperature in literature are given
Table 210 Heat capacity of alkali carbonate salt at 500oC
Compound Heat Capacity(JgK)
Li2CO3 250
Na2CO3 178
K2CO3 151
Na2CO3-K2CO3 157
20
Li2CO3-K2CO3 160
Li2CO3-Na2CO3 209
Li2CO3-K2CO3-Na2CO3 163
The heat capacity of fluoridechloride salt was measured in several literature and found
that for the pure salt the lithium halide has the biggest heat capacity data in the molten state
while the potassium halides shows the lowest heat capacity value Similar to the carbonate group
the heat capacity value of fluoridechloride salt varies little with temperature in the liquid state
[32 33] The values at 500oC for the alkalialkaline halides are shown in Table 211
Table 211 Heat capacity of fluoridechloride salt at 500oC
Compound Heat Capacity (JgK)
LiCl 148
NaCl 115
KCl 090
LiF-KF 163
NaCl-MgCl2 100
LiF-NaF-KF 155
KCl-MgCl2-CaCl2 092
The heat capacity of pure and multi-component hydroxide salt systems is limited in the
previous literature and the values in the liquid state follow linear equation which is observed for
all the molten salt discussed above [52] The values at 500oC for the alkalialkaline halides are
shown in Table 212
21
Table 212 Heat capacity of hydroxide salt at 500oC
Compound Heat Capacity(JgK)
NaOH 188
LiOH-NaOH 221
NaOH-KOH 182
In summary on the basis of comparison of various physic-chemical properties molten
nitrate slats have relatively low melting point excellent working temperature range reasonable
density and high heat capacity As the result of that molten nitrate salt is suitable to be applied as
the thermal energy storage fluid in the solar energy storage system
22
CHAPTER 3
OBJECTIVES
Based on review of previous literature data it is found that there are several disadvantages
such as the high melting point relatively low density value or poor heat capacity in liquid state
which limit the application of molten salt in certain groups in solar thermal energy storage
system Conversely alkalialkaline nitrate salt is considered as the suitable choice and proposed
as the thermal energy storage liquid for high temperature
Currently the used thermal energy storage liquid is NaNO3 (60mol)-KNO3 (40mol)
binary system (solar salt) which has the melting point at 221oC [30] Although the melting point
for this salt mixture is not the lowest it is still emphasized because of its low investment cost
However there are some drawbacks for this binary nitrate mixture The main disadvantage is
the high melting point In evenings or in winter the molten salt can easily freeze and block the
pipeline As a result of that some auxiliary cost should be added to overcome this problem and
the total investment will be increased
Development and synthesis of newer molten salt mixtures with freezing point lower than
those currently used for thermal energy storage applications is necessary for higher efficiency of
utilization of solar energy and getting rid of any unnecessary cost The approach to develop
lower freezing point molten salt mixtures is by the prediction of new eutectic mixtures and also
23
by the development of new nitrate compounds Besides these two most well known systems
several other mixtures were also studied Preliminary evaluation of several new molten salt flux
systems based on requirements for thermal energy storage systems mainly including freezing
point density heat capacity viscosity and thermal energy storage density The promising
candidate low melting point molten salt system should satisfy the requirements that eutectic
melting temperatures are lower than 220oC and the thermal energy storage densities are higher
than binary solar salt It is known that the melting point can be lowered by the addition of one or
more ABNO3 nitrate compounds where A and B are cations Consequently several multi-
component systems which have more constituent salts than solar salt were came up with and
studied with little fundamental data on the physic-chemical properties at the required operating
conditions available at present
In this thesis the new systems with simulated eutectic compositions were tested for their
experimental melting points heat capacities using the Differential Scanning Calorimetry (DSC)
technique which is considered to be the accurate instrument for thermodynamic data analysis
[53-59] Some significant thermodynamic properties such as heat capacity enthalpy and entropy
and Gibbs energy were calculated in the thesis to evaluate the energy change of the system in the
phase change process and the potential of being applied in the parabolic trough solar power plant
The energy density was obtained by using the experimental measured density and heat capacity
of the mixtures in molten state Finally 9 down-selected systems were present and discussed
24
CHAPTER 4
THERMODYNAMIC MODELING OF SALT SYSTEMS
41 Thermodynamic modeling
To lower the melting point of solar energy storage system multi-component system is
applicable Thermodynamic model was introduced to predict the eutectic temperature of salt
systems based on the Gibbs energies of fusion of individual salt and that of mixing of constituent
binary systems At the eutectic temperature the Gibbs energies in the liquid state and solid state
of salt are equal In thermodynamics Gibbs energy of fusion can be expressed by the equation
given as follows
G = H-TS [5]
Where H is the change of enthalpy of fusion and S is the change of entropy of fusion Equally
the entropy change of fusion can be expressed by differentiating G and the equation is given
[6]
It is known that the change in entropy can be expressed in terms of change in heat capacity in the
melting process as
[7]
25
If the change of heat capacity is assume to be independent of temperature the integral of
from Tm to T can be shown as
[8]
where Sm is the entropy of fusion at the melting point which is equal to Accordingly
Eq8 can be rewritten as
[9]
Substituting Eq 9 in Eq 6 and integrating the equation from Tm to T we get
[10]
Eq 10 illustrates that by using the change of heat capacity melting point and enthalpy of fusion
the Gibbs energy change at any temperature can be obtained
The standard Gibbs energy of fusion of a salt bdquo1‟ can be expressed in terms of the activity
of the salt as
[11]
where is the molar excess Gibbs energy and X1 is the molefraction of the salt bdquo1‟ Gibbs
energy of fusion at any give temperature T is expressed by Eq 7 in terms of its molefraction and
partial molar excess Gibbs energy
26
Take LiNO3-NaNO3-KNO3 as an example in which the integral molar excess Gibbs energy is
composed of the summation of the Gibbs energies of three constituent binary system and one
ternary The expression of the integral excess Gibbs energy is given by Eq12
[12]
Gibbs energies of the three constituent binary systems LiNO3-NaNO3 LiNO3-KNO3 and
NaNO3-KNO3 of the LiNO3-NaNO3-KNO3 ternary system are taken from the literature [48 49]
The Gibbs energies of mixing or the integral excess Gibbs energies of the three constituent
binary systems of the LiNO3-NaNO3-KNO3 ternary system are given below
LiNO3-NaNO3 Binary System
Jmol [13]
LiNO3-KNO3 Binary System
Jmol [14]
NaNO3-KNO3 Binary System
Jmol [15]
When assume the intergral excess Gibbs energy of to be zero the excess Gibbs energy in
the ternary system can be expressed by the summation of three constituent binary systems
[16]
27
Generally the partial molar excess Gibbs energies are reduced from the integral molar
excess Gibbs energy and can be expressed by the generalized equation for certain ldquomrdquo
component salt as
[17]
In the ternary system the i value equals to 12 and 3 and the partial molar excess Gibbs energy
of mixing for each component can be expressed as follows
[18]
[19]
[20]
Based on Eq 7 and the partial molar excess Gibbs energy of individual component the
Gibbs energy in the fusion can be expressed as Eq21- 23
[21]
[22]
[23]
42 Calculations
The fusion of the ternary salt system is defined by solutions of Eq 21-Eq 23 Newton-
Raphson method can be used to solve these three non-linear equations by linearizing the non-
linear equations using the Taylor series and truncating the series to first order derivatives
28
Consider the three non-linear functions F G and H in three variables x y and z The three
equations that are solved for the three variables are written as
F(x y z) = 0
G(x y z) = 0
H(x y z) = 0 [24]
The partial derivatives of the function F with respect to x y and z are given as
[25]
Similarly the partials derivatives can be expressed for the other two functions G and H
Newton-Raphson iterative method of solving the three equations in three variables
essentially deals with the solution of the incremental vector in the matrix equation given below
[26]
For the initial values of x y and z (say xi yi and zi) the right hand side vector contains the
values of the functions at the initial values (xi yi and zi) The 3times3 matrix on the left hand side
contains the partial derivatives of the functions with respect to the three variables at the initial
values Solutions of the matrix equation (Eq 26) result in the increments of the variables x y
and z The variables for the next iteration will then be xi + x yi + y and zi + z The
process of solving the matrix equation (Eq 26) is continued until the increments in the variables
x y and z is less than a very small quantity The iteration process is then said to be
29
converged and the values of the variables at convergence of the solution are the roots of the
system of the three fusion equations
The composition of LiNO3 NaNO3 and KNO3 and the eutectic temperature is solved by
using the Newton-Raphson iterative method Different from the data in previous literature the
eutectic temperature for the ternary is 116oC Besides the composition for each component is
also different from those published in literatures The new molten ternary system is composed of
2592 wt LiNO3 2001 wt NaNO3 and 5407 wt KNO3 The similar method is also applied
to other multi-component systems to determine the composition and eutectic temperature The
predicted melting points for new solar energy storage system are given Table41
Table 41 Calculated composition and melting point of multi-component molten salts systems
System Composition (wt) Calc Tmp
LiNO3 NaNO3 KNO3 NaNO2 KNO2 Mg(NO3)2 MgKN (degC)
Salt 1 259 20 541 - - - - 116
Salt 2 - 161 547 292 - - - 1238
Salt 3 175 142 505 178 - - - 986
Salt 4 115 104 274 - - - 507 986
Salt 5 172 139 476 172 41 - - 957
Salt 6 9 423 336 - 151 - - 1000
Salt 7 193 - 546 237 24 - - 1081
Salt 8 193 - 559 239 - 09 - 1008
Salt 9 154 172 324 - - 83 267 1036
30
CHAPTER 5
EXPERIMENTAL PROCEDURE
51 Melting point determination of molten salt mixtures
511 Materials
Ternary quaternary and quinary nirate and nitrite mixtures were tested in the thesis Most
components in the mixtures don‟t require any pre-preparation and can be used as received The
only exception is new developed MgKN which was composed of 6667 mol KNO3 and 3333
mol Mg(NO3)2 This unique compound is synthesized from magnesium nitrate hexahydrate
(98 Alfa Aesar) and potassium nitrate (ACS 990 min Alfa Aesar) and added into the
mixture as one single component As received magnesium nitrate hexahydrate is dehydrated
before synthesizing MgKN compound Weighted amount of magnesium nitrate taken in a
stainless steel crucible and placed on a hot plate in an argon atmosphere Temperature of the salt
is measured with a thermocouple immersed in the salt The temperature was held at 52315 K for
2 hours The salt solidifies to a white mass The temperature of the salt is then raised to 57315 K
slowly to remove any traces of moisture and to ensure complete dehydration The complete
removal of water is ascertained by weight loss
512 Apparatus and Procedure
31
Differential scanning calorimetry (DSC) analysis was performed using Perkin Elmer
Diamond DSC instrument and the setup is shown in fig 51 Heat flow and temperature can be
recorded in the instrument with an accuracy of 00001 mW and 001 K respectively The
measurements were made under purified nitrogen atmosphere with a flow rate of 20ccmin and at
a heating rate of 5 Kmin
Fig 51 Photography of set-up for DSC equipment
After dehydration if necessary each component was weighed to an accuracy of 01mg with
the electrical balance and mixed thoroughly in a stainless steel crucible Later the mixture is
heated up to certain temperature at which the entire salt melts At this temperature the salt
mixture was held for about 30 minutes The salt mixture is allowed to air cool to ambient
temperature This procedure is repeated 3 to 4 times to get the well-mixed compound Standard
aluminum pan with lid used for DSC measurements are weighed before the experiment Small
amount of the synthesized compound is placed carefully in the aluminum pan and closed with
the lid The lid is crimped by a sample press and the pan is weighed The weight of the sample is
32
determined by removing the weight of the pan and lid For the determination of melting point
and heat capacity (20-25) mg of the sample was used
Perkin-Elmer Diamond Differential Scanning Calorimeter (DSC) is used to measure the
melting point and heat capacity of compound The crimped ample pan was immediately put
inside the sample chamber of DSC after preparation and held at 52315 K for 10 hours to remove
the trace amount of moisture possibly caught in the process of loading sample and also to ensure
a homogeneous mixture In the experimental procedure a temperature range from 29815 K to
52315 K was set with a heating rate of 5 K min
1 followed by a cooling cycle at the same rate
This cycle is repeated for at least 6 times to ensure good mixture of the sample and
reproducibility of the results
52 Heat Capacity determination of molten salt mixtures
To start Cp measurement the same procedure as that of melting point determination is
followed with an addition of bdquoiso-scan-iso‟ steps to the program after 5-cycle temperature scan
Starting from 29815 K the temperature was held for 5 minutes before and after each scan step
Small temperature scan range is chosen to avoid thermal resistance between device and testing
sample except when the temperature is approaching the melting temperature The upper limit for
the Cp measurement was set to 62315 K in our experiments Since the change in the molar heat
capacity of the salt in the liquid state is very small the Cp data in the liquid state can be easily fit
to an equation and extrapolated to higher temperatures To get the value of molar heat capacity
of the sample heat flow curve for the baseline of the empty sample pan also needs to be obtained
immediately following the identical ldquoiso-scan-isordquo steps which were used for the actual sample
33
run The difference of heat flow between the actual crimpled sample and the empty sample pan is
the absolute heat absorbed by the test sample
53 Density determination of molten salt mixtures
Density measurement was carried out with standard densitometer which has fixed volume
Initial weight of the densitometer is measured and noted Salt composition of which the density
is measured is placed in a beaker on a hot place The densitometer is also placed on the same hot
plate The temperature is set to a fixed value above the melting point of the salt and is measured
by a thermocouple After the salt is melted and when the temperature shows stable reading the
molten salt is poured in to the densitometer up to the set mark on the sensitometer bottle The
weight of the densitometer with the molten salt is measured The weight difference between this
weight and the weight of empty densitometer gives the weight of the molten salt at the fixed set
temperature By knowing the fixed volume in the densitometer the density of the salt at that
temperature can be calculated This procedure is repeated at least three times to accurately
determine the density of the salt
34
CHAPTER 6
RESULT AND DISCUSSION
61 Melting point determination
611 DSC equipment calibration
Before the actual melting point measurement pure indium zinc metal and several
individual salts were used to calibrate the DSC equipment For metals only one sharp peak was
observed for each and the heat flow curve for indium metal is shown in fig 61 However larger
and boarder peaks are found for salts just like the condition illustrated in fig 62 for pure
potassium nitrate Based on the results shown in Table 61 the experimental data for melting
points and enthalpies of fusion have excellent agreement with the literature values [60-63] The
variation of point is within 07 and the variation of change of enthalpy is less than 3
Figure 61 Melting point calibration with indium sample
35
Figure 62 Melting point calibration with KNO3 sample
Table 61 Calibration data of melting points with different samples
Sample
Lit
Tmp
Expt
Tmp
Lit
Ttrans
Expt
Ttrans
Lit
ΔHfusion
Expt
ΔHfusion
Lit
ΔHtrans
Expt
ΔHtrans
degC degC degC degC Jg Jg Jg Jg
Indium 1566 1563 - - 286 278 - -
Zinc 4195 4188 - - 1086 1068 - -
LiNO3 2567 2550 - - 3617 3633 - -
NaNO3 3100 3081 2770 2753 1777 1756 147 152
KNO3 3370 3372 1330 1332 993 1005 538 529
612 Results
Differential scanning calorimetry (DSC) was used to determine the melting point and any
solid state phase transitions of the salt mixture A low scanning rate was chosen to record the
heat flow curve as function of temperature in order to improve the sensitivity of detection [64] It
helps to pick up any small endothermic peaks and also avoids the thermal resistance between the
36
internal furnace and sample Nine systems were chosen to test and the eutectic composition is
already listed in Table 41
All the selected systems are composed of alkaline nitrate and nitrite and most of them have
three basic components which are lithium sodium potassium nitrate or nitrite All the quaternary
and quinary systems were developed on the basis of the LiNO3-NaNO3-KNO3 baseline ternary
Figure 63-611 shows the DSC plot of all the salt systems DSC plots for each system were
collected for at least five runs (each run with fresh salt preparation) to ensure the reproducibility
All the onset temperatures peak temperatures predicted temperatures enthalpy of fusion for
melting peaks and the solid phase transformation temperatures are given in Table62
Figure 63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt
37
Figure 64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt
Figure 65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt
38
Figure 66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt
Figure 67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt
39
Figure 68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
Figure 69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
40
Figure 610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt
Figure 611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN salt
Table 62 illustrates that the predicted melting point is close to the experimental
determined value and most deviation is within 10 except for system 9 The great agreement
41
between experimental and calculated data verifies the accuracy and feasibility of the
thermodynamic modeling
Table 62 DSC results of melting point transition point and predicted melting point
System Tmp Ttrans ΔHfusion
Calculated degC Onset degC Peak degC Peak degC Jg
Salt 1 1160 994 1191 1043 600
Salt 2 1238 1150 1240 NA 97
Salt 3 986 940 999 NA 244
Salt 4 986 940 1010 NA 60
Salt 5 957 910 950 NA 62
Salt 6 1000 930 960 NA 86
Salt 7 1081 992 1003 793 60
Salt 8 1008 1010 1019 853 59
Salt 9 1036 834 892 NA 93
613 Discussion
It is observed that the first curve is different from last ones shown in the DSC plots and
this phenomenon is common for all the melting point measurement with DSC technique This
happened because in the first cycle the moisture caught by salt mixture especially the lithium
nitrate was removed in the process of heating Moreover the partially solidified sample in the
sample loading process can be re-homogenized in the first heating cycle [65-67] In figure 63
69 and 610 more than one endothermic peak was found The first smaller endothermic peak
refers to solid state phase transition of the salt mixture The second larger endothermic peak
refers to the melting of the salt Normally the onset temperature of transition is taken as the
experimental transition point for any metallic sample However in case of molten salts mixtures
since the thermal conductivity is low [68-74] the complete transition is ensured only at the peak
42
transition temperature The thermal gradient which exists due to the low thermal conductivity of
the salt results in internal heat flow which enhances the mixing in the salt Thus the transition
temperature is defined as the peak temperature of phase transition For salt No1 the small
endothermic peak happened before and was connected to the main peak which occurred at
39027K The first endothermic peaks for salt No 7 and 8 occurred at almost the same
temperature because of the similar composition for these two compounds Since the small
amount of magnesium nitrate and potassium nitrite contained in these two compounds the small
endothermic peak can hardly be related to these two components Obviously the rest three major
components must have something to do with the first peaks happened before the melting peaks
for both cases Each component among the major three ones were tested to find out any possible
solid phase transition peaks of them and the results shown in Table 63 which reveals that
lithium nitrate doesnt have any phase transition peak in solid state while potassium nitrate and
sodium nitrite both own the solid phase transformation peaks before their melting peaks
Table 63 Fusion and solid phase transition temperature for individual salts
System Tmp degC Ttrans degC ΔHfusion Jg ΔHtrans Jg
LiNO3 2550 - 3633 -
KNO3 3372 1332 1005 529
NaNO2 4311 4170 1119 880
The further investigation was carried out by running the KNO3-NaNO2 (550 wt and 238 wt )
binary compound with the very similar weight percentage as that in salt No 7 (546 wt and
237 wt) and salt No 8 (559wt and 239wt) By converting the weight percentage of the
studied binary system into 100 scale the weight fraction for sodium nitrate and potassium
nitrate can be rewritten as 698wt and 302wt The DSC plot for this binary system was
43
shown in fig 612 Although the solid transition and melting temperature were brought down by
adding lithium nitrate the shape of the plots in fig 69 and 610 are identical to that shown in fig
612 The enthalpy of solid state transformation of the binary salt was also converted to that in
both quaternary systems by using the weight fraction occupied by the binary system and the
comparable change of converted enthalpy between the binary system and two quaternary systems
indicates the relevance of the solid transition peaks in salt 7 and 8 to the combined effect of
potassium nitrate and sodium nitrite
Figure 612 DSC plot of 698wt KNO3- 302wt NaNO2 binary system
The similar analysis was applied to No1 salt to find out the reason for the presence of a
small peak adherent to the main melting peak before the melting point Sodium nitrate and
potassium nitrate binary system was synthesized based on the weight fraction of these two
constituent salts in No 1 salt DSC plot for the sodium nitrate-potassium nitrate binary system in
Fig 613 with the converted composition which is essentially same as that in the No1 ternary
system shows smooth heat flow curve before the melting peak which means the solid transition
peak in ternary is not simply relative to the binary system Assumption was made that the solid
44
phase transformation peak in the ternary salt is resulted from a multiple effect ie the
combination of one of the eutectic binary system involved in the ternary salt mixture and the
other binary system which is composed of the rest components The statement is verified that the
small peak in salt 1 is mainly caused by the solid phase transformation peak in lithium nitrate-
potassium nitrate eutectic binary system given the similar shape of the DSC plots in Fig 614
Since in salt No1 there is excess amount of sodium nitrate to form the lithium nitrate-sodium
nitrate binary system the rest sodium nitrate can interact with potassium nitrate and form new
sodium-potassium nitrate system which is shown in fig615 Besides a solid phase
transformation peak is observed in fig615 which has a very small area and won‟t change the
shape of phase transformation peak in fig614 when these two binary systems are combined and
form salt 1 The enthalpies of solid state transformation in two binary salts were also converted
to that in salt 1 by using the weight fractions occupied by both binary systems The difference
of the change of converted enthalpies between the lithium-potassium nitrate eutectic binary and
ternary system is filled by the binary mixture which is composed of the rest components sodium
nitrate-potassium nitrate The comparable converted values of enthalpy change between salt 1
and its two constituent binary systems further verify the assumption that the solid phase
transformation happened in salt 1 is mainly due to the combined effect of LiNO3-KNO3 eutectic
binary system and NaNO3-KNO3 binary system
45
Figure613 DSC plot of 270wt NaNO3-730wt KNO3 binary system
Figure614 DSC plot of 458wtLiNO3-542wtKNO3 binary system
46
Figure615 DSC plot of 460wt NaNO3-540wt KNO3 binary system
Unlike those discussed mixtures above salt No2 Salt No4 Salt No5 and Salt No6 have
only one relatively board melting peak and the heat flow curve before and after are very stable
Similarly there is no solid transformation peaks observed in salt No3 salt No7 and salt No8
However the heat flow after the melting peak in these cases are not stable and the main
endothermic peak is followed by a small hump which is considered to be the recrystallization
process once the compound entered into the liquid state When the process is finished the heat
flow curve returns to steady state
Heating rate is a significant parameter when collect the heat flow curves by using DSC
technique Fig 616(a) and Fig 616(b) illustrate the difference of melting point for salt No6 due
to the change of heating rate If the heating rate is 20oCmin the peak temperature and onset
temperature for the melting peak is 9669oC and 9221
oC respectively Once the heating rate is
decreased to 5oCmin these two temperatures will also be lowered to 9614
oC and 9190
oC The
difference is resulted from the diverse amount of thermal resistance between the testing sample
and the furnace inside the DSC instrument [75] Under higher heating rate the decisive thermal
47
resistance is raised due to the low thermal conductivity medium between the furnace and the
actual sample The insensitivity of gas heat conduction medium in DSC results each unit of
temperature increase on one side cannot have an immediate response on the other side of the gas
Consequently the sample holder which is connected the furnace has a higher temperature than
that inside the sample In this condition the value of temperature profile collected as the sample
holder temperature is larger than the actual temperature The deviation will be much smaller
when the heating rate is reduced In the case the thermal resistance will be decreased because of
the lower temperature gradient of the gas medium in the heating process As a result of that the
collected temperature from the sensor attached to the sample holder will be very close to the
actual temperature inside the testing sample
Figure 616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 20oCmin
heating rate
48
Figure 616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 5oCmin
heating rate
Besides the difference of temperature while using higher and lower heat rate the solution
of DSC will also be affected by different heating rate Fig 617(a) shows the DSC plot for salt
No 7 using the heating rate as 5oCmin and the DSC plot in Fig 617(b) is collected under the
heating rate as 20oCmin It can be observed that in the lower heating rate two small separated
peaks can be viewed as two parts of the solid phase transformation process while in Fig 617(b)
two small peaks before the melting peak merge and present as a board hump The qualification
of resolution can be executed by the term named resolution factor RMKE which is calculated as
the ratio of the peak heat flow value of the separated peaks to that of the concave point between
two peaks The equation for determining RMIKE is given in Eq 27 [76 77]
RMIKE =hpeakhmin [27]
49
Figure 617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 5oCmin
heating rate
Figure 617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 20oCmin
heating rate
In the case of lower heating rate the RMKE is determined to be 15 and the value for higher
heating rate is not available because the concave point of heat flow doesn‟t exist from
Fig617(b) Since the higher RMKE value indicates better resolution it can be stated that the
50
lower heating rate also results in greater sensitivity of the equipment to pick up any small
endothermic peaks
Besides the down-selected 9 compounds some more salt mixtures were also tested Most
of them were not selected to the final candidate for the thermal energy storage application
because of their higher melting point Table 64 gives some of the trial systems measured with
DSC technique It is illustrated that the melting points of mixtures with lower or even no content
of lithium nitrate turn out to be higher than those with sufficient amount of lithium nitrate For
most of the mixtures with melting point lower than 120oC the amount of lithium nitrate should
be larger than 81wt Also all of the systems in table 64 with lithium nitrate less than 15wt
have melting point higher than 140oC Based on the observation above it is concluded that the
lithium nitrate can be used as an additive to bring the melting point down for thermal energy
storage systems
51
Table 64 Melting points of candidate systems as function of temperatures
System Composition (wt)
Onset
Temp
Peak
Temp
(oC) (
oC)
LiNO3 ndash NaNO3 ndash KNO2 107 459 434 890 910
LiNO3 - KNO3 - NaNO2 196 564 241
1024 1046
LiNO3 - NaNO3 - KNO3 - KNO2 90 423 337 151
930 960
LiNO3 - NaNO3 - NaNO2 - KNO2 81 454 65 401
900 910
LiNO3 - KNO3 - NaNO2 - KNO2 193 546 237 24
992 1003
LiNO3 - KNO3 - NaNO2 ndash Mg(NO3)2 193 559 238 09
1010 1020
LiNO3 - NaNO3 - KNO3 - Mg(NO3)2
- MgK 154 172 324 83 267 834 892
LiNO3 - NaNO3 - KNO2 ndash Ca(NO3)2 14 390 333 263
1250 1470
NaNO3 - KNO3 - NaNO2 - KNO2 425 163 71 341
1407 1447
NaNO3 - KNO3 - KNO2 ndash Mg(NO3)2 432 146 380 42
1386 1421
NaNO3 - NaNO2 - KNO2 - Ca(NO3)2 451 92 410 48
1150 1390
LiNO3 - NaNO3 - NaNO2 - KNO2 -
Ca(NO3)2 15 393 37 323 232 1380 1480
LiNO3 - NaNO3 - KNO2 - Ca(NO3)2 -
Mg(NO3)2 14 379 313 275 20 1339 1534
62 Heat capacity determination
621 Heat capacity calibration
DSC was also calibrated for the heat capacity measurement Lithium nitrate sodium
nitrate and potassium nitrate were examined for the heat capacities from room temperature to
upper limit temperature for the instrument In liquid state the heat capacity values for each salt
can be fit to straight line with trace amount of increasing trend Since the temperature range from
the onset temperature of liquid state to the upper limit of DSC is relatively small the heat
capacity values for pure individual salts can be viewed as constants The comparison between the
theoretical and experimental heat capacity data is given in Table 65 Except lithium nitrate the
52
experimental heat capacities data for the rest two systems are almost same as the literature Even
for lithium nitrate which demonstrates the biggest difference from the literature data the 28
vibration is still within a reasonable range
Table 65 Calibration data of heat capacities with different samples
Sample Lit Cp Expt Cp
JgK JgK
LiNO3 218 212
NaNO3 169 167
KNO3 140 139
622 Results
The materials used in the heat capacity measurements are the same as those in the melting
point experiments Molar heat capacities of the all compound were measured by the DSC
equipment from room temperature to 62315 K The heat flow is recorded as a function of
temperature in ldquoiso-scan-isordquo steps at intervals of 20 K The bdquoiso stage‟ refers to isothermal
holding at a particular temperature bdquoscan stage‟ refers to the heat flow recording at a heating rate
of 5 K min1
up to a an increment of 25 K followed by another isothermal holding stage This is
a standard procedure followed in the measurement of heat capacity of materials using the DSC
equipment [63 64] This procedure of heat capacity measurement has two advantages (i) any
heat fluctuations during the recording are avoided by the isothermal steps and (ii) any phase
transition can be highlighted by the choice of temperature range The absolute heat flow to the
sample is determined by subtracting the heat flow collected by running a baseline curve with an
empty pan Because the heat capacity measurement in the heating process corresponds to
53
collecting the value of required heat flow at each temperature all the heat capacity plots have the
same shape with that of heat flow in the melting point measurements Take the heat capacity plot
of LiNO3-NaNO3-KNO3 ternary system as an instance which is shown in fig 618 the heat
capacity curve also has two different peaks The first little peaks corresponds to one occurs at
39027K which was observed in fig 63 the second large and sharp peak happened right after the
small one is prevalent to the endothermic peak with the peak temperature as 39027 K Similarly
after the phase transformation the heat capacity in liquid state becomes very stable and increase
with temperature linearly with little slope
Fig 618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system as function of
temperature
The heat capacity change as function of temperature for salt No1 was illustrated in fig
619 Based on the trend of heat capacity in the liquid state any value for the system in the liquid
can be extrapolated The expressions for heat capacity in liquid state for the new molten salt
systems were discussed and given in the next sectionTable66 shows the specific heat capacity
54
of the all the selective compounds measured at 62315 K and extrapolated at 77315K Besides
the molar heat capacities at 77315K are given in Table 66 of all the salts
Fig 619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K
Table 66 Heat capacity of selected new TES molten salt mixtures
System Expt (62315K) Extrapolated(77315K) Extrapolated(77315K)
Cp JgK Cp JgK Molar Cp JmolK
Salt 1 153 170 1521
Salt 2 143 168 1515
Salt 3 148 155 2183
Salt 4 153 166 1411
Salt 5 153 170 1440
Salt 6 151 163 1435
Salt 7 156 167 1443
Salt 8 155 168 1410
Salt 9 161 170 1937
55
623 Thermodynamic properties
The standard thermodynamic properties such as entropy enthalpy and Gibbs energy for
salt mixtures are determined from the experimental data of melting point and heat capacity in the
temperature range of the present study and expression for determining these properties are given
in equation 28-30 In thermodynamics all these three properties are related to heat capacity and
its variances with temperature In the studied temperature range (29815K-62315K) they can be
described as expression includes heat capacity
[28]
[29]
[30]
Where Tt is the solid transformation temperature Tmp is the melting point ΔHt is enthalpy of
solid phase transformation and ΔHfusion is enthalpy of fusion The standard thermodynamic
properties entropy enthalpy and Gibbs energies as function of temperature for each compound
are expressed in the following section
6231 LiNO3-NaNO3-KNO3 (Salt 1)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3
compound (i) solid state 1 (32315-38415) K (ii) liquid state (40315-62315) K Accordingly
56
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62311 Heat capacity of solid state 1 (29815-38415) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the solid state 1 in the
temperature range of 29815 to 38415 K is fit to a second order polynomial equation Eqn (31)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[31]
( ) K
R2 = 0982
62312 Heat capacity of liquid state (40315-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a linear equation Eqn (32) gives the linear
equation along with the least square fit parameter (R2) in the temperature range for the liquid
state of the compound
JKmol [32]
57
R2 = 0947
Heat capacity data of the LiNO3-NaNO3-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62313 Thermodynamic properties of solid state 1(29815-38415) K
JKmol [33]
Jmol [34]
[35]
Jmol
62314 Thermodynamic properties of liquid state 2(40315-62315) K
[36]
58
JKmol
Jmol [37]
[38]
Jmol
Among the equations above equation (33)-(35) refer to the thermodynamic properties for
solid state equations (36)-(38) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature ranges for solid and liquid state are
given in Table A1 and A2 in appendix A respectively with the corresponding heat capacity as
function of temperature
6232 NaNO3-NaNO2-KNO3 (Salt 2)
The heat capacity data can be divided into two sections for NaNO3-NaNO2-KNO3
compound (i) solid state 1 (32315-39215) K (ii) liquid state (41315-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62321 Heat capacity of solid state 1 (29815-39215) K
59
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the solid state in the
temperature range of 29815 to 39215 K is fit to a second order polynomial equation Eqn (39)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[39]
( ) K
R2 = 0978
62322 Heat capacity of liquid state (40315-62315) K
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a second order polynomial equation Eqn (40)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[40]
R2 = 0941
60
Heat capacity data of the NaNO3-NaNO2-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62323 Thermodynamic properties of solid state 1(29815-39215) K
JKmol [41]
Jmol [42]
[43]
Jmol
62324 Thermodynamic properties of liquid state 2(40315-62315) K
JKmol [44]
61
Jmol [45]
[46]
Jmol
Among the equations above equation (41)-(43) refer to the thermodynamic properties for
solid state equations (44)-(46) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table B1 and B2 in appendix B respectively with the corresponding heat capacity as
function of temperature
6233 LiNO3-NaNO3 -KNO3-MgK (Salt 3)
The heat capacity data can be divided into two sections for LiNO3-NaNO3 -KNO3-MgK
compound (i) solid state 1 (29815-36415) K (ii) liquid state (42115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62331 Heat capacity of solid state 1 (29815-36415) K
62
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the solid state in the
temperature range of 29815 to 36415 K is fit to a second order polynomial equation Eqn (47)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[47]
( ) K
R2 = 0995
62332 Heat capacity of liquid state (42115-62315) K
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the liquid state in the
temperature range of 42115 to 62315 K is fit to a second order polynomial equation Eqn (48)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[48]
R2 = 0963
63
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
62333 Thermodynamic properties of solid state 1(29815-36415) K
JKmol [49]
Jmol [50]
[51]
Jmol
62334 Thermodynamic properties of liquid state 2(42115-62315) K
64
JKmol [52]
Jmol [53]
[54] [29]
Jmol
Among the equations above equation (49)-(51) refer to the thermodynamic properties for
solid state equations (52)-(54) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table C1and C2 in appendix C respectively with the corresponding heat capacity as
function of temperature
6234 LiNO3-NaNO3-KNO3-NaNO2 (Salt 4)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-NaNO2
compound (i) solid state 1 (29815-36315) K (ii) liquid state (38115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62341 Heat capacity of solid state 1 (29815-36315) K
65
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the solid state in the
temperature range of 29815 to 36315 K is fit to a second order polynomial equation Eqn (55)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[55]
( ) K
R2 = 0995
62342 Heat capacity of liquid state (38115-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the liquid state in the
temperature range of 38115 to 62315 K is fit to a second order polynomial equation Eqn (56)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[56]
R2 = 0972
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
66
62343 Thermodynamic properties of solid state 1(29815-36315) K
JKmol [57]
Jmol [58]
[59]
Jmol
62344 Thermodynamic properties of liquid state 2(38115-62315) K
JKmol [60]
Jmol [61]
67
[37]
Jmol [62]
Among the equations above equation (57)-(59) refer to the thermodynamic properties for
solid state equations (60)-(62) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table D1 and D2 in appendix D respectively with the corresponding heat capacity as
function of temperature
6235 LiNO3-NaNO3-NaNO2-KNO3-KNO2 (Salt 5)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-NaNO2-KNO3-
KNO2 compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62351 Heat capacity of solid state 1 (29815-35915) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
in the temperature range of 29815 to 35915 K is fit to a second order polynomial equation Eqn
(63) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
68
[63]
( ) K
R2 = 0996
62352 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the liquid
state in the temperature range of 37515 to 62315 K is fit to a second order polynomial equation
Eqn (64) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[64]
R2 = 0969
Heat capacity data of the LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62353 Thermodynamic properties of Solid state 1(29815-35915) K
JKmol [65]
69
Jmol [66]
[67]
Jmol
62354 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [68]
Jmol [69]
[45]
Jmol [70]
70
Among the equations above equation (65)-(67) refer to the thermodynamic properties for
solid state equations (68)-(70) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table E1 and E2 in appendix E respectively with the corresponding heat capacity as
function of temperature
6236 LiNO3-NaNO3-KNO3-KNO2 (Salt 6)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-KNO2
compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62361 Heat capacity of solid state 1 (29815-36515) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the solid state in the
temperature range of 29815 to 36515 K is fit to a second order polynomial equation Eqn (71)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[71]
( ) K
R2 = 0998
71
62362 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the liquid state in the
temperature range of 37515 to 62315 K is given in Table 20 The data is fit to a second order
polynomial equation Eqn (72) gives the linear equation along with the least square fit parameter
(R2) in the temperature range for the liquid state of the compound
[72]
R2 = 0953
Heat capacity data of the LiNO3-NaNO3-KNO3-KNO2 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62363 Thermodynamic properties of solid state 1(29815-35915) K
JKmol [73]
Jmol [74]
72
[75]
Jmol
62364 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [76]
Jmol [77]
Jmol [78]
Among the equations above equation (73)-(75) refer to the thermodynamic properties for
solid state equations (76)-(78) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
73
given in Table F1 and F2 in appendix F respectively with the corresponding heat capacity as
function of temperature
6237 LiNO3-KNO3-NaNO2-KNO2 (Salt 7)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62371 Heat capacity of solid state 1 (29815-35415) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 1 in
the temperature range of 29815 to 35415 K is fit to a second order polynomial equation Eqn
(79) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[79]
(29815-35415) K
R2 = 0993
62372 Heat capacity of solid state 2 (36215-37315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 2 in
the temperature range of 36215 to 37315 K is fit to a second order polynomial equation Eqn
74
(80) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 2 of the compound
[80]
R2 = 0977
62373 Heat capacity of liquid state (37915-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the liquid state in the
temperature range of 37915 to 62315 K is fit to a linear equation Eqn (81) gives the
polynomial equation along with the least square fit parameter (R2) in the temperature range for
the liquid state of the compound
[81]
R2 = 0961
Heat capacity data of the LiNO3-KNO3-NaNO2-KNO2 compound in the two solid states
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62374 Thermodynamic properties of solid state 1(29815-35415) K
75
JKmol [82]
Jmol [83]
[84]
Jmol
62375 Thermodynamic properties of solid state 2(36215-37315) K
JKmol [85]
Jmol [86]
76
[87] [62]
Jmol
62376 Thermodynamic properties of liquid state (37915-62315) K
JKmol [88]
Jmol [89]
Jmol [90]
Among the equations above equation (82)-(84) refer to the thermodynamic properties for
solid 1 equation (85)-(87) refer to the thermodynamic properties for solid 2 equations (88)-(90)
refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy values
77
in the studied temperature range for solid 1 solid 2 and liquid state are given in Table G1-G3 in
appendix G respectively with the corresponding heat capacity as function of temperature
6238 LiNO3-KNO3-NaNO2-Mg(NO3)2 (salt 8)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62381 Heat capacity of solid state 1 (29815-33715) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid
state 1 in the temperature range of 29815 to 33715 K is fit to a second order polynomial
equation Eqn (91) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the solid state 1 of the compound
[91]
(29815-33715) K
R2 = 0994
62382 Heat capacity of solid state 2 (36115-36415) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid state 2
in the temperature range of 36115 to 36415 K is given in Table 4 The data is fit to a second
78
order polynomial equation Eqn (92) gives the polynomial equation along with the least square
fit parameter (R2) in the temperature range for the solid state 2 of the compound
[92]
R2 = 0992
62383 Heat capacity of liquid state (41115-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the liquid state in
the temperature range of 41115 to 62315 K is given in Table 5 The data is fit to a linear
equation Eqn (93) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the liquid state of the compound
[93]
R2 = 0934
Heat capacity data of the LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the two solid
states follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62384 Solid state 1(29815-35415) K
79
JKmol [94]
Jmol [95]
[96]
Jmol
62385 Solid state 2(36115-36415) K
JKmol [97]
80
Jmol [98]
[99] [74]
Jmol
62386 Liquid state (41115-62315) K
JKmol [100]
Jmol [101]
Jmol [102]
Among the equations above equation (94)-(96) refer to the thermodynamic properties for
solid 1 equation (97)-(99) refer to the thermodynamic properties for solid 2 equations (100)-
(102) refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy
81
values in the studied temperature range for solid 1 solid 2 and liquid state are given in Table H1
and H2 in appendix H respectively with the corresponding heat capacity as function of
temperature
6239 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK(Salt 9)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-
Mg(NO3)2-MgK compound (i) solid state 1 (29815-35315) K (ii) liquid state (39115-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62391 Heat capacity of solid state 1 (29815-35315) K
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state in the temperature range of 29815 to 35315 K is fit to a second order polynomial equation
Eqn (103) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[103]
( ) K
R2 = 0996
62392 Heat capacity of liquid state (39115-62315) K
82
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the liquid
state in the temperature range of 39115 to 62315 K is fit to a second order polynomial equation
Eqn (104) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[104]
R2 = 0951
Heat capacity data of the LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62393 Solid state 1(29815-35315) K
JKmol [105]
Jmol [106]
83
[107]
Jmol
62394 Liquid state 2(39115-62315) K
JKmol [108]
Jmol [109]
[110]
Jmol
Among the equations above equation (105)-(107) refer to the thermodynamic properties
for solid state equations (108)-(110) refer to thermodynamic properties of the liquid The
entropy enthalpy and Gibbs energy values in the studied temperature range for solid and liquid
state are given in Table I1 and I2 in appendix I respectively with the corresponding heat
capacity as function of temperature
84
624 Discussion of Gibbs energy change for molten salts
The Gibbs energy change data as function of temperature for 9 systems are given in fig
620 and the values at 62315K are shown in Table 67 Every system demonstrates continuous
curve throughout the whole studied temperature range Most of systems have similar Gibbs
energy change values for each temperature spot due to the comparable compositions and
properties of constituent salts However salt 3 and salt 9 Both of these salts have certain
amount of MgKN compound which presents large absolute amount of change of Gibbs energy in
the same studied temperature range [66] Since the change of Gibbs energy for multi-component
mixture is relevant to that of each constituent salt the large absolute value of ΔG of MgKN
mainly contributes to the largely negative value of salt 3 and salt 9 shown in fig 620 Besides
it is observed that most systems contain nitrite salts present lower absolute value of Gibbs energy
change For example salt 1 doesn‟t include any nitrite salt and has a relatively high absolute
value of Gibbs energy change as 1704kJmol while other systems having nitrite salts show lower
value varies from 1372kJmol to 1592kJmol
85
Fig 620 Change of Gibbs energy as function of temperature for molten salt systems
Table 67 Change of Gibbs energy values at 62315K for molten salt systems
SNo System ΔG(kJmol)
1 LiNO3-NaNO3-KNO3 1704
2 NaNO3- NaNO2- KNO3 1372
3 LiNO3- NaNO3- KNO3- MgKN 2807
4 LiNO3- NaNO3- KNO3- NaNO2 1443
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1441
6 LiNO3-NaNO3-KNO3-KNO2 1570
7 LiNO3-KNO3-NaNO2-KNO2 1592
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1583
9 LiNO3-NaNO3-KNO3-Mg(NO3)2 -MgKN 2217
86
63 Density determination
631 Density calibration
Several pure molten salts are used to calibrate the density measurement set-up before the
actual density measurement All the density values decrease as function of temperature in the
liquid state and follow the same linear equations as described in eq 4 The experimental values
at 350oC for KNO3 NaNO3 and LiNO3 are selected to compare with the literature data at the
same temperature The results are shown in Table 68 Based on the comparison of the literature
data and the experimental data the variation of density for molten nitrate salt is within in 4
Table 68 Calibration of density measurements with different pure nitrate salts
Sample Literature density Experimental density
gcm3 gcm
3
LiNO3 1727 1701
NaNO3 2066 2144
KNO3 1860 1855
632 Results and discussions
The density result of the salt as function of temperature is plotted for all the salts in Figure
621 and Figure 622 It is observed that the temperature dependence of density above the
melting point is different from that in solid state As known in solid state the density of salt has
an exponential relation with temperature while in these liquid cases the density values have
linearly dependence with temperature The stable variation as function of temperature allows the
extrapolation of density at even higher temperature The regression analysis is performed to get
the coefficient used for describing eq 4 and the results for the coefficients are shown in
87
Table69 [78-80] It is observed that the change of composition is implied on the coefficient A
which indicates the initial point at 150oC The temperature dependence coefficient B doesn‟t
change much with composition which may be mainly affected by the group of anion and cation
Table 69 Coefficient A and B for density determination of salt 1-salt 9
Salt No System A Btimes10
3
(gcm3) (gcm
3degC)
1 LiNO3-NaNO3-KNO3 2032 0493
2 NaNO3- NaNO2- KNO3 2081 0570
3 LiNO3- NaNO3- KNO3-MgKN 2055 0526
4 LiNO3- NaNO3- KNO3- NaNO2 2033 0520
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 2018 0485
6 LiNO3-NaNO3-KNO3-KNO2 2060 0554
7 LiNO3-KNO3-NaNO2-KNO2 2048 0554
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 2044 0524
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 2060 0566
Figure 621 The densities of the salt 1-salt 5 as function of temperature
88
In figure 621 all the density values are clustered around 198gcm3 at 150
oC to
186gcm3 at high temperature end and the deviation of density between all the mixtures is within
in 0047g cm3 Among all the salt mixtures the NaNO3-NaNO2-KNO3 ternary system
demonstrates the highest density value throughout the studied temperature range and LiNO3-
NaNO3-KNO3 ternary system LiNO3- NaNO3-KNO3-NaNO2 quaternary system and LiNO3-
NaNO3-KNO3-NaNO2-KNO2 quinary system show densities at the bottom side of Fig 621 For
salt 2 which doesn‟t contain any lithium nitrate the density at every selected temperature spot
is obviously higher than that of salt 1 4 and 5 which have large amount of lithium nitrate
Moreover the salt 3 which contains the relatively small amount of lithium nitrate stays in
between of salt 1 and salt 2 This comparison illustrates that the addition of lithium nitrate has
an offsetting effect on density for molten salt and it is consistent with previous literature reports
[81] The four systems presented in figure 622 also show even closer density values in the
studied temperature range Similarly salt 6 which contains the least lithium nitrate has the
largest density Salt 7 and salt 8 have almost same composition for the three dominating
components as a result of that the density curves for both mixtures are determined by the same
regression coefficient A and B Moreover the larger amount of lithium nitrate involved in these
two salt mixtures contributes to the lower density given in figure622 which further verifies the
significantly offsetting effect of lithium nitrate on density
89
Figure 622 The densities of the salt 6-salt 9 as function of temperature
The salt mixtures with maximum and minimum amount of lithium nitrate were plotted and
compared with equimolar NaNO3-KNO3 binary system and pure KNO3 salt in Fig623 [82 83]
It is observed that the NaNO3-KNO3 binary system has very similar density value to that of salt
2 because of the analogous type and composition of component in both salts The density of
pure KNO3 is slightly lower than the binary salt mixture which indicates the density of NaNO3 is
close to but higher than KNO3 in the studied temperature range Salt 1 shows the lowest density
in Fig623 due to the offsetting effect on density caused by lithium nitrate which has been
discussed above
90
Figure 623 Density of the salt 1 salt 2 as function of temperature compared to the
equimolar NaNO3-KNO3 binary system and pure KNO3
64 Thermal energy storage density of molten salts
The energy density which is considered as one of the most significant parameters of TES
application can be evaluated by calculation based on the measured density heat capacity and
working temperature range The equation of the thermal energy storage density (E) at working
temperature of 500oC is expressed in equation 111
E = Cp (500-Tm) [111]
Where Cp and are extrapolated heat capacity and density at 500oC respectively Tm is
melting point for salt mixture The extrapolation of density and heat capacity is based on the
linear temperature dependence for both parameters in molten state and the values are shown in
Table 610
91
Table 610 Extrapolated value of density and heat capacity at 500oC of salt 1-salt 9
Salt
No System
Density Heat Capacity
(gmL) (JgK)
1 LiNO3-NaNO3-KNO3 1785 170
2 NaNO3- NaNO2- KNO3 1796 168
3 LiNO3-NaNO3-KNO3-MgK 1773 155
4 LiNO3- NaNO3- KNO3- NaNO2 1792 166
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1796 170
6 LiNO3-NaNO3-KNO3-KNO2 1783 163
7 LiNO3-KNO3-NaNO2-KNO2 1771 167
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1782 168
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 1777 170
The calculated energy density for each salt is given in Table 611 compared with that of
solar salt (NaNO3-KNO3) All the new synthesized salt mixtures have significantly higher energy
density than solar salt and salt 3 shows the highest energy density among the new salts
Although salt 1 has higher heat capacity and good melting point the energy density is still the
lowest among new salt mixtures given by the effect of low density The conclusion can be drawn
from these observations that the energy density is a property affected by multiple parameters and
every part plays an important role in determining the efficiency of energy storage of salt
mixtures
92
Table 611 Energy density of salt 1-salt 9 compare to solar salt
The gravimetric storage density of new molten salts are listed in Table 612 and compared
with those different storage systems in fig 624 It is found that in the parabolic trough working
temperature range the gravimetric storage densities of new molten salts are located on the higher
side Even though some reported sensible energy storage liquids have larger gravimetric density
values than the new salts the maximum working temperatures reveal the instable working
condition at 500oC Taking conversion efficiency thermal stability and gravimetric storage
density into considerations the new molten salts are the most suitable choices of the sensible
heat storage for parabolic trough application
Salt No System Energy Density
500degC (MJm3)
0 NaNO3- KNO3 756
1 LiNO3-NaNO3-KNO3 1162
2 NaNO3- NaNO2- KNO3 1135
3 LiNO3-NaNO
3-KNO
3-MgKN 1099
4 LiNO3- NaNO
3- KNO
3- NaNO
2 1189
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1232
6 LiNO3-NaNO3-KNO3-KNO2 1174
7 LiNO3-KNO3-NaNO2-KNO2 1183
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1192
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 1242
93
Fig 624 Gravimetric storage density comparison of different energy storage systems as
function of temperature
Table 612 Gravimetric storage densities for solar salt and new molten salts
Salt
No System
Gravimetric Storage Density
500degC (kJkg)
0 NaNO3- KNO3 404
1 LiNO3-NaNO3-KNO3 560
2 NaNO3- NaNO2- KNO3 533
3 LiNO3-NaNO
3-KNO
3-MgKN 575
4 LiNO3- NaNO
3- KNO
3- NaNO
2 612
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 595
6 LiNO3-NaNO3-KNO3-KNO2 594
7 LiNO3-KNO3-NaNO2-KNO2 604
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 610
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 649
94
CHAPTER 7
CONCLUSION
The melting points of new molten salts were experimentally determined using DSC
Different from metals the melting point was chosen as the peak temperature rather than onset
temperature of the endothermic peak due to the low thermal conductivity and broad phase
transition range of the molten nitride salt mixture All of the nine new molten salts have melting
points from 89oC to 124
oC which are much lower than current sodium-potassium binary solar
salt Some systems such as salt No1 No7 and No8 have solid phase transformation observed
from the DSC plots It is found that the phase transformations of salt No 7 and No 8 are mainly
contributed to the KNO3-NaNO2 binary system while the small solid transformation peak of salt
No1 is resulted from the combined effect of the KNO3-LiNO3 eutectic binary system involved in
the ternary salt and another binary system which is composed of the rest components The
heating rate of DSC was revealed as a significant parameter for the any endothermic peak
determination When using lower heating rate the thermal resistance between the studied sample
and the furnace will be minimal and the resolution of peak detection will be enhanced
The heat capacities of all the multi-component salts (1 to 9) were determined using DSC
and found varying from 143 to 161 JgK at 350oC The heat capacity in the liquid state
demonstrates linear increase trend as function of temperature On the basis of that the heat
capacity was extrapolated to parabolic trough operating temperature of 500oC Besides heat
capacity data as function of temperature are fit to polynomial equation and thermodynamic
95
properties like enthalpy entropy and Gibbs energies of the compound as function of temperature
are subsequently deduced
Experimental measurements of density of multi-component systems were conducted as
function of temperature in their liquid state In liquid state the density values decrease linearly
as temperature increases The results of those mixtures were compared to the solar salt and
individual constituent salts The comparison demonstrates that the addition of lithium nitrate
lowers the density which is consistent with the observation that lithium nitrate has the lowest
density among all the individual salts in the studied temperature range On the basis of densities
heat capacities and the melting points energy storage density for all the new salts were
calculated and compared to the binary solar salt Among all the new molten salt systems
LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN quinary system (salt 9) presents the largest thermal
energy storage density as well as the gravimetric density values Moreover the larger thermal
energy storage as well as gravimetric storage densities compared to the solar salt indicate the
better energy storage capacities of new salts for solar power generation systems
96
REFERENCES
[1] JF Manwell JG McGowan and AL Rogers Wind Energy Explained-Theory Design and
Application second edition John Wiley and sons Ltd UK 2009
[2] MJ Pasqualetti Morality space and the power of wind-energy landscapes Geographical
Review 90 2000 381-394
[3] DG Fink and HW Beaty Standard Handbook for Electrical Engineers Eleventh Edition
McGraw-Hill New York 1978
[4] R Bertani Geothermal Energy An Overview on Resources and Potential Proceedings of the
International Conference on National Development of Geothermal Energy Use 2009 Slovakia
[5] TA Volk LP Abrahamson EH White E Neuhauser E Gray C Demeter C Lindsey J
Jarnefeld DJ Aneshansley R Pellerin and S Edick Developing a Willow Biomass Crop
Enterprise for Bioenergy and Bioproducts in the United States Proceedings of Bioenergy
2000 October 15-19 2000 Buffalo New York USA
[6] M Asplund N Grevesse and AJ Sauval The new solar abundances-Part I the
observations Communications in Asteroseismology 147 2006 76-79
[7] DRWilliams Sun Fact Sheet NASA 2004
httpnssdcgsfcnasagovplanetaryfactsheetsunfacthtml
[8] U Herrmann Survey of Thermal Energy Storage for Parabolic Trough Power Plants Journal
of Solar Energy Engineering 124 2002 145-152
[9] Rocket Research Company Chemical energy storage for solar thermal conversion SAND79-
8198 Livermore Sandia National Laboratories 1979
97
[10] A Steinfeld and R Palumbo Solar thermochemical process technology Encyclopedia of
Physical Science and Technology 2001 237-256
[11] EA Fletcher Solar thermal processing a review Journal of Solar Energy Engineering
2001 63-74
[12] R W Bradshaw and Nathan P Siegel Molten Nitrate Salt Development for Thermal
Energy Storage in Parabolic Trough Solar Power Systems of the Energy Sustainability 2008
Conference August 10-14 2008 Jacksonville Florida USA
[13] B Kelly H Price D Brosseau and D Kearney Adopting NitrateNitrite Salt Mixtures as
the Heat Transport Fluid in Parabolic Trough Power Plants Proceedings of the Energy
Sustainability 2007 Conference June 27-30 2007 Long Beach CA
[14] H Reilly and G Kolb Evaluation of Molten Salt Power Tower Technology Based on
Experience at Solar Two SAND2001-3674 Sandia National Laboratories 2001
[15] T Wendelin ldquoParabolic Trough VSHOT Optical Characterization in 2005-2006rdquo NREL
wwwnrelgovdocsfy06osti40024pdf
[16] RB Diver C Andraka S Rawlinson V Goldberg and G Thomas The Advanced Dish
Development System Project ASME Proceedings of Solar Forum 2001 Washington DC
[17] S D Odeh G L Morrison and M Behnia Modelling of parabolic trough direct steam
generation solar collectors Solar Energy 62 1998 396-406
[18] V Heinzel H Kungle and M Simon Simulation of a parabolic trough collector ISES
Solar World Congress Harare Zimbabwe 1-10
[19] S D Odeh G L Morrison and M Behnia Modeling of Parabolic Trough Direct
Generation Solar Collectors Solar Energy 62 1998 395-406
[20] Ezzat Optimum Working Fluids for Solar Powered Rankine Cycle Cooling of Buildings
Solar energy 25 1980 235-241
98
[21] R G Reddy Ionic Liquids How well do we know them editorial Journal of Phase
Equilibria and Diffusion 27 2006 210-211
[22] M Zhang and R G Reddy Application of [C4min][Tf2N] Ionic Liquid as Thermal
Storage and Heat Transfer Fluids editor J Weidner ECS Transactions 2 (28) 2007 27-32
[23] M Zhang and R G Reddy Evaluation of Ionic Liquids as Heat Transfer Materials in
Thermal Storage Systems Energy Energy Materials editors F Dogan M Awano D Singh
and B Tuttle ASM International Materials Park Ohio USA MSampT‟07 2007 151-160
[24] R G Reddy Novel Applications of Ionic Liquids in Materials Processing Advanced
Structural and Functional Materials Design 2008 Journal of Physics Conference Series (JPCS)
165 2009 1-6
[25] RW Bradshaw and DE Meeker High-temperature stability of ternary nitrate molten
salts for solar thermal energy systems Solar Energy Materials 21 1990 51-60
[26] AS Trunin Designing and investigations of salt systems for solar energy utilization
Utilization of sun and other radiation sources in materials research Kiev Naukova Dumka 1983
p 228-38
[27] D J Rogers and G J Janz Melting-crystallization and premelting properties of sodium
nitrate-potassium nitrate Enthalpies and heat capacities Journal of Chemical and Engineering
Data 27 1982 424-428
[28] D Kearney U Herrmann P Nava and B Kelly Assessment of a molten salt heat transfer
fluid in a parabolic trough solar field Journal of Solar Energy Engineering 125 2003 170-176
[29] Q Peng J Ding X Wei J Yang and X Yang The preparation and properties of multi-
component molten salts Applied Energy 87 2010 2812-2817
[30] E M Levin C R Robbins and H F McMordie Phase Diagrams for Ceramists American
Ceramic Society 1964
[31] J C Oxley J L Smith E Rogers and M Yu Ammonium nitrate thermal stability and
explosivity modifiers Thermochimica Acta 384 2002 23-45
99
[32] LG Marianowski and HC Maru Latent heat thermal energy storage systems above
4508oC Proceedings of 12th intersociety energy conversion engineering conference 1977 55-
66
[33] HC Maru JF Dullea A Kardas L Paul LG Marianowski E Ong et al Molten salts
energy storage systems Chicago Final Report of the Institute of Gas Technology 1978
[34] WM Philips and JW Stears Advanced latent heat of fusion thermal energy storage for
solar power stations Proceedings of 20th intersociety energy conversion engineering conference
2 1985 384-391
[35] KE Mayo Heat source systems USA Patent 3605720 1971
[36] JI Eichelberger and HD Gillman Investigation of metal fluoride thermal energy storage
material Proceedings of 12th intersociety energy conversion engineering conference 1977 567-
574
[37] GR Heidenreich and MB Parekh Thermal energy storage for organic Rankine cycle solar
dynamic space power systems Proceedings of 21st intersociety energy conversion engineering
conference 2 1986 791-797
[38] IK Garkushin AC Trunin TT Miftakhov and MA Dibirov Salt heat storage
composition USSR Patent 1036734 1983
[39] W M Philips and J W Stears Advanced latent heat of fusion thermal energy storage for
solar power stations In Proceedings of 20th intersociety energy conversion engineering
conference 2 1985 384-391
[40] Y Takahashi M Kamimoto Y Abe R Sakamoto K Kanari and T Ozawa Investigation
of latent heat-thermal energy storage materials IV Thermoanalitical evaluation of binary eutectic
mixtures of NaOH with LiOH or KOH Thermochim Acta 121 1987 193-202
[41] C E Birchenall and A F Riechman Heat storage in eutectic alloys Metall Trans A
11A(8) 1980 1415-1420
100
[42] Y Takahashi R Sakamoto and M Kamimoto Heat capacities and latent heats of LiNO3
NaNO3 and KNO3 International Journal of Thermophysics 9(6) 1988 1081-1090
[43] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate Mixtures
Journal of Chemical Engineering Data 8(3) 1963 469
[44] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical Engineering Data 6 (4) 1961 493
[45] GF Petersen WA Ewing and G P Smith Densities of Some Salt Mixtures Journal of
Chemical Engineering Data 6 (4) 1961 540
[46] G J Janz and M R Lorenz Precise Measurement of Density and Surface Tension at
Temperatures up to 1000degC in One Apparatus Review of Scientific Instruments 31 (1) 1960
18-23
[47] G J Janz C B Allen N P Bansal R M Murphy and R P Tomkins Physical Properties
Data Compilations Relevant to Energy Storage II Molten Salts Data on Single and Multi-
Component Salt Systems National Bureau of Standards NSRDS-NBS 61 Part II April 1979
[48] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation Equations
for Critically Evaluated Density Surface Tension Electrical Conductance and Viscosity Data
Journal of Physical and Chemical Reference Data 17 1988 2
[49] A T Ward and G J Janz Molten Carbonate Electrolytes Electiral Conductance Density
and Surface Tension of Binary and Ternary Eleclrochimica Acta 10 1965 849-857
[50] Y Takahashi R Sakamoto and MKamimoto Heat Capacities and Latent Heat of LiNO3
NaNO3 amp KNO3 International Journal of Thermophysics 9 1998 1081-1090
[51] R W Carling Heat capacities of NaNO3 and KNO3 up to 800 K Thermochimica Acta 60
1983 265-275
[52] Y Takahashi Latent heat measurement by DSC with sapphire as standard material
Thermochim Acta 88(1) 1985 199-204
101
[53] GW Hohne W Hemminger and HJ Flammersheim Differential Scanning Calorimetry
Springer-Verlag Berlin 1996
[54] W Hemminger and G Hohne Calorimetry Fundamentals and Practice Verlag Weinheim
1984
[55] M Merzlyakov and C Schick Thermal conductivity from dynamic response of DSC
Thermochimica Acta 377 2001 183-191
[56] T Kousksou A Jamil S Gibout and Y Zeraouli Thermal analysis of phase change
emulsion Journal of Thermal Analysis and Calorimetry 96 2009 841-852
[57] A Jamil T Kousksou K El Omari Y Zeraouli and Y Le Guer Heat transfer in salt
solutions enclosed in DSC cells Thermochimica Acta 507-508 2010 15-20
[58] MJ Richardson Quantitative aspects of differential scanning calorimetry Thermochimica
Acta 300 1997 15-28
[59] S Rudtsch Uncertainty of heat capacity measurements with differential scanning
calorimeters Thermochimica Acta 382 2002 17-25
[60] M J Maeso and J Largo The phase diagram of LiNO3-NaNO3 and LiNO3-KNO3 the
behavior of liquid mixtures Thermochimica Acta 223 (1993) 145-156
[61] O J Kleppa A new twin high-temperature reaction calorimeter The heats of mixing in
liquid sodium-potassium nitrates Journal of Physical Chemistry 64(12) (1960) 1937-1940
[62] G W H Hhne H K Cammenga W Eysel E Gmelin and W Hemminger The
Temperature Calibration of Scanning Calorimeters Thermochimica Acta 160 1990 1-12
[63] L B Pankratz Thermodynamic Properties of Carbides Nitrides and Other Selected
Substances U S Bureau of Mines Bulletin 696 1994
[64] M Zhang and R G Reddy Thermodynamic properties of C4mim[Tf2N] ionic liquids 0 2
2010 71-76
102
[65] D Mantha T Wang and R G Reddy Thermodynamic Modeling of Eutectic Point in the
LiNO3-NaNO3-KNO3 Ternary System Journal of Phase Equilibria and Diffusion 2011
(accepted)
[66] R G Reddy T Wang and D Mantha Determination of thermodynamic properties of
2KNO3Mg(NO3)2 Thermochimica Acta 2011 (submitted)
[67] T Wang D Mantha and R G Reddy Thermal stability of new LiNO3-NaNO3-KNO3
ternary salt for thermal energy storage system (in preparation)
[68] G D Carvalho E Frollini and W N D Santos Thermal conductivity of polymers by hot-
wire method J Appl Poly Sci 62 (1996) 2281-2285
[69] H Bloom A Doroszkowski and S B Tricklebank Molten salt mixtures IX The thermal
conductivities of molten nitrate systems Aus J Chem 18(8) (1965) 1171-1176
[70] A G Turnbull Thermal conductivity of molten salts Aus J Appl Sci 12 (1961) 30-41
[71] L R White and H T Davis Thermal conductivity of molten alkali nitrates J Chem Phys
47(1967) 5433-5439
[72] M V Peralta-Martinez M J Assael M J Dix L Karagiannidis and W A Wakeham A
Novel Instrument for the Measurement of the Thermal Conductivity of Molten Metal Part1
Instrument‟s Description Int J Thermophysics 27 (2006) 353-375
[73] Y Tada M Harada M Tanlgakl and W Eguchl Laser Flash Method for Measuring
Thermal Conductivity of Liquids Application to Molten Salts Industrial and Engineering
Chemistry Fundamentals 20 1981 333- 336
[74] M V Smirnov V A Khokhlov and E S Filatov Thermal conductivity of molten alkali
halides and their mixtures Electrochimica Acta 32 (1986) 1019-1026
[75] E Marti E Kaisersberger and W D Emmerich NEW ASPECTS OF THERMAL
ANALYSIS Part I Resolution of DSC and means for its optimization Journal of Thermal
Analysis and Calorimetry 77 2004 905-934
103
[76] E Marti E Kaisersberger G Kaiser and WY Ma Netzsch Annual 2000
bdquoThermoanalytical Characterization of Pharmaceuticals‟ Netzsch-Geraumltebau GmbH D-95100
SelbBavaria
[77] P J van Ekeren C M Holl and A J Witteveen A comparative test of differential
scanning calorimeters Journal of Thermal Analysis and Calorimetry 49 1997 1105-1114
[78] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation
Equations for Critically Evaluated Density Surface Tension Electrical Conductance and
Viscosity Data Journal of Physical and Chemical Reference Data 17 1988 1
[79] G F Petersen W A Ewing and G P Smith ldquoDensities of Some Salt Mixturesrdquo Journal of
Chemical and Engineering Data 6 1961 540
[80] P M Nasch and S G Steinemann Density and Thermal Expansion of Molten Manganese
Iron Nickel Copper Aluminum and Tin by Means of the Gamma-Ray Attenuation Technique
Physics and Chemistry of Liquids 29 1995 43-58
[81] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical and Engineering Data 6 1961 493-496
[82] D A Nissen Thermophysical Properties of the Equimolar Mixture NaNO3-KNO3 from
300degC to 600degC Journal of Chemical and Engineering Data 27 1982 269-273
[83] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate
Mixtures Journal of Chemical and Engineering Data 8 1963 469
104
APPENDIX
Appendix A
Table A1 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in solid state
(29815-40315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 342 1290 417 -025
299 027 008 000 343 1317 426 -026
300 059 018 000 344 1345 436 -027
301 091 028 000 345 1372 445 -028
302 123 037 000 346 1399 455 -029
303 154 047 000 347 1427 464 -031
304 186 056 000 348 1454 474 -032
305 217 066 000 349 1481 483 -033
306 248 076 000 350 1508 493 -035
307 279 085 000 351 1535 503 -036
308 310 095 -001 352 1562 512 -038
309 340 104 -001 353 1589 522 -039
310 371 114 -001 354 1616 532 -041
311 401 123 -001 355 1643 541 -042
312 432 133 -002 356 1670 551 -044
313 462 142 -002 357 1697 561 -045
314 492 152 -002 358 1724 570 -047
315 521 161 -003 359 1751 580 -048
316 551 171 -003 360 1777 590 -050
317 581 180 -004 361 1804 600 -052
318 610 190 -004 362 1831 610 -053
319 640 199 -005 363 1858 619 -055
320 669 209 -005 364 1885 629 -057
105
321 698 218 -006 365 1911 639 -059
322 727 228 -007 366 1938 649 -060
323 756 237 -007 367 1965 659 -062
324 785 246 -008 368 1992 669 -064
325 814 256 -009 369 2018 679 -066
326 842 265 -009 370 2045 689 -068
327 871 275 -010 371 2072 699 -070
328 899 284 -011 372 2098 709 -072
329 928 294 -012 373 2125 719 -074
330 956 303 -012 374 2152 729 -076
331 984 313 -013 375 2179 739 -078
332 1012 322 -014 376 2205 750 -080
333 1041 331 -015 377 2232 760 -082
334 1069 341 -016 378 2259 770 -084
335 1096 350 -017 379 2286 780 -086
336 1124 360 -018 380 2312 791 -088
337 1152 369 -019 381 2339 801 -090
338 1180 379 -020 382 2366 811 -093
339 1207 388 -021 383 2393 822 -095
340 1235 398 -022 384 2420 832 -097
341 1263 407 -023 38415 2424 834 -097
Table A2 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in liquid state
(40315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
40315 4287 1565 -163 514 7070 2838 -796
404 4310 1575 -167 515 7094 2850 -803
405 4337 1585 -171 516 7117 2863 -810
406 4363 1596 -175 517 7141 2875 -817
407 4390 1607 -180 518 7165 2887 -824
408 4417 1618 -184 519 7188 2899 -831
409 4443 1629 -189 520 7212 2911 -839
410 4470 1640 -193 521 7235 2924 -846
411 4496 1651 -197 522 7259 2936 -853
412 4523 1662 -202 523 7282 2948 -860
106
413 4549 1672 -206 524 7306 2960 -868
414 4576 1683 -211 525 7329 2973 -875
415 4602 1694 -216 526 7352 2985 -882
416 4629 1705 -220 527 7376 2997 -890
417 4655 1716 -225 528 7399 3010 -897
418 4681 1727 -230 529 7422 3022 -904
419 4708 1738 -234 530 7446 3034 -912
420 4734 1749 -239 531 7469 3047 -919
421 4760 1760 -244 532 7492 3059 -927
422 4786 1771 -249 533 7516 3071 -934
423 4813 1782 -253 534 7539 3084 -942
424 4839 1793 -258 535 7562 3096 -949
425 4865 1804 -263 536 7585 3109 -957
426 4891 1816 -268 537 7608 3121 -965
427 4917 1827 -273 538 7632 3134 -972
428 4943 1838 -278 539 7655 3146 -980
429 4969 1849 -283 540 7678 3158 -988
430 4995 1860 -288 541 7701 3171 -995
431 5021 1871 -293 542 7724 3183 -1003
432 5046 1882 -298 543 7747 3196 -1011
433 5072 1894 -303 544 7770 3208 -1018
434 5098 1905 -308 545 7793 3221 -1026
435 5124 1916 -313 546 7816 3233 -1034
436 5149 1927 -318 547 7839 3246 -1042
437 5175 1938 -323 548 7862 3259 -1050
438 5201 1950 -328 549 7885 3271 -1058
439 5226 1961 -334 550 7908 3284 -1066
440 5252 1972 -339 551 7931 3296 -1073
441 5278 1983 -344 552 7953 3309 -1081
442 5303 1995 -349 553 7976 3322 -1089
443 5329 2006 -355 554 7999 3334 -1097
444 5354 2017 -360 555 8022 3347 -1105
445 5380 2028 -365 556 8045 3359 -1113
446 5405 2040 -371 557 8067 3372 -1121
447 5430 2051 -376 558 8090 3385 -1130
448 5456 2062 -382 559 8113 3398 -1138
449 5481 2074 -387 560 8136 3410 -1146
450 5506 2085 -393 561 8158 3423 -1154
451 5532 2097 -398 562 8181 3436 -1162
452 5557 2108 -404 563 8204 3448 -1170
107
453 5582 2119 -409 564 8226 3461 -1178
454 5607 2131 -415 565 8249 3474 -1187
455 5633 2142 -421 566 8271 3487 -1195
456 5658 2154 -426 567 8294 3499 -1203
457 5683 2165 -432 568 8317 3512 -1212
458 5708 2177 -438 569 8339 3525 -1220
459 5733 2188 -443 570 8362 3538 -1228
460 5758 2200 -449 571 8384 3551 -1237
461 5783 2211 -455 572 8407 3564 -1245
462 5808 2223 -461 573 8429 3576 -1253
463 5833 2234 -466 574 8452 3589 -1262
464 5858 2246 -472 575 8474 3602 -1270
465 5883 2257 -478 576 8496 3615 -1279
466 5907 2269 -484 577 8519 3628 -1287
467 5932 2280 -490 578 8541 3641 -1296
468 5957 2292 -496 579 8564 3654 -1304
469 5982 2304 -502 580 8586 3667 -1313
470 6007 2315 -508 581 8608 3680 -1322
471 6031 2327 -514 582 8631 3693 -1330
472 6056 2339 -520 583 8653 3706 -1339
473 6081 2350 -526 584 8675 3719 -1348
474 6105 2362 -532 585 8697 3732 -1356
475 6130 2373 -538 586 8720 3745 -1365
476 6155 2385 -544 587 8742 3758 -1374
477 6179 2397 -551 588 8764 3771 -1382
478 6204 2409 -557 589 8786 3784 -1391
479 6228 2420 -563 590 8808 3797 -1400
480 6253 2432 -569 591 8831 3810 -1409
481 6277 2444 -575 592 8853 3823 -1418
482 6301 2456 -582 593 8875 3836 -1426
483 6326 2467 -588 594 8897 3849 -1435
484 6350 2479 -594 595 8919 3863 -1444
485 6375 2491 -601 596 8941 3876 -1453
486 6399 2503 -607 597 8963 3889 -1462
487 6423 2515 -614 598 8985 3902 -1471
488 6448 2526 -620 599 9007 3915 -1480
489 6472 2538 -626 600 9029 3928 -1489
490 6496 2550 -633 601 9051 3942 -1498
491 6520 2562 -639 602 9073 3955 -1507
492 6544 2574 -646 603 9095 3968 -1516
108
493 6569 2586 -653 604 9117 3981 -1525
494 6593 2598 -659 605 9139 3994 -1535
495 6617 2610 -666 606 9161 4008 -1544
496 6641 2621 -672 607 9183 4021 -1553
497 6665 2633 -679 608 9205 4034 -1562
498 6689 2645 -686 609 9226 4048 -1571
499 6713 2657 -692 610 9248 4061 -1581
500 6737 2669 -699 611 9270 4074 -1590
501 6761 2681 -706 612 9292 4088 -1599
502 6785 2693 -713 613 9314 4101 -1608
503 6809 2705 -719 614 9335 4114 -1618
504 6833 2717 -726 615 9357 4128 -1627
505 6856 2729 -733 616 9379 4141 -1636
506 6880 2741 -740 617 9401 4154 -1646
507 6904 2754 -747 618 9422 4168 -1655
508 6928 2766 -754 619 9444 4181 -1665
509 6952 2778 -761 620 9466 4195 -1674
510 6975 2790 -768 621 9487 4208 -1684
511 6999 2802 -775 622 9509 4222 -1693
512 7023 2814 -782 623 9531 4235 -1703
513 7047 2826 -789 62315 9534 4237 -1704
109
Appendix B
Table B1 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(29815-39215K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 347 1233 382 -046
299 022 006 000 348 1258 390 -048
300 049 014 -001 349 1283 398 -049
301 075 022 -001 350 1307 406 -051
302 101 029 -001 351 1332 415 -053
303 127 037 -002 352 1356 423 -054
304 153 044 -002 353 1381 431 -056
305 179 052 -003 354 1405 440 -058
306 205 059 -003 355 1430 448 -060
307 230 067 -004 356 1455 456 -061
308 256 075 -004 357 1479 465 -063
309 282 082 -005 358 1504 473 -065
310 308 090 -005 359 1528 482 -067
311 333 098 -006 360 1553 490 -069
312 359 105 -007 361 1577 498 -071
313 384 113 -007 362 1602 507 -073
314 410 121 -008 363 1626 515 -075
315 435 128 -009 364 1651 524 -077
316 461 136 -010 365 1675 533 -079
317 486 144 -010 366 1700 541 -081
318 511 151 -011 367 1724 550 -083
319 537 159 -012 368 1749 558 -085
320 562 167 -013 369 1773 567 -087
321 587 175 -014 370 1798 576 -089
322 612 182 -015 371 1822 584 -092
323 637 190 -016 372 1847 593 -094
324 663 198 -017 373 1871 602 -096
325 688 206 -018 374 1896 611 -098
326 713 214 -019 375 1920 620 -100
327 738 222 -020 376 1945 628 -103
328 763 229 -021 377 1969 637 -105
329 788 237 -022 378 1994 646 -107
110
330 813 245 -023 379 2018 655 -110
331 838 253 -024 380 2043 664 -112
332 863 261 -025 381 2068 673 -115
333 887 269 -027 382 2092 682 -117
334 912 277 -028 383 2117 691 -120
335 937 285 -029 384 2141 700 -122
336 962 293 -030 385 2166 709 -125
337 987 301 -032 386 2191 718 -127
338 1011 309 -033 387 2215 727 -130
339 1036 317 -034 388 2240 737 -132
340 1061 325 -036 389 2265 746 -135
341 1086 333 -037 390 2289 755 -138
342 1110 341 -039 391 2314 764 -140
343 1135 349 -040 392 2339 774 -143
344 1160 357 -042 39215 2342 775 -144
345 1184 365 -043
Table B2 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(41315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
414 3280 1149 -209 520 5608 2235 -682
415 3302 1158 -212 521 5630 2246 -687
416 3325 1167 -216 522 5651 2257 -693
417 3348 1177 -219 523 5672 2268 -698
418 3370 1186 -223 524 5694 2279 -704
419 3393 1196 -226 525 5715 2290 -710
420 3416 1205 -229 526 5736 2302 -716
421 3438 1215 -233 527 5757 2313 -721
422 3461 1224 -236 528 5779 2324 -727
423 3483 1234 -240 529 5800 2335 -733
424 3506 1243 -243 530 5821 2347 -739
425 3529 1253 -247 531 5842 2358 -745
426 3551 1263 -250 532 5864 2369 -750
427 3574 1272 -254 533 5885 2380 -756
428 3596 1282 -257 534 5906 2392 -762
429 3619 1291 -261 535 5927 2403 -768
111
430 3641 1301 -265 536 5948 2414 -774
431 3663 1311 -268 537 5970 2426 -780
432 3686 1320 -272 538 5991 2437 -786
433 3708 1330 -276 539 6012 2449 -792
434 3731 1340 -279 540 6033 2460 -798
435 3753 1350 -283 541 6054 2471 -804
436 3775 1359 -287 542 6075 2483 -810
437 3798 1369 -291 543 6096 2494 -816
438 3820 1379 -294 544 6118 2506 -822
439 3842 1389 -298 545 6139 2517 -828
440 3865 1398 -302 546 6160 2529 -835
441 3887 1408 -306 547 6181 2540 -841
442 3909 1418 -310 548 6202 2552 -847
443 3932 1428 -314 549 6223 2563 -853
444 3954 1438 -318 550 6244 2575 -859
445 3976 1448 -322 551 6265 2586 -866
446 3998 1458 -326 552 6286 2598 -872
447 4021 1468 -330 553 6307 2610 -878
448 4043 1477 -334 554 6328 2621 -884
449 4065 1487 -338 555 6349 2633 -891
450 4087 1497 -342 556 6370 2645 -897
451 4109 1507 -346 557 6391 2656 -904
452 4131 1517 -350 558 6412 2668 -910
453 4154 1527 -354 559 6433 2680 -916
454 4176 1537 -358 560 6454 2691 -923
455 4198 1547 -363 561 6475 2703 -929
456 4220 1557 -367 562 6496 2715 -936
457 4242 1568 -371 563 6517 2727 -942
458 4264 1578 -375 564 6538 2738 -949
459 4286 1588 -380 565 6559 2750 -955
460 4308 1598 -384 566 6580 2762 -962
461 4330 1608 -388 567 6600 2774 -969
462 4352 1618 -393 568 6621 2786 -975
463 4374 1628 -397 569 6642 2798 -982
464 4396 1639 -401 570 6663 2810 -988
465 4418 1649 -406 571 6684 2821 -995
466 4440 1659 -410 572 6705 2833 -1002
467 4462 1669 -415 573 6726 2845 -1009
468 4484 1680 -419 574 6747 2857 -1015
469 4506 1690 -424 575 6767 2869 -1022
112
470 4528 1700 -428 576 6788 2881 -1029
471 4550 1710 -433 577 6809 2893 -1036
472 4572 1721 -437 578 6830 2905 -1042
473 4593 1731 -442 579 6851 2917 -1049
474 4615 1741 -446 580 6871 2929 -1056
475 4637 1752 -451 581 6892 2941 -1063
476 4659 1762 -456 582 6913 2953 -1070
477 4681 1773 -460 583 6934 2966 -1077
478 4703 1783 -465 584 6954 2978 -1084
479 4724 1793 -470 585 6975 2990 -1091
480 4746 1804 -474 586 6996 3002 -1098
481 4768 1814 -479 587 7017 3014 -1105
482 4790 1825 -484 588 7037 3026 -1112
483 4812 1835 -489 589 7058 3038 -1119
484 4833 1846 -494 590 7079 3051 -1126
485 4855 1856 -498 591 7100 3063 -1133
486 4877 1867 -503 592 7120 3075 -1140
487 4898 1877 -508 593 7141 3087 -1147
488 4920 1888 -513 594 7162 3100 -1154
489 4942 1899 -518 595 7182 3112 -1162
490 4963 1909 -523 596 7203 3124 -1169
491 4985 1920 -528 597 7224 3137 -1176
492 5007 1930 -533 598 7244 3149 -1183
493 5028 1941 -538 599 7265 3161 -1190
494 5050 1952 -543 600 7285 3174 -1198
495 5072 1962 -548 601 7306 3186 -1205
496 5093 1973 -553 602 7327 3198 -1212
497 5115 1984 -558 603 7347 3211 -1220
498 5136 1995 -563 604 7368 3223 -1227
499 5158 2005 -568 605 7389 3236 -1234
500 5180 2016 -574 606 7409 3248 -1242
501 5201 2027 -579 607 7430 3261 -1249
502 5223 2038 -584 608 7450 3273 -1257
503 5244 2049 -589 609 7471 3286 -1264
504 5266 2059 -595 610 7491 3298 -1272
505 5287 2070 -600 611 7512 3311 -1279
506 5309 2081 -605 612 7532 3323 -1287
507 5330 2092 -610 613 7553 3336 -1294
508 5352 2103 -616 614 7573 3348 -1302
509 5373 2114 -621 615 7594 3361 -1309
113
510 5394 2125 -627 616 7615 3374 -1317
511 5416 2136 -632 617 7635 3386 -1325
512 5437 2147 -637 618 7656 3399 -1332
513 5459 2158 -643 619 7676 3412 -1340
514 5480 2169 -648 620 7696 3424 -1348
515 5502 2180 -654 621 7717 3437 -1355
516 5523 2191 -659 622 7737 3450 -1363
517 5544 2202 -665 623 7758 3462 -1371
518 5566 2213 -670 62315 7761 3464 -1372
114
Appendix C
Table C1 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in solid
state (29815-36415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 333 1937 611 -034
299 048 014 000 334 1992 629 -036
300 104 031 000 335 2047 647 -038
301 160 048 000 336 2102 666 -040
302 216 065 000 337 2156 684 -042
303 272 082 -001 338 2211 703 -045
304 329 099 -001 339 2266 721 -047
305 385 116 -001 340 2321 740 -049
306 441 133 -002 341 2375 758 -052
307 496 150 -002 342 2430 777 -054
308 552 167 -003 343 2485 796 -056
309 608 185 -003 344 2539 815 -059
310 664 202 -004 345 2594 833 -062
311 720 219 -005 346 2648 852 -064
312 776 236 -006 347 2703 871 -067
313 831 254 -006 348 2757 890 -070
314 887 271 -007 349 2812 909 -072
315 942 289 -008 350 2866 928 -075
316 998 306 -009 351 2921 947 -078
317 1054 324 -010 352 2975 966 -081
318 1109 341 -011 353 3029 985 -084
319 1164 359 -012 354 3084 1004 -087
320 1220 377 -014 355 3138 1024 -090
321 1275 395 -015 356 3192 1043 -094
322 1331 412 -016 357 3246 1062 -097
323 1386 430 -018 358 3300 1082 -100
324 1441 448 -019 359 3355 1101 -103
325 1496 466 -020 360 3409 1120 -107
326 1552 484 -022 361 3463 1140 -110
327 1607 502 -024 362 3517 1159 -114
328 1662 520 -025 363 3571 1179 -117
329 1717 538 -027 364 3625 1199 -121
115
330 1772 556 -029 36415 3633 1202 -121
331 1827 574 -030
332 1882 593 -032
Table C2 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in liquid
state (42115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
42115 7428 2673 -455 523 11788 4725 -1440
422 7468 2690 -461 524 11827 4745 -1452
423 7515 2710 -468 525 11866 4766 -1464
424 7562 2730 -476 526 11904 4786 -1476
425 7608 2750 -484 527 11943 4807 -1488
426 7655 2770 -491 528 11982 4827 -1500
427 7702 2790 -499 529 12021 4847 -1512
428 7748 2810 -507 530 12059 4868 -1524
429 7795 2830 -514 531 12098 4888 -1536
430 7841 2849 -522 532 12137 4909 -1548
431 7887 2869 -530 533 12175 4929 -1560
432 7933 2889 -538 534 12213 4950 -1572
433 7979 2909 -546 535 12252 4970 -1584
434 8025 2929 -554 536 12290 4991 -1597
435 8071 2949 -562 537 12328 5011 -1609
436 8117 2969 -570 538 12366 5032 -1621
437 8163 2989 -578 539 12404 5052 -1634
438 8208 3009 -586 540 12442 5073 -1646
439 8254 3029 -595 541 12480 5093 -1659
440 8299 3049 -603 542 12518 5114 -1671
441 8345 3069 -611 543 12556 5134 -1684
442 8390 3089 -620 544 12594 5155 -1696
443 8435 3109 -628 545 12632 5175 -1709
444 8480 3129 -636 546 12669 5196 -1721
445 8525 3149 -645 547 12707 5217 -1734
446 8570 3169 -654 548 12745 5237 -1747
116
447 8615 3189 -662 549 12782 5258 -1760
448 8659 3209 -671 550 12820 5278 -1772
449 8704 3229 -679 551 12857 5299 -1785
450 8748 3249 -688 552 12894 5319 -1798
451 8793 3269 -697 553 12932 5340 -1811
452 8837 3289 -706 554 12969 5361 -1824
453 8881 3309 -715 555 13006 5381 -1837
454 8926 3329 -724 556 13043 5402 -1850
455 8970 3349 -732 557 13080 5422 -1863
456 9014 3369 -741 558 13117 5443 -1876
457 9058 3389 -750 559 13154 5464 -1889
458 9102 3409 -760 560 13191 5484 -1902
459 9145 3429 -769 561 13228 5505 -1916
460 9189 3449 -778 562 13264 5526 -1929
461 9233 3469 -787 563 13301 5546 -1942
462 9276 3489 -796 564 13338 5567 -1956
463 9319 3509 -806 565 13374 5588 -1969
464 9363 3529 -815 566 13411 5608 -1982
465 9406 3549 -824 567 13447 5629 -1996
466 9449 3570 -834 568 13484 5650 -2009
467 9492 3590 -843 569 13520 5670 -2023
468 9535 3610 -853 570 13557 5691 -2036
469 9578 3630 -862 571 13593 5712 -2050
470 9621 3650 -872 572 13629 5732 -2063
471 9664 3670 -882 573 13665 5753 -2077
472 9707 3690 -891 574 13701 5774 -2091
473 9749 3710 -901 575 13737 5795 -2104
474 9792 3731 -911 576 13773 5815 -2118
475 9834 3751 -921 577 13809 5836 -2132
476 9877 3771 -930 578 13845 5857 -2146
477 9919 3791 -940 579 13881 5877 -2160
478 9961 3811 -950 580 13917 5898 -2174
479 10004 3831 -960 581 13953 5919 -2188
480 10046 3852 -970 582 13988 5940 -2202
481 10088 3872 -980 583 14024 5960 -2216
482 10130 3892 -990 584 14060 5981 -2230
483 10171 3912 -1001 585 14095 6002 -2244
484 10213 3932 -1011 586 14131 6023 -2258
485 10255 3953 -1021 587 14166 6044 -2272
486 10297 3973 -1031 588 14201 6064 -2286
117
487 10338 3993 -1042 589 14237 6085 -2300
488 10380 4013 -1052 590 14272 6106 -2315
489 10421 4034 -1062 591 14307 6127 -2329
490 10462 4054 -1073 592 14342 6148 -2343
491 10504 4074 -1083 593 14378 6168 -2358
492 10545 4094 -1094 594 14413 6189 -2372
493 10586 4114 -1104 595 14448 6210 -2386
494 10627 4135 -1115 596 14483 6231 -2401
495 10668 4155 -1126 597 14518 6252 -2415
496 10709 4175 -1136 598 14552 6273 -2430
497 10750 4196 -1147 599 14587 6293 -2444
498 10791 4216 -1158 600 14622 6314 -2459
499 10831 4236 -1169 601 14657 6335 -2474
500 10872 4256 -1179 602 14692 6356 -2488
501 10912 4277 -1190 603 14726 6377 -2503
502 10953 4297 -1201 604 14761 6398 -2518
503 10993 4317 -1212 605 14795 6419 -2533
504 11034 4338 -1223 606 14830 6439 -2547
505 11074 4358 -1234 607 14864 6460 -2562
506 11114 4378 -1245 608 14899 6481 -2577
507 11154 4399 -1257 609 14933 6502 -2592
508 11194 4419 -1268 610 14967 6523 -2607
509 11234 4439 -1279 611 15002 6544 -2622
510 11274 4460 -1290 612 15036 6565 -2637
511 11314 4480 -1302 613 15070 6586 -2652
512 11354 4500 -1313 614 15104 6607 -2667
513 11394 4521 -1324 615 15138 6628 -2682
514 11433 4541 -1336 616 15172 6649 -2697
515 11473 4562 -1347 617 15206 6670 -2713
516 11513 4582 -1359 618 15240 6691 -2728
517 11552 4602 -1370 619 15274 6712 -2743
518 11591 4623 -1382 620 15308 6733 -2758
519 11631 4643 -1393 621 15342 6754 -2774
520 11670 4664 -1405 622 15375 6774 -2789
521 11709 4684 -1417 623 15409 6795 -2804
522 11748 4704 -1428 62315 15414 6799 -2807
118
Appendix D
Table D1 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in solid state
(29815-36315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
299 021 006 000 333 867 277 -012
300 047 014 000 334 891 285 -012
301 072 022 000 335 916 293 -013
302 097 029 000 336 940 302 -014
303 122 037 000 337 964 310 -015
304 147 045 000 338 989 318 -016
305 172 053 000 339 1013 327 -017
306 197 060 000 340 1037 335 -018
307 223 068 000 341 1061 343 -019
308 248 076 000 342 1085 352 -019
309 273 084 000 343 1109 360 -020
310 298 092 -001 344 1134 369 -021
311 323 099 -001 345 1158 377 -022
312 348 107 -001 346 1182 385 -024
313 373 115 -001 347 1206 394 -025
314 398 123 -002 348 1230 402 -026
315 423 131 -002 349 1254 411 -027
316 447 139 -002 350 1277 419 -028
317 472 147 -003 351 1301 428 -029
318 497 155 -003 352 1325 436 -030
319 522 163 -003 353 1349 445 -032
320 547 171 -004 354 1373 453 -033
321 572 179 -004 355 1396 462 -034
322 596 187 -005 356 1420 470 -035
323 621 195 -005 357 1444 479 -037
324 646 203 -006 358 1467 487 -038
325 670 211 -006 359 1491 496 -039
326 695 220 -007 360 1514 504 -041
327 720 228 -008 361 1538 513 -042
328 744 236 -008 362 1561 522 -043
329 769 244 -009 363 1584 530 -045
330 793 252 -010 36315 1588 532 -045
119
331 818 260 -010
Table D2 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in liquid
state (38115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
38115 2281 765 -104 503 5639 2242 -594
382 2307 775 -106 504 5664 2255 -600
383 2338 787 -109 505 5689 2267 -606
384 2369 798 -111 506 5713 2280 -611
385 2399 810 -113 507 5738 2292 -617
386 2430 822 -116 508 5763 2305 -623
387 2460 834 -118 509 5787 2317 -629
388 2491 846 -121 510 5812 2330 -634
389 2521 857 -123 511 5836 2342 -640
390 2551 869 -126 512 5861 2355 -646
391 2582 881 -128 513 5885 2367 -652
392 2612 893 -131 514 5910 2380 -658
393 2642 905 -134 515 5934 2392 -664
394 2672 917 -136 516 5959 2405 -670
395 2702 928 -139 517 5983 2417 -676
396 2732 940 -142 518 6007 2430 -682
397 2762 952 -144 519 6032 2443 -688
398 2792 964 -147 520 6056 2455 -694
399 2821 976 -150 521 6080 2468 -700
400 2851 988 -153 522 6104 2480 -706
401 2881 999 -156 523 6128 2493 -712
402 2910 1011 -159 524 6152 2506 -718
403 2940 1023 -162 525 6176 2518 -724
404 2969 1035 -164 526 6200 2531 -731
405 2999 1047 -167 527 6224 2544 -737
406 3028 1059 -170 528 6248 2556 -743
407 3057 1071 -174 529 6272 2569 -749
408 3087 1083 -177 530 6296 2581 -756
120
409 3116 1095 -180 531 6320 2594 -762
410 3145 1107 -183 532 6344 2607 -768
411 3174 1119 -186 533 6368 2619 -775
412 3203 1130 -189 534 6391 2632 -781
413 3232 1142 -192 535 6415 2645 -787
414 3261 1154 -196 536 6439 2657 -794
415 3290 1166 -199 537 6462 2670 -800
416 3319 1178 -202 538 6486 2683 -807
417 3347 1190 -206 539 6510 2696 -813
418 3376 1202 -209 540 6533 2708 -820
419 3405 1214 -212 541 6557 2721 -826
420 3433 1226 -216 542 6580 2734 -833
421 3462 1238 -219 543 6604 2746 -839
422 3490 1250 -223 544 6627 2759 -846
423 3519 1262 -226 545 6650 2772 -853
424 3547 1274 -230 546 6674 2785 -859
425 3575 1286 -233 547 6697 2797 -866
426 3604 1298 -237 548 6720 2810 -873
427 3632 1310 -240 549 6744 2823 -879
428 3660 1322 -244 550 6767 2836 -886
429 3688 1334 -248 551 6790 2848 -893
430 3716 1346 -251 552 6813 2861 -900
431 3744 1358 -255 553 6836 2874 -907
432 3772 1371 -259 554 6860 2887 -913
433 3800 1383 -263 555 6883 2900 -920
434 3828 1395 -267 556 6906 2912 -927
435 3856 1407 -270 557 6929 2925 -934
436 3883 1419 -274 558 6952 2938 -941
437 3911 1431 -278 559 6975 2951 -948
438 3939 1443 -282 560 6998 2964 -955
439 3966 1455 -286 561 7020 2976 -962
440 3994 1467 -290 562 7043 2989 -969
441 4021 1479 -294 563 7066 3002 -976
442 4049 1491 -298 564 7089 3015 -983
443 4076 1504 -302 565 7112 3028 -990
444 4103 1516 -306 566 7134 3041 -997
445 4131 1528 -310 567 7157 3054 -1005
446 4158 1540 -314 568 7180 3066 -1012
447 4185 1552 -319 569 7203 3079 -1019
448 4212 1564 -323 570 7225 3092 -1026
121
449 4240 1576 -327 571 7248 3105 -1033
450 4267 1589 -331 572 7270 3118 -1041
451 4294 1601 -336 573 7293 3131 -1048
452 4321 1613 -340 574 7315 3144 -1055
453 4347 1625 -344 575 7338 3157 -1063
454 4374 1637 -349 576 7360 3170 -1070
455 4401 1650 -353 577 7383 3183 -1077
456 4428 1662 -357 578 7405 3196 -1085
457 4455 1674 -362 579 7428 3208 -1092
458 4481 1686 -366 580 7450 3221 -1100
459 4508 1698 -371 581 7472 3234 -1107
460 4535 1711 -375 582 7494 3247 -1114
461 4561 1723 -380 583 7517 3260 -1122
462 4588 1735 -384 584 7539 3273 -1129
463 4614 1747 -389 585 7561 3286 -1137
464 4641 1760 -394 586 7583 3299 -1145
465 4667 1772 -398 587 7605 3312 -1152
466 4693 1784 -403 588 7628 3325 -1160
467 4720 1796 -408 589 7650 3338 -1167
468 4746 1809 -412 590 7672 3351 -1175
469 4772 1821 -417 591 7694 3364 -1183
470 4798 1833 -422 592 7716 3377 -1191
471 4825 1846 -427 593 7738 3390 -1198
472 4851 1858 -432 594 7760 3403 -1206
473 4877 1870 -437 595 7782 3416 -1214
474 4903 1882 -441 596 7804 3429 -1222
475 4929 1895 -446 597 7825 3442 -1229
476 4955 1907 -451 598 7847 3455 -1237
477 4980 1919 -456 599 7869 3469 -1245
478 5006 1932 -461 600 7891 3482 -1253
479 5032 1944 -466 601 7913 3495 -1261
480 5058 1956 -471 602 7934 3508 -1269
481 5083 1969 -476 603 7956 3521 -1277
482 5109 1981 -481 604 7978 3534 -1285
483 5135 1994 -487 605 8000 3547 -1293
484 5160 2006 -492 606 8021 3560 -1301
485 5186 2018 -497 607 8043 3573 -1309
486 5211 2031 -502 608 8064 3586 -1317
487 5237 2043 -507 609 8086 3599 -1325
488 5262 2055 -513 610 8107 3613 -1333
122
489 5288 2068 -518 611 8129 3626 -1341
490 5313 2080 -523 612 8150 3639 -1349
491 5338 2093 -528 613 8172 3652 -1357
492 5364 2105 -534 614 8193 3665 -1366
493 5389 2117 -539 615 8215 3678 -1374
494 5414 2130 -545 616 8236 3692 -1382
495 5439 2142 -550 617 8258 3705 -1390
496 5464 2155 -555 618 8279 3718 -1398
497 5489 2167 -561 619 8300 3731 -1407
498 5514 2180 -566 620 8321 3744 -1415
499 5539 2192 -572 621 8343 3757 -1423
500 5564 2205 -578 622 8364 3771 -1432
501 5589 2217 -583 623 8385 3784 -1441
502 5614 2230 -589 62315 8388 3786 -1443
123
Appendix E
Table E1 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in solid state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 913 287 -014
299 025 007 000 331 941 296 -015
300 054 016 000 332 970 306 -016
301 083 025 000 333 998 315 -017
302 112 034 000 334 1026 324 -018
303 141 042 000 335 1054 334 -019
304 170 051 000 336 1081 343 -020
305 199 060 -001 337 1109 353 -021
306 228 069 -001 338 1137 362 -022
307 257 078 -001 339 1165 371 -024
308 286 087 -001 340 1193 381 -025
309 315 096 -002 341 1221 390 -026
310 343 105 -002 342 1248 400 -027
311 372 113 -002 343 1276 409 -028
312 401 122 -003 344 1304 419 -030
313 430 131 -003 345 1331 428 -031
314 458 140 -003 346 1359 438 -032
315 487 149 -004 347 1386 447 -034
316 516 159 -004 348 1414 457 -035
317 544 168 -005 349 1441 466 -036
318 573 177 -006 350 1468 476 -038
319 602 186 -006 351 1496 486 -039
320 630 195 -007 352 1523 495 -041
321 659 204 -007 353 1550 505 -042
322 687 213 -008 354 1577 514 -044
323 715 222 -009 355 1605 524 -046
324 744 232 -009 356 1632 534 -047
325 772 241 -010 357 1659 543 -049
326 800 250 -011 358 1686 553 -050
327 829 259 -012 359 1713 563 -052
328 857 269 -013 35915 1717 564 -052
329 885 278 -013
124
Table E2 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in liquid state (376-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2323 777 -094 500 5525 2173 -590
376 2347 786 -096 501 5548 2184 -595
377 2375 797 -098 502 5572 2196 -601
378 2403 808 -101 503 5595 2208 -606
379 2431 818 -103 504 5619 2220 -612
380 2459 829 -106 505 5642 2232 -618
381 2487 839 -108 506 5665 2243 -623
382 2515 850 -111 507 5689 2255 -629
383 2542 861 -113 508 5712 2267 -635
384 2570 871 -116 509 5735 2279 -640
385 2598 882 -118 510 5759 2291 -646
386 2626 893 -121 511 5782 2303 -652
387 2653 903 -123 512 5805 2315 -658
388 2681 914 -126 513 5828 2326 -664
389 2708 925 -129 514 5852 2338 -669
390 2736 935 -132 515 5875 2350 -675
391 2763 946 -134 516 5898 2362 -681
392 2791 957 -137 517 5921 2374 -687
393 2818 968 -140 518 5944 2386 -693
394 2845 978 -143 519 5967 2398 -699
395 2873 989 -146 520 5990 2410 -705
396 2900 1000 -148 521 6013 2422 -711
397 2927 1011 -151 522 6036 2434 -717
398 2954 1022 -154 523 6059 2446 -723
399 2981 1032 -157 524 6082 2458 -729
400 3008 1043 -160 525 6105 2470 -735
401 3035 1054 -163 526 6128 2482 -741
402 3062 1065 -166 527 6151 2494 -747
403 3089 1076 -169 528 6173 2506 -754
404 3116 1086 -172 529 6196 2518 -760
405 3143 1097 -176 530 6219 2530 -766
125
406 3170 1108 -179 531 6242 2542 -772
407 3197 1119 -182 532 6265 2554 -778
408 3223 1130 -185 533 6287 2566 -785
409 3250 1141 -188 534 6310 2578 -791
410 3277 1152 -192 535 6333 2591 -797
411 3303 1163 -195 536 6355 2603 -804
412 3330 1174 -198 537 6378 2615 -810
413 3356 1185 -202 538 6400 2627 -816
414 3383 1195 -205 539 6423 2639 -823
415 3409 1206 -208 540 6445 2651 -829
416 3436 1217 -212 541 6468 2663 -836
417 3462 1228 -215 542 6490 2676 -842
418 3488 1239 -219 543 6513 2688 -849
419 3515 1250 -222 544 6535 2700 -855
420 3541 1261 -226 545 6558 2712 -862
421 3567 1272 -229 546 6580 2724 -868
422 3593 1283 -233 547 6602 2737 -875
423 3619 1294 -236 548 6625 2749 -882
424 3645 1305 -240 549 6647 2761 -888
425 3671 1317 -244 550 6669 2773 -895
426 3697 1328 -247 551 6692 2786 -902
427 3723 1339 -251 552 6714 2798 -908
428 3749 1350 -255 553 6736 2810 -915
429 3775 1361 -259 554 6758 2822 -922
430 3801 1372 -262 555 6780 2835 -929
431 3827 1383 -266 556 6803 2847 -935
432 3852 1394 -270 557 6825 2859 -942
433 3878 1405 -274 558 6847 2872 -949
434 3904 1416 -278 559 6869 2884 -956
435 3929 1428 -282 560 6891 2896 -963
436 3955 1439 -286 561 6913 2909 -970
437 3981 1450 -290 562 6935 2921 -977
438 4006 1461 -294 563 6957 2933 -983
439 4032 1472 -298 564 6979 2946 -990
440 4057 1483 -302 565 7001 2958 -997
441 4083 1495 -306 566 7023 2971 -1004
442 4108 1506 -310 567 7045 2983 -1011
443 4133 1517 -314 568 7067 2995 -1019
444 4159 1528 -318 569 7089 3008 -1026
445 4184 1540 -322 570 7110 3020 -1033
126
446 4209 1551 -327 571 7132 3033 -1040
447 4234 1562 -331 572 7154 3045 -1047
448 4260 1573 -335 573 7176 3058 -1054
449 4285 1585 -339 574 7198 3070 -1061
450 4310 1596 -344 575 7219 3083 -1069
451 4335 1607 -348 576 7241 3095 -1076
452 4360 1618 -352 577 7263 3108 -1083
453 4385 1630 -357 578 7284 3120 -1090
454 4410 1641 -361 579 7306 3133 -1098
455 4435 1652 -365 580 7328 3145 -1105
456 4460 1664 -370 581 7349 3158 -1112
457 4485 1675 -374 582 7371 3170 -1120
458 4510 1687 -379 583 7393 3183 -1127
459 4534 1698 -383 584 7414 3195 -1134
460 4559 1709 -388 585 7436 3208 -1142
461 4584 1721 -393 586 7457 3221 -1149
462 4609 1732 -397 587 7479 3233 -1157
463 4633 1743 -402 588 7500 3246 -1164
464 4658 1755 -406 589 7522 3258 -1172
465 4683 1766 -411 590 7543 3271 -1179
466 4707 1778 -416 591 7564 3284 -1187
467 4732 1789 -420 592 7586 3296 -1194
468 4756 1801 -425 593 7607 3309 -1202
469 4781 1812 -430 594 7628 3322 -1210
470 4805 1824 -435 595 7650 3334 -1217
471 4830 1835 -440 596 7671 3347 -1225
472 4854 1847 -444 597 7692 3360 -1233
473 4878 1858 -449 598 7714 3373 -1240
474 4903 1870 -454 599 7735 3385 -1248
475 4927 1881 -459 600 7756 3398 -1256
476 4951 1893 -464 601 7777 3411 -1264
477 4975 1904 -469 602 7799 3423 -1271
478 5000 1916 -474 603 7820 3436 -1279
479 5024 1927 -479 604 7841 3449 -1287
480 5048 1939 -484 605 7862 3462 -1295
481 5072 1951 -489 606 7883 3475 -1303
482 5096 1962 -494 607 7904 3487 -1311
483 5120 1974 -499 608 7925 3500 -1318
484 5144 1985 -504 609 7946 3513 -1326
485 5168 1997 -510 610 7967 3526 -1334
127
486 5192 2009 -515 611 7988 3539 -1342
487 5216 2020 -520 612 8009 3551 -1350
488 5240 2032 -525 613 8030 3564 -1358
489 5264 2044 -530 614 8051 3577 -1366
490 5288 2055 -536 615 8072 3590 -1374
491 5312 2067 -541 616 8093 3603 -1383
492 5335 2079 -546 617 8114 3616 -1391
493 5359 2090 -552 618 8135 3629 -1399
494 5383 2102 -557 619 8156 3642 -1407
495 5407 2114 -562 620 8177 3655 -1415
496 5430 2126 -568 621 8198 3667 -1423
497 5454 2137 -573 622 8219 3680 -1431
498 5478 2149 -579 623 8239 3693 -1440
499 5501 2161 -584 62315 8242 3695 -1441
128
Appendix F
Table F1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in solid
state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 1063 334 -017
299 029 009 000 331 1096 345 -018
300 063 019 000 332 1128 356 -019
301 097 029 000 333 1161 366 -020
302 131 039 000 334 1193 377 -021
303 165 050 000 335 1225 388 -022
304 199 060 -001 336 1258 399 -024
305 233 070 -001 337 1290 410 -025
306 267 081 -001 338 1322 421 -026
307 300 091 -001 339 1355 432 -028
308 334 101 -002 340 1387 443 -029
309 368 112 -002 341 1419 454 -030
310 401 122 -002 342 1451 464 -032
311 435 133 -003 343 1483 475 -033
312 468 143 -003 344 1515 486 -035
313 502 153 -004 345 1547 497 -036
314 535 164 -004 346 1578 508 -038
315 569 174 -005 347 1610 519 -039
316 602 185 -005 348 1642 531 -041
317 635 196 -006 349 1674 542 -043
318 668 206 -006 350 1705 553 -044
319 702 217 -007 351 1737 564 -046
320 735 227 -008 352 1769 575 -048
321 768 238 -009 353 1800 586 -049
322 801 248 -009 354 1832 597 -051
323 834 259 -010 355 1863 608 -053
324 867 270 -011 356 1894 619 -055
325 900 280 -012 357 1926 631 -057
326 932 291 -013 358 1957 642 -059
327 965 302 -014 359 1988 653 -061
328 998 313 -015 35915 1993 655 -061
329 1030 323 -016
129
Table F2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in liquid
state (37515-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2691 926 -083 500 6111 2416 -640
376 2717 936 -085 501 6136 2428 -646
377 2747 948 -088 502 6161 2440 -652
378 2778 959 -091 503 6185 2453 -658
379 2808 971 -094 504 6210 2465 -665
380 2838 982 -096 505 6235 2478 -671
381 2869 994 -099 506 6259 2490 -677
382 2899 1005 -102 507 6284 2502 -683
383 2929 1017 -105 508 6308 2515 -690
384 2959 1028 -108 509 6333 2527 -696
385 2989 1040 -111 510 6357 2540 -702
386 3019 1051 -114 511 6381 2552 -709
387 3049 1063 -117 512 6406 2565 -715
388 3079 1075 -120 513 6430 2577 -721
389 3109 1086 -123 514 6454 2590 -728
390 3138 1098 -126 515 6479 2602 -734
391 3168 1109 -129 516 6503 2615 -741
392 3198 1121 -133 517 6527 2627 -747
393 3227 1132 -136 518 6551 2640 -754
394 3257 1144 -139 519 6575 2652 -760
395 3286 1156 -142 520 6599 2665 -767
396 3316 1167 -146 521 6624 2677 -774
397 3345 1179 -149 522 6648 2690 -780
398 3374 1191 -152 523 6672 2702 -787
399 3403 1202 -156 524 6696 2715 -794
400 3433 1214 -159 525 6719 2727 -800
401 3462 1226 -163 526 6743 2740 -807
402 3491 1237 -166 527 6767 2753 -814
403 3520 1249 -170 528 6791 2765 -821
404 3549 1261 -173 529 6815 2778 -827
405 3578 1272 -177 530 6839 2790 -834
130
406 3606 1284 -180 531 6862 2803 -841
407 3635 1296 -184 532 6886 2815 -848
408 3664 1307 -187 533 6910 2828 -855
409 3693 1319 -191 534 6933 2841 -862
410 3721 1331 -195 535 6957 2853 -869
411 3750 1343 -199 536 6981 2866 -876
412 3778 1354 -202 537 7004 2879 -883
413 3807 1366 -206 538 7028 2891 -890
414 3835 1378 -210 539 7051 2904 -897
415 3864 1390 -214 540 7075 2917 -904
416 3892 1401 -218 541 7098 2929 -911
417 3920 1413 -222 542 7122 2942 -918
418 3948 1425 -226 543 7145 2955 -925
419 3977 1437 -230 544 7168 2967 -932
420 4005 1449 -234 545 7192 2980 -939
421 4033 1460 -238 546 7215 2993 -947
422 4061 1472 -242 547 7238 3005 -954
423 4089 1484 -246 548 7261 3018 -961
424 4117 1496 -250 549 7285 3031 -968
425 4145 1508 -254 550 7308 3044 -976
426 4172 1519 -258 551 7331 3056 -983
427 4200 1531 -262 552 7354 3069 -990
428 4228 1543 -266 553 7377 3082 -998
429 4256 1555 -271 554 7400 3095 -1005
430 4283 1567 -275 555 7423 3107 -1013
431 4311 1579 -279 556 7446 3120 -1020
432 4338 1591 -284 557 7469 3133 -1027
433 4366 1603 -288 558 7492 3146 -1035
434 4393 1614 -292 559 7515 3159 -1042
435 4421 1626 -297 560 7538 3171 -1050
436 4448 1638 -301 561 7561 3184 -1058
437 4475 1650 -306 562 7584 3197 -1065
438 4503 1662 -310 563 7607 3210 -1073
439 4530 1674 -315 564 7629 3223 -1080
440 4557 1686 -319 565 7652 3235 -1088
441 4584 1698 -324 566 7675 3248 -1096
442 4611 1710 -328 567 7697 3261 -1103
443 4638 1722 -333 568 7720 3274 -1111
444 4665 1734 -338 569 7743 3287 -1119
445 4692 1746 -342 570 7765 3300 -1126
131
446 4719 1758 -347 571 7788 3313 -1134
447 4746 1770 -352 572 7811 3326 -1142
448 4773 1782 -356 573 7833 3338 -1150
449 4800 1794 -361 574 7856 3351 -1158
450 4826 1806 -366 575 7878 3364 -1166
451 4853 1818 -371 576 7901 3377 -1173
452 4880 1830 -376 577 7923 3390 -1181
453 4906 1842 -381 578 7945 3403 -1189
454 4933 1854 -386 579 7968 3416 -1197
455 4959 1866 -391 580 7990 3429 -1205
456 4986 1878 -396 581 8012 3442 -1213
457 5012 1890 -401 582 8035 3455 -1221
458 5039 1902 -406 583 8057 3468 -1229
459 5065 1914 -411 584 8079 3481 -1237
460 5091 1926 -416 585 8101 3494 -1245
461 5118 1938 -421 586 8124 3507 -1254
462 5144 1951 -426 587 8146 3520 -1262
463 5170 1963 -431 588 8168 3533 -1270
464 5196 1975 -436 589 8190 3546 -1278
465 5222 1987 -441 590 8212 3559 -1286
466 5248 1999 -447 591 8234 3572 -1294
467 5274 2011 -452 592 8256 3585 -1303
468 5300 2023 -457 593 8278 3598 -1311
469 5326 2035 -463 594 8300 3611 -1319
470 5352 2048 -468 595 8322 3624 -1328
471 5378 2060 -473 596 8344 3637 -1336
472 5404 2072 -479 597 8366 3650 -1344
473 5430 2084 -484 598 8388 3663 -1353
474 5455 2096 -490 599 8410 3676 -1361
475 5481 2108 -495 600 8432 3690 -1369
476 5507 2121 -500 601 8454 3703 -1378
477 5532 2133 -506 602 8475 3716 -1386
478 5558 2145 -512 603 8497 3729 -1395
479 5583 2157 -517 604 8519 3742 -1403
480 5609 2170 -523 605 8541 3755 -1412
481 5634 2182 -528 606 8562 3768 -1420
482 5660 2194 -534 607 8584 3781 -1429
483 5685 2206 -540 608 8606 3795 -1438
484 5710 2219 -545 609 8627 3808 -1446
485 5736 2231 -551 610 8649 3821 -1455
132
486 5761 2243 -557 611 8670 3834 -1464
487 5786 2255 -563 612 8692 3847 -1472
488 5812 2268 -568 613 8713 3860 -1481
489 5837 2280 -574 614 8735 3874 -1490
490 5862 2292 -580 615 8756 3887 -1498
491 5887 2305 -586 616 8778 3900 -1507
492 5912 2317 -592 617 8799 3913 -1516
493 5937 2329 -598 618 8821 3926 -1525
494 5962 2342 -604 619 8842 3940 -1534
495 5987 2354 -610 620 8864 3953 -1542
496 6012 2366 -616 621 8885 3966 -1551
497 6037 2379 -622 622 8906 3979 -1560
498 6062 2391 -628 623 8928 3993 -1569
499 6086 2403 -634 62315 8931 3995 -1570
133
Appendix G
Table G1 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid I state (29815-33715K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 319 578 162 -004
299 024 000 000 320 606 170 -005
300 052 000 000 321 633 179 -005
301 080 007 000 322 660 188 -006
302 108 016 000 323 688 197 -007
303 136 024 000 324 715 205 -007
304 164 032 000 325 742 214 -008
305 192 041 000 326 769 223 -009
306 219 049 000 327 796 232 -009
307 247 058 000 328 823 241 -010
308 275 067 -001 329 851 250 -011
309 303 075 -001 330 878 259 -011
310 330 084 -001 331 905 268 -012
311 358 092 -001 332 932 277 -013
312 386 101 -002 333 959 285 -014
313 413 109 -002 334 985 294 -015
314 441 118 -002 335 1012 303 -016
315 468 127 -003 336 1039 312 -017
316 496 135 -003 337 1066 321 -018
317 523 144 -003 33715 1070 331 -019
318 551 153 -004
Table G2 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid II state (36115-36415K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36115 2433 825 -054
134
362 2454 832 -056
363 2478 841 -059
364 2503 850 -061
36415 2506 851 -062
Table G3 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
liquid state (41115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
41115 3833 1366 -210 518 6604 2649 -772
412 3857 1376 -213 519 6628 2661 -778
413 3885 1387 -217 520 6652 2674 -785
414 3913 1399 -221 521 6675 2686 -792
415 3941 1411 -225 522 6699 2699 -798
416 3969 1422 -229 523 6723 2711 -805
417 3997 1434 -233 524 6747 2723 -812
418 4025 1446 -237 525 6770 2736 -819
419 4053 1457 -241 526 6794 2748 -825
420 4081 1469 -245 527 6818 2761 -832
421 4109 1481 -249 528 6841 2773 -839
422 4137 1493 -253 529 6865 2786 -846
423 4165 1504 -257 530 6888 2798 -853
424 4192 1516 -262 531 6912 2810 -860
425 4220 1528 -266 532 6935 2823 -867
426 4248 1539 -270 533 6959 2835 -873
427 4275 1551 -274 534 6982 2848 -880
428 4303 1563 -279 535 7005 2860 -887
429 4330 1575 -283 536 7029 2873 -894
430 4358 1587 -287 537 7052 2885 -902
431 4385 1598 -292 538 7075 2898 -909
432 4412 1610 -296 539 7098 2910 -916
433 4439 1622 -300 540 7122 2923 -923
434 4467 1634 -305 541 7145 2935 -930
135
435 4494 1646 -309 542 7168 2948 -937
436 4521 1657 -314 543 7191 2960 -944
437 4548 1669 -318 544 7214 2973 -951
438 4575 1681 -323 545 7237 2986 -959
439 4602 1693 -328 546 7260 2998 -966
440 4629 1705 -332 547 7283 3011 -973
441 4656 1716 -337 548 7306 3023 -980
442 4683 1728 -341 549 7329 3036 -988
443 4710 1740 -346 550 7352 3048 -995
444 4736 1752 -351 551 7375 3061 -1003
445 4763 1764 -356 552 7398 3074 -1010
446 4790 1776 -360 553 7420 3086 -1017
447 4816 1788 -365 554 7443 3099 -1025
448 4843 1800 -370 555 7466 3111 -1032
449 4869 1812 -375 556 7489 3124 -1040
450 4896 1823 -380 557 7511 3137 -1047
451 4922 1835 -385 558 7534 3149 -1055
452 4949 1847 -390 559 7557 3162 -1062
453 4975 1859 -395 560 7579 3175 -1070
454 5002 1871 -400 561 7602 3187 -1077
455 5028 1883 -405 562 7625 3200 -1085
456 5054 1895 -410 563 7647 3213 -1093
457 5080 1907 -415 564 7670 3225 -1100
458 5106 1919 -420 565 7692 3238 -1108
459 5132 1931 -425 566 7714 3251 -1116
460 5159 1943 -430 567 7737 3263 -1123
461 5185 1955 -435 568 7759 3276 -1131
462 5211 1967 -440 569 7782 3289 -1139
463 5236 1979 -446 570 7804 3302 -1147
464 5262 1991 -451 571 7826 3314 -1155
465 5288 2003 -456 572 7849 3327 -1162
466 5314 2015 -461 573 7871 3340 -1170
467 5340 2027 -467 574 7893 3352 -1178
468 5366 2039 -472 575 7915 3365 -1186
469 5391 2051 -478 576 7937 3378 -1194
470 5417 2063 -483 577 7960 3391 -1202
471 5442 2075 -488 578 7982 3404 -1210
472 5468 2087 -494 579 8004 3416 -1218
473 5494 2099 -499 580 8026 3429 -1226
474 5519 2111 -505 581 8048 3442 -1234
136
475 5545 2123 -510 582 8070 3455 -1242
476 5570 2135 -516 583 8092 3468 -1250
477 5595 2147 -521 584 8114 3480 -1258
478 5621 2160 -527 585 8136 3493 -1266
479 5646 2172 -533 586 8158 3506 -1274
480 5671 2184 -538 587 8180 3519 -1283
481 5696 2196 -544 588 8201 3532 -1291
482 5722 2208 -550 589 8223 3545 -1299
483 5747 2220 -555 590 8245 3557 -1307
484 5772 2232 -561 591 8267 3570 -1315
485 5797 2244 -567 592 8289 3583 -1324
486 5822 2257 -573 593 8310 3596 -1332
487 5847 2269 -579 594 8332 3609 -1340
488 5872 2281 -585 595 8354 3622 -1349
489 5897 2293 -590 596 8375 3635 -1357
490 5922 2305 -596 597 8397 3648 -1365
491 5947 2317 -602 598 8419 3660 -1374
492 5971 2330 -608 599 8440 3673 -1382
493 5996 2342 -614 600 8462 3686 -1391
494 6021 2354 -620 601 8483 3699 -1399
495 6046 2366 -626 602 8505 3712 -1408
496 6070 2379 -632 603 8526 3725 -1416
497 6095 2391 -638 604 8548 3738 -1425
498 6119 2403 -645 605 8569 3751 -1433
499 6144 2415 -651 606 8591 3764 -1442
500 6169 2427 -657 607 8612 3777 -1451
501 6193 2440 -663 608 8633 3790 -1459
502 6217 2452 -669 609 8655 3803 -1468
503 6242 2464 -675 610 8676 3816 -1476
504 6266 2477 -682 611 8697 3829 -1485
505 6291 2489 -688 612 8719 3842 -1494
506 6315 2501 -694 613 8740 3855 -1503
507 6339 2513 -701 614 8761 3868 -1511
508 6363 2526 -707 615 8782 3881 -1520
509 6388 2538 -713 616 8803 3894 -1529
510 6412 2550 -720 617 8825 3907 -1538
511 6436 2563 -726 618 8846 3920 -1547
512 6460 2575 -733 619 8867 3933 -1555
513 6484 2587 -739 620 8888 3946 -1564
514 6508 2600 -746 621 8909 3959 -1573
137
515 6532 2612 -752 622 8930 3972 -1582
516 6556 2624 -759 623 8951 3985 -1591
517 6580 2637 -765 62315 8954 3987 -1592
138
Appendix H
Table H1 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid I
state (29815-35415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 768 241 -011
299 023 007 000 328 794 249 -011
300 050 015 000 329 820 258 -012
301 077 023 000 330 846 266 -013
302 104 031 000 331 872 275 -014
303 131 039 000 332 898 284 -015
304 158 048 000 333 924 292 -016
305 185 056 -001 334 950 301 -016
306 212 064 -001 335 976 310 -017
307 239 072 -001 336 1002 318 -018
308 265 081 -001 337 1028 327 -019
309 292 089 -001 338 1053 336 -020
310 319 097 -002 339 1079 344 -021
311 345 105 -002 340 1105 353 -022
312 372 114 -002 341 1130 362 -024
313 399 122 -003 342 1156 371 -025
314 425 130 -003 343 1182 379 -026
315 452 139 -004 344 1207 388 -027
316 478 147 -004 345 1233 397 -028
317 505 156 -004 346 1258 406 -029
318 531 164 -005 347 1284 415 -031
319 558 172 -005 348 1309 424 -032
320 584 181 -006 349 1335 433 -033
321 611 189 -007 350 1360 441 -035
322 637 198 -007 351 1385 450 -036
323 663 206 -008 352 1411 459 -037
324 689 215 -008 353 1436 468 -039
325 716 223 -009 354 1461 477 -040
326 742 232 -010 35415 1465 478 -040
139
Table H2 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid 2
state (36215-37315K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36215 2387 777 -046
363 2408 809 -055
364 2432 817 -057
365 2457 826 -060
366 2481 835 -062
367 2506 843 -065
368 2530 852 -067
369 2555 861 -070
370 2579 870 -072
371 2604 879 -075
372 2628 888 -077
373 2653 898 -080
37315 2657 907 -083
Table H3 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in liquid
state (37915-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37915 2966 1025 -100 502 6174 2432 -667
380 2991 1034 -102 503 6198 2444 -674
381 3020 1045 -105 504 6222 2456 -680
382 3048 1056 -108 505 6246 2468 -686
383 3077 1067 -112 506 6270 2480 -692
384 3105 1078 -115 507 6294 2492 -699
385 3134 1089 -118 508 6317 2504 -705
386 3162 1100 -121 509 6341 2516 -711
387 3191 1111 -124 510 6365 2528 -718
140
388 3219 1122 -127 511 6388 2541 -724
389 3247 1133 -130 512 6412 2553 -730
390 3275 1144 -134 513 6436 2565 -737
391 3304 1155 -137 514 6459 2577 -743
392 3332 1166 -140 515 6483 2589 -750
393 3360 1177 -144 516 6506 2601 -756
394 3388 1188 -147 517 6530 2613 -763
395 3416 1199 -150 518 6553 2625 -769
396 3444 1210 -154 519 6577 2638 -776
397 3472 1221 -157 520 6600 2650 -782
398 3500 1232 -161 521 6624 2662 -789
399 3527 1243 -164 522 6647 2674 -796
400 3555 1254 -168 523 6670 2686 -802
401 3583 1265 -171 524 6694 2698 -809
402 3611 1276 -175 525 6717 2711 -816
403 3638 1287 -179 526 6740 2723 -822
404 3666 1299 -182 527 6763 2735 -829
405 3693 1310 -186 528 6786 2747 -836
406 3721 1321 -190 529 6810 2760 -843
407 3748 1332 -193 530 6833 2772 -850
408 3776 1343 -197 531 6856 2784 -856
409 3803 1354 -201 532 6879 2796 -863
410 3830 1366 -205 533 6902 2809 -870
411 3857 1377 -209 534 6925 2821 -877
412 3885 1388 -213 535 6948 2833 -884
413 3912 1399 -216 536 6971 2845 -891
414 3939 1410 -220 537 6994 2858 -898
415 3966 1422 -224 538 7017 2870 -905
416 3993 1433 -228 539 7040 2882 -912
417 4020 1444 -232 540 7063 2895 -919
418 4047 1455 -236 541 7086 2907 -926
419 4074 1467 -240 542 7108 2919 -933
420 4101 1478 -245 543 7131 2932 -940
421 4128 1489 -249 544 7154 2944 -947
422 4154 1500 -253 545 7177 2957 -955
423 4181 1512 -257 546 7199 2969 -962
424 4208 1523 -261 547 7222 2981 -969
425 4234 1534 -265 548 7245 2994 -976
426 4261 1546 -270 549 7267 3006 -984
427 4288 1557 -274 550 7290 3019 -991
141
428 4314 1568 -278 551 7313 3031 -998
429 4341 1580 -282 552 7335 3044 -1005
430 4367 1591 -287 553 7358 3056 -1013
431 4393 1602 -291 554 7380 3068 -1020
432 4420 1614 -296 555 7403 3081 -1028
433 4446 1625 -300 556 7425 3093 -1035
434 4472 1636 -305 557 7448 3106 -1042
435 4499 1648 -309 558 7470 3118 -1050
436 4525 1659 -314 559 7492 3131 -1057
437 4551 1671 -318 560 7515 3143 -1065
438 4577 1682 -323 561 7537 3156 -1072
439 4603 1694 -327 562 7560 3169 -1080
440 4629 1705 -332 563 7582 3181 -1087
441 4655 1716 -336 564 7604 3194 -1095
442 4681 1728 -341 565 7626 3206 -1103
443 4707 1739 -346 566 7649 3219 -1110
444 4733 1751 -351 567 7671 3231 -1118
445 4759 1762 -355 568 7693 3244 -1126
446 4785 1774 -360 569 7715 3257 -1133
447 4810 1785 -365 570 7737 3269 -1141
448 4836 1797 -370 571 7759 3282 -1149
449 4862 1808 -375 572 7782 3294 -1157
450 4888 1820 -379 573 7804 3307 -1164
451 4913 1832 -384 574 7826 3320 -1172
452 4939 1843 -389 575 7848 3332 -1180
453 4964 1855 -394 576 7870 3345 -1188
454 4990 1866 -399 577 7892 3358 -1196
455 5015 1878 -404 578 7914 3370 -1204
456 5041 1889 -409 579 7936 3383 -1212
457 5066 1901 -414 580 7957 3396 -1220
458 5092 1913 -419 581 7979 3408 -1228
459 5117 1924 -424 582 8001 3421 -1236
460 5142 1936 -430 583 8023 3434 -1244
461 5167 1947 -435 584 8045 3447 -1252
462 5193 1959 -440 585 8067 3459 -1260
463 5218 1971 -445 586 8088 3472 -1268
464 5243 1982 -450 587 8110 3485 -1276
465 5268 1994 -456 588 8132 3498 -1284
466 5293 2006 -461 589 8154 3510 -1292
467 5318 2017 -466 590 8175 3523 -1300
142
468 5343 2029 -472 591 8197 3536 -1308
469 5368 2041 -477 592 8219 3549 -1317
470 5393 2053 -482 593 8240 3562 -1325
471 5418 2064 -488 594 8262 3574 -1333
472 5443 2076 -493 595 8283 3587 -1341
473 5468 2088 -499 596 8305 3600 -1350
474 5493 2100 -504 597 8327 3613 -1358
475 5517 2111 -510 598 8348 3626 -1366
476 5542 2123 -515 599 8370 3639 -1375
477 5567 2135 -521 600 8391 3652 -1383
478 5592 2147 -526 601 8413 3664 -1391
479 5616 2158 -532 602 8434 3677 -1400
480 5641 2170 -537 603 8455 3690 -1408
481 5665 2182 -543 604 8477 3703 -1417
482 5690 2194 -549 605 8498 3716 -1425
483 5715 2206 -554 606 8520 3729 -1434
484 5739 2218 -560 607 8541 3742 -1442
485 5763 2229 -566 608 8562 3755 -1451
486 5788 2241 -572 609 8583 3768 -1459
487 5812 2253 -578 610 8605 3781 -1468
488 5837 2265 -583 611 8626 3794 -1477
489 5861 2277 -589 612 8647 3807 -1485
490 5885 2289 -595 613 8668 3820 -1494
491 5910 2301 -601 614 8690 3833 -1503
492 5934 2313 -607 615 8711 3846 -1511
493 5958 2324 -613 616 8732 3859 -1520
494 5982 2336 -619 617 8753 3872 -1529
495 6006 2348 -625 618 8774 3885 -1538
496 6030 2360 -631 619 8795 3898 -1546
497 6055 2372 -637 620 8816 3911 -1555
498 6079 2384 -643 621 8837 3924 -1564
499 6103 2396 -649 622 8858 3937 -1573
500 6127 2408 -655 623 8879 3950 -1582
501 6151 2420 -661 62315 8883 3952 -1583
143
Appendix I
Table I1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in solid state (29815-35315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 1171 366 -017
299 035 010 000 328 1211 379 -018
300 076 023 000 329 1250 392 -019
301 117 035 000 330 1290 405 -021
302 158 048 000 331 1330 418 -022
303 199 060 000 332 1369 431 -023
304 240 072 -001 333 1409 444 -025
305 281 085 -001 334 1448 458 -026
306 322 097 -001 335 1488 471 -028
307 363 110 -002 336 1527 484 -029
308 404 122 -002 337 1566 497 -031
309 445 135 -002 338 1605 510 -032
310 486 148 -003 339 1644 524 -034
311 526 160 -003 340 1683 537 -036
312 567 173 -004 341 1722 550 -037
313 608 186 -005 342 1761 563 -039
314 648 198 -005 343 1800 577 -041
315 689 211 -006 344 1839 590 -043
316 729 224 -007 345 1877 603 -044
317 770 237 -007 346 1916 617 -046
318 810 250 -008 347 1955 630 -048
319 850 262 -009 348 1993 643 -050
320 891 275 -010 349 2031 657 -052
321 931 288 -011 350 2070 670 -054
322 971 301 -012 351 2108 683 -056
323 1011 314 -013 352 2146 697 -059
324 1051 327 -014 353 2184 710 -061
325 1091 340 -015 35315 2190 712 -061
326 1131 353 -016
144
Table I2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in liquid state (39115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
39115 4413 1056 -191 508 8890 3521 -978
392 4450 1535 -195 509 8924 3538 -986
393 4492 1549 -200 510 8959 3556 -995
394 4535 1566 -204 511 8993 3574 -1004
395 4577 1583 -209 512 9027 3591 -1013
396 4620 1599 -213 513 9062 3609 -1022
397 4662 1616 -218 514 9096 3626 -1031
398 4704 1633 -223 515 9130 3644 -1041
399 4746 1650 -227 516 9164 3661 -1050
400 4789 1666 -232 517 9198 3679 -1059
401 4831 1683 -237 518 9232 3697 -1068
402 4872 1700 -242 519 9266 3714 -1077
403 4914 1717 -247 520 9300 3732 -1087
404 4956 1734 -252 521 9334 3750 -1096
405 4997 1751 -257 522 9368 3767 -1105
406 5039 1767 -262 523 9402 3785 -1115
407 5080 1784 -267 524 9435 3802 -1124
408 5122 1801 -272 525 9469 3820 -1134
409 5163 1818 -277 526 9503 3838 -1143
410 5204 1835 -282 527 9536 3855 -1152
411 5245 1852 -287 528 9570 3873 -1162
412 5286 1869 -293 529 9603 3891 -1172
413 5327 1885 -298 530 9637 3908 -1181
414 5368 1902 -303 531 9670 3926 -1191
415 5409 1919 -309 532 9703 3944 -1201
416 5450 1936 -314 533 9737 3962 -1210
417 5490 1953 -320 534 9770 3979 -1220
418 5531 1970 -325 535 9803 3997 -1230
419 5571 1987 -331 536 9836 4015 -1240
420 5612 2004 -336 537 9869 4032 -1249
421 5652 2021 -342 538 9902 4050 -1259
145
422 5692 2038 -347 539 9935 4068 -1269
423 5732 2055 -353 540 9968 4086 -1279
424 5772 2072 -359 541 10001 4104 -1289
425 5812 2089 -365 542 10034 4121 -1299
426 5852 2106 -371 543 10066 4139 -1309
427 5892 2123 -376 544 10099 4157 -1319
428 5932 2140 -382 545 10132 4175 -1329
429 5971 2157 -388 546 10165 4192 -1340
430 6011 2174 -394 547 10197 4210 -1350
431 6051 2191 -400 548 10230 4228 -1360
432 6090 2208 -406 549 10262 4246 -1370
433 6129 2225 -412 550 10295 4264 -1380
434 6169 2242 -419 551 10327 4282 -1391
435 6208 2259 -425 552 10359 4299 -1401
436 6247 2276 -431 553 10392 4317 -1411
437 6286 2293 -437 554 10424 4335 -1422
438 6325 2310 -444 555 10456 4353 -1432
439 6364 2327 -450 556 10488 4371 -1443
440 6403 2344 -456 557 10520 4389 -1453
441 6442 2361 -463 558 10553 4407 -1464
442 6480 2378 -469 559 10585 4424 -1474
443 6519 2395 -476 560 10617 4442 -1485
444 6557 2412 -482 561 10648 4460 -1496
445 6596 2429 -489 562 10680 4478 -1506
446 6634 2446 -495 563 10712 4496 -1517
447 6673 2464 -502 564 10744 4514 -1528
448 6711 2481 -509 565 10776 4532 -1538
449 6749 2498 -515 566 10808 4550 -1549
450 6787 2515 -522 567 10839 4568 -1560
451 6825 2532 -529 568 10871 4586 -1571
452 6863 2549 -536 569 10902 4604 -1582
453 6901 2566 -543 570 10934 4622 -1593
454 6939 2584 -550 571 10965 4640 -1604
455 6977 2601 -557 572 10997 4658 -1615
456 7015 2618 -564 573 11028 4676 -1626
457 7052 2635 -571 574 11060 4694 -1637
458 7090 2652 -578 575 11091 4712 -1648
459 7128 2670 -585 576 11122 4730 -1659
460 7165 2687 -592 577 11154 4748 -1670
461 7202 2704 -599 578 11185 4766 -1681
146
462 7240 2721 -606 579 11216 4784 -1692
463 7277 2738 -614 580 11247 4802 -1704
464 7314 2756 -621 581 11278 4820 -1715
465 7351 2773 -628 582 11309 4838 -1726
466 7388 2790 -636 583 11340 4856 -1737
467 7425 2807 -643 584 11371 4874 -1749
468 7462 2825 -650 585 11402 4892 -1760
469 7499 2842 -658 586 11433 4910 -1772
470 7536 2859 -665 587 11464 4928 -1783
471 7573 2877 -673 588 11495 4946 -1794
472 7609 2894 -680 589 11525 4964 -1806
473 7646 2911 -688 590 11556 4982 -1817
474 7682 2928 -696 591 11587 5001 -1829
475 7719 2946 -703 592 11617 5019 -1841
476 7755 2963 -711 593 11648 5037 -1852
477 7792 2980 -719 594 11678 5055 -1864
478 7828 2998 -727 595 11709 5073 -1876
479 7864 3015 -735 596 11739 5091 -1887
480 7900 3032 -742 597 11770 5109 -1899
481 7937 3050 -750 598 11800 5128 -1911
482 7973 3067 -758 599 11831 5146 -1923
483 8009 3084 -766 600 11861 5164 -1935
484 8045 3102 -774 601 11891 5182 -1946
485 8080 3119 -782 602 11921 5200 -1958
486 8116 3137 -791 603 11952 5218 -1970
487 8152 3154 -799 604 11982 5237 -1982
488 8188 3171 -807 605 12012 5255 -1994
489 8223 3189 -815 606 12042 5273 -2006
490 8259 3206 -823 607 12072 5291 -2018
491 8294 3224 -832 608 12102 5309 -2030
492 8330 3241 -840 609 12132 5328 -2042
493 8365 3259 -848 610 12162 5346 -2055
494 8401 3276 -857 611 12192 5364 -2067
495 8436 3293 -865 612 12222 5382 -2079
496 8471 3311 -873 613 12252 5401 -2091
497 8506 3328 -882 614 12281 5419 -2103
498 8542 3346 -890 615 12311 5437 -2116
499 8577 3363 -899 616 12341 5456 -2128
500 8612 3381 -908 617 12370 5474 -2140
501 8647 3398 -916 618 12400 5492 -2153
147
502 8681 3416 -925 619 12430 5510 -2165
503 8716 3433 -934 620 12459 5529 -2178
504 8751 3451 -942 621 12489 5547 -2190
505 8786 3468 -951 622 12518 5565 -2203
506 8820 3486 -960 623 12548 5584 -2215
507 8855 3503 -969 62315 12552 5602 -2217
Copyright Tao Wang 2011
ALL RIGHTS RESERVED
ii
ABSTRACT
New alkali nitrate-nitrite systems were developed by using thermodynamic modeling and
the eutectic points were predicted based on the change of Gibbs energy of fusion Those systems
with melting point lower than 130oC were selected for further analysis The new compounds
were synthesized and the melting point and heat capacity were determined using Differential
Scanning Calorimetry (DSC) The experimentally determined melting points agree well with the
predicted results of modeling It was found that the lithium nitrate amount and heating rate have
significant effects on the melting point value and the endothermic peaks Heat capacity data as a
function of temperature are fit to polynomial equation and thermodynamic properties like
enthalpies entropies and Gibbs energies of the systems as function of temperature are
subsequently induced The densities for the selected systems were experimentally determined
and found in a very close range due to the similar composition In liquid state the density values
decrease linearly as temperature increases with small slope Moreover addition of lithium nitrate
generally decreases the density On the basis of density heat capacity and the melting point
thermal energy storage was calculated Among all the new molten salt systems LiNO3-NaNO3-
KNO3-Mg(NO3)2-MgKN quinary system presents the largest thermal energy storage density as
well as the gravimetric density values Compared to the KNO3-NaNO3 binary solar salt all the
new molten salts present larger thermal energy storage as well as the gravimetric storage density
values which indicate the better thermal energy storage capacity for solar power generation
systems
iii
DEDICATION
This thesis is dedicated to everyone who helped me and guided me through the trials and
tribulations of creating this manuscript In particular my family and close friends who stood by
me throughout the time taken to complete this masterpiece
iv
ACKNOWLEDGEMENTS
I am pleased to express my gratitude and appreciation to my advisor Professor Ramana
G Reddy for his patience and guidance during my graduate study and the entire research work I
am greatly benefited from his experience knowledge and enthusiasm for scientific research
I would like to express my sincere thanks to Dr Nitin Chopra and Dr Yang-Ki Hong for
serving on my committee Their valuable suggestions and comments are very insightful for my
research work
I would like to thank all the research colleagues of Dr Reddy‟s research group special
thanks to Dr Divakar Mantha for his valuable suggestions and comments I would like to extend
my gratitude to US Department of Energy for the financial support
Finally I would like to thank my parents and my fianceacutee whose invaluable
understanding and loving support helped me through the difficult times
v
TABLE OF CONTENTS
ABSTRACT ii
DEDICATION iii
ACKNOWLEDGEMENTS iv
LIST OF TABLES viii
LIST OF FIGURES x
CHAPTER 1 INTRODUCTION 1
CHAPTER 2 LITERATURE REVIEW 11
21 Melting point 11
22 Density 15
23 Heat capacity 18
CHAPTER 3 OBJECTIVES 22
CHAPTER 4 THERMODYNAMIC MODELING OF SALT SYSTEMS 24
41 Thermodynamic modeling 24
42 Calculations 27
vi
CHAPTER 5 EXPERIMENTAL PROCEDURE 30
51 Melting point determination of molten salt mixtures 30
511 Materials 30
512 Apparatus and Procedure 30
52 Heat Capacity determination of molten salt mixtures 32
53 Density determination of molten salt mixtures 33
CHAPTER 6 RESULT AND DISCUSSION 34
61 Melting point determination 34
611 DSC equipment calibration 34
612 Results 35
613 Discussion 41
62 Heat capacity determination 51
621 Heat capacity calibration 51
622 Results 52
623 Thermodynamic properties 55
624 Discussion of Gibbs energy change for molten salts 84
63 Density determination 86
vii
631 Density calibration 86
632 Results and discussions 82
64 Thermal energy storage density of molten salts 90
CHAPTER 7 CONCLUSION 94
REFERENCES 96
APPENDIX 104
APPENDIX A 104
APPENDIX B 109
APPENDIX C 114
APPENDIX D 118
APPENDIX E 123
APPENDIX F 128
APPENDIX G 133
APPENDIX H 138
APPENDIX I 143
viii
LIST OF TABLES
21 Melting point of various nitrate salt systems 12
22 Melting point of various carbonate salt systems 13
23 Melting point of various fluoridechloride salt systems 14
24 Melting point of various hydroixde salt systems 15
25 Density coefficients A and B of nitrate salts 16
26 Density coefficients A and B of carbonate salts 17
27 Density coefficients A and B of chloridefluoride salts 17
28 Density coefficients A and B of molten salt mixture with hydroxide salts 18
29 Heat capacity of alkali nitrate salt at 500oC 19
210 Heat capacity of alkali carbonate salt at 500oC 19
211 Heat capacity of fluoridechloride salt at 500oC 20
212 Heat capacity of hydroxide salt at 500oC 21
41 Calculated composition and melting point for multi-component systems 29
61 Calibration data of melting points with different samples 35
62 DSC results of melting point transition point and change of enthalpy 41
ix
63 Fusion and solid phase transition temperature for individual salts 42
64 Melting points of candidate systems as function of temperatures 51
65 Calibration data of heat capacities with different samples 52
66 Heat capacity of selected new TES molten salt mixtures 54
67 Change of Gibbs energy values at 62315K for molten salt systems 85
68 Calibration of density measurements with different pure nitrate salts 86
69 Coefficient of A and B for density determination of salt 1 to salt 9 87
610 Extrapolated value of density and heat capacity at 500oC of salt 1 to salt 9 91
611 Energy density of salt 1 to salt 9 compare to solar salt 92
612 Gravimetric storage densities for solar salt and new molten salts 93
x
LIST OF FIGURES
11 Theoretical and engineering energy conversion efficiency as function of temperature 6
12 Gravimetric storage density for different energy storage systems
as function of temperature 8
51 Photography of set-up for DSC equipment 31
61 Melting point calibration with indium sample 34
62 Melting point calibration with KNO3 sample 35
63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt 36
64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt 37
65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt 37
66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt 38
67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt 38
68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt 39
69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt 39
610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt 40
611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN Salt 40
612 DSC plot of 698wt KNO3 -302wt NaNO2 binary system 43
xi
613 DSC plot of 270wt NaNO3-730wt KNO3 binary system 45
614 DSC plot of 458wtLiNO3-542wtKNO3 binary system 45
615 DSC plot of 460wt NaNO3-540wt KNO3 binary system 46
616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 20oCmin heating rate 47
616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 5oCmin heating rate 48
617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 5oCmin heating rate 49
617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 20oCmin heating rate 49
618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system
as function of temperature 53
619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K 54
620 Change of Gibbs energy as function of temperature for molten salt systems 85
621 The densities of the salt 1 to salt 5 as function of temperature 87
622 The densities of the salt 6 to salt 9 as function of temperature 89
623 Densities of the salt 1 salt 2 as function of temperature compared to
the equimolar NaNO3-KNO3 binary system and pure KNO3 90
624 Gravimetric storage density comparison of different energy storage
xii
systems as function of temperature 93
1
CHAPTER 1
INTRODUCTION
Renewable energy sources such as wind solar water power geothermal and biomass are
playing more and more significant role in our energy supply Because the cheap cost and infinite
amount of energy storage inside the resource solar energy is emphasized since 20th
century and
viewed as promising alternative method to satisfy the large energy consumption every day in the
world reduce the emission of carbon and strengthen the economy
The wind energy was used as a clean energy to generate electricity back to late 19th
century
However this renewable energy source was not emphasized due to the cheap price of fossil fuel
The re-emergence happened in mid 1950s when the amount of traditional energy source was
found apparently decrease The development of wind energy usage continued and in 1990 the
first mega-watt wind turbine was launched which was viewed as a symbol of shift to large scale
wind energy utilization [1-2] The modern application of wind energy mainly relies on wind
turbine On the basis of aerodynamic wind turbine generates certain net positive torque on
rotating shaft and then converts the mechanical power to electrical power As an electrical power
generator wind turbine is connected to some electrical network to transport the electricity to
battery charging utilities residential power systems and large scale energy consuming systems
In general most of wind turbines are small scale and can only generate 10KW electrical power
Only few of the wind turbine systems operate with capacity as large as 5MW Although the
usage of wind energy can reduce the emission of carbon oxide the noise pollution and high cost
2
limit its large scale application Since the wind is not transportable the electrical energy can only
be generated where the wind blows which also decrease the flexibility of wind energy
Water power is another term of alternative power supply and it was used for irrigation
operating machines like watermill even before the development of electrical power The modern
application of water power is to generate electricity by using the gravitational force of falling or
flowing water These days there are various ways for the water power application The most
traditional method is to store the water in dam and generate electricity by converting the
potential energy pump storage is a different way to utilize water power and can change its
output depending on the energy demand by moving water between reservoirs at different
elevations In the low energy demand period excess energy is used to lift water to the higher
level while in the peak period of energy demand the water is released back to the lower
elevation through water turbine Water power can also be converted by taking advantage of
naturally raise and fall of tide to satisfy the demand of electrical energy consumption [3]
Although the usage of water power can reduce the emission of carbon dioxide and cost it will
destroy the ecosystem because of the large land required for construction There will be methane
emission from the reservoir the potential failure hazard of dam is also a fatal issue and flow
shortage caused by drought may also create serious problem As result of that water power
technique is not a long-term alternative choice
Geothermal energy is the energy form generated inside the earth At the very beginning of
the planet formation a large amount of thermal energy was stored from the radioactive decay of
minerals volcanic activity and solar energy absorption Because of the temperature difference
3
between the core and the surface of planet the thermal energy stored inside the earth is driven to
the outer surface in the form of heat This form of renewable energy source can be applied to
generate electrical power and heat for industrial space and agricultural applications
Theoretically the deposited amount of geothermal energy is adequate to supply the energy
consumption in the world However most of the geothermal energy is stored deeply near the
core of the earth the deep drilling and exploration of geothermal energy is very expensive and
limits the large-scale use of this renewable energy source [4]
Biomass is a renewable energy source used to generate heat or electricity with living or
recently living organism such as wood waste (hydrogen) gas and alcohol fuels The biomass
energy can be converted to electrical energy by thermal method such as combustion pyrolysis
and gasification Several specific chemical processes may also be able to convert the biomass
energy to other forms The main problem arise from application of biomass is air pollution which
contains carbon monoxide NOx (nitrogen oxides) VOCs (volatile organic compounds)
particulates and other pollutants And the level of air pollution to some extent is even above that
of traditional fuel resource Some other possible issue like transportation and sink of carbon also
limit the wide usage of this type of alternative energy [5]
Among all the renewable energy sources solar energy is the most suitable alternative
energy for our future life It is clean cheap abundant without any noise air pollution no
transportation issue and easy to be obtained anywhere in the earth Inside the core of the Sun
hydrogen fuses into helium with a rate of 7times1011
kgs and generates very powerful nucleation
power This type of nucleation explosion creates ultra high temperature in the core of the Sun
4
which reaches approximately 16 million K degrees Although the Sun is not perfectly black body
it still radiates abundant power with the energy density as 16times107 wattsm
2 [6-7] Because of the
enough amount of hydrogen underneath the surface of the Sun the radiation given arise of from
the nucleation explosion can continue at least 5 million years with the same rate and strength
The energy reaching the earth is vastly reduced mainly caused by the absorption and spreading
of the radiation It is easily to understand that there are numerous amorphous objects all around
the entire universe which can absorb certain portion of the radiation for the Sun Moreover the
light generated from the spherical object such as the Sun fills all the available space between the
origin to the destination Even though the energy will not be lost in the travelling process due to
the long distance between the Sun to the earth the surface area of the sphere which is formed
with the Sun as center and the distance as radius is much larger than that of the earth As the
result of that only 1340Wm2 finally reaches the upmost surface of the earth Even though the
final amount of the received solar energy is very small compared to that is initially radiated from
the Sun the average daily solar radiation falling on one area in the continental United States is
equivalent in total energy content to 11 barrels of oil In summary the solar energy itself is
relatively unlimited useful clean and almost unexploited energy and definitely can behave as
the promising mean for the future energy supply [8]
There are several different methods to take advantage of the solar energy and all the
methods can be distinguished into three group solar parabolic trough solar tower and solar dish
Parabolic trough is constructed by silver coated parabolic mirror and there is a Dewar tube going
through the length of the mirror and set on the focal point all the radiation is concentrated on the
tube and transfer by heat transfer fluid to the thermal energy storage unit Solar tower are used to
5
capture solar energy with thousands of mirrors and focus the concentrated sunlight to the top of
the tower which is located in the middle of the heliostats The thermal energy storage medium
within the tower was heated to high temperature and transferred to thermal energy storage tank
and eventually sent to steam pump The solar dish is built with a large reflective parabolic dish
which concentrates all the received sunlight to one spot There is normally a receiver located on
the focal point and transform the solar energy to other forms of useful energy The working
upper limit temperature of solar parabolic trough system is the lowest among these three systems
normally its maximum working temperature is within the range from 400-500oC the solar tower
has higher maximum working temperature which ranges from 500-1000oC the solar dish has the
highest working upper limit temperature which reaches 700-1200oC [9]
The energy conversion efficiency is the most concerned parameter in the solar energy
storage application and the theoretical and real engineering efficiency are given in fig 11 as
function of temperature The theoretical conversion efficiency can be up to 80 while in real
application the value is always less than 70 regardless of collectors The actual efficiency
increases with temperature in the whole working temperature As a result of that the thermal
energy storage materials in solar parabolic trough for instance should be able to work stably at
the upper limit temperature of this type of collection system which is 500oC to ensure the highest
efficiency [9 10]
6
Fig 11 Theoretical and engineering energy conversion efficiency as function of
temperature
Solar energy can be stored in three major forms sensible heat latent heat and
thermochemical heat Sensible heat storage was utilized based on the heat capacity and the
change as function of temperature of storage materials in the charging and discharging process
which correspond to the absorbing and withdrawing energy processes respectively The sensible
heat stored from the melting point to the maximum working temperature can be expressed by
equation 1 [9]
[1]
Where m is the mass of storage material Tmp and TH are melting point temperature and high
temperature in the same phase respectively Cp(T) is the heat capacity at different temperature
Because the sensible heat storage materials remain in a single phase in the working temperature
range the charging and discharging processes are completely reversible for unlimited cycles
7
Latent heat storage is operated by absorbing and withdrawing energy in the charging and
discharging processes accompanied with fusion of materials [9] The latent heat collected
throughout the working temperature range can be expressed by equation 2 as following
[2]
Where T is temperature in solid state Tmp is melting point temperature of storage material TH is
the high temperature in liquid state and is enthalpy of fusion
Thermochemical heat storage is based on the heat capacity and its change as function of
temperature accompanied with chemical reaction The thermochemical heat collected throughout
the working temperature range can be expressed by equation 3
[3]
Where TL is the low temperature before the reaction TR is the reaction temperature and
is the enthalpy of chemical reaction Because of the destruction of the chemical bonds
in the reaction process the charging and discharging process cannot be completely reversible
which reduces the stability and recyclability of storage operation [10]
Sensible energy storage method is chosen to ensure the efficient usage of solar energy for
parabolic trough system of which the maximum working temperature ranges from 400-500oC
Different from thermochemical heat storage the sensible heat storage can achieve completely
reversible working condition under unlimited cycles Also fig 12 illustrates that the sensible
heat storage materials mainly work in the working temperature range for parabolic trough system
8
and the gravimetric energy storage densities of sensible heat is higher than that of latent heat
materials [9 -11]
Fig 12 Gravimetric storage density for different energy storage systems as function of
temperature
Various materials are chosen to serve as thermal energy storage fluid for sensible heat
such as water thermal oil ionic liquid and molten salt [12] The properties of different heat
transfer fluid determine the performance of solar energy heating system In these days the
efficiency and cost of output of electrical power mainly relies on the parabolic trough solar
power plant and the thermal storage fluid [12] A large investment cost is needed to dispatch
100MW to 200MW energy by consuming the energy transfer fluids Given by this situation the
development of new thermal storage fluid with higher thermal energy storage density is
paramount to lower the expense for generating energy and a lot of effect has been put on design
of new systems [13-16]
9
Water is commonly used as heat transfer and thermal energy storage fluid in industry
because of its low cost high heat capacity and high thermal conductivity However the
limitation for using this medium is also obvious that the temperature range within which the
liquid state can be assured is too small It is well know that water can only serve as thermal
energy storage liquid above the freezing point 0oC and below the boiling temperature 100
oC In
practical experiment the actual temperature range is even less than 100oC because of the large
amount of weight loss near the boiling temperature due to the high vapor pressure Water is
possible to work above 100oC only if high pressure is also applied to avoid the phase
transformation but the cost will be highly increased Accordingly water is only suitable to work
in low temperature below 100oC
Thermal oils are also being used in the parabolic trough solar power plant and have very
low melting point as low as 12oC [17 18] However the application of the oil for the thermal
energy storage liquid is limited by some disadvantages from the physic-chemical properties The
upper limit for this oil is only 300oC and above that the liquid state cannot be maintained
Moreover the low thermal decomposition temperature low density and low heat capacity result
in limited thermal energy storage capacity Since the working temperature range is so narrow the
rankie cycle efficiency is reduced when using the synthetic oil and the cost for generating power
is considered to be very expensive [19 20]
Ionic liquid is another medium served as thermal energy storage fluid The liquid
temperature range of ionic liquid is large which is one of the main advantages of this type of
material The high heat capacity and density ensure the efficiency of thermal energy storage of
10
ionic liquid What‟s more the excellent chemical stability and little vapor pressure increase the
lifetime [21-24] However as a result of the very serve corrosion problem to the liquid container
and the high cost the usage of ionic liquid is still limited
Considering various relative physic-chemical properties of thermal energy storage system
molten salts have been proposed as a suitable group for a wide temperature range application
They are being emphasized in the solar energy applications because of their low melting point
and high upper limit which can increase the stable working range The high heat capacity
increases the thermal energy storage density of the heat storage system excellent thermal
stability and negligible vapor pressure ensure the steadiness of cyclic repeating in the lifetime
[25] low viscosity strengths the mobility and efficiency of the thermal storage liquid low
utilization cost reduce the investment and protect the economy The liquidus temperature range
of the molten salt varies from 150-600oC combination of various salts can bring the melting
down and further increase the working temperature range Due to these properties molten salts
can be excellent thermal energy storage fluid in the solar power generation system
11
CHAPTER 2
LITERATURE REVIEW
Several physical and thermodynamic properties of thermal energy storage fluid play
significant role in determining the efficiency and performance of solar energy storage systems In
order to evaluate the feasibility of systems the physic-chemical properties of several molten salts
should be reviewed The three determining parameter which directly affect the thermal energy
storage capacity in systems are melting point heat capacity and density
There are large amount of melting point data available in the literature for various molten
salt system in previous literatures while those with melting point less than 120oC is very limited
All the previous study on molten salt system revealed that five group of molten salts are
emphasized and commonly used alkai or alkaline nitrates carbonates sulphates chloride and
hydroxides Although most of the systems have the same group of cation the melting point
varies a lot from one to anther due to the different effect of anions
21 Melting point
The melting points of individual and multi-component nitratenitrite systems are listed in
Table 21[26-31] Among those systems solar salt (NaNO3KNO3 6040) is the thermal energy
storage medium which is currently being used with the freezing point of 221oC [27] Although
the melting point for this system is highest in all the candidate mixtures in this group the lowest
12
combined compound cost makes it widely used in solar energy storage field Another ternary
system HITEC which contains NaNO3 KNO3 and NaNO2 has freezing point of 141 oC [28]
This combination brings the melting point down but the lack of combination of optimum features
limits its further application [29] Some mixtures such as LiNO3-Ca(NO3)2-KNO3 are not often
utilized because they increase the compound cost at the same time of lowering the melting point
to around 120oC [30] moreover the decreased melting point is still high compared to the
organic oil There are also several systems have the melting points less than 100oC or even 60
oC
they are not used in the parabolic trough solar power plant due to the decomposition of some
components during high temperature [31]
Table 21 Melting point of various nitrate salt systems
Compound Melting Point (ordmC)
LiNO3 253
NaNO3 307
KNO3 334
Ca(NO3)2 561
Sr(NO3)2 570
Ba(NO3)2 590
NaNO3-NaNO2 221
NaNO3-NaNO2-KNO3 141
NaNO3-KNO3-CaNO3 133
LiNO3-KNO3-NaNO3 120
KNO3-CaNO3-LiNO3 117
LiNO3-KNO3-NHNO3 92
KNO3-NHNO3-AgNO3 52
The melting points of individual and multi-component carbonate systems are listed in
Table 22 [26 32 33] Different from the nitrate salts the melting points for both the individual
13
and multi-component carbonate systems are on the higher side The lowest melting point is
achieved with lithium sodium and potassium carbonate ternary system whose melting point is
still 277oC higher than that of the nitrate ternary system with the same cations [32] Besides
because of the thermal decomposition issue the choice of component involved in the multi-
component carbonate systems is limited Some salt like CaCO3 doesn‟t have stable form at high
temperature and the lack of multi-component system reduces the chance of the synthesis of low
melting point salt mixtures Even though this group of salt is not thermally stable and the
working temperature range is relatively small it is still viewed as possible candidate working at
high temperature due to its low price
Table 22 Melting point of various carbonate salt systems
Compound Melting Point (ordmC)
Li2CO3 732
Na2CO3 858
K2CO3 900
MgCO3 990
Na2CO3-K2CO3 710
Li2CO3-Na2CO3 496
Li2CO3-K2CO3 488
Li2CO3-K2CO3-Na2CO3 397
Alkali and Alkaline fluoridechloride salts are also selected as one possible choice as the
thermal energy storage fluid and the melting point examined from previous literatures are given
in table 23 [34-38] A lot of study has been done for this group of salt and the melting points
were found in the same range as the carbonate group And for the pure salt metal chloride salts
have lower melting point than metal fluoride ones
14
Table 23 Melting point of various fluoridechloride salt systems
Compound Melting Point (ordmC)
LiF 849
NaF 996
KF 858
LiCl 610
NaCl 801
KCl 771
LiF-KF 493
LiF-NaF 652
LiCl-KF 487
LiF-NaF-KF 454
LiF-NaF-KF-MgF2 449
LiF-KF-BaF2 320
LiF-KF-CsF-RbF 256
Several studies were also conducted to determine the melting point of molten hydroxide
salts and the results are shown in Table24 The data of pure salts and multi-component mixtures
merely in this group were not much determined in the literatures Generally they are mixed with
other groups of anion and form some low melting point salt mixtures [39-42] On the basis of the
previous literature data alkali hydroxide salts and their mixture with salts in other groups have
relatively lower melting point compared with pure carbonate and fluoride chloride group salt
mixtures Most of the melting points given in Table 4 are lower than 300oC sodium potassium
hydroxide binary mixture even reaches the melting point below 200oC Accordingly relatively
large temperature range can be obtained by using hydroxide salt mixtures or adding them as
additive
15
Table 24 Melting point of various hydroixde salt systems
Compound Melting Point (ordmC)
LiOH-LiF 427
NaOH-KOH 170
LiOH-NaOH 213
NaOH-NaNO2 232
NaOH-NaNO3 237
NaOH-NaCl-NaNO3 242
NaOH-NaCl-Na2CO3 282
22 Density
For the solar energy storage system density for the thermal energy storage fluid is also
essential parameter The density is needed for the size calculation as function of temperature and
assessing for the thermal stability of thermoclines Besides density as function of temperature is
used to evaluate the volume change in the process of freezing which contributes to potential
stress
Alkalialkaline nitrate salts were studied very much about their density as function of
temperature All the results indicate that the density was decreased linearly as temperature
increases and any specific density value in the molten state can be expressed by equation as
equation 4
= A-BT [4]
Where (gcm3) is the density of salt A (gcm
3) is the initial density value at 0
oC and B
(mgcm3degC) is the density change slope as function of temperature The coefficients are shown in
16
Table 25 for the nitrate group molten salts Among these systems pure sodium nitrate has the
largest value which reveals the high initial density value at low temperature [43] Conversely
lithium nitrate has the lowest value while it presents the smallest decrease trend as temperature
increases [44] The densities and A B values of multi-component nitrate salts were included in
the range of those two salts discussed above
Table 25 Density coefficients A and B of nitrate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiNO3 1922 0556
NaNO3 2334 0767
KNO3 2127 0760
NaNO3-KNO3 2134 0773
KNO3-CaNO3-LiNO3 2172 0735
LiNO3-KNO3-NaNO3 2083 0715
Several experiments were also conducted to measure the density as function of temperature
for the individual and multi-component carbonate salt systems The density of the carbonate salt
also follow the same trend as that of nitrate salt and the temperature dependence of density
followed the linear equation as discussed above It is observed that all the carbonate salts have
higher initial density coefficient A than the nitrate salt The largest value is reached to 2511 and
even the lowest value in this group is greater than the maximum A of nitrate group [45-49]
What‟s more the regression slope coefficient B of carbonate salt is lower compared to that of the
nitrate salt group Accordingly the salts in this group present larger density in the molten state
and the density coefficient A and B are given in Table 26
17
Table 26 Density coefficients A and B of carbonate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
Li2CO3 2303 0532
Na2CO3 2350 0448
Na2CO3-K2CO3 2473 0483
Li2CO3-K2CO3 2511 0599
Li2CO3-Na2CO3 2456 0519
Li2CO3-Na2CO3-K2CO3 2364 0544
Density of metal fluoride and chloride molten salt were also examined and present similar
regression trend as temperature increases The linear temperature dependence is also expressed
by the same equation On the basis of previous literature data the pure chloride salt shows lower
density than the fluoride salt with the same cation in the molten state [49] What‟s more the
sodium halide salt has the largest density value while the lithium halide salt has the lowest value
which is very similar to the nitrate group salt The density determination coefficient A and B are
given in Table27
Table 27 Density coefficients A and B of chloridefluoride salts
Compound A(gcm3) Btimes103(gcm
3degC)
LiCl 1766 0432
NaCl 1991 0543
KCl 1976 0583
LiF 2226 0490
NaF 2581 0636
KF 2469 0651
LiF-NaF 2520 0818
LiCl-NaF-KCl 2436 0742
LiF-NaF-MgF 2240 0701
18
The density measurement of hydroxide was not conducted as much as those three anion
groups discussed above Only few data of density is available for the alkali hydroxide salt when
added into other salt systems and temperature dependence also follows the linear regression
trend [32 41] The density determination coefficient A and B are given in Table 28
Table 28 Density coefficients A and B of molten salt mixture with hydroxide salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiCl-LiOH 16 0443
LiF-LiOH 165 0471
23 Heat capacity
In the heating process the temperature of solar energy storage molten salt is increase by
absorbing energy from the solar radiation Conversely the same amount of heat is released and
applied to heating system in the process of cooling Heat capacity is the amount of heat required
to increase the temperature of certain material by 1 oC and can be viewed as the directly relevant
parameter to the energy storage ability To some extent the large heat capacity assures the
efficiency of the application of solar energy storage materials
The heat capacity of alkalialkaline nitrate salt was investigated for both individual and
multi-component system in the previous literature To simplify the comparison only the heat
capacity value at 500oC is shown in all the following tables In the liquid state the heat capacity
increases with temperature following linear equation and the increasing slope is as small as 10-5
to 10-4
[50 51] Among those alkali nitrate salt systems lithium nitrate has the largest heat
19
capacity at 500oC while potassium nitrate presents the lowest value at that temperature In table
29 the heat capacity results at the selected temperature in literature are given
Table 29 Heat capacity of alkali nitrate salt at 500oC
Compound Heat capacity(JgK)
LiNO3 2175
NaNO3 1686
KNO3 1400
NaNO3-KNO3 1533
LiNO3-KNO3 1642
LiNO3-KNO3-NaNO3 1681
For the carbonate salt systems in the molten state the heat capacity is almost constant and
almost independent with temperature [32 33] Same as the nitrate group salts the heat capacity
for pure carbonate salt decreases as the atomic number of the alkali element increases which
means the value for lithium carbonate is the largest and that of potassium carbonate is the
smallest Generally the heat capacity value for carbonate in molten state is larger than that in
solid state However the sodium-potassium carbonate binary system is an exception for which
the heat capacity in solid state is larger than liquid state In table 210 the heat capacity results of
carbonate salts at the selected temperature in literature are given
Table 210 Heat capacity of alkali carbonate salt at 500oC
Compound Heat Capacity(JgK)
Li2CO3 250
Na2CO3 178
K2CO3 151
Na2CO3-K2CO3 157
20
Li2CO3-K2CO3 160
Li2CO3-Na2CO3 209
Li2CO3-K2CO3-Na2CO3 163
The heat capacity of fluoridechloride salt was measured in several literature and found
that for the pure salt the lithium halide has the biggest heat capacity data in the molten state
while the potassium halides shows the lowest heat capacity value Similar to the carbonate group
the heat capacity value of fluoridechloride salt varies little with temperature in the liquid state
[32 33] The values at 500oC for the alkalialkaline halides are shown in Table 211
Table 211 Heat capacity of fluoridechloride salt at 500oC
Compound Heat Capacity (JgK)
LiCl 148
NaCl 115
KCl 090
LiF-KF 163
NaCl-MgCl2 100
LiF-NaF-KF 155
KCl-MgCl2-CaCl2 092
The heat capacity of pure and multi-component hydroxide salt systems is limited in the
previous literature and the values in the liquid state follow linear equation which is observed for
all the molten salt discussed above [52] The values at 500oC for the alkalialkaline halides are
shown in Table 212
21
Table 212 Heat capacity of hydroxide salt at 500oC
Compound Heat Capacity(JgK)
NaOH 188
LiOH-NaOH 221
NaOH-KOH 182
In summary on the basis of comparison of various physic-chemical properties molten
nitrate slats have relatively low melting point excellent working temperature range reasonable
density and high heat capacity As the result of that molten nitrate salt is suitable to be applied as
the thermal energy storage fluid in the solar energy storage system
22
CHAPTER 3
OBJECTIVES
Based on review of previous literature data it is found that there are several disadvantages
such as the high melting point relatively low density value or poor heat capacity in liquid state
which limit the application of molten salt in certain groups in solar thermal energy storage
system Conversely alkalialkaline nitrate salt is considered as the suitable choice and proposed
as the thermal energy storage liquid for high temperature
Currently the used thermal energy storage liquid is NaNO3 (60mol)-KNO3 (40mol)
binary system (solar salt) which has the melting point at 221oC [30] Although the melting point
for this salt mixture is not the lowest it is still emphasized because of its low investment cost
However there are some drawbacks for this binary nitrate mixture The main disadvantage is
the high melting point In evenings or in winter the molten salt can easily freeze and block the
pipeline As a result of that some auxiliary cost should be added to overcome this problem and
the total investment will be increased
Development and synthesis of newer molten salt mixtures with freezing point lower than
those currently used for thermal energy storage applications is necessary for higher efficiency of
utilization of solar energy and getting rid of any unnecessary cost The approach to develop
lower freezing point molten salt mixtures is by the prediction of new eutectic mixtures and also
23
by the development of new nitrate compounds Besides these two most well known systems
several other mixtures were also studied Preliminary evaluation of several new molten salt flux
systems based on requirements for thermal energy storage systems mainly including freezing
point density heat capacity viscosity and thermal energy storage density The promising
candidate low melting point molten salt system should satisfy the requirements that eutectic
melting temperatures are lower than 220oC and the thermal energy storage densities are higher
than binary solar salt It is known that the melting point can be lowered by the addition of one or
more ABNO3 nitrate compounds where A and B are cations Consequently several multi-
component systems which have more constituent salts than solar salt were came up with and
studied with little fundamental data on the physic-chemical properties at the required operating
conditions available at present
In this thesis the new systems with simulated eutectic compositions were tested for their
experimental melting points heat capacities using the Differential Scanning Calorimetry (DSC)
technique which is considered to be the accurate instrument for thermodynamic data analysis
[53-59] Some significant thermodynamic properties such as heat capacity enthalpy and entropy
and Gibbs energy were calculated in the thesis to evaluate the energy change of the system in the
phase change process and the potential of being applied in the parabolic trough solar power plant
The energy density was obtained by using the experimental measured density and heat capacity
of the mixtures in molten state Finally 9 down-selected systems were present and discussed
24
CHAPTER 4
THERMODYNAMIC MODELING OF SALT SYSTEMS
41 Thermodynamic modeling
To lower the melting point of solar energy storage system multi-component system is
applicable Thermodynamic model was introduced to predict the eutectic temperature of salt
systems based on the Gibbs energies of fusion of individual salt and that of mixing of constituent
binary systems At the eutectic temperature the Gibbs energies in the liquid state and solid state
of salt are equal In thermodynamics Gibbs energy of fusion can be expressed by the equation
given as follows
G = H-TS [5]
Where H is the change of enthalpy of fusion and S is the change of entropy of fusion Equally
the entropy change of fusion can be expressed by differentiating G and the equation is given
[6]
It is known that the change in entropy can be expressed in terms of change in heat capacity in the
melting process as
[7]
25
If the change of heat capacity is assume to be independent of temperature the integral of
from Tm to T can be shown as
[8]
where Sm is the entropy of fusion at the melting point which is equal to Accordingly
Eq8 can be rewritten as
[9]
Substituting Eq 9 in Eq 6 and integrating the equation from Tm to T we get
[10]
Eq 10 illustrates that by using the change of heat capacity melting point and enthalpy of fusion
the Gibbs energy change at any temperature can be obtained
The standard Gibbs energy of fusion of a salt bdquo1‟ can be expressed in terms of the activity
of the salt as
[11]
where is the molar excess Gibbs energy and X1 is the molefraction of the salt bdquo1‟ Gibbs
energy of fusion at any give temperature T is expressed by Eq 7 in terms of its molefraction and
partial molar excess Gibbs energy
26
Take LiNO3-NaNO3-KNO3 as an example in which the integral molar excess Gibbs energy is
composed of the summation of the Gibbs energies of three constituent binary system and one
ternary The expression of the integral excess Gibbs energy is given by Eq12
[12]
Gibbs energies of the three constituent binary systems LiNO3-NaNO3 LiNO3-KNO3 and
NaNO3-KNO3 of the LiNO3-NaNO3-KNO3 ternary system are taken from the literature [48 49]
The Gibbs energies of mixing or the integral excess Gibbs energies of the three constituent
binary systems of the LiNO3-NaNO3-KNO3 ternary system are given below
LiNO3-NaNO3 Binary System
Jmol [13]
LiNO3-KNO3 Binary System
Jmol [14]
NaNO3-KNO3 Binary System
Jmol [15]
When assume the intergral excess Gibbs energy of to be zero the excess Gibbs energy in
the ternary system can be expressed by the summation of three constituent binary systems
[16]
27
Generally the partial molar excess Gibbs energies are reduced from the integral molar
excess Gibbs energy and can be expressed by the generalized equation for certain ldquomrdquo
component salt as
[17]
In the ternary system the i value equals to 12 and 3 and the partial molar excess Gibbs energy
of mixing for each component can be expressed as follows
[18]
[19]
[20]
Based on Eq 7 and the partial molar excess Gibbs energy of individual component the
Gibbs energy in the fusion can be expressed as Eq21- 23
[21]
[22]
[23]
42 Calculations
The fusion of the ternary salt system is defined by solutions of Eq 21-Eq 23 Newton-
Raphson method can be used to solve these three non-linear equations by linearizing the non-
linear equations using the Taylor series and truncating the series to first order derivatives
28
Consider the three non-linear functions F G and H in three variables x y and z The three
equations that are solved for the three variables are written as
F(x y z) = 0
G(x y z) = 0
H(x y z) = 0 [24]
The partial derivatives of the function F with respect to x y and z are given as
[25]
Similarly the partials derivatives can be expressed for the other two functions G and H
Newton-Raphson iterative method of solving the three equations in three variables
essentially deals with the solution of the incremental vector in the matrix equation given below
[26]
For the initial values of x y and z (say xi yi and zi) the right hand side vector contains the
values of the functions at the initial values (xi yi and zi) The 3times3 matrix on the left hand side
contains the partial derivatives of the functions with respect to the three variables at the initial
values Solutions of the matrix equation (Eq 26) result in the increments of the variables x y
and z The variables for the next iteration will then be xi + x yi + y and zi + z The
process of solving the matrix equation (Eq 26) is continued until the increments in the variables
x y and z is less than a very small quantity The iteration process is then said to be
29
converged and the values of the variables at convergence of the solution are the roots of the
system of the three fusion equations
The composition of LiNO3 NaNO3 and KNO3 and the eutectic temperature is solved by
using the Newton-Raphson iterative method Different from the data in previous literature the
eutectic temperature for the ternary is 116oC Besides the composition for each component is
also different from those published in literatures The new molten ternary system is composed of
2592 wt LiNO3 2001 wt NaNO3 and 5407 wt KNO3 The similar method is also applied
to other multi-component systems to determine the composition and eutectic temperature The
predicted melting points for new solar energy storage system are given Table41
Table 41 Calculated composition and melting point of multi-component molten salts systems
System Composition (wt) Calc Tmp
LiNO3 NaNO3 KNO3 NaNO2 KNO2 Mg(NO3)2 MgKN (degC)
Salt 1 259 20 541 - - - - 116
Salt 2 - 161 547 292 - - - 1238
Salt 3 175 142 505 178 - - - 986
Salt 4 115 104 274 - - - 507 986
Salt 5 172 139 476 172 41 - - 957
Salt 6 9 423 336 - 151 - - 1000
Salt 7 193 - 546 237 24 - - 1081
Salt 8 193 - 559 239 - 09 - 1008
Salt 9 154 172 324 - - 83 267 1036
30
CHAPTER 5
EXPERIMENTAL PROCEDURE
51 Melting point determination of molten salt mixtures
511 Materials
Ternary quaternary and quinary nirate and nitrite mixtures were tested in the thesis Most
components in the mixtures don‟t require any pre-preparation and can be used as received The
only exception is new developed MgKN which was composed of 6667 mol KNO3 and 3333
mol Mg(NO3)2 This unique compound is synthesized from magnesium nitrate hexahydrate
(98 Alfa Aesar) and potassium nitrate (ACS 990 min Alfa Aesar) and added into the
mixture as one single component As received magnesium nitrate hexahydrate is dehydrated
before synthesizing MgKN compound Weighted amount of magnesium nitrate taken in a
stainless steel crucible and placed on a hot plate in an argon atmosphere Temperature of the salt
is measured with a thermocouple immersed in the salt The temperature was held at 52315 K for
2 hours The salt solidifies to a white mass The temperature of the salt is then raised to 57315 K
slowly to remove any traces of moisture and to ensure complete dehydration The complete
removal of water is ascertained by weight loss
512 Apparatus and Procedure
31
Differential scanning calorimetry (DSC) analysis was performed using Perkin Elmer
Diamond DSC instrument and the setup is shown in fig 51 Heat flow and temperature can be
recorded in the instrument with an accuracy of 00001 mW and 001 K respectively The
measurements were made under purified nitrogen atmosphere with a flow rate of 20ccmin and at
a heating rate of 5 Kmin
Fig 51 Photography of set-up for DSC equipment
After dehydration if necessary each component was weighed to an accuracy of 01mg with
the electrical balance and mixed thoroughly in a stainless steel crucible Later the mixture is
heated up to certain temperature at which the entire salt melts At this temperature the salt
mixture was held for about 30 minutes The salt mixture is allowed to air cool to ambient
temperature This procedure is repeated 3 to 4 times to get the well-mixed compound Standard
aluminum pan with lid used for DSC measurements are weighed before the experiment Small
amount of the synthesized compound is placed carefully in the aluminum pan and closed with
the lid The lid is crimped by a sample press and the pan is weighed The weight of the sample is
32
determined by removing the weight of the pan and lid For the determination of melting point
and heat capacity (20-25) mg of the sample was used
Perkin-Elmer Diamond Differential Scanning Calorimeter (DSC) is used to measure the
melting point and heat capacity of compound The crimped ample pan was immediately put
inside the sample chamber of DSC after preparation and held at 52315 K for 10 hours to remove
the trace amount of moisture possibly caught in the process of loading sample and also to ensure
a homogeneous mixture In the experimental procedure a temperature range from 29815 K to
52315 K was set with a heating rate of 5 K min
1 followed by a cooling cycle at the same rate
This cycle is repeated for at least 6 times to ensure good mixture of the sample and
reproducibility of the results
52 Heat Capacity determination of molten salt mixtures
To start Cp measurement the same procedure as that of melting point determination is
followed with an addition of bdquoiso-scan-iso‟ steps to the program after 5-cycle temperature scan
Starting from 29815 K the temperature was held for 5 minutes before and after each scan step
Small temperature scan range is chosen to avoid thermal resistance between device and testing
sample except when the temperature is approaching the melting temperature The upper limit for
the Cp measurement was set to 62315 K in our experiments Since the change in the molar heat
capacity of the salt in the liquid state is very small the Cp data in the liquid state can be easily fit
to an equation and extrapolated to higher temperatures To get the value of molar heat capacity
of the sample heat flow curve for the baseline of the empty sample pan also needs to be obtained
immediately following the identical ldquoiso-scan-isordquo steps which were used for the actual sample
33
run The difference of heat flow between the actual crimpled sample and the empty sample pan is
the absolute heat absorbed by the test sample
53 Density determination of molten salt mixtures
Density measurement was carried out with standard densitometer which has fixed volume
Initial weight of the densitometer is measured and noted Salt composition of which the density
is measured is placed in a beaker on a hot place The densitometer is also placed on the same hot
plate The temperature is set to a fixed value above the melting point of the salt and is measured
by a thermocouple After the salt is melted and when the temperature shows stable reading the
molten salt is poured in to the densitometer up to the set mark on the sensitometer bottle The
weight of the densitometer with the molten salt is measured The weight difference between this
weight and the weight of empty densitometer gives the weight of the molten salt at the fixed set
temperature By knowing the fixed volume in the densitometer the density of the salt at that
temperature can be calculated This procedure is repeated at least three times to accurately
determine the density of the salt
34
CHAPTER 6
RESULT AND DISCUSSION
61 Melting point determination
611 DSC equipment calibration
Before the actual melting point measurement pure indium zinc metal and several
individual salts were used to calibrate the DSC equipment For metals only one sharp peak was
observed for each and the heat flow curve for indium metal is shown in fig 61 However larger
and boarder peaks are found for salts just like the condition illustrated in fig 62 for pure
potassium nitrate Based on the results shown in Table 61 the experimental data for melting
points and enthalpies of fusion have excellent agreement with the literature values [60-63] The
variation of point is within 07 and the variation of change of enthalpy is less than 3
Figure 61 Melting point calibration with indium sample
35
Figure 62 Melting point calibration with KNO3 sample
Table 61 Calibration data of melting points with different samples
Sample
Lit
Tmp
Expt
Tmp
Lit
Ttrans
Expt
Ttrans
Lit
ΔHfusion
Expt
ΔHfusion
Lit
ΔHtrans
Expt
ΔHtrans
degC degC degC degC Jg Jg Jg Jg
Indium 1566 1563 - - 286 278 - -
Zinc 4195 4188 - - 1086 1068 - -
LiNO3 2567 2550 - - 3617 3633 - -
NaNO3 3100 3081 2770 2753 1777 1756 147 152
KNO3 3370 3372 1330 1332 993 1005 538 529
612 Results
Differential scanning calorimetry (DSC) was used to determine the melting point and any
solid state phase transitions of the salt mixture A low scanning rate was chosen to record the
heat flow curve as function of temperature in order to improve the sensitivity of detection [64] It
helps to pick up any small endothermic peaks and also avoids the thermal resistance between the
36
internal furnace and sample Nine systems were chosen to test and the eutectic composition is
already listed in Table 41
All the selected systems are composed of alkaline nitrate and nitrite and most of them have
three basic components which are lithium sodium potassium nitrate or nitrite All the quaternary
and quinary systems were developed on the basis of the LiNO3-NaNO3-KNO3 baseline ternary
Figure 63-611 shows the DSC plot of all the salt systems DSC plots for each system were
collected for at least five runs (each run with fresh salt preparation) to ensure the reproducibility
All the onset temperatures peak temperatures predicted temperatures enthalpy of fusion for
melting peaks and the solid phase transformation temperatures are given in Table62
Figure 63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt
37
Figure 64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt
Figure 65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt
38
Figure 66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt
Figure 67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt
39
Figure 68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
Figure 69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
40
Figure 610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt
Figure 611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN salt
Table 62 illustrates that the predicted melting point is close to the experimental
determined value and most deviation is within 10 except for system 9 The great agreement
41
between experimental and calculated data verifies the accuracy and feasibility of the
thermodynamic modeling
Table 62 DSC results of melting point transition point and predicted melting point
System Tmp Ttrans ΔHfusion
Calculated degC Onset degC Peak degC Peak degC Jg
Salt 1 1160 994 1191 1043 600
Salt 2 1238 1150 1240 NA 97
Salt 3 986 940 999 NA 244
Salt 4 986 940 1010 NA 60
Salt 5 957 910 950 NA 62
Salt 6 1000 930 960 NA 86
Salt 7 1081 992 1003 793 60
Salt 8 1008 1010 1019 853 59
Salt 9 1036 834 892 NA 93
613 Discussion
It is observed that the first curve is different from last ones shown in the DSC plots and
this phenomenon is common for all the melting point measurement with DSC technique This
happened because in the first cycle the moisture caught by salt mixture especially the lithium
nitrate was removed in the process of heating Moreover the partially solidified sample in the
sample loading process can be re-homogenized in the first heating cycle [65-67] In figure 63
69 and 610 more than one endothermic peak was found The first smaller endothermic peak
refers to solid state phase transition of the salt mixture The second larger endothermic peak
refers to the melting of the salt Normally the onset temperature of transition is taken as the
experimental transition point for any metallic sample However in case of molten salts mixtures
since the thermal conductivity is low [68-74] the complete transition is ensured only at the peak
42
transition temperature The thermal gradient which exists due to the low thermal conductivity of
the salt results in internal heat flow which enhances the mixing in the salt Thus the transition
temperature is defined as the peak temperature of phase transition For salt No1 the small
endothermic peak happened before and was connected to the main peak which occurred at
39027K The first endothermic peaks for salt No 7 and 8 occurred at almost the same
temperature because of the similar composition for these two compounds Since the small
amount of magnesium nitrate and potassium nitrite contained in these two compounds the small
endothermic peak can hardly be related to these two components Obviously the rest three major
components must have something to do with the first peaks happened before the melting peaks
for both cases Each component among the major three ones were tested to find out any possible
solid phase transition peaks of them and the results shown in Table 63 which reveals that
lithium nitrate doesnt have any phase transition peak in solid state while potassium nitrate and
sodium nitrite both own the solid phase transformation peaks before their melting peaks
Table 63 Fusion and solid phase transition temperature for individual salts
System Tmp degC Ttrans degC ΔHfusion Jg ΔHtrans Jg
LiNO3 2550 - 3633 -
KNO3 3372 1332 1005 529
NaNO2 4311 4170 1119 880
The further investigation was carried out by running the KNO3-NaNO2 (550 wt and 238 wt )
binary compound with the very similar weight percentage as that in salt No 7 (546 wt and
237 wt) and salt No 8 (559wt and 239wt) By converting the weight percentage of the
studied binary system into 100 scale the weight fraction for sodium nitrate and potassium
nitrate can be rewritten as 698wt and 302wt The DSC plot for this binary system was
43
shown in fig 612 Although the solid transition and melting temperature were brought down by
adding lithium nitrate the shape of the plots in fig 69 and 610 are identical to that shown in fig
612 The enthalpy of solid state transformation of the binary salt was also converted to that in
both quaternary systems by using the weight fraction occupied by the binary system and the
comparable change of converted enthalpy between the binary system and two quaternary systems
indicates the relevance of the solid transition peaks in salt 7 and 8 to the combined effect of
potassium nitrate and sodium nitrite
Figure 612 DSC plot of 698wt KNO3- 302wt NaNO2 binary system
The similar analysis was applied to No1 salt to find out the reason for the presence of a
small peak adherent to the main melting peak before the melting point Sodium nitrate and
potassium nitrate binary system was synthesized based on the weight fraction of these two
constituent salts in No 1 salt DSC plot for the sodium nitrate-potassium nitrate binary system in
Fig 613 with the converted composition which is essentially same as that in the No1 ternary
system shows smooth heat flow curve before the melting peak which means the solid transition
peak in ternary is not simply relative to the binary system Assumption was made that the solid
44
phase transformation peak in the ternary salt is resulted from a multiple effect ie the
combination of one of the eutectic binary system involved in the ternary salt mixture and the
other binary system which is composed of the rest components The statement is verified that the
small peak in salt 1 is mainly caused by the solid phase transformation peak in lithium nitrate-
potassium nitrate eutectic binary system given the similar shape of the DSC plots in Fig 614
Since in salt No1 there is excess amount of sodium nitrate to form the lithium nitrate-sodium
nitrate binary system the rest sodium nitrate can interact with potassium nitrate and form new
sodium-potassium nitrate system which is shown in fig615 Besides a solid phase
transformation peak is observed in fig615 which has a very small area and won‟t change the
shape of phase transformation peak in fig614 when these two binary systems are combined and
form salt 1 The enthalpies of solid state transformation in two binary salts were also converted
to that in salt 1 by using the weight fractions occupied by both binary systems The difference
of the change of converted enthalpies between the lithium-potassium nitrate eutectic binary and
ternary system is filled by the binary mixture which is composed of the rest components sodium
nitrate-potassium nitrate The comparable converted values of enthalpy change between salt 1
and its two constituent binary systems further verify the assumption that the solid phase
transformation happened in salt 1 is mainly due to the combined effect of LiNO3-KNO3 eutectic
binary system and NaNO3-KNO3 binary system
45
Figure613 DSC plot of 270wt NaNO3-730wt KNO3 binary system
Figure614 DSC plot of 458wtLiNO3-542wtKNO3 binary system
46
Figure615 DSC plot of 460wt NaNO3-540wt KNO3 binary system
Unlike those discussed mixtures above salt No2 Salt No4 Salt No5 and Salt No6 have
only one relatively board melting peak and the heat flow curve before and after are very stable
Similarly there is no solid transformation peaks observed in salt No3 salt No7 and salt No8
However the heat flow after the melting peak in these cases are not stable and the main
endothermic peak is followed by a small hump which is considered to be the recrystallization
process once the compound entered into the liquid state When the process is finished the heat
flow curve returns to steady state
Heating rate is a significant parameter when collect the heat flow curves by using DSC
technique Fig 616(a) and Fig 616(b) illustrate the difference of melting point for salt No6 due
to the change of heating rate If the heating rate is 20oCmin the peak temperature and onset
temperature for the melting peak is 9669oC and 9221
oC respectively Once the heating rate is
decreased to 5oCmin these two temperatures will also be lowered to 9614
oC and 9190
oC The
difference is resulted from the diverse amount of thermal resistance between the testing sample
and the furnace inside the DSC instrument [75] Under higher heating rate the decisive thermal
47
resistance is raised due to the low thermal conductivity medium between the furnace and the
actual sample The insensitivity of gas heat conduction medium in DSC results each unit of
temperature increase on one side cannot have an immediate response on the other side of the gas
Consequently the sample holder which is connected the furnace has a higher temperature than
that inside the sample In this condition the value of temperature profile collected as the sample
holder temperature is larger than the actual temperature The deviation will be much smaller
when the heating rate is reduced In the case the thermal resistance will be decreased because of
the lower temperature gradient of the gas medium in the heating process As a result of that the
collected temperature from the sensor attached to the sample holder will be very close to the
actual temperature inside the testing sample
Figure 616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 20oCmin
heating rate
48
Figure 616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 5oCmin
heating rate
Besides the difference of temperature while using higher and lower heat rate the solution
of DSC will also be affected by different heating rate Fig 617(a) shows the DSC plot for salt
No 7 using the heating rate as 5oCmin and the DSC plot in Fig 617(b) is collected under the
heating rate as 20oCmin It can be observed that in the lower heating rate two small separated
peaks can be viewed as two parts of the solid phase transformation process while in Fig 617(b)
two small peaks before the melting peak merge and present as a board hump The qualification
of resolution can be executed by the term named resolution factor RMKE which is calculated as
the ratio of the peak heat flow value of the separated peaks to that of the concave point between
two peaks The equation for determining RMIKE is given in Eq 27 [76 77]
RMIKE =hpeakhmin [27]
49
Figure 617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 5oCmin
heating rate
Figure 617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 20oCmin
heating rate
In the case of lower heating rate the RMKE is determined to be 15 and the value for higher
heating rate is not available because the concave point of heat flow doesn‟t exist from
Fig617(b) Since the higher RMKE value indicates better resolution it can be stated that the
50
lower heating rate also results in greater sensitivity of the equipment to pick up any small
endothermic peaks
Besides the down-selected 9 compounds some more salt mixtures were also tested Most
of them were not selected to the final candidate for the thermal energy storage application
because of their higher melting point Table 64 gives some of the trial systems measured with
DSC technique It is illustrated that the melting points of mixtures with lower or even no content
of lithium nitrate turn out to be higher than those with sufficient amount of lithium nitrate For
most of the mixtures with melting point lower than 120oC the amount of lithium nitrate should
be larger than 81wt Also all of the systems in table 64 with lithium nitrate less than 15wt
have melting point higher than 140oC Based on the observation above it is concluded that the
lithium nitrate can be used as an additive to bring the melting point down for thermal energy
storage systems
51
Table 64 Melting points of candidate systems as function of temperatures
System Composition (wt)
Onset
Temp
Peak
Temp
(oC) (
oC)
LiNO3 ndash NaNO3 ndash KNO2 107 459 434 890 910
LiNO3 - KNO3 - NaNO2 196 564 241
1024 1046
LiNO3 - NaNO3 - KNO3 - KNO2 90 423 337 151
930 960
LiNO3 - NaNO3 - NaNO2 - KNO2 81 454 65 401
900 910
LiNO3 - KNO3 - NaNO2 - KNO2 193 546 237 24
992 1003
LiNO3 - KNO3 - NaNO2 ndash Mg(NO3)2 193 559 238 09
1010 1020
LiNO3 - NaNO3 - KNO3 - Mg(NO3)2
- MgK 154 172 324 83 267 834 892
LiNO3 - NaNO3 - KNO2 ndash Ca(NO3)2 14 390 333 263
1250 1470
NaNO3 - KNO3 - NaNO2 - KNO2 425 163 71 341
1407 1447
NaNO3 - KNO3 - KNO2 ndash Mg(NO3)2 432 146 380 42
1386 1421
NaNO3 - NaNO2 - KNO2 - Ca(NO3)2 451 92 410 48
1150 1390
LiNO3 - NaNO3 - NaNO2 - KNO2 -
Ca(NO3)2 15 393 37 323 232 1380 1480
LiNO3 - NaNO3 - KNO2 - Ca(NO3)2 -
Mg(NO3)2 14 379 313 275 20 1339 1534
62 Heat capacity determination
621 Heat capacity calibration
DSC was also calibrated for the heat capacity measurement Lithium nitrate sodium
nitrate and potassium nitrate were examined for the heat capacities from room temperature to
upper limit temperature for the instrument In liquid state the heat capacity values for each salt
can be fit to straight line with trace amount of increasing trend Since the temperature range from
the onset temperature of liquid state to the upper limit of DSC is relatively small the heat
capacity values for pure individual salts can be viewed as constants The comparison between the
theoretical and experimental heat capacity data is given in Table 65 Except lithium nitrate the
52
experimental heat capacities data for the rest two systems are almost same as the literature Even
for lithium nitrate which demonstrates the biggest difference from the literature data the 28
vibration is still within a reasonable range
Table 65 Calibration data of heat capacities with different samples
Sample Lit Cp Expt Cp
JgK JgK
LiNO3 218 212
NaNO3 169 167
KNO3 140 139
622 Results
The materials used in the heat capacity measurements are the same as those in the melting
point experiments Molar heat capacities of the all compound were measured by the DSC
equipment from room temperature to 62315 K The heat flow is recorded as a function of
temperature in ldquoiso-scan-isordquo steps at intervals of 20 K The bdquoiso stage‟ refers to isothermal
holding at a particular temperature bdquoscan stage‟ refers to the heat flow recording at a heating rate
of 5 K min1
up to a an increment of 25 K followed by another isothermal holding stage This is
a standard procedure followed in the measurement of heat capacity of materials using the DSC
equipment [63 64] This procedure of heat capacity measurement has two advantages (i) any
heat fluctuations during the recording are avoided by the isothermal steps and (ii) any phase
transition can be highlighted by the choice of temperature range The absolute heat flow to the
sample is determined by subtracting the heat flow collected by running a baseline curve with an
empty pan Because the heat capacity measurement in the heating process corresponds to
53
collecting the value of required heat flow at each temperature all the heat capacity plots have the
same shape with that of heat flow in the melting point measurements Take the heat capacity plot
of LiNO3-NaNO3-KNO3 ternary system as an instance which is shown in fig 618 the heat
capacity curve also has two different peaks The first little peaks corresponds to one occurs at
39027K which was observed in fig 63 the second large and sharp peak happened right after the
small one is prevalent to the endothermic peak with the peak temperature as 39027 K Similarly
after the phase transformation the heat capacity in liquid state becomes very stable and increase
with temperature linearly with little slope
Fig 618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system as function of
temperature
The heat capacity change as function of temperature for salt No1 was illustrated in fig
619 Based on the trend of heat capacity in the liquid state any value for the system in the liquid
can be extrapolated The expressions for heat capacity in liquid state for the new molten salt
systems were discussed and given in the next sectionTable66 shows the specific heat capacity
54
of the all the selective compounds measured at 62315 K and extrapolated at 77315K Besides
the molar heat capacities at 77315K are given in Table 66 of all the salts
Fig 619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K
Table 66 Heat capacity of selected new TES molten salt mixtures
System Expt (62315K) Extrapolated(77315K) Extrapolated(77315K)
Cp JgK Cp JgK Molar Cp JmolK
Salt 1 153 170 1521
Salt 2 143 168 1515
Salt 3 148 155 2183
Salt 4 153 166 1411
Salt 5 153 170 1440
Salt 6 151 163 1435
Salt 7 156 167 1443
Salt 8 155 168 1410
Salt 9 161 170 1937
55
623 Thermodynamic properties
The standard thermodynamic properties such as entropy enthalpy and Gibbs energy for
salt mixtures are determined from the experimental data of melting point and heat capacity in the
temperature range of the present study and expression for determining these properties are given
in equation 28-30 In thermodynamics all these three properties are related to heat capacity and
its variances with temperature In the studied temperature range (29815K-62315K) they can be
described as expression includes heat capacity
[28]
[29]
[30]
Where Tt is the solid transformation temperature Tmp is the melting point ΔHt is enthalpy of
solid phase transformation and ΔHfusion is enthalpy of fusion The standard thermodynamic
properties entropy enthalpy and Gibbs energies as function of temperature for each compound
are expressed in the following section
6231 LiNO3-NaNO3-KNO3 (Salt 1)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3
compound (i) solid state 1 (32315-38415) K (ii) liquid state (40315-62315) K Accordingly
56
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62311 Heat capacity of solid state 1 (29815-38415) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the solid state 1 in the
temperature range of 29815 to 38415 K is fit to a second order polynomial equation Eqn (31)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[31]
( ) K
R2 = 0982
62312 Heat capacity of liquid state (40315-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a linear equation Eqn (32) gives the linear
equation along with the least square fit parameter (R2) in the temperature range for the liquid
state of the compound
JKmol [32]
57
R2 = 0947
Heat capacity data of the LiNO3-NaNO3-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62313 Thermodynamic properties of solid state 1(29815-38415) K
JKmol [33]
Jmol [34]
[35]
Jmol
62314 Thermodynamic properties of liquid state 2(40315-62315) K
[36]
58
JKmol
Jmol [37]
[38]
Jmol
Among the equations above equation (33)-(35) refer to the thermodynamic properties for
solid state equations (36)-(38) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature ranges for solid and liquid state are
given in Table A1 and A2 in appendix A respectively with the corresponding heat capacity as
function of temperature
6232 NaNO3-NaNO2-KNO3 (Salt 2)
The heat capacity data can be divided into two sections for NaNO3-NaNO2-KNO3
compound (i) solid state 1 (32315-39215) K (ii) liquid state (41315-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62321 Heat capacity of solid state 1 (29815-39215) K
59
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the solid state in the
temperature range of 29815 to 39215 K is fit to a second order polynomial equation Eqn (39)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[39]
( ) K
R2 = 0978
62322 Heat capacity of liquid state (40315-62315) K
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a second order polynomial equation Eqn (40)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[40]
R2 = 0941
60
Heat capacity data of the NaNO3-NaNO2-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62323 Thermodynamic properties of solid state 1(29815-39215) K
JKmol [41]
Jmol [42]
[43]
Jmol
62324 Thermodynamic properties of liquid state 2(40315-62315) K
JKmol [44]
61
Jmol [45]
[46]
Jmol
Among the equations above equation (41)-(43) refer to the thermodynamic properties for
solid state equations (44)-(46) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table B1 and B2 in appendix B respectively with the corresponding heat capacity as
function of temperature
6233 LiNO3-NaNO3 -KNO3-MgK (Salt 3)
The heat capacity data can be divided into two sections for LiNO3-NaNO3 -KNO3-MgK
compound (i) solid state 1 (29815-36415) K (ii) liquid state (42115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62331 Heat capacity of solid state 1 (29815-36415) K
62
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the solid state in the
temperature range of 29815 to 36415 K is fit to a second order polynomial equation Eqn (47)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[47]
( ) K
R2 = 0995
62332 Heat capacity of liquid state (42115-62315) K
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the liquid state in the
temperature range of 42115 to 62315 K is fit to a second order polynomial equation Eqn (48)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[48]
R2 = 0963
63
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
62333 Thermodynamic properties of solid state 1(29815-36415) K
JKmol [49]
Jmol [50]
[51]
Jmol
62334 Thermodynamic properties of liquid state 2(42115-62315) K
64
JKmol [52]
Jmol [53]
[54] [29]
Jmol
Among the equations above equation (49)-(51) refer to the thermodynamic properties for
solid state equations (52)-(54) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table C1and C2 in appendix C respectively with the corresponding heat capacity as
function of temperature
6234 LiNO3-NaNO3-KNO3-NaNO2 (Salt 4)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-NaNO2
compound (i) solid state 1 (29815-36315) K (ii) liquid state (38115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62341 Heat capacity of solid state 1 (29815-36315) K
65
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the solid state in the
temperature range of 29815 to 36315 K is fit to a second order polynomial equation Eqn (55)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[55]
( ) K
R2 = 0995
62342 Heat capacity of liquid state (38115-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the liquid state in the
temperature range of 38115 to 62315 K is fit to a second order polynomial equation Eqn (56)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[56]
R2 = 0972
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
66
62343 Thermodynamic properties of solid state 1(29815-36315) K
JKmol [57]
Jmol [58]
[59]
Jmol
62344 Thermodynamic properties of liquid state 2(38115-62315) K
JKmol [60]
Jmol [61]
67
[37]
Jmol [62]
Among the equations above equation (57)-(59) refer to the thermodynamic properties for
solid state equations (60)-(62) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table D1 and D2 in appendix D respectively with the corresponding heat capacity as
function of temperature
6235 LiNO3-NaNO3-NaNO2-KNO3-KNO2 (Salt 5)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-NaNO2-KNO3-
KNO2 compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62351 Heat capacity of solid state 1 (29815-35915) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
in the temperature range of 29815 to 35915 K is fit to a second order polynomial equation Eqn
(63) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
68
[63]
( ) K
R2 = 0996
62352 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the liquid
state in the temperature range of 37515 to 62315 K is fit to a second order polynomial equation
Eqn (64) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[64]
R2 = 0969
Heat capacity data of the LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62353 Thermodynamic properties of Solid state 1(29815-35915) K
JKmol [65]
69
Jmol [66]
[67]
Jmol
62354 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [68]
Jmol [69]
[45]
Jmol [70]
70
Among the equations above equation (65)-(67) refer to the thermodynamic properties for
solid state equations (68)-(70) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table E1 and E2 in appendix E respectively with the corresponding heat capacity as
function of temperature
6236 LiNO3-NaNO3-KNO3-KNO2 (Salt 6)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-KNO2
compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62361 Heat capacity of solid state 1 (29815-36515) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the solid state in the
temperature range of 29815 to 36515 K is fit to a second order polynomial equation Eqn (71)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[71]
( ) K
R2 = 0998
71
62362 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the liquid state in the
temperature range of 37515 to 62315 K is given in Table 20 The data is fit to a second order
polynomial equation Eqn (72) gives the linear equation along with the least square fit parameter
(R2) in the temperature range for the liquid state of the compound
[72]
R2 = 0953
Heat capacity data of the LiNO3-NaNO3-KNO3-KNO2 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62363 Thermodynamic properties of solid state 1(29815-35915) K
JKmol [73]
Jmol [74]
72
[75]
Jmol
62364 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [76]
Jmol [77]
Jmol [78]
Among the equations above equation (73)-(75) refer to the thermodynamic properties for
solid state equations (76)-(78) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
73
given in Table F1 and F2 in appendix F respectively with the corresponding heat capacity as
function of temperature
6237 LiNO3-KNO3-NaNO2-KNO2 (Salt 7)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62371 Heat capacity of solid state 1 (29815-35415) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 1 in
the temperature range of 29815 to 35415 K is fit to a second order polynomial equation Eqn
(79) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[79]
(29815-35415) K
R2 = 0993
62372 Heat capacity of solid state 2 (36215-37315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 2 in
the temperature range of 36215 to 37315 K is fit to a second order polynomial equation Eqn
74
(80) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 2 of the compound
[80]
R2 = 0977
62373 Heat capacity of liquid state (37915-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the liquid state in the
temperature range of 37915 to 62315 K is fit to a linear equation Eqn (81) gives the
polynomial equation along with the least square fit parameter (R2) in the temperature range for
the liquid state of the compound
[81]
R2 = 0961
Heat capacity data of the LiNO3-KNO3-NaNO2-KNO2 compound in the two solid states
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62374 Thermodynamic properties of solid state 1(29815-35415) K
75
JKmol [82]
Jmol [83]
[84]
Jmol
62375 Thermodynamic properties of solid state 2(36215-37315) K
JKmol [85]
Jmol [86]
76
[87] [62]
Jmol
62376 Thermodynamic properties of liquid state (37915-62315) K
JKmol [88]
Jmol [89]
Jmol [90]
Among the equations above equation (82)-(84) refer to the thermodynamic properties for
solid 1 equation (85)-(87) refer to the thermodynamic properties for solid 2 equations (88)-(90)
refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy values
77
in the studied temperature range for solid 1 solid 2 and liquid state are given in Table G1-G3 in
appendix G respectively with the corresponding heat capacity as function of temperature
6238 LiNO3-KNO3-NaNO2-Mg(NO3)2 (salt 8)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62381 Heat capacity of solid state 1 (29815-33715) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid
state 1 in the temperature range of 29815 to 33715 K is fit to a second order polynomial
equation Eqn (91) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the solid state 1 of the compound
[91]
(29815-33715) K
R2 = 0994
62382 Heat capacity of solid state 2 (36115-36415) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid state 2
in the temperature range of 36115 to 36415 K is given in Table 4 The data is fit to a second
78
order polynomial equation Eqn (92) gives the polynomial equation along with the least square
fit parameter (R2) in the temperature range for the solid state 2 of the compound
[92]
R2 = 0992
62383 Heat capacity of liquid state (41115-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the liquid state in
the temperature range of 41115 to 62315 K is given in Table 5 The data is fit to a linear
equation Eqn (93) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the liquid state of the compound
[93]
R2 = 0934
Heat capacity data of the LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the two solid
states follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62384 Solid state 1(29815-35415) K
79
JKmol [94]
Jmol [95]
[96]
Jmol
62385 Solid state 2(36115-36415) K
JKmol [97]
80
Jmol [98]
[99] [74]
Jmol
62386 Liquid state (41115-62315) K
JKmol [100]
Jmol [101]
Jmol [102]
Among the equations above equation (94)-(96) refer to the thermodynamic properties for
solid 1 equation (97)-(99) refer to the thermodynamic properties for solid 2 equations (100)-
(102) refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy
81
values in the studied temperature range for solid 1 solid 2 and liquid state are given in Table H1
and H2 in appendix H respectively with the corresponding heat capacity as function of
temperature
6239 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK(Salt 9)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-
Mg(NO3)2-MgK compound (i) solid state 1 (29815-35315) K (ii) liquid state (39115-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62391 Heat capacity of solid state 1 (29815-35315) K
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state in the temperature range of 29815 to 35315 K is fit to a second order polynomial equation
Eqn (103) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[103]
( ) K
R2 = 0996
62392 Heat capacity of liquid state (39115-62315) K
82
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the liquid
state in the temperature range of 39115 to 62315 K is fit to a second order polynomial equation
Eqn (104) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[104]
R2 = 0951
Heat capacity data of the LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62393 Solid state 1(29815-35315) K
JKmol [105]
Jmol [106]
83
[107]
Jmol
62394 Liquid state 2(39115-62315) K
JKmol [108]
Jmol [109]
[110]
Jmol
Among the equations above equation (105)-(107) refer to the thermodynamic properties
for solid state equations (108)-(110) refer to thermodynamic properties of the liquid The
entropy enthalpy and Gibbs energy values in the studied temperature range for solid and liquid
state are given in Table I1 and I2 in appendix I respectively with the corresponding heat
capacity as function of temperature
84
624 Discussion of Gibbs energy change for molten salts
The Gibbs energy change data as function of temperature for 9 systems are given in fig
620 and the values at 62315K are shown in Table 67 Every system demonstrates continuous
curve throughout the whole studied temperature range Most of systems have similar Gibbs
energy change values for each temperature spot due to the comparable compositions and
properties of constituent salts However salt 3 and salt 9 Both of these salts have certain
amount of MgKN compound which presents large absolute amount of change of Gibbs energy in
the same studied temperature range [66] Since the change of Gibbs energy for multi-component
mixture is relevant to that of each constituent salt the large absolute value of ΔG of MgKN
mainly contributes to the largely negative value of salt 3 and salt 9 shown in fig 620 Besides
it is observed that most systems contain nitrite salts present lower absolute value of Gibbs energy
change For example salt 1 doesn‟t include any nitrite salt and has a relatively high absolute
value of Gibbs energy change as 1704kJmol while other systems having nitrite salts show lower
value varies from 1372kJmol to 1592kJmol
85
Fig 620 Change of Gibbs energy as function of temperature for molten salt systems
Table 67 Change of Gibbs energy values at 62315K for molten salt systems
SNo System ΔG(kJmol)
1 LiNO3-NaNO3-KNO3 1704
2 NaNO3- NaNO2- KNO3 1372
3 LiNO3- NaNO3- KNO3- MgKN 2807
4 LiNO3- NaNO3- KNO3- NaNO2 1443
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1441
6 LiNO3-NaNO3-KNO3-KNO2 1570
7 LiNO3-KNO3-NaNO2-KNO2 1592
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1583
9 LiNO3-NaNO3-KNO3-Mg(NO3)2 -MgKN 2217
86
63 Density determination
631 Density calibration
Several pure molten salts are used to calibrate the density measurement set-up before the
actual density measurement All the density values decrease as function of temperature in the
liquid state and follow the same linear equations as described in eq 4 The experimental values
at 350oC for KNO3 NaNO3 and LiNO3 are selected to compare with the literature data at the
same temperature The results are shown in Table 68 Based on the comparison of the literature
data and the experimental data the variation of density for molten nitrate salt is within in 4
Table 68 Calibration of density measurements with different pure nitrate salts
Sample Literature density Experimental density
gcm3 gcm
3
LiNO3 1727 1701
NaNO3 2066 2144
KNO3 1860 1855
632 Results and discussions
The density result of the salt as function of temperature is plotted for all the salts in Figure
621 and Figure 622 It is observed that the temperature dependence of density above the
melting point is different from that in solid state As known in solid state the density of salt has
an exponential relation with temperature while in these liquid cases the density values have
linearly dependence with temperature The stable variation as function of temperature allows the
extrapolation of density at even higher temperature The regression analysis is performed to get
the coefficient used for describing eq 4 and the results for the coefficients are shown in
87
Table69 [78-80] It is observed that the change of composition is implied on the coefficient A
which indicates the initial point at 150oC The temperature dependence coefficient B doesn‟t
change much with composition which may be mainly affected by the group of anion and cation
Table 69 Coefficient A and B for density determination of salt 1-salt 9
Salt No System A Btimes10
3
(gcm3) (gcm
3degC)
1 LiNO3-NaNO3-KNO3 2032 0493
2 NaNO3- NaNO2- KNO3 2081 0570
3 LiNO3- NaNO3- KNO3-MgKN 2055 0526
4 LiNO3- NaNO3- KNO3- NaNO2 2033 0520
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 2018 0485
6 LiNO3-NaNO3-KNO3-KNO2 2060 0554
7 LiNO3-KNO3-NaNO2-KNO2 2048 0554
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 2044 0524
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 2060 0566
Figure 621 The densities of the salt 1-salt 5 as function of temperature
88
In figure 621 all the density values are clustered around 198gcm3 at 150
oC to
186gcm3 at high temperature end and the deviation of density between all the mixtures is within
in 0047g cm3 Among all the salt mixtures the NaNO3-NaNO2-KNO3 ternary system
demonstrates the highest density value throughout the studied temperature range and LiNO3-
NaNO3-KNO3 ternary system LiNO3- NaNO3-KNO3-NaNO2 quaternary system and LiNO3-
NaNO3-KNO3-NaNO2-KNO2 quinary system show densities at the bottom side of Fig 621 For
salt 2 which doesn‟t contain any lithium nitrate the density at every selected temperature spot
is obviously higher than that of salt 1 4 and 5 which have large amount of lithium nitrate
Moreover the salt 3 which contains the relatively small amount of lithium nitrate stays in
between of salt 1 and salt 2 This comparison illustrates that the addition of lithium nitrate has
an offsetting effect on density for molten salt and it is consistent with previous literature reports
[81] The four systems presented in figure 622 also show even closer density values in the
studied temperature range Similarly salt 6 which contains the least lithium nitrate has the
largest density Salt 7 and salt 8 have almost same composition for the three dominating
components as a result of that the density curves for both mixtures are determined by the same
regression coefficient A and B Moreover the larger amount of lithium nitrate involved in these
two salt mixtures contributes to the lower density given in figure622 which further verifies the
significantly offsetting effect of lithium nitrate on density
89
Figure 622 The densities of the salt 6-salt 9 as function of temperature
The salt mixtures with maximum and minimum amount of lithium nitrate were plotted and
compared with equimolar NaNO3-KNO3 binary system and pure KNO3 salt in Fig623 [82 83]
It is observed that the NaNO3-KNO3 binary system has very similar density value to that of salt
2 because of the analogous type and composition of component in both salts The density of
pure KNO3 is slightly lower than the binary salt mixture which indicates the density of NaNO3 is
close to but higher than KNO3 in the studied temperature range Salt 1 shows the lowest density
in Fig623 due to the offsetting effect on density caused by lithium nitrate which has been
discussed above
90
Figure 623 Density of the salt 1 salt 2 as function of temperature compared to the
equimolar NaNO3-KNO3 binary system and pure KNO3
64 Thermal energy storage density of molten salts
The energy density which is considered as one of the most significant parameters of TES
application can be evaluated by calculation based on the measured density heat capacity and
working temperature range The equation of the thermal energy storage density (E) at working
temperature of 500oC is expressed in equation 111
E = Cp (500-Tm) [111]
Where Cp and are extrapolated heat capacity and density at 500oC respectively Tm is
melting point for salt mixture The extrapolation of density and heat capacity is based on the
linear temperature dependence for both parameters in molten state and the values are shown in
Table 610
91
Table 610 Extrapolated value of density and heat capacity at 500oC of salt 1-salt 9
Salt
No System
Density Heat Capacity
(gmL) (JgK)
1 LiNO3-NaNO3-KNO3 1785 170
2 NaNO3- NaNO2- KNO3 1796 168
3 LiNO3-NaNO3-KNO3-MgK 1773 155
4 LiNO3- NaNO3- KNO3- NaNO2 1792 166
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1796 170
6 LiNO3-NaNO3-KNO3-KNO2 1783 163
7 LiNO3-KNO3-NaNO2-KNO2 1771 167
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1782 168
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 1777 170
The calculated energy density for each salt is given in Table 611 compared with that of
solar salt (NaNO3-KNO3) All the new synthesized salt mixtures have significantly higher energy
density than solar salt and salt 3 shows the highest energy density among the new salts
Although salt 1 has higher heat capacity and good melting point the energy density is still the
lowest among new salt mixtures given by the effect of low density The conclusion can be drawn
from these observations that the energy density is a property affected by multiple parameters and
every part plays an important role in determining the efficiency of energy storage of salt
mixtures
92
Table 611 Energy density of salt 1-salt 9 compare to solar salt
The gravimetric storage density of new molten salts are listed in Table 612 and compared
with those different storage systems in fig 624 It is found that in the parabolic trough working
temperature range the gravimetric storage densities of new molten salts are located on the higher
side Even though some reported sensible energy storage liquids have larger gravimetric density
values than the new salts the maximum working temperatures reveal the instable working
condition at 500oC Taking conversion efficiency thermal stability and gravimetric storage
density into considerations the new molten salts are the most suitable choices of the sensible
heat storage for parabolic trough application
Salt No System Energy Density
500degC (MJm3)
0 NaNO3- KNO3 756
1 LiNO3-NaNO3-KNO3 1162
2 NaNO3- NaNO2- KNO3 1135
3 LiNO3-NaNO
3-KNO
3-MgKN 1099
4 LiNO3- NaNO
3- KNO
3- NaNO
2 1189
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1232
6 LiNO3-NaNO3-KNO3-KNO2 1174
7 LiNO3-KNO3-NaNO2-KNO2 1183
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1192
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 1242
93
Fig 624 Gravimetric storage density comparison of different energy storage systems as
function of temperature
Table 612 Gravimetric storage densities for solar salt and new molten salts
Salt
No System
Gravimetric Storage Density
500degC (kJkg)
0 NaNO3- KNO3 404
1 LiNO3-NaNO3-KNO3 560
2 NaNO3- NaNO2- KNO3 533
3 LiNO3-NaNO
3-KNO
3-MgKN 575
4 LiNO3- NaNO
3- KNO
3- NaNO
2 612
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 595
6 LiNO3-NaNO3-KNO3-KNO2 594
7 LiNO3-KNO3-NaNO2-KNO2 604
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 610
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 649
94
CHAPTER 7
CONCLUSION
The melting points of new molten salts were experimentally determined using DSC
Different from metals the melting point was chosen as the peak temperature rather than onset
temperature of the endothermic peak due to the low thermal conductivity and broad phase
transition range of the molten nitride salt mixture All of the nine new molten salts have melting
points from 89oC to 124
oC which are much lower than current sodium-potassium binary solar
salt Some systems such as salt No1 No7 and No8 have solid phase transformation observed
from the DSC plots It is found that the phase transformations of salt No 7 and No 8 are mainly
contributed to the KNO3-NaNO2 binary system while the small solid transformation peak of salt
No1 is resulted from the combined effect of the KNO3-LiNO3 eutectic binary system involved in
the ternary salt and another binary system which is composed of the rest components The
heating rate of DSC was revealed as a significant parameter for the any endothermic peak
determination When using lower heating rate the thermal resistance between the studied sample
and the furnace will be minimal and the resolution of peak detection will be enhanced
The heat capacities of all the multi-component salts (1 to 9) were determined using DSC
and found varying from 143 to 161 JgK at 350oC The heat capacity in the liquid state
demonstrates linear increase trend as function of temperature On the basis of that the heat
capacity was extrapolated to parabolic trough operating temperature of 500oC Besides heat
capacity data as function of temperature are fit to polynomial equation and thermodynamic
95
properties like enthalpy entropy and Gibbs energies of the compound as function of temperature
are subsequently deduced
Experimental measurements of density of multi-component systems were conducted as
function of temperature in their liquid state In liquid state the density values decrease linearly
as temperature increases The results of those mixtures were compared to the solar salt and
individual constituent salts The comparison demonstrates that the addition of lithium nitrate
lowers the density which is consistent with the observation that lithium nitrate has the lowest
density among all the individual salts in the studied temperature range On the basis of densities
heat capacities and the melting points energy storage density for all the new salts were
calculated and compared to the binary solar salt Among all the new molten salt systems
LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN quinary system (salt 9) presents the largest thermal
energy storage density as well as the gravimetric density values Moreover the larger thermal
energy storage as well as gravimetric storage densities compared to the solar salt indicate the
better energy storage capacities of new salts for solar power generation systems
96
REFERENCES
[1] JF Manwell JG McGowan and AL Rogers Wind Energy Explained-Theory Design and
Application second edition John Wiley and sons Ltd UK 2009
[2] MJ Pasqualetti Morality space and the power of wind-energy landscapes Geographical
Review 90 2000 381-394
[3] DG Fink and HW Beaty Standard Handbook for Electrical Engineers Eleventh Edition
McGraw-Hill New York 1978
[4] R Bertani Geothermal Energy An Overview on Resources and Potential Proceedings of the
International Conference on National Development of Geothermal Energy Use 2009 Slovakia
[5] TA Volk LP Abrahamson EH White E Neuhauser E Gray C Demeter C Lindsey J
Jarnefeld DJ Aneshansley R Pellerin and S Edick Developing a Willow Biomass Crop
Enterprise for Bioenergy and Bioproducts in the United States Proceedings of Bioenergy
2000 October 15-19 2000 Buffalo New York USA
[6] M Asplund N Grevesse and AJ Sauval The new solar abundances-Part I the
observations Communications in Asteroseismology 147 2006 76-79
[7] DRWilliams Sun Fact Sheet NASA 2004
httpnssdcgsfcnasagovplanetaryfactsheetsunfacthtml
[8] U Herrmann Survey of Thermal Energy Storage for Parabolic Trough Power Plants Journal
of Solar Energy Engineering 124 2002 145-152
[9] Rocket Research Company Chemical energy storage for solar thermal conversion SAND79-
8198 Livermore Sandia National Laboratories 1979
97
[10] A Steinfeld and R Palumbo Solar thermochemical process technology Encyclopedia of
Physical Science and Technology 2001 237-256
[11] EA Fletcher Solar thermal processing a review Journal of Solar Energy Engineering
2001 63-74
[12] R W Bradshaw and Nathan P Siegel Molten Nitrate Salt Development for Thermal
Energy Storage in Parabolic Trough Solar Power Systems of the Energy Sustainability 2008
Conference August 10-14 2008 Jacksonville Florida USA
[13] B Kelly H Price D Brosseau and D Kearney Adopting NitrateNitrite Salt Mixtures as
the Heat Transport Fluid in Parabolic Trough Power Plants Proceedings of the Energy
Sustainability 2007 Conference June 27-30 2007 Long Beach CA
[14] H Reilly and G Kolb Evaluation of Molten Salt Power Tower Technology Based on
Experience at Solar Two SAND2001-3674 Sandia National Laboratories 2001
[15] T Wendelin ldquoParabolic Trough VSHOT Optical Characterization in 2005-2006rdquo NREL
wwwnrelgovdocsfy06osti40024pdf
[16] RB Diver C Andraka S Rawlinson V Goldberg and G Thomas The Advanced Dish
Development System Project ASME Proceedings of Solar Forum 2001 Washington DC
[17] S D Odeh G L Morrison and M Behnia Modelling of parabolic trough direct steam
generation solar collectors Solar Energy 62 1998 396-406
[18] V Heinzel H Kungle and M Simon Simulation of a parabolic trough collector ISES
Solar World Congress Harare Zimbabwe 1-10
[19] S D Odeh G L Morrison and M Behnia Modeling of Parabolic Trough Direct
Generation Solar Collectors Solar Energy 62 1998 395-406
[20] Ezzat Optimum Working Fluids for Solar Powered Rankine Cycle Cooling of Buildings
Solar energy 25 1980 235-241
98
[21] R G Reddy Ionic Liquids How well do we know them editorial Journal of Phase
Equilibria and Diffusion 27 2006 210-211
[22] M Zhang and R G Reddy Application of [C4min][Tf2N] Ionic Liquid as Thermal
Storage and Heat Transfer Fluids editor J Weidner ECS Transactions 2 (28) 2007 27-32
[23] M Zhang and R G Reddy Evaluation of Ionic Liquids as Heat Transfer Materials in
Thermal Storage Systems Energy Energy Materials editors F Dogan M Awano D Singh
and B Tuttle ASM International Materials Park Ohio USA MSampT‟07 2007 151-160
[24] R G Reddy Novel Applications of Ionic Liquids in Materials Processing Advanced
Structural and Functional Materials Design 2008 Journal of Physics Conference Series (JPCS)
165 2009 1-6
[25] RW Bradshaw and DE Meeker High-temperature stability of ternary nitrate molten
salts for solar thermal energy systems Solar Energy Materials 21 1990 51-60
[26] AS Trunin Designing and investigations of salt systems for solar energy utilization
Utilization of sun and other radiation sources in materials research Kiev Naukova Dumka 1983
p 228-38
[27] D J Rogers and G J Janz Melting-crystallization and premelting properties of sodium
nitrate-potassium nitrate Enthalpies and heat capacities Journal of Chemical and Engineering
Data 27 1982 424-428
[28] D Kearney U Herrmann P Nava and B Kelly Assessment of a molten salt heat transfer
fluid in a parabolic trough solar field Journal of Solar Energy Engineering 125 2003 170-176
[29] Q Peng J Ding X Wei J Yang and X Yang The preparation and properties of multi-
component molten salts Applied Energy 87 2010 2812-2817
[30] E M Levin C R Robbins and H F McMordie Phase Diagrams for Ceramists American
Ceramic Society 1964
[31] J C Oxley J L Smith E Rogers and M Yu Ammonium nitrate thermal stability and
explosivity modifiers Thermochimica Acta 384 2002 23-45
99
[32] LG Marianowski and HC Maru Latent heat thermal energy storage systems above
4508oC Proceedings of 12th intersociety energy conversion engineering conference 1977 55-
66
[33] HC Maru JF Dullea A Kardas L Paul LG Marianowski E Ong et al Molten salts
energy storage systems Chicago Final Report of the Institute of Gas Technology 1978
[34] WM Philips and JW Stears Advanced latent heat of fusion thermal energy storage for
solar power stations Proceedings of 20th intersociety energy conversion engineering conference
2 1985 384-391
[35] KE Mayo Heat source systems USA Patent 3605720 1971
[36] JI Eichelberger and HD Gillman Investigation of metal fluoride thermal energy storage
material Proceedings of 12th intersociety energy conversion engineering conference 1977 567-
574
[37] GR Heidenreich and MB Parekh Thermal energy storage for organic Rankine cycle solar
dynamic space power systems Proceedings of 21st intersociety energy conversion engineering
conference 2 1986 791-797
[38] IK Garkushin AC Trunin TT Miftakhov and MA Dibirov Salt heat storage
composition USSR Patent 1036734 1983
[39] W M Philips and J W Stears Advanced latent heat of fusion thermal energy storage for
solar power stations In Proceedings of 20th intersociety energy conversion engineering
conference 2 1985 384-391
[40] Y Takahashi M Kamimoto Y Abe R Sakamoto K Kanari and T Ozawa Investigation
of latent heat-thermal energy storage materials IV Thermoanalitical evaluation of binary eutectic
mixtures of NaOH with LiOH or KOH Thermochim Acta 121 1987 193-202
[41] C E Birchenall and A F Riechman Heat storage in eutectic alloys Metall Trans A
11A(8) 1980 1415-1420
100
[42] Y Takahashi R Sakamoto and M Kamimoto Heat capacities and latent heats of LiNO3
NaNO3 and KNO3 International Journal of Thermophysics 9(6) 1988 1081-1090
[43] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate Mixtures
Journal of Chemical Engineering Data 8(3) 1963 469
[44] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical Engineering Data 6 (4) 1961 493
[45] GF Petersen WA Ewing and G P Smith Densities of Some Salt Mixtures Journal of
Chemical Engineering Data 6 (4) 1961 540
[46] G J Janz and M R Lorenz Precise Measurement of Density and Surface Tension at
Temperatures up to 1000degC in One Apparatus Review of Scientific Instruments 31 (1) 1960
18-23
[47] G J Janz C B Allen N P Bansal R M Murphy and R P Tomkins Physical Properties
Data Compilations Relevant to Energy Storage II Molten Salts Data on Single and Multi-
Component Salt Systems National Bureau of Standards NSRDS-NBS 61 Part II April 1979
[48] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation Equations
for Critically Evaluated Density Surface Tension Electrical Conductance and Viscosity Data
Journal of Physical and Chemical Reference Data 17 1988 2
[49] A T Ward and G J Janz Molten Carbonate Electrolytes Electiral Conductance Density
and Surface Tension of Binary and Ternary Eleclrochimica Acta 10 1965 849-857
[50] Y Takahashi R Sakamoto and MKamimoto Heat Capacities and Latent Heat of LiNO3
NaNO3 amp KNO3 International Journal of Thermophysics 9 1998 1081-1090
[51] R W Carling Heat capacities of NaNO3 and KNO3 up to 800 K Thermochimica Acta 60
1983 265-275
[52] Y Takahashi Latent heat measurement by DSC with sapphire as standard material
Thermochim Acta 88(1) 1985 199-204
101
[53] GW Hohne W Hemminger and HJ Flammersheim Differential Scanning Calorimetry
Springer-Verlag Berlin 1996
[54] W Hemminger and G Hohne Calorimetry Fundamentals and Practice Verlag Weinheim
1984
[55] M Merzlyakov and C Schick Thermal conductivity from dynamic response of DSC
Thermochimica Acta 377 2001 183-191
[56] T Kousksou A Jamil S Gibout and Y Zeraouli Thermal analysis of phase change
emulsion Journal of Thermal Analysis and Calorimetry 96 2009 841-852
[57] A Jamil T Kousksou K El Omari Y Zeraouli and Y Le Guer Heat transfer in salt
solutions enclosed in DSC cells Thermochimica Acta 507-508 2010 15-20
[58] MJ Richardson Quantitative aspects of differential scanning calorimetry Thermochimica
Acta 300 1997 15-28
[59] S Rudtsch Uncertainty of heat capacity measurements with differential scanning
calorimeters Thermochimica Acta 382 2002 17-25
[60] M J Maeso and J Largo The phase diagram of LiNO3-NaNO3 and LiNO3-KNO3 the
behavior of liquid mixtures Thermochimica Acta 223 (1993) 145-156
[61] O J Kleppa A new twin high-temperature reaction calorimeter The heats of mixing in
liquid sodium-potassium nitrates Journal of Physical Chemistry 64(12) (1960) 1937-1940
[62] G W H Hhne H K Cammenga W Eysel E Gmelin and W Hemminger The
Temperature Calibration of Scanning Calorimeters Thermochimica Acta 160 1990 1-12
[63] L B Pankratz Thermodynamic Properties of Carbides Nitrides and Other Selected
Substances U S Bureau of Mines Bulletin 696 1994
[64] M Zhang and R G Reddy Thermodynamic properties of C4mim[Tf2N] ionic liquids 0 2
2010 71-76
102
[65] D Mantha T Wang and R G Reddy Thermodynamic Modeling of Eutectic Point in the
LiNO3-NaNO3-KNO3 Ternary System Journal of Phase Equilibria and Diffusion 2011
(accepted)
[66] R G Reddy T Wang and D Mantha Determination of thermodynamic properties of
2KNO3Mg(NO3)2 Thermochimica Acta 2011 (submitted)
[67] T Wang D Mantha and R G Reddy Thermal stability of new LiNO3-NaNO3-KNO3
ternary salt for thermal energy storage system (in preparation)
[68] G D Carvalho E Frollini and W N D Santos Thermal conductivity of polymers by hot-
wire method J Appl Poly Sci 62 (1996) 2281-2285
[69] H Bloom A Doroszkowski and S B Tricklebank Molten salt mixtures IX The thermal
conductivities of molten nitrate systems Aus J Chem 18(8) (1965) 1171-1176
[70] A G Turnbull Thermal conductivity of molten salts Aus J Appl Sci 12 (1961) 30-41
[71] L R White and H T Davis Thermal conductivity of molten alkali nitrates J Chem Phys
47(1967) 5433-5439
[72] M V Peralta-Martinez M J Assael M J Dix L Karagiannidis and W A Wakeham A
Novel Instrument for the Measurement of the Thermal Conductivity of Molten Metal Part1
Instrument‟s Description Int J Thermophysics 27 (2006) 353-375
[73] Y Tada M Harada M Tanlgakl and W Eguchl Laser Flash Method for Measuring
Thermal Conductivity of Liquids Application to Molten Salts Industrial and Engineering
Chemistry Fundamentals 20 1981 333- 336
[74] M V Smirnov V A Khokhlov and E S Filatov Thermal conductivity of molten alkali
halides and their mixtures Electrochimica Acta 32 (1986) 1019-1026
[75] E Marti E Kaisersberger and W D Emmerich NEW ASPECTS OF THERMAL
ANALYSIS Part I Resolution of DSC and means for its optimization Journal of Thermal
Analysis and Calorimetry 77 2004 905-934
103
[76] E Marti E Kaisersberger G Kaiser and WY Ma Netzsch Annual 2000
bdquoThermoanalytical Characterization of Pharmaceuticals‟ Netzsch-Geraumltebau GmbH D-95100
SelbBavaria
[77] P J van Ekeren C M Holl and A J Witteveen A comparative test of differential
scanning calorimeters Journal of Thermal Analysis and Calorimetry 49 1997 1105-1114
[78] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation
Equations for Critically Evaluated Density Surface Tension Electrical Conductance and
Viscosity Data Journal of Physical and Chemical Reference Data 17 1988 1
[79] G F Petersen W A Ewing and G P Smith ldquoDensities of Some Salt Mixturesrdquo Journal of
Chemical and Engineering Data 6 1961 540
[80] P M Nasch and S G Steinemann Density and Thermal Expansion of Molten Manganese
Iron Nickel Copper Aluminum and Tin by Means of the Gamma-Ray Attenuation Technique
Physics and Chemistry of Liquids 29 1995 43-58
[81] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical and Engineering Data 6 1961 493-496
[82] D A Nissen Thermophysical Properties of the Equimolar Mixture NaNO3-KNO3 from
300degC to 600degC Journal of Chemical and Engineering Data 27 1982 269-273
[83] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate
Mixtures Journal of Chemical and Engineering Data 8 1963 469
104
APPENDIX
Appendix A
Table A1 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in solid state
(29815-40315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 342 1290 417 -025
299 027 008 000 343 1317 426 -026
300 059 018 000 344 1345 436 -027
301 091 028 000 345 1372 445 -028
302 123 037 000 346 1399 455 -029
303 154 047 000 347 1427 464 -031
304 186 056 000 348 1454 474 -032
305 217 066 000 349 1481 483 -033
306 248 076 000 350 1508 493 -035
307 279 085 000 351 1535 503 -036
308 310 095 -001 352 1562 512 -038
309 340 104 -001 353 1589 522 -039
310 371 114 -001 354 1616 532 -041
311 401 123 -001 355 1643 541 -042
312 432 133 -002 356 1670 551 -044
313 462 142 -002 357 1697 561 -045
314 492 152 -002 358 1724 570 -047
315 521 161 -003 359 1751 580 -048
316 551 171 -003 360 1777 590 -050
317 581 180 -004 361 1804 600 -052
318 610 190 -004 362 1831 610 -053
319 640 199 -005 363 1858 619 -055
320 669 209 -005 364 1885 629 -057
105
321 698 218 -006 365 1911 639 -059
322 727 228 -007 366 1938 649 -060
323 756 237 -007 367 1965 659 -062
324 785 246 -008 368 1992 669 -064
325 814 256 -009 369 2018 679 -066
326 842 265 -009 370 2045 689 -068
327 871 275 -010 371 2072 699 -070
328 899 284 -011 372 2098 709 -072
329 928 294 -012 373 2125 719 -074
330 956 303 -012 374 2152 729 -076
331 984 313 -013 375 2179 739 -078
332 1012 322 -014 376 2205 750 -080
333 1041 331 -015 377 2232 760 -082
334 1069 341 -016 378 2259 770 -084
335 1096 350 -017 379 2286 780 -086
336 1124 360 -018 380 2312 791 -088
337 1152 369 -019 381 2339 801 -090
338 1180 379 -020 382 2366 811 -093
339 1207 388 -021 383 2393 822 -095
340 1235 398 -022 384 2420 832 -097
341 1263 407 -023 38415 2424 834 -097
Table A2 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in liquid state
(40315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
40315 4287 1565 -163 514 7070 2838 -796
404 4310 1575 -167 515 7094 2850 -803
405 4337 1585 -171 516 7117 2863 -810
406 4363 1596 -175 517 7141 2875 -817
407 4390 1607 -180 518 7165 2887 -824
408 4417 1618 -184 519 7188 2899 -831
409 4443 1629 -189 520 7212 2911 -839
410 4470 1640 -193 521 7235 2924 -846
411 4496 1651 -197 522 7259 2936 -853
412 4523 1662 -202 523 7282 2948 -860
106
413 4549 1672 -206 524 7306 2960 -868
414 4576 1683 -211 525 7329 2973 -875
415 4602 1694 -216 526 7352 2985 -882
416 4629 1705 -220 527 7376 2997 -890
417 4655 1716 -225 528 7399 3010 -897
418 4681 1727 -230 529 7422 3022 -904
419 4708 1738 -234 530 7446 3034 -912
420 4734 1749 -239 531 7469 3047 -919
421 4760 1760 -244 532 7492 3059 -927
422 4786 1771 -249 533 7516 3071 -934
423 4813 1782 -253 534 7539 3084 -942
424 4839 1793 -258 535 7562 3096 -949
425 4865 1804 -263 536 7585 3109 -957
426 4891 1816 -268 537 7608 3121 -965
427 4917 1827 -273 538 7632 3134 -972
428 4943 1838 -278 539 7655 3146 -980
429 4969 1849 -283 540 7678 3158 -988
430 4995 1860 -288 541 7701 3171 -995
431 5021 1871 -293 542 7724 3183 -1003
432 5046 1882 -298 543 7747 3196 -1011
433 5072 1894 -303 544 7770 3208 -1018
434 5098 1905 -308 545 7793 3221 -1026
435 5124 1916 -313 546 7816 3233 -1034
436 5149 1927 -318 547 7839 3246 -1042
437 5175 1938 -323 548 7862 3259 -1050
438 5201 1950 -328 549 7885 3271 -1058
439 5226 1961 -334 550 7908 3284 -1066
440 5252 1972 -339 551 7931 3296 -1073
441 5278 1983 -344 552 7953 3309 -1081
442 5303 1995 -349 553 7976 3322 -1089
443 5329 2006 -355 554 7999 3334 -1097
444 5354 2017 -360 555 8022 3347 -1105
445 5380 2028 -365 556 8045 3359 -1113
446 5405 2040 -371 557 8067 3372 -1121
447 5430 2051 -376 558 8090 3385 -1130
448 5456 2062 -382 559 8113 3398 -1138
449 5481 2074 -387 560 8136 3410 -1146
450 5506 2085 -393 561 8158 3423 -1154
451 5532 2097 -398 562 8181 3436 -1162
452 5557 2108 -404 563 8204 3448 -1170
107
453 5582 2119 -409 564 8226 3461 -1178
454 5607 2131 -415 565 8249 3474 -1187
455 5633 2142 -421 566 8271 3487 -1195
456 5658 2154 -426 567 8294 3499 -1203
457 5683 2165 -432 568 8317 3512 -1212
458 5708 2177 -438 569 8339 3525 -1220
459 5733 2188 -443 570 8362 3538 -1228
460 5758 2200 -449 571 8384 3551 -1237
461 5783 2211 -455 572 8407 3564 -1245
462 5808 2223 -461 573 8429 3576 -1253
463 5833 2234 -466 574 8452 3589 -1262
464 5858 2246 -472 575 8474 3602 -1270
465 5883 2257 -478 576 8496 3615 -1279
466 5907 2269 -484 577 8519 3628 -1287
467 5932 2280 -490 578 8541 3641 -1296
468 5957 2292 -496 579 8564 3654 -1304
469 5982 2304 -502 580 8586 3667 -1313
470 6007 2315 -508 581 8608 3680 -1322
471 6031 2327 -514 582 8631 3693 -1330
472 6056 2339 -520 583 8653 3706 -1339
473 6081 2350 -526 584 8675 3719 -1348
474 6105 2362 -532 585 8697 3732 -1356
475 6130 2373 -538 586 8720 3745 -1365
476 6155 2385 -544 587 8742 3758 -1374
477 6179 2397 -551 588 8764 3771 -1382
478 6204 2409 -557 589 8786 3784 -1391
479 6228 2420 -563 590 8808 3797 -1400
480 6253 2432 -569 591 8831 3810 -1409
481 6277 2444 -575 592 8853 3823 -1418
482 6301 2456 -582 593 8875 3836 -1426
483 6326 2467 -588 594 8897 3849 -1435
484 6350 2479 -594 595 8919 3863 -1444
485 6375 2491 -601 596 8941 3876 -1453
486 6399 2503 -607 597 8963 3889 -1462
487 6423 2515 -614 598 8985 3902 -1471
488 6448 2526 -620 599 9007 3915 -1480
489 6472 2538 -626 600 9029 3928 -1489
490 6496 2550 -633 601 9051 3942 -1498
491 6520 2562 -639 602 9073 3955 -1507
492 6544 2574 -646 603 9095 3968 -1516
108
493 6569 2586 -653 604 9117 3981 -1525
494 6593 2598 -659 605 9139 3994 -1535
495 6617 2610 -666 606 9161 4008 -1544
496 6641 2621 -672 607 9183 4021 -1553
497 6665 2633 -679 608 9205 4034 -1562
498 6689 2645 -686 609 9226 4048 -1571
499 6713 2657 -692 610 9248 4061 -1581
500 6737 2669 -699 611 9270 4074 -1590
501 6761 2681 -706 612 9292 4088 -1599
502 6785 2693 -713 613 9314 4101 -1608
503 6809 2705 -719 614 9335 4114 -1618
504 6833 2717 -726 615 9357 4128 -1627
505 6856 2729 -733 616 9379 4141 -1636
506 6880 2741 -740 617 9401 4154 -1646
507 6904 2754 -747 618 9422 4168 -1655
508 6928 2766 -754 619 9444 4181 -1665
509 6952 2778 -761 620 9466 4195 -1674
510 6975 2790 -768 621 9487 4208 -1684
511 6999 2802 -775 622 9509 4222 -1693
512 7023 2814 -782 623 9531 4235 -1703
513 7047 2826 -789 62315 9534 4237 -1704
109
Appendix B
Table B1 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(29815-39215K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 347 1233 382 -046
299 022 006 000 348 1258 390 -048
300 049 014 -001 349 1283 398 -049
301 075 022 -001 350 1307 406 -051
302 101 029 -001 351 1332 415 -053
303 127 037 -002 352 1356 423 -054
304 153 044 -002 353 1381 431 -056
305 179 052 -003 354 1405 440 -058
306 205 059 -003 355 1430 448 -060
307 230 067 -004 356 1455 456 -061
308 256 075 -004 357 1479 465 -063
309 282 082 -005 358 1504 473 -065
310 308 090 -005 359 1528 482 -067
311 333 098 -006 360 1553 490 -069
312 359 105 -007 361 1577 498 -071
313 384 113 -007 362 1602 507 -073
314 410 121 -008 363 1626 515 -075
315 435 128 -009 364 1651 524 -077
316 461 136 -010 365 1675 533 -079
317 486 144 -010 366 1700 541 -081
318 511 151 -011 367 1724 550 -083
319 537 159 -012 368 1749 558 -085
320 562 167 -013 369 1773 567 -087
321 587 175 -014 370 1798 576 -089
322 612 182 -015 371 1822 584 -092
323 637 190 -016 372 1847 593 -094
324 663 198 -017 373 1871 602 -096
325 688 206 -018 374 1896 611 -098
326 713 214 -019 375 1920 620 -100
327 738 222 -020 376 1945 628 -103
328 763 229 -021 377 1969 637 -105
329 788 237 -022 378 1994 646 -107
110
330 813 245 -023 379 2018 655 -110
331 838 253 -024 380 2043 664 -112
332 863 261 -025 381 2068 673 -115
333 887 269 -027 382 2092 682 -117
334 912 277 -028 383 2117 691 -120
335 937 285 -029 384 2141 700 -122
336 962 293 -030 385 2166 709 -125
337 987 301 -032 386 2191 718 -127
338 1011 309 -033 387 2215 727 -130
339 1036 317 -034 388 2240 737 -132
340 1061 325 -036 389 2265 746 -135
341 1086 333 -037 390 2289 755 -138
342 1110 341 -039 391 2314 764 -140
343 1135 349 -040 392 2339 774 -143
344 1160 357 -042 39215 2342 775 -144
345 1184 365 -043
Table B2 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(41315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
414 3280 1149 -209 520 5608 2235 -682
415 3302 1158 -212 521 5630 2246 -687
416 3325 1167 -216 522 5651 2257 -693
417 3348 1177 -219 523 5672 2268 -698
418 3370 1186 -223 524 5694 2279 -704
419 3393 1196 -226 525 5715 2290 -710
420 3416 1205 -229 526 5736 2302 -716
421 3438 1215 -233 527 5757 2313 -721
422 3461 1224 -236 528 5779 2324 -727
423 3483 1234 -240 529 5800 2335 -733
424 3506 1243 -243 530 5821 2347 -739
425 3529 1253 -247 531 5842 2358 -745
426 3551 1263 -250 532 5864 2369 -750
427 3574 1272 -254 533 5885 2380 -756
428 3596 1282 -257 534 5906 2392 -762
429 3619 1291 -261 535 5927 2403 -768
111
430 3641 1301 -265 536 5948 2414 -774
431 3663 1311 -268 537 5970 2426 -780
432 3686 1320 -272 538 5991 2437 -786
433 3708 1330 -276 539 6012 2449 -792
434 3731 1340 -279 540 6033 2460 -798
435 3753 1350 -283 541 6054 2471 -804
436 3775 1359 -287 542 6075 2483 -810
437 3798 1369 -291 543 6096 2494 -816
438 3820 1379 -294 544 6118 2506 -822
439 3842 1389 -298 545 6139 2517 -828
440 3865 1398 -302 546 6160 2529 -835
441 3887 1408 -306 547 6181 2540 -841
442 3909 1418 -310 548 6202 2552 -847
443 3932 1428 -314 549 6223 2563 -853
444 3954 1438 -318 550 6244 2575 -859
445 3976 1448 -322 551 6265 2586 -866
446 3998 1458 -326 552 6286 2598 -872
447 4021 1468 -330 553 6307 2610 -878
448 4043 1477 -334 554 6328 2621 -884
449 4065 1487 -338 555 6349 2633 -891
450 4087 1497 -342 556 6370 2645 -897
451 4109 1507 -346 557 6391 2656 -904
452 4131 1517 -350 558 6412 2668 -910
453 4154 1527 -354 559 6433 2680 -916
454 4176 1537 -358 560 6454 2691 -923
455 4198 1547 -363 561 6475 2703 -929
456 4220 1557 -367 562 6496 2715 -936
457 4242 1568 -371 563 6517 2727 -942
458 4264 1578 -375 564 6538 2738 -949
459 4286 1588 -380 565 6559 2750 -955
460 4308 1598 -384 566 6580 2762 -962
461 4330 1608 -388 567 6600 2774 -969
462 4352 1618 -393 568 6621 2786 -975
463 4374 1628 -397 569 6642 2798 -982
464 4396 1639 -401 570 6663 2810 -988
465 4418 1649 -406 571 6684 2821 -995
466 4440 1659 -410 572 6705 2833 -1002
467 4462 1669 -415 573 6726 2845 -1009
468 4484 1680 -419 574 6747 2857 -1015
469 4506 1690 -424 575 6767 2869 -1022
112
470 4528 1700 -428 576 6788 2881 -1029
471 4550 1710 -433 577 6809 2893 -1036
472 4572 1721 -437 578 6830 2905 -1042
473 4593 1731 -442 579 6851 2917 -1049
474 4615 1741 -446 580 6871 2929 -1056
475 4637 1752 -451 581 6892 2941 -1063
476 4659 1762 -456 582 6913 2953 -1070
477 4681 1773 -460 583 6934 2966 -1077
478 4703 1783 -465 584 6954 2978 -1084
479 4724 1793 -470 585 6975 2990 -1091
480 4746 1804 -474 586 6996 3002 -1098
481 4768 1814 -479 587 7017 3014 -1105
482 4790 1825 -484 588 7037 3026 -1112
483 4812 1835 -489 589 7058 3038 -1119
484 4833 1846 -494 590 7079 3051 -1126
485 4855 1856 -498 591 7100 3063 -1133
486 4877 1867 -503 592 7120 3075 -1140
487 4898 1877 -508 593 7141 3087 -1147
488 4920 1888 -513 594 7162 3100 -1154
489 4942 1899 -518 595 7182 3112 -1162
490 4963 1909 -523 596 7203 3124 -1169
491 4985 1920 -528 597 7224 3137 -1176
492 5007 1930 -533 598 7244 3149 -1183
493 5028 1941 -538 599 7265 3161 -1190
494 5050 1952 -543 600 7285 3174 -1198
495 5072 1962 -548 601 7306 3186 -1205
496 5093 1973 -553 602 7327 3198 -1212
497 5115 1984 -558 603 7347 3211 -1220
498 5136 1995 -563 604 7368 3223 -1227
499 5158 2005 -568 605 7389 3236 -1234
500 5180 2016 -574 606 7409 3248 -1242
501 5201 2027 -579 607 7430 3261 -1249
502 5223 2038 -584 608 7450 3273 -1257
503 5244 2049 -589 609 7471 3286 -1264
504 5266 2059 -595 610 7491 3298 -1272
505 5287 2070 -600 611 7512 3311 -1279
506 5309 2081 -605 612 7532 3323 -1287
507 5330 2092 -610 613 7553 3336 -1294
508 5352 2103 -616 614 7573 3348 -1302
509 5373 2114 -621 615 7594 3361 -1309
113
510 5394 2125 -627 616 7615 3374 -1317
511 5416 2136 -632 617 7635 3386 -1325
512 5437 2147 -637 618 7656 3399 -1332
513 5459 2158 -643 619 7676 3412 -1340
514 5480 2169 -648 620 7696 3424 -1348
515 5502 2180 -654 621 7717 3437 -1355
516 5523 2191 -659 622 7737 3450 -1363
517 5544 2202 -665 623 7758 3462 -1371
518 5566 2213 -670 62315 7761 3464 -1372
114
Appendix C
Table C1 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in solid
state (29815-36415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 333 1937 611 -034
299 048 014 000 334 1992 629 -036
300 104 031 000 335 2047 647 -038
301 160 048 000 336 2102 666 -040
302 216 065 000 337 2156 684 -042
303 272 082 -001 338 2211 703 -045
304 329 099 -001 339 2266 721 -047
305 385 116 -001 340 2321 740 -049
306 441 133 -002 341 2375 758 -052
307 496 150 -002 342 2430 777 -054
308 552 167 -003 343 2485 796 -056
309 608 185 -003 344 2539 815 -059
310 664 202 -004 345 2594 833 -062
311 720 219 -005 346 2648 852 -064
312 776 236 -006 347 2703 871 -067
313 831 254 -006 348 2757 890 -070
314 887 271 -007 349 2812 909 -072
315 942 289 -008 350 2866 928 -075
316 998 306 -009 351 2921 947 -078
317 1054 324 -010 352 2975 966 -081
318 1109 341 -011 353 3029 985 -084
319 1164 359 -012 354 3084 1004 -087
320 1220 377 -014 355 3138 1024 -090
321 1275 395 -015 356 3192 1043 -094
322 1331 412 -016 357 3246 1062 -097
323 1386 430 -018 358 3300 1082 -100
324 1441 448 -019 359 3355 1101 -103
325 1496 466 -020 360 3409 1120 -107
326 1552 484 -022 361 3463 1140 -110
327 1607 502 -024 362 3517 1159 -114
328 1662 520 -025 363 3571 1179 -117
329 1717 538 -027 364 3625 1199 -121
115
330 1772 556 -029 36415 3633 1202 -121
331 1827 574 -030
332 1882 593 -032
Table C2 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in liquid
state (42115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
42115 7428 2673 -455 523 11788 4725 -1440
422 7468 2690 -461 524 11827 4745 -1452
423 7515 2710 -468 525 11866 4766 -1464
424 7562 2730 -476 526 11904 4786 -1476
425 7608 2750 -484 527 11943 4807 -1488
426 7655 2770 -491 528 11982 4827 -1500
427 7702 2790 -499 529 12021 4847 -1512
428 7748 2810 -507 530 12059 4868 -1524
429 7795 2830 -514 531 12098 4888 -1536
430 7841 2849 -522 532 12137 4909 -1548
431 7887 2869 -530 533 12175 4929 -1560
432 7933 2889 -538 534 12213 4950 -1572
433 7979 2909 -546 535 12252 4970 -1584
434 8025 2929 -554 536 12290 4991 -1597
435 8071 2949 -562 537 12328 5011 -1609
436 8117 2969 -570 538 12366 5032 -1621
437 8163 2989 -578 539 12404 5052 -1634
438 8208 3009 -586 540 12442 5073 -1646
439 8254 3029 -595 541 12480 5093 -1659
440 8299 3049 -603 542 12518 5114 -1671
441 8345 3069 -611 543 12556 5134 -1684
442 8390 3089 -620 544 12594 5155 -1696
443 8435 3109 -628 545 12632 5175 -1709
444 8480 3129 -636 546 12669 5196 -1721
445 8525 3149 -645 547 12707 5217 -1734
446 8570 3169 -654 548 12745 5237 -1747
116
447 8615 3189 -662 549 12782 5258 -1760
448 8659 3209 -671 550 12820 5278 -1772
449 8704 3229 -679 551 12857 5299 -1785
450 8748 3249 -688 552 12894 5319 -1798
451 8793 3269 -697 553 12932 5340 -1811
452 8837 3289 -706 554 12969 5361 -1824
453 8881 3309 -715 555 13006 5381 -1837
454 8926 3329 -724 556 13043 5402 -1850
455 8970 3349 -732 557 13080 5422 -1863
456 9014 3369 -741 558 13117 5443 -1876
457 9058 3389 -750 559 13154 5464 -1889
458 9102 3409 -760 560 13191 5484 -1902
459 9145 3429 -769 561 13228 5505 -1916
460 9189 3449 -778 562 13264 5526 -1929
461 9233 3469 -787 563 13301 5546 -1942
462 9276 3489 -796 564 13338 5567 -1956
463 9319 3509 -806 565 13374 5588 -1969
464 9363 3529 -815 566 13411 5608 -1982
465 9406 3549 -824 567 13447 5629 -1996
466 9449 3570 -834 568 13484 5650 -2009
467 9492 3590 -843 569 13520 5670 -2023
468 9535 3610 -853 570 13557 5691 -2036
469 9578 3630 -862 571 13593 5712 -2050
470 9621 3650 -872 572 13629 5732 -2063
471 9664 3670 -882 573 13665 5753 -2077
472 9707 3690 -891 574 13701 5774 -2091
473 9749 3710 -901 575 13737 5795 -2104
474 9792 3731 -911 576 13773 5815 -2118
475 9834 3751 -921 577 13809 5836 -2132
476 9877 3771 -930 578 13845 5857 -2146
477 9919 3791 -940 579 13881 5877 -2160
478 9961 3811 -950 580 13917 5898 -2174
479 10004 3831 -960 581 13953 5919 -2188
480 10046 3852 -970 582 13988 5940 -2202
481 10088 3872 -980 583 14024 5960 -2216
482 10130 3892 -990 584 14060 5981 -2230
483 10171 3912 -1001 585 14095 6002 -2244
484 10213 3932 -1011 586 14131 6023 -2258
485 10255 3953 -1021 587 14166 6044 -2272
486 10297 3973 -1031 588 14201 6064 -2286
117
487 10338 3993 -1042 589 14237 6085 -2300
488 10380 4013 -1052 590 14272 6106 -2315
489 10421 4034 -1062 591 14307 6127 -2329
490 10462 4054 -1073 592 14342 6148 -2343
491 10504 4074 -1083 593 14378 6168 -2358
492 10545 4094 -1094 594 14413 6189 -2372
493 10586 4114 -1104 595 14448 6210 -2386
494 10627 4135 -1115 596 14483 6231 -2401
495 10668 4155 -1126 597 14518 6252 -2415
496 10709 4175 -1136 598 14552 6273 -2430
497 10750 4196 -1147 599 14587 6293 -2444
498 10791 4216 -1158 600 14622 6314 -2459
499 10831 4236 -1169 601 14657 6335 -2474
500 10872 4256 -1179 602 14692 6356 -2488
501 10912 4277 -1190 603 14726 6377 -2503
502 10953 4297 -1201 604 14761 6398 -2518
503 10993 4317 -1212 605 14795 6419 -2533
504 11034 4338 -1223 606 14830 6439 -2547
505 11074 4358 -1234 607 14864 6460 -2562
506 11114 4378 -1245 608 14899 6481 -2577
507 11154 4399 -1257 609 14933 6502 -2592
508 11194 4419 -1268 610 14967 6523 -2607
509 11234 4439 -1279 611 15002 6544 -2622
510 11274 4460 -1290 612 15036 6565 -2637
511 11314 4480 -1302 613 15070 6586 -2652
512 11354 4500 -1313 614 15104 6607 -2667
513 11394 4521 -1324 615 15138 6628 -2682
514 11433 4541 -1336 616 15172 6649 -2697
515 11473 4562 -1347 617 15206 6670 -2713
516 11513 4582 -1359 618 15240 6691 -2728
517 11552 4602 -1370 619 15274 6712 -2743
518 11591 4623 -1382 620 15308 6733 -2758
519 11631 4643 -1393 621 15342 6754 -2774
520 11670 4664 -1405 622 15375 6774 -2789
521 11709 4684 -1417 623 15409 6795 -2804
522 11748 4704 -1428 62315 15414 6799 -2807
118
Appendix D
Table D1 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in solid state
(29815-36315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
299 021 006 000 333 867 277 -012
300 047 014 000 334 891 285 -012
301 072 022 000 335 916 293 -013
302 097 029 000 336 940 302 -014
303 122 037 000 337 964 310 -015
304 147 045 000 338 989 318 -016
305 172 053 000 339 1013 327 -017
306 197 060 000 340 1037 335 -018
307 223 068 000 341 1061 343 -019
308 248 076 000 342 1085 352 -019
309 273 084 000 343 1109 360 -020
310 298 092 -001 344 1134 369 -021
311 323 099 -001 345 1158 377 -022
312 348 107 -001 346 1182 385 -024
313 373 115 -001 347 1206 394 -025
314 398 123 -002 348 1230 402 -026
315 423 131 -002 349 1254 411 -027
316 447 139 -002 350 1277 419 -028
317 472 147 -003 351 1301 428 -029
318 497 155 -003 352 1325 436 -030
319 522 163 -003 353 1349 445 -032
320 547 171 -004 354 1373 453 -033
321 572 179 -004 355 1396 462 -034
322 596 187 -005 356 1420 470 -035
323 621 195 -005 357 1444 479 -037
324 646 203 -006 358 1467 487 -038
325 670 211 -006 359 1491 496 -039
326 695 220 -007 360 1514 504 -041
327 720 228 -008 361 1538 513 -042
328 744 236 -008 362 1561 522 -043
329 769 244 -009 363 1584 530 -045
330 793 252 -010 36315 1588 532 -045
119
331 818 260 -010
Table D2 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in liquid
state (38115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
38115 2281 765 -104 503 5639 2242 -594
382 2307 775 -106 504 5664 2255 -600
383 2338 787 -109 505 5689 2267 -606
384 2369 798 -111 506 5713 2280 -611
385 2399 810 -113 507 5738 2292 -617
386 2430 822 -116 508 5763 2305 -623
387 2460 834 -118 509 5787 2317 -629
388 2491 846 -121 510 5812 2330 -634
389 2521 857 -123 511 5836 2342 -640
390 2551 869 -126 512 5861 2355 -646
391 2582 881 -128 513 5885 2367 -652
392 2612 893 -131 514 5910 2380 -658
393 2642 905 -134 515 5934 2392 -664
394 2672 917 -136 516 5959 2405 -670
395 2702 928 -139 517 5983 2417 -676
396 2732 940 -142 518 6007 2430 -682
397 2762 952 -144 519 6032 2443 -688
398 2792 964 -147 520 6056 2455 -694
399 2821 976 -150 521 6080 2468 -700
400 2851 988 -153 522 6104 2480 -706
401 2881 999 -156 523 6128 2493 -712
402 2910 1011 -159 524 6152 2506 -718
403 2940 1023 -162 525 6176 2518 -724
404 2969 1035 -164 526 6200 2531 -731
405 2999 1047 -167 527 6224 2544 -737
406 3028 1059 -170 528 6248 2556 -743
407 3057 1071 -174 529 6272 2569 -749
408 3087 1083 -177 530 6296 2581 -756
120
409 3116 1095 -180 531 6320 2594 -762
410 3145 1107 -183 532 6344 2607 -768
411 3174 1119 -186 533 6368 2619 -775
412 3203 1130 -189 534 6391 2632 -781
413 3232 1142 -192 535 6415 2645 -787
414 3261 1154 -196 536 6439 2657 -794
415 3290 1166 -199 537 6462 2670 -800
416 3319 1178 -202 538 6486 2683 -807
417 3347 1190 -206 539 6510 2696 -813
418 3376 1202 -209 540 6533 2708 -820
419 3405 1214 -212 541 6557 2721 -826
420 3433 1226 -216 542 6580 2734 -833
421 3462 1238 -219 543 6604 2746 -839
422 3490 1250 -223 544 6627 2759 -846
423 3519 1262 -226 545 6650 2772 -853
424 3547 1274 -230 546 6674 2785 -859
425 3575 1286 -233 547 6697 2797 -866
426 3604 1298 -237 548 6720 2810 -873
427 3632 1310 -240 549 6744 2823 -879
428 3660 1322 -244 550 6767 2836 -886
429 3688 1334 -248 551 6790 2848 -893
430 3716 1346 -251 552 6813 2861 -900
431 3744 1358 -255 553 6836 2874 -907
432 3772 1371 -259 554 6860 2887 -913
433 3800 1383 -263 555 6883 2900 -920
434 3828 1395 -267 556 6906 2912 -927
435 3856 1407 -270 557 6929 2925 -934
436 3883 1419 -274 558 6952 2938 -941
437 3911 1431 -278 559 6975 2951 -948
438 3939 1443 -282 560 6998 2964 -955
439 3966 1455 -286 561 7020 2976 -962
440 3994 1467 -290 562 7043 2989 -969
441 4021 1479 -294 563 7066 3002 -976
442 4049 1491 -298 564 7089 3015 -983
443 4076 1504 -302 565 7112 3028 -990
444 4103 1516 -306 566 7134 3041 -997
445 4131 1528 -310 567 7157 3054 -1005
446 4158 1540 -314 568 7180 3066 -1012
447 4185 1552 -319 569 7203 3079 -1019
448 4212 1564 -323 570 7225 3092 -1026
121
449 4240 1576 -327 571 7248 3105 -1033
450 4267 1589 -331 572 7270 3118 -1041
451 4294 1601 -336 573 7293 3131 -1048
452 4321 1613 -340 574 7315 3144 -1055
453 4347 1625 -344 575 7338 3157 -1063
454 4374 1637 -349 576 7360 3170 -1070
455 4401 1650 -353 577 7383 3183 -1077
456 4428 1662 -357 578 7405 3196 -1085
457 4455 1674 -362 579 7428 3208 -1092
458 4481 1686 -366 580 7450 3221 -1100
459 4508 1698 -371 581 7472 3234 -1107
460 4535 1711 -375 582 7494 3247 -1114
461 4561 1723 -380 583 7517 3260 -1122
462 4588 1735 -384 584 7539 3273 -1129
463 4614 1747 -389 585 7561 3286 -1137
464 4641 1760 -394 586 7583 3299 -1145
465 4667 1772 -398 587 7605 3312 -1152
466 4693 1784 -403 588 7628 3325 -1160
467 4720 1796 -408 589 7650 3338 -1167
468 4746 1809 -412 590 7672 3351 -1175
469 4772 1821 -417 591 7694 3364 -1183
470 4798 1833 -422 592 7716 3377 -1191
471 4825 1846 -427 593 7738 3390 -1198
472 4851 1858 -432 594 7760 3403 -1206
473 4877 1870 -437 595 7782 3416 -1214
474 4903 1882 -441 596 7804 3429 -1222
475 4929 1895 -446 597 7825 3442 -1229
476 4955 1907 -451 598 7847 3455 -1237
477 4980 1919 -456 599 7869 3469 -1245
478 5006 1932 -461 600 7891 3482 -1253
479 5032 1944 -466 601 7913 3495 -1261
480 5058 1956 -471 602 7934 3508 -1269
481 5083 1969 -476 603 7956 3521 -1277
482 5109 1981 -481 604 7978 3534 -1285
483 5135 1994 -487 605 8000 3547 -1293
484 5160 2006 -492 606 8021 3560 -1301
485 5186 2018 -497 607 8043 3573 -1309
486 5211 2031 -502 608 8064 3586 -1317
487 5237 2043 -507 609 8086 3599 -1325
488 5262 2055 -513 610 8107 3613 -1333
122
489 5288 2068 -518 611 8129 3626 -1341
490 5313 2080 -523 612 8150 3639 -1349
491 5338 2093 -528 613 8172 3652 -1357
492 5364 2105 -534 614 8193 3665 -1366
493 5389 2117 -539 615 8215 3678 -1374
494 5414 2130 -545 616 8236 3692 -1382
495 5439 2142 -550 617 8258 3705 -1390
496 5464 2155 -555 618 8279 3718 -1398
497 5489 2167 -561 619 8300 3731 -1407
498 5514 2180 -566 620 8321 3744 -1415
499 5539 2192 -572 621 8343 3757 -1423
500 5564 2205 -578 622 8364 3771 -1432
501 5589 2217 -583 623 8385 3784 -1441
502 5614 2230 -589 62315 8388 3786 -1443
123
Appendix E
Table E1 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in solid state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 913 287 -014
299 025 007 000 331 941 296 -015
300 054 016 000 332 970 306 -016
301 083 025 000 333 998 315 -017
302 112 034 000 334 1026 324 -018
303 141 042 000 335 1054 334 -019
304 170 051 000 336 1081 343 -020
305 199 060 -001 337 1109 353 -021
306 228 069 -001 338 1137 362 -022
307 257 078 -001 339 1165 371 -024
308 286 087 -001 340 1193 381 -025
309 315 096 -002 341 1221 390 -026
310 343 105 -002 342 1248 400 -027
311 372 113 -002 343 1276 409 -028
312 401 122 -003 344 1304 419 -030
313 430 131 -003 345 1331 428 -031
314 458 140 -003 346 1359 438 -032
315 487 149 -004 347 1386 447 -034
316 516 159 -004 348 1414 457 -035
317 544 168 -005 349 1441 466 -036
318 573 177 -006 350 1468 476 -038
319 602 186 -006 351 1496 486 -039
320 630 195 -007 352 1523 495 -041
321 659 204 -007 353 1550 505 -042
322 687 213 -008 354 1577 514 -044
323 715 222 -009 355 1605 524 -046
324 744 232 -009 356 1632 534 -047
325 772 241 -010 357 1659 543 -049
326 800 250 -011 358 1686 553 -050
327 829 259 -012 359 1713 563 -052
328 857 269 -013 35915 1717 564 -052
329 885 278 -013
124
Table E2 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in liquid state (376-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2323 777 -094 500 5525 2173 -590
376 2347 786 -096 501 5548 2184 -595
377 2375 797 -098 502 5572 2196 -601
378 2403 808 -101 503 5595 2208 -606
379 2431 818 -103 504 5619 2220 -612
380 2459 829 -106 505 5642 2232 -618
381 2487 839 -108 506 5665 2243 -623
382 2515 850 -111 507 5689 2255 -629
383 2542 861 -113 508 5712 2267 -635
384 2570 871 -116 509 5735 2279 -640
385 2598 882 -118 510 5759 2291 -646
386 2626 893 -121 511 5782 2303 -652
387 2653 903 -123 512 5805 2315 -658
388 2681 914 -126 513 5828 2326 -664
389 2708 925 -129 514 5852 2338 -669
390 2736 935 -132 515 5875 2350 -675
391 2763 946 -134 516 5898 2362 -681
392 2791 957 -137 517 5921 2374 -687
393 2818 968 -140 518 5944 2386 -693
394 2845 978 -143 519 5967 2398 -699
395 2873 989 -146 520 5990 2410 -705
396 2900 1000 -148 521 6013 2422 -711
397 2927 1011 -151 522 6036 2434 -717
398 2954 1022 -154 523 6059 2446 -723
399 2981 1032 -157 524 6082 2458 -729
400 3008 1043 -160 525 6105 2470 -735
401 3035 1054 -163 526 6128 2482 -741
402 3062 1065 -166 527 6151 2494 -747
403 3089 1076 -169 528 6173 2506 -754
404 3116 1086 -172 529 6196 2518 -760
405 3143 1097 -176 530 6219 2530 -766
125
406 3170 1108 -179 531 6242 2542 -772
407 3197 1119 -182 532 6265 2554 -778
408 3223 1130 -185 533 6287 2566 -785
409 3250 1141 -188 534 6310 2578 -791
410 3277 1152 -192 535 6333 2591 -797
411 3303 1163 -195 536 6355 2603 -804
412 3330 1174 -198 537 6378 2615 -810
413 3356 1185 -202 538 6400 2627 -816
414 3383 1195 -205 539 6423 2639 -823
415 3409 1206 -208 540 6445 2651 -829
416 3436 1217 -212 541 6468 2663 -836
417 3462 1228 -215 542 6490 2676 -842
418 3488 1239 -219 543 6513 2688 -849
419 3515 1250 -222 544 6535 2700 -855
420 3541 1261 -226 545 6558 2712 -862
421 3567 1272 -229 546 6580 2724 -868
422 3593 1283 -233 547 6602 2737 -875
423 3619 1294 -236 548 6625 2749 -882
424 3645 1305 -240 549 6647 2761 -888
425 3671 1317 -244 550 6669 2773 -895
426 3697 1328 -247 551 6692 2786 -902
427 3723 1339 -251 552 6714 2798 -908
428 3749 1350 -255 553 6736 2810 -915
429 3775 1361 -259 554 6758 2822 -922
430 3801 1372 -262 555 6780 2835 -929
431 3827 1383 -266 556 6803 2847 -935
432 3852 1394 -270 557 6825 2859 -942
433 3878 1405 -274 558 6847 2872 -949
434 3904 1416 -278 559 6869 2884 -956
435 3929 1428 -282 560 6891 2896 -963
436 3955 1439 -286 561 6913 2909 -970
437 3981 1450 -290 562 6935 2921 -977
438 4006 1461 -294 563 6957 2933 -983
439 4032 1472 -298 564 6979 2946 -990
440 4057 1483 -302 565 7001 2958 -997
441 4083 1495 -306 566 7023 2971 -1004
442 4108 1506 -310 567 7045 2983 -1011
443 4133 1517 -314 568 7067 2995 -1019
444 4159 1528 -318 569 7089 3008 -1026
445 4184 1540 -322 570 7110 3020 -1033
126
446 4209 1551 -327 571 7132 3033 -1040
447 4234 1562 -331 572 7154 3045 -1047
448 4260 1573 -335 573 7176 3058 -1054
449 4285 1585 -339 574 7198 3070 -1061
450 4310 1596 -344 575 7219 3083 -1069
451 4335 1607 -348 576 7241 3095 -1076
452 4360 1618 -352 577 7263 3108 -1083
453 4385 1630 -357 578 7284 3120 -1090
454 4410 1641 -361 579 7306 3133 -1098
455 4435 1652 -365 580 7328 3145 -1105
456 4460 1664 -370 581 7349 3158 -1112
457 4485 1675 -374 582 7371 3170 -1120
458 4510 1687 -379 583 7393 3183 -1127
459 4534 1698 -383 584 7414 3195 -1134
460 4559 1709 -388 585 7436 3208 -1142
461 4584 1721 -393 586 7457 3221 -1149
462 4609 1732 -397 587 7479 3233 -1157
463 4633 1743 -402 588 7500 3246 -1164
464 4658 1755 -406 589 7522 3258 -1172
465 4683 1766 -411 590 7543 3271 -1179
466 4707 1778 -416 591 7564 3284 -1187
467 4732 1789 -420 592 7586 3296 -1194
468 4756 1801 -425 593 7607 3309 -1202
469 4781 1812 -430 594 7628 3322 -1210
470 4805 1824 -435 595 7650 3334 -1217
471 4830 1835 -440 596 7671 3347 -1225
472 4854 1847 -444 597 7692 3360 -1233
473 4878 1858 -449 598 7714 3373 -1240
474 4903 1870 -454 599 7735 3385 -1248
475 4927 1881 -459 600 7756 3398 -1256
476 4951 1893 -464 601 7777 3411 -1264
477 4975 1904 -469 602 7799 3423 -1271
478 5000 1916 -474 603 7820 3436 -1279
479 5024 1927 -479 604 7841 3449 -1287
480 5048 1939 -484 605 7862 3462 -1295
481 5072 1951 -489 606 7883 3475 -1303
482 5096 1962 -494 607 7904 3487 -1311
483 5120 1974 -499 608 7925 3500 -1318
484 5144 1985 -504 609 7946 3513 -1326
485 5168 1997 -510 610 7967 3526 -1334
127
486 5192 2009 -515 611 7988 3539 -1342
487 5216 2020 -520 612 8009 3551 -1350
488 5240 2032 -525 613 8030 3564 -1358
489 5264 2044 -530 614 8051 3577 -1366
490 5288 2055 -536 615 8072 3590 -1374
491 5312 2067 -541 616 8093 3603 -1383
492 5335 2079 -546 617 8114 3616 -1391
493 5359 2090 -552 618 8135 3629 -1399
494 5383 2102 -557 619 8156 3642 -1407
495 5407 2114 -562 620 8177 3655 -1415
496 5430 2126 -568 621 8198 3667 -1423
497 5454 2137 -573 622 8219 3680 -1431
498 5478 2149 -579 623 8239 3693 -1440
499 5501 2161 -584 62315 8242 3695 -1441
128
Appendix F
Table F1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in solid
state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 1063 334 -017
299 029 009 000 331 1096 345 -018
300 063 019 000 332 1128 356 -019
301 097 029 000 333 1161 366 -020
302 131 039 000 334 1193 377 -021
303 165 050 000 335 1225 388 -022
304 199 060 -001 336 1258 399 -024
305 233 070 -001 337 1290 410 -025
306 267 081 -001 338 1322 421 -026
307 300 091 -001 339 1355 432 -028
308 334 101 -002 340 1387 443 -029
309 368 112 -002 341 1419 454 -030
310 401 122 -002 342 1451 464 -032
311 435 133 -003 343 1483 475 -033
312 468 143 -003 344 1515 486 -035
313 502 153 -004 345 1547 497 -036
314 535 164 -004 346 1578 508 -038
315 569 174 -005 347 1610 519 -039
316 602 185 -005 348 1642 531 -041
317 635 196 -006 349 1674 542 -043
318 668 206 -006 350 1705 553 -044
319 702 217 -007 351 1737 564 -046
320 735 227 -008 352 1769 575 -048
321 768 238 -009 353 1800 586 -049
322 801 248 -009 354 1832 597 -051
323 834 259 -010 355 1863 608 -053
324 867 270 -011 356 1894 619 -055
325 900 280 -012 357 1926 631 -057
326 932 291 -013 358 1957 642 -059
327 965 302 -014 359 1988 653 -061
328 998 313 -015 35915 1993 655 -061
329 1030 323 -016
129
Table F2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in liquid
state (37515-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2691 926 -083 500 6111 2416 -640
376 2717 936 -085 501 6136 2428 -646
377 2747 948 -088 502 6161 2440 -652
378 2778 959 -091 503 6185 2453 -658
379 2808 971 -094 504 6210 2465 -665
380 2838 982 -096 505 6235 2478 -671
381 2869 994 -099 506 6259 2490 -677
382 2899 1005 -102 507 6284 2502 -683
383 2929 1017 -105 508 6308 2515 -690
384 2959 1028 -108 509 6333 2527 -696
385 2989 1040 -111 510 6357 2540 -702
386 3019 1051 -114 511 6381 2552 -709
387 3049 1063 -117 512 6406 2565 -715
388 3079 1075 -120 513 6430 2577 -721
389 3109 1086 -123 514 6454 2590 -728
390 3138 1098 -126 515 6479 2602 -734
391 3168 1109 -129 516 6503 2615 -741
392 3198 1121 -133 517 6527 2627 -747
393 3227 1132 -136 518 6551 2640 -754
394 3257 1144 -139 519 6575 2652 -760
395 3286 1156 -142 520 6599 2665 -767
396 3316 1167 -146 521 6624 2677 -774
397 3345 1179 -149 522 6648 2690 -780
398 3374 1191 -152 523 6672 2702 -787
399 3403 1202 -156 524 6696 2715 -794
400 3433 1214 -159 525 6719 2727 -800
401 3462 1226 -163 526 6743 2740 -807
402 3491 1237 -166 527 6767 2753 -814
403 3520 1249 -170 528 6791 2765 -821
404 3549 1261 -173 529 6815 2778 -827
405 3578 1272 -177 530 6839 2790 -834
130
406 3606 1284 -180 531 6862 2803 -841
407 3635 1296 -184 532 6886 2815 -848
408 3664 1307 -187 533 6910 2828 -855
409 3693 1319 -191 534 6933 2841 -862
410 3721 1331 -195 535 6957 2853 -869
411 3750 1343 -199 536 6981 2866 -876
412 3778 1354 -202 537 7004 2879 -883
413 3807 1366 -206 538 7028 2891 -890
414 3835 1378 -210 539 7051 2904 -897
415 3864 1390 -214 540 7075 2917 -904
416 3892 1401 -218 541 7098 2929 -911
417 3920 1413 -222 542 7122 2942 -918
418 3948 1425 -226 543 7145 2955 -925
419 3977 1437 -230 544 7168 2967 -932
420 4005 1449 -234 545 7192 2980 -939
421 4033 1460 -238 546 7215 2993 -947
422 4061 1472 -242 547 7238 3005 -954
423 4089 1484 -246 548 7261 3018 -961
424 4117 1496 -250 549 7285 3031 -968
425 4145 1508 -254 550 7308 3044 -976
426 4172 1519 -258 551 7331 3056 -983
427 4200 1531 -262 552 7354 3069 -990
428 4228 1543 -266 553 7377 3082 -998
429 4256 1555 -271 554 7400 3095 -1005
430 4283 1567 -275 555 7423 3107 -1013
431 4311 1579 -279 556 7446 3120 -1020
432 4338 1591 -284 557 7469 3133 -1027
433 4366 1603 -288 558 7492 3146 -1035
434 4393 1614 -292 559 7515 3159 -1042
435 4421 1626 -297 560 7538 3171 -1050
436 4448 1638 -301 561 7561 3184 -1058
437 4475 1650 -306 562 7584 3197 -1065
438 4503 1662 -310 563 7607 3210 -1073
439 4530 1674 -315 564 7629 3223 -1080
440 4557 1686 -319 565 7652 3235 -1088
441 4584 1698 -324 566 7675 3248 -1096
442 4611 1710 -328 567 7697 3261 -1103
443 4638 1722 -333 568 7720 3274 -1111
444 4665 1734 -338 569 7743 3287 -1119
445 4692 1746 -342 570 7765 3300 -1126
131
446 4719 1758 -347 571 7788 3313 -1134
447 4746 1770 -352 572 7811 3326 -1142
448 4773 1782 -356 573 7833 3338 -1150
449 4800 1794 -361 574 7856 3351 -1158
450 4826 1806 -366 575 7878 3364 -1166
451 4853 1818 -371 576 7901 3377 -1173
452 4880 1830 -376 577 7923 3390 -1181
453 4906 1842 -381 578 7945 3403 -1189
454 4933 1854 -386 579 7968 3416 -1197
455 4959 1866 -391 580 7990 3429 -1205
456 4986 1878 -396 581 8012 3442 -1213
457 5012 1890 -401 582 8035 3455 -1221
458 5039 1902 -406 583 8057 3468 -1229
459 5065 1914 -411 584 8079 3481 -1237
460 5091 1926 -416 585 8101 3494 -1245
461 5118 1938 -421 586 8124 3507 -1254
462 5144 1951 -426 587 8146 3520 -1262
463 5170 1963 -431 588 8168 3533 -1270
464 5196 1975 -436 589 8190 3546 -1278
465 5222 1987 -441 590 8212 3559 -1286
466 5248 1999 -447 591 8234 3572 -1294
467 5274 2011 -452 592 8256 3585 -1303
468 5300 2023 -457 593 8278 3598 -1311
469 5326 2035 -463 594 8300 3611 -1319
470 5352 2048 -468 595 8322 3624 -1328
471 5378 2060 -473 596 8344 3637 -1336
472 5404 2072 -479 597 8366 3650 -1344
473 5430 2084 -484 598 8388 3663 -1353
474 5455 2096 -490 599 8410 3676 -1361
475 5481 2108 -495 600 8432 3690 -1369
476 5507 2121 -500 601 8454 3703 -1378
477 5532 2133 -506 602 8475 3716 -1386
478 5558 2145 -512 603 8497 3729 -1395
479 5583 2157 -517 604 8519 3742 -1403
480 5609 2170 -523 605 8541 3755 -1412
481 5634 2182 -528 606 8562 3768 -1420
482 5660 2194 -534 607 8584 3781 -1429
483 5685 2206 -540 608 8606 3795 -1438
484 5710 2219 -545 609 8627 3808 -1446
485 5736 2231 -551 610 8649 3821 -1455
132
486 5761 2243 -557 611 8670 3834 -1464
487 5786 2255 -563 612 8692 3847 -1472
488 5812 2268 -568 613 8713 3860 -1481
489 5837 2280 -574 614 8735 3874 -1490
490 5862 2292 -580 615 8756 3887 -1498
491 5887 2305 -586 616 8778 3900 -1507
492 5912 2317 -592 617 8799 3913 -1516
493 5937 2329 -598 618 8821 3926 -1525
494 5962 2342 -604 619 8842 3940 -1534
495 5987 2354 -610 620 8864 3953 -1542
496 6012 2366 -616 621 8885 3966 -1551
497 6037 2379 -622 622 8906 3979 -1560
498 6062 2391 -628 623 8928 3993 -1569
499 6086 2403 -634 62315 8931 3995 -1570
133
Appendix G
Table G1 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid I state (29815-33715K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 319 578 162 -004
299 024 000 000 320 606 170 -005
300 052 000 000 321 633 179 -005
301 080 007 000 322 660 188 -006
302 108 016 000 323 688 197 -007
303 136 024 000 324 715 205 -007
304 164 032 000 325 742 214 -008
305 192 041 000 326 769 223 -009
306 219 049 000 327 796 232 -009
307 247 058 000 328 823 241 -010
308 275 067 -001 329 851 250 -011
309 303 075 -001 330 878 259 -011
310 330 084 -001 331 905 268 -012
311 358 092 -001 332 932 277 -013
312 386 101 -002 333 959 285 -014
313 413 109 -002 334 985 294 -015
314 441 118 -002 335 1012 303 -016
315 468 127 -003 336 1039 312 -017
316 496 135 -003 337 1066 321 -018
317 523 144 -003 33715 1070 331 -019
318 551 153 -004
Table G2 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid II state (36115-36415K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36115 2433 825 -054
134
362 2454 832 -056
363 2478 841 -059
364 2503 850 -061
36415 2506 851 -062
Table G3 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
liquid state (41115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
41115 3833 1366 -210 518 6604 2649 -772
412 3857 1376 -213 519 6628 2661 -778
413 3885 1387 -217 520 6652 2674 -785
414 3913 1399 -221 521 6675 2686 -792
415 3941 1411 -225 522 6699 2699 -798
416 3969 1422 -229 523 6723 2711 -805
417 3997 1434 -233 524 6747 2723 -812
418 4025 1446 -237 525 6770 2736 -819
419 4053 1457 -241 526 6794 2748 -825
420 4081 1469 -245 527 6818 2761 -832
421 4109 1481 -249 528 6841 2773 -839
422 4137 1493 -253 529 6865 2786 -846
423 4165 1504 -257 530 6888 2798 -853
424 4192 1516 -262 531 6912 2810 -860
425 4220 1528 -266 532 6935 2823 -867
426 4248 1539 -270 533 6959 2835 -873
427 4275 1551 -274 534 6982 2848 -880
428 4303 1563 -279 535 7005 2860 -887
429 4330 1575 -283 536 7029 2873 -894
430 4358 1587 -287 537 7052 2885 -902
431 4385 1598 -292 538 7075 2898 -909
432 4412 1610 -296 539 7098 2910 -916
433 4439 1622 -300 540 7122 2923 -923
434 4467 1634 -305 541 7145 2935 -930
135
435 4494 1646 -309 542 7168 2948 -937
436 4521 1657 -314 543 7191 2960 -944
437 4548 1669 -318 544 7214 2973 -951
438 4575 1681 -323 545 7237 2986 -959
439 4602 1693 -328 546 7260 2998 -966
440 4629 1705 -332 547 7283 3011 -973
441 4656 1716 -337 548 7306 3023 -980
442 4683 1728 -341 549 7329 3036 -988
443 4710 1740 -346 550 7352 3048 -995
444 4736 1752 -351 551 7375 3061 -1003
445 4763 1764 -356 552 7398 3074 -1010
446 4790 1776 -360 553 7420 3086 -1017
447 4816 1788 -365 554 7443 3099 -1025
448 4843 1800 -370 555 7466 3111 -1032
449 4869 1812 -375 556 7489 3124 -1040
450 4896 1823 -380 557 7511 3137 -1047
451 4922 1835 -385 558 7534 3149 -1055
452 4949 1847 -390 559 7557 3162 -1062
453 4975 1859 -395 560 7579 3175 -1070
454 5002 1871 -400 561 7602 3187 -1077
455 5028 1883 -405 562 7625 3200 -1085
456 5054 1895 -410 563 7647 3213 -1093
457 5080 1907 -415 564 7670 3225 -1100
458 5106 1919 -420 565 7692 3238 -1108
459 5132 1931 -425 566 7714 3251 -1116
460 5159 1943 -430 567 7737 3263 -1123
461 5185 1955 -435 568 7759 3276 -1131
462 5211 1967 -440 569 7782 3289 -1139
463 5236 1979 -446 570 7804 3302 -1147
464 5262 1991 -451 571 7826 3314 -1155
465 5288 2003 -456 572 7849 3327 -1162
466 5314 2015 -461 573 7871 3340 -1170
467 5340 2027 -467 574 7893 3352 -1178
468 5366 2039 -472 575 7915 3365 -1186
469 5391 2051 -478 576 7937 3378 -1194
470 5417 2063 -483 577 7960 3391 -1202
471 5442 2075 -488 578 7982 3404 -1210
472 5468 2087 -494 579 8004 3416 -1218
473 5494 2099 -499 580 8026 3429 -1226
474 5519 2111 -505 581 8048 3442 -1234
136
475 5545 2123 -510 582 8070 3455 -1242
476 5570 2135 -516 583 8092 3468 -1250
477 5595 2147 -521 584 8114 3480 -1258
478 5621 2160 -527 585 8136 3493 -1266
479 5646 2172 -533 586 8158 3506 -1274
480 5671 2184 -538 587 8180 3519 -1283
481 5696 2196 -544 588 8201 3532 -1291
482 5722 2208 -550 589 8223 3545 -1299
483 5747 2220 -555 590 8245 3557 -1307
484 5772 2232 -561 591 8267 3570 -1315
485 5797 2244 -567 592 8289 3583 -1324
486 5822 2257 -573 593 8310 3596 -1332
487 5847 2269 -579 594 8332 3609 -1340
488 5872 2281 -585 595 8354 3622 -1349
489 5897 2293 -590 596 8375 3635 -1357
490 5922 2305 -596 597 8397 3648 -1365
491 5947 2317 -602 598 8419 3660 -1374
492 5971 2330 -608 599 8440 3673 -1382
493 5996 2342 -614 600 8462 3686 -1391
494 6021 2354 -620 601 8483 3699 -1399
495 6046 2366 -626 602 8505 3712 -1408
496 6070 2379 -632 603 8526 3725 -1416
497 6095 2391 -638 604 8548 3738 -1425
498 6119 2403 -645 605 8569 3751 -1433
499 6144 2415 -651 606 8591 3764 -1442
500 6169 2427 -657 607 8612 3777 -1451
501 6193 2440 -663 608 8633 3790 -1459
502 6217 2452 -669 609 8655 3803 -1468
503 6242 2464 -675 610 8676 3816 -1476
504 6266 2477 -682 611 8697 3829 -1485
505 6291 2489 -688 612 8719 3842 -1494
506 6315 2501 -694 613 8740 3855 -1503
507 6339 2513 -701 614 8761 3868 -1511
508 6363 2526 -707 615 8782 3881 -1520
509 6388 2538 -713 616 8803 3894 -1529
510 6412 2550 -720 617 8825 3907 -1538
511 6436 2563 -726 618 8846 3920 -1547
512 6460 2575 -733 619 8867 3933 -1555
513 6484 2587 -739 620 8888 3946 -1564
514 6508 2600 -746 621 8909 3959 -1573
137
515 6532 2612 -752 622 8930 3972 -1582
516 6556 2624 -759 623 8951 3985 -1591
517 6580 2637 -765 62315 8954 3987 -1592
138
Appendix H
Table H1 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid I
state (29815-35415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 768 241 -011
299 023 007 000 328 794 249 -011
300 050 015 000 329 820 258 -012
301 077 023 000 330 846 266 -013
302 104 031 000 331 872 275 -014
303 131 039 000 332 898 284 -015
304 158 048 000 333 924 292 -016
305 185 056 -001 334 950 301 -016
306 212 064 -001 335 976 310 -017
307 239 072 -001 336 1002 318 -018
308 265 081 -001 337 1028 327 -019
309 292 089 -001 338 1053 336 -020
310 319 097 -002 339 1079 344 -021
311 345 105 -002 340 1105 353 -022
312 372 114 -002 341 1130 362 -024
313 399 122 -003 342 1156 371 -025
314 425 130 -003 343 1182 379 -026
315 452 139 -004 344 1207 388 -027
316 478 147 -004 345 1233 397 -028
317 505 156 -004 346 1258 406 -029
318 531 164 -005 347 1284 415 -031
319 558 172 -005 348 1309 424 -032
320 584 181 -006 349 1335 433 -033
321 611 189 -007 350 1360 441 -035
322 637 198 -007 351 1385 450 -036
323 663 206 -008 352 1411 459 -037
324 689 215 -008 353 1436 468 -039
325 716 223 -009 354 1461 477 -040
326 742 232 -010 35415 1465 478 -040
139
Table H2 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid 2
state (36215-37315K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36215 2387 777 -046
363 2408 809 -055
364 2432 817 -057
365 2457 826 -060
366 2481 835 -062
367 2506 843 -065
368 2530 852 -067
369 2555 861 -070
370 2579 870 -072
371 2604 879 -075
372 2628 888 -077
373 2653 898 -080
37315 2657 907 -083
Table H3 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in liquid
state (37915-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37915 2966 1025 -100 502 6174 2432 -667
380 2991 1034 -102 503 6198 2444 -674
381 3020 1045 -105 504 6222 2456 -680
382 3048 1056 -108 505 6246 2468 -686
383 3077 1067 -112 506 6270 2480 -692
384 3105 1078 -115 507 6294 2492 -699
385 3134 1089 -118 508 6317 2504 -705
386 3162 1100 -121 509 6341 2516 -711
387 3191 1111 -124 510 6365 2528 -718
140
388 3219 1122 -127 511 6388 2541 -724
389 3247 1133 -130 512 6412 2553 -730
390 3275 1144 -134 513 6436 2565 -737
391 3304 1155 -137 514 6459 2577 -743
392 3332 1166 -140 515 6483 2589 -750
393 3360 1177 -144 516 6506 2601 -756
394 3388 1188 -147 517 6530 2613 -763
395 3416 1199 -150 518 6553 2625 -769
396 3444 1210 -154 519 6577 2638 -776
397 3472 1221 -157 520 6600 2650 -782
398 3500 1232 -161 521 6624 2662 -789
399 3527 1243 -164 522 6647 2674 -796
400 3555 1254 -168 523 6670 2686 -802
401 3583 1265 -171 524 6694 2698 -809
402 3611 1276 -175 525 6717 2711 -816
403 3638 1287 -179 526 6740 2723 -822
404 3666 1299 -182 527 6763 2735 -829
405 3693 1310 -186 528 6786 2747 -836
406 3721 1321 -190 529 6810 2760 -843
407 3748 1332 -193 530 6833 2772 -850
408 3776 1343 -197 531 6856 2784 -856
409 3803 1354 -201 532 6879 2796 -863
410 3830 1366 -205 533 6902 2809 -870
411 3857 1377 -209 534 6925 2821 -877
412 3885 1388 -213 535 6948 2833 -884
413 3912 1399 -216 536 6971 2845 -891
414 3939 1410 -220 537 6994 2858 -898
415 3966 1422 -224 538 7017 2870 -905
416 3993 1433 -228 539 7040 2882 -912
417 4020 1444 -232 540 7063 2895 -919
418 4047 1455 -236 541 7086 2907 -926
419 4074 1467 -240 542 7108 2919 -933
420 4101 1478 -245 543 7131 2932 -940
421 4128 1489 -249 544 7154 2944 -947
422 4154 1500 -253 545 7177 2957 -955
423 4181 1512 -257 546 7199 2969 -962
424 4208 1523 -261 547 7222 2981 -969
425 4234 1534 -265 548 7245 2994 -976
426 4261 1546 -270 549 7267 3006 -984
427 4288 1557 -274 550 7290 3019 -991
141
428 4314 1568 -278 551 7313 3031 -998
429 4341 1580 -282 552 7335 3044 -1005
430 4367 1591 -287 553 7358 3056 -1013
431 4393 1602 -291 554 7380 3068 -1020
432 4420 1614 -296 555 7403 3081 -1028
433 4446 1625 -300 556 7425 3093 -1035
434 4472 1636 -305 557 7448 3106 -1042
435 4499 1648 -309 558 7470 3118 -1050
436 4525 1659 -314 559 7492 3131 -1057
437 4551 1671 -318 560 7515 3143 -1065
438 4577 1682 -323 561 7537 3156 -1072
439 4603 1694 -327 562 7560 3169 -1080
440 4629 1705 -332 563 7582 3181 -1087
441 4655 1716 -336 564 7604 3194 -1095
442 4681 1728 -341 565 7626 3206 -1103
443 4707 1739 -346 566 7649 3219 -1110
444 4733 1751 -351 567 7671 3231 -1118
445 4759 1762 -355 568 7693 3244 -1126
446 4785 1774 -360 569 7715 3257 -1133
447 4810 1785 -365 570 7737 3269 -1141
448 4836 1797 -370 571 7759 3282 -1149
449 4862 1808 -375 572 7782 3294 -1157
450 4888 1820 -379 573 7804 3307 -1164
451 4913 1832 -384 574 7826 3320 -1172
452 4939 1843 -389 575 7848 3332 -1180
453 4964 1855 -394 576 7870 3345 -1188
454 4990 1866 -399 577 7892 3358 -1196
455 5015 1878 -404 578 7914 3370 -1204
456 5041 1889 -409 579 7936 3383 -1212
457 5066 1901 -414 580 7957 3396 -1220
458 5092 1913 -419 581 7979 3408 -1228
459 5117 1924 -424 582 8001 3421 -1236
460 5142 1936 -430 583 8023 3434 -1244
461 5167 1947 -435 584 8045 3447 -1252
462 5193 1959 -440 585 8067 3459 -1260
463 5218 1971 -445 586 8088 3472 -1268
464 5243 1982 -450 587 8110 3485 -1276
465 5268 1994 -456 588 8132 3498 -1284
466 5293 2006 -461 589 8154 3510 -1292
467 5318 2017 -466 590 8175 3523 -1300
142
468 5343 2029 -472 591 8197 3536 -1308
469 5368 2041 -477 592 8219 3549 -1317
470 5393 2053 -482 593 8240 3562 -1325
471 5418 2064 -488 594 8262 3574 -1333
472 5443 2076 -493 595 8283 3587 -1341
473 5468 2088 -499 596 8305 3600 -1350
474 5493 2100 -504 597 8327 3613 -1358
475 5517 2111 -510 598 8348 3626 -1366
476 5542 2123 -515 599 8370 3639 -1375
477 5567 2135 -521 600 8391 3652 -1383
478 5592 2147 -526 601 8413 3664 -1391
479 5616 2158 -532 602 8434 3677 -1400
480 5641 2170 -537 603 8455 3690 -1408
481 5665 2182 -543 604 8477 3703 -1417
482 5690 2194 -549 605 8498 3716 -1425
483 5715 2206 -554 606 8520 3729 -1434
484 5739 2218 -560 607 8541 3742 -1442
485 5763 2229 -566 608 8562 3755 -1451
486 5788 2241 -572 609 8583 3768 -1459
487 5812 2253 -578 610 8605 3781 -1468
488 5837 2265 -583 611 8626 3794 -1477
489 5861 2277 -589 612 8647 3807 -1485
490 5885 2289 -595 613 8668 3820 -1494
491 5910 2301 -601 614 8690 3833 -1503
492 5934 2313 -607 615 8711 3846 -1511
493 5958 2324 -613 616 8732 3859 -1520
494 5982 2336 -619 617 8753 3872 -1529
495 6006 2348 -625 618 8774 3885 -1538
496 6030 2360 -631 619 8795 3898 -1546
497 6055 2372 -637 620 8816 3911 -1555
498 6079 2384 -643 621 8837 3924 -1564
499 6103 2396 -649 622 8858 3937 -1573
500 6127 2408 -655 623 8879 3950 -1582
501 6151 2420 -661 62315 8883 3952 -1583
143
Appendix I
Table I1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in solid state (29815-35315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 1171 366 -017
299 035 010 000 328 1211 379 -018
300 076 023 000 329 1250 392 -019
301 117 035 000 330 1290 405 -021
302 158 048 000 331 1330 418 -022
303 199 060 000 332 1369 431 -023
304 240 072 -001 333 1409 444 -025
305 281 085 -001 334 1448 458 -026
306 322 097 -001 335 1488 471 -028
307 363 110 -002 336 1527 484 -029
308 404 122 -002 337 1566 497 -031
309 445 135 -002 338 1605 510 -032
310 486 148 -003 339 1644 524 -034
311 526 160 -003 340 1683 537 -036
312 567 173 -004 341 1722 550 -037
313 608 186 -005 342 1761 563 -039
314 648 198 -005 343 1800 577 -041
315 689 211 -006 344 1839 590 -043
316 729 224 -007 345 1877 603 -044
317 770 237 -007 346 1916 617 -046
318 810 250 -008 347 1955 630 -048
319 850 262 -009 348 1993 643 -050
320 891 275 -010 349 2031 657 -052
321 931 288 -011 350 2070 670 -054
322 971 301 -012 351 2108 683 -056
323 1011 314 -013 352 2146 697 -059
324 1051 327 -014 353 2184 710 -061
325 1091 340 -015 35315 2190 712 -061
326 1131 353 -016
144
Table I2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in liquid state (39115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
39115 4413 1056 -191 508 8890 3521 -978
392 4450 1535 -195 509 8924 3538 -986
393 4492 1549 -200 510 8959 3556 -995
394 4535 1566 -204 511 8993 3574 -1004
395 4577 1583 -209 512 9027 3591 -1013
396 4620 1599 -213 513 9062 3609 -1022
397 4662 1616 -218 514 9096 3626 -1031
398 4704 1633 -223 515 9130 3644 -1041
399 4746 1650 -227 516 9164 3661 -1050
400 4789 1666 -232 517 9198 3679 -1059
401 4831 1683 -237 518 9232 3697 -1068
402 4872 1700 -242 519 9266 3714 -1077
403 4914 1717 -247 520 9300 3732 -1087
404 4956 1734 -252 521 9334 3750 -1096
405 4997 1751 -257 522 9368 3767 -1105
406 5039 1767 -262 523 9402 3785 -1115
407 5080 1784 -267 524 9435 3802 -1124
408 5122 1801 -272 525 9469 3820 -1134
409 5163 1818 -277 526 9503 3838 -1143
410 5204 1835 -282 527 9536 3855 -1152
411 5245 1852 -287 528 9570 3873 -1162
412 5286 1869 -293 529 9603 3891 -1172
413 5327 1885 -298 530 9637 3908 -1181
414 5368 1902 -303 531 9670 3926 -1191
415 5409 1919 -309 532 9703 3944 -1201
416 5450 1936 -314 533 9737 3962 -1210
417 5490 1953 -320 534 9770 3979 -1220
418 5531 1970 -325 535 9803 3997 -1230
419 5571 1987 -331 536 9836 4015 -1240
420 5612 2004 -336 537 9869 4032 -1249
421 5652 2021 -342 538 9902 4050 -1259
145
422 5692 2038 -347 539 9935 4068 -1269
423 5732 2055 -353 540 9968 4086 -1279
424 5772 2072 -359 541 10001 4104 -1289
425 5812 2089 -365 542 10034 4121 -1299
426 5852 2106 -371 543 10066 4139 -1309
427 5892 2123 -376 544 10099 4157 -1319
428 5932 2140 -382 545 10132 4175 -1329
429 5971 2157 -388 546 10165 4192 -1340
430 6011 2174 -394 547 10197 4210 -1350
431 6051 2191 -400 548 10230 4228 -1360
432 6090 2208 -406 549 10262 4246 -1370
433 6129 2225 -412 550 10295 4264 -1380
434 6169 2242 -419 551 10327 4282 -1391
435 6208 2259 -425 552 10359 4299 -1401
436 6247 2276 -431 553 10392 4317 -1411
437 6286 2293 -437 554 10424 4335 -1422
438 6325 2310 -444 555 10456 4353 -1432
439 6364 2327 -450 556 10488 4371 -1443
440 6403 2344 -456 557 10520 4389 -1453
441 6442 2361 -463 558 10553 4407 -1464
442 6480 2378 -469 559 10585 4424 -1474
443 6519 2395 -476 560 10617 4442 -1485
444 6557 2412 -482 561 10648 4460 -1496
445 6596 2429 -489 562 10680 4478 -1506
446 6634 2446 -495 563 10712 4496 -1517
447 6673 2464 -502 564 10744 4514 -1528
448 6711 2481 -509 565 10776 4532 -1538
449 6749 2498 -515 566 10808 4550 -1549
450 6787 2515 -522 567 10839 4568 -1560
451 6825 2532 -529 568 10871 4586 -1571
452 6863 2549 -536 569 10902 4604 -1582
453 6901 2566 -543 570 10934 4622 -1593
454 6939 2584 -550 571 10965 4640 -1604
455 6977 2601 -557 572 10997 4658 -1615
456 7015 2618 -564 573 11028 4676 -1626
457 7052 2635 -571 574 11060 4694 -1637
458 7090 2652 -578 575 11091 4712 -1648
459 7128 2670 -585 576 11122 4730 -1659
460 7165 2687 -592 577 11154 4748 -1670
461 7202 2704 -599 578 11185 4766 -1681
146
462 7240 2721 -606 579 11216 4784 -1692
463 7277 2738 -614 580 11247 4802 -1704
464 7314 2756 -621 581 11278 4820 -1715
465 7351 2773 -628 582 11309 4838 -1726
466 7388 2790 -636 583 11340 4856 -1737
467 7425 2807 -643 584 11371 4874 -1749
468 7462 2825 -650 585 11402 4892 -1760
469 7499 2842 -658 586 11433 4910 -1772
470 7536 2859 -665 587 11464 4928 -1783
471 7573 2877 -673 588 11495 4946 -1794
472 7609 2894 -680 589 11525 4964 -1806
473 7646 2911 -688 590 11556 4982 -1817
474 7682 2928 -696 591 11587 5001 -1829
475 7719 2946 -703 592 11617 5019 -1841
476 7755 2963 -711 593 11648 5037 -1852
477 7792 2980 -719 594 11678 5055 -1864
478 7828 2998 -727 595 11709 5073 -1876
479 7864 3015 -735 596 11739 5091 -1887
480 7900 3032 -742 597 11770 5109 -1899
481 7937 3050 -750 598 11800 5128 -1911
482 7973 3067 -758 599 11831 5146 -1923
483 8009 3084 -766 600 11861 5164 -1935
484 8045 3102 -774 601 11891 5182 -1946
485 8080 3119 -782 602 11921 5200 -1958
486 8116 3137 -791 603 11952 5218 -1970
487 8152 3154 -799 604 11982 5237 -1982
488 8188 3171 -807 605 12012 5255 -1994
489 8223 3189 -815 606 12042 5273 -2006
490 8259 3206 -823 607 12072 5291 -2018
491 8294 3224 -832 608 12102 5309 -2030
492 8330 3241 -840 609 12132 5328 -2042
493 8365 3259 -848 610 12162 5346 -2055
494 8401 3276 -857 611 12192 5364 -2067
495 8436 3293 -865 612 12222 5382 -2079
496 8471 3311 -873 613 12252 5401 -2091
497 8506 3328 -882 614 12281 5419 -2103
498 8542 3346 -890 615 12311 5437 -2116
499 8577 3363 -899 616 12341 5456 -2128
500 8612 3381 -908 617 12370 5474 -2140
501 8647 3398 -916 618 12400 5492 -2153
147
502 8681 3416 -925 619 12430 5510 -2165
503 8716 3433 -934 620 12459 5529 -2178
504 8751 3451 -942 621 12489 5547 -2190
505 8786 3468 -951 622 12518 5565 -2203
506 8820 3486 -960 623 12548 5584 -2215
507 8855 3503 -969 62315 12552 5602 -2217
ii
ABSTRACT
New alkali nitrate-nitrite systems were developed by using thermodynamic modeling and
the eutectic points were predicted based on the change of Gibbs energy of fusion Those systems
with melting point lower than 130oC were selected for further analysis The new compounds
were synthesized and the melting point and heat capacity were determined using Differential
Scanning Calorimetry (DSC) The experimentally determined melting points agree well with the
predicted results of modeling It was found that the lithium nitrate amount and heating rate have
significant effects on the melting point value and the endothermic peaks Heat capacity data as a
function of temperature are fit to polynomial equation and thermodynamic properties like
enthalpies entropies and Gibbs energies of the systems as function of temperature are
subsequently induced The densities for the selected systems were experimentally determined
and found in a very close range due to the similar composition In liquid state the density values
decrease linearly as temperature increases with small slope Moreover addition of lithium nitrate
generally decreases the density On the basis of density heat capacity and the melting point
thermal energy storage was calculated Among all the new molten salt systems LiNO3-NaNO3-
KNO3-Mg(NO3)2-MgKN quinary system presents the largest thermal energy storage density as
well as the gravimetric density values Compared to the KNO3-NaNO3 binary solar salt all the
new molten salts present larger thermal energy storage as well as the gravimetric storage density
values which indicate the better thermal energy storage capacity for solar power generation
systems
iii
DEDICATION
This thesis is dedicated to everyone who helped me and guided me through the trials and
tribulations of creating this manuscript In particular my family and close friends who stood by
me throughout the time taken to complete this masterpiece
iv
ACKNOWLEDGEMENTS
I am pleased to express my gratitude and appreciation to my advisor Professor Ramana
G Reddy for his patience and guidance during my graduate study and the entire research work I
am greatly benefited from his experience knowledge and enthusiasm for scientific research
I would like to express my sincere thanks to Dr Nitin Chopra and Dr Yang-Ki Hong for
serving on my committee Their valuable suggestions and comments are very insightful for my
research work
I would like to thank all the research colleagues of Dr Reddy‟s research group special
thanks to Dr Divakar Mantha for his valuable suggestions and comments I would like to extend
my gratitude to US Department of Energy for the financial support
Finally I would like to thank my parents and my fianceacutee whose invaluable
understanding and loving support helped me through the difficult times
v
TABLE OF CONTENTS
ABSTRACT ii
DEDICATION iii
ACKNOWLEDGEMENTS iv
LIST OF TABLES viii
LIST OF FIGURES x
CHAPTER 1 INTRODUCTION 1
CHAPTER 2 LITERATURE REVIEW 11
21 Melting point 11
22 Density 15
23 Heat capacity 18
CHAPTER 3 OBJECTIVES 22
CHAPTER 4 THERMODYNAMIC MODELING OF SALT SYSTEMS 24
41 Thermodynamic modeling 24
42 Calculations 27
vi
CHAPTER 5 EXPERIMENTAL PROCEDURE 30
51 Melting point determination of molten salt mixtures 30
511 Materials 30
512 Apparatus and Procedure 30
52 Heat Capacity determination of molten salt mixtures 32
53 Density determination of molten salt mixtures 33
CHAPTER 6 RESULT AND DISCUSSION 34
61 Melting point determination 34
611 DSC equipment calibration 34
612 Results 35
613 Discussion 41
62 Heat capacity determination 51
621 Heat capacity calibration 51
622 Results 52
623 Thermodynamic properties 55
624 Discussion of Gibbs energy change for molten salts 84
63 Density determination 86
vii
631 Density calibration 86
632 Results and discussions 82
64 Thermal energy storage density of molten salts 90
CHAPTER 7 CONCLUSION 94
REFERENCES 96
APPENDIX 104
APPENDIX A 104
APPENDIX B 109
APPENDIX C 114
APPENDIX D 118
APPENDIX E 123
APPENDIX F 128
APPENDIX G 133
APPENDIX H 138
APPENDIX I 143
viii
LIST OF TABLES
21 Melting point of various nitrate salt systems 12
22 Melting point of various carbonate salt systems 13
23 Melting point of various fluoridechloride salt systems 14
24 Melting point of various hydroixde salt systems 15
25 Density coefficients A and B of nitrate salts 16
26 Density coefficients A and B of carbonate salts 17
27 Density coefficients A and B of chloridefluoride salts 17
28 Density coefficients A and B of molten salt mixture with hydroxide salts 18
29 Heat capacity of alkali nitrate salt at 500oC 19
210 Heat capacity of alkali carbonate salt at 500oC 19
211 Heat capacity of fluoridechloride salt at 500oC 20
212 Heat capacity of hydroxide salt at 500oC 21
41 Calculated composition and melting point for multi-component systems 29
61 Calibration data of melting points with different samples 35
62 DSC results of melting point transition point and change of enthalpy 41
ix
63 Fusion and solid phase transition temperature for individual salts 42
64 Melting points of candidate systems as function of temperatures 51
65 Calibration data of heat capacities with different samples 52
66 Heat capacity of selected new TES molten salt mixtures 54
67 Change of Gibbs energy values at 62315K for molten salt systems 85
68 Calibration of density measurements with different pure nitrate salts 86
69 Coefficient of A and B for density determination of salt 1 to salt 9 87
610 Extrapolated value of density and heat capacity at 500oC of salt 1 to salt 9 91
611 Energy density of salt 1 to salt 9 compare to solar salt 92
612 Gravimetric storage densities for solar salt and new molten salts 93
x
LIST OF FIGURES
11 Theoretical and engineering energy conversion efficiency as function of temperature 6
12 Gravimetric storage density for different energy storage systems
as function of temperature 8
51 Photography of set-up for DSC equipment 31
61 Melting point calibration with indium sample 34
62 Melting point calibration with KNO3 sample 35
63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt 36
64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt 37
65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt 37
66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt 38
67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt 38
68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt 39
69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt 39
610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt 40
611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN Salt 40
612 DSC plot of 698wt KNO3 -302wt NaNO2 binary system 43
xi
613 DSC plot of 270wt NaNO3-730wt KNO3 binary system 45
614 DSC plot of 458wtLiNO3-542wtKNO3 binary system 45
615 DSC plot of 460wt NaNO3-540wt KNO3 binary system 46
616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 20oCmin heating rate 47
616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 5oCmin heating rate 48
617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 5oCmin heating rate 49
617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 20oCmin heating rate 49
618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system
as function of temperature 53
619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K 54
620 Change of Gibbs energy as function of temperature for molten salt systems 85
621 The densities of the salt 1 to salt 5 as function of temperature 87
622 The densities of the salt 6 to salt 9 as function of temperature 89
623 Densities of the salt 1 salt 2 as function of temperature compared to
the equimolar NaNO3-KNO3 binary system and pure KNO3 90
624 Gravimetric storage density comparison of different energy storage
xii
systems as function of temperature 93
1
CHAPTER 1
INTRODUCTION
Renewable energy sources such as wind solar water power geothermal and biomass are
playing more and more significant role in our energy supply Because the cheap cost and infinite
amount of energy storage inside the resource solar energy is emphasized since 20th
century and
viewed as promising alternative method to satisfy the large energy consumption every day in the
world reduce the emission of carbon and strengthen the economy
The wind energy was used as a clean energy to generate electricity back to late 19th
century
However this renewable energy source was not emphasized due to the cheap price of fossil fuel
The re-emergence happened in mid 1950s when the amount of traditional energy source was
found apparently decrease The development of wind energy usage continued and in 1990 the
first mega-watt wind turbine was launched which was viewed as a symbol of shift to large scale
wind energy utilization [1-2] The modern application of wind energy mainly relies on wind
turbine On the basis of aerodynamic wind turbine generates certain net positive torque on
rotating shaft and then converts the mechanical power to electrical power As an electrical power
generator wind turbine is connected to some electrical network to transport the electricity to
battery charging utilities residential power systems and large scale energy consuming systems
In general most of wind turbines are small scale and can only generate 10KW electrical power
Only few of the wind turbine systems operate with capacity as large as 5MW Although the
usage of wind energy can reduce the emission of carbon oxide the noise pollution and high cost
2
limit its large scale application Since the wind is not transportable the electrical energy can only
be generated where the wind blows which also decrease the flexibility of wind energy
Water power is another term of alternative power supply and it was used for irrigation
operating machines like watermill even before the development of electrical power The modern
application of water power is to generate electricity by using the gravitational force of falling or
flowing water These days there are various ways for the water power application The most
traditional method is to store the water in dam and generate electricity by converting the
potential energy pump storage is a different way to utilize water power and can change its
output depending on the energy demand by moving water between reservoirs at different
elevations In the low energy demand period excess energy is used to lift water to the higher
level while in the peak period of energy demand the water is released back to the lower
elevation through water turbine Water power can also be converted by taking advantage of
naturally raise and fall of tide to satisfy the demand of electrical energy consumption [3]
Although the usage of water power can reduce the emission of carbon dioxide and cost it will
destroy the ecosystem because of the large land required for construction There will be methane
emission from the reservoir the potential failure hazard of dam is also a fatal issue and flow
shortage caused by drought may also create serious problem As result of that water power
technique is not a long-term alternative choice
Geothermal energy is the energy form generated inside the earth At the very beginning of
the planet formation a large amount of thermal energy was stored from the radioactive decay of
minerals volcanic activity and solar energy absorption Because of the temperature difference
3
between the core and the surface of planet the thermal energy stored inside the earth is driven to
the outer surface in the form of heat This form of renewable energy source can be applied to
generate electrical power and heat for industrial space and agricultural applications
Theoretically the deposited amount of geothermal energy is adequate to supply the energy
consumption in the world However most of the geothermal energy is stored deeply near the
core of the earth the deep drilling and exploration of geothermal energy is very expensive and
limits the large-scale use of this renewable energy source [4]
Biomass is a renewable energy source used to generate heat or electricity with living or
recently living organism such as wood waste (hydrogen) gas and alcohol fuels The biomass
energy can be converted to electrical energy by thermal method such as combustion pyrolysis
and gasification Several specific chemical processes may also be able to convert the biomass
energy to other forms The main problem arise from application of biomass is air pollution which
contains carbon monoxide NOx (nitrogen oxides) VOCs (volatile organic compounds)
particulates and other pollutants And the level of air pollution to some extent is even above that
of traditional fuel resource Some other possible issue like transportation and sink of carbon also
limit the wide usage of this type of alternative energy [5]
Among all the renewable energy sources solar energy is the most suitable alternative
energy for our future life It is clean cheap abundant without any noise air pollution no
transportation issue and easy to be obtained anywhere in the earth Inside the core of the Sun
hydrogen fuses into helium with a rate of 7times1011
kgs and generates very powerful nucleation
power This type of nucleation explosion creates ultra high temperature in the core of the Sun
4
which reaches approximately 16 million K degrees Although the Sun is not perfectly black body
it still radiates abundant power with the energy density as 16times107 wattsm
2 [6-7] Because of the
enough amount of hydrogen underneath the surface of the Sun the radiation given arise of from
the nucleation explosion can continue at least 5 million years with the same rate and strength
The energy reaching the earth is vastly reduced mainly caused by the absorption and spreading
of the radiation It is easily to understand that there are numerous amorphous objects all around
the entire universe which can absorb certain portion of the radiation for the Sun Moreover the
light generated from the spherical object such as the Sun fills all the available space between the
origin to the destination Even though the energy will not be lost in the travelling process due to
the long distance between the Sun to the earth the surface area of the sphere which is formed
with the Sun as center and the distance as radius is much larger than that of the earth As the
result of that only 1340Wm2 finally reaches the upmost surface of the earth Even though the
final amount of the received solar energy is very small compared to that is initially radiated from
the Sun the average daily solar radiation falling on one area in the continental United States is
equivalent in total energy content to 11 barrels of oil In summary the solar energy itself is
relatively unlimited useful clean and almost unexploited energy and definitely can behave as
the promising mean for the future energy supply [8]
There are several different methods to take advantage of the solar energy and all the
methods can be distinguished into three group solar parabolic trough solar tower and solar dish
Parabolic trough is constructed by silver coated parabolic mirror and there is a Dewar tube going
through the length of the mirror and set on the focal point all the radiation is concentrated on the
tube and transfer by heat transfer fluid to the thermal energy storage unit Solar tower are used to
5
capture solar energy with thousands of mirrors and focus the concentrated sunlight to the top of
the tower which is located in the middle of the heliostats The thermal energy storage medium
within the tower was heated to high temperature and transferred to thermal energy storage tank
and eventually sent to steam pump The solar dish is built with a large reflective parabolic dish
which concentrates all the received sunlight to one spot There is normally a receiver located on
the focal point and transform the solar energy to other forms of useful energy The working
upper limit temperature of solar parabolic trough system is the lowest among these three systems
normally its maximum working temperature is within the range from 400-500oC the solar tower
has higher maximum working temperature which ranges from 500-1000oC the solar dish has the
highest working upper limit temperature which reaches 700-1200oC [9]
The energy conversion efficiency is the most concerned parameter in the solar energy
storage application and the theoretical and real engineering efficiency are given in fig 11 as
function of temperature The theoretical conversion efficiency can be up to 80 while in real
application the value is always less than 70 regardless of collectors The actual efficiency
increases with temperature in the whole working temperature As a result of that the thermal
energy storage materials in solar parabolic trough for instance should be able to work stably at
the upper limit temperature of this type of collection system which is 500oC to ensure the highest
efficiency [9 10]
6
Fig 11 Theoretical and engineering energy conversion efficiency as function of
temperature
Solar energy can be stored in three major forms sensible heat latent heat and
thermochemical heat Sensible heat storage was utilized based on the heat capacity and the
change as function of temperature of storage materials in the charging and discharging process
which correspond to the absorbing and withdrawing energy processes respectively The sensible
heat stored from the melting point to the maximum working temperature can be expressed by
equation 1 [9]
[1]
Where m is the mass of storage material Tmp and TH are melting point temperature and high
temperature in the same phase respectively Cp(T) is the heat capacity at different temperature
Because the sensible heat storage materials remain in a single phase in the working temperature
range the charging and discharging processes are completely reversible for unlimited cycles
7
Latent heat storage is operated by absorbing and withdrawing energy in the charging and
discharging processes accompanied with fusion of materials [9] The latent heat collected
throughout the working temperature range can be expressed by equation 2 as following
[2]
Where T is temperature in solid state Tmp is melting point temperature of storage material TH is
the high temperature in liquid state and is enthalpy of fusion
Thermochemical heat storage is based on the heat capacity and its change as function of
temperature accompanied with chemical reaction The thermochemical heat collected throughout
the working temperature range can be expressed by equation 3
[3]
Where TL is the low temperature before the reaction TR is the reaction temperature and
is the enthalpy of chemical reaction Because of the destruction of the chemical bonds
in the reaction process the charging and discharging process cannot be completely reversible
which reduces the stability and recyclability of storage operation [10]
Sensible energy storage method is chosen to ensure the efficient usage of solar energy for
parabolic trough system of which the maximum working temperature ranges from 400-500oC
Different from thermochemical heat storage the sensible heat storage can achieve completely
reversible working condition under unlimited cycles Also fig 12 illustrates that the sensible
heat storage materials mainly work in the working temperature range for parabolic trough system
8
and the gravimetric energy storage densities of sensible heat is higher than that of latent heat
materials [9 -11]
Fig 12 Gravimetric storage density for different energy storage systems as function of
temperature
Various materials are chosen to serve as thermal energy storage fluid for sensible heat
such as water thermal oil ionic liquid and molten salt [12] The properties of different heat
transfer fluid determine the performance of solar energy heating system In these days the
efficiency and cost of output of electrical power mainly relies on the parabolic trough solar
power plant and the thermal storage fluid [12] A large investment cost is needed to dispatch
100MW to 200MW energy by consuming the energy transfer fluids Given by this situation the
development of new thermal storage fluid with higher thermal energy storage density is
paramount to lower the expense for generating energy and a lot of effect has been put on design
of new systems [13-16]
9
Water is commonly used as heat transfer and thermal energy storage fluid in industry
because of its low cost high heat capacity and high thermal conductivity However the
limitation for using this medium is also obvious that the temperature range within which the
liquid state can be assured is too small It is well know that water can only serve as thermal
energy storage liquid above the freezing point 0oC and below the boiling temperature 100
oC In
practical experiment the actual temperature range is even less than 100oC because of the large
amount of weight loss near the boiling temperature due to the high vapor pressure Water is
possible to work above 100oC only if high pressure is also applied to avoid the phase
transformation but the cost will be highly increased Accordingly water is only suitable to work
in low temperature below 100oC
Thermal oils are also being used in the parabolic trough solar power plant and have very
low melting point as low as 12oC [17 18] However the application of the oil for the thermal
energy storage liquid is limited by some disadvantages from the physic-chemical properties The
upper limit for this oil is only 300oC and above that the liquid state cannot be maintained
Moreover the low thermal decomposition temperature low density and low heat capacity result
in limited thermal energy storage capacity Since the working temperature range is so narrow the
rankie cycle efficiency is reduced when using the synthetic oil and the cost for generating power
is considered to be very expensive [19 20]
Ionic liquid is another medium served as thermal energy storage fluid The liquid
temperature range of ionic liquid is large which is one of the main advantages of this type of
material The high heat capacity and density ensure the efficiency of thermal energy storage of
10
ionic liquid What‟s more the excellent chemical stability and little vapor pressure increase the
lifetime [21-24] However as a result of the very serve corrosion problem to the liquid container
and the high cost the usage of ionic liquid is still limited
Considering various relative physic-chemical properties of thermal energy storage system
molten salts have been proposed as a suitable group for a wide temperature range application
They are being emphasized in the solar energy applications because of their low melting point
and high upper limit which can increase the stable working range The high heat capacity
increases the thermal energy storage density of the heat storage system excellent thermal
stability and negligible vapor pressure ensure the steadiness of cyclic repeating in the lifetime
[25] low viscosity strengths the mobility and efficiency of the thermal storage liquid low
utilization cost reduce the investment and protect the economy The liquidus temperature range
of the molten salt varies from 150-600oC combination of various salts can bring the melting
down and further increase the working temperature range Due to these properties molten salts
can be excellent thermal energy storage fluid in the solar power generation system
11
CHAPTER 2
LITERATURE REVIEW
Several physical and thermodynamic properties of thermal energy storage fluid play
significant role in determining the efficiency and performance of solar energy storage systems In
order to evaluate the feasibility of systems the physic-chemical properties of several molten salts
should be reviewed The three determining parameter which directly affect the thermal energy
storage capacity in systems are melting point heat capacity and density
There are large amount of melting point data available in the literature for various molten
salt system in previous literatures while those with melting point less than 120oC is very limited
All the previous study on molten salt system revealed that five group of molten salts are
emphasized and commonly used alkai or alkaline nitrates carbonates sulphates chloride and
hydroxides Although most of the systems have the same group of cation the melting point
varies a lot from one to anther due to the different effect of anions
21 Melting point
The melting points of individual and multi-component nitratenitrite systems are listed in
Table 21[26-31] Among those systems solar salt (NaNO3KNO3 6040) is the thermal energy
storage medium which is currently being used with the freezing point of 221oC [27] Although
the melting point for this system is highest in all the candidate mixtures in this group the lowest
12
combined compound cost makes it widely used in solar energy storage field Another ternary
system HITEC which contains NaNO3 KNO3 and NaNO2 has freezing point of 141 oC [28]
This combination brings the melting point down but the lack of combination of optimum features
limits its further application [29] Some mixtures such as LiNO3-Ca(NO3)2-KNO3 are not often
utilized because they increase the compound cost at the same time of lowering the melting point
to around 120oC [30] moreover the decreased melting point is still high compared to the
organic oil There are also several systems have the melting points less than 100oC or even 60
oC
they are not used in the parabolic trough solar power plant due to the decomposition of some
components during high temperature [31]
Table 21 Melting point of various nitrate salt systems
Compound Melting Point (ordmC)
LiNO3 253
NaNO3 307
KNO3 334
Ca(NO3)2 561
Sr(NO3)2 570
Ba(NO3)2 590
NaNO3-NaNO2 221
NaNO3-NaNO2-KNO3 141
NaNO3-KNO3-CaNO3 133
LiNO3-KNO3-NaNO3 120
KNO3-CaNO3-LiNO3 117
LiNO3-KNO3-NHNO3 92
KNO3-NHNO3-AgNO3 52
The melting points of individual and multi-component carbonate systems are listed in
Table 22 [26 32 33] Different from the nitrate salts the melting points for both the individual
13
and multi-component carbonate systems are on the higher side The lowest melting point is
achieved with lithium sodium and potassium carbonate ternary system whose melting point is
still 277oC higher than that of the nitrate ternary system with the same cations [32] Besides
because of the thermal decomposition issue the choice of component involved in the multi-
component carbonate systems is limited Some salt like CaCO3 doesn‟t have stable form at high
temperature and the lack of multi-component system reduces the chance of the synthesis of low
melting point salt mixtures Even though this group of salt is not thermally stable and the
working temperature range is relatively small it is still viewed as possible candidate working at
high temperature due to its low price
Table 22 Melting point of various carbonate salt systems
Compound Melting Point (ordmC)
Li2CO3 732
Na2CO3 858
K2CO3 900
MgCO3 990
Na2CO3-K2CO3 710
Li2CO3-Na2CO3 496
Li2CO3-K2CO3 488
Li2CO3-K2CO3-Na2CO3 397
Alkali and Alkaline fluoridechloride salts are also selected as one possible choice as the
thermal energy storage fluid and the melting point examined from previous literatures are given
in table 23 [34-38] A lot of study has been done for this group of salt and the melting points
were found in the same range as the carbonate group And for the pure salt metal chloride salts
have lower melting point than metal fluoride ones
14
Table 23 Melting point of various fluoridechloride salt systems
Compound Melting Point (ordmC)
LiF 849
NaF 996
KF 858
LiCl 610
NaCl 801
KCl 771
LiF-KF 493
LiF-NaF 652
LiCl-KF 487
LiF-NaF-KF 454
LiF-NaF-KF-MgF2 449
LiF-KF-BaF2 320
LiF-KF-CsF-RbF 256
Several studies were also conducted to determine the melting point of molten hydroxide
salts and the results are shown in Table24 The data of pure salts and multi-component mixtures
merely in this group were not much determined in the literatures Generally they are mixed with
other groups of anion and form some low melting point salt mixtures [39-42] On the basis of the
previous literature data alkali hydroxide salts and their mixture with salts in other groups have
relatively lower melting point compared with pure carbonate and fluoride chloride group salt
mixtures Most of the melting points given in Table 4 are lower than 300oC sodium potassium
hydroxide binary mixture even reaches the melting point below 200oC Accordingly relatively
large temperature range can be obtained by using hydroxide salt mixtures or adding them as
additive
15
Table 24 Melting point of various hydroixde salt systems
Compound Melting Point (ordmC)
LiOH-LiF 427
NaOH-KOH 170
LiOH-NaOH 213
NaOH-NaNO2 232
NaOH-NaNO3 237
NaOH-NaCl-NaNO3 242
NaOH-NaCl-Na2CO3 282
22 Density
For the solar energy storage system density for the thermal energy storage fluid is also
essential parameter The density is needed for the size calculation as function of temperature and
assessing for the thermal stability of thermoclines Besides density as function of temperature is
used to evaluate the volume change in the process of freezing which contributes to potential
stress
Alkalialkaline nitrate salts were studied very much about their density as function of
temperature All the results indicate that the density was decreased linearly as temperature
increases and any specific density value in the molten state can be expressed by equation as
equation 4
= A-BT [4]
Where (gcm3) is the density of salt A (gcm
3) is the initial density value at 0
oC and B
(mgcm3degC) is the density change slope as function of temperature The coefficients are shown in
16
Table 25 for the nitrate group molten salts Among these systems pure sodium nitrate has the
largest value which reveals the high initial density value at low temperature [43] Conversely
lithium nitrate has the lowest value while it presents the smallest decrease trend as temperature
increases [44] The densities and A B values of multi-component nitrate salts were included in
the range of those two salts discussed above
Table 25 Density coefficients A and B of nitrate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiNO3 1922 0556
NaNO3 2334 0767
KNO3 2127 0760
NaNO3-KNO3 2134 0773
KNO3-CaNO3-LiNO3 2172 0735
LiNO3-KNO3-NaNO3 2083 0715
Several experiments were also conducted to measure the density as function of temperature
for the individual and multi-component carbonate salt systems The density of the carbonate salt
also follow the same trend as that of nitrate salt and the temperature dependence of density
followed the linear equation as discussed above It is observed that all the carbonate salts have
higher initial density coefficient A than the nitrate salt The largest value is reached to 2511 and
even the lowest value in this group is greater than the maximum A of nitrate group [45-49]
What‟s more the regression slope coefficient B of carbonate salt is lower compared to that of the
nitrate salt group Accordingly the salts in this group present larger density in the molten state
and the density coefficient A and B are given in Table 26
17
Table 26 Density coefficients A and B of carbonate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
Li2CO3 2303 0532
Na2CO3 2350 0448
Na2CO3-K2CO3 2473 0483
Li2CO3-K2CO3 2511 0599
Li2CO3-Na2CO3 2456 0519
Li2CO3-Na2CO3-K2CO3 2364 0544
Density of metal fluoride and chloride molten salt were also examined and present similar
regression trend as temperature increases The linear temperature dependence is also expressed
by the same equation On the basis of previous literature data the pure chloride salt shows lower
density than the fluoride salt with the same cation in the molten state [49] What‟s more the
sodium halide salt has the largest density value while the lithium halide salt has the lowest value
which is very similar to the nitrate group salt The density determination coefficient A and B are
given in Table27
Table 27 Density coefficients A and B of chloridefluoride salts
Compound A(gcm3) Btimes103(gcm
3degC)
LiCl 1766 0432
NaCl 1991 0543
KCl 1976 0583
LiF 2226 0490
NaF 2581 0636
KF 2469 0651
LiF-NaF 2520 0818
LiCl-NaF-KCl 2436 0742
LiF-NaF-MgF 2240 0701
18
The density measurement of hydroxide was not conducted as much as those three anion
groups discussed above Only few data of density is available for the alkali hydroxide salt when
added into other salt systems and temperature dependence also follows the linear regression
trend [32 41] The density determination coefficient A and B are given in Table 28
Table 28 Density coefficients A and B of molten salt mixture with hydroxide salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiCl-LiOH 16 0443
LiF-LiOH 165 0471
23 Heat capacity
In the heating process the temperature of solar energy storage molten salt is increase by
absorbing energy from the solar radiation Conversely the same amount of heat is released and
applied to heating system in the process of cooling Heat capacity is the amount of heat required
to increase the temperature of certain material by 1 oC and can be viewed as the directly relevant
parameter to the energy storage ability To some extent the large heat capacity assures the
efficiency of the application of solar energy storage materials
The heat capacity of alkalialkaline nitrate salt was investigated for both individual and
multi-component system in the previous literature To simplify the comparison only the heat
capacity value at 500oC is shown in all the following tables In the liquid state the heat capacity
increases with temperature following linear equation and the increasing slope is as small as 10-5
to 10-4
[50 51] Among those alkali nitrate salt systems lithium nitrate has the largest heat
19
capacity at 500oC while potassium nitrate presents the lowest value at that temperature In table
29 the heat capacity results at the selected temperature in literature are given
Table 29 Heat capacity of alkali nitrate salt at 500oC
Compound Heat capacity(JgK)
LiNO3 2175
NaNO3 1686
KNO3 1400
NaNO3-KNO3 1533
LiNO3-KNO3 1642
LiNO3-KNO3-NaNO3 1681
For the carbonate salt systems in the molten state the heat capacity is almost constant and
almost independent with temperature [32 33] Same as the nitrate group salts the heat capacity
for pure carbonate salt decreases as the atomic number of the alkali element increases which
means the value for lithium carbonate is the largest and that of potassium carbonate is the
smallest Generally the heat capacity value for carbonate in molten state is larger than that in
solid state However the sodium-potassium carbonate binary system is an exception for which
the heat capacity in solid state is larger than liquid state In table 210 the heat capacity results of
carbonate salts at the selected temperature in literature are given
Table 210 Heat capacity of alkali carbonate salt at 500oC
Compound Heat Capacity(JgK)
Li2CO3 250
Na2CO3 178
K2CO3 151
Na2CO3-K2CO3 157
20
Li2CO3-K2CO3 160
Li2CO3-Na2CO3 209
Li2CO3-K2CO3-Na2CO3 163
The heat capacity of fluoridechloride salt was measured in several literature and found
that for the pure salt the lithium halide has the biggest heat capacity data in the molten state
while the potassium halides shows the lowest heat capacity value Similar to the carbonate group
the heat capacity value of fluoridechloride salt varies little with temperature in the liquid state
[32 33] The values at 500oC for the alkalialkaline halides are shown in Table 211
Table 211 Heat capacity of fluoridechloride salt at 500oC
Compound Heat Capacity (JgK)
LiCl 148
NaCl 115
KCl 090
LiF-KF 163
NaCl-MgCl2 100
LiF-NaF-KF 155
KCl-MgCl2-CaCl2 092
The heat capacity of pure and multi-component hydroxide salt systems is limited in the
previous literature and the values in the liquid state follow linear equation which is observed for
all the molten salt discussed above [52] The values at 500oC for the alkalialkaline halides are
shown in Table 212
21
Table 212 Heat capacity of hydroxide salt at 500oC
Compound Heat Capacity(JgK)
NaOH 188
LiOH-NaOH 221
NaOH-KOH 182
In summary on the basis of comparison of various physic-chemical properties molten
nitrate slats have relatively low melting point excellent working temperature range reasonable
density and high heat capacity As the result of that molten nitrate salt is suitable to be applied as
the thermal energy storage fluid in the solar energy storage system
22
CHAPTER 3
OBJECTIVES
Based on review of previous literature data it is found that there are several disadvantages
such as the high melting point relatively low density value or poor heat capacity in liquid state
which limit the application of molten salt in certain groups in solar thermal energy storage
system Conversely alkalialkaline nitrate salt is considered as the suitable choice and proposed
as the thermal energy storage liquid for high temperature
Currently the used thermal energy storage liquid is NaNO3 (60mol)-KNO3 (40mol)
binary system (solar salt) which has the melting point at 221oC [30] Although the melting point
for this salt mixture is not the lowest it is still emphasized because of its low investment cost
However there are some drawbacks for this binary nitrate mixture The main disadvantage is
the high melting point In evenings or in winter the molten salt can easily freeze and block the
pipeline As a result of that some auxiliary cost should be added to overcome this problem and
the total investment will be increased
Development and synthesis of newer molten salt mixtures with freezing point lower than
those currently used for thermal energy storage applications is necessary for higher efficiency of
utilization of solar energy and getting rid of any unnecessary cost The approach to develop
lower freezing point molten salt mixtures is by the prediction of new eutectic mixtures and also
23
by the development of new nitrate compounds Besides these two most well known systems
several other mixtures were also studied Preliminary evaluation of several new molten salt flux
systems based on requirements for thermal energy storage systems mainly including freezing
point density heat capacity viscosity and thermal energy storage density The promising
candidate low melting point molten salt system should satisfy the requirements that eutectic
melting temperatures are lower than 220oC and the thermal energy storage densities are higher
than binary solar salt It is known that the melting point can be lowered by the addition of one or
more ABNO3 nitrate compounds where A and B are cations Consequently several multi-
component systems which have more constituent salts than solar salt were came up with and
studied with little fundamental data on the physic-chemical properties at the required operating
conditions available at present
In this thesis the new systems with simulated eutectic compositions were tested for their
experimental melting points heat capacities using the Differential Scanning Calorimetry (DSC)
technique which is considered to be the accurate instrument for thermodynamic data analysis
[53-59] Some significant thermodynamic properties such as heat capacity enthalpy and entropy
and Gibbs energy were calculated in the thesis to evaluate the energy change of the system in the
phase change process and the potential of being applied in the parabolic trough solar power plant
The energy density was obtained by using the experimental measured density and heat capacity
of the mixtures in molten state Finally 9 down-selected systems were present and discussed
24
CHAPTER 4
THERMODYNAMIC MODELING OF SALT SYSTEMS
41 Thermodynamic modeling
To lower the melting point of solar energy storage system multi-component system is
applicable Thermodynamic model was introduced to predict the eutectic temperature of salt
systems based on the Gibbs energies of fusion of individual salt and that of mixing of constituent
binary systems At the eutectic temperature the Gibbs energies in the liquid state and solid state
of salt are equal In thermodynamics Gibbs energy of fusion can be expressed by the equation
given as follows
G = H-TS [5]
Where H is the change of enthalpy of fusion and S is the change of entropy of fusion Equally
the entropy change of fusion can be expressed by differentiating G and the equation is given
[6]
It is known that the change in entropy can be expressed in terms of change in heat capacity in the
melting process as
[7]
25
If the change of heat capacity is assume to be independent of temperature the integral of
from Tm to T can be shown as
[8]
where Sm is the entropy of fusion at the melting point which is equal to Accordingly
Eq8 can be rewritten as
[9]
Substituting Eq 9 in Eq 6 and integrating the equation from Tm to T we get
[10]
Eq 10 illustrates that by using the change of heat capacity melting point and enthalpy of fusion
the Gibbs energy change at any temperature can be obtained
The standard Gibbs energy of fusion of a salt bdquo1‟ can be expressed in terms of the activity
of the salt as
[11]
where is the molar excess Gibbs energy and X1 is the molefraction of the salt bdquo1‟ Gibbs
energy of fusion at any give temperature T is expressed by Eq 7 in terms of its molefraction and
partial molar excess Gibbs energy
26
Take LiNO3-NaNO3-KNO3 as an example in which the integral molar excess Gibbs energy is
composed of the summation of the Gibbs energies of three constituent binary system and one
ternary The expression of the integral excess Gibbs energy is given by Eq12
[12]
Gibbs energies of the three constituent binary systems LiNO3-NaNO3 LiNO3-KNO3 and
NaNO3-KNO3 of the LiNO3-NaNO3-KNO3 ternary system are taken from the literature [48 49]
The Gibbs energies of mixing or the integral excess Gibbs energies of the three constituent
binary systems of the LiNO3-NaNO3-KNO3 ternary system are given below
LiNO3-NaNO3 Binary System
Jmol [13]
LiNO3-KNO3 Binary System
Jmol [14]
NaNO3-KNO3 Binary System
Jmol [15]
When assume the intergral excess Gibbs energy of to be zero the excess Gibbs energy in
the ternary system can be expressed by the summation of three constituent binary systems
[16]
27
Generally the partial molar excess Gibbs energies are reduced from the integral molar
excess Gibbs energy and can be expressed by the generalized equation for certain ldquomrdquo
component salt as
[17]
In the ternary system the i value equals to 12 and 3 and the partial molar excess Gibbs energy
of mixing for each component can be expressed as follows
[18]
[19]
[20]
Based on Eq 7 and the partial molar excess Gibbs energy of individual component the
Gibbs energy in the fusion can be expressed as Eq21- 23
[21]
[22]
[23]
42 Calculations
The fusion of the ternary salt system is defined by solutions of Eq 21-Eq 23 Newton-
Raphson method can be used to solve these three non-linear equations by linearizing the non-
linear equations using the Taylor series and truncating the series to first order derivatives
28
Consider the three non-linear functions F G and H in three variables x y and z The three
equations that are solved for the three variables are written as
F(x y z) = 0
G(x y z) = 0
H(x y z) = 0 [24]
The partial derivatives of the function F with respect to x y and z are given as
[25]
Similarly the partials derivatives can be expressed for the other two functions G and H
Newton-Raphson iterative method of solving the three equations in three variables
essentially deals with the solution of the incremental vector in the matrix equation given below
[26]
For the initial values of x y and z (say xi yi and zi) the right hand side vector contains the
values of the functions at the initial values (xi yi and zi) The 3times3 matrix on the left hand side
contains the partial derivatives of the functions with respect to the three variables at the initial
values Solutions of the matrix equation (Eq 26) result in the increments of the variables x y
and z The variables for the next iteration will then be xi + x yi + y and zi + z The
process of solving the matrix equation (Eq 26) is continued until the increments in the variables
x y and z is less than a very small quantity The iteration process is then said to be
29
converged and the values of the variables at convergence of the solution are the roots of the
system of the three fusion equations
The composition of LiNO3 NaNO3 and KNO3 and the eutectic temperature is solved by
using the Newton-Raphson iterative method Different from the data in previous literature the
eutectic temperature for the ternary is 116oC Besides the composition for each component is
also different from those published in literatures The new molten ternary system is composed of
2592 wt LiNO3 2001 wt NaNO3 and 5407 wt KNO3 The similar method is also applied
to other multi-component systems to determine the composition and eutectic temperature The
predicted melting points for new solar energy storage system are given Table41
Table 41 Calculated composition and melting point of multi-component molten salts systems
System Composition (wt) Calc Tmp
LiNO3 NaNO3 KNO3 NaNO2 KNO2 Mg(NO3)2 MgKN (degC)
Salt 1 259 20 541 - - - - 116
Salt 2 - 161 547 292 - - - 1238
Salt 3 175 142 505 178 - - - 986
Salt 4 115 104 274 - - - 507 986
Salt 5 172 139 476 172 41 - - 957
Salt 6 9 423 336 - 151 - - 1000
Salt 7 193 - 546 237 24 - - 1081
Salt 8 193 - 559 239 - 09 - 1008
Salt 9 154 172 324 - - 83 267 1036
30
CHAPTER 5
EXPERIMENTAL PROCEDURE
51 Melting point determination of molten salt mixtures
511 Materials
Ternary quaternary and quinary nirate and nitrite mixtures were tested in the thesis Most
components in the mixtures don‟t require any pre-preparation and can be used as received The
only exception is new developed MgKN which was composed of 6667 mol KNO3 and 3333
mol Mg(NO3)2 This unique compound is synthesized from magnesium nitrate hexahydrate
(98 Alfa Aesar) and potassium nitrate (ACS 990 min Alfa Aesar) and added into the
mixture as one single component As received magnesium nitrate hexahydrate is dehydrated
before synthesizing MgKN compound Weighted amount of magnesium nitrate taken in a
stainless steel crucible and placed on a hot plate in an argon atmosphere Temperature of the salt
is measured with a thermocouple immersed in the salt The temperature was held at 52315 K for
2 hours The salt solidifies to a white mass The temperature of the salt is then raised to 57315 K
slowly to remove any traces of moisture and to ensure complete dehydration The complete
removal of water is ascertained by weight loss
512 Apparatus and Procedure
31
Differential scanning calorimetry (DSC) analysis was performed using Perkin Elmer
Diamond DSC instrument and the setup is shown in fig 51 Heat flow and temperature can be
recorded in the instrument with an accuracy of 00001 mW and 001 K respectively The
measurements were made under purified nitrogen atmosphere with a flow rate of 20ccmin and at
a heating rate of 5 Kmin
Fig 51 Photography of set-up for DSC equipment
After dehydration if necessary each component was weighed to an accuracy of 01mg with
the electrical balance and mixed thoroughly in a stainless steel crucible Later the mixture is
heated up to certain temperature at which the entire salt melts At this temperature the salt
mixture was held for about 30 minutes The salt mixture is allowed to air cool to ambient
temperature This procedure is repeated 3 to 4 times to get the well-mixed compound Standard
aluminum pan with lid used for DSC measurements are weighed before the experiment Small
amount of the synthesized compound is placed carefully in the aluminum pan and closed with
the lid The lid is crimped by a sample press and the pan is weighed The weight of the sample is
32
determined by removing the weight of the pan and lid For the determination of melting point
and heat capacity (20-25) mg of the sample was used
Perkin-Elmer Diamond Differential Scanning Calorimeter (DSC) is used to measure the
melting point and heat capacity of compound The crimped ample pan was immediately put
inside the sample chamber of DSC after preparation and held at 52315 K for 10 hours to remove
the trace amount of moisture possibly caught in the process of loading sample and also to ensure
a homogeneous mixture In the experimental procedure a temperature range from 29815 K to
52315 K was set with a heating rate of 5 K min
1 followed by a cooling cycle at the same rate
This cycle is repeated for at least 6 times to ensure good mixture of the sample and
reproducibility of the results
52 Heat Capacity determination of molten salt mixtures
To start Cp measurement the same procedure as that of melting point determination is
followed with an addition of bdquoiso-scan-iso‟ steps to the program after 5-cycle temperature scan
Starting from 29815 K the temperature was held for 5 minutes before and after each scan step
Small temperature scan range is chosen to avoid thermal resistance between device and testing
sample except when the temperature is approaching the melting temperature The upper limit for
the Cp measurement was set to 62315 K in our experiments Since the change in the molar heat
capacity of the salt in the liquid state is very small the Cp data in the liquid state can be easily fit
to an equation and extrapolated to higher temperatures To get the value of molar heat capacity
of the sample heat flow curve for the baseline of the empty sample pan also needs to be obtained
immediately following the identical ldquoiso-scan-isordquo steps which were used for the actual sample
33
run The difference of heat flow between the actual crimpled sample and the empty sample pan is
the absolute heat absorbed by the test sample
53 Density determination of molten salt mixtures
Density measurement was carried out with standard densitometer which has fixed volume
Initial weight of the densitometer is measured and noted Salt composition of which the density
is measured is placed in a beaker on a hot place The densitometer is also placed on the same hot
plate The temperature is set to a fixed value above the melting point of the salt and is measured
by a thermocouple After the salt is melted and when the temperature shows stable reading the
molten salt is poured in to the densitometer up to the set mark on the sensitometer bottle The
weight of the densitometer with the molten salt is measured The weight difference between this
weight and the weight of empty densitometer gives the weight of the molten salt at the fixed set
temperature By knowing the fixed volume in the densitometer the density of the salt at that
temperature can be calculated This procedure is repeated at least three times to accurately
determine the density of the salt
34
CHAPTER 6
RESULT AND DISCUSSION
61 Melting point determination
611 DSC equipment calibration
Before the actual melting point measurement pure indium zinc metal and several
individual salts were used to calibrate the DSC equipment For metals only one sharp peak was
observed for each and the heat flow curve for indium metal is shown in fig 61 However larger
and boarder peaks are found for salts just like the condition illustrated in fig 62 for pure
potassium nitrate Based on the results shown in Table 61 the experimental data for melting
points and enthalpies of fusion have excellent agreement with the literature values [60-63] The
variation of point is within 07 and the variation of change of enthalpy is less than 3
Figure 61 Melting point calibration with indium sample
35
Figure 62 Melting point calibration with KNO3 sample
Table 61 Calibration data of melting points with different samples
Sample
Lit
Tmp
Expt
Tmp
Lit
Ttrans
Expt
Ttrans
Lit
ΔHfusion
Expt
ΔHfusion
Lit
ΔHtrans
Expt
ΔHtrans
degC degC degC degC Jg Jg Jg Jg
Indium 1566 1563 - - 286 278 - -
Zinc 4195 4188 - - 1086 1068 - -
LiNO3 2567 2550 - - 3617 3633 - -
NaNO3 3100 3081 2770 2753 1777 1756 147 152
KNO3 3370 3372 1330 1332 993 1005 538 529
612 Results
Differential scanning calorimetry (DSC) was used to determine the melting point and any
solid state phase transitions of the salt mixture A low scanning rate was chosen to record the
heat flow curve as function of temperature in order to improve the sensitivity of detection [64] It
helps to pick up any small endothermic peaks and also avoids the thermal resistance between the
36
internal furnace and sample Nine systems were chosen to test and the eutectic composition is
already listed in Table 41
All the selected systems are composed of alkaline nitrate and nitrite and most of them have
three basic components which are lithium sodium potassium nitrate or nitrite All the quaternary
and quinary systems were developed on the basis of the LiNO3-NaNO3-KNO3 baseline ternary
Figure 63-611 shows the DSC plot of all the salt systems DSC plots for each system were
collected for at least five runs (each run with fresh salt preparation) to ensure the reproducibility
All the onset temperatures peak temperatures predicted temperatures enthalpy of fusion for
melting peaks and the solid phase transformation temperatures are given in Table62
Figure 63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt
37
Figure 64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt
Figure 65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt
38
Figure 66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt
Figure 67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt
39
Figure 68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
Figure 69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
40
Figure 610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt
Figure 611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN salt
Table 62 illustrates that the predicted melting point is close to the experimental
determined value and most deviation is within 10 except for system 9 The great agreement
41
between experimental and calculated data verifies the accuracy and feasibility of the
thermodynamic modeling
Table 62 DSC results of melting point transition point and predicted melting point
System Tmp Ttrans ΔHfusion
Calculated degC Onset degC Peak degC Peak degC Jg
Salt 1 1160 994 1191 1043 600
Salt 2 1238 1150 1240 NA 97
Salt 3 986 940 999 NA 244
Salt 4 986 940 1010 NA 60
Salt 5 957 910 950 NA 62
Salt 6 1000 930 960 NA 86
Salt 7 1081 992 1003 793 60
Salt 8 1008 1010 1019 853 59
Salt 9 1036 834 892 NA 93
613 Discussion
It is observed that the first curve is different from last ones shown in the DSC plots and
this phenomenon is common for all the melting point measurement with DSC technique This
happened because in the first cycle the moisture caught by salt mixture especially the lithium
nitrate was removed in the process of heating Moreover the partially solidified sample in the
sample loading process can be re-homogenized in the first heating cycle [65-67] In figure 63
69 and 610 more than one endothermic peak was found The first smaller endothermic peak
refers to solid state phase transition of the salt mixture The second larger endothermic peak
refers to the melting of the salt Normally the onset temperature of transition is taken as the
experimental transition point for any metallic sample However in case of molten salts mixtures
since the thermal conductivity is low [68-74] the complete transition is ensured only at the peak
42
transition temperature The thermal gradient which exists due to the low thermal conductivity of
the salt results in internal heat flow which enhances the mixing in the salt Thus the transition
temperature is defined as the peak temperature of phase transition For salt No1 the small
endothermic peak happened before and was connected to the main peak which occurred at
39027K The first endothermic peaks for salt No 7 and 8 occurred at almost the same
temperature because of the similar composition for these two compounds Since the small
amount of magnesium nitrate and potassium nitrite contained in these two compounds the small
endothermic peak can hardly be related to these two components Obviously the rest three major
components must have something to do with the first peaks happened before the melting peaks
for both cases Each component among the major three ones were tested to find out any possible
solid phase transition peaks of them and the results shown in Table 63 which reveals that
lithium nitrate doesnt have any phase transition peak in solid state while potassium nitrate and
sodium nitrite both own the solid phase transformation peaks before their melting peaks
Table 63 Fusion and solid phase transition temperature for individual salts
System Tmp degC Ttrans degC ΔHfusion Jg ΔHtrans Jg
LiNO3 2550 - 3633 -
KNO3 3372 1332 1005 529
NaNO2 4311 4170 1119 880
The further investigation was carried out by running the KNO3-NaNO2 (550 wt and 238 wt )
binary compound with the very similar weight percentage as that in salt No 7 (546 wt and
237 wt) and salt No 8 (559wt and 239wt) By converting the weight percentage of the
studied binary system into 100 scale the weight fraction for sodium nitrate and potassium
nitrate can be rewritten as 698wt and 302wt The DSC plot for this binary system was
43
shown in fig 612 Although the solid transition and melting temperature were brought down by
adding lithium nitrate the shape of the plots in fig 69 and 610 are identical to that shown in fig
612 The enthalpy of solid state transformation of the binary salt was also converted to that in
both quaternary systems by using the weight fraction occupied by the binary system and the
comparable change of converted enthalpy between the binary system and two quaternary systems
indicates the relevance of the solid transition peaks in salt 7 and 8 to the combined effect of
potassium nitrate and sodium nitrite
Figure 612 DSC plot of 698wt KNO3- 302wt NaNO2 binary system
The similar analysis was applied to No1 salt to find out the reason for the presence of a
small peak adherent to the main melting peak before the melting point Sodium nitrate and
potassium nitrate binary system was synthesized based on the weight fraction of these two
constituent salts in No 1 salt DSC plot for the sodium nitrate-potassium nitrate binary system in
Fig 613 with the converted composition which is essentially same as that in the No1 ternary
system shows smooth heat flow curve before the melting peak which means the solid transition
peak in ternary is not simply relative to the binary system Assumption was made that the solid
44
phase transformation peak in the ternary salt is resulted from a multiple effect ie the
combination of one of the eutectic binary system involved in the ternary salt mixture and the
other binary system which is composed of the rest components The statement is verified that the
small peak in salt 1 is mainly caused by the solid phase transformation peak in lithium nitrate-
potassium nitrate eutectic binary system given the similar shape of the DSC plots in Fig 614
Since in salt No1 there is excess amount of sodium nitrate to form the lithium nitrate-sodium
nitrate binary system the rest sodium nitrate can interact with potassium nitrate and form new
sodium-potassium nitrate system which is shown in fig615 Besides a solid phase
transformation peak is observed in fig615 which has a very small area and won‟t change the
shape of phase transformation peak in fig614 when these two binary systems are combined and
form salt 1 The enthalpies of solid state transformation in two binary salts were also converted
to that in salt 1 by using the weight fractions occupied by both binary systems The difference
of the change of converted enthalpies between the lithium-potassium nitrate eutectic binary and
ternary system is filled by the binary mixture which is composed of the rest components sodium
nitrate-potassium nitrate The comparable converted values of enthalpy change between salt 1
and its two constituent binary systems further verify the assumption that the solid phase
transformation happened in salt 1 is mainly due to the combined effect of LiNO3-KNO3 eutectic
binary system and NaNO3-KNO3 binary system
45
Figure613 DSC plot of 270wt NaNO3-730wt KNO3 binary system
Figure614 DSC plot of 458wtLiNO3-542wtKNO3 binary system
46
Figure615 DSC plot of 460wt NaNO3-540wt KNO3 binary system
Unlike those discussed mixtures above salt No2 Salt No4 Salt No5 and Salt No6 have
only one relatively board melting peak and the heat flow curve before and after are very stable
Similarly there is no solid transformation peaks observed in salt No3 salt No7 and salt No8
However the heat flow after the melting peak in these cases are not stable and the main
endothermic peak is followed by a small hump which is considered to be the recrystallization
process once the compound entered into the liquid state When the process is finished the heat
flow curve returns to steady state
Heating rate is a significant parameter when collect the heat flow curves by using DSC
technique Fig 616(a) and Fig 616(b) illustrate the difference of melting point for salt No6 due
to the change of heating rate If the heating rate is 20oCmin the peak temperature and onset
temperature for the melting peak is 9669oC and 9221
oC respectively Once the heating rate is
decreased to 5oCmin these two temperatures will also be lowered to 9614
oC and 9190
oC The
difference is resulted from the diverse amount of thermal resistance between the testing sample
and the furnace inside the DSC instrument [75] Under higher heating rate the decisive thermal
47
resistance is raised due to the low thermal conductivity medium between the furnace and the
actual sample The insensitivity of gas heat conduction medium in DSC results each unit of
temperature increase on one side cannot have an immediate response on the other side of the gas
Consequently the sample holder which is connected the furnace has a higher temperature than
that inside the sample In this condition the value of temperature profile collected as the sample
holder temperature is larger than the actual temperature The deviation will be much smaller
when the heating rate is reduced In the case the thermal resistance will be decreased because of
the lower temperature gradient of the gas medium in the heating process As a result of that the
collected temperature from the sensor attached to the sample holder will be very close to the
actual temperature inside the testing sample
Figure 616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 20oCmin
heating rate
48
Figure 616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 5oCmin
heating rate
Besides the difference of temperature while using higher and lower heat rate the solution
of DSC will also be affected by different heating rate Fig 617(a) shows the DSC plot for salt
No 7 using the heating rate as 5oCmin and the DSC plot in Fig 617(b) is collected under the
heating rate as 20oCmin It can be observed that in the lower heating rate two small separated
peaks can be viewed as two parts of the solid phase transformation process while in Fig 617(b)
two small peaks before the melting peak merge and present as a board hump The qualification
of resolution can be executed by the term named resolution factor RMKE which is calculated as
the ratio of the peak heat flow value of the separated peaks to that of the concave point between
two peaks The equation for determining RMIKE is given in Eq 27 [76 77]
RMIKE =hpeakhmin [27]
49
Figure 617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 5oCmin
heating rate
Figure 617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 20oCmin
heating rate
In the case of lower heating rate the RMKE is determined to be 15 and the value for higher
heating rate is not available because the concave point of heat flow doesn‟t exist from
Fig617(b) Since the higher RMKE value indicates better resolution it can be stated that the
50
lower heating rate also results in greater sensitivity of the equipment to pick up any small
endothermic peaks
Besides the down-selected 9 compounds some more salt mixtures were also tested Most
of them were not selected to the final candidate for the thermal energy storage application
because of their higher melting point Table 64 gives some of the trial systems measured with
DSC technique It is illustrated that the melting points of mixtures with lower or even no content
of lithium nitrate turn out to be higher than those with sufficient amount of lithium nitrate For
most of the mixtures with melting point lower than 120oC the amount of lithium nitrate should
be larger than 81wt Also all of the systems in table 64 with lithium nitrate less than 15wt
have melting point higher than 140oC Based on the observation above it is concluded that the
lithium nitrate can be used as an additive to bring the melting point down for thermal energy
storage systems
51
Table 64 Melting points of candidate systems as function of temperatures
System Composition (wt)
Onset
Temp
Peak
Temp
(oC) (
oC)
LiNO3 ndash NaNO3 ndash KNO2 107 459 434 890 910
LiNO3 - KNO3 - NaNO2 196 564 241
1024 1046
LiNO3 - NaNO3 - KNO3 - KNO2 90 423 337 151
930 960
LiNO3 - NaNO3 - NaNO2 - KNO2 81 454 65 401
900 910
LiNO3 - KNO3 - NaNO2 - KNO2 193 546 237 24
992 1003
LiNO3 - KNO3 - NaNO2 ndash Mg(NO3)2 193 559 238 09
1010 1020
LiNO3 - NaNO3 - KNO3 - Mg(NO3)2
- MgK 154 172 324 83 267 834 892
LiNO3 - NaNO3 - KNO2 ndash Ca(NO3)2 14 390 333 263
1250 1470
NaNO3 - KNO3 - NaNO2 - KNO2 425 163 71 341
1407 1447
NaNO3 - KNO3 - KNO2 ndash Mg(NO3)2 432 146 380 42
1386 1421
NaNO3 - NaNO2 - KNO2 - Ca(NO3)2 451 92 410 48
1150 1390
LiNO3 - NaNO3 - NaNO2 - KNO2 -
Ca(NO3)2 15 393 37 323 232 1380 1480
LiNO3 - NaNO3 - KNO2 - Ca(NO3)2 -
Mg(NO3)2 14 379 313 275 20 1339 1534
62 Heat capacity determination
621 Heat capacity calibration
DSC was also calibrated for the heat capacity measurement Lithium nitrate sodium
nitrate and potassium nitrate were examined for the heat capacities from room temperature to
upper limit temperature for the instrument In liquid state the heat capacity values for each salt
can be fit to straight line with trace amount of increasing trend Since the temperature range from
the onset temperature of liquid state to the upper limit of DSC is relatively small the heat
capacity values for pure individual salts can be viewed as constants The comparison between the
theoretical and experimental heat capacity data is given in Table 65 Except lithium nitrate the
52
experimental heat capacities data for the rest two systems are almost same as the literature Even
for lithium nitrate which demonstrates the biggest difference from the literature data the 28
vibration is still within a reasonable range
Table 65 Calibration data of heat capacities with different samples
Sample Lit Cp Expt Cp
JgK JgK
LiNO3 218 212
NaNO3 169 167
KNO3 140 139
622 Results
The materials used in the heat capacity measurements are the same as those in the melting
point experiments Molar heat capacities of the all compound were measured by the DSC
equipment from room temperature to 62315 K The heat flow is recorded as a function of
temperature in ldquoiso-scan-isordquo steps at intervals of 20 K The bdquoiso stage‟ refers to isothermal
holding at a particular temperature bdquoscan stage‟ refers to the heat flow recording at a heating rate
of 5 K min1
up to a an increment of 25 K followed by another isothermal holding stage This is
a standard procedure followed in the measurement of heat capacity of materials using the DSC
equipment [63 64] This procedure of heat capacity measurement has two advantages (i) any
heat fluctuations during the recording are avoided by the isothermal steps and (ii) any phase
transition can be highlighted by the choice of temperature range The absolute heat flow to the
sample is determined by subtracting the heat flow collected by running a baseline curve with an
empty pan Because the heat capacity measurement in the heating process corresponds to
53
collecting the value of required heat flow at each temperature all the heat capacity plots have the
same shape with that of heat flow in the melting point measurements Take the heat capacity plot
of LiNO3-NaNO3-KNO3 ternary system as an instance which is shown in fig 618 the heat
capacity curve also has two different peaks The first little peaks corresponds to one occurs at
39027K which was observed in fig 63 the second large and sharp peak happened right after the
small one is prevalent to the endothermic peak with the peak temperature as 39027 K Similarly
after the phase transformation the heat capacity in liquid state becomes very stable and increase
with temperature linearly with little slope
Fig 618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system as function of
temperature
The heat capacity change as function of temperature for salt No1 was illustrated in fig
619 Based on the trend of heat capacity in the liquid state any value for the system in the liquid
can be extrapolated The expressions for heat capacity in liquid state for the new molten salt
systems were discussed and given in the next sectionTable66 shows the specific heat capacity
54
of the all the selective compounds measured at 62315 K and extrapolated at 77315K Besides
the molar heat capacities at 77315K are given in Table 66 of all the salts
Fig 619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K
Table 66 Heat capacity of selected new TES molten salt mixtures
System Expt (62315K) Extrapolated(77315K) Extrapolated(77315K)
Cp JgK Cp JgK Molar Cp JmolK
Salt 1 153 170 1521
Salt 2 143 168 1515
Salt 3 148 155 2183
Salt 4 153 166 1411
Salt 5 153 170 1440
Salt 6 151 163 1435
Salt 7 156 167 1443
Salt 8 155 168 1410
Salt 9 161 170 1937
55
623 Thermodynamic properties
The standard thermodynamic properties such as entropy enthalpy and Gibbs energy for
salt mixtures are determined from the experimental data of melting point and heat capacity in the
temperature range of the present study and expression for determining these properties are given
in equation 28-30 In thermodynamics all these three properties are related to heat capacity and
its variances with temperature In the studied temperature range (29815K-62315K) they can be
described as expression includes heat capacity
[28]
[29]
[30]
Where Tt is the solid transformation temperature Tmp is the melting point ΔHt is enthalpy of
solid phase transformation and ΔHfusion is enthalpy of fusion The standard thermodynamic
properties entropy enthalpy and Gibbs energies as function of temperature for each compound
are expressed in the following section
6231 LiNO3-NaNO3-KNO3 (Salt 1)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3
compound (i) solid state 1 (32315-38415) K (ii) liquid state (40315-62315) K Accordingly
56
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62311 Heat capacity of solid state 1 (29815-38415) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the solid state 1 in the
temperature range of 29815 to 38415 K is fit to a second order polynomial equation Eqn (31)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[31]
( ) K
R2 = 0982
62312 Heat capacity of liquid state (40315-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a linear equation Eqn (32) gives the linear
equation along with the least square fit parameter (R2) in the temperature range for the liquid
state of the compound
JKmol [32]
57
R2 = 0947
Heat capacity data of the LiNO3-NaNO3-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62313 Thermodynamic properties of solid state 1(29815-38415) K
JKmol [33]
Jmol [34]
[35]
Jmol
62314 Thermodynamic properties of liquid state 2(40315-62315) K
[36]
58
JKmol
Jmol [37]
[38]
Jmol
Among the equations above equation (33)-(35) refer to the thermodynamic properties for
solid state equations (36)-(38) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature ranges for solid and liquid state are
given in Table A1 and A2 in appendix A respectively with the corresponding heat capacity as
function of temperature
6232 NaNO3-NaNO2-KNO3 (Salt 2)
The heat capacity data can be divided into two sections for NaNO3-NaNO2-KNO3
compound (i) solid state 1 (32315-39215) K (ii) liquid state (41315-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62321 Heat capacity of solid state 1 (29815-39215) K
59
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the solid state in the
temperature range of 29815 to 39215 K is fit to a second order polynomial equation Eqn (39)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[39]
( ) K
R2 = 0978
62322 Heat capacity of liquid state (40315-62315) K
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a second order polynomial equation Eqn (40)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[40]
R2 = 0941
60
Heat capacity data of the NaNO3-NaNO2-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62323 Thermodynamic properties of solid state 1(29815-39215) K
JKmol [41]
Jmol [42]
[43]
Jmol
62324 Thermodynamic properties of liquid state 2(40315-62315) K
JKmol [44]
61
Jmol [45]
[46]
Jmol
Among the equations above equation (41)-(43) refer to the thermodynamic properties for
solid state equations (44)-(46) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table B1 and B2 in appendix B respectively with the corresponding heat capacity as
function of temperature
6233 LiNO3-NaNO3 -KNO3-MgK (Salt 3)
The heat capacity data can be divided into two sections for LiNO3-NaNO3 -KNO3-MgK
compound (i) solid state 1 (29815-36415) K (ii) liquid state (42115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62331 Heat capacity of solid state 1 (29815-36415) K
62
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the solid state in the
temperature range of 29815 to 36415 K is fit to a second order polynomial equation Eqn (47)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[47]
( ) K
R2 = 0995
62332 Heat capacity of liquid state (42115-62315) K
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the liquid state in the
temperature range of 42115 to 62315 K is fit to a second order polynomial equation Eqn (48)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[48]
R2 = 0963
63
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
62333 Thermodynamic properties of solid state 1(29815-36415) K
JKmol [49]
Jmol [50]
[51]
Jmol
62334 Thermodynamic properties of liquid state 2(42115-62315) K
64
JKmol [52]
Jmol [53]
[54] [29]
Jmol
Among the equations above equation (49)-(51) refer to the thermodynamic properties for
solid state equations (52)-(54) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table C1and C2 in appendix C respectively with the corresponding heat capacity as
function of temperature
6234 LiNO3-NaNO3-KNO3-NaNO2 (Salt 4)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-NaNO2
compound (i) solid state 1 (29815-36315) K (ii) liquid state (38115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62341 Heat capacity of solid state 1 (29815-36315) K
65
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the solid state in the
temperature range of 29815 to 36315 K is fit to a second order polynomial equation Eqn (55)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[55]
( ) K
R2 = 0995
62342 Heat capacity of liquid state (38115-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the liquid state in the
temperature range of 38115 to 62315 K is fit to a second order polynomial equation Eqn (56)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[56]
R2 = 0972
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
66
62343 Thermodynamic properties of solid state 1(29815-36315) K
JKmol [57]
Jmol [58]
[59]
Jmol
62344 Thermodynamic properties of liquid state 2(38115-62315) K
JKmol [60]
Jmol [61]
67
[37]
Jmol [62]
Among the equations above equation (57)-(59) refer to the thermodynamic properties for
solid state equations (60)-(62) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table D1 and D2 in appendix D respectively with the corresponding heat capacity as
function of temperature
6235 LiNO3-NaNO3-NaNO2-KNO3-KNO2 (Salt 5)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-NaNO2-KNO3-
KNO2 compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62351 Heat capacity of solid state 1 (29815-35915) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
in the temperature range of 29815 to 35915 K is fit to a second order polynomial equation Eqn
(63) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
68
[63]
( ) K
R2 = 0996
62352 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the liquid
state in the temperature range of 37515 to 62315 K is fit to a second order polynomial equation
Eqn (64) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[64]
R2 = 0969
Heat capacity data of the LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62353 Thermodynamic properties of Solid state 1(29815-35915) K
JKmol [65]
69
Jmol [66]
[67]
Jmol
62354 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [68]
Jmol [69]
[45]
Jmol [70]
70
Among the equations above equation (65)-(67) refer to the thermodynamic properties for
solid state equations (68)-(70) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table E1 and E2 in appendix E respectively with the corresponding heat capacity as
function of temperature
6236 LiNO3-NaNO3-KNO3-KNO2 (Salt 6)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-KNO2
compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62361 Heat capacity of solid state 1 (29815-36515) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the solid state in the
temperature range of 29815 to 36515 K is fit to a second order polynomial equation Eqn (71)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[71]
( ) K
R2 = 0998
71
62362 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the liquid state in the
temperature range of 37515 to 62315 K is given in Table 20 The data is fit to a second order
polynomial equation Eqn (72) gives the linear equation along with the least square fit parameter
(R2) in the temperature range for the liquid state of the compound
[72]
R2 = 0953
Heat capacity data of the LiNO3-NaNO3-KNO3-KNO2 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62363 Thermodynamic properties of solid state 1(29815-35915) K
JKmol [73]
Jmol [74]
72
[75]
Jmol
62364 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [76]
Jmol [77]
Jmol [78]
Among the equations above equation (73)-(75) refer to the thermodynamic properties for
solid state equations (76)-(78) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
73
given in Table F1 and F2 in appendix F respectively with the corresponding heat capacity as
function of temperature
6237 LiNO3-KNO3-NaNO2-KNO2 (Salt 7)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62371 Heat capacity of solid state 1 (29815-35415) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 1 in
the temperature range of 29815 to 35415 K is fit to a second order polynomial equation Eqn
(79) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[79]
(29815-35415) K
R2 = 0993
62372 Heat capacity of solid state 2 (36215-37315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 2 in
the temperature range of 36215 to 37315 K is fit to a second order polynomial equation Eqn
74
(80) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 2 of the compound
[80]
R2 = 0977
62373 Heat capacity of liquid state (37915-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the liquid state in the
temperature range of 37915 to 62315 K is fit to a linear equation Eqn (81) gives the
polynomial equation along with the least square fit parameter (R2) in the temperature range for
the liquid state of the compound
[81]
R2 = 0961
Heat capacity data of the LiNO3-KNO3-NaNO2-KNO2 compound in the two solid states
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62374 Thermodynamic properties of solid state 1(29815-35415) K
75
JKmol [82]
Jmol [83]
[84]
Jmol
62375 Thermodynamic properties of solid state 2(36215-37315) K
JKmol [85]
Jmol [86]
76
[87] [62]
Jmol
62376 Thermodynamic properties of liquid state (37915-62315) K
JKmol [88]
Jmol [89]
Jmol [90]
Among the equations above equation (82)-(84) refer to the thermodynamic properties for
solid 1 equation (85)-(87) refer to the thermodynamic properties for solid 2 equations (88)-(90)
refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy values
77
in the studied temperature range for solid 1 solid 2 and liquid state are given in Table G1-G3 in
appendix G respectively with the corresponding heat capacity as function of temperature
6238 LiNO3-KNO3-NaNO2-Mg(NO3)2 (salt 8)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62381 Heat capacity of solid state 1 (29815-33715) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid
state 1 in the temperature range of 29815 to 33715 K is fit to a second order polynomial
equation Eqn (91) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the solid state 1 of the compound
[91]
(29815-33715) K
R2 = 0994
62382 Heat capacity of solid state 2 (36115-36415) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid state 2
in the temperature range of 36115 to 36415 K is given in Table 4 The data is fit to a second
78
order polynomial equation Eqn (92) gives the polynomial equation along with the least square
fit parameter (R2) in the temperature range for the solid state 2 of the compound
[92]
R2 = 0992
62383 Heat capacity of liquid state (41115-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the liquid state in
the temperature range of 41115 to 62315 K is given in Table 5 The data is fit to a linear
equation Eqn (93) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the liquid state of the compound
[93]
R2 = 0934
Heat capacity data of the LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the two solid
states follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62384 Solid state 1(29815-35415) K
79
JKmol [94]
Jmol [95]
[96]
Jmol
62385 Solid state 2(36115-36415) K
JKmol [97]
80
Jmol [98]
[99] [74]
Jmol
62386 Liquid state (41115-62315) K
JKmol [100]
Jmol [101]
Jmol [102]
Among the equations above equation (94)-(96) refer to the thermodynamic properties for
solid 1 equation (97)-(99) refer to the thermodynamic properties for solid 2 equations (100)-
(102) refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy
81
values in the studied temperature range for solid 1 solid 2 and liquid state are given in Table H1
and H2 in appendix H respectively with the corresponding heat capacity as function of
temperature
6239 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK(Salt 9)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-
Mg(NO3)2-MgK compound (i) solid state 1 (29815-35315) K (ii) liquid state (39115-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62391 Heat capacity of solid state 1 (29815-35315) K
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state in the temperature range of 29815 to 35315 K is fit to a second order polynomial equation
Eqn (103) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[103]
( ) K
R2 = 0996
62392 Heat capacity of liquid state (39115-62315) K
82
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the liquid
state in the temperature range of 39115 to 62315 K is fit to a second order polynomial equation
Eqn (104) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[104]
R2 = 0951
Heat capacity data of the LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62393 Solid state 1(29815-35315) K
JKmol [105]
Jmol [106]
83
[107]
Jmol
62394 Liquid state 2(39115-62315) K
JKmol [108]
Jmol [109]
[110]
Jmol
Among the equations above equation (105)-(107) refer to the thermodynamic properties
for solid state equations (108)-(110) refer to thermodynamic properties of the liquid The
entropy enthalpy and Gibbs energy values in the studied temperature range for solid and liquid
state are given in Table I1 and I2 in appendix I respectively with the corresponding heat
capacity as function of temperature
84
624 Discussion of Gibbs energy change for molten salts
The Gibbs energy change data as function of temperature for 9 systems are given in fig
620 and the values at 62315K are shown in Table 67 Every system demonstrates continuous
curve throughout the whole studied temperature range Most of systems have similar Gibbs
energy change values for each temperature spot due to the comparable compositions and
properties of constituent salts However salt 3 and salt 9 Both of these salts have certain
amount of MgKN compound which presents large absolute amount of change of Gibbs energy in
the same studied temperature range [66] Since the change of Gibbs energy for multi-component
mixture is relevant to that of each constituent salt the large absolute value of ΔG of MgKN
mainly contributes to the largely negative value of salt 3 and salt 9 shown in fig 620 Besides
it is observed that most systems contain nitrite salts present lower absolute value of Gibbs energy
change For example salt 1 doesn‟t include any nitrite salt and has a relatively high absolute
value of Gibbs energy change as 1704kJmol while other systems having nitrite salts show lower
value varies from 1372kJmol to 1592kJmol
85
Fig 620 Change of Gibbs energy as function of temperature for molten salt systems
Table 67 Change of Gibbs energy values at 62315K for molten salt systems
SNo System ΔG(kJmol)
1 LiNO3-NaNO3-KNO3 1704
2 NaNO3- NaNO2- KNO3 1372
3 LiNO3- NaNO3- KNO3- MgKN 2807
4 LiNO3- NaNO3- KNO3- NaNO2 1443
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1441
6 LiNO3-NaNO3-KNO3-KNO2 1570
7 LiNO3-KNO3-NaNO2-KNO2 1592
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1583
9 LiNO3-NaNO3-KNO3-Mg(NO3)2 -MgKN 2217
86
63 Density determination
631 Density calibration
Several pure molten salts are used to calibrate the density measurement set-up before the
actual density measurement All the density values decrease as function of temperature in the
liquid state and follow the same linear equations as described in eq 4 The experimental values
at 350oC for KNO3 NaNO3 and LiNO3 are selected to compare with the literature data at the
same temperature The results are shown in Table 68 Based on the comparison of the literature
data and the experimental data the variation of density for molten nitrate salt is within in 4
Table 68 Calibration of density measurements with different pure nitrate salts
Sample Literature density Experimental density
gcm3 gcm
3
LiNO3 1727 1701
NaNO3 2066 2144
KNO3 1860 1855
632 Results and discussions
The density result of the salt as function of temperature is plotted for all the salts in Figure
621 and Figure 622 It is observed that the temperature dependence of density above the
melting point is different from that in solid state As known in solid state the density of salt has
an exponential relation with temperature while in these liquid cases the density values have
linearly dependence with temperature The stable variation as function of temperature allows the
extrapolation of density at even higher temperature The regression analysis is performed to get
the coefficient used for describing eq 4 and the results for the coefficients are shown in
87
Table69 [78-80] It is observed that the change of composition is implied on the coefficient A
which indicates the initial point at 150oC The temperature dependence coefficient B doesn‟t
change much with composition which may be mainly affected by the group of anion and cation
Table 69 Coefficient A and B for density determination of salt 1-salt 9
Salt No System A Btimes10
3
(gcm3) (gcm
3degC)
1 LiNO3-NaNO3-KNO3 2032 0493
2 NaNO3- NaNO2- KNO3 2081 0570
3 LiNO3- NaNO3- KNO3-MgKN 2055 0526
4 LiNO3- NaNO3- KNO3- NaNO2 2033 0520
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 2018 0485
6 LiNO3-NaNO3-KNO3-KNO2 2060 0554
7 LiNO3-KNO3-NaNO2-KNO2 2048 0554
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 2044 0524
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 2060 0566
Figure 621 The densities of the salt 1-salt 5 as function of temperature
88
In figure 621 all the density values are clustered around 198gcm3 at 150
oC to
186gcm3 at high temperature end and the deviation of density between all the mixtures is within
in 0047g cm3 Among all the salt mixtures the NaNO3-NaNO2-KNO3 ternary system
demonstrates the highest density value throughout the studied temperature range and LiNO3-
NaNO3-KNO3 ternary system LiNO3- NaNO3-KNO3-NaNO2 quaternary system and LiNO3-
NaNO3-KNO3-NaNO2-KNO2 quinary system show densities at the bottom side of Fig 621 For
salt 2 which doesn‟t contain any lithium nitrate the density at every selected temperature spot
is obviously higher than that of salt 1 4 and 5 which have large amount of lithium nitrate
Moreover the salt 3 which contains the relatively small amount of lithium nitrate stays in
between of salt 1 and salt 2 This comparison illustrates that the addition of lithium nitrate has
an offsetting effect on density for molten salt and it is consistent with previous literature reports
[81] The four systems presented in figure 622 also show even closer density values in the
studied temperature range Similarly salt 6 which contains the least lithium nitrate has the
largest density Salt 7 and salt 8 have almost same composition for the three dominating
components as a result of that the density curves for both mixtures are determined by the same
regression coefficient A and B Moreover the larger amount of lithium nitrate involved in these
two salt mixtures contributes to the lower density given in figure622 which further verifies the
significantly offsetting effect of lithium nitrate on density
89
Figure 622 The densities of the salt 6-salt 9 as function of temperature
The salt mixtures with maximum and minimum amount of lithium nitrate were plotted and
compared with equimolar NaNO3-KNO3 binary system and pure KNO3 salt in Fig623 [82 83]
It is observed that the NaNO3-KNO3 binary system has very similar density value to that of salt
2 because of the analogous type and composition of component in both salts The density of
pure KNO3 is slightly lower than the binary salt mixture which indicates the density of NaNO3 is
close to but higher than KNO3 in the studied temperature range Salt 1 shows the lowest density
in Fig623 due to the offsetting effect on density caused by lithium nitrate which has been
discussed above
90
Figure 623 Density of the salt 1 salt 2 as function of temperature compared to the
equimolar NaNO3-KNO3 binary system and pure KNO3
64 Thermal energy storage density of molten salts
The energy density which is considered as one of the most significant parameters of TES
application can be evaluated by calculation based on the measured density heat capacity and
working temperature range The equation of the thermal energy storage density (E) at working
temperature of 500oC is expressed in equation 111
E = Cp (500-Tm) [111]
Where Cp and are extrapolated heat capacity and density at 500oC respectively Tm is
melting point for salt mixture The extrapolation of density and heat capacity is based on the
linear temperature dependence for both parameters in molten state and the values are shown in
Table 610
91
Table 610 Extrapolated value of density and heat capacity at 500oC of salt 1-salt 9
Salt
No System
Density Heat Capacity
(gmL) (JgK)
1 LiNO3-NaNO3-KNO3 1785 170
2 NaNO3- NaNO2- KNO3 1796 168
3 LiNO3-NaNO3-KNO3-MgK 1773 155
4 LiNO3- NaNO3- KNO3- NaNO2 1792 166
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1796 170
6 LiNO3-NaNO3-KNO3-KNO2 1783 163
7 LiNO3-KNO3-NaNO2-KNO2 1771 167
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1782 168
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 1777 170
The calculated energy density for each salt is given in Table 611 compared with that of
solar salt (NaNO3-KNO3) All the new synthesized salt mixtures have significantly higher energy
density than solar salt and salt 3 shows the highest energy density among the new salts
Although salt 1 has higher heat capacity and good melting point the energy density is still the
lowest among new salt mixtures given by the effect of low density The conclusion can be drawn
from these observations that the energy density is a property affected by multiple parameters and
every part plays an important role in determining the efficiency of energy storage of salt
mixtures
92
Table 611 Energy density of salt 1-salt 9 compare to solar salt
The gravimetric storage density of new molten salts are listed in Table 612 and compared
with those different storage systems in fig 624 It is found that in the parabolic trough working
temperature range the gravimetric storage densities of new molten salts are located on the higher
side Even though some reported sensible energy storage liquids have larger gravimetric density
values than the new salts the maximum working temperatures reveal the instable working
condition at 500oC Taking conversion efficiency thermal stability and gravimetric storage
density into considerations the new molten salts are the most suitable choices of the sensible
heat storage for parabolic trough application
Salt No System Energy Density
500degC (MJm3)
0 NaNO3- KNO3 756
1 LiNO3-NaNO3-KNO3 1162
2 NaNO3- NaNO2- KNO3 1135
3 LiNO3-NaNO
3-KNO
3-MgKN 1099
4 LiNO3- NaNO
3- KNO
3- NaNO
2 1189
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1232
6 LiNO3-NaNO3-KNO3-KNO2 1174
7 LiNO3-KNO3-NaNO2-KNO2 1183
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1192
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 1242
93
Fig 624 Gravimetric storage density comparison of different energy storage systems as
function of temperature
Table 612 Gravimetric storage densities for solar salt and new molten salts
Salt
No System
Gravimetric Storage Density
500degC (kJkg)
0 NaNO3- KNO3 404
1 LiNO3-NaNO3-KNO3 560
2 NaNO3- NaNO2- KNO3 533
3 LiNO3-NaNO
3-KNO
3-MgKN 575
4 LiNO3- NaNO
3- KNO
3- NaNO
2 612
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 595
6 LiNO3-NaNO3-KNO3-KNO2 594
7 LiNO3-KNO3-NaNO2-KNO2 604
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 610
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 649
94
CHAPTER 7
CONCLUSION
The melting points of new molten salts were experimentally determined using DSC
Different from metals the melting point was chosen as the peak temperature rather than onset
temperature of the endothermic peak due to the low thermal conductivity and broad phase
transition range of the molten nitride salt mixture All of the nine new molten salts have melting
points from 89oC to 124
oC which are much lower than current sodium-potassium binary solar
salt Some systems such as salt No1 No7 and No8 have solid phase transformation observed
from the DSC plots It is found that the phase transformations of salt No 7 and No 8 are mainly
contributed to the KNO3-NaNO2 binary system while the small solid transformation peak of salt
No1 is resulted from the combined effect of the KNO3-LiNO3 eutectic binary system involved in
the ternary salt and another binary system which is composed of the rest components The
heating rate of DSC was revealed as a significant parameter for the any endothermic peak
determination When using lower heating rate the thermal resistance between the studied sample
and the furnace will be minimal and the resolution of peak detection will be enhanced
The heat capacities of all the multi-component salts (1 to 9) were determined using DSC
and found varying from 143 to 161 JgK at 350oC The heat capacity in the liquid state
demonstrates linear increase trend as function of temperature On the basis of that the heat
capacity was extrapolated to parabolic trough operating temperature of 500oC Besides heat
capacity data as function of temperature are fit to polynomial equation and thermodynamic
95
properties like enthalpy entropy and Gibbs energies of the compound as function of temperature
are subsequently deduced
Experimental measurements of density of multi-component systems were conducted as
function of temperature in their liquid state In liquid state the density values decrease linearly
as temperature increases The results of those mixtures were compared to the solar salt and
individual constituent salts The comparison demonstrates that the addition of lithium nitrate
lowers the density which is consistent with the observation that lithium nitrate has the lowest
density among all the individual salts in the studied temperature range On the basis of densities
heat capacities and the melting points energy storage density for all the new salts were
calculated and compared to the binary solar salt Among all the new molten salt systems
LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN quinary system (salt 9) presents the largest thermal
energy storage density as well as the gravimetric density values Moreover the larger thermal
energy storage as well as gravimetric storage densities compared to the solar salt indicate the
better energy storage capacities of new salts for solar power generation systems
96
REFERENCES
[1] JF Manwell JG McGowan and AL Rogers Wind Energy Explained-Theory Design and
Application second edition John Wiley and sons Ltd UK 2009
[2] MJ Pasqualetti Morality space and the power of wind-energy landscapes Geographical
Review 90 2000 381-394
[3] DG Fink and HW Beaty Standard Handbook for Electrical Engineers Eleventh Edition
McGraw-Hill New York 1978
[4] R Bertani Geothermal Energy An Overview on Resources and Potential Proceedings of the
International Conference on National Development of Geothermal Energy Use 2009 Slovakia
[5] TA Volk LP Abrahamson EH White E Neuhauser E Gray C Demeter C Lindsey J
Jarnefeld DJ Aneshansley R Pellerin and S Edick Developing a Willow Biomass Crop
Enterprise for Bioenergy and Bioproducts in the United States Proceedings of Bioenergy
2000 October 15-19 2000 Buffalo New York USA
[6] M Asplund N Grevesse and AJ Sauval The new solar abundances-Part I the
observations Communications in Asteroseismology 147 2006 76-79
[7] DRWilliams Sun Fact Sheet NASA 2004
httpnssdcgsfcnasagovplanetaryfactsheetsunfacthtml
[8] U Herrmann Survey of Thermal Energy Storage for Parabolic Trough Power Plants Journal
of Solar Energy Engineering 124 2002 145-152
[9] Rocket Research Company Chemical energy storage for solar thermal conversion SAND79-
8198 Livermore Sandia National Laboratories 1979
97
[10] A Steinfeld and R Palumbo Solar thermochemical process technology Encyclopedia of
Physical Science and Technology 2001 237-256
[11] EA Fletcher Solar thermal processing a review Journal of Solar Energy Engineering
2001 63-74
[12] R W Bradshaw and Nathan P Siegel Molten Nitrate Salt Development for Thermal
Energy Storage in Parabolic Trough Solar Power Systems of the Energy Sustainability 2008
Conference August 10-14 2008 Jacksonville Florida USA
[13] B Kelly H Price D Brosseau and D Kearney Adopting NitrateNitrite Salt Mixtures as
the Heat Transport Fluid in Parabolic Trough Power Plants Proceedings of the Energy
Sustainability 2007 Conference June 27-30 2007 Long Beach CA
[14] H Reilly and G Kolb Evaluation of Molten Salt Power Tower Technology Based on
Experience at Solar Two SAND2001-3674 Sandia National Laboratories 2001
[15] T Wendelin ldquoParabolic Trough VSHOT Optical Characterization in 2005-2006rdquo NREL
wwwnrelgovdocsfy06osti40024pdf
[16] RB Diver C Andraka S Rawlinson V Goldberg and G Thomas The Advanced Dish
Development System Project ASME Proceedings of Solar Forum 2001 Washington DC
[17] S D Odeh G L Morrison and M Behnia Modelling of parabolic trough direct steam
generation solar collectors Solar Energy 62 1998 396-406
[18] V Heinzel H Kungle and M Simon Simulation of a parabolic trough collector ISES
Solar World Congress Harare Zimbabwe 1-10
[19] S D Odeh G L Morrison and M Behnia Modeling of Parabolic Trough Direct
Generation Solar Collectors Solar Energy 62 1998 395-406
[20] Ezzat Optimum Working Fluids for Solar Powered Rankine Cycle Cooling of Buildings
Solar energy 25 1980 235-241
98
[21] R G Reddy Ionic Liquids How well do we know them editorial Journal of Phase
Equilibria and Diffusion 27 2006 210-211
[22] M Zhang and R G Reddy Application of [C4min][Tf2N] Ionic Liquid as Thermal
Storage and Heat Transfer Fluids editor J Weidner ECS Transactions 2 (28) 2007 27-32
[23] M Zhang and R G Reddy Evaluation of Ionic Liquids as Heat Transfer Materials in
Thermal Storage Systems Energy Energy Materials editors F Dogan M Awano D Singh
and B Tuttle ASM International Materials Park Ohio USA MSampT‟07 2007 151-160
[24] R G Reddy Novel Applications of Ionic Liquids in Materials Processing Advanced
Structural and Functional Materials Design 2008 Journal of Physics Conference Series (JPCS)
165 2009 1-6
[25] RW Bradshaw and DE Meeker High-temperature stability of ternary nitrate molten
salts for solar thermal energy systems Solar Energy Materials 21 1990 51-60
[26] AS Trunin Designing and investigations of salt systems for solar energy utilization
Utilization of sun and other radiation sources in materials research Kiev Naukova Dumka 1983
p 228-38
[27] D J Rogers and G J Janz Melting-crystallization and premelting properties of sodium
nitrate-potassium nitrate Enthalpies and heat capacities Journal of Chemical and Engineering
Data 27 1982 424-428
[28] D Kearney U Herrmann P Nava and B Kelly Assessment of a molten salt heat transfer
fluid in a parabolic trough solar field Journal of Solar Energy Engineering 125 2003 170-176
[29] Q Peng J Ding X Wei J Yang and X Yang The preparation and properties of multi-
component molten salts Applied Energy 87 2010 2812-2817
[30] E M Levin C R Robbins and H F McMordie Phase Diagrams for Ceramists American
Ceramic Society 1964
[31] J C Oxley J L Smith E Rogers and M Yu Ammonium nitrate thermal stability and
explosivity modifiers Thermochimica Acta 384 2002 23-45
99
[32] LG Marianowski and HC Maru Latent heat thermal energy storage systems above
4508oC Proceedings of 12th intersociety energy conversion engineering conference 1977 55-
66
[33] HC Maru JF Dullea A Kardas L Paul LG Marianowski E Ong et al Molten salts
energy storage systems Chicago Final Report of the Institute of Gas Technology 1978
[34] WM Philips and JW Stears Advanced latent heat of fusion thermal energy storage for
solar power stations Proceedings of 20th intersociety energy conversion engineering conference
2 1985 384-391
[35] KE Mayo Heat source systems USA Patent 3605720 1971
[36] JI Eichelberger and HD Gillman Investigation of metal fluoride thermal energy storage
material Proceedings of 12th intersociety energy conversion engineering conference 1977 567-
574
[37] GR Heidenreich and MB Parekh Thermal energy storage for organic Rankine cycle solar
dynamic space power systems Proceedings of 21st intersociety energy conversion engineering
conference 2 1986 791-797
[38] IK Garkushin AC Trunin TT Miftakhov and MA Dibirov Salt heat storage
composition USSR Patent 1036734 1983
[39] W M Philips and J W Stears Advanced latent heat of fusion thermal energy storage for
solar power stations In Proceedings of 20th intersociety energy conversion engineering
conference 2 1985 384-391
[40] Y Takahashi M Kamimoto Y Abe R Sakamoto K Kanari and T Ozawa Investigation
of latent heat-thermal energy storage materials IV Thermoanalitical evaluation of binary eutectic
mixtures of NaOH with LiOH or KOH Thermochim Acta 121 1987 193-202
[41] C E Birchenall and A F Riechman Heat storage in eutectic alloys Metall Trans A
11A(8) 1980 1415-1420
100
[42] Y Takahashi R Sakamoto and M Kamimoto Heat capacities and latent heats of LiNO3
NaNO3 and KNO3 International Journal of Thermophysics 9(6) 1988 1081-1090
[43] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate Mixtures
Journal of Chemical Engineering Data 8(3) 1963 469
[44] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical Engineering Data 6 (4) 1961 493
[45] GF Petersen WA Ewing and G P Smith Densities of Some Salt Mixtures Journal of
Chemical Engineering Data 6 (4) 1961 540
[46] G J Janz and M R Lorenz Precise Measurement of Density and Surface Tension at
Temperatures up to 1000degC in One Apparatus Review of Scientific Instruments 31 (1) 1960
18-23
[47] G J Janz C B Allen N P Bansal R M Murphy and R P Tomkins Physical Properties
Data Compilations Relevant to Energy Storage II Molten Salts Data on Single and Multi-
Component Salt Systems National Bureau of Standards NSRDS-NBS 61 Part II April 1979
[48] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation Equations
for Critically Evaluated Density Surface Tension Electrical Conductance and Viscosity Data
Journal of Physical and Chemical Reference Data 17 1988 2
[49] A T Ward and G J Janz Molten Carbonate Electrolytes Electiral Conductance Density
and Surface Tension of Binary and Ternary Eleclrochimica Acta 10 1965 849-857
[50] Y Takahashi R Sakamoto and MKamimoto Heat Capacities and Latent Heat of LiNO3
NaNO3 amp KNO3 International Journal of Thermophysics 9 1998 1081-1090
[51] R W Carling Heat capacities of NaNO3 and KNO3 up to 800 K Thermochimica Acta 60
1983 265-275
[52] Y Takahashi Latent heat measurement by DSC with sapphire as standard material
Thermochim Acta 88(1) 1985 199-204
101
[53] GW Hohne W Hemminger and HJ Flammersheim Differential Scanning Calorimetry
Springer-Verlag Berlin 1996
[54] W Hemminger and G Hohne Calorimetry Fundamentals and Practice Verlag Weinheim
1984
[55] M Merzlyakov and C Schick Thermal conductivity from dynamic response of DSC
Thermochimica Acta 377 2001 183-191
[56] T Kousksou A Jamil S Gibout and Y Zeraouli Thermal analysis of phase change
emulsion Journal of Thermal Analysis and Calorimetry 96 2009 841-852
[57] A Jamil T Kousksou K El Omari Y Zeraouli and Y Le Guer Heat transfer in salt
solutions enclosed in DSC cells Thermochimica Acta 507-508 2010 15-20
[58] MJ Richardson Quantitative aspects of differential scanning calorimetry Thermochimica
Acta 300 1997 15-28
[59] S Rudtsch Uncertainty of heat capacity measurements with differential scanning
calorimeters Thermochimica Acta 382 2002 17-25
[60] M J Maeso and J Largo The phase diagram of LiNO3-NaNO3 and LiNO3-KNO3 the
behavior of liquid mixtures Thermochimica Acta 223 (1993) 145-156
[61] O J Kleppa A new twin high-temperature reaction calorimeter The heats of mixing in
liquid sodium-potassium nitrates Journal of Physical Chemistry 64(12) (1960) 1937-1940
[62] G W H Hhne H K Cammenga W Eysel E Gmelin and W Hemminger The
Temperature Calibration of Scanning Calorimeters Thermochimica Acta 160 1990 1-12
[63] L B Pankratz Thermodynamic Properties of Carbides Nitrides and Other Selected
Substances U S Bureau of Mines Bulletin 696 1994
[64] M Zhang and R G Reddy Thermodynamic properties of C4mim[Tf2N] ionic liquids 0 2
2010 71-76
102
[65] D Mantha T Wang and R G Reddy Thermodynamic Modeling of Eutectic Point in the
LiNO3-NaNO3-KNO3 Ternary System Journal of Phase Equilibria and Diffusion 2011
(accepted)
[66] R G Reddy T Wang and D Mantha Determination of thermodynamic properties of
2KNO3Mg(NO3)2 Thermochimica Acta 2011 (submitted)
[67] T Wang D Mantha and R G Reddy Thermal stability of new LiNO3-NaNO3-KNO3
ternary salt for thermal energy storage system (in preparation)
[68] G D Carvalho E Frollini and W N D Santos Thermal conductivity of polymers by hot-
wire method J Appl Poly Sci 62 (1996) 2281-2285
[69] H Bloom A Doroszkowski and S B Tricklebank Molten salt mixtures IX The thermal
conductivities of molten nitrate systems Aus J Chem 18(8) (1965) 1171-1176
[70] A G Turnbull Thermal conductivity of molten salts Aus J Appl Sci 12 (1961) 30-41
[71] L R White and H T Davis Thermal conductivity of molten alkali nitrates J Chem Phys
47(1967) 5433-5439
[72] M V Peralta-Martinez M J Assael M J Dix L Karagiannidis and W A Wakeham A
Novel Instrument for the Measurement of the Thermal Conductivity of Molten Metal Part1
Instrument‟s Description Int J Thermophysics 27 (2006) 353-375
[73] Y Tada M Harada M Tanlgakl and W Eguchl Laser Flash Method for Measuring
Thermal Conductivity of Liquids Application to Molten Salts Industrial and Engineering
Chemistry Fundamentals 20 1981 333- 336
[74] M V Smirnov V A Khokhlov and E S Filatov Thermal conductivity of molten alkali
halides and their mixtures Electrochimica Acta 32 (1986) 1019-1026
[75] E Marti E Kaisersberger and W D Emmerich NEW ASPECTS OF THERMAL
ANALYSIS Part I Resolution of DSC and means for its optimization Journal of Thermal
Analysis and Calorimetry 77 2004 905-934
103
[76] E Marti E Kaisersberger G Kaiser and WY Ma Netzsch Annual 2000
bdquoThermoanalytical Characterization of Pharmaceuticals‟ Netzsch-Geraumltebau GmbH D-95100
SelbBavaria
[77] P J van Ekeren C M Holl and A J Witteveen A comparative test of differential
scanning calorimeters Journal of Thermal Analysis and Calorimetry 49 1997 1105-1114
[78] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation
Equations for Critically Evaluated Density Surface Tension Electrical Conductance and
Viscosity Data Journal of Physical and Chemical Reference Data 17 1988 1
[79] G F Petersen W A Ewing and G P Smith ldquoDensities of Some Salt Mixturesrdquo Journal of
Chemical and Engineering Data 6 1961 540
[80] P M Nasch and S G Steinemann Density and Thermal Expansion of Molten Manganese
Iron Nickel Copper Aluminum and Tin by Means of the Gamma-Ray Attenuation Technique
Physics and Chemistry of Liquids 29 1995 43-58
[81] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical and Engineering Data 6 1961 493-496
[82] D A Nissen Thermophysical Properties of the Equimolar Mixture NaNO3-KNO3 from
300degC to 600degC Journal of Chemical and Engineering Data 27 1982 269-273
[83] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate
Mixtures Journal of Chemical and Engineering Data 8 1963 469
104
APPENDIX
Appendix A
Table A1 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in solid state
(29815-40315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 342 1290 417 -025
299 027 008 000 343 1317 426 -026
300 059 018 000 344 1345 436 -027
301 091 028 000 345 1372 445 -028
302 123 037 000 346 1399 455 -029
303 154 047 000 347 1427 464 -031
304 186 056 000 348 1454 474 -032
305 217 066 000 349 1481 483 -033
306 248 076 000 350 1508 493 -035
307 279 085 000 351 1535 503 -036
308 310 095 -001 352 1562 512 -038
309 340 104 -001 353 1589 522 -039
310 371 114 -001 354 1616 532 -041
311 401 123 -001 355 1643 541 -042
312 432 133 -002 356 1670 551 -044
313 462 142 -002 357 1697 561 -045
314 492 152 -002 358 1724 570 -047
315 521 161 -003 359 1751 580 -048
316 551 171 -003 360 1777 590 -050
317 581 180 -004 361 1804 600 -052
318 610 190 -004 362 1831 610 -053
319 640 199 -005 363 1858 619 -055
320 669 209 -005 364 1885 629 -057
105
321 698 218 -006 365 1911 639 -059
322 727 228 -007 366 1938 649 -060
323 756 237 -007 367 1965 659 -062
324 785 246 -008 368 1992 669 -064
325 814 256 -009 369 2018 679 -066
326 842 265 -009 370 2045 689 -068
327 871 275 -010 371 2072 699 -070
328 899 284 -011 372 2098 709 -072
329 928 294 -012 373 2125 719 -074
330 956 303 -012 374 2152 729 -076
331 984 313 -013 375 2179 739 -078
332 1012 322 -014 376 2205 750 -080
333 1041 331 -015 377 2232 760 -082
334 1069 341 -016 378 2259 770 -084
335 1096 350 -017 379 2286 780 -086
336 1124 360 -018 380 2312 791 -088
337 1152 369 -019 381 2339 801 -090
338 1180 379 -020 382 2366 811 -093
339 1207 388 -021 383 2393 822 -095
340 1235 398 -022 384 2420 832 -097
341 1263 407 -023 38415 2424 834 -097
Table A2 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in liquid state
(40315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
40315 4287 1565 -163 514 7070 2838 -796
404 4310 1575 -167 515 7094 2850 -803
405 4337 1585 -171 516 7117 2863 -810
406 4363 1596 -175 517 7141 2875 -817
407 4390 1607 -180 518 7165 2887 -824
408 4417 1618 -184 519 7188 2899 -831
409 4443 1629 -189 520 7212 2911 -839
410 4470 1640 -193 521 7235 2924 -846
411 4496 1651 -197 522 7259 2936 -853
412 4523 1662 -202 523 7282 2948 -860
106
413 4549 1672 -206 524 7306 2960 -868
414 4576 1683 -211 525 7329 2973 -875
415 4602 1694 -216 526 7352 2985 -882
416 4629 1705 -220 527 7376 2997 -890
417 4655 1716 -225 528 7399 3010 -897
418 4681 1727 -230 529 7422 3022 -904
419 4708 1738 -234 530 7446 3034 -912
420 4734 1749 -239 531 7469 3047 -919
421 4760 1760 -244 532 7492 3059 -927
422 4786 1771 -249 533 7516 3071 -934
423 4813 1782 -253 534 7539 3084 -942
424 4839 1793 -258 535 7562 3096 -949
425 4865 1804 -263 536 7585 3109 -957
426 4891 1816 -268 537 7608 3121 -965
427 4917 1827 -273 538 7632 3134 -972
428 4943 1838 -278 539 7655 3146 -980
429 4969 1849 -283 540 7678 3158 -988
430 4995 1860 -288 541 7701 3171 -995
431 5021 1871 -293 542 7724 3183 -1003
432 5046 1882 -298 543 7747 3196 -1011
433 5072 1894 -303 544 7770 3208 -1018
434 5098 1905 -308 545 7793 3221 -1026
435 5124 1916 -313 546 7816 3233 -1034
436 5149 1927 -318 547 7839 3246 -1042
437 5175 1938 -323 548 7862 3259 -1050
438 5201 1950 -328 549 7885 3271 -1058
439 5226 1961 -334 550 7908 3284 -1066
440 5252 1972 -339 551 7931 3296 -1073
441 5278 1983 -344 552 7953 3309 -1081
442 5303 1995 -349 553 7976 3322 -1089
443 5329 2006 -355 554 7999 3334 -1097
444 5354 2017 -360 555 8022 3347 -1105
445 5380 2028 -365 556 8045 3359 -1113
446 5405 2040 -371 557 8067 3372 -1121
447 5430 2051 -376 558 8090 3385 -1130
448 5456 2062 -382 559 8113 3398 -1138
449 5481 2074 -387 560 8136 3410 -1146
450 5506 2085 -393 561 8158 3423 -1154
451 5532 2097 -398 562 8181 3436 -1162
452 5557 2108 -404 563 8204 3448 -1170
107
453 5582 2119 -409 564 8226 3461 -1178
454 5607 2131 -415 565 8249 3474 -1187
455 5633 2142 -421 566 8271 3487 -1195
456 5658 2154 -426 567 8294 3499 -1203
457 5683 2165 -432 568 8317 3512 -1212
458 5708 2177 -438 569 8339 3525 -1220
459 5733 2188 -443 570 8362 3538 -1228
460 5758 2200 -449 571 8384 3551 -1237
461 5783 2211 -455 572 8407 3564 -1245
462 5808 2223 -461 573 8429 3576 -1253
463 5833 2234 -466 574 8452 3589 -1262
464 5858 2246 -472 575 8474 3602 -1270
465 5883 2257 -478 576 8496 3615 -1279
466 5907 2269 -484 577 8519 3628 -1287
467 5932 2280 -490 578 8541 3641 -1296
468 5957 2292 -496 579 8564 3654 -1304
469 5982 2304 -502 580 8586 3667 -1313
470 6007 2315 -508 581 8608 3680 -1322
471 6031 2327 -514 582 8631 3693 -1330
472 6056 2339 -520 583 8653 3706 -1339
473 6081 2350 -526 584 8675 3719 -1348
474 6105 2362 -532 585 8697 3732 -1356
475 6130 2373 -538 586 8720 3745 -1365
476 6155 2385 -544 587 8742 3758 -1374
477 6179 2397 -551 588 8764 3771 -1382
478 6204 2409 -557 589 8786 3784 -1391
479 6228 2420 -563 590 8808 3797 -1400
480 6253 2432 -569 591 8831 3810 -1409
481 6277 2444 -575 592 8853 3823 -1418
482 6301 2456 -582 593 8875 3836 -1426
483 6326 2467 -588 594 8897 3849 -1435
484 6350 2479 -594 595 8919 3863 -1444
485 6375 2491 -601 596 8941 3876 -1453
486 6399 2503 -607 597 8963 3889 -1462
487 6423 2515 -614 598 8985 3902 -1471
488 6448 2526 -620 599 9007 3915 -1480
489 6472 2538 -626 600 9029 3928 -1489
490 6496 2550 -633 601 9051 3942 -1498
491 6520 2562 -639 602 9073 3955 -1507
492 6544 2574 -646 603 9095 3968 -1516
108
493 6569 2586 -653 604 9117 3981 -1525
494 6593 2598 -659 605 9139 3994 -1535
495 6617 2610 -666 606 9161 4008 -1544
496 6641 2621 -672 607 9183 4021 -1553
497 6665 2633 -679 608 9205 4034 -1562
498 6689 2645 -686 609 9226 4048 -1571
499 6713 2657 -692 610 9248 4061 -1581
500 6737 2669 -699 611 9270 4074 -1590
501 6761 2681 -706 612 9292 4088 -1599
502 6785 2693 -713 613 9314 4101 -1608
503 6809 2705 -719 614 9335 4114 -1618
504 6833 2717 -726 615 9357 4128 -1627
505 6856 2729 -733 616 9379 4141 -1636
506 6880 2741 -740 617 9401 4154 -1646
507 6904 2754 -747 618 9422 4168 -1655
508 6928 2766 -754 619 9444 4181 -1665
509 6952 2778 -761 620 9466 4195 -1674
510 6975 2790 -768 621 9487 4208 -1684
511 6999 2802 -775 622 9509 4222 -1693
512 7023 2814 -782 623 9531 4235 -1703
513 7047 2826 -789 62315 9534 4237 -1704
109
Appendix B
Table B1 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(29815-39215K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 347 1233 382 -046
299 022 006 000 348 1258 390 -048
300 049 014 -001 349 1283 398 -049
301 075 022 -001 350 1307 406 -051
302 101 029 -001 351 1332 415 -053
303 127 037 -002 352 1356 423 -054
304 153 044 -002 353 1381 431 -056
305 179 052 -003 354 1405 440 -058
306 205 059 -003 355 1430 448 -060
307 230 067 -004 356 1455 456 -061
308 256 075 -004 357 1479 465 -063
309 282 082 -005 358 1504 473 -065
310 308 090 -005 359 1528 482 -067
311 333 098 -006 360 1553 490 -069
312 359 105 -007 361 1577 498 -071
313 384 113 -007 362 1602 507 -073
314 410 121 -008 363 1626 515 -075
315 435 128 -009 364 1651 524 -077
316 461 136 -010 365 1675 533 -079
317 486 144 -010 366 1700 541 -081
318 511 151 -011 367 1724 550 -083
319 537 159 -012 368 1749 558 -085
320 562 167 -013 369 1773 567 -087
321 587 175 -014 370 1798 576 -089
322 612 182 -015 371 1822 584 -092
323 637 190 -016 372 1847 593 -094
324 663 198 -017 373 1871 602 -096
325 688 206 -018 374 1896 611 -098
326 713 214 -019 375 1920 620 -100
327 738 222 -020 376 1945 628 -103
328 763 229 -021 377 1969 637 -105
329 788 237 -022 378 1994 646 -107
110
330 813 245 -023 379 2018 655 -110
331 838 253 -024 380 2043 664 -112
332 863 261 -025 381 2068 673 -115
333 887 269 -027 382 2092 682 -117
334 912 277 -028 383 2117 691 -120
335 937 285 -029 384 2141 700 -122
336 962 293 -030 385 2166 709 -125
337 987 301 -032 386 2191 718 -127
338 1011 309 -033 387 2215 727 -130
339 1036 317 -034 388 2240 737 -132
340 1061 325 -036 389 2265 746 -135
341 1086 333 -037 390 2289 755 -138
342 1110 341 -039 391 2314 764 -140
343 1135 349 -040 392 2339 774 -143
344 1160 357 -042 39215 2342 775 -144
345 1184 365 -043
Table B2 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(41315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
414 3280 1149 -209 520 5608 2235 -682
415 3302 1158 -212 521 5630 2246 -687
416 3325 1167 -216 522 5651 2257 -693
417 3348 1177 -219 523 5672 2268 -698
418 3370 1186 -223 524 5694 2279 -704
419 3393 1196 -226 525 5715 2290 -710
420 3416 1205 -229 526 5736 2302 -716
421 3438 1215 -233 527 5757 2313 -721
422 3461 1224 -236 528 5779 2324 -727
423 3483 1234 -240 529 5800 2335 -733
424 3506 1243 -243 530 5821 2347 -739
425 3529 1253 -247 531 5842 2358 -745
426 3551 1263 -250 532 5864 2369 -750
427 3574 1272 -254 533 5885 2380 -756
428 3596 1282 -257 534 5906 2392 -762
429 3619 1291 -261 535 5927 2403 -768
111
430 3641 1301 -265 536 5948 2414 -774
431 3663 1311 -268 537 5970 2426 -780
432 3686 1320 -272 538 5991 2437 -786
433 3708 1330 -276 539 6012 2449 -792
434 3731 1340 -279 540 6033 2460 -798
435 3753 1350 -283 541 6054 2471 -804
436 3775 1359 -287 542 6075 2483 -810
437 3798 1369 -291 543 6096 2494 -816
438 3820 1379 -294 544 6118 2506 -822
439 3842 1389 -298 545 6139 2517 -828
440 3865 1398 -302 546 6160 2529 -835
441 3887 1408 -306 547 6181 2540 -841
442 3909 1418 -310 548 6202 2552 -847
443 3932 1428 -314 549 6223 2563 -853
444 3954 1438 -318 550 6244 2575 -859
445 3976 1448 -322 551 6265 2586 -866
446 3998 1458 -326 552 6286 2598 -872
447 4021 1468 -330 553 6307 2610 -878
448 4043 1477 -334 554 6328 2621 -884
449 4065 1487 -338 555 6349 2633 -891
450 4087 1497 -342 556 6370 2645 -897
451 4109 1507 -346 557 6391 2656 -904
452 4131 1517 -350 558 6412 2668 -910
453 4154 1527 -354 559 6433 2680 -916
454 4176 1537 -358 560 6454 2691 -923
455 4198 1547 -363 561 6475 2703 -929
456 4220 1557 -367 562 6496 2715 -936
457 4242 1568 -371 563 6517 2727 -942
458 4264 1578 -375 564 6538 2738 -949
459 4286 1588 -380 565 6559 2750 -955
460 4308 1598 -384 566 6580 2762 -962
461 4330 1608 -388 567 6600 2774 -969
462 4352 1618 -393 568 6621 2786 -975
463 4374 1628 -397 569 6642 2798 -982
464 4396 1639 -401 570 6663 2810 -988
465 4418 1649 -406 571 6684 2821 -995
466 4440 1659 -410 572 6705 2833 -1002
467 4462 1669 -415 573 6726 2845 -1009
468 4484 1680 -419 574 6747 2857 -1015
469 4506 1690 -424 575 6767 2869 -1022
112
470 4528 1700 -428 576 6788 2881 -1029
471 4550 1710 -433 577 6809 2893 -1036
472 4572 1721 -437 578 6830 2905 -1042
473 4593 1731 -442 579 6851 2917 -1049
474 4615 1741 -446 580 6871 2929 -1056
475 4637 1752 -451 581 6892 2941 -1063
476 4659 1762 -456 582 6913 2953 -1070
477 4681 1773 -460 583 6934 2966 -1077
478 4703 1783 -465 584 6954 2978 -1084
479 4724 1793 -470 585 6975 2990 -1091
480 4746 1804 -474 586 6996 3002 -1098
481 4768 1814 -479 587 7017 3014 -1105
482 4790 1825 -484 588 7037 3026 -1112
483 4812 1835 -489 589 7058 3038 -1119
484 4833 1846 -494 590 7079 3051 -1126
485 4855 1856 -498 591 7100 3063 -1133
486 4877 1867 -503 592 7120 3075 -1140
487 4898 1877 -508 593 7141 3087 -1147
488 4920 1888 -513 594 7162 3100 -1154
489 4942 1899 -518 595 7182 3112 -1162
490 4963 1909 -523 596 7203 3124 -1169
491 4985 1920 -528 597 7224 3137 -1176
492 5007 1930 -533 598 7244 3149 -1183
493 5028 1941 -538 599 7265 3161 -1190
494 5050 1952 -543 600 7285 3174 -1198
495 5072 1962 -548 601 7306 3186 -1205
496 5093 1973 -553 602 7327 3198 -1212
497 5115 1984 -558 603 7347 3211 -1220
498 5136 1995 -563 604 7368 3223 -1227
499 5158 2005 -568 605 7389 3236 -1234
500 5180 2016 -574 606 7409 3248 -1242
501 5201 2027 -579 607 7430 3261 -1249
502 5223 2038 -584 608 7450 3273 -1257
503 5244 2049 -589 609 7471 3286 -1264
504 5266 2059 -595 610 7491 3298 -1272
505 5287 2070 -600 611 7512 3311 -1279
506 5309 2081 -605 612 7532 3323 -1287
507 5330 2092 -610 613 7553 3336 -1294
508 5352 2103 -616 614 7573 3348 -1302
509 5373 2114 -621 615 7594 3361 -1309
113
510 5394 2125 -627 616 7615 3374 -1317
511 5416 2136 -632 617 7635 3386 -1325
512 5437 2147 -637 618 7656 3399 -1332
513 5459 2158 -643 619 7676 3412 -1340
514 5480 2169 -648 620 7696 3424 -1348
515 5502 2180 -654 621 7717 3437 -1355
516 5523 2191 -659 622 7737 3450 -1363
517 5544 2202 -665 623 7758 3462 -1371
518 5566 2213 -670 62315 7761 3464 -1372
114
Appendix C
Table C1 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in solid
state (29815-36415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 333 1937 611 -034
299 048 014 000 334 1992 629 -036
300 104 031 000 335 2047 647 -038
301 160 048 000 336 2102 666 -040
302 216 065 000 337 2156 684 -042
303 272 082 -001 338 2211 703 -045
304 329 099 -001 339 2266 721 -047
305 385 116 -001 340 2321 740 -049
306 441 133 -002 341 2375 758 -052
307 496 150 -002 342 2430 777 -054
308 552 167 -003 343 2485 796 -056
309 608 185 -003 344 2539 815 -059
310 664 202 -004 345 2594 833 -062
311 720 219 -005 346 2648 852 -064
312 776 236 -006 347 2703 871 -067
313 831 254 -006 348 2757 890 -070
314 887 271 -007 349 2812 909 -072
315 942 289 -008 350 2866 928 -075
316 998 306 -009 351 2921 947 -078
317 1054 324 -010 352 2975 966 -081
318 1109 341 -011 353 3029 985 -084
319 1164 359 -012 354 3084 1004 -087
320 1220 377 -014 355 3138 1024 -090
321 1275 395 -015 356 3192 1043 -094
322 1331 412 -016 357 3246 1062 -097
323 1386 430 -018 358 3300 1082 -100
324 1441 448 -019 359 3355 1101 -103
325 1496 466 -020 360 3409 1120 -107
326 1552 484 -022 361 3463 1140 -110
327 1607 502 -024 362 3517 1159 -114
328 1662 520 -025 363 3571 1179 -117
329 1717 538 -027 364 3625 1199 -121
115
330 1772 556 -029 36415 3633 1202 -121
331 1827 574 -030
332 1882 593 -032
Table C2 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in liquid
state (42115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
42115 7428 2673 -455 523 11788 4725 -1440
422 7468 2690 -461 524 11827 4745 -1452
423 7515 2710 -468 525 11866 4766 -1464
424 7562 2730 -476 526 11904 4786 -1476
425 7608 2750 -484 527 11943 4807 -1488
426 7655 2770 -491 528 11982 4827 -1500
427 7702 2790 -499 529 12021 4847 -1512
428 7748 2810 -507 530 12059 4868 -1524
429 7795 2830 -514 531 12098 4888 -1536
430 7841 2849 -522 532 12137 4909 -1548
431 7887 2869 -530 533 12175 4929 -1560
432 7933 2889 -538 534 12213 4950 -1572
433 7979 2909 -546 535 12252 4970 -1584
434 8025 2929 -554 536 12290 4991 -1597
435 8071 2949 -562 537 12328 5011 -1609
436 8117 2969 -570 538 12366 5032 -1621
437 8163 2989 -578 539 12404 5052 -1634
438 8208 3009 -586 540 12442 5073 -1646
439 8254 3029 -595 541 12480 5093 -1659
440 8299 3049 -603 542 12518 5114 -1671
441 8345 3069 -611 543 12556 5134 -1684
442 8390 3089 -620 544 12594 5155 -1696
443 8435 3109 -628 545 12632 5175 -1709
444 8480 3129 -636 546 12669 5196 -1721
445 8525 3149 -645 547 12707 5217 -1734
446 8570 3169 -654 548 12745 5237 -1747
116
447 8615 3189 -662 549 12782 5258 -1760
448 8659 3209 -671 550 12820 5278 -1772
449 8704 3229 -679 551 12857 5299 -1785
450 8748 3249 -688 552 12894 5319 -1798
451 8793 3269 -697 553 12932 5340 -1811
452 8837 3289 -706 554 12969 5361 -1824
453 8881 3309 -715 555 13006 5381 -1837
454 8926 3329 -724 556 13043 5402 -1850
455 8970 3349 -732 557 13080 5422 -1863
456 9014 3369 -741 558 13117 5443 -1876
457 9058 3389 -750 559 13154 5464 -1889
458 9102 3409 -760 560 13191 5484 -1902
459 9145 3429 -769 561 13228 5505 -1916
460 9189 3449 -778 562 13264 5526 -1929
461 9233 3469 -787 563 13301 5546 -1942
462 9276 3489 -796 564 13338 5567 -1956
463 9319 3509 -806 565 13374 5588 -1969
464 9363 3529 -815 566 13411 5608 -1982
465 9406 3549 -824 567 13447 5629 -1996
466 9449 3570 -834 568 13484 5650 -2009
467 9492 3590 -843 569 13520 5670 -2023
468 9535 3610 -853 570 13557 5691 -2036
469 9578 3630 -862 571 13593 5712 -2050
470 9621 3650 -872 572 13629 5732 -2063
471 9664 3670 -882 573 13665 5753 -2077
472 9707 3690 -891 574 13701 5774 -2091
473 9749 3710 -901 575 13737 5795 -2104
474 9792 3731 -911 576 13773 5815 -2118
475 9834 3751 -921 577 13809 5836 -2132
476 9877 3771 -930 578 13845 5857 -2146
477 9919 3791 -940 579 13881 5877 -2160
478 9961 3811 -950 580 13917 5898 -2174
479 10004 3831 -960 581 13953 5919 -2188
480 10046 3852 -970 582 13988 5940 -2202
481 10088 3872 -980 583 14024 5960 -2216
482 10130 3892 -990 584 14060 5981 -2230
483 10171 3912 -1001 585 14095 6002 -2244
484 10213 3932 -1011 586 14131 6023 -2258
485 10255 3953 -1021 587 14166 6044 -2272
486 10297 3973 -1031 588 14201 6064 -2286
117
487 10338 3993 -1042 589 14237 6085 -2300
488 10380 4013 -1052 590 14272 6106 -2315
489 10421 4034 -1062 591 14307 6127 -2329
490 10462 4054 -1073 592 14342 6148 -2343
491 10504 4074 -1083 593 14378 6168 -2358
492 10545 4094 -1094 594 14413 6189 -2372
493 10586 4114 -1104 595 14448 6210 -2386
494 10627 4135 -1115 596 14483 6231 -2401
495 10668 4155 -1126 597 14518 6252 -2415
496 10709 4175 -1136 598 14552 6273 -2430
497 10750 4196 -1147 599 14587 6293 -2444
498 10791 4216 -1158 600 14622 6314 -2459
499 10831 4236 -1169 601 14657 6335 -2474
500 10872 4256 -1179 602 14692 6356 -2488
501 10912 4277 -1190 603 14726 6377 -2503
502 10953 4297 -1201 604 14761 6398 -2518
503 10993 4317 -1212 605 14795 6419 -2533
504 11034 4338 -1223 606 14830 6439 -2547
505 11074 4358 -1234 607 14864 6460 -2562
506 11114 4378 -1245 608 14899 6481 -2577
507 11154 4399 -1257 609 14933 6502 -2592
508 11194 4419 -1268 610 14967 6523 -2607
509 11234 4439 -1279 611 15002 6544 -2622
510 11274 4460 -1290 612 15036 6565 -2637
511 11314 4480 -1302 613 15070 6586 -2652
512 11354 4500 -1313 614 15104 6607 -2667
513 11394 4521 -1324 615 15138 6628 -2682
514 11433 4541 -1336 616 15172 6649 -2697
515 11473 4562 -1347 617 15206 6670 -2713
516 11513 4582 -1359 618 15240 6691 -2728
517 11552 4602 -1370 619 15274 6712 -2743
518 11591 4623 -1382 620 15308 6733 -2758
519 11631 4643 -1393 621 15342 6754 -2774
520 11670 4664 -1405 622 15375 6774 -2789
521 11709 4684 -1417 623 15409 6795 -2804
522 11748 4704 -1428 62315 15414 6799 -2807
118
Appendix D
Table D1 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in solid state
(29815-36315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
299 021 006 000 333 867 277 -012
300 047 014 000 334 891 285 -012
301 072 022 000 335 916 293 -013
302 097 029 000 336 940 302 -014
303 122 037 000 337 964 310 -015
304 147 045 000 338 989 318 -016
305 172 053 000 339 1013 327 -017
306 197 060 000 340 1037 335 -018
307 223 068 000 341 1061 343 -019
308 248 076 000 342 1085 352 -019
309 273 084 000 343 1109 360 -020
310 298 092 -001 344 1134 369 -021
311 323 099 -001 345 1158 377 -022
312 348 107 -001 346 1182 385 -024
313 373 115 -001 347 1206 394 -025
314 398 123 -002 348 1230 402 -026
315 423 131 -002 349 1254 411 -027
316 447 139 -002 350 1277 419 -028
317 472 147 -003 351 1301 428 -029
318 497 155 -003 352 1325 436 -030
319 522 163 -003 353 1349 445 -032
320 547 171 -004 354 1373 453 -033
321 572 179 -004 355 1396 462 -034
322 596 187 -005 356 1420 470 -035
323 621 195 -005 357 1444 479 -037
324 646 203 -006 358 1467 487 -038
325 670 211 -006 359 1491 496 -039
326 695 220 -007 360 1514 504 -041
327 720 228 -008 361 1538 513 -042
328 744 236 -008 362 1561 522 -043
329 769 244 -009 363 1584 530 -045
330 793 252 -010 36315 1588 532 -045
119
331 818 260 -010
Table D2 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in liquid
state (38115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
38115 2281 765 -104 503 5639 2242 -594
382 2307 775 -106 504 5664 2255 -600
383 2338 787 -109 505 5689 2267 -606
384 2369 798 -111 506 5713 2280 -611
385 2399 810 -113 507 5738 2292 -617
386 2430 822 -116 508 5763 2305 -623
387 2460 834 -118 509 5787 2317 -629
388 2491 846 -121 510 5812 2330 -634
389 2521 857 -123 511 5836 2342 -640
390 2551 869 -126 512 5861 2355 -646
391 2582 881 -128 513 5885 2367 -652
392 2612 893 -131 514 5910 2380 -658
393 2642 905 -134 515 5934 2392 -664
394 2672 917 -136 516 5959 2405 -670
395 2702 928 -139 517 5983 2417 -676
396 2732 940 -142 518 6007 2430 -682
397 2762 952 -144 519 6032 2443 -688
398 2792 964 -147 520 6056 2455 -694
399 2821 976 -150 521 6080 2468 -700
400 2851 988 -153 522 6104 2480 -706
401 2881 999 -156 523 6128 2493 -712
402 2910 1011 -159 524 6152 2506 -718
403 2940 1023 -162 525 6176 2518 -724
404 2969 1035 -164 526 6200 2531 -731
405 2999 1047 -167 527 6224 2544 -737
406 3028 1059 -170 528 6248 2556 -743
407 3057 1071 -174 529 6272 2569 -749
408 3087 1083 -177 530 6296 2581 -756
120
409 3116 1095 -180 531 6320 2594 -762
410 3145 1107 -183 532 6344 2607 -768
411 3174 1119 -186 533 6368 2619 -775
412 3203 1130 -189 534 6391 2632 -781
413 3232 1142 -192 535 6415 2645 -787
414 3261 1154 -196 536 6439 2657 -794
415 3290 1166 -199 537 6462 2670 -800
416 3319 1178 -202 538 6486 2683 -807
417 3347 1190 -206 539 6510 2696 -813
418 3376 1202 -209 540 6533 2708 -820
419 3405 1214 -212 541 6557 2721 -826
420 3433 1226 -216 542 6580 2734 -833
421 3462 1238 -219 543 6604 2746 -839
422 3490 1250 -223 544 6627 2759 -846
423 3519 1262 -226 545 6650 2772 -853
424 3547 1274 -230 546 6674 2785 -859
425 3575 1286 -233 547 6697 2797 -866
426 3604 1298 -237 548 6720 2810 -873
427 3632 1310 -240 549 6744 2823 -879
428 3660 1322 -244 550 6767 2836 -886
429 3688 1334 -248 551 6790 2848 -893
430 3716 1346 -251 552 6813 2861 -900
431 3744 1358 -255 553 6836 2874 -907
432 3772 1371 -259 554 6860 2887 -913
433 3800 1383 -263 555 6883 2900 -920
434 3828 1395 -267 556 6906 2912 -927
435 3856 1407 -270 557 6929 2925 -934
436 3883 1419 -274 558 6952 2938 -941
437 3911 1431 -278 559 6975 2951 -948
438 3939 1443 -282 560 6998 2964 -955
439 3966 1455 -286 561 7020 2976 -962
440 3994 1467 -290 562 7043 2989 -969
441 4021 1479 -294 563 7066 3002 -976
442 4049 1491 -298 564 7089 3015 -983
443 4076 1504 -302 565 7112 3028 -990
444 4103 1516 -306 566 7134 3041 -997
445 4131 1528 -310 567 7157 3054 -1005
446 4158 1540 -314 568 7180 3066 -1012
447 4185 1552 -319 569 7203 3079 -1019
448 4212 1564 -323 570 7225 3092 -1026
121
449 4240 1576 -327 571 7248 3105 -1033
450 4267 1589 -331 572 7270 3118 -1041
451 4294 1601 -336 573 7293 3131 -1048
452 4321 1613 -340 574 7315 3144 -1055
453 4347 1625 -344 575 7338 3157 -1063
454 4374 1637 -349 576 7360 3170 -1070
455 4401 1650 -353 577 7383 3183 -1077
456 4428 1662 -357 578 7405 3196 -1085
457 4455 1674 -362 579 7428 3208 -1092
458 4481 1686 -366 580 7450 3221 -1100
459 4508 1698 -371 581 7472 3234 -1107
460 4535 1711 -375 582 7494 3247 -1114
461 4561 1723 -380 583 7517 3260 -1122
462 4588 1735 -384 584 7539 3273 -1129
463 4614 1747 -389 585 7561 3286 -1137
464 4641 1760 -394 586 7583 3299 -1145
465 4667 1772 -398 587 7605 3312 -1152
466 4693 1784 -403 588 7628 3325 -1160
467 4720 1796 -408 589 7650 3338 -1167
468 4746 1809 -412 590 7672 3351 -1175
469 4772 1821 -417 591 7694 3364 -1183
470 4798 1833 -422 592 7716 3377 -1191
471 4825 1846 -427 593 7738 3390 -1198
472 4851 1858 -432 594 7760 3403 -1206
473 4877 1870 -437 595 7782 3416 -1214
474 4903 1882 -441 596 7804 3429 -1222
475 4929 1895 -446 597 7825 3442 -1229
476 4955 1907 -451 598 7847 3455 -1237
477 4980 1919 -456 599 7869 3469 -1245
478 5006 1932 -461 600 7891 3482 -1253
479 5032 1944 -466 601 7913 3495 -1261
480 5058 1956 -471 602 7934 3508 -1269
481 5083 1969 -476 603 7956 3521 -1277
482 5109 1981 -481 604 7978 3534 -1285
483 5135 1994 -487 605 8000 3547 -1293
484 5160 2006 -492 606 8021 3560 -1301
485 5186 2018 -497 607 8043 3573 -1309
486 5211 2031 -502 608 8064 3586 -1317
487 5237 2043 -507 609 8086 3599 -1325
488 5262 2055 -513 610 8107 3613 -1333
122
489 5288 2068 -518 611 8129 3626 -1341
490 5313 2080 -523 612 8150 3639 -1349
491 5338 2093 -528 613 8172 3652 -1357
492 5364 2105 -534 614 8193 3665 -1366
493 5389 2117 -539 615 8215 3678 -1374
494 5414 2130 -545 616 8236 3692 -1382
495 5439 2142 -550 617 8258 3705 -1390
496 5464 2155 -555 618 8279 3718 -1398
497 5489 2167 -561 619 8300 3731 -1407
498 5514 2180 -566 620 8321 3744 -1415
499 5539 2192 -572 621 8343 3757 -1423
500 5564 2205 -578 622 8364 3771 -1432
501 5589 2217 -583 623 8385 3784 -1441
502 5614 2230 -589 62315 8388 3786 -1443
123
Appendix E
Table E1 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in solid state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 913 287 -014
299 025 007 000 331 941 296 -015
300 054 016 000 332 970 306 -016
301 083 025 000 333 998 315 -017
302 112 034 000 334 1026 324 -018
303 141 042 000 335 1054 334 -019
304 170 051 000 336 1081 343 -020
305 199 060 -001 337 1109 353 -021
306 228 069 -001 338 1137 362 -022
307 257 078 -001 339 1165 371 -024
308 286 087 -001 340 1193 381 -025
309 315 096 -002 341 1221 390 -026
310 343 105 -002 342 1248 400 -027
311 372 113 -002 343 1276 409 -028
312 401 122 -003 344 1304 419 -030
313 430 131 -003 345 1331 428 -031
314 458 140 -003 346 1359 438 -032
315 487 149 -004 347 1386 447 -034
316 516 159 -004 348 1414 457 -035
317 544 168 -005 349 1441 466 -036
318 573 177 -006 350 1468 476 -038
319 602 186 -006 351 1496 486 -039
320 630 195 -007 352 1523 495 -041
321 659 204 -007 353 1550 505 -042
322 687 213 -008 354 1577 514 -044
323 715 222 -009 355 1605 524 -046
324 744 232 -009 356 1632 534 -047
325 772 241 -010 357 1659 543 -049
326 800 250 -011 358 1686 553 -050
327 829 259 -012 359 1713 563 -052
328 857 269 -013 35915 1717 564 -052
329 885 278 -013
124
Table E2 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in liquid state (376-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2323 777 -094 500 5525 2173 -590
376 2347 786 -096 501 5548 2184 -595
377 2375 797 -098 502 5572 2196 -601
378 2403 808 -101 503 5595 2208 -606
379 2431 818 -103 504 5619 2220 -612
380 2459 829 -106 505 5642 2232 -618
381 2487 839 -108 506 5665 2243 -623
382 2515 850 -111 507 5689 2255 -629
383 2542 861 -113 508 5712 2267 -635
384 2570 871 -116 509 5735 2279 -640
385 2598 882 -118 510 5759 2291 -646
386 2626 893 -121 511 5782 2303 -652
387 2653 903 -123 512 5805 2315 -658
388 2681 914 -126 513 5828 2326 -664
389 2708 925 -129 514 5852 2338 -669
390 2736 935 -132 515 5875 2350 -675
391 2763 946 -134 516 5898 2362 -681
392 2791 957 -137 517 5921 2374 -687
393 2818 968 -140 518 5944 2386 -693
394 2845 978 -143 519 5967 2398 -699
395 2873 989 -146 520 5990 2410 -705
396 2900 1000 -148 521 6013 2422 -711
397 2927 1011 -151 522 6036 2434 -717
398 2954 1022 -154 523 6059 2446 -723
399 2981 1032 -157 524 6082 2458 -729
400 3008 1043 -160 525 6105 2470 -735
401 3035 1054 -163 526 6128 2482 -741
402 3062 1065 -166 527 6151 2494 -747
403 3089 1076 -169 528 6173 2506 -754
404 3116 1086 -172 529 6196 2518 -760
405 3143 1097 -176 530 6219 2530 -766
125
406 3170 1108 -179 531 6242 2542 -772
407 3197 1119 -182 532 6265 2554 -778
408 3223 1130 -185 533 6287 2566 -785
409 3250 1141 -188 534 6310 2578 -791
410 3277 1152 -192 535 6333 2591 -797
411 3303 1163 -195 536 6355 2603 -804
412 3330 1174 -198 537 6378 2615 -810
413 3356 1185 -202 538 6400 2627 -816
414 3383 1195 -205 539 6423 2639 -823
415 3409 1206 -208 540 6445 2651 -829
416 3436 1217 -212 541 6468 2663 -836
417 3462 1228 -215 542 6490 2676 -842
418 3488 1239 -219 543 6513 2688 -849
419 3515 1250 -222 544 6535 2700 -855
420 3541 1261 -226 545 6558 2712 -862
421 3567 1272 -229 546 6580 2724 -868
422 3593 1283 -233 547 6602 2737 -875
423 3619 1294 -236 548 6625 2749 -882
424 3645 1305 -240 549 6647 2761 -888
425 3671 1317 -244 550 6669 2773 -895
426 3697 1328 -247 551 6692 2786 -902
427 3723 1339 -251 552 6714 2798 -908
428 3749 1350 -255 553 6736 2810 -915
429 3775 1361 -259 554 6758 2822 -922
430 3801 1372 -262 555 6780 2835 -929
431 3827 1383 -266 556 6803 2847 -935
432 3852 1394 -270 557 6825 2859 -942
433 3878 1405 -274 558 6847 2872 -949
434 3904 1416 -278 559 6869 2884 -956
435 3929 1428 -282 560 6891 2896 -963
436 3955 1439 -286 561 6913 2909 -970
437 3981 1450 -290 562 6935 2921 -977
438 4006 1461 -294 563 6957 2933 -983
439 4032 1472 -298 564 6979 2946 -990
440 4057 1483 -302 565 7001 2958 -997
441 4083 1495 -306 566 7023 2971 -1004
442 4108 1506 -310 567 7045 2983 -1011
443 4133 1517 -314 568 7067 2995 -1019
444 4159 1528 -318 569 7089 3008 -1026
445 4184 1540 -322 570 7110 3020 -1033
126
446 4209 1551 -327 571 7132 3033 -1040
447 4234 1562 -331 572 7154 3045 -1047
448 4260 1573 -335 573 7176 3058 -1054
449 4285 1585 -339 574 7198 3070 -1061
450 4310 1596 -344 575 7219 3083 -1069
451 4335 1607 -348 576 7241 3095 -1076
452 4360 1618 -352 577 7263 3108 -1083
453 4385 1630 -357 578 7284 3120 -1090
454 4410 1641 -361 579 7306 3133 -1098
455 4435 1652 -365 580 7328 3145 -1105
456 4460 1664 -370 581 7349 3158 -1112
457 4485 1675 -374 582 7371 3170 -1120
458 4510 1687 -379 583 7393 3183 -1127
459 4534 1698 -383 584 7414 3195 -1134
460 4559 1709 -388 585 7436 3208 -1142
461 4584 1721 -393 586 7457 3221 -1149
462 4609 1732 -397 587 7479 3233 -1157
463 4633 1743 -402 588 7500 3246 -1164
464 4658 1755 -406 589 7522 3258 -1172
465 4683 1766 -411 590 7543 3271 -1179
466 4707 1778 -416 591 7564 3284 -1187
467 4732 1789 -420 592 7586 3296 -1194
468 4756 1801 -425 593 7607 3309 -1202
469 4781 1812 -430 594 7628 3322 -1210
470 4805 1824 -435 595 7650 3334 -1217
471 4830 1835 -440 596 7671 3347 -1225
472 4854 1847 -444 597 7692 3360 -1233
473 4878 1858 -449 598 7714 3373 -1240
474 4903 1870 -454 599 7735 3385 -1248
475 4927 1881 -459 600 7756 3398 -1256
476 4951 1893 -464 601 7777 3411 -1264
477 4975 1904 -469 602 7799 3423 -1271
478 5000 1916 -474 603 7820 3436 -1279
479 5024 1927 -479 604 7841 3449 -1287
480 5048 1939 -484 605 7862 3462 -1295
481 5072 1951 -489 606 7883 3475 -1303
482 5096 1962 -494 607 7904 3487 -1311
483 5120 1974 -499 608 7925 3500 -1318
484 5144 1985 -504 609 7946 3513 -1326
485 5168 1997 -510 610 7967 3526 -1334
127
486 5192 2009 -515 611 7988 3539 -1342
487 5216 2020 -520 612 8009 3551 -1350
488 5240 2032 -525 613 8030 3564 -1358
489 5264 2044 -530 614 8051 3577 -1366
490 5288 2055 -536 615 8072 3590 -1374
491 5312 2067 -541 616 8093 3603 -1383
492 5335 2079 -546 617 8114 3616 -1391
493 5359 2090 -552 618 8135 3629 -1399
494 5383 2102 -557 619 8156 3642 -1407
495 5407 2114 -562 620 8177 3655 -1415
496 5430 2126 -568 621 8198 3667 -1423
497 5454 2137 -573 622 8219 3680 -1431
498 5478 2149 -579 623 8239 3693 -1440
499 5501 2161 -584 62315 8242 3695 -1441
128
Appendix F
Table F1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in solid
state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 1063 334 -017
299 029 009 000 331 1096 345 -018
300 063 019 000 332 1128 356 -019
301 097 029 000 333 1161 366 -020
302 131 039 000 334 1193 377 -021
303 165 050 000 335 1225 388 -022
304 199 060 -001 336 1258 399 -024
305 233 070 -001 337 1290 410 -025
306 267 081 -001 338 1322 421 -026
307 300 091 -001 339 1355 432 -028
308 334 101 -002 340 1387 443 -029
309 368 112 -002 341 1419 454 -030
310 401 122 -002 342 1451 464 -032
311 435 133 -003 343 1483 475 -033
312 468 143 -003 344 1515 486 -035
313 502 153 -004 345 1547 497 -036
314 535 164 -004 346 1578 508 -038
315 569 174 -005 347 1610 519 -039
316 602 185 -005 348 1642 531 -041
317 635 196 -006 349 1674 542 -043
318 668 206 -006 350 1705 553 -044
319 702 217 -007 351 1737 564 -046
320 735 227 -008 352 1769 575 -048
321 768 238 -009 353 1800 586 -049
322 801 248 -009 354 1832 597 -051
323 834 259 -010 355 1863 608 -053
324 867 270 -011 356 1894 619 -055
325 900 280 -012 357 1926 631 -057
326 932 291 -013 358 1957 642 -059
327 965 302 -014 359 1988 653 -061
328 998 313 -015 35915 1993 655 -061
329 1030 323 -016
129
Table F2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in liquid
state (37515-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2691 926 -083 500 6111 2416 -640
376 2717 936 -085 501 6136 2428 -646
377 2747 948 -088 502 6161 2440 -652
378 2778 959 -091 503 6185 2453 -658
379 2808 971 -094 504 6210 2465 -665
380 2838 982 -096 505 6235 2478 -671
381 2869 994 -099 506 6259 2490 -677
382 2899 1005 -102 507 6284 2502 -683
383 2929 1017 -105 508 6308 2515 -690
384 2959 1028 -108 509 6333 2527 -696
385 2989 1040 -111 510 6357 2540 -702
386 3019 1051 -114 511 6381 2552 -709
387 3049 1063 -117 512 6406 2565 -715
388 3079 1075 -120 513 6430 2577 -721
389 3109 1086 -123 514 6454 2590 -728
390 3138 1098 -126 515 6479 2602 -734
391 3168 1109 -129 516 6503 2615 -741
392 3198 1121 -133 517 6527 2627 -747
393 3227 1132 -136 518 6551 2640 -754
394 3257 1144 -139 519 6575 2652 -760
395 3286 1156 -142 520 6599 2665 -767
396 3316 1167 -146 521 6624 2677 -774
397 3345 1179 -149 522 6648 2690 -780
398 3374 1191 -152 523 6672 2702 -787
399 3403 1202 -156 524 6696 2715 -794
400 3433 1214 -159 525 6719 2727 -800
401 3462 1226 -163 526 6743 2740 -807
402 3491 1237 -166 527 6767 2753 -814
403 3520 1249 -170 528 6791 2765 -821
404 3549 1261 -173 529 6815 2778 -827
405 3578 1272 -177 530 6839 2790 -834
130
406 3606 1284 -180 531 6862 2803 -841
407 3635 1296 -184 532 6886 2815 -848
408 3664 1307 -187 533 6910 2828 -855
409 3693 1319 -191 534 6933 2841 -862
410 3721 1331 -195 535 6957 2853 -869
411 3750 1343 -199 536 6981 2866 -876
412 3778 1354 -202 537 7004 2879 -883
413 3807 1366 -206 538 7028 2891 -890
414 3835 1378 -210 539 7051 2904 -897
415 3864 1390 -214 540 7075 2917 -904
416 3892 1401 -218 541 7098 2929 -911
417 3920 1413 -222 542 7122 2942 -918
418 3948 1425 -226 543 7145 2955 -925
419 3977 1437 -230 544 7168 2967 -932
420 4005 1449 -234 545 7192 2980 -939
421 4033 1460 -238 546 7215 2993 -947
422 4061 1472 -242 547 7238 3005 -954
423 4089 1484 -246 548 7261 3018 -961
424 4117 1496 -250 549 7285 3031 -968
425 4145 1508 -254 550 7308 3044 -976
426 4172 1519 -258 551 7331 3056 -983
427 4200 1531 -262 552 7354 3069 -990
428 4228 1543 -266 553 7377 3082 -998
429 4256 1555 -271 554 7400 3095 -1005
430 4283 1567 -275 555 7423 3107 -1013
431 4311 1579 -279 556 7446 3120 -1020
432 4338 1591 -284 557 7469 3133 -1027
433 4366 1603 -288 558 7492 3146 -1035
434 4393 1614 -292 559 7515 3159 -1042
435 4421 1626 -297 560 7538 3171 -1050
436 4448 1638 -301 561 7561 3184 -1058
437 4475 1650 -306 562 7584 3197 -1065
438 4503 1662 -310 563 7607 3210 -1073
439 4530 1674 -315 564 7629 3223 -1080
440 4557 1686 -319 565 7652 3235 -1088
441 4584 1698 -324 566 7675 3248 -1096
442 4611 1710 -328 567 7697 3261 -1103
443 4638 1722 -333 568 7720 3274 -1111
444 4665 1734 -338 569 7743 3287 -1119
445 4692 1746 -342 570 7765 3300 -1126
131
446 4719 1758 -347 571 7788 3313 -1134
447 4746 1770 -352 572 7811 3326 -1142
448 4773 1782 -356 573 7833 3338 -1150
449 4800 1794 -361 574 7856 3351 -1158
450 4826 1806 -366 575 7878 3364 -1166
451 4853 1818 -371 576 7901 3377 -1173
452 4880 1830 -376 577 7923 3390 -1181
453 4906 1842 -381 578 7945 3403 -1189
454 4933 1854 -386 579 7968 3416 -1197
455 4959 1866 -391 580 7990 3429 -1205
456 4986 1878 -396 581 8012 3442 -1213
457 5012 1890 -401 582 8035 3455 -1221
458 5039 1902 -406 583 8057 3468 -1229
459 5065 1914 -411 584 8079 3481 -1237
460 5091 1926 -416 585 8101 3494 -1245
461 5118 1938 -421 586 8124 3507 -1254
462 5144 1951 -426 587 8146 3520 -1262
463 5170 1963 -431 588 8168 3533 -1270
464 5196 1975 -436 589 8190 3546 -1278
465 5222 1987 -441 590 8212 3559 -1286
466 5248 1999 -447 591 8234 3572 -1294
467 5274 2011 -452 592 8256 3585 -1303
468 5300 2023 -457 593 8278 3598 -1311
469 5326 2035 -463 594 8300 3611 -1319
470 5352 2048 -468 595 8322 3624 -1328
471 5378 2060 -473 596 8344 3637 -1336
472 5404 2072 -479 597 8366 3650 -1344
473 5430 2084 -484 598 8388 3663 -1353
474 5455 2096 -490 599 8410 3676 -1361
475 5481 2108 -495 600 8432 3690 -1369
476 5507 2121 -500 601 8454 3703 -1378
477 5532 2133 -506 602 8475 3716 -1386
478 5558 2145 -512 603 8497 3729 -1395
479 5583 2157 -517 604 8519 3742 -1403
480 5609 2170 -523 605 8541 3755 -1412
481 5634 2182 -528 606 8562 3768 -1420
482 5660 2194 -534 607 8584 3781 -1429
483 5685 2206 -540 608 8606 3795 -1438
484 5710 2219 -545 609 8627 3808 -1446
485 5736 2231 -551 610 8649 3821 -1455
132
486 5761 2243 -557 611 8670 3834 -1464
487 5786 2255 -563 612 8692 3847 -1472
488 5812 2268 -568 613 8713 3860 -1481
489 5837 2280 -574 614 8735 3874 -1490
490 5862 2292 -580 615 8756 3887 -1498
491 5887 2305 -586 616 8778 3900 -1507
492 5912 2317 -592 617 8799 3913 -1516
493 5937 2329 -598 618 8821 3926 -1525
494 5962 2342 -604 619 8842 3940 -1534
495 5987 2354 -610 620 8864 3953 -1542
496 6012 2366 -616 621 8885 3966 -1551
497 6037 2379 -622 622 8906 3979 -1560
498 6062 2391 -628 623 8928 3993 -1569
499 6086 2403 -634 62315 8931 3995 -1570
133
Appendix G
Table G1 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid I state (29815-33715K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 319 578 162 -004
299 024 000 000 320 606 170 -005
300 052 000 000 321 633 179 -005
301 080 007 000 322 660 188 -006
302 108 016 000 323 688 197 -007
303 136 024 000 324 715 205 -007
304 164 032 000 325 742 214 -008
305 192 041 000 326 769 223 -009
306 219 049 000 327 796 232 -009
307 247 058 000 328 823 241 -010
308 275 067 -001 329 851 250 -011
309 303 075 -001 330 878 259 -011
310 330 084 -001 331 905 268 -012
311 358 092 -001 332 932 277 -013
312 386 101 -002 333 959 285 -014
313 413 109 -002 334 985 294 -015
314 441 118 -002 335 1012 303 -016
315 468 127 -003 336 1039 312 -017
316 496 135 -003 337 1066 321 -018
317 523 144 -003 33715 1070 331 -019
318 551 153 -004
Table G2 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid II state (36115-36415K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36115 2433 825 -054
134
362 2454 832 -056
363 2478 841 -059
364 2503 850 -061
36415 2506 851 -062
Table G3 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
liquid state (41115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
41115 3833 1366 -210 518 6604 2649 -772
412 3857 1376 -213 519 6628 2661 -778
413 3885 1387 -217 520 6652 2674 -785
414 3913 1399 -221 521 6675 2686 -792
415 3941 1411 -225 522 6699 2699 -798
416 3969 1422 -229 523 6723 2711 -805
417 3997 1434 -233 524 6747 2723 -812
418 4025 1446 -237 525 6770 2736 -819
419 4053 1457 -241 526 6794 2748 -825
420 4081 1469 -245 527 6818 2761 -832
421 4109 1481 -249 528 6841 2773 -839
422 4137 1493 -253 529 6865 2786 -846
423 4165 1504 -257 530 6888 2798 -853
424 4192 1516 -262 531 6912 2810 -860
425 4220 1528 -266 532 6935 2823 -867
426 4248 1539 -270 533 6959 2835 -873
427 4275 1551 -274 534 6982 2848 -880
428 4303 1563 -279 535 7005 2860 -887
429 4330 1575 -283 536 7029 2873 -894
430 4358 1587 -287 537 7052 2885 -902
431 4385 1598 -292 538 7075 2898 -909
432 4412 1610 -296 539 7098 2910 -916
433 4439 1622 -300 540 7122 2923 -923
434 4467 1634 -305 541 7145 2935 -930
135
435 4494 1646 -309 542 7168 2948 -937
436 4521 1657 -314 543 7191 2960 -944
437 4548 1669 -318 544 7214 2973 -951
438 4575 1681 -323 545 7237 2986 -959
439 4602 1693 -328 546 7260 2998 -966
440 4629 1705 -332 547 7283 3011 -973
441 4656 1716 -337 548 7306 3023 -980
442 4683 1728 -341 549 7329 3036 -988
443 4710 1740 -346 550 7352 3048 -995
444 4736 1752 -351 551 7375 3061 -1003
445 4763 1764 -356 552 7398 3074 -1010
446 4790 1776 -360 553 7420 3086 -1017
447 4816 1788 -365 554 7443 3099 -1025
448 4843 1800 -370 555 7466 3111 -1032
449 4869 1812 -375 556 7489 3124 -1040
450 4896 1823 -380 557 7511 3137 -1047
451 4922 1835 -385 558 7534 3149 -1055
452 4949 1847 -390 559 7557 3162 -1062
453 4975 1859 -395 560 7579 3175 -1070
454 5002 1871 -400 561 7602 3187 -1077
455 5028 1883 -405 562 7625 3200 -1085
456 5054 1895 -410 563 7647 3213 -1093
457 5080 1907 -415 564 7670 3225 -1100
458 5106 1919 -420 565 7692 3238 -1108
459 5132 1931 -425 566 7714 3251 -1116
460 5159 1943 -430 567 7737 3263 -1123
461 5185 1955 -435 568 7759 3276 -1131
462 5211 1967 -440 569 7782 3289 -1139
463 5236 1979 -446 570 7804 3302 -1147
464 5262 1991 -451 571 7826 3314 -1155
465 5288 2003 -456 572 7849 3327 -1162
466 5314 2015 -461 573 7871 3340 -1170
467 5340 2027 -467 574 7893 3352 -1178
468 5366 2039 -472 575 7915 3365 -1186
469 5391 2051 -478 576 7937 3378 -1194
470 5417 2063 -483 577 7960 3391 -1202
471 5442 2075 -488 578 7982 3404 -1210
472 5468 2087 -494 579 8004 3416 -1218
473 5494 2099 -499 580 8026 3429 -1226
474 5519 2111 -505 581 8048 3442 -1234
136
475 5545 2123 -510 582 8070 3455 -1242
476 5570 2135 -516 583 8092 3468 -1250
477 5595 2147 -521 584 8114 3480 -1258
478 5621 2160 -527 585 8136 3493 -1266
479 5646 2172 -533 586 8158 3506 -1274
480 5671 2184 -538 587 8180 3519 -1283
481 5696 2196 -544 588 8201 3532 -1291
482 5722 2208 -550 589 8223 3545 -1299
483 5747 2220 -555 590 8245 3557 -1307
484 5772 2232 -561 591 8267 3570 -1315
485 5797 2244 -567 592 8289 3583 -1324
486 5822 2257 -573 593 8310 3596 -1332
487 5847 2269 -579 594 8332 3609 -1340
488 5872 2281 -585 595 8354 3622 -1349
489 5897 2293 -590 596 8375 3635 -1357
490 5922 2305 -596 597 8397 3648 -1365
491 5947 2317 -602 598 8419 3660 -1374
492 5971 2330 -608 599 8440 3673 -1382
493 5996 2342 -614 600 8462 3686 -1391
494 6021 2354 -620 601 8483 3699 -1399
495 6046 2366 -626 602 8505 3712 -1408
496 6070 2379 -632 603 8526 3725 -1416
497 6095 2391 -638 604 8548 3738 -1425
498 6119 2403 -645 605 8569 3751 -1433
499 6144 2415 -651 606 8591 3764 -1442
500 6169 2427 -657 607 8612 3777 -1451
501 6193 2440 -663 608 8633 3790 -1459
502 6217 2452 -669 609 8655 3803 -1468
503 6242 2464 -675 610 8676 3816 -1476
504 6266 2477 -682 611 8697 3829 -1485
505 6291 2489 -688 612 8719 3842 -1494
506 6315 2501 -694 613 8740 3855 -1503
507 6339 2513 -701 614 8761 3868 -1511
508 6363 2526 -707 615 8782 3881 -1520
509 6388 2538 -713 616 8803 3894 -1529
510 6412 2550 -720 617 8825 3907 -1538
511 6436 2563 -726 618 8846 3920 -1547
512 6460 2575 -733 619 8867 3933 -1555
513 6484 2587 -739 620 8888 3946 -1564
514 6508 2600 -746 621 8909 3959 -1573
137
515 6532 2612 -752 622 8930 3972 -1582
516 6556 2624 -759 623 8951 3985 -1591
517 6580 2637 -765 62315 8954 3987 -1592
138
Appendix H
Table H1 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid I
state (29815-35415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 768 241 -011
299 023 007 000 328 794 249 -011
300 050 015 000 329 820 258 -012
301 077 023 000 330 846 266 -013
302 104 031 000 331 872 275 -014
303 131 039 000 332 898 284 -015
304 158 048 000 333 924 292 -016
305 185 056 -001 334 950 301 -016
306 212 064 -001 335 976 310 -017
307 239 072 -001 336 1002 318 -018
308 265 081 -001 337 1028 327 -019
309 292 089 -001 338 1053 336 -020
310 319 097 -002 339 1079 344 -021
311 345 105 -002 340 1105 353 -022
312 372 114 -002 341 1130 362 -024
313 399 122 -003 342 1156 371 -025
314 425 130 -003 343 1182 379 -026
315 452 139 -004 344 1207 388 -027
316 478 147 -004 345 1233 397 -028
317 505 156 -004 346 1258 406 -029
318 531 164 -005 347 1284 415 -031
319 558 172 -005 348 1309 424 -032
320 584 181 -006 349 1335 433 -033
321 611 189 -007 350 1360 441 -035
322 637 198 -007 351 1385 450 -036
323 663 206 -008 352 1411 459 -037
324 689 215 -008 353 1436 468 -039
325 716 223 -009 354 1461 477 -040
326 742 232 -010 35415 1465 478 -040
139
Table H2 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid 2
state (36215-37315K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36215 2387 777 -046
363 2408 809 -055
364 2432 817 -057
365 2457 826 -060
366 2481 835 -062
367 2506 843 -065
368 2530 852 -067
369 2555 861 -070
370 2579 870 -072
371 2604 879 -075
372 2628 888 -077
373 2653 898 -080
37315 2657 907 -083
Table H3 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in liquid
state (37915-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37915 2966 1025 -100 502 6174 2432 -667
380 2991 1034 -102 503 6198 2444 -674
381 3020 1045 -105 504 6222 2456 -680
382 3048 1056 -108 505 6246 2468 -686
383 3077 1067 -112 506 6270 2480 -692
384 3105 1078 -115 507 6294 2492 -699
385 3134 1089 -118 508 6317 2504 -705
386 3162 1100 -121 509 6341 2516 -711
387 3191 1111 -124 510 6365 2528 -718
140
388 3219 1122 -127 511 6388 2541 -724
389 3247 1133 -130 512 6412 2553 -730
390 3275 1144 -134 513 6436 2565 -737
391 3304 1155 -137 514 6459 2577 -743
392 3332 1166 -140 515 6483 2589 -750
393 3360 1177 -144 516 6506 2601 -756
394 3388 1188 -147 517 6530 2613 -763
395 3416 1199 -150 518 6553 2625 -769
396 3444 1210 -154 519 6577 2638 -776
397 3472 1221 -157 520 6600 2650 -782
398 3500 1232 -161 521 6624 2662 -789
399 3527 1243 -164 522 6647 2674 -796
400 3555 1254 -168 523 6670 2686 -802
401 3583 1265 -171 524 6694 2698 -809
402 3611 1276 -175 525 6717 2711 -816
403 3638 1287 -179 526 6740 2723 -822
404 3666 1299 -182 527 6763 2735 -829
405 3693 1310 -186 528 6786 2747 -836
406 3721 1321 -190 529 6810 2760 -843
407 3748 1332 -193 530 6833 2772 -850
408 3776 1343 -197 531 6856 2784 -856
409 3803 1354 -201 532 6879 2796 -863
410 3830 1366 -205 533 6902 2809 -870
411 3857 1377 -209 534 6925 2821 -877
412 3885 1388 -213 535 6948 2833 -884
413 3912 1399 -216 536 6971 2845 -891
414 3939 1410 -220 537 6994 2858 -898
415 3966 1422 -224 538 7017 2870 -905
416 3993 1433 -228 539 7040 2882 -912
417 4020 1444 -232 540 7063 2895 -919
418 4047 1455 -236 541 7086 2907 -926
419 4074 1467 -240 542 7108 2919 -933
420 4101 1478 -245 543 7131 2932 -940
421 4128 1489 -249 544 7154 2944 -947
422 4154 1500 -253 545 7177 2957 -955
423 4181 1512 -257 546 7199 2969 -962
424 4208 1523 -261 547 7222 2981 -969
425 4234 1534 -265 548 7245 2994 -976
426 4261 1546 -270 549 7267 3006 -984
427 4288 1557 -274 550 7290 3019 -991
141
428 4314 1568 -278 551 7313 3031 -998
429 4341 1580 -282 552 7335 3044 -1005
430 4367 1591 -287 553 7358 3056 -1013
431 4393 1602 -291 554 7380 3068 -1020
432 4420 1614 -296 555 7403 3081 -1028
433 4446 1625 -300 556 7425 3093 -1035
434 4472 1636 -305 557 7448 3106 -1042
435 4499 1648 -309 558 7470 3118 -1050
436 4525 1659 -314 559 7492 3131 -1057
437 4551 1671 -318 560 7515 3143 -1065
438 4577 1682 -323 561 7537 3156 -1072
439 4603 1694 -327 562 7560 3169 -1080
440 4629 1705 -332 563 7582 3181 -1087
441 4655 1716 -336 564 7604 3194 -1095
442 4681 1728 -341 565 7626 3206 -1103
443 4707 1739 -346 566 7649 3219 -1110
444 4733 1751 -351 567 7671 3231 -1118
445 4759 1762 -355 568 7693 3244 -1126
446 4785 1774 -360 569 7715 3257 -1133
447 4810 1785 -365 570 7737 3269 -1141
448 4836 1797 -370 571 7759 3282 -1149
449 4862 1808 -375 572 7782 3294 -1157
450 4888 1820 -379 573 7804 3307 -1164
451 4913 1832 -384 574 7826 3320 -1172
452 4939 1843 -389 575 7848 3332 -1180
453 4964 1855 -394 576 7870 3345 -1188
454 4990 1866 -399 577 7892 3358 -1196
455 5015 1878 -404 578 7914 3370 -1204
456 5041 1889 -409 579 7936 3383 -1212
457 5066 1901 -414 580 7957 3396 -1220
458 5092 1913 -419 581 7979 3408 -1228
459 5117 1924 -424 582 8001 3421 -1236
460 5142 1936 -430 583 8023 3434 -1244
461 5167 1947 -435 584 8045 3447 -1252
462 5193 1959 -440 585 8067 3459 -1260
463 5218 1971 -445 586 8088 3472 -1268
464 5243 1982 -450 587 8110 3485 -1276
465 5268 1994 -456 588 8132 3498 -1284
466 5293 2006 -461 589 8154 3510 -1292
467 5318 2017 -466 590 8175 3523 -1300
142
468 5343 2029 -472 591 8197 3536 -1308
469 5368 2041 -477 592 8219 3549 -1317
470 5393 2053 -482 593 8240 3562 -1325
471 5418 2064 -488 594 8262 3574 -1333
472 5443 2076 -493 595 8283 3587 -1341
473 5468 2088 -499 596 8305 3600 -1350
474 5493 2100 -504 597 8327 3613 -1358
475 5517 2111 -510 598 8348 3626 -1366
476 5542 2123 -515 599 8370 3639 -1375
477 5567 2135 -521 600 8391 3652 -1383
478 5592 2147 -526 601 8413 3664 -1391
479 5616 2158 -532 602 8434 3677 -1400
480 5641 2170 -537 603 8455 3690 -1408
481 5665 2182 -543 604 8477 3703 -1417
482 5690 2194 -549 605 8498 3716 -1425
483 5715 2206 -554 606 8520 3729 -1434
484 5739 2218 -560 607 8541 3742 -1442
485 5763 2229 -566 608 8562 3755 -1451
486 5788 2241 -572 609 8583 3768 -1459
487 5812 2253 -578 610 8605 3781 -1468
488 5837 2265 -583 611 8626 3794 -1477
489 5861 2277 -589 612 8647 3807 -1485
490 5885 2289 -595 613 8668 3820 -1494
491 5910 2301 -601 614 8690 3833 -1503
492 5934 2313 -607 615 8711 3846 -1511
493 5958 2324 -613 616 8732 3859 -1520
494 5982 2336 -619 617 8753 3872 -1529
495 6006 2348 -625 618 8774 3885 -1538
496 6030 2360 -631 619 8795 3898 -1546
497 6055 2372 -637 620 8816 3911 -1555
498 6079 2384 -643 621 8837 3924 -1564
499 6103 2396 -649 622 8858 3937 -1573
500 6127 2408 -655 623 8879 3950 -1582
501 6151 2420 -661 62315 8883 3952 -1583
143
Appendix I
Table I1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in solid state (29815-35315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 1171 366 -017
299 035 010 000 328 1211 379 -018
300 076 023 000 329 1250 392 -019
301 117 035 000 330 1290 405 -021
302 158 048 000 331 1330 418 -022
303 199 060 000 332 1369 431 -023
304 240 072 -001 333 1409 444 -025
305 281 085 -001 334 1448 458 -026
306 322 097 -001 335 1488 471 -028
307 363 110 -002 336 1527 484 -029
308 404 122 -002 337 1566 497 -031
309 445 135 -002 338 1605 510 -032
310 486 148 -003 339 1644 524 -034
311 526 160 -003 340 1683 537 -036
312 567 173 -004 341 1722 550 -037
313 608 186 -005 342 1761 563 -039
314 648 198 -005 343 1800 577 -041
315 689 211 -006 344 1839 590 -043
316 729 224 -007 345 1877 603 -044
317 770 237 -007 346 1916 617 -046
318 810 250 -008 347 1955 630 -048
319 850 262 -009 348 1993 643 -050
320 891 275 -010 349 2031 657 -052
321 931 288 -011 350 2070 670 -054
322 971 301 -012 351 2108 683 -056
323 1011 314 -013 352 2146 697 -059
324 1051 327 -014 353 2184 710 -061
325 1091 340 -015 35315 2190 712 -061
326 1131 353 -016
144
Table I2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in liquid state (39115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
39115 4413 1056 -191 508 8890 3521 -978
392 4450 1535 -195 509 8924 3538 -986
393 4492 1549 -200 510 8959 3556 -995
394 4535 1566 -204 511 8993 3574 -1004
395 4577 1583 -209 512 9027 3591 -1013
396 4620 1599 -213 513 9062 3609 -1022
397 4662 1616 -218 514 9096 3626 -1031
398 4704 1633 -223 515 9130 3644 -1041
399 4746 1650 -227 516 9164 3661 -1050
400 4789 1666 -232 517 9198 3679 -1059
401 4831 1683 -237 518 9232 3697 -1068
402 4872 1700 -242 519 9266 3714 -1077
403 4914 1717 -247 520 9300 3732 -1087
404 4956 1734 -252 521 9334 3750 -1096
405 4997 1751 -257 522 9368 3767 -1105
406 5039 1767 -262 523 9402 3785 -1115
407 5080 1784 -267 524 9435 3802 -1124
408 5122 1801 -272 525 9469 3820 -1134
409 5163 1818 -277 526 9503 3838 -1143
410 5204 1835 -282 527 9536 3855 -1152
411 5245 1852 -287 528 9570 3873 -1162
412 5286 1869 -293 529 9603 3891 -1172
413 5327 1885 -298 530 9637 3908 -1181
414 5368 1902 -303 531 9670 3926 -1191
415 5409 1919 -309 532 9703 3944 -1201
416 5450 1936 -314 533 9737 3962 -1210
417 5490 1953 -320 534 9770 3979 -1220
418 5531 1970 -325 535 9803 3997 -1230
419 5571 1987 -331 536 9836 4015 -1240
420 5612 2004 -336 537 9869 4032 -1249
421 5652 2021 -342 538 9902 4050 -1259
145
422 5692 2038 -347 539 9935 4068 -1269
423 5732 2055 -353 540 9968 4086 -1279
424 5772 2072 -359 541 10001 4104 -1289
425 5812 2089 -365 542 10034 4121 -1299
426 5852 2106 -371 543 10066 4139 -1309
427 5892 2123 -376 544 10099 4157 -1319
428 5932 2140 -382 545 10132 4175 -1329
429 5971 2157 -388 546 10165 4192 -1340
430 6011 2174 -394 547 10197 4210 -1350
431 6051 2191 -400 548 10230 4228 -1360
432 6090 2208 -406 549 10262 4246 -1370
433 6129 2225 -412 550 10295 4264 -1380
434 6169 2242 -419 551 10327 4282 -1391
435 6208 2259 -425 552 10359 4299 -1401
436 6247 2276 -431 553 10392 4317 -1411
437 6286 2293 -437 554 10424 4335 -1422
438 6325 2310 -444 555 10456 4353 -1432
439 6364 2327 -450 556 10488 4371 -1443
440 6403 2344 -456 557 10520 4389 -1453
441 6442 2361 -463 558 10553 4407 -1464
442 6480 2378 -469 559 10585 4424 -1474
443 6519 2395 -476 560 10617 4442 -1485
444 6557 2412 -482 561 10648 4460 -1496
445 6596 2429 -489 562 10680 4478 -1506
446 6634 2446 -495 563 10712 4496 -1517
447 6673 2464 -502 564 10744 4514 -1528
448 6711 2481 -509 565 10776 4532 -1538
449 6749 2498 -515 566 10808 4550 -1549
450 6787 2515 -522 567 10839 4568 -1560
451 6825 2532 -529 568 10871 4586 -1571
452 6863 2549 -536 569 10902 4604 -1582
453 6901 2566 -543 570 10934 4622 -1593
454 6939 2584 -550 571 10965 4640 -1604
455 6977 2601 -557 572 10997 4658 -1615
456 7015 2618 -564 573 11028 4676 -1626
457 7052 2635 -571 574 11060 4694 -1637
458 7090 2652 -578 575 11091 4712 -1648
459 7128 2670 -585 576 11122 4730 -1659
460 7165 2687 -592 577 11154 4748 -1670
461 7202 2704 -599 578 11185 4766 -1681
146
462 7240 2721 -606 579 11216 4784 -1692
463 7277 2738 -614 580 11247 4802 -1704
464 7314 2756 -621 581 11278 4820 -1715
465 7351 2773 -628 582 11309 4838 -1726
466 7388 2790 -636 583 11340 4856 -1737
467 7425 2807 -643 584 11371 4874 -1749
468 7462 2825 -650 585 11402 4892 -1760
469 7499 2842 -658 586 11433 4910 -1772
470 7536 2859 -665 587 11464 4928 -1783
471 7573 2877 -673 588 11495 4946 -1794
472 7609 2894 -680 589 11525 4964 -1806
473 7646 2911 -688 590 11556 4982 -1817
474 7682 2928 -696 591 11587 5001 -1829
475 7719 2946 -703 592 11617 5019 -1841
476 7755 2963 -711 593 11648 5037 -1852
477 7792 2980 -719 594 11678 5055 -1864
478 7828 2998 -727 595 11709 5073 -1876
479 7864 3015 -735 596 11739 5091 -1887
480 7900 3032 -742 597 11770 5109 -1899
481 7937 3050 -750 598 11800 5128 -1911
482 7973 3067 -758 599 11831 5146 -1923
483 8009 3084 -766 600 11861 5164 -1935
484 8045 3102 -774 601 11891 5182 -1946
485 8080 3119 -782 602 11921 5200 -1958
486 8116 3137 -791 603 11952 5218 -1970
487 8152 3154 -799 604 11982 5237 -1982
488 8188 3171 -807 605 12012 5255 -1994
489 8223 3189 -815 606 12042 5273 -2006
490 8259 3206 -823 607 12072 5291 -2018
491 8294 3224 -832 608 12102 5309 -2030
492 8330 3241 -840 609 12132 5328 -2042
493 8365 3259 -848 610 12162 5346 -2055
494 8401 3276 -857 611 12192 5364 -2067
495 8436 3293 -865 612 12222 5382 -2079
496 8471 3311 -873 613 12252 5401 -2091
497 8506 3328 -882 614 12281 5419 -2103
498 8542 3346 -890 615 12311 5437 -2116
499 8577 3363 -899 616 12341 5456 -2128
500 8612 3381 -908 617 12370 5474 -2140
501 8647 3398 -916 618 12400 5492 -2153
147
502 8681 3416 -925 619 12430 5510 -2165
503 8716 3433 -934 620 12459 5529 -2178
504 8751 3451 -942 621 12489 5547 -2190
505 8786 3468 -951 622 12518 5565 -2203
506 8820 3486 -960 623 12548 5584 -2215
507 8855 3503 -969 62315 12552 5602 -2217
iii
DEDICATION
This thesis is dedicated to everyone who helped me and guided me through the trials and
tribulations of creating this manuscript In particular my family and close friends who stood by
me throughout the time taken to complete this masterpiece
iv
ACKNOWLEDGEMENTS
I am pleased to express my gratitude and appreciation to my advisor Professor Ramana
G Reddy for his patience and guidance during my graduate study and the entire research work I
am greatly benefited from his experience knowledge and enthusiasm for scientific research
I would like to express my sincere thanks to Dr Nitin Chopra and Dr Yang-Ki Hong for
serving on my committee Their valuable suggestions and comments are very insightful for my
research work
I would like to thank all the research colleagues of Dr Reddy‟s research group special
thanks to Dr Divakar Mantha for his valuable suggestions and comments I would like to extend
my gratitude to US Department of Energy for the financial support
Finally I would like to thank my parents and my fianceacutee whose invaluable
understanding and loving support helped me through the difficult times
v
TABLE OF CONTENTS
ABSTRACT ii
DEDICATION iii
ACKNOWLEDGEMENTS iv
LIST OF TABLES viii
LIST OF FIGURES x
CHAPTER 1 INTRODUCTION 1
CHAPTER 2 LITERATURE REVIEW 11
21 Melting point 11
22 Density 15
23 Heat capacity 18
CHAPTER 3 OBJECTIVES 22
CHAPTER 4 THERMODYNAMIC MODELING OF SALT SYSTEMS 24
41 Thermodynamic modeling 24
42 Calculations 27
vi
CHAPTER 5 EXPERIMENTAL PROCEDURE 30
51 Melting point determination of molten salt mixtures 30
511 Materials 30
512 Apparatus and Procedure 30
52 Heat Capacity determination of molten salt mixtures 32
53 Density determination of molten salt mixtures 33
CHAPTER 6 RESULT AND DISCUSSION 34
61 Melting point determination 34
611 DSC equipment calibration 34
612 Results 35
613 Discussion 41
62 Heat capacity determination 51
621 Heat capacity calibration 51
622 Results 52
623 Thermodynamic properties 55
624 Discussion of Gibbs energy change for molten salts 84
63 Density determination 86
vii
631 Density calibration 86
632 Results and discussions 82
64 Thermal energy storage density of molten salts 90
CHAPTER 7 CONCLUSION 94
REFERENCES 96
APPENDIX 104
APPENDIX A 104
APPENDIX B 109
APPENDIX C 114
APPENDIX D 118
APPENDIX E 123
APPENDIX F 128
APPENDIX G 133
APPENDIX H 138
APPENDIX I 143
viii
LIST OF TABLES
21 Melting point of various nitrate salt systems 12
22 Melting point of various carbonate salt systems 13
23 Melting point of various fluoridechloride salt systems 14
24 Melting point of various hydroixde salt systems 15
25 Density coefficients A and B of nitrate salts 16
26 Density coefficients A and B of carbonate salts 17
27 Density coefficients A and B of chloridefluoride salts 17
28 Density coefficients A and B of molten salt mixture with hydroxide salts 18
29 Heat capacity of alkali nitrate salt at 500oC 19
210 Heat capacity of alkali carbonate salt at 500oC 19
211 Heat capacity of fluoridechloride salt at 500oC 20
212 Heat capacity of hydroxide salt at 500oC 21
41 Calculated composition and melting point for multi-component systems 29
61 Calibration data of melting points with different samples 35
62 DSC results of melting point transition point and change of enthalpy 41
ix
63 Fusion and solid phase transition temperature for individual salts 42
64 Melting points of candidate systems as function of temperatures 51
65 Calibration data of heat capacities with different samples 52
66 Heat capacity of selected new TES molten salt mixtures 54
67 Change of Gibbs energy values at 62315K for molten salt systems 85
68 Calibration of density measurements with different pure nitrate salts 86
69 Coefficient of A and B for density determination of salt 1 to salt 9 87
610 Extrapolated value of density and heat capacity at 500oC of salt 1 to salt 9 91
611 Energy density of salt 1 to salt 9 compare to solar salt 92
612 Gravimetric storage densities for solar salt and new molten salts 93
x
LIST OF FIGURES
11 Theoretical and engineering energy conversion efficiency as function of temperature 6
12 Gravimetric storage density for different energy storage systems
as function of temperature 8
51 Photography of set-up for DSC equipment 31
61 Melting point calibration with indium sample 34
62 Melting point calibration with KNO3 sample 35
63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt 36
64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt 37
65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt 37
66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt 38
67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt 38
68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt 39
69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt 39
610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt 40
611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN Salt 40
612 DSC plot of 698wt KNO3 -302wt NaNO2 binary system 43
xi
613 DSC plot of 270wt NaNO3-730wt KNO3 binary system 45
614 DSC plot of 458wtLiNO3-542wtKNO3 binary system 45
615 DSC plot of 460wt NaNO3-540wt KNO3 binary system 46
616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 20oCmin heating rate 47
616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 5oCmin heating rate 48
617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 5oCmin heating rate 49
617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 20oCmin heating rate 49
618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system
as function of temperature 53
619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K 54
620 Change of Gibbs energy as function of temperature for molten salt systems 85
621 The densities of the salt 1 to salt 5 as function of temperature 87
622 The densities of the salt 6 to salt 9 as function of temperature 89
623 Densities of the salt 1 salt 2 as function of temperature compared to
the equimolar NaNO3-KNO3 binary system and pure KNO3 90
624 Gravimetric storage density comparison of different energy storage
xii
systems as function of temperature 93
1
CHAPTER 1
INTRODUCTION
Renewable energy sources such as wind solar water power geothermal and biomass are
playing more and more significant role in our energy supply Because the cheap cost and infinite
amount of energy storage inside the resource solar energy is emphasized since 20th
century and
viewed as promising alternative method to satisfy the large energy consumption every day in the
world reduce the emission of carbon and strengthen the economy
The wind energy was used as a clean energy to generate electricity back to late 19th
century
However this renewable energy source was not emphasized due to the cheap price of fossil fuel
The re-emergence happened in mid 1950s when the amount of traditional energy source was
found apparently decrease The development of wind energy usage continued and in 1990 the
first mega-watt wind turbine was launched which was viewed as a symbol of shift to large scale
wind energy utilization [1-2] The modern application of wind energy mainly relies on wind
turbine On the basis of aerodynamic wind turbine generates certain net positive torque on
rotating shaft and then converts the mechanical power to electrical power As an electrical power
generator wind turbine is connected to some electrical network to transport the electricity to
battery charging utilities residential power systems and large scale energy consuming systems
In general most of wind turbines are small scale and can only generate 10KW electrical power
Only few of the wind turbine systems operate with capacity as large as 5MW Although the
usage of wind energy can reduce the emission of carbon oxide the noise pollution and high cost
2
limit its large scale application Since the wind is not transportable the electrical energy can only
be generated where the wind blows which also decrease the flexibility of wind energy
Water power is another term of alternative power supply and it was used for irrigation
operating machines like watermill even before the development of electrical power The modern
application of water power is to generate electricity by using the gravitational force of falling or
flowing water These days there are various ways for the water power application The most
traditional method is to store the water in dam and generate electricity by converting the
potential energy pump storage is a different way to utilize water power and can change its
output depending on the energy demand by moving water between reservoirs at different
elevations In the low energy demand period excess energy is used to lift water to the higher
level while in the peak period of energy demand the water is released back to the lower
elevation through water turbine Water power can also be converted by taking advantage of
naturally raise and fall of tide to satisfy the demand of electrical energy consumption [3]
Although the usage of water power can reduce the emission of carbon dioxide and cost it will
destroy the ecosystem because of the large land required for construction There will be methane
emission from the reservoir the potential failure hazard of dam is also a fatal issue and flow
shortage caused by drought may also create serious problem As result of that water power
technique is not a long-term alternative choice
Geothermal energy is the energy form generated inside the earth At the very beginning of
the planet formation a large amount of thermal energy was stored from the radioactive decay of
minerals volcanic activity and solar energy absorption Because of the temperature difference
3
between the core and the surface of planet the thermal energy stored inside the earth is driven to
the outer surface in the form of heat This form of renewable energy source can be applied to
generate electrical power and heat for industrial space and agricultural applications
Theoretically the deposited amount of geothermal energy is adequate to supply the energy
consumption in the world However most of the geothermal energy is stored deeply near the
core of the earth the deep drilling and exploration of geothermal energy is very expensive and
limits the large-scale use of this renewable energy source [4]
Biomass is a renewable energy source used to generate heat or electricity with living or
recently living organism such as wood waste (hydrogen) gas and alcohol fuels The biomass
energy can be converted to electrical energy by thermal method such as combustion pyrolysis
and gasification Several specific chemical processes may also be able to convert the biomass
energy to other forms The main problem arise from application of biomass is air pollution which
contains carbon monoxide NOx (nitrogen oxides) VOCs (volatile organic compounds)
particulates and other pollutants And the level of air pollution to some extent is even above that
of traditional fuel resource Some other possible issue like transportation and sink of carbon also
limit the wide usage of this type of alternative energy [5]
Among all the renewable energy sources solar energy is the most suitable alternative
energy for our future life It is clean cheap abundant without any noise air pollution no
transportation issue and easy to be obtained anywhere in the earth Inside the core of the Sun
hydrogen fuses into helium with a rate of 7times1011
kgs and generates very powerful nucleation
power This type of nucleation explosion creates ultra high temperature in the core of the Sun
4
which reaches approximately 16 million K degrees Although the Sun is not perfectly black body
it still radiates abundant power with the energy density as 16times107 wattsm
2 [6-7] Because of the
enough amount of hydrogen underneath the surface of the Sun the radiation given arise of from
the nucleation explosion can continue at least 5 million years with the same rate and strength
The energy reaching the earth is vastly reduced mainly caused by the absorption and spreading
of the radiation It is easily to understand that there are numerous amorphous objects all around
the entire universe which can absorb certain portion of the radiation for the Sun Moreover the
light generated from the spherical object such as the Sun fills all the available space between the
origin to the destination Even though the energy will not be lost in the travelling process due to
the long distance between the Sun to the earth the surface area of the sphere which is formed
with the Sun as center and the distance as radius is much larger than that of the earth As the
result of that only 1340Wm2 finally reaches the upmost surface of the earth Even though the
final amount of the received solar energy is very small compared to that is initially radiated from
the Sun the average daily solar radiation falling on one area in the continental United States is
equivalent in total energy content to 11 barrels of oil In summary the solar energy itself is
relatively unlimited useful clean and almost unexploited energy and definitely can behave as
the promising mean for the future energy supply [8]
There are several different methods to take advantage of the solar energy and all the
methods can be distinguished into three group solar parabolic trough solar tower and solar dish
Parabolic trough is constructed by silver coated parabolic mirror and there is a Dewar tube going
through the length of the mirror and set on the focal point all the radiation is concentrated on the
tube and transfer by heat transfer fluid to the thermal energy storage unit Solar tower are used to
5
capture solar energy with thousands of mirrors and focus the concentrated sunlight to the top of
the tower which is located in the middle of the heliostats The thermal energy storage medium
within the tower was heated to high temperature and transferred to thermal energy storage tank
and eventually sent to steam pump The solar dish is built with a large reflective parabolic dish
which concentrates all the received sunlight to one spot There is normally a receiver located on
the focal point and transform the solar energy to other forms of useful energy The working
upper limit temperature of solar parabolic trough system is the lowest among these three systems
normally its maximum working temperature is within the range from 400-500oC the solar tower
has higher maximum working temperature which ranges from 500-1000oC the solar dish has the
highest working upper limit temperature which reaches 700-1200oC [9]
The energy conversion efficiency is the most concerned parameter in the solar energy
storage application and the theoretical and real engineering efficiency are given in fig 11 as
function of temperature The theoretical conversion efficiency can be up to 80 while in real
application the value is always less than 70 regardless of collectors The actual efficiency
increases with temperature in the whole working temperature As a result of that the thermal
energy storage materials in solar parabolic trough for instance should be able to work stably at
the upper limit temperature of this type of collection system which is 500oC to ensure the highest
efficiency [9 10]
6
Fig 11 Theoretical and engineering energy conversion efficiency as function of
temperature
Solar energy can be stored in three major forms sensible heat latent heat and
thermochemical heat Sensible heat storage was utilized based on the heat capacity and the
change as function of temperature of storage materials in the charging and discharging process
which correspond to the absorbing and withdrawing energy processes respectively The sensible
heat stored from the melting point to the maximum working temperature can be expressed by
equation 1 [9]
[1]
Where m is the mass of storage material Tmp and TH are melting point temperature and high
temperature in the same phase respectively Cp(T) is the heat capacity at different temperature
Because the sensible heat storage materials remain in a single phase in the working temperature
range the charging and discharging processes are completely reversible for unlimited cycles
7
Latent heat storage is operated by absorbing and withdrawing energy in the charging and
discharging processes accompanied with fusion of materials [9] The latent heat collected
throughout the working temperature range can be expressed by equation 2 as following
[2]
Where T is temperature in solid state Tmp is melting point temperature of storage material TH is
the high temperature in liquid state and is enthalpy of fusion
Thermochemical heat storage is based on the heat capacity and its change as function of
temperature accompanied with chemical reaction The thermochemical heat collected throughout
the working temperature range can be expressed by equation 3
[3]
Where TL is the low temperature before the reaction TR is the reaction temperature and
is the enthalpy of chemical reaction Because of the destruction of the chemical bonds
in the reaction process the charging and discharging process cannot be completely reversible
which reduces the stability and recyclability of storage operation [10]
Sensible energy storage method is chosen to ensure the efficient usage of solar energy for
parabolic trough system of which the maximum working temperature ranges from 400-500oC
Different from thermochemical heat storage the sensible heat storage can achieve completely
reversible working condition under unlimited cycles Also fig 12 illustrates that the sensible
heat storage materials mainly work in the working temperature range for parabolic trough system
8
and the gravimetric energy storage densities of sensible heat is higher than that of latent heat
materials [9 -11]
Fig 12 Gravimetric storage density for different energy storage systems as function of
temperature
Various materials are chosen to serve as thermal energy storage fluid for sensible heat
such as water thermal oil ionic liquid and molten salt [12] The properties of different heat
transfer fluid determine the performance of solar energy heating system In these days the
efficiency and cost of output of electrical power mainly relies on the parabolic trough solar
power plant and the thermal storage fluid [12] A large investment cost is needed to dispatch
100MW to 200MW energy by consuming the energy transfer fluids Given by this situation the
development of new thermal storage fluid with higher thermal energy storage density is
paramount to lower the expense for generating energy and a lot of effect has been put on design
of new systems [13-16]
9
Water is commonly used as heat transfer and thermal energy storage fluid in industry
because of its low cost high heat capacity and high thermal conductivity However the
limitation for using this medium is also obvious that the temperature range within which the
liquid state can be assured is too small It is well know that water can only serve as thermal
energy storage liquid above the freezing point 0oC and below the boiling temperature 100
oC In
practical experiment the actual temperature range is even less than 100oC because of the large
amount of weight loss near the boiling temperature due to the high vapor pressure Water is
possible to work above 100oC only if high pressure is also applied to avoid the phase
transformation but the cost will be highly increased Accordingly water is only suitable to work
in low temperature below 100oC
Thermal oils are also being used in the parabolic trough solar power plant and have very
low melting point as low as 12oC [17 18] However the application of the oil for the thermal
energy storage liquid is limited by some disadvantages from the physic-chemical properties The
upper limit for this oil is only 300oC and above that the liquid state cannot be maintained
Moreover the low thermal decomposition temperature low density and low heat capacity result
in limited thermal energy storage capacity Since the working temperature range is so narrow the
rankie cycle efficiency is reduced when using the synthetic oil and the cost for generating power
is considered to be very expensive [19 20]
Ionic liquid is another medium served as thermal energy storage fluid The liquid
temperature range of ionic liquid is large which is one of the main advantages of this type of
material The high heat capacity and density ensure the efficiency of thermal energy storage of
10
ionic liquid What‟s more the excellent chemical stability and little vapor pressure increase the
lifetime [21-24] However as a result of the very serve corrosion problem to the liquid container
and the high cost the usage of ionic liquid is still limited
Considering various relative physic-chemical properties of thermal energy storage system
molten salts have been proposed as a suitable group for a wide temperature range application
They are being emphasized in the solar energy applications because of their low melting point
and high upper limit which can increase the stable working range The high heat capacity
increases the thermal energy storage density of the heat storage system excellent thermal
stability and negligible vapor pressure ensure the steadiness of cyclic repeating in the lifetime
[25] low viscosity strengths the mobility and efficiency of the thermal storage liquid low
utilization cost reduce the investment and protect the economy The liquidus temperature range
of the molten salt varies from 150-600oC combination of various salts can bring the melting
down and further increase the working temperature range Due to these properties molten salts
can be excellent thermal energy storage fluid in the solar power generation system
11
CHAPTER 2
LITERATURE REVIEW
Several physical and thermodynamic properties of thermal energy storage fluid play
significant role in determining the efficiency and performance of solar energy storage systems In
order to evaluate the feasibility of systems the physic-chemical properties of several molten salts
should be reviewed The three determining parameter which directly affect the thermal energy
storage capacity in systems are melting point heat capacity and density
There are large amount of melting point data available in the literature for various molten
salt system in previous literatures while those with melting point less than 120oC is very limited
All the previous study on molten salt system revealed that five group of molten salts are
emphasized and commonly used alkai or alkaline nitrates carbonates sulphates chloride and
hydroxides Although most of the systems have the same group of cation the melting point
varies a lot from one to anther due to the different effect of anions
21 Melting point
The melting points of individual and multi-component nitratenitrite systems are listed in
Table 21[26-31] Among those systems solar salt (NaNO3KNO3 6040) is the thermal energy
storage medium which is currently being used with the freezing point of 221oC [27] Although
the melting point for this system is highest in all the candidate mixtures in this group the lowest
12
combined compound cost makes it widely used in solar energy storage field Another ternary
system HITEC which contains NaNO3 KNO3 and NaNO2 has freezing point of 141 oC [28]
This combination brings the melting point down but the lack of combination of optimum features
limits its further application [29] Some mixtures such as LiNO3-Ca(NO3)2-KNO3 are not often
utilized because they increase the compound cost at the same time of lowering the melting point
to around 120oC [30] moreover the decreased melting point is still high compared to the
organic oil There are also several systems have the melting points less than 100oC or even 60
oC
they are not used in the parabolic trough solar power plant due to the decomposition of some
components during high temperature [31]
Table 21 Melting point of various nitrate salt systems
Compound Melting Point (ordmC)
LiNO3 253
NaNO3 307
KNO3 334
Ca(NO3)2 561
Sr(NO3)2 570
Ba(NO3)2 590
NaNO3-NaNO2 221
NaNO3-NaNO2-KNO3 141
NaNO3-KNO3-CaNO3 133
LiNO3-KNO3-NaNO3 120
KNO3-CaNO3-LiNO3 117
LiNO3-KNO3-NHNO3 92
KNO3-NHNO3-AgNO3 52
The melting points of individual and multi-component carbonate systems are listed in
Table 22 [26 32 33] Different from the nitrate salts the melting points for both the individual
13
and multi-component carbonate systems are on the higher side The lowest melting point is
achieved with lithium sodium and potassium carbonate ternary system whose melting point is
still 277oC higher than that of the nitrate ternary system with the same cations [32] Besides
because of the thermal decomposition issue the choice of component involved in the multi-
component carbonate systems is limited Some salt like CaCO3 doesn‟t have stable form at high
temperature and the lack of multi-component system reduces the chance of the synthesis of low
melting point salt mixtures Even though this group of salt is not thermally stable and the
working temperature range is relatively small it is still viewed as possible candidate working at
high temperature due to its low price
Table 22 Melting point of various carbonate salt systems
Compound Melting Point (ordmC)
Li2CO3 732
Na2CO3 858
K2CO3 900
MgCO3 990
Na2CO3-K2CO3 710
Li2CO3-Na2CO3 496
Li2CO3-K2CO3 488
Li2CO3-K2CO3-Na2CO3 397
Alkali and Alkaline fluoridechloride salts are also selected as one possible choice as the
thermal energy storage fluid and the melting point examined from previous literatures are given
in table 23 [34-38] A lot of study has been done for this group of salt and the melting points
were found in the same range as the carbonate group And for the pure salt metal chloride salts
have lower melting point than metal fluoride ones
14
Table 23 Melting point of various fluoridechloride salt systems
Compound Melting Point (ordmC)
LiF 849
NaF 996
KF 858
LiCl 610
NaCl 801
KCl 771
LiF-KF 493
LiF-NaF 652
LiCl-KF 487
LiF-NaF-KF 454
LiF-NaF-KF-MgF2 449
LiF-KF-BaF2 320
LiF-KF-CsF-RbF 256
Several studies were also conducted to determine the melting point of molten hydroxide
salts and the results are shown in Table24 The data of pure salts and multi-component mixtures
merely in this group were not much determined in the literatures Generally they are mixed with
other groups of anion and form some low melting point salt mixtures [39-42] On the basis of the
previous literature data alkali hydroxide salts and their mixture with salts in other groups have
relatively lower melting point compared with pure carbonate and fluoride chloride group salt
mixtures Most of the melting points given in Table 4 are lower than 300oC sodium potassium
hydroxide binary mixture even reaches the melting point below 200oC Accordingly relatively
large temperature range can be obtained by using hydroxide salt mixtures or adding them as
additive
15
Table 24 Melting point of various hydroixde salt systems
Compound Melting Point (ordmC)
LiOH-LiF 427
NaOH-KOH 170
LiOH-NaOH 213
NaOH-NaNO2 232
NaOH-NaNO3 237
NaOH-NaCl-NaNO3 242
NaOH-NaCl-Na2CO3 282
22 Density
For the solar energy storage system density for the thermal energy storage fluid is also
essential parameter The density is needed for the size calculation as function of temperature and
assessing for the thermal stability of thermoclines Besides density as function of temperature is
used to evaluate the volume change in the process of freezing which contributes to potential
stress
Alkalialkaline nitrate salts were studied very much about their density as function of
temperature All the results indicate that the density was decreased linearly as temperature
increases and any specific density value in the molten state can be expressed by equation as
equation 4
= A-BT [4]
Where (gcm3) is the density of salt A (gcm
3) is the initial density value at 0
oC and B
(mgcm3degC) is the density change slope as function of temperature The coefficients are shown in
16
Table 25 for the nitrate group molten salts Among these systems pure sodium nitrate has the
largest value which reveals the high initial density value at low temperature [43] Conversely
lithium nitrate has the lowest value while it presents the smallest decrease trend as temperature
increases [44] The densities and A B values of multi-component nitrate salts were included in
the range of those two salts discussed above
Table 25 Density coefficients A and B of nitrate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiNO3 1922 0556
NaNO3 2334 0767
KNO3 2127 0760
NaNO3-KNO3 2134 0773
KNO3-CaNO3-LiNO3 2172 0735
LiNO3-KNO3-NaNO3 2083 0715
Several experiments were also conducted to measure the density as function of temperature
for the individual and multi-component carbonate salt systems The density of the carbonate salt
also follow the same trend as that of nitrate salt and the temperature dependence of density
followed the linear equation as discussed above It is observed that all the carbonate salts have
higher initial density coefficient A than the nitrate salt The largest value is reached to 2511 and
even the lowest value in this group is greater than the maximum A of nitrate group [45-49]
What‟s more the regression slope coefficient B of carbonate salt is lower compared to that of the
nitrate salt group Accordingly the salts in this group present larger density in the molten state
and the density coefficient A and B are given in Table 26
17
Table 26 Density coefficients A and B of carbonate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
Li2CO3 2303 0532
Na2CO3 2350 0448
Na2CO3-K2CO3 2473 0483
Li2CO3-K2CO3 2511 0599
Li2CO3-Na2CO3 2456 0519
Li2CO3-Na2CO3-K2CO3 2364 0544
Density of metal fluoride and chloride molten salt were also examined and present similar
regression trend as temperature increases The linear temperature dependence is also expressed
by the same equation On the basis of previous literature data the pure chloride salt shows lower
density than the fluoride salt with the same cation in the molten state [49] What‟s more the
sodium halide salt has the largest density value while the lithium halide salt has the lowest value
which is very similar to the nitrate group salt The density determination coefficient A and B are
given in Table27
Table 27 Density coefficients A and B of chloridefluoride salts
Compound A(gcm3) Btimes103(gcm
3degC)
LiCl 1766 0432
NaCl 1991 0543
KCl 1976 0583
LiF 2226 0490
NaF 2581 0636
KF 2469 0651
LiF-NaF 2520 0818
LiCl-NaF-KCl 2436 0742
LiF-NaF-MgF 2240 0701
18
The density measurement of hydroxide was not conducted as much as those three anion
groups discussed above Only few data of density is available for the alkali hydroxide salt when
added into other salt systems and temperature dependence also follows the linear regression
trend [32 41] The density determination coefficient A and B are given in Table 28
Table 28 Density coefficients A and B of molten salt mixture with hydroxide salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiCl-LiOH 16 0443
LiF-LiOH 165 0471
23 Heat capacity
In the heating process the temperature of solar energy storage molten salt is increase by
absorbing energy from the solar radiation Conversely the same amount of heat is released and
applied to heating system in the process of cooling Heat capacity is the amount of heat required
to increase the temperature of certain material by 1 oC and can be viewed as the directly relevant
parameter to the energy storage ability To some extent the large heat capacity assures the
efficiency of the application of solar energy storage materials
The heat capacity of alkalialkaline nitrate salt was investigated for both individual and
multi-component system in the previous literature To simplify the comparison only the heat
capacity value at 500oC is shown in all the following tables In the liquid state the heat capacity
increases with temperature following linear equation and the increasing slope is as small as 10-5
to 10-4
[50 51] Among those alkali nitrate salt systems lithium nitrate has the largest heat
19
capacity at 500oC while potassium nitrate presents the lowest value at that temperature In table
29 the heat capacity results at the selected temperature in literature are given
Table 29 Heat capacity of alkali nitrate salt at 500oC
Compound Heat capacity(JgK)
LiNO3 2175
NaNO3 1686
KNO3 1400
NaNO3-KNO3 1533
LiNO3-KNO3 1642
LiNO3-KNO3-NaNO3 1681
For the carbonate salt systems in the molten state the heat capacity is almost constant and
almost independent with temperature [32 33] Same as the nitrate group salts the heat capacity
for pure carbonate salt decreases as the atomic number of the alkali element increases which
means the value for lithium carbonate is the largest and that of potassium carbonate is the
smallest Generally the heat capacity value for carbonate in molten state is larger than that in
solid state However the sodium-potassium carbonate binary system is an exception for which
the heat capacity in solid state is larger than liquid state In table 210 the heat capacity results of
carbonate salts at the selected temperature in literature are given
Table 210 Heat capacity of alkali carbonate salt at 500oC
Compound Heat Capacity(JgK)
Li2CO3 250
Na2CO3 178
K2CO3 151
Na2CO3-K2CO3 157
20
Li2CO3-K2CO3 160
Li2CO3-Na2CO3 209
Li2CO3-K2CO3-Na2CO3 163
The heat capacity of fluoridechloride salt was measured in several literature and found
that for the pure salt the lithium halide has the biggest heat capacity data in the molten state
while the potassium halides shows the lowest heat capacity value Similar to the carbonate group
the heat capacity value of fluoridechloride salt varies little with temperature in the liquid state
[32 33] The values at 500oC for the alkalialkaline halides are shown in Table 211
Table 211 Heat capacity of fluoridechloride salt at 500oC
Compound Heat Capacity (JgK)
LiCl 148
NaCl 115
KCl 090
LiF-KF 163
NaCl-MgCl2 100
LiF-NaF-KF 155
KCl-MgCl2-CaCl2 092
The heat capacity of pure and multi-component hydroxide salt systems is limited in the
previous literature and the values in the liquid state follow linear equation which is observed for
all the molten salt discussed above [52] The values at 500oC for the alkalialkaline halides are
shown in Table 212
21
Table 212 Heat capacity of hydroxide salt at 500oC
Compound Heat Capacity(JgK)
NaOH 188
LiOH-NaOH 221
NaOH-KOH 182
In summary on the basis of comparison of various physic-chemical properties molten
nitrate slats have relatively low melting point excellent working temperature range reasonable
density and high heat capacity As the result of that molten nitrate salt is suitable to be applied as
the thermal energy storage fluid in the solar energy storage system
22
CHAPTER 3
OBJECTIVES
Based on review of previous literature data it is found that there are several disadvantages
such as the high melting point relatively low density value or poor heat capacity in liquid state
which limit the application of molten salt in certain groups in solar thermal energy storage
system Conversely alkalialkaline nitrate salt is considered as the suitable choice and proposed
as the thermal energy storage liquid for high temperature
Currently the used thermal energy storage liquid is NaNO3 (60mol)-KNO3 (40mol)
binary system (solar salt) which has the melting point at 221oC [30] Although the melting point
for this salt mixture is not the lowest it is still emphasized because of its low investment cost
However there are some drawbacks for this binary nitrate mixture The main disadvantage is
the high melting point In evenings or in winter the molten salt can easily freeze and block the
pipeline As a result of that some auxiliary cost should be added to overcome this problem and
the total investment will be increased
Development and synthesis of newer molten salt mixtures with freezing point lower than
those currently used for thermal energy storage applications is necessary for higher efficiency of
utilization of solar energy and getting rid of any unnecessary cost The approach to develop
lower freezing point molten salt mixtures is by the prediction of new eutectic mixtures and also
23
by the development of new nitrate compounds Besides these two most well known systems
several other mixtures were also studied Preliminary evaluation of several new molten salt flux
systems based on requirements for thermal energy storage systems mainly including freezing
point density heat capacity viscosity and thermal energy storage density The promising
candidate low melting point molten salt system should satisfy the requirements that eutectic
melting temperatures are lower than 220oC and the thermal energy storage densities are higher
than binary solar salt It is known that the melting point can be lowered by the addition of one or
more ABNO3 nitrate compounds where A and B are cations Consequently several multi-
component systems which have more constituent salts than solar salt were came up with and
studied with little fundamental data on the physic-chemical properties at the required operating
conditions available at present
In this thesis the new systems with simulated eutectic compositions were tested for their
experimental melting points heat capacities using the Differential Scanning Calorimetry (DSC)
technique which is considered to be the accurate instrument for thermodynamic data analysis
[53-59] Some significant thermodynamic properties such as heat capacity enthalpy and entropy
and Gibbs energy were calculated in the thesis to evaluate the energy change of the system in the
phase change process and the potential of being applied in the parabolic trough solar power plant
The energy density was obtained by using the experimental measured density and heat capacity
of the mixtures in molten state Finally 9 down-selected systems were present and discussed
24
CHAPTER 4
THERMODYNAMIC MODELING OF SALT SYSTEMS
41 Thermodynamic modeling
To lower the melting point of solar energy storage system multi-component system is
applicable Thermodynamic model was introduced to predict the eutectic temperature of salt
systems based on the Gibbs energies of fusion of individual salt and that of mixing of constituent
binary systems At the eutectic temperature the Gibbs energies in the liquid state and solid state
of salt are equal In thermodynamics Gibbs energy of fusion can be expressed by the equation
given as follows
G = H-TS [5]
Where H is the change of enthalpy of fusion and S is the change of entropy of fusion Equally
the entropy change of fusion can be expressed by differentiating G and the equation is given
[6]
It is known that the change in entropy can be expressed in terms of change in heat capacity in the
melting process as
[7]
25
If the change of heat capacity is assume to be independent of temperature the integral of
from Tm to T can be shown as
[8]
where Sm is the entropy of fusion at the melting point which is equal to Accordingly
Eq8 can be rewritten as
[9]
Substituting Eq 9 in Eq 6 and integrating the equation from Tm to T we get
[10]
Eq 10 illustrates that by using the change of heat capacity melting point and enthalpy of fusion
the Gibbs energy change at any temperature can be obtained
The standard Gibbs energy of fusion of a salt bdquo1‟ can be expressed in terms of the activity
of the salt as
[11]
where is the molar excess Gibbs energy and X1 is the molefraction of the salt bdquo1‟ Gibbs
energy of fusion at any give temperature T is expressed by Eq 7 in terms of its molefraction and
partial molar excess Gibbs energy
26
Take LiNO3-NaNO3-KNO3 as an example in which the integral molar excess Gibbs energy is
composed of the summation of the Gibbs energies of three constituent binary system and one
ternary The expression of the integral excess Gibbs energy is given by Eq12
[12]
Gibbs energies of the three constituent binary systems LiNO3-NaNO3 LiNO3-KNO3 and
NaNO3-KNO3 of the LiNO3-NaNO3-KNO3 ternary system are taken from the literature [48 49]
The Gibbs energies of mixing or the integral excess Gibbs energies of the three constituent
binary systems of the LiNO3-NaNO3-KNO3 ternary system are given below
LiNO3-NaNO3 Binary System
Jmol [13]
LiNO3-KNO3 Binary System
Jmol [14]
NaNO3-KNO3 Binary System
Jmol [15]
When assume the intergral excess Gibbs energy of to be zero the excess Gibbs energy in
the ternary system can be expressed by the summation of three constituent binary systems
[16]
27
Generally the partial molar excess Gibbs energies are reduced from the integral molar
excess Gibbs energy and can be expressed by the generalized equation for certain ldquomrdquo
component salt as
[17]
In the ternary system the i value equals to 12 and 3 and the partial molar excess Gibbs energy
of mixing for each component can be expressed as follows
[18]
[19]
[20]
Based on Eq 7 and the partial molar excess Gibbs energy of individual component the
Gibbs energy in the fusion can be expressed as Eq21- 23
[21]
[22]
[23]
42 Calculations
The fusion of the ternary salt system is defined by solutions of Eq 21-Eq 23 Newton-
Raphson method can be used to solve these three non-linear equations by linearizing the non-
linear equations using the Taylor series and truncating the series to first order derivatives
28
Consider the three non-linear functions F G and H in three variables x y and z The three
equations that are solved for the three variables are written as
F(x y z) = 0
G(x y z) = 0
H(x y z) = 0 [24]
The partial derivatives of the function F with respect to x y and z are given as
[25]
Similarly the partials derivatives can be expressed for the other two functions G and H
Newton-Raphson iterative method of solving the three equations in three variables
essentially deals with the solution of the incremental vector in the matrix equation given below
[26]
For the initial values of x y and z (say xi yi and zi) the right hand side vector contains the
values of the functions at the initial values (xi yi and zi) The 3times3 matrix on the left hand side
contains the partial derivatives of the functions with respect to the three variables at the initial
values Solutions of the matrix equation (Eq 26) result in the increments of the variables x y
and z The variables for the next iteration will then be xi + x yi + y and zi + z The
process of solving the matrix equation (Eq 26) is continued until the increments in the variables
x y and z is less than a very small quantity The iteration process is then said to be
29
converged and the values of the variables at convergence of the solution are the roots of the
system of the three fusion equations
The composition of LiNO3 NaNO3 and KNO3 and the eutectic temperature is solved by
using the Newton-Raphson iterative method Different from the data in previous literature the
eutectic temperature for the ternary is 116oC Besides the composition for each component is
also different from those published in literatures The new molten ternary system is composed of
2592 wt LiNO3 2001 wt NaNO3 and 5407 wt KNO3 The similar method is also applied
to other multi-component systems to determine the composition and eutectic temperature The
predicted melting points for new solar energy storage system are given Table41
Table 41 Calculated composition and melting point of multi-component molten salts systems
System Composition (wt) Calc Tmp
LiNO3 NaNO3 KNO3 NaNO2 KNO2 Mg(NO3)2 MgKN (degC)
Salt 1 259 20 541 - - - - 116
Salt 2 - 161 547 292 - - - 1238
Salt 3 175 142 505 178 - - - 986
Salt 4 115 104 274 - - - 507 986
Salt 5 172 139 476 172 41 - - 957
Salt 6 9 423 336 - 151 - - 1000
Salt 7 193 - 546 237 24 - - 1081
Salt 8 193 - 559 239 - 09 - 1008
Salt 9 154 172 324 - - 83 267 1036
30
CHAPTER 5
EXPERIMENTAL PROCEDURE
51 Melting point determination of molten salt mixtures
511 Materials
Ternary quaternary and quinary nirate and nitrite mixtures were tested in the thesis Most
components in the mixtures don‟t require any pre-preparation and can be used as received The
only exception is new developed MgKN which was composed of 6667 mol KNO3 and 3333
mol Mg(NO3)2 This unique compound is synthesized from magnesium nitrate hexahydrate
(98 Alfa Aesar) and potassium nitrate (ACS 990 min Alfa Aesar) and added into the
mixture as one single component As received magnesium nitrate hexahydrate is dehydrated
before synthesizing MgKN compound Weighted amount of magnesium nitrate taken in a
stainless steel crucible and placed on a hot plate in an argon atmosphere Temperature of the salt
is measured with a thermocouple immersed in the salt The temperature was held at 52315 K for
2 hours The salt solidifies to a white mass The temperature of the salt is then raised to 57315 K
slowly to remove any traces of moisture and to ensure complete dehydration The complete
removal of water is ascertained by weight loss
512 Apparatus and Procedure
31
Differential scanning calorimetry (DSC) analysis was performed using Perkin Elmer
Diamond DSC instrument and the setup is shown in fig 51 Heat flow and temperature can be
recorded in the instrument with an accuracy of 00001 mW and 001 K respectively The
measurements were made under purified nitrogen atmosphere with a flow rate of 20ccmin and at
a heating rate of 5 Kmin
Fig 51 Photography of set-up for DSC equipment
After dehydration if necessary each component was weighed to an accuracy of 01mg with
the electrical balance and mixed thoroughly in a stainless steel crucible Later the mixture is
heated up to certain temperature at which the entire salt melts At this temperature the salt
mixture was held for about 30 minutes The salt mixture is allowed to air cool to ambient
temperature This procedure is repeated 3 to 4 times to get the well-mixed compound Standard
aluminum pan with lid used for DSC measurements are weighed before the experiment Small
amount of the synthesized compound is placed carefully in the aluminum pan and closed with
the lid The lid is crimped by a sample press and the pan is weighed The weight of the sample is
32
determined by removing the weight of the pan and lid For the determination of melting point
and heat capacity (20-25) mg of the sample was used
Perkin-Elmer Diamond Differential Scanning Calorimeter (DSC) is used to measure the
melting point and heat capacity of compound The crimped ample pan was immediately put
inside the sample chamber of DSC after preparation and held at 52315 K for 10 hours to remove
the trace amount of moisture possibly caught in the process of loading sample and also to ensure
a homogeneous mixture In the experimental procedure a temperature range from 29815 K to
52315 K was set with a heating rate of 5 K min
1 followed by a cooling cycle at the same rate
This cycle is repeated for at least 6 times to ensure good mixture of the sample and
reproducibility of the results
52 Heat Capacity determination of molten salt mixtures
To start Cp measurement the same procedure as that of melting point determination is
followed with an addition of bdquoiso-scan-iso‟ steps to the program after 5-cycle temperature scan
Starting from 29815 K the temperature was held for 5 minutes before and after each scan step
Small temperature scan range is chosen to avoid thermal resistance between device and testing
sample except when the temperature is approaching the melting temperature The upper limit for
the Cp measurement was set to 62315 K in our experiments Since the change in the molar heat
capacity of the salt in the liquid state is very small the Cp data in the liquid state can be easily fit
to an equation and extrapolated to higher temperatures To get the value of molar heat capacity
of the sample heat flow curve for the baseline of the empty sample pan also needs to be obtained
immediately following the identical ldquoiso-scan-isordquo steps which were used for the actual sample
33
run The difference of heat flow between the actual crimpled sample and the empty sample pan is
the absolute heat absorbed by the test sample
53 Density determination of molten salt mixtures
Density measurement was carried out with standard densitometer which has fixed volume
Initial weight of the densitometer is measured and noted Salt composition of which the density
is measured is placed in a beaker on a hot place The densitometer is also placed on the same hot
plate The temperature is set to a fixed value above the melting point of the salt and is measured
by a thermocouple After the salt is melted and when the temperature shows stable reading the
molten salt is poured in to the densitometer up to the set mark on the sensitometer bottle The
weight of the densitometer with the molten salt is measured The weight difference between this
weight and the weight of empty densitometer gives the weight of the molten salt at the fixed set
temperature By knowing the fixed volume in the densitometer the density of the salt at that
temperature can be calculated This procedure is repeated at least three times to accurately
determine the density of the salt
34
CHAPTER 6
RESULT AND DISCUSSION
61 Melting point determination
611 DSC equipment calibration
Before the actual melting point measurement pure indium zinc metal and several
individual salts were used to calibrate the DSC equipment For metals only one sharp peak was
observed for each and the heat flow curve for indium metal is shown in fig 61 However larger
and boarder peaks are found for salts just like the condition illustrated in fig 62 for pure
potassium nitrate Based on the results shown in Table 61 the experimental data for melting
points and enthalpies of fusion have excellent agreement with the literature values [60-63] The
variation of point is within 07 and the variation of change of enthalpy is less than 3
Figure 61 Melting point calibration with indium sample
35
Figure 62 Melting point calibration with KNO3 sample
Table 61 Calibration data of melting points with different samples
Sample
Lit
Tmp
Expt
Tmp
Lit
Ttrans
Expt
Ttrans
Lit
ΔHfusion
Expt
ΔHfusion
Lit
ΔHtrans
Expt
ΔHtrans
degC degC degC degC Jg Jg Jg Jg
Indium 1566 1563 - - 286 278 - -
Zinc 4195 4188 - - 1086 1068 - -
LiNO3 2567 2550 - - 3617 3633 - -
NaNO3 3100 3081 2770 2753 1777 1756 147 152
KNO3 3370 3372 1330 1332 993 1005 538 529
612 Results
Differential scanning calorimetry (DSC) was used to determine the melting point and any
solid state phase transitions of the salt mixture A low scanning rate was chosen to record the
heat flow curve as function of temperature in order to improve the sensitivity of detection [64] It
helps to pick up any small endothermic peaks and also avoids the thermal resistance between the
36
internal furnace and sample Nine systems were chosen to test and the eutectic composition is
already listed in Table 41
All the selected systems are composed of alkaline nitrate and nitrite and most of them have
three basic components which are lithium sodium potassium nitrate or nitrite All the quaternary
and quinary systems were developed on the basis of the LiNO3-NaNO3-KNO3 baseline ternary
Figure 63-611 shows the DSC plot of all the salt systems DSC plots for each system were
collected for at least five runs (each run with fresh salt preparation) to ensure the reproducibility
All the onset temperatures peak temperatures predicted temperatures enthalpy of fusion for
melting peaks and the solid phase transformation temperatures are given in Table62
Figure 63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt
37
Figure 64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt
Figure 65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt
38
Figure 66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt
Figure 67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt
39
Figure 68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
Figure 69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
40
Figure 610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt
Figure 611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN salt
Table 62 illustrates that the predicted melting point is close to the experimental
determined value and most deviation is within 10 except for system 9 The great agreement
41
between experimental and calculated data verifies the accuracy and feasibility of the
thermodynamic modeling
Table 62 DSC results of melting point transition point and predicted melting point
System Tmp Ttrans ΔHfusion
Calculated degC Onset degC Peak degC Peak degC Jg
Salt 1 1160 994 1191 1043 600
Salt 2 1238 1150 1240 NA 97
Salt 3 986 940 999 NA 244
Salt 4 986 940 1010 NA 60
Salt 5 957 910 950 NA 62
Salt 6 1000 930 960 NA 86
Salt 7 1081 992 1003 793 60
Salt 8 1008 1010 1019 853 59
Salt 9 1036 834 892 NA 93
613 Discussion
It is observed that the first curve is different from last ones shown in the DSC plots and
this phenomenon is common for all the melting point measurement with DSC technique This
happened because in the first cycle the moisture caught by salt mixture especially the lithium
nitrate was removed in the process of heating Moreover the partially solidified sample in the
sample loading process can be re-homogenized in the first heating cycle [65-67] In figure 63
69 and 610 more than one endothermic peak was found The first smaller endothermic peak
refers to solid state phase transition of the salt mixture The second larger endothermic peak
refers to the melting of the salt Normally the onset temperature of transition is taken as the
experimental transition point for any metallic sample However in case of molten salts mixtures
since the thermal conductivity is low [68-74] the complete transition is ensured only at the peak
42
transition temperature The thermal gradient which exists due to the low thermal conductivity of
the salt results in internal heat flow which enhances the mixing in the salt Thus the transition
temperature is defined as the peak temperature of phase transition For salt No1 the small
endothermic peak happened before and was connected to the main peak which occurred at
39027K The first endothermic peaks for salt No 7 and 8 occurred at almost the same
temperature because of the similar composition for these two compounds Since the small
amount of magnesium nitrate and potassium nitrite contained in these two compounds the small
endothermic peak can hardly be related to these two components Obviously the rest three major
components must have something to do with the first peaks happened before the melting peaks
for both cases Each component among the major three ones were tested to find out any possible
solid phase transition peaks of them and the results shown in Table 63 which reveals that
lithium nitrate doesnt have any phase transition peak in solid state while potassium nitrate and
sodium nitrite both own the solid phase transformation peaks before their melting peaks
Table 63 Fusion and solid phase transition temperature for individual salts
System Tmp degC Ttrans degC ΔHfusion Jg ΔHtrans Jg
LiNO3 2550 - 3633 -
KNO3 3372 1332 1005 529
NaNO2 4311 4170 1119 880
The further investigation was carried out by running the KNO3-NaNO2 (550 wt and 238 wt )
binary compound with the very similar weight percentage as that in salt No 7 (546 wt and
237 wt) and salt No 8 (559wt and 239wt) By converting the weight percentage of the
studied binary system into 100 scale the weight fraction for sodium nitrate and potassium
nitrate can be rewritten as 698wt and 302wt The DSC plot for this binary system was
43
shown in fig 612 Although the solid transition and melting temperature were brought down by
adding lithium nitrate the shape of the plots in fig 69 and 610 are identical to that shown in fig
612 The enthalpy of solid state transformation of the binary salt was also converted to that in
both quaternary systems by using the weight fraction occupied by the binary system and the
comparable change of converted enthalpy between the binary system and two quaternary systems
indicates the relevance of the solid transition peaks in salt 7 and 8 to the combined effect of
potassium nitrate and sodium nitrite
Figure 612 DSC plot of 698wt KNO3- 302wt NaNO2 binary system
The similar analysis was applied to No1 salt to find out the reason for the presence of a
small peak adherent to the main melting peak before the melting point Sodium nitrate and
potassium nitrate binary system was synthesized based on the weight fraction of these two
constituent salts in No 1 salt DSC plot for the sodium nitrate-potassium nitrate binary system in
Fig 613 with the converted composition which is essentially same as that in the No1 ternary
system shows smooth heat flow curve before the melting peak which means the solid transition
peak in ternary is not simply relative to the binary system Assumption was made that the solid
44
phase transformation peak in the ternary salt is resulted from a multiple effect ie the
combination of one of the eutectic binary system involved in the ternary salt mixture and the
other binary system which is composed of the rest components The statement is verified that the
small peak in salt 1 is mainly caused by the solid phase transformation peak in lithium nitrate-
potassium nitrate eutectic binary system given the similar shape of the DSC plots in Fig 614
Since in salt No1 there is excess amount of sodium nitrate to form the lithium nitrate-sodium
nitrate binary system the rest sodium nitrate can interact with potassium nitrate and form new
sodium-potassium nitrate system which is shown in fig615 Besides a solid phase
transformation peak is observed in fig615 which has a very small area and won‟t change the
shape of phase transformation peak in fig614 when these two binary systems are combined and
form salt 1 The enthalpies of solid state transformation in two binary salts were also converted
to that in salt 1 by using the weight fractions occupied by both binary systems The difference
of the change of converted enthalpies between the lithium-potassium nitrate eutectic binary and
ternary system is filled by the binary mixture which is composed of the rest components sodium
nitrate-potassium nitrate The comparable converted values of enthalpy change between salt 1
and its two constituent binary systems further verify the assumption that the solid phase
transformation happened in salt 1 is mainly due to the combined effect of LiNO3-KNO3 eutectic
binary system and NaNO3-KNO3 binary system
45
Figure613 DSC plot of 270wt NaNO3-730wt KNO3 binary system
Figure614 DSC plot of 458wtLiNO3-542wtKNO3 binary system
46
Figure615 DSC plot of 460wt NaNO3-540wt KNO3 binary system
Unlike those discussed mixtures above salt No2 Salt No4 Salt No5 and Salt No6 have
only one relatively board melting peak and the heat flow curve before and after are very stable
Similarly there is no solid transformation peaks observed in salt No3 salt No7 and salt No8
However the heat flow after the melting peak in these cases are not stable and the main
endothermic peak is followed by a small hump which is considered to be the recrystallization
process once the compound entered into the liquid state When the process is finished the heat
flow curve returns to steady state
Heating rate is a significant parameter when collect the heat flow curves by using DSC
technique Fig 616(a) and Fig 616(b) illustrate the difference of melting point for salt No6 due
to the change of heating rate If the heating rate is 20oCmin the peak temperature and onset
temperature for the melting peak is 9669oC and 9221
oC respectively Once the heating rate is
decreased to 5oCmin these two temperatures will also be lowered to 9614
oC and 9190
oC The
difference is resulted from the diverse amount of thermal resistance between the testing sample
and the furnace inside the DSC instrument [75] Under higher heating rate the decisive thermal
47
resistance is raised due to the low thermal conductivity medium between the furnace and the
actual sample The insensitivity of gas heat conduction medium in DSC results each unit of
temperature increase on one side cannot have an immediate response on the other side of the gas
Consequently the sample holder which is connected the furnace has a higher temperature than
that inside the sample In this condition the value of temperature profile collected as the sample
holder temperature is larger than the actual temperature The deviation will be much smaller
when the heating rate is reduced In the case the thermal resistance will be decreased because of
the lower temperature gradient of the gas medium in the heating process As a result of that the
collected temperature from the sensor attached to the sample holder will be very close to the
actual temperature inside the testing sample
Figure 616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 20oCmin
heating rate
48
Figure 616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 5oCmin
heating rate
Besides the difference of temperature while using higher and lower heat rate the solution
of DSC will also be affected by different heating rate Fig 617(a) shows the DSC plot for salt
No 7 using the heating rate as 5oCmin and the DSC plot in Fig 617(b) is collected under the
heating rate as 20oCmin It can be observed that in the lower heating rate two small separated
peaks can be viewed as two parts of the solid phase transformation process while in Fig 617(b)
two small peaks before the melting peak merge and present as a board hump The qualification
of resolution can be executed by the term named resolution factor RMKE which is calculated as
the ratio of the peak heat flow value of the separated peaks to that of the concave point between
two peaks The equation for determining RMIKE is given in Eq 27 [76 77]
RMIKE =hpeakhmin [27]
49
Figure 617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 5oCmin
heating rate
Figure 617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 20oCmin
heating rate
In the case of lower heating rate the RMKE is determined to be 15 and the value for higher
heating rate is not available because the concave point of heat flow doesn‟t exist from
Fig617(b) Since the higher RMKE value indicates better resolution it can be stated that the
50
lower heating rate also results in greater sensitivity of the equipment to pick up any small
endothermic peaks
Besides the down-selected 9 compounds some more salt mixtures were also tested Most
of them were not selected to the final candidate for the thermal energy storage application
because of their higher melting point Table 64 gives some of the trial systems measured with
DSC technique It is illustrated that the melting points of mixtures with lower or even no content
of lithium nitrate turn out to be higher than those with sufficient amount of lithium nitrate For
most of the mixtures with melting point lower than 120oC the amount of lithium nitrate should
be larger than 81wt Also all of the systems in table 64 with lithium nitrate less than 15wt
have melting point higher than 140oC Based on the observation above it is concluded that the
lithium nitrate can be used as an additive to bring the melting point down for thermal energy
storage systems
51
Table 64 Melting points of candidate systems as function of temperatures
System Composition (wt)
Onset
Temp
Peak
Temp
(oC) (
oC)
LiNO3 ndash NaNO3 ndash KNO2 107 459 434 890 910
LiNO3 - KNO3 - NaNO2 196 564 241
1024 1046
LiNO3 - NaNO3 - KNO3 - KNO2 90 423 337 151
930 960
LiNO3 - NaNO3 - NaNO2 - KNO2 81 454 65 401
900 910
LiNO3 - KNO3 - NaNO2 - KNO2 193 546 237 24
992 1003
LiNO3 - KNO3 - NaNO2 ndash Mg(NO3)2 193 559 238 09
1010 1020
LiNO3 - NaNO3 - KNO3 - Mg(NO3)2
- MgK 154 172 324 83 267 834 892
LiNO3 - NaNO3 - KNO2 ndash Ca(NO3)2 14 390 333 263
1250 1470
NaNO3 - KNO3 - NaNO2 - KNO2 425 163 71 341
1407 1447
NaNO3 - KNO3 - KNO2 ndash Mg(NO3)2 432 146 380 42
1386 1421
NaNO3 - NaNO2 - KNO2 - Ca(NO3)2 451 92 410 48
1150 1390
LiNO3 - NaNO3 - NaNO2 - KNO2 -
Ca(NO3)2 15 393 37 323 232 1380 1480
LiNO3 - NaNO3 - KNO2 - Ca(NO3)2 -
Mg(NO3)2 14 379 313 275 20 1339 1534
62 Heat capacity determination
621 Heat capacity calibration
DSC was also calibrated for the heat capacity measurement Lithium nitrate sodium
nitrate and potassium nitrate were examined for the heat capacities from room temperature to
upper limit temperature for the instrument In liquid state the heat capacity values for each salt
can be fit to straight line with trace amount of increasing trend Since the temperature range from
the onset temperature of liquid state to the upper limit of DSC is relatively small the heat
capacity values for pure individual salts can be viewed as constants The comparison between the
theoretical and experimental heat capacity data is given in Table 65 Except lithium nitrate the
52
experimental heat capacities data for the rest two systems are almost same as the literature Even
for lithium nitrate which demonstrates the biggest difference from the literature data the 28
vibration is still within a reasonable range
Table 65 Calibration data of heat capacities with different samples
Sample Lit Cp Expt Cp
JgK JgK
LiNO3 218 212
NaNO3 169 167
KNO3 140 139
622 Results
The materials used in the heat capacity measurements are the same as those in the melting
point experiments Molar heat capacities of the all compound were measured by the DSC
equipment from room temperature to 62315 K The heat flow is recorded as a function of
temperature in ldquoiso-scan-isordquo steps at intervals of 20 K The bdquoiso stage‟ refers to isothermal
holding at a particular temperature bdquoscan stage‟ refers to the heat flow recording at a heating rate
of 5 K min1
up to a an increment of 25 K followed by another isothermal holding stage This is
a standard procedure followed in the measurement of heat capacity of materials using the DSC
equipment [63 64] This procedure of heat capacity measurement has two advantages (i) any
heat fluctuations during the recording are avoided by the isothermal steps and (ii) any phase
transition can be highlighted by the choice of temperature range The absolute heat flow to the
sample is determined by subtracting the heat flow collected by running a baseline curve with an
empty pan Because the heat capacity measurement in the heating process corresponds to
53
collecting the value of required heat flow at each temperature all the heat capacity plots have the
same shape with that of heat flow in the melting point measurements Take the heat capacity plot
of LiNO3-NaNO3-KNO3 ternary system as an instance which is shown in fig 618 the heat
capacity curve also has two different peaks The first little peaks corresponds to one occurs at
39027K which was observed in fig 63 the second large and sharp peak happened right after the
small one is prevalent to the endothermic peak with the peak temperature as 39027 K Similarly
after the phase transformation the heat capacity in liquid state becomes very stable and increase
with temperature linearly with little slope
Fig 618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system as function of
temperature
The heat capacity change as function of temperature for salt No1 was illustrated in fig
619 Based on the trend of heat capacity in the liquid state any value for the system in the liquid
can be extrapolated The expressions for heat capacity in liquid state for the new molten salt
systems were discussed and given in the next sectionTable66 shows the specific heat capacity
54
of the all the selective compounds measured at 62315 K and extrapolated at 77315K Besides
the molar heat capacities at 77315K are given in Table 66 of all the salts
Fig 619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K
Table 66 Heat capacity of selected new TES molten salt mixtures
System Expt (62315K) Extrapolated(77315K) Extrapolated(77315K)
Cp JgK Cp JgK Molar Cp JmolK
Salt 1 153 170 1521
Salt 2 143 168 1515
Salt 3 148 155 2183
Salt 4 153 166 1411
Salt 5 153 170 1440
Salt 6 151 163 1435
Salt 7 156 167 1443
Salt 8 155 168 1410
Salt 9 161 170 1937
55
623 Thermodynamic properties
The standard thermodynamic properties such as entropy enthalpy and Gibbs energy for
salt mixtures are determined from the experimental data of melting point and heat capacity in the
temperature range of the present study and expression for determining these properties are given
in equation 28-30 In thermodynamics all these three properties are related to heat capacity and
its variances with temperature In the studied temperature range (29815K-62315K) they can be
described as expression includes heat capacity
[28]
[29]
[30]
Where Tt is the solid transformation temperature Tmp is the melting point ΔHt is enthalpy of
solid phase transformation and ΔHfusion is enthalpy of fusion The standard thermodynamic
properties entropy enthalpy and Gibbs energies as function of temperature for each compound
are expressed in the following section
6231 LiNO3-NaNO3-KNO3 (Salt 1)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3
compound (i) solid state 1 (32315-38415) K (ii) liquid state (40315-62315) K Accordingly
56
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62311 Heat capacity of solid state 1 (29815-38415) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the solid state 1 in the
temperature range of 29815 to 38415 K is fit to a second order polynomial equation Eqn (31)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[31]
( ) K
R2 = 0982
62312 Heat capacity of liquid state (40315-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a linear equation Eqn (32) gives the linear
equation along with the least square fit parameter (R2) in the temperature range for the liquid
state of the compound
JKmol [32]
57
R2 = 0947
Heat capacity data of the LiNO3-NaNO3-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62313 Thermodynamic properties of solid state 1(29815-38415) K
JKmol [33]
Jmol [34]
[35]
Jmol
62314 Thermodynamic properties of liquid state 2(40315-62315) K
[36]
58
JKmol
Jmol [37]
[38]
Jmol
Among the equations above equation (33)-(35) refer to the thermodynamic properties for
solid state equations (36)-(38) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature ranges for solid and liquid state are
given in Table A1 and A2 in appendix A respectively with the corresponding heat capacity as
function of temperature
6232 NaNO3-NaNO2-KNO3 (Salt 2)
The heat capacity data can be divided into two sections for NaNO3-NaNO2-KNO3
compound (i) solid state 1 (32315-39215) K (ii) liquid state (41315-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62321 Heat capacity of solid state 1 (29815-39215) K
59
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the solid state in the
temperature range of 29815 to 39215 K is fit to a second order polynomial equation Eqn (39)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[39]
( ) K
R2 = 0978
62322 Heat capacity of liquid state (40315-62315) K
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a second order polynomial equation Eqn (40)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[40]
R2 = 0941
60
Heat capacity data of the NaNO3-NaNO2-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62323 Thermodynamic properties of solid state 1(29815-39215) K
JKmol [41]
Jmol [42]
[43]
Jmol
62324 Thermodynamic properties of liquid state 2(40315-62315) K
JKmol [44]
61
Jmol [45]
[46]
Jmol
Among the equations above equation (41)-(43) refer to the thermodynamic properties for
solid state equations (44)-(46) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table B1 and B2 in appendix B respectively with the corresponding heat capacity as
function of temperature
6233 LiNO3-NaNO3 -KNO3-MgK (Salt 3)
The heat capacity data can be divided into two sections for LiNO3-NaNO3 -KNO3-MgK
compound (i) solid state 1 (29815-36415) K (ii) liquid state (42115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62331 Heat capacity of solid state 1 (29815-36415) K
62
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the solid state in the
temperature range of 29815 to 36415 K is fit to a second order polynomial equation Eqn (47)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[47]
( ) K
R2 = 0995
62332 Heat capacity of liquid state (42115-62315) K
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the liquid state in the
temperature range of 42115 to 62315 K is fit to a second order polynomial equation Eqn (48)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[48]
R2 = 0963
63
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
62333 Thermodynamic properties of solid state 1(29815-36415) K
JKmol [49]
Jmol [50]
[51]
Jmol
62334 Thermodynamic properties of liquid state 2(42115-62315) K
64
JKmol [52]
Jmol [53]
[54] [29]
Jmol
Among the equations above equation (49)-(51) refer to the thermodynamic properties for
solid state equations (52)-(54) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table C1and C2 in appendix C respectively with the corresponding heat capacity as
function of temperature
6234 LiNO3-NaNO3-KNO3-NaNO2 (Salt 4)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-NaNO2
compound (i) solid state 1 (29815-36315) K (ii) liquid state (38115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62341 Heat capacity of solid state 1 (29815-36315) K
65
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the solid state in the
temperature range of 29815 to 36315 K is fit to a second order polynomial equation Eqn (55)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[55]
( ) K
R2 = 0995
62342 Heat capacity of liquid state (38115-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the liquid state in the
temperature range of 38115 to 62315 K is fit to a second order polynomial equation Eqn (56)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[56]
R2 = 0972
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
66
62343 Thermodynamic properties of solid state 1(29815-36315) K
JKmol [57]
Jmol [58]
[59]
Jmol
62344 Thermodynamic properties of liquid state 2(38115-62315) K
JKmol [60]
Jmol [61]
67
[37]
Jmol [62]
Among the equations above equation (57)-(59) refer to the thermodynamic properties for
solid state equations (60)-(62) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table D1 and D2 in appendix D respectively with the corresponding heat capacity as
function of temperature
6235 LiNO3-NaNO3-NaNO2-KNO3-KNO2 (Salt 5)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-NaNO2-KNO3-
KNO2 compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62351 Heat capacity of solid state 1 (29815-35915) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
in the temperature range of 29815 to 35915 K is fit to a second order polynomial equation Eqn
(63) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
68
[63]
( ) K
R2 = 0996
62352 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the liquid
state in the temperature range of 37515 to 62315 K is fit to a second order polynomial equation
Eqn (64) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[64]
R2 = 0969
Heat capacity data of the LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62353 Thermodynamic properties of Solid state 1(29815-35915) K
JKmol [65]
69
Jmol [66]
[67]
Jmol
62354 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [68]
Jmol [69]
[45]
Jmol [70]
70
Among the equations above equation (65)-(67) refer to the thermodynamic properties for
solid state equations (68)-(70) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table E1 and E2 in appendix E respectively with the corresponding heat capacity as
function of temperature
6236 LiNO3-NaNO3-KNO3-KNO2 (Salt 6)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-KNO2
compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62361 Heat capacity of solid state 1 (29815-36515) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the solid state in the
temperature range of 29815 to 36515 K is fit to a second order polynomial equation Eqn (71)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[71]
( ) K
R2 = 0998
71
62362 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the liquid state in the
temperature range of 37515 to 62315 K is given in Table 20 The data is fit to a second order
polynomial equation Eqn (72) gives the linear equation along with the least square fit parameter
(R2) in the temperature range for the liquid state of the compound
[72]
R2 = 0953
Heat capacity data of the LiNO3-NaNO3-KNO3-KNO2 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62363 Thermodynamic properties of solid state 1(29815-35915) K
JKmol [73]
Jmol [74]
72
[75]
Jmol
62364 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [76]
Jmol [77]
Jmol [78]
Among the equations above equation (73)-(75) refer to the thermodynamic properties for
solid state equations (76)-(78) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
73
given in Table F1 and F2 in appendix F respectively with the corresponding heat capacity as
function of temperature
6237 LiNO3-KNO3-NaNO2-KNO2 (Salt 7)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62371 Heat capacity of solid state 1 (29815-35415) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 1 in
the temperature range of 29815 to 35415 K is fit to a second order polynomial equation Eqn
(79) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[79]
(29815-35415) K
R2 = 0993
62372 Heat capacity of solid state 2 (36215-37315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 2 in
the temperature range of 36215 to 37315 K is fit to a second order polynomial equation Eqn
74
(80) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 2 of the compound
[80]
R2 = 0977
62373 Heat capacity of liquid state (37915-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the liquid state in the
temperature range of 37915 to 62315 K is fit to a linear equation Eqn (81) gives the
polynomial equation along with the least square fit parameter (R2) in the temperature range for
the liquid state of the compound
[81]
R2 = 0961
Heat capacity data of the LiNO3-KNO3-NaNO2-KNO2 compound in the two solid states
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62374 Thermodynamic properties of solid state 1(29815-35415) K
75
JKmol [82]
Jmol [83]
[84]
Jmol
62375 Thermodynamic properties of solid state 2(36215-37315) K
JKmol [85]
Jmol [86]
76
[87] [62]
Jmol
62376 Thermodynamic properties of liquid state (37915-62315) K
JKmol [88]
Jmol [89]
Jmol [90]
Among the equations above equation (82)-(84) refer to the thermodynamic properties for
solid 1 equation (85)-(87) refer to the thermodynamic properties for solid 2 equations (88)-(90)
refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy values
77
in the studied temperature range for solid 1 solid 2 and liquid state are given in Table G1-G3 in
appendix G respectively with the corresponding heat capacity as function of temperature
6238 LiNO3-KNO3-NaNO2-Mg(NO3)2 (salt 8)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62381 Heat capacity of solid state 1 (29815-33715) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid
state 1 in the temperature range of 29815 to 33715 K is fit to a second order polynomial
equation Eqn (91) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the solid state 1 of the compound
[91]
(29815-33715) K
R2 = 0994
62382 Heat capacity of solid state 2 (36115-36415) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid state 2
in the temperature range of 36115 to 36415 K is given in Table 4 The data is fit to a second
78
order polynomial equation Eqn (92) gives the polynomial equation along with the least square
fit parameter (R2) in the temperature range for the solid state 2 of the compound
[92]
R2 = 0992
62383 Heat capacity of liquid state (41115-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the liquid state in
the temperature range of 41115 to 62315 K is given in Table 5 The data is fit to a linear
equation Eqn (93) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the liquid state of the compound
[93]
R2 = 0934
Heat capacity data of the LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the two solid
states follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62384 Solid state 1(29815-35415) K
79
JKmol [94]
Jmol [95]
[96]
Jmol
62385 Solid state 2(36115-36415) K
JKmol [97]
80
Jmol [98]
[99] [74]
Jmol
62386 Liquid state (41115-62315) K
JKmol [100]
Jmol [101]
Jmol [102]
Among the equations above equation (94)-(96) refer to the thermodynamic properties for
solid 1 equation (97)-(99) refer to the thermodynamic properties for solid 2 equations (100)-
(102) refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy
81
values in the studied temperature range for solid 1 solid 2 and liquid state are given in Table H1
and H2 in appendix H respectively with the corresponding heat capacity as function of
temperature
6239 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK(Salt 9)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-
Mg(NO3)2-MgK compound (i) solid state 1 (29815-35315) K (ii) liquid state (39115-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62391 Heat capacity of solid state 1 (29815-35315) K
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state in the temperature range of 29815 to 35315 K is fit to a second order polynomial equation
Eqn (103) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[103]
( ) K
R2 = 0996
62392 Heat capacity of liquid state (39115-62315) K
82
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the liquid
state in the temperature range of 39115 to 62315 K is fit to a second order polynomial equation
Eqn (104) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[104]
R2 = 0951
Heat capacity data of the LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62393 Solid state 1(29815-35315) K
JKmol [105]
Jmol [106]
83
[107]
Jmol
62394 Liquid state 2(39115-62315) K
JKmol [108]
Jmol [109]
[110]
Jmol
Among the equations above equation (105)-(107) refer to the thermodynamic properties
for solid state equations (108)-(110) refer to thermodynamic properties of the liquid The
entropy enthalpy and Gibbs energy values in the studied temperature range for solid and liquid
state are given in Table I1 and I2 in appendix I respectively with the corresponding heat
capacity as function of temperature
84
624 Discussion of Gibbs energy change for molten salts
The Gibbs energy change data as function of temperature for 9 systems are given in fig
620 and the values at 62315K are shown in Table 67 Every system demonstrates continuous
curve throughout the whole studied temperature range Most of systems have similar Gibbs
energy change values for each temperature spot due to the comparable compositions and
properties of constituent salts However salt 3 and salt 9 Both of these salts have certain
amount of MgKN compound which presents large absolute amount of change of Gibbs energy in
the same studied temperature range [66] Since the change of Gibbs energy for multi-component
mixture is relevant to that of each constituent salt the large absolute value of ΔG of MgKN
mainly contributes to the largely negative value of salt 3 and salt 9 shown in fig 620 Besides
it is observed that most systems contain nitrite salts present lower absolute value of Gibbs energy
change For example salt 1 doesn‟t include any nitrite salt and has a relatively high absolute
value of Gibbs energy change as 1704kJmol while other systems having nitrite salts show lower
value varies from 1372kJmol to 1592kJmol
85
Fig 620 Change of Gibbs energy as function of temperature for molten salt systems
Table 67 Change of Gibbs energy values at 62315K for molten salt systems
SNo System ΔG(kJmol)
1 LiNO3-NaNO3-KNO3 1704
2 NaNO3- NaNO2- KNO3 1372
3 LiNO3- NaNO3- KNO3- MgKN 2807
4 LiNO3- NaNO3- KNO3- NaNO2 1443
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1441
6 LiNO3-NaNO3-KNO3-KNO2 1570
7 LiNO3-KNO3-NaNO2-KNO2 1592
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1583
9 LiNO3-NaNO3-KNO3-Mg(NO3)2 -MgKN 2217
86
63 Density determination
631 Density calibration
Several pure molten salts are used to calibrate the density measurement set-up before the
actual density measurement All the density values decrease as function of temperature in the
liquid state and follow the same linear equations as described in eq 4 The experimental values
at 350oC for KNO3 NaNO3 and LiNO3 are selected to compare with the literature data at the
same temperature The results are shown in Table 68 Based on the comparison of the literature
data and the experimental data the variation of density for molten nitrate salt is within in 4
Table 68 Calibration of density measurements with different pure nitrate salts
Sample Literature density Experimental density
gcm3 gcm
3
LiNO3 1727 1701
NaNO3 2066 2144
KNO3 1860 1855
632 Results and discussions
The density result of the salt as function of temperature is plotted for all the salts in Figure
621 and Figure 622 It is observed that the temperature dependence of density above the
melting point is different from that in solid state As known in solid state the density of salt has
an exponential relation with temperature while in these liquid cases the density values have
linearly dependence with temperature The stable variation as function of temperature allows the
extrapolation of density at even higher temperature The regression analysis is performed to get
the coefficient used for describing eq 4 and the results for the coefficients are shown in
87
Table69 [78-80] It is observed that the change of composition is implied on the coefficient A
which indicates the initial point at 150oC The temperature dependence coefficient B doesn‟t
change much with composition which may be mainly affected by the group of anion and cation
Table 69 Coefficient A and B for density determination of salt 1-salt 9
Salt No System A Btimes10
3
(gcm3) (gcm
3degC)
1 LiNO3-NaNO3-KNO3 2032 0493
2 NaNO3- NaNO2- KNO3 2081 0570
3 LiNO3- NaNO3- KNO3-MgKN 2055 0526
4 LiNO3- NaNO3- KNO3- NaNO2 2033 0520
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 2018 0485
6 LiNO3-NaNO3-KNO3-KNO2 2060 0554
7 LiNO3-KNO3-NaNO2-KNO2 2048 0554
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 2044 0524
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 2060 0566
Figure 621 The densities of the salt 1-salt 5 as function of temperature
88
In figure 621 all the density values are clustered around 198gcm3 at 150
oC to
186gcm3 at high temperature end and the deviation of density between all the mixtures is within
in 0047g cm3 Among all the salt mixtures the NaNO3-NaNO2-KNO3 ternary system
demonstrates the highest density value throughout the studied temperature range and LiNO3-
NaNO3-KNO3 ternary system LiNO3- NaNO3-KNO3-NaNO2 quaternary system and LiNO3-
NaNO3-KNO3-NaNO2-KNO2 quinary system show densities at the bottom side of Fig 621 For
salt 2 which doesn‟t contain any lithium nitrate the density at every selected temperature spot
is obviously higher than that of salt 1 4 and 5 which have large amount of lithium nitrate
Moreover the salt 3 which contains the relatively small amount of lithium nitrate stays in
between of salt 1 and salt 2 This comparison illustrates that the addition of lithium nitrate has
an offsetting effect on density for molten salt and it is consistent with previous literature reports
[81] The four systems presented in figure 622 also show even closer density values in the
studied temperature range Similarly salt 6 which contains the least lithium nitrate has the
largest density Salt 7 and salt 8 have almost same composition for the three dominating
components as a result of that the density curves for both mixtures are determined by the same
regression coefficient A and B Moreover the larger amount of lithium nitrate involved in these
two salt mixtures contributes to the lower density given in figure622 which further verifies the
significantly offsetting effect of lithium nitrate on density
89
Figure 622 The densities of the salt 6-salt 9 as function of temperature
The salt mixtures with maximum and minimum amount of lithium nitrate were plotted and
compared with equimolar NaNO3-KNO3 binary system and pure KNO3 salt in Fig623 [82 83]
It is observed that the NaNO3-KNO3 binary system has very similar density value to that of salt
2 because of the analogous type and composition of component in both salts The density of
pure KNO3 is slightly lower than the binary salt mixture which indicates the density of NaNO3 is
close to but higher than KNO3 in the studied temperature range Salt 1 shows the lowest density
in Fig623 due to the offsetting effect on density caused by lithium nitrate which has been
discussed above
90
Figure 623 Density of the salt 1 salt 2 as function of temperature compared to the
equimolar NaNO3-KNO3 binary system and pure KNO3
64 Thermal energy storage density of molten salts
The energy density which is considered as one of the most significant parameters of TES
application can be evaluated by calculation based on the measured density heat capacity and
working temperature range The equation of the thermal energy storage density (E) at working
temperature of 500oC is expressed in equation 111
E = Cp (500-Tm) [111]
Where Cp and are extrapolated heat capacity and density at 500oC respectively Tm is
melting point for salt mixture The extrapolation of density and heat capacity is based on the
linear temperature dependence for both parameters in molten state and the values are shown in
Table 610
91
Table 610 Extrapolated value of density and heat capacity at 500oC of salt 1-salt 9
Salt
No System
Density Heat Capacity
(gmL) (JgK)
1 LiNO3-NaNO3-KNO3 1785 170
2 NaNO3- NaNO2- KNO3 1796 168
3 LiNO3-NaNO3-KNO3-MgK 1773 155
4 LiNO3- NaNO3- KNO3- NaNO2 1792 166
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1796 170
6 LiNO3-NaNO3-KNO3-KNO2 1783 163
7 LiNO3-KNO3-NaNO2-KNO2 1771 167
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1782 168
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 1777 170
The calculated energy density for each salt is given in Table 611 compared with that of
solar salt (NaNO3-KNO3) All the new synthesized salt mixtures have significantly higher energy
density than solar salt and salt 3 shows the highest energy density among the new salts
Although salt 1 has higher heat capacity and good melting point the energy density is still the
lowest among new salt mixtures given by the effect of low density The conclusion can be drawn
from these observations that the energy density is a property affected by multiple parameters and
every part plays an important role in determining the efficiency of energy storage of salt
mixtures
92
Table 611 Energy density of salt 1-salt 9 compare to solar salt
The gravimetric storage density of new molten salts are listed in Table 612 and compared
with those different storage systems in fig 624 It is found that in the parabolic trough working
temperature range the gravimetric storage densities of new molten salts are located on the higher
side Even though some reported sensible energy storage liquids have larger gravimetric density
values than the new salts the maximum working temperatures reveal the instable working
condition at 500oC Taking conversion efficiency thermal stability and gravimetric storage
density into considerations the new molten salts are the most suitable choices of the sensible
heat storage for parabolic trough application
Salt No System Energy Density
500degC (MJm3)
0 NaNO3- KNO3 756
1 LiNO3-NaNO3-KNO3 1162
2 NaNO3- NaNO2- KNO3 1135
3 LiNO3-NaNO
3-KNO
3-MgKN 1099
4 LiNO3- NaNO
3- KNO
3- NaNO
2 1189
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1232
6 LiNO3-NaNO3-KNO3-KNO2 1174
7 LiNO3-KNO3-NaNO2-KNO2 1183
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1192
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 1242
93
Fig 624 Gravimetric storage density comparison of different energy storage systems as
function of temperature
Table 612 Gravimetric storage densities for solar salt and new molten salts
Salt
No System
Gravimetric Storage Density
500degC (kJkg)
0 NaNO3- KNO3 404
1 LiNO3-NaNO3-KNO3 560
2 NaNO3- NaNO2- KNO3 533
3 LiNO3-NaNO
3-KNO
3-MgKN 575
4 LiNO3- NaNO
3- KNO
3- NaNO
2 612
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 595
6 LiNO3-NaNO3-KNO3-KNO2 594
7 LiNO3-KNO3-NaNO2-KNO2 604
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 610
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 649
94
CHAPTER 7
CONCLUSION
The melting points of new molten salts were experimentally determined using DSC
Different from metals the melting point was chosen as the peak temperature rather than onset
temperature of the endothermic peak due to the low thermal conductivity and broad phase
transition range of the molten nitride salt mixture All of the nine new molten salts have melting
points from 89oC to 124
oC which are much lower than current sodium-potassium binary solar
salt Some systems such as salt No1 No7 and No8 have solid phase transformation observed
from the DSC plots It is found that the phase transformations of salt No 7 and No 8 are mainly
contributed to the KNO3-NaNO2 binary system while the small solid transformation peak of salt
No1 is resulted from the combined effect of the KNO3-LiNO3 eutectic binary system involved in
the ternary salt and another binary system which is composed of the rest components The
heating rate of DSC was revealed as a significant parameter for the any endothermic peak
determination When using lower heating rate the thermal resistance between the studied sample
and the furnace will be minimal and the resolution of peak detection will be enhanced
The heat capacities of all the multi-component salts (1 to 9) were determined using DSC
and found varying from 143 to 161 JgK at 350oC The heat capacity in the liquid state
demonstrates linear increase trend as function of temperature On the basis of that the heat
capacity was extrapolated to parabolic trough operating temperature of 500oC Besides heat
capacity data as function of temperature are fit to polynomial equation and thermodynamic
95
properties like enthalpy entropy and Gibbs energies of the compound as function of temperature
are subsequently deduced
Experimental measurements of density of multi-component systems were conducted as
function of temperature in their liquid state In liquid state the density values decrease linearly
as temperature increases The results of those mixtures were compared to the solar salt and
individual constituent salts The comparison demonstrates that the addition of lithium nitrate
lowers the density which is consistent with the observation that lithium nitrate has the lowest
density among all the individual salts in the studied temperature range On the basis of densities
heat capacities and the melting points energy storage density for all the new salts were
calculated and compared to the binary solar salt Among all the new molten salt systems
LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN quinary system (salt 9) presents the largest thermal
energy storage density as well as the gravimetric density values Moreover the larger thermal
energy storage as well as gravimetric storage densities compared to the solar salt indicate the
better energy storage capacities of new salts for solar power generation systems
96
REFERENCES
[1] JF Manwell JG McGowan and AL Rogers Wind Energy Explained-Theory Design and
Application second edition John Wiley and sons Ltd UK 2009
[2] MJ Pasqualetti Morality space and the power of wind-energy landscapes Geographical
Review 90 2000 381-394
[3] DG Fink and HW Beaty Standard Handbook for Electrical Engineers Eleventh Edition
McGraw-Hill New York 1978
[4] R Bertani Geothermal Energy An Overview on Resources and Potential Proceedings of the
International Conference on National Development of Geothermal Energy Use 2009 Slovakia
[5] TA Volk LP Abrahamson EH White E Neuhauser E Gray C Demeter C Lindsey J
Jarnefeld DJ Aneshansley R Pellerin and S Edick Developing a Willow Biomass Crop
Enterprise for Bioenergy and Bioproducts in the United States Proceedings of Bioenergy
2000 October 15-19 2000 Buffalo New York USA
[6] M Asplund N Grevesse and AJ Sauval The new solar abundances-Part I the
observations Communications in Asteroseismology 147 2006 76-79
[7] DRWilliams Sun Fact Sheet NASA 2004
httpnssdcgsfcnasagovplanetaryfactsheetsunfacthtml
[8] U Herrmann Survey of Thermal Energy Storage for Parabolic Trough Power Plants Journal
of Solar Energy Engineering 124 2002 145-152
[9] Rocket Research Company Chemical energy storage for solar thermal conversion SAND79-
8198 Livermore Sandia National Laboratories 1979
97
[10] A Steinfeld and R Palumbo Solar thermochemical process technology Encyclopedia of
Physical Science and Technology 2001 237-256
[11] EA Fletcher Solar thermal processing a review Journal of Solar Energy Engineering
2001 63-74
[12] R W Bradshaw and Nathan P Siegel Molten Nitrate Salt Development for Thermal
Energy Storage in Parabolic Trough Solar Power Systems of the Energy Sustainability 2008
Conference August 10-14 2008 Jacksonville Florida USA
[13] B Kelly H Price D Brosseau and D Kearney Adopting NitrateNitrite Salt Mixtures as
the Heat Transport Fluid in Parabolic Trough Power Plants Proceedings of the Energy
Sustainability 2007 Conference June 27-30 2007 Long Beach CA
[14] H Reilly and G Kolb Evaluation of Molten Salt Power Tower Technology Based on
Experience at Solar Two SAND2001-3674 Sandia National Laboratories 2001
[15] T Wendelin ldquoParabolic Trough VSHOT Optical Characterization in 2005-2006rdquo NREL
wwwnrelgovdocsfy06osti40024pdf
[16] RB Diver C Andraka S Rawlinson V Goldberg and G Thomas The Advanced Dish
Development System Project ASME Proceedings of Solar Forum 2001 Washington DC
[17] S D Odeh G L Morrison and M Behnia Modelling of parabolic trough direct steam
generation solar collectors Solar Energy 62 1998 396-406
[18] V Heinzel H Kungle and M Simon Simulation of a parabolic trough collector ISES
Solar World Congress Harare Zimbabwe 1-10
[19] S D Odeh G L Morrison and M Behnia Modeling of Parabolic Trough Direct
Generation Solar Collectors Solar Energy 62 1998 395-406
[20] Ezzat Optimum Working Fluids for Solar Powered Rankine Cycle Cooling of Buildings
Solar energy 25 1980 235-241
98
[21] R G Reddy Ionic Liquids How well do we know them editorial Journal of Phase
Equilibria and Diffusion 27 2006 210-211
[22] M Zhang and R G Reddy Application of [C4min][Tf2N] Ionic Liquid as Thermal
Storage and Heat Transfer Fluids editor J Weidner ECS Transactions 2 (28) 2007 27-32
[23] M Zhang and R G Reddy Evaluation of Ionic Liquids as Heat Transfer Materials in
Thermal Storage Systems Energy Energy Materials editors F Dogan M Awano D Singh
and B Tuttle ASM International Materials Park Ohio USA MSampT‟07 2007 151-160
[24] R G Reddy Novel Applications of Ionic Liquids in Materials Processing Advanced
Structural and Functional Materials Design 2008 Journal of Physics Conference Series (JPCS)
165 2009 1-6
[25] RW Bradshaw and DE Meeker High-temperature stability of ternary nitrate molten
salts for solar thermal energy systems Solar Energy Materials 21 1990 51-60
[26] AS Trunin Designing and investigations of salt systems for solar energy utilization
Utilization of sun and other radiation sources in materials research Kiev Naukova Dumka 1983
p 228-38
[27] D J Rogers and G J Janz Melting-crystallization and premelting properties of sodium
nitrate-potassium nitrate Enthalpies and heat capacities Journal of Chemical and Engineering
Data 27 1982 424-428
[28] D Kearney U Herrmann P Nava and B Kelly Assessment of a molten salt heat transfer
fluid in a parabolic trough solar field Journal of Solar Energy Engineering 125 2003 170-176
[29] Q Peng J Ding X Wei J Yang and X Yang The preparation and properties of multi-
component molten salts Applied Energy 87 2010 2812-2817
[30] E M Levin C R Robbins and H F McMordie Phase Diagrams for Ceramists American
Ceramic Society 1964
[31] J C Oxley J L Smith E Rogers and M Yu Ammonium nitrate thermal stability and
explosivity modifiers Thermochimica Acta 384 2002 23-45
99
[32] LG Marianowski and HC Maru Latent heat thermal energy storage systems above
4508oC Proceedings of 12th intersociety energy conversion engineering conference 1977 55-
66
[33] HC Maru JF Dullea A Kardas L Paul LG Marianowski E Ong et al Molten salts
energy storage systems Chicago Final Report of the Institute of Gas Technology 1978
[34] WM Philips and JW Stears Advanced latent heat of fusion thermal energy storage for
solar power stations Proceedings of 20th intersociety energy conversion engineering conference
2 1985 384-391
[35] KE Mayo Heat source systems USA Patent 3605720 1971
[36] JI Eichelberger and HD Gillman Investigation of metal fluoride thermal energy storage
material Proceedings of 12th intersociety energy conversion engineering conference 1977 567-
574
[37] GR Heidenreich and MB Parekh Thermal energy storage for organic Rankine cycle solar
dynamic space power systems Proceedings of 21st intersociety energy conversion engineering
conference 2 1986 791-797
[38] IK Garkushin AC Trunin TT Miftakhov and MA Dibirov Salt heat storage
composition USSR Patent 1036734 1983
[39] W M Philips and J W Stears Advanced latent heat of fusion thermal energy storage for
solar power stations In Proceedings of 20th intersociety energy conversion engineering
conference 2 1985 384-391
[40] Y Takahashi M Kamimoto Y Abe R Sakamoto K Kanari and T Ozawa Investigation
of latent heat-thermal energy storage materials IV Thermoanalitical evaluation of binary eutectic
mixtures of NaOH with LiOH or KOH Thermochim Acta 121 1987 193-202
[41] C E Birchenall and A F Riechman Heat storage in eutectic alloys Metall Trans A
11A(8) 1980 1415-1420
100
[42] Y Takahashi R Sakamoto and M Kamimoto Heat capacities and latent heats of LiNO3
NaNO3 and KNO3 International Journal of Thermophysics 9(6) 1988 1081-1090
[43] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate Mixtures
Journal of Chemical Engineering Data 8(3) 1963 469
[44] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical Engineering Data 6 (4) 1961 493
[45] GF Petersen WA Ewing and G P Smith Densities of Some Salt Mixtures Journal of
Chemical Engineering Data 6 (4) 1961 540
[46] G J Janz and M R Lorenz Precise Measurement of Density and Surface Tension at
Temperatures up to 1000degC in One Apparatus Review of Scientific Instruments 31 (1) 1960
18-23
[47] G J Janz C B Allen N P Bansal R M Murphy and R P Tomkins Physical Properties
Data Compilations Relevant to Energy Storage II Molten Salts Data on Single and Multi-
Component Salt Systems National Bureau of Standards NSRDS-NBS 61 Part II April 1979
[48] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation Equations
for Critically Evaluated Density Surface Tension Electrical Conductance and Viscosity Data
Journal of Physical and Chemical Reference Data 17 1988 2
[49] A T Ward and G J Janz Molten Carbonate Electrolytes Electiral Conductance Density
and Surface Tension of Binary and Ternary Eleclrochimica Acta 10 1965 849-857
[50] Y Takahashi R Sakamoto and MKamimoto Heat Capacities and Latent Heat of LiNO3
NaNO3 amp KNO3 International Journal of Thermophysics 9 1998 1081-1090
[51] R W Carling Heat capacities of NaNO3 and KNO3 up to 800 K Thermochimica Acta 60
1983 265-275
[52] Y Takahashi Latent heat measurement by DSC with sapphire as standard material
Thermochim Acta 88(1) 1985 199-204
101
[53] GW Hohne W Hemminger and HJ Flammersheim Differential Scanning Calorimetry
Springer-Verlag Berlin 1996
[54] W Hemminger and G Hohne Calorimetry Fundamentals and Practice Verlag Weinheim
1984
[55] M Merzlyakov and C Schick Thermal conductivity from dynamic response of DSC
Thermochimica Acta 377 2001 183-191
[56] T Kousksou A Jamil S Gibout and Y Zeraouli Thermal analysis of phase change
emulsion Journal of Thermal Analysis and Calorimetry 96 2009 841-852
[57] A Jamil T Kousksou K El Omari Y Zeraouli and Y Le Guer Heat transfer in salt
solutions enclosed in DSC cells Thermochimica Acta 507-508 2010 15-20
[58] MJ Richardson Quantitative aspects of differential scanning calorimetry Thermochimica
Acta 300 1997 15-28
[59] S Rudtsch Uncertainty of heat capacity measurements with differential scanning
calorimeters Thermochimica Acta 382 2002 17-25
[60] M J Maeso and J Largo The phase diagram of LiNO3-NaNO3 and LiNO3-KNO3 the
behavior of liquid mixtures Thermochimica Acta 223 (1993) 145-156
[61] O J Kleppa A new twin high-temperature reaction calorimeter The heats of mixing in
liquid sodium-potassium nitrates Journal of Physical Chemistry 64(12) (1960) 1937-1940
[62] G W H Hhne H K Cammenga W Eysel E Gmelin and W Hemminger The
Temperature Calibration of Scanning Calorimeters Thermochimica Acta 160 1990 1-12
[63] L B Pankratz Thermodynamic Properties of Carbides Nitrides and Other Selected
Substances U S Bureau of Mines Bulletin 696 1994
[64] M Zhang and R G Reddy Thermodynamic properties of C4mim[Tf2N] ionic liquids 0 2
2010 71-76
102
[65] D Mantha T Wang and R G Reddy Thermodynamic Modeling of Eutectic Point in the
LiNO3-NaNO3-KNO3 Ternary System Journal of Phase Equilibria and Diffusion 2011
(accepted)
[66] R G Reddy T Wang and D Mantha Determination of thermodynamic properties of
2KNO3Mg(NO3)2 Thermochimica Acta 2011 (submitted)
[67] T Wang D Mantha and R G Reddy Thermal stability of new LiNO3-NaNO3-KNO3
ternary salt for thermal energy storage system (in preparation)
[68] G D Carvalho E Frollini and W N D Santos Thermal conductivity of polymers by hot-
wire method J Appl Poly Sci 62 (1996) 2281-2285
[69] H Bloom A Doroszkowski and S B Tricklebank Molten salt mixtures IX The thermal
conductivities of molten nitrate systems Aus J Chem 18(8) (1965) 1171-1176
[70] A G Turnbull Thermal conductivity of molten salts Aus J Appl Sci 12 (1961) 30-41
[71] L R White and H T Davis Thermal conductivity of molten alkali nitrates J Chem Phys
47(1967) 5433-5439
[72] M V Peralta-Martinez M J Assael M J Dix L Karagiannidis and W A Wakeham A
Novel Instrument for the Measurement of the Thermal Conductivity of Molten Metal Part1
Instrument‟s Description Int J Thermophysics 27 (2006) 353-375
[73] Y Tada M Harada M Tanlgakl and W Eguchl Laser Flash Method for Measuring
Thermal Conductivity of Liquids Application to Molten Salts Industrial and Engineering
Chemistry Fundamentals 20 1981 333- 336
[74] M V Smirnov V A Khokhlov and E S Filatov Thermal conductivity of molten alkali
halides and their mixtures Electrochimica Acta 32 (1986) 1019-1026
[75] E Marti E Kaisersberger and W D Emmerich NEW ASPECTS OF THERMAL
ANALYSIS Part I Resolution of DSC and means for its optimization Journal of Thermal
Analysis and Calorimetry 77 2004 905-934
103
[76] E Marti E Kaisersberger G Kaiser and WY Ma Netzsch Annual 2000
bdquoThermoanalytical Characterization of Pharmaceuticals‟ Netzsch-Geraumltebau GmbH D-95100
SelbBavaria
[77] P J van Ekeren C M Holl and A J Witteveen A comparative test of differential
scanning calorimeters Journal of Thermal Analysis and Calorimetry 49 1997 1105-1114
[78] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation
Equations for Critically Evaluated Density Surface Tension Electrical Conductance and
Viscosity Data Journal of Physical and Chemical Reference Data 17 1988 1
[79] G F Petersen W A Ewing and G P Smith ldquoDensities of Some Salt Mixturesrdquo Journal of
Chemical and Engineering Data 6 1961 540
[80] P M Nasch and S G Steinemann Density and Thermal Expansion of Molten Manganese
Iron Nickel Copper Aluminum and Tin by Means of the Gamma-Ray Attenuation Technique
Physics and Chemistry of Liquids 29 1995 43-58
[81] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical and Engineering Data 6 1961 493-496
[82] D A Nissen Thermophysical Properties of the Equimolar Mixture NaNO3-KNO3 from
300degC to 600degC Journal of Chemical and Engineering Data 27 1982 269-273
[83] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate
Mixtures Journal of Chemical and Engineering Data 8 1963 469
104
APPENDIX
Appendix A
Table A1 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in solid state
(29815-40315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 342 1290 417 -025
299 027 008 000 343 1317 426 -026
300 059 018 000 344 1345 436 -027
301 091 028 000 345 1372 445 -028
302 123 037 000 346 1399 455 -029
303 154 047 000 347 1427 464 -031
304 186 056 000 348 1454 474 -032
305 217 066 000 349 1481 483 -033
306 248 076 000 350 1508 493 -035
307 279 085 000 351 1535 503 -036
308 310 095 -001 352 1562 512 -038
309 340 104 -001 353 1589 522 -039
310 371 114 -001 354 1616 532 -041
311 401 123 -001 355 1643 541 -042
312 432 133 -002 356 1670 551 -044
313 462 142 -002 357 1697 561 -045
314 492 152 -002 358 1724 570 -047
315 521 161 -003 359 1751 580 -048
316 551 171 -003 360 1777 590 -050
317 581 180 -004 361 1804 600 -052
318 610 190 -004 362 1831 610 -053
319 640 199 -005 363 1858 619 -055
320 669 209 -005 364 1885 629 -057
105
321 698 218 -006 365 1911 639 -059
322 727 228 -007 366 1938 649 -060
323 756 237 -007 367 1965 659 -062
324 785 246 -008 368 1992 669 -064
325 814 256 -009 369 2018 679 -066
326 842 265 -009 370 2045 689 -068
327 871 275 -010 371 2072 699 -070
328 899 284 -011 372 2098 709 -072
329 928 294 -012 373 2125 719 -074
330 956 303 -012 374 2152 729 -076
331 984 313 -013 375 2179 739 -078
332 1012 322 -014 376 2205 750 -080
333 1041 331 -015 377 2232 760 -082
334 1069 341 -016 378 2259 770 -084
335 1096 350 -017 379 2286 780 -086
336 1124 360 -018 380 2312 791 -088
337 1152 369 -019 381 2339 801 -090
338 1180 379 -020 382 2366 811 -093
339 1207 388 -021 383 2393 822 -095
340 1235 398 -022 384 2420 832 -097
341 1263 407 -023 38415 2424 834 -097
Table A2 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in liquid state
(40315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
40315 4287 1565 -163 514 7070 2838 -796
404 4310 1575 -167 515 7094 2850 -803
405 4337 1585 -171 516 7117 2863 -810
406 4363 1596 -175 517 7141 2875 -817
407 4390 1607 -180 518 7165 2887 -824
408 4417 1618 -184 519 7188 2899 -831
409 4443 1629 -189 520 7212 2911 -839
410 4470 1640 -193 521 7235 2924 -846
411 4496 1651 -197 522 7259 2936 -853
412 4523 1662 -202 523 7282 2948 -860
106
413 4549 1672 -206 524 7306 2960 -868
414 4576 1683 -211 525 7329 2973 -875
415 4602 1694 -216 526 7352 2985 -882
416 4629 1705 -220 527 7376 2997 -890
417 4655 1716 -225 528 7399 3010 -897
418 4681 1727 -230 529 7422 3022 -904
419 4708 1738 -234 530 7446 3034 -912
420 4734 1749 -239 531 7469 3047 -919
421 4760 1760 -244 532 7492 3059 -927
422 4786 1771 -249 533 7516 3071 -934
423 4813 1782 -253 534 7539 3084 -942
424 4839 1793 -258 535 7562 3096 -949
425 4865 1804 -263 536 7585 3109 -957
426 4891 1816 -268 537 7608 3121 -965
427 4917 1827 -273 538 7632 3134 -972
428 4943 1838 -278 539 7655 3146 -980
429 4969 1849 -283 540 7678 3158 -988
430 4995 1860 -288 541 7701 3171 -995
431 5021 1871 -293 542 7724 3183 -1003
432 5046 1882 -298 543 7747 3196 -1011
433 5072 1894 -303 544 7770 3208 -1018
434 5098 1905 -308 545 7793 3221 -1026
435 5124 1916 -313 546 7816 3233 -1034
436 5149 1927 -318 547 7839 3246 -1042
437 5175 1938 -323 548 7862 3259 -1050
438 5201 1950 -328 549 7885 3271 -1058
439 5226 1961 -334 550 7908 3284 -1066
440 5252 1972 -339 551 7931 3296 -1073
441 5278 1983 -344 552 7953 3309 -1081
442 5303 1995 -349 553 7976 3322 -1089
443 5329 2006 -355 554 7999 3334 -1097
444 5354 2017 -360 555 8022 3347 -1105
445 5380 2028 -365 556 8045 3359 -1113
446 5405 2040 -371 557 8067 3372 -1121
447 5430 2051 -376 558 8090 3385 -1130
448 5456 2062 -382 559 8113 3398 -1138
449 5481 2074 -387 560 8136 3410 -1146
450 5506 2085 -393 561 8158 3423 -1154
451 5532 2097 -398 562 8181 3436 -1162
452 5557 2108 -404 563 8204 3448 -1170
107
453 5582 2119 -409 564 8226 3461 -1178
454 5607 2131 -415 565 8249 3474 -1187
455 5633 2142 -421 566 8271 3487 -1195
456 5658 2154 -426 567 8294 3499 -1203
457 5683 2165 -432 568 8317 3512 -1212
458 5708 2177 -438 569 8339 3525 -1220
459 5733 2188 -443 570 8362 3538 -1228
460 5758 2200 -449 571 8384 3551 -1237
461 5783 2211 -455 572 8407 3564 -1245
462 5808 2223 -461 573 8429 3576 -1253
463 5833 2234 -466 574 8452 3589 -1262
464 5858 2246 -472 575 8474 3602 -1270
465 5883 2257 -478 576 8496 3615 -1279
466 5907 2269 -484 577 8519 3628 -1287
467 5932 2280 -490 578 8541 3641 -1296
468 5957 2292 -496 579 8564 3654 -1304
469 5982 2304 -502 580 8586 3667 -1313
470 6007 2315 -508 581 8608 3680 -1322
471 6031 2327 -514 582 8631 3693 -1330
472 6056 2339 -520 583 8653 3706 -1339
473 6081 2350 -526 584 8675 3719 -1348
474 6105 2362 -532 585 8697 3732 -1356
475 6130 2373 -538 586 8720 3745 -1365
476 6155 2385 -544 587 8742 3758 -1374
477 6179 2397 -551 588 8764 3771 -1382
478 6204 2409 -557 589 8786 3784 -1391
479 6228 2420 -563 590 8808 3797 -1400
480 6253 2432 -569 591 8831 3810 -1409
481 6277 2444 -575 592 8853 3823 -1418
482 6301 2456 -582 593 8875 3836 -1426
483 6326 2467 -588 594 8897 3849 -1435
484 6350 2479 -594 595 8919 3863 -1444
485 6375 2491 -601 596 8941 3876 -1453
486 6399 2503 -607 597 8963 3889 -1462
487 6423 2515 -614 598 8985 3902 -1471
488 6448 2526 -620 599 9007 3915 -1480
489 6472 2538 -626 600 9029 3928 -1489
490 6496 2550 -633 601 9051 3942 -1498
491 6520 2562 -639 602 9073 3955 -1507
492 6544 2574 -646 603 9095 3968 -1516
108
493 6569 2586 -653 604 9117 3981 -1525
494 6593 2598 -659 605 9139 3994 -1535
495 6617 2610 -666 606 9161 4008 -1544
496 6641 2621 -672 607 9183 4021 -1553
497 6665 2633 -679 608 9205 4034 -1562
498 6689 2645 -686 609 9226 4048 -1571
499 6713 2657 -692 610 9248 4061 -1581
500 6737 2669 -699 611 9270 4074 -1590
501 6761 2681 -706 612 9292 4088 -1599
502 6785 2693 -713 613 9314 4101 -1608
503 6809 2705 -719 614 9335 4114 -1618
504 6833 2717 -726 615 9357 4128 -1627
505 6856 2729 -733 616 9379 4141 -1636
506 6880 2741 -740 617 9401 4154 -1646
507 6904 2754 -747 618 9422 4168 -1655
508 6928 2766 -754 619 9444 4181 -1665
509 6952 2778 -761 620 9466 4195 -1674
510 6975 2790 -768 621 9487 4208 -1684
511 6999 2802 -775 622 9509 4222 -1693
512 7023 2814 -782 623 9531 4235 -1703
513 7047 2826 -789 62315 9534 4237 -1704
109
Appendix B
Table B1 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(29815-39215K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 347 1233 382 -046
299 022 006 000 348 1258 390 -048
300 049 014 -001 349 1283 398 -049
301 075 022 -001 350 1307 406 -051
302 101 029 -001 351 1332 415 -053
303 127 037 -002 352 1356 423 -054
304 153 044 -002 353 1381 431 -056
305 179 052 -003 354 1405 440 -058
306 205 059 -003 355 1430 448 -060
307 230 067 -004 356 1455 456 -061
308 256 075 -004 357 1479 465 -063
309 282 082 -005 358 1504 473 -065
310 308 090 -005 359 1528 482 -067
311 333 098 -006 360 1553 490 -069
312 359 105 -007 361 1577 498 -071
313 384 113 -007 362 1602 507 -073
314 410 121 -008 363 1626 515 -075
315 435 128 -009 364 1651 524 -077
316 461 136 -010 365 1675 533 -079
317 486 144 -010 366 1700 541 -081
318 511 151 -011 367 1724 550 -083
319 537 159 -012 368 1749 558 -085
320 562 167 -013 369 1773 567 -087
321 587 175 -014 370 1798 576 -089
322 612 182 -015 371 1822 584 -092
323 637 190 -016 372 1847 593 -094
324 663 198 -017 373 1871 602 -096
325 688 206 -018 374 1896 611 -098
326 713 214 -019 375 1920 620 -100
327 738 222 -020 376 1945 628 -103
328 763 229 -021 377 1969 637 -105
329 788 237 -022 378 1994 646 -107
110
330 813 245 -023 379 2018 655 -110
331 838 253 -024 380 2043 664 -112
332 863 261 -025 381 2068 673 -115
333 887 269 -027 382 2092 682 -117
334 912 277 -028 383 2117 691 -120
335 937 285 -029 384 2141 700 -122
336 962 293 -030 385 2166 709 -125
337 987 301 -032 386 2191 718 -127
338 1011 309 -033 387 2215 727 -130
339 1036 317 -034 388 2240 737 -132
340 1061 325 -036 389 2265 746 -135
341 1086 333 -037 390 2289 755 -138
342 1110 341 -039 391 2314 764 -140
343 1135 349 -040 392 2339 774 -143
344 1160 357 -042 39215 2342 775 -144
345 1184 365 -043
Table B2 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(41315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
414 3280 1149 -209 520 5608 2235 -682
415 3302 1158 -212 521 5630 2246 -687
416 3325 1167 -216 522 5651 2257 -693
417 3348 1177 -219 523 5672 2268 -698
418 3370 1186 -223 524 5694 2279 -704
419 3393 1196 -226 525 5715 2290 -710
420 3416 1205 -229 526 5736 2302 -716
421 3438 1215 -233 527 5757 2313 -721
422 3461 1224 -236 528 5779 2324 -727
423 3483 1234 -240 529 5800 2335 -733
424 3506 1243 -243 530 5821 2347 -739
425 3529 1253 -247 531 5842 2358 -745
426 3551 1263 -250 532 5864 2369 -750
427 3574 1272 -254 533 5885 2380 -756
428 3596 1282 -257 534 5906 2392 -762
429 3619 1291 -261 535 5927 2403 -768
111
430 3641 1301 -265 536 5948 2414 -774
431 3663 1311 -268 537 5970 2426 -780
432 3686 1320 -272 538 5991 2437 -786
433 3708 1330 -276 539 6012 2449 -792
434 3731 1340 -279 540 6033 2460 -798
435 3753 1350 -283 541 6054 2471 -804
436 3775 1359 -287 542 6075 2483 -810
437 3798 1369 -291 543 6096 2494 -816
438 3820 1379 -294 544 6118 2506 -822
439 3842 1389 -298 545 6139 2517 -828
440 3865 1398 -302 546 6160 2529 -835
441 3887 1408 -306 547 6181 2540 -841
442 3909 1418 -310 548 6202 2552 -847
443 3932 1428 -314 549 6223 2563 -853
444 3954 1438 -318 550 6244 2575 -859
445 3976 1448 -322 551 6265 2586 -866
446 3998 1458 -326 552 6286 2598 -872
447 4021 1468 -330 553 6307 2610 -878
448 4043 1477 -334 554 6328 2621 -884
449 4065 1487 -338 555 6349 2633 -891
450 4087 1497 -342 556 6370 2645 -897
451 4109 1507 -346 557 6391 2656 -904
452 4131 1517 -350 558 6412 2668 -910
453 4154 1527 -354 559 6433 2680 -916
454 4176 1537 -358 560 6454 2691 -923
455 4198 1547 -363 561 6475 2703 -929
456 4220 1557 -367 562 6496 2715 -936
457 4242 1568 -371 563 6517 2727 -942
458 4264 1578 -375 564 6538 2738 -949
459 4286 1588 -380 565 6559 2750 -955
460 4308 1598 -384 566 6580 2762 -962
461 4330 1608 -388 567 6600 2774 -969
462 4352 1618 -393 568 6621 2786 -975
463 4374 1628 -397 569 6642 2798 -982
464 4396 1639 -401 570 6663 2810 -988
465 4418 1649 -406 571 6684 2821 -995
466 4440 1659 -410 572 6705 2833 -1002
467 4462 1669 -415 573 6726 2845 -1009
468 4484 1680 -419 574 6747 2857 -1015
469 4506 1690 -424 575 6767 2869 -1022
112
470 4528 1700 -428 576 6788 2881 -1029
471 4550 1710 -433 577 6809 2893 -1036
472 4572 1721 -437 578 6830 2905 -1042
473 4593 1731 -442 579 6851 2917 -1049
474 4615 1741 -446 580 6871 2929 -1056
475 4637 1752 -451 581 6892 2941 -1063
476 4659 1762 -456 582 6913 2953 -1070
477 4681 1773 -460 583 6934 2966 -1077
478 4703 1783 -465 584 6954 2978 -1084
479 4724 1793 -470 585 6975 2990 -1091
480 4746 1804 -474 586 6996 3002 -1098
481 4768 1814 -479 587 7017 3014 -1105
482 4790 1825 -484 588 7037 3026 -1112
483 4812 1835 -489 589 7058 3038 -1119
484 4833 1846 -494 590 7079 3051 -1126
485 4855 1856 -498 591 7100 3063 -1133
486 4877 1867 -503 592 7120 3075 -1140
487 4898 1877 -508 593 7141 3087 -1147
488 4920 1888 -513 594 7162 3100 -1154
489 4942 1899 -518 595 7182 3112 -1162
490 4963 1909 -523 596 7203 3124 -1169
491 4985 1920 -528 597 7224 3137 -1176
492 5007 1930 -533 598 7244 3149 -1183
493 5028 1941 -538 599 7265 3161 -1190
494 5050 1952 -543 600 7285 3174 -1198
495 5072 1962 -548 601 7306 3186 -1205
496 5093 1973 -553 602 7327 3198 -1212
497 5115 1984 -558 603 7347 3211 -1220
498 5136 1995 -563 604 7368 3223 -1227
499 5158 2005 -568 605 7389 3236 -1234
500 5180 2016 -574 606 7409 3248 -1242
501 5201 2027 -579 607 7430 3261 -1249
502 5223 2038 -584 608 7450 3273 -1257
503 5244 2049 -589 609 7471 3286 -1264
504 5266 2059 -595 610 7491 3298 -1272
505 5287 2070 -600 611 7512 3311 -1279
506 5309 2081 -605 612 7532 3323 -1287
507 5330 2092 -610 613 7553 3336 -1294
508 5352 2103 -616 614 7573 3348 -1302
509 5373 2114 -621 615 7594 3361 -1309
113
510 5394 2125 -627 616 7615 3374 -1317
511 5416 2136 -632 617 7635 3386 -1325
512 5437 2147 -637 618 7656 3399 -1332
513 5459 2158 -643 619 7676 3412 -1340
514 5480 2169 -648 620 7696 3424 -1348
515 5502 2180 -654 621 7717 3437 -1355
516 5523 2191 -659 622 7737 3450 -1363
517 5544 2202 -665 623 7758 3462 -1371
518 5566 2213 -670 62315 7761 3464 -1372
114
Appendix C
Table C1 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in solid
state (29815-36415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 333 1937 611 -034
299 048 014 000 334 1992 629 -036
300 104 031 000 335 2047 647 -038
301 160 048 000 336 2102 666 -040
302 216 065 000 337 2156 684 -042
303 272 082 -001 338 2211 703 -045
304 329 099 -001 339 2266 721 -047
305 385 116 -001 340 2321 740 -049
306 441 133 -002 341 2375 758 -052
307 496 150 -002 342 2430 777 -054
308 552 167 -003 343 2485 796 -056
309 608 185 -003 344 2539 815 -059
310 664 202 -004 345 2594 833 -062
311 720 219 -005 346 2648 852 -064
312 776 236 -006 347 2703 871 -067
313 831 254 -006 348 2757 890 -070
314 887 271 -007 349 2812 909 -072
315 942 289 -008 350 2866 928 -075
316 998 306 -009 351 2921 947 -078
317 1054 324 -010 352 2975 966 -081
318 1109 341 -011 353 3029 985 -084
319 1164 359 -012 354 3084 1004 -087
320 1220 377 -014 355 3138 1024 -090
321 1275 395 -015 356 3192 1043 -094
322 1331 412 -016 357 3246 1062 -097
323 1386 430 -018 358 3300 1082 -100
324 1441 448 -019 359 3355 1101 -103
325 1496 466 -020 360 3409 1120 -107
326 1552 484 -022 361 3463 1140 -110
327 1607 502 -024 362 3517 1159 -114
328 1662 520 -025 363 3571 1179 -117
329 1717 538 -027 364 3625 1199 -121
115
330 1772 556 -029 36415 3633 1202 -121
331 1827 574 -030
332 1882 593 -032
Table C2 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in liquid
state (42115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
42115 7428 2673 -455 523 11788 4725 -1440
422 7468 2690 -461 524 11827 4745 -1452
423 7515 2710 -468 525 11866 4766 -1464
424 7562 2730 -476 526 11904 4786 -1476
425 7608 2750 -484 527 11943 4807 -1488
426 7655 2770 -491 528 11982 4827 -1500
427 7702 2790 -499 529 12021 4847 -1512
428 7748 2810 -507 530 12059 4868 -1524
429 7795 2830 -514 531 12098 4888 -1536
430 7841 2849 -522 532 12137 4909 -1548
431 7887 2869 -530 533 12175 4929 -1560
432 7933 2889 -538 534 12213 4950 -1572
433 7979 2909 -546 535 12252 4970 -1584
434 8025 2929 -554 536 12290 4991 -1597
435 8071 2949 -562 537 12328 5011 -1609
436 8117 2969 -570 538 12366 5032 -1621
437 8163 2989 -578 539 12404 5052 -1634
438 8208 3009 -586 540 12442 5073 -1646
439 8254 3029 -595 541 12480 5093 -1659
440 8299 3049 -603 542 12518 5114 -1671
441 8345 3069 -611 543 12556 5134 -1684
442 8390 3089 -620 544 12594 5155 -1696
443 8435 3109 -628 545 12632 5175 -1709
444 8480 3129 -636 546 12669 5196 -1721
445 8525 3149 -645 547 12707 5217 -1734
446 8570 3169 -654 548 12745 5237 -1747
116
447 8615 3189 -662 549 12782 5258 -1760
448 8659 3209 -671 550 12820 5278 -1772
449 8704 3229 -679 551 12857 5299 -1785
450 8748 3249 -688 552 12894 5319 -1798
451 8793 3269 -697 553 12932 5340 -1811
452 8837 3289 -706 554 12969 5361 -1824
453 8881 3309 -715 555 13006 5381 -1837
454 8926 3329 -724 556 13043 5402 -1850
455 8970 3349 -732 557 13080 5422 -1863
456 9014 3369 -741 558 13117 5443 -1876
457 9058 3389 -750 559 13154 5464 -1889
458 9102 3409 -760 560 13191 5484 -1902
459 9145 3429 -769 561 13228 5505 -1916
460 9189 3449 -778 562 13264 5526 -1929
461 9233 3469 -787 563 13301 5546 -1942
462 9276 3489 -796 564 13338 5567 -1956
463 9319 3509 -806 565 13374 5588 -1969
464 9363 3529 -815 566 13411 5608 -1982
465 9406 3549 -824 567 13447 5629 -1996
466 9449 3570 -834 568 13484 5650 -2009
467 9492 3590 -843 569 13520 5670 -2023
468 9535 3610 -853 570 13557 5691 -2036
469 9578 3630 -862 571 13593 5712 -2050
470 9621 3650 -872 572 13629 5732 -2063
471 9664 3670 -882 573 13665 5753 -2077
472 9707 3690 -891 574 13701 5774 -2091
473 9749 3710 -901 575 13737 5795 -2104
474 9792 3731 -911 576 13773 5815 -2118
475 9834 3751 -921 577 13809 5836 -2132
476 9877 3771 -930 578 13845 5857 -2146
477 9919 3791 -940 579 13881 5877 -2160
478 9961 3811 -950 580 13917 5898 -2174
479 10004 3831 -960 581 13953 5919 -2188
480 10046 3852 -970 582 13988 5940 -2202
481 10088 3872 -980 583 14024 5960 -2216
482 10130 3892 -990 584 14060 5981 -2230
483 10171 3912 -1001 585 14095 6002 -2244
484 10213 3932 -1011 586 14131 6023 -2258
485 10255 3953 -1021 587 14166 6044 -2272
486 10297 3973 -1031 588 14201 6064 -2286
117
487 10338 3993 -1042 589 14237 6085 -2300
488 10380 4013 -1052 590 14272 6106 -2315
489 10421 4034 -1062 591 14307 6127 -2329
490 10462 4054 -1073 592 14342 6148 -2343
491 10504 4074 -1083 593 14378 6168 -2358
492 10545 4094 -1094 594 14413 6189 -2372
493 10586 4114 -1104 595 14448 6210 -2386
494 10627 4135 -1115 596 14483 6231 -2401
495 10668 4155 -1126 597 14518 6252 -2415
496 10709 4175 -1136 598 14552 6273 -2430
497 10750 4196 -1147 599 14587 6293 -2444
498 10791 4216 -1158 600 14622 6314 -2459
499 10831 4236 -1169 601 14657 6335 -2474
500 10872 4256 -1179 602 14692 6356 -2488
501 10912 4277 -1190 603 14726 6377 -2503
502 10953 4297 -1201 604 14761 6398 -2518
503 10993 4317 -1212 605 14795 6419 -2533
504 11034 4338 -1223 606 14830 6439 -2547
505 11074 4358 -1234 607 14864 6460 -2562
506 11114 4378 -1245 608 14899 6481 -2577
507 11154 4399 -1257 609 14933 6502 -2592
508 11194 4419 -1268 610 14967 6523 -2607
509 11234 4439 -1279 611 15002 6544 -2622
510 11274 4460 -1290 612 15036 6565 -2637
511 11314 4480 -1302 613 15070 6586 -2652
512 11354 4500 -1313 614 15104 6607 -2667
513 11394 4521 -1324 615 15138 6628 -2682
514 11433 4541 -1336 616 15172 6649 -2697
515 11473 4562 -1347 617 15206 6670 -2713
516 11513 4582 -1359 618 15240 6691 -2728
517 11552 4602 -1370 619 15274 6712 -2743
518 11591 4623 -1382 620 15308 6733 -2758
519 11631 4643 -1393 621 15342 6754 -2774
520 11670 4664 -1405 622 15375 6774 -2789
521 11709 4684 -1417 623 15409 6795 -2804
522 11748 4704 -1428 62315 15414 6799 -2807
118
Appendix D
Table D1 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in solid state
(29815-36315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
299 021 006 000 333 867 277 -012
300 047 014 000 334 891 285 -012
301 072 022 000 335 916 293 -013
302 097 029 000 336 940 302 -014
303 122 037 000 337 964 310 -015
304 147 045 000 338 989 318 -016
305 172 053 000 339 1013 327 -017
306 197 060 000 340 1037 335 -018
307 223 068 000 341 1061 343 -019
308 248 076 000 342 1085 352 -019
309 273 084 000 343 1109 360 -020
310 298 092 -001 344 1134 369 -021
311 323 099 -001 345 1158 377 -022
312 348 107 -001 346 1182 385 -024
313 373 115 -001 347 1206 394 -025
314 398 123 -002 348 1230 402 -026
315 423 131 -002 349 1254 411 -027
316 447 139 -002 350 1277 419 -028
317 472 147 -003 351 1301 428 -029
318 497 155 -003 352 1325 436 -030
319 522 163 -003 353 1349 445 -032
320 547 171 -004 354 1373 453 -033
321 572 179 -004 355 1396 462 -034
322 596 187 -005 356 1420 470 -035
323 621 195 -005 357 1444 479 -037
324 646 203 -006 358 1467 487 -038
325 670 211 -006 359 1491 496 -039
326 695 220 -007 360 1514 504 -041
327 720 228 -008 361 1538 513 -042
328 744 236 -008 362 1561 522 -043
329 769 244 -009 363 1584 530 -045
330 793 252 -010 36315 1588 532 -045
119
331 818 260 -010
Table D2 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in liquid
state (38115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
38115 2281 765 -104 503 5639 2242 -594
382 2307 775 -106 504 5664 2255 -600
383 2338 787 -109 505 5689 2267 -606
384 2369 798 -111 506 5713 2280 -611
385 2399 810 -113 507 5738 2292 -617
386 2430 822 -116 508 5763 2305 -623
387 2460 834 -118 509 5787 2317 -629
388 2491 846 -121 510 5812 2330 -634
389 2521 857 -123 511 5836 2342 -640
390 2551 869 -126 512 5861 2355 -646
391 2582 881 -128 513 5885 2367 -652
392 2612 893 -131 514 5910 2380 -658
393 2642 905 -134 515 5934 2392 -664
394 2672 917 -136 516 5959 2405 -670
395 2702 928 -139 517 5983 2417 -676
396 2732 940 -142 518 6007 2430 -682
397 2762 952 -144 519 6032 2443 -688
398 2792 964 -147 520 6056 2455 -694
399 2821 976 -150 521 6080 2468 -700
400 2851 988 -153 522 6104 2480 -706
401 2881 999 -156 523 6128 2493 -712
402 2910 1011 -159 524 6152 2506 -718
403 2940 1023 -162 525 6176 2518 -724
404 2969 1035 -164 526 6200 2531 -731
405 2999 1047 -167 527 6224 2544 -737
406 3028 1059 -170 528 6248 2556 -743
407 3057 1071 -174 529 6272 2569 -749
408 3087 1083 -177 530 6296 2581 -756
120
409 3116 1095 -180 531 6320 2594 -762
410 3145 1107 -183 532 6344 2607 -768
411 3174 1119 -186 533 6368 2619 -775
412 3203 1130 -189 534 6391 2632 -781
413 3232 1142 -192 535 6415 2645 -787
414 3261 1154 -196 536 6439 2657 -794
415 3290 1166 -199 537 6462 2670 -800
416 3319 1178 -202 538 6486 2683 -807
417 3347 1190 -206 539 6510 2696 -813
418 3376 1202 -209 540 6533 2708 -820
419 3405 1214 -212 541 6557 2721 -826
420 3433 1226 -216 542 6580 2734 -833
421 3462 1238 -219 543 6604 2746 -839
422 3490 1250 -223 544 6627 2759 -846
423 3519 1262 -226 545 6650 2772 -853
424 3547 1274 -230 546 6674 2785 -859
425 3575 1286 -233 547 6697 2797 -866
426 3604 1298 -237 548 6720 2810 -873
427 3632 1310 -240 549 6744 2823 -879
428 3660 1322 -244 550 6767 2836 -886
429 3688 1334 -248 551 6790 2848 -893
430 3716 1346 -251 552 6813 2861 -900
431 3744 1358 -255 553 6836 2874 -907
432 3772 1371 -259 554 6860 2887 -913
433 3800 1383 -263 555 6883 2900 -920
434 3828 1395 -267 556 6906 2912 -927
435 3856 1407 -270 557 6929 2925 -934
436 3883 1419 -274 558 6952 2938 -941
437 3911 1431 -278 559 6975 2951 -948
438 3939 1443 -282 560 6998 2964 -955
439 3966 1455 -286 561 7020 2976 -962
440 3994 1467 -290 562 7043 2989 -969
441 4021 1479 -294 563 7066 3002 -976
442 4049 1491 -298 564 7089 3015 -983
443 4076 1504 -302 565 7112 3028 -990
444 4103 1516 -306 566 7134 3041 -997
445 4131 1528 -310 567 7157 3054 -1005
446 4158 1540 -314 568 7180 3066 -1012
447 4185 1552 -319 569 7203 3079 -1019
448 4212 1564 -323 570 7225 3092 -1026
121
449 4240 1576 -327 571 7248 3105 -1033
450 4267 1589 -331 572 7270 3118 -1041
451 4294 1601 -336 573 7293 3131 -1048
452 4321 1613 -340 574 7315 3144 -1055
453 4347 1625 -344 575 7338 3157 -1063
454 4374 1637 -349 576 7360 3170 -1070
455 4401 1650 -353 577 7383 3183 -1077
456 4428 1662 -357 578 7405 3196 -1085
457 4455 1674 -362 579 7428 3208 -1092
458 4481 1686 -366 580 7450 3221 -1100
459 4508 1698 -371 581 7472 3234 -1107
460 4535 1711 -375 582 7494 3247 -1114
461 4561 1723 -380 583 7517 3260 -1122
462 4588 1735 -384 584 7539 3273 -1129
463 4614 1747 -389 585 7561 3286 -1137
464 4641 1760 -394 586 7583 3299 -1145
465 4667 1772 -398 587 7605 3312 -1152
466 4693 1784 -403 588 7628 3325 -1160
467 4720 1796 -408 589 7650 3338 -1167
468 4746 1809 -412 590 7672 3351 -1175
469 4772 1821 -417 591 7694 3364 -1183
470 4798 1833 -422 592 7716 3377 -1191
471 4825 1846 -427 593 7738 3390 -1198
472 4851 1858 -432 594 7760 3403 -1206
473 4877 1870 -437 595 7782 3416 -1214
474 4903 1882 -441 596 7804 3429 -1222
475 4929 1895 -446 597 7825 3442 -1229
476 4955 1907 -451 598 7847 3455 -1237
477 4980 1919 -456 599 7869 3469 -1245
478 5006 1932 -461 600 7891 3482 -1253
479 5032 1944 -466 601 7913 3495 -1261
480 5058 1956 -471 602 7934 3508 -1269
481 5083 1969 -476 603 7956 3521 -1277
482 5109 1981 -481 604 7978 3534 -1285
483 5135 1994 -487 605 8000 3547 -1293
484 5160 2006 -492 606 8021 3560 -1301
485 5186 2018 -497 607 8043 3573 -1309
486 5211 2031 -502 608 8064 3586 -1317
487 5237 2043 -507 609 8086 3599 -1325
488 5262 2055 -513 610 8107 3613 -1333
122
489 5288 2068 -518 611 8129 3626 -1341
490 5313 2080 -523 612 8150 3639 -1349
491 5338 2093 -528 613 8172 3652 -1357
492 5364 2105 -534 614 8193 3665 -1366
493 5389 2117 -539 615 8215 3678 -1374
494 5414 2130 -545 616 8236 3692 -1382
495 5439 2142 -550 617 8258 3705 -1390
496 5464 2155 -555 618 8279 3718 -1398
497 5489 2167 -561 619 8300 3731 -1407
498 5514 2180 -566 620 8321 3744 -1415
499 5539 2192 -572 621 8343 3757 -1423
500 5564 2205 -578 622 8364 3771 -1432
501 5589 2217 -583 623 8385 3784 -1441
502 5614 2230 -589 62315 8388 3786 -1443
123
Appendix E
Table E1 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in solid state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 913 287 -014
299 025 007 000 331 941 296 -015
300 054 016 000 332 970 306 -016
301 083 025 000 333 998 315 -017
302 112 034 000 334 1026 324 -018
303 141 042 000 335 1054 334 -019
304 170 051 000 336 1081 343 -020
305 199 060 -001 337 1109 353 -021
306 228 069 -001 338 1137 362 -022
307 257 078 -001 339 1165 371 -024
308 286 087 -001 340 1193 381 -025
309 315 096 -002 341 1221 390 -026
310 343 105 -002 342 1248 400 -027
311 372 113 -002 343 1276 409 -028
312 401 122 -003 344 1304 419 -030
313 430 131 -003 345 1331 428 -031
314 458 140 -003 346 1359 438 -032
315 487 149 -004 347 1386 447 -034
316 516 159 -004 348 1414 457 -035
317 544 168 -005 349 1441 466 -036
318 573 177 -006 350 1468 476 -038
319 602 186 -006 351 1496 486 -039
320 630 195 -007 352 1523 495 -041
321 659 204 -007 353 1550 505 -042
322 687 213 -008 354 1577 514 -044
323 715 222 -009 355 1605 524 -046
324 744 232 -009 356 1632 534 -047
325 772 241 -010 357 1659 543 -049
326 800 250 -011 358 1686 553 -050
327 829 259 -012 359 1713 563 -052
328 857 269 -013 35915 1717 564 -052
329 885 278 -013
124
Table E2 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in liquid state (376-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2323 777 -094 500 5525 2173 -590
376 2347 786 -096 501 5548 2184 -595
377 2375 797 -098 502 5572 2196 -601
378 2403 808 -101 503 5595 2208 -606
379 2431 818 -103 504 5619 2220 -612
380 2459 829 -106 505 5642 2232 -618
381 2487 839 -108 506 5665 2243 -623
382 2515 850 -111 507 5689 2255 -629
383 2542 861 -113 508 5712 2267 -635
384 2570 871 -116 509 5735 2279 -640
385 2598 882 -118 510 5759 2291 -646
386 2626 893 -121 511 5782 2303 -652
387 2653 903 -123 512 5805 2315 -658
388 2681 914 -126 513 5828 2326 -664
389 2708 925 -129 514 5852 2338 -669
390 2736 935 -132 515 5875 2350 -675
391 2763 946 -134 516 5898 2362 -681
392 2791 957 -137 517 5921 2374 -687
393 2818 968 -140 518 5944 2386 -693
394 2845 978 -143 519 5967 2398 -699
395 2873 989 -146 520 5990 2410 -705
396 2900 1000 -148 521 6013 2422 -711
397 2927 1011 -151 522 6036 2434 -717
398 2954 1022 -154 523 6059 2446 -723
399 2981 1032 -157 524 6082 2458 -729
400 3008 1043 -160 525 6105 2470 -735
401 3035 1054 -163 526 6128 2482 -741
402 3062 1065 -166 527 6151 2494 -747
403 3089 1076 -169 528 6173 2506 -754
404 3116 1086 -172 529 6196 2518 -760
405 3143 1097 -176 530 6219 2530 -766
125
406 3170 1108 -179 531 6242 2542 -772
407 3197 1119 -182 532 6265 2554 -778
408 3223 1130 -185 533 6287 2566 -785
409 3250 1141 -188 534 6310 2578 -791
410 3277 1152 -192 535 6333 2591 -797
411 3303 1163 -195 536 6355 2603 -804
412 3330 1174 -198 537 6378 2615 -810
413 3356 1185 -202 538 6400 2627 -816
414 3383 1195 -205 539 6423 2639 -823
415 3409 1206 -208 540 6445 2651 -829
416 3436 1217 -212 541 6468 2663 -836
417 3462 1228 -215 542 6490 2676 -842
418 3488 1239 -219 543 6513 2688 -849
419 3515 1250 -222 544 6535 2700 -855
420 3541 1261 -226 545 6558 2712 -862
421 3567 1272 -229 546 6580 2724 -868
422 3593 1283 -233 547 6602 2737 -875
423 3619 1294 -236 548 6625 2749 -882
424 3645 1305 -240 549 6647 2761 -888
425 3671 1317 -244 550 6669 2773 -895
426 3697 1328 -247 551 6692 2786 -902
427 3723 1339 -251 552 6714 2798 -908
428 3749 1350 -255 553 6736 2810 -915
429 3775 1361 -259 554 6758 2822 -922
430 3801 1372 -262 555 6780 2835 -929
431 3827 1383 -266 556 6803 2847 -935
432 3852 1394 -270 557 6825 2859 -942
433 3878 1405 -274 558 6847 2872 -949
434 3904 1416 -278 559 6869 2884 -956
435 3929 1428 -282 560 6891 2896 -963
436 3955 1439 -286 561 6913 2909 -970
437 3981 1450 -290 562 6935 2921 -977
438 4006 1461 -294 563 6957 2933 -983
439 4032 1472 -298 564 6979 2946 -990
440 4057 1483 -302 565 7001 2958 -997
441 4083 1495 -306 566 7023 2971 -1004
442 4108 1506 -310 567 7045 2983 -1011
443 4133 1517 -314 568 7067 2995 -1019
444 4159 1528 -318 569 7089 3008 -1026
445 4184 1540 -322 570 7110 3020 -1033
126
446 4209 1551 -327 571 7132 3033 -1040
447 4234 1562 -331 572 7154 3045 -1047
448 4260 1573 -335 573 7176 3058 -1054
449 4285 1585 -339 574 7198 3070 -1061
450 4310 1596 -344 575 7219 3083 -1069
451 4335 1607 -348 576 7241 3095 -1076
452 4360 1618 -352 577 7263 3108 -1083
453 4385 1630 -357 578 7284 3120 -1090
454 4410 1641 -361 579 7306 3133 -1098
455 4435 1652 -365 580 7328 3145 -1105
456 4460 1664 -370 581 7349 3158 -1112
457 4485 1675 -374 582 7371 3170 -1120
458 4510 1687 -379 583 7393 3183 -1127
459 4534 1698 -383 584 7414 3195 -1134
460 4559 1709 -388 585 7436 3208 -1142
461 4584 1721 -393 586 7457 3221 -1149
462 4609 1732 -397 587 7479 3233 -1157
463 4633 1743 -402 588 7500 3246 -1164
464 4658 1755 -406 589 7522 3258 -1172
465 4683 1766 -411 590 7543 3271 -1179
466 4707 1778 -416 591 7564 3284 -1187
467 4732 1789 -420 592 7586 3296 -1194
468 4756 1801 -425 593 7607 3309 -1202
469 4781 1812 -430 594 7628 3322 -1210
470 4805 1824 -435 595 7650 3334 -1217
471 4830 1835 -440 596 7671 3347 -1225
472 4854 1847 -444 597 7692 3360 -1233
473 4878 1858 -449 598 7714 3373 -1240
474 4903 1870 -454 599 7735 3385 -1248
475 4927 1881 -459 600 7756 3398 -1256
476 4951 1893 -464 601 7777 3411 -1264
477 4975 1904 -469 602 7799 3423 -1271
478 5000 1916 -474 603 7820 3436 -1279
479 5024 1927 -479 604 7841 3449 -1287
480 5048 1939 -484 605 7862 3462 -1295
481 5072 1951 -489 606 7883 3475 -1303
482 5096 1962 -494 607 7904 3487 -1311
483 5120 1974 -499 608 7925 3500 -1318
484 5144 1985 -504 609 7946 3513 -1326
485 5168 1997 -510 610 7967 3526 -1334
127
486 5192 2009 -515 611 7988 3539 -1342
487 5216 2020 -520 612 8009 3551 -1350
488 5240 2032 -525 613 8030 3564 -1358
489 5264 2044 -530 614 8051 3577 -1366
490 5288 2055 -536 615 8072 3590 -1374
491 5312 2067 -541 616 8093 3603 -1383
492 5335 2079 -546 617 8114 3616 -1391
493 5359 2090 -552 618 8135 3629 -1399
494 5383 2102 -557 619 8156 3642 -1407
495 5407 2114 -562 620 8177 3655 -1415
496 5430 2126 -568 621 8198 3667 -1423
497 5454 2137 -573 622 8219 3680 -1431
498 5478 2149 -579 623 8239 3693 -1440
499 5501 2161 -584 62315 8242 3695 -1441
128
Appendix F
Table F1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in solid
state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 1063 334 -017
299 029 009 000 331 1096 345 -018
300 063 019 000 332 1128 356 -019
301 097 029 000 333 1161 366 -020
302 131 039 000 334 1193 377 -021
303 165 050 000 335 1225 388 -022
304 199 060 -001 336 1258 399 -024
305 233 070 -001 337 1290 410 -025
306 267 081 -001 338 1322 421 -026
307 300 091 -001 339 1355 432 -028
308 334 101 -002 340 1387 443 -029
309 368 112 -002 341 1419 454 -030
310 401 122 -002 342 1451 464 -032
311 435 133 -003 343 1483 475 -033
312 468 143 -003 344 1515 486 -035
313 502 153 -004 345 1547 497 -036
314 535 164 -004 346 1578 508 -038
315 569 174 -005 347 1610 519 -039
316 602 185 -005 348 1642 531 -041
317 635 196 -006 349 1674 542 -043
318 668 206 -006 350 1705 553 -044
319 702 217 -007 351 1737 564 -046
320 735 227 -008 352 1769 575 -048
321 768 238 -009 353 1800 586 -049
322 801 248 -009 354 1832 597 -051
323 834 259 -010 355 1863 608 -053
324 867 270 -011 356 1894 619 -055
325 900 280 -012 357 1926 631 -057
326 932 291 -013 358 1957 642 -059
327 965 302 -014 359 1988 653 -061
328 998 313 -015 35915 1993 655 -061
329 1030 323 -016
129
Table F2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in liquid
state (37515-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2691 926 -083 500 6111 2416 -640
376 2717 936 -085 501 6136 2428 -646
377 2747 948 -088 502 6161 2440 -652
378 2778 959 -091 503 6185 2453 -658
379 2808 971 -094 504 6210 2465 -665
380 2838 982 -096 505 6235 2478 -671
381 2869 994 -099 506 6259 2490 -677
382 2899 1005 -102 507 6284 2502 -683
383 2929 1017 -105 508 6308 2515 -690
384 2959 1028 -108 509 6333 2527 -696
385 2989 1040 -111 510 6357 2540 -702
386 3019 1051 -114 511 6381 2552 -709
387 3049 1063 -117 512 6406 2565 -715
388 3079 1075 -120 513 6430 2577 -721
389 3109 1086 -123 514 6454 2590 -728
390 3138 1098 -126 515 6479 2602 -734
391 3168 1109 -129 516 6503 2615 -741
392 3198 1121 -133 517 6527 2627 -747
393 3227 1132 -136 518 6551 2640 -754
394 3257 1144 -139 519 6575 2652 -760
395 3286 1156 -142 520 6599 2665 -767
396 3316 1167 -146 521 6624 2677 -774
397 3345 1179 -149 522 6648 2690 -780
398 3374 1191 -152 523 6672 2702 -787
399 3403 1202 -156 524 6696 2715 -794
400 3433 1214 -159 525 6719 2727 -800
401 3462 1226 -163 526 6743 2740 -807
402 3491 1237 -166 527 6767 2753 -814
403 3520 1249 -170 528 6791 2765 -821
404 3549 1261 -173 529 6815 2778 -827
405 3578 1272 -177 530 6839 2790 -834
130
406 3606 1284 -180 531 6862 2803 -841
407 3635 1296 -184 532 6886 2815 -848
408 3664 1307 -187 533 6910 2828 -855
409 3693 1319 -191 534 6933 2841 -862
410 3721 1331 -195 535 6957 2853 -869
411 3750 1343 -199 536 6981 2866 -876
412 3778 1354 -202 537 7004 2879 -883
413 3807 1366 -206 538 7028 2891 -890
414 3835 1378 -210 539 7051 2904 -897
415 3864 1390 -214 540 7075 2917 -904
416 3892 1401 -218 541 7098 2929 -911
417 3920 1413 -222 542 7122 2942 -918
418 3948 1425 -226 543 7145 2955 -925
419 3977 1437 -230 544 7168 2967 -932
420 4005 1449 -234 545 7192 2980 -939
421 4033 1460 -238 546 7215 2993 -947
422 4061 1472 -242 547 7238 3005 -954
423 4089 1484 -246 548 7261 3018 -961
424 4117 1496 -250 549 7285 3031 -968
425 4145 1508 -254 550 7308 3044 -976
426 4172 1519 -258 551 7331 3056 -983
427 4200 1531 -262 552 7354 3069 -990
428 4228 1543 -266 553 7377 3082 -998
429 4256 1555 -271 554 7400 3095 -1005
430 4283 1567 -275 555 7423 3107 -1013
431 4311 1579 -279 556 7446 3120 -1020
432 4338 1591 -284 557 7469 3133 -1027
433 4366 1603 -288 558 7492 3146 -1035
434 4393 1614 -292 559 7515 3159 -1042
435 4421 1626 -297 560 7538 3171 -1050
436 4448 1638 -301 561 7561 3184 -1058
437 4475 1650 -306 562 7584 3197 -1065
438 4503 1662 -310 563 7607 3210 -1073
439 4530 1674 -315 564 7629 3223 -1080
440 4557 1686 -319 565 7652 3235 -1088
441 4584 1698 -324 566 7675 3248 -1096
442 4611 1710 -328 567 7697 3261 -1103
443 4638 1722 -333 568 7720 3274 -1111
444 4665 1734 -338 569 7743 3287 -1119
445 4692 1746 -342 570 7765 3300 -1126
131
446 4719 1758 -347 571 7788 3313 -1134
447 4746 1770 -352 572 7811 3326 -1142
448 4773 1782 -356 573 7833 3338 -1150
449 4800 1794 -361 574 7856 3351 -1158
450 4826 1806 -366 575 7878 3364 -1166
451 4853 1818 -371 576 7901 3377 -1173
452 4880 1830 -376 577 7923 3390 -1181
453 4906 1842 -381 578 7945 3403 -1189
454 4933 1854 -386 579 7968 3416 -1197
455 4959 1866 -391 580 7990 3429 -1205
456 4986 1878 -396 581 8012 3442 -1213
457 5012 1890 -401 582 8035 3455 -1221
458 5039 1902 -406 583 8057 3468 -1229
459 5065 1914 -411 584 8079 3481 -1237
460 5091 1926 -416 585 8101 3494 -1245
461 5118 1938 -421 586 8124 3507 -1254
462 5144 1951 -426 587 8146 3520 -1262
463 5170 1963 -431 588 8168 3533 -1270
464 5196 1975 -436 589 8190 3546 -1278
465 5222 1987 -441 590 8212 3559 -1286
466 5248 1999 -447 591 8234 3572 -1294
467 5274 2011 -452 592 8256 3585 -1303
468 5300 2023 -457 593 8278 3598 -1311
469 5326 2035 -463 594 8300 3611 -1319
470 5352 2048 -468 595 8322 3624 -1328
471 5378 2060 -473 596 8344 3637 -1336
472 5404 2072 -479 597 8366 3650 -1344
473 5430 2084 -484 598 8388 3663 -1353
474 5455 2096 -490 599 8410 3676 -1361
475 5481 2108 -495 600 8432 3690 -1369
476 5507 2121 -500 601 8454 3703 -1378
477 5532 2133 -506 602 8475 3716 -1386
478 5558 2145 -512 603 8497 3729 -1395
479 5583 2157 -517 604 8519 3742 -1403
480 5609 2170 -523 605 8541 3755 -1412
481 5634 2182 -528 606 8562 3768 -1420
482 5660 2194 -534 607 8584 3781 -1429
483 5685 2206 -540 608 8606 3795 -1438
484 5710 2219 -545 609 8627 3808 -1446
485 5736 2231 -551 610 8649 3821 -1455
132
486 5761 2243 -557 611 8670 3834 -1464
487 5786 2255 -563 612 8692 3847 -1472
488 5812 2268 -568 613 8713 3860 -1481
489 5837 2280 -574 614 8735 3874 -1490
490 5862 2292 -580 615 8756 3887 -1498
491 5887 2305 -586 616 8778 3900 -1507
492 5912 2317 -592 617 8799 3913 -1516
493 5937 2329 -598 618 8821 3926 -1525
494 5962 2342 -604 619 8842 3940 -1534
495 5987 2354 -610 620 8864 3953 -1542
496 6012 2366 -616 621 8885 3966 -1551
497 6037 2379 -622 622 8906 3979 -1560
498 6062 2391 -628 623 8928 3993 -1569
499 6086 2403 -634 62315 8931 3995 -1570
133
Appendix G
Table G1 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid I state (29815-33715K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 319 578 162 -004
299 024 000 000 320 606 170 -005
300 052 000 000 321 633 179 -005
301 080 007 000 322 660 188 -006
302 108 016 000 323 688 197 -007
303 136 024 000 324 715 205 -007
304 164 032 000 325 742 214 -008
305 192 041 000 326 769 223 -009
306 219 049 000 327 796 232 -009
307 247 058 000 328 823 241 -010
308 275 067 -001 329 851 250 -011
309 303 075 -001 330 878 259 -011
310 330 084 -001 331 905 268 -012
311 358 092 -001 332 932 277 -013
312 386 101 -002 333 959 285 -014
313 413 109 -002 334 985 294 -015
314 441 118 -002 335 1012 303 -016
315 468 127 -003 336 1039 312 -017
316 496 135 -003 337 1066 321 -018
317 523 144 -003 33715 1070 331 -019
318 551 153 -004
Table G2 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid II state (36115-36415K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36115 2433 825 -054
134
362 2454 832 -056
363 2478 841 -059
364 2503 850 -061
36415 2506 851 -062
Table G3 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
liquid state (41115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
41115 3833 1366 -210 518 6604 2649 -772
412 3857 1376 -213 519 6628 2661 -778
413 3885 1387 -217 520 6652 2674 -785
414 3913 1399 -221 521 6675 2686 -792
415 3941 1411 -225 522 6699 2699 -798
416 3969 1422 -229 523 6723 2711 -805
417 3997 1434 -233 524 6747 2723 -812
418 4025 1446 -237 525 6770 2736 -819
419 4053 1457 -241 526 6794 2748 -825
420 4081 1469 -245 527 6818 2761 -832
421 4109 1481 -249 528 6841 2773 -839
422 4137 1493 -253 529 6865 2786 -846
423 4165 1504 -257 530 6888 2798 -853
424 4192 1516 -262 531 6912 2810 -860
425 4220 1528 -266 532 6935 2823 -867
426 4248 1539 -270 533 6959 2835 -873
427 4275 1551 -274 534 6982 2848 -880
428 4303 1563 -279 535 7005 2860 -887
429 4330 1575 -283 536 7029 2873 -894
430 4358 1587 -287 537 7052 2885 -902
431 4385 1598 -292 538 7075 2898 -909
432 4412 1610 -296 539 7098 2910 -916
433 4439 1622 -300 540 7122 2923 -923
434 4467 1634 -305 541 7145 2935 -930
135
435 4494 1646 -309 542 7168 2948 -937
436 4521 1657 -314 543 7191 2960 -944
437 4548 1669 -318 544 7214 2973 -951
438 4575 1681 -323 545 7237 2986 -959
439 4602 1693 -328 546 7260 2998 -966
440 4629 1705 -332 547 7283 3011 -973
441 4656 1716 -337 548 7306 3023 -980
442 4683 1728 -341 549 7329 3036 -988
443 4710 1740 -346 550 7352 3048 -995
444 4736 1752 -351 551 7375 3061 -1003
445 4763 1764 -356 552 7398 3074 -1010
446 4790 1776 -360 553 7420 3086 -1017
447 4816 1788 -365 554 7443 3099 -1025
448 4843 1800 -370 555 7466 3111 -1032
449 4869 1812 -375 556 7489 3124 -1040
450 4896 1823 -380 557 7511 3137 -1047
451 4922 1835 -385 558 7534 3149 -1055
452 4949 1847 -390 559 7557 3162 -1062
453 4975 1859 -395 560 7579 3175 -1070
454 5002 1871 -400 561 7602 3187 -1077
455 5028 1883 -405 562 7625 3200 -1085
456 5054 1895 -410 563 7647 3213 -1093
457 5080 1907 -415 564 7670 3225 -1100
458 5106 1919 -420 565 7692 3238 -1108
459 5132 1931 -425 566 7714 3251 -1116
460 5159 1943 -430 567 7737 3263 -1123
461 5185 1955 -435 568 7759 3276 -1131
462 5211 1967 -440 569 7782 3289 -1139
463 5236 1979 -446 570 7804 3302 -1147
464 5262 1991 -451 571 7826 3314 -1155
465 5288 2003 -456 572 7849 3327 -1162
466 5314 2015 -461 573 7871 3340 -1170
467 5340 2027 -467 574 7893 3352 -1178
468 5366 2039 -472 575 7915 3365 -1186
469 5391 2051 -478 576 7937 3378 -1194
470 5417 2063 -483 577 7960 3391 -1202
471 5442 2075 -488 578 7982 3404 -1210
472 5468 2087 -494 579 8004 3416 -1218
473 5494 2099 -499 580 8026 3429 -1226
474 5519 2111 -505 581 8048 3442 -1234
136
475 5545 2123 -510 582 8070 3455 -1242
476 5570 2135 -516 583 8092 3468 -1250
477 5595 2147 -521 584 8114 3480 -1258
478 5621 2160 -527 585 8136 3493 -1266
479 5646 2172 -533 586 8158 3506 -1274
480 5671 2184 -538 587 8180 3519 -1283
481 5696 2196 -544 588 8201 3532 -1291
482 5722 2208 -550 589 8223 3545 -1299
483 5747 2220 -555 590 8245 3557 -1307
484 5772 2232 -561 591 8267 3570 -1315
485 5797 2244 -567 592 8289 3583 -1324
486 5822 2257 -573 593 8310 3596 -1332
487 5847 2269 -579 594 8332 3609 -1340
488 5872 2281 -585 595 8354 3622 -1349
489 5897 2293 -590 596 8375 3635 -1357
490 5922 2305 -596 597 8397 3648 -1365
491 5947 2317 -602 598 8419 3660 -1374
492 5971 2330 -608 599 8440 3673 -1382
493 5996 2342 -614 600 8462 3686 -1391
494 6021 2354 -620 601 8483 3699 -1399
495 6046 2366 -626 602 8505 3712 -1408
496 6070 2379 -632 603 8526 3725 -1416
497 6095 2391 -638 604 8548 3738 -1425
498 6119 2403 -645 605 8569 3751 -1433
499 6144 2415 -651 606 8591 3764 -1442
500 6169 2427 -657 607 8612 3777 -1451
501 6193 2440 -663 608 8633 3790 -1459
502 6217 2452 -669 609 8655 3803 -1468
503 6242 2464 -675 610 8676 3816 -1476
504 6266 2477 -682 611 8697 3829 -1485
505 6291 2489 -688 612 8719 3842 -1494
506 6315 2501 -694 613 8740 3855 -1503
507 6339 2513 -701 614 8761 3868 -1511
508 6363 2526 -707 615 8782 3881 -1520
509 6388 2538 -713 616 8803 3894 -1529
510 6412 2550 -720 617 8825 3907 -1538
511 6436 2563 -726 618 8846 3920 -1547
512 6460 2575 -733 619 8867 3933 -1555
513 6484 2587 -739 620 8888 3946 -1564
514 6508 2600 -746 621 8909 3959 -1573
137
515 6532 2612 -752 622 8930 3972 -1582
516 6556 2624 -759 623 8951 3985 -1591
517 6580 2637 -765 62315 8954 3987 -1592
138
Appendix H
Table H1 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid I
state (29815-35415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 768 241 -011
299 023 007 000 328 794 249 -011
300 050 015 000 329 820 258 -012
301 077 023 000 330 846 266 -013
302 104 031 000 331 872 275 -014
303 131 039 000 332 898 284 -015
304 158 048 000 333 924 292 -016
305 185 056 -001 334 950 301 -016
306 212 064 -001 335 976 310 -017
307 239 072 -001 336 1002 318 -018
308 265 081 -001 337 1028 327 -019
309 292 089 -001 338 1053 336 -020
310 319 097 -002 339 1079 344 -021
311 345 105 -002 340 1105 353 -022
312 372 114 -002 341 1130 362 -024
313 399 122 -003 342 1156 371 -025
314 425 130 -003 343 1182 379 -026
315 452 139 -004 344 1207 388 -027
316 478 147 -004 345 1233 397 -028
317 505 156 -004 346 1258 406 -029
318 531 164 -005 347 1284 415 -031
319 558 172 -005 348 1309 424 -032
320 584 181 -006 349 1335 433 -033
321 611 189 -007 350 1360 441 -035
322 637 198 -007 351 1385 450 -036
323 663 206 -008 352 1411 459 -037
324 689 215 -008 353 1436 468 -039
325 716 223 -009 354 1461 477 -040
326 742 232 -010 35415 1465 478 -040
139
Table H2 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid 2
state (36215-37315K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36215 2387 777 -046
363 2408 809 -055
364 2432 817 -057
365 2457 826 -060
366 2481 835 -062
367 2506 843 -065
368 2530 852 -067
369 2555 861 -070
370 2579 870 -072
371 2604 879 -075
372 2628 888 -077
373 2653 898 -080
37315 2657 907 -083
Table H3 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in liquid
state (37915-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37915 2966 1025 -100 502 6174 2432 -667
380 2991 1034 -102 503 6198 2444 -674
381 3020 1045 -105 504 6222 2456 -680
382 3048 1056 -108 505 6246 2468 -686
383 3077 1067 -112 506 6270 2480 -692
384 3105 1078 -115 507 6294 2492 -699
385 3134 1089 -118 508 6317 2504 -705
386 3162 1100 -121 509 6341 2516 -711
387 3191 1111 -124 510 6365 2528 -718
140
388 3219 1122 -127 511 6388 2541 -724
389 3247 1133 -130 512 6412 2553 -730
390 3275 1144 -134 513 6436 2565 -737
391 3304 1155 -137 514 6459 2577 -743
392 3332 1166 -140 515 6483 2589 -750
393 3360 1177 -144 516 6506 2601 -756
394 3388 1188 -147 517 6530 2613 -763
395 3416 1199 -150 518 6553 2625 -769
396 3444 1210 -154 519 6577 2638 -776
397 3472 1221 -157 520 6600 2650 -782
398 3500 1232 -161 521 6624 2662 -789
399 3527 1243 -164 522 6647 2674 -796
400 3555 1254 -168 523 6670 2686 -802
401 3583 1265 -171 524 6694 2698 -809
402 3611 1276 -175 525 6717 2711 -816
403 3638 1287 -179 526 6740 2723 -822
404 3666 1299 -182 527 6763 2735 -829
405 3693 1310 -186 528 6786 2747 -836
406 3721 1321 -190 529 6810 2760 -843
407 3748 1332 -193 530 6833 2772 -850
408 3776 1343 -197 531 6856 2784 -856
409 3803 1354 -201 532 6879 2796 -863
410 3830 1366 -205 533 6902 2809 -870
411 3857 1377 -209 534 6925 2821 -877
412 3885 1388 -213 535 6948 2833 -884
413 3912 1399 -216 536 6971 2845 -891
414 3939 1410 -220 537 6994 2858 -898
415 3966 1422 -224 538 7017 2870 -905
416 3993 1433 -228 539 7040 2882 -912
417 4020 1444 -232 540 7063 2895 -919
418 4047 1455 -236 541 7086 2907 -926
419 4074 1467 -240 542 7108 2919 -933
420 4101 1478 -245 543 7131 2932 -940
421 4128 1489 -249 544 7154 2944 -947
422 4154 1500 -253 545 7177 2957 -955
423 4181 1512 -257 546 7199 2969 -962
424 4208 1523 -261 547 7222 2981 -969
425 4234 1534 -265 548 7245 2994 -976
426 4261 1546 -270 549 7267 3006 -984
427 4288 1557 -274 550 7290 3019 -991
141
428 4314 1568 -278 551 7313 3031 -998
429 4341 1580 -282 552 7335 3044 -1005
430 4367 1591 -287 553 7358 3056 -1013
431 4393 1602 -291 554 7380 3068 -1020
432 4420 1614 -296 555 7403 3081 -1028
433 4446 1625 -300 556 7425 3093 -1035
434 4472 1636 -305 557 7448 3106 -1042
435 4499 1648 -309 558 7470 3118 -1050
436 4525 1659 -314 559 7492 3131 -1057
437 4551 1671 -318 560 7515 3143 -1065
438 4577 1682 -323 561 7537 3156 -1072
439 4603 1694 -327 562 7560 3169 -1080
440 4629 1705 -332 563 7582 3181 -1087
441 4655 1716 -336 564 7604 3194 -1095
442 4681 1728 -341 565 7626 3206 -1103
443 4707 1739 -346 566 7649 3219 -1110
444 4733 1751 -351 567 7671 3231 -1118
445 4759 1762 -355 568 7693 3244 -1126
446 4785 1774 -360 569 7715 3257 -1133
447 4810 1785 -365 570 7737 3269 -1141
448 4836 1797 -370 571 7759 3282 -1149
449 4862 1808 -375 572 7782 3294 -1157
450 4888 1820 -379 573 7804 3307 -1164
451 4913 1832 -384 574 7826 3320 -1172
452 4939 1843 -389 575 7848 3332 -1180
453 4964 1855 -394 576 7870 3345 -1188
454 4990 1866 -399 577 7892 3358 -1196
455 5015 1878 -404 578 7914 3370 -1204
456 5041 1889 -409 579 7936 3383 -1212
457 5066 1901 -414 580 7957 3396 -1220
458 5092 1913 -419 581 7979 3408 -1228
459 5117 1924 -424 582 8001 3421 -1236
460 5142 1936 -430 583 8023 3434 -1244
461 5167 1947 -435 584 8045 3447 -1252
462 5193 1959 -440 585 8067 3459 -1260
463 5218 1971 -445 586 8088 3472 -1268
464 5243 1982 -450 587 8110 3485 -1276
465 5268 1994 -456 588 8132 3498 -1284
466 5293 2006 -461 589 8154 3510 -1292
467 5318 2017 -466 590 8175 3523 -1300
142
468 5343 2029 -472 591 8197 3536 -1308
469 5368 2041 -477 592 8219 3549 -1317
470 5393 2053 -482 593 8240 3562 -1325
471 5418 2064 -488 594 8262 3574 -1333
472 5443 2076 -493 595 8283 3587 -1341
473 5468 2088 -499 596 8305 3600 -1350
474 5493 2100 -504 597 8327 3613 -1358
475 5517 2111 -510 598 8348 3626 -1366
476 5542 2123 -515 599 8370 3639 -1375
477 5567 2135 -521 600 8391 3652 -1383
478 5592 2147 -526 601 8413 3664 -1391
479 5616 2158 -532 602 8434 3677 -1400
480 5641 2170 -537 603 8455 3690 -1408
481 5665 2182 -543 604 8477 3703 -1417
482 5690 2194 -549 605 8498 3716 -1425
483 5715 2206 -554 606 8520 3729 -1434
484 5739 2218 -560 607 8541 3742 -1442
485 5763 2229 -566 608 8562 3755 -1451
486 5788 2241 -572 609 8583 3768 -1459
487 5812 2253 -578 610 8605 3781 -1468
488 5837 2265 -583 611 8626 3794 -1477
489 5861 2277 -589 612 8647 3807 -1485
490 5885 2289 -595 613 8668 3820 -1494
491 5910 2301 -601 614 8690 3833 -1503
492 5934 2313 -607 615 8711 3846 -1511
493 5958 2324 -613 616 8732 3859 -1520
494 5982 2336 -619 617 8753 3872 -1529
495 6006 2348 -625 618 8774 3885 -1538
496 6030 2360 -631 619 8795 3898 -1546
497 6055 2372 -637 620 8816 3911 -1555
498 6079 2384 -643 621 8837 3924 -1564
499 6103 2396 -649 622 8858 3937 -1573
500 6127 2408 -655 623 8879 3950 -1582
501 6151 2420 -661 62315 8883 3952 -1583
143
Appendix I
Table I1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in solid state (29815-35315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 1171 366 -017
299 035 010 000 328 1211 379 -018
300 076 023 000 329 1250 392 -019
301 117 035 000 330 1290 405 -021
302 158 048 000 331 1330 418 -022
303 199 060 000 332 1369 431 -023
304 240 072 -001 333 1409 444 -025
305 281 085 -001 334 1448 458 -026
306 322 097 -001 335 1488 471 -028
307 363 110 -002 336 1527 484 -029
308 404 122 -002 337 1566 497 -031
309 445 135 -002 338 1605 510 -032
310 486 148 -003 339 1644 524 -034
311 526 160 -003 340 1683 537 -036
312 567 173 -004 341 1722 550 -037
313 608 186 -005 342 1761 563 -039
314 648 198 -005 343 1800 577 -041
315 689 211 -006 344 1839 590 -043
316 729 224 -007 345 1877 603 -044
317 770 237 -007 346 1916 617 -046
318 810 250 -008 347 1955 630 -048
319 850 262 -009 348 1993 643 -050
320 891 275 -010 349 2031 657 -052
321 931 288 -011 350 2070 670 -054
322 971 301 -012 351 2108 683 -056
323 1011 314 -013 352 2146 697 -059
324 1051 327 -014 353 2184 710 -061
325 1091 340 -015 35315 2190 712 -061
326 1131 353 -016
144
Table I2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in liquid state (39115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
39115 4413 1056 -191 508 8890 3521 -978
392 4450 1535 -195 509 8924 3538 -986
393 4492 1549 -200 510 8959 3556 -995
394 4535 1566 -204 511 8993 3574 -1004
395 4577 1583 -209 512 9027 3591 -1013
396 4620 1599 -213 513 9062 3609 -1022
397 4662 1616 -218 514 9096 3626 -1031
398 4704 1633 -223 515 9130 3644 -1041
399 4746 1650 -227 516 9164 3661 -1050
400 4789 1666 -232 517 9198 3679 -1059
401 4831 1683 -237 518 9232 3697 -1068
402 4872 1700 -242 519 9266 3714 -1077
403 4914 1717 -247 520 9300 3732 -1087
404 4956 1734 -252 521 9334 3750 -1096
405 4997 1751 -257 522 9368 3767 -1105
406 5039 1767 -262 523 9402 3785 -1115
407 5080 1784 -267 524 9435 3802 -1124
408 5122 1801 -272 525 9469 3820 -1134
409 5163 1818 -277 526 9503 3838 -1143
410 5204 1835 -282 527 9536 3855 -1152
411 5245 1852 -287 528 9570 3873 -1162
412 5286 1869 -293 529 9603 3891 -1172
413 5327 1885 -298 530 9637 3908 -1181
414 5368 1902 -303 531 9670 3926 -1191
415 5409 1919 -309 532 9703 3944 -1201
416 5450 1936 -314 533 9737 3962 -1210
417 5490 1953 -320 534 9770 3979 -1220
418 5531 1970 -325 535 9803 3997 -1230
419 5571 1987 -331 536 9836 4015 -1240
420 5612 2004 -336 537 9869 4032 -1249
421 5652 2021 -342 538 9902 4050 -1259
145
422 5692 2038 -347 539 9935 4068 -1269
423 5732 2055 -353 540 9968 4086 -1279
424 5772 2072 -359 541 10001 4104 -1289
425 5812 2089 -365 542 10034 4121 -1299
426 5852 2106 -371 543 10066 4139 -1309
427 5892 2123 -376 544 10099 4157 -1319
428 5932 2140 -382 545 10132 4175 -1329
429 5971 2157 -388 546 10165 4192 -1340
430 6011 2174 -394 547 10197 4210 -1350
431 6051 2191 -400 548 10230 4228 -1360
432 6090 2208 -406 549 10262 4246 -1370
433 6129 2225 -412 550 10295 4264 -1380
434 6169 2242 -419 551 10327 4282 -1391
435 6208 2259 -425 552 10359 4299 -1401
436 6247 2276 -431 553 10392 4317 -1411
437 6286 2293 -437 554 10424 4335 -1422
438 6325 2310 -444 555 10456 4353 -1432
439 6364 2327 -450 556 10488 4371 -1443
440 6403 2344 -456 557 10520 4389 -1453
441 6442 2361 -463 558 10553 4407 -1464
442 6480 2378 -469 559 10585 4424 -1474
443 6519 2395 -476 560 10617 4442 -1485
444 6557 2412 -482 561 10648 4460 -1496
445 6596 2429 -489 562 10680 4478 -1506
446 6634 2446 -495 563 10712 4496 -1517
447 6673 2464 -502 564 10744 4514 -1528
448 6711 2481 -509 565 10776 4532 -1538
449 6749 2498 -515 566 10808 4550 -1549
450 6787 2515 -522 567 10839 4568 -1560
451 6825 2532 -529 568 10871 4586 -1571
452 6863 2549 -536 569 10902 4604 -1582
453 6901 2566 -543 570 10934 4622 -1593
454 6939 2584 -550 571 10965 4640 -1604
455 6977 2601 -557 572 10997 4658 -1615
456 7015 2618 -564 573 11028 4676 -1626
457 7052 2635 -571 574 11060 4694 -1637
458 7090 2652 -578 575 11091 4712 -1648
459 7128 2670 -585 576 11122 4730 -1659
460 7165 2687 -592 577 11154 4748 -1670
461 7202 2704 -599 578 11185 4766 -1681
146
462 7240 2721 -606 579 11216 4784 -1692
463 7277 2738 -614 580 11247 4802 -1704
464 7314 2756 -621 581 11278 4820 -1715
465 7351 2773 -628 582 11309 4838 -1726
466 7388 2790 -636 583 11340 4856 -1737
467 7425 2807 -643 584 11371 4874 -1749
468 7462 2825 -650 585 11402 4892 -1760
469 7499 2842 -658 586 11433 4910 -1772
470 7536 2859 -665 587 11464 4928 -1783
471 7573 2877 -673 588 11495 4946 -1794
472 7609 2894 -680 589 11525 4964 -1806
473 7646 2911 -688 590 11556 4982 -1817
474 7682 2928 -696 591 11587 5001 -1829
475 7719 2946 -703 592 11617 5019 -1841
476 7755 2963 -711 593 11648 5037 -1852
477 7792 2980 -719 594 11678 5055 -1864
478 7828 2998 -727 595 11709 5073 -1876
479 7864 3015 -735 596 11739 5091 -1887
480 7900 3032 -742 597 11770 5109 -1899
481 7937 3050 -750 598 11800 5128 -1911
482 7973 3067 -758 599 11831 5146 -1923
483 8009 3084 -766 600 11861 5164 -1935
484 8045 3102 -774 601 11891 5182 -1946
485 8080 3119 -782 602 11921 5200 -1958
486 8116 3137 -791 603 11952 5218 -1970
487 8152 3154 -799 604 11982 5237 -1982
488 8188 3171 -807 605 12012 5255 -1994
489 8223 3189 -815 606 12042 5273 -2006
490 8259 3206 -823 607 12072 5291 -2018
491 8294 3224 -832 608 12102 5309 -2030
492 8330 3241 -840 609 12132 5328 -2042
493 8365 3259 -848 610 12162 5346 -2055
494 8401 3276 -857 611 12192 5364 -2067
495 8436 3293 -865 612 12222 5382 -2079
496 8471 3311 -873 613 12252 5401 -2091
497 8506 3328 -882 614 12281 5419 -2103
498 8542 3346 -890 615 12311 5437 -2116
499 8577 3363 -899 616 12341 5456 -2128
500 8612 3381 -908 617 12370 5474 -2140
501 8647 3398 -916 618 12400 5492 -2153
147
502 8681 3416 -925 619 12430 5510 -2165
503 8716 3433 -934 620 12459 5529 -2178
504 8751 3451 -942 621 12489 5547 -2190
505 8786 3468 -951 622 12518 5565 -2203
506 8820 3486 -960 623 12548 5584 -2215
507 8855 3503 -969 62315 12552 5602 -2217
iv
ACKNOWLEDGEMENTS
I am pleased to express my gratitude and appreciation to my advisor Professor Ramana
G Reddy for his patience and guidance during my graduate study and the entire research work I
am greatly benefited from his experience knowledge and enthusiasm for scientific research
I would like to express my sincere thanks to Dr Nitin Chopra and Dr Yang-Ki Hong for
serving on my committee Their valuable suggestions and comments are very insightful for my
research work
I would like to thank all the research colleagues of Dr Reddy‟s research group special
thanks to Dr Divakar Mantha for his valuable suggestions and comments I would like to extend
my gratitude to US Department of Energy for the financial support
Finally I would like to thank my parents and my fianceacutee whose invaluable
understanding and loving support helped me through the difficult times
v
TABLE OF CONTENTS
ABSTRACT ii
DEDICATION iii
ACKNOWLEDGEMENTS iv
LIST OF TABLES viii
LIST OF FIGURES x
CHAPTER 1 INTRODUCTION 1
CHAPTER 2 LITERATURE REVIEW 11
21 Melting point 11
22 Density 15
23 Heat capacity 18
CHAPTER 3 OBJECTIVES 22
CHAPTER 4 THERMODYNAMIC MODELING OF SALT SYSTEMS 24
41 Thermodynamic modeling 24
42 Calculations 27
vi
CHAPTER 5 EXPERIMENTAL PROCEDURE 30
51 Melting point determination of molten salt mixtures 30
511 Materials 30
512 Apparatus and Procedure 30
52 Heat Capacity determination of molten salt mixtures 32
53 Density determination of molten salt mixtures 33
CHAPTER 6 RESULT AND DISCUSSION 34
61 Melting point determination 34
611 DSC equipment calibration 34
612 Results 35
613 Discussion 41
62 Heat capacity determination 51
621 Heat capacity calibration 51
622 Results 52
623 Thermodynamic properties 55
624 Discussion of Gibbs energy change for molten salts 84
63 Density determination 86
vii
631 Density calibration 86
632 Results and discussions 82
64 Thermal energy storage density of molten salts 90
CHAPTER 7 CONCLUSION 94
REFERENCES 96
APPENDIX 104
APPENDIX A 104
APPENDIX B 109
APPENDIX C 114
APPENDIX D 118
APPENDIX E 123
APPENDIX F 128
APPENDIX G 133
APPENDIX H 138
APPENDIX I 143
viii
LIST OF TABLES
21 Melting point of various nitrate salt systems 12
22 Melting point of various carbonate salt systems 13
23 Melting point of various fluoridechloride salt systems 14
24 Melting point of various hydroixde salt systems 15
25 Density coefficients A and B of nitrate salts 16
26 Density coefficients A and B of carbonate salts 17
27 Density coefficients A and B of chloridefluoride salts 17
28 Density coefficients A and B of molten salt mixture with hydroxide salts 18
29 Heat capacity of alkali nitrate salt at 500oC 19
210 Heat capacity of alkali carbonate salt at 500oC 19
211 Heat capacity of fluoridechloride salt at 500oC 20
212 Heat capacity of hydroxide salt at 500oC 21
41 Calculated composition and melting point for multi-component systems 29
61 Calibration data of melting points with different samples 35
62 DSC results of melting point transition point and change of enthalpy 41
ix
63 Fusion and solid phase transition temperature for individual salts 42
64 Melting points of candidate systems as function of temperatures 51
65 Calibration data of heat capacities with different samples 52
66 Heat capacity of selected new TES molten salt mixtures 54
67 Change of Gibbs energy values at 62315K for molten salt systems 85
68 Calibration of density measurements with different pure nitrate salts 86
69 Coefficient of A and B for density determination of salt 1 to salt 9 87
610 Extrapolated value of density and heat capacity at 500oC of salt 1 to salt 9 91
611 Energy density of salt 1 to salt 9 compare to solar salt 92
612 Gravimetric storage densities for solar salt and new molten salts 93
x
LIST OF FIGURES
11 Theoretical and engineering energy conversion efficiency as function of temperature 6
12 Gravimetric storage density for different energy storage systems
as function of temperature 8
51 Photography of set-up for DSC equipment 31
61 Melting point calibration with indium sample 34
62 Melting point calibration with KNO3 sample 35
63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt 36
64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt 37
65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt 37
66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt 38
67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt 38
68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt 39
69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt 39
610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt 40
611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN Salt 40
612 DSC plot of 698wt KNO3 -302wt NaNO2 binary system 43
xi
613 DSC plot of 270wt NaNO3-730wt KNO3 binary system 45
614 DSC plot of 458wtLiNO3-542wtKNO3 binary system 45
615 DSC plot of 460wt NaNO3-540wt KNO3 binary system 46
616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 20oCmin heating rate 47
616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 5oCmin heating rate 48
617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 5oCmin heating rate 49
617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 20oCmin heating rate 49
618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system
as function of temperature 53
619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K 54
620 Change of Gibbs energy as function of temperature for molten salt systems 85
621 The densities of the salt 1 to salt 5 as function of temperature 87
622 The densities of the salt 6 to salt 9 as function of temperature 89
623 Densities of the salt 1 salt 2 as function of temperature compared to
the equimolar NaNO3-KNO3 binary system and pure KNO3 90
624 Gravimetric storage density comparison of different energy storage
xii
systems as function of temperature 93
1
CHAPTER 1
INTRODUCTION
Renewable energy sources such as wind solar water power geothermal and biomass are
playing more and more significant role in our energy supply Because the cheap cost and infinite
amount of energy storage inside the resource solar energy is emphasized since 20th
century and
viewed as promising alternative method to satisfy the large energy consumption every day in the
world reduce the emission of carbon and strengthen the economy
The wind energy was used as a clean energy to generate electricity back to late 19th
century
However this renewable energy source was not emphasized due to the cheap price of fossil fuel
The re-emergence happened in mid 1950s when the amount of traditional energy source was
found apparently decrease The development of wind energy usage continued and in 1990 the
first mega-watt wind turbine was launched which was viewed as a symbol of shift to large scale
wind energy utilization [1-2] The modern application of wind energy mainly relies on wind
turbine On the basis of aerodynamic wind turbine generates certain net positive torque on
rotating shaft and then converts the mechanical power to electrical power As an electrical power
generator wind turbine is connected to some electrical network to transport the electricity to
battery charging utilities residential power systems and large scale energy consuming systems
In general most of wind turbines are small scale and can only generate 10KW electrical power
Only few of the wind turbine systems operate with capacity as large as 5MW Although the
usage of wind energy can reduce the emission of carbon oxide the noise pollution and high cost
2
limit its large scale application Since the wind is not transportable the electrical energy can only
be generated where the wind blows which also decrease the flexibility of wind energy
Water power is another term of alternative power supply and it was used for irrigation
operating machines like watermill even before the development of electrical power The modern
application of water power is to generate electricity by using the gravitational force of falling or
flowing water These days there are various ways for the water power application The most
traditional method is to store the water in dam and generate electricity by converting the
potential energy pump storage is a different way to utilize water power and can change its
output depending on the energy demand by moving water between reservoirs at different
elevations In the low energy demand period excess energy is used to lift water to the higher
level while in the peak period of energy demand the water is released back to the lower
elevation through water turbine Water power can also be converted by taking advantage of
naturally raise and fall of tide to satisfy the demand of electrical energy consumption [3]
Although the usage of water power can reduce the emission of carbon dioxide and cost it will
destroy the ecosystem because of the large land required for construction There will be methane
emission from the reservoir the potential failure hazard of dam is also a fatal issue and flow
shortage caused by drought may also create serious problem As result of that water power
technique is not a long-term alternative choice
Geothermal energy is the energy form generated inside the earth At the very beginning of
the planet formation a large amount of thermal energy was stored from the radioactive decay of
minerals volcanic activity and solar energy absorption Because of the temperature difference
3
between the core and the surface of planet the thermal energy stored inside the earth is driven to
the outer surface in the form of heat This form of renewable energy source can be applied to
generate electrical power and heat for industrial space and agricultural applications
Theoretically the deposited amount of geothermal energy is adequate to supply the energy
consumption in the world However most of the geothermal energy is stored deeply near the
core of the earth the deep drilling and exploration of geothermal energy is very expensive and
limits the large-scale use of this renewable energy source [4]
Biomass is a renewable energy source used to generate heat or electricity with living or
recently living organism such as wood waste (hydrogen) gas and alcohol fuels The biomass
energy can be converted to electrical energy by thermal method such as combustion pyrolysis
and gasification Several specific chemical processes may also be able to convert the biomass
energy to other forms The main problem arise from application of biomass is air pollution which
contains carbon monoxide NOx (nitrogen oxides) VOCs (volatile organic compounds)
particulates and other pollutants And the level of air pollution to some extent is even above that
of traditional fuel resource Some other possible issue like transportation and sink of carbon also
limit the wide usage of this type of alternative energy [5]
Among all the renewable energy sources solar energy is the most suitable alternative
energy for our future life It is clean cheap abundant without any noise air pollution no
transportation issue and easy to be obtained anywhere in the earth Inside the core of the Sun
hydrogen fuses into helium with a rate of 7times1011
kgs and generates very powerful nucleation
power This type of nucleation explosion creates ultra high temperature in the core of the Sun
4
which reaches approximately 16 million K degrees Although the Sun is not perfectly black body
it still radiates abundant power with the energy density as 16times107 wattsm
2 [6-7] Because of the
enough amount of hydrogen underneath the surface of the Sun the radiation given arise of from
the nucleation explosion can continue at least 5 million years with the same rate and strength
The energy reaching the earth is vastly reduced mainly caused by the absorption and spreading
of the radiation It is easily to understand that there are numerous amorphous objects all around
the entire universe which can absorb certain portion of the radiation for the Sun Moreover the
light generated from the spherical object such as the Sun fills all the available space between the
origin to the destination Even though the energy will not be lost in the travelling process due to
the long distance between the Sun to the earth the surface area of the sphere which is formed
with the Sun as center and the distance as radius is much larger than that of the earth As the
result of that only 1340Wm2 finally reaches the upmost surface of the earth Even though the
final amount of the received solar energy is very small compared to that is initially radiated from
the Sun the average daily solar radiation falling on one area in the continental United States is
equivalent in total energy content to 11 barrels of oil In summary the solar energy itself is
relatively unlimited useful clean and almost unexploited energy and definitely can behave as
the promising mean for the future energy supply [8]
There are several different methods to take advantage of the solar energy and all the
methods can be distinguished into three group solar parabolic trough solar tower and solar dish
Parabolic trough is constructed by silver coated parabolic mirror and there is a Dewar tube going
through the length of the mirror and set on the focal point all the radiation is concentrated on the
tube and transfer by heat transfer fluid to the thermal energy storage unit Solar tower are used to
5
capture solar energy with thousands of mirrors and focus the concentrated sunlight to the top of
the tower which is located in the middle of the heliostats The thermal energy storage medium
within the tower was heated to high temperature and transferred to thermal energy storage tank
and eventually sent to steam pump The solar dish is built with a large reflective parabolic dish
which concentrates all the received sunlight to one spot There is normally a receiver located on
the focal point and transform the solar energy to other forms of useful energy The working
upper limit temperature of solar parabolic trough system is the lowest among these three systems
normally its maximum working temperature is within the range from 400-500oC the solar tower
has higher maximum working temperature which ranges from 500-1000oC the solar dish has the
highest working upper limit temperature which reaches 700-1200oC [9]
The energy conversion efficiency is the most concerned parameter in the solar energy
storage application and the theoretical and real engineering efficiency are given in fig 11 as
function of temperature The theoretical conversion efficiency can be up to 80 while in real
application the value is always less than 70 regardless of collectors The actual efficiency
increases with temperature in the whole working temperature As a result of that the thermal
energy storage materials in solar parabolic trough for instance should be able to work stably at
the upper limit temperature of this type of collection system which is 500oC to ensure the highest
efficiency [9 10]
6
Fig 11 Theoretical and engineering energy conversion efficiency as function of
temperature
Solar energy can be stored in three major forms sensible heat latent heat and
thermochemical heat Sensible heat storage was utilized based on the heat capacity and the
change as function of temperature of storage materials in the charging and discharging process
which correspond to the absorbing and withdrawing energy processes respectively The sensible
heat stored from the melting point to the maximum working temperature can be expressed by
equation 1 [9]
[1]
Where m is the mass of storage material Tmp and TH are melting point temperature and high
temperature in the same phase respectively Cp(T) is the heat capacity at different temperature
Because the sensible heat storage materials remain in a single phase in the working temperature
range the charging and discharging processes are completely reversible for unlimited cycles
7
Latent heat storage is operated by absorbing and withdrawing energy in the charging and
discharging processes accompanied with fusion of materials [9] The latent heat collected
throughout the working temperature range can be expressed by equation 2 as following
[2]
Where T is temperature in solid state Tmp is melting point temperature of storage material TH is
the high temperature in liquid state and is enthalpy of fusion
Thermochemical heat storage is based on the heat capacity and its change as function of
temperature accompanied with chemical reaction The thermochemical heat collected throughout
the working temperature range can be expressed by equation 3
[3]
Where TL is the low temperature before the reaction TR is the reaction temperature and
is the enthalpy of chemical reaction Because of the destruction of the chemical bonds
in the reaction process the charging and discharging process cannot be completely reversible
which reduces the stability and recyclability of storage operation [10]
Sensible energy storage method is chosen to ensure the efficient usage of solar energy for
parabolic trough system of which the maximum working temperature ranges from 400-500oC
Different from thermochemical heat storage the sensible heat storage can achieve completely
reversible working condition under unlimited cycles Also fig 12 illustrates that the sensible
heat storage materials mainly work in the working temperature range for parabolic trough system
8
and the gravimetric energy storage densities of sensible heat is higher than that of latent heat
materials [9 -11]
Fig 12 Gravimetric storage density for different energy storage systems as function of
temperature
Various materials are chosen to serve as thermal energy storage fluid for sensible heat
such as water thermal oil ionic liquid and molten salt [12] The properties of different heat
transfer fluid determine the performance of solar energy heating system In these days the
efficiency and cost of output of electrical power mainly relies on the parabolic trough solar
power plant and the thermal storage fluid [12] A large investment cost is needed to dispatch
100MW to 200MW energy by consuming the energy transfer fluids Given by this situation the
development of new thermal storage fluid with higher thermal energy storage density is
paramount to lower the expense for generating energy and a lot of effect has been put on design
of new systems [13-16]
9
Water is commonly used as heat transfer and thermal energy storage fluid in industry
because of its low cost high heat capacity and high thermal conductivity However the
limitation for using this medium is also obvious that the temperature range within which the
liquid state can be assured is too small It is well know that water can only serve as thermal
energy storage liquid above the freezing point 0oC and below the boiling temperature 100
oC In
practical experiment the actual temperature range is even less than 100oC because of the large
amount of weight loss near the boiling temperature due to the high vapor pressure Water is
possible to work above 100oC only if high pressure is also applied to avoid the phase
transformation but the cost will be highly increased Accordingly water is only suitable to work
in low temperature below 100oC
Thermal oils are also being used in the parabolic trough solar power plant and have very
low melting point as low as 12oC [17 18] However the application of the oil for the thermal
energy storage liquid is limited by some disadvantages from the physic-chemical properties The
upper limit for this oil is only 300oC and above that the liquid state cannot be maintained
Moreover the low thermal decomposition temperature low density and low heat capacity result
in limited thermal energy storage capacity Since the working temperature range is so narrow the
rankie cycle efficiency is reduced when using the synthetic oil and the cost for generating power
is considered to be very expensive [19 20]
Ionic liquid is another medium served as thermal energy storage fluid The liquid
temperature range of ionic liquid is large which is one of the main advantages of this type of
material The high heat capacity and density ensure the efficiency of thermal energy storage of
10
ionic liquid What‟s more the excellent chemical stability and little vapor pressure increase the
lifetime [21-24] However as a result of the very serve corrosion problem to the liquid container
and the high cost the usage of ionic liquid is still limited
Considering various relative physic-chemical properties of thermal energy storage system
molten salts have been proposed as a suitable group for a wide temperature range application
They are being emphasized in the solar energy applications because of their low melting point
and high upper limit which can increase the stable working range The high heat capacity
increases the thermal energy storage density of the heat storage system excellent thermal
stability and negligible vapor pressure ensure the steadiness of cyclic repeating in the lifetime
[25] low viscosity strengths the mobility and efficiency of the thermal storage liquid low
utilization cost reduce the investment and protect the economy The liquidus temperature range
of the molten salt varies from 150-600oC combination of various salts can bring the melting
down and further increase the working temperature range Due to these properties molten salts
can be excellent thermal energy storage fluid in the solar power generation system
11
CHAPTER 2
LITERATURE REVIEW
Several physical and thermodynamic properties of thermal energy storage fluid play
significant role in determining the efficiency and performance of solar energy storage systems In
order to evaluate the feasibility of systems the physic-chemical properties of several molten salts
should be reviewed The three determining parameter which directly affect the thermal energy
storage capacity in systems are melting point heat capacity and density
There are large amount of melting point data available in the literature for various molten
salt system in previous literatures while those with melting point less than 120oC is very limited
All the previous study on molten salt system revealed that five group of molten salts are
emphasized and commonly used alkai or alkaline nitrates carbonates sulphates chloride and
hydroxides Although most of the systems have the same group of cation the melting point
varies a lot from one to anther due to the different effect of anions
21 Melting point
The melting points of individual and multi-component nitratenitrite systems are listed in
Table 21[26-31] Among those systems solar salt (NaNO3KNO3 6040) is the thermal energy
storage medium which is currently being used with the freezing point of 221oC [27] Although
the melting point for this system is highest in all the candidate mixtures in this group the lowest
12
combined compound cost makes it widely used in solar energy storage field Another ternary
system HITEC which contains NaNO3 KNO3 and NaNO2 has freezing point of 141 oC [28]
This combination brings the melting point down but the lack of combination of optimum features
limits its further application [29] Some mixtures such as LiNO3-Ca(NO3)2-KNO3 are not often
utilized because they increase the compound cost at the same time of lowering the melting point
to around 120oC [30] moreover the decreased melting point is still high compared to the
organic oil There are also several systems have the melting points less than 100oC or even 60
oC
they are not used in the parabolic trough solar power plant due to the decomposition of some
components during high temperature [31]
Table 21 Melting point of various nitrate salt systems
Compound Melting Point (ordmC)
LiNO3 253
NaNO3 307
KNO3 334
Ca(NO3)2 561
Sr(NO3)2 570
Ba(NO3)2 590
NaNO3-NaNO2 221
NaNO3-NaNO2-KNO3 141
NaNO3-KNO3-CaNO3 133
LiNO3-KNO3-NaNO3 120
KNO3-CaNO3-LiNO3 117
LiNO3-KNO3-NHNO3 92
KNO3-NHNO3-AgNO3 52
The melting points of individual and multi-component carbonate systems are listed in
Table 22 [26 32 33] Different from the nitrate salts the melting points for both the individual
13
and multi-component carbonate systems are on the higher side The lowest melting point is
achieved with lithium sodium and potassium carbonate ternary system whose melting point is
still 277oC higher than that of the nitrate ternary system with the same cations [32] Besides
because of the thermal decomposition issue the choice of component involved in the multi-
component carbonate systems is limited Some salt like CaCO3 doesn‟t have stable form at high
temperature and the lack of multi-component system reduces the chance of the synthesis of low
melting point salt mixtures Even though this group of salt is not thermally stable and the
working temperature range is relatively small it is still viewed as possible candidate working at
high temperature due to its low price
Table 22 Melting point of various carbonate salt systems
Compound Melting Point (ordmC)
Li2CO3 732
Na2CO3 858
K2CO3 900
MgCO3 990
Na2CO3-K2CO3 710
Li2CO3-Na2CO3 496
Li2CO3-K2CO3 488
Li2CO3-K2CO3-Na2CO3 397
Alkali and Alkaline fluoridechloride salts are also selected as one possible choice as the
thermal energy storage fluid and the melting point examined from previous literatures are given
in table 23 [34-38] A lot of study has been done for this group of salt and the melting points
were found in the same range as the carbonate group And for the pure salt metal chloride salts
have lower melting point than metal fluoride ones
14
Table 23 Melting point of various fluoridechloride salt systems
Compound Melting Point (ordmC)
LiF 849
NaF 996
KF 858
LiCl 610
NaCl 801
KCl 771
LiF-KF 493
LiF-NaF 652
LiCl-KF 487
LiF-NaF-KF 454
LiF-NaF-KF-MgF2 449
LiF-KF-BaF2 320
LiF-KF-CsF-RbF 256
Several studies were also conducted to determine the melting point of molten hydroxide
salts and the results are shown in Table24 The data of pure salts and multi-component mixtures
merely in this group were not much determined in the literatures Generally they are mixed with
other groups of anion and form some low melting point salt mixtures [39-42] On the basis of the
previous literature data alkali hydroxide salts and their mixture with salts in other groups have
relatively lower melting point compared with pure carbonate and fluoride chloride group salt
mixtures Most of the melting points given in Table 4 are lower than 300oC sodium potassium
hydroxide binary mixture even reaches the melting point below 200oC Accordingly relatively
large temperature range can be obtained by using hydroxide salt mixtures or adding them as
additive
15
Table 24 Melting point of various hydroixde salt systems
Compound Melting Point (ordmC)
LiOH-LiF 427
NaOH-KOH 170
LiOH-NaOH 213
NaOH-NaNO2 232
NaOH-NaNO3 237
NaOH-NaCl-NaNO3 242
NaOH-NaCl-Na2CO3 282
22 Density
For the solar energy storage system density for the thermal energy storage fluid is also
essential parameter The density is needed for the size calculation as function of temperature and
assessing for the thermal stability of thermoclines Besides density as function of temperature is
used to evaluate the volume change in the process of freezing which contributes to potential
stress
Alkalialkaline nitrate salts were studied very much about their density as function of
temperature All the results indicate that the density was decreased linearly as temperature
increases and any specific density value in the molten state can be expressed by equation as
equation 4
= A-BT [4]
Where (gcm3) is the density of salt A (gcm
3) is the initial density value at 0
oC and B
(mgcm3degC) is the density change slope as function of temperature The coefficients are shown in
16
Table 25 for the nitrate group molten salts Among these systems pure sodium nitrate has the
largest value which reveals the high initial density value at low temperature [43] Conversely
lithium nitrate has the lowest value while it presents the smallest decrease trend as temperature
increases [44] The densities and A B values of multi-component nitrate salts were included in
the range of those two salts discussed above
Table 25 Density coefficients A and B of nitrate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiNO3 1922 0556
NaNO3 2334 0767
KNO3 2127 0760
NaNO3-KNO3 2134 0773
KNO3-CaNO3-LiNO3 2172 0735
LiNO3-KNO3-NaNO3 2083 0715
Several experiments were also conducted to measure the density as function of temperature
for the individual and multi-component carbonate salt systems The density of the carbonate salt
also follow the same trend as that of nitrate salt and the temperature dependence of density
followed the linear equation as discussed above It is observed that all the carbonate salts have
higher initial density coefficient A than the nitrate salt The largest value is reached to 2511 and
even the lowest value in this group is greater than the maximum A of nitrate group [45-49]
What‟s more the regression slope coefficient B of carbonate salt is lower compared to that of the
nitrate salt group Accordingly the salts in this group present larger density in the molten state
and the density coefficient A and B are given in Table 26
17
Table 26 Density coefficients A and B of carbonate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
Li2CO3 2303 0532
Na2CO3 2350 0448
Na2CO3-K2CO3 2473 0483
Li2CO3-K2CO3 2511 0599
Li2CO3-Na2CO3 2456 0519
Li2CO3-Na2CO3-K2CO3 2364 0544
Density of metal fluoride and chloride molten salt were also examined and present similar
regression trend as temperature increases The linear temperature dependence is also expressed
by the same equation On the basis of previous literature data the pure chloride salt shows lower
density than the fluoride salt with the same cation in the molten state [49] What‟s more the
sodium halide salt has the largest density value while the lithium halide salt has the lowest value
which is very similar to the nitrate group salt The density determination coefficient A and B are
given in Table27
Table 27 Density coefficients A and B of chloridefluoride salts
Compound A(gcm3) Btimes103(gcm
3degC)
LiCl 1766 0432
NaCl 1991 0543
KCl 1976 0583
LiF 2226 0490
NaF 2581 0636
KF 2469 0651
LiF-NaF 2520 0818
LiCl-NaF-KCl 2436 0742
LiF-NaF-MgF 2240 0701
18
The density measurement of hydroxide was not conducted as much as those three anion
groups discussed above Only few data of density is available for the alkali hydroxide salt when
added into other salt systems and temperature dependence also follows the linear regression
trend [32 41] The density determination coefficient A and B are given in Table 28
Table 28 Density coefficients A and B of molten salt mixture with hydroxide salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiCl-LiOH 16 0443
LiF-LiOH 165 0471
23 Heat capacity
In the heating process the temperature of solar energy storage molten salt is increase by
absorbing energy from the solar radiation Conversely the same amount of heat is released and
applied to heating system in the process of cooling Heat capacity is the amount of heat required
to increase the temperature of certain material by 1 oC and can be viewed as the directly relevant
parameter to the energy storage ability To some extent the large heat capacity assures the
efficiency of the application of solar energy storage materials
The heat capacity of alkalialkaline nitrate salt was investigated for both individual and
multi-component system in the previous literature To simplify the comparison only the heat
capacity value at 500oC is shown in all the following tables In the liquid state the heat capacity
increases with temperature following linear equation and the increasing slope is as small as 10-5
to 10-4
[50 51] Among those alkali nitrate salt systems lithium nitrate has the largest heat
19
capacity at 500oC while potassium nitrate presents the lowest value at that temperature In table
29 the heat capacity results at the selected temperature in literature are given
Table 29 Heat capacity of alkali nitrate salt at 500oC
Compound Heat capacity(JgK)
LiNO3 2175
NaNO3 1686
KNO3 1400
NaNO3-KNO3 1533
LiNO3-KNO3 1642
LiNO3-KNO3-NaNO3 1681
For the carbonate salt systems in the molten state the heat capacity is almost constant and
almost independent with temperature [32 33] Same as the nitrate group salts the heat capacity
for pure carbonate salt decreases as the atomic number of the alkali element increases which
means the value for lithium carbonate is the largest and that of potassium carbonate is the
smallest Generally the heat capacity value for carbonate in molten state is larger than that in
solid state However the sodium-potassium carbonate binary system is an exception for which
the heat capacity in solid state is larger than liquid state In table 210 the heat capacity results of
carbonate salts at the selected temperature in literature are given
Table 210 Heat capacity of alkali carbonate salt at 500oC
Compound Heat Capacity(JgK)
Li2CO3 250
Na2CO3 178
K2CO3 151
Na2CO3-K2CO3 157
20
Li2CO3-K2CO3 160
Li2CO3-Na2CO3 209
Li2CO3-K2CO3-Na2CO3 163
The heat capacity of fluoridechloride salt was measured in several literature and found
that for the pure salt the lithium halide has the biggest heat capacity data in the molten state
while the potassium halides shows the lowest heat capacity value Similar to the carbonate group
the heat capacity value of fluoridechloride salt varies little with temperature in the liquid state
[32 33] The values at 500oC for the alkalialkaline halides are shown in Table 211
Table 211 Heat capacity of fluoridechloride salt at 500oC
Compound Heat Capacity (JgK)
LiCl 148
NaCl 115
KCl 090
LiF-KF 163
NaCl-MgCl2 100
LiF-NaF-KF 155
KCl-MgCl2-CaCl2 092
The heat capacity of pure and multi-component hydroxide salt systems is limited in the
previous literature and the values in the liquid state follow linear equation which is observed for
all the molten salt discussed above [52] The values at 500oC for the alkalialkaline halides are
shown in Table 212
21
Table 212 Heat capacity of hydroxide salt at 500oC
Compound Heat Capacity(JgK)
NaOH 188
LiOH-NaOH 221
NaOH-KOH 182
In summary on the basis of comparison of various physic-chemical properties molten
nitrate slats have relatively low melting point excellent working temperature range reasonable
density and high heat capacity As the result of that molten nitrate salt is suitable to be applied as
the thermal energy storage fluid in the solar energy storage system
22
CHAPTER 3
OBJECTIVES
Based on review of previous literature data it is found that there are several disadvantages
such as the high melting point relatively low density value or poor heat capacity in liquid state
which limit the application of molten salt in certain groups in solar thermal energy storage
system Conversely alkalialkaline nitrate salt is considered as the suitable choice and proposed
as the thermal energy storage liquid for high temperature
Currently the used thermal energy storage liquid is NaNO3 (60mol)-KNO3 (40mol)
binary system (solar salt) which has the melting point at 221oC [30] Although the melting point
for this salt mixture is not the lowest it is still emphasized because of its low investment cost
However there are some drawbacks for this binary nitrate mixture The main disadvantage is
the high melting point In evenings or in winter the molten salt can easily freeze and block the
pipeline As a result of that some auxiliary cost should be added to overcome this problem and
the total investment will be increased
Development and synthesis of newer molten salt mixtures with freezing point lower than
those currently used for thermal energy storage applications is necessary for higher efficiency of
utilization of solar energy and getting rid of any unnecessary cost The approach to develop
lower freezing point molten salt mixtures is by the prediction of new eutectic mixtures and also
23
by the development of new nitrate compounds Besides these two most well known systems
several other mixtures were also studied Preliminary evaluation of several new molten salt flux
systems based on requirements for thermal energy storage systems mainly including freezing
point density heat capacity viscosity and thermal energy storage density The promising
candidate low melting point molten salt system should satisfy the requirements that eutectic
melting temperatures are lower than 220oC and the thermal energy storage densities are higher
than binary solar salt It is known that the melting point can be lowered by the addition of one or
more ABNO3 nitrate compounds where A and B are cations Consequently several multi-
component systems which have more constituent salts than solar salt were came up with and
studied with little fundamental data on the physic-chemical properties at the required operating
conditions available at present
In this thesis the new systems with simulated eutectic compositions were tested for their
experimental melting points heat capacities using the Differential Scanning Calorimetry (DSC)
technique which is considered to be the accurate instrument for thermodynamic data analysis
[53-59] Some significant thermodynamic properties such as heat capacity enthalpy and entropy
and Gibbs energy were calculated in the thesis to evaluate the energy change of the system in the
phase change process and the potential of being applied in the parabolic trough solar power plant
The energy density was obtained by using the experimental measured density and heat capacity
of the mixtures in molten state Finally 9 down-selected systems were present and discussed
24
CHAPTER 4
THERMODYNAMIC MODELING OF SALT SYSTEMS
41 Thermodynamic modeling
To lower the melting point of solar energy storage system multi-component system is
applicable Thermodynamic model was introduced to predict the eutectic temperature of salt
systems based on the Gibbs energies of fusion of individual salt and that of mixing of constituent
binary systems At the eutectic temperature the Gibbs energies in the liquid state and solid state
of salt are equal In thermodynamics Gibbs energy of fusion can be expressed by the equation
given as follows
G = H-TS [5]
Where H is the change of enthalpy of fusion and S is the change of entropy of fusion Equally
the entropy change of fusion can be expressed by differentiating G and the equation is given
[6]
It is known that the change in entropy can be expressed in terms of change in heat capacity in the
melting process as
[7]
25
If the change of heat capacity is assume to be independent of temperature the integral of
from Tm to T can be shown as
[8]
where Sm is the entropy of fusion at the melting point which is equal to Accordingly
Eq8 can be rewritten as
[9]
Substituting Eq 9 in Eq 6 and integrating the equation from Tm to T we get
[10]
Eq 10 illustrates that by using the change of heat capacity melting point and enthalpy of fusion
the Gibbs energy change at any temperature can be obtained
The standard Gibbs energy of fusion of a salt bdquo1‟ can be expressed in terms of the activity
of the salt as
[11]
where is the molar excess Gibbs energy and X1 is the molefraction of the salt bdquo1‟ Gibbs
energy of fusion at any give temperature T is expressed by Eq 7 in terms of its molefraction and
partial molar excess Gibbs energy
26
Take LiNO3-NaNO3-KNO3 as an example in which the integral molar excess Gibbs energy is
composed of the summation of the Gibbs energies of three constituent binary system and one
ternary The expression of the integral excess Gibbs energy is given by Eq12
[12]
Gibbs energies of the three constituent binary systems LiNO3-NaNO3 LiNO3-KNO3 and
NaNO3-KNO3 of the LiNO3-NaNO3-KNO3 ternary system are taken from the literature [48 49]
The Gibbs energies of mixing or the integral excess Gibbs energies of the three constituent
binary systems of the LiNO3-NaNO3-KNO3 ternary system are given below
LiNO3-NaNO3 Binary System
Jmol [13]
LiNO3-KNO3 Binary System
Jmol [14]
NaNO3-KNO3 Binary System
Jmol [15]
When assume the intergral excess Gibbs energy of to be zero the excess Gibbs energy in
the ternary system can be expressed by the summation of three constituent binary systems
[16]
27
Generally the partial molar excess Gibbs energies are reduced from the integral molar
excess Gibbs energy and can be expressed by the generalized equation for certain ldquomrdquo
component salt as
[17]
In the ternary system the i value equals to 12 and 3 and the partial molar excess Gibbs energy
of mixing for each component can be expressed as follows
[18]
[19]
[20]
Based on Eq 7 and the partial molar excess Gibbs energy of individual component the
Gibbs energy in the fusion can be expressed as Eq21- 23
[21]
[22]
[23]
42 Calculations
The fusion of the ternary salt system is defined by solutions of Eq 21-Eq 23 Newton-
Raphson method can be used to solve these three non-linear equations by linearizing the non-
linear equations using the Taylor series and truncating the series to first order derivatives
28
Consider the three non-linear functions F G and H in three variables x y and z The three
equations that are solved for the three variables are written as
F(x y z) = 0
G(x y z) = 0
H(x y z) = 0 [24]
The partial derivatives of the function F with respect to x y and z are given as
[25]
Similarly the partials derivatives can be expressed for the other two functions G and H
Newton-Raphson iterative method of solving the three equations in three variables
essentially deals with the solution of the incremental vector in the matrix equation given below
[26]
For the initial values of x y and z (say xi yi and zi) the right hand side vector contains the
values of the functions at the initial values (xi yi and zi) The 3times3 matrix on the left hand side
contains the partial derivatives of the functions with respect to the three variables at the initial
values Solutions of the matrix equation (Eq 26) result in the increments of the variables x y
and z The variables for the next iteration will then be xi + x yi + y and zi + z The
process of solving the matrix equation (Eq 26) is continued until the increments in the variables
x y and z is less than a very small quantity The iteration process is then said to be
29
converged and the values of the variables at convergence of the solution are the roots of the
system of the three fusion equations
The composition of LiNO3 NaNO3 and KNO3 and the eutectic temperature is solved by
using the Newton-Raphson iterative method Different from the data in previous literature the
eutectic temperature for the ternary is 116oC Besides the composition for each component is
also different from those published in literatures The new molten ternary system is composed of
2592 wt LiNO3 2001 wt NaNO3 and 5407 wt KNO3 The similar method is also applied
to other multi-component systems to determine the composition and eutectic temperature The
predicted melting points for new solar energy storage system are given Table41
Table 41 Calculated composition and melting point of multi-component molten salts systems
System Composition (wt) Calc Tmp
LiNO3 NaNO3 KNO3 NaNO2 KNO2 Mg(NO3)2 MgKN (degC)
Salt 1 259 20 541 - - - - 116
Salt 2 - 161 547 292 - - - 1238
Salt 3 175 142 505 178 - - - 986
Salt 4 115 104 274 - - - 507 986
Salt 5 172 139 476 172 41 - - 957
Salt 6 9 423 336 - 151 - - 1000
Salt 7 193 - 546 237 24 - - 1081
Salt 8 193 - 559 239 - 09 - 1008
Salt 9 154 172 324 - - 83 267 1036
30
CHAPTER 5
EXPERIMENTAL PROCEDURE
51 Melting point determination of molten salt mixtures
511 Materials
Ternary quaternary and quinary nirate and nitrite mixtures were tested in the thesis Most
components in the mixtures don‟t require any pre-preparation and can be used as received The
only exception is new developed MgKN which was composed of 6667 mol KNO3 and 3333
mol Mg(NO3)2 This unique compound is synthesized from magnesium nitrate hexahydrate
(98 Alfa Aesar) and potassium nitrate (ACS 990 min Alfa Aesar) and added into the
mixture as one single component As received magnesium nitrate hexahydrate is dehydrated
before synthesizing MgKN compound Weighted amount of magnesium nitrate taken in a
stainless steel crucible and placed on a hot plate in an argon atmosphere Temperature of the salt
is measured with a thermocouple immersed in the salt The temperature was held at 52315 K for
2 hours The salt solidifies to a white mass The temperature of the salt is then raised to 57315 K
slowly to remove any traces of moisture and to ensure complete dehydration The complete
removal of water is ascertained by weight loss
512 Apparatus and Procedure
31
Differential scanning calorimetry (DSC) analysis was performed using Perkin Elmer
Diamond DSC instrument and the setup is shown in fig 51 Heat flow and temperature can be
recorded in the instrument with an accuracy of 00001 mW and 001 K respectively The
measurements were made under purified nitrogen atmosphere with a flow rate of 20ccmin and at
a heating rate of 5 Kmin
Fig 51 Photography of set-up for DSC equipment
After dehydration if necessary each component was weighed to an accuracy of 01mg with
the electrical balance and mixed thoroughly in a stainless steel crucible Later the mixture is
heated up to certain temperature at which the entire salt melts At this temperature the salt
mixture was held for about 30 minutes The salt mixture is allowed to air cool to ambient
temperature This procedure is repeated 3 to 4 times to get the well-mixed compound Standard
aluminum pan with lid used for DSC measurements are weighed before the experiment Small
amount of the synthesized compound is placed carefully in the aluminum pan and closed with
the lid The lid is crimped by a sample press and the pan is weighed The weight of the sample is
32
determined by removing the weight of the pan and lid For the determination of melting point
and heat capacity (20-25) mg of the sample was used
Perkin-Elmer Diamond Differential Scanning Calorimeter (DSC) is used to measure the
melting point and heat capacity of compound The crimped ample pan was immediately put
inside the sample chamber of DSC after preparation and held at 52315 K for 10 hours to remove
the trace amount of moisture possibly caught in the process of loading sample and also to ensure
a homogeneous mixture In the experimental procedure a temperature range from 29815 K to
52315 K was set with a heating rate of 5 K min
1 followed by a cooling cycle at the same rate
This cycle is repeated for at least 6 times to ensure good mixture of the sample and
reproducibility of the results
52 Heat Capacity determination of molten salt mixtures
To start Cp measurement the same procedure as that of melting point determination is
followed with an addition of bdquoiso-scan-iso‟ steps to the program after 5-cycle temperature scan
Starting from 29815 K the temperature was held for 5 minutes before and after each scan step
Small temperature scan range is chosen to avoid thermal resistance between device and testing
sample except when the temperature is approaching the melting temperature The upper limit for
the Cp measurement was set to 62315 K in our experiments Since the change in the molar heat
capacity of the salt in the liquid state is very small the Cp data in the liquid state can be easily fit
to an equation and extrapolated to higher temperatures To get the value of molar heat capacity
of the sample heat flow curve for the baseline of the empty sample pan also needs to be obtained
immediately following the identical ldquoiso-scan-isordquo steps which were used for the actual sample
33
run The difference of heat flow between the actual crimpled sample and the empty sample pan is
the absolute heat absorbed by the test sample
53 Density determination of molten salt mixtures
Density measurement was carried out with standard densitometer which has fixed volume
Initial weight of the densitometer is measured and noted Salt composition of which the density
is measured is placed in a beaker on a hot place The densitometer is also placed on the same hot
plate The temperature is set to a fixed value above the melting point of the salt and is measured
by a thermocouple After the salt is melted and when the temperature shows stable reading the
molten salt is poured in to the densitometer up to the set mark on the sensitometer bottle The
weight of the densitometer with the molten salt is measured The weight difference between this
weight and the weight of empty densitometer gives the weight of the molten salt at the fixed set
temperature By knowing the fixed volume in the densitometer the density of the salt at that
temperature can be calculated This procedure is repeated at least three times to accurately
determine the density of the salt
34
CHAPTER 6
RESULT AND DISCUSSION
61 Melting point determination
611 DSC equipment calibration
Before the actual melting point measurement pure indium zinc metal and several
individual salts were used to calibrate the DSC equipment For metals only one sharp peak was
observed for each and the heat flow curve for indium metal is shown in fig 61 However larger
and boarder peaks are found for salts just like the condition illustrated in fig 62 for pure
potassium nitrate Based on the results shown in Table 61 the experimental data for melting
points and enthalpies of fusion have excellent agreement with the literature values [60-63] The
variation of point is within 07 and the variation of change of enthalpy is less than 3
Figure 61 Melting point calibration with indium sample
35
Figure 62 Melting point calibration with KNO3 sample
Table 61 Calibration data of melting points with different samples
Sample
Lit
Tmp
Expt
Tmp
Lit
Ttrans
Expt
Ttrans
Lit
ΔHfusion
Expt
ΔHfusion
Lit
ΔHtrans
Expt
ΔHtrans
degC degC degC degC Jg Jg Jg Jg
Indium 1566 1563 - - 286 278 - -
Zinc 4195 4188 - - 1086 1068 - -
LiNO3 2567 2550 - - 3617 3633 - -
NaNO3 3100 3081 2770 2753 1777 1756 147 152
KNO3 3370 3372 1330 1332 993 1005 538 529
612 Results
Differential scanning calorimetry (DSC) was used to determine the melting point and any
solid state phase transitions of the salt mixture A low scanning rate was chosen to record the
heat flow curve as function of temperature in order to improve the sensitivity of detection [64] It
helps to pick up any small endothermic peaks and also avoids the thermal resistance between the
36
internal furnace and sample Nine systems were chosen to test and the eutectic composition is
already listed in Table 41
All the selected systems are composed of alkaline nitrate and nitrite and most of them have
three basic components which are lithium sodium potassium nitrate or nitrite All the quaternary
and quinary systems were developed on the basis of the LiNO3-NaNO3-KNO3 baseline ternary
Figure 63-611 shows the DSC plot of all the salt systems DSC plots for each system were
collected for at least five runs (each run with fresh salt preparation) to ensure the reproducibility
All the onset temperatures peak temperatures predicted temperatures enthalpy of fusion for
melting peaks and the solid phase transformation temperatures are given in Table62
Figure 63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt
37
Figure 64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt
Figure 65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt
38
Figure 66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt
Figure 67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt
39
Figure 68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
Figure 69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
40
Figure 610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt
Figure 611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN salt
Table 62 illustrates that the predicted melting point is close to the experimental
determined value and most deviation is within 10 except for system 9 The great agreement
41
between experimental and calculated data verifies the accuracy and feasibility of the
thermodynamic modeling
Table 62 DSC results of melting point transition point and predicted melting point
System Tmp Ttrans ΔHfusion
Calculated degC Onset degC Peak degC Peak degC Jg
Salt 1 1160 994 1191 1043 600
Salt 2 1238 1150 1240 NA 97
Salt 3 986 940 999 NA 244
Salt 4 986 940 1010 NA 60
Salt 5 957 910 950 NA 62
Salt 6 1000 930 960 NA 86
Salt 7 1081 992 1003 793 60
Salt 8 1008 1010 1019 853 59
Salt 9 1036 834 892 NA 93
613 Discussion
It is observed that the first curve is different from last ones shown in the DSC plots and
this phenomenon is common for all the melting point measurement with DSC technique This
happened because in the first cycle the moisture caught by salt mixture especially the lithium
nitrate was removed in the process of heating Moreover the partially solidified sample in the
sample loading process can be re-homogenized in the first heating cycle [65-67] In figure 63
69 and 610 more than one endothermic peak was found The first smaller endothermic peak
refers to solid state phase transition of the salt mixture The second larger endothermic peak
refers to the melting of the salt Normally the onset temperature of transition is taken as the
experimental transition point for any metallic sample However in case of molten salts mixtures
since the thermal conductivity is low [68-74] the complete transition is ensured only at the peak
42
transition temperature The thermal gradient which exists due to the low thermal conductivity of
the salt results in internal heat flow which enhances the mixing in the salt Thus the transition
temperature is defined as the peak temperature of phase transition For salt No1 the small
endothermic peak happened before and was connected to the main peak which occurred at
39027K The first endothermic peaks for salt No 7 and 8 occurred at almost the same
temperature because of the similar composition for these two compounds Since the small
amount of magnesium nitrate and potassium nitrite contained in these two compounds the small
endothermic peak can hardly be related to these two components Obviously the rest three major
components must have something to do with the first peaks happened before the melting peaks
for both cases Each component among the major three ones were tested to find out any possible
solid phase transition peaks of them and the results shown in Table 63 which reveals that
lithium nitrate doesnt have any phase transition peak in solid state while potassium nitrate and
sodium nitrite both own the solid phase transformation peaks before their melting peaks
Table 63 Fusion and solid phase transition temperature for individual salts
System Tmp degC Ttrans degC ΔHfusion Jg ΔHtrans Jg
LiNO3 2550 - 3633 -
KNO3 3372 1332 1005 529
NaNO2 4311 4170 1119 880
The further investigation was carried out by running the KNO3-NaNO2 (550 wt and 238 wt )
binary compound with the very similar weight percentage as that in salt No 7 (546 wt and
237 wt) and salt No 8 (559wt and 239wt) By converting the weight percentage of the
studied binary system into 100 scale the weight fraction for sodium nitrate and potassium
nitrate can be rewritten as 698wt and 302wt The DSC plot for this binary system was
43
shown in fig 612 Although the solid transition and melting temperature were brought down by
adding lithium nitrate the shape of the plots in fig 69 and 610 are identical to that shown in fig
612 The enthalpy of solid state transformation of the binary salt was also converted to that in
both quaternary systems by using the weight fraction occupied by the binary system and the
comparable change of converted enthalpy between the binary system and two quaternary systems
indicates the relevance of the solid transition peaks in salt 7 and 8 to the combined effect of
potassium nitrate and sodium nitrite
Figure 612 DSC plot of 698wt KNO3- 302wt NaNO2 binary system
The similar analysis was applied to No1 salt to find out the reason for the presence of a
small peak adherent to the main melting peak before the melting point Sodium nitrate and
potassium nitrate binary system was synthesized based on the weight fraction of these two
constituent salts in No 1 salt DSC plot for the sodium nitrate-potassium nitrate binary system in
Fig 613 with the converted composition which is essentially same as that in the No1 ternary
system shows smooth heat flow curve before the melting peak which means the solid transition
peak in ternary is not simply relative to the binary system Assumption was made that the solid
44
phase transformation peak in the ternary salt is resulted from a multiple effect ie the
combination of one of the eutectic binary system involved in the ternary salt mixture and the
other binary system which is composed of the rest components The statement is verified that the
small peak in salt 1 is mainly caused by the solid phase transformation peak in lithium nitrate-
potassium nitrate eutectic binary system given the similar shape of the DSC plots in Fig 614
Since in salt No1 there is excess amount of sodium nitrate to form the lithium nitrate-sodium
nitrate binary system the rest sodium nitrate can interact with potassium nitrate and form new
sodium-potassium nitrate system which is shown in fig615 Besides a solid phase
transformation peak is observed in fig615 which has a very small area and won‟t change the
shape of phase transformation peak in fig614 when these two binary systems are combined and
form salt 1 The enthalpies of solid state transformation in two binary salts were also converted
to that in salt 1 by using the weight fractions occupied by both binary systems The difference
of the change of converted enthalpies between the lithium-potassium nitrate eutectic binary and
ternary system is filled by the binary mixture which is composed of the rest components sodium
nitrate-potassium nitrate The comparable converted values of enthalpy change between salt 1
and its two constituent binary systems further verify the assumption that the solid phase
transformation happened in salt 1 is mainly due to the combined effect of LiNO3-KNO3 eutectic
binary system and NaNO3-KNO3 binary system
45
Figure613 DSC plot of 270wt NaNO3-730wt KNO3 binary system
Figure614 DSC plot of 458wtLiNO3-542wtKNO3 binary system
46
Figure615 DSC plot of 460wt NaNO3-540wt KNO3 binary system
Unlike those discussed mixtures above salt No2 Salt No4 Salt No5 and Salt No6 have
only one relatively board melting peak and the heat flow curve before and after are very stable
Similarly there is no solid transformation peaks observed in salt No3 salt No7 and salt No8
However the heat flow after the melting peak in these cases are not stable and the main
endothermic peak is followed by a small hump which is considered to be the recrystallization
process once the compound entered into the liquid state When the process is finished the heat
flow curve returns to steady state
Heating rate is a significant parameter when collect the heat flow curves by using DSC
technique Fig 616(a) and Fig 616(b) illustrate the difference of melting point for salt No6 due
to the change of heating rate If the heating rate is 20oCmin the peak temperature and onset
temperature for the melting peak is 9669oC and 9221
oC respectively Once the heating rate is
decreased to 5oCmin these two temperatures will also be lowered to 9614
oC and 9190
oC The
difference is resulted from the diverse amount of thermal resistance between the testing sample
and the furnace inside the DSC instrument [75] Under higher heating rate the decisive thermal
47
resistance is raised due to the low thermal conductivity medium between the furnace and the
actual sample The insensitivity of gas heat conduction medium in DSC results each unit of
temperature increase on one side cannot have an immediate response on the other side of the gas
Consequently the sample holder which is connected the furnace has a higher temperature than
that inside the sample In this condition the value of temperature profile collected as the sample
holder temperature is larger than the actual temperature The deviation will be much smaller
when the heating rate is reduced In the case the thermal resistance will be decreased because of
the lower temperature gradient of the gas medium in the heating process As a result of that the
collected temperature from the sensor attached to the sample holder will be very close to the
actual temperature inside the testing sample
Figure 616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 20oCmin
heating rate
48
Figure 616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 5oCmin
heating rate
Besides the difference of temperature while using higher and lower heat rate the solution
of DSC will also be affected by different heating rate Fig 617(a) shows the DSC plot for salt
No 7 using the heating rate as 5oCmin and the DSC plot in Fig 617(b) is collected under the
heating rate as 20oCmin It can be observed that in the lower heating rate two small separated
peaks can be viewed as two parts of the solid phase transformation process while in Fig 617(b)
two small peaks before the melting peak merge and present as a board hump The qualification
of resolution can be executed by the term named resolution factor RMKE which is calculated as
the ratio of the peak heat flow value of the separated peaks to that of the concave point between
two peaks The equation for determining RMIKE is given in Eq 27 [76 77]
RMIKE =hpeakhmin [27]
49
Figure 617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 5oCmin
heating rate
Figure 617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 20oCmin
heating rate
In the case of lower heating rate the RMKE is determined to be 15 and the value for higher
heating rate is not available because the concave point of heat flow doesn‟t exist from
Fig617(b) Since the higher RMKE value indicates better resolution it can be stated that the
50
lower heating rate also results in greater sensitivity of the equipment to pick up any small
endothermic peaks
Besides the down-selected 9 compounds some more salt mixtures were also tested Most
of them were not selected to the final candidate for the thermal energy storage application
because of their higher melting point Table 64 gives some of the trial systems measured with
DSC technique It is illustrated that the melting points of mixtures with lower or even no content
of lithium nitrate turn out to be higher than those with sufficient amount of lithium nitrate For
most of the mixtures with melting point lower than 120oC the amount of lithium nitrate should
be larger than 81wt Also all of the systems in table 64 with lithium nitrate less than 15wt
have melting point higher than 140oC Based on the observation above it is concluded that the
lithium nitrate can be used as an additive to bring the melting point down for thermal energy
storage systems
51
Table 64 Melting points of candidate systems as function of temperatures
System Composition (wt)
Onset
Temp
Peak
Temp
(oC) (
oC)
LiNO3 ndash NaNO3 ndash KNO2 107 459 434 890 910
LiNO3 - KNO3 - NaNO2 196 564 241
1024 1046
LiNO3 - NaNO3 - KNO3 - KNO2 90 423 337 151
930 960
LiNO3 - NaNO3 - NaNO2 - KNO2 81 454 65 401
900 910
LiNO3 - KNO3 - NaNO2 - KNO2 193 546 237 24
992 1003
LiNO3 - KNO3 - NaNO2 ndash Mg(NO3)2 193 559 238 09
1010 1020
LiNO3 - NaNO3 - KNO3 - Mg(NO3)2
- MgK 154 172 324 83 267 834 892
LiNO3 - NaNO3 - KNO2 ndash Ca(NO3)2 14 390 333 263
1250 1470
NaNO3 - KNO3 - NaNO2 - KNO2 425 163 71 341
1407 1447
NaNO3 - KNO3 - KNO2 ndash Mg(NO3)2 432 146 380 42
1386 1421
NaNO3 - NaNO2 - KNO2 - Ca(NO3)2 451 92 410 48
1150 1390
LiNO3 - NaNO3 - NaNO2 - KNO2 -
Ca(NO3)2 15 393 37 323 232 1380 1480
LiNO3 - NaNO3 - KNO2 - Ca(NO3)2 -
Mg(NO3)2 14 379 313 275 20 1339 1534
62 Heat capacity determination
621 Heat capacity calibration
DSC was also calibrated for the heat capacity measurement Lithium nitrate sodium
nitrate and potassium nitrate were examined for the heat capacities from room temperature to
upper limit temperature for the instrument In liquid state the heat capacity values for each salt
can be fit to straight line with trace amount of increasing trend Since the temperature range from
the onset temperature of liquid state to the upper limit of DSC is relatively small the heat
capacity values for pure individual salts can be viewed as constants The comparison between the
theoretical and experimental heat capacity data is given in Table 65 Except lithium nitrate the
52
experimental heat capacities data for the rest two systems are almost same as the literature Even
for lithium nitrate which demonstrates the biggest difference from the literature data the 28
vibration is still within a reasonable range
Table 65 Calibration data of heat capacities with different samples
Sample Lit Cp Expt Cp
JgK JgK
LiNO3 218 212
NaNO3 169 167
KNO3 140 139
622 Results
The materials used in the heat capacity measurements are the same as those in the melting
point experiments Molar heat capacities of the all compound were measured by the DSC
equipment from room temperature to 62315 K The heat flow is recorded as a function of
temperature in ldquoiso-scan-isordquo steps at intervals of 20 K The bdquoiso stage‟ refers to isothermal
holding at a particular temperature bdquoscan stage‟ refers to the heat flow recording at a heating rate
of 5 K min1
up to a an increment of 25 K followed by another isothermal holding stage This is
a standard procedure followed in the measurement of heat capacity of materials using the DSC
equipment [63 64] This procedure of heat capacity measurement has two advantages (i) any
heat fluctuations during the recording are avoided by the isothermal steps and (ii) any phase
transition can be highlighted by the choice of temperature range The absolute heat flow to the
sample is determined by subtracting the heat flow collected by running a baseline curve with an
empty pan Because the heat capacity measurement in the heating process corresponds to
53
collecting the value of required heat flow at each temperature all the heat capacity plots have the
same shape with that of heat flow in the melting point measurements Take the heat capacity plot
of LiNO3-NaNO3-KNO3 ternary system as an instance which is shown in fig 618 the heat
capacity curve also has two different peaks The first little peaks corresponds to one occurs at
39027K which was observed in fig 63 the second large and sharp peak happened right after the
small one is prevalent to the endothermic peak with the peak temperature as 39027 K Similarly
after the phase transformation the heat capacity in liquid state becomes very stable and increase
with temperature linearly with little slope
Fig 618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system as function of
temperature
The heat capacity change as function of temperature for salt No1 was illustrated in fig
619 Based on the trend of heat capacity in the liquid state any value for the system in the liquid
can be extrapolated The expressions for heat capacity in liquid state for the new molten salt
systems were discussed and given in the next sectionTable66 shows the specific heat capacity
54
of the all the selective compounds measured at 62315 K and extrapolated at 77315K Besides
the molar heat capacities at 77315K are given in Table 66 of all the salts
Fig 619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K
Table 66 Heat capacity of selected new TES molten salt mixtures
System Expt (62315K) Extrapolated(77315K) Extrapolated(77315K)
Cp JgK Cp JgK Molar Cp JmolK
Salt 1 153 170 1521
Salt 2 143 168 1515
Salt 3 148 155 2183
Salt 4 153 166 1411
Salt 5 153 170 1440
Salt 6 151 163 1435
Salt 7 156 167 1443
Salt 8 155 168 1410
Salt 9 161 170 1937
55
623 Thermodynamic properties
The standard thermodynamic properties such as entropy enthalpy and Gibbs energy for
salt mixtures are determined from the experimental data of melting point and heat capacity in the
temperature range of the present study and expression for determining these properties are given
in equation 28-30 In thermodynamics all these three properties are related to heat capacity and
its variances with temperature In the studied temperature range (29815K-62315K) they can be
described as expression includes heat capacity
[28]
[29]
[30]
Where Tt is the solid transformation temperature Tmp is the melting point ΔHt is enthalpy of
solid phase transformation and ΔHfusion is enthalpy of fusion The standard thermodynamic
properties entropy enthalpy and Gibbs energies as function of temperature for each compound
are expressed in the following section
6231 LiNO3-NaNO3-KNO3 (Salt 1)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3
compound (i) solid state 1 (32315-38415) K (ii) liquid state (40315-62315) K Accordingly
56
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62311 Heat capacity of solid state 1 (29815-38415) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the solid state 1 in the
temperature range of 29815 to 38415 K is fit to a second order polynomial equation Eqn (31)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[31]
( ) K
R2 = 0982
62312 Heat capacity of liquid state (40315-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a linear equation Eqn (32) gives the linear
equation along with the least square fit parameter (R2) in the temperature range for the liquid
state of the compound
JKmol [32]
57
R2 = 0947
Heat capacity data of the LiNO3-NaNO3-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62313 Thermodynamic properties of solid state 1(29815-38415) K
JKmol [33]
Jmol [34]
[35]
Jmol
62314 Thermodynamic properties of liquid state 2(40315-62315) K
[36]
58
JKmol
Jmol [37]
[38]
Jmol
Among the equations above equation (33)-(35) refer to the thermodynamic properties for
solid state equations (36)-(38) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature ranges for solid and liquid state are
given in Table A1 and A2 in appendix A respectively with the corresponding heat capacity as
function of temperature
6232 NaNO3-NaNO2-KNO3 (Salt 2)
The heat capacity data can be divided into two sections for NaNO3-NaNO2-KNO3
compound (i) solid state 1 (32315-39215) K (ii) liquid state (41315-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62321 Heat capacity of solid state 1 (29815-39215) K
59
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the solid state in the
temperature range of 29815 to 39215 K is fit to a second order polynomial equation Eqn (39)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[39]
( ) K
R2 = 0978
62322 Heat capacity of liquid state (40315-62315) K
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a second order polynomial equation Eqn (40)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[40]
R2 = 0941
60
Heat capacity data of the NaNO3-NaNO2-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62323 Thermodynamic properties of solid state 1(29815-39215) K
JKmol [41]
Jmol [42]
[43]
Jmol
62324 Thermodynamic properties of liquid state 2(40315-62315) K
JKmol [44]
61
Jmol [45]
[46]
Jmol
Among the equations above equation (41)-(43) refer to the thermodynamic properties for
solid state equations (44)-(46) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table B1 and B2 in appendix B respectively with the corresponding heat capacity as
function of temperature
6233 LiNO3-NaNO3 -KNO3-MgK (Salt 3)
The heat capacity data can be divided into two sections for LiNO3-NaNO3 -KNO3-MgK
compound (i) solid state 1 (29815-36415) K (ii) liquid state (42115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62331 Heat capacity of solid state 1 (29815-36415) K
62
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the solid state in the
temperature range of 29815 to 36415 K is fit to a second order polynomial equation Eqn (47)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[47]
( ) K
R2 = 0995
62332 Heat capacity of liquid state (42115-62315) K
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the liquid state in the
temperature range of 42115 to 62315 K is fit to a second order polynomial equation Eqn (48)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[48]
R2 = 0963
63
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
62333 Thermodynamic properties of solid state 1(29815-36415) K
JKmol [49]
Jmol [50]
[51]
Jmol
62334 Thermodynamic properties of liquid state 2(42115-62315) K
64
JKmol [52]
Jmol [53]
[54] [29]
Jmol
Among the equations above equation (49)-(51) refer to the thermodynamic properties for
solid state equations (52)-(54) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table C1and C2 in appendix C respectively with the corresponding heat capacity as
function of temperature
6234 LiNO3-NaNO3-KNO3-NaNO2 (Salt 4)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-NaNO2
compound (i) solid state 1 (29815-36315) K (ii) liquid state (38115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62341 Heat capacity of solid state 1 (29815-36315) K
65
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the solid state in the
temperature range of 29815 to 36315 K is fit to a second order polynomial equation Eqn (55)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[55]
( ) K
R2 = 0995
62342 Heat capacity of liquid state (38115-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the liquid state in the
temperature range of 38115 to 62315 K is fit to a second order polynomial equation Eqn (56)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[56]
R2 = 0972
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
66
62343 Thermodynamic properties of solid state 1(29815-36315) K
JKmol [57]
Jmol [58]
[59]
Jmol
62344 Thermodynamic properties of liquid state 2(38115-62315) K
JKmol [60]
Jmol [61]
67
[37]
Jmol [62]
Among the equations above equation (57)-(59) refer to the thermodynamic properties for
solid state equations (60)-(62) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table D1 and D2 in appendix D respectively with the corresponding heat capacity as
function of temperature
6235 LiNO3-NaNO3-NaNO2-KNO3-KNO2 (Salt 5)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-NaNO2-KNO3-
KNO2 compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62351 Heat capacity of solid state 1 (29815-35915) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
in the temperature range of 29815 to 35915 K is fit to a second order polynomial equation Eqn
(63) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
68
[63]
( ) K
R2 = 0996
62352 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the liquid
state in the temperature range of 37515 to 62315 K is fit to a second order polynomial equation
Eqn (64) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[64]
R2 = 0969
Heat capacity data of the LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62353 Thermodynamic properties of Solid state 1(29815-35915) K
JKmol [65]
69
Jmol [66]
[67]
Jmol
62354 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [68]
Jmol [69]
[45]
Jmol [70]
70
Among the equations above equation (65)-(67) refer to the thermodynamic properties for
solid state equations (68)-(70) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table E1 and E2 in appendix E respectively with the corresponding heat capacity as
function of temperature
6236 LiNO3-NaNO3-KNO3-KNO2 (Salt 6)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-KNO2
compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62361 Heat capacity of solid state 1 (29815-36515) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the solid state in the
temperature range of 29815 to 36515 K is fit to a second order polynomial equation Eqn (71)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[71]
( ) K
R2 = 0998
71
62362 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the liquid state in the
temperature range of 37515 to 62315 K is given in Table 20 The data is fit to a second order
polynomial equation Eqn (72) gives the linear equation along with the least square fit parameter
(R2) in the temperature range for the liquid state of the compound
[72]
R2 = 0953
Heat capacity data of the LiNO3-NaNO3-KNO3-KNO2 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62363 Thermodynamic properties of solid state 1(29815-35915) K
JKmol [73]
Jmol [74]
72
[75]
Jmol
62364 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [76]
Jmol [77]
Jmol [78]
Among the equations above equation (73)-(75) refer to the thermodynamic properties for
solid state equations (76)-(78) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
73
given in Table F1 and F2 in appendix F respectively with the corresponding heat capacity as
function of temperature
6237 LiNO3-KNO3-NaNO2-KNO2 (Salt 7)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62371 Heat capacity of solid state 1 (29815-35415) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 1 in
the temperature range of 29815 to 35415 K is fit to a second order polynomial equation Eqn
(79) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[79]
(29815-35415) K
R2 = 0993
62372 Heat capacity of solid state 2 (36215-37315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 2 in
the temperature range of 36215 to 37315 K is fit to a second order polynomial equation Eqn
74
(80) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 2 of the compound
[80]
R2 = 0977
62373 Heat capacity of liquid state (37915-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the liquid state in the
temperature range of 37915 to 62315 K is fit to a linear equation Eqn (81) gives the
polynomial equation along with the least square fit parameter (R2) in the temperature range for
the liquid state of the compound
[81]
R2 = 0961
Heat capacity data of the LiNO3-KNO3-NaNO2-KNO2 compound in the two solid states
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62374 Thermodynamic properties of solid state 1(29815-35415) K
75
JKmol [82]
Jmol [83]
[84]
Jmol
62375 Thermodynamic properties of solid state 2(36215-37315) K
JKmol [85]
Jmol [86]
76
[87] [62]
Jmol
62376 Thermodynamic properties of liquid state (37915-62315) K
JKmol [88]
Jmol [89]
Jmol [90]
Among the equations above equation (82)-(84) refer to the thermodynamic properties for
solid 1 equation (85)-(87) refer to the thermodynamic properties for solid 2 equations (88)-(90)
refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy values
77
in the studied temperature range for solid 1 solid 2 and liquid state are given in Table G1-G3 in
appendix G respectively with the corresponding heat capacity as function of temperature
6238 LiNO3-KNO3-NaNO2-Mg(NO3)2 (salt 8)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62381 Heat capacity of solid state 1 (29815-33715) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid
state 1 in the temperature range of 29815 to 33715 K is fit to a second order polynomial
equation Eqn (91) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the solid state 1 of the compound
[91]
(29815-33715) K
R2 = 0994
62382 Heat capacity of solid state 2 (36115-36415) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid state 2
in the temperature range of 36115 to 36415 K is given in Table 4 The data is fit to a second
78
order polynomial equation Eqn (92) gives the polynomial equation along with the least square
fit parameter (R2) in the temperature range for the solid state 2 of the compound
[92]
R2 = 0992
62383 Heat capacity of liquid state (41115-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the liquid state in
the temperature range of 41115 to 62315 K is given in Table 5 The data is fit to a linear
equation Eqn (93) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the liquid state of the compound
[93]
R2 = 0934
Heat capacity data of the LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the two solid
states follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62384 Solid state 1(29815-35415) K
79
JKmol [94]
Jmol [95]
[96]
Jmol
62385 Solid state 2(36115-36415) K
JKmol [97]
80
Jmol [98]
[99] [74]
Jmol
62386 Liquid state (41115-62315) K
JKmol [100]
Jmol [101]
Jmol [102]
Among the equations above equation (94)-(96) refer to the thermodynamic properties for
solid 1 equation (97)-(99) refer to the thermodynamic properties for solid 2 equations (100)-
(102) refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy
81
values in the studied temperature range for solid 1 solid 2 and liquid state are given in Table H1
and H2 in appendix H respectively with the corresponding heat capacity as function of
temperature
6239 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK(Salt 9)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-
Mg(NO3)2-MgK compound (i) solid state 1 (29815-35315) K (ii) liquid state (39115-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62391 Heat capacity of solid state 1 (29815-35315) K
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state in the temperature range of 29815 to 35315 K is fit to a second order polynomial equation
Eqn (103) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[103]
( ) K
R2 = 0996
62392 Heat capacity of liquid state (39115-62315) K
82
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the liquid
state in the temperature range of 39115 to 62315 K is fit to a second order polynomial equation
Eqn (104) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[104]
R2 = 0951
Heat capacity data of the LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62393 Solid state 1(29815-35315) K
JKmol [105]
Jmol [106]
83
[107]
Jmol
62394 Liquid state 2(39115-62315) K
JKmol [108]
Jmol [109]
[110]
Jmol
Among the equations above equation (105)-(107) refer to the thermodynamic properties
for solid state equations (108)-(110) refer to thermodynamic properties of the liquid The
entropy enthalpy and Gibbs energy values in the studied temperature range for solid and liquid
state are given in Table I1 and I2 in appendix I respectively with the corresponding heat
capacity as function of temperature
84
624 Discussion of Gibbs energy change for molten salts
The Gibbs energy change data as function of temperature for 9 systems are given in fig
620 and the values at 62315K are shown in Table 67 Every system demonstrates continuous
curve throughout the whole studied temperature range Most of systems have similar Gibbs
energy change values for each temperature spot due to the comparable compositions and
properties of constituent salts However salt 3 and salt 9 Both of these salts have certain
amount of MgKN compound which presents large absolute amount of change of Gibbs energy in
the same studied temperature range [66] Since the change of Gibbs energy for multi-component
mixture is relevant to that of each constituent salt the large absolute value of ΔG of MgKN
mainly contributes to the largely negative value of salt 3 and salt 9 shown in fig 620 Besides
it is observed that most systems contain nitrite salts present lower absolute value of Gibbs energy
change For example salt 1 doesn‟t include any nitrite salt and has a relatively high absolute
value of Gibbs energy change as 1704kJmol while other systems having nitrite salts show lower
value varies from 1372kJmol to 1592kJmol
85
Fig 620 Change of Gibbs energy as function of temperature for molten salt systems
Table 67 Change of Gibbs energy values at 62315K for molten salt systems
SNo System ΔG(kJmol)
1 LiNO3-NaNO3-KNO3 1704
2 NaNO3- NaNO2- KNO3 1372
3 LiNO3- NaNO3- KNO3- MgKN 2807
4 LiNO3- NaNO3- KNO3- NaNO2 1443
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1441
6 LiNO3-NaNO3-KNO3-KNO2 1570
7 LiNO3-KNO3-NaNO2-KNO2 1592
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1583
9 LiNO3-NaNO3-KNO3-Mg(NO3)2 -MgKN 2217
86
63 Density determination
631 Density calibration
Several pure molten salts are used to calibrate the density measurement set-up before the
actual density measurement All the density values decrease as function of temperature in the
liquid state and follow the same linear equations as described in eq 4 The experimental values
at 350oC for KNO3 NaNO3 and LiNO3 are selected to compare with the literature data at the
same temperature The results are shown in Table 68 Based on the comparison of the literature
data and the experimental data the variation of density for molten nitrate salt is within in 4
Table 68 Calibration of density measurements with different pure nitrate salts
Sample Literature density Experimental density
gcm3 gcm
3
LiNO3 1727 1701
NaNO3 2066 2144
KNO3 1860 1855
632 Results and discussions
The density result of the salt as function of temperature is plotted for all the salts in Figure
621 and Figure 622 It is observed that the temperature dependence of density above the
melting point is different from that in solid state As known in solid state the density of salt has
an exponential relation with temperature while in these liquid cases the density values have
linearly dependence with temperature The stable variation as function of temperature allows the
extrapolation of density at even higher temperature The regression analysis is performed to get
the coefficient used for describing eq 4 and the results for the coefficients are shown in
87
Table69 [78-80] It is observed that the change of composition is implied on the coefficient A
which indicates the initial point at 150oC The temperature dependence coefficient B doesn‟t
change much with composition which may be mainly affected by the group of anion and cation
Table 69 Coefficient A and B for density determination of salt 1-salt 9
Salt No System A Btimes10
3
(gcm3) (gcm
3degC)
1 LiNO3-NaNO3-KNO3 2032 0493
2 NaNO3- NaNO2- KNO3 2081 0570
3 LiNO3- NaNO3- KNO3-MgKN 2055 0526
4 LiNO3- NaNO3- KNO3- NaNO2 2033 0520
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 2018 0485
6 LiNO3-NaNO3-KNO3-KNO2 2060 0554
7 LiNO3-KNO3-NaNO2-KNO2 2048 0554
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 2044 0524
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 2060 0566
Figure 621 The densities of the salt 1-salt 5 as function of temperature
88
In figure 621 all the density values are clustered around 198gcm3 at 150
oC to
186gcm3 at high temperature end and the deviation of density between all the mixtures is within
in 0047g cm3 Among all the salt mixtures the NaNO3-NaNO2-KNO3 ternary system
demonstrates the highest density value throughout the studied temperature range and LiNO3-
NaNO3-KNO3 ternary system LiNO3- NaNO3-KNO3-NaNO2 quaternary system and LiNO3-
NaNO3-KNO3-NaNO2-KNO2 quinary system show densities at the bottom side of Fig 621 For
salt 2 which doesn‟t contain any lithium nitrate the density at every selected temperature spot
is obviously higher than that of salt 1 4 and 5 which have large amount of lithium nitrate
Moreover the salt 3 which contains the relatively small amount of lithium nitrate stays in
between of salt 1 and salt 2 This comparison illustrates that the addition of lithium nitrate has
an offsetting effect on density for molten salt and it is consistent with previous literature reports
[81] The four systems presented in figure 622 also show even closer density values in the
studied temperature range Similarly salt 6 which contains the least lithium nitrate has the
largest density Salt 7 and salt 8 have almost same composition for the three dominating
components as a result of that the density curves for both mixtures are determined by the same
regression coefficient A and B Moreover the larger amount of lithium nitrate involved in these
two salt mixtures contributes to the lower density given in figure622 which further verifies the
significantly offsetting effect of lithium nitrate on density
89
Figure 622 The densities of the salt 6-salt 9 as function of temperature
The salt mixtures with maximum and minimum amount of lithium nitrate were plotted and
compared with equimolar NaNO3-KNO3 binary system and pure KNO3 salt in Fig623 [82 83]
It is observed that the NaNO3-KNO3 binary system has very similar density value to that of salt
2 because of the analogous type and composition of component in both salts The density of
pure KNO3 is slightly lower than the binary salt mixture which indicates the density of NaNO3 is
close to but higher than KNO3 in the studied temperature range Salt 1 shows the lowest density
in Fig623 due to the offsetting effect on density caused by lithium nitrate which has been
discussed above
90
Figure 623 Density of the salt 1 salt 2 as function of temperature compared to the
equimolar NaNO3-KNO3 binary system and pure KNO3
64 Thermal energy storage density of molten salts
The energy density which is considered as one of the most significant parameters of TES
application can be evaluated by calculation based on the measured density heat capacity and
working temperature range The equation of the thermal energy storage density (E) at working
temperature of 500oC is expressed in equation 111
E = Cp (500-Tm) [111]
Where Cp and are extrapolated heat capacity and density at 500oC respectively Tm is
melting point for salt mixture The extrapolation of density and heat capacity is based on the
linear temperature dependence for both parameters in molten state and the values are shown in
Table 610
91
Table 610 Extrapolated value of density and heat capacity at 500oC of salt 1-salt 9
Salt
No System
Density Heat Capacity
(gmL) (JgK)
1 LiNO3-NaNO3-KNO3 1785 170
2 NaNO3- NaNO2- KNO3 1796 168
3 LiNO3-NaNO3-KNO3-MgK 1773 155
4 LiNO3- NaNO3- KNO3- NaNO2 1792 166
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1796 170
6 LiNO3-NaNO3-KNO3-KNO2 1783 163
7 LiNO3-KNO3-NaNO2-KNO2 1771 167
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1782 168
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 1777 170
The calculated energy density for each salt is given in Table 611 compared with that of
solar salt (NaNO3-KNO3) All the new synthesized salt mixtures have significantly higher energy
density than solar salt and salt 3 shows the highest energy density among the new salts
Although salt 1 has higher heat capacity and good melting point the energy density is still the
lowest among new salt mixtures given by the effect of low density The conclusion can be drawn
from these observations that the energy density is a property affected by multiple parameters and
every part plays an important role in determining the efficiency of energy storage of salt
mixtures
92
Table 611 Energy density of salt 1-salt 9 compare to solar salt
The gravimetric storage density of new molten salts are listed in Table 612 and compared
with those different storage systems in fig 624 It is found that in the parabolic trough working
temperature range the gravimetric storage densities of new molten salts are located on the higher
side Even though some reported sensible energy storage liquids have larger gravimetric density
values than the new salts the maximum working temperatures reveal the instable working
condition at 500oC Taking conversion efficiency thermal stability and gravimetric storage
density into considerations the new molten salts are the most suitable choices of the sensible
heat storage for parabolic trough application
Salt No System Energy Density
500degC (MJm3)
0 NaNO3- KNO3 756
1 LiNO3-NaNO3-KNO3 1162
2 NaNO3- NaNO2- KNO3 1135
3 LiNO3-NaNO
3-KNO
3-MgKN 1099
4 LiNO3- NaNO
3- KNO
3- NaNO
2 1189
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1232
6 LiNO3-NaNO3-KNO3-KNO2 1174
7 LiNO3-KNO3-NaNO2-KNO2 1183
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1192
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 1242
93
Fig 624 Gravimetric storage density comparison of different energy storage systems as
function of temperature
Table 612 Gravimetric storage densities for solar salt and new molten salts
Salt
No System
Gravimetric Storage Density
500degC (kJkg)
0 NaNO3- KNO3 404
1 LiNO3-NaNO3-KNO3 560
2 NaNO3- NaNO2- KNO3 533
3 LiNO3-NaNO
3-KNO
3-MgKN 575
4 LiNO3- NaNO
3- KNO
3- NaNO
2 612
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 595
6 LiNO3-NaNO3-KNO3-KNO2 594
7 LiNO3-KNO3-NaNO2-KNO2 604
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 610
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 649
94
CHAPTER 7
CONCLUSION
The melting points of new molten salts were experimentally determined using DSC
Different from metals the melting point was chosen as the peak temperature rather than onset
temperature of the endothermic peak due to the low thermal conductivity and broad phase
transition range of the molten nitride salt mixture All of the nine new molten salts have melting
points from 89oC to 124
oC which are much lower than current sodium-potassium binary solar
salt Some systems such as salt No1 No7 and No8 have solid phase transformation observed
from the DSC plots It is found that the phase transformations of salt No 7 and No 8 are mainly
contributed to the KNO3-NaNO2 binary system while the small solid transformation peak of salt
No1 is resulted from the combined effect of the KNO3-LiNO3 eutectic binary system involved in
the ternary salt and another binary system which is composed of the rest components The
heating rate of DSC was revealed as a significant parameter for the any endothermic peak
determination When using lower heating rate the thermal resistance between the studied sample
and the furnace will be minimal and the resolution of peak detection will be enhanced
The heat capacities of all the multi-component salts (1 to 9) were determined using DSC
and found varying from 143 to 161 JgK at 350oC The heat capacity in the liquid state
demonstrates linear increase trend as function of temperature On the basis of that the heat
capacity was extrapolated to parabolic trough operating temperature of 500oC Besides heat
capacity data as function of temperature are fit to polynomial equation and thermodynamic
95
properties like enthalpy entropy and Gibbs energies of the compound as function of temperature
are subsequently deduced
Experimental measurements of density of multi-component systems were conducted as
function of temperature in their liquid state In liquid state the density values decrease linearly
as temperature increases The results of those mixtures were compared to the solar salt and
individual constituent salts The comparison demonstrates that the addition of lithium nitrate
lowers the density which is consistent with the observation that lithium nitrate has the lowest
density among all the individual salts in the studied temperature range On the basis of densities
heat capacities and the melting points energy storage density for all the new salts were
calculated and compared to the binary solar salt Among all the new molten salt systems
LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN quinary system (salt 9) presents the largest thermal
energy storage density as well as the gravimetric density values Moreover the larger thermal
energy storage as well as gravimetric storage densities compared to the solar salt indicate the
better energy storage capacities of new salts for solar power generation systems
96
REFERENCES
[1] JF Manwell JG McGowan and AL Rogers Wind Energy Explained-Theory Design and
Application second edition John Wiley and sons Ltd UK 2009
[2] MJ Pasqualetti Morality space and the power of wind-energy landscapes Geographical
Review 90 2000 381-394
[3] DG Fink and HW Beaty Standard Handbook for Electrical Engineers Eleventh Edition
McGraw-Hill New York 1978
[4] R Bertani Geothermal Energy An Overview on Resources and Potential Proceedings of the
International Conference on National Development of Geothermal Energy Use 2009 Slovakia
[5] TA Volk LP Abrahamson EH White E Neuhauser E Gray C Demeter C Lindsey J
Jarnefeld DJ Aneshansley R Pellerin and S Edick Developing a Willow Biomass Crop
Enterprise for Bioenergy and Bioproducts in the United States Proceedings of Bioenergy
2000 October 15-19 2000 Buffalo New York USA
[6] M Asplund N Grevesse and AJ Sauval The new solar abundances-Part I the
observations Communications in Asteroseismology 147 2006 76-79
[7] DRWilliams Sun Fact Sheet NASA 2004
httpnssdcgsfcnasagovplanetaryfactsheetsunfacthtml
[8] U Herrmann Survey of Thermal Energy Storage for Parabolic Trough Power Plants Journal
of Solar Energy Engineering 124 2002 145-152
[9] Rocket Research Company Chemical energy storage for solar thermal conversion SAND79-
8198 Livermore Sandia National Laboratories 1979
97
[10] A Steinfeld and R Palumbo Solar thermochemical process technology Encyclopedia of
Physical Science and Technology 2001 237-256
[11] EA Fletcher Solar thermal processing a review Journal of Solar Energy Engineering
2001 63-74
[12] R W Bradshaw and Nathan P Siegel Molten Nitrate Salt Development for Thermal
Energy Storage in Parabolic Trough Solar Power Systems of the Energy Sustainability 2008
Conference August 10-14 2008 Jacksonville Florida USA
[13] B Kelly H Price D Brosseau and D Kearney Adopting NitrateNitrite Salt Mixtures as
the Heat Transport Fluid in Parabolic Trough Power Plants Proceedings of the Energy
Sustainability 2007 Conference June 27-30 2007 Long Beach CA
[14] H Reilly and G Kolb Evaluation of Molten Salt Power Tower Technology Based on
Experience at Solar Two SAND2001-3674 Sandia National Laboratories 2001
[15] T Wendelin ldquoParabolic Trough VSHOT Optical Characterization in 2005-2006rdquo NREL
wwwnrelgovdocsfy06osti40024pdf
[16] RB Diver C Andraka S Rawlinson V Goldberg and G Thomas The Advanced Dish
Development System Project ASME Proceedings of Solar Forum 2001 Washington DC
[17] S D Odeh G L Morrison and M Behnia Modelling of parabolic trough direct steam
generation solar collectors Solar Energy 62 1998 396-406
[18] V Heinzel H Kungle and M Simon Simulation of a parabolic trough collector ISES
Solar World Congress Harare Zimbabwe 1-10
[19] S D Odeh G L Morrison and M Behnia Modeling of Parabolic Trough Direct
Generation Solar Collectors Solar Energy 62 1998 395-406
[20] Ezzat Optimum Working Fluids for Solar Powered Rankine Cycle Cooling of Buildings
Solar energy 25 1980 235-241
98
[21] R G Reddy Ionic Liquids How well do we know them editorial Journal of Phase
Equilibria and Diffusion 27 2006 210-211
[22] M Zhang and R G Reddy Application of [C4min][Tf2N] Ionic Liquid as Thermal
Storage and Heat Transfer Fluids editor J Weidner ECS Transactions 2 (28) 2007 27-32
[23] M Zhang and R G Reddy Evaluation of Ionic Liquids as Heat Transfer Materials in
Thermal Storage Systems Energy Energy Materials editors F Dogan M Awano D Singh
and B Tuttle ASM International Materials Park Ohio USA MSampT‟07 2007 151-160
[24] R G Reddy Novel Applications of Ionic Liquids in Materials Processing Advanced
Structural and Functional Materials Design 2008 Journal of Physics Conference Series (JPCS)
165 2009 1-6
[25] RW Bradshaw and DE Meeker High-temperature stability of ternary nitrate molten
salts for solar thermal energy systems Solar Energy Materials 21 1990 51-60
[26] AS Trunin Designing and investigations of salt systems for solar energy utilization
Utilization of sun and other radiation sources in materials research Kiev Naukova Dumka 1983
p 228-38
[27] D J Rogers and G J Janz Melting-crystallization and premelting properties of sodium
nitrate-potassium nitrate Enthalpies and heat capacities Journal of Chemical and Engineering
Data 27 1982 424-428
[28] D Kearney U Herrmann P Nava and B Kelly Assessment of a molten salt heat transfer
fluid in a parabolic trough solar field Journal of Solar Energy Engineering 125 2003 170-176
[29] Q Peng J Ding X Wei J Yang and X Yang The preparation and properties of multi-
component molten salts Applied Energy 87 2010 2812-2817
[30] E M Levin C R Robbins and H F McMordie Phase Diagrams for Ceramists American
Ceramic Society 1964
[31] J C Oxley J L Smith E Rogers and M Yu Ammonium nitrate thermal stability and
explosivity modifiers Thermochimica Acta 384 2002 23-45
99
[32] LG Marianowski and HC Maru Latent heat thermal energy storage systems above
4508oC Proceedings of 12th intersociety energy conversion engineering conference 1977 55-
66
[33] HC Maru JF Dullea A Kardas L Paul LG Marianowski E Ong et al Molten salts
energy storage systems Chicago Final Report of the Institute of Gas Technology 1978
[34] WM Philips and JW Stears Advanced latent heat of fusion thermal energy storage for
solar power stations Proceedings of 20th intersociety energy conversion engineering conference
2 1985 384-391
[35] KE Mayo Heat source systems USA Patent 3605720 1971
[36] JI Eichelberger and HD Gillman Investigation of metal fluoride thermal energy storage
material Proceedings of 12th intersociety energy conversion engineering conference 1977 567-
574
[37] GR Heidenreich and MB Parekh Thermal energy storage for organic Rankine cycle solar
dynamic space power systems Proceedings of 21st intersociety energy conversion engineering
conference 2 1986 791-797
[38] IK Garkushin AC Trunin TT Miftakhov and MA Dibirov Salt heat storage
composition USSR Patent 1036734 1983
[39] W M Philips and J W Stears Advanced latent heat of fusion thermal energy storage for
solar power stations In Proceedings of 20th intersociety energy conversion engineering
conference 2 1985 384-391
[40] Y Takahashi M Kamimoto Y Abe R Sakamoto K Kanari and T Ozawa Investigation
of latent heat-thermal energy storage materials IV Thermoanalitical evaluation of binary eutectic
mixtures of NaOH with LiOH or KOH Thermochim Acta 121 1987 193-202
[41] C E Birchenall and A F Riechman Heat storage in eutectic alloys Metall Trans A
11A(8) 1980 1415-1420
100
[42] Y Takahashi R Sakamoto and M Kamimoto Heat capacities and latent heats of LiNO3
NaNO3 and KNO3 International Journal of Thermophysics 9(6) 1988 1081-1090
[43] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate Mixtures
Journal of Chemical Engineering Data 8(3) 1963 469
[44] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical Engineering Data 6 (4) 1961 493
[45] GF Petersen WA Ewing and G P Smith Densities of Some Salt Mixtures Journal of
Chemical Engineering Data 6 (4) 1961 540
[46] G J Janz and M R Lorenz Precise Measurement of Density and Surface Tension at
Temperatures up to 1000degC in One Apparatus Review of Scientific Instruments 31 (1) 1960
18-23
[47] G J Janz C B Allen N P Bansal R M Murphy and R P Tomkins Physical Properties
Data Compilations Relevant to Energy Storage II Molten Salts Data on Single and Multi-
Component Salt Systems National Bureau of Standards NSRDS-NBS 61 Part II April 1979
[48] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation Equations
for Critically Evaluated Density Surface Tension Electrical Conductance and Viscosity Data
Journal of Physical and Chemical Reference Data 17 1988 2
[49] A T Ward and G J Janz Molten Carbonate Electrolytes Electiral Conductance Density
and Surface Tension of Binary and Ternary Eleclrochimica Acta 10 1965 849-857
[50] Y Takahashi R Sakamoto and MKamimoto Heat Capacities and Latent Heat of LiNO3
NaNO3 amp KNO3 International Journal of Thermophysics 9 1998 1081-1090
[51] R W Carling Heat capacities of NaNO3 and KNO3 up to 800 K Thermochimica Acta 60
1983 265-275
[52] Y Takahashi Latent heat measurement by DSC with sapphire as standard material
Thermochim Acta 88(1) 1985 199-204
101
[53] GW Hohne W Hemminger and HJ Flammersheim Differential Scanning Calorimetry
Springer-Verlag Berlin 1996
[54] W Hemminger and G Hohne Calorimetry Fundamentals and Practice Verlag Weinheim
1984
[55] M Merzlyakov and C Schick Thermal conductivity from dynamic response of DSC
Thermochimica Acta 377 2001 183-191
[56] T Kousksou A Jamil S Gibout and Y Zeraouli Thermal analysis of phase change
emulsion Journal of Thermal Analysis and Calorimetry 96 2009 841-852
[57] A Jamil T Kousksou K El Omari Y Zeraouli and Y Le Guer Heat transfer in salt
solutions enclosed in DSC cells Thermochimica Acta 507-508 2010 15-20
[58] MJ Richardson Quantitative aspects of differential scanning calorimetry Thermochimica
Acta 300 1997 15-28
[59] S Rudtsch Uncertainty of heat capacity measurements with differential scanning
calorimeters Thermochimica Acta 382 2002 17-25
[60] M J Maeso and J Largo The phase diagram of LiNO3-NaNO3 and LiNO3-KNO3 the
behavior of liquid mixtures Thermochimica Acta 223 (1993) 145-156
[61] O J Kleppa A new twin high-temperature reaction calorimeter The heats of mixing in
liquid sodium-potassium nitrates Journal of Physical Chemistry 64(12) (1960) 1937-1940
[62] G W H Hhne H K Cammenga W Eysel E Gmelin and W Hemminger The
Temperature Calibration of Scanning Calorimeters Thermochimica Acta 160 1990 1-12
[63] L B Pankratz Thermodynamic Properties of Carbides Nitrides and Other Selected
Substances U S Bureau of Mines Bulletin 696 1994
[64] M Zhang and R G Reddy Thermodynamic properties of C4mim[Tf2N] ionic liquids 0 2
2010 71-76
102
[65] D Mantha T Wang and R G Reddy Thermodynamic Modeling of Eutectic Point in the
LiNO3-NaNO3-KNO3 Ternary System Journal of Phase Equilibria and Diffusion 2011
(accepted)
[66] R G Reddy T Wang and D Mantha Determination of thermodynamic properties of
2KNO3Mg(NO3)2 Thermochimica Acta 2011 (submitted)
[67] T Wang D Mantha and R G Reddy Thermal stability of new LiNO3-NaNO3-KNO3
ternary salt for thermal energy storage system (in preparation)
[68] G D Carvalho E Frollini and W N D Santos Thermal conductivity of polymers by hot-
wire method J Appl Poly Sci 62 (1996) 2281-2285
[69] H Bloom A Doroszkowski and S B Tricklebank Molten salt mixtures IX The thermal
conductivities of molten nitrate systems Aus J Chem 18(8) (1965) 1171-1176
[70] A G Turnbull Thermal conductivity of molten salts Aus J Appl Sci 12 (1961) 30-41
[71] L R White and H T Davis Thermal conductivity of molten alkali nitrates J Chem Phys
47(1967) 5433-5439
[72] M V Peralta-Martinez M J Assael M J Dix L Karagiannidis and W A Wakeham A
Novel Instrument for the Measurement of the Thermal Conductivity of Molten Metal Part1
Instrument‟s Description Int J Thermophysics 27 (2006) 353-375
[73] Y Tada M Harada M Tanlgakl and W Eguchl Laser Flash Method for Measuring
Thermal Conductivity of Liquids Application to Molten Salts Industrial and Engineering
Chemistry Fundamentals 20 1981 333- 336
[74] M V Smirnov V A Khokhlov and E S Filatov Thermal conductivity of molten alkali
halides and their mixtures Electrochimica Acta 32 (1986) 1019-1026
[75] E Marti E Kaisersberger and W D Emmerich NEW ASPECTS OF THERMAL
ANALYSIS Part I Resolution of DSC and means for its optimization Journal of Thermal
Analysis and Calorimetry 77 2004 905-934
103
[76] E Marti E Kaisersberger G Kaiser and WY Ma Netzsch Annual 2000
bdquoThermoanalytical Characterization of Pharmaceuticals‟ Netzsch-Geraumltebau GmbH D-95100
SelbBavaria
[77] P J van Ekeren C M Holl and A J Witteveen A comparative test of differential
scanning calorimeters Journal of Thermal Analysis and Calorimetry 49 1997 1105-1114
[78] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation
Equations for Critically Evaluated Density Surface Tension Electrical Conductance and
Viscosity Data Journal of Physical and Chemical Reference Data 17 1988 1
[79] G F Petersen W A Ewing and G P Smith ldquoDensities of Some Salt Mixturesrdquo Journal of
Chemical and Engineering Data 6 1961 540
[80] P M Nasch and S G Steinemann Density and Thermal Expansion of Molten Manganese
Iron Nickel Copper Aluminum and Tin by Means of the Gamma-Ray Attenuation Technique
Physics and Chemistry of Liquids 29 1995 43-58
[81] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical and Engineering Data 6 1961 493-496
[82] D A Nissen Thermophysical Properties of the Equimolar Mixture NaNO3-KNO3 from
300degC to 600degC Journal of Chemical and Engineering Data 27 1982 269-273
[83] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate
Mixtures Journal of Chemical and Engineering Data 8 1963 469
104
APPENDIX
Appendix A
Table A1 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in solid state
(29815-40315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 342 1290 417 -025
299 027 008 000 343 1317 426 -026
300 059 018 000 344 1345 436 -027
301 091 028 000 345 1372 445 -028
302 123 037 000 346 1399 455 -029
303 154 047 000 347 1427 464 -031
304 186 056 000 348 1454 474 -032
305 217 066 000 349 1481 483 -033
306 248 076 000 350 1508 493 -035
307 279 085 000 351 1535 503 -036
308 310 095 -001 352 1562 512 -038
309 340 104 -001 353 1589 522 -039
310 371 114 -001 354 1616 532 -041
311 401 123 -001 355 1643 541 -042
312 432 133 -002 356 1670 551 -044
313 462 142 -002 357 1697 561 -045
314 492 152 -002 358 1724 570 -047
315 521 161 -003 359 1751 580 -048
316 551 171 -003 360 1777 590 -050
317 581 180 -004 361 1804 600 -052
318 610 190 -004 362 1831 610 -053
319 640 199 -005 363 1858 619 -055
320 669 209 -005 364 1885 629 -057
105
321 698 218 -006 365 1911 639 -059
322 727 228 -007 366 1938 649 -060
323 756 237 -007 367 1965 659 -062
324 785 246 -008 368 1992 669 -064
325 814 256 -009 369 2018 679 -066
326 842 265 -009 370 2045 689 -068
327 871 275 -010 371 2072 699 -070
328 899 284 -011 372 2098 709 -072
329 928 294 -012 373 2125 719 -074
330 956 303 -012 374 2152 729 -076
331 984 313 -013 375 2179 739 -078
332 1012 322 -014 376 2205 750 -080
333 1041 331 -015 377 2232 760 -082
334 1069 341 -016 378 2259 770 -084
335 1096 350 -017 379 2286 780 -086
336 1124 360 -018 380 2312 791 -088
337 1152 369 -019 381 2339 801 -090
338 1180 379 -020 382 2366 811 -093
339 1207 388 -021 383 2393 822 -095
340 1235 398 -022 384 2420 832 -097
341 1263 407 -023 38415 2424 834 -097
Table A2 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in liquid state
(40315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
40315 4287 1565 -163 514 7070 2838 -796
404 4310 1575 -167 515 7094 2850 -803
405 4337 1585 -171 516 7117 2863 -810
406 4363 1596 -175 517 7141 2875 -817
407 4390 1607 -180 518 7165 2887 -824
408 4417 1618 -184 519 7188 2899 -831
409 4443 1629 -189 520 7212 2911 -839
410 4470 1640 -193 521 7235 2924 -846
411 4496 1651 -197 522 7259 2936 -853
412 4523 1662 -202 523 7282 2948 -860
106
413 4549 1672 -206 524 7306 2960 -868
414 4576 1683 -211 525 7329 2973 -875
415 4602 1694 -216 526 7352 2985 -882
416 4629 1705 -220 527 7376 2997 -890
417 4655 1716 -225 528 7399 3010 -897
418 4681 1727 -230 529 7422 3022 -904
419 4708 1738 -234 530 7446 3034 -912
420 4734 1749 -239 531 7469 3047 -919
421 4760 1760 -244 532 7492 3059 -927
422 4786 1771 -249 533 7516 3071 -934
423 4813 1782 -253 534 7539 3084 -942
424 4839 1793 -258 535 7562 3096 -949
425 4865 1804 -263 536 7585 3109 -957
426 4891 1816 -268 537 7608 3121 -965
427 4917 1827 -273 538 7632 3134 -972
428 4943 1838 -278 539 7655 3146 -980
429 4969 1849 -283 540 7678 3158 -988
430 4995 1860 -288 541 7701 3171 -995
431 5021 1871 -293 542 7724 3183 -1003
432 5046 1882 -298 543 7747 3196 -1011
433 5072 1894 -303 544 7770 3208 -1018
434 5098 1905 -308 545 7793 3221 -1026
435 5124 1916 -313 546 7816 3233 -1034
436 5149 1927 -318 547 7839 3246 -1042
437 5175 1938 -323 548 7862 3259 -1050
438 5201 1950 -328 549 7885 3271 -1058
439 5226 1961 -334 550 7908 3284 -1066
440 5252 1972 -339 551 7931 3296 -1073
441 5278 1983 -344 552 7953 3309 -1081
442 5303 1995 -349 553 7976 3322 -1089
443 5329 2006 -355 554 7999 3334 -1097
444 5354 2017 -360 555 8022 3347 -1105
445 5380 2028 -365 556 8045 3359 -1113
446 5405 2040 -371 557 8067 3372 -1121
447 5430 2051 -376 558 8090 3385 -1130
448 5456 2062 -382 559 8113 3398 -1138
449 5481 2074 -387 560 8136 3410 -1146
450 5506 2085 -393 561 8158 3423 -1154
451 5532 2097 -398 562 8181 3436 -1162
452 5557 2108 -404 563 8204 3448 -1170
107
453 5582 2119 -409 564 8226 3461 -1178
454 5607 2131 -415 565 8249 3474 -1187
455 5633 2142 -421 566 8271 3487 -1195
456 5658 2154 -426 567 8294 3499 -1203
457 5683 2165 -432 568 8317 3512 -1212
458 5708 2177 -438 569 8339 3525 -1220
459 5733 2188 -443 570 8362 3538 -1228
460 5758 2200 -449 571 8384 3551 -1237
461 5783 2211 -455 572 8407 3564 -1245
462 5808 2223 -461 573 8429 3576 -1253
463 5833 2234 -466 574 8452 3589 -1262
464 5858 2246 -472 575 8474 3602 -1270
465 5883 2257 -478 576 8496 3615 -1279
466 5907 2269 -484 577 8519 3628 -1287
467 5932 2280 -490 578 8541 3641 -1296
468 5957 2292 -496 579 8564 3654 -1304
469 5982 2304 -502 580 8586 3667 -1313
470 6007 2315 -508 581 8608 3680 -1322
471 6031 2327 -514 582 8631 3693 -1330
472 6056 2339 -520 583 8653 3706 -1339
473 6081 2350 -526 584 8675 3719 -1348
474 6105 2362 -532 585 8697 3732 -1356
475 6130 2373 -538 586 8720 3745 -1365
476 6155 2385 -544 587 8742 3758 -1374
477 6179 2397 -551 588 8764 3771 -1382
478 6204 2409 -557 589 8786 3784 -1391
479 6228 2420 -563 590 8808 3797 -1400
480 6253 2432 -569 591 8831 3810 -1409
481 6277 2444 -575 592 8853 3823 -1418
482 6301 2456 -582 593 8875 3836 -1426
483 6326 2467 -588 594 8897 3849 -1435
484 6350 2479 -594 595 8919 3863 -1444
485 6375 2491 -601 596 8941 3876 -1453
486 6399 2503 -607 597 8963 3889 -1462
487 6423 2515 -614 598 8985 3902 -1471
488 6448 2526 -620 599 9007 3915 -1480
489 6472 2538 -626 600 9029 3928 -1489
490 6496 2550 -633 601 9051 3942 -1498
491 6520 2562 -639 602 9073 3955 -1507
492 6544 2574 -646 603 9095 3968 -1516
108
493 6569 2586 -653 604 9117 3981 -1525
494 6593 2598 -659 605 9139 3994 -1535
495 6617 2610 -666 606 9161 4008 -1544
496 6641 2621 -672 607 9183 4021 -1553
497 6665 2633 -679 608 9205 4034 -1562
498 6689 2645 -686 609 9226 4048 -1571
499 6713 2657 -692 610 9248 4061 -1581
500 6737 2669 -699 611 9270 4074 -1590
501 6761 2681 -706 612 9292 4088 -1599
502 6785 2693 -713 613 9314 4101 -1608
503 6809 2705 -719 614 9335 4114 -1618
504 6833 2717 -726 615 9357 4128 -1627
505 6856 2729 -733 616 9379 4141 -1636
506 6880 2741 -740 617 9401 4154 -1646
507 6904 2754 -747 618 9422 4168 -1655
508 6928 2766 -754 619 9444 4181 -1665
509 6952 2778 -761 620 9466 4195 -1674
510 6975 2790 -768 621 9487 4208 -1684
511 6999 2802 -775 622 9509 4222 -1693
512 7023 2814 -782 623 9531 4235 -1703
513 7047 2826 -789 62315 9534 4237 -1704
109
Appendix B
Table B1 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(29815-39215K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 347 1233 382 -046
299 022 006 000 348 1258 390 -048
300 049 014 -001 349 1283 398 -049
301 075 022 -001 350 1307 406 -051
302 101 029 -001 351 1332 415 -053
303 127 037 -002 352 1356 423 -054
304 153 044 -002 353 1381 431 -056
305 179 052 -003 354 1405 440 -058
306 205 059 -003 355 1430 448 -060
307 230 067 -004 356 1455 456 -061
308 256 075 -004 357 1479 465 -063
309 282 082 -005 358 1504 473 -065
310 308 090 -005 359 1528 482 -067
311 333 098 -006 360 1553 490 -069
312 359 105 -007 361 1577 498 -071
313 384 113 -007 362 1602 507 -073
314 410 121 -008 363 1626 515 -075
315 435 128 -009 364 1651 524 -077
316 461 136 -010 365 1675 533 -079
317 486 144 -010 366 1700 541 -081
318 511 151 -011 367 1724 550 -083
319 537 159 -012 368 1749 558 -085
320 562 167 -013 369 1773 567 -087
321 587 175 -014 370 1798 576 -089
322 612 182 -015 371 1822 584 -092
323 637 190 -016 372 1847 593 -094
324 663 198 -017 373 1871 602 -096
325 688 206 -018 374 1896 611 -098
326 713 214 -019 375 1920 620 -100
327 738 222 -020 376 1945 628 -103
328 763 229 -021 377 1969 637 -105
329 788 237 -022 378 1994 646 -107
110
330 813 245 -023 379 2018 655 -110
331 838 253 -024 380 2043 664 -112
332 863 261 -025 381 2068 673 -115
333 887 269 -027 382 2092 682 -117
334 912 277 -028 383 2117 691 -120
335 937 285 -029 384 2141 700 -122
336 962 293 -030 385 2166 709 -125
337 987 301 -032 386 2191 718 -127
338 1011 309 -033 387 2215 727 -130
339 1036 317 -034 388 2240 737 -132
340 1061 325 -036 389 2265 746 -135
341 1086 333 -037 390 2289 755 -138
342 1110 341 -039 391 2314 764 -140
343 1135 349 -040 392 2339 774 -143
344 1160 357 -042 39215 2342 775 -144
345 1184 365 -043
Table B2 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(41315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
414 3280 1149 -209 520 5608 2235 -682
415 3302 1158 -212 521 5630 2246 -687
416 3325 1167 -216 522 5651 2257 -693
417 3348 1177 -219 523 5672 2268 -698
418 3370 1186 -223 524 5694 2279 -704
419 3393 1196 -226 525 5715 2290 -710
420 3416 1205 -229 526 5736 2302 -716
421 3438 1215 -233 527 5757 2313 -721
422 3461 1224 -236 528 5779 2324 -727
423 3483 1234 -240 529 5800 2335 -733
424 3506 1243 -243 530 5821 2347 -739
425 3529 1253 -247 531 5842 2358 -745
426 3551 1263 -250 532 5864 2369 -750
427 3574 1272 -254 533 5885 2380 -756
428 3596 1282 -257 534 5906 2392 -762
429 3619 1291 -261 535 5927 2403 -768
111
430 3641 1301 -265 536 5948 2414 -774
431 3663 1311 -268 537 5970 2426 -780
432 3686 1320 -272 538 5991 2437 -786
433 3708 1330 -276 539 6012 2449 -792
434 3731 1340 -279 540 6033 2460 -798
435 3753 1350 -283 541 6054 2471 -804
436 3775 1359 -287 542 6075 2483 -810
437 3798 1369 -291 543 6096 2494 -816
438 3820 1379 -294 544 6118 2506 -822
439 3842 1389 -298 545 6139 2517 -828
440 3865 1398 -302 546 6160 2529 -835
441 3887 1408 -306 547 6181 2540 -841
442 3909 1418 -310 548 6202 2552 -847
443 3932 1428 -314 549 6223 2563 -853
444 3954 1438 -318 550 6244 2575 -859
445 3976 1448 -322 551 6265 2586 -866
446 3998 1458 -326 552 6286 2598 -872
447 4021 1468 -330 553 6307 2610 -878
448 4043 1477 -334 554 6328 2621 -884
449 4065 1487 -338 555 6349 2633 -891
450 4087 1497 -342 556 6370 2645 -897
451 4109 1507 -346 557 6391 2656 -904
452 4131 1517 -350 558 6412 2668 -910
453 4154 1527 -354 559 6433 2680 -916
454 4176 1537 -358 560 6454 2691 -923
455 4198 1547 -363 561 6475 2703 -929
456 4220 1557 -367 562 6496 2715 -936
457 4242 1568 -371 563 6517 2727 -942
458 4264 1578 -375 564 6538 2738 -949
459 4286 1588 -380 565 6559 2750 -955
460 4308 1598 -384 566 6580 2762 -962
461 4330 1608 -388 567 6600 2774 -969
462 4352 1618 -393 568 6621 2786 -975
463 4374 1628 -397 569 6642 2798 -982
464 4396 1639 -401 570 6663 2810 -988
465 4418 1649 -406 571 6684 2821 -995
466 4440 1659 -410 572 6705 2833 -1002
467 4462 1669 -415 573 6726 2845 -1009
468 4484 1680 -419 574 6747 2857 -1015
469 4506 1690 -424 575 6767 2869 -1022
112
470 4528 1700 -428 576 6788 2881 -1029
471 4550 1710 -433 577 6809 2893 -1036
472 4572 1721 -437 578 6830 2905 -1042
473 4593 1731 -442 579 6851 2917 -1049
474 4615 1741 -446 580 6871 2929 -1056
475 4637 1752 -451 581 6892 2941 -1063
476 4659 1762 -456 582 6913 2953 -1070
477 4681 1773 -460 583 6934 2966 -1077
478 4703 1783 -465 584 6954 2978 -1084
479 4724 1793 -470 585 6975 2990 -1091
480 4746 1804 -474 586 6996 3002 -1098
481 4768 1814 -479 587 7017 3014 -1105
482 4790 1825 -484 588 7037 3026 -1112
483 4812 1835 -489 589 7058 3038 -1119
484 4833 1846 -494 590 7079 3051 -1126
485 4855 1856 -498 591 7100 3063 -1133
486 4877 1867 -503 592 7120 3075 -1140
487 4898 1877 -508 593 7141 3087 -1147
488 4920 1888 -513 594 7162 3100 -1154
489 4942 1899 -518 595 7182 3112 -1162
490 4963 1909 -523 596 7203 3124 -1169
491 4985 1920 -528 597 7224 3137 -1176
492 5007 1930 -533 598 7244 3149 -1183
493 5028 1941 -538 599 7265 3161 -1190
494 5050 1952 -543 600 7285 3174 -1198
495 5072 1962 -548 601 7306 3186 -1205
496 5093 1973 -553 602 7327 3198 -1212
497 5115 1984 -558 603 7347 3211 -1220
498 5136 1995 -563 604 7368 3223 -1227
499 5158 2005 -568 605 7389 3236 -1234
500 5180 2016 -574 606 7409 3248 -1242
501 5201 2027 -579 607 7430 3261 -1249
502 5223 2038 -584 608 7450 3273 -1257
503 5244 2049 -589 609 7471 3286 -1264
504 5266 2059 -595 610 7491 3298 -1272
505 5287 2070 -600 611 7512 3311 -1279
506 5309 2081 -605 612 7532 3323 -1287
507 5330 2092 -610 613 7553 3336 -1294
508 5352 2103 -616 614 7573 3348 -1302
509 5373 2114 -621 615 7594 3361 -1309
113
510 5394 2125 -627 616 7615 3374 -1317
511 5416 2136 -632 617 7635 3386 -1325
512 5437 2147 -637 618 7656 3399 -1332
513 5459 2158 -643 619 7676 3412 -1340
514 5480 2169 -648 620 7696 3424 -1348
515 5502 2180 -654 621 7717 3437 -1355
516 5523 2191 -659 622 7737 3450 -1363
517 5544 2202 -665 623 7758 3462 -1371
518 5566 2213 -670 62315 7761 3464 -1372
114
Appendix C
Table C1 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in solid
state (29815-36415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 333 1937 611 -034
299 048 014 000 334 1992 629 -036
300 104 031 000 335 2047 647 -038
301 160 048 000 336 2102 666 -040
302 216 065 000 337 2156 684 -042
303 272 082 -001 338 2211 703 -045
304 329 099 -001 339 2266 721 -047
305 385 116 -001 340 2321 740 -049
306 441 133 -002 341 2375 758 -052
307 496 150 -002 342 2430 777 -054
308 552 167 -003 343 2485 796 -056
309 608 185 -003 344 2539 815 -059
310 664 202 -004 345 2594 833 -062
311 720 219 -005 346 2648 852 -064
312 776 236 -006 347 2703 871 -067
313 831 254 -006 348 2757 890 -070
314 887 271 -007 349 2812 909 -072
315 942 289 -008 350 2866 928 -075
316 998 306 -009 351 2921 947 -078
317 1054 324 -010 352 2975 966 -081
318 1109 341 -011 353 3029 985 -084
319 1164 359 -012 354 3084 1004 -087
320 1220 377 -014 355 3138 1024 -090
321 1275 395 -015 356 3192 1043 -094
322 1331 412 -016 357 3246 1062 -097
323 1386 430 -018 358 3300 1082 -100
324 1441 448 -019 359 3355 1101 -103
325 1496 466 -020 360 3409 1120 -107
326 1552 484 -022 361 3463 1140 -110
327 1607 502 -024 362 3517 1159 -114
328 1662 520 -025 363 3571 1179 -117
329 1717 538 -027 364 3625 1199 -121
115
330 1772 556 -029 36415 3633 1202 -121
331 1827 574 -030
332 1882 593 -032
Table C2 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in liquid
state (42115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
42115 7428 2673 -455 523 11788 4725 -1440
422 7468 2690 -461 524 11827 4745 -1452
423 7515 2710 -468 525 11866 4766 -1464
424 7562 2730 -476 526 11904 4786 -1476
425 7608 2750 -484 527 11943 4807 -1488
426 7655 2770 -491 528 11982 4827 -1500
427 7702 2790 -499 529 12021 4847 -1512
428 7748 2810 -507 530 12059 4868 -1524
429 7795 2830 -514 531 12098 4888 -1536
430 7841 2849 -522 532 12137 4909 -1548
431 7887 2869 -530 533 12175 4929 -1560
432 7933 2889 -538 534 12213 4950 -1572
433 7979 2909 -546 535 12252 4970 -1584
434 8025 2929 -554 536 12290 4991 -1597
435 8071 2949 -562 537 12328 5011 -1609
436 8117 2969 -570 538 12366 5032 -1621
437 8163 2989 -578 539 12404 5052 -1634
438 8208 3009 -586 540 12442 5073 -1646
439 8254 3029 -595 541 12480 5093 -1659
440 8299 3049 -603 542 12518 5114 -1671
441 8345 3069 -611 543 12556 5134 -1684
442 8390 3089 -620 544 12594 5155 -1696
443 8435 3109 -628 545 12632 5175 -1709
444 8480 3129 -636 546 12669 5196 -1721
445 8525 3149 -645 547 12707 5217 -1734
446 8570 3169 -654 548 12745 5237 -1747
116
447 8615 3189 -662 549 12782 5258 -1760
448 8659 3209 -671 550 12820 5278 -1772
449 8704 3229 -679 551 12857 5299 -1785
450 8748 3249 -688 552 12894 5319 -1798
451 8793 3269 -697 553 12932 5340 -1811
452 8837 3289 -706 554 12969 5361 -1824
453 8881 3309 -715 555 13006 5381 -1837
454 8926 3329 -724 556 13043 5402 -1850
455 8970 3349 -732 557 13080 5422 -1863
456 9014 3369 -741 558 13117 5443 -1876
457 9058 3389 -750 559 13154 5464 -1889
458 9102 3409 -760 560 13191 5484 -1902
459 9145 3429 -769 561 13228 5505 -1916
460 9189 3449 -778 562 13264 5526 -1929
461 9233 3469 -787 563 13301 5546 -1942
462 9276 3489 -796 564 13338 5567 -1956
463 9319 3509 -806 565 13374 5588 -1969
464 9363 3529 -815 566 13411 5608 -1982
465 9406 3549 -824 567 13447 5629 -1996
466 9449 3570 -834 568 13484 5650 -2009
467 9492 3590 -843 569 13520 5670 -2023
468 9535 3610 -853 570 13557 5691 -2036
469 9578 3630 -862 571 13593 5712 -2050
470 9621 3650 -872 572 13629 5732 -2063
471 9664 3670 -882 573 13665 5753 -2077
472 9707 3690 -891 574 13701 5774 -2091
473 9749 3710 -901 575 13737 5795 -2104
474 9792 3731 -911 576 13773 5815 -2118
475 9834 3751 -921 577 13809 5836 -2132
476 9877 3771 -930 578 13845 5857 -2146
477 9919 3791 -940 579 13881 5877 -2160
478 9961 3811 -950 580 13917 5898 -2174
479 10004 3831 -960 581 13953 5919 -2188
480 10046 3852 -970 582 13988 5940 -2202
481 10088 3872 -980 583 14024 5960 -2216
482 10130 3892 -990 584 14060 5981 -2230
483 10171 3912 -1001 585 14095 6002 -2244
484 10213 3932 -1011 586 14131 6023 -2258
485 10255 3953 -1021 587 14166 6044 -2272
486 10297 3973 -1031 588 14201 6064 -2286
117
487 10338 3993 -1042 589 14237 6085 -2300
488 10380 4013 -1052 590 14272 6106 -2315
489 10421 4034 -1062 591 14307 6127 -2329
490 10462 4054 -1073 592 14342 6148 -2343
491 10504 4074 -1083 593 14378 6168 -2358
492 10545 4094 -1094 594 14413 6189 -2372
493 10586 4114 -1104 595 14448 6210 -2386
494 10627 4135 -1115 596 14483 6231 -2401
495 10668 4155 -1126 597 14518 6252 -2415
496 10709 4175 -1136 598 14552 6273 -2430
497 10750 4196 -1147 599 14587 6293 -2444
498 10791 4216 -1158 600 14622 6314 -2459
499 10831 4236 -1169 601 14657 6335 -2474
500 10872 4256 -1179 602 14692 6356 -2488
501 10912 4277 -1190 603 14726 6377 -2503
502 10953 4297 -1201 604 14761 6398 -2518
503 10993 4317 -1212 605 14795 6419 -2533
504 11034 4338 -1223 606 14830 6439 -2547
505 11074 4358 -1234 607 14864 6460 -2562
506 11114 4378 -1245 608 14899 6481 -2577
507 11154 4399 -1257 609 14933 6502 -2592
508 11194 4419 -1268 610 14967 6523 -2607
509 11234 4439 -1279 611 15002 6544 -2622
510 11274 4460 -1290 612 15036 6565 -2637
511 11314 4480 -1302 613 15070 6586 -2652
512 11354 4500 -1313 614 15104 6607 -2667
513 11394 4521 -1324 615 15138 6628 -2682
514 11433 4541 -1336 616 15172 6649 -2697
515 11473 4562 -1347 617 15206 6670 -2713
516 11513 4582 -1359 618 15240 6691 -2728
517 11552 4602 -1370 619 15274 6712 -2743
518 11591 4623 -1382 620 15308 6733 -2758
519 11631 4643 -1393 621 15342 6754 -2774
520 11670 4664 -1405 622 15375 6774 -2789
521 11709 4684 -1417 623 15409 6795 -2804
522 11748 4704 -1428 62315 15414 6799 -2807
118
Appendix D
Table D1 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in solid state
(29815-36315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
299 021 006 000 333 867 277 -012
300 047 014 000 334 891 285 -012
301 072 022 000 335 916 293 -013
302 097 029 000 336 940 302 -014
303 122 037 000 337 964 310 -015
304 147 045 000 338 989 318 -016
305 172 053 000 339 1013 327 -017
306 197 060 000 340 1037 335 -018
307 223 068 000 341 1061 343 -019
308 248 076 000 342 1085 352 -019
309 273 084 000 343 1109 360 -020
310 298 092 -001 344 1134 369 -021
311 323 099 -001 345 1158 377 -022
312 348 107 -001 346 1182 385 -024
313 373 115 -001 347 1206 394 -025
314 398 123 -002 348 1230 402 -026
315 423 131 -002 349 1254 411 -027
316 447 139 -002 350 1277 419 -028
317 472 147 -003 351 1301 428 -029
318 497 155 -003 352 1325 436 -030
319 522 163 -003 353 1349 445 -032
320 547 171 -004 354 1373 453 -033
321 572 179 -004 355 1396 462 -034
322 596 187 -005 356 1420 470 -035
323 621 195 -005 357 1444 479 -037
324 646 203 -006 358 1467 487 -038
325 670 211 -006 359 1491 496 -039
326 695 220 -007 360 1514 504 -041
327 720 228 -008 361 1538 513 -042
328 744 236 -008 362 1561 522 -043
329 769 244 -009 363 1584 530 -045
330 793 252 -010 36315 1588 532 -045
119
331 818 260 -010
Table D2 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in liquid
state (38115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
38115 2281 765 -104 503 5639 2242 -594
382 2307 775 -106 504 5664 2255 -600
383 2338 787 -109 505 5689 2267 -606
384 2369 798 -111 506 5713 2280 -611
385 2399 810 -113 507 5738 2292 -617
386 2430 822 -116 508 5763 2305 -623
387 2460 834 -118 509 5787 2317 -629
388 2491 846 -121 510 5812 2330 -634
389 2521 857 -123 511 5836 2342 -640
390 2551 869 -126 512 5861 2355 -646
391 2582 881 -128 513 5885 2367 -652
392 2612 893 -131 514 5910 2380 -658
393 2642 905 -134 515 5934 2392 -664
394 2672 917 -136 516 5959 2405 -670
395 2702 928 -139 517 5983 2417 -676
396 2732 940 -142 518 6007 2430 -682
397 2762 952 -144 519 6032 2443 -688
398 2792 964 -147 520 6056 2455 -694
399 2821 976 -150 521 6080 2468 -700
400 2851 988 -153 522 6104 2480 -706
401 2881 999 -156 523 6128 2493 -712
402 2910 1011 -159 524 6152 2506 -718
403 2940 1023 -162 525 6176 2518 -724
404 2969 1035 -164 526 6200 2531 -731
405 2999 1047 -167 527 6224 2544 -737
406 3028 1059 -170 528 6248 2556 -743
407 3057 1071 -174 529 6272 2569 -749
408 3087 1083 -177 530 6296 2581 -756
120
409 3116 1095 -180 531 6320 2594 -762
410 3145 1107 -183 532 6344 2607 -768
411 3174 1119 -186 533 6368 2619 -775
412 3203 1130 -189 534 6391 2632 -781
413 3232 1142 -192 535 6415 2645 -787
414 3261 1154 -196 536 6439 2657 -794
415 3290 1166 -199 537 6462 2670 -800
416 3319 1178 -202 538 6486 2683 -807
417 3347 1190 -206 539 6510 2696 -813
418 3376 1202 -209 540 6533 2708 -820
419 3405 1214 -212 541 6557 2721 -826
420 3433 1226 -216 542 6580 2734 -833
421 3462 1238 -219 543 6604 2746 -839
422 3490 1250 -223 544 6627 2759 -846
423 3519 1262 -226 545 6650 2772 -853
424 3547 1274 -230 546 6674 2785 -859
425 3575 1286 -233 547 6697 2797 -866
426 3604 1298 -237 548 6720 2810 -873
427 3632 1310 -240 549 6744 2823 -879
428 3660 1322 -244 550 6767 2836 -886
429 3688 1334 -248 551 6790 2848 -893
430 3716 1346 -251 552 6813 2861 -900
431 3744 1358 -255 553 6836 2874 -907
432 3772 1371 -259 554 6860 2887 -913
433 3800 1383 -263 555 6883 2900 -920
434 3828 1395 -267 556 6906 2912 -927
435 3856 1407 -270 557 6929 2925 -934
436 3883 1419 -274 558 6952 2938 -941
437 3911 1431 -278 559 6975 2951 -948
438 3939 1443 -282 560 6998 2964 -955
439 3966 1455 -286 561 7020 2976 -962
440 3994 1467 -290 562 7043 2989 -969
441 4021 1479 -294 563 7066 3002 -976
442 4049 1491 -298 564 7089 3015 -983
443 4076 1504 -302 565 7112 3028 -990
444 4103 1516 -306 566 7134 3041 -997
445 4131 1528 -310 567 7157 3054 -1005
446 4158 1540 -314 568 7180 3066 -1012
447 4185 1552 -319 569 7203 3079 -1019
448 4212 1564 -323 570 7225 3092 -1026
121
449 4240 1576 -327 571 7248 3105 -1033
450 4267 1589 -331 572 7270 3118 -1041
451 4294 1601 -336 573 7293 3131 -1048
452 4321 1613 -340 574 7315 3144 -1055
453 4347 1625 -344 575 7338 3157 -1063
454 4374 1637 -349 576 7360 3170 -1070
455 4401 1650 -353 577 7383 3183 -1077
456 4428 1662 -357 578 7405 3196 -1085
457 4455 1674 -362 579 7428 3208 -1092
458 4481 1686 -366 580 7450 3221 -1100
459 4508 1698 -371 581 7472 3234 -1107
460 4535 1711 -375 582 7494 3247 -1114
461 4561 1723 -380 583 7517 3260 -1122
462 4588 1735 -384 584 7539 3273 -1129
463 4614 1747 -389 585 7561 3286 -1137
464 4641 1760 -394 586 7583 3299 -1145
465 4667 1772 -398 587 7605 3312 -1152
466 4693 1784 -403 588 7628 3325 -1160
467 4720 1796 -408 589 7650 3338 -1167
468 4746 1809 -412 590 7672 3351 -1175
469 4772 1821 -417 591 7694 3364 -1183
470 4798 1833 -422 592 7716 3377 -1191
471 4825 1846 -427 593 7738 3390 -1198
472 4851 1858 -432 594 7760 3403 -1206
473 4877 1870 -437 595 7782 3416 -1214
474 4903 1882 -441 596 7804 3429 -1222
475 4929 1895 -446 597 7825 3442 -1229
476 4955 1907 -451 598 7847 3455 -1237
477 4980 1919 -456 599 7869 3469 -1245
478 5006 1932 -461 600 7891 3482 -1253
479 5032 1944 -466 601 7913 3495 -1261
480 5058 1956 -471 602 7934 3508 -1269
481 5083 1969 -476 603 7956 3521 -1277
482 5109 1981 -481 604 7978 3534 -1285
483 5135 1994 -487 605 8000 3547 -1293
484 5160 2006 -492 606 8021 3560 -1301
485 5186 2018 -497 607 8043 3573 -1309
486 5211 2031 -502 608 8064 3586 -1317
487 5237 2043 -507 609 8086 3599 -1325
488 5262 2055 -513 610 8107 3613 -1333
122
489 5288 2068 -518 611 8129 3626 -1341
490 5313 2080 -523 612 8150 3639 -1349
491 5338 2093 -528 613 8172 3652 -1357
492 5364 2105 -534 614 8193 3665 -1366
493 5389 2117 -539 615 8215 3678 -1374
494 5414 2130 -545 616 8236 3692 -1382
495 5439 2142 -550 617 8258 3705 -1390
496 5464 2155 -555 618 8279 3718 -1398
497 5489 2167 -561 619 8300 3731 -1407
498 5514 2180 -566 620 8321 3744 -1415
499 5539 2192 -572 621 8343 3757 -1423
500 5564 2205 -578 622 8364 3771 -1432
501 5589 2217 -583 623 8385 3784 -1441
502 5614 2230 -589 62315 8388 3786 -1443
123
Appendix E
Table E1 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in solid state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 913 287 -014
299 025 007 000 331 941 296 -015
300 054 016 000 332 970 306 -016
301 083 025 000 333 998 315 -017
302 112 034 000 334 1026 324 -018
303 141 042 000 335 1054 334 -019
304 170 051 000 336 1081 343 -020
305 199 060 -001 337 1109 353 -021
306 228 069 -001 338 1137 362 -022
307 257 078 -001 339 1165 371 -024
308 286 087 -001 340 1193 381 -025
309 315 096 -002 341 1221 390 -026
310 343 105 -002 342 1248 400 -027
311 372 113 -002 343 1276 409 -028
312 401 122 -003 344 1304 419 -030
313 430 131 -003 345 1331 428 -031
314 458 140 -003 346 1359 438 -032
315 487 149 -004 347 1386 447 -034
316 516 159 -004 348 1414 457 -035
317 544 168 -005 349 1441 466 -036
318 573 177 -006 350 1468 476 -038
319 602 186 -006 351 1496 486 -039
320 630 195 -007 352 1523 495 -041
321 659 204 -007 353 1550 505 -042
322 687 213 -008 354 1577 514 -044
323 715 222 -009 355 1605 524 -046
324 744 232 -009 356 1632 534 -047
325 772 241 -010 357 1659 543 -049
326 800 250 -011 358 1686 553 -050
327 829 259 -012 359 1713 563 -052
328 857 269 -013 35915 1717 564 -052
329 885 278 -013
124
Table E2 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in liquid state (376-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2323 777 -094 500 5525 2173 -590
376 2347 786 -096 501 5548 2184 -595
377 2375 797 -098 502 5572 2196 -601
378 2403 808 -101 503 5595 2208 -606
379 2431 818 -103 504 5619 2220 -612
380 2459 829 -106 505 5642 2232 -618
381 2487 839 -108 506 5665 2243 -623
382 2515 850 -111 507 5689 2255 -629
383 2542 861 -113 508 5712 2267 -635
384 2570 871 -116 509 5735 2279 -640
385 2598 882 -118 510 5759 2291 -646
386 2626 893 -121 511 5782 2303 -652
387 2653 903 -123 512 5805 2315 -658
388 2681 914 -126 513 5828 2326 -664
389 2708 925 -129 514 5852 2338 -669
390 2736 935 -132 515 5875 2350 -675
391 2763 946 -134 516 5898 2362 -681
392 2791 957 -137 517 5921 2374 -687
393 2818 968 -140 518 5944 2386 -693
394 2845 978 -143 519 5967 2398 -699
395 2873 989 -146 520 5990 2410 -705
396 2900 1000 -148 521 6013 2422 -711
397 2927 1011 -151 522 6036 2434 -717
398 2954 1022 -154 523 6059 2446 -723
399 2981 1032 -157 524 6082 2458 -729
400 3008 1043 -160 525 6105 2470 -735
401 3035 1054 -163 526 6128 2482 -741
402 3062 1065 -166 527 6151 2494 -747
403 3089 1076 -169 528 6173 2506 -754
404 3116 1086 -172 529 6196 2518 -760
405 3143 1097 -176 530 6219 2530 -766
125
406 3170 1108 -179 531 6242 2542 -772
407 3197 1119 -182 532 6265 2554 -778
408 3223 1130 -185 533 6287 2566 -785
409 3250 1141 -188 534 6310 2578 -791
410 3277 1152 -192 535 6333 2591 -797
411 3303 1163 -195 536 6355 2603 -804
412 3330 1174 -198 537 6378 2615 -810
413 3356 1185 -202 538 6400 2627 -816
414 3383 1195 -205 539 6423 2639 -823
415 3409 1206 -208 540 6445 2651 -829
416 3436 1217 -212 541 6468 2663 -836
417 3462 1228 -215 542 6490 2676 -842
418 3488 1239 -219 543 6513 2688 -849
419 3515 1250 -222 544 6535 2700 -855
420 3541 1261 -226 545 6558 2712 -862
421 3567 1272 -229 546 6580 2724 -868
422 3593 1283 -233 547 6602 2737 -875
423 3619 1294 -236 548 6625 2749 -882
424 3645 1305 -240 549 6647 2761 -888
425 3671 1317 -244 550 6669 2773 -895
426 3697 1328 -247 551 6692 2786 -902
427 3723 1339 -251 552 6714 2798 -908
428 3749 1350 -255 553 6736 2810 -915
429 3775 1361 -259 554 6758 2822 -922
430 3801 1372 -262 555 6780 2835 -929
431 3827 1383 -266 556 6803 2847 -935
432 3852 1394 -270 557 6825 2859 -942
433 3878 1405 -274 558 6847 2872 -949
434 3904 1416 -278 559 6869 2884 -956
435 3929 1428 -282 560 6891 2896 -963
436 3955 1439 -286 561 6913 2909 -970
437 3981 1450 -290 562 6935 2921 -977
438 4006 1461 -294 563 6957 2933 -983
439 4032 1472 -298 564 6979 2946 -990
440 4057 1483 -302 565 7001 2958 -997
441 4083 1495 -306 566 7023 2971 -1004
442 4108 1506 -310 567 7045 2983 -1011
443 4133 1517 -314 568 7067 2995 -1019
444 4159 1528 -318 569 7089 3008 -1026
445 4184 1540 -322 570 7110 3020 -1033
126
446 4209 1551 -327 571 7132 3033 -1040
447 4234 1562 -331 572 7154 3045 -1047
448 4260 1573 -335 573 7176 3058 -1054
449 4285 1585 -339 574 7198 3070 -1061
450 4310 1596 -344 575 7219 3083 -1069
451 4335 1607 -348 576 7241 3095 -1076
452 4360 1618 -352 577 7263 3108 -1083
453 4385 1630 -357 578 7284 3120 -1090
454 4410 1641 -361 579 7306 3133 -1098
455 4435 1652 -365 580 7328 3145 -1105
456 4460 1664 -370 581 7349 3158 -1112
457 4485 1675 -374 582 7371 3170 -1120
458 4510 1687 -379 583 7393 3183 -1127
459 4534 1698 -383 584 7414 3195 -1134
460 4559 1709 -388 585 7436 3208 -1142
461 4584 1721 -393 586 7457 3221 -1149
462 4609 1732 -397 587 7479 3233 -1157
463 4633 1743 -402 588 7500 3246 -1164
464 4658 1755 -406 589 7522 3258 -1172
465 4683 1766 -411 590 7543 3271 -1179
466 4707 1778 -416 591 7564 3284 -1187
467 4732 1789 -420 592 7586 3296 -1194
468 4756 1801 -425 593 7607 3309 -1202
469 4781 1812 -430 594 7628 3322 -1210
470 4805 1824 -435 595 7650 3334 -1217
471 4830 1835 -440 596 7671 3347 -1225
472 4854 1847 -444 597 7692 3360 -1233
473 4878 1858 -449 598 7714 3373 -1240
474 4903 1870 -454 599 7735 3385 -1248
475 4927 1881 -459 600 7756 3398 -1256
476 4951 1893 -464 601 7777 3411 -1264
477 4975 1904 -469 602 7799 3423 -1271
478 5000 1916 -474 603 7820 3436 -1279
479 5024 1927 -479 604 7841 3449 -1287
480 5048 1939 -484 605 7862 3462 -1295
481 5072 1951 -489 606 7883 3475 -1303
482 5096 1962 -494 607 7904 3487 -1311
483 5120 1974 -499 608 7925 3500 -1318
484 5144 1985 -504 609 7946 3513 -1326
485 5168 1997 -510 610 7967 3526 -1334
127
486 5192 2009 -515 611 7988 3539 -1342
487 5216 2020 -520 612 8009 3551 -1350
488 5240 2032 -525 613 8030 3564 -1358
489 5264 2044 -530 614 8051 3577 -1366
490 5288 2055 -536 615 8072 3590 -1374
491 5312 2067 -541 616 8093 3603 -1383
492 5335 2079 -546 617 8114 3616 -1391
493 5359 2090 -552 618 8135 3629 -1399
494 5383 2102 -557 619 8156 3642 -1407
495 5407 2114 -562 620 8177 3655 -1415
496 5430 2126 -568 621 8198 3667 -1423
497 5454 2137 -573 622 8219 3680 -1431
498 5478 2149 -579 623 8239 3693 -1440
499 5501 2161 -584 62315 8242 3695 -1441
128
Appendix F
Table F1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in solid
state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 1063 334 -017
299 029 009 000 331 1096 345 -018
300 063 019 000 332 1128 356 -019
301 097 029 000 333 1161 366 -020
302 131 039 000 334 1193 377 -021
303 165 050 000 335 1225 388 -022
304 199 060 -001 336 1258 399 -024
305 233 070 -001 337 1290 410 -025
306 267 081 -001 338 1322 421 -026
307 300 091 -001 339 1355 432 -028
308 334 101 -002 340 1387 443 -029
309 368 112 -002 341 1419 454 -030
310 401 122 -002 342 1451 464 -032
311 435 133 -003 343 1483 475 -033
312 468 143 -003 344 1515 486 -035
313 502 153 -004 345 1547 497 -036
314 535 164 -004 346 1578 508 -038
315 569 174 -005 347 1610 519 -039
316 602 185 -005 348 1642 531 -041
317 635 196 -006 349 1674 542 -043
318 668 206 -006 350 1705 553 -044
319 702 217 -007 351 1737 564 -046
320 735 227 -008 352 1769 575 -048
321 768 238 -009 353 1800 586 -049
322 801 248 -009 354 1832 597 -051
323 834 259 -010 355 1863 608 -053
324 867 270 -011 356 1894 619 -055
325 900 280 -012 357 1926 631 -057
326 932 291 -013 358 1957 642 -059
327 965 302 -014 359 1988 653 -061
328 998 313 -015 35915 1993 655 -061
329 1030 323 -016
129
Table F2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in liquid
state (37515-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2691 926 -083 500 6111 2416 -640
376 2717 936 -085 501 6136 2428 -646
377 2747 948 -088 502 6161 2440 -652
378 2778 959 -091 503 6185 2453 -658
379 2808 971 -094 504 6210 2465 -665
380 2838 982 -096 505 6235 2478 -671
381 2869 994 -099 506 6259 2490 -677
382 2899 1005 -102 507 6284 2502 -683
383 2929 1017 -105 508 6308 2515 -690
384 2959 1028 -108 509 6333 2527 -696
385 2989 1040 -111 510 6357 2540 -702
386 3019 1051 -114 511 6381 2552 -709
387 3049 1063 -117 512 6406 2565 -715
388 3079 1075 -120 513 6430 2577 -721
389 3109 1086 -123 514 6454 2590 -728
390 3138 1098 -126 515 6479 2602 -734
391 3168 1109 -129 516 6503 2615 -741
392 3198 1121 -133 517 6527 2627 -747
393 3227 1132 -136 518 6551 2640 -754
394 3257 1144 -139 519 6575 2652 -760
395 3286 1156 -142 520 6599 2665 -767
396 3316 1167 -146 521 6624 2677 -774
397 3345 1179 -149 522 6648 2690 -780
398 3374 1191 -152 523 6672 2702 -787
399 3403 1202 -156 524 6696 2715 -794
400 3433 1214 -159 525 6719 2727 -800
401 3462 1226 -163 526 6743 2740 -807
402 3491 1237 -166 527 6767 2753 -814
403 3520 1249 -170 528 6791 2765 -821
404 3549 1261 -173 529 6815 2778 -827
405 3578 1272 -177 530 6839 2790 -834
130
406 3606 1284 -180 531 6862 2803 -841
407 3635 1296 -184 532 6886 2815 -848
408 3664 1307 -187 533 6910 2828 -855
409 3693 1319 -191 534 6933 2841 -862
410 3721 1331 -195 535 6957 2853 -869
411 3750 1343 -199 536 6981 2866 -876
412 3778 1354 -202 537 7004 2879 -883
413 3807 1366 -206 538 7028 2891 -890
414 3835 1378 -210 539 7051 2904 -897
415 3864 1390 -214 540 7075 2917 -904
416 3892 1401 -218 541 7098 2929 -911
417 3920 1413 -222 542 7122 2942 -918
418 3948 1425 -226 543 7145 2955 -925
419 3977 1437 -230 544 7168 2967 -932
420 4005 1449 -234 545 7192 2980 -939
421 4033 1460 -238 546 7215 2993 -947
422 4061 1472 -242 547 7238 3005 -954
423 4089 1484 -246 548 7261 3018 -961
424 4117 1496 -250 549 7285 3031 -968
425 4145 1508 -254 550 7308 3044 -976
426 4172 1519 -258 551 7331 3056 -983
427 4200 1531 -262 552 7354 3069 -990
428 4228 1543 -266 553 7377 3082 -998
429 4256 1555 -271 554 7400 3095 -1005
430 4283 1567 -275 555 7423 3107 -1013
431 4311 1579 -279 556 7446 3120 -1020
432 4338 1591 -284 557 7469 3133 -1027
433 4366 1603 -288 558 7492 3146 -1035
434 4393 1614 -292 559 7515 3159 -1042
435 4421 1626 -297 560 7538 3171 -1050
436 4448 1638 -301 561 7561 3184 -1058
437 4475 1650 -306 562 7584 3197 -1065
438 4503 1662 -310 563 7607 3210 -1073
439 4530 1674 -315 564 7629 3223 -1080
440 4557 1686 -319 565 7652 3235 -1088
441 4584 1698 -324 566 7675 3248 -1096
442 4611 1710 -328 567 7697 3261 -1103
443 4638 1722 -333 568 7720 3274 -1111
444 4665 1734 -338 569 7743 3287 -1119
445 4692 1746 -342 570 7765 3300 -1126
131
446 4719 1758 -347 571 7788 3313 -1134
447 4746 1770 -352 572 7811 3326 -1142
448 4773 1782 -356 573 7833 3338 -1150
449 4800 1794 -361 574 7856 3351 -1158
450 4826 1806 -366 575 7878 3364 -1166
451 4853 1818 -371 576 7901 3377 -1173
452 4880 1830 -376 577 7923 3390 -1181
453 4906 1842 -381 578 7945 3403 -1189
454 4933 1854 -386 579 7968 3416 -1197
455 4959 1866 -391 580 7990 3429 -1205
456 4986 1878 -396 581 8012 3442 -1213
457 5012 1890 -401 582 8035 3455 -1221
458 5039 1902 -406 583 8057 3468 -1229
459 5065 1914 -411 584 8079 3481 -1237
460 5091 1926 -416 585 8101 3494 -1245
461 5118 1938 -421 586 8124 3507 -1254
462 5144 1951 -426 587 8146 3520 -1262
463 5170 1963 -431 588 8168 3533 -1270
464 5196 1975 -436 589 8190 3546 -1278
465 5222 1987 -441 590 8212 3559 -1286
466 5248 1999 -447 591 8234 3572 -1294
467 5274 2011 -452 592 8256 3585 -1303
468 5300 2023 -457 593 8278 3598 -1311
469 5326 2035 -463 594 8300 3611 -1319
470 5352 2048 -468 595 8322 3624 -1328
471 5378 2060 -473 596 8344 3637 -1336
472 5404 2072 -479 597 8366 3650 -1344
473 5430 2084 -484 598 8388 3663 -1353
474 5455 2096 -490 599 8410 3676 -1361
475 5481 2108 -495 600 8432 3690 -1369
476 5507 2121 -500 601 8454 3703 -1378
477 5532 2133 -506 602 8475 3716 -1386
478 5558 2145 -512 603 8497 3729 -1395
479 5583 2157 -517 604 8519 3742 -1403
480 5609 2170 -523 605 8541 3755 -1412
481 5634 2182 -528 606 8562 3768 -1420
482 5660 2194 -534 607 8584 3781 -1429
483 5685 2206 -540 608 8606 3795 -1438
484 5710 2219 -545 609 8627 3808 -1446
485 5736 2231 -551 610 8649 3821 -1455
132
486 5761 2243 -557 611 8670 3834 -1464
487 5786 2255 -563 612 8692 3847 -1472
488 5812 2268 -568 613 8713 3860 -1481
489 5837 2280 -574 614 8735 3874 -1490
490 5862 2292 -580 615 8756 3887 -1498
491 5887 2305 -586 616 8778 3900 -1507
492 5912 2317 -592 617 8799 3913 -1516
493 5937 2329 -598 618 8821 3926 -1525
494 5962 2342 -604 619 8842 3940 -1534
495 5987 2354 -610 620 8864 3953 -1542
496 6012 2366 -616 621 8885 3966 -1551
497 6037 2379 -622 622 8906 3979 -1560
498 6062 2391 -628 623 8928 3993 -1569
499 6086 2403 -634 62315 8931 3995 -1570
133
Appendix G
Table G1 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid I state (29815-33715K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 319 578 162 -004
299 024 000 000 320 606 170 -005
300 052 000 000 321 633 179 -005
301 080 007 000 322 660 188 -006
302 108 016 000 323 688 197 -007
303 136 024 000 324 715 205 -007
304 164 032 000 325 742 214 -008
305 192 041 000 326 769 223 -009
306 219 049 000 327 796 232 -009
307 247 058 000 328 823 241 -010
308 275 067 -001 329 851 250 -011
309 303 075 -001 330 878 259 -011
310 330 084 -001 331 905 268 -012
311 358 092 -001 332 932 277 -013
312 386 101 -002 333 959 285 -014
313 413 109 -002 334 985 294 -015
314 441 118 -002 335 1012 303 -016
315 468 127 -003 336 1039 312 -017
316 496 135 -003 337 1066 321 -018
317 523 144 -003 33715 1070 331 -019
318 551 153 -004
Table G2 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid II state (36115-36415K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36115 2433 825 -054
134
362 2454 832 -056
363 2478 841 -059
364 2503 850 -061
36415 2506 851 -062
Table G3 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
liquid state (41115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
41115 3833 1366 -210 518 6604 2649 -772
412 3857 1376 -213 519 6628 2661 -778
413 3885 1387 -217 520 6652 2674 -785
414 3913 1399 -221 521 6675 2686 -792
415 3941 1411 -225 522 6699 2699 -798
416 3969 1422 -229 523 6723 2711 -805
417 3997 1434 -233 524 6747 2723 -812
418 4025 1446 -237 525 6770 2736 -819
419 4053 1457 -241 526 6794 2748 -825
420 4081 1469 -245 527 6818 2761 -832
421 4109 1481 -249 528 6841 2773 -839
422 4137 1493 -253 529 6865 2786 -846
423 4165 1504 -257 530 6888 2798 -853
424 4192 1516 -262 531 6912 2810 -860
425 4220 1528 -266 532 6935 2823 -867
426 4248 1539 -270 533 6959 2835 -873
427 4275 1551 -274 534 6982 2848 -880
428 4303 1563 -279 535 7005 2860 -887
429 4330 1575 -283 536 7029 2873 -894
430 4358 1587 -287 537 7052 2885 -902
431 4385 1598 -292 538 7075 2898 -909
432 4412 1610 -296 539 7098 2910 -916
433 4439 1622 -300 540 7122 2923 -923
434 4467 1634 -305 541 7145 2935 -930
135
435 4494 1646 -309 542 7168 2948 -937
436 4521 1657 -314 543 7191 2960 -944
437 4548 1669 -318 544 7214 2973 -951
438 4575 1681 -323 545 7237 2986 -959
439 4602 1693 -328 546 7260 2998 -966
440 4629 1705 -332 547 7283 3011 -973
441 4656 1716 -337 548 7306 3023 -980
442 4683 1728 -341 549 7329 3036 -988
443 4710 1740 -346 550 7352 3048 -995
444 4736 1752 -351 551 7375 3061 -1003
445 4763 1764 -356 552 7398 3074 -1010
446 4790 1776 -360 553 7420 3086 -1017
447 4816 1788 -365 554 7443 3099 -1025
448 4843 1800 -370 555 7466 3111 -1032
449 4869 1812 -375 556 7489 3124 -1040
450 4896 1823 -380 557 7511 3137 -1047
451 4922 1835 -385 558 7534 3149 -1055
452 4949 1847 -390 559 7557 3162 -1062
453 4975 1859 -395 560 7579 3175 -1070
454 5002 1871 -400 561 7602 3187 -1077
455 5028 1883 -405 562 7625 3200 -1085
456 5054 1895 -410 563 7647 3213 -1093
457 5080 1907 -415 564 7670 3225 -1100
458 5106 1919 -420 565 7692 3238 -1108
459 5132 1931 -425 566 7714 3251 -1116
460 5159 1943 -430 567 7737 3263 -1123
461 5185 1955 -435 568 7759 3276 -1131
462 5211 1967 -440 569 7782 3289 -1139
463 5236 1979 -446 570 7804 3302 -1147
464 5262 1991 -451 571 7826 3314 -1155
465 5288 2003 -456 572 7849 3327 -1162
466 5314 2015 -461 573 7871 3340 -1170
467 5340 2027 -467 574 7893 3352 -1178
468 5366 2039 -472 575 7915 3365 -1186
469 5391 2051 -478 576 7937 3378 -1194
470 5417 2063 -483 577 7960 3391 -1202
471 5442 2075 -488 578 7982 3404 -1210
472 5468 2087 -494 579 8004 3416 -1218
473 5494 2099 -499 580 8026 3429 -1226
474 5519 2111 -505 581 8048 3442 -1234
136
475 5545 2123 -510 582 8070 3455 -1242
476 5570 2135 -516 583 8092 3468 -1250
477 5595 2147 -521 584 8114 3480 -1258
478 5621 2160 -527 585 8136 3493 -1266
479 5646 2172 -533 586 8158 3506 -1274
480 5671 2184 -538 587 8180 3519 -1283
481 5696 2196 -544 588 8201 3532 -1291
482 5722 2208 -550 589 8223 3545 -1299
483 5747 2220 -555 590 8245 3557 -1307
484 5772 2232 -561 591 8267 3570 -1315
485 5797 2244 -567 592 8289 3583 -1324
486 5822 2257 -573 593 8310 3596 -1332
487 5847 2269 -579 594 8332 3609 -1340
488 5872 2281 -585 595 8354 3622 -1349
489 5897 2293 -590 596 8375 3635 -1357
490 5922 2305 -596 597 8397 3648 -1365
491 5947 2317 -602 598 8419 3660 -1374
492 5971 2330 -608 599 8440 3673 -1382
493 5996 2342 -614 600 8462 3686 -1391
494 6021 2354 -620 601 8483 3699 -1399
495 6046 2366 -626 602 8505 3712 -1408
496 6070 2379 -632 603 8526 3725 -1416
497 6095 2391 -638 604 8548 3738 -1425
498 6119 2403 -645 605 8569 3751 -1433
499 6144 2415 -651 606 8591 3764 -1442
500 6169 2427 -657 607 8612 3777 -1451
501 6193 2440 -663 608 8633 3790 -1459
502 6217 2452 -669 609 8655 3803 -1468
503 6242 2464 -675 610 8676 3816 -1476
504 6266 2477 -682 611 8697 3829 -1485
505 6291 2489 -688 612 8719 3842 -1494
506 6315 2501 -694 613 8740 3855 -1503
507 6339 2513 -701 614 8761 3868 -1511
508 6363 2526 -707 615 8782 3881 -1520
509 6388 2538 -713 616 8803 3894 -1529
510 6412 2550 -720 617 8825 3907 -1538
511 6436 2563 -726 618 8846 3920 -1547
512 6460 2575 -733 619 8867 3933 -1555
513 6484 2587 -739 620 8888 3946 -1564
514 6508 2600 -746 621 8909 3959 -1573
137
515 6532 2612 -752 622 8930 3972 -1582
516 6556 2624 -759 623 8951 3985 -1591
517 6580 2637 -765 62315 8954 3987 -1592
138
Appendix H
Table H1 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid I
state (29815-35415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 768 241 -011
299 023 007 000 328 794 249 -011
300 050 015 000 329 820 258 -012
301 077 023 000 330 846 266 -013
302 104 031 000 331 872 275 -014
303 131 039 000 332 898 284 -015
304 158 048 000 333 924 292 -016
305 185 056 -001 334 950 301 -016
306 212 064 -001 335 976 310 -017
307 239 072 -001 336 1002 318 -018
308 265 081 -001 337 1028 327 -019
309 292 089 -001 338 1053 336 -020
310 319 097 -002 339 1079 344 -021
311 345 105 -002 340 1105 353 -022
312 372 114 -002 341 1130 362 -024
313 399 122 -003 342 1156 371 -025
314 425 130 -003 343 1182 379 -026
315 452 139 -004 344 1207 388 -027
316 478 147 -004 345 1233 397 -028
317 505 156 -004 346 1258 406 -029
318 531 164 -005 347 1284 415 -031
319 558 172 -005 348 1309 424 -032
320 584 181 -006 349 1335 433 -033
321 611 189 -007 350 1360 441 -035
322 637 198 -007 351 1385 450 -036
323 663 206 -008 352 1411 459 -037
324 689 215 -008 353 1436 468 -039
325 716 223 -009 354 1461 477 -040
326 742 232 -010 35415 1465 478 -040
139
Table H2 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid 2
state (36215-37315K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36215 2387 777 -046
363 2408 809 -055
364 2432 817 -057
365 2457 826 -060
366 2481 835 -062
367 2506 843 -065
368 2530 852 -067
369 2555 861 -070
370 2579 870 -072
371 2604 879 -075
372 2628 888 -077
373 2653 898 -080
37315 2657 907 -083
Table H3 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in liquid
state (37915-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37915 2966 1025 -100 502 6174 2432 -667
380 2991 1034 -102 503 6198 2444 -674
381 3020 1045 -105 504 6222 2456 -680
382 3048 1056 -108 505 6246 2468 -686
383 3077 1067 -112 506 6270 2480 -692
384 3105 1078 -115 507 6294 2492 -699
385 3134 1089 -118 508 6317 2504 -705
386 3162 1100 -121 509 6341 2516 -711
387 3191 1111 -124 510 6365 2528 -718
140
388 3219 1122 -127 511 6388 2541 -724
389 3247 1133 -130 512 6412 2553 -730
390 3275 1144 -134 513 6436 2565 -737
391 3304 1155 -137 514 6459 2577 -743
392 3332 1166 -140 515 6483 2589 -750
393 3360 1177 -144 516 6506 2601 -756
394 3388 1188 -147 517 6530 2613 -763
395 3416 1199 -150 518 6553 2625 -769
396 3444 1210 -154 519 6577 2638 -776
397 3472 1221 -157 520 6600 2650 -782
398 3500 1232 -161 521 6624 2662 -789
399 3527 1243 -164 522 6647 2674 -796
400 3555 1254 -168 523 6670 2686 -802
401 3583 1265 -171 524 6694 2698 -809
402 3611 1276 -175 525 6717 2711 -816
403 3638 1287 -179 526 6740 2723 -822
404 3666 1299 -182 527 6763 2735 -829
405 3693 1310 -186 528 6786 2747 -836
406 3721 1321 -190 529 6810 2760 -843
407 3748 1332 -193 530 6833 2772 -850
408 3776 1343 -197 531 6856 2784 -856
409 3803 1354 -201 532 6879 2796 -863
410 3830 1366 -205 533 6902 2809 -870
411 3857 1377 -209 534 6925 2821 -877
412 3885 1388 -213 535 6948 2833 -884
413 3912 1399 -216 536 6971 2845 -891
414 3939 1410 -220 537 6994 2858 -898
415 3966 1422 -224 538 7017 2870 -905
416 3993 1433 -228 539 7040 2882 -912
417 4020 1444 -232 540 7063 2895 -919
418 4047 1455 -236 541 7086 2907 -926
419 4074 1467 -240 542 7108 2919 -933
420 4101 1478 -245 543 7131 2932 -940
421 4128 1489 -249 544 7154 2944 -947
422 4154 1500 -253 545 7177 2957 -955
423 4181 1512 -257 546 7199 2969 -962
424 4208 1523 -261 547 7222 2981 -969
425 4234 1534 -265 548 7245 2994 -976
426 4261 1546 -270 549 7267 3006 -984
427 4288 1557 -274 550 7290 3019 -991
141
428 4314 1568 -278 551 7313 3031 -998
429 4341 1580 -282 552 7335 3044 -1005
430 4367 1591 -287 553 7358 3056 -1013
431 4393 1602 -291 554 7380 3068 -1020
432 4420 1614 -296 555 7403 3081 -1028
433 4446 1625 -300 556 7425 3093 -1035
434 4472 1636 -305 557 7448 3106 -1042
435 4499 1648 -309 558 7470 3118 -1050
436 4525 1659 -314 559 7492 3131 -1057
437 4551 1671 -318 560 7515 3143 -1065
438 4577 1682 -323 561 7537 3156 -1072
439 4603 1694 -327 562 7560 3169 -1080
440 4629 1705 -332 563 7582 3181 -1087
441 4655 1716 -336 564 7604 3194 -1095
442 4681 1728 -341 565 7626 3206 -1103
443 4707 1739 -346 566 7649 3219 -1110
444 4733 1751 -351 567 7671 3231 -1118
445 4759 1762 -355 568 7693 3244 -1126
446 4785 1774 -360 569 7715 3257 -1133
447 4810 1785 -365 570 7737 3269 -1141
448 4836 1797 -370 571 7759 3282 -1149
449 4862 1808 -375 572 7782 3294 -1157
450 4888 1820 -379 573 7804 3307 -1164
451 4913 1832 -384 574 7826 3320 -1172
452 4939 1843 -389 575 7848 3332 -1180
453 4964 1855 -394 576 7870 3345 -1188
454 4990 1866 -399 577 7892 3358 -1196
455 5015 1878 -404 578 7914 3370 -1204
456 5041 1889 -409 579 7936 3383 -1212
457 5066 1901 -414 580 7957 3396 -1220
458 5092 1913 -419 581 7979 3408 -1228
459 5117 1924 -424 582 8001 3421 -1236
460 5142 1936 -430 583 8023 3434 -1244
461 5167 1947 -435 584 8045 3447 -1252
462 5193 1959 -440 585 8067 3459 -1260
463 5218 1971 -445 586 8088 3472 -1268
464 5243 1982 -450 587 8110 3485 -1276
465 5268 1994 -456 588 8132 3498 -1284
466 5293 2006 -461 589 8154 3510 -1292
467 5318 2017 -466 590 8175 3523 -1300
142
468 5343 2029 -472 591 8197 3536 -1308
469 5368 2041 -477 592 8219 3549 -1317
470 5393 2053 -482 593 8240 3562 -1325
471 5418 2064 -488 594 8262 3574 -1333
472 5443 2076 -493 595 8283 3587 -1341
473 5468 2088 -499 596 8305 3600 -1350
474 5493 2100 -504 597 8327 3613 -1358
475 5517 2111 -510 598 8348 3626 -1366
476 5542 2123 -515 599 8370 3639 -1375
477 5567 2135 -521 600 8391 3652 -1383
478 5592 2147 -526 601 8413 3664 -1391
479 5616 2158 -532 602 8434 3677 -1400
480 5641 2170 -537 603 8455 3690 -1408
481 5665 2182 -543 604 8477 3703 -1417
482 5690 2194 -549 605 8498 3716 -1425
483 5715 2206 -554 606 8520 3729 -1434
484 5739 2218 -560 607 8541 3742 -1442
485 5763 2229 -566 608 8562 3755 -1451
486 5788 2241 -572 609 8583 3768 -1459
487 5812 2253 -578 610 8605 3781 -1468
488 5837 2265 -583 611 8626 3794 -1477
489 5861 2277 -589 612 8647 3807 -1485
490 5885 2289 -595 613 8668 3820 -1494
491 5910 2301 -601 614 8690 3833 -1503
492 5934 2313 -607 615 8711 3846 -1511
493 5958 2324 -613 616 8732 3859 -1520
494 5982 2336 -619 617 8753 3872 -1529
495 6006 2348 -625 618 8774 3885 -1538
496 6030 2360 -631 619 8795 3898 -1546
497 6055 2372 -637 620 8816 3911 -1555
498 6079 2384 -643 621 8837 3924 -1564
499 6103 2396 -649 622 8858 3937 -1573
500 6127 2408 -655 623 8879 3950 -1582
501 6151 2420 -661 62315 8883 3952 -1583
143
Appendix I
Table I1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in solid state (29815-35315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 1171 366 -017
299 035 010 000 328 1211 379 -018
300 076 023 000 329 1250 392 -019
301 117 035 000 330 1290 405 -021
302 158 048 000 331 1330 418 -022
303 199 060 000 332 1369 431 -023
304 240 072 -001 333 1409 444 -025
305 281 085 -001 334 1448 458 -026
306 322 097 -001 335 1488 471 -028
307 363 110 -002 336 1527 484 -029
308 404 122 -002 337 1566 497 -031
309 445 135 -002 338 1605 510 -032
310 486 148 -003 339 1644 524 -034
311 526 160 -003 340 1683 537 -036
312 567 173 -004 341 1722 550 -037
313 608 186 -005 342 1761 563 -039
314 648 198 -005 343 1800 577 -041
315 689 211 -006 344 1839 590 -043
316 729 224 -007 345 1877 603 -044
317 770 237 -007 346 1916 617 -046
318 810 250 -008 347 1955 630 -048
319 850 262 -009 348 1993 643 -050
320 891 275 -010 349 2031 657 -052
321 931 288 -011 350 2070 670 -054
322 971 301 -012 351 2108 683 -056
323 1011 314 -013 352 2146 697 -059
324 1051 327 -014 353 2184 710 -061
325 1091 340 -015 35315 2190 712 -061
326 1131 353 -016
144
Table I2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in liquid state (39115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
39115 4413 1056 -191 508 8890 3521 -978
392 4450 1535 -195 509 8924 3538 -986
393 4492 1549 -200 510 8959 3556 -995
394 4535 1566 -204 511 8993 3574 -1004
395 4577 1583 -209 512 9027 3591 -1013
396 4620 1599 -213 513 9062 3609 -1022
397 4662 1616 -218 514 9096 3626 -1031
398 4704 1633 -223 515 9130 3644 -1041
399 4746 1650 -227 516 9164 3661 -1050
400 4789 1666 -232 517 9198 3679 -1059
401 4831 1683 -237 518 9232 3697 -1068
402 4872 1700 -242 519 9266 3714 -1077
403 4914 1717 -247 520 9300 3732 -1087
404 4956 1734 -252 521 9334 3750 -1096
405 4997 1751 -257 522 9368 3767 -1105
406 5039 1767 -262 523 9402 3785 -1115
407 5080 1784 -267 524 9435 3802 -1124
408 5122 1801 -272 525 9469 3820 -1134
409 5163 1818 -277 526 9503 3838 -1143
410 5204 1835 -282 527 9536 3855 -1152
411 5245 1852 -287 528 9570 3873 -1162
412 5286 1869 -293 529 9603 3891 -1172
413 5327 1885 -298 530 9637 3908 -1181
414 5368 1902 -303 531 9670 3926 -1191
415 5409 1919 -309 532 9703 3944 -1201
416 5450 1936 -314 533 9737 3962 -1210
417 5490 1953 -320 534 9770 3979 -1220
418 5531 1970 -325 535 9803 3997 -1230
419 5571 1987 -331 536 9836 4015 -1240
420 5612 2004 -336 537 9869 4032 -1249
421 5652 2021 -342 538 9902 4050 -1259
145
422 5692 2038 -347 539 9935 4068 -1269
423 5732 2055 -353 540 9968 4086 -1279
424 5772 2072 -359 541 10001 4104 -1289
425 5812 2089 -365 542 10034 4121 -1299
426 5852 2106 -371 543 10066 4139 -1309
427 5892 2123 -376 544 10099 4157 -1319
428 5932 2140 -382 545 10132 4175 -1329
429 5971 2157 -388 546 10165 4192 -1340
430 6011 2174 -394 547 10197 4210 -1350
431 6051 2191 -400 548 10230 4228 -1360
432 6090 2208 -406 549 10262 4246 -1370
433 6129 2225 -412 550 10295 4264 -1380
434 6169 2242 -419 551 10327 4282 -1391
435 6208 2259 -425 552 10359 4299 -1401
436 6247 2276 -431 553 10392 4317 -1411
437 6286 2293 -437 554 10424 4335 -1422
438 6325 2310 -444 555 10456 4353 -1432
439 6364 2327 -450 556 10488 4371 -1443
440 6403 2344 -456 557 10520 4389 -1453
441 6442 2361 -463 558 10553 4407 -1464
442 6480 2378 -469 559 10585 4424 -1474
443 6519 2395 -476 560 10617 4442 -1485
444 6557 2412 -482 561 10648 4460 -1496
445 6596 2429 -489 562 10680 4478 -1506
446 6634 2446 -495 563 10712 4496 -1517
447 6673 2464 -502 564 10744 4514 -1528
448 6711 2481 -509 565 10776 4532 -1538
449 6749 2498 -515 566 10808 4550 -1549
450 6787 2515 -522 567 10839 4568 -1560
451 6825 2532 -529 568 10871 4586 -1571
452 6863 2549 -536 569 10902 4604 -1582
453 6901 2566 -543 570 10934 4622 -1593
454 6939 2584 -550 571 10965 4640 -1604
455 6977 2601 -557 572 10997 4658 -1615
456 7015 2618 -564 573 11028 4676 -1626
457 7052 2635 -571 574 11060 4694 -1637
458 7090 2652 -578 575 11091 4712 -1648
459 7128 2670 -585 576 11122 4730 -1659
460 7165 2687 -592 577 11154 4748 -1670
461 7202 2704 -599 578 11185 4766 -1681
146
462 7240 2721 -606 579 11216 4784 -1692
463 7277 2738 -614 580 11247 4802 -1704
464 7314 2756 -621 581 11278 4820 -1715
465 7351 2773 -628 582 11309 4838 -1726
466 7388 2790 -636 583 11340 4856 -1737
467 7425 2807 -643 584 11371 4874 -1749
468 7462 2825 -650 585 11402 4892 -1760
469 7499 2842 -658 586 11433 4910 -1772
470 7536 2859 -665 587 11464 4928 -1783
471 7573 2877 -673 588 11495 4946 -1794
472 7609 2894 -680 589 11525 4964 -1806
473 7646 2911 -688 590 11556 4982 -1817
474 7682 2928 -696 591 11587 5001 -1829
475 7719 2946 -703 592 11617 5019 -1841
476 7755 2963 -711 593 11648 5037 -1852
477 7792 2980 -719 594 11678 5055 -1864
478 7828 2998 -727 595 11709 5073 -1876
479 7864 3015 -735 596 11739 5091 -1887
480 7900 3032 -742 597 11770 5109 -1899
481 7937 3050 -750 598 11800 5128 -1911
482 7973 3067 -758 599 11831 5146 -1923
483 8009 3084 -766 600 11861 5164 -1935
484 8045 3102 -774 601 11891 5182 -1946
485 8080 3119 -782 602 11921 5200 -1958
486 8116 3137 -791 603 11952 5218 -1970
487 8152 3154 -799 604 11982 5237 -1982
488 8188 3171 -807 605 12012 5255 -1994
489 8223 3189 -815 606 12042 5273 -2006
490 8259 3206 -823 607 12072 5291 -2018
491 8294 3224 -832 608 12102 5309 -2030
492 8330 3241 -840 609 12132 5328 -2042
493 8365 3259 -848 610 12162 5346 -2055
494 8401 3276 -857 611 12192 5364 -2067
495 8436 3293 -865 612 12222 5382 -2079
496 8471 3311 -873 613 12252 5401 -2091
497 8506 3328 -882 614 12281 5419 -2103
498 8542 3346 -890 615 12311 5437 -2116
499 8577 3363 -899 616 12341 5456 -2128
500 8612 3381 -908 617 12370 5474 -2140
501 8647 3398 -916 618 12400 5492 -2153
147
502 8681 3416 -925 619 12430 5510 -2165
503 8716 3433 -934 620 12459 5529 -2178
504 8751 3451 -942 621 12489 5547 -2190
505 8786 3468 -951 622 12518 5565 -2203
506 8820 3486 -960 623 12548 5584 -2215
507 8855 3503 -969 62315 12552 5602 -2217
v
TABLE OF CONTENTS
ABSTRACT ii
DEDICATION iii
ACKNOWLEDGEMENTS iv
LIST OF TABLES viii
LIST OF FIGURES x
CHAPTER 1 INTRODUCTION 1
CHAPTER 2 LITERATURE REVIEW 11
21 Melting point 11
22 Density 15
23 Heat capacity 18
CHAPTER 3 OBJECTIVES 22
CHAPTER 4 THERMODYNAMIC MODELING OF SALT SYSTEMS 24
41 Thermodynamic modeling 24
42 Calculations 27
vi
CHAPTER 5 EXPERIMENTAL PROCEDURE 30
51 Melting point determination of molten salt mixtures 30
511 Materials 30
512 Apparatus and Procedure 30
52 Heat Capacity determination of molten salt mixtures 32
53 Density determination of molten salt mixtures 33
CHAPTER 6 RESULT AND DISCUSSION 34
61 Melting point determination 34
611 DSC equipment calibration 34
612 Results 35
613 Discussion 41
62 Heat capacity determination 51
621 Heat capacity calibration 51
622 Results 52
623 Thermodynamic properties 55
624 Discussion of Gibbs energy change for molten salts 84
63 Density determination 86
vii
631 Density calibration 86
632 Results and discussions 82
64 Thermal energy storage density of molten salts 90
CHAPTER 7 CONCLUSION 94
REFERENCES 96
APPENDIX 104
APPENDIX A 104
APPENDIX B 109
APPENDIX C 114
APPENDIX D 118
APPENDIX E 123
APPENDIX F 128
APPENDIX G 133
APPENDIX H 138
APPENDIX I 143
viii
LIST OF TABLES
21 Melting point of various nitrate salt systems 12
22 Melting point of various carbonate salt systems 13
23 Melting point of various fluoridechloride salt systems 14
24 Melting point of various hydroixde salt systems 15
25 Density coefficients A and B of nitrate salts 16
26 Density coefficients A and B of carbonate salts 17
27 Density coefficients A and B of chloridefluoride salts 17
28 Density coefficients A and B of molten salt mixture with hydroxide salts 18
29 Heat capacity of alkali nitrate salt at 500oC 19
210 Heat capacity of alkali carbonate salt at 500oC 19
211 Heat capacity of fluoridechloride salt at 500oC 20
212 Heat capacity of hydroxide salt at 500oC 21
41 Calculated composition and melting point for multi-component systems 29
61 Calibration data of melting points with different samples 35
62 DSC results of melting point transition point and change of enthalpy 41
ix
63 Fusion and solid phase transition temperature for individual salts 42
64 Melting points of candidate systems as function of temperatures 51
65 Calibration data of heat capacities with different samples 52
66 Heat capacity of selected new TES molten salt mixtures 54
67 Change of Gibbs energy values at 62315K for molten salt systems 85
68 Calibration of density measurements with different pure nitrate salts 86
69 Coefficient of A and B for density determination of salt 1 to salt 9 87
610 Extrapolated value of density and heat capacity at 500oC of salt 1 to salt 9 91
611 Energy density of salt 1 to salt 9 compare to solar salt 92
612 Gravimetric storage densities for solar salt and new molten salts 93
x
LIST OF FIGURES
11 Theoretical and engineering energy conversion efficiency as function of temperature 6
12 Gravimetric storage density for different energy storage systems
as function of temperature 8
51 Photography of set-up for DSC equipment 31
61 Melting point calibration with indium sample 34
62 Melting point calibration with KNO3 sample 35
63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt 36
64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt 37
65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt 37
66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt 38
67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt 38
68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt 39
69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt 39
610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt 40
611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN Salt 40
612 DSC plot of 698wt KNO3 -302wt NaNO2 binary system 43
xi
613 DSC plot of 270wt NaNO3-730wt KNO3 binary system 45
614 DSC plot of 458wtLiNO3-542wtKNO3 binary system 45
615 DSC plot of 460wt NaNO3-540wt KNO3 binary system 46
616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 20oCmin heating rate 47
616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 5oCmin heating rate 48
617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 5oCmin heating rate 49
617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 20oCmin heating rate 49
618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system
as function of temperature 53
619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K 54
620 Change of Gibbs energy as function of temperature for molten salt systems 85
621 The densities of the salt 1 to salt 5 as function of temperature 87
622 The densities of the salt 6 to salt 9 as function of temperature 89
623 Densities of the salt 1 salt 2 as function of temperature compared to
the equimolar NaNO3-KNO3 binary system and pure KNO3 90
624 Gravimetric storage density comparison of different energy storage
xii
systems as function of temperature 93
1
CHAPTER 1
INTRODUCTION
Renewable energy sources such as wind solar water power geothermal and biomass are
playing more and more significant role in our energy supply Because the cheap cost and infinite
amount of energy storage inside the resource solar energy is emphasized since 20th
century and
viewed as promising alternative method to satisfy the large energy consumption every day in the
world reduce the emission of carbon and strengthen the economy
The wind energy was used as a clean energy to generate electricity back to late 19th
century
However this renewable energy source was not emphasized due to the cheap price of fossil fuel
The re-emergence happened in mid 1950s when the amount of traditional energy source was
found apparently decrease The development of wind energy usage continued and in 1990 the
first mega-watt wind turbine was launched which was viewed as a symbol of shift to large scale
wind energy utilization [1-2] The modern application of wind energy mainly relies on wind
turbine On the basis of aerodynamic wind turbine generates certain net positive torque on
rotating shaft and then converts the mechanical power to electrical power As an electrical power
generator wind turbine is connected to some electrical network to transport the electricity to
battery charging utilities residential power systems and large scale energy consuming systems
In general most of wind turbines are small scale and can only generate 10KW electrical power
Only few of the wind turbine systems operate with capacity as large as 5MW Although the
usage of wind energy can reduce the emission of carbon oxide the noise pollution and high cost
2
limit its large scale application Since the wind is not transportable the electrical energy can only
be generated where the wind blows which also decrease the flexibility of wind energy
Water power is another term of alternative power supply and it was used for irrigation
operating machines like watermill even before the development of electrical power The modern
application of water power is to generate electricity by using the gravitational force of falling or
flowing water These days there are various ways for the water power application The most
traditional method is to store the water in dam and generate electricity by converting the
potential energy pump storage is a different way to utilize water power and can change its
output depending on the energy demand by moving water between reservoirs at different
elevations In the low energy demand period excess energy is used to lift water to the higher
level while in the peak period of energy demand the water is released back to the lower
elevation through water turbine Water power can also be converted by taking advantage of
naturally raise and fall of tide to satisfy the demand of electrical energy consumption [3]
Although the usage of water power can reduce the emission of carbon dioxide and cost it will
destroy the ecosystem because of the large land required for construction There will be methane
emission from the reservoir the potential failure hazard of dam is also a fatal issue and flow
shortage caused by drought may also create serious problem As result of that water power
technique is not a long-term alternative choice
Geothermal energy is the energy form generated inside the earth At the very beginning of
the planet formation a large amount of thermal energy was stored from the radioactive decay of
minerals volcanic activity and solar energy absorption Because of the temperature difference
3
between the core and the surface of planet the thermal energy stored inside the earth is driven to
the outer surface in the form of heat This form of renewable energy source can be applied to
generate electrical power and heat for industrial space and agricultural applications
Theoretically the deposited amount of geothermal energy is adequate to supply the energy
consumption in the world However most of the geothermal energy is stored deeply near the
core of the earth the deep drilling and exploration of geothermal energy is very expensive and
limits the large-scale use of this renewable energy source [4]
Biomass is a renewable energy source used to generate heat or electricity with living or
recently living organism such as wood waste (hydrogen) gas and alcohol fuels The biomass
energy can be converted to electrical energy by thermal method such as combustion pyrolysis
and gasification Several specific chemical processes may also be able to convert the biomass
energy to other forms The main problem arise from application of biomass is air pollution which
contains carbon monoxide NOx (nitrogen oxides) VOCs (volatile organic compounds)
particulates and other pollutants And the level of air pollution to some extent is even above that
of traditional fuel resource Some other possible issue like transportation and sink of carbon also
limit the wide usage of this type of alternative energy [5]
Among all the renewable energy sources solar energy is the most suitable alternative
energy for our future life It is clean cheap abundant without any noise air pollution no
transportation issue and easy to be obtained anywhere in the earth Inside the core of the Sun
hydrogen fuses into helium with a rate of 7times1011
kgs and generates very powerful nucleation
power This type of nucleation explosion creates ultra high temperature in the core of the Sun
4
which reaches approximately 16 million K degrees Although the Sun is not perfectly black body
it still radiates abundant power with the energy density as 16times107 wattsm
2 [6-7] Because of the
enough amount of hydrogen underneath the surface of the Sun the radiation given arise of from
the nucleation explosion can continue at least 5 million years with the same rate and strength
The energy reaching the earth is vastly reduced mainly caused by the absorption and spreading
of the radiation It is easily to understand that there are numerous amorphous objects all around
the entire universe which can absorb certain portion of the radiation for the Sun Moreover the
light generated from the spherical object such as the Sun fills all the available space between the
origin to the destination Even though the energy will not be lost in the travelling process due to
the long distance between the Sun to the earth the surface area of the sphere which is formed
with the Sun as center and the distance as radius is much larger than that of the earth As the
result of that only 1340Wm2 finally reaches the upmost surface of the earth Even though the
final amount of the received solar energy is very small compared to that is initially radiated from
the Sun the average daily solar radiation falling on one area in the continental United States is
equivalent in total energy content to 11 barrels of oil In summary the solar energy itself is
relatively unlimited useful clean and almost unexploited energy and definitely can behave as
the promising mean for the future energy supply [8]
There are several different methods to take advantage of the solar energy and all the
methods can be distinguished into three group solar parabolic trough solar tower and solar dish
Parabolic trough is constructed by silver coated parabolic mirror and there is a Dewar tube going
through the length of the mirror and set on the focal point all the radiation is concentrated on the
tube and transfer by heat transfer fluid to the thermal energy storage unit Solar tower are used to
5
capture solar energy with thousands of mirrors and focus the concentrated sunlight to the top of
the tower which is located in the middle of the heliostats The thermal energy storage medium
within the tower was heated to high temperature and transferred to thermal energy storage tank
and eventually sent to steam pump The solar dish is built with a large reflective parabolic dish
which concentrates all the received sunlight to one spot There is normally a receiver located on
the focal point and transform the solar energy to other forms of useful energy The working
upper limit temperature of solar parabolic trough system is the lowest among these three systems
normally its maximum working temperature is within the range from 400-500oC the solar tower
has higher maximum working temperature which ranges from 500-1000oC the solar dish has the
highest working upper limit temperature which reaches 700-1200oC [9]
The energy conversion efficiency is the most concerned parameter in the solar energy
storage application and the theoretical and real engineering efficiency are given in fig 11 as
function of temperature The theoretical conversion efficiency can be up to 80 while in real
application the value is always less than 70 regardless of collectors The actual efficiency
increases with temperature in the whole working temperature As a result of that the thermal
energy storage materials in solar parabolic trough for instance should be able to work stably at
the upper limit temperature of this type of collection system which is 500oC to ensure the highest
efficiency [9 10]
6
Fig 11 Theoretical and engineering energy conversion efficiency as function of
temperature
Solar energy can be stored in three major forms sensible heat latent heat and
thermochemical heat Sensible heat storage was utilized based on the heat capacity and the
change as function of temperature of storage materials in the charging and discharging process
which correspond to the absorbing and withdrawing energy processes respectively The sensible
heat stored from the melting point to the maximum working temperature can be expressed by
equation 1 [9]
[1]
Where m is the mass of storage material Tmp and TH are melting point temperature and high
temperature in the same phase respectively Cp(T) is the heat capacity at different temperature
Because the sensible heat storage materials remain in a single phase in the working temperature
range the charging and discharging processes are completely reversible for unlimited cycles
7
Latent heat storage is operated by absorbing and withdrawing energy in the charging and
discharging processes accompanied with fusion of materials [9] The latent heat collected
throughout the working temperature range can be expressed by equation 2 as following
[2]
Where T is temperature in solid state Tmp is melting point temperature of storage material TH is
the high temperature in liquid state and is enthalpy of fusion
Thermochemical heat storage is based on the heat capacity and its change as function of
temperature accompanied with chemical reaction The thermochemical heat collected throughout
the working temperature range can be expressed by equation 3
[3]
Where TL is the low temperature before the reaction TR is the reaction temperature and
is the enthalpy of chemical reaction Because of the destruction of the chemical bonds
in the reaction process the charging and discharging process cannot be completely reversible
which reduces the stability and recyclability of storage operation [10]
Sensible energy storage method is chosen to ensure the efficient usage of solar energy for
parabolic trough system of which the maximum working temperature ranges from 400-500oC
Different from thermochemical heat storage the sensible heat storage can achieve completely
reversible working condition under unlimited cycles Also fig 12 illustrates that the sensible
heat storage materials mainly work in the working temperature range for parabolic trough system
8
and the gravimetric energy storage densities of sensible heat is higher than that of latent heat
materials [9 -11]
Fig 12 Gravimetric storage density for different energy storage systems as function of
temperature
Various materials are chosen to serve as thermal energy storage fluid for sensible heat
such as water thermal oil ionic liquid and molten salt [12] The properties of different heat
transfer fluid determine the performance of solar energy heating system In these days the
efficiency and cost of output of electrical power mainly relies on the parabolic trough solar
power plant and the thermal storage fluid [12] A large investment cost is needed to dispatch
100MW to 200MW energy by consuming the energy transfer fluids Given by this situation the
development of new thermal storage fluid with higher thermal energy storage density is
paramount to lower the expense for generating energy and a lot of effect has been put on design
of new systems [13-16]
9
Water is commonly used as heat transfer and thermal energy storage fluid in industry
because of its low cost high heat capacity and high thermal conductivity However the
limitation for using this medium is also obvious that the temperature range within which the
liquid state can be assured is too small It is well know that water can only serve as thermal
energy storage liquid above the freezing point 0oC and below the boiling temperature 100
oC In
practical experiment the actual temperature range is even less than 100oC because of the large
amount of weight loss near the boiling temperature due to the high vapor pressure Water is
possible to work above 100oC only if high pressure is also applied to avoid the phase
transformation but the cost will be highly increased Accordingly water is only suitable to work
in low temperature below 100oC
Thermal oils are also being used in the parabolic trough solar power plant and have very
low melting point as low as 12oC [17 18] However the application of the oil for the thermal
energy storage liquid is limited by some disadvantages from the physic-chemical properties The
upper limit for this oil is only 300oC and above that the liquid state cannot be maintained
Moreover the low thermal decomposition temperature low density and low heat capacity result
in limited thermal energy storage capacity Since the working temperature range is so narrow the
rankie cycle efficiency is reduced when using the synthetic oil and the cost for generating power
is considered to be very expensive [19 20]
Ionic liquid is another medium served as thermal energy storage fluid The liquid
temperature range of ionic liquid is large which is one of the main advantages of this type of
material The high heat capacity and density ensure the efficiency of thermal energy storage of
10
ionic liquid What‟s more the excellent chemical stability and little vapor pressure increase the
lifetime [21-24] However as a result of the very serve corrosion problem to the liquid container
and the high cost the usage of ionic liquid is still limited
Considering various relative physic-chemical properties of thermal energy storage system
molten salts have been proposed as a suitable group for a wide temperature range application
They are being emphasized in the solar energy applications because of their low melting point
and high upper limit which can increase the stable working range The high heat capacity
increases the thermal energy storage density of the heat storage system excellent thermal
stability and negligible vapor pressure ensure the steadiness of cyclic repeating in the lifetime
[25] low viscosity strengths the mobility and efficiency of the thermal storage liquid low
utilization cost reduce the investment and protect the economy The liquidus temperature range
of the molten salt varies from 150-600oC combination of various salts can bring the melting
down and further increase the working temperature range Due to these properties molten salts
can be excellent thermal energy storage fluid in the solar power generation system
11
CHAPTER 2
LITERATURE REVIEW
Several physical and thermodynamic properties of thermal energy storage fluid play
significant role in determining the efficiency and performance of solar energy storage systems In
order to evaluate the feasibility of systems the physic-chemical properties of several molten salts
should be reviewed The three determining parameter which directly affect the thermal energy
storage capacity in systems are melting point heat capacity and density
There are large amount of melting point data available in the literature for various molten
salt system in previous literatures while those with melting point less than 120oC is very limited
All the previous study on molten salt system revealed that five group of molten salts are
emphasized and commonly used alkai or alkaline nitrates carbonates sulphates chloride and
hydroxides Although most of the systems have the same group of cation the melting point
varies a lot from one to anther due to the different effect of anions
21 Melting point
The melting points of individual and multi-component nitratenitrite systems are listed in
Table 21[26-31] Among those systems solar salt (NaNO3KNO3 6040) is the thermal energy
storage medium which is currently being used with the freezing point of 221oC [27] Although
the melting point for this system is highest in all the candidate mixtures in this group the lowest
12
combined compound cost makes it widely used in solar energy storage field Another ternary
system HITEC which contains NaNO3 KNO3 and NaNO2 has freezing point of 141 oC [28]
This combination brings the melting point down but the lack of combination of optimum features
limits its further application [29] Some mixtures such as LiNO3-Ca(NO3)2-KNO3 are not often
utilized because they increase the compound cost at the same time of lowering the melting point
to around 120oC [30] moreover the decreased melting point is still high compared to the
organic oil There are also several systems have the melting points less than 100oC or even 60
oC
they are not used in the parabolic trough solar power plant due to the decomposition of some
components during high temperature [31]
Table 21 Melting point of various nitrate salt systems
Compound Melting Point (ordmC)
LiNO3 253
NaNO3 307
KNO3 334
Ca(NO3)2 561
Sr(NO3)2 570
Ba(NO3)2 590
NaNO3-NaNO2 221
NaNO3-NaNO2-KNO3 141
NaNO3-KNO3-CaNO3 133
LiNO3-KNO3-NaNO3 120
KNO3-CaNO3-LiNO3 117
LiNO3-KNO3-NHNO3 92
KNO3-NHNO3-AgNO3 52
The melting points of individual and multi-component carbonate systems are listed in
Table 22 [26 32 33] Different from the nitrate salts the melting points for both the individual
13
and multi-component carbonate systems are on the higher side The lowest melting point is
achieved with lithium sodium and potassium carbonate ternary system whose melting point is
still 277oC higher than that of the nitrate ternary system with the same cations [32] Besides
because of the thermal decomposition issue the choice of component involved in the multi-
component carbonate systems is limited Some salt like CaCO3 doesn‟t have stable form at high
temperature and the lack of multi-component system reduces the chance of the synthesis of low
melting point salt mixtures Even though this group of salt is not thermally stable and the
working temperature range is relatively small it is still viewed as possible candidate working at
high temperature due to its low price
Table 22 Melting point of various carbonate salt systems
Compound Melting Point (ordmC)
Li2CO3 732
Na2CO3 858
K2CO3 900
MgCO3 990
Na2CO3-K2CO3 710
Li2CO3-Na2CO3 496
Li2CO3-K2CO3 488
Li2CO3-K2CO3-Na2CO3 397
Alkali and Alkaline fluoridechloride salts are also selected as one possible choice as the
thermal energy storage fluid and the melting point examined from previous literatures are given
in table 23 [34-38] A lot of study has been done for this group of salt and the melting points
were found in the same range as the carbonate group And for the pure salt metal chloride salts
have lower melting point than metal fluoride ones
14
Table 23 Melting point of various fluoridechloride salt systems
Compound Melting Point (ordmC)
LiF 849
NaF 996
KF 858
LiCl 610
NaCl 801
KCl 771
LiF-KF 493
LiF-NaF 652
LiCl-KF 487
LiF-NaF-KF 454
LiF-NaF-KF-MgF2 449
LiF-KF-BaF2 320
LiF-KF-CsF-RbF 256
Several studies were also conducted to determine the melting point of molten hydroxide
salts and the results are shown in Table24 The data of pure salts and multi-component mixtures
merely in this group were not much determined in the literatures Generally they are mixed with
other groups of anion and form some low melting point salt mixtures [39-42] On the basis of the
previous literature data alkali hydroxide salts and their mixture with salts in other groups have
relatively lower melting point compared with pure carbonate and fluoride chloride group salt
mixtures Most of the melting points given in Table 4 are lower than 300oC sodium potassium
hydroxide binary mixture even reaches the melting point below 200oC Accordingly relatively
large temperature range can be obtained by using hydroxide salt mixtures or adding them as
additive
15
Table 24 Melting point of various hydroixde salt systems
Compound Melting Point (ordmC)
LiOH-LiF 427
NaOH-KOH 170
LiOH-NaOH 213
NaOH-NaNO2 232
NaOH-NaNO3 237
NaOH-NaCl-NaNO3 242
NaOH-NaCl-Na2CO3 282
22 Density
For the solar energy storage system density for the thermal energy storage fluid is also
essential parameter The density is needed for the size calculation as function of temperature and
assessing for the thermal stability of thermoclines Besides density as function of temperature is
used to evaluate the volume change in the process of freezing which contributes to potential
stress
Alkalialkaline nitrate salts were studied very much about their density as function of
temperature All the results indicate that the density was decreased linearly as temperature
increases and any specific density value in the molten state can be expressed by equation as
equation 4
= A-BT [4]
Where (gcm3) is the density of salt A (gcm
3) is the initial density value at 0
oC and B
(mgcm3degC) is the density change slope as function of temperature The coefficients are shown in
16
Table 25 for the nitrate group molten salts Among these systems pure sodium nitrate has the
largest value which reveals the high initial density value at low temperature [43] Conversely
lithium nitrate has the lowest value while it presents the smallest decrease trend as temperature
increases [44] The densities and A B values of multi-component nitrate salts were included in
the range of those two salts discussed above
Table 25 Density coefficients A and B of nitrate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiNO3 1922 0556
NaNO3 2334 0767
KNO3 2127 0760
NaNO3-KNO3 2134 0773
KNO3-CaNO3-LiNO3 2172 0735
LiNO3-KNO3-NaNO3 2083 0715
Several experiments were also conducted to measure the density as function of temperature
for the individual and multi-component carbonate salt systems The density of the carbonate salt
also follow the same trend as that of nitrate salt and the temperature dependence of density
followed the linear equation as discussed above It is observed that all the carbonate salts have
higher initial density coefficient A than the nitrate salt The largest value is reached to 2511 and
even the lowest value in this group is greater than the maximum A of nitrate group [45-49]
What‟s more the regression slope coefficient B of carbonate salt is lower compared to that of the
nitrate salt group Accordingly the salts in this group present larger density in the molten state
and the density coefficient A and B are given in Table 26
17
Table 26 Density coefficients A and B of carbonate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
Li2CO3 2303 0532
Na2CO3 2350 0448
Na2CO3-K2CO3 2473 0483
Li2CO3-K2CO3 2511 0599
Li2CO3-Na2CO3 2456 0519
Li2CO3-Na2CO3-K2CO3 2364 0544
Density of metal fluoride and chloride molten salt were also examined and present similar
regression trend as temperature increases The linear temperature dependence is also expressed
by the same equation On the basis of previous literature data the pure chloride salt shows lower
density than the fluoride salt with the same cation in the molten state [49] What‟s more the
sodium halide salt has the largest density value while the lithium halide salt has the lowest value
which is very similar to the nitrate group salt The density determination coefficient A and B are
given in Table27
Table 27 Density coefficients A and B of chloridefluoride salts
Compound A(gcm3) Btimes103(gcm
3degC)
LiCl 1766 0432
NaCl 1991 0543
KCl 1976 0583
LiF 2226 0490
NaF 2581 0636
KF 2469 0651
LiF-NaF 2520 0818
LiCl-NaF-KCl 2436 0742
LiF-NaF-MgF 2240 0701
18
The density measurement of hydroxide was not conducted as much as those three anion
groups discussed above Only few data of density is available for the alkali hydroxide salt when
added into other salt systems and temperature dependence also follows the linear regression
trend [32 41] The density determination coefficient A and B are given in Table 28
Table 28 Density coefficients A and B of molten salt mixture with hydroxide salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiCl-LiOH 16 0443
LiF-LiOH 165 0471
23 Heat capacity
In the heating process the temperature of solar energy storage molten salt is increase by
absorbing energy from the solar radiation Conversely the same amount of heat is released and
applied to heating system in the process of cooling Heat capacity is the amount of heat required
to increase the temperature of certain material by 1 oC and can be viewed as the directly relevant
parameter to the energy storage ability To some extent the large heat capacity assures the
efficiency of the application of solar energy storage materials
The heat capacity of alkalialkaline nitrate salt was investigated for both individual and
multi-component system in the previous literature To simplify the comparison only the heat
capacity value at 500oC is shown in all the following tables In the liquid state the heat capacity
increases with temperature following linear equation and the increasing slope is as small as 10-5
to 10-4
[50 51] Among those alkali nitrate salt systems lithium nitrate has the largest heat
19
capacity at 500oC while potassium nitrate presents the lowest value at that temperature In table
29 the heat capacity results at the selected temperature in literature are given
Table 29 Heat capacity of alkali nitrate salt at 500oC
Compound Heat capacity(JgK)
LiNO3 2175
NaNO3 1686
KNO3 1400
NaNO3-KNO3 1533
LiNO3-KNO3 1642
LiNO3-KNO3-NaNO3 1681
For the carbonate salt systems in the molten state the heat capacity is almost constant and
almost independent with temperature [32 33] Same as the nitrate group salts the heat capacity
for pure carbonate salt decreases as the atomic number of the alkali element increases which
means the value for lithium carbonate is the largest and that of potassium carbonate is the
smallest Generally the heat capacity value for carbonate in molten state is larger than that in
solid state However the sodium-potassium carbonate binary system is an exception for which
the heat capacity in solid state is larger than liquid state In table 210 the heat capacity results of
carbonate salts at the selected temperature in literature are given
Table 210 Heat capacity of alkali carbonate salt at 500oC
Compound Heat Capacity(JgK)
Li2CO3 250
Na2CO3 178
K2CO3 151
Na2CO3-K2CO3 157
20
Li2CO3-K2CO3 160
Li2CO3-Na2CO3 209
Li2CO3-K2CO3-Na2CO3 163
The heat capacity of fluoridechloride salt was measured in several literature and found
that for the pure salt the lithium halide has the biggest heat capacity data in the molten state
while the potassium halides shows the lowest heat capacity value Similar to the carbonate group
the heat capacity value of fluoridechloride salt varies little with temperature in the liquid state
[32 33] The values at 500oC for the alkalialkaline halides are shown in Table 211
Table 211 Heat capacity of fluoridechloride salt at 500oC
Compound Heat Capacity (JgK)
LiCl 148
NaCl 115
KCl 090
LiF-KF 163
NaCl-MgCl2 100
LiF-NaF-KF 155
KCl-MgCl2-CaCl2 092
The heat capacity of pure and multi-component hydroxide salt systems is limited in the
previous literature and the values in the liquid state follow linear equation which is observed for
all the molten salt discussed above [52] The values at 500oC for the alkalialkaline halides are
shown in Table 212
21
Table 212 Heat capacity of hydroxide salt at 500oC
Compound Heat Capacity(JgK)
NaOH 188
LiOH-NaOH 221
NaOH-KOH 182
In summary on the basis of comparison of various physic-chemical properties molten
nitrate slats have relatively low melting point excellent working temperature range reasonable
density and high heat capacity As the result of that molten nitrate salt is suitable to be applied as
the thermal energy storage fluid in the solar energy storage system
22
CHAPTER 3
OBJECTIVES
Based on review of previous literature data it is found that there are several disadvantages
such as the high melting point relatively low density value or poor heat capacity in liquid state
which limit the application of molten salt in certain groups in solar thermal energy storage
system Conversely alkalialkaline nitrate salt is considered as the suitable choice and proposed
as the thermal energy storage liquid for high temperature
Currently the used thermal energy storage liquid is NaNO3 (60mol)-KNO3 (40mol)
binary system (solar salt) which has the melting point at 221oC [30] Although the melting point
for this salt mixture is not the lowest it is still emphasized because of its low investment cost
However there are some drawbacks for this binary nitrate mixture The main disadvantage is
the high melting point In evenings or in winter the molten salt can easily freeze and block the
pipeline As a result of that some auxiliary cost should be added to overcome this problem and
the total investment will be increased
Development and synthesis of newer molten salt mixtures with freezing point lower than
those currently used for thermal energy storage applications is necessary for higher efficiency of
utilization of solar energy and getting rid of any unnecessary cost The approach to develop
lower freezing point molten salt mixtures is by the prediction of new eutectic mixtures and also
23
by the development of new nitrate compounds Besides these two most well known systems
several other mixtures were also studied Preliminary evaluation of several new molten salt flux
systems based on requirements for thermal energy storage systems mainly including freezing
point density heat capacity viscosity and thermal energy storage density The promising
candidate low melting point molten salt system should satisfy the requirements that eutectic
melting temperatures are lower than 220oC and the thermal energy storage densities are higher
than binary solar salt It is known that the melting point can be lowered by the addition of one or
more ABNO3 nitrate compounds where A and B are cations Consequently several multi-
component systems which have more constituent salts than solar salt were came up with and
studied with little fundamental data on the physic-chemical properties at the required operating
conditions available at present
In this thesis the new systems with simulated eutectic compositions were tested for their
experimental melting points heat capacities using the Differential Scanning Calorimetry (DSC)
technique which is considered to be the accurate instrument for thermodynamic data analysis
[53-59] Some significant thermodynamic properties such as heat capacity enthalpy and entropy
and Gibbs energy were calculated in the thesis to evaluate the energy change of the system in the
phase change process and the potential of being applied in the parabolic trough solar power plant
The energy density was obtained by using the experimental measured density and heat capacity
of the mixtures in molten state Finally 9 down-selected systems were present and discussed
24
CHAPTER 4
THERMODYNAMIC MODELING OF SALT SYSTEMS
41 Thermodynamic modeling
To lower the melting point of solar energy storage system multi-component system is
applicable Thermodynamic model was introduced to predict the eutectic temperature of salt
systems based on the Gibbs energies of fusion of individual salt and that of mixing of constituent
binary systems At the eutectic temperature the Gibbs energies in the liquid state and solid state
of salt are equal In thermodynamics Gibbs energy of fusion can be expressed by the equation
given as follows
G = H-TS [5]
Where H is the change of enthalpy of fusion and S is the change of entropy of fusion Equally
the entropy change of fusion can be expressed by differentiating G and the equation is given
[6]
It is known that the change in entropy can be expressed in terms of change in heat capacity in the
melting process as
[7]
25
If the change of heat capacity is assume to be independent of temperature the integral of
from Tm to T can be shown as
[8]
where Sm is the entropy of fusion at the melting point which is equal to Accordingly
Eq8 can be rewritten as
[9]
Substituting Eq 9 in Eq 6 and integrating the equation from Tm to T we get
[10]
Eq 10 illustrates that by using the change of heat capacity melting point and enthalpy of fusion
the Gibbs energy change at any temperature can be obtained
The standard Gibbs energy of fusion of a salt bdquo1‟ can be expressed in terms of the activity
of the salt as
[11]
where is the molar excess Gibbs energy and X1 is the molefraction of the salt bdquo1‟ Gibbs
energy of fusion at any give temperature T is expressed by Eq 7 in terms of its molefraction and
partial molar excess Gibbs energy
26
Take LiNO3-NaNO3-KNO3 as an example in which the integral molar excess Gibbs energy is
composed of the summation of the Gibbs energies of three constituent binary system and one
ternary The expression of the integral excess Gibbs energy is given by Eq12
[12]
Gibbs energies of the three constituent binary systems LiNO3-NaNO3 LiNO3-KNO3 and
NaNO3-KNO3 of the LiNO3-NaNO3-KNO3 ternary system are taken from the literature [48 49]
The Gibbs energies of mixing or the integral excess Gibbs energies of the three constituent
binary systems of the LiNO3-NaNO3-KNO3 ternary system are given below
LiNO3-NaNO3 Binary System
Jmol [13]
LiNO3-KNO3 Binary System
Jmol [14]
NaNO3-KNO3 Binary System
Jmol [15]
When assume the intergral excess Gibbs energy of to be zero the excess Gibbs energy in
the ternary system can be expressed by the summation of three constituent binary systems
[16]
27
Generally the partial molar excess Gibbs energies are reduced from the integral molar
excess Gibbs energy and can be expressed by the generalized equation for certain ldquomrdquo
component salt as
[17]
In the ternary system the i value equals to 12 and 3 and the partial molar excess Gibbs energy
of mixing for each component can be expressed as follows
[18]
[19]
[20]
Based on Eq 7 and the partial molar excess Gibbs energy of individual component the
Gibbs energy in the fusion can be expressed as Eq21- 23
[21]
[22]
[23]
42 Calculations
The fusion of the ternary salt system is defined by solutions of Eq 21-Eq 23 Newton-
Raphson method can be used to solve these three non-linear equations by linearizing the non-
linear equations using the Taylor series and truncating the series to first order derivatives
28
Consider the three non-linear functions F G and H in three variables x y and z The three
equations that are solved for the three variables are written as
F(x y z) = 0
G(x y z) = 0
H(x y z) = 0 [24]
The partial derivatives of the function F with respect to x y and z are given as
[25]
Similarly the partials derivatives can be expressed for the other two functions G and H
Newton-Raphson iterative method of solving the three equations in three variables
essentially deals with the solution of the incremental vector in the matrix equation given below
[26]
For the initial values of x y and z (say xi yi and zi) the right hand side vector contains the
values of the functions at the initial values (xi yi and zi) The 3times3 matrix on the left hand side
contains the partial derivatives of the functions with respect to the three variables at the initial
values Solutions of the matrix equation (Eq 26) result in the increments of the variables x y
and z The variables for the next iteration will then be xi + x yi + y and zi + z The
process of solving the matrix equation (Eq 26) is continued until the increments in the variables
x y and z is less than a very small quantity The iteration process is then said to be
29
converged and the values of the variables at convergence of the solution are the roots of the
system of the three fusion equations
The composition of LiNO3 NaNO3 and KNO3 and the eutectic temperature is solved by
using the Newton-Raphson iterative method Different from the data in previous literature the
eutectic temperature for the ternary is 116oC Besides the composition for each component is
also different from those published in literatures The new molten ternary system is composed of
2592 wt LiNO3 2001 wt NaNO3 and 5407 wt KNO3 The similar method is also applied
to other multi-component systems to determine the composition and eutectic temperature The
predicted melting points for new solar energy storage system are given Table41
Table 41 Calculated composition and melting point of multi-component molten salts systems
System Composition (wt) Calc Tmp
LiNO3 NaNO3 KNO3 NaNO2 KNO2 Mg(NO3)2 MgKN (degC)
Salt 1 259 20 541 - - - - 116
Salt 2 - 161 547 292 - - - 1238
Salt 3 175 142 505 178 - - - 986
Salt 4 115 104 274 - - - 507 986
Salt 5 172 139 476 172 41 - - 957
Salt 6 9 423 336 - 151 - - 1000
Salt 7 193 - 546 237 24 - - 1081
Salt 8 193 - 559 239 - 09 - 1008
Salt 9 154 172 324 - - 83 267 1036
30
CHAPTER 5
EXPERIMENTAL PROCEDURE
51 Melting point determination of molten salt mixtures
511 Materials
Ternary quaternary and quinary nirate and nitrite mixtures were tested in the thesis Most
components in the mixtures don‟t require any pre-preparation and can be used as received The
only exception is new developed MgKN which was composed of 6667 mol KNO3 and 3333
mol Mg(NO3)2 This unique compound is synthesized from magnesium nitrate hexahydrate
(98 Alfa Aesar) and potassium nitrate (ACS 990 min Alfa Aesar) and added into the
mixture as one single component As received magnesium nitrate hexahydrate is dehydrated
before synthesizing MgKN compound Weighted amount of magnesium nitrate taken in a
stainless steel crucible and placed on a hot plate in an argon atmosphere Temperature of the salt
is measured with a thermocouple immersed in the salt The temperature was held at 52315 K for
2 hours The salt solidifies to a white mass The temperature of the salt is then raised to 57315 K
slowly to remove any traces of moisture and to ensure complete dehydration The complete
removal of water is ascertained by weight loss
512 Apparatus and Procedure
31
Differential scanning calorimetry (DSC) analysis was performed using Perkin Elmer
Diamond DSC instrument and the setup is shown in fig 51 Heat flow and temperature can be
recorded in the instrument with an accuracy of 00001 mW and 001 K respectively The
measurements were made under purified nitrogen atmosphere with a flow rate of 20ccmin and at
a heating rate of 5 Kmin
Fig 51 Photography of set-up for DSC equipment
After dehydration if necessary each component was weighed to an accuracy of 01mg with
the electrical balance and mixed thoroughly in a stainless steel crucible Later the mixture is
heated up to certain temperature at which the entire salt melts At this temperature the salt
mixture was held for about 30 minutes The salt mixture is allowed to air cool to ambient
temperature This procedure is repeated 3 to 4 times to get the well-mixed compound Standard
aluminum pan with lid used for DSC measurements are weighed before the experiment Small
amount of the synthesized compound is placed carefully in the aluminum pan and closed with
the lid The lid is crimped by a sample press and the pan is weighed The weight of the sample is
32
determined by removing the weight of the pan and lid For the determination of melting point
and heat capacity (20-25) mg of the sample was used
Perkin-Elmer Diamond Differential Scanning Calorimeter (DSC) is used to measure the
melting point and heat capacity of compound The crimped ample pan was immediately put
inside the sample chamber of DSC after preparation and held at 52315 K for 10 hours to remove
the trace amount of moisture possibly caught in the process of loading sample and also to ensure
a homogeneous mixture In the experimental procedure a temperature range from 29815 K to
52315 K was set with a heating rate of 5 K min
1 followed by a cooling cycle at the same rate
This cycle is repeated for at least 6 times to ensure good mixture of the sample and
reproducibility of the results
52 Heat Capacity determination of molten salt mixtures
To start Cp measurement the same procedure as that of melting point determination is
followed with an addition of bdquoiso-scan-iso‟ steps to the program after 5-cycle temperature scan
Starting from 29815 K the temperature was held for 5 minutes before and after each scan step
Small temperature scan range is chosen to avoid thermal resistance between device and testing
sample except when the temperature is approaching the melting temperature The upper limit for
the Cp measurement was set to 62315 K in our experiments Since the change in the molar heat
capacity of the salt in the liquid state is very small the Cp data in the liquid state can be easily fit
to an equation and extrapolated to higher temperatures To get the value of molar heat capacity
of the sample heat flow curve for the baseline of the empty sample pan also needs to be obtained
immediately following the identical ldquoiso-scan-isordquo steps which were used for the actual sample
33
run The difference of heat flow between the actual crimpled sample and the empty sample pan is
the absolute heat absorbed by the test sample
53 Density determination of molten salt mixtures
Density measurement was carried out with standard densitometer which has fixed volume
Initial weight of the densitometer is measured and noted Salt composition of which the density
is measured is placed in a beaker on a hot place The densitometer is also placed on the same hot
plate The temperature is set to a fixed value above the melting point of the salt and is measured
by a thermocouple After the salt is melted and when the temperature shows stable reading the
molten salt is poured in to the densitometer up to the set mark on the sensitometer bottle The
weight of the densitometer with the molten salt is measured The weight difference between this
weight and the weight of empty densitometer gives the weight of the molten salt at the fixed set
temperature By knowing the fixed volume in the densitometer the density of the salt at that
temperature can be calculated This procedure is repeated at least three times to accurately
determine the density of the salt
34
CHAPTER 6
RESULT AND DISCUSSION
61 Melting point determination
611 DSC equipment calibration
Before the actual melting point measurement pure indium zinc metal and several
individual salts were used to calibrate the DSC equipment For metals only one sharp peak was
observed for each and the heat flow curve for indium metal is shown in fig 61 However larger
and boarder peaks are found for salts just like the condition illustrated in fig 62 for pure
potassium nitrate Based on the results shown in Table 61 the experimental data for melting
points and enthalpies of fusion have excellent agreement with the literature values [60-63] The
variation of point is within 07 and the variation of change of enthalpy is less than 3
Figure 61 Melting point calibration with indium sample
35
Figure 62 Melting point calibration with KNO3 sample
Table 61 Calibration data of melting points with different samples
Sample
Lit
Tmp
Expt
Tmp
Lit
Ttrans
Expt
Ttrans
Lit
ΔHfusion
Expt
ΔHfusion
Lit
ΔHtrans
Expt
ΔHtrans
degC degC degC degC Jg Jg Jg Jg
Indium 1566 1563 - - 286 278 - -
Zinc 4195 4188 - - 1086 1068 - -
LiNO3 2567 2550 - - 3617 3633 - -
NaNO3 3100 3081 2770 2753 1777 1756 147 152
KNO3 3370 3372 1330 1332 993 1005 538 529
612 Results
Differential scanning calorimetry (DSC) was used to determine the melting point and any
solid state phase transitions of the salt mixture A low scanning rate was chosen to record the
heat flow curve as function of temperature in order to improve the sensitivity of detection [64] It
helps to pick up any small endothermic peaks and also avoids the thermal resistance between the
36
internal furnace and sample Nine systems were chosen to test and the eutectic composition is
already listed in Table 41
All the selected systems are composed of alkaline nitrate and nitrite and most of them have
three basic components which are lithium sodium potassium nitrate or nitrite All the quaternary
and quinary systems were developed on the basis of the LiNO3-NaNO3-KNO3 baseline ternary
Figure 63-611 shows the DSC plot of all the salt systems DSC plots for each system were
collected for at least five runs (each run with fresh salt preparation) to ensure the reproducibility
All the onset temperatures peak temperatures predicted temperatures enthalpy of fusion for
melting peaks and the solid phase transformation temperatures are given in Table62
Figure 63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt
37
Figure 64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt
Figure 65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt
38
Figure 66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt
Figure 67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt
39
Figure 68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
Figure 69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
40
Figure 610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt
Figure 611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN salt
Table 62 illustrates that the predicted melting point is close to the experimental
determined value and most deviation is within 10 except for system 9 The great agreement
41
between experimental and calculated data verifies the accuracy and feasibility of the
thermodynamic modeling
Table 62 DSC results of melting point transition point and predicted melting point
System Tmp Ttrans ΔHfusion
Calculated degC Onset degC Peak degC Peak degC Jg
Salt 1 1160 994 1191 1043 600
Salt 2 1238 1150 1240 NA 97
Salt 3 986 940 999 NA 244
Salt 4 986 940 1010 NA 60
Salt 5 957 910 950 NA 62
Salt 6 1000 930 960 NA 86
Salt 7 1081 992 1003 793 60
Salt 8 1008 1010 1019 853 59
Salt 9 1036 834 892 NA 93
613 Discussion
It is observed that the first curve is different from last ones shown in the DSC plots and
this phenomenon is common for all the melting point measurement with DSC technique This
happened because in the first cycle the moisture caught by salt mixture especially the lithium
nitrate was removed in the process of heating Moreover the partially solidified sample in the
sample loading process can be re-homogenized in the first heating cycle [65-67] In figure 63
69 and 610 more than one endothermic peak was found The first smaller endothermic peak
refers to solid state phase transition of the salt mixture The second larger endothermic peak
refers to the melting of the salt Normally the onset temperature of transition is taken as the
experimental transition point for any metallic sample However in case of molten salts mixtures
since the thermal conductivity is low [68-74] the complete transition is ensured only at the peak
42
transition temperature The thermal gradient which exists due to the low thermal conductivity of
the salt results in internal heat flow which enhances the mixing in the salt Thus the transition
temperature is defined as the peak temperature of phase transition For salt No1 the small
endothermic peak happened before and was connected to the main peak which occurred at
39027K The first endothermic peaks for salt No 7 and 8 occurred at almost the same
temperature because of the similar composition for these two compounds Since the small
amount of magnesium nitrate and potassium nitrite contained in these two compounds the small
endothermic peak can hardly be related to these two components Obviously the rest three major
components must have something to do with the first peaks happened before the melting peaks
for both cases Each component among the major three ones were tested to find out any possible
solid phase transition peaks of them and the results shown in Table 63 which reveals that
lithium nitrate doesnt have any phase transition peak in solid state while potassium nitrate and
sodium nitrite both own the solid phase transformation peaks before their melting peaks
Table 63 Fusion and solid phase transition temperature for individual salts
System Tmp degC Ttrans degC ΔHfusion Jg ΔHtrans Jg
LiNO3 2550 - 3633 -
KNO3 3372 1332 1005 529
NaNO2 4311 4170 1119 880
The further investigation was carried out by running the KNO3-NaNO2 (550 wt and 238 wt )
binary compound with the very similar weight percentage as that in salt No 7 (546 wt and
237 wt) and salt No 8 (559wt and 239wt) By converting the weight percentage of the
studied binary system into 100 scale the weight fraction for sodium nitrate and potassium
nitrate can be rewritten as 698wt and 302wt The DSC plot for this binary system was
43
shown in fig 612 Although the solid transition and melting temperature were brought down by
adding lithium nitrate the shape of the plots in fig 69 and 610 are identical to that shown in fig
612 The enthalpy of solid state transformation of the binary salt was also converted to that in
both quaternary systems by using the weight fraction occupied by the binary system and the
comparable change of converted enthalpy between the binary system and two quaternary systems
indicates the relevance of the solid transition peaks in salt 7 and 8 to the combined effect of
potassium nitrate and sodium nitrite
Figure 612 DSC plot of 698wt KNO3- 302wt NaNO2 binary system
The similar analysis was applied to No1 salt to find out the reason for the presence of a
small peak adherent to the main melting peak before the melting point Sodium nitrate and
potassium nitrate binary system was synthesized based on the weight fraction of these two
constituent salts in No 1 salt DSC plot for the sodium nitrate-potassium nitrate binary system in
Fig 613 with the converted composition which is essentially same as that in the No1 ternary
system shows smooth heat flow curve before the melting peak which means the solid transition
peak in ternary is not simply relative to the binary system Assumption was made that the solid
44
phase transformation peak in the ternary salt is resulted from a multiple effect ie the
combination of one of the eutectic binary system involved in the ternary salt mixture and the
other binary system which is composed of the rest components The statement is verified that the
small peak in salt 1 is mainly caused by the solid phase transformation peak in lithium nitrate-
potassium nitrate eutectic binary system given the similar shape of the DSC plots in Fig 614
Since in salt No1 there is excess amount of sodium nitrate to form the lithium nitrate-sodium
nitrate binary system the rest sodium nitrate can interact with potassium nitrate and form new
sodium-potassium nitrate system which is shown in fig615 Besides a solid phase
transformation peak is observed in fig615 which has a very small area and won‟t change the
shape of phase transformation peak in fig614 when these two binary systems are combined and
form salt 1 The enthalpies of solid state transformation in two binary salts were also converted
to that in salt 1 by using the weight fractions occupied by both binary systems The difference
of the change of converted enthalpies between the lithium-potassium nitrate eutectic binary and
ternary system is filled by the binary mixture which is composed of the rest components sodium
nitrate-potassium nitrate The comparable converted values of enthalpy change between salt 1
and its two constituent binary systems further verify the assumption that the solid phase
transformation happened in salt 1 is mainly due to the combined effect of LiNO3-KNO3 eutectic
binary system and NaNO3-KNO3 binary system
45
Figure613 DSC plot of 270wt NaNO3-730wt KNO3 binary system
Figure614 DSC plot of 458wtLiNO3-542wtKNO3 binary system
46
Figure615 DSC plot of 460wt NaNO3-540wt KNO3 binary system
Unlike those discussed mixtures above salt No2 Salt No4 Salt No5 and Salt No6 have
only one relatively board melting peak and the heat flow curve before and after are very stable
Similarly there is no solid transformation peaks observed in salt No3 salt No7 and salt No8
However the heat flow after the melting peak in these cases are not stable and the main
endothermic peak is followed by a small hump which is considered to be the recrystallization
process once the compound entered into the liquid state When the process is finished the heat
flow curve returns to steady state
Heating rate is a significant parameter when collect the heat flow curves by using DSC
technique Fig 616(a) and Fig 616(b) illustrate the difference of melting point for salt No6 due
to the change of heating rate If the heating rate is 20oCmin the peak temperature and onset
temperature for the melting peak is 9669oC and 9221
oC respectively Once the heating rate is
decreased to 5oCmin these two temperatures will also be lowered to 9614
oC and 9190
oC The
difference is resulted from the diverse amount of thermal resistance between the testing sample
and the furnace inside the DSC instrument [75] Under higher heating rate the decisive thermal
47
resistance is raised due to the low thermal conductivity medium between the furnace and the
actual sample The insensitivity of gas heat conduction medium in DSC results each unit of
temperature increase on one side cannot have an immediate response on the other side of the gas
Consequently the sample holder which is connected the furnace has a higher temperature than
that inside the sample In this condition the value of temperature profile collected as the sample
holder temperature is larger than the actual temperature The deviation will be much smaller
when the heating rate is reduced In the case the thermal resistance will be decreased because of
the lower temperature gradient of the gas medium in the heating process As a result of that the
collected temperature from the sensor attached to the sample holder will be very close to the
actual temperature inside the testing sample
Figure 616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 20oCmin
heating rate
48
Figure 616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 5oCmin
heating rate
Besides the difference of temperature while using higher and lower heat rate the solution
of DSC will also be affected by different heating rate Fig 617(a) shows the DSC plot for salt
No 7 using the heating rate as 5oCmin and the DSC plot in Fig 617(b) is collected under the
heating rate as 20oCmin It can be observed that in the lower heating rate two small separated
peaks can be viewed as two parts of the solid phase transformation process while in Fig 617(b)
two small peaks before the melting peak merge and present as a board hump The qualification
of resolution can be executed by the term named resolution factor RMKE which is calculated as
the ratio of the peak heat flow value of the separated peaks to that of the concave point between
two peaks The equation for determining RMIKE is given in Eq 27 [76 77]
RMIKE =hpeakhmin [27]
49
Figure 617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 5oCmin
heating rate
Figure 617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 20oCmin
heating rate
In the case of lower heating rate the RMKE is determined to be 15 and the value for higher
heating rate is not available because the concave point of heat flow doesn‟t exist from
Fig617(b) Since the higher RMKE value indicates better resolution it can be stated that the
50
lower heating rate also results in greater sensitivity of the equipment to pick up any small
endothermic peaks
Besides the down-selected 9 compounds some more salt mixtures were also tested Most
of them were not selected to the final candidate for the thermal energy storage application
because of their higher melting point Table 64 gives some of the trial systems measured with
DSC technique It is illustrated that the melting points of mixtures with lower or even no content
of lithium nitrate turn out to be higher than those with sufficient amount of lithium nitrate For
most of the mixtures with melting point lower than 120oC the amount of lithium nitrate should
be larger than 81wt Also all of the systems in table 64 with lithium nitrate less than 15wt
have melting point higher than 140oC Based on the observation above it is concluded that the
lithium nitrate can be used as an additive to bring the melting point down for thermal energy
storage systems
51
Table 64 Melting points of candidate systems as function of temperatures
System Composition (wt)
Onset
Temp
Peak
Temp
(oC) (
oC)
LiNO3 ndash NaNO3 ndash KNO2 107 459 434 890 910
LiNO3 - KNO3 - NaNO2 196 564 241
1024 1046
LiNO3 - NaNO3 - KNO3 - KNO2 90 423 337 151
930 960
LiNO3 - NaNO3 - NaNO2 - KNO2 81 454 65 401
900 910
LiNO3 - KNO3 - NaNO2 - KNO2 193 546 237 24
992 1003
LiNO3 - KNO3 - NaNO2 ndash Mg(NO3)2 193 559 238 09
1010 1020
LiNO3 - NaNO3 - KNO3 - Mg(NO3)2
- MgK 154 172 324 83 267 834 892
LiNO3 - NaNO3 - KNO2 ndash Ca(NO3)2 14 390 333 263
1250 1470
NaNO3 - KNO3 - NaNO2 - KNO2 425 163 71 341
1407 1447
NaNO3 - KNO3 - KNO2 ndash Mg(NO3)2 432 146 380 42
1386 1421
NaNO3 - NaNO2 - KNO2 - Ca(NO3)2 451 92 410 48
1150 1390
LiNO3 - NaNO3 - NaNO2 - KNO2 -
Ca(NO3)2 15 393 37 323 232 1380 1480
LiNO3 - NaNO3 - KNO2 - Ca(NO3)2 -
Mg(NO3)2 14 379 313 275 20 1339 1534
62 Heat capacity determination
621 Heat capacity calibration
DSC was also calibrated for the heat capacity measurement Lithium nitrate sodium
nitrate and potassium nitrate were examined for the heat capacities from room temperature to
upper limit temperature for the instrument In liquid state the heat capacity values for each salt
can be fit to straight line with trace amount of increasing trend Since the temperature range from
the onset temperature of liquid state to the upper limit of DSC is relatively small the heat
capacity values for pure individual salts can be viewed as constants The comparison between the
theoretical and experimental heat capacity data is given in Table 65 Except lithium nitrate the
52
experimental heat capacities data for the rest two systems are almost same as the literature Even
for lithium nitrate which demonstrates the biggest difference from the literature data the 28
vibration is still within a reasonable range
Table 65 Calibration data of heat capacities with different samples
Sample Lit Cp Expt Cp
JgK JgK
LiNO3 218 212
NaNO3 169 167
KNO3 140 139
622 Results
The materials used in the heat capacity measurements are the same as those in the melting
point experiments Molar heat capacities of the all compound were measured by the DSC
equipment from room temperature to 62315 K The heat flow is recorded as a function of
temperature in ldquoiso-scan-isordquo steps at intervals of 20 K The bdquoiso stage‟ refers to isothermal
holding at a particular temperature bdquoscan stage‟ refers to the heat flow recording at a heating rate
of 5 K min1
up to a an increment of 25 K followed by another isothermal holding stage This is
a standard procedure followed in the measurement of heat capacity of materials using the DSC
equipment [63 64] This procedure of heat capacity measurement has two advantages (i) any
heat fluctuations during the recording are avoided by the isothermal steps and (ii) any phase
transition can be highlighted by the choice of temperature range The absolute heat flow to the
sample is determined by subtracting the heat flow collected by running a baseline curve with an
empty pan Because the heat capacity measurement in the heating process corresponds to
53
collecting the value of required heat flow at each temperature all the heat capacity plots have the
same shape with that of heat flow in the melting point measurements Take the heat capacity plot
of LiNO3-NaNO3-KNO3 ternary system as an instance which is shown in fig 618 the heat
capacity curve also has two different peaks The first little peaks corresponds to one occurs at
39027K which was observed in fig 63 the second large and sharp peak happened right after the
small one is prevalent to the endothermic peak with the peak temperature as 39027 K Similarly
after the phase transformation the heat capacity in liquid state becomes very stable and increase
with temperature linearly with little slope
Fig 618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system as function of
temperature
The heat capacity change as function of temperature for salt No1 was illustrated in fig
619 Based on the trend of heat capacity in the liquid state any value for the system in the liquid
can be extrapolated The expressions for heat capacity in liquid state for the new molten salt
systems were discussed and given in the next sectionTable66 shows the specific heat capacity
54
of the all the selective compounds measured at 62315 K and extrapolated at 77315K Besides
the molar heat capacities at 77315K are given in Table 66 of all the salts
Fig 619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K
Table 66 Heat capacity of selected new TES molten salt mixtures
System Expt (62315K) Extrapolated(77315K) Extrapolated(77315K)
Cp JgK Cp JgK Molar Cp JmolK
Salt 1 153 170 1521
Salt 2 143 168 1515
Salt 3 148 155 2183
Salt 4 153 166 1411
Salt 5 153 170 1440
Salt 6 151 163 1435
Salt 7 156 167 1443
Salt 8 155 168 1410
Salt 9 161 170 1937
55
623 Thermodynamic properties
The standard thermodynamic properties such as entropy enthalpy and Gibbs energy for
salt mixtures are determined from the experimental data of melting point and heat capacity in the
temperature range of the present study and expression for determining these properties are given
in equation 28-30 In thermodynamics all these three properties are related to heat capacity and
its variances with temperature In the studied temperature range (29815K-62315K) they can be
described as expression includes heat capacity
[28]
[29]
[30]
Where Tt is the solid transformation temperature Tmp is the melting point ΔHt is enthalpy of
solid phase transformation and ΔHfusion is enthalpy of fusion The standard thermodynamic
properties entropy enthalpy and Gibbs energies as function of temperature for each compound
are expressed in the following section
6231 LiNO3-NaNO3-KNO3 (Salt 1)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3
compound (i) solid state 1 (32315-38415) K (ii) liquid state (40315-62315) K Accordingly
56
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62311 Heat capacity of solid state 1 (29815-38415) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the solid state 1 in the
temperature range of 29815 to 38415 K is fit to a second order polynomial equation Eqn (31)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[31]
( ) K
R2 = 0982
62312 Heat capacity of liquid state (40315-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a linear equation Eqn (32) gives the linear
equation along with the least square fit parameter (R2) in the temperature range for the liquid
state of the compound
JKmol [32]
57
R2 = 0947
Heat capacity data of the LiNO3-NaNO3-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62313 Thermodynamic properties of solid state 1(29815-38415) K
JKmol [33]
Jmol [34]
[35]
Jmol
62314 Thermodynamic properties of liquid state 2(40315-62315) K
[36]
58
JKmol
Jmol [37]
[38]
Jmol
Among the equations above equation (33)-(35) refer to the thermodynamic properties for
solid state equations (36)-(38) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature ranges for solid and liquid state are
given in Table A1 and A2 in appendix A respectively with the corresponding heat capacity as
function of temperature
6232 NaNO3-NaNO2-KNO3 (Salt 2)
The heat capacity data can be divided into two sections for NaNO3-NaNO2-KNO3
compound (i) solid state 1 (32315-39215) K (ii) liquid state (41315-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62321 Heat capacity of solid state 1 (29815-39215) K
59
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the solid state in the
temperature range of 29815 to 39215 K is fit to a second order polynomial equation Eqn (39)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[39]
( ) K
R2 = 0978
62322 Heat capacity of liquid state (40315-62315) K
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a second order polynomial equation Eqn (40)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[40]
R2 = 0941
60
Heat capacity data of the NaNO3-NaNO2-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62323 Thermodynamic properties of solid state 1(29815-39215) K
JKmol [41]
Jmol [42]
[43]
Jmol
62324 Thermodynamic properties of liquid state 2(40315-62315) K
JKmol [44]
61
Jmol [45]
[46]
Jmol
Among the equations above equation (41)-(43) refer to the thermodynamic properties for
solid state equations (44)-(46) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table B1 and B2 in appendix B respectively with the corresponding heat capacity as
function of temperature
6233 LiNO3-NaNO3 -KNO3-MgK (Salt 3)
The heat capacity data can be divided into two sections for LiNO3-NaNO3 -KNO3-MgK
compound (i) solid state 1 (29815-36415) K (ii) liquid state (42115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62331 Heat capacity of solid state 1 (29815-36415) K
62
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the solid state in the
temperature range of 29815 to 36415 K is fit to a second order polynomial equation Eqn (47)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[47]
( ) K
R2 = 0995
62332 Heat capacity of liquid state (42115-62315) K
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the liquid state in the
temperature range of 42115 to 62315 K is fit to a second order polynomial equation Eqn (48)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[48]
R2 = 0963
63
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
62333 Thermodynamic properties of solid state 1(29815-36415) K
JKmol [49]
Jmol [50]
[51]
Jmol
62334 Thermodynamic properties of liquid state 2(42115-62315) K
64
JKmol [52]
Jmol [53]
[54] [29]
Jmol
Among the equations above equation (49)-(51) refer to the thermodynamic properties for
solid state equations (52)-(54) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table C1and C2 in appendix C respectively with the corresponding heat capacity as
function of temperature
6234 LiNO3-NaNO3-KNO3-NaNO2 (Salt 4)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-NaNO2
compound (i) solid state 1 (29815-36315) K (ii) liquid state (38115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62341 Heat capacity of solid state 1 (29815-36315) K
65
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the solid state in the
temperature range of 29815 to 36315 K is fit to a second order polynomial equation Eqn (55)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[55]
( ) K
R2 = 0995
62342 Heat capacity of liquid state (38115-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the liquid state in the
temperature range of 38115 to 62315 K is fit to a second order polynomial equation Eqn (56)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[56]
R2 = 0972
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
66
62343 Thermodynamic properties of solid state 1(29815-36315) K
JKmol [57]
Jmol [58]
[59]
Jmol
62344 Thermodynamic properties of liquid state 2(38115-62315) K
JKmol [60]
Jmol [61]
67
[37]
Jmol [62]
Among the equations above equation (57)-(59) refer to the thermodynamic properties for
solid state equations (60)-(62) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table D1 and D2 in appendix D respectively with the corresponding heat capacity as
function of temperature
6235 LiNO3-NaNO3-NaNO2-KNO3-KNO2 (Salt 5)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-NaNO2-KNO3-
KNO2 compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62351 Heat capacity of solid state 1 (29815-35915) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
in the temperature range of 29815 to 35915 K is fit to a second order polynomial equation Eqn
(63) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
68
[63]
( ) K
R2 = 0996
62352 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the liquid
state in the temperature range of 37515 to 62315 K is fit to a second order polynomial equation
Eqn (64) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[64]
R2 = 0969
Heat capacity data of the LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62353 Thermodynamic properties of Solid state 1(29815-35915) K
JKmol [65]
69
Jmol [66]
[67]
Jmol
62354 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [68]
Jmol [69]
[45]
Jmol [70]
70
Among the equations above equation (65)-(67) refer to the thermodynamic properties for
solid state equations (68)-(70) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table E1 and E2 in appendix E respectively with the corresponding heat capacity as
function of temperature
6236 LiNO3-NaNO3-KNO3-KNO2 (Salt 6)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-KNO2
compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62361 Heat capacity of solid state 1 (29815-36515) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the solid state in the
temperature range of 29815 to 36515 K is fit to a second order polynomial equation Eqn (71)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[71]
( ) K
R2 = 0998
71
62362 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the liquid state in the
temperature range of 37515 to 62315 K is given in Table 20 The data is fit to a second order
polynomial equation Eqn (72) gives the linear equation along with the least square fit parameter
(R2) in the temperature range for the liquid state of the compound
[72]
R2 = 0953
Heat capacity data of the LiNO3-NaNO3-KNO3-KNO2 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62363 Thermodynamic properties of solid state 1(29815-35915) K
JKmol [73]
Jmol [74]
72
[75]
Jmol
62364 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [76]
Jmol [77]
Jmol [78]
Among the equations above equation (73)-(75) refer to the thermodynamic properties for
solid state equations (76)-(78) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
73
given in Table F1 and F2 in appendix F respectively with the corresponding heat capacity as
function of temperature
6237 LiNO3-KNO3-NaNO2-KNO2 (Salt 7)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62371 Heat capacity of solid state 1 (29815-35415) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 1 in
the temperature range of 29815 to 35415 K is fit to a second order polynomial equation Eqn
(79) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[79]
(29815-35415) K
R2 = 0993
62372 Heat capacity of solid state 2 (36215-37315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 2 in
the temperature range of 36215 to 37315 K is fit to a second order polynomial equation Eqn
74
(80) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 2 of the compound
[80]
R2 = 0977
62373 Heat capacity of liquid state (37915-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the liquid state in the
temperature range of 37915 to 62315 K is fit to a linear equation Eqn (81) gives the
polynomial equation along with the least square fit parameter (R2) in the temperature range for
the liquid state of the compound
[81]
R2 = 0961
Heat capacity data of the LiNO3-KNO3-NaNO2-KNO2 compound in the two solid states
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62374 Thermodynamic properties of solid state 1(29815-35415) K
75
JKmol [82]
Jmol [83]
[84]
Jmol
62375 Thermodynamic properties of solid state 2(36215-37315) K
JKmol [85]
Jmol [86]
76
[87] [62]
Jmol
62376 Thermodynamic properties of liquid state (37915-62315) K
JKmol [88]
Jmol [89]
Jmol [90]
Among the equations above equation (82)-(84) refer to the thermodynamic properties for
solid 1 equation (85)-(87) refer to the thermodynamic properties for solid 2 equations (88)-(90)
refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy values
77
in the studied temperature range for solid 1 solid 2 and liquid state are given in Table G1-G3 in
appendix G respectively with the corresponding heat capacity as function of temperature
6238 LiNO3-KNO3-NaNO2-Mg(NO3)2 (salt 8)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62381 Heat capacity of solid state 1 (29815-33715) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid
state 1 in the temperature range of 29815 to 33715 K is fit to a second order polynomial
equation Eqn (91) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the solid state 1 of the compound
[91]
(29815-33715) K
R2 = 0994
62382 Heat capacity of solid state 2 (36115-36415) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid state 2
in the temperature range of 36115 to 36415 K is given in Table 4 The data is fit to a second
78
order polynomial equation Eqn (92) gives the polynomial equation along with the least square
fit parameter (R2) in the temperature range for the solid state 2 of the compound
[92]
R2 = 0992
62383 Heat capacity of liquid state (41115-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the liquid state in
the temperature range of 41115 to 62315 K is given in Table 5 The data is fit to a linear
equation Eqn (93) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the liquid state of the compound
[93]
R2 = 0934
Heat capacity data of the LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the two solid
states follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62384 Solid state 1(29815-35415) K
79
JKmol [94]
Jmol [95]
[96]
Jmol
62385 Solid state 2(36115-36415) K
JKmol [97]
80
Jmol [98]
[99] [74]
Jmol
62386 Liquid state (41115-62315) K
JKmol [100]
Jmol [101]
Jmol [102]
Among the equations above equation (94)-(96) refer to the thermodynamic properties for
solid 1 equation (97)-(99) refer to the thermodynamic properties for solid 2 equations (100)-
(102) refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy
81
values in the studied temperature range for solid 1 solid 2 and liquid state are given in Table H1
and H2 in appendix H respectively with the corresponding heat capacity as function of
temperature
6239 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK(Salt 9)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-
Mg(NO3)2-MgK compound (i) solid state 1 (29815-35315) K (ii) liquid state (39115-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62391 Heat capacity of solid state 1 (29815-35315) K
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state in the temperature range of 29815 to 35315 K is fit to a second order polynomial equation
Eqn (103) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[103]
( ) K
R2 = 0996
62392 Heat capacity of liquid state (39115-62315) K
82
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the liquid
state in the temperature range of 39115 to 62315 K is fit to a second order polynomial equation
Eqn (104) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[104]
R2 = 0951
Heat capacity data of the LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62393 Solid state 1(29815-35315) K
JKmol [105]
Jmol [106]
83
[107]
Jmol
62394 Liquid state 2(39115-62315) K
JKmol [108]
Jmol [109]
[110]
Jmol
Among the equations above equation (105)-(107) refer to the thermodynamic properties
for solid state equations (108)-(110) refer to thermodynamic properties of the liquid The
entropy enthalpy and Gibbs energy values in the studied temperature range for solid and liquid
state are given in Table I1 and I2 in appendix I respectively with the corresponding heat
capacity as function of temperature
84
624 Discussion of Gibbs energy change for molten salts
The Gibbs energy change data as function of temperature for 9 systems are given in fig
620 and the values at 62315K are shown in Table 67 Every system demonstrates continuous
curve throughout the whole studied temperature range Most of systems have similar Gibbs
energy change values for each temperature spot due to the comparable compositions and
properties of constituent salts However salt 3 and salt 9 Both of these salts have certain
amount of MgKN compound which presents large absolute amount of change of Gibbs energy in
the same studied temperature range [66] Since the change of Gibbs energy for multi-component
mixture is relevant to that of each constituent salt the large absolute value of ΔG of MgKN
mainly contributes to the largely negative value of salt 3 and salt 9 shown in fig 620 Besides
it is observed that most systems contain nitrite salts present lower absolute value of Gibbs energy
change For example salt 1 doesn‟t include any nitrite salt and has a relatively high absolute
value of Gibbs energy change as 1704kJmol while other systems having nitrite salts show lower
value varies from 1372kJmol to 1592kJmol
85
Fig 620 Change of Gibbs energy as function of temperature for molten salt systems
Table 67 Change of Gibbs energy values at 62315K for molten salt systems
SNo System ΔG(kJmol)
1 LiNO3-NaNO3-KNO3 1704
2 NaNO3- NaNO2- KNO3 1372
3 LiNO3- NaNO3- KNO3- MgKN 2807
4 LiNO3- NaNO3- KNO3- NaNO2 1443
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1441
6 LiNO3-NaNO3-KNO3-KNO2 1570
7 LiNO3-KNO3-NaNO2-KNO2 1592
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1583
9 LiNO3-NaNO3-KNO3-Mg(NO3)2 -MgKN 2217
86
63 Density determination
631 Density calibration
Several pure molten salts are used to calibrate the density measurement set-up before the
actual density measurement All the density values decrease as function of temperature in the
liquid state and follow the same linear equations as described in eq 4 The experimental values
at 350oC for KNO3 NaNO3 and LiNO3 are selected to compare with the literature data at the
same temperature The results are shown in Table 68 Based on the comparison of the literature
data and the experimental data the variation of density for molten nitrate salt is within in 4
Table 68 Calibration of density measurements with different pure nitrate salts
Sample Literature density Experimental density
gcm3 gcm
3
LiNO3 1727 1701
NaNO3 2066 2144
KNO3 1860 1855
632 Results and discussions
The density result of the salt as function of temperature is plotted for all the salts in Figure
621 and Figure 622 It is observed that the temperature dependence of density above the
melting point is different from that in solid state As known in solid state the density of salt has
an exponential relation with temperature while in these liquid cases the density values have
linearly dependence with temperature The stable variation as function of temperature allows the
extrapolation of density at even higher temperature The regression analysis is performed to get
the coefficient used for describing eq 4 and the results for the coefficients are shown in
87
Table69 [78-80] It is observed that the change of composition is implied on the coefficient A
which indicates the initial point at 150oC The temperature dependence coefficient B doesn‟t
change much with composition which may be mainly affected by the group of anion and cation
Table 69 Coefficient A and B for density determination of salt 1-salt 9
Salt No System A Btimes10
3
(gcm3) (gcm
3degC)
1 LiNO3-NaNO3-KNO3 2032 0493
2 NaNO3- NaNO2- KNO3 2081 0570
3 LiNO3- NaNO3- KNO3-MgKN 2055 0526
4 LiNO3- NaNO3- KNO3- NaNO2 2033 0520
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 2018 0485
6 LiNO3-NaNO3-KNO3-KNO2 2060 0554
7 LiNO3-KNO3-NaNO2-KNO2 2048 0554
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 2044 0524
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 2060 0566
Figure 621 The densities of the salt 1-salt 5 as function of temperature
88
In figure 621 all the density values are clustered around 198gcm3 at 150
oC to
186gcm3 at high temperature end and the deviation of density between all the mixtures is within
in 0047g cm3 Among all the salt mixtures the NaNO3-NaNO2-KNO3 ternary system
demonstrates the highest density value throughout the studied temperature range and LiNO3-
NaNO3-KNO3 ternary system LiNO3- NaNO3-KNO3-NaNO2 quaternary system and LiNO3-
NaNO3-KNO3-NaNO2-KNO2 quinary system show densities at the bottom side of Fig 621 For
salt 2 which doesn‟t contain any lithium nitrate the density at every selected temperature spot
is obviously higher than that of salt 1 4 and 5 which have large amount of lithium nitrate
Moreover the salt 3 which contains the relatively small amount of lithium nitrate stays in
between of salt 1 and salt 2 This comparison illustrates that the addition of lithium nitrate has
an offsetting effect on density for molten salt and it is consistent with previous literature reports
[81] The four systems presented in figure 622 also show even closer density values in the
studied temperature range Similarly salt 6 which contains the least lithium nitrate has the
largest density Salt 7 and salt 8 have almost same composition for the three dominating
components as a result of that the density curves for both mixtures are determined by the same
regression coefficient A and B Moreover the larger amount of lithium nitrate involved in these
two salt mixtures contributes to the lower density given in figure622 which further verifies the
significantly offsetting effect of lithium nitrate on density
89
Figure 622 The densities of the salt 6-salt 9 as function of temperature
The salt mixtures with maximum and minimum amount of lithium nitrate were plotted and
compared with equimolar NaNO3-KNO3 binary system and pure KNO3 salt in Fig623 [82 83]
It is observed that the NaNO3-KNO3 binary system has very similar density value to that of salt
2 because of the analogous type and composition of component in both salts The density of
pure KNO3 is slightly lower than the binary salt mixture which indicates the density of NaNO3 is
close to but higher than KNO3 in the studied temperature range Salt 1 shows the lowest density
in Fig623 due to the offsetting effect on density caused by lithium nitrate which has been
discussed above
90
Figure 623 Density of the salt 1 salt 2 as function of temperature compared to the
equimolar NaNO3-KNO3 binary system and pure KNO3
64 Thermal energy storage density of molten salts
The energy density which is considered as one of the most significant parameters of TES
application can be evaluated by calculation based on the measured density heat capacity and
working temperature range The equation of the thermal energy storage density (E) at working
temperature of 500oC is expressed in equation 111
E = Cp (500-Tm) [111]
Where Cp and are extrapolated heat capacity and density at 500oC respectively Tm is
melting point for salt mixture The extrapolation of density and heat capacity is based on the
linear temperature dependence for both parameters in molten state and the values are shown in
Table 610
91
Table 610 Extrapolated value of density and heat capacity at 500oC of salt 1-salt 9
Salt
No System
Density Heat Capacity
(gmL) (JgK)
1 LiNO3-NaNO3-KNO3 1785 170
2 NaNO3- NaNO2- KNO3 1796 168
3 LiNO3-NaNO3-KNO3-MgK 1773 155
4 LiNO3- NaNO3- KNO3- NaNO2 1792 166
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1796 170
6 LiNO3-NaNO3-KNO3-KNO2 1783 163
7 LiNO3-KNO3-NaNO2-KNO2 1771 167
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1782 168
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 1777 170
The calculated energy density for each salt is given in Table 611 compared with that of
solar salt (NaNO3-KNO3) All the new synthesized salt mixtures have significantly higher energy
density than solar salt and salt 3 shows the highest energy density among the new salts
Although salt 1 has higher heat capacity and good melting point the energy density is still the
lowest among new salt mixtures given by the effect of low density The conclusion can be drawn
from these observations that the energy density is a property affected by multiple parameters and
every part plays an important role in determining the efficiency of energy storage of salt
mixtures
92
Table 611 Energy density of salt 1-salt 9 compare to solar salt
The gravimetric storage density of new molten salts are listed in Table 612 and compared
with those different storage systems in fig 624 It is found that in the parabolic trough working
temperature range the gravimetric storage densities of new molten salts are located on the higher
side Even though some reported sensible energy storage liquids have larger gravimetric density
values than the new salts the maximum working temperatures reveal the instable working
condition at 500oC Taking conversion efficiency thermal stability and gravimetric storage
density into considerations the new molten salts are the most suitable choices of the sensible
heat storage for parabolic trough application
Salt No System Energy Density
500degC (MJm3)
0 NaNO3- KNO3 756
1 LiNO3-NaNO3-KNO3 1162
2 NaNO3- NaNO2- KNO3 1135
3 LiNO3-NaNO
3-KNO
3-MgKN 1099
4 LiNO3- NaNO
3- KNO
3- NaNO
2 1189
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1232
6 LiNO3-NaNO3-KNO3-KNO2 1174
7 LiNO3-KNO3-NaNO2-KNO2 1183
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1192
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 1242
93
Fig 624 Gravimetric storage density comparison of different energy storage systems as
function of temperature
Table 612 Gravimetric storage densities for solar salt and new molten salts
Salt
No System
Gravimetric Storage Density
500degC (kJkg)
0 NaNO3- KNO3 404
1 LiNO3-NaNO3-KNO3 560
2 NaNO3- NaNO2- KNO3 533
3 LiNO3-NaNO
3-KNO
3-MgKN 575
4 LiNO3- NaNO
3- KNO
3- NaNO
2 612
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 595
6 LiNO3-NaNO3-KNO3-KNO2 594
7 LiNO3-KNO3-NaNO2-KNO2 604
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 610
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 649
94
CHAPTER 7
CONCLUSION
The melting points of new molten salts were experimentally determined using DSC
Different from metals the melting point was chosen as the peak temperature rather than onset
temperature of the endothermic peak due to the low thermal conductivity and broad phase
transition range of the molten nitride salt mixture All of the nine new molten salts have melting
points from 89oC to 124
oC which are much lower than current sodium-potassium binary solar
salt Some systems such as salt No1 No7 and No8 have solid phase transformation observed
from the DSC plots It is found that the phase transformations of salt No 7 and No 8 are mainly
contributed to the KNO3-NaNO2 binary system while the small solid transformation peak of salt
No1 is resulted from the combined effect of the KNO3-LiNO3 eutectic binary system involved in
the ternary salt and another binary system which is composed of the rest components The
heating rate of DSC was revealed as a significant parameter for the any endothermic peak
determination When using lower heating rate the thermal resistance between the studied sample
and the furnace will be minimal and the resolution of peak detection will be enhanced
The heat capacities of all the multi-component salts (1 to 9) were determined using DSC
and found varying from 143 to 161 JgK at 350oC The heat capacity in the liquid state
demonstrates linear increase trend as function of temperature On the basis of that the heat
capacity was extrapolated to parabolic trough operating temperature of 500oC Besides heat
capacity data as function of temperature are fit to polynomial equation and thermodynamic
95
properties like enthalpy entropy and Gibbs energies of the compound as function of temperature
are subsequently deduced
Experimental measurements of density of multi-component systems were conducted as
function of temperature in their liquid state In liquid state the density values decrease linearly
as temperature increases The results of those mixtures were compared to the solar salt and
individual constituent salts The comparison demonstrates that the addition of lithium nitrate
lowers the density which is consistent with the observation that lithium nitrate has the lowest
density among all the individual salts in the studied temperature range On the basis of densities
heat capacities and the melting points energy storage density for all the new salts were
calculated and compared to the binary solar salt Among all the new molten salt systems
LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN quinary system (salt 9) presents the largest thermal
energy storage density as well as the gravimetric density values Moreover the larger thermal
energy storage as well as gravimetric storage densities compared to the solar salt indicate the
better energy storage capacities of new salts for solar power generation systems
96
REFERENCES
[1] JF Manwell JG McGowan and AL Rogers Wind Energy Explained-Theory Design and
Application second edition John Wiley and sons Ltd UK 2009
[2] MJ Pasqualetti Morality space and the power of wind-energy landscapes Geographical
Review 90 2000 381-394
[3] DG Fink and HW Beaty Standard Handbook for Electrical Engineers Eleventh Edition
McGraw-Hill New York 1978
[4] R Bertani Geothermal Energy An Overview on Resources and Potential Proceedings of the
International Conference on National Development of Geothermal Energy Use 2009 Slovakia
[5] TA Volk LP Abrahamson EH White E Neuhauser E Gray C Demeter C Lindsey J
Jarnefeld DJ Aneshansley R Pellerin and S Edick Developing a Willow Biomass Crop
Enterprise for Bioenergy and Bioproducts in the United States Proceedings of Bioenergy
2000 October 15-19 2000 Buffalo New York USA
[6] M Asplund N Grevesse and AJ Sauval The new solar abundances-Part I the
observations Communications in Asteroseismology 147 2006 76-79
[7] DRWilliams Sun Fact Sheet NASA 2004
httpnssdcgsfcnasagovplanetaryfactsheetsunfacthtml
[8] U Herrmann Survey of Thermal Energy Storage for Parabolic Trough Power Plants Journal
of Solar Energy Engineering 124 2002 145-152
[9] Rocket Research Company Chemical energy storage for solar thermal conversion SAND79-
8198 Livermore Sandia National Laboratories 1979
97
[10] A Steinfeld and R Palumbo Solar thermochemical process technology Encyclopedia of
Physical Science and Technology 2001 237-256
[11] EA Fletcher Solar thermal processing a review Journal of Solar Energy Engineering
2001 63-74
[12] R W Bradshaw and Nathan P Siegel Molten Nitrate Salt Development for Thermal
Energy Storage in Parabolic Trough Solar Power Systems of the Energy Sustainability 2008
Conference August 10-14 2008 Jacksonville Florida USA
[13] B Kelly H Price D Brosseau and D Kearney Adopting NitrateNitrite Salt Mixtures as
the Heat Transport Fluid in Parabolic Trough Power Plants Proceedings of the Energy
Sustainability 2007 Conference June 27-30 2007 Long Beach CA
[14] H Reilly and G Kolb Evaluation of Molten Salt Power Tower Technology Based on
Experience at Solar Two SAND2001-3674 Sandia National Laboratories 2001
[15] T Wendelin ldquoParabolic Trough VSHOT Optical Characterization in 2005-2006rdquo NREL
wwwnrelgovdocsfy06osti40024pdf
[16] RB Diver C Andraka S Rawlinson V Goldberg and G Thomas The Advanced Dish
Development System Project ASME Proceedings of Solar Forum 2001 Washington DC
[17] S D Odeh G L Morrison and M Behnia Modelling of parabolic trough direct steam
generation solar collectors Solar Energy 62 1998 396-406
[18] V Heinzel H Kungle and M Simon Simulation of a parabolic trough collector ISES
Solar World Congress Harare Zimbabwe 1-10
[19] S D Odeh G L Morrison and M Behnia Modeling of Parabolic Trough Direct
Generation Solar Collectors Solar Energy 62 1998 395-406
[20] Ezzat Optimum Working Fluids for Solar Powered Rankine Cycle Cooling of Buildings
Solar energy 25 1980 235-241
98
[21] R G Reddy Ionic Liquids How well do we know them editorial Journal of Phase
Equilibria and Diffusion 27 2006 210-211
[22] M Zhang and R G Reddy Application of [C4min][Tf2N] Ionic Liquid as Thermal
Storage and Heat Transfer Fluids editor J Weidner ECS Transactions 2 (28) 2007 27-32
[23] M Zhang and R G Reddy Evaluation of Ionic Liquids as Heat Transfer Materials in
Thermal Storage Systems Energy Energy Materials editors F Dogan M Awano D Singh
and B Tuttle ASM International Materials Park Ohio USA MSampT‟07 2007 151-160
[24] R G Reddy Novel Applications of Ionic Liquids in Materials Processing Advanced
Structural and Functional Materials Design 2008 Journal of Physics Conference Series (JPCS)
165 2009 1-6
[25] RW Bradshaw and DE Meeker High-temperature stability of ternary nitrate molten
salts for solar thermal energy systems Solar Energy Materials 21 1990 51-60
[26] AS Trunin Designing and investigations of salt systems for solar energy utilization
Utilization of sun and other radiation sources in materials research Kiev Naukova Dumka 1983
p 228-38
[27] D J Rogers and G J Janz Melting-crystallization and premelting properties of sodium
nitrate-potassium nitrate Enthalpies and heat capacities Journal of Chemical and Engineering
Data 27 1982 424-428
[28] D Kearney U Herrmann P Nava and B Kelly Assessment of a molten salt heat transfer
fluid in a parabolic trough solar field Journal of Solar Energy Engineering 125 2003 170-176
[29] Q Peng J Ding X Wei J Yang and X Yang The preparation and properties of multi-
component molten salts Applied Energy 87 2010 2812-2817
[30] E M Levin C R Robbins and H F McMordie Phase Diagrams for Ceramists American
Ceramic Society 1964
[31] J C Oxley J L Smith E Rogers and M Yu Ammonium nitrate thermal stability and
explosivity modifiers Thermochimica Acta 384 2002 23-45
99
[32] LG Marianowski and HC Maru Latent heat thermal energy storage systems above
4508oC Proceedings of 12th intersociety energy conversion engineering conference 1977 55-
66
[33] HC Maru JF Dullea A Kardas L Paul LG Marianowski E Ong et al Molten salts
energy storage systems Chicago Final Report of the Institute of Gas Technology 1978
[34] WM Philips and JW Stears Advanced latent heat of fusion thermal energy storage for
solar power stations Proceedings of 20th intersociety energy conversion engineering conference
2 1985 384-391
[35] KE Mayo Heat source systems USA Patent 3605720 1971
[36] JI Eichelberger and HD Gillman Investigation of metal fluoride thermal energy storage
material Proceedings of 12th intersociety energy conversion engineering conference 1977 567-
574
[37] GR Heidenreich and MB Parekh Thermal energy storage for organic Rankine cycle solar
dynamic space power systems Proceedings of 21st intersociety energy conversion engineering
conference 2 1986 791-797
[38] IK Garkushin AC Trunin TT Miftakhov and MA Dibirov Salt heat storage
composition USSR Patent 1036734 1983
[39] W M Philips and J W Stears Advanced latent heat of fusion thermal energy storage for
solar power stations In Proceedings of 20th intersociety energy conversion engineering
conference 2 1985 384-391
[40] Y Takahashi M Kamimoto Y Abe R Sakamoto K Kanari and T Ozawa Investigation
of latent heat-thermal energy storage materials IV Thermoanalitical evaluation of binary eutectic
mixtures of NaOH with LiOH or KOH Thermochim Acta 121 1987 193-202
[41] C E Birchenall and A F Riechman Heat storage in eutectic alloys Metall Trans A
11A(8) 1980 1415-1420
100
[42] Y Takahashi R Sakamoto and M Kamimoto Heat capacities and latent heats of LiNO3
NaNO3 and KNO3 International Journal of Thermophysics 9(6) 1988 1081-1090
[43] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate Mixtures
Journal of Chemical Engineering Data 8(3) 1963 469
[44] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical Engineering Data 6 (4) 1961 493
[45] GF Petersen WA Ewing and G P Smith Densities of Some Salt Mixtures Journal of
Chemical Engineering Data 6 (4) 1961 540
[46] G J Janz and M R Lorenz Precise Measurement of Density and Surface Tension at
Temperatures up to 1000degC in One Apparatus Review of Scientific Instruments 31 (1) 1960
18-23
[47] G J Janz C B Allen N P Bansal R M Murphy and R P Tomkins Physical Properties
Data Compilations Relevant to Energy Storage II Molten Salts Data on Single and Multi-
Component Salt Systems National Bureau of Standards NSRDS-NBS 61 Part II April 1979
[48] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation Equations
for Critically Evaluated Density Surface Tension Electrical Conductance and Viscosity Data
Journal of Physical and Chemical Reference Data 17 1988 2
[49] A T Ward and G J Janz Molten Carbonate Electrolytes Electiral Conductance Density
and Surface Tension of Binary and Ternary Eleclrochimica Acta 10 1965 849-857
[50] Y Takahashi R Sakamoto and MKamimoto Heat Capacities and Latent Heat of LiNO3
NaNO3 amp KNO3 International Journal of Thermophysics 9 1998 1081-1090
[51] R W Carling Heat capacities of NaNO3 and KNO3 up to 800 K Thermochimica Acta 60
1983 265-275
[52] Y Takahashi Latent heat measurement by DSC with sapphire as standard material
Thermochim Acta 88(1) 1985 199-204
101
[53] GW Hohne W Hemminger and HJ Flammersheim Differential Scanning Calorimetry
Springer-Verlag Berlin 1996
[54] W Hemminger and G Hohne Calorimetry Fundamentals and Practice Verlag Weinheim
1984
[55] M Merzlyakov and C Schick Thermal conductivity from dynamic response of DSC
Thermochimica Acta 377 2001 183-191
[56] T Kousksou A Jamil S Gibout and Y Zeraouli Thermal analysis of phase change
emulsion Journal of Thermal Analysis and Calorimetry 96 2009 841-852
[57] A Jamil T Kousksou K El Omari Y Zeraouli and Y Le Guer Heat transfer in salt
solutions enclosed in DSC cells Thermochimica Acta 507-508 2010 15-20
[58] MJ Richardson Quantitative aspects of differential scanning calorimetry Thermochimica
Acta 300 1997 15-28
[59] S Rudtsch Uncertainty of heat capacity measurements with differential scanning
calorimeters Thermochimica Acta 382 2002 17-25
[60] M J Maeso and J Largo The phase diagram of LiNO3-NaNO3 and LiNO3-KNO3 the
behavior of liquid mixtures Thermochimica Acta 223 (1993) 145-156
[61] O J Kleppa A new twin high-temperature reaction calorimeter The heats of mixing in
liquid sodium-potassium nitrates Journal of Physical Chemistry 64(12) (1960) 1937-1940
[62] G W H Hhne H K Cammenga W Eysel E Gmelin and W Hemminger The
Temperature Calibration of Scanning Calorimeters Thermochimica Acta 160 1990 1-12
[63] L B Pankratz Thermodynamic Properties of Carbides Nitrides and Other Selected
Substances U S Bureau of Mines Bulletin 696 1994
[64] M Zhang and R G Reddy Thermodynamic properties of C4mim[Tf2N] ionic liquids 0 2
2010 71-76
102
[65] D Mantha T Wang and R G Reddy Thermodynamic Modeling of Eutectic Point in the
LiNO3-NaNO3-KNO3 Ternary System Journal of Phase Equilibria and Diffusion 2011
(accepted)
[66] R G Reddy T Wang and D Mantha Determination of thermodynamic properties of
2KNO3Mg(NO3)2 Thermochimica Acta 2011 (submitted)
[67] T Wang D Mantha and R G Reddy Thermal stability of new LiNO3-NaNO3-KNO3
ternary salt for thermal energy storage system (in preparation)
[68] G D Carvalho E Frollini and W N D Santos Thermal conductivity of polymers by hot-
wire method J Appl Poly Sci 62 (1996) 2281-2285
[69] H Bloom A Doroszkowski and S B Tricklebank Molten salt mixtures IX The thermal
conductivities of molten nitrate systems Aus J Chem 18(8) (1965) 1171-1176
[70] A G Turnbull Thermal conductivity of molten salts Aus J Appl Sci 12 (1961) 30-41
[71] L R White and H T Davis Thermal conductivity of molten alkali nitrates J Chem Phys
47(1967) 5433-5439
[72] M V Peralta-Martinez M J Assael M J Dix L Karagiannidis and W A Wakeham A
Novel Instrument for the Measurement of the Thermal Conductivity of Molten Metal Part1
Instrument‟s Description Int J Thermophysics 27 (2006) 353-375
[73] Y Tada M Harada M Tanlgakl and W Eguchl Laser Flash Method for Measuring
Thermal Conductivity of Liquids Application to Molten Salts Industrial and Engineering
Chemistry Fundamentals 20 1981 333- 336
[74] M V Smirnov V A Khokhlov and E S Filatov Thermal conductivity of molten alkali
halides and their mixtures Electrochimica Acta 32 (1986) 1019-1026
[75] E Marti E Kaisersberger and W D Emmerich NEW ASPECTS OF THERMAL
ANALYSIS Part I Resolution of DSC and means for its optimization Journal of Thermal
Analysis and Calorimetry 77 2004 905-934
103
[76] E Marti E Kaisersberger G Kaiser and WY Ma Netzsch Annual 2000
bdquoThermoanalytical Characterization of Pharmaceuticals‟ Netzsch-Geraumltebau GmbH D-95100
SelbBavaria
[77] P J van Ekeren C M Holl and A J Witteveen A comparative test of differential
scanning calorimeters Journal of Thermal Analysis and Calorimetry 49 1997 1105-1114
[78] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation
Equations for Critically Evaluated Density Surface Tension Electrical Conductance and
Viscosity Data Journal of Physical and Chemical Reference Data 17 1988 1
[79] G F Petersen W A Ewing and G P Smith ldquoDensities of Some Salt Mixturesrdquo Journal of
Chemical and Engineering Data 6 1961 540
[80] P M Nasch and S G Steinemann Density and Thermal Expansion of Molten Manganese
Iron Nickel Copper Aluminum and Tin by Means of the Gamma-Ray Attenuation Technique
Physics and Chemistry of Liquids 29 1995 43-58
[81] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical and Engineering Data 6 1961 493-496
[82] D A Nissen Thermophysical Properties of the Equimolar Mixture NaNO3-KNO3 from
300degC to 600degC Journal of Chemical and Engineering Data 27 1982 269-273
[83] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate
Mixtures Journal of Chemical and Engineering Data 8 1963 469
104
APPENDIX
Appendix A
Table A1 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in solid state
(29815-40315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 342 1290 417 -025
299 027 008 000 343 1317 426 -026
300 059 018 000 344 1345 436 -027
301 091 028 000 345 1372 445 -028
302 123 037 000 346 1399 455 -029
303 154 047 000 347 1427 464 -031
304 186 056 000 348 1454 474 -032
305 217 066 000 349 1481 483 -033
306 248 076 000 350 1508 493 -035
307 279 085 000 351 1535 503 -036
308 310 095 -001 352 1562 512 -038
309 340 104 -001 353 1589 522 -039
310 371 114 -001 354 1616 532 -041
311 401 123 -001 355 1643 541 -042
312 432 133 -002 356 1670 551 -044
313 462 142 -002 357 1697 561 -045
314 492 152 -002 358 1724 570 -047
315 521 161 -003 359 1751 580 -048
316 551 171 -003 360 1777 590 -050
317 581 180 -004 361 1804 600 -052
318 610 190 -004 362 1831 610 -053
319 640 199 -005 363 1858 619 -055
320 669 209 -005 364 1885 629 -057
105
321 698 218 -006 365 1911 639 -059
322 727 228 -007 366 1938 649 -060
323 756 237 -007 367 1965 659 -062
324 785 246 -008 368 1992 669 -064
325 814 256 -009 369 2018 679 -066
326 842 265 -009 370 2045 689 -068
327 871 275 -010 371 2072 699 -070
328 899 284 -011 372 2098 709 -072
329 928 294 -012 373 2125 719 -074
330 956 303 -012 374 2152 729 -076
331 984 313 -013 375 2179 739 -078
332 1012 322 -014 376 2205 750 -080
333 1041 331 -015 377 2232 760 -082
334 1069 341 -016 378 2259 770 -084
335 1096 350 -017 379 2286 780 -086
336 1124 360 -018 380 2312 791 -088
337 1152 369 -019 381 2339 801 -090
338 1180 379 -020 382 2366 811 -093
339 1207 388 -021 383 2393 822 -095
340 1235 398 -022 384 2420 832 -097
341 1263 407 -023 38415 2424 834 -097
Table A2 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in liquid state
(40315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
40315 4287 1565 -163 514 7070 2838 -796
404 4310 1575 -167 515 7094 2850 -803
405 4337 1585 -171 516 7117 2863 -810
406 4363 1596 -175 517 7141 2875 -817
407 4390 1607 -180 518 7165 2887 -824
408 4417 1618 -184 519 7188 2899 -831
409 4443 1629 -189 520 7212 2911 -839
410 4470 1640 -193 521 7235 2924 -846
411 4496 1651 -197 522 7259 2936 -853
412 4523 1662 -202 523 7282 2948 -860
106
413 4549 1672 -206 524 7306 2960 -868
414 4576 1683 -211 525 7329 2973 -875
415 4602 1694 -216 526 7352 2985 -882
416 4629 1705 -220 527 7376 2997 -890
417 4655 1716 -225 528 7399 3010 -897
418 4681 1727 -230 529 7422 3022 -904
419 4708 1738 -234 530 7446 3034 -912
420 4734 1749 -239 531 7469 3047 -919
421 4760 1760 -244 532 7492 3059 -927
422 4786 1771 -249 533 7516 3071 -934
423 4813 1782 -253 534 7539 3084 -942
424 4839 1793 -258 535 7562 3096 -949
425 4865 1804 -263 536 7585 3109 -957
426 4891 1816 -268 537 7608 3121 -965
427 4917 1827 -273 538 7632 3134 -972
428 4943 1838 -278 539 7655 3146 -980
429 4969 1849 -283 540 7678 3158 -988
430 4995 1860 -288 541 7701 3171 -995
431 5021 1871 -293 542 7724 3183 -1003
432 5046 1882 -298 543 7747 3196 -1011
433 5072 1894 -303 544 7770 3208 -1018
434 5098 1905 -308 545 7793 3221 -1026
435 5124 1916 -313 546 7816 3233 -1034
436 5149 1927 -318 547 7839 3246 -1042
437 5175 1938 -323 548 7862 3259 -1050
438 5201 1950 -328 549 7885 3271 -1058
439 5226 1961 -334 550 7908 3284 -1066
440 5252 1972 -339 551 7931 3296 -1073
441 5278 1983 -344 552 7953 3309 -1081
442 5303 1995 -349 553 7976 3322 -1089
443 5329 2006 -355 554 7999 3334 -1097
444 5354 2017 -360 555 8022 3347 -1105
445 5380 2028 -365 556 8045 3359 -1113
446 5405 2040 -371 557 8067 3372 -1121
447 5430 2051 -376 558 8090 3385 -1130
448 5456 2062 -382 559 8113 3398 -1138
449 5481 2074 -387 560 8136 3410 -1146
450 5506 2085 -393 561 8158 3423 -1154
451 5532 2097 -398 562 8181 3436 -1162
452 5557 2108 -404 563 8204 3448 -1170
107
453 5582 2119 -409 564 8226 3461 -1178
454 5607 2131 -415 565 8249 3474 -1187
455 5633 2142 -421 566 8271 3487 -1195
456 5658 2154 -426 567 8294 3499 -1203
457 5683 2165 -432 568 8317 3512 -1212
458 5708 2177 -438 569 8339 3525 -1220
459 5733 2188 -443 570 8362 3538 -1228
460 5758 2200 -449 571 8384 3551 -1237
461 5783 2211 -455 572 8407 3564 -1245
462 5808 2223 -461 573 8429 3576 -1253
463 5833 2234 -466 574 8452 3589 -1262
464 5858 2246 -472 575 8474 3602 -1270
465 5883 2257 -478 576 8496 3615 -1279
466 5907 2269 -484 577 8519 3628 -1287
467 5932 2280 -490 578 8541 3641 -1296
468 5957 2292 -496 579 8564 3654 -1304
469 5982 2304 -502 580 8586 3667 -1313
470 6007 2315 -508 581 8608 3680 -1322
471 6031 2327 -514 582 8631 3693 -1330
472 6056 2339 -520 583 8653 3706 -1339
473 6081 2350 -526 584 8675 3719 -1348
474 6105 2362 -532 585 8697 3732 -1356
475 6130 2373 -538 586 8720 3745 -1365
476 6155 2385 -544 587 8742 3758 -1374
477 6179 2397 -551 588 8764 3771 -1382
478 6204 2409 -557 589 8786 3784 -1391
479 6228 2420 -563 590 8808 3797 -1400
480 6253 2432 -569 591 8831 3810 -1409
481 6277 2444 -575 592 8853 3823 -1418
482 6301 2456 -582 593 8875 3836 -1426
483 6326 2467 -588 594 8897 3849 -1435
484 6350 2479 -594 595 8919 3863 -1444
485 6375 2491 -601 596 8941 3876 -1453
486 6399 2503 -607 597 8963 3889 -1462
487 6423 2515 -614 598 8985 3902 -1471
488 6448 2526 -620 599 9007 3915 -1480
489 6472 2538 -626 600 9029 3928 -1489
490 6496 2550 -633 601 9051 3942 -1498
491 6520 2562 -639 602 9073 3955 -1507
492 6544 2574 -646 603 9095 3968 -1516
108
493 6569 2586 -653 604 9117 3981 -1525
494 6593 2598 -659 605 9139 3994 -1535
495 6617 2610 -666 606 9161 4008 -1544
496 6641 2621 -672 607 9183 4021 -1553
497 6665 2633 -679 608 9205 4034 -1562
498 6689 2645 -686 609 9226 4048 -1571
499 6713 2657 -692 610 9248 4061 -1581
500 6737 2669 -699 611 9270 4074 -1590
501 6761 2681 -706 612 9292 4088 -1599
502 6785 2693 -713 613 9314 4101 -1608
503 6809 2705 -719 614 9335 4114 -1618
504 6833 2717 -726 615 9357 4128 -1627
505 6856 2729 -733 616 9379 4141 -1636
506 6880 2741 -740 617 9401 4154 -1646
507 6904 2754 -747 618 9422 4168 -1655
508 6928 2766 -754 619 9444 4181 -1665
509 6952 2778 -761 620 9466 4195 -1674
510 6975 2790 -768 621 9487 4208 -1684
511 6999 2802 -775 622 9509 4222 -1693
512 7023 2814 -782 623 9531 4235 -1703
513 7047 2826 -789 62315 9534 4237 -1704
109
Appendix B
Table B1 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(29815-39215K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 347 1233 382 -046
299 022 006 000 348 1258 390 -048
300 049 014 -001 349 1283 398 -049
301 075 022 -001 350 1307 406 -051
302 101 029 -001 351 1332 415 -053
303 127 037 -002 352 1356 423 -054
304 153 044 -002 353 1381 431 -056
305 179 052 -003 354 1405 440 -058
306 205 059 -003 355 1430 448 -060
307 230 067 -004 356 1455 456 -061
308 256 075 -004 357 1479 465 -063
309 282 082 -005 358 1504 473 -065
310 308 090 -005 359 1528 482 -067
311 333 098 -006 360 1553 490 -069
312 359 105 -007 361 1577 498 -071
313 384 113 -007 362 1602 507 -073
314 410 121 -008 363 1626 515 -075
315 435 128 -009 364 1651 524 -077
316 461 136 -010 365 1675 533 -079
317 486 144 -010 366 1700 541 -081
318 511 151 -011 367 1724 550 -083
319 537 159 -012 368 1749 558 -085
320 562 167 -013 369 1773 567 -087
321 587 175 -014 370 1798 576 -089
322 612 182 -015 371 1822 584 -092
323 637 190 -016 372 1847 593 -094
324 663 198 -017 373 1871 602 -096
325 688 206 -018 374 1896 611 -098
326 713 214 -019 375 1920 620 -100
327 738 222 -020 376 1945 628 -103
328 763 229 -021 377 1969 637 -105
329 788 237 -022 378 1994 646 -107
110
330 813 245 -023 379 2018 655 -110
331 838 253 -024 380 2043 664 -112
332 863 261 -025 381 2068 673 -115
333 887 269 -027 382 2092 682 -117
334 912 277 -028 383 2117 691 -120
335 937 285 -029 384 2141 700 -122
336 962 293 -030 385 2166 709 -125
337 987 301 -032 386 2191 718 -127
338 1011 309 -033 387 2215 727 -130
339 1036 317 -034 388 2240 737 -132
340 1061 325 -036 389 2265 746 -135
341 1086 333 -037 390 2289 755 -138
342 1110 341 -039 391 2314 764 -140
343 1135 349 -040 392 2339 774 -143
344 1160 357 -042 39215 2342 775 -144
345 1184 365 -043
Table B2 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(41315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
414 3280 1149 -209 520 5608 2235 -682
415 3302 1158 -212 521 5630 2246 -687
416 3325 1167 -216 522 5651 2257 -693
417 3348 1177 -219 523 5672 2268 -698
418 3370 1186 -223 524 5694 2279 -704
419 3393 1196 -226 525 5715 2290 -710
420 3416 1205 -229 526 5736 2302 -716
421 3438 1215 -233 527 5757 2313 -721
422 3461 1224 -236 528 5779 2324 -727
423 3483 1234 -240 529 5800 2335 -733
424 3506 1243 -243 530 5821 2347 -739
425 3529 1253 -247 531 5842 2358 -745
426 3551 1263 -250 532 5864 2369 -750
427 3574 1272 -254 533 5885 2380 -756
428 3596 1282 -257 534 5906 2392 -762
429 3619 1291 -261 535 5927 2403 -768
111
430 3641 1301 -265 536 5948 2414 -774
431 3663 1311 -268 537 5970 2426 -780
432 3686 1320 -272 538 5991 2437 -786
433 3708 1330 -276 539 6012 2449 -792
434 3731 1340 -279 540 6033 2460 -798
435 3753 1350 -283 541 6054 2471 -804
436 3775 1359 -287 542 6075 2483 -810
437 3798 1369 -291 543 6096 2494 -816
438 3820 1379 -294 544 6118 2506 -822
439 3842 1389 -298 545 6139 2517 -828
440 3865 1398 -302 546 6160 2529 -835
441 3887 1408 -306 547 6181 2540 -841
442 3909 1418 -310 548 6202 2552 -847
443 3932 1428 -314 549 6223 2563 -853
444 3954 1438 -318 550 6244 2575 -859
445 3976 1448 -322 551 6265 2586 -866
446 3998 1458 -326 552 6286 2598 -872
447 4021 1468 -330 553 6307 2610 -878
448 4043 1477 -334 554 6328 2621 -884
449 4065 1487 -338 555 6349 2633 -891
450 4087 1497 -342 556 6370 2645 -897
451 4109 1507 -346 557 6391 2656 -904
452 4131 1517 -350 558 6412 2668 -910
453 4154 1527 -354 559 6433 2680 -916
454 4176 1537 -358 560 6454 2691 -923
455 4198 1547 -363 561 6475 2703 -929
456 4220 1557 -367 562 6496 2715 -936
457 4242 1568 -371 563 6517 2727 -942
458 4264 1578 -375 564 6538 2738 -949
459 4286 1588 -380 565 6559 2750 -955
460 4308 1598 -384 566 6580 2762 -962
461 4330 1608 -388 567 6600 2774 -969
462 4352 1618 -393 568 6621 2786 -975
463 4374 1628 -397 569 6642 2798 -982
464 4396 1639 -401 570 6663 2810 -988
465 4418 1649 -406 571 6684 2821 -995
466 4440 1659 -410 572 6705 2833 -1002
467 4462 1669 -415 573 6726 2845 -1009
468 4484 1680 -419 574 6747 2857 -1015
469 4506 1690 -424 575 6767 2869 -1022
112
470 4528 1700 -428 576 6788 2881 -1029
471 4550 1710 -433 577 6809 2893 -1036
472 4572 1721 -437 578 6830 2905 -1042
473 4593 1731 -442 579 6851 2917 -1049
474 4615 1741 -446 580 6871 2929 -1056
475 4637 1752 -451 581 6892 2941 -1063
476 4659 1762 -456 582 6913 2953 -1070
477 4681 1773 -460 583 6934 2966 -1077
478 4703 1783 -465 584 6954 2978 -1084
479 4724 1793 -470 585 6975 2990 -1091
480 4746 1804 -474 586 6996 3002 -1098
481 4768 1814 -479 587 7017 3014 -1105
482 4790 1825 -484 588 7037 3026 -1112
483 4812 1835 -489 589 7058 3038 -1119
484 4833 1846 -494 590 7079 3051 -1126
485 4855 1856 -498 591 7100 3063 -1133
486 4877 1867 -503 592 7120 3075 -1140
487 4898 1877 -508 593 7141 3087 -1147
488 4920 1888 -513 594 7162 3100 -1154
489 4942 1899 -518 595 7182 3112 -1162
490 4963 1909 -523 596 7203 3124 -1169
491 4985 1920 -528 597 7224 3137 -1176
492 5007 1930 -533 598 7244 3149 -1183
493 5028 1941 -538 599 7265 3161 -1190
494 5050 1952 -543 600 7285 3174 -1198
495 5072 1962 -548 601 7306 3186 -1205
496 5093 1973 -553 602 7327 3198 -1212
497 5115 1984 -558 603 7347 3211 -1220
498 5136 1995 -563 604 7368 3223 -1227
499 5158 2005 -568 605 7389 3236 -1234
500 5180 2016 -574 606 7409 3248 -1242
501 5201 2027 -579 607 7430 3261 -1249
502 5223 2038 -584 608 7450 3273 -1257
503 5244 2049 -589 609 7471 3286 -1264
504 5266 2059 -595 610 7491 3298 -1272
505 5287 2070 -600 611 7512 3311 -1279
506 5309 2081 -605 612 7532 3323 -1287
507 5330 2092 -610 613 7553 3336 -1294
508 5352 2103 -616 614 7573 3348 -1302
509 5373 2114 -621 615 7594 3361 -1309
113
510 5394 2125 -627 616 7615 3374 -1317
511 5416 2136 -632 617 7635 3386 -1325
512 5437 2147 -637 618 7656 3399 -1332
513 5459 2158 -643 619 7676 3412 -1340
514 5480 2169 -648 620 7696 3424 -1348
515 5502 2180 -654 621 7717 3437 -1355
516 5523 2191 -659 622 7737 3450 -1363
517 5544 2202 -665 623 7758 3462 -1371
518 5566 2213 -670 62315 7761 3464 -1372
114
Appendix C
Table C1 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in solid
state (29815-36415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 333 1937 611 -034
299 048 014 000 334 1992 629 -036
300 104 031 000 335 2047 647 -038
301 160 048 000 336 2102 666 -040
302 216 065 000 337 2156 684 -042
303 272 082 -001 338 2211 703 -045
304 329 099 -001 339 2266 721 -047
305 385 116 -001 340 2321 740 -049
306 441 133 -002 341 2375 758 -052
307 496 150 -002 342 2430 777 -054
308 552 167 -003 343 2485 796 -056
309 608 185 -003 344 2539 815 -059
310 664 202 -004 345 2594 833 -062
311 720 219 -005 346 2648 852 -064
312 776 236 -006 347 2703 871 -067
313 831 254 -006 348 2757 890 -070
314 887 271 -007 349 2812 909 -072
315 942 289 -008 350 2866 928 -075
316 998 306 -009 351 2921 947 -078
317 1054 324 -010 352 2975 966 -081
318 1109 341 -011 353 3029 985 -084
319 1164 359 -012 354 3084 1004 -087
320 1220 377 -014 355 3138 1024 -090
321 1275 395 -015 356 3192 1043 -094
322 1331 412 -016 357 3246 1062 -097
323 1386 430 -018 358 3300 1082 -100
324 1441 448 -019 359 3355 1101 -103
325 1496 466 -020 360 3409 1120 -107
326 1552 484 -022 361 3463 1140 -110
327 1607 502 -024 362 3517 1159 -114
328 1662 520 -025 363 3571 1179 -117
329 1717 538 -027 364 3625 1199 -121
115
330 1772 556 -029 36415 3633 1202 -121
331 1827 574 -030
332 1882 593 -032
Table C2 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in liquid
state (42115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
42115 7428 2673 -455 523 11788 4725 -1440
422 7468 2690 -461 524 11827 4745 -1452
423 7515 2710 -468 525 11866 4766 -1464
424 7562 2730 -476 526 11904 4786 -1476
425 7608 2750 -484 527 11943 4807 -1488
426 7655 2770 -491 528 11982 4827 -1500
427 7702 2790 -499 529 12021 4847 -1512
428 7748 2810 -507 530 12059 4868 -1524
429 7795 2830 -514 531 12098 4888 -1536
430 7841 2849 -522 532 12137 4909 -1548
431 7887 2869 -530 533 12175 4929 -1560
432 7933 2889 -538 534 12213 4950 -1572
433 7979 2909 -546 535 12252 4970 -1584
434 8025 2929 -554 536 12290 4991 -1597
435 8071 2949 -562 537 12328 5011 -1609
436 8117 2969 -570 538 12366 5032 -1621
437 8163 2989 -578 539 12404 5052 -1634
438 8208 3009 -586 540 12442 5073 -1646
439 8254 3029 -595 541 12480 5093 -1659
440 8299 3049 -603 542 12518 5114 -1671
441 8345 3069 -611 543 12556 5134 -1684
442 8390 3089 -620 544 12594 5155 -1696
443 8435 3109 -628 545 12632 5175 -1709
444 8480 3129 -636 546 12669 5196 -1721
445 8525 3149 -645 547 12707 5217 -1734
446 8570 3169 -654 548 12745 5237 -1747
116
447 8615 3189 -662 549 12782 5258 -1760
448 8659 3209 -671 550 12820 5278 -1772
449 8704 3229 -679 551 12857 5299 -1785
450 8748 3249 -688 552 12894 5319 -1798
451 8793 3269 -697 553 12932 5340 -1811
452 8837 3289 -706 554 12969 5361 -1824
453 8881 3309 -715 555 13006 5381 -1837
454 8926 3329 -724 556 13043 5402 -1850
455 8970 3349 -732 557 13080 5422 -1863
456 9014 3369 -741 558 13117 5443 -1876
457 9058 3389 -750 559 13154 5464 -1889
458 9102 3409 -760 560 13191 5484 -1902
459 9145 3429 -769 561 13228 5505 -1916
460 9189 3449 -778 562 13264 5526 -1929
461 9233 3469 -787 563 13301 5546 -1942
462 9276 3489 -796 564 13338 5567 -1956
463 9319 3509 -806 565 13374 5588 -1969
464 9363 3529 -815 566 13411 5608 -1982
465 9406 3549 -824 567 13447 5629 -1996
466 9449 3570 -834 568 13484 5650 -2009
467 9492 3590 -843 569 13520 5670 -2023
468 9535 3610 -853 570 13557 5691 -2036
469 9578 3630 -862 571 13593 5712 -2050
470 9621 3650 -872 572 13629 5732 -2063
471 9664 3670 -882 573 13665 5753 -2077
472 9707 3690 -891 574 13701 5774 -2091
473 9749 3710 -901 575 13737 5795 -2104
474 9792 3731 -911 576 13773 5815 -2118
475 9834 3751 -921 577 13809 5836 -2132
476 9877 3771 -930 578 13845 5857 -2146
477 9919 3791 -940 579 13881 5877 -2160
478 9961 3811 -950 580 13917 5898 -2174
479 10004 3831 -960 581 13953 5919 -2188
480 10046 3852 -970 582 13988 5940 -2202
481 10088 3872 -980 583 14024 5960 -2216
482 10130 3892 -990 584 14060 5981 -2230
483 10171 3912 -1001 585 14095 6002 -2244
484 10213 3932 -1011 586 14131 6023 -2258
485 10255 3953 -1021 587 14166 6044 -2272
486 10297 3973 -1031 588 14201 6064 -2286
117
487 10338 3993 -1042 589 14237 6085 -2300
488 10380 4013 -1052 590 14272 6106 -2315
489 10421 4034 -1062 591 14307 6127 -2329
490 10462 4054 -1073 592 14342 6148 -2343
491 10504 4074 -1083 593 14378 6168 -2358
492 10545 4094 -1094 594 14413 6189 -2372
493 10586 4114 -1104 595 14448 6210 -2386
494 10627 4135 -1115 596 14483 6231 -2401
495 10668 4155 -1126 597 14518 6252 -2415
496 10709 4175 -1136 598 14552 6273 -2430
497 10750 4196 -1147 599 14587 6293 -2444
498 10791 4216 -1158 600 14622 6314 -2459
499 10831 4236 -1169 601 14657 6335 -2474
500 10872 4256 -1179 602 14692 6356 -2488
501 10912 4277 -1190 603 14726 6377 -2503
502 10953 4297 -1201 604 14761 6398 -2518
503 10993 4317 -1212 605 14795 6419 -2533
504 11034 4338 -1223 606 14830 6439 -2547
505 11074 4358 -1234 607 14864 6460 -2562
506 11114 4378 -1245 608 14899 6481 -2577
507 11154 4399 -1257 609 14933 6502 -2592
508 11194 4419 -1268 610 14967 6523 -2607
509 11234 4439 -1279 611 15002 6544 -2622
510 11274 4460 -1290 612 15036 6565 -2637
511 11314 4480 -1302 613 15070 6586 -2652
512 11354 4500 -1313 614 15104 6607 -2667
513 11394 4521 -1324 615 15138 6628 -2682
514 11433 4541 -1336 616 15172 6649 -2697
515 11473 4562 -1347 617 15206 6670 -2713
516 11513 4582 -1359 618 15240 6691 -2728
517 11552 4602 -1370 619 15274 6712 -2743
518 11591 4623 -1382 620 15308 6733 -2758
519 11631 4643 -1393 621 15342 6754 -2774
520 11670 4664 -1405 622 15375 6774 -2789
521 11709 4684 -1417 623 15409 6795 -2804
522 11748 4704 -1428 62315 15414 6799 -2807
118
Appendix D
Table D1 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in solid state
(29815-36315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
299 021 006 000 333 867 277 -012
300 047 014 000 334 891 285 -012
301 072 022 000 335 916 293 -013
302 097 029 000 336 940 302 -014
303 122 037 000 337 964 310 -015
304 147 045 000 338 989 318 -016
305 172 053 000 339 1013 327 -017
306 197 060 000 340 1037 335 -018
307 223 068 000 341 1061 343 -019
308 248 076 000 342 1085 352 -019
309 273 084 000 343 1109 360 -020
310 298 092 -001 344 1134 369 -021
311 323 099 -001 345 1158 377 -022
312 348 107 -001 346 1182 385 -024
313 373 115 -001 347 1206 394 -025
314 398 123 -002 348 1230 402 -026
315 423 131 -002 349 1254 411 -027
316 447 139 -002 350 1277 419 -028
317 472 147 -003 351 1301 428 -029
318 497 155 -003 352 1325 436 -030
319 522 163 -003 353 1349 445 -032
320 547 171 -004 354 1373 453 -033
321 572 179 -004 355 1396 462 -034
322 596 187 -005 356 1420 470 -035
323 621 195 -005 357 1444 479 -037
324 646 203 -006 358 1467 487 -038
325 670 211 -006 359 1491 496 -039
326 695 220 -007 360 1514 504 -041
327 720 228 -008 361 1538 513 -042
328 744 236 -008 362 1561 522 -043
329 769 244 -009 363 1584 530 -045
330 793 252 -010 36315 1588 532 -045
119
331 818 260 -010
Table D2 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in liquid
state (38115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
38115 2281 765 -104 503 5639 2242 -594
382 2307 775 -106 504 5664 2255 -600
383 2338 787 -109 505 5689 2267 -606
384 2369 798 -111 506 5713 2280 -611
385 2399 810 -113 507 5738 2292 -617
386 2430 822 -116 508 5763 2305 -623
387 2460 834 -118 509 5787 2317 -629
388 2491 846 -121 510 5812 2330 -634
389 2521 857 -123 511 5836 2342 -640
390 2551 869 -126 512 5861 2355 -646
391 2582 881 -128 513 5885 2367 -652
392 2612 893 -131 514 5910 2380 -658
393 2642 905 -134 515 5934 2392 -664
394 2672 917 -136 516 5959 2405 -670
395 2702 928 -139 517 5983 2417 -676
396 2732 940 -142 518 6007 2430 -682
397 2762 952 -144 519 6032 2443 -688
398 2792 964 -147 520 6056 2455 -694
399 2821 976 -150 521 6080 2468 -700
400 2851 988 -153 522 6104 2480 -706
401 2881 999 -156 523 6128 2493 -712
402 2910 1011 -159 524 6152 2506 -718
403 2940 1023 -162 525 6176 2518 -724
404 2969 1035 -164 526 6200 2531 -731
405 2999 1047 -167 527 6224 2544 -737
406 3028 1059 -170 528 6248 2556 -743
407 3057 1071 -174 529 6272 2569 -749
408 3087 1083 -177 530 6296 2581 -756
120
409 3116 1095 -180 531 6320 2594 -762
410 3145 1107 -183 532 6344 2607 -768
411 3174 1119 -186 533 6368 2619 -775
412 3203 1130 -189 534 6391 2632 -781
413 3232 1142 -192 535 6415 2645 -787
414 3261 1154 -196 536 6439 2657 -794
415 3290 1166 -199 537 6462 2670 -800
416 3319 1178 -202 538 6486 2683 -807
417 3347 1190 -206 539 6510 2696 -813
418 3376 1202 -209 540 6533 2708 -820
419 3405 1214 -212 541 6557 2721 -826
420 3433 1226 -216 542 6580 2734 -833
421 3462 1238 -219 543 6604 2746 -839
422 3490 1250 -223 544 6627 2759 -846
423 3519 1262 -226 545 6650 2772 -853
424 3547 1274 -230 546 6674 2785 -859
425 3575 1286 -233 547 6697 2797 -866
426 3604 1298 -237 548 6720 2810 -873
427 3632 1310 -240 549 6744 2823 -879
428 3660 1322 -244 550 6767 2836 -886
429 3688 1334 -248 551 6790 2848 -893
430 3716 1346 -251 552 6813 2861 -900
431 3744 1358 -255 553 6836 2874 -907
432 3772 1371 -259 554 6860 2887 -913
433 3800 1383 -263 555 6883 2900 -920
434 3828 1395 -267 556 6906 2912 -927
435 3856 1407 -270 557 6929 2925 -934
436 3883 1419 -274 558 6952 2938 -941
437 3911 1431 -278 559 6975 2951 -948
438 3939 1443 -282 560 6998 2964 -955
439 3966 1455 -286 561 7020 2976 -962
440 3994 1467 -290 562 7043 2989 -969
441 4021 1479 -294 563 7066 3002 -976
442 4049 1491 -298 564 7089 3015 -983
443 4076 1504 -302 565 7112 3028 -990
444 4103 1516 -306 566 7134 3041 -997
445 4131 1528 -310 567 7157 3054 -1005
446 4158 1540 -314 568 7180 3066 -1012
447 4185 1552 -319 569 7203 3079 -1019
448 4212 1564 -323 570 7225 3092 -1026
121
449 4240 1576 -327 571 7248 3105 -1033
450 4267 1589 -331 572 7270 3118 -1041
451 4294 1601 -336 573 7293 3131 -1048
452 4321 1613 -340 574 7315 3144 -1055
453 4347 1625 -344 575 7338 3157 -1063
454 4374 1637 -349 576 7360 3170 -1070
455 4401 1650 -353 577 7383 3183 -1077
456 4428 1662 -357 578 7405 3196 -1085
457 4455 1674 -362 579 7428 3208 -1092
458 4481 1686 -366 580 7450 3221 -1100
459 4508 1698 -371 581 7472 3234 -1107
460 4535 1711 -375 582 7494 3247 -1114
461 4561 1723 -380 583 7517 3260 -1122
462 4588 1735 -384 584 7539 3273 -1129
463 4614 1747 -389 585 7561 3286 -1137
464 4641 1760 -394 586 7583 3299 -1145
465 4667 1772 -398 587 7605 3312 -1152
466 4693 1784 -403 588 7628 3325 -1160
467 4720 1796 -408 589 7650 3338 -1167
468 4746 1809 -412 590 7672 3351 -1175
469 4772 1821 -417 591 7694 3364 -1183
470 4798 1833 -422 592 7716 3377 -1191
471 4825 1846 -427 593 7738 3390 -1198
472 4851 1858 -432 594 7760 3403 -1206
473 4877 1870 -437 595 7782 3416 -1214
474 4903 1882 -441 596 7804 3429 -1222
475 4929 1895 -446 597 7825 3442 -1229
476 4955 1907 -451 598 7847 3455 -1237
477 4980 1919 -456 599 7869 3469 -1245
478 5006 1932 -461 600 7891 3482 -1253
479 5032 1944 -466 601 7913 3495 -1261
480 5058 1956 -471 602 7934 3508 -1269
481 5083 1969 -476 603 7956 3521 -1277
482 5109 1981 -481 604 7978 3534 -1285
483 5135 1994 -487 605 8000 3547 -1293
484 5160 2006 -492 606 8021 3560 -1301
485 5186 2018 -497 607 8043 3573 -1309
486 5211 2031 -502 608 8064 3586 -1317
487 5237 2043 -507 609 8086 3599 -1325
488 5262 2055 -513 610 8107 3613 -1333
122
489 5288 2068 -518 611 8129 3626 -1341
490 5313 2080 -523 612 8150 3639 -1349
491 5338 2093 -528 613 8172 3652 -1357
492 5364 2105 -534 614 8193 3665 -1366
493 5389 2117 -539 615 8215 3678 -1374
494 5414 2130 -545 616 8236 3692 -1382
495 5439 2142 -550 617 8258 3705 -1390
496 5464 2155 -555 618 8279 3718 -1398
497 5489 2167 -561 619 8300 3731 -1407
498 5514 2180 -566 620 8321 3744 -1415
499 5539 2192 -572 621 8343 3757 -1423
500 5564 2205 -578 622 8364 3771 -1432
501 5589 2217 -583 623 8385 3784 -1441
502 5614 2230 -589 62315 8388 3786 -1443
123
Appendix E
Table E1 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in solid state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 913 287 -014
299 025 007 000 331 941 296 -015
300 054 016 000 332 970 306 -016
301 083 025 000 333 998 315 -017
302 112 034 000 334 1026 324 -018
303 141 042 000 335 1054 334 -019
304 170 051 000 336 1081 343 -020
305 199 060 -001 337 1109 353 -021
306 228 069 -001 338 1137 362 -022
307 257 078 -001 339 1165 371 -024
308 286 087 -001 340 1193 381 -025
309 315 096 -002 341 1221 390 -026
310 343 105 -002 342 1248 400 -027
311 372 113 -002 343 1276 409 -028
312 401 122 -003 344 1304 419 -030
313 430 131 -003 345 1331 428 -031
314 458 140 -003 346 1359 438 -032
315 487 149 -004 347 1386 447 -034
316 516 159 -004 348 1414 457 -035
317 544 168 -005 349 1441 466 -036
318 573 177 -006 350 1468 476 -038
319 602 186 -006 351 1496 486 -039
320 630 195 -007 352 1523 495 -041
321 659 204 -007 353 1550 505 -042
322 687 213 -008 354 1577 514 -044
323 715 222 -009 355 1605 524 -046
324 744 232 -009 356 1632 534 -047
325 772 241 -010 357 1659 543 -049
326 800 250 -011 358 1686 553 -050
327 829 259 -012 359 1713 563 -052
328 857 269 -013 35915 1717 564 -052
329 885 278 -013
124
Table E2 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in liquid state (376-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2323 777 -094 500 5525 2173 -590
376 2347 786 -096 501 5548 2184 -595
377 2375 797 -098 502 5572 2196 -601
378 2403 808 -101 503 5595 2208 -606
379 2431 818 -103 504 5619 2220 -612
380 2459 829 -106 505 5642 2232 -618
381 2487 839 -108 506 5665 2243 -623
382 2515 850 -111 507 5689 2255 -629
383 2542 861 -113 508 5712 2267 -635
384 2570 871 -116 509 5735 2279 -640
385 2598 882 -118 510 5759 2291 -646
386 2626 893 -121 511 5782 2303 -652
387 2653 903 -123 512 5805 2315 -658
388 2681 914 -126 513 5828 2326 -664
389 2708 925 -129 514 5852 2338 -669
390 2736 935 -132 515 5875 2350 -675
391 2763 946 -134 516 5898 2362 -681
392 2791 957 -137 517 5921 2374 -687
393 2818 968 -140 518 5944 2386 -693
394 2845 978 -143 519 5967 2398 -699
395 2873 989 -146 520 5990 2410 -705
396 2900 1000 -148 521 6013 2422 -711
397 2927 1011 -151 522 6036 2434 -717
398 2954 1022 -154 523 6059 2446 -723
399 2981 1032 -157 524 6082 2458 -729
400 3008 1043 -160 525 6105 2470 -735
401 3035 1054 -163 526 6128 2482 -741
402 3062 1065 -166 527 6151 2494 -747
403 3089 1076 -169 528 6173 2506 -754
404 3116 1086 -172 529 6196 2518 -760
405 3143 1097 -176 530 6219 2530 -766
125
406 3170 1108 -179 531 6242 2542 -772
407 3197 1119 -182 532 6265 2554 -778
408 3223 1130 -185 533 6287 2566 -785
409 3250 1141 -188 534 6310 2578 -791
410 3277 1152 -192 535 6333 2591 -797
411 3303 1163 -195 536 6355 2603 -804
412 3330 1174 -198 537 6378 2615 -810
413 3356 1185 -202 538 6400 2627 -816
414 3383 1195 -205 539 6423 2639 -823
415 3409 1206 -208 540 6445 2651 -829
416 3436 1217 -212 541 6468 2663 -836
417 3462 1228 -215 542 6490 2676 -842
418 3488 1239 -219 543 6513 2688 -849
419 3515 1250 -222 544 6535 2700 -855
420 3541 1261 -226 545 6558 2712 -862
421 3567 1272 -229 546 6580 2724 -868
422 3593 1283 -233 547 6602 2737 -875
423 3619 1294 -236 548 6625 2749 -882
424 3645 1305 -240 549 6647 2761 -888
425 3671 1317 -244 550 6669 2773 -895
426 3697 1328 -247 551 6692 2786 -902
427 3723 1339 -251 552 6714 2798 -908
428 3749 1350 -255 553 6736 2810 -915
429 3775 1361 -259 554 6758 2822 -922
430 3801 1372 -262 555 6780 2835 -929
431 3827 1383 -266 556 6803 2847 -935
432 3852 1394 -270 557 6825 2859 -942
433 3878 1405 -274 558 6847 2872 -949
434 3904 1416 -278 559 6869 2884 -956
435 3929 1428 -282 560 6891 2896 -963
436 3955 1439 -286 561 6913 2909 -970
437 3981 1450 -290 562 6935 2921 -977
438 4006 1461 -294 563 6957 2933 -983
439 4032 1472 -298 564 6979 2946 -990
440 4057 1483 -302 565 7001 2958 -997
441 4083 1495 -306 566 7023 2971 -1004
442 4108 1506 -310 567 7045 2983 -1011
443 4133 1517 -314 568 7067 2995 -1019
444 4159 1528 -318 569 7089 3008 -1026
445 4184 1540 -322 570 7110 3020 -1033
126
446 4209 1551 -327 571 7132 3033 -1040
447 4234 1562 -331 572 7154 3045 -1047
448 4260 1573 -335 573 7176 3058 -1054
449 4285 1585 -339 574 7198 3070 -1061
450 4310 1596 -344 575 7219 3083 -1069
451 4335 1607 -348 576 7241 3095 -1076
452 4360 1618 -352 577 7263 3108 -1083
453 4385 1630 -357 578 7284 3120 -1090
454 4410 1641 -361 579 7306 3133 -1098
455 4435 1652 -365 580 7328 3145 -1105
456 4460 1664 -370 581 7349 3158 -1112
457 4485 1675 -374 582 7371 3170 -1120
458 4510 1687 -379 583 7393 3183 -1127
459 4534 1698 -383 584 7414 3195 -1134
460 4559 1709 -388 585 7436 3208 -1142
461 4584 1721 -393 586 7457 3221 -1149
462 4609 1732 -397 587 7479 3233 -1157
463 4633 1743 -402 588 7500 3246 -1164
464 4658 1755 -406 589 7522 3258 -1172
465 4683 1766 -411 590 7543 3271 -1179
466 4707 1778 -416 591 7564 3284 -1187
467 4732 1789 -420 592 7586 3296 -1194
468 4756 1801 -425 593 7607 3309 -1202
469 4781 1812 -430 594 7628 3322 -1210
470 4805 1824 -435 595 7650 3334 -1217
471 4830 1835 -440 596 7671 3347 -1225
472 4854 1847 -444 597 7692 3360 -1233
473 4878 1858 -449 598 7714 3373 -1240
474 4903 1870 -454 599 7735 3385 -1248
475 4927 1881 -459 600 7756 3398 -1256
476 4951 1893 -464 601 7777 3411 -1264
477 4975 1904 -469 602 7799 3423 -1271
478 5000 1916 -474 603 7820 3436 -1279
479 5024 1927 -479 604 7841 3449 -1287
480 5048 1939 -484 605 7862 3462 -1295
481 5072 1951 -489 606 7883 3475 -1303
482 5096 1962 -494 607 7904 3487 -1311
483 5120 1974 -499 608 7925 3500 -1318
484 5144 1985 -504 609 7946 3513 -1326
485 5168 1997 -510 610 7967 3526 -1334
127
486 5192 2009 -515 611 7988 3539 -1342
487 5216 2020 -520 612 8009 3551 -1350
488 5240 2032 -525 613 8030 3564 -1358
489 5264 2044 -530 614 8051 3577 -1366
490 5288 2055 -536 615 8072 3590 -1374
491 5312 2067 -541 616 8093 3603 -1383
492 5335 2079 -546 617 8114 3616 -1391
493 5359 2090 -552 618 8135 3629 -1399
494 5383 2102 -557 619 8156 3642 -1407
495 5407 2114 -562 620 8177 3655 -1415
496 5430 2126 -568 621 8198 3667 -1423
497 5454 2137 -573 622 8219 3680 -1431
498 5478 2149 -579 623 8239 3693 -1440
499 5501 2161 -584 62315 8242 3695 -1441
128
Appendix F
Table F1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in solid
state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 1063 334 -017
299 029 009 000 331 1096 345 -018
300 063 019 000 332 1128 356 -019
301 097 029 000 333 1161 366 -020
302 131 039 000 334 1193 377 -021
303 165 050 000 335 1225 388 -022
304 199 060 -001 336 1258 399 -024
305 233 070 -001 337 1290 410 -025
306 267 081 -001 338 1322 421 -026
307 300 091 -001 339 1355 432 -028
308 334 101 -002 340 1387 443 -029
309 368 112 -002 341 1419 454 -030
310 401 122 -002 342 1451 464 -032
311 435 133 -003 343 1483 475 -033
312 468 143 -003 344 1515 486 -035
313 502 153 -004 345 1547 497 -036
314 535 164 -004 346 1578 508 -038
315 569 174 -005 347 1610 519 -039
316 602 185 -005 348 1642 531 -041
317 635 196 -006 349 1674 542 -043
318 668 206 -006 350 1705 553 -044
319 702 217 -007 351 1737 564 -046
320 735 227 -008 352 1769 575 -048
321 768 238 -009 353 1800 586 -049
322 801 248 -009 354 1832 597 -051
323 834 259 -010 355 1863 608 -053
324 867 270 -011 356 1894 619 -055
325 900 280 -012 357 1926 631 -057
326 932 291 -013 358 1957 642 -059
327 965 302 -014 359 1988 653 -061
328 998 313 -015 35915 1993 655 -061
329 1030 323 -016
129
Table F2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in liquid
state (37515-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2691 926 -083 500 6111 2416 -640
376 2717 936 -085 501 6136 2428 -646
377 2747 948 -088 502 6161 2440 -652
378 2778 959 -091 503 6185 2453 -658
379 2808 971 -094 504 6210 2465 -665
380 2838 982 -096 505 6235 2478 -671
381 2869 994 -099 506 6259 2490 -677
382 2899 1005 -102 507 6284 2502 -683
383 2929 1017 -105 508 6308 2515 -690
384 2959 1028 -108 509 6333 2527 -696
385 2989 1040 -111 510 6357 2540 -702
386 3019 1051 -114 511 6381 2552 -709
387 3049 1063 -117 512 6406 2565 -715
388 3079 1075 -120 513 6430 2577 -721
389 3109 1086 -123 514 6454 2590 -728
390 3138 1098 -126 515 6479 2602 -734
391 3168 1109 -129 516 6503 2615 -741
392 3198 1121 -133 517 6527 2627 -747
393 3227 1132 -136 518 6551 2640 -754
394 3257 1144 -139 519 6575 2652 -760
395 3286 1156 -142 520 6599 2665 -767
396 3316 1167 -146 521 6624 2677 -774
397 3345 1179 -149 522 6648 2690 -780
398 3374 1191 -152 523 6672 2702 -787
399 3403 1202 -156 524 6696 2715 -794
400 3433 1214 -159 525 6719 2727 -800
401 3462 1226 -163 526 6743 2740 -807
402 3491 1237 -166 527 6767 2753 -814
403 3520 1249 -170 528 6791 2765 -821
404 3549 1261 -173 529 6815 2778 -827
405 3578 1272 -177 530 6839 2790 -834
130
406 3606 1284 -180 531 6862 2803 -841
407 3635 1296 -184 532 6886 2815 -848
408 3664 1307 -187 533 6910 2828 -855
409 3693 1319 -191 534 6933 2841 -862
410 3721 1331 -195 535 6957 2853 -869
411 3750 1343 -199 536 6981 2866 -876
412 3778 1354 -202 537 7004 2879 -883
413 3807 1366 -206 538 7028 2891 -890
414 3835 1378 -210 539 7051 2904 -897
415 3864 1390 -214 540 7075 2917 -904
416 3892 1401 -218 541 7098 2929 -911
417 3920 1413 -222 542 7122 2942 -918
418 3948 1425 -226 543 7145 2955 -925
419 3977 1437 -230 544 7168 2967 -932
420 4005 1449 -234 545 7192 2980 -939
421 4033 1460 -238 546 7215 2993 -947
422 4061 1472 -242 547 7238 3005 -954
423 4089 1484 -246 548 7261 3018 -961
424 4117 1496 -250 549 7285 3031 -968
425 4145 1508 -254 550 7308 3044 -976
426 4172 1519 -258 551 7331 3056 -983
427 4200 1531 -262 552 7354 3069 -990
428 4228 1543 -266 553 7377 3082 -998
429 4256 1555 -271 554 7400 3095 -1005
430 4283 1567 -275 555 7423 3107 -1013
431 4311 1579 -279 556 7446 3120 -1020
432 4338 1591 -284 557 7469 3133 -1027
433 4366 1603 -288 558 7492 3146 -1035
434 4393 1614 -292 559 7515 3159 -1042
435 4421 1626 -297 560 7538 3171 -1050
436 4448 1638 -301 561 7561 3184 -1058
437 4475 1650 -306 562 7584 3197 -1065
438 4503 1662 -310 563 7607 3210 -1073
439 4530 1674 -315 564 7629 3223 -1080
440 4557 1686 -319 565 7652 3235 -1088
441 4584 1698 -324 566 7675 3248 -1096
442 4611 1710 -328 567 7697 3261 -1103
443 4638 1722 -333 568 7720 3274 -1111
444 4665 1734 -338 569 7743 3287 -1119
445 4692 1746 -342 570 7765 3300 -1126
131
446 4719 1758 -347 571 7788 3313 -1134
447 4746 1770 -352 572 7811 3326 -1142
448 4773 1782 -356 573 7833 3338 -1150
449 4800 1794 -361 574 7856 3351 -1158
450 4826 1806 -366 575 7878 3364 -1166
451 4853 1818 -371 576 7901 3377 -1173
452 4880 1830 -376 577 7923 3390 -1181
453 4906 1842 -381 578 7945 3403 -1189
454 4933 1854 -386 579 7968 3416 -1197
455 4959 1866 -391 580 7990 3429 -1205
456 4986 1878 -396 581 8012 3442 -1213
457 5012 1890 -401 582 8035 3455 -1221
458 5039 1902 -406 583 8057 3468 -1229
459 5065 1914 -411 584 8079 3481 -1237
460 5091 1926 -416 585 8101 3494 -1245
461 5118 1938 -421 586 8124 3507 -1254
462 5144 1951 -426 587 8146 3520 -1262
463 5170 1963 -431 588 8168 3533 -1270
464 5196 1975 -436 589 8190 3546 -1278
465 5222 1987 -441 590 8212 3559 -1286
466 5248 1999 -447 591 8234 3572 -1294
467 5274 2011 -452 592 8256 3585 -1303
468 5300 2023 -457 593 8278 3598 -1311
469 5326 2035 -463 594 8300 3611 -1319
470 5352 2048 -468 595 8322 3624 -1328
471 5378 2060 -473 596 8344 3637 -1336
472 5404 2072 -479 597 8366 3650 -1344
473 5430 2084 -484 598 8388 3663 -1353
474 5455 2096 -490 599 8410 3676 -1361
475 5481 2108 -495 600 8432 3690 -1369
476 5507 2121 -500 601 8454 3703 -1378
477 5532 2133 -506 602 8475 3716 -1386
478 5558 2145 -512 603 8497 3729 -1395
479 5583 2157 -517 604 8519 3742 -1403
480 5609 2170 -523 605 8541 3755 -1412
481 5634 2182 -528 606 8562 3768 -1420
482 5660 2194 -534 607 8584 3781 -1429
483 5685 2206 -540 608 8606 3795 -1438
484 5710 2219 -545 609 8627 3808 -1446
485 5736 2231 -551 610 8649 3821 -1455
132
486 5761 2243 -557 611 8670 3834 -1464
487 5786 2255 -563 612 8692 3847 -1472
488 5812 2268 -568 613 8713 3860 -1481
489 5837 2280 -574 614 8735 3874 -1490
490 5862 2292 -580 615 8756 3887 -1498
491 5887 2305 -586 616 8778 3900 -1507
492 5912 2317 -592 617 8799 3913 -1516
493 5937 2329 -598 618 8821 3926 -1525
494 5962 2342 -604 619 8842 3940 -1534
495 5987 2354 -610 620 8864 3953 -1542
496 6012 2366 -616 621 8885 3966 -1551
497 6037 2379 -622 622 8906 3979 -1560
498 6062 2391 -628 623 8928 3993 -1569
499 6086 2403 -634 62315 8931 3995 -1570
133
Appendix G
Table G1 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid I state (29815-33715K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 319 578 162 -004
299 024 000 000 320 606 170 -005
300 052 000 000 321 633 179 -005
301 080 007 000 322 660 188 -006
302 108 016 000 323 688 197 -007
303 136 024 000 324 715 205 -007
304 164 032 000 325 742 214 -008
305 192 041 000 326 769 223 -009
306 219 049 000 327 796 232 -009
307 247 058 000 328 823 241 -010
308 275 067 -001 329 851 250 -011
309 303 075 -001 330 878 259 -011
310 330 084 -001 331 905 268 -012
311 358 092 -001 332 932 277 -013
312 386 101 -002 333 959 285 -014
313 413 109 -002 334 985 294 -015
314 441 118 -002 335 1012 303 -016
315 468 127 -003 336 1039 312 -017
316 496 135 -003 337 1066 321 -018
317 523 144 -003 33715 1070 331 -019
318 551 153 -004
Table G2 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid II state (36115-36415K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36115 2433 825 -054
134
362 2454 832 -056
363 2478 841 -059
364 2503 850 -061
36415 2506 851 -062
Table G3 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
liquid state (41115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
41115 3833 1366 -210 518 6604 2649 -772
412 3857 1376 -213 519 6628 2661 -778
413 3885 1387 -217 520 6652 2674 -785
414 3913 1399 -221 521 6675 2686 -792
415 3941 1411 -225 522 6699 2699 -798
416 3969 1422 -229 523 6723 2711 -805
417 3997 1434 -233 524 6747 2723 -812
418 4025 1446 -237 525 6770 2736 -819
419 4053 1457 -241 526 6794 2748 -825
420 4081 1469 -245 527 6818 2761 -832
421 4109 1481 -249 528 6841 2773 -839
422 4137 1493 -253 529 6865 2786 -846
423 4165 1504 -257 530 6888 2798 -853
424 4192 1516 -262 531 6912 2810 -860
425 4220 1528 -266 532 6935 2823 -867
426 4248 1539 -270 533 6959 2835 -873
427 4275 1551 -274 534 6982 2848 -880
428 4303 1563 -279 535 7005 2860 -887
429 4330 1575 -283 536 7029 2873 -894
430 4358 1587 -287 537 7052 2885 -902
431 4385 1598 -292 538 7075 2898 -909
432 4412 1610 -296 539 7098 2910 -916
433 4439 1622 -300 540 7122 2923 -923
434 4467 1634 -305 541 7145 2935 -930
135
435 4494 1646 -309 542 7168 2948 -937
436 4521 1657 -314 543 7191 2960 -944
437 4548 1669 -318 544 7214 2973 -951
438 4575 1681 -323 545 7237 2986 -959
439 4602 1693 -328 546 7260 2998 -966
440 4629 1705 -332 547 7283 3011 -973
441 4656 1716 -337 548 7306 3023 -980
442 4683 1728 -341 549 7329 3036 -988
443 4710 1740 -346 550 7352 3048 -995
444 4736 1752 -351 551 7375 3061 -1003
445 4763 1764 -356 552 7398 3074 -1010
446 4790 1776 -360 553 7420 3086 -1017
447 4816 1788 -365 554 7443 3099 -1025
448 4843 1800 -370 555 7466 3111 -1032
449 4869 1812 -375 556 7489 3124 -1040
450 4896 1823 -380 557 7511 3137 -1047
451 4922 1835 -385 558 7534 3149 -1055
452 4949 1847 -390 559 7557 3162 -1062
453 4975 1859 -395 560 7579 3175 -1070
454 5002 1871 -400 561 7602 3187 -1077
455 5028 1883 -405 562 7625 3200 -1085
456 5054 1895 -410 563 7647 3213 -1093
457 5080 1907 -415 564 7670 3225 -1100
458 5106 1919 -420 565 7692 3238 -1108
459 5132 1931 -425 566 7714 3251 -1116
460 5159 1943 -430 567 7737 3263 -1123
461 5185 1955 -435 568 7759 3276 -1131
462 5211 1967 -440 569 7782 3289 -1139
463 5236 1979 -446 570 7804 3302 -1147
464 5262 1991 -451 571 7826 3314 -1155
465 5288 2003 -456 572 7849 3327 -1162
466 5314 2015 -461 573 7871 3340 -1170
467 5340 2027 -467 574 7893 3352 -1178
468 5366 2039 -472 575 7915 3365 -1186
469 5391 2051 -478 576 7937 3378 -1194
470 5417 2063 -483 577 7960 3391 -1202
471 5442 2075 -488 578 7982 3404 -1210
472 5468 2087 -494 579 8004 3416 -1218
473 5494 2099 -499 580 8026 3429 -1226
474 5519 2111 -505 581 8048 3442 -1234
136
475 5545 2123 -510 582 8070 3455 -1242
476 5570 2135 -516 583 8092 3468 -1250
477 5595 2147 -521 584 8114 3480 -1258
478 5621 2160 -527 585 8136 3493 -1266
479 5646 2172 -533 586 8158 3506 -1274
480 5671 2184 -538 587 8180 3519 -1283
481 5696 2196 -544 588 8201 3532 -1291
482 5722 2208 -550 589 8223 3545 -1299
483 5747 2220 -555 590 8245 3557 -1307
484 5772 2232 -561 591 8267 3570 -1315
485 5797 2244 -567 592 8289 3583 -1324
486 5822 2257 -573 593 8310 3596 -1332
487 5847 2269 -579 594 8332 3609 -1340
488 5872 2281 -585 595 8354 3622 -1349
489 5897 2293 -590 596 8375 3635 -1357
490 5922 2305 -596 597 8397 3648 -1365
491 5947 2317 -602 598 8419 3660 -1374
492 5971 2330 -608 599 8440 3673 -1382
493 5996 2342 -614 600 8462 3686 -1391
494 6021 2354 -620 601 8483 3699 -1399
495 6046 2366 -626 602 8505 3712 -1408
496 6070 2379 -632 603 8526 3725 -1416
497 6095 2391 -638 604 8548 3738 -1425
498 6119 2403 -645 605 8569 3751 -1433
499 6144 2415 -651 606 8591 3764 -1442
500 6169 2427 -657 607 8612 3777 -1451
501 6193 2440 -663 608 8633 3790 -1459
502 6217 2452 -669 609 8655 3803 -1468
503 6242 2464 -675 610 8676 3816 -1476
504 6266 2477 -682 611 8697 3829 -1485
505 6291 2489 -688 612 8719 3842 -1494
506 6315 2501 -694 613 8740 3855 -1503
507 6339 2513 -701 614 8761 3868 -1511
508 6363 2526 -707 615 8782 3881 -1520
509 6388 2538 -713 616 8803 3894 -1529
510 6412 2550 -720 617 8825 3907 -1538
511 6436 2563 -726 618 8846 3920 -1547
512 6460 2575 -733 619 8867 3933 -1555
513 6484 2587 -739 620 8888 3946 -1564
514 6508 2600 -746 621 8909 3959 -1573
137
515 6532 2612 -752 622 8930 3972 -1582
516 6556 2624 -759 623 8951 3985 -1591
517 6580 2637 -765 62315 8954 3987 -1592
138
Appendix H
Table H1 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid I
state (29815-35415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 768 241 -011
299 023 007 000 328 794 249 -011
300 050 015 000 329 820 258 -012
301 077 023 000 330 846 266 -013
302 104 031 000 331 872 275 -014
303 131 039 000 332 898 284 -015
304 158 048 000 333 924 292 -016
305 185 056 -001 334 950 301 -016
306 212 064 -001 335 976 310 -017
307 239 072 -001 336 1002 318 -018
308 265 081 -001 337 1028 327 -019
309 292 089 -001 338 1053 336 -020
310 319 097 -002 339 1079 344 -021
311 345 105 -002 340 1105 353 -022
312 372 114 -002 341 1130 362 -024
313 399 122 -003 342 1156 371 -025
314 425 130 -003 343 1182 379 -026
315 452 139 -004 344 1207 388 -027
316 478 147 -004 345 1233 397 -028
317 505 156 -004 346 1258 406 -029
318 531 164 -005 347 1284 415 -031
319 558 172 -005 348 1309 424 -032
320 584 181 -006 349 1335 433 -033
321 611 189 -007 350 1360 441 -035
322 637 198 -007 351 1385 450 -036
323 663 206 -008 352 1411 459 -037
324 689 215 -008 353 1436 468 -039
325 716 223 -009 354 1461 477 -040
326 742 232 -010 35415 1465 478 -040
139
Table H2 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid 2
state (36215-37315K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36215 2387 777 -046
363 2408 809 -055
364 2432 817 -057
365 2457 826 -060
366 2481 835 -062
367 2506 843 -065
368 2530 852 -067
369 2555 861 -070
370 2579 870 -072
371 2604 879 -075
372 2628 888 -077
373 2653 898 -080
37315 2657 907 -083
Table H3 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in liquid
state (37915-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37915 2966 1025 -100 502 6174 2432 -667
380 2991 1034 -102 503 6198 2444 -674
381 3020 1045 -105 504 6222 2456 -680
382 3048 1056 -108 505 6246 2468 -686
383 3077 1067 -112 506 6270 2480 -692
384 3105 1078 -115 507 6294 2492 -699
385 3134 1089 -118 508 6317 2504 -705
386 3162 1100 -121 509 6341 2516 -711
387 3191 1111 -124 510 6365 2528 -718
140
388 3219 1122 -127 511 6388 2541 -724
389 3247 1133 -130 512 6412 2553 -730
390 3275 1144 -134 513 6436 2565 -737
391 3304 1155 -137 514 6459 2577 -743
392 3332 1166 -140 515 6483 2589 -750
393 3360 1177 -144 516 6506 2601 -756
394 3388 1188 -147 517 6530 2613 -763
395 3416 1199 -150 518 6553 2625 -769
396 3444 1210 -154 519 6577 2638 -776
397 3472 1221 -157 520 6600 2650 -782
398 3500 1232 -161 521 6624 2662 -789
399 3527 1243 -164 522 6647 2674 -796
400 3555 1254 -168 523 6670 2686 -802
401 3583 1265 -171 524 6694 2698 -809
402 3611 1276 -175 525 6717 2711 -816
403 3638 1287 -179 526 6740 2723 -822
404 3666 1299 -182 527 6763 2735 -829
405 3693 1310 -186 528 6786 2747 -836
406 3721 1321 -190 529 6810 2760 -843
407 3748 1332 -193 530 6833 2772 -850
408 3776 1343 -197 531 6856 2784 -856
409 3803 1354 -201 532 6879 2796 -863
410 3830 1366 -205 533 6902 2809 -870
411 3857 1377 -209 534 6925 2821 -877
412 3885 1388 -213 535 6948 2833 -884
413 3912 1399 -216 536 6971 2845 -891
414 3939 1410 -220 537 6994 2858 -898
415 3966 1422 -224 538 7017 2870 -905
416 3993 1433 -228 539 7040 2882 -912
417 4020 1444 -232 540 7063 2895 -919
418 4047 1455 -236 541 7086 2907 -926
419 4074 1467 -240 542 7108 2919 -933
420 4101 1478 -245 543 7131 2932 -940
421 4128 1489 -249 544 7154 2944 -947
422 4154 1500 -253 545 7177 2957 -955
423 4181 1512 -257 546 7199 2969 -962
424 4208 1523 -261 547 7222 2981 -969
425 4234 1534 -265 548 7245 2994 -976
426 4261 1546 -270 549 7267 3006 -984
427 4288 1557 -274 550 7290 3019 -991
141
428 4314 1568 -278 551 7313 3031 -998
429 4341 1580 -282 552 7335 3044 -1005
430 4367 1591 -287 553 7358 3056 -1013
431 4393 1602 -291 554 7380 3068 -1020
432 4420 1614 -296 555 7403 3081 -1028
433 4446 1625 -300 556 7425 3093 -1035
434 4472 1636 -305 557 7448 3106 -1042
435 4499 1648 -309 558 7470 3118 -1050
436 4525 1659 -314 559 7492 3131 -1057
437 4551 1671 -318 560 7515 3143 -1065
438 4577 1682 -323 561 7537 3156 -1072
439 4603 1694 -327 562 7560 3169 -1080
440 4629 1705 -332 563 7582 3181 -1087
441 4655 1716 -336 564 7604 3194 -1095
442 4681 1728 -341 565 7626 3206 -1103
443 4707 1739 -346 566 7649 3219 -1110
444 4733 1751 -351 567 7671 3231 -1118
445 4759 1762 -355 568 7693 3244 -1126
446 4785 1774 -360 569 7715 3257 -1133
447 4810 1785 -365 570 7737 3269 -1141
448 4836 1797 -370 571 7759 3282 -1149
449 4862 1808 -375 572 7782 3294 -1157
450 4888 1820 -379 573 7804 3307 -1164
451 4913 1832 -384 574 7826 3320 -1172
452 4939 1843 -389 575 7848 3332 -1180
453 4964 1855 -394 576 7870 3345 -1188
454 4990 1866 -399 577 7892 3358 -1196
455 5015 1878 -404 578 7914 3370 -1204
456 5041 1889 -409 579 7936 3383 -1212
457 5066 1901 -414 580 7957 3396 -1220
458 5092 1913 -419 581 7979 3408 -1228
459 5117 1924 -424 582 8001 3421 -1236
460 5142 1936 -430 583 8023 3434 -1244
461 5167 1947 -435 584 8045 3447 -1252
462 5193 1959 -440 585 8067 3459 -1260
463 5218 1971 -445 586 8088 3472 -1268
464 5243 1982 -450 587 8110 3485 -1276
465 5268 1994 -456 588 8132 3498 -1284
466 5293 2006 -461 589 8154 3510 -1292
467 5318 2017 -466 590 8175 3523 -1300
142
468 5343 2029 -472 591 8197 3536 -1308
469 5368 2041 -477 592 8219 3549 -1317
470 5393 2053 -482 593 8240 3562 -1325
471 5418 2064 -488 594 8262 3574 -1333
472 5443 2076 -493 595 8283 3587 -1341
473 5468 2088 -499 596 8305 3600 -1350
474 5493 2100 -504 597 8327 3613 -1358
475 5517 2111 -510 598 8348 3626 -1366
476 5542 2123 -515 599 8370 3639 -1375
477 5567 2135 -521 600 8391 3652 -1383
478 5592 2147 -526 601 8413 3664 -1391
479 5616 2158 -532 602 8434 3677 -1400
480 5641 2170 -537 603 8455 3690 -1408
481 5665 2182 -543 604 8477 3703 -1417
482 5690 2194 -549 605 8498 3716 -1425
483 5715 2206 -554 606 8520 3729 -1434
484 5739 2218 -560 607 8541 3742 -1442
485 5763 2229 -566 608 8562 3755 -1451
486 5788 2241 -572 609 8583 3768 -1459
487 5812 2253 -578 610 8605 3781 -1468
488 5837 2265 -583 611 8626 3794 -1477
489 5861 2277 -589 612 8647 3807 -1485
490 5885 2289 -595 613 8668 3820 -1494
491 5910 2301 -601 614 8690 3833 -1503
492 5934 2313 -607 615 8711 3846 -1511
493 5958 2324 -613 616 8732 3859 -1520
494 5982 2336 -619 617 8753 3872 -1529
495 6006 2348 -625 618 8774 3885 -1538
496 6030 2360 -631 619 8795 3898 -1546
497 6055 2372 -637 620 8816 3911 -1555
498 6079 2384 -643 621 8837 3924 -1564
499 6103 2396 -649 622 8858 3937 -1573
500 6127 2408 -655 623 8879 3950 -1582
501 6151 2420 -661 62315 8883 3952 -1583
143
Appendix I
Table I1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in solid state (29815-35315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 1171 366 -017
299 035 010 000 328 1211 379 -018
300 076 023 000 329 1250 392 -019
301 117 035 000 330 1290 405 -021
302 158 048 000 331 1330 418 -022
303 199 060 000 332 1369 431 -023
304 240 072 -001 333 1409 444 -025
305 281 085 -001 334 1448 458 -026
306 322 097 -001 335 1488 471 -028
307 363 110 -002 336 1527 484 -029
308 404 122 -002 337 1566 497 -031
309 445 135 -002 338 1605 510 -032
310 486 148 -003 339 1644 524 -034
311 526 160 -003 340 1683 537 -036
312 567 173 -004 341 1722 550 -037
313 608 186 -005 342 1761 563 -039
314 648 198 -005 343 1800 577 -041
315 689 211 -006 344 1839 590 -043
316 729 224 -007 345 1877 603 -044
317 770 237 -007 346 1916 617 -046
318 810 250 -008 347 1955 630 -048
319 850 262 -009 348 1993 643 -050
320 891 275 -010 349 2031 657 -052
321 931 288 -011 350 2070 670 -054
322 971 301 -012 351 2108 683 -056
323 1011 314 -013 352 2146 697 -059
324 1051 327 -014 353 2184 710 -061
325 1091 340 -015 35315 2190 712 -061
326 1131 353 -016
144
Table I2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in liquid state (39115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
39115 4413 1056 -191 508 8890 3521 -978
392 4450 1535 -195 509 8924 3538 -986
393 4492 1549 -200 510 8959 3556 -995
394 4535 1566 -204 511 8993 3574 -1004
395 4577 1583 -209 512 9027 3591 -1013
396 4620 1599 -213 513 9062 3609 -1022
397 4662 1616 -218 514 9096 3626 -1031
398 4704 1633 -223 515 9130 3644 -1041
399 4746 1650 -227 516 9164 3661 -1050
400 4789 1666 -232 517 9198 3679 -1059
401 4831 1683 -237 518 9232 3697 -1068
402 4872 1700 -242 519 9266 3714 -1077
403 4914 1717 -247 520 9300 3732 -1087
404 4956 1734 -252 521 9334 3750 -1096
405 4997 1751 -257 522 9368 3767 -1105
406 5039 1767 -262 523 9402 3785 -1115
407 5080 1784 -267 524 9435 3802 -1124
408 5122 1801 -272 525 9469 3820 -1134
409 5163 1818 -277 526 9503 3838 -1143
410 5204 1835 -282 527 9536 3855 -1152
411 5245 1852 -287 528 9570 3873 -1162
412 5286 1869 -293 529 9603 3891 -1172
413 5327 1885 -298 530 9637 3908 -1181
414 5368 1902 -303 531 9670 3926 -1191
415 5409 1919 -309 532 9703 3944 -1201
416 5450 1936 -314 533 9737 3962 -1210
417 5490 1953 -320 534 9770 3979 -1220
418 5531 1970 -325 535 9803 3997 -1230
419 5571 1987 -331 536 9836 4015 -1240
420 5612 2004 -336 537 9869 4032 -1249
421 5652 2021 -342 538 9902 4050 -1259
145
422 5692 2038 -347 539 9935 4068 -1269
423 5732 2055 -353 540 9968 4086 -1279
424 5772 2072 -359 541 10001 4104 -1289
425 5812 2089 -365 542 10034 4121 -1299
426 5852 2106 -371 543 10066 4139 -1309
427 5892 2123 -376 544 10099 4157 -1319
428 5932 2140 -382 545 10132 4175 -1329
429 5971 2157 -388 546 10165 4192 -1340
430 6011 2174 -394 547 10197 4210 -1350
431 6051 2191 -400 548 10230 4228 -1360
432 6090 2208 -406 549 10262 4246 -1370
433 6129 2225 -412 550 10295 4264 -1380
434 6169 2242 -419 551 10327 4282 -1391
435 6208 2259 -425 552 10359 4299 -1401
436 6247 2276 -431 553 10392 4317 -1411
437 6286 2293 -437 554 10424 4335 -1422
438 6325 2310 -444 555 10456 4353 -1432
439 6364 2327 -450 556 10488 4371 -1443
440 6403 2344 -456 557 10520 4389 -1453
441 6442 2361 -463 558 10553 4407 -1464
442 6480 2378 -469 559 10585 4424 -1474
443 6519 2395 -476 560 10617 4442 -1485
444 6557 2412 -482 561 10648 4460 -1496
445 6596 2429 -489 562 10680 4478 -1506
446 6634 2446 -495 563 10712 4496 -1517
447 6673 2464 -502 564 10744 4514 -1528
448 6711 2481 -509 565 10776 4532 -1538
449 6749 2498 -515 566 10808 4550 -1549
450 6787 2515 -522 567 10839 4568 -1560
451 6825 2532 -529 568 10871 4586 -1571
452 6863 2549 -536 569 10902 4604 -1582
453 6901 2566 -543 570 10934 4622 -1593
454 6939 2584 -550 571 10965 4640 -1604
455 6977 2601 -557 572 10997 4658 -1615
456 7015 2618 -564 573 11028 4676 -1626
457 7052 2635 -571 574 11060 4694 -1637
458 7090 2652 -578 575 11091 4712 -1648
459 7128 2670 -585 576 11122 4730 -1659
460 7165 2687 -592 577 11154 4748 -1670
461 7202 2704 -599 578 11185 4766 -1681
146
462 7240 2721 -606 579 11216 4784 -1692
463 7277 2738 -614 580 11247 4802 -1704
464 7314 2756 -621 581 11278 4820 -1715
465 7351 2773 -628 582 11309 4838 -1726
466 7388 2790 -636 583 11340 4856 -1737
467 7425 2807 -643 584 11371 4874 -1749
468 7462 2825 -650 585 11402 4892 -1760
469 7499 2842 -658 586 11433 4910 -1772
470 7536 2859 -665 587 11464 4928 -1783
471 7573 2877 -673 588 11495 4946 -1794
472 7609 2894 -680 589 11525 4964 -1806
473 7646 2911 -688 590 11556 4982 -1817
474 7682 2928 -696 591 11587 5001 -1829
475 7719 2946 -703 592 11617 5019 -1841
476 7755 2963 -711 593 11648 5037 -1852
477 7792 2980 -719 594 11678 5055 -1864
478 7828 2998 -727 595 11709 5073 -1876
479 7864 3015 -735 596 11739 5091 -1887
480 7900 3032 -742 597 11770 5109 -1899
481 7937 3050 -750 598 11800 5128 -1911
482 7973 3067 -758 599 11831 5146 -1923
483 8009 3084 -766 600 11861 5164 -1935
484 8045 3102 -774 601 11891 5182 -1946
485 8080 3119 -782 602 11921 5200 -1958
486 8116 3137 -791 603 11952 5218 -1970
487 8152 3154 -799 604 11982 5237 -1982
488 8188 3171 -807 605 12012 5255 -1994
489 8223 3189 -815 606 12042 5273 -2006
490 8259 3206 -823 607 12072 5291 -2018
491 8294 3224 -832 608 12102 5309 -2030
492 8330 3241 -840 609 12132 5328 -2042
493 8365 3259 -848 610 12162 5346 -2055
494 8401 3276 -857 611 12192 5364 -2067
495 8436 3293 -865 612 12222 5382 -2079
496 8471 3311 -873 613 12252 5401 -2091
497 8506 3328 -882 614 12281 5419 -2103
498 8542 3346 -890 615 12311 5437 -2116
499 8577 3363 -899 616 12341 5456 -2128
500 8612 3381 -908 617 12370 5474 -2140
501 8647 3398 -916 618 12400 5492 -2153
147
502 8681 3416 -925 619 12430 5510 -2165
503 8716 3433 -934 620 12459 5529 -2178
504 8751 3451 -942 621 12489 5547 -2190
505 8786 3468 -951 622 12518 5565 -2203
506 8820 3486 -960 623 12548 5584 -2215
507 8855 3503 -969 62315 12552 5602 -2217
vi
CHAPTER 5 EXPERIMENTAL PROCEDURE 30
51 Melting point determination of molten salt mixtures 30
511 Materials 30
512 Apparatus and Procedure 30
52 Heat Capacity determination of molten salt mixtures 32
53 Density determination of molten salt mixtures 33
CHAPTER 6 RESULT AND DISCUSSION 34
61 Melting point determination 34
611 DSC equipment calibration 34
612 Results 35
613 Discussion 41
62 Heat capacity determination 51
621 Heat capacity calibration 51
622 Results 52
623 Thermodynamic properties 55
624 Discussion of Gibbs energy change for molten salts 84
63 Density determination 86
vii
631 Density calibration 86
632 Results and discussions 82
64 Thermal energy storage density of molten salts 90
CHAPTER 7 CONCLUSION 94
REFERENCES 96
APPENDIX 104
APPENDIX A 104
APPENDIX B 109
APPENDIX C 114
APPENDIX D 118
APPENDIX E 123
APPENDIX F 128
APPENDIX G 133
APPENDIX H 138
APPENDIX I 143
viii
LIST OF TABLES
21 Melting point of various nitrate salt systems 12
22 Melting point of various carbonate salt systems 13
23 Melting point of various fluoridechloride salt systems 14
24 Melting point of various hydroixde salt systems 15
25 Density coefficients A and B of nitrate salts 16
26 Density coefficients A and B of carbonate salts 17
27 Density coefficients A and B of chloridefluoride salts 17
28 Density coefficients A and B of molten salt mixture with hydroxide salts 18
29 Heat capacity of alkali nitrate salt at 500oC 19
210 Heat capacity of alkali carbonate salt at 500oC 19
211 Heat capacity of fluoridechloride salt at 500oC 20
212 Heat capacity of hydroxide salt at 500oC 21
41 Calculated composition and melting point for multi-component systems 29
61 Calibration data of melting points with different samples 35
62 DSC results of melting point transition point and change of enthalpy 41
ix
63 Fusion and solid phase transition temperature for individual salts 42
64 Melting points of candidate systems as function of temperatures 51
65 Calibration data of heat capacities with different samples 52
66 Heat capacity of selected new TES molten salt mixtures 54
67 Change of Gibbs energy values at 62315K for molten salt systems 85
68 Calibration of density measurements with different pure nitrate salts 86
69 Coefficient of A and B for density determination of salt 1 to salt 9 87
610 Extrapolated value of density and heat capacity at 500oC of salt 1 to salt 9 91
611 Energy density of salt 1 to salt 9 compare to solar salt 92
612 Gravimetric storage densities for solar salt and new molten salts 93
x
LIST OF FIGURES
11 Theoretical and engineering energy conversion efficiency as function of temperature 6
12 Gravimetric storage density for different energy storage systems
as function of temperature 8
51 Photography of set-up for DSC equipment 31
61 Melting point calibration with indium sample 34
62 Melting point calibration with KNO3 sample 35
63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt 36
64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt 37
65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt 37
66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt 38
67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt 38
68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt 39
69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt 39
610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt 40
611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN Salt 40
612 DSC plot of 698wt KNO3 -302wt NaNO2 binary system 43
xi
613 DSC plot of 270wt NaNO3-730wt KNO3 binary system 45
614 DSC plot of 458wtLiNO3-542wtKNO3 binary system 45
615 DSC plot of 460wt NaNO3-540wt KNO3 binary system 46
616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 20oCmin heating rate 47
616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 5oCmin heating rate 48
617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 5oCmin heating rate 49
617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 20oCmin heating rate 49
618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system
as function of temperature 53
619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K 54
620 Change of Gibbs energy as function of temperature for molten salt systems 85
621 The densities of the salt 1 to salt 5 as function of temperature 87
622 The densities of the salt 6 to salt 9 as function of temperature 89
623 Densities of the salt 1 salt 2 as function of temperature compared to
the equimolar NaNO3-KNO3 binary system and pure KNO3 90
624 Gravimetric storage density comparison of different energy storage
xii
systems as function of temperature 93
1
CHAPTER 1
INTRODUCTION
Renewable energy sources such as wind solar water power geothermal and biomass are
playing more and more significant role in our energy supply Because the cheap cost and infinite
amount of energy storage inside the resource solar energy is emphasized since 20th
century and
viewed as promising alternative method to satisfy the large energy consumption every day in the
world reduce the emission of carbon and strengthen the economy
The wind energy was used as a clean energy to generate electricity back to late 19th
century
However this renewable energy source was not emphasized due to the cheap price of fossil fuel
The re-emergence happened in mid 1950s when the amount of traditional energy source was
found apparently decrease The development of wind energy usage continued and in 1990 the
first mega-watt wind turbine was launched which was viewed as a symbol of shift to large scale
wind energy utilization [1-2] The modern application of wind energy mainly relies on wind
turbine On the basis of aerodynamic wind turbine generates certain net positive torque on
rotating shaft and then converts the mechanical power to electrical power As an electrical power
generator wind turbine is connected to some electrical network to transport the electricity to
battery charging utilities residential power systems and large scale energy consuming systems
In general most of wind turbines are small scale and can only generate 10KW electrical power
Only few of the wind turbine systems operate with capacity as large as 5MW Although the
usage of wind energy can reduce the emission of carbon oxide the noise pollution and high cost
2
limit its large scale application Since the wind is not transportable the electrical energy can only
be generated where the wind blows which also decrease the flexibility of wind energy
Water power is another term of alternative power supply and it was used for irrigation
operating machines like watermill even before the development of electrical power The modern
application of water power is to generate electricity by using the gravitational force of falling or
flowing water These days there are various ways for the water power application The most
traditional method is to store the water in dam and generate electricity by converting the
potential energy pump storage is a different way to utilize water power and can change its
output depending on the energy demand by moving water between reservoirs at different
elevations In the low energy demand period excess energy is used to lift water to the higher
level while in the peak period of energy demand the water is released back to the lower
elevation through water turbine Water power can also be converted by taking advantage of
naturally raise and fall of tide to satisfy the demand of electrical energy consumption [3]
Although the usage of water power can reduce the emission of carbon dioxide and cost it will
destroy the ecosystem because of the large land required for construction There will be methane
emission from the reservoir the potential failure hazard of dam is also a fatal issue and flow
shortage caused by drought may also create serious problem As result of that water power
technique is not a long-term alternative choice
Geothermal energy is the energy form generated inside the earth At the very beginning of
the planet formation a large amount of thermal energy was stored from the radioactive decay of
minerals volcanic activity and solar energy absorption Because of the temperature difference
3
between the core and the surface of planet the thermal energy stored inside the earth is driven to
the outer surface in the form of heat This form of renewable energy source can be applied to
generate electrical power and heat for industrial space and agricultural applications
Theoretically the deposited amount of geothermal energy is adequate to supply the energy
consumption in the world However most of the geothermal energy is stored deeply near the
core of the earth the deep drilling and exploration of geothermal energy is very expensive and
limits the large-scale use of this renewable energy source [4]
Biomass is a renewable energy source used to generate heat or electricity with living or
recently living organism such as wood waste (hydrogen) gas and alcohol fuels The biomass
energy can be converted to electrical energy by thermal method such as combustion pyrolysis
and gasification Several specific chemical processes may also be able to convert the biomass
energy to other forms The main problem arise from application of biomass is air pollution which
contains carbon monoxide NOx (nitrogen oxides) VOCs (volatile organic compounds)
particulates and other pollutants And the level of air pollution to some extent is even above that
of traditional fuel resource Some other possible issue like transportation and sink of carbon also
limit the wide usage of this type of alternative energy [5]
Among all the renewable energy sources solar energy is the most suitable alternative
energy for our future life It is clean cheap abundant without any noise air pollution no
transportation issue and easy to be obtained anywhere in the earth Inside the core of the Sun
hydrogen fuses into helium with a rate of 7times1011
kgs and generates very powerful nucleation
power This type of nucleation explosion creates ultra high temperature in the core of the Sun
4
which reaches approximately 16 million K degrees Although the Sun is not perfectly black body
it still radiates abundant power with the energy density as 16times107 wattsm
2 [6-7] Because of the
enough amount of hydrogen underneath the surface of the Sun the radiation given arise of from
the nucleation explosion can continue at least 5 million years with the same rate and strength
The energy reaching the earth is vastly reduced mainly caused by the absorption and spreading
of the radiation It is easily to understand that there are numerous amorphous objects all around
the entire universe which can absorb certain portion of the radiation for the Sun Moreover the
light generated from the spherical object such as the Sun fills all the available space between the
origin to the destination Even though the energy will not be lost in the travelling process due to
the long distance between the Sun to the earth the surface area of the sphere which is formed
with the Sun as center and the distance as radius is much larger than that of the earth As the
result of that only 1340Wm2 finally reaches the upmost surface of the earth Even though the
final amount of the received solar energy is very small compared to that is initially radiated from
the Sun the average daily solar radiation falling on one area in the continental United States is
equivalent in total energy content to 11 barrels of oil In summary the solar energy itself is
relatively unlimited useful clean and almost unexploited energy and definitely can behave as
the promising mean for the future energy supply [8]
There are several different methods to take advantage of the solar energy and all the
methods can be distinguished into three group solar parabolic trough solar tower and solar dish
Parabolic trough is constructed by silver coated parabolic mirror and there is a Dewar tube going
through the length of the mirror and set on the focal point all the radiation is concentrated on the
tube and transfer by heat transfer fluid to the thermal energy storage unit Solar tower are used to
5
capture solar energy with thousands of mirrors and focus the concentrated sunlight to the top of
the tower which is located in the middle of the heliostats The thermal energy storage medium
within the tower was heated to high temperature and transferred to thermal energy storage tank
and eventually sent to steam pump The solar dish is built with a large reflective parabolic dish
which concentrates all the received sunlight to one spot There is normally a receiver located on
the focal point and transform the solar energy to other forms of useful energy The working
upper limit temperature of solar parabolic trough system is the lowest among these three systems
normally its maximum working temperature is within the range from 400-500oC the solar tower
has higher maximum working temperature which ranges from 500-1000oC the solar dish has the
highest working upper limit temperature which reaches 700-1200oC [9]
The energy conversion efficiency is the most concerned parameter in the solar energy
storage application and the theoretical and real engineering efficiency are given in fig 11 as
function of temperature The theoretical conversion efficiency can be up to 80 while in real
application the value is always less than 70 regardless of collectors The actual efficiency
increases with temperature in the whole working temperature As a result of that the thermal
energy storage materials in solar parabolic trough for instance should be able to work stably at
the upper limit temperature of this type of collection system which is 500oC to ensure the highest
efficiency [9 10]
6
Fig 11 Theoretical and engineering energy conversion efficiency as function of
temperature
Solar energy can be stored in three major forms sensible heat latent heat and
thermochemical heat Sensible heat storage was utilized based on the heat capacity and the
change as function of temperature of storage materials in the charging and discharging process
which correspond to the absorbing and withdrawing energy processes respectively The sensible
heat stored from the melting point to the maximum working temperature can be expressed by
equation 1 [9]
[1]
Where m is the mass of storage material Tmp and TH are melting point temperature and high
temperature in the same phase respectively Cp(T) is the heat capacity at different temperature
Because the sensible heat storage materials remain in a single phase in the working temperature
range the charging and discharging processes are completely reversible for unlimited cycles
7
Latent heat storage is operated by absorbing and withdrawing energy in the charging and
discharging processes accompanied with fusion of materials [9] The latent heat collected
throughout the working temperature range can be expressed by equation 2 as following
[2]
Where T is temperature in solid state Tmp is melting point temperature of storage material TH is
the high temperature in liquid state and is enthalpy of fusion
Thermochemical heat storage is based on the heat capacity and its change as function of
temperature accompanied with chemical reaction The thermochemical heat collected throughout
the working temperature range can be expressed by equation 3
[3]
Where TL is the low temperature before the reaction TR is the reaction temperature and
is the enthalpy of chemical reaction Because of the destruction of the chemical bonds
in the reaction process the charging and discharging process cannot be completely reversible
which reduces the stability and recyclability of storage operation [10]
Sensible energy storage method is chosen to ensure the efficient usage of solar energy for
parabolic trough system of which the maximum working temperature ranges from 400-500oC
Different from thermochemical heat storage the sensible heat storage can achieve completely
reversible working condition under unlimited cycles Also fig 12 illustrates that the sensible
heat storage materials mainly work in the working temperature range for parabolic trough system
8
and the gravimetric energy storage densities of sensible heat is higher than that of latent heat
materials [9 -11]
Fig 12 Gravimetric storage density for different energy storage systems as function of
temperature
Various materials are chosen to serve as thermal energy storage fluid for sensible heat
such as water thermal oil ionic liquid and molten salt [12] The properties of different heat
transfer fluid determine the performance of solar energy heating system In these days the
efficiency and cost of output of electrical power mainly relies on the parabolic trough solar
power plant and the thermal storage fluid [12] A large investment cost is needed to dispatch
100MW to 200MW energy by consuming the energy transfer fluids Given by this situation the
development of new thermal storage fluid with higher thermal energy storage density is
paramount to lower the expense for generating energy and a lot of effect has been put on design
of new systems [13-16]
9
Water is commonly used as heat transfer and thermal energy storage fluid in industry
because of its low cost high heat capacity and high thermal conductivity However the
limitation for using this medium is also obvious that the temperature range within which the
liquid state can be assured is too small It is well know that water can only serve as thermal
energy storage liquid above the freezing point 0oC and below the boiling temperature 100
oC In
practical experiment the actual temperature range is even less than 100oC because of the large
amount of weight loss near the boiling temperature due to the high vapor pressure Water is
possible to work above 100oC only if high pressure is also applied to avoid the phase
transformation but the cost will be highly increased Accordingly water is only suitable to work
in low temperature below 100oC
Thermal oils are also being used in the parabolic trough solar power plant and have very
low melting point as low as 12oC [17 18] However the application of the oil for the thermal
energy storage liquid is limited by some disadvantages from the physic-chemical properties The
upper limit for this oil is only 300oC and above that the liquid state cannot be maintained
Moreover the low thermal decomposition temperature low density and low heat capacity result
in limited thermal energy storage capacity Since the working temperature range is so narrow the
rankie cycle efficiency is reduced when using the synthetic oil and the cost for generating power
is considered to be very expensive [19 20]
Ionic liquid is another medium served as thermal energy storage fluid The liquid
temperature range of ionic liquid is large which is one of the main advantages of this type of
material The high heat capacity and density ensure the efficiency of thermal energy storage of
10
ionic liquid What‟s more the excellent chemical stability and little vapor pressure increase the
lifetime [21-24] However as a result of the very serve corrosion problem to the liquid container
and the high cost the usage of ionic liquid is still limited
Considering various relative physic-chemical properties of thermal energy storage system
molten salts have been proposed as a suitable group for a wide temperature range application
They are being emphasized in the solar energy applications because of their low melting point
and high upper limit which can increase the stable working range The high heat capacity
increases the thermal energy storage density of the heat storage system excellent thermal
stability and negligible vapor pressure ensure the steadiness of cyclic repeating in the lifetime
[25] low viscosity strengths the mobility and efficiency of the thermal storage liquid low
utilization cost reduce the investment and protect the economy The liquidus temperature range
of the molten salt varies from 150-600oC combination of various salts can bring the melting
down and further increase the working temperature range Due to these properties molten salts
can be excellent thermal energy storage fluid in the solar power generation system
11
CHAPTER 2
LITERATURE REVIEW
Several physical and thermodynamic properties of thermal energy storage fluid play
significant role in determining the efficiency and performance of solar energy storage systems In
order to evaluate the feasibility of systems the physic-chemical properties of several molten salts
should be reviewed The three determining parameter which directly affect the thermal energy
storage capacity in systems are melting point heat capacity and density
There are large amount of melting point data available in the literature for various molten
salt system in previous literatures while those with melting point less than 120oC is very limited
All the previous study on molten salt system revealed that five group of molten salts are
emphasized and commonly used alkai or alkaline nitrates carbonates sulphates chloride and
hydroxides Although most of the systems have the same group of cation the melting point
varies a lot from one to anther due to the different effect of anions
21 Melting point
The melting points of individual and multi-component nitratenitrite systems are listed in
Table 21[26-31] Among those systems solar salt (NaNO3KNO3 6040) is the thermal energy
storage medium which is currently being used with the freezing point of 221oC [27] Although
the melting point for this system is highest in all the candidate mixtures in this group the lowest
12
combined compound cost makes it widely used in solar energy storage field Another ternary
system HITEC which contains NaNO3 KNO3 and NaNO2 has freezing point of 141 oC [28]
This combination brings the melting point down but the lack of combination of optimum features
limits its further application [29] Some mixtures such as LiNO3-Ca(NO3)2-KNO3 are not often
utilized because they increase the compound cost at the same time of lowering the melting point
to around 120oC [30] moreover the decreased melting point is still high compared to the
organic oil There are also several systems have the melting points less than 100oC or even 60
oC
they are not used in the parabolic trough solar power plant due to the decomposition of some
components during high temperature [31]
Table 21 Melting point of various nitrate salt systems
Compound Melting Point (ordmC)
LiNO3 253
NaNO3 307
KNO3 334
Ca(NO3)2 561
Sr(NO3)2 570
Ba(NO3)2 590
NaNO3-NaNO2 221
NaNO3-NaNO2-KNO3 141
NaNO3-KNO3-CaNO3 133
LiNO3-KNO3-NaNO3 120
KNO3-CaNO3-LiNO3 117
LiNO3-KNO3-NHNO3 92
KNO3-NHNO3-AgNO3 52
The melting points of individual and multi-component carbonate systems are listed in
Table 22 [26 32 33] Different from the nitrate salts the melting points for both the individual
13
and multi-component carbonate systems are on the higher side The lowest melting point is
achieved with lithium sodium and potassium carbonate ternary system whose melting point is
still 277oC higher than that of the nitrate ternary system with the same cations [32] Besides
because of the thermal decomposition issue the choice of component involved in the multi-
component carbonate systems is limited Some salt like CaCO3 doesn‟t have stable form at high
temperature and the lack of multi-component system reduces the chance of the synthesis of low
melting point salt mixtures Even though this group of salt is not thermally stable and the
working temperature range is relatively small it is still viewed as possible candidate working at
high temperature due to its low price
Table 22 Melting point of various carbonate salt systems
Compound Melting Point (ordmC)
Li2CO3 732
Na2CO3 858
K2CO3 900
MgCO3 990
Na2CO3-K2CO3 710
Li2CO3-Na2CO3 496
Li2CO3-K2CO3 488
Li2CO3-K2CO3-Na2CO3 397
Alkali and Alkaline fluoridechloride salts are also selected as one possible choice as the
thermal energy storage fluid and the melting point examined from previous literatures are given
in table 23 [34-38] A lot of study has been done for this group of salt and the melting points
were found in the same range as the carbonate group And for the pure salt metal chloride salts
have lower melting point than metal fluoride ones
14
Table 23 Melting point of various fluoridechloride salt systems
Compound Melting Point (ordmC)
LiF 849
NaF 996
KF 858
LiCl 610
NaCl 801
KCl 771
LiF-KF 493
LiF-NaF 652
LiCl-KF 487
LiF-NaF-KF 454
LiF-NaF-KF-MgF2 449
LiF-KF-BaF2 320
LiF-KF-CsF-RbF 256
Several studies were also conducted to determine the melting point of molten hydroxide
salts and the results are shown in Table24 The data of pure salts and multi-component mixtures
merely in this group were not much determined in the literatures Generally they are mixed with
other groups of anion and form some low melting point salt mixtures [39-42] On the basis of the
previous literature data alkali hydroxide salts and their mixture with salts in other groups have
relatively lower melting point compared with pure carbonate and fluoride chloride group salt
mixtures Most of the melting points given in Table 4 are lower than 300oC sodium potassium
hydroxide binary mixture even reaches the melting point below 200oC Accordingly relatively
large temperature range can be obtained by using hydroxide salt mixtures or adding them as
additive
15
Table 24 Melting point of various hydroixde salt systems
Compound Melting Point (ordmC)
LiOH-LiF 427
NaOH-KOH 170
LiOH-NaOH 213
NaOH-NaNO2 232
NaOH-NaNO3 237
NaOH-NaCl-NaNO3 242
NaOH-NaCl-Na2CO3 282
22 Density
For the solar energy storage system density for the thermal energy storage fluid is also
essential parameter The density is needed for the size calculation as function of temperature and
assessing for the thermal stability of thermoclines Besides density as function of temperature is
used to evaluate the volume change in the process of freezing which contributes to potential
stress
Alkalialkaline nitrate salts were studied very much about their density as function of
temperature All the results indicate that the density was decreased linearly as temperature
increases and any specific density value in the molten state can be expressed by equation as
equation 4
= A-BT [4]
Where (gcm3) is the density of salt A (gcm
3) is the initial density value at 0
oC and B
(mgcm3degC) is the density change slope as function of temperature The coefficients are shown in
16
Table 25 for the nitrate group molten salts Among these systems pure sodium nitrate has the
largest value which reveals the high initial density value at low temperature [43] Conversely
lithium nitrate has the lowest value while it presents the smallest decrease trend as temperature
increases [44] The densities and A B values of multi-component nitrate salts were included in
the range of those two salts discussed above
Table 25 Density coefficients A and B of nitrate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiNO3 1922 0556
NaNO3 2334 0767
KNO3 2127 0760
NaNO3-KNO3 2134 0773
KNO3-CaNO3-LiNO3 2172 0735
LiNO3-KNO3-NaNO3 2083 0715
Several experiments were also conducted to measure the density as function of temperature
for the individual and multi-component carbonate salt systems The density of the carbonate salt
also follow the same trend as that of nitrate salt and the temperature dependence of density
followed the linear equation as discussed above It is observed that all the carbonate salts have
higher initial density coefficient A than the nitrate salt The largest value is reached to 2511 and
even the lowest value in this group is greater than the maximum A of nitrate group [45-49]
What‟s more the regression slope coefficient B of carbonate salt is lower compared to that of the
nitrate salt group Accordingly the salts in this group present larger density in the molten state
and the density coefficient A and B are given in Table 26
17
Table 26 Density coefficients A and B of carbonate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
Li2CO3 2303 0532
Na2CO3 2350 0448
Na2CO3-K2CO3 2473 0483
Li2CO3-K2CO3 2511 0599
Li2CO3-Na2CO3 2456 0519
Li2CO3-Na2CO3-K2CO3 2364 0544
Density of metal fluoride and chloride molten salt were also examined and present similar
regression trend as temperature increases The linear temperature dependence is also expressed
by the same equation On the basis of previous literature data the pure chloride salt shows lower
density than the fluoride salt with the same cation in the molten state [49] What‟s more the
sodium halide salt has the largest density value while the lithium halide salt has the lowest value
which is very similar to the nitrate group salt The density determination coefficient A and B are
given in Table27
Table 27 Density coefficients A and B of chloridefluoride salts
Compound A(gcm3) Btimes103(gcm
3degC)
LiCl 1766 0432
NaCl 1991 0543
KCl 1976 0583
LiF 2226 0490
NaF 2581 0636
KF 2469 0651
LiF-NaF 2520 0818
LiCl-NaF-KCl 2436 0742
LiF-NaF-MgF 2240 0701
18
The density measurement of hydroxide was not conducted as much as those three anion
groups discussed above Only few data of density is available for the alkali hydroxide salt when
added into other salt systems and temperature dependence also follows the linear regression
trend [32 41] The density determination coefficient A and B are given in Table 28
Table 28 Density coefficients A and B of molten salt mixture with hydroxide salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiCl-LiOH 16 0443
LiF-LiOH 165 0471
23 Heat capacity
In the heating process the temperature of solar energy storage molten salt is increase by
absorbing energy from the solar radiation Conversely the same amount of heat is released and
applied to heating system in the process of cooling Heat capacity is the amount of heat required
to increase the temperature of certain material by 1 oC and can be viewed as the directly relevant
parameter to the energy storage ability To some extent the large heat capacity assures the
efficiency of the application of solar energy storage materials
The heat capacity of alkalialkaline nitrate salt was investigated for both individual and
multi-component system in the previous literature To simplify the comparison only the heat
capacity value at 500oC is shown in all the following tables In the liquid state the heat capacity
increases with temperature following linear equation and the increasing slope is as small as 10-5
to 10-4
[50 51] Among those alkali nitrate salt systems lithium nitrate has the largest heat
19
capacity at 500oC while potassium nitrate presents the lowest value at that temperature In table
29 the heat capacity results at the selected temperature in literature are given
Table 29 Heat capacity of alkali nitrate salt at 500oC
Compound Heat capacity(JgK)
LiNO3 2175
NaNO3 1686
KNO3 1400
NaNO3-KNO3 1533
LiNO3-KNO3 1642
LiNO3-KNO3-NaNO3 1681
For the carbonate salt systems in the molten state the heat capacity is almost constant and
almost independent with temperature [32 33] Same as the nitrate group salts the heat capacity
for pure carbonate salt decreases as the atomic number of the alkali element increases which
means the value for lithium carbonate is the largest and that of potassium carbonate is the
smallest Generally the heat capacity value for carbonate in molten state is larger than that in
solid state However the sodium-potassium carbonate binary system is an exception for which
the heat capacity in solid state is larger than liquid state In table 210 the heat capacity results of
carbonate salts at the selected temperature in literature are given
Table 210 Heat capacity of alkali carbonate salt at 500oC
Compound Heat Capacity(JgK)
Li2CO3 250
Na2CO3 178
K2CO3 151
Na2CO3-K2CO3 157
20
Li2CO3-K2CO3 160
Li2CO3-Na2CO3 209
Li2CO3-K2CO3-Na2CO3 163
The heat capacity of fluoridechloride salt was measured in several literature and found
that for the pure salt the lithium halide has the biggest heat capacity data in the molten state
while the potassium halides shows the lowest heat capacity value Similar to the carbonate group
the heat capacity value of fluoridechloride salt varies little with temperature in the liquid state
[32 33] The values at 500oC for the alkalialkaline halides are shown in Table 211
Table 211 Heat capacity of fluoridechloride salt at 500oC
Compound Heat Capacity (JgK)
LiCl 148
NaCl 115
KCl 090
LiF-KF 163
NaCl-MgCl2 100
LiF-NaF-KF 155
KCl-MgCl2-CaCl2 092
The heat capacity of pure and multi-component hydroxide salt systems is limited in the
previous literature and the values in the liquid state follow linear equation which is observed for
all the molten salt discussed above [52] The values at 500oC for the alkalialkaline halides are
shown in Table 212
21
Table 212 Heat capacity of hydroxide salt at 500oC
Compound Heat Capacity(JgK)
NaOH 188
LiOH-NaOH 221
NaOH-KOH 182
In summary on the basis of comparison of various physic-chemical properties molten
nitrate slats have relatively low melting point excellent working temperature range reasonable
density and high heat capacity As the result of that molten nitrate salt is suitable to be applied as
the thermal energy storage fluid in the solar energy storage system
22
CHAPTER 3
OBJECTIVES
Based on review of previous literature data it is found that there are several disadvantages
such as the high melting point relatively low density value or poor heat capacity in liquid state
which limit the application of molten salt in certain groups in solar thermal energy storage
system Conversely alkalialkaline nitrate salt is considered as the suitable choice and proposed
as the thermal energy storage liquid for high temperature
Currently the used thermal energy storage liquid is NaNO3 (60mol)-KNO3 (40mol)
binary system (solar salt) which has the melting point at 221oC [30] Although the melting point
for this salt mixture is not the lowest it is still emphasized because of its low investment cost
However there are some drawbacks for this binary nitrate mixture The main disadvantage is
the high melting point In evenings or in winter the molten salt can easily freeze and block the
pipeline As a result of that some auxiliary cost should be added to overcome this problem and
the total investment will be increased
Development and synthesis of newer molten salt mixtures with freezing point lower than
those currently used for thermal energy storage applications is necessary for higher efficiency of
utilization of solar energy and getting rid of any unnecessary cost The approach to develop
lower freezing point molten salt mixtures is by the prediction of new eutectic mixtures and also
23
by the development of new nitrate compounds Besides these two most well known systems
several other mixtures were also studied Preliminary evaluation of several new molten salt flux
systems based on requirements for thermal energy storage systems mainly including freezing
point density heat capacity viscosity and thermal energy storage density The promising
candidate low melting point molten salt system should satisfy the requirements that eutectic
melting temperatures are lower than 220oC and the thermal energy storage densities are higher
than binary solar salt It is known that the melting point can be lowered by the addition of one or
more ABNO3 nitrate compounds where A and B are cations Consequently several multi-
component systems which have more constituent salts than solar salt were came up with and
studied with little fundamental data on the physic-chemical properties at the required operating
conditions available at present
In this thesis the new systems with simulated eutectic compositions were tested for their
experimental melting points heat capacities using the Differential Scanning Calorimetry (DSC)
technique which is considered to be the accurate instrument for thermodynamic data analysis
[53-59] Some significant thermodynamic properties such as heat capacity enthalpy and entropy
and Gibbs energy were calculated in the thesis to evaluate the energy change of the system in the
phase change process and the potential of being applied in the parabolic trough solar power plant
The energy density was obtained by using the experimental measured density and heat capacity
of the mixtures in molten state Finally 9 down-selected systems were present and discussed
24
CHAPTER 4
THERMODYNAMIC MODELING OF SALT SYSTEMS
41 Thermodynamic modeling
To lower the melting point of solar energy storage system multi-component system is
applicable Thermodynamic model was introduced to predict the eutectic temperature of salt
systems based on the Gibbs energies of fusion of individual salt and that of mixing of constituent
binary systems At the eutectic temperature the Gibbs energies in the liquid state and solid state
of salt are equal In thermodynamics Gibbs energy of fusion can be expressed by the equation
given as follows
G = H-TS [5]
Where H is the change of enthalpy of fusion and S is the change of entropy of fusion Equally
the entropy change of fusion can be expressed by differentiating G and the equation is given
[6]
It is known that the change in entropy can be expressed in terms of change in heat capacity in the
melting process as
[7]
25
If the change of heat capacity is assume to be independent of temperature the integral of
from Tm to T can be shown as
[8]
where Sm is the entropy of fusion at the melting point which is equal to Accordingly
Eq8 can be rewritten as
[9]
Substituting Eq 9 in Eq 6 and integrating the equation from Tm to T we get
[10]
Eq 10 illustrates that by using the change of heat capacity melting point and enthalpy of fusion
the Gibbs energy change at any temperature can be obtained
The standard Gibbs energy of fusion of a salt bdquo1‟ can be expressed in terms of the activity
of the salt as
[11]
where is the molar excess Gibbs energy and X1 is the molefraction of the salt bdquo1‟ Gibbs
energy of fusion at any give temperature T is expressed by Eq 7 in terms of its molefraction and
partial molar excess Gibbs energy
26
Take LiNO3-NaNO3-KNO3 as an example in which the integral molar excess Gibbs energy is
composed of the summation of the Gibbs energies of three constituent binary system and one
ternary The expression of the integral excess Gibbs energy is given by Eq12
[12]
Gibbs energies of the three constituent binary systems LiNO3-NaNO3 LiNO3-KNO3 and
NaNO3-KNO3 of the LiNO3-NaNO3-KNO3 ternary system are taken from the literature [48 49]
The Gibbs energies of mixing or the integral excess Gibbs energies of the three constituent
binary systems of the LiNO3-NaNO3-KNO3 ternary system are given below
LiNO3-NaNO3 Binary System
Jmol [13]
LiNO3-KNO3 Binary System
Jmol [14]
NaNO3-KNO3 Binary System
Jmol [15]
When assume the intergral excess Gibbs energy of to be zero the excess Gibbs energy in
the ternary system can be expressed by the summation of three constituent binary systems
[16]
27
Generally the partial molar excess Gibbs energies are reduced from the integral molar
excess Gibbs energy and can be expressed by the generalized equation for certain ldquomrdquo
component salt as
[17]
In the ternary system the i value equals to 12 and 3 and the partial molar excess Gibbs energy
of mixing for each component can be expressed as follows
[18]
[19]
[20]
Based on Eq 7 and the partial molar excess Gibbs energy of individual component the
Gibbs energy in the fusion can be expressed as Eq21- 23
[21]
[22]
[23]
42 Calculations
The fusion of the ternary salt system is defined by solutions of Eq 21-Eq 23 Newton-
Raphson method can be used to solve these three non-linear equations by linearizing the non-
linear equations using the Taylor series and truncating the series to first order derivatives
28
Consider the three non-linear functions F G and H in three variables x y and z The three
equations that are solved for the three variables are written as
F(x y z) = 0
G(x y z) = 0
H(x y z) = 0 [24]
The partial derivatives of the function F with respect to x y and z are given as
[25]
Similarly the partials derivatives can be expressed for the other two functions G and H
Newton-Raphson iterative method of solving the three equations in three variables
essentially deals with the solution of the incremental vector in the matrix equation given below
[26]
For the initial values of x y and z (say xi yi and zi) the right hand side vector contains the
values of the functions at the initial values (xi yi and zi) The 3times3 matrix on the left hand side
contains the partial derivatives of the functions with respect to the three variables at the initial
values Solutions of the matrix equation (Eq 26) result in the increments of the variables x y
and z The variables for the next iteration will then be xi + x yi + y and zi + z The
process of solving the matrix equation (Eq 26) is continued until the increments in the variables
x y and z is less than a very small quantity The iteration process is then said to be
29
converged and the values of the variables at convergence of the solution are the roots of the
system of the three fusion equations
The composition of LiNO3 NaNO3 and KNO3 and the eutectic temperature is solved by
using the Newton-Raphson iterative method Different from the data in previous literature the
eutectic temperature for the ternary is 116oC Besides the composition for each component is
also different from those published in literatures The new molten ternary system is composed of
2592 wt LiNO3 2001 wt NaNO3 and 5407 wt KNO3 The similar method is also applied
to other multi-component systems to determine the composition and eutectic temperature The
predicted melting points for new solar energy storage system are given Table41
Table 41 Calculated composition and melting point of multi-component molten salts systems
System Composition (wt) Calc Tmp
LiNO3 NaNO3 KNO3 NaNO2 KNO2 Mg(NO3)2 MgKN (degC)
Salt 1 259 20 541 - - - - 116
Salt 2 - 161 547 292 - - - 1238
Salt 3 175 142 505 178 - - - 986
Salt 4 115 104 274 - - - 507 986
Salt 5 172 139 476 172 41 - - 957
Salt 6 9 423 336 - 151 - - 1000
Salt 7 193 - 546 237 24 - - 1081
Salt 8 193 - 559 239 - 09 - 1008
Salt 9 154 172 324 - - 83 267 1036
30
CHAPTER 5
EXPERIMENTAL PROCEDURE
51 Melting point determination of molten salt mixtures
511 Materials
Ternary quaternary and quinary nirate and nitrite mixtures were tested in the thesis Most
components in the mixtures don‟t require any pre-preparation and can be used as received The
only exception is new developed MgKN which was composed of 6667 mol KNO3 and 3333
mol Mg(NO3)2 This unique compound is synthesized from magnesium nitrate hexahydrate
(98 Alfa Aesar) and potassium nitrate (ACS 990 min Alfa Aesar) and added into the
mixture as one single component As received magnesium nitrate hexahydrate is dehydrated
before synthesizing MgKN compound Weighted amount of magnesium nitrate taken in a
stainless steel crucible and placed on a hot plate in an argon atmosphere Temperature of the salt
is measured with a thermocouple immersed in the salt The temperature was held at 52315 K for
2 hours The salt solidifies to a white mass The temperature of the salt is then raised to 57315 K
slowly to remove any traces of moisture and to ensure complete dehydration The complete
removal of water is ascertained by weight loss
512 Apparatus and Procedure
31
Differential scanning calorimetry (DSC) analysis was performed using Perkin Elmer
Diamond DSC instrument and the setup is shown in fig 51 Heat flow and temperature can be
recorded in the instrument with an accuracy of 00001 mW and 001 K respectively The
measurements were made under purified nitrogen atmosphere with a flow rate of 20ccmin and at
a heating rate of 5 Kmin
Fig 51 Photography of set-up for DSC equipment
After dehydration if necessary each component was weighed to an accuracy of 01mg with
the electrical balance and mixed thoroughly in a stainless steel crucible Later the mixture is
heated up to certain temperature at which the entire salt melts At this temperature the salt
mixture was held for about 30 minutes The salt mixture is allowed to air cool to ambient
temperature This procedure is repeated 3 to 4 times to get the well-mixed compound Standard
aluminum pan with lid used for DSC measurements are weighed before the experiment Small
amount of the synthesized compound is placed carefully in the aluminum pan and closed with
the lid The lid is crimped by a sample press and the pan is weighed The weight of the sample is
32
determined by removing the weight of the pan and lid For the determination of melting point
and heat capacity (20-25) mg of the sample was used
Perkin-Elmer Diamond Differential Scanning Calorimeter (DSC) is used to measure the
melting point and heat capacity of compound The crimped ample pan was immediately put
inside the sample chamber of DSC after preparation and held at 52315 K for 10 hours to remove
the trace amount of moisture possibly caught in the process of loading sample and also to ensure
a homogeneous mixture In the experimental procedure a temperature range from 29815 K to
52315 K was set with a heating rate of 5 K min
1 followed by a cooling cycle at the same rate
This cycle is repeated for at least 6 times to ensure good mixture of the sample and
reproducibility of the results
52 Heat Capacity determination of molten salt mixtures
To start Cp measurement the same procedure as that of melting point determination is
followed with an addition of bdquoiso-scan-iso‟ steps to the program after 5-cycle temperature scan
Starting from 29815 K the temperature was held for 5 minutes before and after each scan step
Small temperature scan range is chosen to avoid thermal resistance between device and testing
sample except when the temperature is approaching the melting temperature The upper limit for
the Cp measurement was set to 62315 K in our experiments Since the change in the molar heat
capacity of the salt in the liquid state is very small the Cp data in the liquid state can be easily fit
to an equation and extrapolated to higher temperatures To get the value of molar heat capacity
of the sample heat flow curve for the baseline of the empty sample pan also needs to be obtained
immediately following the identical ldquoiso-scan-isordquo steps which were used for the actual sample
33
run The difference of heat flow between the actual crimpled sample and the empty sample pan is
the absolute heat absorbed by the test sample
53 Density determination of molten salt mixtures
Density measurement was carried out with standard densitometer which has fixed volume
Initial weight of the densitometer is measured and noted Salt composition of which the density
is measured is placed in a beaker on a hot place The densitometer is also placed on the same hot
plate The temperature is set to a fixed value above the melting point of the salt and is measured
by a thermocouple After the salt is melted and when the temperature shows stable reading the
molten salt is poured in to the densitometer up to the set mark on the sensitometer bottle The
weight of the densitometer with the molten salt is measured The weight difference between this
weight and the weight of empty densitometer gives the weight of the molten salt at the fixed set
temperature By knowing the fixed volume in the densitometer the density of the salt at that
temperature can be calculated This procedure is repeated at least three times to accurately
determine the density of the salt
34
CHAPTER 6
RESULT AND DISCUSSION
61 Melting point determination
611 DSC equipment calibration
Before the actual melting point measurement pure indium zinc metal and several
individual salts were used to calibrate the DSC equipment For metals only one sharp peak was
observed for each and the heat flow curve for indium metal is shown in fig 61 However larger
and boarder peaks are found for salts just like the condition illustrated in fig 62 for pure
potassium nitrate Based on the results shown in Table 61 the experimental data for melting
points and enthalpies of fusion have excellent agreement with the literature values [60-63] The
variation of point is within 07 and the variation of change of enthalpy is less than 3
Figure 61 Melting point calibration with indium sample
35
Figure 62 Melting point calibration with KNO3 sample
Table 61 Calibration data of melting points with different samples
Sample
Lit
Tmp
Expt
Tmp
Lit
Ttrans
Expt
Ttrans
Lit
ΔHfusion
Expt
ΔHfusion
Lit
ΔHtrans
Expt
ΔHtrans
degC degC degC degC Jg Jg Jg Jg
Indium 1566 1563 - - 286 278 - -
Zinc 4195 4188 - - 1086 1068 - -
LiNO3 2567 2550 - - 3617 3633 - -
NaNO3 3100 3081 2770 2753 1777 1756 147 152
KNO3 3370 3372 1330 1332 993 1005 538 529
612 Results
Differential scanning calorimetry (DSC) was used to determine the melting point and any
solid state phase transitions of the salt mixture A low scanning rate was chosen to record the
heat flow curve as function of temperature in order to improve the sensitivity of detection [64] It
helps to pick up any small endothermic peaks and also avoids the thermal resistance between the
36
internal furnace and sample Nine systems were chosen to test and the eutectic composition is
already listed in Table 41
All the selected systems are composed of alkaline nitrate and nitrite and most of them have
three basic components which are lithium sodium potassium nitrate or nitrite All the quaternary
and quinary systems were developed on the basis of the LiNO3-NaNO3-KNO3 baseline ternary
Figure 63-611 shows the DSC plot of all the salt systems DSC plots for each system were
collected for at least five runs (each run with fresh salt preparation) to ensure the reproducibility
All the onset temperatures peak temperatures predicted temperatures enthalpy of fusion for
melting peaks and the solid phase transformation temperatures are given in Table62
Figure 63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt
37
Figure 64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt
Figure 65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt
38
Figure 66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt
Figure 67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt
39
Figure 68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
Figure 69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
40
Figure 610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt
Figure 611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN salt
Table 62 illustrates that the predicted melting point is close to the experimental
determined value and most deviation is within 10 except for system 9 The great agreement
41
between experimental and calculated data verifies the accuracy and feasibility of the
thermodynamic modeling
Table 62 DSC results of melting point transition point and predicted melting point
System Tmp Ttrans ΔHfusion
Calculated degC Onset degC Peak degC Peak degC Jg
Salt 1 1160 994 1191 1043 600
Salt 2 1238 1150 1240 NA 97
Salt 3 986 940 999 NA 244
Salt 4 986 940 1010 NA 60
Salt 5 957 910 950 NA 62
Salt 6 1000 930 960 NA 86
Salt 7 1081 992 1003 793 60
Salt 8 1008 1010 1019 853 59
Salt 9 1036 834 892 NA 93
613 Discussion
It is observed that the first curve is different from last ones shown in the DSC plots and
this phenomenon is common for all the melting point measurement with DSC technique This
happened because in the first cycle the moisture caught by salt mixture especially the lithium
nitrate was removed in the process of heating Moreover the partially solidified sample in the
sample loading process can be re-homogenized in the first heating cycle [65-67] In figure 63
69 and 610 more than one endothermic peak was found The first smaller endothermic peak
refers to solid state phase transition of the salt mixture The second larger endothermic peak
refers to the melting of the salt Normally the onset temperature of transition is taken as the
experimental transition point for any metallic sample However in case of molten salts mixtures
since the thermal conductivity is low [68-74] the complete transition is ensured only at the peak
42
transition temperature The thermal gradient which exists due to the low thermal conductivity of
the salt results in internal heat flow which enhances the mixing in the salt Thus the transition
temperature is defined as the peak temperature of phase transition For salt No1 the small
endothermic peak happened before and was connected to the main peak which occurred at
39027K The first endothermic peaks for salt No 7 and 8 occurred at almost the same
temperature because of the similar composition for these two compounds Since the small
amount of magnesium nitrate and potassium nitrite contained in these two compounds the small
endothermic peak can hardly be related to these two components Obviously the rest three major
components must have something to do with the first peaks happened before the melting peaks
for both cases Each component among the major three ones were tested to find out any possible
solid phase transition peaks of them and the results shown in Table 63 which reveals that
lithium nitrate doesnt have any phase transition peak in solid state while potassium nitrate and
sodium nitrite both own the solid phase transformation peaks before their melting peaks
Table 63 Fusion and solid phase transition temperature for individual salts
System Tmp degC Ttrans degC ΔHfusion Jg ΔHtrans Jg
LiNO3 2550 - 3633 -
KNO3 3372 1332 1005 529
NaNO2 4311 4170 1119 880
The further investigation was carried out by running the KNO3-NaNO2 (550 wt and 238 wt )
binary compound with the very similar weight percentage as that in salt No 7 (546 wt and
237 wt) and salt No 8 (559wt and 239wt) By converting the weight percentage of the
studied binary system into 100 scale the weight fraction for sodium nitrate and potassium
nitrate can be rewritten as 698wt and 302wt The DSC plot for this binary system was
43
shown in fig 612 Although the solid transition and melting temperature were brought down by
adding lithium nitrate the shape of the plots in fig 69 and 610 are identical to that shown in fig
612 The enthalpy of solid state transformation of the binary salt was also converted to that in
both quaternary systems by using the weight fraction occupied by the binary system and the
comparable change of converted enthalpy between the binary system and two quaternary systems
indicates the relevance of the solid transition peaks in salt 7 and 8 to the combined effect of
potassium nitrate and sodium nitrite
Figure 612 DSC plot of 698wt KNO3- 302wt NaNO2 binary system
The similar analysis was applied to No1 salt to find out the reason for the presence of a
small peak adherent to the main melting peak before the melting point Sodium nitrate and
potassium nitrate binary system was synthesized based on the weight fraction of these two
constituent salts in No 1 salt DSC plot for the sodium nitrate-potassium nitrate binary system in
Fig 613 with the converted composition which is essentially same as that in the No1 ternary
system shows smooth heat flow curve before the melting peak which means the solid transition
peak in ternary is not simply relative to the binary system Assumption was made that the solid
44
phase transformation peak in the ternary salt is resulted from a multiple effect ie the
combination of one of the eutectic binary system involved in the ternary salt mixture and the
other binary system which is composed of the rest components The statement is verified that the
small peak in salt 1 is mainly caused by the solid phase transformation peak in lithium nitrate-
potassium nitrate eutectic binary system given the similar shape of the DSC plots in Fig 614
Since in salt No1 there is excess amount of sodium nitrate to form the lithium nitrate-sodium
nitrate binary system the rest sodium nitrate can interact with potassium nitrate and form new
sodium-potassium nitrate system which is shown in fig615 Besides a solid phase
transformation peak is observed in fig615 which has a very small area and won‟t change the
shape of phase transformation peak in fig614 when these two binary systems are combined and
form salt 1 The enthalpies of solid state transformation in two binary salts were also converted
to that in salt 1 by using the weight fractions occupied by both binary systems The difference
of the change of converted enthalpies between the lithium-potassium nitrate eutectic binary and
ternary system is filled by the binary mixture which is composed of the rest components sodium
nitrate-potassium nitrate The comparable converted values of enthalpy change between salt 1
and its two constituent binary systems further verify the assumption that the solid phase
transformation happened in salt 1 is mainly due to the combined effect of LiNO3-KNO3 eutectic
binary system and NaNO3-KNO3 binary system
45
Figure613 DSC plot of 270wt NaNO3-730wt KNO3 binary system
Figure614 DSC plot of 458wtLiNO3-542wtKNO3 binary system
46
Figure615 DSC plot of 460wt NaNO3-540wt KNO3 binary system
Unlike those discussed mixtures above salt No2 Salt No4 Salt No5 and Salt No6 have
only one relatively board melting peak and the heat flow curve before and after are very stable
Similarly there is no solid transformation peaks observed in salt No3 salt No7 and salt No8
However the heat flow after the melting peak in these cases are not stable and the main
endothermic peak is followed by a small hump which is considered to be the recrystallization
process once the compound entered into the liquid state When the process is finished the heat
flow curve returns to steady state
Heating rate is a significant parameter when collect the heat flow curves by using DSC
technique Fig 616(a) and Fig 616(b) illustrate the difference of melting point for salt No6 due
to the change of heating rate If the heating rate is 20oCmin the peak temperature and onset
temperature for the melting peak is 9669oC and 9221
oC respectively Once the heating rate is
decreased to 5oCmin these two temperatures will also be lowered to 9614
oC and 9190
oC The
difference is resulted from the diverse amount of thermal resistance between the testing sample
and the furnace inside the DSC instrument [75] Under higher heating rate the decisive thermal
47
resistance is raised due to the low thermal conductivity medium between the furnace and the
actual sample The insensitivity of gas heat conduction medium in DSC results each unit of
temperature increase on one side cannot have an immediate response on the other side of the gas
Consequently the sample holder which is connected the furnace has a higher temperature than
that inside the sample In this condition the value of temperature profile collected as the sample
holder temperature is larger than the actual temperature The deviation will be much smaller
when the heating rate is reduced In the case the thermal resistance will be decreased because of
the lower temperature gradient of the gas medium in the heating process As a result of that the
collected temperature from the sensor attached to the sample holder will be very close to the
actual temperature inside the testing sample
Figure 616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 20oCmin
heating rate
48
Figure 616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 5oCmin
heating rate
Besides the difference of temperature while using higher and lower heat rate the solution
of DSC will also be affected by different heating rate Fig 617(a) shows the DSC plot for salt
No 7 using the heating rate as 5oCmin and the DSC plot in Fig 617(b) is collected under the
heating rate as 20oCmin It can be observed that in the lower heating rate two small separated
peaks can be viewed as two parts of the solid phase transformation process while in Fig 617(b)
two small peaks before the melting peak merge and present as a board hump The qualification
of resolution can be executed by the term named resolution factor RMKE which is calculated as
the ratio of the peak heat flow value of the separated peaks to that of the concave point between
two peaks The equation for determining RMIKE is given in Eq 27 [76 77]
RMIKE =hpeakhmin [27]
49
Figure 617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 5oCmin
heating rate
Figure 617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 20oCmin
heating rate
In the case of lower heating rate the RMKE is determined to be 15 and the value for higher
heating rate is not available because the concave point of heat flow doesn‟t exist from
Fig617(b) Since the higher RMKE value indicates better resolution it can be stated that the
50
lower heating rate also results in greater sensitivity of the equipment to pick up any small
endothermic peaks
Besides the down-selected 9 compounds some more salt mixtures were also tested Most
of them were not selected to the final candidate for the thermal energy storage application
because of their higher melting point Table 64 gives some of the trial systems measured with
DSC technique It is illustrated that the melting points of mixtures with lower or even no content
of lithium nitrate turn out to be higher than those with sufficient amount of lithium nitrate For
most of the mixtures with melting point lower than 120oC the amount of lithium nitrate should
be larger than 81wt Also all of the systems in table 64 with lithium nitrate less than 15wt
have melting point higher than 140oC Based on the observation above it is concluded that the
lithium nitrate can be used as an additive to bring the melting point down for thermal energy
storage systems
51
Table 64 Melting points of candidate systems as function of temperatures
System Composition (wt)
Onset
Temp
Peak
Temp
(oC) (
oC)
LiNO3 ndash NaNO3 ndash KNO2 107 459 434 890 910
LiNO3 - KNO3 - NaNO2 196 564 241
1024 1046
LiNO3 - NaNO3 - KNO3 - KNO2 90 423 337 151
930 960
LiNO3 - NaNO3 - NaNO2 - KNO2 81 454 65 401
900 910
LiNO3 - KNO3 - NaNO2 - KNO2 193 546 237 24
992 1003
LiNO3 - KNO3 - NaNO2 ndash Mg(NO3)2 193 559 238 09
1010 1020
LiNO3 - NaNO3 - KNO3 - Mg(NO3)2
- MgK 154 172 324 83 267 834 892
LiNO3 - NaNO3 - KNO2 ndash Ca(NO3)2 14 390 333 263
1250 1470
NaNO3 - KNO3 - NaNO2 - KNO2 425 163 71 341
1407 1447
NaNO3 - KNO3 - KNO2 ndash Mg(NO3)2 432 146 380 42
1386 1421
NaNO3 - NaNO2 - KNO2 - Ca(NO3)2 451 92 410 48
1150 1390
LiNO3 - NaNO3 - NaNO2 - KNO2 -
Ca(NO3)2 15 393 37 323 232 1380 1480
LiNO3 - NaNO3 - KNO2 - Ca(NO3)2 -
Mg(NO3)2 14 379 313 275 20 1339 1534
62 Heat capacity determination
621 Heat capacity calibration
DSC was also calibrated for the heat capacity measurement Lithium nitrate sodium
nitrate and potassium nitrate were examined for the heat capacities from room temperature to
upper limit temperature for the instrument In liquid state the heat capacity values for each salt
can be fit to straight line with trace amount of increasing trend Since the temperature range from
the onset temperature of liquid state to the upper limit of DSC is relatively small the heat
capacity values for pure individual salts can be viewed as constants The comparison between the
theoretical and experimental heat capacity data is given in Table 65 Except lithium nitrate the
52
experimental heat capacities data for the rest two systems are almost same as the literature Even
for lithium nitrate which demonstrates the biggest difference from the literature data the 28
vibration is still within a reasonable range
Table 65 Calibration data of heat capacities with different samples
Sample Lit Cp Expt Cp
JgK JgK
LiNO3 218 212
NaNO3 169 167
KNO3 140 139
622 Results
The materials used in the heat capacity measurements are the same as those in the melting
point experiments Molar heat capacities of the all compound were measured by the DSC
equipment from room temperature to 62315 K The heat flow is recorded as a function of
temperature in ldquoiso-scan-isordquo steps at intervals of 20 K The bdquoiso stage‟ refers to isothermal
holding at a particular temperature bdquoscan stage‟ refers to the heat flow recording at a heating rate
of 5 K min1
up to a an increment of 25 K followed by another isothermal holding stage This is
a standard procedure followed in the measurement of heat capacity of materials using the DSC
equipment [63 64] This procedure of heat capacity measurement has two advantages (i) any
heat fluctuations during the recording are avoided by the isothermal steps and (ii) any phase
transition can be highlighted by the choice of temperature range The absolute heat flow to the
sample is determined by subtracting the heat flow collected by running a baseline curve with an
empty pan Because the heat capacity measurement in the heating process corresponds to
53
collecting the value of required heat flow at each temperature all the heat capacity plots have the
same shape with that of heat flow in the melting point measurements Take the heat capacity plot
of LiNO3-NaNO3-KNO3 ternary system as an instance which is shown in fig 618 the heat
capacity curve also has two different peaks The first little peaks corresponds to one occurs at
39027K which was observed in fig 63 the second large and sharp peak happened right after the
small one is prevalent to the endothermic peak with the peak temperature as 39027 K Similarly
after the phase transformation the heat capacity in liquid state becomes very stable and increase
with temperature linearly with little slope
Fig 618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system as function of
temperature
The heat capacity change as function of temperature for salt No1 was illustrated in fig
619 Based on the trend of heat capacity in the liquid state any value for the system in the liquid
can be extrapolated The expressions for heat capacity in liquid state for the new molten salt
systems were discussed and given in the next sectionTable66 shows the specific heat capacity
54
of the all the selective compounds measured at 62315 K and extrapolated at 77315K Besides
the molar heat capacities at 77315K are given in Table 66 of all the salts
Fig 619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K
Table 66 Heat capacity of selected new TES molten salt mixtures
System Expt (62315K) Extrapolated(77315K) Extrapolated(77315K)
Cp JgK Cp JgK Molar Cp JmolK
Salt 1 153 170 1521
Salt 2 143 168 1515
Salt 3 148 155 2183
Salt 4 153 166 1411
Salt 5 153 170 1440
Salt 6 151 163 1435
Salt 7 156 167 1443
Salt 8 155 168 1410
Salt 9 161 170 1937
55
623 Thermodynamic properties
The standard thermodynamic properties such as entropy enthalpy and Gibbs energy for
salt mixtures are determined from the experimental data of melting point and heat capacity in the
temperature range of the present study and expression for determining these properties are given
in equation 28-30 In thermodynamics all these three properties are related to heat capacity and
its variances with temperature In the studied temperature range (29815K-62315K) they can be
described as expression includes heat capacity
[28]
[29]
[30]
Where Tt is the solid transformation temperature Tmp is the melting point ΔHt is enthalpy of
solid phase transformation and ΔHfusion is enthalpy of fusion The standard thermodynamic
properties entropy enthalpy and Gibbs energies as function of temperature for each compound
are expressed in the following section
6231 LiNO3-NaNO3-KNO3 (Salt 1)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3
compound (i) solid state 1 (32315-38415) K (ii) liquid state (40315-62315) K Accordingly
56
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62311 Heat capacity of solid state 1 (29815-38415) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the solid state 1 in the
temperature range of 29815 to 38415 K is fit to a second order polynomial equation Eqn (31)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[31]
( ) K
R2 = 0982
62312 Heat capacity of liquid state (40315-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a linear equation Eqn (32) gives the linear
equation along with the least square fit parameter (R2) in the temperature range for the liquid
state of the compound
JKmol [32]
57
R2 = 0947
Heat capacity data of the LiNO3-NaNO3-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62313 Thermodynamic properties of solid state 1(29815-38415) K
JKmol [33]
Jmol [34]
[35]
Jmol
62314 Thermodynamic properties of liquid state 2(40315-62315) K
[36]
58
JKmol
Jmol [37]
[38]
Jmol
Among the equations above equation (33)-(35) refer to the thermodynamic properties for
solid state equations (36)-(38) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature ranges for solid and liquid state are
given in Table A1 and A2 in appendix A respectively with the corresponding heat capacity as
function of temperature
6232 NaNO3-NaNO2-KNO3 (Salt 2)
The heat capacity data can be divided into two sections for NaNO3-NaNO2-KNO3
compound (i) solid state 1 (32315-39215) K (ii) liquid state (41315-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62321 Heat capacity of solid state 1 (29815-39215) K
59
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the solid state in the
temperature range of 29815 to 39215 K is fit to a second order polynomial equation Eqn (39)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[39]
( ) K
R2 = 0978
62322 Heat capacity of liquid state (40315-62315) K
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a second order polynomial equation Eqn (40)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[40]
R2 = 0941
60
Heat capacity data of the NaNO3-NaNO2-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62323 Thermodynamic properties of solid state 1(29815-39215) K
JKmol [41]
Jmol [42]
[43]
Jmol
62324 Thermodynamic properties of liquid state 2(40315-62315) K
JKmol [44]
61
Jmol [45]
[46]
Jmol
Among the equations above equation (41)-(43) refer to the thermodynamic properties for
solid state equations (44)-(46) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table B1 and B2 in appendix B respectively with the corresponding heat capacity as
function of temperature
6233 LiNO3-NaNO3 -KNO3-MgK (Salt 3)
The heat capacity data can be divided into two sections for LiNO3-NaNO3 -KNO3-MgK
compound (i) solid state 1 (29815-36415) K (ii) liquid state (42115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62331 Heat capacity of solid state 1 (29815-36415) K
62
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the solid state in the
temperature range of 29815 to 36415 K is fit to a second order polynomial equation Eqn (47)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[47]
( ) K
R2 = 0995
62332 Heat capacity of liquid state (42115-62315) K
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the liquid state in the
temperature range of 42115 to 62315 K is fit to a second order polynomial equation Eqn (48)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[48]
R2 = 0963
63
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
62333 Thermodynamic properties of solid state 1(29815-36415) K
JKmol [49]
Jmol [50]
[51]
Jmol
62334 Thermodynamic properties of liquid state 2(42115-62315) K
64
JKmol [52]
Jmol [53]
[54] [29]
Jmol
Among the equations above equation (49)-(51) refer to the thermodynamic properties for
solid state equations (52)-(54) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table C1and C2 in appendix C respectively with the corresponding heat capacity as
function of temperature
6234 LiNO3-NaNO3-KNO3-NaNO2 (Salt 4)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-NaNO2
compound (i) solid state 1 (29815-36315) K (ii) liquid state (38115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62341 Heat capacity of solid state 1 (29815-36315) K
65
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the solid state in the
temperature range of 29815 to 36315 K is fit to a second order polynomial equation Eqn (55)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[55]
( ) K
R2 = 0995
62342 Heat capacity of liquid state (38115-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the liquid state in the
temperature range of 38115 to 62315 K is fit to a second order polynomial equation Eqn (56)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[56]
R2 = 0972
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
66
62343 Thermodynamic properties of solid state 1(29815-36315) K
JKmol [57]
Jmol [58]
[59]
Jmol
62344 Thermodynamic properties of liquid state 2(38115-62315) K
JKmol [60]
Jmol [61]
67
[37]
Jmol [62]
Among the equations above equation (57)-(59) refer to the thermodynamic properties for
solid state equations (60)-(62) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table D1 and D2 in appendix D respectively with the corresponding heat capacity as
function of temperature
6235 LiNO3-NaNO3-NaNO2-KNO3-KNO2 (Salt 5)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-NaNO2-KNO3-
KNO2 compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62351 Heat capacity of solid state 1 (29815-35915) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
in the temperature range of 29815 to 35915 K is fit to a second order polynomial equation Eqn
(63) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
68
[63]
( ) K
R2 = 0996
62352 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the liquid
state in the temperature range of 37515 to 62315 K is fit to a second order polynomial equation
Eqn (64) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[64]
R2 = 0969
Heat capacity data of the LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62353 Thermodynamic properties of Solid state 1(29815-35915) K
JKmol [65]
69
Jmol [66]
[67]
Jmol
62354 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [68]
Jmol [69]
[45]
Jmol [70]
70
Among the equations above equation (65)-(67) refer to the thermodynamic properties for
solid state equations (68)-(70) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table E1 and E2 in appendix E respectively with the corresponding heat capacity as
function of temperature
6236 LiNO3-NaNO3-KNO3-KNO2 (Salt 6)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-KNO2
compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62361 Heat capacity of solid state 1 (29815-36515) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the solid state in the
temperature range of 29815 to 36515 K is fit to a second order polynomial equation Eqn (71)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[71]
( ) K
R2 = 0998
71
62362 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the liquid state in the
temperature range of 37515 to 62315 K is given in Table 20 The data is fit to a second order
polynomial equation Eqn (72) gives the linear equation along with the least square fit parameter
(R2) in the temperature range for the liquid state of the compound
[72]
R2 = 0953
Heat capacity data of the LiNO3-NaNO3-KNO3-KNO2 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62363 Thermodynamic properties of solid state 1(29815-35915) K
JKmol [73]
Jmol [74]
72
[75]
Jmol
62364 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [76]
Jmol [77]
Jmol [78]
Among the equations above equation (73)-(75) refer to the thermodynamic properties for
solid state equations (76)-(78) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
73
given in Table F1 and F2 in appendix F respectively with the corresponding heat capacity as
function of temperature
6237 LiNO3-KNO3-NaNO2-KNO2 (Salt 7)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62371 Heat capacity of solid state 1 (29815-35415) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 1 in
the temperature range of 29815 to 35415 K is fit to a second order polynomial equation Eqn
(79) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[79]
(29815-35415) K
R2 = 0993
62372 Heat capacity of solid state 2 (36215-37315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 2 in
the temperature range of 36215 to 37315 K is fit to a second order polynomial equation Eqn
74
(80) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 2 of the compound
[80]
R2 = 0977
62373 Heat capacity of liquid state (37915-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the liquid state in the
temperature range of 37915 to 62315 K is fit to a linear equation Eqn (81) gives the
polynomial equation along with the least square fit parameter (R2) in the temperature range for
the liquid state of the compound
[81]
R2 = 0961
Heat capacity data of the LiNO3-KNO3-NaNO2-KNO2 compound in the two solid states
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62374 Thermodynamic properties of solid state 1(29815-35415) K
75
JKmol [82]
Jmol [83]
[84]
Jmol
62375 Thermodynamic properties of solid state 2(36215-37315) K
JKmol [85]
Jmol [86]
76
[87] [62]
Jmol
62376 Thermodynamic properties of liquid state (37915-62315) K
JKmol [88]
Jmol [89]
Jmol [90]
Among the equations above equation (82)-(84) refer to the thermodynamic properties for
solid 1 equation (85)-(87) refer to the thermodynamic properties for solid 2 equations (88)-(90)
refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy values
77
in the studied temperature range for solid 1 solid 2 and liquid state are given in Table G1-G3 in
appendix G respectively with the corresponding heat capacity as function of temperature
6238 LiNO3-KNO3-NaNO2-Mg(NO3)2 (salt 8)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62381 Heat capacity of solid state 1 (29815-33715) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid
state 1 in the temperature range of 29815 to 33715 K is fit to a second order polynomial
equation Eqn (91) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the solid state 1 of the compound
[91]
(29815-33715) K
R2 = 0994
62382 Heat capacity of solid state 2 (36115-36415) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid state 2
in the temperature range of 36115 to 36415 K is given in Table 4 The data is fit to a second
78
order polynomial equation Eqn (92) gives the polynomial equation along with the least square
fit parameter (R2) in the temperature range for the solid state 2 of the compound
[92]
R2 = 0992
62383 Heat capacity of liquid state (41115-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the liquid state in
the temperature range of 41115 to 62315 K is given in Table 5 The data is fit to a linear
equation Eqn (93) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the liquid state of the compound
[93]
R2 = 0934
Heat capacity data of the LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the two solid
states follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62384 Solid state 1(29815-35415) K
79
JKmol [94]
Jmol [95]
[96]
Jmol
62385 Solid state 2(36115-36415) K
JKmol [97]
80
Jmol [98]
[99] [74]
Jmol
62386 Liquid state (41115-62315) K
JKmol [100]
Jmol [101]
Jmol [102]
Among the equations above equation (94)-(96) refer to the thermodynamic properties for
solid 1 equation (97)-(99) refer to the thermodynamic properties for solid 2 equations (100)-
(102) refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy
81
values in the studied temperature range for solid 1 solid 2 and liquid state are given in Table H1
and H2 in appendix H respectively with the corresponding heat capacity as function of
temperature
6239 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK(Salt 9)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-
Mg(NO3)2-MgK compound (i) solid state 1 (29815-35315) K (ii) liquid state (39115-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62391 Heat capacity of solid state 1 (29815-35315) K
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state in the temperature range of 29815 to 35315 K is fit to a second order polynomial equation
Eqn (103) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[103]
( ) K
R2 = 0996
62392 Heat capacity of liquid state (39115-62315) K
82
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the liquid
state in the temperature range of 39115 to 62315 K is fit to a second order polynomial equation
Eqn (104) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[104]
R2 = 0951
Heat capacity data of the LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62393 Solid state 1(29815-35315) K
JKmol [105]
Jmol [106]
83
[107]
Jmol
62394 Liquid state 2(39115-62315) K
JKmol [108]
Jmol [109]
[110]
Jmol
Among the equations above equation (105)-(107) refer to the thermodynamic properties
for solid state equations (108)-(110) refer to thermodynamic properties of the liquid The
entropy enthalpy and Gibbs energy values in the studied temperature range for solid and liquid
state are given in Table I1 and I2 in appendix I respectively with the corresponding heat
capacity as function of temperature
84
624 Discussion of Gibbs energy change for molten salts
The Gibbs energy change data as function of temperature for 9 systems are given in fig
620 and the values at 62315K are shown in Table 67 Every system demonstrates continuous
curve throughout the whole studied temperature range Most of systems have similar Gibbs
energy change values for each temperature spot due to the comparable compositions and
properties of constituent salts However salt 3 and salt 9 Both of these salts have certain
amount of MgKN compound which presents large absolute amount of change of Gibbs energy in
the same studied temperature range [66] Since the change of Gibbs energy for multi-component
mixture is relevant to that of each constituent salt the large absolute value of ΔG of MgKN
mainly contributes to the largely negative value of salt 3 and salt 9 shown in fig 620 Besides
it is observed that most systems contain nitrite salts present lower absolute value of Gibbs energy
change For example salt 1 doesn‟t include any nitrite salt and has a relatively high absolute
value of Gibbs energy change as 1704kJmol while other systems having nitrite salts show lower
value varies from 1372kJmol to 1592kJmol
85
Fig 620 Change of Gibbs energy as function of temperature for molten salt systems
Table 67 Change of Gibbs energy values at 62315K for molten salt systems
SNo System ΔG(kJmol)
1 LiNO3-NaNO3-KNO3 1704
2 NaNO3- NaNO2- KNO3 1372
3 LiNO3- NaNO3- KNO3- MgKN 2807
4 LiNO3- NaNO3- KNO3- NaNO2 1443
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1441
6 LiNO3-NaNO3-KNO3-KNO2 1570
7 LiNO3-KNO3-NaNO2-KNO2 1592
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1583
9 LiNO3-NaNO3-KNO3-Mg(NO3)2 -MgKN 2217
86
63 Density determination
631 Density calibration
Several pure molten salts are used to calibrate the density measurement set-up before the
actual density measurement All the density values decrease as function of temperature in the
liquid state and follow the same linear equations as described in eq 4 The experimental values
at 350oC for KNO3 NaNO3 and LiNO3 are selected to compare with the literature data at the
same temperature The results are shown in Table 68 Based on the comparison of the literature
data and the experimental data the variation of density for molten nitrate salt is within in 4
Table 68 Calibration of density measurements with different pure nitrate salts
Sample Literature density Experimental density
gcm3 gcm
3
LiNO3 1727 1701
NaNO3 2066 2144
KNO3 1860 1855
632 Results and discussions
The density result of the salt as function of temperature is plotted for all the salts in Figure
621 and Figure 622 It is observed that the temperature dependence of density above the
melting point is different from that in solid state As known in solid state the density of salt has
an exponential relation with temperature while in these liquid cases the density values have
linearly dependence with temperature The stable variation as function of temperature allows the
extrapolation of density at even higher temperature The regression analysis is performed to get
the coefficient used for describing eq 4 and the results for the coefficients are shown in
87
Table69 [78-80] It is observed that the change of composition is implied on the coefficient A
which indicates the initial point at 150oC The temperature dependence coefficient B doesn‟t
change much with composition which may be mainly affected by the group of anion and cation
Table 69 Coefficient A and B for density determination of salt 1-salt 9
Salt No System A Btimes10
3
(gcm3) (gcm
3degC)
1 LiNO3-NaNO3-KNO3 2032 0493
2 NaNO3- NaNO2- KNO3 2081 0570
3 LiNO3- NaNO3- KNO3-MgKN 2055 0526
4 LiNO3- NaNO3- KNO3- NaNO2 2033 0520
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 2018 0485
6 LiNO3-NaNO3-KNO3-KNO2 2060 0554
7 LiNO3-KNO3-NaNO2-KNO2 2048 0554
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 2044 0524
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 2060 0566
Figure 621 The densities of the salt 1-salt 5 as function of temperature
88
In figure 621 all the density values are clustered around 198gcm3 at 150
oC to
186gcm3 at high temperature end and the deviation of density between all the mixtures is within
in 0047g cm3 Among all the salt mixtures the NaNO3-NaNO2-KNO3 ternary system
demonstrates the highest density value throughout the studied temperature range and LiNO3-
NaNO3-KNO3 ternary system LiNO3- NaNO3-KNO3-NaNO2 quaternary system and LiNO3-
NaNO3-KNO3-NaNO2-KNO2 quinary system show densities at the bottom side of Fig 621 For
salt 2 which doesn‟t contain any lithium nitrate the density at every selected temperature spot
is obviously higher than that of salt 1 4 and 5 which have large amount of lithium nitrate
Moreover the salt 3 which contains the relatively small amount of lithium nitrate stays in
between of salt 1 and salt 2 This comparison illustrates that the addition of lithium nitrate has
an offsetting effect on density for molten salt and it is consistent with previous literature reports
[81] The four systems presented in figure 622 also show even closer density values in the
studied temperature range Similarly salt 6 which contains the least lithium nitrate has the
largest density Salt 7 and salt 8 have almost same composition for the three dominating
components as a result of that the density curves for both mixtures are determined by the same
regression coefficient A and B Moreover the larger amount of lithium nitrate involved in these
two salt mixtures contributes to the lower density given in figure622 which further verifies the
significantly offsetting effect of lithium nitrate on density
89
Figure 622 The densities of the salt 6-salt 9 as function of temperature
The salt mixtures with maximum and minimum amount of lithium nitrate were plotted and
compared with equimolar NaNO3-KNO3 binary system and pure KNO3 salt in Fig623 [82 83]
It is observed that the NaNO3-KNO3 binary system has very similar density value to that of salt
2 because of the analogous type and composition of component in both salts The density of
pure KNO3 is slightly lower than the binary salt mixture which indicates the density of NaNO3 is
close to but higher than KNO3 in the studied temperature range Salt 1 shows the lowest density
in Fig623 due to the offsetting effect on density caused by lithium nitrate which has been
discussed above
90
Figure 623 Density of the salt 1 salt 2 as function of temperature compared to the
equimolar NaNO3-KNO3 binary system and pure KNO3
64 Thermal energy storage density of molten salts
The energy density which is considered as one of the most significant parameters of TES
application can be evaluated by calculation based on the measured density heat capacity and
working temperature range The equation of the thermal energy storage density (E) at working
temperature of 500oC is expressed in equation 111
E = Cp (500-Tm) [111]
Where Cp and are extrapolated heat capacity and density at 500oC respectively Tm is
melting point for salt mixture The extrapolation of density and heat capacity is based on the
linear temperature dependence for both parameters in molten state and the values are shown in
Table 610
91
Table 610 Extrapolated value of density and heat capacity at 500oC of salt 1-salt 9
Salt
No System
Density Heat Capacity
(gmL) (JgK)
1 LiNO3-NaNO3-KNO3 1785 170
2 NaNO3- NaNO2- KNO3 1796 168
3 LiNO3-NaNO3-KNO3-MgK 1773 155
4 LiNO3- NaNO3- KNO3- NaNO2 1792 166
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1796 170
6 LiNO3-NaNO3-KNO3-KNO2 1783 163
7 LiNO3-KNO3-NaNO2-KNO2 1771 167
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1782 168
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 1777 170
The calculated energy density for each salt is given in Table 611 compared with that of
solar salt (NaNO3-KNO3) All the new synthesized salt mixtures have significantly higher energy
density than solar salt and salt 3 shows the highest energy density among the new salts
Although salt 1 has higher heat capacity and good melting point the energy density is still the
lowest among new salt mixtures given by the effect of low density The conclusion can be drawn
from these observations that the energy density is a property affected by multiple parameters and
every part plays an important role in determining the efficiency of energy storage of salt
mixtures
92
Table 611 Energy density of salt 1-salt 9 compare to solar salt
The gravimetric storage density of new molten salts are listed in Table 612 and compared
with those different storage systems in fig 624 It is found that in the parabolic trough working
temperature range the gravimetric storage densities of new molten salts are located on the higher
side Even though some reported sensible energy storage liquids have larger gravimetric density
values than the new salts the maximum working temperatures reveal the instable working
condition at 500oC Taking conversion efficiency thermal stability and gravimetric storage
density into considerations the new molten salts are the most suitable choices of the sensible
heat storage for parabolic trough application
Salt No System Energy Density
500degC (MJm3)
0 NaNO3- KNO3 756
1 LiNO3-NaNO3-KNO3 1162
2 NaNO3- NaNO2- KNO3 1135
3 LiNO3-NaNO
3-KNO
3-MgKN 1099
4 LiNO3- NaNO
3- KNO
3- NaNO
2 1189
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1232
6 LiNO3-NaNO3-KNO3-KNO2 1174
7 LiNO3-KNO3-NaNO2-KNO2 1183
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1192
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 1242
93
Fig 624 Gravimetric storage density comparison of different energy storage systems as
function of temperature
Table 612 Gravimetric storage densities for solar salt and new molten salts
Salt
No System
Gravimetric Storage Density
500degC (kJkg)
0 NaNO3- KNO3 404
1 LiNO3-NaNO3-KNO3 560
2 NaNO3- NaNO2- KNO3 533
3 LiNO3-NaNO
3-KNO
3-MgKN 575
4 LiNO3- NaNO
3- KNO
3- NaNO
2 612
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 595
6 LiNO3-NaNO3-KNO3-KNO2 594
7 LiNO3-KNO3-NaNO2-KNO2 604
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 610
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 649
94
CHAPTER 7
CONCLUSION
The melting points of new molten salts were experimentally determined using DSC
Different from metals the melting point was chosen as the peak temperature rather than onset
temperature of the endothermic peak due to the low thermal conductivity and broad phase
transition range of the molten nitride salt mixture All of the nine new molten salts have melting
points from 89oC to 124
oC which are much lower than current sodium-potassium binary solar
salt Some systems such as salt No1 No7 and No8 have solid phase transformation observed
from the DSC plots It is found that the phase transformations of salt No 7 and No 8 are mainly
contributed to the KNO3-NaNO2 binary system while the small solid transformation peak of salt
No1 is resulted from the combined effect of the KNO3-LiNO3 eutectic binary system involved in
the ternary salt and another binary system which is composed of the rest components The
heating rate of DSC was revealed as a significant parameter for the any endothermic peak
determination When using lower heating rate the thermal resistance between the studied sample
and the furnace will be minimal and the resolution of peak detection will be enhanced
The heat capacities of all the multi-component salts (1 to 9) were determined using DSC
and found varying from 143 to 161 JgK at 350oC The heat capacity in the liquid state
demonstrates linear increase trend as function of temperature On the basis of that the heat
capacity was extrapolated to parabolic trough operating temperature of 500oC Besides heat
capacity data as function of temperature are fit to polynomial equation and thermodynamic
95
properties like enthalpy entropy and Gibbs energies of the compound as function of temperature
are subsequently deduced
Experimental measurements of density of multi-component systems were conducted as
function of temperature in their liquid state In liquid state the density values decrease linearly
as temperature increases The results of those mixtures were compared to the solar salt and
individual constituent salts The comparison demonstrates that the addition of lithium nitrate
lowers the density which is consistent with the observation that lithium nitrate has the lowest
density among all the individual salts in the studied temperature range On the basis of densities
heat capacities and the melting points energy storage density for all the new salts were
calculated and compared to the binary solar salt Among all the new molten salt systems
LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN quinary system (salt 9) presents the largest thermal
energy storage density as well as the gravimetric density values Moreover the larger thermal
energy storage as well as gravimetric storage densities compared to the solar salt indicate the
better energy storage capacities of new salts for solar power generation systems
96
REFERENCES
[1] JF Manwell JG McGowan and AL Rogers Wind Energy Explained-Theory Design and
Application second edition John Wiley and sons Ltd UK 2009
[2] MJ Pasqualetti Morality space and the power of wind-energy landscapes Geographical
Review 90 2000 381-394
[3] DG Fink and HW Beaty Standard Handbook for Electrical Engineers Eleventh Edition
McGraw-Hill New York 1978
[4] R Bertani Geothermal Energy An Overview on Resources and Potential Proceedings of the
International Conference on National Development of Geothermal Energy Use 2009 Slovakia
[5] TA Volk LP Abrahamson EH White E Neuhauser E Gray C Demeter C Lindsey J
Jarnefeld DJ Aneshansley R Pellerin and S Edick Developing a Willow Biomass Crop
Enterprise for Bioenergy and Bioproducts in the United States Proceedings of Bioenergy
2000 October 15-19 2000 Buffalo New York USA
[6] M Asplund N Grevesse and AJ Sauval The new solar abundances-Part I the
observations Communications in Asteroseismology 147 2006 76-79
[7] DRWilliams Sun Fact Sheet NASA 2004
httpnssdcgsfcnasagovplanetaryfactsheetsunfacthtml
[8] U Herrmann Survey of Thermal Energy Storage for Parabolic Trough Power Plants Journal
of Solar Energy Engineering 124 2002 145-152
[9] Rocket Research Company Chemical energy storage for solar thermal conversion SAND79-
8198 Livermore Sandia National Laboratories 1979
97
[10] A Steinfeld and R Palumbo Solar thermochemical process technology Encyclopedia of
Physical Science and Technology 2001 237-256
[11] EA Fletcher Solar thermal processing a review Journal of Solar Energy Engineering
2001 63-74
[12] R W Bradshaw and Nathan P Siegel Molten Nitrate Salt Development for Thermal
Energy Storage in Parabolic Trough Solar Power Systems of the Energy Sustainability 2008
Conference August 10-14 2008 Jacksonville Florida USA
[13] B Kelly H Price D Brosseau and D Kearney Adopting NitrateNitrite Salt Mixtures as
the Heat Transport Fluid in Parabolic Trough Power Plants Proceedings of the Energy
Sustainability 2007 Conference June 27-30 2007 Long Beach CA
[14] H Reilly and G Kolb Evaluation of Molten Salt Power Tower Technology Based on
Experience at Solar Two SAND2001-3674 Sandia National Laboratories 2001
[15] T Wendelin ldquoParabolic Trough VSHOT Optical Characterization in 2005-2006rdquo NREL
wwwnrelgovdocsfy06osti40024pdf
[16] RB Diver C Andraka S Rawlinson V Goldberg and G Thomas The Advanced Dish
Development System Project ASME Proceedings of Solar Forum 2001 Washington DC
[17] S D Odeh G L Morrison and M Behnia Modelling of parabolic trough direct steam
generation solar collectors Solar Energy 62 1998 396-406
[18] V Heinzel H Kungle and M Simon Simulation of a parabolic trough collector ISES
Solar World Congress Harare Zimbabwe 1-10
[19] S D Odeh G L Morrison and M Behnia Modeling of Parabolic Trough Direct
Generation Solar Collectors Solar Energy 62 1998 395-406
[20] Ezzat Optimum Working Fluids for Solar Powered Rankine Cycle Cooling of Buildings
Solar energy 25 1980 235-241
98
[21] R G Reddy Ionic Liquids How well do we know them editorial Journal of Phase
Equilibria and Diffusion 27 2006 210-211
[22] M Zhang and R G Reddy Application of [C4min][Tf2N] Ionic Liquid as Thermal
Storage and Heat Transfer Fluids editor J Weidner ECS Transactions 2 (28) 2007 27-32
[23] M Zhang and R G Reddy Evaluation of Ionic Liquids as Heat Transfer Materials in
Thermal Storage Systems Energy Energy Materials editors F Dogan M Awano D Singh
and B Tuttle ASM International Materials Park Ohio USA MSampT‟07 2007 151-160
[24] R G Reddy Novel Applications of Ionic Liquids in Materials Processing Advanced
Structural and Functional Materials Design 2008 Journal of Physics Conference Series (JPCS)
165 2009 1-6
[25] RW Bradshaw and DE Meeker High-temperature stability of ternary nitrate molten
salts for solar thermal energy systems Solar Energy Materials 21 1990 51-60
[26] AS Trunin Designing and investigations of salt systems for solar energy utilization
Utilization of sun and other radiation sources in materials research Kiev Naukova Dumka 1983
p 228-38
[27] D J Rogers and G J Janz Melting-crystallization and premelting properties of sodium
nitrate-potassium nitrate Enthalpies and heat capacities Journal of Chemical and Engineering
Data 27 1982 424-428
[28] D Kearney U Herrmann P Nava and B Kelly Assessment of a molten salt heat transfer
fluid in a parabolic trough solar field Journal of Solar Energy Engineering 125 2003 170-176
[29] Q Peng J Ding X Wei J Yang and X Yang The preparation and properties of multi-
component molten salts Applied Energy 87 2010 2812-2817
[30] E M Levin C R Robbins and H F McMordie Phase Diagrams for Ceramists American
Ceramic Society 1964
[31] J C Oxley J L Smith E Rogers and M Yu Ammonium nitrate thermal stability and
explosivity modifiers Thermochimica Acta 384 2002 23-45
99
[32] LG Marianowski and HC Maru Latent heat thermal energy storage systems above
4508oC Proceedings of 12th intersociety energy conversion engineering conference 1977 55-
66
[33] HC Maru JF Dullea A Kardas L Paul LG Marianowski E Ong et al Molten salts
energy storage systems Chicago Final Report of the Institute of Gas Technology 1978
[34] WM Philips and JW Stears Advanced latent heat of fusion thermal energy storage for
solar power stations Proceedings of 20th intersociety energy conversion engineering conference
2 1985 384-391
[35] KE Mayo Heat source systems USA Patent 3605720 1971
[36] JI Eichelberger and HD Gillman Investigation of metal fluoride thermal energy storage
material Proceedings of 12th intersociety energy conversion engineering conference 1977 567-
574
[37] GR Heidenreich and MB Parekh Thermal energy storage for organic Rankine cycle solar
dynamic space power systems Proceedings of 21st intersociety energy conversion engineering
conference 2 1986 791-797
[38] IK Garkushin AC Trunin TT Miftakhov and MA Dibirov Salt heat storage
composition USSR Patent 1036734 1983
[39] W M Philips and J W Stears Advanced latent heat of fusion thermal energy storage for
solar power stations In Proceedings of 20th intersociety energy conversion engineering
conference 2 1985 384-391
[40] Y Takahashi M Kamimoto Y Abe R Sakamoto K Kanari and T Ozawa Investigation
of latent heat-thermal energy storage materials IV Thermoanalitical evaluation of binary eutectic
mixtures of NaOH with LiOH or KOH Thermochim Acta 121 1987 193-202
[41] C E Birchenall and A F Riechman Heat storage in eutectic alloys Metall Trans A
11A(8) 1980 1415-1420
100
[42] Y Takahashi R Sakamoto and M Kamimoto Heat capacities and latent heats of LiNO3
NaNO3 and KNO3 International Journal of Thermophysics 9(6) 1988 1081-1090
[43] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate Mixtures
Journal of Chemical Engineering Data 8(3) 1963 469
[44] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical Engineering Data 6 (4) 1961 493
[45] GF Petersen WA Ewing and G P Smith Densities of Some Salt Mixtures Journal of
Chemical Engineering Data 6 (4) 1961 540
[46] G J Janz and M R Lorenz Precise Measurement of Density and Surface Tension at
Temperatures up to 1000degC in One Apparatus Review of Scientific Instruments 31 (1) 1960
18-23
[47] G J Janz C B Allen N P Bansal R M Murphy and R P Tomkins Physical Properties
Data Compilations Relevant to Energy Storage II Molten Salts Data on Single and Multi-
Component Salt Systems National Bureau of Standards NSRDS-NBS 61 Part II April 1979
[48] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation Equations
for Critically Evaluated Density Surface Tension Electrical Conductance and Viscosity Data
Journal of Physical and Chemical Reference Data 17 1988 2
[49] A T Ward and G J Janz Molten Carbonate Electrolytes Electiral Conductance Density
and Surface Tension of Binary and Ternary Eleclrochimica Acta 10 1965 849-857
[50] Y Takahashi R Sakamoto and MKamimoto Heat Capacities and Latent Heat of LiNO3
NaNO3 amp KNO3 International Journal of Thermophysics 9 1998 1081-1090
[51] R W Carling Heat capacities of NaNO3 and KNO3 up to 800 K Thermochimica Acta 60
1983 265-275
[52] Y Takahashi Latent heat measurement by DSC with sapphire as standard material
Thermochim Acta 88(1) 1985 199-204
101
[53] GW Hohne W Hemminger and HJ Flammersheim Differential Scanning Calorimetry
Springer-Verlag Berlin 1996
[54] W Hemminger and G Hohne Calorimetry Fundamentals and Practice Verlag Weinheim
1984
[55] M Merzlyakov and C Schick Thermal conductivity from dynamic response of DSC
Thermochimica Acta 377 2001 183-191
[56] T Kousksou A Jamil S Gibout and Y Zeraouli Thermal analysis of phase change
emulsion Journal of Thermal Analysis and Calorimetry 96 2009 841-852
[57] A Jamil T Kousksou K El Omari Y Zeraouli and Y Le Guer Heat transfer in salt
solutions enclosed in DSC cells Thermochimica Acta 507-508 2010 15-20
[58] MJ Richardson Quantitative aspects of differential scanning calorimetry Thermochimica
Acta 300 1997 15-28
[59] S Rudtsch Uncertainty of heat capacity measurements with differential scanning
calorimeters Thermochimica Acta 382 2002 17-25
[60] M J Maeso and J Largo The phase diagram of LiNO3-NaNO3 and LiNO3-KNO3 the
behavior of liquid mixtures Thermochimica Acta 223 (1993) 145-156
[61] O J Kleppa A new twin high-temperature reaction calorimeter The heats of mixing in
liquid sodium-potassium nitrates Journal of Physical Chemistry 64(12) (1960) 1937-1940
[62] G W H Hhne H K Cammenga W Eysel E Gmelin and W Hemminger The
Temperature Calibration of Scanning Calorimeters Thermochimica Acta 160 1990 1-12
[63] L B Pankratz Thermodynamic Properties of Carbides Nitrides and Other Selected
Substances U S Bureau of Mines Bulletin 696 1994
[64] M Zhang and R G Reddy Thermodynamic properties of C4mim[Tf2N] ionic liquids 0 2
2010 71-76
102
[65] D Mantha T Wang and R G Reddy Thermodynamic Modeling of Eutectic Point in the
LiNO3-NaNO3-KNO3 Ternary System Journal of Phase Equilibria and Diffusion 2011
(accepted)
[66] R G Reddy T Wang and D Mantha Determination of thermodynamic properties of
2KNO3Mg(NO3)2 Thermochimica Acta 2011 (submitted)
[67] T Wang D Mantha and R G Reddy Thermal stability of new LiNO3-NaNO3-KNO3
ternary salt for thermal energy storage system (in preparation)
[68] G D Carvalho E Frollini and W N D Santos Thermal conductivity of polymers by hot-
wire method J Appl Poly Sci 62 (1996) 2281-2285
[69] H Bloom A Doroszkowski and S B Tricklebank Molten salt mixtures IX The thermal
conductivities of molten nitrate systems Aus J Chem 18(8) (1965) 1171-1176
[70] A G Turnbull Thermal conductivity of molten salts Aus J Appl Sci 12 (1961) 30-41
[71] L R White and H T Davis Thermal conductivity of molten alkali nitrates J Chem Phys
47(1967) 5433-5439
[72] M V Peralta-Martinez M J Assael M J Dix L Karagiannidis and W A Wakeham A
Novel Instrument for the Measurement of the Thermal Conductivity of Molten Metal Part1
Instrument‟s Description Int J Thermophysics 27 (2006) 353-375
[73] Y Tada M Harada M Tanlgakl and W Eguchl Laser Flash Method for Measuring
Thermal Conductivity of Liquids Application to Molten Salts Industrial and Engineering
Chemistry Fundamentals 20 1981 333- 336
[74] M V Smirnov V A Khokhlov and E S Filatov Thermal conductivity of molten alkali
halides and their mixtures Electrochimica Acta 32 (1986) 1019-1026
[75] E Marti E Kaisersberger and W D Emmerich NEW ASPECTS OF THERMAL
ANALYSIS Part I Resolution of DSC and means for its optimization Journal of Thermal
Analysis and Calorimetry 77 2004 905-934
103
[76] E Marti E Kaisersberger G Kaiser and WY Ma Netzsch Annual 2000
bdquoThermoanalytical Characterization of Pharmaceuticals‟ Netzsch-Geraumltebau GmbH D-95100
SelbBavaria
[77] P J van Ekeren C M Holl and A J Witteveen A comparative test of differential
scanning calorimeters Journal of Thermal Analysis and Calorimetry 49 1997 1105-1114
[78] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation
Equations for Critically Evaluated Density Surface Tension Electrical Conductance and
Viscosity Data Journal of Physical and Chemical Reference Data 17 1988 1
[79] G F Petersen W A Ewing and G P Smith ldquoDensities of Some Salt Mixturesrdquo Journal of
Chemical and Engineering Data 6 1961 540
[80] P M Nasch and S G Steinemann Density and Thermal Expansion of Molten Manganese
Iron Nickel Copper Aluminum and Tin by Means of the Gamma-Ray Attenuation Technique
Physics and Chemistry of Liquids 29 1995 43-58
[81] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical and Engineering Data 6 1961 493-496
[82] D A Nissen Thermophysical Properties of the Equimolar Mixture NaNO3-KNO3 from
300degC to 600degC Journal of Chemical and Engineering Data 27 1982 269-273
[83] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate
Mixtures Journal of Chemical and Engineering Data 8 1963 469
104
APPENDIX
Appendix A
Table A1 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in solid state
(29815-40315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 342 1290 417 -025
299 027 008 000 343 1317 426 -026
300 059 018 000 344 1345 436 -027
301 091 028 000 345 1372 445 -028
302 123 037 000 346 1399 455 -029
303 154 047 000 347 1427 464 -031
304 186 056 000 348 1454 474 -032
305 217 066 000 349 1481 483 -033
306 248 076 000 350 1508 493 -035
307 279 085 000 351 1535 503 -036
308 310 095 -001 352 1562 512 -038
309 340 104 -001 353 1589 522 -039
310 371 114 -001 354 1616 532 -041
311 401 123 -001 355 1643 541 -042
312 432 133 -002 356 1670 551 -044
313 462 142 -002 357 1697 561 -045
314 492 152 -002 358 1724 570 -047
315 521 161 -003 359 1751 580 -048
316 551 171 -003 360 1777 590 -050
317 581 180 -004 361 1804 600 -052
318 610 190 -004 362 1831 610 -053
319 640 199 -005 363 1858 619 -055
320 669 209 -005 364 1885 629 -057
105
321 698 218 -006 365 1911 639 -059
322 727 228 -007 366 1938 649 -060
323 756 237 -007 367 1965 659 -062
324 785 246 -008 368 1992 669 -064
325 814 256 -009 369 2018 679 -066
326 842 265 -009 370 2045 689 -068
327 871 275 -010 371 2072 699 -070
328 899 284 -011 372 2098 709 -072
329 928 294 -012 373 2125 719 -074
330 956 303 -012 374 2152 729 -076
331 984 313 -013 375 2179 739 -078
332 1012 322 -014 376 2205 750 -080
333 1041 331 -015 377 2232 760 -082
334 1069 341 -016 378 2259 770 -084
335 1096 350 -017 379 2286 780 -086
336 1124 360 -018 380 2312 791 -088
337 1152 369 -019 381 2339 801 -090
338 1180 379 -020 382 2366 811 -093
339 1207 388 -021 383 2393 822 -095
340 1235 398 -022 384 2420 832 -097
341 1263 407 -023 38415 2424 834 -097
Table A2 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in liquid state
(40315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
40315 4287 1565 -163 514 7070 2838 -796
404 4310 1575 -167 515 7094 2850 -803
405 4337 1585 -171 516 7117 2863 -810
406 4363 1596 -175 517 7141 2875 -817
407 4390 1607 -180 518 7165 2887 -824
408 4417 1618 -184 519 7188 2899 -831
409 4443 1629 -189 520 7212 2911 -839
410 4470 1640 -193 521 7235 2924 -846
411 4496 1651 -197 522 7259 2936 -853
412 4523 1662 -202 523 7282 2948 -860
106
413 4549 1672 -206 524 7306 2960 -868
414 4576 1683 -211 525 7329 2973 -875
415 4602 1694 -216 526 7352 2985 -882
416 4629 1705 -220 527 7376 2997 -890
417 4655 1716 -225 528 7399 3010 -897
418 4681 1727 -230 529 7422 3022 -904
419 4708 1738 -234 530 7446 3034 -912
420 4734 1749 -239 531 7469 3047 -919
421 4760 1760 -244 532 7492 3059 -927
422 4786 1771 -249 533 7516 3071 -934
423 4813 1782 -253 534 7539 3084 -942
424 4839 1793 -258 535 7562 3096 -949
425 4865 1804 -263 536 7585 3109 -957
426 4891 1816 -268 537 7608 3121 -965
427 4917 1827 -273 538 7632 3134 -972
428 4943 1838 -278 539 7655 3146 -980
429 4969 1849 -283 540 7678 3158 -988
430 4995 1860 -288 541 7701 3171 -995
431 5021 1871 -293 542 7724 3183 -1003
432 5046 1882 -298 543 7747 3196 -1011
433 5072 1894 -303 544 7770 3208 -1018
434 5098 1905 -308 545 7793 3221 -1026
435 5124 1916 -313 546 7816 3233 -1034
436 5149 1927 -318 547 7839 3246 -1042
437 5175 1938 -323 548 7862 3259 -1050
438 5201 1950 -328 549 7885 3271 -1058
439 5226 1961 -334 550 7908 3284 -1066
440 5252 1972 -339 551 7931 3296 -1073
441 5278 1983 -344 552 7953 3309 -1081
442 5303 1995 -349 553 7976 3322 -1089
443 5329 2006 -355 554 7999 3334 -1097
444 5354 2017 -360 555 8022 3347 -1105
445 5380 2028 -365 556 8045 3359 -1113
446 5405 2040 -371 557 8067 3372 -1121
447 5430 2051 -376 558 8090 3385 -1130
448 5456 2062 -382 559 8113 3398 -1138
449 5481 2074 -387 560 8136 3410 -1146
450 5506 2085 -393 561 8158 3423 -1154
451 5532 2097 -398 562 8181 3436 -1162
452 5557 2108 -404 563 8204 3448 -1170
107
453 5582 2119 -409 564 8226 3461 -1178
454 5607 2131 -415 565 8249 3474 -1187
455 5633 2142 -421 566 8271 3487 -1195
456 5658 2154 -426 567 8294 3499 -1203
457 5683 2165 -432 568 8317 3512 -1212
458 5708 2177 -438 569 8339 3525 -1220
459 5733 2188 -443 570 8362 3538 -1228
460 5758 2200 -449 571 8384 3551 -1237
461 5783 2211 -455 572 8407 3564 -1245
462 5808 2223 -461 573 8429 3576 -1253
463 5833 2234 -466 574 8452 3589 -1262
464 5858 2246 -472 575 8474 3602 -1270
465 5883 2257 -478 576 8496 3615 -1279
466 5907 2269 -484 577 8519 3628 -1287
467 5932 2280 -490 578 8541 3641 -1296
468 5957 2292 -496 579 8564 3654 -1304
469 5982 2304 -502 580 8586 3667 -1313
470 6007 2315 -508 581 8608 3680 -1322
471 6031 2327 -514 582 8631 3693 -1330
472 6056 2339 -520 583 8653 3706 -1339
473 6081 2350 -526 584 8675 3719 -1348
474 6105 2362 -532 585 8697 3732 -1356
475 6130 2373 -538 586 8720 3745 -1365
476 6155 2385 -544 587 8742 3758 -1374
477 6179 2397 -551 588 8764 3771 -1382
478 6204 2409 -557 589 8786 3784 -1391
479 6228 2420 -563 590 8808 3797 -1400
480 6253 2432 -569 591 8831 3810 -1409
481 6277 2444 -575 592 8853 3823 -1418
482 6301 2456 -582 593 8875 3836 -1426
483 6326 2467 -588 594 8897 3849 -1435
484 6350 2479 -594 595 8919 3863 -1444
485 6375 2491 -601 596 8941 3876 -1453
486 6399 2503 -607 597 8963 3889 -1462
487 6423 2515 -614 598 8985 3902 -1471
488 6448 2526 -620 599 9007 3915 -1480
489 6472 2538 -626 600 9029 3928 -1489
490 6496 2550 -633 601 9051 3942 -1498
491 6520 2562 -639 602 9073 3955 -1507
492 6544 2574 -646 603 9095 3968 -1516
108
493 6569 2586 -653 604 9117 3981 -1525
494 6593 2598 -659 605 9139 3994 -1535
495 6617 2610 -666 606 9161 4008 -1544
496 6641 2621 -672 607 9183 4021 -1553
497 6665 2633 -679 608 9205 4034 -1562
498 6689 2645 -686 609 9226 4048 -1571
499 6713 2657 -692 610 9248 4061 -1581
500 6737 2669 -699 611 9270 4074 -1590
501 6761 2681 -706 612 9292 4088 -1599
502 6785 2693 -713 613 9314 4101 -1608
503 6809 2705 -719 614 9335 4114 -1618
504 6833 2717 -726 615 9357 4128 -1627
505 6856 2729 -733 616 9379 4141 -1636
506 6880 2741 -740 617 9401 4154 -1646
507 6904 2754 -747 618 9422 4168 -1655
508 6928 2766 -754 619 9444 4181 -1665
509 6952 2778 -761 620 9466 4195 -1674
510 6975 2790 -768 621 9487 4208 -1684
511 6999 2802 -775 622 9509 4222 -1693
512 7023 2814 -782 623 9531 4235 -1703
513 7047 2826 -789 62315 9534 4237 -1704
109
Appendix B
Table B1 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(29815-39215K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 347 1233 382 -046
299 022 006 000 348 1258 390 -048
300 049 014 -001 349 1283 398 -049
301 075 022 -001 350 1307 406 -051
302 101 029 -001 351 1332 415 -053
303 127 037 -002 352 1356 423 -054
304 153 044 -002 353 1381 431 -056
305 179 052 -003 354 1405 440 -058
306 205 059 -003 355 1430 448 -060
307 230 067 -004 356 1455 456 -061
308 256 075 -004 357 1479 465 -063
309 282 082 -005 358 1504 473 -065
310 308 090 -005 359 1528 482 -067
311 333 098 -006 360 1553 490 -069
312 359 105 -007 361 1577 498 -071
313 384 113 -007 362 1602 507 -073
314 410 121 -008 363 1626 515 -075
315 435 128 -009 364 1651 524 -077
316 461 136 -010 365 1675 533 -079
317 486 144 -010 366 1700 541 -081
318 511 151 -011 367 1724 550 -083
319 537 159 -012 368 1749 558 -085
320 562 167 -013 369 1773 567 -087
321 587 175 -014 370 1798 576 -089
322 612 182 -015 371 1822 584 -092
323 637 190 -016 372 1847 593 -094
324 663 198 -017 373 1871 602 -096
325 688 206 -018 374 1896 611 -098
326 713 214 -019 375 1920 620 -100
327 738 222 -020 376 1945 628 -103
328 763 229 -021 377 1969 637 -105
329 788 237 -022 378 1994 646 -107
110
330 813 245 -023 379 2018 655 -110
331 838 253 -024 380 2043 664 -112
332 863 261 -025 381 2068 673 -115
333 887 269 -027 382 2092 682 -117
334 912 277 -028 383 2117 691 -120
335 937 285 -029 384 2141 700 -122
336 962 293 -030 385 2166 709 -125
337 987 301 -032 386 2191 718 -127
338 1011 309 -033 387 2215 727 -130
339 1036 317 -034 388 2240 737 -132
340 1061 325 -036 389 2265 746 -135
341 1086 333 -037 390 2289 755 -138
342 1110 341 -039 391 2314 764 -140
343 1135 349 -040 392 2339 774 -143
344 1160 357 -042 39215 2342 775 -144
345 1184 365 -043
Table B2 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(41315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
414 3280 1149 -209 520 5608 2235 -682
415 3302 1158 -212 521 5630 2246 -687
416 3325 1167 -216 522 5651 2257 -693
417 3348 1177 -219 523 5672 2268 -698
418 3370 1186 -223 524 5694 2279 -704
419 3393 1196 -226 525 5715 2290 -710
420 3416 1205 -229 526 5736 2302 -716
421 3438 1215 -233 527 5757 2313 -721
422 3461 1224 -236 528 5779 2324 -727
423 3483 1234 -240 529 5800 2335 -733
424 3506 1243 -243 530 5821 2347 -739
425 3529 1253 -247 531 5842 2358 -745
426 3551 1263 -250 532 5864 2369 -750
427 3574 1272 -254 533 5885 2380 -756
428 3596 1282 -257 534 5906 2392 -762
429 3619 1291 -261 535 5927 2403 -768
111
430 3641 1301 -265 536 5948 2414 -774
431 3663 1311 -268 537 5970 2426 -780
432 3686 1320 -272 538 5991 2437 -786
433 3708 1330 -276 539 6012 2449 -792
434 3731 1340 -279 540 6033 2460 -798
435 3753 1350 -283 541 6054 2471 -804
436 3775 1359 -287 542 6075 2483 -810
437 3798 1369 -291 543 6096 2494 -816
438 3820 1379 -294 544 6118 2506 -822
439 3842 1389 -298 545 6139 2517 -828
440 3865 1398 -302 546 6160 2529 -835
441 3887 1408 -306 547 6181 2540 -841
442 3909 1418 -310 548 6202 2552 -847
443 3932 1428 -314 549 6223 2563 -853
444 3954 1438 -318 550 6244 2575 -859
445 3976 1448 -322 551 6265 2586 -866
446 3998 1458 -326 552 6286 2598 -872
447 4021 1468 -330 553 6307 2610 -878
448 4043 1477 -334 554 6328 2621 -884
449 4065 1487 -338 555 6349 2633 -891
450 4087 1497 -342 556 6370 2645 -897
451 4109 1507 -346 557 6391 2656 -904
452 4131 1517 -350 558 6412 2668 -910
453 4154 1527 -354 559 6433 2680 -916
454 4176 1537 -358 560 6454 2691 -923
455 4198 1547 -363 561 6475 2703 -929
456 4220 1557 -367 562 6496 2715 -936
457 4242 1568 -371 563 6517 2727 -942
458 4264 1578 -375 564 6538 2738 -949
459 4286 1588 -380 565 6559 2750 -955
460 4308 1598 -384 566 6580 2762 -962
461 4330 1608 -388 567 6600 2774 -969
462 4352 1618 -393 568 6621 2786 -975
463 4374 1628 -397 569 6642 2798 -982
464 4396 1639 -401 570 6663 2810 -988
465 4418 1649 -406 571 6684 2821 -995
466 4440 1659 -410 572 6705 2833 -1002
467 4462 1669 -415 573 6726 2845 -1009
468 4484 1680 -419 574 6747 2857 -1015
469 4506 1690 -424 575 6767 2869 -1022
112
470 4528 1700 -428 576 6788 2881 -1029
471 4550 1710 -433 577 6809 2893 -1036
472 4572 1721 -437 578 6830 2905 -1042
473 4593 1731 -442 579 6851 2917 -1049
474 4615 1741 -446 580 6871 2929 -1056
475 4637 1752 -451 581 6892 2941 -1063
476 4659 1762 -456 582 6913 2953 -1070
477 4681 1773 -460 583 6934 2966 -1077
478 4703 1783 -465 584 6954 2978 -1084
479 4724 1793 -470 585 6975 2990 -1091
480 4746 1804 -474 586 6996 3002 -1098
481 4768 1814 -479 587 7017 3014 -1105
482 4790 1825 -484 588 7037 3026 -1112
483 4812 1835 -489 589 7058 3038 -1119
484 4833 1846 -494 590 7079 3051 -1126
485 4855 1856 -498 591 7100 3063 -1133
486 4877 1867 -503 592 7120 3075 -1140
487 4898 1877 -508 593 7141 3087 -1147
488 4920 1888 -513 594 7162 3100 -1154
489 4942 1899 -518 595 7182 3112 -1162
490 4963 1909 -523 596 7203 3124 -1169
491 4985 1920 -528 597 7224 3137 -1176
492 5007 1930 -533 598 7244 3149 -1183
493 5028 1941 -538 599 7265 3161 -1190
494 5050 1952 -543 600 7285 3174 -1198
495 5072 1962 -548 601 7306 3186 -1205
496 5093 1973 -553 602 7327 3198 -1212
497 5115 1984 -558 603 7347 3211 -1220
498 5136 1995 -563 604 7368 3223 -1227
499 5158 2005 -568 605 7389 3236 -1234
500 5180 2016 -574 606 7409 3248 -1242
501 5201 2027 -579 607 7430 3261 -1249
502 5223 2038 -584 608 7450 3273 -1257
503 5244 2049 -589 609 7471 3286 -1264
504 5266 2059 -595 610 7491 3298 -1272
505 5287 2070 -600 611 7512 3311 -1279
506 5309 2081 -605 612 7532 3323 -1287
507 5330 2092 -610 613 7553 3336 -1294
508 5352 2103 -616 614 7573 3348 -1302
509 5373 2114 -621 615 7594 3361 -1309
113
510 5394 2125 -627 616 7615 3374 -1317
511 5416 2136 -632 617 7635 3386 -1325
512 5437 2147 -637 618 7656 3399 -1332
513 5459 2158 -643 619 7676 3412 -1340
514 5480 2169 -648 620 7696 3424 -1348
515 5502 2180 -654 621 7717 3437 -1355
516 5523 2191 -659 622 7737 3450 -1363
517 5544 2202 -665 623 7758 3462 -1371
518 5566 2213 -670 62315 7761 3464 -1372
114
Appendix C
Table C1 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in solid
state (29815-36415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 333 1937 611 -034
299 048 014 000 334 1992 629 -036
300 104 031 000 335 2047 647 -038
301 160 048 000 336 2102 666 -040
302 216 065 000 337 2156 684 -042
303 272 082 -001 338 2211 703 -045
304 329 099 -001 339 2266 721 -047
305 385 116 -001 340 2321 740 -049
306 441 133 -002 341 2375 758 -052
307 496 150 -002 342 2430 777 -054
308 552 167 -003 343 2485 796 -056
309 608 185 -003 344 2539 815 -059
310 664 202 -004 345 2594 833 -062
311 720 219 -005 346 2648 852 -064
312 776 236 -006 347 2703 871 -067
313 831 254 -006 348 2757 890 -070
314 887 271 -007 349 2812 909 -072
315 942 289 -008 350 2866 928 -075
316 998 306 -009 351 2921 947 -078
317 1054 324 -010 352 2975 966 -081
318 1109 341 -011 353 3029 985 -084
319 1164 359 -012 354 3084 1004 -087
320 1220 377 -014 355 3138 1024 -090
321 1275 395 -015 356 3192 1043 -094
322 1331 412 -016 357 3246 1062 -097
323 1386 430 -018 358 3300 1082 -100
324 1441 448 -019 359 3355 1101 -103
325 1496 466 -020 360 3409 1120 -107
326 1552 484 -022 361 3463 1140 -110
327 1607 502 -024 362 3517 1159 -114
328 1662 520 -025 363 3571 1179 -117
329 1717 538 -027 364 3625 1199 -121
115
330 1772 556 -029 36415 3633 1202 -121
331 1827 574 -030
332 1882 593 -032
Table C2 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in liquid
state (42115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
42115 7428 2673 -455 523 11788 4725 -1440
422 7468 2690 -461 524 11827 4745 -1452
423 7515 2710 -468 525 11866 4766 -1464
424 7562 2730 -476 526 11904 4786 -1476
425 7608 2750 -484 527 11943 4807 -1488
426 7655 2770 -491 528 11982 4827 -1500
427 7702 2790 -499 529 12021 4847 -1512
428 7748 2810 -507 530 12059 4868 -1524
429 7795 2830 -514 531 12098 4888 -1536
430 7841 2849 -522 532 12137 4909 -1548
431 7887 2869 -530 533 12175 4929 -1560
432 7933 2889 -538 534 12213 4950 -1572
433 7979 2909 -546 535 12252 4970 -1584
434 8025 2929 -554 536 12290 4991 -1597
435 8071 2949 -562 537 12328 5011 -1609
436 8117 2969 -570 538 12366 5032 -1621
437 8163 2989 -578 539 12404 5052 -1634
438 8208 3009 -586 540 12442 5073 -1646
439 8254 3029 -595 541 12480 5093 -1659
440 8299 3049 -603 542 12518 5114 -1671
441 8345 3069 -611 543 12556 5134 -1684
442 8390 3089 -620 544 12594 5155 -1696
443 8435 3109 -628 545 12632 5175 -1709
444 8480 3129 -636 546 12669 5196 -1721
445 8525 3149 -645 547 12707 5217 -1734
446 8570 3169 -654 548 12745 5237 -1747
116
447 8615 3189 -662 549 12782 5258 -1760
448 8659 3209 -671 550 12820 5278 -1772
449 8704 3229 -679 551 12857 5299 -1785
450 8748 3249 -688 552 12894 5319 -1798
451 8793 3269 -697 553 12932 5340 -1811
452 8837 3289 -706 554 12969 5361 -1824
453 8881 3309 -715 555 13006 5381 -1837
454 8926 3329 -724 556 13043 5402 -1850
455 8970 3349 -732 557 13080 5422 -1863
456 9014 3369 -741 558 13117 5443 -1876
457 9058 3389 -750 559 13154 5464 -1889
458 9102 3409 -760 560 13191 5484 -1902
459 9145 3429 -769 561 13228 5505 -1916
460 9189 3449 -778 562 13264 5526 -1929
461 9233 3469 -787 563 13301 5546 -1942
462 9276 3489 -796 564 13338 5567 -1956
463 9319 3509 -806 565 13374 5588 -1969
464 9363 3529 -815 566 13411 5608 -1982
465 9406 3549 -824 567 13447 5629 -1996
466 9449 3570 -834 568 13484 5650 -2009
467 9492 3590 -843 569 13520 5670 -2023
468 9535 3610 -853 570 13557 5691 -2036
469 9578 3630 -862 571 13593 5712 -2050
470 9621 3650 -872 572 13629 5732 -2063
471 9664 3670 -882 573 13665 5753 -2077
472 9707 3690 -891 574 13701 5774 -2091
473 9749 3710 -901 575 13737 5795 -2104
474 9792 3731 -911 576 13773 5815 -2118
475 9834 3751 -921 577 13809 5836 -2132
476 9877 3771 -930 578 13845 5857 -2146
477 9919 3791 -940 579 13881 5877 -2160
478 9961 3811 -950 580 13917 5898 -2174
479 10004 3831 -960 581 13953 5919 -2188
480 10046 3852 -970 582 13988 5940 -2202
481 10088 3872 -980 583 14024 5960 -2216
482 10130 3892 -990 584 14060 5981 -2230
483 10171 3912 -1001 585 14095 6002 -2244
484 10213 3932 -1011 586 14131 6023 -2258
485 10255 3953 -1021 587 14166 6044 -2272
486 10297 3973 -1031 588 14201 6064 -2286
117
487 10338 3993 -1042 589 14237 6085 -2300
488 10380 4013 -1052 590 14272 6106 -2315
489 10421 4034 -1062 591 14307 6127 -2329
490 10462 4054 -1073 592 14342 6148 -2343
491 10504 4074 -1083 593 14378 6168 -2358
492 10545 4094 -1094 594 14413 6189 -2372
493 10586 4114 -1104 595 14448 6210 -2386
494 10627 4135 -1115 596 14483 6231 -2401
495 10668 4155 -1126 597 14518 6252 -2415
496 10709 4175 -1136 598 14552 6273 -2430
497 10750 4196 -1147 599 14587 6293 -2444
498 10791 4216 -1158 600 14622 6314 -2459
499 10831 4236 -1169 601 14657 6335 -2474
500 10872 4256 -1179 602 14692 6356 -2488
501 10912 4277 -1190 603 14726 6377 -2503
502 10953 4297 -1201 604 14761 6398 -2518
503 10993 4317 -1212 605 14795 6419 -2533
504 11034 4338 -1223 606 14830 6439 -2547
505 11074 4358 -1234 607 14864 6460 -2562
506 11114 4378 -1245 608 14899 6481 -2577
507 11154 4399 -1257 609 14933 6502 -2592
508 11194 4419 -1268 610 14967 6523 -2607
509 11234 4439 -1279 611 15002 6544 -2622
510 11274 4460 -1290 612 15036 6565 -2637
511 11314 4480 -1302 613 15070 6586 -2652
512 11354 4500 -1313 614 15104 6607 -2667
513 11394 4521 -1324 615 15138 6628 -2682
514 11433 4541 -1336 616 15172 6649 -2697
515 11473 4562 -1347 617 15206 6670 -2713
516 11513 4582 -1359 618 15240 6691 -2728
517 11552 4602 -1370 619 15274 6712 -2743
518 11591 4623 -1382 620 15308 6733 -2758
519 11631 4643 -1393 621 15342 6754 -2774
520 11670 4664 -1405 622 15375 6774 -2789
521 11709 4684 -1417 623 15409 6795 -2804
522 11748 4704 -1428 62315 15414 6799 -2807
118
Appendix D
Table D1 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in solid state
(29815-36315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
299 021 006 000 333 867 277 -012
300 047 014 000 334 891 285 -012
301 072 022 000 335 916 293 -013
302 097 029 000 336 940 302 -014
303 122 037 000 337 964 310 -015
304 147 045 000 338 989 318 -016
305 172 053 000 339 1013 327 -017
306 197 060 000 340 1037 335 -018
307 223 068 000 341 1061 343 -019
308 248 076 000 342 1085 352 -019
309 273 084 000 343 1109 360 -020
310 298 092 -001 344 1134 369 -021
311 323 099 -001 345 1158 377 -022
312 348 107 -001 346 1182 385 -024
313 373 115 -001 347 1206 394 -025
314 398 123 -002 348 1230 402 -026
315 423 131 -002 349 1254 411 -027
316 447 139 -002 350 1277 419 -028
317 472 147 -003 351 1301 428 -029
318 497 155 -003 352 1325 436 -030
319 522 163 -003 353 1349 445 -032
320 547 171 -004 354 1373 453 -033
321 572 179 -004 355 1396 462 -034
322 596 187 -005 356 1420 470 -035
323 621 195 -005 357 1444 479 -037
324 646 203 -006 358 1467 487 -038
325 670 211 -006 359 1491 496 -039
326 695 220 -007 360 1514 504 -041
327 720 228 -008 361 1538 513 -042
328 744 236 -008 362 1561 522 -043
329 769 244 -009 363 1584 530 -045
330 793 252 -010 36315 1588 532 -045
119
331 818 260 -010
Table D2 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in liquid
state (38115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
38115 2281 765 -104 503 5639 2242 -594
382 2307 775 -106 504 5664 2255 -600
383 2338 787 -109 505 5689 2267 -606
384 2369 798 -111 506 5713 2280 -611
385 2399 810 -113 507 5738 2292 -617
386 2430 822 -116 508 5763 2305 -623
387 2460 834 -118 509 5787 2317 -629
388 2491 846 -121 510 5812 2330 -634
389 2521 857 -123 511 5836 2342 -640
390 2551 869 -126 512 5861 2355 -646
391 2582 881 -128 513 5885 2367 -652
392 2612 893 -131 514 5910 2380 -658
393 2642 905 -134 515 5934 2392 -664
394 2672 917 -136 516 5959 2405 -670
395 2702 928 -139 517 5983 2417 -676
396 2732 940 -142 518 6007 2430 -682
397 2762 952 -144 519 6032 2443 -688
398 2792 964 -147 520 6056 2455 -694
399 2821 976 -150 521 6080 2468 -700
400 2851 988 -153 522 6104 2480 -706
401 2881 999 -156 523 6128 2493 -712
402 2910 1011 -159 524 6152 2506 -718
403 2940 1023 -162 525 6176 2518 -724
404 2969 1035 -164 526 6200 2531 -731
405 2999 1047 -167 527 6224 2544 -737
406 3028 1059 -170 528 6248 2556 -743
407 3057 1071 -174 529 6272 2569 -749
408 3087 1083 -177 530 6296 2581 -756
120
409 3116 1095 -180 531 6320 2594 -762
410 3145 1107 -183 532 6344 2607 -768
411 3174 1119 -186 533 6368 2619 -775
412 3203 1130 -189 534 6391 2632 -781
413 3232 1142 -192 535 6415 2645 -787
414 3261 1154 -196 536 6439 2657 -794
415 3290 1166 -199 537 6462 2670 -800
416 3319 1178 -202 538 6486 2683 -807
417 3347 1190 -206 539 6510 2696 -813
418 3376 1202 -209 540 6533 2708 -820
419 3405 1214 -212 541 6557 2721 -826
420 3433 1226 -216 542 6580 2734 -833
421 3462 1238 -219 543 6604 2746 -839
422 3490 1250 -223 544 6627 2759 -846
423 3519 1262 -226 545 6650 2772 -853
424 3547 1274 -230 546 6674 2785 -859
425 3575 1286 -233 547 6697 2797 -866
426 3604 1298 -237 548 6720 2810 -873
427 3632 1310 -240 549 6744 2823 -879
428 3660 1322 -244 550 6767 2836 -886
429 3688 1334 -248 551 6790 2848 -893
430 3716 1346 -251 552 6813 2861 -900
431 3744 1358 -255 553 6836 2874 -907
432 3772 1371 -259 554 6860 2887 -913
433 3800 1383 -263 555 6883 2900 -920
434 3828 1395 -267 556 6906 2912 -927
435 3856 1407 -270 557 6929 2925 -934
436 3883 1419 -274 558 6952 2938 -941
437 3911 1431 -278 559 6975 2951 -948
438 3939 1443 -282 560 6998 2964 -955
439 3966 1455 -286 561 7020 2976 -962
440 3994 1467 -290 562 7043 2989 -969
441 4021 1479 -294 563 7066 3002 -976
442 4049 1491 -298 564 7089 3015 -983
443 4076 1504 -302 565 7112 3028 -990
444 4103 1516 -306 566 7134 3041 -997
445 4131 1528 -310 567 7157 3054 -1005
446 4158 1540 -314 568 7180 3066 -1012
447 4185 1552 -319 569 7203 3079 -1019
448 4212 1564 -323 570 7225 3092 -1026
121
449 4240 1576 -327 571 7248 3105 -1033
450 4267 1589 -331 572 7270 3118 -1041
451 4294 1601 -336 573 7293 3131 -1048
452 4321 1613 -340 574 7315 3144 -1055
453 4347 1625 -344 575 7338 3157 -1063
454 4374 1637 -349 576 7360 3170 -1070
455 4401 1650 -353 577 7383 3183 -1077
456 4428 1662 -357 578 7405 3196 -1085
457 4455 1674 -362 579 7428 3208 -1092
458 4481 1686 -366 580 7450 3221 -1100
459 4508 1698 -371 581 7472 3234 -1107
460 4535 1711 -375 582 7494 3247 -1114
461 4561 1723 -380 583 7517 3260 -1122
462 4588 1735 -384 584 7539 3273 -1129
463 4614 1747 -389 585 7561 3286 -1137
464 4641 1760 -394 586 7583 3299 -1145
465 4667 1772 -398 587 7605 3312 -1152
466 4693 1784 -403 588 7628 3325 -1160
467 4720 1796 -408 589 7650 3338 -1167
468 4746 1809 -412 590 7672 3351 -1175
469 4772 1821 -417 591 7694 3364 -1183
470 4798 1833 -422 592 7716 3377 -1191
471 4825 1846 -427 593 7738 3390 -1198
472 4851 1858 -432 594 7760 3403 -1206
473 4877 1870 -437 595 7782 3416 -1214
474 4903 1882 -441 596 7804 3429 -1222
475 4929 1895 -446 597 7825 3442 -1229
476 4955 1907 -451 598 7847 3455 -1237
477 4980 1919 -456 599 7869 3469 -1245
478 5006 1932 -461 600 7891 3482 -1253
479 5032 1944 -466 601 7913 3495 -1261
480 5058 1956 -471 602 7934 3508 -1269
481 5083 1969 -476 603 7956 3521 -1277
482 5109 1981 -481 604 7978 3534 -1285
483 5135 1994 -487 605 8000 3547 -1293
484 5160 2006 -492 606 8021 3560 -1301
485 5186 2018 -497 607 8043 3573 -1309
486 5211 2031 -502 608 8064 3586 -1317
487 5237 2043 -507 609 8086 3599 -1325
488 5262 2055 -513 610 8107 3613 -1333
122
489 5288 2068 -518 611 8129 3626 -1341
490 5313 2080 -523 612 8150 3639 -1349
491 5338 2093 -528 613 8172 3652 -1357
492 5364 2105 -534 614 8193 3665 -1366
493 5389 2117 -539 615 8215 3678 -1374
494 5414 2130 -545 616 8236 3692 -1382
495 5439 2142 -550 617 8258 3705 -1390
496 5464 2155 -555 618 8279 3718 -1398
497 5489 2167 -561 619 8300 3731 -1407
498 5514 2180 -566 620 8321 3744 -1415
499 5539 2192 -572 621 8343 3757 -1423
500 5564 2205 -578 622 8364 3771 -1432
501 5589 2217 -583 623 8385 3784 -1441
502 5614 2230 -589 62315 8388 3786 -1443
123
Appendix E
Table E1 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in solid state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 913 287 -014
299 025 007 000 331 941 296 -015
300 054 016 000 332 970 306 -016
301 083 025 000 333 998 315 -017
302 112 034 000 334 1026 324 -018
303 141 042 000 335 1054 334 -019
304 170 051 000 336 1081 343 -020
305 199 060 -001 337 1109 353 -021
306 228 069 -001 338 1137 362 -022
307 257 078 -001 339 1165 371 -024
308 286 087 -001 340 1193 381 -025
309 315 096 -002 341 1221 390 -026
310 343 105 -002 342 1248 400 -027
311 372 113 -002 343 1276 409 -028
312 401 122 -003 344 1304 419 -030
313 430 131 -003 345 1331 428 -031
314 458 140 -003 346 1359 438 -032
315 487 149 -004 347 1386 447 -034
316 516 159 -004 348 1414 457 -035
317 544 168 -005 349 1441 466 -036
318 573 177 -006 350 1468 476 -038
319 602 186 -006 351 1496 486 -039
320 630 195 -007 352 1523 495 -041
321 659 204 -007 353 1550 505 -042
322 687 213 -008 354 1577 514 -044
323 715 222 -009 355 1605 524 -046
324 744 232 -009 356 1632 534 -047
325 772 241 -010 357 1659 543 -049
326 800 250 -011 358 1686 553 -050
327 829 259 -012 359 1713 563 -052
328 857 269 -013 35915 1717 564 -052
329 885 278 -013
124
Table E2 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in liquid state (376-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2323 777 -094 500 5525 2173 -590
376 2347 786 -096 501 5548 2184 -595
377 2375 797 -098 502 5572 2196 -601
378 2403 808 -101 503 5595 2208 -606
379 2431 818 -103 504 5619 2220 -612
380 2459 829 -106 505 5642 2232 -618
381 2487 839 -108 506 5665 2243 -623
382 2515 850 -111 507 5689 2255 -629
383 2542 861 -113 508 5712 2267 -635
384 2570 871 -116 509 5735 2279 -640
385 2598 882 -118 510 5759 2291 -646
386 2626 893 -121 511 5782 2303 -652
387 2653 903 -123 512 5805 2315 -658
388 2681 914 -126 513 5828 2326 -664
389 2708 925 -129 514 5852 2338 -669
390 2736 935 -132 515 5875 2350 -675
391 2763 946 -134 516 5898 2362 -681
392 2791 957 -137 517 5921 2374 -687
393 2818 968 -140 518 5944 2386 -693
394 2845 978 -143 519 5967 2398 -699
395 2873 989 -146 520 5990 2410 -705
396 2900 1000 -148 521 6013 2422 -711
397 2927 1011 -151 522 6036 2434 -717
398 2954 1022 -154 523 6059 2446 -723
399 2981 1032 -157 524 6082 2458 -729
400 3008 1043 -160 525 6105 2470 -735
401 3035 1054 -163 526 6128 2482 -741
402 3062 1065 -166 527 6151 2494 -747
403 3089 1076 -169 528 6173 2506 -754
404 3116 1086 -172 529 6196 2518 -760
405 3143 1097 -176 530 6219 2530 -766
125
406 3170 1108 -179 531 6242 2542 -772
407 3197 1119 -182 532 6265 2554 -778
408 3223 1130 -185 533 6287 2566 -785
409 3250 1141 -188 534 6310 2578 -791
410 3277 1152 -192 535 6333 2591 -797
411 3303 1163 -195 536 6355 2603 -804
412 3330 1174 -198 537 6378 2615 -810
413 3356 1185 -202 538 6400 2627 -816
414 3383 1195 -205 539 6423 2639 -823
415 3409 1206 -208 540 6445 2651 -829
416 3436 1217 -212 541 6468 2663 -836
417 3462 1228 -215 542 6490 2676 -842
418 3488 1239 -219 543 6513 2688 -849
419 3515 1250 -222 544 6535 2700 -855
420 3541 1261 -226 545 6558 2712 -862
421 3567 1272 -229 546 6580 2724 -868
422 3593 1283 -233 547 6602 2737 -875
423 3619 1294 -236 548 6625 2749 -882
424 3645 1305 -240 549 6647 2761 -888
425 3671 1317 -244 550 6669 2773 -895
426 3697 1328 -247 551 6692 2786 -902
427 3723 1339 -251 552 6714 2798 -908
428 3749 1350 -255 553 6736 2810 -915
429 3775 1361 -259 554 6758 2822 -922
430 3801 1372 -262 555 6780 2835 -929
431 3827 1383 -266 556 6803 2847 -935
432 3852 1394 -270 557 6825 2859 -942
433 3878 1405 -274 558 6847 2872 -949
434 3904 1416 -278 559 6869 2884 -956
435 3929 1428 -282 560 6891 2896 -963
436 3955 1439 -286 561 6913 2909 -970
437 3981 1450 -290 562 6935 2921 -977
438 4006 1461 -294 563 6957 2933 -983
439 4032 1472 -298 564 6979 2946 -990
440 4057 1483 -302 565 7001 2958 -997
441 4083 1495 -306 566 7023 2971 -1004
442 4108 1506 -310 567 7045 2983 -1011
443 4133 1517 -314 568 7067 2995 -1019
444 4159 1528 -318 569 7089 3008 -1026
445 4184 1540 -322 570 7110 3020 -1033
126
446 4209 1551 -327 571 7132 3033 -1040
447 4234 1562 -331 572 7154 3045 -1047
448 4260 1573 -335 573 7176 3058 -1054
449 4285 1585 -339 574 7198 3070 -1061
450 4310 1596 -344 575 7219 3083 -1069
451 4335 1607 -348 576 7241 3095 -1076
452 4360 1618 -352 577 7263 3108 -1083
453 4385 1630 -357 578 7284 3120 -1090
454 4410 1641 -361 579 7306 3133 -1098
455 4435 1652 -365 580 7328 3145 -1105
456 4460 1664 -370 581 7349 3158 -1112
457 4485 1675 -374 582 7371 3170 -1120
458 4510 1687 -379 583 7393 3183 -1127
459 4534 1698 -383 584 7414 3195 -1134
460 4559 1709 -388 585 7436 3208 -1142
461 4584 1721 -393 586 7457 3221 -1149
462 4609 1732 -397 587 7479 3233 -1157
463 4633 1743 -402 588 7500 3246 -1164
464 4658 1755 -406 589 7522 3258 -1172
465 4683 1766 -411 590 7543 3271 -1179
466 4707 1778 -416 591 7564 3284 -1187
467 4732 1789 -420 592 7586 3296 -1194
468 4756 1801 -425 593 7607 3309 -1202
469 4781 1812 -430 594 7628 3322 -1210
470 4805 1824 -435 595 7650 3334 -1217
471 4830 1835 -440 596 7671 3347 -1225
472 4854 1847 -444 597 7692 3360 -1233
473 4878 1858 -449 598 7714 3373 -1240
474 4903 1870 -454 599 7735 3385 -1248
475 4927 1881 -459 600 7756 3398 -1256
476 4951 1893 -464 601 7777 3411 -1264
477 4975 1904 -469 602 7799 3423 -1271
478 5000 1916 -474 603 7820 3436 -1279
479 5024 1927 -479 604 7841 3449 -1287
480 5048 1939 -484 605 7862 3462 -1295
481 5072 1951 -489 606 7883 3475 -1303
482 5096 1962 -494 607 7904 3487 -1311
483 5120 1974 -499 608 7925 3500 -1318
484 5144 1985 -504 609 7946 3513 -1326
485 5168 1997 -510 610 7967 3526 -1334
127
486 5192 2009 -515 611 7988 3539 -1342
487 5216 2020 -520 612 8009 3551 -1350
488 5240 2032 -525 613 8030 3564 -1358
489 5264 2044 -530 614 8051 3577 -1366
490 5288 2055 -536 615 8072 3590 -1374
491 5312 2067 -541 616 8093 3603 -1383
492 5335 2079 -546 617 8114 3616 -1391
493 5359 2090 -552 618 8135 3629 -1399
494 5383 2102 -557 619 8156 3642 -1407
495 5407 2114 -562 620 8177 3655 -1415
496 5430 2126 -568 621 8198 3667 -1423
497 5454 2137 -573 622 8219 3680 -1431
498 5478 2149 -579 623 8239 3693 -1440
499 5501 2161 -584 62315 8242 3695 -1441
128
Appendix F
Table F1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in solid
state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 1063 334 -017
299 029 009 000 331 1096 345 -018
300 063 019 000 332 1128 356 -019
301 097 029 000 333 1161 366 -020
302 131 039 000 334 1193 377 -021
303 165 050 000 335 1225 388 -022
304 199 060 -001 336 1258 399 -024
305 233 070 -001 337 1290 410 -025
306 267 081 -001 338 1322 421 -026
307 300 091 -001 339 1355 432 -028
308 334 101 -002 340 1387 443 -029
309 368 112 -002 341 1419 454 -030
310 401 122 -002 342 1451 464 -032
311 435 133 -003 343 1483 475 -033
312 468 143 -003 344 1515 486 -035
313 502 153 -004 345 1547 497 -036
314 535 164 -004 346 1578 508 -038
315 569 174 -005 347 1610 519 -039
316 602 185 -005 348 1642 531 -041
317 635 196 -006 349 1674 542 -043
318 668 206 -006 350 1705 553 -044
319 702 217 -007 351 1737 564 -046
320 735 227 -008 352 1769 575 -048
321 768 238 -009 353 1800 586 -049
322 801 248 -009 354 1832 597 -051
323 834 259 -010 355 1863 608 -053
324 867 270 -011 356 1894 619 -055
325 900 280 -012 357 1926 631 -057
326 932 291 -013 358 1957 642 -059
327 965 302 -014 359 1988 653 -061
328 998 313 -015 35915 1993 655 -061
329 1030 323 -016
129
Table F2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in liquid
state (37515-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2691 926 -083 500 6111 2416 -640
376 2717 936 -085 501 6136 2428 -646
377 2747 948 -088 502 6161 2440 -652
378 2778 959 -091 503 6185 2453 -658
379 2808 971 -094 504 6210 2465 -665
380 2838 982 -096 505 6235 2478 -671
381 2869 994 -099 506 6259 2490 -677
382 2899 1005 -102 507 6284 2502 -683
383 2929 1017 -105 508 6308 2515 -690
384 2959 1028 -108 509 6333 2527 -696
385 2989 1040 -111 510 6357 2540 -702
386 3019 1051 -114 511 6381 2552 -709
387 3049 1063 -117 512 6406 2565 -715
388 3079 1075 -120 513 6430 2577 -721
389 3109 1086 -123 514 6454 2590 -728
390 3138 1098 -126 515 6479 2602 -734
391 3168 1109 -129 516 6503 2615 -741
392 3198 1121 -133 517 6527 2627 -747
393 3227 1132 -136 518 6551 2640 -754
394 3257 1144 -139 519 6575 2652 -760
395 3286 1156 -142 520 6599 2665 -767
396 3316 1167 -146 521 6624 2677 -774
397 3345 1179 -149 522 6648 2690 -780
398 3374 1191 -152 523 6672 2702 -787
399 3403 1202 -156 524 6696 2715 -794
400 3433 1214 -159 525 6719 2727 -800
401 3462 1226 -163 526 6743 2740 -807
402 3491 1237 -166 527 6767 2753 -814
403 3520 1249 -170 528 6791 2765 -821
404 3549 1261 -173 529 6815 2778 -827
405 3578 1272 -177 530 6839 2790 -834
130
406 3606 1284 -180 531 6862 2803 -841
407 3635 1296 -184 532 6886 2815 -848
408 3664 1307 -187 533 6910 2828 -855
409 3693 1319 -191 534 6933 2841 -862
410 3721 1331 -195 535 6957 2853 -869
411 3750 1343 -199 536 6981 2866 -876
412 3778 1354 -202 537 7004 2879 -883
413 3807 1366 -206 538 7028 2891 -890
414 3835 1378 -210 539 7051 2904 -897
415 3864 1390 -214 540 7075 2917 -904
416 3892 1401 -218 541 7098 2929 -911
417 3920 1413 -222 542 7122 2942 -918
418 3948 1425 -226 543 7145 2955 -925
419 3977 1437 -230 544 7168 2967 -932
420 4005 1449 -234 545 7192 2980 -939
421 4033 1460 -238 546 7215 2993 -947
422 4061 1472 -242 547 7238 3005 -954
423 4089 1484 -246 548 7261 3018 -961
424 4117 1496 -250 549 7285 3031 -968
425 4145 1508 -254 550 7308 3044 -976
426 4172 1519 -258 551 7331 3056 -983
427 4200 1531 -262 552 7354 3069 -990
428 4228 1543 -266 553 7377 3082 -998
429 4256 1555 -271 554 7400 3095 -1005
430 4283 1567 -275 555 7423 3107 -1013
431 4311 1579 -279 556 7446 3120 -1020
432 4338 1591 -284 557 7469 3133 -1027
433 4366 1603 -288 558 7492 3146 -1035
434 4393 1614 -292 559 7515 3159 -1042
435 4421 1626 -297 560 7538 3171 -1050
436 4448 1638 -301 561 7561 3184 -1058
437 4475 1650 -306 562 7584 3197 -1065
438 4503 1662 -310 563 7607 3210 -1073
439 4530 1674 -315 564 7629 3223 -1080
440 4557 1686 -319 565 7652 3235 -1088
441 4584 1698 -324 566 7675 3248 -1096
442 4611 1710 -328 567 7697 3261 -1103
443 4638 1722 -333 568 7720 3274 -1111
444 4665 1734 -338 569 7743 3287 -1119
445 4692 1746 -342 570 7765 3300 -1126
131
446 4719 1758 -347 571 7788 3313 -1134
447 4746 1770 -352 572 7811 3326 -1142
448 4773 1782 -356 573 7833 3338 -1150
449 4800 1794 -361 574 7856 3351 -1158
450 4826 1806 -366 575 7878 3364 -1166
451 4853 1818 -371 576 7901 3377 -1173
452 4880 1830 -376 577 7923 3390 -1181
453 4906 1842 -381 578 7945 3403 -1189
454 4933 1854 -386 579 7968 3416 -1197
455 4959 1866 -391 580 7990 3429 -1205
456 4986 1878 -396 581 8012 3442 -1213
457 5012 1890 -401 582 8035 3455 -1221
458 5039 1902 -406 583 8057 3468 -1229
459 5065 1914 -411 584 8079 3481 -1237
460 5091 1926 -416 585 8101 3494 -1245
461 5118 1938 -421 586 8124 3507 -1254
462 5144 1951 -426 587 8146 3520 -1262
463 5170 1963 -431 588 8168 3533 -1270
464 5196 1975 -436 589 8190 3546 -1278
465 5222 1987 -441 590 8212 3559 -1286
466 5248 1999 -447 591 8234 3572 -1294
467 5274 2011 -452 592 8256 3585 -1303
468 5300 2023 -457 593 8278 3598 -1311
469 5326 2035 -463 594 8300 3611 -1319
470 5352 2048 -468 595 8322 3624 -1328
471 5378 2060 -473 596 8344 3637 -1336
472 5404 2072 -479 597 8366 3650 -1344
473 5430 2084 -484 598 8388 3663 -1353
474 5455 2096 -490 599 8410 3676 -1361
475 5481 2108 -495 600 8432 3690 -1369
476 5507 2121 -500 601 8454 3703 -1378
477 5532 2133 -506 602 8475 3716 -1386
478 5558 2145 -512 603 8497 3729 -1395
479 5583 2157 -517 604 8519 3742 -1403
480 5609 2170 -523 605 8541 3755 -1412
481 5634 2182 -528 606 8562 3768 -1420
482 5660 2194 -534 607 8584 3781 -1429
483 5685 2206 -540 608 8606 3795 -1438
484 5710 2219 -545 609 8627 3808 -1446
485 5736 2231 -551 610 8649 3821 -1455
132
486 5761 2243 -557 611 8670 3834 -1464
487 5786 2255 -563 612 8692 3847 -1472
488 5812 2268 -568 613 8713 3860 -1481
489 5837 2280 -574 614 8735 3874 -1490
490 5862 2292 -580 615 8756 3887 -1498
491 5887 2305 -586 616 8778 3900 -1507
492 5912 2317 -592 617 8799 3913 -1516
493 5937 2329 -598 618 8821 3926 -1525
494 5962 2342 -604 619 8842 3940 -1534
495 5987 2354 -610 620 8864 3953 -1542
496 6012 2366 -616 621 8885 3966 -1551
497 6037 2379 -622 622 8906 3979 -1560
498 6062 2391 -628 623 8928 3993 -1569
499 6086 2403 -634 62315 8931 3995 -1570
133
Appendix G
Table G1 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid I state (29815-33715K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 319 578 162 -004
299 024 000 000 320 606 170 -005
300 052 000 000 321 633 179 -005
301 080 007 000 322 660 188 -006
302 108 016 000 323 688 197 -007
303 136 024 000 324 715 205 -007
304 164 032 000 325 742 214 -008
305 192 041 000 326 769 223 -009
306 219 049 000 327 796 232 -009
307 247 058 000 328 823 241 -010
308 275 067 -001 329 851 250 -011
309 303 075 -001 330 878 259 -011
310 330 084 -001 331 905 268 -012
311 358 092 -001 332 932 277 -013
312 386 101 -002 333 959 285 -014
313 413 109 -002 334 985 294 -015
314 441 118 -002 335 1012 303 -016
315 468 127 -003 336 1039 312 -017
316 496 135 -003 337 1066 321 -018
317 523 144 -003 33715 1070 331 -019
318 551 153 -004
Table G2 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid II state (36115-36415K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36115 2433 825 -054
134
362 2454 832 -056
363 2478 841 -059
364 2503 850 -061
36415 2506 851 -062
Table G3 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
liquid state (41115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
41115 3833 1366 -210 518 6604 2649 -772
412 3857 1376 -213 519 6628 2661 -778
413 3885 1387 -217 520 6652 2674 -785
414 3913 1399 -221 521 6675 2686 -792
415 3941 1411 -225 522 6699 2699 -798
416 3969 1422 -229 523 6723 2711 -805
417 3997 1434 -233 524 6747 2723 -812
418 4025 1446 -237 525 6770 2736 -819
419 4053 1457 -241 526 6794 2748 -825
420 4081 1469 -245 527 6818 2761 -832
421 4109 1481 -249 528 6841 2773 -839
422 4137 1493 -253 529 6865 2786 -846
423 4165 1504 -257 530 6888 2798 -853
424 4192 1516 -262 531 6912 2810 -860
425 4220 1528 -266 532 6935 2823 -867
426 4248 1539 -270 533 6959 2835 -873
427 4275 1551 -274 534 6982 2848 -880
428 4303 1563 -279 535 7005 2860 -887
429 4330 1575 -283 536 7029 2873 -894
430 4358 1587 -287 537 7052 2885 -902
431 4385 1598 -292 538 7075 2898 -909
432 4412 1610 -296 539 7098 2910 -916
433 4439 1622 -300 540 7122 2923 -923
434 4467 1634 -305 541 7145 2935 -930
135
435 4494 1646 -309 542 7168 2948 -937
436 4521 1657 -314 543 7191 2960 -944
437 4548 1669 -318 544 7214 2973 -951
438 4575 1681 -323 545 7237 2986 -959
439 4602 1693 -328 546 7260 2998 -966
440 4629 1705 -332 547 7283 3011 -973
441 4656 1716 -337 548 7306 3023 -980
442 4683 1728 -341 549 7329 3036 -988
443 4710 1740 -346 550 7352 3048 -995
444 4736 1752 -351 551 7375 3061 -1003
445 4763 1764 -356 552 7398 3074 -1010
446 4790 1776 -360 553 7420 3086 -1017
447 4816 1788 -365 554 7443 3099 -1025
448 4843 1800 -370 555 7466 3111 -1032
449 4869 1812 -375 556 7489 3124 -1040
450 4896 1823 -380 557 7511 3137 -1047
451 4922 1835 -385 558 7534 3149 -1055
452 4949 1847 -390 559 7557 3162 -1062
453 4975 1859 -395 560 7579 3175 -1070
454 5002 1871 -400 561 7602 3187 -1077
455 5028 1883 -405 562 7625 3200 -1085
456 5054 1895 -410 563 7647 3213 -1093
457 5080 1907 -415 564 7670 3225 -1100
458 5106 1919 -420 565 7692 3238 -1108
459 5132 1931 -425 566 7714 3251 -1116
460 5159 1943 -430 567 7737 3263 -1123
461 5185 1955 -435 568 7759 3276 -1131
462 5211 1967 -440 569 7782 3289 -1139
463 5236 1979 -446 570 7804 3302 -1147
464 5262 1991 -451 571 7826 3314 -1155
465 5288 2003 -456 572 7849 3327 -1162
466 5314 2015 -461 573 7871 3340 -1170
467 5340 2027 -467 574 7893 3352 -1178
468 5366 2039 -472 575 7915 3365 -1186
469 5391 2051 -478 576 7937 3378 -1194
470 5417 2063 -483 577 7960 3391 -1202
471 5442 2075 -488 578 7982 3404 -1210
472 5468 2087 -494 579 8004 3416 -1218
473 5494 2099 -499 580 8026 3429 -1226
474 5519 2111 -505 581 8048 3442 -1234
136
475 5545 2123 -510 582 8070 3455 -1242
476 5570 2135 -516 583 8092 3468 -1250
477 5595 2147 -521 584 8114 3480 -1258
478 5621 2160 -527 585 8136 3493 -1266
479 5646 2172 -533 586 8158 3506 -1274
480 5671 2184 -538 587 8180 3519 -1283
481 5696 2196 -544 588 8201 3532 -1291
482 5722 2208 -550 589 8223 3545 -1299
483 5747 2220 -555 590 8245 3557 -1307
484 5772 2232 -561 591 8267 3570 -1315
485 5797 2244 -567 592 8289 3583 -1324
486 5822 2257 -573 593 8310 3596 -1332
487 5847 2269 -579 594 8332 3609 -1340
488 5872 2281 -585 595 8354 3622 -1349
489 5897 2293 -590 596 8375 3635 -1357
490 5922 2305 -596 597 8397 3648 -1365
491 5947 2317 -602 598 8419 3660 -1374
492 5971 2330 -608 599 8440 3673 -1382
493 5996 2342 -614 600 8462 3686 -1391
494 6021 2354 -620 601 8483 3699 -1399
495 6046 2366 -626 602 8505 3712 -1408
496 6070 2379 -632 603 8526 3725 -1416
497 6095 2391 -638 604 8548 3738 -1425
498 6119 2403 -645 605 8569 3751 -1433
499 6144 2415 -651 606 8591 3764 -1442
500 6169 2427 -657 607 8612 3777 -1451
501 6193 2440 -663 608 8633 3790 -1459
502 6217 2452 -669 609 8655 3803 -1468
503 6242 2464 -675 610 8676 3816 -1476
504 6266 2477 -682 611 8697 3829 -1485
505 6291 2489 -688 612 8719 3842 -1494
506 6315 2501 -694 613 8740 3855 -1503
507 6339 2513 -701 614 8761 3868 -1511
508 6363 2526 -707 615 8782 3881 -1520
509 6388 2538 -713 616 8803 3894 -1529
510 6412 2550 -720 617 8825 3907 -1538
511 6436 2563 -726 618 8846 3920 -1547
512 6460 2575 -733 619 8867 3933 -1555
513 6484 2587 -739 620 8888 3946 -1564
514 6508 2600 -746 621 8909 3959 -1573
137
515 6532 2612 -752 622 8930 3972 -1582
516 6556 2624 -759 623 8951 3985 -1591
517 6580 2637 -765 62315 8954 3987 -1592
138
Appendix H
Table H1 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid I
state (29815-35415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 768 241 -011
299 023 007 000 328 794 249 -011
300 050 015 000 329 820 258 -012
301 077 023 000 330 846 266 -013
302 104 031 000 331 872 275 -014
303 131 039 000 332 898 284 -015
304 158 048 000 333 924 292 -016
305 185 056 -001 334 950 301 -016
306 212 064 -001 335 976 310 -017
307 239 072 -001 336 1002 318 -018
308 265 081 -001 337 1028 327 -019
309 292 089 -001 338 1053 336 -020
310 319 097 -002 339 1079 344 -021
311 345 105 -002 340 1105 353 -022
312 372 114 -002 341 1130 362 -024
313 399 122 -003 342 1156 371 -025
314 425 130 -003 343 1182 379 -026
315 452 139 -004 344 1207 388 -027
316 478 147 -004 345 1233 397 -028
317 505 156 -004 346 1258 406 -029
318 531 164 -005 347 1284 415 -031
319 558 172 -005 348 1309 424 -032
320 584 181 -006 349 1335 433 -033
321 611 189 -007 350 1360 441 -035
322 637 198 -007 351 1385 450 -036
323 663 206 -008 352 1411 459 -037
324 689 215 -008 353 1436 468 -039
325 716 223 -009 354 1461 477 -040
326 742 232 -010 35415 1465 478 -040
139
Table H2 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid 2
state (36215-37315K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36215 2387 777 -046
363 2408 809 -055
364 2432 817 -057
365 2457 826 -060
366 2481 835 -062
367 2506 843 -065
368 2530 852 -067
369 2555 861 -070
370 2579 870 -072
371 2604 879 -075
372 2628 888 -077
373 2653 898 -080
37315 2657 907 -083
Table H3 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in liquid
state (37915-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37915 2966 1025 -100 502 6174 2432 -667
380 2991 1034 -102 503 6198 2444 -674
381 3020 1045 -105 504 6222 2456 -680
382 3048 1056 -108 505 6246 2468 -686
383 3077 1067 -112 506 6270 2480 -692
384 3105 1078 -115 507 6294 2492 -699
385 3134 1089 -118 508 6317 2504 -705
386 3162 1100 -121 509 6341 2516 -711
387 3191 1111 -124 510 6365 2528 -718
140
388 3219 1122 -127 511 6388 2541 -724
389 3247 1133 -130 512 6412 2553 -730
390 3275 1144 -134 513 6436 2565 -737
391 3304 1155 -137 514 6459 2577 -743
392 3332 1166 -140 515 6483 2589 -750
393 3360 1177 -144 516 6506 2601 -756
394 3388 1188 -147 517 6530 2613 -763
395 3416 1199 -150 518 6553 2625 -769
396 3444 1210 -154 519 6577 2638 -776
397 3472 1221 -157 520 6600 2650 -782
398 3500 1232 -161 521 6624 2662 -789
399 3527 1243 -164 522 6647 2674 -796
400 3555 1254 -168 523 6670 2686 -802
401 3583 1265 -171 524 6694 2698 -809
402 3611 1276 -175 525 6717 2711 -816
403 3638 1287 -179 526 6740 2723 -822
404 3666 1299 -182 527 6763 2735 -829
405 3693 1310 -186 528 6786 2747 -836
406 3721 1321 -190 529 6810 2760 -843
407 3748 1332 -193 530 6833 2772 -850
408 3776 1343 -197 531 6856 2784 -856
409 3803 1354 -201 532 6879 2796 -863
410 3830 1366 -205 533 6902 2809 -870
411 3857 1377 -209 534 6925 2821 -877
412 3885 1388 -213 535 6948 2833 -884
413 3912 1399 -216 536 6971 2845 -891
414 3939 1410 -220 537 6994 2858 -898
415 3966 1422 -224 538 7017 2870 -905
416 3993 1433 -228 539 7040 2882 -912
417 4020 1444 -232 540 7063 2895 -919
418 4047 1455 -236 541 7086 2907 -926
419 4074 1467 -240 542 7108 2919 -933
420 4101 1478 -245 543 7131 2932 -940
421 4128 1489 -249 544 7154 2944 -947
422 4154 1500 -253 545 7177 2957 -955
423 4181 1512 -257 546 7199 2969 -962
424 4208 1523 -261 547 7222 2981 -969
425 4234 1534 -265 548 7245 2994 -976
426 4261 1546 -270 549 7267 3006 -984
427 4288 1557 -274 550 7290 3019 -991
141
428 4314 1568 -278 551 7313 3031 -998
429 4341 1580 -282 552 7335 3044 -1005
430 4367 1591 -287 553 7358 3056 -1013
431 4393 1602 -291 554 7380 3068 -1020
432 4420 1614 -296 555 7403 3081 -1028
433 4446 1625 -300 556 7425 3093 -1035
434 4472 1636 -305 557 7448 3106 -1042
435 4499 1648 -309 558 7470 3118 -1050
436 4525 1659 -314 559 7492 3131 -1057
437 4551 1671 -318 560 7515 3143 -1065
438 4577 1682 -323 561 7537 3156 -1072
439 4603 1694 -327 562 7560 3169 -1080
440 4629 1705 -332 563 7582 3181 -1087
441 4655 1716 -336 564 7604 3194 -1095
442 4681 1728 -341 565 7626 3206 -1103
443 4707 1739 -346 566 7649 3219 -1110
444 4733 1751 -351 567 7671 3231 -1118
445 4759 1762 -355 568 7693 3244 -1126
446 4785 1774 -360 569 7715 3257 -1133
447 4810 1785 -365 570 7737 3269 -1141
448 4836 1797 -370 571 7759 3282 -1149
449 4862 1808 -375 572 7782 3294 -1157
450 4888 1820 -379 573 7804 3307 -1164
451 4913 1832 -384 574 7826 3320 -1172
452 4939 1843 -389 575 7848 3332 -1180
453 4964 1855 -394 576 7870 3345 -1188
454 4990 1866 -399 577 7892 3358 -1196
455 5015 1878 -404 578 7914 3370 -1204
456 5041 1889 -409 579 7936 3383 -1212
457 5066 1901 -414 580 7957 3396 -1220
458 5092 1913 -419 581 7979 3408 -1228
459 5117 1924 -424 582 8001 3421 -1236
460 5142 1936 -430 583 8023 3434 -1244
461 5167 1947 -435 584 8045 3447 -1252
462 5193 1959 -440 585 8067 3459 -1260
463 5218 1971 -445 586 8088 3472 -1268
464 5243 1982 -450 587 8110 3485 -1276
465 5268 1994 -456 588 8132 3498 -1284
466 5293 2006 -461 589 8154 3510 -1292
467 5318 2017 -466 590 8175 3523 -1300
142
468 5343 2029 -472 591 8197 3536 -1308
469 5368 2041 -477 592 8219 3549 -1317
470 5393 2053 -482 593 8240 3562 -1325
471 5418 2064 -488 594 8262 3574 -1333
472 5443 2076 -493 595 8283 3587 -1341
473 5468 2088 -499 596 8305 3600 -1350
474 5493 2100 -504 597 8327 3613 -1358
475 5517 2111 -510 598 8348 3626 -1366
476 5542 2123 -515 599 8370 3639 -1375
477 5567 2135 -521 600 8391 3652 -1383
478 5592 2147 -526 601 8413 3664 -1391
479 5616 2158 -532 602 8434 3677 -1400
480 5641 2170 -537 603 8455 3690 -1408
481 5665 2182 -543 604 8477 3703 -1417
482 5690 2194 -549 605 8498 3716 -1425
483 5715 2206 -554 606 8520 3729 -1434
484 5739 2218 -560 607 8541 3742 -1442
485 5763 2229 -566 608 8562 3755 -1451
486 5788 2241 -572 609 8583 3768 -1459
487 5812 2253 -578 610 8605 3781 -1468
488 5837 2265 -583 611 8626 3794 -1477
489 5861 2277 -589 612 8647 3807 -1485
490 5885 2289 -595 613 8668 3820 -1494
491 5910 2301 -601 614 8690 3833 -1503
492 5934 2313 -607 615 8711 3846 -1511
493 5958 2324 -613 616 8732 3859 -1520
494 5982 2336 -619 617 8753 3872 -1529
495 6006 2348 -625 618 8774 3885 -1538
496 6030 2360 -631 619 8795 3898 -1546
497 6055 2372 -637 620 8816 3911 -1555
498 6079 2384 -643 621 8837 3924 -1564
499 6103 2396 -649 622 8858 3937 -1573
500 6127 2408 -655 623 8879 3950 -1582
501 6151 2420 -661 62315 8883 3952 -1583
143
Appendix I
Table I1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in solid state (29815-35315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 1171 366 -017
299 035 010 000 328 1211 379 -018
300 076 023 000 329 1250 392 -019
301 117 035 000 330 1290 405 -021
302 158 048 000 331 1330 418 -022
303 199 060 000 332 1369 431 -023
304 240 072 -001 333 1409 444 -025
305 281 085 -001 334 1448 458 -026
306 322 097 -001 335 1488 471 -028
307 363 110 -002 336 1527 484 -029
308 404 122 -002 337 1566 497 -031
309 445 135 -002 338 1605 510 -032
310 486 148 -003 339 1644 524 -034
311 526 160 -003 340 1683 537 -036
312 567 173 -004 341 1722 550 -037
313 608 186 -005 342 1761 563 -039
314 648 198 -005 343 1800 577 -041
315 689 211 -006 344 1839 590 -043
316 729 224 -007 345 1877 603 -044
317 770 237 -007 346 1916 617 -046
318 810 250 -008 347 1955 630 -048
319 850 262 -009 348 1993 643 -050
320 891 275 -010 349 2031 657 -052
321 931 288 -011 350 2070 670 -054
322 971 301 -012 351 2108 683 -056
323 1011 314 -013 352 2146 697 -059
324 1051 327 -014 353 2184 710 -061
325 1091 340 -015 35315 2190 712 -061
326 1131 353 -016
144
Table I2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in liquid state (39115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
39115 4413 1056 -191 508 8890 3521 -978
392 4450 1535 -195 509 8924 3538 -986
393 4492 1549 -200 510 8959 3556 -995
394 4535 1566 -204 511 8993 3574 -1004
395 4577 1583 -209 512 9027 3591 -1013
396 4620 1599 -213 513 9062 3609 -1022
397 4662 1616 -218 514 9096 3626 -1031
398 4704 1633 -223 515 9130 3644 -1041
399 4746 1650 -227 516 9164 3661 -1050
400 4789 1666 -232 517 9198 3679 -1059
401 4831 1683 -237 518 9232 3697 -1068
402 4872 1700 -242 519 9266 3714 -1077
403 4914 1717 -247 520 9300 3732 -1087
404 4956 1734 -252 521 9334 3750 -1096
405 4997 1751 -257 522 9368 3767 -1105
406 5039 1767 -262 523 9402 3785 -1115
407 5080 1784 -267 524 9435 3802 -1124
408 5122 1801 -272 525 9469 3820 -1134
409 5163 1818 -277 526 9503 3838 -1143
410 5204 1835 -282 527 9536 3855 -1152
411 5245 1852 -287 528 9570 3873 -1162
412 5286 1869 -293 529 9603 3891 -1172
413 5327 1885 -298 530 9637 3908 -1181
414 5368 1902 -303 531 9670 3926 -1191
415 5409 1919 -309 532 9703 3944 -1201
416 5450 1936 -314 533 9737 3962 -1210
417 5490 1953 -320 534 9770 3979 -1220
418 5531 1970 -325 535 9803 3997 -1230
419 5571 1987 -331 536 9836 4015 -1240
420 5612 2004 -336 537 9869 4032 -1249
421 5652 2021 -342 538 9902 4050 -1259
145
422 5692 2038 -347 539 9935 4068 -1269
423 5732 2055 -353 540 9968 4086 -1279
424 5772 2072 -359 541 10001 4104 -1289
425 5812 2089 -365 542 10034 4121 -1299
426 5852 2106 -371 543 10066 4139 -1309
427 5892 2123 -376 544 10099 4157 -1319
428 5932 2140 -382 545 10132 4175 -1329
429 5971 2157 -388 546 10165 4192 -1340
430 6011 2174 -394 547 10197 4210 -1350
431 6051 2191 -400 548 10230 4228 -1360
432 6090 2208 -406 549 10262 4246 -1370
433 6129 2225 -412 550 10295 4264 -1380
434 6169 2242 -419 551 10327 4282 -1391
435 6208 2259 -425 552 10359 4299 -1401
436 6247 2276 -431 553 10392 4317 -1411
437 6286 2293 -437 554 10424 4335 -1422
438 6325 2310 -444 555 10456 4353 -1432
439 6364 2327 -450 556 10488 4371 -1443
440 6403 2344 -456 557 10520 4389 -1453
441 6442 2361 -463 558 10553 4407 -1464
442 6480 2378 -469 559 10585 4424 -1474
443 6519 2395 -476 560 10617 4442 -1485
444 6557 2412 -482 561 10648 4460 -1496
445 6596 2429 -489 562 10680 4478 -1506
446 6634 2446 -495 563 10712 4496 -1517
447 6673 2464 -502 564 10744 4514 -1528
448 6711 2481 -509 565 10776 4532 -1538
449 6749 2498 -515 566 10808 4550 -1549
450 6787 2515 -522 567 10839 4568 -1560
451 6825 2532 -529 568 10871 4586 -1571
452 6863 2549 -536 569 10902 4604 -1582
453 6901 2566 -543 570 10934 4622 -1593
454 6939 2584 -550 571 10965 4640 -1604
455 6977 2601 -557 572 10997 4658 -1615
456 7015 2618 -564 573 11028 4676 -1626
457 7052 2635 -571 574 11060 4694 -1637
458 7090 2652 -578 575 11091 4712 -1648
459 7128 2670 -585 576 11122 4730 -1659
460 7165 2687 -592 577 11154 4748 -1670
461 7202 2704 -599 578 11185 4766 -1681
146
462 7240 2721 -606 579 11216 4784 -1692
463 7277 2738 -614 580 11247 4802 -1704
464 7314 2756 -621 581 11278 4820 -1715
465 7351 2773 -628 582 11309 4838 -1726
466 7388 2790 -636 583 11340 4856 -1737
467 7425 2807 -643 584 11371 4874 -1749
468 7462 2825 -650 585 11402 4892 -1760
469 7499 2842 -658 586 11433 4910 -1772
470 7536 2859 -665 587 11464 4928 -1783
471 7573 2877 -673 588 11495 4946 -1794
472 7609 2894 -680 589 11525 4964 -1806
473 7646 2911 -688 590 11556 4982 -1817
474 7682 2928 -696 591 11587 5001 -1829
475 7719 2946 -703 592 11617 5019 -1841
476 7755 2963 -711 593 11648 5037 -1852
477 7792 2980 -719 594 11678 5055 -1864
478 7828 2998 -727 595 11709 5073 -1876
479 7864 3015 -735 596 11739 5091 -1887
480 7900 3032 -742 597 11770 5109 -1899
481 7937 3050 -750 598 11800 5128 -1911
482 7973 3067 -758 599 11831 5146 -1923
483 8009 3084 -766 600 11861 5164 -1935
484 8045 3102 -774 601 11891 5182 -1946
485 8080 3119 -782 602 11921 5200 -1958
486 8116 3137 -791 603 11952 5218 -1970
487 8152 3154 -799 604 11982 5237 -1982
488 8188 3171 -807 605 12012 5255 -1994
489 8223 3189 -815 606 12042 5273 -2006
490 8259 3206 -823 607 12072 5291 -2018
491 8294 3224 -832 608 12102 5309 -2030
492 8330 3241 -840 609 12132 5328 -2042
493 8365 3259 -848 610 12162 5346 -2055
494 8401 3276 -857 611 12192 5364 -2067
495 8436 3293 -865 612 12222 5382 -2079
496 8471 3311 -873 613 12252 5401 -2091
497 8506 3328 -882 614 12281 5419 -2103
498 8542 3346 -890 615 12311 5437 -2116
499 8577 3363 -899 616 12341 5456 -2128
500 8612 3381 -908 617 12370 5474 -2140
501 8647 3398 -916 618 12400 5492 -2153
147
502 8681 3416 -925 619 12430 5510 -2165
503 8716 3433 -934 620 12459 5529 -2178
504 8751 3451 -942 621 12489 5547 -2190
505 8786 3468 -951 622 12518 5565 -2203
506 8820 3486 -960 623 12548 5584 -2215
507 8855 3503 -969 62315 12552 5602 -2217
vii
631 Density calibration 86
632 Results and discussions 82
64 Thermal energy storage density of molten salts 90
CHAPTER 7 CONCLUSION 94
REFERENCES 96
APPENDIX 104
APPENDIX A 104
APPENDIX B 109
APPENDIX C 114
APPENDIX D 118
APPENDIX E 123
APPENDIX F 128
APPENDIX G 133
APPENDIX H 138
APPENDIX I 143
viii
LIST OF TABLES
21 Melting point of various nitrate salt systems 12
22 Melting point of various carbonate salt systems 13
23 Melting point of various fluoridechloride salt systems 14
24 Melting point of various hydroixde salt systems 15
25 Density coefficients A and B of nitrate salts 16
26 Density coefficients A and B of carbonate salts 17
27 Density coefficients A and B of chloridefluoride salts 17
28 Density coefficients A and B of molten salt mixture with hydroxide salts 18
29 Heat capacity of alkali nitrate salt at 500oC 19
210 Heat capacity of alkali carbonate salt at 500oC 19
211 Heat capacity of fluoridechloride salt at 500oC 20
212 Heat capacity of hydroxide salt at 500oC 21
41 Calculated composition and melting point for multi-component systems 29
61 Calibration data of melting points with different samples 35
62 DSC results of melting point transition point and change of enthalpy 41
ix
63 Fusion and solid phase transition temperature for individual salts 42
64 Melting points of candidate systems as function of temperatures 51
65 Calibration data of heat capacities with different samples 52
66 Heat capacity of selected new TES molten salt mixtures 54
67 Change of Gibbs energy values at 62315K for molten salt systems 85
68 Calibration of density measurements with different pure nitrate salts 86
69 Coefficient of A and B for density determination of salt 1 to salt 9 87
610 Extrapolated value of density and heat capacity at 500oC of salt 1 to salt 9 91
611 Energy density of salt 1 to salt 9 compare to solar salt 92
612 Gravimetric storage densities for solar salt and new molten salts 93
x
LIST OF FIGURES
11 Theoretical and engineering energy conversion efficiency as function of temperature 6
12 Gravimetric storage density for different energy storage systems
as function of temperature 8
51 Photography of set-up for DSC equipment 31
61 Melting point calibration with indium sample 34
62 Melting point calibration with KNO3 sample 35
63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt 36
64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt 37
65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt 37
66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt 38
67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt 38
68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt 39
69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt 39
610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt 40
611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN Salt 40
612 DSC plot of 698wt KNO3 -302wt NaNO2 binary system 43
xi
613 DSC plot of 270wt NaNO3-730wt KNO3 binary system 45
614 DSC plot of 458wtLiNO3-542wtKNO3 binary system 45
615 DSC plot of 460wt NaNO3-540wt KNO3 binary system 46
616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 20oCmin heating rate 47
616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 5oCmin heating rate 48
617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 5oCmin heating rate 49
617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 20oCmin heating rate 49
618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system
as function of temperature 53
619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K 54
620 Change of Gibbs energy as function of temperature for molten salt systems 85
621 The densities of the salt 1 to salt 5 as function of temperature 87
622 The densities of the salt 6 to salt 9 as function of temperature 89
623 Densities of the salt 1 salt 2 as function of temperature compared to
the equimolar NaNO3-KNO3 binary system and pure KNO3 90
624 Gravimetric storage density comparison of different energy storage
xii
systems as function of temperature 93
1
CHAPTER 1
INTRODUCTION
Renewable energy sources such as wind solar water power geothermal and biomass are
playing more and more significant role in our energy supply Because the cheap cost and infinite
amount of energy storage inside the resource solar energy is emphasized since 20th
century and
viewed as promising alternative method to satisfy the large energy consumption every day in the
world reduce the emission of carbon and strengthen the economy
The wind energy was used as a clean energy to generate electricity back to late 19th
century
However this renewable energy source was not emphasized due to the cheap price of fossil fuel
The re-emergence happened in mid 1950s when the amount of traditional energy source was
found apparently decrease The development of wind energy usage continued and in 1990 the
first mega-watt wind turbine was launched which was viewed as a symbol of shift to large scale
wind energy utilization [1-2] The modern application of wind energy mainly relies on wind
turbine On the basis of aerodynamic wind turbine generates certain net positive torque on
rotating shaft and then converts the mechanical power to electrical power As an electrical power
generator wind turbine is connected to some electrical network to transport the electricity to
battery charging utilities residential power systems and large scale energy consuming systems
In general most of wind turbines are small scale and can only generate 10KW electrical power
Only few of the wind turbine systems operate with capacity as large as 5MW Although the
usage of wind energy can reduce the emission of carbon oxide the noise pollution and high cost
2
limit its large scale application Since the wind is not transportable the electrical energy can only
be generated where the wind blows which also decrease the flexibility of wind energy
Water power is another term of alternative power supply and it was used for irrigation
operating machines like watermill even before the development of electrical power The modern
application of water power is to generate electricity by using the gravitational force of falling or
flowing water These days there are various ways for the water power application The most
traditional method is to store the water in dam and generate electricity by converting the
potential energy pump storage is a different way to utilize water power and can change its
output depending on the energy demand by moving water between reservoirs at different
elevations In the low energy demand period excess energy is used to lift water to the higher
level while in the peak period of energy demand the water is released back to the lower
elevation through water turbine Water power can also be converted by taking advantage of
naturally raise and fall of tide to satisfy the demand of electrical energy consumption [3]
Although the usage of water power can reduce the emission of carbon dioxide and cost it will
destroy the ecosystem because of the large land required for construction There will be methane
emission from the reservoir the potential failure hazard of dam is also a fatal issue and flow
shortage caused by drought may also create serious problem As result of that water power
technique is not a long-term alternative choice
Geothermal energy is the energy form generated inside the earth At the very beginning of
the planet formation a large amount of thermal energy was stored from the radioactive decay of
minerals volcanic activity and solar energy absorption Because of the temperature difference
3
between the core and the surface of planet the thermal energy stored inside the earth is driven to
the outer surface in the form of heat This form of renewable energy source can be applied to
generate electrical power and heat for industrial space and agricultural applications
Theoretically the deposited amount of geothermal energy is adequate to supply the energy
consumption in the world However most of the geothermal energy is stored deeply near the
core of the earth the deep drilling and exploration of geothermal energy is very expensive and
limits the large-scale use of this renewable energy source [4]
Biomass is a renewable energy source used to generate heat or electricity with living or
recently living organism such as wood waste (hydrogen) gas and alcohol fuels The biomass
energy can be converted to electrical energy by thermal method such as combustion pyrolysis
and gasification Several specific chemical processes may also be able to convert the biomass
energy to other forms The main problem arise from application of biomass is air pollution which
contains carbon monoxide NOx (nitrogen oxides) VOCs (volatile organic compounds)
particulates and other pollutants And the level of air pollution to some extent is even above that
of traditional fuel resource Some other possible issue like transportation and sink of carbon also
limit the wide usage of this type of alternative energy [5]
Among all the renewable energy sources solar energy is the most suitable alternative
energy for our future life It is clean cheap abundant without any noise air pollution no
transportation issue and easy to be obtained anywhere in the earth Inside the core of the Sun
hydrogen fuses into helium with a rate of 7times1011
kgs and generates very powerful nucleation
power This type of nucleation explosion creates ultra high temperature in the core of the Sun
4
which reaches approximately 16 million K degrees Although the Sun is not perfectly black body
it still radiates abundant power with the energy density as 16times107 wattsm
2 [6-7] Because of the
enough amount of hydrogen underneath the surface of the Sun the radiation given arise of from
the nucleation explosion can continue at least 5 million years with the same rate and strength
The energy reaching the earth is vastly reduced mainly caused by the absorption and spreading
of the radiation It is easily to understand that there are numerous amorphous objects all around
the entire universe which can absorb certain portion of the radiation for the Sun Moreover the
light generated from the spherical object such as the Sun fills all the available space between the
origin to the destination Even though the energy will not be lost in the travelling process due to
the long distance between the Sun to the earth the surface area of the sphere which is formed
with the Sun as center and the distance as radius is much larger than that of the earth As the
result of that only 1340Wm2 finally reaches the upmost surface of the earth Even though the
final amount of the received solar energy is very small compared to that is initially radiated from
the Sun the average daily solar radiation falling on one area in the continental United States is
equivalent in total energy content to 11 barrels of oil In summary the solar energy itself is
relatively unlimited useful clean and almost unexploited energy and definitely can behave as
the promising mean for the future energy supply [8]
There are several different methods to take advantage of the solar energy and all the
methods can be distinguished into three group solar parabolic trough solar tower and solar dish
Parabolic trough is constructed by silver coated parabolic mirror and there is a Dewar tube going
through the length of the mirror and set on the focal point all the radiation is concentrated on the
tube and transfer by heat transfer fluid to the thermal energy storage unit Solar tower are used to
5
capture solar energy with thousands of mirrors and focus the concentrated sunlight to the top of
the tower which is located in the middle of the heliostats The thermal energy storage medium
within the tower was heated to high temperature and transferred to thermal energy storage tank
and eventually sent to steam pump The solar dish is built with a large reflective parabolic dish
which concentrates all the received sunlight to one spot There is normally a receiver located on
the focal point and transform the solar energy to other forms of useful energy The working
upper limit temperature of solar parabolic trough system is the lowest among these three systems
normally its maximum working temperature is within the range from 400-500oC the solar tower
has higher maximum working temperature which ranges from 500-1000oC the solar dish has the
highest working upper limit temperature which reaches 700-1200oC [9]
The energy conversion efficiency is the most concerned parameter in the solar energy
storage application and the theoretical and real engineering efficiency are given in fig 11 as
function of temperature The theoretical conversion efficiency can be up to 80 while in real
application the value is always less than 70 regardless of collectors The actual efficiency
increases with temperature in the whole working temperature As a result of that the thermal
energy storage materials in solar parabolic trough for instance should be able to work stably at
the upper limit temperature of this type of collection system which is 500oC to ensure the highest
efficiency [9 10]
6
Fig 11 Theoretical and engineering energy conversion efficiency as function of
temperature
Solar energy can be stored in three major forms sensible heat latent heat and
thermochemical heat Sensible heat storage was utilized based on the heat capacity and the
change as function of temperature of storage materials in the charging and discharging process
which correspond to the absorbing and withdrawing energy processes respectively The sensible
heat stored from the melting point to the maximum working temperature can be expressed by
equation 1 [9]
[1]
Where m is the mass of storage material Tmp and TH are melting point temperature and high
temperature in the same phase respectively Cp(T) is the heat capacity at different temperature
Because the sensible heat storage materials remain in a single phase in the working temperature
range the charging and discharging processes are completely reversible for unlimited cycles
7
Latent heat storage is operated by absorbing and withdrawing energy in the charging and
discharging processes accompanied with fusion of materials [9] The latent heat collected
throughout the working temperature range can be expressed by equation 2 as following
[2]
Where T is temperature in solid state Tmp is melting point temperature of storage material TH is
the high temperature in liquid state and is enthalpy of fusion
Thermochemical heat storage is based on the heat capacity and its change as function of
temperature accompanied with chemical reaction The thermochemical heat collected throughout
the working temperature range can be expressed by equation 3
[3]
Where TL is the low temperature before the reaction TR is the reaction temperature and
is the enthalpy of chemical reaction Because of the destruction of the chemical bonds
in the reaction process the charging and discharging process cannot be completely reversible
which reduces the stability and recyclability of storage operation [10]
Sensible energy storage method is chosen to ensure the efficient usage of solar energy for
parabolic trough system of which the maximum working temperature ranges from 400-500oC
Different from thermochemical heat storage the sensible heat storage can achieve completely
reversible working condition under unlimited cycles Also fig 12 illustrates that the sensible
heat storage materials mainly work in the working temperature range for parabolic trough system
8
and the gravimetric energy storage densities of sensible heat is higher than that of latent heat
materials [9 -11]
Fig 12 Gravimetric storage density for different energy storage systems as function of
temperature
Various materials are chosen to serve as thermal energy storage fluid for sensible heat
such as water thermal oil ionic liquid and molten salt [12] The properties of different heat
transfer fluid determine the performance of solar energy heating system In these days the
efficiency and cost of output of electrical power mainly relies on the parabolic trough solar
power plant and the thermal storage fluid [12] A large investment cost is needed to dispatch
100MW to 200MW energy by consuming the energy transfer fluids Given by this situation the
development of new thermal storage fluid with higher thermal energy storage density is
paramount to lower the expense for generating energy and a lot of effect has been put on design
of new systems [13-16]
9
Water is commonly used as heat transfer and thermal energy storage fluid in industry
because of its low cost high heat capacity and high thermal conductivity However the
limitation for using this medium is also obvious that the temperature range within which the
liquid state can be assured is too small It is well know that water can only serve as thermal
energy storage liquid above the freezing point 0oC and below the boiling temperature 100
oC In
practical experiment the actual temperature range is even less than 100oC because of the large
amount of weight loss near the boiling temperature due to the high vapor pressure Water is
possible to work above 100oC only if high pressure is also applied to avoid the phase
transformation but the cost will be highly increased Accordingly water is only suitable to work
in low temperature below 100oC
Thermal oils are also being used in the parabolic trough solar power plant and have very
low melting point as low as 12oC [17 18] However the application of the oil for the thermal
energy storage liquid is limited by some disadvantages from the physic-chemical properties The
upper limit for this oil is only 300oC and above that the liquid state cannot be maintained
Moreover the low thermal decomposition temperature low density and low heat capacity result
in limited thermal energy storage capacity Since the working temperature range is so narrow the
rankie cycle efficiency is reduced when using the synthetic oil and the cost for generating power
is considered to be very expensive [19 20]
Ionic liquid is another medium served as thermal energy storage fluid The liquid
temperature range of ionic liquid is large which is one of the main advantages of this type of
material The high heat capacity and density ensure the efficiency of thermal energy storage of
10
ionic liquid What‟s more the excellent chemical stability and little vapor pressure increase the
lifetime [21-24] However as a result of the very serve corrosion problem to the liquid container
and the high cost the usage of ionic liquid is still limited
Considering various relative physic-chemical properties of thermal energy storage system
molten salts have been proposed as a suitable group for a wide temperature range application
They are being emphasized in the solar energy applications because of their low melting point
and high upper limit which can increase the stable working range The high heat capacity
increases the thermal energy storage density of the heat storage system excellent thermal
stability and negligible vapor pressure ensure the steadiness of cyclic repeating in the lifetime
[25] low viscosity strengths the mobility and efficiency of the thermal storage liquid low
utilization cost reduce the investment and protect the economy The liquidus temperature range
of the molten salt varies from 150-600oC combination of various salts can bring the melting
down and further increase the working temperature range Due to these properties molten salts
can be excellent thermal energy storage fluid in the solar power generation system
11
CHAPTER 2
LITERATURE REVIEW
Several physical and thermodynamic properties of thermal energy storage fluid play
significant role in determining the efficiency and performance of solar energy storage systems In
order to evaluate the feasibility of systems the physic-chemical properties of several molten salts
should be reviewed The three determining parameter which directly affect the thermal energy
storage capacity in systems are melting point heat capacity and density
There are large amount of melting point data available in the literature for various molten
salt system in previous literatures while those with melting point less than 120oC is very limited
All the previous study on molten salt system revealed that five group of molten salts are
emphasized and commonly used alkai or alkaline nitrates carbonates sulphates chloride and
hydroxides Although most of the systems have the same group of cation the melting point
varies a lot from one to anther due to the different effect of anions
21 Melting point
The melting points of individual and multi-component nitratenitrite systems are listed in
Table 21[26-31] Among those systems solar salt (NaNO3KNO3 6040) is the thermal energy
storage medium which is currently being used with the freezing point of 221oC [27] Although
the melting point for this system is highest in all the candidate mixtures in this group the lowest
12
combined compound cost makes it widely used in solar energy storage field Another ternary
system HITEC which contains NaNO3 KNO3 and NaNO2 has freezing point of 141 oC [28]
This combination brings the melting point down but the lack of combination of optimum features
limits its further application [29] Some mixtures such as LiNO3-Ca(NO3)2-KNO3 are not often
utilized because they increase the compound cost at the same time of lowering the melting point
to around 120oC [30] moreover the decreased melting point is still high compared to the
organic oil There are also several systems have the melting points less than 100oC or even 60
oC
they are not used in the parabolic trough solar power plant due to the decomposition of some
components during high temperature [31]
Table 21 Melting point of various nitrate salt systems
Compound Melting Point (ordmC)
LiNO3 253
NaNO3 307
KNO3 334
Ca(NO3)2 561
Sr(NO3)2 570
Ba(NO3)2 590
NaNO3-NaNO2 221
NaNO3-NaNO2-KNO3 141
NaNO3-KNO3-CaNO3 133
LiNO3-KNO3-NaNO3 120
KNO3-CaNO3-LiNO3 117
LiNO3-KNO3-NHNO3 92
KNO3-NHNO3-AgNO3 52
The melting points of individual and multi-component carbonate systems are listed in
Table 22 [26 32 33] Different from the nitrate salts the melting points for both the individual
13
and multi-component carbonate systems are on the higher side The lowest melting point is
achieved with lithium sodium and potassium carbonate ternary system whose melting point is
still 277oC higher than that of the nitrate ternary system with the same cations [32] Besides
because of the thermal decomposition issue the choice of component involved in the multi-
component carbonate systems is limited Some salt like CaCO3 doesn‟t have stable form at high
temperature and the lack of multi-component system reduces the chance of the synthesis of low
melting point salt mixtures Even though this group of salt is not thermally stable and the
working temperature range is relatively small it is still viewed as possible candidate working at
high temperature due to its low price
Table 22 Melting point of various carbonate salt systems
Compound Melting Point (ordmC)
Li2CO3 732
Na2CO3 858
K2CO3 900
MgCO3 990
Na2CO3-K2CO3 710
Li2CO3-Na2CO3 496
Li2CO3-K2CO3 488
Li2CO3-K2CO3-Na2CO3 397
Alkali and Alkaline fluoridechloride salts are also selected as one possible choice as the
thermal energy storage fluid and the melting point examined from previous literatures are given
in table 23 [34-38] A lot of study has been done for this group of salt and the melting points
were found in the same range as the carbonate group And for the pure salt metal chloride salts
have lower melting point than metal fluoride ones
14
Table 23 Melting point of various fluoridechloride salt systems
Compound Melting Point (ordmC)
LiF 849
NaF 996
KF 858
LiCl 610
NaCl 801
KCl 771
LiF-KF 493
LiF-NaF 652
LiCl-KF 487
LiF-NaF-KF 454
LiF-NaF-KF-MgF2 449
LiF-KF-BaF2 320
LiF-KF-CsF-RbF 256
Several studies were also conducted to determine the melting point of molten hydroxide
salts and the results are shown in Table24 The data of pure salts and multi-component mixtures
merely in this group were not much determined in the literatures Generally they are mixed with
other groups of anion and form some low melting point salt mixtures [39-42] On the basis of the
previous literature data alkali hydroxide salts and their mixture with salts in other groups have
relatively lower melting point compared with pure carbonate and fluoride chloride group salt
mixtures Most of the melting points given in Table 4 are lower than 300oC sodium potassium
hydroxide binary mixture even reaches the melting point below 200oC Accordingly relatively
large temperature range can be obtained by using hydroxide salt mixtures or adding them as
additive
15
Table 24 Melting point of various hydroixde salt systems
Compound Melting Point (ordmC)
LiOH-LiF 427
NaOH-KOH 170
LiOH-NaOH 213
NaOH-NaNO2 232
NaOH-NaNO3 237
NaOH-NaCl-NaNO3 242
NaOH-NaCl-Na2CO3 282
22 Density
For the solar energy storage system density for the thermal energy storage fluid is also
essential parameter The density is needed for the size calculation as function of temperature and
assessing for the thermal stability of thermoclines Besides density as function of temperature is
used to evaluate the volume change in the process of freezing which contributes to potential
stress
Alkalialkaline nitrate salts were studied very much about their density as function of
temperature All the results indicate that the density was decreased linearly as temperature
increases and any specific density value in the molten state can be expressed by equation as
equation 4
= A-BT [4]
Where (gcm3) is the density of salt A (gcm
3) is the initial density value at 0
oC and B
(mgcm3degC) is the density change slope as function of temperature The coefficients are shown in
16
Table 25 for the nitrate group molten salts Among these systems pure sodium nitrate has the
largest value which reveals the high initial density value at low temperature [43] Conversely
lithium nitrate has the lowest value while it presents the smallest decrease trend as temperature
increases [44] The densities and A B values of multi-component nitrate salts were included in
the range of those two salts discussed above
Table 25 Density coefficients A and B of nitrate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiNO3 1922 0556
NaNO3 2334 0767
KNO3 2127 0760
NaNO3-KNO3 2134 0773
KNO3-CaNO3-LiNO3 2172 0735
LiNO3-KNO3-NaNO3 2083 0715
Several experiments were also conducted to measure the density as function of temperature
for the individual and multi-component carbonate salt systems The density of the carbonate salt
also follow the same trend as that of nitrate salt and the temperature dependence of density
followed the linear equation as discussed above It is observed that all the carbonate salts have
higher initial density coefficient A than the nitrate salt The largest value is reached to 2511 and
even the lowest value in this group is greater than the maximum A of nitrate group [45-49]
What‟s more the regression slope coefficient B of carbonate salt is lower compared to that of the
nitrate salt group Accordingly the salts in this group present larger density in the molten state
and the density coefficient A and B are given in Table 26
17
Table 26 Density coefficients A and B of carbonate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
Li2CO3 2303 0532
Na2CO3 2350 0448
Na2CO3-K2CO3 2473 0483
Li2CO3-K2CO3 2511 0599
Li2CO3-Na2CO3 2456 0519
Li2CO3-Na2CO3-K2CO3 2364 0544
Density of metal fluoride and chloride molten salt were also examined and present similar
regression trend as temperature increases The linear temperature dependence is also expressed
by the same equation On the basis of previous literature data the pure chloride salt shows lower
density than the fluoride salt with the same cation in the molten state [49] What‟s more the
sodium halide salt has the largest density value while the lithium halide salt has the lowest value
which is very similar to the nitrate group salt The density determination coefficient A and B are
given in Table27
Table 27 Density coefficients A and B of chloridefluoride salts
Compound A(gcm3) Btimes103(gcm
3degC)
LiCl 1766 0432
NaCl 1991 0543
KCl 1976 0583
LiF 2226 0490
NaF 2581 0636
KF 2469 0651
LiF-NaF 2520 0818
LiCl-NaF-KCl 2436 0742
LiF-NaF-MgF 2240 0701
18
The density measurement of hydroxide was not conducted as much as those three anion
groups discussed above Only few data of density is available for the alkali hydroxide salt when
added into other salt systems and temperature dependence also follows the linear regression
trend [32 41] The density determination coefficient A and B are given in Table 28
Table 28 Density coefficients A and B of molten salt mixture with hydroxide salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiCl-LiOH 16 0443
LiF-LiOH 165 0471
23 Heat capacity
In the heating process the temperature of solar energy storage molten salt is increase by
absorbing energy from the solar radiation Conversely the same amount of heat is released and
applied to heating system in the process of cooling Heat capacity is the amount of heat required
to increase the temperature of certain material by 1 oC and can be viewed as the directly relevant
parameter to the energy storage ability To some extent the large heat capacity assures the
efficiency of the application of solar energy storage materials
The heat capacity of alkalialkaline nitrate salt was investigated for both individual and
multi-component system in the previous literature To simplify the comparison only the heat
capacity value at 500oC is shown in all the following tables In the liquid state the heat capacity
increases with temperature following linear equation and the increasing slope is as small as 10-5
to 10-4
[50 51] Among those alkali nitrate salt systems lithium nitrate has the largest heat
19
capacity at 500oC while potassium nitrate presents the lowest value at that temperature In table
29 the heat capacity results at the selected temperature in literature are given
Table 29 Heat capacity of alkali nitrate salt at 500oC
Compound Heat capacity(JgK)
LiNO3 2175
NaNO3 1686
KNO3 1400
NaNO3-KNO3 1533
LiNO3-KNO3 1642
LiNO3-KNO3-NaNO3 1681
For the carbonate salt systems in the molten state the heat capacity is almost constant and
almost independent with temperature [32 33] Same as the nitrate group salts the heat capacity
for pure carbonate salt decreases as the atomic number of the alkali element increases which
means the value for lithium carbonate is the largest and that of potassium carbonate is the
smallest Generally the heat capacity value for carbonate in molten state is larger than that in
solid state However the sodium-potassium carbonate binary system is an exception for which
the heat capacity in solid state is larger than liquid state In table 210 the heat capacity results of
carbonate salts at the selected temperature in literature are given
Table 210 Heat capacity of alkali carbonate salt at 500oC
Compound Heat Capacity(JgK)
Li2CO3 250
Na2CO3 178
K2CO3 151
Na2CO3-K2CO3 157
20
Li2CO3-K2CO3 160
Li2CO3-Na2CO3 209
Li2CO3-K2CO3-Na2CO3 163
The heat capacity of fluoridechloride salt was measured in several literature and found
that for the pure salt the lithium halide has the biggest heat capacity data in the molten state
while the potassium halides shows the lowest heat capacity value Similar to the carbonate group
the heat capacity value of fluoridechloride salt varies little with temperature in the liquid state
[32 33] The values at 500oC for the alkalialkaline halides are shown in Table 211
Table 211 Heat capacity of fluoridechloride salt at 500oC
Compound Heat Capacity (JgK)
LiCl 148
NaCl 115
KCl 090
LiF-KF 163
NaCl-MgCl2 100
LiF-NaF-KF 155
KCl-MgCl2-CaCl2 092
The heat capacity of pure and multi-component hydroxide salt systems is limited in the
previous literature and the values in the liquid state follow linear equation which is observed for
all the molten salt discussed above [52] The values at 500oC for the alkalialkaline halides are
shown in Table 212
21
Table 212 Heat capacity of hydroxide salt at 500oC
Compound Heat Capacity(JgK)
NaOH 188
LiOH-NaOH 221
NaOH-KOH 182
In summary on the basis of comparison of various physic-chemical properties molten
nitrate slats have relatively low melting point excellent working temperature range reasonable
density and high heat capacity As the result of that molten nitrate salt is suitable to be applied as
the thermal energy storage fluid in the solar energy storage system
22
CHAPTER 3
OBJECTIVES
Based on review of previous literature data it is found that there are several disadvantages
such as the high melting point relatively low density value or poor heat capacity in liquid state
which limit the application of molten salt in certain groups in solar thermal energy storage
system Conversely alkalialkaline nitrate salt is considered as the suitable choice and proposed
as the thermal energy storage liquid for high temperature
Currently the used thermal energy storage liquid is NaNO3 (60mol)-KNO3 (40mol)
binary system (solar salt) which has the melting point at 221oC [30] Although the melting point
for this salt mixture is not the lowest it is still emphasized because of its low investment cost
However there are some drawbacks for this binary nitrate mixture The main disadvantage is
the high melting point In evenings or in winter the molten salt can easily freeze and block the
pipeline As a result of that some auxiliary cost should be added to overcome this problem and
the total investment will be increased
Development and synthesis of newer molten salt mixtures with freezing point lower than
those currently used for thermal energy storage applications is necessary for higher efficiency of
utilization of solar energy and getting rid of any unnecessary cost The approach to develop
lower freezing point molten salt mixtures is by the prediction of new eutectic mixtures and also
23
by the development of new nitrate compounds Besides these two most well known systems
several other mixtures were also studied Preliminary evaluation of several new molten salt flux
systems based on requirements for thermal energy storage systems mainly including freezing
point density heat capacity viscosity and thermal energy storage density The promising
candidate low melting point molten salt system should satisfy the requirements that eutectic
melting temperatures are lower than 220oC and the thermal energy storage densities are higher
than binary solar salt It is known that the melting point can be lowered by the addition of one or
more ABNO3 nitrate compounds where A and B are cations Consequently several multi-
component systems which have more constituent salts than solar salt were came up with and
studied with little fundamental data on the physic-chemical properties at the required operating
conditions available at present
In this thesis the new systems with simulated eutectic compositions were tested for their
experimental melting points heat capacities using the Differential Scanning Calorimetry (DSC)
technique which is considered to be the accurate instrument for thermodynamic data analysis
[53-59] Some significant thermodynamic properties such as heat capacity enthalpy and entropy
and Gibbs energy were calculated in the thesis to evaluate the energy change of the system in the
phase change process and the potential of being applied in the parabolic trough solar power plant
The energy density was obtained by using the experimental measured density and heat capacity
of the mixtures in molten state Finally 9 down-selected systems were present and discussed
24
CHAPTER 4
THERMODYNAMIC MODELING OF SALT SYSTEMS
41 Thermodynamic modeling
To lower the melting point of solar energy storage system multi-component system is
applicable Thermodynamic model was introduced to predict the eutectic temperature of salt
systems based on the Gibbs energies of fusion of individual salt and that of mixing of constituent
binary systems At the eutectic temperature the Gibbs energies in the liquid state and solid state
of salt are equal In thermodynamics Gibbs energy of fusion can be expressed by the equation
given as follows
G = H-TS [5]
Where H is the change of enthalpy of fusion and S is the change of entropy of fusion Equally
the entropy change of fusion can be expressed by differentiating G and the equation is given
[6]
It is known that the change in entropy can be expressed in terms of change in heat capacity in the
melting process as
[7]
25
If the change of heat capacity is assume to be independent of temperature the integral of
from Tm to T can be shown as
[8]
where Sm is the entropy of fusion at the melting point which is equal to Accordingly
Eq8 can be rewritten as
[9]
Substituting Eq 9 in Eq 6 and integrating the equation from Tm to T we get
[10]
Eq 10 illustrates that by using the change of heat capacity melting point and enthalpy of fusion
the Gibbs energy change at any temperature can be obtained
The standard Gibbs energy of fusion of a salt bdquo1‟ can be expressed in terms of the activity
of the salt as
[11]
where is the molar excess Gibbs energy and X1 is the molefraction of the salt bdquo1‟ Gibbs
energy of fusion at any give temperature T is expressed by Eq 7 in terms of its molefraction and
partial molar excess Gibbs energy
26
Take LiNO3-NaNO3-KNO3 as an example in which the integral molar excess Gibbs energy is
composed of the summation of the Gibbs energies of three constituent binary system and one
ternary The expression of the integral excess Gibbs energy is given by Eq12
[12]
Gibbs energies of the three constituent binary systems LiNO3-NaNO3 LiNO3-KNO3 and
NaNO3-KNO3 of the LiNO3-NaNO3-KNO3 ternary system are taken from the literature [48 49]
The Gibbs energies of mixing or the integral excess Gibbs energies of the three constituent
binary systems of the LiNO3-NaNO3-KNO3 ternary system are given below
LiNO3-NaNO3 Binary System
Jmol [13]
LiNO3-KNO3 Binary System
Jmol [14]
NaNO3-KNO3 Binary System
Jmol [15]
When assume the intergral excess Gibbs energy of to be zero the excess Gibbs energy in
the ternary system can be expressed by the summation of three constituent binary systems
[16]
27
Generally the partial molar excess Gibbs energies are reduced from the integral molar
excess Gibbs energy and can be expressed by the generalized equation for certain ldquomrdquo
component salt as
[17]
In the ternary system the i value equals to 12 and 3 and the partial molar excess Gibbs energy
of mixing for each component can be expressed as follows
[18]
[19]
[20]
Based on Eq 7 and the partial molar excess Gibbs energy of individual component the
Gibbs energy in the fusion can be expressed as Eq21- 23
[21]
[22]
[23]
42 Calculations
The fusion of the ternary salt system is defined by solutions of Eq 21-Eq 23 Newton-
Raphson method can be used to solve these three non-linear equations by linearizing the non-
linear equations using the Taylor series and truncating the series to first order derivatives
28
Consider the three non-linear functions F G and H in three variables x y and z The three
equations that are solved for the three variables are written as
F(x y z) = 0
G(x y z) = 0
H(x y z) = 0 [24]
The partial derivatives of the function F with respect to x y and z are given as
[25]
Similarly the partials derivatives can be expressed for the other two functions G and H
Newton-Raphson iterative method of solving the three equations in three variables
essentially deals with the solution of the incremental vector in the matrix equation given below
[26]
For the initial values of x y and z (say xi yi and zi) the right hand side vector contains the
values of the functions at the initial values (xi yi and zi) The 3times3 matrix on the left hand side
contains the partial derivatives of the functions with respect to the three variables at the initial
values Solutions of the matrix equation (Eq 26) result in the increments of the variables x y
and z The variables for the next iteration will then be xi + x yi + y and zi + z The
process of solving the matrix equation (Eq 26) is continued until the increments in the variables
x y and z is less than a very small quantity The iteration process is then said to be
29
converged and the values of the variables at convergence of the solution are the roots of the
system of the three fusion equations
The composition of LiNO3 NaNO3 and KNO3 and the eutectic temperature is solved by
using the Newton-Raphson iterative method Different from the data in previous literature the
eutectic temperature for the ternary is 116oC Besides the composition for each component is
also different from those published in literatures The new molten ternary system is composed of
2592 wt LiNO3 2001 wt NaNO3 and 5407 wt KNO3 The similar method is also applied
to other multi-component systems to determine the composition and eutectic temperature The
predicted melting points for new solar energy storage system are given Table41
Table 41 Calculated composition and melting point of multi-component molten salts systems
System Composition (wt) Calc Tmp
LiNO3 NaNO3 KNO3 NaNO2 KNO2 Mg(NO3)2 MgKN (degC)
Salt 1 259 20 541 - - - - 116
Salt 2 - 161 547 292 - - - 1238
Salt 3 175 142 505 178 - - - 986
Salt 4 115 104 274 - - - 507 986
Salt 5 172 139 476 172 41 - - 957
Salt 6 9 423 336 - 151 - - 1000
Salt 7 193 - 546 237 24 - - 1081
Salt 8 193 - 559 239 - 09 - 1008
Salt 9 154 172 324 - - 83 267 1036
30
CHAPTER 5
EXPERIMENTAL PROCEDURE
51 Melting point determination of molten salt mixtures
511 Materials
Ternary quaternary and quinary nirate and nitrite mixtures were tested in the thesis Most
components in the mixtures don‟t require any pre-preparation and can be used as received The
only exception is new developed MgKN which was composed of 6667 mol KNO3 and 3333
mol Mg(NO3)2 This unique compound is synthesized from magnesium nitrate hexahydrate
(98 Alfa Aesar) and potassium nitrate (ACS 990 min Alfa Aesar) and added into the
mixture as one single component As received magnesium nitrate hexahydrate is dehydrated
before synthesizing MgKN compound Weighted amount of magnesium nitrate taken in a
stainless steel crucible and placed on a hot plate in an argon atmosphere Temperature of the salt
is measured with a thermocouple immersed in the salt The temperature was held at 52315 K for
2 hours The salt solidifies to a white mass The temperature of the salt is then raised to 57315 K
slowly to remove any traces of moisture and to ensure complete dehydration The complete
removal of water is ascertained by weight loss
512 Apparatus and Procedure
31
Differential scanning calorimetry (DSC) analysis was performed using Perkin Elmer
Diamond DSC instrument and the setup is shown in fig 51 Heat flow and temperature can be
recorded in the instrument with an accuracy of 00001 mW and 001 K respectively The
measurements were made under purified nitrogen atmosphere with a flow rate of 20ccmin and at
a heating rate of 5 Kmin
Fig 51 Photography of set-up for DSC equipment
After dehydration if necessary each component was weighed to an accuracy of 01mg with
the electrical balance and mixed thoroughly in a stainless steel crucible Later the mixture is
heated up to certain temperature at which the entire salt melts At this temperature the salt
mixture was held for about 30 minutes The salt mixture is allowed to air cool to ambient
temperature This procedure is repeated 3 to 4 times to get the well-mixed compound Standard
aluminum pan with lid used for DSC measurements are weighed before the experiment Small
amount of the synthesized compound is placed carefully in the aluminum pan and closed with
the lid The lid is crimped by a sample press and the pan is weighed The weight of the sample is
32
determined by removing the weight of the pan and lid For the determination of melting point
and heat capacity (20-25) mg of the sample was used
Perkin-Elmer Diamond Differential Scanning Calorimeter (DSC) is used to measure the
melting point and heat capacity of compound The crimped ample pan was immediately put
inside the sample chamber of DSC after preparation and held at 52315 K for 10 hours to remove
the trace amount of moisture possibly caught in the process of loading sample and also to ensure
a homogeneous mixture In the experimental procedure a temperature range from 29815 K to
52315 K was set with a heating rate of 5 K min
1 followed by a cooling cycle at the same rate
This cycle is repeated for at least 6 times to ensure good mixture of the sample and
reproducibility of the results
52 Heat Capacity determination of molten salt mixtures
To start Cp measurement the same procedure as that of melting point determination is
followed with an addition of bdquoiso-scan-iso‟ steps to the program after 5-cycle temperature scan
Starting from 29815 K the temperature was held for 5 minutes before and after each scan step
Small temperature scan range is chosen to avoid thermal resistance between device and testing
sample except when the temperature is approaching the melting temperature The upper limit for
the Cp measurement was set to 62315 K in our experiments Since the change in the molar heat
capacity of the salt in the liquid state is very small the Cp data in the liquid state can be easily fit
to an equation and extrapolated to higher temperatures To get the value of molar heat capacity
of the sample heat flow curve for the baseline of the empty sample pan also needs to be obtained
immediately following the identical ldquoiso-scan-isordquo steps which were used for the actual sample
33
run The difference of heat flow between the actual crimpled sample and the empty sample pan is
the absolute heat absorbed by the test sample
53 Density determination of molten salt mixtures
Density measurement was carried out with standard densitometer which has fixed volume
Initial weight of the densitometer is measured and noted Salt composition of which the density
is measured is placed in a beaker on a hot place The densitometer is also placed on the same hot
plate The temperature is set to a fixed value above the melting point of the salt and is measured
by a thermocouple After the salt is melted and when the temperature shows stable reading the
molten salt is poured in to the densitometer up to the set mark on the sensitometer bottle The
weight of the densitometer with the molten salt is measured The weight difference between this
weight and the weight of empty densitometer gives the weight of the molten salt at the fixed set
temperature By knowing the fixed volume in the densitometer the density of the salt at that
temperature can be calculated This procedure is repeated at least three times to accurately
determine the density of the salt
34
CHAPTER 6
RESULT AND DISCUSSION
61 Melting point determination
611 DSC equipment calibration
Before the actual melting point measurement pure indium zinc metal and several
individual salts were used to calibrate the DSC equipment For metals only one sharp peak was
observed for each and the heat flow curve for indium metal is shown in fig 61 However larger
and boarder peaks are found for salts just like the condition illustrated in fig 62 for pure
potassium nitrate Based on the results shown in Table 61 the experimental data for melting
points and enthalpies of fusion have excellent agreement with the literature values [60-63] The
variation of point is within 07 and the variation of change of enthalpy is less than 3
Figure 61 Melting point calibration with indium sample
35
Figure 62 Melting point calibration with KNO3 sample
Table 61 Calibration data of melting points with different samples
Sample
Lit
Tmp
Expt
Tmp
Lit
Ttrans
Expt
Ttrans
Lit
ΔHfusion
Expt
ΔHfusion
Lit
ΔHtrans
Expt
ΔHtrans
degC degC degC degC Jg Jg Jg Jg
Indium 1566 1563 - - 286 278 - -
Zinc 4195 4188 - - 1086 1068 - -
LiNO3 2567 2550 - - 3617 3633 - -
NaNO3 3100 3081 2770 2753 1777 1756 147 152
KNO3 3370 3372 1330 1332 993 1005 538 529
612 Results
Differential scanning calorimetry (DSC) was used to determine the melting point and any
solid state phase transitions of the salt mixture A low scanning rate was chosen to record the
heat flow curve as function of temperature in order to improve the sensitivity of detection [64] It
helps to pick up any small endothermic peaks and also avoids the thermal resistance between the
36
internal furnace and sample Nine systems were chosen to test and the eutectic composition is
already listed in Table 41
All the selected systems are composed of alkaline nitrate and nitrite and most of them have
three basic components which are lithium sodium potassium nitrate or nitrite All the quaternary
and quinary systems were developed on the basis of the LiNO3-NaNO3-KNO3 baseline ternary
Figure 63-611 shows the DSC plot of all the salt systems DSC plots for each system were
collected for at least five runs (each run with fresh salt preparation) to ensure the reproducibility
All the onset temperatures peak temperatures predicted temperatures enthalpy of fusion for
melting peaks and the solid phase transformation temperatures are given in Table62
Figure 63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt
37
Figure 64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt
Figure 65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt
38
Figure 66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt
Figure 67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt
39
Figure 68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
Figure 69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
40
Figure 610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt
Figure 611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN salt
Table 62 illustrates that the predicted melting point is close to the experimental
determined value and most deviation is within 10 except for system 9 The great agreement
41
between experimental and calculated data verifies the accuracy and feasibility of the
thermodynamic modeling
Table 62 DSC results of melting point transition point and predicted melting point
System Tmp Ttrans ΔHfusion
Calculated degC Onset degC Peak degC Peak degC Jg
Salt 1 1160 994 1191 1043 600
Salt 2 1238 1150 1240 NA 97
Salt 3 986 940 999 NA 244
Salt 4 986 940 1010 NA 60
Salt 5 957 910 950 NA 62
Salt 6 1000 930 960 NA 86
Salt 7 1081 992 1003 793 60
Salt 8 1008 1010 1019 853 59
Salt 9 1036 834 892 NA 93
613 Discussion
It is observed that the first curve is different from last ones shown in the DSC plots and
this phenomenon is common for all the melting point measurement with DSC technique This
happened because in the first cycle the moisture caught by salt mixture especially the lithium
nitrate was removed in the process of heating Moreover the partially solidified sample in the
sample loading process can be re-homogenized in the first heating cycle [65-67] In figure 63
69 and 610 more than one endothermic peak was found The first smaller endothermic peak
refers to solid state phase transition of the salt mixture The second larger endothermic peak
refers to the melting of the salt Normally the onset temperature of transition is taken as the
experimental transition point for any metallic sample However in case of molten salts mixtures
since the thermal conductivity is low [68-74] the complete transition is ensured only at the peak
42
transition temperature The thermal gradient which exists due to the low thermal conductivity of
the salt results in internal heat flow which enhances the mixing in the salt Thus the transition
temperature is defined as the peak temperature of phase transition For salt No1 the small
endothermic peak happened before and was connected to the main peak which occurred at
39027K The first endothermic peaks for salt No 7 and 8 occurred at almost the same
temperature because of the similar composition for these two compounds Since the small
amount of magnesium nitrate and potassium nitrite contained in these two compounds the small
endothermic peak can hardly be related to these two components Obviously the rest three major
components must have something to do with the first peaks happened before the melting peaks
for both cases Each component among the major three ones were tested to find out any possible
solid phase transition peaks of them and the results shown in Table 63 which reveals that
lithium nitrate doesnt have any phase transition peak in solid state while potassium nitrate and
sodium nitrite both own the solid phase transformation peaks before their melting peaks
Table 63 Fusion and solid phase transition temperature for individual salts
System Tmp degC Ttrans degC ΔHfusion Jg ΔHtrans Jg
LiNO3 2550 - 3633 -
KNO3 3372 1332 1005 529
NaNO2 4311 4170 1119 880
The further investigation was carried out by running the KNO3-NaNO2 (550 wt and 238 wt )
binary compound with the very similar weight percentage as that in salt No 7 (546 wt and
237 wt) and salt No 8 (559wt and 239wt) By converting the weight percentage of the
studied binary system into 100 scale the weight fraction for sodium nitrate and potassium
nitrate can be rewritten as 698wt and 302wt The DSC plot for this binary system was
43
shown in fig 612 Although the solid transition and melting temperature were brought down by
adding lithium nitrate the shape of the plots in fig 69 and 610 are identical to that shown in fig
612 The enthalpy of solid state transformation of the binary salt was also converted to that in
both quaternary systems by using the weight fraction occupied by the binary system and the
comparable change of converted enthalpy between the binary system and two quaternary systems
indicates the relevance of the solid transition peaks in salt 7 and 8 to the combined effect of
potassium nitrate and sodium nitrite
Figure 612 DSC plot of 698wt KNO3- 302wt NaNO2 binary system
The similar analysis was applied to No1 salt to find out the reason for the presence of a
small peak adherent to the main melting peak before the melting point Sodium nitrate and
potassium nitrate binary system was synthesized based on the weight fraction of these two
constituent salts in No 1 salt DSC plot for the sodium nitrate-potassium nitrate binary system in
Fig 613 with the converted composition which is essentially same as that in the No1 ternary
system shows smooth heat flow curve before the melting peak which means the solid transition
peak in ternary is not simply relative to the binary system Assumption was made that the solid
44
phase transformation peak in the ternary salt is resulted from a multiple effect ie the
combination of one of the eutectic binary system involved in the ternary salt mixture and the
other binary system which is composed of the rest components The statement is verified that the
small peak in salt 1 is mainly caused by the solid phase transformation peak in lithium nitrate-
potassium nitrate eutectic binary system given the similar shape of the DSC plots in Fig 614
Since in salt No1 there is excess amount of sodium nitrate to form the lithium nitrate-sodium
nitrate binary system the rest sodium nitrate can interact with potassium nitrate and form new
sodium-potassium nitrate system which is shown in fig615 Besides a solid phase
transformation peak is observed in fig615 which has a very small area and won‟t change the
shape of phase transformation peak in fig614 when these two binary systems are combined and
form salt 1 The enthalpies of solid state transformation in two binary salts were also converted
to that in salt 1 by using the weight fractions occupied by both binary systems The difference
of the change of converted enthalpies between the lithium-potassium nitrate eutectic binary and
ternary system is filled by the binary mixture which is composed of the rest components sodium
nitrate-potassium nitrate The comparable converted values of enthalpy change between salt 1
and its two constituent binary systems further verify the assumption that the solid phase
transformation happened in salt 1 is mainly due to the combined effect of LiNO3-KNO3 eutectic
binary system and NaNO3-KNO3 binary system
45
Figure613 DSC plot of 270wt NaNO3-730wt KNO3 binary system
Figure614 DSC plot of 458wtLiNO3-542wtKNO3 binary system
46
Figure615 DSC plot of 460wt NaNO3-540wt KNO3 binary system
Unlike those discussed mixtures above salt No2 Salt No4 Salt No5 and Salt No6 have
only one relatively board melting peak and the heat flow curve before and after are very stable
Similarly there is no solid transformation peaks observed in salt No3 salt No7 and salt No8
However the heat flow after the melting peak in these cases are not stable and the main
endothermic peak is followed by a small hump which is considered to be the recrystallization
process once the compound entered into the liquid state When the process is finished the heat
flow curve returns to steady state
Heating rate is a significant parameter when collect the heat flow curves by using DSC
technique Fig 616(a) and Fig 616(b) illustrate the difference of melting point for salt No6 due
to the change of heating rate If the heating rate is 20oCmin the peak temperature and onset
temperature for the melting peak is 9669oC and 9221
oC respectively Once the heating rate is
decreased to 5oCmin these two temperatures will also be lowered to 9614
oC and 9190
oC The
difference is resulted from the diverse amount of thermal resistance between the testing sample
and the furnace inside the DSC instrument [75] Under higher heating rate the decisive thermal
47
resistance is raised due to the low thermal conductivity medium between the furnace and the
actual sample The insensitivity of gas heat conduction medium in DSC results each unit of
temperature increase on one side cannot have an immediate response on the other side of the gas
Consequently the sample holder which is connected the furnace has a higher temperature than
that inside the sample In this condition the value of temperature profile collected as the sample
holder temperature is larger than the actual temperature The deviation will be much smaller
when the heating rate is reduced In the case the thermal resistance will be decreased because of
the lower temperature gradient of the gas medium in the heating process As a result of that the
collected temperature from the sensor attached to the sample holder will be very close to the
actual temperature inside the testing sample
Figure 616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 20oCmin
heating rate
48
Figure 616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 5oCmin
heating rate
Besides the difference of temperature while using higher and lower heat rate the solution
of DSC will also be affected by different heating rate Fig 617(a) shows the DSC plot for salt
No 7 using the heating rate as 5oCmin and the DSC plot in Fig 617(b) is collected under the
heating rate as 20oCmin It can be observed that in the lower heating rate two small separated
peaks can be viewed as two parts of the solid phase transformation process while in Fig 617(b)
two small peaks before the melting peak merge and present as a board hump The qualification
of resolution can be executed by the term named resolution factor RMKE which is calculated as
the ratio of the peak heat flow value of the separated peaks to that of the concave point between
two peaks The equation for determining RMIKE is given in Eq 27 [76 77]
RMIKE =hpeakhmin [27]
49
Figure 617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 5oCmin
heating rate
Figure 617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 20oCmin
heating rate
In the case of lower heating rate the RMKE is determined to be 15 and the value for higher
heating rate is not available because the concave point of heat flow doesn‟t exist from
Fig617(b) Since the higher RMKE value indicates better resolution it can be stated that the
50
lower heating rate also results in greater sensitivity of the equipment to pick up any small
endothermic peaks
Besides the down-selected 9 compounds some more salt mixtures were also tested Most
of them were not selected to the final candidate for the thermal energy storage application
because of their higher melting point Table 64 gives some of the trial systems measured with
DSC technique It is illustrated that the melting points of mixtures with lower or even no content
of lithium nitrate turn out to be higher than those with sufficient amount of lithium nitrate For
most of the mixtures with melting point lower than 120oC the amount of lithium nitrate should
be larger than 81wt Also all of the systems in table 64 with lithium nitrate less than 15wt
have melting point higher than 140oC Based on the observation above it is concluded that the
lithium nitrate can be used as an additive to bring the melting point down for thermal energy
storage systems
51
Table 64 Melting points of candidate systems as function of temperatures
System Composition (wt)
Onset
Temp
Peak
Temp
(oC) (
oC)
LiNO3 ndash NaNO3 ndash KNO2 107 459 434 890 910
LiNO3 - KNO3 - NaNO2 196 564 241
1024 1046
LiNO3 - NaNO3 - KNO3 - KNO2 90 423 337 151
930 960
LiNO3 - NaNO3 - NaNO2 - KNO2 81 454 65 401
900 910
LiNO3 - KNO3 - NaNO2 - KNO2 193 546 237 24
992 1003
LiNO3 - KNO3 - NaNO2 ndash Mg(NO3)2 193 559 238 09
1010 1020
LiNO3 - NaNO3 - KNO3 - Mg(NO3)2
- MgK 154 172 324 83 267 834 892
LiNO3 - NaNO3 - KNO2 ndash Ca(NO3)2 14 390 333 263
1250 1470
NaNO3 - KNO3 - NaNO2 - KNO2 425 163 71 341
1407 1447
NaNO3 - KNO3 - KNO2 ndash Mg(NO3)2 432 146 380 42
1386 1421
NaNO3 - NaNO2 - KNO2 - Ca(NO3)2 451 92 410 48
1150 1390
LiNO3 - NaNO3 - NaNO2 - KNO2 -
Ca(NO3)2 15 393 37 323 232 1380 1480
LiNO3 - NaNO3 - KNO2 - Ca(NO3)2 -
Mg(NO3)2 14 379 313 275 20 1339 1534
62 Heat capacity determination
621 Heat capacity calibration
DSC was also calibrated for the heat capacity measurement Lithium nitrate sodium
nitrate and potassium nitrate were examined for the heat capacities from room temperature to
upper limit temperature for the instrument In liquid state the heat capacity values for each salt
can be fit to straight line with trace amount of increasing trend Since the temperature range from
the onset temperature of liquid state to the upper limit of DSC is relatively small the heat
capacity values for pure individual salts can be viewed as constants The comparison between the
theoretical and experimental heat capacity data is given in Table 65 Except lithium nitrate the
52
experimental heat capacities data for the rest two systems are almost same as the literature Even
for lithium nitrate which demonstrates the biggest difference from the literature data the 28
vibration is still within a reasonable range
Table 65 Calibration data of heat capacities with different samples
Sample Lit Cp Expt Cp
JgK JgK
LiNO3 218 212
NaNO3 169 167
KNO3 140 139
622 Results
The materials used in the heat capacity measurements are the same as those in the melting
point experiments Molar heat capacities of the all compound were measured by the DSC
equipment from room temperature to 62315 K The heat flow is recorded as a function of
temperature in ldquoiso-scan-isordquo steps at intervals of 20 K The bdquoiso stage‟ refers to isothermal
holding at a particular temperature bdquoscan stage‟ refers to the heat flow recording at a heating rate
of 5 K min1
up to a an increment of 25 K followed by another isothermal holding stage This is
a standard procedure followed in the measurement of heat capacity of materials using the DSC
equipment [63 64] This procedure of heat capacity measurement has two advantages (i) any
heat fluctuations during the recording are avoided by the isothermal steps and (ii) any phase
transition can be highlighted by the choice of temperature range The absolute heat flow to the
sample is determined by subtracting the heat flow collected by running a baseline curve with an
empty pan Because the heat capacity measurement in the heating process corresponds to
53
collecting the value of required heat flow at each temperature all the heat capacity plots have the
same shape with that of heat flow in the melting point measurements Take the heat capacity plot
of LiNO3-NaNO3-KNO3 ternary system as an instance which is shown in fig 618 the heat
capacity curve also has two different peaks The first little peaks corresponds to one occurs at
39027K which was observed in fig 63 the second large and sharp peak happened right after the
small one is prevalent to the endothermic peak with the peak temperature as 39027 K Similarly
after the phase transformation the heat capacity in liquid state becomes very stable and increase
with temperature linearly with little slope
Fig 618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system as function of
temperature
The heat capacity change as function of temperature for salt No1 was illustrated in fig
619 Based on the trend of heat capacity in the liquid state any value for the system in the liquid
can be extrapolated The expressions for heat capacity in liquid state for the new molten salt
systems were discussed and given in the next sectionTable66 shows the specific heat capacity
54
of the all the selective compounds measured at 62315 K and extrapolated at 77315K Besides
the molar heat capacities at 77315K are given in Table 66 of all the salts
Fig 619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K
Table 66 Heat capacity of selected new TES molten salt mixtures
System Expt (62315K) Extrapolated(77315K) Extrapolated(77315K)
Cp JgK Cp JgK Molar Cp JmolK
Salt 1 153 170 1521
Salt 2 143 168 1515
Salt 3 148 155 2183
Salt 4 153 166 1411
Salt 5 153 170 1440
Salt 6 151 163 1435
Salt 7 156 167 1443
Salt 8 155 168 1410
Salt 9 161 170 1937
55
623 Thermodynamic properties
The standard thermodynamic properties such as entropy enthalpy and Gibbs energy for
salt mixtures are determined from the experimental data of melting point and heat capacity in the
temperature range of the present study and expression for determining these properties are given
in equation 28-30 In thermodynamics all these three properties are related to heat capacity and
its variances with temperature In the studied temperature range (29815K-62315K) they can be
described as expression includes heat capacity
[28]
[29]
[30]
Where Tt is the solid transformation temperature Tmp is the melting point ΔHt is enthalpy of
solid phase transformation and ΔHfusion is enthalpy of fusion The standard thermodynamic
properties entropy enthalpy and Gibbs energies as function of temperature for each compound
are expressed in the following section
6231 LiNO3-NaNO3-KNO3 (Salt 1)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3
compound (i) solid state 1 (32315-38415) K (ii) liquid state (40315-62315) K Accordingly
56
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62311 Heat capacity of solid state 1 (29815-38415) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the solid state 1 in the
temperature range of 29815 to 38415 K is fit to a second order polynomial equation Eqn (31)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[31]
( ) K
R2 = 0982
62312 Heat capacity of liquid state (40315-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a linear equation Eqn (32) gives the linear
equation along with the least square fit parameter (R2) in the temperature range for the liquid
state of the compound
JKmol [32]
57
R2 = 0947
Heat capacity data of the LiNO3-NaNO3-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62313 Thermodynamic properties of solid state 1(29815-38415) K
JKmol [33]
Jmol [34]
[35]
Jmol
62314 Thermodynamic properties of liquid state 2(40315-62315) K
[36]
58
JKmol
Jmol [37]
[38]
Jmol
Among the equations above equation (33)-(35) refer to the thermodynamic properties for
solid state equations (36)-(38) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature ranges for solid and liquid state are
given in Table A1 and A2 in appendix A respectively with the corresponding heat capacity as
function of temperature
6232 NaNO3-NaNO2-KNO3 (Salt 2)
The heat capacity data can be divided into two sections for NaNO3-NaNO2-KNO3
compound (i) solid state 1 (32315-39215) K (ii) liquid state (41315-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62321 Heat capacity of solid state 1 (29815-39215) K
59
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the solid state in the
temperature range of 29815 to 39215 K is fit to a second order polynomial equation Eqn (39)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[39]
( ) K
R2 = 0978
62322 Heat capacity of liquid state (40315-62315) K
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a second order polynomial equation Eqn (40)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[40]
R2 = 0941
60
Heat capacity data of the NaNO3-NaNO2-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62323 Thermodynamic properties of solid state 1(29815-39215) K
JKmol [41]
Jmol [42]
[43]
Jmol
62324 Thermodynamic properties of liquid state 2(40315-62315) K
JKmol [44]
61
Jmol [45]
[46]
Jmol
Among the equations above equation (41)-(43) refer to the thermodynamic properties for
solid state equations (44)-(46) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table B1 and B2 in appendix B respectively with the corresponding heat capacity as
function of temperature
6233 LiNO3-NaNO3 -KNO3-MgK (Salt 3)
The heat capacity data can be divided into two sections for LiNO3-NaNO3 -KNO3-MgK
compound (i) solid state 1 (29815-36415) K (ii) liquid state (42115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62331 Heat capacity of solid state 1 (29815-36415) K
62
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the solid state in the
temperature range of 29815 to 36415 K is fit to a second order polynomial equation Eqn (47)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[47]
( ) K
R2 = 0995
62332 Heat capacity of liquid state (42115-62315) K
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the liquid state in the
temperature range of 42115 to 62315 K is fit to a second order polynomial equation Eqn (48)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[48]
R2 = 0963
63
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
62333 Thermodynamic properties of solid state 1(29815-36415) K
JKmol [49]
Jmol [50]
[51]
Jmol
62334 Thermodynamic properties of liquid state 2(42115-62315) K
64
JKmol [52]
Jmol [53]
[54] [29]
Jmol
Among the equations above equation (49)-(51) refer to the thermodynamic properties for
solid state equations (52)-(54) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table C1and C2 in appendix C respectively with the corresponding heat capacity as
function of temperature
6234 LiNO3-NaNO3-KNO3-NaNO2 (Salt 4)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-NaNO2
compound (i) solid state 1 (29815-36315) K (ii) liquid state (38115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62341 Heat capacity of solid state 1 (29815-36315) K
65
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the solid state in the
temperature range of 29815 to 36315 K is fit to a second order polynomial equation Eqn (55)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[55]
( ) K
R2 = 0995
62342 Heat capacity of liquid state (38115-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the liquid state in the
temperature range of 38115 to 62315 K is fit to a second order polynomial equation Eqn (56)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[56]
R2 = 0972
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
66
62343 Thermodynamic properties of solid state 1(29815-36315) K
JKmol [57]
Jmol [58]
[59]
Jmol
62344 Thermodynamic properties of liquid state 2(38115-62315) K
JKmol [60]
Jmol [61]
67
[37]
Jmol [62]
Among the equations above equation (57)-(59) refer to the thermodynamic properties for
solid state equations (60)-(62) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table D1 and D2 in appendix D respectively with the corresponding heat capacity as
function of temperature
6235 LiNO3-NaNO3-NaNO2-KNO3-KNO2 (Salt 5)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-NaNO2-KNO3-
KNO2 compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62351 Heat capacity of solid state 1 (29815-35915) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
in the temperature range of 29815 to 35915 K is fit to a second order polynomial equation Eqn
(63) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
68
[63]
( ) K
R2 = 0996
62352 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the liquid
state in the temperature range of 37515 to 62315 K is fit to a second order polynomial equation
Eqn (64) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[64]
R2 = 0969
Heat capacity data of the LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62353 Thermodynamic properties of Solid state 1(29815-35915) K
JKmol [65]
69
Jmol [66]
[67]
Jmol
62354 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [68]
Jmol [69]
[45]
Jmol [70]
70
Among the equations above equation (65)-(67) refer to the thermodynamic properties for
solid state equations (68)-(70) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table E1 and E2 in appendix E respectively with the corresponding heat capacity as
function of temperature
6236 LiNO3-NaNO3-KNO3-KNO2 (Salt 6)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-KNO2
compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62361 Heat capacity of solid state 1 (29815-36515) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the solid state in the
temperature range of 29815 to 36515 K is fit to a second order polynomial equation Eqn (71)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[71]
( ) K
R2 = 0998
71
62362 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the liquid state in the
temperature range of 37515 to 62315 K is given in Table 20 The data is fit to a second order
polynomial equation Eqn (72) gives the linear equation along with the least square fit parameter
(R2) in the temperature range for the liquid state of the compound
[72]
R2 = 0953
Heat capacity data of the LiNO3-NaNO3-KNO3-KNO2 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62363 Thermodynamic properties of solid state 1(29815-35915) K
JKmol [73]
Jmol [74]
72
[75]
Jmol
62364 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [76]
Jmol [77]
Jmol [78]
Among the equations above equation (73)-(75) refer to the thermodynamic properties for
solid state equations (76)-(78) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
73
given in Table F1 and F2 in appendix F respectively with the corresponding heat capacity as
function of temperature
6237 LiNO3-KNO3-NaNO2-KNO2 (Salt 7)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62371 Heat capacity of solid state 1 (29815-35415) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 1 in
the temperature range of 29815 to 35415 K is fit to a second order polynomial equation Eqn
(79) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[79]
(29815-35415) K
R2 = 0993
62372 Heat capacity of solid state 2 (36215-37315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 2 in
the temperature range of 36215 to 37315 K is fit to a second order polynomial equation Eqn
74
(80) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 2 of the compound
[80]
R2 = 0977
62373 Heat capacity of liquid state (37915-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the liquid state in the
temperature range of 37915 to 62315 K is fit to a linear equation Eqn (81) gives the
polynomial equation along with the least square fit parameter (R2) in the temperature range for
the liquid state of the compound
[81]
R2 = 0961
Heat capacity data of the LiNO3-KNO3-NaNO2-KNO2 compound in the two solid states
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62374 Thermodynamic properties of solid state 1(29815-35415) K
75
JKmol [82]
Jmol [83]
[84]
Jmol
62375 Thermodynamic properties of solid state 2(36215-37315) K
JKmol [85]
Jmol [86]
76
[87] [62]
Jmol
62376 Thermodynamic properties of liquid state (37915-62315) K
JKmol [88]
Jmol [89]
Jmol [90]
Among the equations above equation (82)-(84) refer to the thermodynamic properties for
solid 1 equation (85)-(87) refer to the thermodynamic properties for solid 2 equations (88)-(90)
refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy values
77
in the studied temperature range for solid 1 solid 2 and liquid state are given in Table G1-G3 in
appendix G respectively with the corresponding heat capacity as function of temperature
6238 LiNO3-KNO3-NaNO2-Mg(NO3)2 (salt 8)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62381 Heat capacity of solid state 1 (29815-33715) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid
state 1 in the temperature range of 29815 to 33715 K is fit to a second order polynomial
equation Eqn (91) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the solid state 1 of the compound
[91]
(29815-33715) K
R2 = 0994
62382 Heat capacity of solid state 2 (36115-36415) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid state 2
in the temperature range of 36115 to 36415 K is given in Table 4 The data is fit to a second
78
order polynomial equation Eqn (92) gives the polynomial equation along with the least square
fit parameter (R2) in the temperature range for the solid state 2 of the compound
[92]
R2 = 0992
62383 Heat capacity of liquid state (41115-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the liquid state in
the temperature range of 41115 to 62315 K is given in Table 5 The data is fit to a linear
equation Eqn (93) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the liquid state of the compound
[93]
R2 = 0934
Heat capacity data of the LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the two solid
states follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62384 Solid state 1(29815-35415) K
79
JKmol [94]
Jmol [95]
[96]
Jmol
62385 Solid state 2(36115-36415) K
JKmol [97]
80
Jmol [98]
[99] [74]
Jmol
62386 Liquid state (41115-62315) K
JKmol [100]
Jmol [101]
Jmol [102]
Among the equations above equation (94)-(96) refer to the thermodynamic properties for
solid 1 equation (97)-(99) refer to the thermodynamic properties for solid 2 equations (100)-
(102) refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy
81
values in the studied temperature range for solid 1 solid 2 and liquid state are given in Table H1
and H2 in appendix H respectively with the corresponding heat capacity as function of
temperature
6239 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK(Salt 9)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-
Mg(NO3)2-MgK compound (i) solid state 1 (29815-35315) K (ii) liquid state (39115-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62391 Heat capacity of solid state 1 (29815-35315) K
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state in the temperature range of 29815 to 35315 K is fit to a second order polynomial equation
Eqn (103) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[103]
( ) K
R2 = 0996
62392 Heat capacity of liquid state (39115-62315) K
82
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the liquid
state in the temperature range of 39115 to 62315 K is fit to a second order polynomial equation
Eqn (104) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[104]
R2 = 0951
Heat capacity data of the LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62393 Solid state 1(29815-35315) K
JKmol [105]
Jmol [106]
83
[107]
Jmol
62394 Liquid state 2(39115-62315) K
JKmol [108]
Jmol [109]
[110]
Jmol
Among the equations above equation (105)-(107) refer to the thermodynamic properties
for solid state equations (108)-(110) refer to thermodynamic properties of the liquid The
entropy enthalpy and Gibbs energy values in the studied temperature range for solid and liquid
state are given in Table I1 and I2 in appendix I respectively with the corresponding heat
capacity as function of temperature
84
624 Discussion of Gibbs energy change for molten salts
The Gibbs energy change data as function of temperature for 9 systems are given in fig
620 and the values at 62315K are shown in Table 67 Every system demonstrates continuous
curve throughout the whole studied temperature range Most of systems have similar Gibbs
energy change values for each temperature spot due to the comparable compositions and
properties of constituent salts However salt 3 and salt 9 Both of these salts have certain
amount of MgKN compound which presents large absolute amount of change of Gibbs energy in
the same studied temperature range [66] Since the change of Gibbs energy for multi-component
mixture is relevant to that of each constituent salt the large absolute value of ΔG of MgKN
mainly contributes to the largely negative value of salt 3 and salt 9 shown in fig 620 Besides
it is observed that most systems contain nitrite salts present lower absolute value of Gibbs energy
change For example salt 1 doesn‟t include any nitrite salt and has a relatively high absolute
value of Gibbs energy change as 1704kJmol while other systems having nitrite salts show lower
value varies from 1372kJmol to 1592kJmol
85
Fig 620 Change of Gibbs energy as function of temperature for molten salt systems
Table 67 Change of Gibbs energy values at 62315K for molten salt systems
SNo System ΔG(kJmol)
1 LiNO3-NaNO3-KNO3 1704
2 NaNO3- NaNO2- KNO3 1372
3 LiNO3- NaNO3- KNO3- MgKN 2807
4 LiNO3- NaNO3- KNO3- NaNO2 1443
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1441
6 LiNO3-NaNO3-KNO3-KNO2 1570
7 LiNO3-KNO3-NaNO2-KNO2 1592
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1583
9 LiNO3-NaNO3-KNO3-Mg(NO3)2 -MgKN 2217
86
63 Density determination
631 Density calibration
Several pure molten salts are used to calibrate the density measurement set-up before the
actual density measurement All the density values decrease as function of temperature in the
liquid state and follow the same linear equations as described in eq 4 The experimental values
at 350oC for KNO3 NaNO3 and LiNO3 are selected to compare with the literature data at the
same temperature The results are shown in Table 68 Based on the comparison of the literature
data and the experimental data the variation of density for molten nitrate salt is within in 4
Table 68 Calibration of density measurements with different pure nitrate salts
Sample Literature density Experimental density
gcm3 gcm
3
LiNO3 1727 1701
NaNO3 2066 2144
KNO3 1860 1855
632 Results and discussions
The density result of the salt as function of temperature is plotted for all the salts in Figure
621 and Figure 622 It is observed that the temperature dependence of density above the
melting point is different from that in solid state As known in solid state the density of salt has
an exponential relation with temperature while in these liquid cases the density values have
linearly dependence with temperature The stable variation as function of temperature allows the
extrapolation of density at even higher temperature The regression analysis is performed to get
the coefficient used for describing eq 4 and the results for the coefficients are shown in
87
Table69 [78-80] It is observed that the change of composition is implied on the coefficient A
which indicates the initial point at 150oC The temperature dependence coefficient B doesn‟t
change much with composition which may be mainly affected by the group of anion and cation
Table 69 Coefficient A and B for density determination of salt 1-salt 9
Salt No System A Btimes10
3
(gcm3) (gcm
3degC)
1 LiNO3-NaNO3-KNO3 2032 0493
2 NaNO3- NaNO2- KNO3 2081 0570
3 LiNO3- NaNO3- KNO3-MgKN 2055 0526
4 LiNO3- NaNO3- KNO3- NaNO2 2033 0520
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 2018 0485
6 LiNO3-NaNO3-KNO3-KNO2 2060 0554
7 LiNO3-KNO3-NaNO2-KNO2 2048 0554
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 2044 0524
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 2060 0566
Figure 621 The densities of the salt 1-salt 5 as function of temperature
88
In figure 621 all the density values are clustered around 198gcm3 at 150
oC to
186gcm3 at high temperature end and the deviation of density between all the mixtures is within
in 0047g cm3 Among all the salt mixtures the NaNO3-NaNO2-KNO3 ternary system
demonstrates the highest density value throughout the studied temperature range and LiNO3-
NaNO3-KNO3 ternary system LiNO3- NaNO3-KNO3-NaNO2 quaternary system and LiNO3-
NaNO3-KNO3-NaNO2-KNO2 quinary system show densities at the bottom side of Fig 621 For
salt 2 which doesn‟t contain any lithium nitrate the density at every selected temperature spot
is obviously higher than that of salt 1 4 and 5 which have large amount of lithium nitrate
Moreover the salt 3 which contains the relatively small amount of lithium nitrate stays in
between of salt 1 and salt 2 This comparison illustrates that the addition of lithium nitrate has
an offsetting effect on density for molten salt and it is consistent with previous literature reports
[81] The four systems presented in figure 622 also show even closer density values in the
studied temperature range Similarly salt 6 which contains the least lithium nitrate has the
largest density Salt 7 and salt 8 have almost same composition for the three dominating
components as a result of that the density curves for both mixtures are determined by the same
regression coefficient A and B Moreover the larger amount of lithium nitrate involved in these
two salt mixtures contributes to the lower density given in figure622 which further verifies the
significantly offsetting effect of lithium nitrate on density
89
Figure 622 The densities of the salt 6-salt 9 as function of temperature
The salt mixtures with maximum and minimum amount of lithium nitrate were plotted and
compared with equimolar NaNO3-KNO3 binary system and pure KNO3 salt in Fig623 [82 83]
It is observed that the NaNO3-KNO3 binary system has very similar density value to that of salt
2 because of the analogous type and composition of component in both salts The density of
pure KNO3 is slightly lower than the binary salt mixture which indicates the density of NaNO3 is
close to but higher than KNO3 in the studied temperature range Salt 1 shows the lowest density
in Fig623 due to the offsetting effect on density caused by lithium nitrate which has been
discussed above
90
Figure 623 Density of the salt 1 salt 2 as function of temperature compared to the
equimolar NaNO3-KNO3 binary system and pure KNO3
64 Thermal energy storage density of molten salts
The energy density which is considered as one of the most significant parameters of TES
application can be evaluated by calculation based on the measured density heat capacity and
working temperature range The equation of the thermal energy storage density (E) at working
temperature of 500oC is expressed in equation 111
E = Cp (500-Tm) [111]
Where Cp and are extrapolated heat capacity and density at 500oC respectively Tm is
melting point for salt mixture The extrapolation of density and heat capacity is based on the
linear temperature dependence for both parameters in molten state and the values are shown in
Table 610
91
Table 610 Extrapolated value of density and heat capacity at 500oC of salt 1-salt 9
Salt
No System
Density Heat Capacity
(gmL) (JgK)
1 LiNO3-NaNO3-KNO3 1785 170
2 NaNO3- NaNO2- KNO3 1796 168
3 LiNO3-NaNO3-KNO3-MgK 1773 155
4 LiNO3- NaNO3- KNO3- NaNO2 1792 166
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1796 170
6 LiNO3-NaNO3-KNO3-KNO2 1783 163
7 LiNO3-KNO3-NaNO2-KNO2 1771 167
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1782 168
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 1777 170
The calculated energy density for each salt is given in Table 611 compared with that of
solar salt (NaNO3-KNO3) All the new synthesized salt mixtures have significantly higher energy
density than solar salt and salt 3 shows the highest energy density among the new salts
Although salt 1 has higher heat capacity and good melting point the energy density is still the
lowest among new salt mixtures given by the effect of low density The conclusion can be drawn
from these observations that the energy density is a property affected by multiple parameters and
every part plays an important role in determining the efficiency of energy storage of salt
mixtures
92
Table 611 Energy density of salt 1-salt 9 compare to solar salt
The gravimetric storage density of new molten salts are listed in Table 612 and compared
with those different storage systems in fig 624 It is found that in the parabolic trough working
temperature range the gravimetric storage densities of new molten salts are located on the higher
side Even though some reported sensible energy storage liquids have larger gravimetric density
values than the new salts the maximum working temperatures reveal the instable working
condition at 500oC Taking conversion efficiency thermal stability and gravimetric storage
density into considerations the new molten salts are the most suitable choices of the sensible
heat storage for parabolic trough application
Salt No System Energy Density
500degC (MJm3)
0 NaNO3- KNO3 756
1 LiNO3-NaNO3-KNO3 1162
2 NaNO3- NaNO2- KNO3 1135
3 LiNO3-NaNO
3-KNO
3-MgKN 1099
4 LiNO3- NaNO
3- KNO
3- NaNO
2 1189
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1232
6 LiNO3-NaNO3-KNO3-KNO2 1174
7 LiNO3-KNO3-NaNO2-KNO2 1183
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1192
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 1242
93
Fig 624 Gravimetric storage density comparison of different energy storage systems as
function of temperature
Table 612 Gravimetric storage densities for solar salt and new molten salts
Salt
No System
Gravimetric Storage Density
500degC (kJkg)
0 NaNO3- KNO3 404
1 LiNO3-NaNO3-KNO3 560
2 NaNO3- NaNO2- KNO3 533
3 LiNO3-NaNO
3-KNO
3-MgKN 575
4 LiNO3- NaNO
3- KNO
3- NaNO
2 612
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 595
6 LiNO3-NaNO3-KNO3-KNO2 594
7 LiNO3-KNO3-NaNO2-KNO2 604
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 610
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 649
94
CHAPTER 7
CONCLUSION
The melting points of new molten salts were experimentally determined using DSC
Different from metals the melting point was chosen as the peak temperature rather than onset
temperature of the endothermic peak due to the low thermal conductivity and broad phase
transition range of the molten nitride salt mixture All of the nine new molten salts have melting
points from 89oC to 124
oC which are much lower than current sodium-potassium binary solar
salt Some systems such as salt No1 No7 and No8 have solid phase transformation observed
from the DSC plots It is found that the phase transformations of salt No 7 and No 8 are mainly
contributed to the KNO3-NaNO2 binary system while the small solid transformation peak of salt
No1 is resulted from the combined effect of the KNO3-LiNO3 eutectic binary system involved in
the ternary salt and another binary system which is composed of the rest components The
heating rate of DSC was revealed as a significant parameter for the any endothermic peak
determination When using lower heating rate the thermal resistance between the studied sample
and the furnace will be minimal and the resolution of peak detection will be enhanced
The heat capacities of all the multi-component salts (1 to 9) were determined using DSC
and found varying from 143 to 161 JgK at 350oC The heat capacity in the liquid state
demonstrates linear increase trend as function of temperature On the basis of that the heat
capacity was extrapolated to parabolic trough operating temperature of 500oC Besides heat
capacity data as function of temperature are fit to polynomial equation and thermodynamic
95
properties like enthalpy entropy and Gibbs energies of the compound as function of temperature
are subsequently deduced
Experimental measurements of density of multi-component systems were conducted as
function of temperature in their liquid state In liquid state the density values decrease linearly
as temperature increases The results of those mixtures were compared to the solar salt and
individual constituent salts The comparison demonstrates that the addition of lithium nitrate
lowers the density which is consistent with the observation that lithium nitrate has the lowest
density among all the individual salts in the studied temperature range On the basis of densities
heat capacities and the melting points energy storage density for all the new salts were
calculated and compared to the binary solar salt Among all the new molten salt systems
LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN quinary system (salt 9) presents the largest thermal
energy storage density as well as the gravimetric density values Moreover the larger thermal
energy storage as well as gravimetric storage densities compared to the solar salt indicate the
better energy storage capacities of new salts for solar power generation systems
96
REFERENCES
[1] JF Manwell JG McGowan and AL Rogers Wind Energy Explained-Theory Design and
Application second edition John Wiley and sons Ltd UK 2009
[2] MJ Pasqualetti Morality space and the power of wind-energy landscapes Geographical
Review 90 2000 381-394
[3] DG Fink and HW Beaty Standard Handbook for Electrical Engineers Eleventh Edition
McGraw-Hill New York 1978
[4] R Bertani Geothermal Energy An Overview on Resources and Potential Proceedings of the
International Conference on National Development of Geothermal Energy Use 2009 Slovakia
[5] TA Volk LP Abrahamson EH White E Neuhauser E Gray C Demeter C Lindsey J
Jarnefeld DJ Aneshansley R Pellerin and S Edick Developing a Willow Biomass Crop
Enterprise for Bioenergy and Bioproducts in the United States Proceedings of Bioenergy
2000 October 15-19 2000 Buffalo New York USA
[6] M Asplund N Grevesse and AJ Sauval The new solar abundances-Part I the
observations Communications in Asteroseismology 147 2006 76-79
[7] DRWilliams Sun Fact Sheet NASA 2004
httpnssdcgsfcnasagovplanetaryfactsheetsunfacthtml
[8] U Herrmann Survey of Thermal Energy Storage for Parabolic Trough Power Plants Journal
of Solar Energy Engineering 124 2002 145-152
[9] Rocket Research Company Chemical energy storage for solar thermal conversion SAND79-
8198 Livermore Sandia National Laboratories 1979
97
[10] A Steinfeld and R Palumbo Solar thermochemical process technology Encyclopedia of
Physical Science and Technology 2001 237-256
[11] EA Fletcher Solar thermal processing a review Journal of Solar Energy Engineering
2001 63-74
[12] R W Bradshaw and Nathan P Siegel Molten Nitrate Salt Development for Thermal
Energy Storage in Parabolic Trough Solar Power Systems of the Energy Sustainability 2008
Conference August 10-14 2008 Jacksonville Florida USA
[13] B Kelly H Price D Brosseau and D Kearney Adopting NitrateNitrite Salt Mixtures as
the Heat Transport Fluid in Parabolic Trough Power Plants Proceedings of the Energy
Sustainability 2007 Conference June 27-30 2007 Long Beach CA
[14] H Reilly and G Kolb Evaluation of Molten Salt Power Tower Technology Based on
Experience at Solar Two SAND2001-3674 Sandia National Laboratories 2001
[15] T Wendelin ldquoParabolic Trough VSHOT Optical Characterization in 2005-2006rdquo NREL
wwwnrelgovdocsfy06osti40024pdf
[16] RB Diver C Andraka S Rawlinson V Goldberg and G Thomas The Advanced Dish
Development System Project ASME Proceedings of Solar Forum 2001 Washington DC
[17] S D Odeh G L Morrison and M Behnia Modelling of parabolic trough direct steam
generation solar collectors Solar Energy 62 1998 396-406
[18] V Heinzel H Kungle and M Simon Simulation of a parabolic trough collector ISES
Solar World Congress Harare Zimbabwe 1-10
[19] S D Odeh G L Morrison and M Behnia Modeling of Parabolic Trough Direct
Generation Solar Collectors Solar Energy 62 1998 395-406
[20] Ezzat Optimum Working Fluids for Solar Powered Rankine Cycle Cooling of Buildings
Solar energy 25 1980 235-241
98
[21] R G Reddy Ionic Liquids How well do we know them editorial Journal of Phase
Equilibria and Diffusion 27 2006 210-211
[22] M Zhang and R G Reddy Application of [C4min][Tf2N] Ionic Liquid as Thermal
Storage and Heat Transfer Fluids editor J Weidner ECS Transactions 2 (28) 2007 27-32
[23] M Zhang and R G Reddy Evaluation of Ionic Liquids as Heat Transfer Materials in
Thermal Storage Systems Energy Energy Materials editors F Dogan M Awano D Singh
and B Tuttle ASM International Materials Park Ohio USA MSampT‟07 2007 151-160
[24] R G Reddy Novel Applications of Ionic Liquids in Materials Processing Advanced
Structural and Functional Materials Design 2008 Journal of Physics Conference Series (JPCS)
165 2009 1-6
[25] RW Bradshaw and DE Meeker High-temperature stability of ternary nitrate molten
salts for solar thermal energy systems Solar Energy Materials 21 1990 51-60
[26] AS Trunin Designing and investigations of salt systems for solar energy utilization
Utilization of sun and other radiation sources in materials research Kiev Naukova Dumka 1983
p 228-38
[27] D J Rogers and G J Janz Melting-crystallization and premelting properties of sodium
nitrate-potassium nitrate Enthalpies and heat capacities Journal of Chemical and Engineering
Data 27 1982 424-428
[28] D Kearney U Herrmann P Nava and B Kelly Assessment of a molten salt heat transfer
fluid in a parabolic trough solar field Journal of Solar Energy Engineering 125 2003 170-176
[29] Q Peng J Ding X Wei J Yang and X Yang The preparation and properties of multi-
component molten salts Applied Energy 87 2010 2812-2817
[30] E M Levin C R Robbins and H F McMordie Phase Diagrams for Ceramists American
Ceramic Society 1964
[31] J C Oxley J L Smith E Rogers and M Yu Ammonium nitrate thermal stability and
explosivity modifiers Thermochimica Acta 384 2002 23-45
99
[32] LG Marianowski and HC Maru Latent heat thermal energy storage systems above
4508oC Proceedings of 12th intersociety energy conversion engineering conference 1977 55-
66
[33] HC Maru JF Dullea A Kardas L Paul LG Marianowski E Ong et al Molten salts
energy storage systems Chicago Final Report of the Institute of Gas Technology 1978
[34] WM Philips and JW Stears Advanced latent heat of fusion thermal energy storage for
solar power stations Proceedings of 20th intersociety energy conversion engineering conference
2 1985 384-391
[35] KE Mayo Heat source systems USA Patent 3605720 1971
[36] JI Eichelberger and HD Gillman Investigation of metal fluoride thermal energy storage
material Proceedings of 12th intersociety energy conversion engineering conference 1977 567-
574
[37] GR Heidenreich and MB Parekh Thermal energy storage for organic Rankine cycle solar
dynamic space power systems Proceedings of 21st intersociety energy conversion engineering
conference 2 1986 791-797
[38] IK Garkushin AC Trunin TT Miftakhov and MA Dibirov Salt heat storage
composition USSR Patent 1036734 1983
[39] W M Philips and J W Stears Advanced latent heat of fusion thermal energy storage for
solar power stations In Proceedings of 20th intersociety energy conversion engineering
conference 2 1985 384-391
[40] Y Takahashi M Kamimoto Y Abe R Sakamoto K Kanari and T Ozawa Investigation
of latent heat-thermal energy storage materials IV Thermoanalitical evaluation of binary eutectic
mixtures of NaOH with LiOH or KOH Thermochim Acta 121 1987 193-202
[41] C E Birchenall and A F Riechman Heat storage in eutectic alloys Metall Trans A
11A(8) 1980 1415-1420
100
[42] Y Takahashi R Sakamoto and M Kamimoto Heat capacities and latent heats of LiNO3
NaNO3 and KNO3 International Journal of Thermophysics 9(6) 1988 1081-1090
[43] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate Mixtures
Journal of Chemical Engineering Data 8(3) 1963 469
[44] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical Engineering Data 6 (4) 1961 493
[45] GF Petersen WA Ewing and G P Smith Densities of Some Salt Mixtures Journal of
Chemical Engineering Data 6 (4) 1961 540
[46] G J Janz and M R Lorenz Precise Measurement of Density and Surface Tension at
Temperatures up to 1000degC in One Apparatus Review of Scientific Instruments 31 (1) 1960
18-23
[47] G J Janz C B Allen N P Bansal R M Murphy and R P Tomkins Physical Properties
Data Compilations Relevant to Energy Storage II Molten Salts Data on Single and Multi-
Component Salt Systems National Bureau of Standards NSRDS-NBS 61 Part II April 1979
[48] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation Equations
for Critically Evaluated Density Surface Tension Electrical Conductance and Viscosity Data
Journal of Physical and Chemical Reference Data 17 1988 2
[49] A T Ward and G J Janz Molten Carbonate Electrolytes Electiral Conductance Density
and Surface Tension of Binary and Ternary Eleclrochimica Acta 10 1965 849-857
[50] Y Takahashi R Sakamoto and MKamimoto Heat Capacities and Latent Heat of LiNO3
NaNO3 amp KNO3 International Journal of Thermophysics 9 1998 1081-1090
[51] R W Carling Heat capacities of NaNO3 and KNO3 up to 800 K Thermochimica Acta 60
1983 265-275
[52] Y Takahashi Latent heat measurement by DSC with sapphire as standard material
Thermochim Acta 88(1) 1985 199-204
101
[53] GW Hohne W Hemminger and HJ Flammersheim Differential Scanning Calorimetry
Springer-Verlag Berlin 1996
[54] W Hemminger and G Hohne Calorimetry Fundamentals and Practice Verlag Weinheim
1984
[55] M Merzlyakov and C Schick Thermal conductivity from dynamic response of DSC
Thermochimica Acta 377 2001 183-191
[56] T Kousksou A Jamil S Gibout and Y Zeraouli Thermal analysis of phase change
emulsion Journal of Thermal Analysis and Calorimetry 96 2009 841-852
[57] A Jamil T Kousksou K El Omari Y Zeraouli and Y Le Guer Heat transfer in salt
solutions enclosed in DSC cells Thermochimica Acta 507-508 2010 15-20
[58] MJ Richardson Quantitative aspects of differential scanning calorimetry Thermochimica
Acta 300 1997 15-28
[59] S Rudtsch Uncertainty of heat capacity measurements with differential scanning
calorimeters Thermochimica Acta 382 2002 17-25
[60] M J Maeso and J Largo The phase diagram of LiNO3-NaNO3 and LiNO3-KNO3 the
behavior of liquid mixtures Thermochimica Acta 223 (1993) 145-156
[61] O J Kleppa A new twin high-temperature reaction calorimeter The heats of mixing in
liquid sodium-potassium nitrates Journal of Physical Chemistry 64(12) (1960) 1937-1940
[62] G W H Hhne H K Cammenga W Eysel E Gmelin and W Hemminger The
Temperature Calibration of Scanning Calorimeters Thermochimica Acta 160 1990 1-12
[63] L B Pankratz Thermodynamic Properties of Carbides Nitrides and Other Selected
Substances U S Bureau of Mines Bulletin 696 1994
[64] M Zhang and R G Reddy Thermodynamic properties of C4mim[Tf2N] ionic liquids 0 2
2010 71-76
102
[65] D Mantha T Wang and R G Reddy Thermodynamic Modeling of Eutectic Point in the
LiNO3-NaNO3-KNO3 Ternary System Journal of Phase Equilibria and Diffusion 2011
(accepted)
[66] R G Reddy T Wang and D Mantha Determination of thermodynamic properties of
2KNO3Mg(NO3)2 Thermochimica Acta 2011 (submitted)
[67] T Wang D Mantha and R G Reddy Thermal stability of new LiNO3-NaNO3-KNO3
ternary salt for thermal energy storage system (in preparation)
[68] G D Carvalho E Frollini and W N D Santos Thermal conductivity of polymers by hot-
wire method J Appl Poly Sci 62 (1996) 2281-2285
[69] H Bloom A Doroszkowski and S B Tricklebank Molten salt mixtures IX The thermal
conductivities of molten nitrate systems Aus J Chem 18(8) (1965) 1171-1176
[70] A G Turnbull Thermal conductivity of molten salts Aus J Appl Sci 12 (1961) 30-41
[71] L R White and H T Davis Thermal conductivity of molten alkali nitrates J Chem Phys
47(1967) 5433-5439
[72] M V Peralta-Martinez M J Assael M J Dix L Karagiannidis and W A Wakeham A
Novel Instrument for the Measurement of the Thermal Conductivity of Molten Metal Part1
Instrument‟s Description Int J Thermophysics 27 (2006) 353-375
[73] Y Tada M Harada M Tanlgakl and W Eguchl Laser Flash Method for Measuring
Thermal Conductivity of Liquids Application to Molten Salts Industrial and Engineering
Chemistry Fundamentals 20 1981 333- 336
[74] M V Smirnov V A Khokhlov and E S Filatov Thermal conductivity of molten alkali
halides and their mixtures Electrochimica Acta 32 (1986) 1019-1026
[75] E Marti E Kaisersberger and W D Emmerich NEW ASPECTS OF THERMAL
ANALYSIS Part I Resolution of DSC and means for its optimization Journal of Thermal
Analysis and Calorimetry 77 2004 905-934
103
[76] E Marti E Kaisersberger G Kaiser and WY Ma Netzsch Annual 2000
bdquoThermoanalytical Characterization of Pharmaceuticals‟ Netzsch-Geraumltebau GmbH D-95100
SelbBavaria
[77] P J van Ekeren C M Holl and A J Witteveen A comparative test of differential
scanning calorimeters Journal of Thermal Analysis and Calorimetry 49 1997 1105-1114
[78] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation
Equations for Critically Evaluated Density Surface Tension Electrical Conductance and
Viscosity Data Journal of Physical and Chemical Reference Data 17 1988 1
[79] G F Petersen W A Ewing and G P Smith ldquoDensities of Some Salt Mixturesrdquo Journal of
Chemical and Engineering Data 6 1961 540
[80] P M Nasch and S G Steinemann Density and Thermal Expansion of Molten Manganese
Iron Nickel Copper Aluminum and Tin by Means of the Gamma-Ray Attenuation Technique
Physics and Chemistry of Liquids 29 1995 43-58
[81] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical and Engineering Data 6 1961 493-496
[82] D A Nissen Thermophysical Properties of the Equimolar Mixture NaNO3-KNO3 from
300degC to 600degC Journal of Chemical and Engineering Data 27 1982 269-273
[83] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate
Mixtures Journal of Chemical and Engineering Data 8 1963 469
104
APPENDIX
Appendix A
Table A1 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in solid state
(29815-40315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 342 1290 417 -025
299 027 008 000 343 1317 426 -026
300 059 018 000 344 1345 436 -027
301 091 028 000 345 1372 445 -028
302 123 037 000 346 1399 455 -029
303 154 047 000 347 1427 464 -031
304 186 056 000 348 1454 474 -032
305 217 066 000 349 1481 483 -033
306 248 076 000 350 1508 493 -035
307 279 085 000 351 1535 503 -036
308 310 095 -001 352 1562 512 -038
309 340 104 -001 353 1589 522 -039
310 371 114 -001 354 1616 532 -041
311 401 123 -001 355 1643 541 -042
312 432 133 -002 356 1670 551 -044
313 462 142 -002 357 1697 561 -045
314 492 152 -002 358 1724 570 -047
315 521 161 -003 359 1751 580 -048
316 551 171 -003 360 1777 590 -050
317 581 180 -004 361 1804 600 -052
318 610 190 -004 362 1831 610 -053
319 640 199 -005 363 1858 619 -055
320 669 209 -005 364 1885 629 -057
105
321 698 218 -006 365 1911 639 -059
322 727 228 -007 366 1938 649 -060
323 756 237 -007 367 1965 659 -062
324 785 246 -008 368 1992 669 -064
325 814 256 -009 369 2018 679 -066
326 842 265 -009 370 2045 689 -068
327 871 275 -010 371 2072 699 -070
328 899 284 -011 372 2098 709 -072
329 928 294 -012 373 2125 719 -074
330 956 303 -012 374 2152 729 -076
331 984 313 -013 375 2179 739 -078
332 1012 322 -014 376 2205 750 -080
333 1041 331 -015 377 2232 760 -082
334 1069 341 -016 378 2259 770 -084
335 1096 350 -017 379 2286 780 -086
336 1124 360 -018 380 2312 791 -088
337 1152 369 -019 381 2339 801 -090
338 1180 379 -020 382 2366 811 -093
339 1207 388 -021 383 2393 822 -095
340 1235 398 -022 384 2420 832 -097
341 1263 407 -023 38415 2424 834 -097
Table A2 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in liquid state
(40315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
40315 4287 1565 -163 514 7070 2838 -796
404 4310 1575 -167 515 7094 2850 -803
405 4337 1585 -171 516 7117 2863 -810
406 4363 1596 -175 517 7141 2875 -817
407 4390 1607 -180 518 7165 2887 -824
408 4417 1618 -184 519 7188 2899 -831
409 4443 1629 -189 520 7212 2911 -839
410 4470 1640 -193 521 7235 2924 -846
411 4496 1651 -197 522 7259 2936 -853
412 4523 1662 -202 523 7282 2948 -860
106
413 4549 1672 -206 524 7306 2960 -868
414 4576 1683 -211 525 7329 2973 -875
415 4602 1694 -216 526 7352 2985 -882
416 4629 1705 -220 527 7376 2997 -890
417 4655 1716 -225 528 7399 3010 -897
418 4681 1727 -230 529 7422 3022 -904
419 4708 1738 -234 530 7446 3034 -912
420 4734 1749 -239 531 7469 3047 -919
421 4760 1760 -244 532 7492 3059 -927
422 4786 1771 -249 533 7516 3071 -934
423 4813 1782 -253 534 7539 3084 -942
424 4839 1793 -258 535 7562 3096 -949
425 4865 1804 -263 536 7585 3109 -957
426 4891 1816 -268 537 7608 3121 -965
427 4917 1827 -273 538 7632 3134 -972
428 4943 1838 -278 539 7655 3146 -980
429 4969 1849 -283 540 7678 3158 -988
430 4995 1860 -288 541 7701 3171 -995
431 5021 1871 -293 542 7724 3183 -1003
432 5046 1882 -298 543 7747 3196 -1011
433 5072 1894 -303 544 7770 3208 -1018
434 5098 1905 -308 545 7793 3221 -1026
435 5124 1916 -313 546 7816 3233 -1034
436 5149 1927 -318 547 7839 3246 -1042
437 5175 1938 -323 548 7862 3259 -1050
438 5201 1950 -328 549 7885 3271 -1058
439 5226 1961 -334 550 7908 3284 -1066
440 5252 1972 -339 551 7931 3296 -1073
441 5278 1983 -344 552 7953 3309 -1081
442 5303 1995 -349 553 7976 3322 -1089
443 5329 2006 -355 554 7999 3334 -1097
444 5354 2017 -360 555 8022 3347 -1105
445 5380 2028 -365 556 8045 3359 -1113
446 5405 2040 -371 557 8067 3372 -1121
447 5430 2051 -376 558 8090 3385 -1130
448 5456 2062 -382 559 8113 3398 -1138
449 5481 2074 -387 560 8136 3410 -1146
450 5506 2085 -393 561 8158 3423 -1154
451 5532 2097 -398 562 8181 3436 -1162
452 5557 2108 -404 563 8204 3448 -1170
107
453 5582 2119 -409 564 8226 3461 -1178
454 5607 2131 -415 565 8249 3474 -1187
455 5633 2142 -421 566 8271 3487 -1195
456 5658 2154 -426 567 8294 3499 -1203
457 5683 2165 -432 568 8317 3512 -1212
458 5708 2177 -438 569 8339 3525 -1220
459 5733 2188 -443 570 8362 3538 -1228
460 5758 2200 -449 571 8384 3551 -1237
461 5783 2211 -455 572 8407 3564 -1245
462 5808 2223 -461 573 8429 3576 -1253
463 5833 2234 -466 574 8452 3589 -1262
464 5858 2246 -472 575 8474 3602 -1270
465 5883 2257 -478 576 8496 3615 -1279
466 5907 2269 -484 577 8519 3628 -1287
467 5932 2280 -490 578 8541 3641 -1296
468 5957 2292 -496 579 8564 3654 -1304
469 5982 2304 -502 580 8586 3667 -1313
470 6007 2315 -508 581 8608 3680 -1322
471 6031 2327 -514 582 8631 3693 -1330
472 6056 2339 -520 583 8653 3706 -1339
473 6081 2350 -526 584 8675 3719 -1348
474 6105 2362 -532 585 8697 3732 -1356
475 6130 2373 -538 586 8720 3745 -1365
476 6155 2385 -544 587 8742 3758 -1374
477 6179 2397 -551 588 8764 3771 -1382
478 6204 2409 -557 589 8786 3784 -1391
479 6228 2420 -563 590 8808 3797 -1400
480 6253 2432 -569 591 8831 3810 -1409
481 6277 2444 -575 592 8853 3823 -1418
482 6301 2456 -582 593 8875 3836 -1426
483 6326 2467 -588 594 8897 3849 -1435
484 6350 2479 -594 595 8919 3863 -1444
485 6375 2491 -601 596 8941 3876 -1453
486 6399 2503 -607 597 8963 3889 -1462
487 6423 2515 -614 598 8985 3902 -1471
488 6448 2526 -620 599 9007 3915 -1480
489 6472 2538 -626 600 9029 3928 -1489
490 6496 2550 -633 601 9051 3942 -1498
491 6520 2562 -639 602 9073 3955 -1507
492 6544 2574 -646 603 9095 3968 -1516
108
493 6569 2586 -653 604 9117 3981 -1525
494 6593 2598 -659 605 9139 3994 -1535
495 6617 2610 -666 606 9161 4008 -1544
496 6641 2621 -672 607 9183 4021 -1553
497 6665 2633 -679 608 9205 4034 -1562
498 6689 2645 -686 609 9226 4048 -1571
499 6713 2657 -692 610 9248 4061 -1581
500 6737 2669 -699 611 9270 4074 -1590
501 6761 2681 -706 612 9292 4088 -1599
502 6785 2693 -713 613 9314 4101 -1608
503 6809 2705 -719 614 9335 4114 -1618
504 6833 2717 -726 615 9357 4128 -1627
505 6856 2729 -733 616 9379 4141 -1636
506 6880 2741 -740 617 9401 4154 -1646
507 6904 2754 -747 618 9422 4168 -1655
508 6928 2766 -754 619 9444 4181 -1665
509 6952 2778 -761 620 9466 4195 -1674
510 6975 2790 -768 621 9487 4208 -1684
511 6999 2802 -775 622 9509 4222 -1693
512 7023 2814 -782 623 9531 4235 -1703
513 7047 2826 -789 62315 9534 4237 -1704
109
Appendix B
Table B1 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(29815-39215K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 347 1233 382 -046
299 022 006 000 348 1258 390 -048
300 049 014 -001 349 1283 398 -049
301 075 022 -001 350 1307 406 -051
302 101 029 -001 351 1332 415 -053
303 127 037 -002 352 1356 423 -054
304 153 044 -002 353 1381 431 -056
305 179 052 -003 354 1405 440 -058
306 205 059 -003 355 1430 448 -060
307 230 067 -004 356 1455 456 -061
308 256 075 -004 357 1479 465 -063
309 282 082 -005 358 1504 473 -065
310 308 090 -005 359 1528 482 -067
311 333 098 -006 360 1553 490 -069
312 359 105 -007 361 1577 498 -071
313 384 113 -007 362 1602 507 -073
314 410 121 -008 363 1626 515 -075
315 435 128 -009 364 1651 524 -077
316 461 136 -010 365 1675 533 -079
317 486 144 -010 366 1700 541 -081
318 511 151 -011 367 1724 550 -083
319 537 159 -012 368 1749 558 -085
320 562 167 -013 369 1773 567 -087
321 587 175 -014 370 1798 576 -089
322 612 182 -015 371 1822 584 -092
323 637 190 -016 372 1847 593 -094
324 663 198 -017 373 1871 602 -096
325 688 206 -018 374 1896 611 -098
326 713 214 -019 375 1920 620 -100
327 738 222 -020 376 1945 628 -103
328 763 229 -021 377 1969 637 -105
329 788 237 -022 378 1994 646 -107
110
330 813 245 -023 379 2018 655 -110
331 838 253 -024 380 2043 664 -112
332 863 261 -025 381 2068 673 -115
333 887 269 -027 382 2092 682 -117
334 912 277 -028 383 2117 691 -120
335 937 285 -029 384 2141 700 -122
336 962 293 -030 385 2166 709 -125
337 987 301 -032 386 2191 718 -127
338 1011 309 -033 387 2215 727 -130
339 1036 317 -034 388 2240 737 -132
340 1061 325 -036 389 2265 746 -135
341 1086 333 -037 390 2289 755 -138
342 1110 341 -039 391 2314 764 -140
343 1135 349 -040 392 2339 774 -143
344 1160 357 -042 39215 2342 775 -144
345 1184 365 -043
Table B2 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(41315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
414 3280 1149 -209 520 5608 2235 -682
415 3302 1158 -212 521 5630 2246 -687
416 3325 1167 -216 522 5651 2257 -693
417 3348 1177 -219 523 5672 2268 -698
418 3370 1186 -223 524 5694 2279 -704
419 3393 1196 -226 525 5715 2290 -710
420 3416 1205 -229 526 5736 2302 -716
421 3438 1215 -233 527 5757 2313 -721
422 3461 1224 -236 528 5779 2324 -727
423 3483 1234 -240 529 5800 2335 -733
424 3506 1243 -243 530 5821 2347 -739
425 3529 1253 -247 531 5842 2358 -745
426 3551 1263 -250 532 5864 2369 -750
427 3574 1272 -254 533 5885 2380 -756
428 3596 1282 -257 534 5906 2392 -762
429 3619 1291 -261 535 5927 2403 -768
111
430 3641 1301 -265 536 5948 2414 -774
431 3663 1311 -268 537 5970 2426 -780
432 3686 1320 -272 538 5991 2437 -786
433 3708 1330 -276 539 6012 2449 -792
434 3731 1340 -279 540 6033 2460 -798
435 3753 1350 -283 541 6054 2471 -804
436 3775 1359 -287 542 6075 2483 -810
437 3798 1369 -291 543 6096 2494 -816
438 3820 1379 -294 544 6118 2506 -822
439 3842 1389 -298 545 6139 2517 -828
440 3865 1398 -302 546 6160 2529 -835
441 3887 1408 -306 547 6181 2540 -841
442 3909 1418 -310 548 6202 2552 -847
443 3932 1428 -314 549 6223 2563 -853
444 3954 1438 -318 550 6244 2575 -859
445 3976 1448 -322 551 6265 2586 -866
446 3998 1458 -326 552 6286 2598 -872
447 4021 1468 -330 553 6307 2610 -878
448 4043 1477 -334 554 6328 2621 -884
449 4065 1487 -338 555 6349 2633 -891
450 4087 1497 -342 556 6370 2645 -897
451 4109 1507 -346 557 6391 2656 -904
452 4131 1517 -350 558 6412 2668 -910
453 4154 1527 -354 559 6433 2680 -916
454 4176 1537 -358 560 6454 2691 -923
455 4198 1547 -363 561 6475 2703 -929
456 4220 1557 -367 562 6496 2715 -936
457 4242 1568 -371 563 6517 2727 -942
458 4264 1578 -375 564 6538 2738 -949
459 4286 1588 -380 565 6559 2750 -955
460 4308 1598 -384 566 6580 2762 -962
461 4330 1608 -388 567 6600 2774 -969
462 4352 1618 -393 568 6621 2786 -975
463 4374 1628 -397 569 6642 2798 -982
464 4396 1639 -401 570 6663 2810 -988
465 4418 1649 -406 571 6684 2821 -995
466 4440 1659 -410 572 6705 2833 -1002
467 4462 1669 -415 573 6726 2845 -1009
468 4484 1680 -419 574 6747 2857 -1015
469 4506 1690 -424 575 6767 2869 -1022
112
470 4528 1700 -428 576 6788 2881 -1029
471 4550 1710 -433 577 6809 2893 -1036
472 4572 1721 -437 578 6830 2905 -1042
473 4593 1731 -442 579 6851 2917 -1049
474 4615 1741 -446 580 6871 2929 -1056
475 4637 1752 -451 581 6892 2941 -1063
476 4659 1762 -456 582 6913 2953 -1070
477 4681 1773 -460 583 6934 2966 -1077
478 4703 1783 -465 584 6954 2978 -1084
479 4724 1793 -470 585 6975 2990 -1091
480 4746 1804 -474 586 6996 3002 -1098
481 4768 1814 -479 587 7017 3014 -1105
482 4790 1825 -484 588 7037 3026 -1112
483 4812 1835 -489 589 7058 3038 -1119
484 4833 1846 -494 590 7079 3051 -1126
485 4855 1856 -498 591 7100 3063 -1133
486 4877 1867 -503 592 7120 3075 -1140
487 4898 1877 -508 593 7141 3087 -1147
488 4920 1888 -513 594 7162 3100 -1154
489 4942 1899 -518 595 7182 3112 -1162
490 4963 1909 -523 596 7203 3124 -1169
491 4985 1920 -528 597 7224 3137 -1176
492 5007 1930 -533 598 7244 3149 -1183
493 5028 1941 -538 599 7265 3161 -1190
494 5050 1952 -543 600 7285 3174 -1198
495 5072 1962 -548 601 7306 3186 -1205
496 5093 1973 -553 602 7327 3198 -1212
497 5115 1984 -558 603 7347 3211 -1220
498 5136 1995 -563 604 7368 3223 -1227
499 5158 2005 -568 605 7389 3236 -1234
500 5180 2016 -574 606 7409 3248 -1242
501 5201 2027 -579 607 7430 3261 -1249
502 5223 2038 -584 608 7450 3273 -1257
503 5244 2049 -589 609 7471 3286 -1264
504 5266 2059 -595 610 7491 3298 -1272
505 5287 2070 -600 611 7512 3311 -1279
506 5309 2081 -605 612 7532 3323 -1287
507 5330 2092 -610 613 7553 3336 -1294
508 5352 2103 -616 614 7573 3348 -1302
509 5373 2114 -621 615 7594 3361 -1309
113
510 5394 2125 -627 616 7615 3374 -1317
511 5416 2136 -632 617 7635 3386 -1325
512 5437 2147 -637 618 7656 3399 -1332
513 5459 2158 -643 619 7676 3412 -1340
514 5480 2169 -648 620 7696 3424 -1348
515 5502 2180 -654 621 7717 3437 -1355
516 5523 2191 -659 622 7737 3450 -1363
517 5544 2202 -665 623 7758 3462 -1371
518 5566 2213 -670 62315 7761 3464 -1372
114
Appendix C
Table C1 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in solid
state (29815-36415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 333 1937 611 -034
299 048 014 000 334 1992 629 -036
300 104 031 000 335 2047 647 -038
301 160 048 000 336 2102 666 -040
302 216 065 000 337 2156 684 -042
303 272 082 -001 338 2211 703 -045
304 329 099 -001 339 2266 721 -047
305 385 116 -001 340 2321 740 -049
306 441 133 -002 341 2375 758 -052
307 496 150 -002 342 2430 777 -054
308 552 167 -003 343 2485 796 -056
309 608 185 -003 344 2539 815 -059
310 664 202 -004 345 2594 833 -062
311 720 219 -005 346 2648 852 -064
312 776 236 -006 347 2703 871 -067
313 831 254 -006 348 2757 890 -070
314 887 271 -007 349 2812 909 -072
315 942 289 -008 350 2866 928 -075
316 998 306 -009 351 2921 947 -078
317 1054 324 -010 352 2975 966 -081
318 1109 341 -011 353 3029 985 -084
319 1164 359 -012 354 3084 1004 -087
320 1220 377 -014 355 3138 1024 -090
321 1275 395 -015 356 3192 1043 -094
322 1331 412 -016 357 3246 1062 -097
323 1386 430 -018 358 3300 1082 -100
324 1441 448 -019 359 3355 1101 -103
325 1496 466 -020 360 3409 1120 -107
326 1552 484 -022 361 3463 1140 -110
327 1607 502 -024 362 3517 1159 -114
328 1662 520 -025 363 3571 1179 -117
329 1717 538 -027 364 3625 1199 -121
115
330 1772 556 -029 36415 3633 1202 -121
331 1827 574 -030
332 1882 593 -032
Table C2 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in liquid
state (42115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
42115 7428 2673 -455 523 11788 4725 -1440
422 7468 2690 -461 524 11827 4745 -1452
423 7515 2710 -468 525 11866 4766 -1464
424 7562 2730 -476 526 11904 4786 -1476
425 7608 2750 -484 527 11943 4807 -1488
426 7655 2770 -491 528 11982 4827 -1500
427 7702 2790 -499 529 12021 4847 -1512
428 7748 2810 -507 530 12059 4868 -1524
429 7795 2830 -514 531 12098 4888 -1536
430 7841 2849 -522 532 12137 4909 -1548
431 7887 2869 -530 533 12175 4929 -1560
432 7933 2889 -538 534 12213 4950 -1572
433 7979 2909 -546 535 12252 4970 -1584
434 8025 2929 -554 536 12290 4991 -1597
435 8071 2949 -562 537 12328 5011 -1609
436 8117 2969 -570 538 12366 5032 -1621
437 8163 2989 -578 539 12404 5052 -1634
438 8208 3009 -586 540 12442 5073 -1646
439 8254 3029 -595 541 12480 5093 -1659
440 8299 3049 -603 542 12518 5114 -1671
441 8345 3069 -611 543 12556 5134 -1684
442 8390 3089 -620 544 12594 5155 -1696
443 8435 3109 -628 545 12632 5175 -1709
444 8480 3129 -636 546 12669 5196 -1721
445 8525 3149 -645 547 12707 5217 -1734
446 8570 3169 -654 548 12745 5237 -1747
116
447 8615 3189 -662 549 12782 5258 -1760
448 8659 3209 -671 550 12820 5278 -1772
449 8704 3229 -679 551 12857 5299 -1785
450 8748 3249 -688 552 12894 5319 -1798
451 8793 3269 -697 553 12932 5340 -1811
452 8837 3289 -706 554 12969 5361 -1824
453 8881 3309 -715 555 13006 5381 -1837
454 8926 3329 -724 556 13043 5402 -1850
455 8970 3349 -732 557 13080 5422 -1863
456 9014 3369 -741 558 13117 5443 -1876
457 9058 3389 -750 559 13154 5464 -1889
458 9102 3409 -760 560 13191 5484 -1902
459 9145 3429 -769 561 13228 5505 -1916
460 9189 3449 -778 562 13264 5526 -1929
461 9233 3469 -787 563 13301 5546 -1942
462 9276 3489 -796 564 13338 5567 -1956
463 9319 3509 -806 565 13374 5588 -1969
464 9363 3529 -815 566 13411 5608 -1982
465 9406 3549 -824 567 13447 5629 -1996
466 9449 3570 -834 568 13484 5650 -2009
467 9492 3590 -843 569 13520 5670 -2023
468 9535 3610 -853 570 13557 5691 -2036
469 9578 3630 -862 571 13593 5712 -2050
470 9621 3650 -872 572 13629 5732 -2063
471 9664 3670 -882 573 13665 5753 -2077
472 9707 3690 -891 574 13701 5774 -2091
473 9749 3710 -901 575 13737 5795 -2104
474 9792 3731 -911 576 13773 5815 -2118
475 9834 3751 -921 577 13809 5836 -2132
476 9877 3771 -930 578 13845 5857 -2146
477 9919 3791 -940 579 13881 5877 -2160
478 9961 3811 -950 580 13917 5898 -2174
479 10004 3831 -960 581 13953 5919 -2188
480 10046 3852 -970 582 13988 5940 -2202
481 10088 3872 -980 583 14024 5960 -2216
482 10130 3892 -990 584 14060 5981 -2230
483 10171 3912 -1001 585 14095 6002 -2244
484 10213 3932 -1011 586 14131 6023 -2258
485 10255 3953 -1021 587 14166 6044 -2272
486 10297 3973 -1031 588 14201 6064 -2286
117
487 10338 3993 -1042 589 14237 6085 -2300
488 10380 4013 -1052 590 14272 6106 -2315
489 10421 4034 -1062 591 14307 6127 -2329
490 10462 4054 -1073 592 14342 6148 -2343
491 10504 4074 -1083 593 14378 6168 -2358
492 10545 4094 -1094 594 14413 6189 -2372
493 10586 4114 -1104 595 14448 6210 -2386
494 10627 4135 -1115 596 14483 6231 -2401
495 10668 4155 -1126 597 14518 6252 -2415
496 10709 4175 -1136 598 14552 6273 -2430
497 10750 4196 -1147 599 14587 6293 -2444
498 10791 4216 -1158 600 14622 6314 -2459
499 10831 4236 -1169 601 14657 6335 -2474
500 10872 4256 -1179 602 14692 6356 -2488
501 10912 4277 -1190 603 14726 6377 -2503
502 10953 4297 -1201 604 14761 6398 -2518
503 10993 4317 -1212 605 14795 6419 -2533
504 11034 4338 -1223 606 14830 6439 -2547
505 11074 4358 -1234 607 14864 6460 -2562
506 11114 4378 -1245 608 14899 6481 -2577
507 11154 4399 -1257 609 14933 6502 -2592
508 11194 4419 -1268 610 14967 6523 -2607
509 11234 4439 -1279 611 15002 6544 -2622
510 11274 4460 -1290 612 15036 6565 -2637
511 11314 4480 -1302 613 15070 6586 -2652
512 11354 4500 -1313 614 15104 6607 -2667
513 11394 4521 -1324 615 15138 6628 -2682
514 11433 4541 -1336 616 15172 6649 -2697
515 11473 4562 -1347 617 15206 6670 -2713
516 11513 4582 -1359 618 15240 6691 -2728
517 11552 4602 -1370 619 15274 6712 -2743
518 11591 4623 -1382 620 15308 6733 -2758
519 11631 4643 -1393 621 15342 6754 -2774
520 11670 4664 -1405 622 15375 6774 -2789
521 11709 4684 -1417 623 15409 6795 -2804
522 11748 4704 -1428 62315 15414 6799 -2807
118
Appendix D
Table D1 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in solid state
(29815-36315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
299 021 006 000 333 867 277 -012
300 047 014 000 334 891 285 -012
301 072 022 000 335 916 293 -013
302 097 029 000 336 940 302 -014
303 122 037 000 337 964 310 -015
304 147 045 000 338 989 318 -016
305 172 053 000 339 1013 327 -017
306 197 060 000 340 1037 335 -018
307 223 068 000 341 1061 343 -019
308 248 076 000 342 1085 352 -019
309 273 084 000 343 1109 360 -020
310 298 092 -001 344 1134 369 -021
311 323 099 -001 345 1158 377 -022
312 348 107 -001 346 1182 385 -024
313 373 115 -001 347 1206 394 -025
314 398 123 -002 348 1230 402 -026
315 423 131 -002 349 1254 411 -027
316 447 139 -002 350 1277 419 -028
317 472 147 -003 351 1301 428 -029
318 497 155 -003 352 1325 436 -030
319 522 163 -003 353 1349 445 -032
320 547 171 -004 354 1373 453 -033
321 572 179 -004 355 1396 462 -034
322 596 187 -005 356 1420 470 -035
323 621 195 -005 357 1444 479 -037
324 646 203 -006 358 1467 487 -038
325 670 211 -006 359 1491 496 -039
326 695 220 -007 360 1514 504 -041
327 720 228 -008 361 1538 513 -042
328 744 236 -008 362 1561 522 -043
329 769 244 -009 363 1584 530 -045
330 793 252 -010 36315 1588 532 -045
119
331 818 260 -010
Table D2 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in liquid
state (38115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
38115 2281 765 -104 503 5639 2242 -594
382 2307 775 -106 504 5664 2255 -600
383 2338 787 -109 505 5689 2267 -606
384 2369 798 -111 506 5713 2280 -611
385 2399 810 -113 507 5738 2292 -617
386 2430 822 -116 508 5763 2305 -623
387 2460 834 -118 509 5787 2317 -629
388 2491 846 -121 510 5812 2330 -634
389 2521 857 -123 511 5836 2342 -640
390 2551 869 -126 512 5861 2355 -646
391 2582 881 -128 513 5885 2367 -652
392 2612 893 -131 514 5910 2380 -658
393 2642 905 -134 515 5934 2392 -664
394 2672 917 -136 516 5959 2405 -670
395 2702 928 -139 517 5983 2417 -676
396 2732 940 -142 518 6007 2430 -682
397 2762 952 -144 519 6032 2443 -688
398 2792 964 -147 520 6056 2455 -694
399 2821 976 -150 521 6080 2468 -700
400 2851 988 -153 522 6104 2480 -706
401 2881 999 -156 523 6128 2493 -712
402 2910 1011 -159 524 6152 2506 -718
403 2940 1023 -162 525 6176 2518 -724
404 2969 1035 -164 526 6200 2531 -731
405 2999 1047 -167 527 6224 2544 -737
406 3028 1059 -170 528 6248 2556 -743
407 3057 1071 -174 529 6272 2569 -749
408 3087 1083 -177 530 6296 2581 -756
120
409 3116 1095 -180 531 6320 2594 -762
410 3145 1107 -183 532 6344 2607 -768
411 3174 1119 -186 533 6368 2619 -775
412 3203 1130 -189 534 6391 2632 -781
413 3232 1142 -192 535 6415 2645 -787
414 3261 1154 -196 536 6439 2657 -794
415 3290 1166 -199 537 6462 2670 -800
416 3319 1178 -202 538 6486 2683 -807
417 3347 1190 -206 539 6510 2696 -813
418 3376 1202 -209 540 6533 2708 -820
419 3405 1214 -212 541 6557 2721 -826
420 3433 1226 -216 542 6580 2734 -833
421 3462 1238 -219 543 6604 2746 -839
422 3490 1250 -223 544 6627 2759 -846
423 3519 1262 -226 545 6650 2772 -853
424 3547 1274 -230 546 6674 2785 -859
425 3575 1286 -233 547 6697 2797 -866
426 3604 1298 -237 548 6720 2810 -873
427 3632 1310 -240 549 6744 2823 -879
428 3660 1322 -244 550 6767 2836 -886
429 3688 1334 -248 551 6790 2848 -893
430 3716 1346 -251 552 6813 2861 -900
431 3744 1358 -255 553 6836 2874 -907
432 3772 1371 -259 554 6860 2887 -913
433 3800 1383 -263 555 6883 2900 -920
434 3828 1395 -267 556 6906 2912 -927
435 3856 1407 -270 557 6929 2925 -934
436 3883 1419 -274 558 6952 2938 -941
437 3911 1431 -278 559 6975 2951 -948
438 3939 1443 -282 560 6998 2964 -955
439 3966 1455 -286 561 7020 2976 -962
440 3994 1467 -290 562 7043 2989 -969
441 4021 1479 -294 563 7066 3002 -976
442 4049 1491 -298 564 7089 3015 -983
443 4076 1504 -302 565 7112 3028 -990
444 4103 1516 -306 566 7134 3041 -997
445 4131 1528 -310 567 7157 3054 -1005
446 4158 1540 -314 568 7180 3066 -1012
447 4185 1552 -319 569 7203 3079 -1019
448 4212 1564 -323 570 7225 3092 -1026
121
449 4240 1576 -327 571 7248 3105 -1033
450 4267 1589 -331 572 7270 3118 -1041
451 4294 1601 -336 573 7293 3131 -1048
452 4321 1613 -340 574 7315 3144 -1055
453 4347 1625 -344 575 7338 3157 -1063
454 4374 1637 -349 576 7360 3170 -1070
455 4401 1650 -353 577 7383 3183 -1077
456 4428 1662 -357 578 7405 3196 -1085
457 4455 1674 -362 579 7428 3208 -1092
458 4481 1686 -366 580 7450 3221 -1100
459 4508 1698 -371 581 7472 3234 -1107
460 4535 1711 -375 582 7494 3247 -1114
461 4561 1723 -380 583 7517 3260 -1122
462 4588 1735 -384 584 7539 3273 -1129
463 4614 1747 -389 585 7561 3286 -1137
464 4641 1760 -394 586 7583 3299 -1145
465 4667 1772 -398 587 7605 3312 -1152
466 4693 1784 -403 588 7628 3325 -1160
467 4720 1796 -408 589 7650 3338 -1167
468 4746 1809 -412 590 7672 3351 -1175
469 4772 1821 -417 591 7694 3364 -1183
470 4798 1833 -422 592 7716 3377 -1191
471 4825 1846 -427 593 7738 3390 -1198
472 4851 1858 -432 594 7760 3403 -1206
473 4877 1870 -437 595 7782 3416 -1214
474 4903 1882 -441 596 7804 3429 -1222
475 4929 1895 -446 597 7825 3442 -1229
476 4955 1907 -451 598 7847 3455 -1237
477 4980 1919 -456 599 7869 3469 -1245
478 5006 1932 -461 600 7891 3482 -1253
479 5032 1944 -466 601 7913 3495 -1261
480 5058 1956 -471 602 7934 3508 -1269
481 5083 1969 -476 603 7956 3521 -1277
482 5109 1981 -481 604 7978 3534 -1285
483 5135 1994 -487 605 8000 3547 -1293
484 5160 2006 -492 606 8021 3560 -1301
485 5186 2018 -497 607 8043 3573 -1309
486 5211 2031 -502 608 8064 3586 -1317
487 5237 2043 -507 609 8086 3599 -1325
488 5262 2055 -513 610 8107 3613 -1333
122
489 5288 2068 -518 611 8129 3626 -1341
490 5313 2080 -523 612 8150 3639 -1349
491 5338 2093 -528 613 8172 3652 -1357
492 5364 2105 -534 614 8193 3665 -1366
493 5389 2117 -539 615 8215 3678 -1374
494 5414 2130 -545 616 8236 3692 -1382
495 5439 2142 -550 617 8258 3705 -1390
496 5464 2155 -555 618 8279 3718 -1398
497 5489 2167 -561 619 8300 3731 -1407
498 5514 2180 -566 620 8321 3744 -1415
499 5539 2192 -572 621 8343 3757 -1423
500 5564 2205 -578 622 8364 3771 -1432
501 5589 2217 -583 623 8385 3784 -1441
502 5614 2230 -589 62315 8388 3786 -1443
123
Appendix E
Table E1 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in solid state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 913 287 -014
299 025 007 000 331 941 296 -015
300 054 016 000 332 970 306 -016
301 083 025 000 333 998 315 -017
302 112 034 000 334 1026 324 -018
303 141 042 000 335 1054 334 -019
304 170 051 000 336 1081 343 -020
305 199 060 -001 337 1109 353 -021
306 228 069 -001 338 1137 362 -022
307 257 078 -001 339 1165 371 -024
308 286 087 -001 340 1193 381 -025
309 315 096 -002 341 1221 390 -026
310 343 105 -002 342 1248 400 -027
311 372 113 -002 343 1276 409 -028
312 401 122 -003 344 1304 419 -030
313 430 131 -003 345 1331 428 -031
314 458 140 -003 346 1359 438 -032
315 487 149 -004 347 1386 447 -034
316 516 159 -004 348 1414 457 -035
317 544 168 -005 349 1441 466 -036
318 573 177 -006 350 1468 476 -038
319 602 186 -006 351 1496 486 -039
320 630 195 -007 352 1523 495 -041
321 659 204 -007 353 1550 505 -042
322 687 213 -008 354 1577 514 -044
323 715 222 -009 355 1605 524 -046
324 744 232 -009 356 1632 534 -047
325 772 241 -010 357 1659 543 -049
326 800 250 -011 358 1686 553 -050
327 829 259 -012 359 1713 563 -052
328 857 269 -013 35915 1717 564 -052
329 885 278 -013
124
Table E2 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in liquid state (376-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2323 777 -094 500 5525 2173 -590
376 2347 786 -096 501 5548 2184 -595
377 2375 797 -098 502 5572 2196 -601
378 2403 808 -101 503 5595 2208 -606
379 2431 818 -103 504 5619 2220 -612
380 2459 829 -106 505 5642 2232 -618
381 2487 839 -108 506 5665 2243 -623
382 2515 850 -111 507 5689 2255 -629
383 2542 861 -113 508 5712 2267 -635
384 2570 871 -116 509 5735 2279 -640
385 2598 882 -118 510 5759 2291 -646
386 2626 893 -121 511 5782 2303 -652
387 2653 903 -123 512 5805 2315 -658
388 2681 914 -126 513 5828 2326 -664
389 2708 925 -129 514 5852 2338 -669
390 2736 935 -132 515 5875 2350 -675
391 2763 946 -134 516 5898 2362 -681
392 2791 957 -137 517 5921 2374 -687
393 2818 968 -140 518 5944 2386 -693
394 2845 978 -143 519 5967 2398 -699
395 2873 989 -146 520 5990 2410 -705
396 2900 1000 -148 521 6013 2422 -711
397 2927 1011 -151 522 6036 2434 -717
398 2954 1022 -154 523 6059 2446 -723
399 2981 1032 -157 524 6082 2458 -729
400 3008 1043 -160 525 6105 2470 -735
401 3035 1054 -163 526 6128 2482 -741
402 3062 1065 -166 527 6151 2494 -747
403 3089 1076 -169 528 6173 2506 -754
404 3116 1086 -172 529 6196 2518 -760
405 3143 1097 -176 530 6219 2530 -766
125
406 3170 1108 -179 531 6242 2542 -772
407 3197 1119 -182 532 6265 2554 -778
408 3223 1130 -185 533 6287 2566 -785
409 3250 1141 -188 534 6310 2578 -791
410 3277 1152 -192 535 6333 2591 -797
411 3303 1163 -195 536 6355 2603 -804
412 3330 1174 -198 537 6378 2615 -810
413 3356 1185 -202 538 6400 2627 -816
414 3383 1195 -205 539 6423 2639 -823
415 3409 1206 -208 540 6445 2651 -829
416 3436 1217 -212 541 6468 2663 -836
417 3462 1228 -215 542 6490 2676 -842
418 3488 1239 -219 543 6513 2688 -849
419 3515 1250 -222 544 6535 2700 -855
420 3541 1261 -226 545 6558 2712 -862
421 3567 1272 -229 546 6580 2724 -868
422 3593 1283 -233 547 6602 2737 -875
423 3619 1294 -236 548 6625 2749 -882
424 3645 1305 -240 549 6647 2761 -888
425 3671 1317 -244 550 6669 2773 -895
426 3697 1328 -247 551 6692 2786 -902
427 3723 1339 -251 552 6714 2798 -908
428 3749 1350 -255 553 6736 2810 -915
429 3775 1361 -259 554 6758 2822 -922
430 3801 1372 -262 555 6780 2835 -929
431 3827 1383 -266 556 6803 2847 -935
432 3852 1394 -270 557 6825 2859 -942
433 3878 1405 -274 558 6847 2872 -949
434 3904 1416 -278 559 6869 2884 -956
435 3929 1428 -282 560 6891 2896 -963
436 3955 1439 -286 561 6913 2909 -970
437 3981 1450 -290 562 6935 2921 -977
438 4006 1461 -294 563 6957 2933 -983
439 4032 1472 -298 564 6979 2946 -990
440 4057 1483 -302 565 7001 2958 -997
441 4083 1495 -306 566 7023 2971 -1004
442 4108 1506 -310 567 7045 2983 -1011
443 4133 1517 -314 568 7067 2995 -1019
444 4159 1528 -318 569 7089 3008 -1026
445 4184 1540 -322 570 7110 3020 -1033
126
446 4209 1551 -327 571 7132 3033 -1040
447 4234 1562 -331 572 7154 3045 -1047
448 4260 1573 -335 573 7176 3058 -1054
449 4285 1585 -339 574 7198 3070 -1061
450 4310 1596 -344 575 7219 3083 -1069
451 4335 1607 -348 576 7241 3095 -1076
452 4360 1618 -352 577 7263 3108 -1083
453 4385 1630 -357 578 7284 3120 -1090
454 4410 1641 -361 579 7306 3133 -1098
455 4435 1652 -365 580 7328 3145 -1105
456 4460 1664 -370 581 7349 3158 -1112
457 4485 1675 -374 582 7371 3170 -1120
458 4510 1687 -379 583 7393 3183 -1127
459 4534 1698 -383 584 7414 3195 -1134
460 4559 1709 -388 585 7436 3208 -1142
461 4584 1721 -393 586 7457 3221 -1149
462 4609 1732 -397 587 7479 3233 -1157
463 4633 1743 -402 588 7500 3246 -1164
464 4658 1755 -406 589 7522 3258 -1172
465 4683 1766 -411 590 7543 3271 -1179
466 4707 1778 -416 591 7564 3284 -1187
467 4732 1789 -420 592 7586 3296 -1194
468 4756 1801 -425 593 7607 3309 -1202
469 4781 1812 -430 594 7628 3322 -1210
470 4805 1824 -435 595 7650 3334 -1217
471 4830 1835 -440 596 7671 3347 -1225
472 4854 1847 -444 597 7692 3360 -1233
473 4878 1858 -449 598 7714 3373 -1240
474 4903 1870 -454 599 7735 3385 -1248
475 4927 1881 -459 600 7756 3398 -1256
476 4951 1893 -464 601 7777 3411 -1264
477 4975 1904 -469 602 7799 3423 -1271
478 5000 1916 -474 603 7820 3436 -1279
479 5024 1927 -479 604 7841 3449 -1287
480 5048 1939 -484 605 7862 3462 -1295
481 5072 1951 -489 606 7883 3475 -1303
482 5096 1962 -494 607 7904 3487 -1311
483 5120 1974 -499 608 7925 3500 -1318
484 5144 1985 -504 609 7946 3513 -1326
485 5168 1997 -510 610 7967 3526 -1334
127
486 5192 2009 -515 611 7988 3539 -1342
487 5216 2020 -520 612 8009 3551 -1350
488 5240 2032 -525 613 8030 3564 -1358
489 5264 2044 -530 614 8051 3577 -1366
490 5288 2055 -536 615 8072 3590 -1374
491 5312 2067 -541 616 8093 3603 -1383
492 5335 2079 -546 617 8114 3616 -1391
493 5359 2090 -552 618 8135 3629 -1399
494 5383 2102 -557 619 8156 3642 -1407
495 5407 2114 -562 620 8177 3655 -1415
496 5430 2126 -568 621 8198 3667 -1423
497 5454 2137 -573 622 8219 3680 -1431
498 5478 2149 -579 623 8239 3693 -1440
499 5501 2161 -584 62315 8242 3695 -1441
128
Appendix F
Table F1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in solid
state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 1063 334 -017
299 029 009 000 331 1096 345 -018
300 063 019 000 332 1128 356 -019
301 097 029 000 333 1161 366 -020
302 131 039 000 334 1193 377 -021
303 165 050 000 335 1225 388 -022
304 199 060 -001 336 1258 399 -024
305 233 070 -001 337 1290 410 -025
306 267 081 -001 338 1322 421 -026
307 300 091 -001 339 1355 432 -028
308 334 101 -002 340 1387 443 -029
309 368 112 -002 341 1419 454 -030
310 401 122 -002 342 1451 464 -032
311 435 133 -003 343 1483 475 -033
312 468 143 -003 344 1515 486 -035
313 502 153 -004 345 1547 497 -036
314 535 164 -004 346 1578 508 -038
315 569 174 -005 347 1610 519 -039
316 602 185 -005 348 1642 531 -041
317 635 196 -006 349 1674 542 -043
318 668 206 -006 350 1705 553 -044
319 702 217 -007 351 1737 564 -046
320 735 227 -008 352 1769 575 -048
321 768 238 -009 353 1800 586 -049
322 801 248 -009 354 1832 597 -051
323 834 259 -010 355 1863 608 -053
324 867 270 -011 356 1894 619 -055
325 900 280 -012 357 1926 631 -057
326 932 291 -013 358 1957 642 -059
327 965 302 -014 359 1988 653 -061
328 998 313 -015 35915 1993 655 -061
329 1030 323 -016
129
Table F2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in liquid
state (37515-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2691 926 -083 500 6111 2416 -640
376 2717 936 -085 501 6136 2428 -646
377 2747 948 -088 502 6161 2440 -652
378 2778 959 -091 503 6185 2453 -658
379 2808 971 -094 504 6210 2465 -665
380 2838 982 -096 505 6235 2478 -671
381 2869 994 -099 506 6259 2490 -677
382 2899 1005 -102 507 6284 2502 -683
383 2929 1017 -105 508 6308 2515 -690
384 2959 1028 -108 509 6333 2527 -696
385 2989 1040 -111 510 6357 2540 -702
386 3019 1051 -114 511 6381 2552 -709
387 3049 1063 -117 512 6406 2565 -715
388 3079 1075 -120 513 6430 2577 -721
389 3109 1086 -123 514 6454 2590 -728
390 3138 1098 -126 515 6479 2602 -734
391 3168 1109 -129 516 6503 2615 -741
392 3198 1121 -133 517 6527 2627 -747
393 3227 1132 -136 518 6551 2640 -754
394 3257 1144 -139 519 6575 2652 -760
395 3286 1156 -142 520 6599 2665 -767
396 3316 1167 -146 521 6624 2677 -774
397 3345 1179 -149 522 6648 2690 -780
398 3374 1191 -152 523 6672 2702 -787
399 3403 1202 -156 524 6696 2715 -794
400 3433 1214 -159 525 6719 2727 -800
401 3462 1226 -163 526 6743 2740 -807
402 3491 1237 -166 527 6767 2753 -814
403 3520 1249 -170 528 6791 2765 -821
404 3549 1261 -173 529 6815 2778 -827
405 3578 1272 -177 530 6839 2790 -834
130
406 3606 1284 -180 531 6862 2803 -841
407 3635 1296 -184 532 6886 2815 -848
408 3664 1307 -187 533 6910 2828 -855
409 3693 1319 -191 534 6933 2841 -862
410 3721 1331 -195 535 6957 2853 -869
411 3750 1343 -199 536 6981 2866 -876
412 3778 1354 -202 537 7004 2879 -883
413 3807 1366 -206 538 7028 2891 -890
414 3835 1378 -210 539 7051 2904 -897
415 3864 1390 -214 540 7075 2917 -904
416 3892 1401 -218 541 7098 2929 -911
417 3920 1413 -222 542 7122 2942 -918
418 3948 1425 -226 543 7145 2955 -925
419 3977 1437 -230 544 7168 2967 -932
420 4005 1449 -234 545 7192 2980 -939
421 4033 1460 -238 546 7215 2993 -947
422 4061 1472 -242 547 7238 3005 -954
423 4089 1484 -246 548 7261 3018 -961
424 4117 1496 -250 549 7285 3031 -968
425 4145 1508 -254 550 7308 3044 -976
426 4172 1519 -258 551 7331 3056 -983
427 4200 1531 -262 552 7354 3069 -990
428 4228 1543 -266 553 7377 3082 -998
429 4256 1555 -271 554 7400 3095 -1005
430 4283 1567 -275 555 7423 3107 -1013
431 4311 1579 -279 556 7446 3120 -1020
432 4338 1591 -284 557 7469 3133 -1027
433 4366 1603 -288 558 7492 3146 -1035
434 4393 1614 -292 559 7515 3159 -1042
435 4421 1626 -297 560 7538 3171 -1050
436 4448 1638 -301 561 7561 3184 -1058
437 4475 1650 -306 562 7584 3197 -1065
438 4503 1662 -310 563 7607 3210 -1073
439 4530 1674 -315 564 7629 3223 -1080
440 4557 1686 -319 565 7652 3235 -1088
441 4584 1698 -324 566 7675 3248 -1096
442 4611 1710 -328 567 7697 3261 -1103
443 4638 1722 -333 568 7720 3274 -1111
444 4665 1734 -338 569 7743 3287 -1119
445 4692 1746 -342 570 7765 3300 -1126
131
446 4719 1758 -347 571 7788 3313 -1134
447 4746 1770 -352 572 7811 3326 -1142
448 4773 1782 -356 573 7833 3338 -1150
449 4800 1794 -361 574 7856 3351 -1158
450 4826 1806 -366 575 7878 3364 -1166
451 4853 1818 -371 576 7901 3377 -1173
452 4880 1830 -376 577 7923 3390 -1181
453 4906 1842 -381 578 7945 3403 -1189
454 4933 1854 -386 579 7968 3416 -1197
455 4959 1866 -391 580 7990 3429 -1205
456 4986 1878 -396 581 8012 3442 -1213
457 5012 1890 -401 582 8035 3455 -1221
458 5039 1902 -406 583 8057 3468 -1229
459 5065 1914 -411 584 8079 3481 -1237
460 5091 1926 -416 585 8101 3494 -1245
461 5118 1938 -421 586 8124 3507 -1254
462 5144 1951 -426 587 8146 3520 -1262
463 5170 1963 -431 588 8168 3533 -1270
464 5196 1975 -436 589 8190 3546 -1278
465 5222 1987 -441 590 8212 3559 -1286
466 5248 1999 -447 591 8234 3572 -1294
467 5274 2011 -452 592 8256 3585 -1303
468 5300 2023 -457 593 8278 3598 -1311
469 5326 2035 -463 594 8300 3611 -1319
470 5352 2048 -468 595 8322 3624 -1328
471 5378 2060 -473 596 8344 3637 -1336
472 5404 2072 -479 597 8366 3650 -1344
473 5430 2084 -484 598 8388 3663 -1353
474 5455 2096 -490 599 8410 3676 -1361
475 5481 2108 -495 600 8432 3690 -1369
476 5507 2121 -500 601 8454 3703 -1378
477 5532 2133 -506 602 8475 3716 -1386
478 5558 2145 -512 603 8497 3729 -1395
479 5583 2157 -517 604 8519 3742 -1403
480 5609 2170 -523 605 8541 3755 -1412
481 5634 2182 -528 606 8562 3768 -1420
482 5660 2194 -534 607 8584 3781 -1429
483 5685 2206 -540 608 8606 3795 -1438
484 5710 2219 -545 609 8627 3808 -1446
485 5736 2231 -551 610 8649 3821 -1455
132
486 5761 2243 -557 611 8670 3834 -1464
487 5786 2255 -563 612 8692 3847 -1472
488 5812 2268 -568 613 8713 3860 -1481
489 5837 2280 -574 614 8735 3874 -1490
490 5862 2292 -580 615 8756 3887 -1498
491 5887 2305 -586 616 8778 3900 -1507
492 5912 2317 -592 617 8799 3913 -1516
493 5937 2329 -598 618 8821 3926 -1525
494 5962 2342 -604 619 8842 3940 -1534
495 5987 2354 -610 620 8864 3953 -1542
496 6012 2366 -616 621 8885 3966 -1551
497 6037 2379 -622 622 8906 3979 -1560
498 6062 2391 -628 623 8928 3993 -1569
499 6086 2403 -634 62315 8931 3995 -1570
133
Appendix G
Table G1 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid I state (29815-33715K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 319 578 162 -004
299 024 000 000 320 606 170 -005
300 052 000 000 321 633 179 -005
301 080 007 000 322 660 188 -006
302 108 016 000 323 688 197 -007
303 136 024 000 324 715 205 -007
304 164 032 000 325 742 214 -008
305 192 041 000 326 769 223 -009
306 219 049 000 327 796 232 -009
307 247 058 000 328 823 241 -010
308 275 067 -001 329 851 250 -011
309 303 075 -001 330 878 259 -011
310 330 084 -001 331 905 268 -012
311 358 092 -001 332 932 277 -013
312 386 101 -002 333 959 285 -014
313 413 109 -002 334 985 294 -015
314 441 118 -002 335 1012 303 -016
315 468 127 -003 336 1039 312 -017
316 496 135 -003 337 1066 321 -018
317 523 144 -003 33715 1070 331 -019
318 551 153 -004
Table G2 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid II state (36115-36415K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36115 2433 825 -054
134
362 2454 832 -056
363 2478 841 -059
364 2503 850 -061
36415 2506 851 -062
Table G3 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
liquid state (41115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
41115 3833 1366 -210 518 6604 2649 -772
412 3857 1376 -213 519 6628 2661 -778
413 3885 1387 -217 520 6652 2674 -785
414 3913 1399 -221 521 6675 2686 -792
415 3941 1411 -225 522 6699 2699 -798
416 3969 1422 -229 523 6723 2711 -805
417 3997 1434 -233 524 6747 2723 -812
418 4025 1446 -237 525 6770 2736 -819
419 4053 1457 -241 526 6794 2748 -825
420 4081 1469 -245 527 6818 2761 -832
421 4109 1481 -249 528 6841 2773 -839
422 4137 1493 -253 529 6865 2786 -846
423 4165 1504 -257 530 6888 2798 -853
424 4192 1516 -262 531 6912 2810 -860
425 4220 1528 -266 532 6935 2823 -867
426 4248 1539 -270 533 6959 2835 -873
427 4275 1551 -274 534 6982 2848 -880
428 4303 1563 -279 535 7005 2860 -887
429 4330 1575 -283 536 7029 2873 -894
430 4358 1587 -287 537 7052 2885 -902
431 4385 1598 -292 538 7075 2898 -909
432 4412 1610 -296 539 7098 2910 -916
433 4439 1622 -300 540 7122 2923 -923
434 4467 1634 -305 541 7145 2935 -930
135
435 4494 1646 -309 542 7168 2948 -937
436 4521 1657 -314 543 7191 2960 -944
437 4548 1669 -318 544 7214 2973 -951
438 4575 1681 -323 545 7237 2986 -959
439 4602 1693 -328 546 7260 2998 -966
440 4629 1705 -332 547 7283 3011 -973
441 4656 1716 -337 548 7306 3023 -980
442 4683 1728 -341 549 7329 3036 -988
443 4710 1740 -346 550 7352 3048 -995
444 4736 1752 -351 551 7375 3061 -1003
445 4763 1764 -356 552 7398 3074 -1010
446 4790 1776 -360 553 7420 3086 -1017
447 4816 1788 -365 554 7443 3099 -1025
448 4843 1800 -370 555 7466 3111 -1032
449 4869 1812 -375 556 7489 3124 -1040
450 4896 1823 -380 557 7511 3137 -1047
451 4922 1835 -385 558 7534 3149 -1055
452 4949 1847 -390 559 7557 3162 -1062
453 4975 1859 -395 560 7579 3175 -1070
454 5002 1871 -400 561 7602 3187 -1077
455 5028 1883 -405 562 7625 3200 -1085
456 5054 1895 -410 563 7647 3213 -1093
457 5080 1907 -415 564 7670 3225 -1100
458 5106 1919 -420 565 7692 3238 -1108
459 5132 1931 -425 566 7714 3251 -1116
460 5159 1943 -430 567 7737 3263 -1123
461 5185 1955 -435 568 7759 3276 -1131
462 5211 1967 -440 569 7782 3289 -1139
463 5236 1979 -446 570 7804 3302 -1147
464 5262 1991 -451 571 7826 3314 -1155
465 5288 2003 -456 572 7849 3327 -1162
466 5314 2015 -461 573 7871 3340 -1170
467 5340 2027 -467 574 7893 3352 -1178
468 5366 2039 -472 575 7915 3365 -1186
469 5391 2051 -478 576 7937 3378 -1194
470 5417 2063 -483 577 7960 3391 -1202
471 5442 2075 -488 578 7982 3404 -1210
472 5468 2087 -494 579 8004 3416 -1218
473 5494 2099 -499 580 8026 3429 -1226
474 5519 2111 -505 581 8048 3442 -1234
136
475 5545 2123 -510 582 8070 3455 -1242
476 5570 2135 -516 583 8092 3468 -1250
477 5595 2147 -521 584 8114 3480 -1258
478 5621 2160 -527 585 8136 3493 -1266
479 5646 2172 -533 586 8158 3506 -1274
480 5671 2184 -538 587 8180 3519 -1283
481 5696 2196 -544 588 8201 3532 -1291
482 5722 2208 -550 589 8223 3545 -1299
483 5747 2220 -555 590 8245 3557 -1307
484 5772 2232 -561 591 8267 3570 -1315
485 5797 2244 -567 592 8289 3583 -1324
486 5822 2257 -573 593 8310 3596 -1332
487 5847 2269 -579 594 8332 3609 -1340
488 5872 2281 -585 595 8354 3622 -1349
489 5897 2293 -590 596 8375 3635 -1357
490 5922 2305 -596 597 8397 3648 -1365
491 5947 2317 -602 598 8419 3660 -1374
492 5971 2330 -608 599 8440 3673 -1382
493 5996 2342 -614 600 8462 3686 -1391
494 6021 2354 -620 601 8483 3699 -1399
495 6046 2366 -626 602 8505 3712 -1408
496 6070 2379 -632 603 8526 3725 -1416
497 6095 2391 -638 604 8548 3738 -1425
498 6119 2403 -645 605 8569 3751 -1433
499 6144 2415 -651 606 8591 3764 -1442
500 6169 2427 -657 607 8612 3777 -1451
501 6193 2440 -663 608 8633 3790 -1459
502 6217 2452 -669 609 8655 3803 -1468
503 6242 2464 -675 610 8676 3816 -1476
504 6266 2477 -682 611 8697 3829 -1485
505 6291 2489 -688 612 8719 3842 -1494
506 6315 2501 -694 613 8740 3855 -1503
507 6339 2513 -701 614 8761 3868 -1511
508 6363 2526 -707 615 8782 3881 -1520
509 6388 2538 -713 616 8803 3894 -1529
510 6412 2550 -720 617 8825 3907 -1538
511 6436 2563 -726 618 8846 3920 -1547
512 6460 2575 -733 619 8867 3933 -1555
513 6484 2587 -739 620 8888 3946 -1564
514 6508 2600 -746 621 8909 3959 -1573
137
515 6532 2612 -752 622 8930 3972 -1582
516 6556 2624 -759 623 8951 3985 -1591
517 6580 2637 -765 62315 8954 3987 -1592
138
Appendix H
Table H1 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid I
state (29815-35415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 768 241 -011
299 023 007 000 328 794 249 -011
300 050 015 000 329 820 258 -012
301 077 023 000 330 846 266 -013
302 104 031 000 331 872 275 -014
303 131 039 000 332 898 284 -015
304 158 048 000 333 924 292 -016
305 185 056 -001 334 950 301 -016
306 212 064 -001 335 976 310 -017
307 239 072 -001 336 1002 318 -018
308 265 081 -001 337 1028 327 -019
309 292 089 -001 338 1053 336 -020
310 319 097 -002 339 1079 344 -021
311 345 105 -002 340 1105 353 -022
312 372 114 -002 341 1130 362 -024
313 399 122 -003 342 1156 371 -025
314 425 130 -003 343 1182 379 -026
315 452 139 -004 344 1207 388 -027
316 478 147 -004 345 1233 397 -028
317 505 156 -004 346 1258 406 -029
318 531 164 -005 347 1284 415 -031
319 558 172 -005 348 1309 424 -032
320 584 181 -006 349 1335 433 -033
321 611 189 -007 350 1360 441 -035
322 637 198 -007 351 1385 450 -036
323 663 206 -008 352 1411 459 -037
324 689 215 -008 353 1436 468 -039
325 716 223 -009 354 1461 477 -040
326 742 232 -010 35415 1465 478 -040
139
Table H2 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid 2
state (36215-37315K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36215 2387 777 -046
363 2408 809 -055
364 2432 817 -057
365 2457 826 -060
366 2481 835 -062
367 2506 843 -065
368 2530 852 -067
369 2555 861 -070
370 2579 870 -072
371 2604 879 -075
372 2628 888 -077
373 2653 898 -080
37315 2657 907 -083
Table H3 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in liquid
state (37915-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37915 2966 1025 -100 502 6174 2432 -667
380 2991 1034 -102 503 6198 2444 -674
381 3020 1045 -105 504 6222 2456 -680
382 3048 1056 -108 505 6246 2468 -686
383 3077 1067 -112 506 6270 2480 -692
384 3105 1078 -115 507 6294 2492 -699
385 3134 1089 -118 508 6317 2504 -705
386 3162 1100 -121 509 6341 2516 -711
387 3191 1111 -124 510 6365 2528 -718
140
388 3219 1122 -127 511 6388 2541 -724
389 3247 1133 -130 512 6412 2553 -730
390 3275 1144 -134 513 6436 2565 -737
391 3304 1155 -137 514 6459 2577 -743
392 3332 1166 -140 515 6483 2589 -750
393 3360 1177 -144 516 6506 2601 -756
394 3388 1188 -147 517 6530 2613 -763
395 3416 1199 -150 518 6553 2625 -769
396 3444 1210 -154 519 6577 2638 -776
397 3472 1221 -157 520 6600 2650 -782
398 3500 1232 -161 521 6624 2662 -789
399 3527 1243 -164 522 6647 2674 -796
400 3555 1254 -168 523 6670 2686 -802
401 3583 1265 -171 524 6694 2698 -809
402 3611 1276 -175 525 6717 2711 -816
403 3638 1287 -179 526 6740 2723 -822
404 3666 1299 -182 527 6763 2735 -829
405 3693 1310 -186 528 6786 2747 -836
406 3721 1321 -190 529 6810 2760 -843
407 3748 1332 -193 530 6833 2772 -850
408 3776 1343 -197 531 6856 2784 -856
409 3803 1354 -201 532 6879 2796 -863
410 3830 1366 -205 533 6902 2809 -870
411 3857 1377 -209 534 6925 2821 -877
412 3885 1388 -213 535 6948 2833 -884
413 3912 1399 -216 536 6971 2845 -891
414 3939 1410 -220 537 6994 2858 -898
415 3966 1422 -224 538 7017 2870 -905
416 3993 1433 -228 539 7040 2882 -912
417 4020 1444 -232 540 7063 2895 -919
418 4047 1455 -236 541 7086 2907 -926
419 4074 1467 -240 542 7108 2919 -933
420 4101 1478 -245 543 7131 2932 -940
421 4128 1489 -249 544 7154 2944 -947
422 4154 1500 -253 545 7177 2957 -955
423 4181 1512 -257 546 7199 2969 -962
424 4208 1523 -261 547 7222 2981 -969
425 4234 1534 -265 548 7245 2994 -976
426 4261 1546 -270 549 7267 3006 -984
427 4288 1557 -274 550 7290 3019 -991
141
428 4314 1568 -278 551 7313 3031 -998
429 4341 1580 -282 552 7335 3044 -1005
430 4367 1591 -287 553 7358 3056 -1013
431 4393 1602 -291 554 7380 3068 -1020
432 4420 1614 -296 555 7403 3081 -1028
433 4446 1625 -300 556 7425 3093 -1035
434 4472 1636 -305 557 7448 3106 -1042
435 4499 1648 -309 558 7470 3118 -1050
436 4525 1659 -314 559 7492 3131 -1057
437 4551 1671 -318 560 7515 3143 -1065
438 4577 1682 -323 561 7537 3156 -1072
439 4603 1694 -327 562 7560 3169 -1080
440 4629 1705 -332 563 7582 3181 -1087
441 4655 1716 -336 564 7604 3194 -1095
442 4681 1728 -341 565 7626 3206 -1103
443 4707 1739 -346 566 7649 3219 -1110
444 4733 1751 -351 567 7671 3231 -1118
445 4759 1762 -355 568 7693 3244 -1126
446 4785 1774 -360 569 7715 3257 -1133
447 4810 1785 -365 570 7737 3269 -1141
448 4836 1797 -370 571 7759 3282 -1149
449 4862 1808 -375 572 7782 3294 -1157
450 4888 1820 -379 573 7804 3307 -1164
451 4913 1832 -384 574 7826 3320 -1172
452 4939 1843 -389 575 7848 3332 -1180
453 4964 1855 -394 576 7870 3345 -1188
454 4990 1866 -399 577 7892 3358 -1196
455 5015 1878 -404 578 7914 3370 -1204
456 5041 1889 -409 579 7936 3383 -1212
457 5066 1901 -414 580 7957 3396 -1220
458 5092 1913 -419 581 7979 3408 -1228
459 5117 1924 -424 582 8001 3421 -1236
460 5142 1936 -430 583 8023 3434 -1244
461 5167 1947 -435 584 8045 3447 -1252
462 5193 1959 -440 585 8067 3459 -1260
463 5218 1971 -445 586 8088 3472 -1268
464 5243 1982 -450 587 8110 3485 -1276
465 5268 1994 -456 588 8132 3498 -1284
466 5293 2006 -461 589 8154 3510 -1292
467 5318 2017 -466 590 8175 3523 -1300
142
468 5343 2029 -472 591 8197 3536 -1308
469 5368 2041 -477 592 8219 3549 -1317
470 5393 2053 -482 593 8240 3562 -1325
471 5418 2064 -488 594 8262 3574 -1333
472 5443 2076 -493 595 8283 3587 -1341
473 5468 2088 -499 596 8305 3600 -1350
474 5493 2100 -504 597 8327 3613 -1358
475 5517 2111 -510 598 8348 3626 -1366
476 5542 2123 -515 599 8370 3639 -1375
477 5567 2135 -521 600 8391 3652 -1383
478 5592 2147 -526 601 8413 3664 -1391
479 5616 2158 -532 602 8434 3677 -1400
480 5641 2170 -537 603 8455 3690 -1408
481 5665 2182 -543 604 8477 3703 -1417
482 5690 2194 -549 605 8498 3716 -1425
483 5715 2206 -554 606 8520 3729 -1434
484 5739 2218 -560 607 8541 3742 -1442
485 5763 2229 -566 608 8562 3755 -1451
486 5788 2241 -572 609 8583 3768 -1459
487 5812 2253 -578 610 8605 3781 -1468
488 5837 2265 -583 611 8626 3794 -1477
489 5861 2277 -589 612 8647 3807 -1485
490 5885 2289 -595 613 8668 3820 -1494
491 5910 2301 -601 614 8690 3833 -1503
492 5934 2313 -607 615 8711 3846 -1511
493 5958 2324 -613 616 8732 3859 -1520
494 5982 2336 -619 617 8753 3872 -1529
495 6006 2348 -625 618 8774 3885 -1538
496 6030 2360 -631 619 8795 3898 -1546
497 6055 2372 -637 620 8816 3911 -1555
498 6079 2384 -643 621 8837 3924 -1564
499 6103 2396 -649 622 8858 3937 -1573
500 6127 2408 -655 623 8879 3950 -1582
501 6151 2420 -661 62315 8883 3952 -1583
143
Appendix I
Table I1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in solid state (29815-35315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 1171 366 -017
299 035 010 000 328 1211 379 -018
300 076 023 000 329 1250 392 -019
301 117 035 000 330 1290 405 -021
302 158 048 000 331 1330 418 -022
303 199 060 000 332 1369 431 -023
304 240 072 -001 333 1409 444 -025
305 281 085 -001 334 1448 458 -026
306 322 097 -001 335 1488 471 -028
307 363 110 -002 336 1527 484 -029
308 404 122 -002 337 1566 497 -031
309 445 135 -002 338 1605 510 -032
310 486 148 -003 339 1644 524 -034
311 526 160 -003 340 1683 537 -036
312 567 173 -004 341 1722 550 -037
313 608 186 -005 342 1761 563 -039
314 648 198 -005 343 1800 577 -041
315 689 211 -006 344 1839 590 -043
316 729 224 -007 345 1877 603 -044
317 770 237 -007 346 1916 617 -046
318 810 250 -008 347 1955 630 -048
319 850 262 -009 348 1993 643 -050
320 891 275 -010 349 2031 657 -052
321 931 288 -011 350 2070 670 -054
322 971 301 -012 351 2108 683 -056
323 1011 314 -013 352 2146 697 -059
324 1051 327 -014 353 2184 710 -061
325 1091 340 -015 35315 2190 712 -061
326 1131 353 -016
144
Table I2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in liquid state (39115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
39115 4413 1056 -191 508 8890 3521 -978
392 4450 1535 -195 509 8924 3538 -986
393 4492 1549 -200 510 8959 3556 -995
394 4535 1566 -204 511 8993 3574 -1004
395 4577 1583 -209 512 9027 3591 -1013
396 4620 1599 -213 513 9062 3609 -1022
397 4662 1616 -218 514 9096 3626 -1031
398 4704 1633 -223 515 9130 3644 -1041
399 4746 1650 -227 516 9164 3661 -1050
400 4789 1666 -232 517 9198 3679 -1059
401 4831 1683 -237 518 9232 3697 -1068
402 4872 1700 -242 519 9266 3714 -1077
403 4914 1717 -247 520 9300 3732 -1087
404 4956 1734 -252 521 9334 3750 -1096
405 4997 1751 -257 522 9368 3767 -1105
406 5039 1767 -262 523 9402 3785 -1115
407 5080 1784 -267 524 9435 3802 -1124
408 5122 1801 -272 525 9469 3820 -1134
409 5163 1818 -277 526 9503 3838 -1143
410 5204 1835 -282 527 9536 3855 -1152
411 5245 1852 -287 528 9570 3873 -1162
412 5286 1869 -293 529 9603 3891 -1172
413 5327 1885 -298 530 9637 3908 -1181
414 5368 1902 -303 531 9670 3926 -1191
415 5409 1919 -309 532 9703 3944 -1201
416 5450 1936 -314 533 9737 3962 -1210
417 5490 1953 -320 534 9770 3979 -1220
418 5531 1970 -325 535 9803 3997 -1230
419 5571 1987 -331 536 9836 4015 -1240
420 5612 2004 -336 537 9869 4032 -1249
421 5652 2021 -342 538 9902 4050 -1259
145
422 5692 2038 -347 539 9935 4068 -1269
423 5732 2055 -353 540 9968 4086 -1279
424 5772 2072 -359 541 10001 4104 -1289
425 5812 2089 -365 542 10034 4121 -1299
426 5852 2106 -371 543 10066 4139 -1309
427 5892 2123 -376 544 10099 4157 -1319
428 5932 2140 -382 545 10132 4175 -1329
429 5971 2157 -388 546 10165 4192 -1340
430 6011 2174 -394 547 10197 4210 -1350
431 6051 2191 -400 548 10230 4228 -1360
432 6090 2208 -406 549 10262 4246 -1370
433 6129 2225 -412 550 10295 4264 -1380
434 6169 2242 -419 551 10327 4282 -1391
435 6208 2259 -425 552 10359 4299 -1401
436 6247 2276 -431 553 10392 4317 -1411
437 6286 2293 -437 554 10424 4335 -1422
438 6325 2310 -444 555 10456 4353 -1432
439 6364 2327 -450 556 10488 4371 -1443
440 6403 2344 -456 557 10520 4389 -1453
441 6442 2361 -463 558 10553 4407 -1464
442 6480 2378 -469 559 10585 4424 -1474
443 6519 2395 -476 560 10617 4442 -1485
444 6557 2412 -482 561 10648 4460 -1496
445 6596 2429 -489 562 10680 4478 -1506
446 6634 2446 -495 563 10712 4496 -1517
447 6673 2464 -502 564 10744 4514 -1528
448 6711 2481 -509 565 10776 4532 -1538
449 6749 2498 -515 566 10808 4550 -1549
450 6787 2515 -522 567 10839 4568 -1560
451 6825 2532 -529 568 10871 4586 -1571
452 6863 2549 -536 569 10902 4604 -1582
453 6901 2566 -543 570 10934 4622 -1593
454 6939 2584 -550 571 10965 4640 -1604
455 6977 2601 -557 572 10997 4658 -1615
456 7015 2618 -564 573 11028 4676 -1626
457 7052 2635 -571 574 11060 4694 -1637
458 7090 2652 -578 575 11091 4712 -1648
459 7128 2670 -585 576 11122 4730 -1659
460 7165 2687 -592 577 11154 4748 -1670
461 7202 2704 -599 578 11185 4766 -1681
146
462 7240 2721 -606 579 11216 4784 -1692
463 7277 2738 -614 580 11247 4802 -1704
464 7314 2756 -621 581 11278 4820 -1715
465 7351 2773 -628 582 11309 4838 -1726
466 7388 2790 -636 583 11340 4856 -1737
467 7425 2807 -643 584 11371 4874 -1749
468 7462 2825 -650 585 11402 4892 -1760
469 7499 2842 -658 586 11433 4910 -1772
470 7536 2859 -665 587 11464 4928 -1783
471 7573 2877 -673 588 11495 4946 -1794
472 7609 2894 -680 589 11525 4964 -1806
473 7646 2911 -688 590 11556 4982 -1817
474 7682 2928 -696 591 11587 5001 -1829
475 7719 2946 -703 592 11617 5019 -1841
476 7755 2963 -711 593 11648 5037 -1852
477 7792 2980 -719 594 11678 5055 -1864
478 7828 2998 -727 595 11709 5073 -1876
479 7864 3015 -735 596 11739 5091 -1887
480 7900 3032 -742 597 11770 5109 -1899
481 7937 3050 -750 598 11800 5128 -1911
482 7973 3067 -758 599 11831 5146 -1923
483 8009 3084 -766 600 11861 5164 -1935
484 8045 3102 -774 601 11891 5182 -1946
485 8080 3119 -782 602 11921 5200 -1958
486 8116 3137 -791 603 11952 5218 -1970
487 8152 3154 -799 604 11982 5237 -1982
488 8188 3171 -807 605 12012 5255 -1994
489 8223 3189 -815 606 12042 5273 -2006
490 8259 3206 -823 607 12072 5291 -2018
491 8294 3224 -832 608 12102 5309 -2030
492 8330 3241 -840 609 12132 5328 -2042
493 8365 3259 -848 610 12162 5346 -2055
494 8401 3276 -857 611 12192 5364 -2067
495 8436 3293 -865 612 12222 5382 -2079
496 8471 3311 -873 613 12252 5401 -2091
497 8506 3328 -882 614 12281 5419 -2103
498 8542 3346 -890 615 12311 5437 -2116
499 8577 3363 -899 616 12341 5456 -2128
500 8612 3381 -908 617 12370 5474 -2140
501 8647 3398 -916 618 12400 5492 -2153
147
502 8681 3416 -925 619 12430 5510 -2165
503 8716 3433 -934 620 12459 5529 -2178
504 8751 3451 -942 621 12489 5547 -2190
505 8786 3468 -951 622 12518 5565 -2203
506 8820 3486 -960 623 12548 5584 -2215
507 8855 3503 -969 62315 12552 5602 -2217
viii
LIST OF TABLES
21 Melting point of various nitrate salt systems 12
22 Melting point of various carbonate salt systems 13
23 Melting point of various fluoridechloride salt systems 14
24 Melting point of various hydroixde salt systems 15
25 Density coefficients A and B of nitrate salts 16
26 Density coefficients A and B of carbonate salts 17
27 Density coefficients A and B of chloridefluoride salts 17
28 Density coefficients A and B of molten salt mixture with hydroxide salts 18
29 Heat capacity of alkali nitrate salt at 500oC 19
210 Heat capacity of alkali carbonate salt at 500oC 19
211 Heat capacity of fluoridechloride salt at 500oC 20
212 Heat capacity of hydroxide salt at 500oC 21
41 Calculated composition and melting point for multi-component systems 29
61 Calibration data of melting points with different samples 35
62 DSC results of melting point transition point and change of enthalpy 41
ix
63 Fusion and solid phase transition temperature for individual salts 42
64 Melting points of candidate systems as function of temperatures 51
65 Calibration data of heat capacities with different samples 52
66 Heat capacity of selected new TES molten salt mixtures 54
67 Change of Gibbs energy values at 62315K for molten salt systems 85
68 Calibration of density measurements with different pure nitrate salts 86
69 Coefficient of A and B for density determination of salt 1 to salt 9 87
610 Extrapolated value of density and heat capacity at 500oC of salt 1 to salt 9 91
611 Energy density of salt 1 to salt 9 compare to solar salt 92
612 Gravimetric storage densities for solar salt and new molten salts 93
x
LIST OF FIGURES
11 Theoretical and engineering energy conversion efficiency as function of temperature 6
12 Gravimetric storage density for different energy storage systems
as function of temperature 8
51 Photography of set-up for DSC equipment 31
61 Melting point calibration with indium sample 34
62 Melting point calibration with KNO3 sample 35
63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt 36
64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt 37
65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt 37
66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt 38
67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt 38
68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt 39
69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt 39
610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt 40
611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN Salt 40
612 DSC plot of 698wt KNO3 -302wt NaNO2 binary system 43
xi
613 DSC plot of 270wt NaNO3-730wt KNO3 binary system 45
614 DSC plot of 458wtLiNO3-542wtKNO3 binary system 45
615 DSC plot of 460wt NaNO3-540wt KNO3 binary system 46
616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 20oCmin heating rate 47
616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 5oCmin heating rate 48
617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 5oCmin heating rate 49
617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 20oCmin heating rate 49
618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system
as function of temperature 53
619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K 54
620 Change of Gibbs energy as function of temperature for molten salt systems 85
621 The densities of the salt 1 to salt 5 as function of temperature 87
622 The densities of the salt 6 to salt 9 as function of temperature 89
623 Densities of the salt 1 salt 2 as function of temperature compared to
the equimolar NaNO3-KNO3 binary system and pure KNO3 90
624 Gravimetric storage density comparison of different energy storage
xii
systems as function of temperature 93
1
CHAPTER 1
INTRODUCTION
Renewable energy sources such as wind solar water power geothermal and biomass are
playing more and more significant role in our energy supply Because the cheap cost and infinite
amount of energy storage inside the resource solar energy is emphasized since 20th
century and
viewed as promising alternative method to satisfy the large energy consumption every day in the
world reduce the emission of carbon and strengthen the economy
The wind energy was used as a clean energy to generate electricity back to late 19th
century
However this renewable energy source was not emphasized due to the cheap price of fossil fuel
The re-emergence happened in mid 1950s when the amount of traditional energy source was
found apparently decrease The development of wind energy usage continued and in 1990 the
first mega-watt wind turbine was launched which was viewed as a symbol of shift to large scale
wind energy utilization [1-2] The modern application of wind energy mainly relies on wind
turbine On the basis of aerodynamic wind turbine generates certain net positive torque on
rotating shaft and then converts the mechanical power to electrical power As an electrical power
generator wind turbine is connected to some electrical network to transport the electricity to
battery charging utilities residential power systems and large scale energy consuming systems
In general most of wind turbines are small scale and can only generate 10KW electrical power
Only few of the wind turbine systems operate with capacity as large as 5MW Although the
usage of wind energy can reduce the emission of carbon oxide the noise pollution and high cost
2
limit its large scale application Since the wind is not transportable the electrical energy can only
be generated where the wind blows which also decrease the flexibility of wind energy
Water power is another term of alternative power supply and it was used for irrigation
operating machines like watermill even before the development of electrical power The modern
application of water power is to generate electricity by using the gravitational force of falling or
flowing water These days there are various ways for the water power application The most
traditional method is to store the water in dam and generate electricity by converting the
potential energy pump storage is a different way to utilize water power and can change its
output depending on the energy demand by moving water between reservoirs at different
elevations In the low energy demand period excess energy is used to lift water to the higher
level while in the peak period of energy demand the water is released back to the lower
elevation through water turbine Water power can also be converted by taking advantage of
naturally raise and fall of tide to satisfy the demand of electrical energy consumption [3]
Although the usage of water power can reduce the emission of carbon dioxide and cost it will
destroy the ecosystem because of the large land required for construction There will be methane
emission from the reservoir the potential failure hazard of dam is also a fatal issue and flow
shortage caused by drought may also create serious problem As result of that water power
technique is not a long-term alternative choice
Geothermal energy is the energy form generated inside the earth At the very beginning of
the planet formation a large amount of thermal energy was stored from the radioactive decay of
minerals volcanic activity and solar energy absorption Because of the temperature difference
3
between the core and the surface of planet the thermal energy stored inside the earth is driven to
the outer surface in the form of heat This form of renewable energy source can be applied to
generate electrical power and heat for industrial space and agricultural applications
Theoretically the deposited amount of geothermal energy is adequate to supply the energy
consumption in the world However most of the geothermal energy is stored deeply near the
core of the earth the deep drilling and exploration of geothermal energy is very expensive and
limits the large-scale use of this renewable energy source [4]
Biomass is a renewable energy source used to generate heat or electricity with living or
recently living organism such as wood waste (hydrogen) gas and alcohol fuels The biomass
energy can be converted to electrical energy by thermal method such as combustion pyrolysis
and gasification Several specific chemical processes may also be able to convert the biomass
energy to other forms The main problem arise from application of biomass is air pollution which
contains carbon monoxide NOx (nitrogen oxides) VOCs (volatile organic compounds)
particulates and other pollutants And the level of air pollution to some extent is even above that
of traditional fuel resource Some other possible issue like transportation and sink of carbon also
limit the wide usage of this type of alternative energy [5]
Among all the renewable energy sources solar energy is the most suitable alternative
energy for our future life It is clean cheap abundant without any noise air pollution no
transportation issue and easy to be obtained anywhere in the earth Inside the core of the Sun
hydrogen fuses into helium with a rate of 7times1011
kgs and generates very powerful nucleation
power This type of nucleation explosion creates ultra high temperature in the core of the Sun
4
which reaches approximately 16 million K degrees Although the Sun is not perfectly black body
it still radiates abundant power with the energy density as 16times107 wattsm
2 [6-7] Because of the
enough amount of hydrogen underneath the surface of the Sun the radiation given arise of from
the nucleation explosion can continue at least 5 million years with the same rate and strength
The energy reaching the earth is vastly reduced mainly caused by the absorption and spreading
of the radiation It is easily to understand that there are numerous amorphous objects all around
the entire universe which can absorb certain portion of the radiation for the Sun Moreover the
light generated from the spherical object such as the Sun fills all the available space between the
origin to the destination Even though the energy will not be lost in the travelling process due to
the long distance between the Sun to the earth the surface area of the sphere which is formed
with the Sun as center and the distance as radius is much larger than that of the earth As the
result of that only 1340Wm2 finally reaches the upmost surface of the earth Even though the
final amount of the received solar energy is very small compared to that is initially radiated from
the Sun the average daily solar radiation falling on one area in the continental United States is
equivalent in total energy content to 11 barrels of oil In summary the solar energy itself is
relatively unlimited useful clean and almost unexploited energy and definitely can behave as
the promising mean for the future energy supply [8]
There are several different methods to take advantage of the solar energy and all the
methods can be distinguished into three group solar parabolic trough solar tower and solar dish
Parabolic trough is constructed by silver coated parabolic mirror and there is a Dewar tube going
through the length of the mirror and set on the focal point all the radiation is concentrated on the
tube and transfer by heat transfer fluid to the thermal energy storage unit Solar tower are used to
5
capture solar energy with thousands of mirrors and focus the concentrated sunlight to the top of
the tower which is located in the middle of the heliostats The thermal energy storage medium
within the tower was heated to high temperature and transferred to thermal energy storage tank
and eventually sent to steam pump The solar dish is built with a large reflective parabolic dish
which concentrates all the received sunlight to one spot There is normally a receiver located on
the focal point and transform the solar energy to other forms of useful energy The working
upper limit temperature of solar parabolic trough system is the lowest among these three systems
normally its maximum working temperature is within the range from 400-500oC the solar tower
has higher maximum working temperature which ranges from 500-1000oC the solar dish has the
highest working upper limit temperature which reaches 700-1200oC [9]
The energy conversion efficiency is the most concerned parameter in the solar energy
storage application and the theoretical and real engineering efficiency are given in fig 11 as
function of temperature The theoretical conversion efficiency can be up to 80 while in real
application the value is always less than 70 regardless of collectors The actual efficiency
increases with temperature in the whole working temperature As a result of that the thermal
energy storage materials in solar parabolic trough for instance should be able to work stably at
the upper limit temperature of this type of collection system which is 500oC to ensure the highest
efficiency [9 10]
6
Fig 11 Theoretical and engineering energy conversion efficiency as function of
temperature
Solar energy can be stored in three major forms sensible heat latent heat and
thermochemical heat Sensible heat storage was utilized based on the heat capacity and the
change as function of temperature of storage materials in the charging and discharging process
which correspond to the absorbing and withdrawing energy processes respectively The sensible
heat stored from the melting point to the maximum working temperature can be expressed by
equation 1 [9]
[1]
Where m is the mass of storage material Tmp and TH are melting point temperature and high
temperature in the same phase respectively Cp(T) is the heat capacity at different temperature
Because the sensible heat storage materials remain in a single phase in the working temperature
range the charging and discharging processes are completely reversible for unlimited cycles
7
Latent heat storage is operated by absorbing and withdrawing energy in the charging and
discharging processes accompanied with fusion of materials [9] The latent heat collected
throughout the working temperature range can be expressed by equation 2 as following
[2]
Where T is temperature in solid state Tmp is melting point temperature of storage material TH is
the high temperature in liquid state and is enthalpy of fusion
Thermochemical heat storage is based on the heat capacity and its change as function of
temperature accompanied with chemical reaction The thermochemical heat collected throughout
the working temperature range can be expressed by equation 3
[3]
Where TL is the low temperature before the reaction TR is the reaction temperature and
is the enthalpy of chemical reaction Because of the destruction of the chemical bonds
in the reaction process the charging and discharging process cannot be completely reversible
which reduces the stability and recyclability of storage operation [10]
Sensible energy storage method is chosen to ensure the efficient usage of solar energy for
parabolic trough system of which the maximum working temperature ranges from 400-500oC
Different from thermochemical heat storage the sensible heat storage can achieve completely
reversible working condition under unlimited cycles Also fig 12 illustrates that the sensible
heat storage materials mainly work in the working temperature range for parabolic trough system
8
and the gravimetric energy storage densities of sensible heat is higher than that of latent heat
materials [9 -11]
Fig 12 Gravimetric storage density for different energy storage systems as function of
temperature
Various materials are chosen to serve as thermal energy storage fluid for sensible heat
such as water thermal oil ionic liquid and molten salt [12] The properties of different heat
transfer fluid determine the performance of solar energy heating system In these days the
efficiency and cost of output of electrical power mainly relies on the parabolic trough solar
power plant and the thermal storage fluid [12] A large investment cost is needed to dispatch
100MW to 200MW energy by consuming the energy transfer fluids Given by this situation the
development of new thermal storage fluid with higher thermal energy storage density is
paramount to lower the expense for generating energy and a lot of effect has been put on design
of new systems [13-16]
9
Water is commonly used as heat transfer and thermal energy storage fluid in industry
because of its low cost high heat capacity and high thermal conductivity However the
limitation for using this medium is also obvious that the temperature range within which the
liquid state can be assured is too small It is well know that water can only serve as thermal
energy storage liquid above the freezing point 0oC and below the boiling temperature 100
oC In
practical experiment the actual temperature range is even less than 100oC because of the large
amount of weight loss near the boiling temperature due to the high vapor pressure Water is
possible to work above 100oC only if high pressure is also applied to avoid the phase
transformation but the cost will be highly increased Accordingly water is only suitable to work
in low temperature below 100oC
Thermal oils are also being used in the parabolic trough solar power plant and have very
low melting point as low as 12oC [17 18] However the application of the oil for the thermal
energy storage liquid is limited by some disadvantages from the physic-chemical properties The
upper limit for this oil is only 300oC and above that the liquid state cannot be maintained
Moreover the low thermal decomposition temperature low density and low heat capacity result
in limited thermal energy storage capacity Since the working temperature range is so narrow the
rankie cycle efficiency is reduced when using the synthetic oil and the cost for generating power
is considered to be very expensive [19 20]
Ionic liquid is another medium served as thermal energy storage fluid The liquid
temperature range of ionic liquid is large which is one of the main advantages of this type of
material The high heat capacity and density ensure the efficiency of thermal energy storage of
10
ionic liquid What‟s more the excellent chemical stability and little vapor pressure increase the
lifetime [21-24] However as a result of the very serve corrosion problem to the liquid container
and the high cost the usage of ionic liquid is still limited
Considering various relative physic-chemical properties of thermal energy storage system
molten salts have been proposed as a suitable group for a wide temperature range application
They are being emphasized in the solar energy applications because of their low melting point
and high upper limit which can increase the stable working range The high heat capacity
increases the thermal energy storage density of the heat storage system excellent thermal
stability and negligible vapor pressure ensure the steadiness of cyclic repeating in the lifetime
[25] low viscosity strengths the mobility and efficiency of the thermal storage liquid low
utilization cost reduce the investment and protect the economy The liquidus temperature range
of the molten salt varies from 150-600oC combination of various salts can bring the melting
down and further increase the working temperature range Due to these properties molten salts
can be excellent thermal energy storage fluid in the solar power generation system
11
CHAPTER 2
LITERATURE REVIEW
Several physical and thermodynamic properties of thermal energy storage fluid play
significant role in determining the efficiency and performance of solar energy storage systems In
order to evaluate the feasibility of systems the physic-chemical properties of several molten salts
should be reviewed The three determining parameter which directly affect the thermal energy
storage capacity in systems are melting point heat capacity and density
There are large amount of melting point data available in the literature for various molten
salt system in previous literatures while those with melting point less than 120oC is very limited
All the previous study on molten salt system revealed that five group of molten salts are
emphasized and commonly used alkai or alkaline nitrates carbonates sulphates chloride and
hydroxides Although most of the systems have the same group of cation the melting point
varies a lot from one to anther due to the different effect of anions
21 Melting point
The melting points of individual and multi-component nitratenitrite systems are listed in
Table 21[26-31] Among those systems solar salt (NaNO3KNO3 6040) is the thermal energy
storage medium which is currently being used with the freezing point of 221oC [27] Although
the melting point for this system is highest in all the candidate mixtures in this group the lowest
12
combined compound cost makes it widely used in solar energy storage field Another ternary
system HITEC which contains NaNO3 KNO3 and NaNO2 has freezing point of 141 oC [28]
This combination brings the melting point down but the lack of combination of optimum features
limits its further application [29] Some mixtures such as LiNO3-Ca(NO3)2-KNO3 are not often
utilized because they increase the compound cost at the same time of lowering the melting point
to around 120oC [30] moreover the decreased melting point is still high compared to the
organic oil There are also several systems have the melting points less than 100oC or even 60
oC
they are not used in the parabolic trough solar power plant due to the decomposition of some
components during high temperature [31]
Table 21 Melting point of various nitrate salt systems
Compound Melting Point (ordmC)
LiNO3 253
NaNO3 307
KNO3 334
Ca(NO3)2 561
Sr(NO3)2 570
Ba(NO3)2 590
NaNO3-NaNO2 221
NaNO3-NaNO2-KNO3 141
NaNO3-KNO3-CaNO3 133
LiNO3-KNO3-NaNO3 120
KNO3-CaNO3-LiNO3 117
LiNO3-KNO3-NHNO3 92
KNO3-NHNO3-AgNO3 52
The melting points of individual and multi-component carbonate systems are listed in
Table 22 [26 32 33] Different from the nitrate salts the melting points for both the individual
13
and multi-component carbonate systems are on the higher side The lowest melting point is
achieved with lithium sodium and potassium carbonate ternary system whose melting point is
still 277oC higher than that of the nitrate ternary system with the same cations [32] Besides
because of the thermal decomposition issue the choice of component involved in the multi-
component carbonate systems is limited Some salt like CaCO3 doesn‟t have stable form at high
temperature and the lack of multi-component system reduces the chance of the synthesis of low
melting point salt mixtures Even though this group of salt is not thermally stable and the
working temperature range is relatively small it is still viewed as possible candidate working at
high temperature due to its low price
Table 22 Melting point of various carbonate salt systems
Compound Melting Point (ordmC)
Li2CO3 732
Na2CO3 858
K2CO3 900
MgCO3 990
Na2CO3-K2CO3 710
Li2CO3-Na2CO3 496
Li2CO3-K2CO3 488
Li2CO3-K2CO3-Na2CO3 397
Alkali and Alkaline fluoridechloride salts are also selected as one possible choice as the
thermal energy storage fluid and the melting point examined from previous literatures are given
in table 23 [34-38] A lot of study has been done for this group of salt and the melting points
were found in the same range as the carbonate group And for the pure salt metal chloride salts
have lower melting point than metal fluoride ones
14
Table 23 Melting point of various fluoridechloride salt systems
Compound Melting Point (ordmC)
LiF 849
NaF 996
KF 858
LiCl 610
NaCl 801
KCl 771
LiF-KF 493
LiF-NaF 652
LiCl-KF 487
LiF-NaF-KF 454
LiF-NaF-KF-MgF2 449
LiF-KF-BaF2 320
LiF-KF-CsF-RbF 256
Several studies were also conducted to determine the melting point of molten hydroxide
salts and the results are shown in Table24 The data of pure salts and multi-component mixtures
merely in this group were not much determined in the literatures Generally they are mixed with
other groups of anion and form some low melting point salt mixtures [39-42] On the basis of the
previous literature data alkali hydroxide salts and their mixture with salts in other groups have
relatively lower melting point compared with pure carbonate and fluoride chloride group salt
mixtures Most of the melting points given in Table 4 are lower than 300oC sodium potassium
hydroxide binary mixture even reaches the melting point below 200oC Accordingly relatively
large temperature range can be obtained by using hydroxide salt mixtures or adding them as
additive
15
Table 24 Melting point of various hydroixde salt systems
Compound Melting Point (ordmC)
LiOH-LiF 427
NaOH-KOH 170
LiOH-NaOH 213
NaOH-NaNO2 232
NaOH-NaNO3 237
NaOH-NaCl-NaNO3 242
NaOH-NaCl-Na2CO3 282
22 Density
For the solar energy storage system density for the thermal energy storage fluid is also
essential parameter The density is needed for the size calculation as function of temperature and
assessing for the thermal stability of thermoclines Besides density as function of temperature is
used to evaluate the volume change in the process of freezing which contributes to potential
stress
Alkalialkaline nitrate salts were studied very much about their density as function of
temperature All the results indicate that the density was decreased linearly as temperature
increases and any specific density value in the molten state can be expressed by equation as
equation 4
= A-BT [4]
Where (gcm3) is the density of salt A (gcm
3) is the initial density value at 0
oC and B
(mgcm3degC) is the density change slope as function of temperature The coefficients are shown in
16
Table 25 for the nitrate group molten salts Among these systems pure sodium nitrate has the
largest value which reveals the high initial density value at low temperature [43] Conversely
lithium nitrate has the lowest value while it presents the smallest decrease trend as temperature
increases [44] The densities and A B values of multi-component nitrate salts were included in
the range of those two salts discussed above
Table 25 Density coefficients A and B of nitrate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiNO3 1922 0556
NaNO3 2334 0767
KNO3 2127 0760
NaNO3-KNO3 2134 0773
KNO3-CaNO3-LiNO3 2172 0735
LiNO3-KNO3-NaNO3 2083 0715
Several experiments were also conducted to measure the density as function of temperature
for the individual and multi-component carbonate salt systems The density of the carbonate salt
also follow the same trend as that of nitrate salt and the temperature dependence of density
followed the linear equation as discussed above It is observed that all the carbonate salts have
higher initial density coefficient A than the nitrate salt The largest value is reached to 2511 and
even the lowest value in this group is greater than the maximum A of nitrate group [45-49]
What‟s more the regression slope coefficient B of carbonate salt is lower compared to that of the
nitrate salt group Accordingly the salts in this group present larger density in the molten state
and the density coefficient A and B are given in Table 26
17
Table 26 Density coefficients A and B of carbonate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
Li2CO3 2303 0532
Na2CO3 2350 0448
Na2CO3-K2CO3 2473 0483
Li2CO3-K2CO3 2511 0599
Li2CO3-Na2CO3 2456 0519
Li2CO3-Na2CO3-K2CO3 2364 0544
Density of metal fluoride and chloride molten salt were also examined and present similar
regression trend as temperature increases The linear temperature dependence is also expressed
by the same equation On the basis of previous literature data the pure chloride salt shows lower
density than the fluoride salt with the same cation in the molten state [49] What‟s more the
sodium halide salt has the largest density value while the lithium halide salt has the lowest value
which is very similar to the nitrate group salt The density determination coefficient A and B are
given in Table27
Table 27 Density coefficients A and B of chloridefluoride salts
Compound A(gcm3) Btimes103(gcm
3degC)
LiCl 1766 0432
NaCl 1991 0543
KCl 1976 0583
LiF 2226 0490
NaF 2581 0636
KF 2469 0651
LiF-NaF 2520 0818
LiCl-NaF-KCl 2436 0742
LiF-NaF-MgF 2240 0701
18
The density measurement of hydroxide was not conducted as much as those three anion
groups discussed above Only few data of density is available for the alkali hydroxide salt when
added into other salt systems and temperature dependence also follows the linear regression
trend [32 41] The density determination coefficient A and B are given in Table 28
Table 28 Density coefficients A and B of molten salt mixture with hydroxide salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiCl-LiOH 16 0443
LiF-LiOH 165 0471
23 Heat capacity
In the heating process the temperature of solar energy storage molten salt is increase by
absorbing energy from the solar radiation Conversely the same amount of heat is released and
applied to heating system in the process of cooling Heat capacity is the amount of heat required
to increase the temperature of certain material by 1 oC and can be viewed as the directly relevant
parameter to the energy storage ability To some extent the large heat capacity assures the
efficiency of the application of solar energy storage materials
The heat capacity of alkalialkaline nitrate salt was investigated for both individual and
multi-component system in the previous literature To simplify the comparison only the heat
capacity value at 500oC is shown in all the following tables In the liquid state the heat capacity
increases with temperature following linear equation and the increasing slope is as small as 10-5
to 10-4
[50 51] Among those alkali nitrate salt systems lithium nitrate has the largest heat
19
capacity at 500oC while potassium nitrate presents the lowest value at that temperature In table
29 the heat capacity results at the selected temperature in literature are given
Table 29 Heat capacity of alkali nitrate salt at 500oC
Compound Heat capacity(JgK)
LiNO3 2175
NaNO3 1686
KNO3 1400
NaNO3-KNO3 1533
LiNO3-KNO3 1642
LiNO3-KNO3-NaNO3 1681
For the carbonate salt systems in the molten state the heat capacity is almost constant and
almost independent with temperature [32 33] Same as the nitrate group salts the heat capacity
for pure carbonate salt decreases as the atomic number of the alkali element increases which
means the value for lithium carbonate is the largest and that of potassium carbonate is the
smallest Generally the heat capacity value for carbonate in molten state is larger than that in
solid state However the sodium-potassium carbonate binary system is an exception for which
the heat capacity in solid state is larger than liquid state In table 210 the heat capacity results of
carbonate salts at the selected temperature in literature are given
Table 210 Heat capacity of alkali carbonate salt at 500oC
Compound Heat Capacity(JgK)
Li2CO3 250
Na2CO3 178
K2CO3 151
Na2CO3-K2CO3 157
20
Li2CO3-K2CO3 160
Li2CO3-Na2CO3 209
Li2CO3-K2CO3-Na2CO3 163
The heat capacity of fluoridechloride salt was measured in several literature and found
that for the pure salt the lithium halide has the biggest heat capacity data in the molten state
while the potassium halides shows the lowest heat capacity value Similar to the carbonate group
the heat capacity value of fluoridechloride salt varies little with temperature in the liquid state
[32 33] The values at 500oC for the alkalialkaline halides are shown in Table 211
Table 211 Heat capacity of fluoridechloride salt at 500oC
Compound Heat Capacity (JgK)
LiCl 148
NaCl 115
KCl 090
LiF-KF 163
NaCl-MgCl2 100
LiF-NaF-KF 155
KCl-MgCl2-CaCl2 092
The heat capacity of pure and multi-component hydroxide salt systems is limited in the
previous literature and the values in the liquid state follow linear equation which is observed for
all the molten salt discussed above [52] The values at 500oC for the alkalialkaline halides are
shown in Table 212
21
Table 212 Heat capacity of hydroxide salt at 500oC
Compound Heat Capacity(JgK)
NaOH 188
LiOH-NaOH 221
NaOH-KOH 182
In summary on the basis of comparison of various physic-chemical properties molten
nitrate slats have relatively low melting point excellent working temperature range reasonable
density and high heat capacity As the result of that molten nitrate salt is suitable to be applied as
the thermal energy storage fluid in the solar energy storage system
22
CHAPTER 3
OBJECTIVES
Based on review of previous literature data it is found that there are several disadvantages
such as the high melting point relatively low density value or poor heat capacity in liquid state
which limit the application of molten salt in certain groups in solar thermal energy storage
system Conversely alkalialkaline nitrate salt is considered as the suitable choice and proposed
as the thermal energy storage liquid for high temperature
Currently the used thermal energy storage liquid is NaNO3 (60mol)-KNO3 (40mol)
binary system (solar salt) which has the melting point at 221oC [30] Although the melting point
for this salt mixture is not the lowest it is still emphasized because of its low investment cost
However there are some drawbacks for this binary nitrate mixture The main disadvantage is
the high melting point In evenings or in winter the molten salt can easily freeze and block the
pipeline As a result of that some auxiliary cost should be added to overcome this problem and
the total investment will be increased
Development and synthesis of newer molten salt mixtures with freezing point lower than
those currently used for thermal energy storage applications is necessary for higher efficiency of
utilization of solar energy and getting rid of any unnecessary cost The approach to develop
lower freezing point molten salt mixtures is by the prediction of new eutectic mixtures and also
23
by the development of new nitrate compounds Besides these two most well known systems
several other mixtures were also studied Preliminary evaluation of several new molten salt flux
systems based on requirements for thermal energy storage systems mainly including freezing
point density heat capacity viscosity and thermal energy storage density The promising
candidate low melting point molten salt system should satisfy the requirements that eutectic
melting temperatures are lower than 220oC and the thermal energy storage densities are higher
than binary solar salt It is known that the melting point can be lowered by the addition of one or
more ABNO3 nitrate compounds where A and B are cations Consequently several multi-
component systems which have more constituent salts than solar salt were came up with and
studied with little fundamental data on the physic-chemical properties at the required operating
conditions available at present
In this thesis the new systems with simulated eutectic compositions were tested for their
experimental melting points heat capacities using the Differential Scanning Calorimetry (DSC)
technique which is considered to be the accurate instrument for thermodynamic data analysis
[53-59] Some significant thermodynamic properties such as heat capacity enthalpy and entropy
and Gibbs energy were calculated in the thesis to evaluate the energy change of the system in the
phase change process and the potential of being applied in the parabolic trough solar power plant
The energy density was obtained by using the experimental measured density and heat capacity
of the mixtures in molten state Finally 9 down-selected systems were present and discussed
24
CHAPTER 4
THERMODYNAMIC MODELING OF SALT SYSTEMS
41 Thermodynamic modeling
To lower the melting point of solar energy storage system multi-component system is
applicable Thermodynamic model was introduced to predict the eutectic temperature of salt
systems based on the Gibbs energies of fusion of individual salt and that of mixing of constituent
binary systems At the eutectic temperature the Gibbs energies in the liquid state and solid state
of salt are equal In thermodynamics Gibbs energy of fusion can be expressed by the equation
given as follows
G = H-TS [5]
Where H is the change of enthalpy of fusion and S is the change of entropy of fusion Equally
the entropy change of fusion can be expressed by differentiating G and the equation is given
[6]
It is known that the change in entropy can be expressed in terms of change in heat capacity in the
melting process as
[7]
25
If the change of heat capacity is assume to be independent of temperature the integral of
from Tm to T can be shown as
[8]
where Sm is the entropy of fusion at the melting point which is equal to Accordingly
Eq8 can be rewritten as
[9]
Substituting Eq 9 in Eq 6 and integrating the equation from Tm to T we get
[10]
Eq 10 illustrates that by using the change of heat capacity melting point and enthalpy of fusion
the Gibbs energy change at any temperature can be obtained
The standard Gibbs energy of fusion of a salt bdquo1‟ can be expressed in terms of the activity
of the salt as
[11]
where is the molar excess Gibbs energy and X1 is the molefraction of the salt bdquo1‟ Gibbs
energy of fusion at any give temperature T is expressed by Eq 7 in terms of its molefraction and
partial molar excess Gibbs energy
26
Take LiNO3-NaNO3-KNO3 as an example in which the integral molar excess Gibbs energy is
composed of the summation of the Gibbs energies of three constituent binary system and one
ternary The expression of the integral excess Gibbs energy is given by Eq12
[12]
Gibbs energies of the three constituent binary systems LiNO3-NaNO3 LiNO3-KNO3 and
NaNO3-KNO3 of the LiNO3-NaNO3-KNO3 ternary system are taken from the literature [48 49]
The Gibbs energies of mixing or the integral excess Gibbs energies of the three constituent
binary systems of the LiNO3-NaNO3-KNO3 ternary system are given below
LiNO3-NaNO3 Binary System
Jmol [13]
LiNO3-KNO3 Binary System
Jmol [14]
NaNO3-KNO3 Binary System
Jmol [15]
When assume the intergral excess Gibbs energy of to be zero the excess Gibbs energy in
the ternary system can be expressed by the summation of three constituent binary systems
[16]
27
Generally the partial molar excess Gibbs energies are reduced from the integral molar
excess Gibbs energy and can be expressed by the generalized equation for certain ldquomrdquo
component salt as
[17]
In the ternary system the i value equals to 12 and 3 and the partial molar excess Gibbs energy
of mixing for each component can be expressed as follows
[18]
[19]
[20]
Based on Eq 7 and the partial molar excess Gibbs energy of individual component the
Gibbs energy in the fusion can be expressed as Eq21- 23
[21]
[22]
[23]
42 Calculations
The fusion of the ternary salt system is defined by solutions of Eq 21-Eq 23 Newton-
Raphson method can be used to solve these three non-linear equations by linearizing the non-
linear equations using the Taylor series and truncating the series to first order derivatives
28
Consider the three non-linear functions F G and H in three variables x y and z The three
equations that are solved for the three variables are written as
F(x y z) = 0
G(x y z) = 0
H(x y z) = 0 [24]
The partial derivatives of the function F with respect to x y and z are given as
[25]
Similarly the partials derivatives can be expressed for the other two functions G and H
Newton-Raphson iterative method of solving the three equations in three variables
essentially deals with the solution of the incremental vector in the matrix equation given below
[26]
For the initial values of x y and z (say xi yi and zi) the right hand side vector contains the
values of the functions at the initial values (xi yi and zi) The 3times3 matrix on the left hand side
contains the partial derivatives of the functions with respect to the three variables at the initial
values Solutions of the matrix equation (Eq 26) result in the increments of the variables x y
and z The variables for the next iteration will then be xi + x yi + y and zi + z The
process of solving the matrix equation (Eq 26) is continued until the increments in the variables
x y and z is less than a very small quantity The iteration process is then said to be
29
converged and the values of the variables at convergence of the solution are the roots of the
system of the three fusion equations
The composition of LiNO3 NaNO3 and KNO3 and the eutectic temperature is solved by
using the Newton-Raphson iterative method Different from the data in previous literature the
eutectic temperature for the ternary is 116oC Besides the composition for each component is
also different from those published in literatures The new molten ternary system is composed of
2592 wt LiNO3 2001 wt NaNO3 and 5407 wt KNO3 The similar method is also applied
to other multi-component systems to determine the composition and eutectic temperature The
predicted melting points for new solar energy storage system are given Table41
Table 41 Calculated composition and melting point of multi-component molten salts systems
System Composition (wt) Calc Tmp
LiNO3 NaNO3 KNO3 NaNO2 KNO2 Mg(NO3)2 MgKN (degC)
Salt 1 259 20 541 - - - - 116
Salt 2 - 161 547 292 - - - 1238
Salt 3 175 142 505 178 - - - 986
Salt 4 115 104 274 - - - 507 986
Salt 5 172 139 476 172 41 - - 957
Salt 6 9 423 336 - 151 - - 1000
Salt 7 193 - 546 237 24 - - 1081
Salt 8 193 - 559 239 - 09 - 1008
Salt 9 154 172 324 - - 83 267 1036
30
CHAPTER 5
EXPERIMENTAL PROCEDURE
51 Melting point determination of molten salt mixtures
511 Materials
Ternary quaternary and quinary nirate and nitrite mixtures were tested in the thesis Most
components in the mixtures don‟t require any pre-preparation and can be used as received The
only exception is new developed MgKN which was composed of 6667 mol KNO3 and 3333
mol Mg(NO3)2 This unique compound is synthesized from magnesium nitrate hexahydrate
(98 Alfa Aesar) and potassium nitrate (ACS 990 min Alfa Aesar) and added into the
mixture as one single component As received magnesium nitrate hexahydrate is dehydrated
before synthesizing MgKN compound Weighted amount of magnesium nitrate taken in a
stainless steel crucible and placed on a hot plate in an argon atmosphere Temperature of the salt
is measured with a thermocouple immersed in the salt The temperature was held at 52315 K for
2 hours The salt solidifies to a white mass The temperature of the salt is then raised to 57315 K
slowly to remove any traces of moisture and to ensure complete dehydration The complete
removal of water is ascertained by weight loss
512 Apparatus and Procedure
31
Differential scanning calorimetry (DSC) analysis was performed using Perkin Elmer
Diamond DSC instrument and the setup is shown in fig 51 Heat flow and temperature can be
recorded in the instrument with an accuracy of 00001 mW and 001 K respectively The
measurements were made under purified nitrogen atmosphere with a flow rate of 20ccmin and at
a heating rate of 5 Kmin
Fig 51 Photography of set-up for DSC equipment
After dehydration if necessary each component was weighed to an accuracy of 01mg with
the electrical balance and mixed thoroughly in a stainless steel crucible Later the mixture is
heated up to certain temperature at which the entire salt melts At this temperature the salt
mixture was held for about 30 minutes The salt mixture is allowed to air cool to ambient
temperature This procedure is repeated 3 to 4 times to get the well-mixed compound Standard
aluminum pan with lid used for DSC measurements are weighed before the experiment Small
amount of the synthesized compound is placed carefully in the aluminum pan and closed with
the lid The lid is crimped by a sample press and the pan is weighed The weight of the sample is
32
determined by removing the weight of the pan and lid For the determination of melting point
and heat capacity (20-25) mg of the sample was used
Perkin-Elmer Diamond Differential Scanning Calorimeter (DSC) is used to measure the
melting point and heat capacity of compound The crimped ample pan was immediately put
inside the sample chamber of DSC after preparation and held at 52315 K for 10 hours to remove
the trace amount of moisture possibly caught in the process of loading sample and also to ensure
a homogeneous mixture In the experimental procedure a temperature range from 29815 K to
52315 K was set with a heating rate of 5 K min
1 followed by a cooling cycle at the same rate
This cycle is repeated for at least 6 times to ensure good mixture of the sample and
reproducibility of the results
52 Heat Capacity determination of molten salt mixtures
To start Cp measurement the same procedure as that of melting point determination is
followed with an addition of bdquoiso-scan-iso‟ steps to the program after 5-cycle temperature scan
Starting from 29815 K the temperature was held for 5 minutes before and after each scan step
Small temperature scan range is chosen to avoid thermal resistance between device and testing
sample except when the temperature is approaching the melting temperature The upper limit for
the Cp measurement was set to 62315 K in our experiments Since the change in the molar heat
capacity of the salt in the liquid state is very small the Cp data in the liquid state can be easily fit
to an equation and extrapolated to higher temperatures To get the value of molar heat capacity
of the sample heat flow curve for the baseline of the empty sample pan also needs to be obtained
immediately following the identical ldquoiso-scan-isordquo steps which were used for the actual sample
33
run The difference of heat flow between the actual crimpled sample and the empty sample pan is
the absolute heat absorbed by the test sample
53 Density determination of molten salt mixtures
Density measurement was carried out with standard densitometer which has fixed volume
Initial weight of the densitometer is measured and noted Salt composition of which the density
is measured is placed in a beaker on a hot place The densitometer is also placed on the same hot
plate The temperature is set to a fixed value above the melting point of the salt and is measured
by a thermocouple After the salt is melted and when the temperature shows stable reading the
molten salt is poured in to the densitometer up to the set mark on the sensitometer bottle The
weight of the densitometer with the molten salt is measured The weight difference between this
weight and the weight of empty densitometer gives the weight of the molten salt at the fixed set
temperature By knowing the fixed volume in the densitometer the density of the salt at that
temperature can be calculated This procedure is repeated at least three times to accurately
determine the density of the salt
34
CHAPTER 6
RESULT AND DISCUSSION
61 Melting point determination
611 DSC equipment calibration
Before the actual melting point measurement pure indium zinc metal and several
individual salts were used to calibrate the DSC equipment For metals only one sharp peak was
observed for each and the heat flow curve for indium metal is shown in fig 61 However larger
and boarder peaks are found for salts just like the condition illustrated in fig 62 for pure
potassium nitrate Based on the results shown in Table 61 the experimental data for melting
points and enthalpies of fusion have excellent agreement with the literature values [60-63] The
variation of point is within 07 and the variation of change of enthalpy is less than 3
Figure 61 Melting point calibration with indium sample
35
Figure 62 Melting point calibration with KNO3 sample
Table 61 Calibration data of melting points with different samples
Sample
Lit
Tmp
Expt
Tmp
Lit
Ttrans
Expt
Ttrans
Lit
ΔHfusion
Expt
ΔHfusion
Lit
ΔHtrans
Expt
ΔHtrans
degC degC degC degC Jg Jg Jg Jg
Indium 1566 1563 - - 286 278 - -
Zinc 4195 4188 - - 1086 1068 - -
LiNO3 2567 2550 - - 3617 3633 - -
NaNO3 3100 3081 2770 2753 1777 1756 147 152
KNO3 3370 3372 1330 1332 993 1005 538 529
612 Results
Differential scanning calorimetry (DSC) was used to determine the melting point and any
solid state phase transitions of the salt mixture A low scanning rate was chosen to record the
heat flow curve as function of temperature in order to improve the sensitivity of detection [64] It
helps to pick up any small endothermic peaks and also avoids the thermal resistance between the
36
internal furnace and sample Nine systems were chosen to test and the eutectic composition is
already listed in Table 41
All the selected systems are composed of alkaline nitrate and nitrite and most of them have
three basic components which are lithium sodium potassium nitrate or nitrite All the quaternary
and quinary systems were developed on the basis of the LiNO3-NaNO3-KNO3 baseline ternary
Figure 63-611 shows the DSC plot of all the salt systems DSC plots for each system were
collected for at least five runs (each run with fresh salt preparation) to ensure the reproducibility
All the onset temperatures peak temperatures predicted temperatures enthalpy of fusion for
melting peaks and the solid phase transformation temperatures are given in Table62
Figure 63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt
37
Figure 64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt
Figure 65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt
38
Figure 66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt
Figure 67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt
39
Figure 68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
Figure 69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
40
Figure 610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt
Figure 611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN salt
Table 62 illustrates that the predicted melting point is close to the experimental
determined value and most deviation is within 10 except for system 9 The great agreement
41
between experimental and calculated data verifies the accuracy and feasibility of the
thermodynamic modeling
Table 62 DSC results of melting point transition point and predicted melting point
System Tmp Ttrans ΔHfusion
Calculated degC Onset degC Peak degC Peak degC Jg
Salt 1 1160 994 1191 1043 600
Salt 2 1238 1150 1240 NA 97
Salt 3 986 940 999 NA 244
Salt 4 986 940 1010 NA 60
Salt 5 957 910 950 NA 62
Salt 6 1000 930 960 NA 86
Salt 7 1081 992 1003 793 60
Salt 8 1008 1010 1019 853 59
Salt 9 1036 834 892 NA 93
613 Discussion
It is observed that the first curve is different from last ones shown in the DSC plots and
this phenomenon is common for all the melting point measurement with DSC technique This
happened because in the first cycle the moisture caught by salt mixture especially the lithium
nitrate was removed in the process of heating Moreover the partially solidified sample in the
sample loading process can be re-homogenized in the first heating cycle [65-67] In figure 63
69 and 610 more than one endothermic peak was found The first smaller endothermic peak
refers to solid state phase transition of the salt mixture The second larger endothermic peak
refers to the melting of the salt Normally the onset temperature of transition is taken as the
experimental transition point for any metallic sample However in case of molten salts mixtures
since the thermal conductivity is low [68-74] the complete transition is ensured only at the peak
42
transition temperature The thermal gradient which exists due to the low thermal conductivity of
the salt results in internal heat flow which enhances the mixing in the salt Thus the transition
temperature is defined as the peak temperature of phase transition For salt No1 the small
endothermic peak happened before and was connected to the main peak which occurred at
39027K The first endothermic peaks for salt No 7 and 8 occurred at almost the same
temperature because of the similar composition for these two compounds Since the small
amount of magnesium nitrate and potassium nitrite contained in these two compounds the small
endothermic peak can hardly be related to these two components Obviously the rest three major
components must have something to do with the first peaks happened before the melting peaks
for both cases Each component among the major three ones were tested to find out any possible
solid phase transition peaks of them and the results shown in Table 63 which reveals that
lithium nitrate doesnt have any phase transition peak in solid state while potassium nitrate and
sodium nitrite both own the solid phase transformation peaks before their melting peaks
Table 63 Fusion and solid phase transition temperature for individual salts
System Tmp degC Ttrans degC ΔHfusion Jg ΔHtrans Jg
LiNO3 2550 - 3633 -
KNO3 3372 1332 1005 529
NaNO2 4311 4170 1119 880
The further investigation was carried out by running the KNO3-NaNO2 (550 wt and 238 wt )
binary compound with the very similar weight percentage as that in salt No 7 (546 wt and
237 wt) and salt No 8 (559wt and 239wt) By converting the weight percentage of the
studied binary system into 100 scale the weight fraction for sodium nitrate and potassium
nitrate can be rewritten as 698wt and 302wt The DSC plot for this binary system was
43
shown in fig 612 Although the solid transition and melting temperature were brought down by
adding lithium nitrate the shape of the plots in fig 69 and 610 are identical to that shown in fig
612 The enthalpy of solid state transformation of the binary salt was also converted to that in
both quaternary systems by using the weight fraction occupied by the binary system and the
comparable change of converted enthalpy between the binary system and two quaternary systems
indicates the relevance of the solid transition peaks in salt 7 and 8 to the combined effect of
potassium nitrate and sodium nitrite
Figure 612 DSC plot of 698wt KNO3- 302wt NaNO2 binary system
The similar analysis was applied to No1 salt to find out the reason for the presence of a
small peak adherent to the main melting peak before the melting point Sodium nitrate and
potassium nitrate binary system was synthesized based on the weight fraction of these two
constituent salts in No 1 salt DSC plot for the sodium nitrate-potassium nitrate binary system in
Fig 613 with the converted composition which is essentially same as that in the No1 ternary
system shows smooth heat flow curve before the melting peak which means the solid transition
peak in ternary is not simply relative to the binary system Assumption was made that the solid
44
phase transformation peak in the ternary salt is resulted from a multiple effect ie the
combination of one of the eutectic binary system involved in the ternary salt mixture and the
other binary system which is composed of the rest components The statement is verified that the
small peak in salt 1 is mainly caused by the solid phase transformation peak in lithium nitrate-
potassium nitrate eutectic binary system given the similar shape of the DSC plots in Fig 614
Since in salt No1 there is excess amount of sodium nitrate to form the lithium nitrate-sodium
nitrate binary system the rest sodium nitrate can interact with potassium nitrate and form new
sodium-potassium nitrate system which is shown in fig615 Besides a solid phase
transformation peak is observed in fig615 which has a very small area and won‟t change the
shape of phase transformation peak in fig614 when these two binary systems are combined and
form salt 1 The enthalpies of solid state transformation in two binary salts were also converted
to that in salt 1 by using the weight fractions occupied by both binary systems The difference
of the change of converted enthalpies between the lithium-potassium nitrate eutectic binary and
ternary system is filled by the binary mixture which is composed of the rest components sodium
nitrate-potassium nitrate The comparable converted values of enthalpy change between salt 1
and its two constituent binary systems further verify the assumption that the solid phase
transformation happened in salt 1 is mainly due to the combined effect of LiNO3-KNO3 eutectic
binary system and NaNO3-KNO3 binary system
45
Figure613 DSC plot of 270wt NaNO3-730wt KNO3 binary system
Figure614 DSC plot of 458wtLiNO3-542wtKNO3 binary system
46
Figure615 DSC plot of 460wt NaNO3-540wt KNO3 binary system
Unlike those discussed mixtures above salt No2 Salt No4 Salt No5 and Salt No6 have
only one relatively board melting peak and the heat flow curve before and after are very stable
Similarly there is no solid transformation peaks observed in salt No3 salt No7 and salt No8
However the heat flow after the melting peak in these cases are not stable and the main
endothermic peak is followed by a small hump which is considered to be the recrystallization
process once the compound entered into the liquid state When the process is finished the heat
flow curve returns to steady state
Heating rate is a significant parameter when collect the heat flow curves by using DSC
technique Fig 616(a) and Fig 616(b) illustrate the difference of melting point for salt No6 due
to the change of heating rate If the heating rate is 20oCmin the peak temperature and onset
temperature for the melting peak is 9669oC and 9221
oC respectively Once the heating rate is
decreased to 5oCmin these two temperatures will also be lowered to 9614
oC and 9190
oC The
difference is resulted from the diverse amount of thermal resistance between the testing sample
and the furnace inside the DSC instrument [75] Under higher heating rate the decisive thermal
47
resistance is raised due to the low thermal conductivity medium between the furnace and the
actual sample The insensitivity of gas heat conduction medium in DSC results each unit of
temperature increase on one side cannot have an immediate response on the other side of the gas
Consequently the sample holder which is connected the furnace has a higher temperature than
that inside the sample In this condition the value of temperature profile collected as the sample
holder temperature is larger than the actual temperature The deviation will be much smaller
when the heating rate is reduced In the case the thermal resistance will be decreased because of
the lower temperature gradient of the gas medium in the heating process As a result of that the
collected temperature from the sensor attached to the sample holder will be very close to the
actual temperature inside the testing sample
Figure 616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 20oCmin
heating rate
48
Figure 616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 5oCmin
heating rate
Besides the difference of temperature while using higher and lower heat rate the solution
of DSC will also be affected by different heating rate Fig 617(a) shows the DSC plot for salt
No 7 using the heating rate as 5oCmin and the DSC plot in Fig 617(b) is collected under the
heating rate as 20oCmin It can be observed that in the lower heating rate two small separated
peaks can be viewed as two parts of the solid phase transformation process while in Fig 617(b)
two small peaks before the melting peak merge and present as a board hump The qualification
of resolution can be executed by the term named resolution factor RMKE which is calculated as
the ratio of the peak heat flow value of the separated peaks to that of the concave point between
two peaks The equation for determining RMIKE is given in Eq 27 [76 77]
RMIKE =hpeakhmin [27]
49
Figure 617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 5oCmin
heating rate
Figure 617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 20oCmin
heating rate
In the case of lower heating rate the RMKE is determined to be 15 and the value for higher
heating rate is not available because the concave point of heat flow doesn‟t exist from
Fig617(b) Since the higher RMKE value indicates better resolution it can be stated that the
50
lower heating rate also results in greater sensitivity of the equipment to pick up any small
endothermic peaks
Besides the down-selected 9 compounds some more salt mixtures were also tested Most
of them were not selected to the final candidate for the thermal energy storage application
because of their higher melting point Table 64 gives some of the trial systems measured with
DSC technique It is illustrated that the melting points of mixtures with lower or even no content
of lithium nitrate turn out to be higher than those with sufficient amount of lithium nitrate For
most of the mixtures with melting point lower than 120oC the amount of lithium nitrate should
be larger than 81wt Also all of the systems in table 64 with lithium nitrate less than 15wt
have melting point higher than 140oC Based on the observation above it is concluded that the
lithium nitrate can be used as an additive to bring the melting point down for thermal energy
storage systems
51
Table 64 Melting points of candidate systems as function of temperatures
System Composition (wt)
Onset
Temp
Peak
Temp
(oC) (
oC)
LiNO3 ndash NaNO3 ndash KNO2 107 459 434 890 910
LiNO3 - KNO3 - NaNO2 196 564 241
1024 1046
LiNO3 - NaNO3 - KNO3 - KNO2 90 423 337 151
930 960
LiNO3 - NaNO3 - NaNO2 - KNO2 81 454 65 401
900 910
LiNO3 - KNO3 - NaNO2 - KNO2 193 546 237 24
992 1003
LiNO3 - KNO3 - NaNO2 ndash Mg(NO3)2 193 559 238 09
1010 1020
LiNO3 - NaNO3 - KNO3 - Mg(NO3)2
- MgK 154 172 324 83 267 834 892
LiNO3 - NaNO3 - KNO2 ndash Ca(NO3)2 14 390 333 263
1250 1470
NaNO3 - KNO3 - NaNO2 - KNO2 425 163 71 341
1407 1447
NaNO3 - KNO3 - KNO2 ndash Mg(NO3)2 432 146 380 42
1386 1421
NaNO3 - NaNO2 - KNO2 - Ca(NO3)2 451 92 410 48
1150 1390
LiNO3 - NaNO3 - NaNO2 - KNO2 -
Ca(NO3)2 15 393 37 323 232 1380 1480
LiNO3 - NaNO3 - KNO2 - Ca(NO3)2 -
Mg(NO3)2 14 379 313 275 20 1339 1534
62 Heat capacity determination
621 Heat capacity calibration
DSC was also calibrated for the heat capacity measurement Lithium nitrate sodium
nitrate and potassium nitrate were examined for the heat capacities from room temperature to
upper limit temperature for the instrument In liquid state the heat capacity values for each salt
can be fit to straight line with trace amount of increasing trend Since the temperature range from
the onset temperature of liquid state to the upper limit of DSC is relatively small the heat
capacity values for pure individual salts can be viewed as constants The comparison between the
theoretical and experimental heat capacity data is given in Table 65 Except lithium nitrate the
52
experimental heat capacities data for the rest two systems are almost same as the literature Even
for lithium nitrate which demonstrates the biggest difference from the literature data the 28
vibration is still within a reasonable range
Table 65 Calibration data of heat capacities with different samples
Sample Lit Cp Expt Cp
JgK JgK
LiNO3 218 212
NaNO3 169 167
KNO3 140 139
622 Results
The materials used in the heat capacity measurements are the same as those in the melting
point experiments Molar heat capacities of the all compound were measured by the DSC
equipment from room temperature to 62315 K The heat flow is recorded as a function of
temperature in ldquoiso-scan-isordquo steps at intervals of 20 K The bdquoiso stage‟ refers to isothermal
holding at a particular temperature bdquoscan stage‟ refers to the heat flow recording at a heating rate
of 5 K min1
up to a an increment of 25 K followed by another isothermal holding stage This is
a standard procedure followed in the measurement of heat capacity of materials using the DSC
equipment [63 64] This procedure of heat capacity measurement has two advantages (i) any
heat fluctuations during the recording are avoided by the isothermal steps and (ii) any phase
transition can be highlighted by the choice of temperature range The absolute heat flow to the
sample is determined by subtracting the heat flow collected by running a baseline curve with an
empty pan Because the heat capacity measurement in the heating process corresponds to
53
collecting the value of required heat flow at each temperature all the heat capacity plots have the
same shape with that of heat flow in the melting point measurements Take the heat capacity plot
of LiNO3-NaNO3-KNO3 ternary system as an instance which is shown in fig 618 the heat
capacity curve also has two different peaks The first little peaks corresponds to one occurs at
39027K which was observed in fig 63 the second large and sharp peak happened right after the
small one is prevalent to the endothermic peak with the peak temperature as 39027 K Similarly
after the phase transformation the heat capacity in liquid state becomes very stable and increase
with temperature linearly with little slope
Fig 618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system as function of
temperature
The heat capacity change as function of temperature for salt No1 was illustrated in fig
619 Based on the trend of heat capacity in the liquid state any value for the system in the liquid
can be extrapolated The expressions for heat capacity in liquid state for the new molten salt
systems were discussed and given in the next sectionTable66 shows the specific heat capacity
54
of the all the selective compounds measured at 62315 K and extrapolated at 77315K Besides
the molar heat capacities at 77315K are given in Table 66 of all the salts
Fig 619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K
Table 66 Heat capacity of selected new TES molten salt mixtures
System Expt (62315K) Extrapolated(77315K) Extrapolated(77315K)
Cp JgK Cp JgK Molar Cp JmolK
Salt 1 153 170 1521
Salt 2 143 168 1515
Salt 3 148 155 2183
Salt 4 153 166 1411
Salt 5 153 170 1440
Salt 6 151 163 1435
Salt 7 156 167 1443
Salt 8 155 168 1410
Salt 9 161 170 1937
55
623 Thermodynamic properties
The standard thermodynamic properties such as entropy enthalpy and Gibbs energy for
salt mixtures are determined from the experimental data of melting point and heat capacity in the
temperature range of the present study and expression for determining these properties are given
in equation 28-30 In thermodynamics all these three properties are related to heat capacity and
its variances with temperature In the studied temperature range (29815K-62315K) they can be
described as expression includes heat capacity
[28]
[29]
[30]
Where Tt is the solid transformation temperature Tmp is the melting point ΔHt is enthalpy of
solid phase transformation and ΔHfusion is enthalpy of fusion The standard thermodynamic
properties entropy enthalpy and Gibbs energies as function of temperature for each compound
are expressed in the following section
6231 LiNO3-NaNO3-KNO3 (Salt 1)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3
compound (i) solid state 1 (32315-38415) K (ii) liquid state (40315-62315) K Accordingly
56
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62311 Heat capacity of solid state 1 (29815-38415) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the solid state 1 in the
temperature range of 29815 to 38415 K is fit to a second order polynomial equation Eqn (31)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[31]
( ) K
R2 = 0982
62312 Heat capacity of liquid state (40315-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a linear equation Eqn (32) gives the linear
equation along with the least square fit parameter (R2) in the temperature range for the liquid
state of the compound
JKmol [32]
57
R2 = 0947
Heat capacity data of the LiNO3-NaNO3-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62313 Thermodynamic properties of solid state 1(29815-38415) K
JKmol [33]
Jmol [34]
[35]
Jmol
62314 Thermodynamic properties of liquid state 2(40315-62315) K
[36]
58
JKmol
Jmol [37]
[38]
Jmol
Among the equations above equation (33)-(35) refer to the thermodynamic properties for
solid state equations (36)-(38) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature ranges for solid and liquid state are
given in Table A1 and A2 in appendix A respectively with the corresponding heat capacity as
function of temperature
6232 NaNO3-NaNO2-KNO3 (Salt 2)
The heat capacity data can be divided into two sections for NaNO3-NaNO2-KNO3
compound (i) solid state 1 (32315-39215) K (ii) liquid state (41315-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62321 Heat capacity of solid state 1 (29815-39215) K
59
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the solid state in the
temperature range of 29815 to 39215 K is fit to a second order polynomial equation Eqn (39)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[39]
( ) K
R2 = 0978
62322 Heat capacity of liquid state (40315-62315) K
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a second order polynomial equation Eqn (40)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[40]
R2 = 0941
60
Heat capacity data of the NaNO3-NaNO2-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62323 Thermodynamic properties of solid state 1(29815-39215) K
JKmol [41]
Jmol [42]
[43]
Jmol
62324 Thermodynamic properties of liquid state 2(40315-62315) K
JKmol [44]
61
Jmol [45]
[46]
Jmol
Among the equations above equation (41)-(43) refer to the thermodynamic properties for
solid state equations (44)-(46) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table B1 and B2 in appendix B respectively with the corresponding heat capacity as
function of temperature
6233 LiNO3-NaNO3 -KNO3-MgK (Salt 3)
The heat capacity data can be divided into two sections for LiNO3-NaNO3 -KNO3-MgK
compound (i) solid state 1 (29815-36415) K (ii) liquid state (42115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62331 Heat capacity of solid state 1 (29815-36415) K
62
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the solid state in the
temperature range of 29815 to 36415 K is fit to a second order polynomial equation Eqn (47)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[47]
( ) K
R2 = 0995
62332 Heat capacity of liquid state (42115-62315) K
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the liquid state in the
temperature range of 42115 to 62315 K is fit to a second order polynomial equation Eqn (48)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[48]
R2 = 0963
63
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
62333 Thermodynamic properties of solid state 1(29815-36415) K
JKmol [49]
Jmol [50]
[51]
Jmol
62334 Thermodynamic properties of liquid state 2(42115-62315) K
64
JKmol [52]
Jmol [53]
[54] [29]
Jmol
Among the equations above equation (49)-(51) refer to the thermodynamic properties for
solid state equations (52)-(54) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table C1and C2 in appendix C respectively with the corresponding heat capacity as
function of temperature
6234 LiNO3-NaNO3-KNO3-NaNO2 (Salt 4)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-NaNO2
compound (i) solid state 1 (29815-36315) K (ii) liquid state (38115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62341 Heat capacity of solid state 1 (29815-36315) K
65
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the solid state in the
temperature range of 29815 to 36315 K is fit to a second order polynomial equation Eqn (55)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[55]
( ) K
R2 = 0995
62342 Heat capacity of liquid state (38115-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the liquid state in the
temperature range of 38115 to 62315 K is fit to a second order polynomial equation Eqn (56)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[56]
R2 = 0972
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
66
62343 Thermodynamic properties of solid state 1(29815-36315) K
JKmol [57]
Jmol [58]
[59]
Jmol
62344 Thermodynamic properties of liquid state 2(38115-62315) K
JKmol [60]
Jmol [61]
67
[37]
Jmol [62]
Among the equations above equation (57)-(59) refer to the thermodynamic properties for
solid state equations (60)-(62) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table D1 and D2 in appendix D respectively with the corresponding heat capacity as
function of temperature
6235 LiNO3-NaNO3-NaNO2-KNO3-KNO2 (Salt 5)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-NaNO2-KNO3-
KNO2 compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62351 Heat capacity of solid state 1 (29815-35915) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
in the temperature range of 29815 to 35915 K is fit to a second order polynomial equation Eqn
(63) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
68
[63]
( ) K
R2 = 0996
62352 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the liquid
state in the temperature range of 37515 to 62315 K is fit to a second order polynomial equation
Eqn (64) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[64]
R2 = 0969
Heat capacity data of the LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62353 Thermodynamic properties of Solid state 1(29815-35915) K
JKmol [65]
69
Jmol [66]
[67]
Jmol
62354 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [68]
Jmol [69]
[45]
Jmol [70]
70
Among the equations above equation (65)-(67) refer to the thermodynamic properties for
solid state equations (68)-(70) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table E1 and E2 in appendix E respectively with the corresponding heat capacity as
function of temperature
6236 LiNO3-NaNO3-KNO3-KNO2 (Salt 6)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-KNO2
compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62361 Heat capacity of solid state 1 (29815-36515) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the solid state in the
temperature range of 29815 to 36515 K is fit to a second order polynomial equation Eqn (71)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[71]
( ) K
R2 = 0998
71
62362 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the liquid state in the
temperature range of 37515 to 62315 K is given in Table 20 The data is fit to a second order
polynomial equation Eqn (72) gives the linear equation along with the least square fit parameter
(R2) in the temperature range for the liquid state of the compound
[72]
R2 = 0953
Heat capacity data of the LiNO3-NaNO3-KNO3-KNO2 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62363 Thermodynamic properties of solid state 1(29815-35915) K
JKmol [73]
Jmol [74]
72
[75]
Jmol
62364 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [76]
Jmol [77]
Jmol [78]
Among the equations above equation (73)-(75) refer to the thermodynamic properties for
solid state equations (76)-(78) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
73
given in Table F1 and F2 in appendix F respectively with the corresponding heat capacity as
function of temperature
6237 LiNO3-KNO3-NaNO2-KNO2 (Salt 7)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62371 Heat capacity of solid state 1 (29815-35415) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 1 in
the temperature range of 29815 to 35415 K is fit to a second order polynomial equation Eqn
(79) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[79]
(29815-35415) K
R2 = 0993
62372 Heat capacity of solid state 2 (36215-37315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 2 in
the temperature range of 36215 to 37315 K is fit to a second order polynomial equation Eqn
74
(80) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 2 of the compound
[80]
R2 = 0977
62373 Heat capacity of liquid state (37915-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the liquid state in the
temperature range of 37915 to 62315 K is fit to a linear equation Eqn (81) gives the
polynomial equation along with the least square fit parameter (R2) in the temperature range for
the liquid state of the compound
[81]
R2 = 0961
Heat capacity data of the LiNO3-KNO3-NaNO2-KNO2 compound in the two solid states
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62374 Thermodynamic properties of solid state 1(29815-35415) K
75
JKmol [82]
Jmol [83]
[84]
Jmol
62375 Thermodynamic properties of solid state 2(36215-37315) K
JKmol [85]
Jmol [86]
76
[87] [62]
Jmol
62376 Thermodynamic properties of liquid state (37915-62315) K
JKmol [88]
Jmol [89]
Jmol [90]
Among the equations above equation (82)-(84) refer to the thermodynamic properties for
solid 1 equation (85)-(87) refer to the thermodynamic properties for solid 2 equations (88)-(90)
refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy values
77
in the studied temperature range for solid 1 solid 2 and liquid state are given in Table G1-G3 in
appendix G respectively with the corresponding heat capacity as function of temperature
6238 LiNO3-KNO3-NaNO2-Mg(NO3)2 (salt 8)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62381 Heat capacity of solid state 1 (29815-33715) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid
state 1 in the temperature range of 29815 to 33715 K is fit to a second order polynomial
equation Eqn (91) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the solid state 1 of the compound
[91]
(29815-33715) K
R2 = 0994
62382 Heat capacity of solid state 2 (36115-36415) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid state 2
in the temperature range of 36115 to 36415 K is given in Table 4 The data is fit to a second
78
order polynomial equation Eqn (92) gives the polynomial equation along with the least square
fit parameter (R2) in the temperature range for the solid state 2 of the compound
[92]
R2 = 0992
62383 Heat capacity of liquid state (41115-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the liquid state in
the temperature range of 41115 to 62315 K is given in Table 5 The data is fit to a linear
equation Eqn (93) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the liquid state of the compound
[93]
R2 = 0934
Heat capacity data of the LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the two solid
states follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62384 Solid state 1(29815-35415) K
79
JKmol [94]
Jmol [95]
[96]
Jmol
62385 Solid state 2(36115-36415) K
JKmol [97]
80
Jmol [98]
[99] [74]
Jmol
62386 Liquid state (41115-62315) K
JKmol [100]
Jmol [101]
Jmol [102]
Among the equations above equation (94)-(96) refer to the thermodynamic properties for
solid 1 equation (97)-(99) refer to the thermodynamic properties for solid 2 equations (100)-
(102) refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy
81
values in the studied temperature range for solid 1 solid 2 and liquid state are given in Table H1
and H2 in appendix H respectively with the corresponding heat capacity as function of
temperature
6239 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK(Salt 9)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-
Mg(NO3)2-MgK compound (i) solid state 1 (29815-35315) K (ii) liquid state (39115-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62391 Heat capacity of solid state 1 (29815-35315) K
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state in the temperature range of 29815 to 35315 K is fit to a second order polynomial equation
Eqn (103) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[103]
( ) K
R2 = 0996
62392 Heat capacity of liquid state (39115-62315) K
82
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the liquid
state in the temperature range of 39115 to 62315 K is fit to a second order polynomial equation
Eqn (104) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[104]
R2 = 0951
Heat capacity data of the LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62393 Solid state 1(29815-35315) K
JKmol [105]
Jmol [106]
83
[107]
Jmol
62394 Liquid state 2(39115-62315) K
JKmol [108]
Jmol [109]
[110]
Jmol
Among the equations above equation (105)-(107) refer to the thermodynamic properties
for solid state equations (108)-(110) refer to thermodynamic properties of the liquid The
entropy enthalpy and Gibbs energy values in the studied temperature range for solid and liquid
state are given in Table I1 and I2 in appendix I respectively with the corresponding heat
capacity as function of temperature
84
624 Discussion of Gibbs energy change for molten salts
The Gibbs energy change data as function of temperature for 9 systems are given in fig
620 and the values at 62315K are shown in Table 67 Every system demonstrates continuous
curve throughout the whole studied temperature range Most of systems have similar Gibbs
energy change values for each temperature spot due to the comparable compositions and
properties of constituent salts However salt 3 and salt 9 Both of these salts have certain
amount of MgKN compound which presents large absolute amount of change of Gibbs energy in
the same studied temperature range [66] Since the change of Gibbs energy for multi-component
mixture is relevant to that of each constituent salt the large absolute value of ΔG of MgKN
mainly contributes to the largely negative value of salt 3 and salt 9 shown in fig 620 Besides
it is observed that most systems contain nitrite salts present lower absolute value of Gibbs energy
change For example salt 1 doesn‟t include any nitrite salt and has a relatively high absolute
value of Gibbs energy change as 1704kJmol while other systems having nitrite salts show lower
value varies from 1372kJmol to 1592kJmol
85
Fig 620 Change of Gibbs energy as function of temperature for molten salt systems
Table 67 Change of Gibbs energy values at 62315K for molten salt systems
SNo System ΔG(kJmol)
1 LiNO3-NaNO3-KNO3 1704
2 NaNO3- NaNO2- KNO3 1372
3 LiNO3- NaNO3- KNO3- MgKN 2807
4 LiNO3- NaNO3- KNO3- NaNO2 1443
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1441
6 LiNO3-NaNO3-KNO3-KNO2 1570
7 LiNO3-KNO3-NaNO2-KNO2 1592
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1583
9 LiNO3-NaNO3-KNO3-Mg(NO3)2 -MgKN 2217
86
63 Density determination
631 Density calibration
Several pure molten salts are used to calibrate the density measurement set-up before the
actual density measurement All the density values decrease as function of temperature in the
liquid state and follow the same linear equations as described in eq 4 The experimental values
at 350oC for KNO3 NaNO3 and LiNO3 are selected to compare with the literature data at the
same temperature The results are shown in Table 68 Based on the comparison of the literature
data and the experimental data the variation of density for molten nitrate salt is within in 4
Table 68 Calibration of density measurements with different pure nitrate salts
Sample Literature density Experimental density
gcm3 gcm
3
LiNO3 1727 1701
NaNO3 2066 2144
KNO3 1860 1855
632 Results and discussions
The density result of the salt as function of temperature is plotted for all the salts in Figure
621 and Figure 622 It is observed that the temperature dependence of density above the
melting point is different from that in solid state As known in solid state the density of salt has
an exponential relation with temperature while in these liquid cases the density values have
linearly dependence with temperature The stable variation as function of temperature allows the
extrapolation of density at even higher temperature The regression analysis is performed to get
the coefficient used for describing eq 4 and the results for the coefficients are shown in
87
Table69 [78-80] It is observed that the change of composition is implied on the coefficient A
which indicates the initial point at 150oC The temperature dependence coefficient B doesn‟t
change much with composition which may be mainly affected by the group of anion and cation
Table 69 Coefficient A and B for density determination of salt 1-salt 9
Salt No System A Btimes10
3
(gcm3) (gcm
3degC)
1 LiNO3-NaNO3-KNO3 2032 0493
2 NaNO3- NaNO2- KNO3 2081 0570
3 LiNO3- NaNO3- KNO3-MgKN 2055 0526
4 LiNO3- NaNO3- KNO3- NaNO2 2033 0520
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 2018 0485
6 LiNO3-NaNO3-KNO3-KNO2 2060 0554
7 LiNO3-KNO3-NaNO2-KNO2 2048 0554
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 2044 0524
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 2060 0566
Figure 621 The densities of the salt 1-salt 5 as function of temperature
88
In figure 621 all the density values are clustered around 198gcm3 at 150
oC to
186gcm3 at high temperature end and the deviation of density between all the mixtures is within
in 0047g cm3 Among all the salt mixtures the NaNO3-NaNO2-KNO3 ternary system
demonstrates the highest density value throughout the studied temperature range and LiNO3-
NaNO3-KNO3 ternary system LiNO3- NaNO3-KNO3-NaNO2 quaternary system and LiNO3-
NaNO3-KNO3-NaNO2-KNO2 quinary system show densities at the bottom side of Fig 621 For
salt 2 which doesn‟t contain any lithium nitrate the density at every selected temperature spot
is obviously higher than that of salt 1 4 and 5 which have large amount of lithium nitrate
Moreover the salt 3 which contains the relatively small amount of lithium nitrate stays in
between of salt 1 and salt 2 This comparison illustrates that the addition of lithium nitrate has
an offsetting effect on density for molten salt and it is consistent with previous literature reports
[81] The four systems presented in figure 622 also show even closer density values in the
studied temperature range Similarly salt 6 which contains the least lithium nitrate has the
largest density Salt 7 and salt 8 have almost same composition for the three dominating
components as a result of that the density curves for both mixtures are determined by the same
regression coefficient A and B Moreover the larger amount of lithium nitrate involved in these
two salt mixtures contributes to the lower density given in figure622 which further verifies the
significantly offsetting effect of lithium nitrate on density
89
Figure 622 The densities of the salt 6-salt 9 as function of temperature
The salt mixtures with maximum and minimum amount of lithium nitrate were plotted and
compared with equimolar NaNO3-KNO3 binary system and pure KNO3 salt in Fig623 [82 83]
It is observed that the NaNO3-KNO3 binary system has very similar density value to that of salt
2 because of the analogous type and composition of component in both salts The density of
pure KNO3 is slightly lower than the binary salt mixture which indicates the density of NaNO3 is
close to but higher than KNO3 in the studied temperature range Salt 1 shows the lowest density
in Fig623 due to the offsetting effect on density caused by lithium nitrate which has been
discussed above
90
Figure 623 Density of the salt 1 salt 2 as function of temperature compared to the
equimolar NaNO3-KNO3 binary system and pure KNO3
64 Thermal energy storage density of molten salts
The energy density which is considered as one of the most significant parameters of TES
application can be evaluated by calculation based on the measured density heat capacity and
working temperature range The equation of the thermal energy storage density (E) at working
temperature of 500oC is expressed in equation 111
E = Cp (500-Tm) [111]
Where Cp and are extrapolated heat capacity and density at 500oC respectively Tm is
melting point for salt mixture The extrapolation of density and heat capacity is based on the
linear temperature dependence for both parameters in molten state and the values are shown in
Table 610
91
Table 610 Extrapolated value of density and heat capacity at 500oC of salt 1-salt 9
Salt
No System
Density Heat Capacity
(gmL) (JgK)
1 LiNO3-NaNO3-KNO3 1785 170
2 NaNO3- NaNO2- KNO3 1796 168
3 LiNO3-NaNO3-KNO3-MgK 1773 155
4 LiNO3- NaNO3- KNO3- NaNO2 1792 166
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1796 170
6 LiNO3-NaNO3-KNO3-KNO2 1783 163
7 LiNO3-KNO3-NaNO2-KNO2 1771 167
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1782 168
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 1777 170
The calculated energy density for each salt is given in Table 611 compared with that of
solar salt (NaNO3-KNO3) All the new synthesized salt mixtures have significantly higher energy
density than solar salt and salt 3 shows the highest energy density among the new salts
Although salt 1 has higher heat capacity and good melting point the energy density is still the
lowest among new salt mixtures given by the effect of low density The conclusion can be drawn
from these observations that the energy density is a property affected by multiple parameters and
every part plays an important role in determining the efficiency of energy storage of salt
mixtures
92
Table 611 Energy density of salt 1-salt 9 compare to solar salt
The gravimetric storage density of new molten salts are listed in Table 612 and compared
with those different storage systems in fig 624 It is found that in the parabolic trough working
temperature range the gravimetric storage densities of new molten salts are located on the higher
side Even though some reported sensible energy storage liquids have larger gravimetric density
values than the new salts the maximum working temperatures reveal the instable working
condition at 500oC Taking conversion efficiency thermal stability and gravimetric storage
density into considerations the new molten salts are the most suitable choices of the sensible
heat storage for parabolic trough application
Salt No System Energy Density
500degC (MJm3)
0 NaNO3- KNO3 756
1 LiNO3-NaNO3-KNO3 1162
2 NaNO3- NaNO2- KNO3 1135
3 LiNO3-NaNO
3-KNO
3-MgKN 1099
4 LiNO3- NaNO
3- KNO
3- NaNO
2 1189
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1232
6 LiNO3-NaNO3-KNO3-KNO2 1174
7 LiNO3-KNO3-NaNO2-KNO2 1183
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1192
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 1242
93
Fig 624 Gravimetric storage density comparison of different energy storage systems as
function of temperature
Table 612 Gravimetric storage densities for solar salt and new molten salts
Salt
No System
Gravimetric Storage Density
500degC (kJkg)
0 NaNO3- KNO3 404
1 LiNO3-NaNO3-KNO3 560
2 NaNO3- NaNO2- KNO3 533
3 LiNO3-NaNO
3-KNO
3-MgKN 575
4 LiNO3- NaNO
3- KNO
3- NaNO
2 612
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 595
6 LiNO3-NaNO3-KNO3-KNO2 594
7 LiNO3-KNO3-NaNO2-KNO2 604
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 610
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 649
94
CHAPTER 7
CONCLUSION
The melting points of new molten salts were experimentally determined using DSC
Different from metals the melting point was chosen as the peak temperature rather than onset
temperature of the endothermic peak due to the low thermal conductivity and broad phase
transition range of the molten nitride salt mixture All of the nine new molten salts have melting
points from 89oC to 124
oC which are much lower than current sodium-potassium binary solar
salt Some systems such as salt No1 No7 and No8 have solid phase transformation observed
from the DSC plots It is found that the phase transformations of salt No 7 and No 8 are mainly
contributed to the KNO3-NaNO2 binary system while the small solid transformation peak of salt
No1 is resulted from the combined effect of the KNO3-LiNO3 eutectic binary system involved in
the ternary salt and another binary system which is composed of the rest components The
heating rate of DSC was revealed as a significant parameter for the any endothermic peak
determination When using lower heating rate the thermal resistance between the studied sample
and the furnace will be minimal and the resolution of peak detection will be enhanced
The heat capacities of all the multi-component salts (1 to 9) were determined using DSC
and found varying from 143 to 161 JgK at 350oC The heat capacity in the liquid state
demonstrates linear increase trend as function of temperature On the basis of that the heat
capacity was extrapolated to parabolic trough operating temperature of 500oC Besides heat
capacity data as function of temperature are fit to polynomial equation and thermodynamic
95
properties like enthalpy entropy and Gibbs energies of the compound as function of temperature
are subsequently deduced
Experimental measurements of density of multi-component systems were conducted as
function of temperature in their liquid state In liquid state the density values decrease linearly
as temperature increases The results of those mixtures were compared to the solar salt and
individual constituent salts The comparison demonstrates that the addition of lithium nitrate
lowers the density which is consistent with the observation that lithium nitrate has the lowest
density among all the individual salts in the studied temperature range On the basis of densities
heat capacities and the melting points energy storage density for all the new salts were
calculated and compared to the binary solar salt Among all the new molten salt systems
LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN quinary system (salt 9) presents the largest thermal
energy storage density as well as the gravimetric density values Moreover the larger thermal
energy storage as well as gravimetric storage densities compared to the solar salt indicate the
better energy storage capacities of new salts for solar power generation systems
96
REFERENCES
[1] JF Manwell JG McGowan and AL Rogers Wind Energy Explained-Theory Design and
Application second edition John Wiley and sons Ltd UK 2009
[2] MJ Pasqualetti Morality space and the power of wind-energy landscapes Geographical
Review 90 2000 381-394
[3] DG Fink and HW Beaty Standard Handbook for Electrical Engineers Eleventh Edition
McGraw-Hill New York 1978
[4] R Bertani Geothermal Energy An Overview on Resources and Potential Proceedings of the
International Conference on National Development of Geothermal Energy Use 2009 Slovakia
[5] TA Volk LP Abrahamson EH White E Neuhauser E Gray C Demeter C Lindsey J
Jarnefeld DJ Aneshansley R Pellerin and S Edick Developing a Willow Biomass Crop
Enterprise for Bioenergy and Bioproducts in the United States Proceedings of Bioenergy
2000 October 15-19 2000 Buffalo New York USA
[6] M Asplund N Grevesse and AJ Sauval The new solar abundances-Part I the
observations Communications in Asteroseismology 147 2006 76-79
[7] DRWilliams Sun Fact Sheet NASA 2004
httpnssdcgsfcnasagovplanetaryfactsheetsunfacthtml
[8] U Herrmann Survey of Thermal Energy Storage for Parabolic Trough Power Plants Journal
of Solar Energy Engineering 124 2002 145-152
[9] Rocket Research Company Chemical energy storage for solar thermal conversion SAND79-
8198 Livermore Sandia National Laboratories 1979
97
[10] A Steinfeld and R Palumbo Solar thermochemical process technology Encyclopedia of
Physical Science and Technology 2001 237-256
[11] EA Fletcher Solar thermal processing a review Journal of Solar Energy Engineering
2001 63-74
[12] R W Bradshaw and Nathan P Siegel Molten Nitrate Salt Development for Thermal
Energy Storage in Parabolic Trough Solar Power Systems of the Energy Sustainability 2008
Conference August 10-14 2008 Jacksonville Florida USA
[13] B Kelly H Price D Brosseau and D Kearney Adopting NitrateNitrite Salt Mixtures as
the Heat Transport Fluid in Parabolic Trough Power Plants Proceedings of the Energy
Sustainability 2007 Conference June 27-30 2007 Long Beach CA
[14] H Reilly and G Kolb Evaluation of Molten Salt Power Tower Technology Based on
Experience at Solar Two SAND2001-3674 Sandia National Laboratories 2001
[15] T Wendelin ldquoParabolic Trough VSHOT Optical Characterization in 2005-2006rdquo NREL
wwwnrelgovdocsfy06osti40024pdf
[16] RB Diver C Andraka S Rawlinson V Goldberg and G Thomas The Advanced Dish
Development System Project ASME Proceedings of Solar Forum 2001 Washington DC
[17] S D Odeh G L Morrison and M Behnia Modelling of parabolic trough direct steam
generation solar collectors Solar Energy 62 1998 396-406
[18] V Heinzel H Kungle and M Simon Simulation of a parabolic trough collector ISES
Solar World Congress Harare Zimbabwe 1-10
[19] S D Odeh G L Morrison and M Behnia Modeling of Parabolic Trough Direct
Generation Solar Collectors Solar Energy 62 1998 395-406
[20] Ezzat Optimum Working Fluids for Solar Powered Rankine Cycle Cooling of Buildings
Solar energy 25 1980 235-241
98
[21] R G Reddy Ionic Liquids How well do we know them editorial Journal of Phase
Equilibria and Diffusion 27 2006 210-211
[22] M Zhang and R G Reddy Application of [C4min][Tf2N] Ionic Liquid as Thermal
Storage and Heat Transfer Fluids editor J Weidner ECS Transactions 2 (28) 2007 27-32
[23] M Zhang and R G Reddy Evaluation of Ionic Liquids as Heat Transfer Materials in
Thermal Storage Systems Energy Energy Materials editors F Dogan M Awano D Singh
and B Tuttle ASM International Materials Park Ohio USA MSampT‟07 2007 151-160
[24] R G Reddy Novel Applications of Ionic Liquids in Materials Processing Advanced
Structural and Functional Materials Design 2008 Journal of Physics Conference Series (JPCS)
165 2009 1-6
[25] RW Bradshaw and DE Meeker High-temperature stability of ternary nitrate molten
salts for solar thermal energy systems Solar Energy Materials 21 1990 51-60
[26] AS Trunin Designing and investigations of salt systems for solar energy utilization
Utilization of sun and other radiation sources in materials research Kiev Naukova Dumka 1983
p 228-38
[27] D J Rogers and G J Janz Melting-crystallization and premelting properties of sodium
nitrate-potassium nitrate Enthalpies and heat capacities Journal of Chemical and Engineering
Data 27 1982 424-428
[28] D Kearney U Herrmann P Nava and B Kelly Assessment of a molten salt heat transfer
fluid in a parabolic trough solar field Journal of Solar Energy Engineering 125 2003 170-176
[29] Q Peng J Ding X Wei J Yang and X Yang The preparation and properties of multi-
component molten salts Applied Energy 87 2010 2812-2817
[30] E M Levin C R Robbins and H F McMordie Phase Diagrams for Ceramists American
Ceramic Society 1964
[31] J C Oxley J L Smith E Rogers and M Yu Ammonium nitrate thermal stability and
explosivity modifiers Thermochimica Acta 384 2002 23-45
99
[32] LG Marianowski and HC Maru Latent heat thermal energy storage systems above
4508oC Proceedings of 12th intersociety energy conversion engineering conference 1977 55-
66
[33] HC Maru JF Dullea A Kardas L Paul LG Marianowski E Ong et al Molten salts
energy storage systems Chicago Final Report of the Institute of Gas Technology 1978
[34] WM Philips and JW Stears Advanced latent heat of fusion thermal energy storage for
solar power stations Proceedings of 20th intersociety energy conversion engineering conference
2 1985 384-391
[35] KE Mayo Heat source systems USA Patent 3605720 1971
[36] JI Eichelberger and HD Gillman Investigation of metal fluoride thermal energy storage
material Proceedings of 12th intersociety energy conversion engineering conference 1977 567-
574
[37] GR Heidenreich and MB Parekh Thermal energy storage for organic Rankine cycle solar
dynamic space power systems Proceedings of 21st intersociety energy conversion engineering
conference 2 1986 791-797
[38] IK Garkushin AC Trunin TT Miftakhov and MA Dibirov Salt heat storage
composition USSR Patent 1036734 1983
[39] W M Philips and J W Stears Advanced latent heat of fusion thermal energy storage for
solar power stations In Proceedings of 20th intersociety energy conversion engineering
conference 2 1985 384-391
[40] Y Takahashi M Kamimoto Y Abe R Sakamoto K Kanari and T Ozawa Investigation
of latent heat-thermal energy storage materials IV Thermoanalitical evaluation of binary eutectic
mixtures of NaOH with LiOH or KOH Thermochim Acta 121 1987 193-202
[41] C E Birchenall and A F Riechman Heat storage in eutectic alloys Metall Trans A
11A(8) 1980 1415-1420
100
[42] Y Takahashi R Sakamoto and M Kamimoto Heat capacities and latent heats of LiNO3
NaNO3 and KNO3 International Journal of Thermophysics 9(6) 1988 1081-1090
[43] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate Mixtures
Journal of Chemical Engineering Data 8(3) 1963 469
[44] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical Engineering Data 6 (4) 1961 493
[45] GF Petersen WA Ewing and G P Smith Densities of Some Salt Mixtures Journal of
Chemical Engineering Data 6 (4) 1961 540
[46] G J Janz and M R Lorenz Precise Measurement of Density and Surface Tension at
Temperatures up to 1000degC in One Apparatus Review of Scientific Instruments 31 (1) 1960
18-23
[47] G J Janz C B Allen N P Bansal R M Murphy and R P Tomkins Physical Properties
Data Compilations Relevant to Energy Storage II Molten Salts Data on Single and Multi-
Component Salt Systems National Bureau of Standards NSRDS-NBS 61 Part II April 1979
[48] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation Equations
for Critically Evaluated Density Surface Tension Electrical Conductance and Viscosity Data
Journal of Physical and Chemical Reference Data 17 1988 2
[49] A T Ward and G J Janz Molten Carbonate Electrolytes Electiral Conductance Density
and Surface Tension of Binary and Ternary Eleclrochimica Acta 10 1965 849-857
[50] Y Takahashi R Sakamoto and MKamimoto Heat Capacities and Latent Heat of LiNO3
NaNO3 amp KNO3 International Journal of Thermophysics 9 1998 1081-1090
[51] R W Carling Heat capacities of NaNO3 and KNO3 up to 800 K Thermochimica Acta 60
1983 265-275
[52] Y Takahashi Latent heat measurement by DSC with sapphire as standard material
Thermochim Acta 88(1) 1985 199-204
101
[53] GW Hohne W Hemminger and HJ Flammersheim Differential Scanning Calorimetry
Springer-Verlag Berlin 1996
[54] W Hemminger and G Hohne Calorimetry Fundamentals and Practice Verlag Weinheim
1984
[55] M Merzlyakov and C Schick Thermal conductivity from dynamic response of DSC
Thermochimica Acta 377 2001 183-191
[56] T Kousksou A Jamil S Gibout and Y Zeraouli Thermal analysis of phase change
emulsion Journal of Thermal Analysis and Calorimetry 96 2009 841-852
[57] A Jamil T Kousksou K El Omari Y Zeraouli and Y Le Guer Heat transfer in salt
solutions enclosed in DSC cells Thermochimica Acta 507-508 2010 15-20
[58] MJ Richardson Quantitative aspects of differential scanning calorimetry Thermochimica
Acta 300 1997 15-28
[59] S Rudtsch Uncertainty of heat capacity measurements with differential scanning
calorimeters Thermochimica Acta 382 2002 17-25
[60] M J Maeso and J Largo The phase diagram of LiNO3-NaNO3 and LiNO3-KNO3 the
behavior of liquid mixtures Thermochimica Acta 223 (1993) 145-156
[61] O J Kleppa A new twin high-temperature reaction calorimeter The heats of mixing in
liquid sodium-potassium nitrates Journal of Physical Chemistry 64(12) (1960) 1937-1940
[62] G W H Hhne H K Cammenga W Eysel E Gmelin and W Hemminger The
Temperature Calibration of Scanning Calorimeters Thermochimica Acta 160 1990 1-12
[63] L B Pankratz Thermodynamic Properties of Carbides Nitrides and Other Selected
Substances U S Bureau of Mines Bulletin 696 1994
[64] M Zhang and R G Reddy Thermodynamic properties of C4mim[Tf2N] ionic liquids 0 2
2010 71-76
102
[65] D Mantha T Wang and R G Reddy Thermodynamic Modeling of Eutectic Point in the
LiNO3-NaNO3-KNO3 Ternary System Journal of Phase Equilibria and Diffusion 2011
(accepted)
[66] R G Reddy T Wang and D Mantha Determination of thermodynamic properties of
2KNO3Mg(NO3)2 Thermochimica Acta 2011 (submitted)
[67] T Wang D Mantha and R G Reddy Thermal stability of new LiNO3-NaNO3-KNO3
ternary salt for thermal energy storage system (in preparation)
[68] G D Carvalho E Frollini and W N D Santos Thermal conductivity of polymers by hot-
wire method J Appl Poly Sci 62 (1996) 2281-2285
[69] H Bloom A Doroszkowski and S B Tricklebank Molten salt mixtures IX The thermal
conductivities of molten nitrate systems Aus J Chem 18(8) (1965) 1171-1176
[70] A G Turnbull Thermal conductivity of molten salts Aus J Appl Sci 12 (1961) 30-41
[71] L R White and H T Davis Thermal conductivity of molten alkali nitrates J Chem Phys
47(1967) 5433-5439
[72] M V Peralta-Martinez M J Assael M J Dix L Karagiannidis and W A Wakeham A
Novel Instrument for the Measurement of the Thermal Conductivity of Molten Metal Part1
Instrument‟s Description Int J Thermophysics 27 (2006) 353-375
[73] Y Tada M Harada M Tanlgakl and W Eguchl Laser Flash Method for Measuring
Thermal Conductivity of Liquids Application to Molten Salts Industrial and Engineering
Chemistry Fundamentals 20 1981 333- 336
[74] M V Smirnov V A Khokhlov and E S Filatov Thermal conductivity of molten alkali
halides and their mixtures Electrochimica Acta 32 (1986) 1019-1026
[75] E Marti E Kaisersberger and W D Emmerich NEW ASPECTS OF THERMAL
ANALYSIS Part I Resolution of DSC and means for its optimization Journal of Thermal
Analysis and Calorimetry 77 2004 905-934
103
[76] E Marti E Kaisersberger G Kaiser and WY Ma Netzsch Annual 2000
bdquoThermoanalytical Characterization of Pharmaceuticals‟ Netzsch-Geraumltebau GmbH D-95100
SelbBavaria
[77] P J van Ekeren C M Holl and A J Witteveen A comparative test of differential
scanning calorimeters Journal of Thermal Analysis and Calorimetry 49 1997 1105-1114
[78] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation
Equations for Critically Evaluated Density Surface Tension Electrical Conductance and
Viscosity Data Journal of Physical and Chemical Reference Data 17 1988 1
[79] G F Petersen W A Ewing and G P Smith ldquoDensities of Some Salt Mixturesrdquo Journal of
Chemical and Engineering Data 6 1961 540
[80] P M Nasch and S G Steinemann Density and Thermal Expansion of Molten Manganese
Iron Nickel Copper Aluminum and Tin by Means of the Gamma-Ray Attenuation Technique
Physics and Chemistry of Liquids 29 1995 43-58
[81] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical and Engineering Data 6 1961 493-496
[82] D A Nissen Thermophysical Properties of the Equimolar Mixture NaNO3-KNO3 from
300degC to 600degC Journal of Chemical and Engineering Data 27 1982 269-273
[83] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate
Mixtures Journal of Chemical and Engineering Data 8 1963 469
104
APPENDIX
Appendix A
Table A1 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in solid state
(29815-40315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 342 1290 417 -025
299 027 008 000 343 1317 426 -026
300 059 018 000 344 1345 436 -027
301 091 028 000 345 1372 445 -028
302 123 037 000 346 1399 455 -029
303 154 047 000 347 1427 464 -031
304 186 056 000 348 1454 474 -032
305 217 066 000 349 1481 483 -033
306 248 076 000 350 1508 493 -035
307 279 085 000 351 1535 503 -036
308 310 095 -001 352 1562 512 -038
309 340 104 -001 353 1589 522 -039
310 371 114 -001 354 1616 532 -041
311 401 123 -001 355 1643 541 -042
312 432 133 -002 356 1670 551 -044
313 462 142 -002 357 1697 561 -045
314 492 152 -002 358 1724 570 -047
315 521 161 -003 359 1751 580 -048
316 551 171 -003 360 1777 590 -050
317 581 180 -004 361 1804 600 -052
318 610 190 -004 362 1831 610 -053
319 640 199 -005 363 1858 619 -055
320 669 209 -005 364 1885 629 -057
105
321 698 218 -006 365 1911 639 -059
322 727 228 -007 366 1938 649 -060
323 756 237 -007 367 1965 659 -062
324 785 246 -008 368 1992 669 -064
325 814 256 -009 369 2018 679 -066
326 842 265 -009 370 2045 689 -068
327 871 275 -010 371 2072 699 -070
328 899 284 -011 372 2098 709 -072
329 928 294 -012 373 2125 719 -074
330 956 303 -012 374 2152 729 -076
331 984 313 -013 375 2179 739 -078
332 1012 322 -014 376 2205 750 -080
333 1041 331 -015 377 2232 760 -082
334 1069 341 -016 378 2259 770 -084
335 1096 350 -017 379 2286 780 -086
336 1124 360 -018 380 2312 791 -088
337 1152 369 -019 381 2339 801 -090
338 1180 379 -020 382 2366 811 -093
339 1207 388 -021 383 2393 822 -095
340 1235 398 -022 384 2420 832 -097
341 1263 407 -023 38415 2424 834 -097
Table A2 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in liquid state
(40315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
40315 4287 1565 -163 514 7070 2838 -796
404 4310 1575 -167 515 7094 2850 -803
405 4337 1585 -171 516 7117 2863 -810
406 4363 1596 -175 517 7141 2875 -817
407 4390 1607 -180 518 7165 2887 -824
408 4417 1618 -184 519 7188 2899 -831
409 4443 1629 -189 520 7212 2911 -839
410 4470 1640 -193 521 7235 2924 -846
411 4496 1651 -197 522 7259 2936 -853
412 4523 1662 -202 523 7282 2948 -860
106
413 4549 1672 -206 524 7306 2960 -868
414 4576 1683 -211 525 7329 2973 -875
415 4602 1694 -216 526 7352 2985 -882
416 4629 1705 -220 527 7376 2997 -890
417 4655 1716 -225 528 7399 3010 -897
418 4681 1727 -230 529 7422 3022 -904
419 4708 1738 -234 530 7446 3034 -912
420 4734 1749 -239 531 7469 3047 -919
421 4760 1760 -244 532 7492 3059 -927
422 4786 1771 -249 533 7516 3071 -934
423 4813 1782 -253 534 7539 3084 -942
424 4839 1793 -258 535 7562 3096 -949
425 4865 1804 -263 536 7585 3109 -957
426 4891 1816 -268 537 7608 3121 -965
427 4917 1827 -273 538 7632 3134 -972
428 4943 1838 -278 539 7655 3146 -980
429 4969 1849 -283 540 7678 3158 -988
430 4995 1860 -288 541 7701 3171 -995
431 5021 1871 -293 542 7724 3183 -1003
432 5046 1882 -298 543 7747 3196 -1011
433 5072 1894 -303 544 7770 3208 -1018
434 5098 1905 -308 545 7793 3221 -1026
435 5124 1916 -313 546 7816 3233 -1034
436 5149 1927 -318 547 7839 3246 -1042
437 5175 1938 -323 548 7862 3259 -1050
438 5201 1950 -328 549 7885 3271 -1058
439 5226 1961 -334 550 7908 3284 -1066
440 5252 1972 -339 551 7931 3296 -1073
441 5278 1983 -344 552 7953 3309 -1081
442 5303 1995 -349 553 7976 3322 -1089
443 5329 2006 -355 554 7999 3334 -1097
444 5354 2017 -360 555 8022 3347 -1105
445 5380 2028 -365 556 8045 3359 -1113
446 5405 2040 -371 557 8067 3372 -1121
447 5430 2051 -376 558 8090 3385 -1130
448 5456 2062 -382 559 8113 3398 -1138
449 5481 2074 -387 560 8136 3410 -1146
450 5506 2085 -393 561 8158 3423 -1154
451 5532 2097 -398 562 8181 3436 -1162
452 5557 2108 -404 563 8204 3448 -1170
107
453 5582 2119 -409 564 8226 3461 -1178
454 5607 2131 -415 565 8249 3474 -1187
455 5633 2142 -421 566 8271 3487 -1195
456 5658 2154 -426 567 8294 3499 -1203
457 5683 2165 -432 568 8317 3512 -1212
458 5708 2177 -438 569 8339 3525 -1220
459 5733 2188 -443 570 8362 3538 -1228
460 5758 2200 -449 571 8384 3551 -1237
461 5783 2211 -455 572 8407 3564 -1245
462 5808 2223 -461 573 8429 3576 -1253
463 5833 2234 -466 574 8452 3589 -1262
464 5858 2246 -472 575 8474 3602 -1270
465 5883 2257 -478 576 8496 3615 -1279
466 5907 2269 -484 577 8519 3628 -1287
467 5932 2280 -490 578 8541 3641 -1296
468 5957 2292 -496 579 8564 3654 -1304
469 5982 2304 -502 580 8586 3667 -1313
470 6007 2315 -508 581 8608 3680 -1322
471 6031 2327 -514 582 8631 3693 -1330
472 6056 2339 -520 583 8653 3706 -1339
473 6081 2350 -526 584 8675 3719 -1348
474 6105 2362 -532 585 8697 3732 -1356
475 6130 2373 -538 586 8720 3745 -1365
476 6155 2385 -544 587 8742 3758 -1374
477 6179 2397 -551 588 8764 3771 -1382
478 6204 2409 -557 589 8786 3784 -1391
479 6228 2420 -563 590 8808 3797 -1400
480 6253 2432 -569 591 8831 3810 -1409
481 6277 2444 -575 592 8853 3823 -1418
482 6301 2456 -582 593 8875 3836 -1426
483 6326 2467 -588 594 8897 3849 -1435
484 6350 2479 -594 595 8919 3863 -1444
485 6375 2491 -601 596 8941 3876 -1453
486 6399 2503 -607 597 8963 3889 -1462
487 6423 2515 -614 598 8985 3902 -1471
488 6448 2526 -620 599 9007 3915 -1480
489 6472 2538 -626 600 9029 3928 -1489
490 6496 2550 -633 601 9051 3942 -1498
491 6520 2562 -639 602 9073 3955 -1507
492 6544 2574 -646 603 9095 3968 -1516
108
493 6569 2586 -653 604 9117 3981 -1525
494 6593 2598 -659 605 9139 3994 -1535
495 6617 2610 -666 606 9161 4008 -1544
496 6641 2621 -672 607 9183 4021 -1553
497 6665 2633 -679 608 9205 4034 -1562
498 6689 2645 -686 609 9226 4048 -1571
499 6713 2657 -692 610 9248 4061 -1581
500 6737 2669 -699 611 9270 4074 -1590
501 6761 2681 -706 612 9292 4088 -1599
502 6785 2693 -713 613 9314 4101 -1608
503 6809 2705 -719 614 9335 4114 -1618
504 6833 2717 -726 615 9357 4128 -1627
505 6856 2729 -733 616 9379 4141 -1636
506 6880 2741 -740 617 9401 4154 -1646
507 6904 2754 -747 618 9422 4168 -1655
508 6928 2766 -754 619 9444 4181 -1665
509 6952 2778 -761 620 9466 4195 -1674
510 6975 2790 -768 621 9487 4208 -1684
511 6999 2802 -775 622 9509 4222 -1693
512 7023 2814 -782 623 9531 4235 -1703
513 7047 2826 -789 62315 9534 4237 -1704
109
Appendix B
Table B1 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(29815-39215K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 347 1233 382 -046
299 022 006 000 348 1258 390 -048
300 049 014 -001 349 1283 398 -049
301 075 022 -001 350 1307 406 -051
302 101 029 -001 351 1332 415 -053
303 127 037 -002 352 1356 423 -054
304 153 044 -002 353 1381 431 -056
305 179 052 -003 354 1405 440 -058
306 205 059 -003 355 1430 448 -060
307 230 067 -004 356 1455 456 -061
308 256 075 -004 357 1479 465 -063
309 282 082 -005 358 1504 473 -065
310 308 090 -005 359 1528 482 -067
311 333 098 -006 360 1553 490 -069
312 359 105 -007 361 1577 498 -071
313 384 113 -007 362 1602 507 -073
314 410 121 -008 363 1626 515 -075
315 435 128 -009 364 1651 524 -077
316 461 136 -010 365 1675 533 -079
317 486 144 -010 366 1700 541 -081
318 511 151 -011 367 1724 550 -083
319 537 159 -012 368 1749 558 -085
320 562 167 -013 369 1773 567 -087
321 587 175 -014 370 1798 576 -089
322 612 182 -015 371 1822 584 -092
323 637 190 -016 372 1847 593 -094
324 663 198 -017 373 1871 602 -096
325 688 206 -018 374 1896 611 -098
326 713 214 -019 375 1920 620 -100
327 738 222 -020 376 1945 628 -103
328 763 229 -021 377 1969 637 -105
329 788 237 -022 378 1994 646 -107
110
330 813 245 -023 379 2018 655 -110
331 838 253 -024 380 2043 664 -112
332 863 261 -025 381 2068 673 -115
333 887 269 -027 382 2092 682 -117
334 912 277 -028 383 2117 691 -120
335 937 285 -029 384 2141 700 -122
336 962 293 -030 385 2166 709 -125
337 987 301 -032 386 2191 718 -127
338 1011 309 -033 387 2215 727 -130
339 1036 317 -034 388 2240 737 -132
340 1061 325 -036 389 2265 746 -135
341 1086 333 -037 390 2289 755 -138
342 1110 341 -039 391 2314 764 -140
343 1135 349 -040 392 2339 774 -143
344 1160 357 -042 39215 2342 775 -144
345 1184 365 -043
Table B2 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(41315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
414 3280 1149 -209 520 5608 2235 -682
415 3302 1158 -212 521 5630 2246 -687
416 3325 1167 -216 522 5651 2257 -693
417 3348 1177 -219 523 5672 2268 -698
418 3370 1186 -223 524 5694 2279 -704
419 3393 1196 -226 525 5715 2290 -710
420 3416 1205 -229 526 5736 2302 -716
421 3438 1215 -233 527 5757 2313 -721
422 3461 1224 -236 528 5779 2324 -727
423 3483 1234 -240 529 5800 2335 -733
424 3506 1243 -243 530 5821 2347 -739
425 3529 1253 -247 531 5842 2358 -745
426 3551 1263 -250 532 5864 2369 -750
427 3574 1272 -254 533 5885 2380 -756
428 3596 1282 -257 534 5906 2392 -762
429 3619 1291 -261 535 5927 2403 -768
111
430 3641 1301 -265 536 5948 2414 -774
431 3663 1311 -268 537 5970 2426 -780
432 3686 1320 -272 538 5991 2437 -786
433 3708 1330 -276 539 6012 2449 -792
434 3731 1340 -279 540 6033 2460 -798
435 3753 1350 -283 541 6054 2471 -804
436 3775 1359 -287 542 6075 2483 -810
437 3798 1369 -291 543 6096 2494 -816
438 3820 1379 -294 544 6118 2506 -822
439 3842 1389 -298 545 6139 2517 -828
440 3865 1398 -302 546 6160 2529 -835
441 3887 1408 -306 547 6181 2540 -841
442 3909 1418 -310 548 6202 2552 -847
443 3932 1428 -314 549 6223 2563 -853
444 3954 1438 -318 550 6244 2575 -859
445 3976 1448 -322 551 6265 2586 -866
446 3998 1458 -326 552 6286 2598 -872
447 4021 1468 -330 553 6307 2610 -878
448 4043 1477 -334 554 6328 2621 -884
449 4065 1487 -338 555 6349 2633 -891
450 4087 1497 -342 556 6370 2645 -897
451 4109 1507 -346 557 6391 2656 -904
452 4131 1517 -350 558 6412 2668 -910
453 4154 1527 -354 559 6433 2680 -916
454 4176 1537 -358 560 6454 2691 -923
455 4198 1547 -363 561 6475 2703 -929
456 4220 1557 -367 562 6496 2715 -936
457 4242 1568 -371 563 6517 2727 -942
458 4264 1578 -375 564 6538 2738 -949
459 4286 1588 -380 565 6559 2750 -955
460 4308 1598 -384 566 6580 2762 -962
461 4330 1608 -388 567 6600 2774 -969
462 4352 1618 -393 568 6621 2786 -975
463 4374 1628 -397 569 6642 2798 -982
464 4396 1639 -401 570 6663 2810 -988
465 4418 1649 -406 571 6684 2821 -995
466 4440 1659 -410 572 6705 2833 -1002
467 4462 1669 -415 573 6726 2845 -1009
468 4484 1680 -419 574 6747 2857 -1015
469 4506 1690 -424 575 6767 2869 -1022
112
470 4528 1700 -428 576 6788 2881 -1029
471 4550 1710 -433 577 6809 2893 -1036
472 4572 1721 -437 578 6830 2905 -1042
473 4593 1731 -442 579 6851 2917 -1049
474 4615 1741 -446 580 6871 2929 -1056
475 4637 1752 -451 581 6892 2941 -1063
476 4659 1762 -456 582 6913 2953 -1070
477 4681 1773 -460 583 6934 2966 -1077
478 4703 1783 -465 584 6954 2978 -1084
479 4724 1793 -470 585 6975 2990 -1091
480 4746 1804 -474 586 6996 3002 -1098
481 4768 1814 -479 587 7017 3014 -1105
482 4790 1825 -484 588 7037 3026 -1112
483 4812 1835 -489 589 7058 3038 -1119
484 4833 1846 -494 590 7079 3051 -1126
485 4855 1856 -498 591 7100 3063 -1133
486 4877 1867 -503 592 7120 3075 -1140
487 4898 1877 -508 593 7141 3087 -1147
488 4920 1888 -513 594 7162 3100 -1154
489 4942 1899 -518 595 7182 3112 -1162
490 4963 1909 -523 596 7203 3124 -1169
491 4985 1920 -528 597 7224 3137 -1176
492 5007 1930 -533 598 7244 3149 -1183
493 5028 1941 -538 599 7265 3161 -1190
494 5050 1952 -543 600 7285 3174 -1198
495 5072 1962 -548 601 7306 3186 -1205
496 5093 1973 -553 602 7327 3198 -1212
497 5115 1984 -558 603 7347 3211 -1220
498 5136 1995 -563 604 7368 3223 -1227
499 5158 2005 -568 605 7389 3236 -1234
500 5180 2016 -574 606 7409 3248 -1242
501 5201 2027 -579 607 7430 3261 -1249
502 5223 2038 -584 608 7450 3273 -1257
503 5244 2049 -589 609 7471 3286 -1264
504 5266 2059 -595 610 7491 3298 -1272
505 5287 2070 -600 611 7512 3311 -1279
506 5309 2081 -605 612 7532 3323 -1287
507 5330 2092 -610 613 7553 3336 -1294
508 5352 2103 -616 614 7573 3348 -1302
509 5373 2114 -621 615 7594 3361 -1309
113
510 5394 2125 -627 616 7615 3374 -1317
511 5416 2136 -632 617 7635 3386 -1325
512 5437 2147 -637 618 7656 3399 -1332
513 5459 2158 -643 619 7676 3412 -1340
514 5480 2169 -648 620 7696 3424 -1348
515 5502 2180 -654 621 7717 3437 -1355
516 5523 2191 -659 622 7737 3450 -1363
517 5544 2202 -665 623 7758 3462 -1371
518 5566 2213 -670 62315 7761 3464 -1372
114
Appendix C
Table C1 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in solid
state (29815-36415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 333 1937 611 -034
299 048 014 000 334 1992 629 -036
300 104 031 000 335 2047 647 -038
301 160 048 000 336 2102 666 -040
302 216 065 000 337 2156 684 -042
303 272 082 -001 338 2211 703 -045
304 329 099 -001 339 2266 721 -047
305 385 116 -001 340 2321 740 -049
306 441 133 -002 341 2375 758 -052
307 496 150 -002 342 2430 777 -054
308 552 167 -003 343 2485 796 -056
309 608 185 -003 344 2539 815 -059
310 664 202 -004 345 2594 833 -062
311 720 219 -005 346 2648 852 -064
312 776 236 -006 347 2703 871 -067
313 831 254 -006 348 2757 890 -070
314 887 271 -007 349 2812 909 -072
315 942 289 -008 350 2866 928 -075
316 998 306 -009 351 2921 947 -078
317 1054 324 -010 352 2975 966 -081
318 1109 341 -011 353 3029 985 -084
319 1164 359 -012 354 3084 1004 -087
320 1220 377 -014 355 3138 1024 -090
321 1275 395 -015 356 3192 1043 -094
322 1331 412 -016 357 3246 1062 -097
323 1386 430 -018 358 3300 1082 -100
324 1441 448 -019 359 3355 1101 -103
325 1496 466 -020 360 3409 1120 -107
326 1552 484 -022 361 3463 1140 -110
327 1607 502 -024 362 3517 1159 -114
328 1662 520 -025 363 3571 1179 -117
329 1717 538 -027 364 3625 1199 -121
115
330 1772 556 -029 36415 3633 1202 -121
331 1827 574 -030
332 1882 593 -032
Table C2 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in liquid
state (42115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
42115 7428 2673 -455 523 11788 4725 -1440
422 7468 2690 -461 524 11827 4745 -1452
423 7515 2710 -468 525 11866 4766 -1464
424 7562 2730 -476 526 11904 4786 -1476
425 7608 2750 -484 527 11943 4807 -1488
426 7655 2770 -491 528 11982 4827 -1500
427 7702 2790 -499 529 12021 4847 -1512
428 7748 2810 -507 530 12059 4868 -1524
429 7795 2830 -514 531 12098 4888 -1536
430 7841 2849 -522 532 12137 4909 -1548
431 7887 2869 -530 533 12175 4929 -1560
432 7933 2889 -538 534 12213 4950 -1572
433 7979 2909 -546 535 12252 4970 -1584
434 8025 2929 -554 536 12290 4991 -1597
435 8071 2949 -562 537 12328 5011 -1609
436 8117 2969 -570 538 12366 5032 -1621
437 8163 2989 -578 539 12404 5052 -1634
438 8208 3009 -586 540 12442 5073 -1646
439 8254 3029 -595 541 12480 5093 -1659
440 8299 3049 -603 542 12518 5114 -1671
441 8345 3069 -611 543 12556 5134 -1684
442 8390 3089 -620 544 12594 5155 -1696
443 8435 3109 -628 545 12632 5175 -1709
444 8480 3129 -636 546 12669 5196 -1721
445 8525 3149 -645 547 12707 5217 -1734
446 8570 3169 -654 548 12745 5237 -1747
116
447 8615 3189 -662 549 12782 5258 -1760
448 8659 3209 -671 550 12820 5278 -1772
449 8704 3229 -679 551 12857 5299 -1785
450 8748 3249 -688 552 12894 5319 -1798
451 8793 3269 -697 553 12932 5340 -1811
452 8837 3289 -706 554 12969 5361 -1824
453 8881 3309 -715 555 13006 5381 -1837
454 8926 3329 -724 556 13043 5402 -1850
455 8970 3349 -732 557 13080 5422 -1863
456 9014 3369 -741 558 13117 5443 -1876
457 9058 3389 -750 559 13154 5464 -1889
458 9102 3409 -760 560 13191 5484 -1902
459 9145 3429 -769 561 13228 5505 -1916
460 9189 3449 -778 562 13264 5526 -1929
461 9233 3469 -787 563 13301 5546 -1942
462 9276 3489 -796 564 13338 5567 -1956
463 9319 3509 -806 565 13374 5588 -1969
464 9363 3529 -815 566 13411 5608 -1982
465 9406 3549 -824 567 13447 5629 -1996
466 9449 3570 -834 568 13484 5650 -2009
467 9492 3590 -843 569 13520 5670 -2023
468 9535 3610 -853 570 13557 5691 -2036
469 9578 3630 -862 571 13593 5712 -2050
470 9621 3650 -872 572 13629 5732 -2063
471 9664 3670 -882 573 13665 5753 -2077
472 9707 3690 -891 574 13701 5774 -2091
473 9749 3710 -901 575 13737 5795 -2104
474 9792 3731 -911 576 13773 5815 -2118
475 9834 3751 -921 577 13809 5836 -2132
476 9877 3771 -930 578 13845 5857 -2146
477 9919 3791 -940 579 13881 5877 -2160
478 9961 3811 -950 580 13917 5898 -2174
479 10004 3831 -960 581 13953 5919 -2188
480 10046 3852 -970 582 13988 5940 -2202
481 10088 3872 -980 583 14024 5960 -2216
482 10130 3892 -990 584 14060 5981 -2230
483 10171 3912 -1001 585 14095 6002 -2244
484 10213 3932 -1011 586 14131 6023 -2258
485 10255 3953 -1021 587 14166 6044 -2272
486 10297 3973 -1031 588 14201 6064 -2286
117
487 10338 3993 -1042 589 14237 6085 -2300
488 10380 4013 -1052 590 14272 6106 -2315
489 10421 4034 -1062 591 14307 6127 -2329
490 10462 4054 -1073 592 14342 6148 -2343
491 10504 4074 -1083 593 14378 6168 -2358
492 10545 4094 -1094 594 14413 6189 -2372
493 10586 4114 -1104 595 14448 6210 -2386
494 10627 4135 -1115 596 14483 6231 -2401
495 10668 4155 -1126 597 14518 6252 -2415
496 10709 4175 -1136 598 14552 6273 -2430
497 10750 4196 -1147 599 14587 6293 -2444
498 10791 4216 -1158 600 14622 6314 -2459
499 10831 4236 -1169 601 14657 6335 -2474
500 10872 4256 -1179 602 14692 6356 -2488
501 10912 4277 -1190 603 14726 6377 -2503
502 10953 4297 -1201 604 14761 6398 -2518
503 10993 4317 -1212 605 14795 6419 -2533
504 11034 4338 -1223 606 14830 6439 -2547
505 11074 4358 -1234 607 14864 6460 -2562
506 11114 4378 -1245 608 14899 6481 -2577
507 11154 4399 -1257 609 14933 6502 -2592
508 11194 4419 -1268 610 14967 6523 -2607
509 11234 4439 -1279 611 15002 6544 -2622
510 11274 4460 -1290 612 15036 6565 -2637
511 11314 4480 -1302 613 15070 6586 -2652
512 11354 4500 -1313 614 15104 6607 -2667
513 11394 4521 -1324 615 15138 6628 -2682
514 11433 4541 -1336 616 15172 6649 -2697
515 11473 4562 -1347 617 15206 6670 -2713
516 11513 4582 -1359 618 15240 6691 -2728
517 11552 4602 -1370 619 15274 6712 -2743
518 11591 4623 -1382 620 15308 6733 -2758
519 11631 4643 -1393 621 15342 6754 -2774
520 11670 4664 -1405 622 15375 6774 -2789
521 11709 4684 -1417 623 15409 6795 -2804
522 11748 4704 -1428 62315 15414 6799 -2807
118
Appendix D
Table D1 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in solid state
(29815-36315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
299 021 006 000 333 867 277 -012
300 047 014 000 334 891 285 -012
301 072 022 000 335 916 293 -013
302 097 029 000 336 940 302 -014
303 122 037 000 337 964 310 -015
304 147 045 000 338 989 318 -016
305 172 053 000 339 1013 327 -017
306 197 060 000 340 1037 335 -018
307 223 068 000 341 1061 343 -019
308 248 076 000 342 1085 352 -019
309 273 084 000 343 1109 360 -020
310 298 092 -001 344 1134 369 -021
311 323 099 -001 345 1158 377 -022
312 348 107 -001 346 1182 385 -024
313 373 115 -001 347 1206 394 -025
314 398 123 -002 348 1230 402 -026
315 423 131 -002 349 1254 411 -027
316 447 139 -002 350 1277 419 -028
317 472 147 -003 351 1301 428 -029
318 497 155 -003 352 1325 436 -030
319 522 163 -003 353 1349 445 -032
320 547 171 -004 354 1373 453 -033
321 572 179 -004 355 1396 462 -034
322 596 187 -005 356 1420 470 -035
323 621 195 -005 357 1444 479 -037
324 646 203 -006 358 1467 487 -038
325 670 211 -006 359 1491 496 -039
326 695 220 -007 360 1514 504 -041
327 720 228 -008 361 1538 513 -042
328 744 236 -008 362 1561 522 -043
329 769 244 -009 363 1584 530 -045
330 793 252 -010 36315 1588 532 -045
119
331 818 260 -010
Table D2 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in liquid
state (38115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
38115 2281 765 -104 503 5639 2242 -594
382 2307 775 -106 504 5664 2255 -600
383 2338 787 -109 505 5689 2267 -606
384 2369 798 -111 506 5713 2280 -611
385 2399 810 -113 507 5738 2292 -617
386 2430 822 -116 508 5763 2305 -623
387 2460 834 -118 509 5787 2317 -629
388 2491 846 -121 510 5812 2330 -634
389 2521 857 -123 511 5836 2342 -640
390 2551 869 -126 512 5861 2355 -646
391 2582 881 -128 513 5885 2367 -652
392 2612 893 -131 514 5910 2380 -658
393 2642 905 -134 515 5934 2392 -664
394 2672 917 -136 516 5959 2405 -670
395 2702 928 -139 517 5983 2417 -676
396 2732 940 -142 518 6007 2430 -682
397 2762 952 -144 519 6032 2443 -688
398 2792 964 -147 520 6056 2455 -694
399 2821 976 -150 521 6080 2468 -700
400 2851 988 -153 522 6104 2480 -706
401 2881 999 -156 523 6128 2493 -712
402 2910 1011 -159 524 6152 2506 -718
403 2940 1023 -162 525 6176 2518 -724
404 2969 1035 -164 526 6200 2531 -731
405 2999 1047 -167 527 6224 2544 -737
406 3028 1059 -170 528 6248 2556 -743
407 3057 1071 -174 529 6272 2569 -749
408 3087 1083 -177 530 6296 2581 -756
120
409 3116 1095 -180 531 6320 2594 -762
410 3145 1107 -183 532 6344 2607 -768
411 3174 1119 -186 533 6368 2619 -775
412 3203 1130 -189 534 6391 2632 -781
413 3232 1142 -192 535 6415 2645 -787
414 3261 1154 -196 536 6439 2657 -794
415 3290 1166 -199 537 6462 2670 -800
416 3319 1178 -202 538 6486 2683 -807
417 3347 1190 -206 539 6510 2696 -813
418 3376 1202 -209 540 6533 2708 -820
419 3405 1214 -212 541 6557 2721 -826
420 3433 1226 -216 542 6580 2734 -833
421 3462 1238 -219 543 6604 2746 -839
422 3490 1250 -223 544 6627 2759 -846
423 3519 1262 -226 545 6650 2772 -853
424 3547 1274 -230 546 6674 2785 -859
425 3575 1286 -233 547 6697 2797 -866
426 3604 1298 -237 548 6720 2810 -873
427 3632 1310 -240 549 6744 2823 -879
428 3660 1322 -244 550 6767 2836 -886
429 3688 1334 -248 551 6790 2848 -893
430 3716 1346 -251 552 6813 2861 -900
431 3744 1358 -255 553 6836 2874 -907
432 3772 1371 -259 554 6860 2887 -913
433 3800 1383 -263 555 6883 2900 -920
434 3828 1395 -267 556 6906 2912 -927
435 3856 1407 -270 557 6929 2925 -934
436 3883 1419 -274 558 6952 2938 -941
437 3911 1431 -278 559 6975 2951 -948
438 3939 1443 -282 560 6998 2964 -955
439 3966 1455 -286 561 7020 2976 -962
440 3994 1467 -290 562 7043 2989 -969
441 4021 1479 -294 563 7066 3002 -976
442 4049 1491 -298 564 7089 3015 -983
443 4076 1504 -302 565 7112 3028 -990
444 4103 1516 -306 566 7134 3041 -997
445 4131 1528 -310 567 7157 3054 -1005
446 4158 1540 -314 568 7180 3066 -1012
447 4185 1552 -319 569 7203 3079 -1019
448 4212 1564 -323 570 7225 3092 -1026
121
449 4240 1576 -327 571 7248 3105 -1033
450 4267 1589 -331 572 7270 3118 -1041
451 4294 1601 -336 573 7293 3131 -1048
452 4321 1613 -340 574 7315 3144 -1055
453 4347 1625 -344 575 7338 3157 -1063
454 4374 1637 -349 576 7360 3170 -1070
455 4401 1650 -353 577 7383 3183 -1077
456 4428 1662 -357 578 7405 3196 -1085
457 4455 1674 -362 579 7428 3208 -1092
458 4481 1686 -366 580 7450 3221 -1100
459 4508 1698 -371 581 7472 3234 -1107
460 4535 1711 -375 582 7494 3247 -1114
461 4561 1723 -380 583 7517 3260 -1122
462 4588 1735 -384 584 7539 3273 -1129
463 4614 1747 -389 585 7561 3286 -1137
464 4641 1760 -394 586 7583 3299 -1145
465 4667 1772 -398 587 7605 3312 -1152
466 4693 1784 -403 588 7628 3325 -1160
467 4720 1796 -408 589 7650 3338 -1167
468 4746 1809 -412 590 7672 3351 -1175
469 4772 1821 -417 591 7694 3364 -1183
470 4798 1833 -422 592 7716 3377 -1191
471 4825 1846 -427 593 7738 3390 -1198
472 4851 1858 -432 594 7760 3403 -1206
473 4877 1870 -437 595 7782 3416 -1214
474 4903 1882 -441 596 7804 3429 -1222
475 4929 1895 -446 597 7825 3442 -1229
476 4955 1907 -451 598 7847 3455 -1237
477 4980 1919 -456 599 7869 3469 -1245
478 5006 1932 -461 600 7891 3482 -1253
479 5032 1944 -466 601 7913 3495 -1261
480 5058 1956 -471 602 7934 3508 -1269
481 5083 1969 -476 603 7956 3521 -1277
482 5109 1981 -481 604 7978 3534 -1285
483 5135 1994 -487 605 8000 3547 -1293
484 5160 2006 -492 606 8021 3560 -1301
485 5186 2018 -497 607 8043 3573 -1309
486 5211 2031 -502 608 8064 3586 -1317
487 5237 2043 -507 609 8086 3599 -1325
488 5262 2055 -513 610 8107 3613 -1333
122
489 5288 2068 -518 611 8129 3626 -1341
490 5313 2080 -523 612 8150 3639 -1349
491 5338 2093 -528 613 8172 3652 -1357
492 5364 2105 -534 614 8193 3665 -1366
493 5389 2117 -539 615 8215 3678 -1374
494 5414 2130 -545 616 8236 3692 -1382
495 5439 2142 -550 617 8258 3705 -1390
496 5464 2155 -555 618 8279 3718 -1398
497 5489 2167 -561 619 8300 3731 -1407
498 5514 2180 -566 620 8321 3744 -1415
499 5539 2192 -572 621 8343 3757 -1423
500 5564 2205 -578 622 8364 3771 -1432
501 5589 2217 -583 623 8385 3784 -1441
502 5614 2230 -589 62315 8388 3786 -1443
123
Appendix E
Table E1 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in solid state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 913 287 -014
299 025 007 000 331 941 296 -015
300 054 016 000 332 970 306 -016
301 083 025 000 333 998 315 -017
302 112 034 000 334 1026 324 -018
303 141 042 000 335 1054 334 -019
304 170 051 000 336 1081 343 -020
305 199 060 -001 337 1109 353 -021
306 228 069 -001 338 1137 362 -022
307 257 078 -001 339 1165 371 -024
308 286 087 -001 340 1193 381 -025
309 315 096 -002 341 1221 390 -026
310 343 105 -002 342 1248 400 -027
311 372 113 -002 343 1276 409 -028
312 401 122 -003 344 1304 419 -030
313 430 131 -003 345 1331 428 -031
314 458 140 -003 346 1359 438 -032
315 487 149 -004 347 1386 447 -034
316 516 159 -004 348 1414 457 -035
317 544 168 -005 349 1441 466 -036
318 573 177 -006 350 1468 476 -038
319 602 186 -006 351 1496 486 -039
320 630 195 -007 352 1523 495 -041
321 659 204 -007 353 1550 505 -042
322 687 213 -008 354 1577 514 -044
323 715 222 -009 355 1605 524 -046
324 744 232 -009 356 1632 534 -047
325 772 241 -010 357 1659 543 -049
326 800 250 -011 358 1686 553 -050
327 829 259 -012 359 1713 563 -052
328 857 269 -013 35915 1717 564 -052
329 885 278 -013
124
Table E2 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in liquid state (376-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2323 777 -094 500 5525 2173 -590
376 2347 786 -096 501 5548 2184 -595
377 2375 797 -098 502 5572 2196 -601
378 2403 808 -101 503 5595 2208 -606
379 2431 818 -103 504 5619 2220 -612
380 2459 829 -106 505 5642 2232 -618
381 2487 839 -108 506 5665 2243 -623
382 2515 850 -111 507 5689 2255 -629
383 2542 861 -113 508 5712 2267 -635
384 2570 871 -116 509 5735 2279 -640
385 2598 882 -118 510 5759 2291 -646
386 2626 893 -121 511 5782 2303 -652
387 2653 903 -123 512 5805 2315 -658
388 2681 914 -126 513 5828 2326 -664
389 2708 925 -129 514 5852 2338 -669
390 2736 935 -132 515 5875 2350 -675
391 2763 946 -134 516 5898 2362 -681
392 2791 957 -137 517 5921 2374 -687
393 2818 968 -140 518 5944 2386 -693
394 2845 978 -143 519 5967 2398 -699
395 2873 989 -146 520 5990 2410 -705
396 2900 1000 -148 521 6013 2422 -711
397 2927 1011 -151 522 6036 2434 -717
398 2954 1022 -154 523 6059 2446 -723
399 2981 1032 -157 524 6082 2458 -729
400 3008 1043 -160 525 6105 2470 -735
401 3035 1054 -163 526 6128 2482 -741
402 3062 1065 -166 527 6151 2494 -747
403 3089 1076 -169 528 6173 2506 -754
404 3116 1086 -172 529 6196 2518 -760
405 3143 1097 -176 530 6219 2530 -766
125
406 3170 1108 -179 531 6242 2542 -772
407 3197 1119 -182 532 6265 2554 -778
408 3223 1130 -185 533 6287 2566 -785
409 3250 1141 -188 534 6310 2578 -791
410 3277 1152 -192 535 6333 2591 -797
411 3303 1163 -195 536 6355 2603 -804
412 3330 1174 -198 537 6378 2615 -810
413 3356 1185 -202 538 6400 2627 -816
414 3383 1195 -205 539 6423 2639 -823
415 3409 1206 -208 540 6445 2651 -829
416 3436 1217 -212 541 6468 2663 -836
417 3462 1228 -215 542 6490 2676 -842
418 3488 1239 -219 543 6513 2688 -849
419 3515 1250 -222 544 6535 2700 -855
420 3541 1261 -226 545 6558 2712 -862
421 3567 1272 -229 546 6580 2724 -868
422 3593 1283 -233 547 6602 2737 -875
423 3619 1294 -236 548 6625 2749 -882
424 3645 1305 -240 549 6647 2761 -888
425 3671 1317 -244 550 6669 2773 -895
426 3697 1328 -247 551 6692 2786 -902
427 3723 1339 -251 552 6714 2798 -908
428 3749 1350 -255 553 6736 2810 -915
429 3775 1361 -259 554 6758 2822 -922
430 3801 1372 -262 555 6780 2835 -929
431 3827 1383 -266 556 6803 2847 -935
432 3852 1394 -270 557 6825 2859 -942
433 3878 1405 -274 558 6847 2872 -949
434 3904 1416 -278 559 6869 2884 -956
435 3929 1428 -282 560 6891 2896 -963
436 3955 1439 -286 561 6913 2909 -970
437 3981 1450 -290 562 6935 2921 -977
438 4006 1461 -294 563 6957 2933 -983
439 4032 1472 -298 564 6979 2946 -990
440 4057 1483 -302 565 7001 2958 -997
441 4083 1495 -306 566 7023 2971 -1004
442 4108 1506 -310 567 7045 2983 -1011
443 4133 1517 -314 568 7067 2995 -1019
444 4159 1528 -318 569 7089 3008 -1026
445 4184 1540 -322 570 7110 3020 -1033
126
446 4209 1551 -327 571 7132 3033 -1040
447 4234 1562 -331 572 7154 3045 -1047
448 4260 1573 -335 573 7176 3058 -1054
449 4285 1585 -339 574 7198 3070 -1061
450 4310 1596 -344 575 7219 3083 -1069
451 4335 1607 -348 576 7241 3095 -1076
452 4360 1618 -352 577 7263 3108 -1083
453 4385 1630 -357 578 7284 3120 -1090
454 4410 1641 -361 579 7306 3133 -1098
455 4435 1652 -365 580 7328 3145 -1105
456 4460 1664 -370 581 7349 3158 -1112
457 4485 1675 -374 582 7371 3170 -1120
458 4510 1687 -379 583 7393 3183 -1127
459 4534 1698 -383 584 7414 3195 -1134
460 4559 1709 -388 585 7436 3208 -1142
461 4584 1721 -393 586 7457 3221 -1149
462 4609 1732 -397 587 7479 3233 -1157
463 4633 1743 -402 588 7500 3246 -1164
464 4658 1755 -406 589 7522 3258 -1172
465 4683 1766 -411 590 7543 3271 -1179
466 4707 1778 -416 591 7564 3284 -1187
467 4732 1789 -420 592 7586 3296 -1194
468 4756 1801 -425 593 7607 3309 -1202
469 4781 1812 -430 594 7628 3322 -1210
470 4805 1824 -435 595 7650 3334 -1217
471 4830 1835 -440 596 7671 3347 -1225
472 4854 1847 -444 597 7692 3360 -1233
473 4878 1858 -449 598 7714 3373 -1240
474 4903 1870 -454 599 7735 3385 -1248
475 4927 1881 -459 600 7756 3398 -1256
476 4951 1893 -464 601 7777 3411 -1264
477 4975 1904 -469 602 7799 3423 -1271
478 5000 1916 -474 603 7820 3436 -1279
479 5024 1927 -479 604 7841 3449 -1287
480 5048 1939 -484 605 7862 3462 -1295
481 5072 1951 -489 606 7883 3475 -1303
482 5096 1962 -494 607 7904 3487 -1311
483 5120 1974 -499 608 7925 3500 -1318
484 5144 1985 -504 609 7946 3513 -1326
485 5168 1997 -510 610 7967 3526 -1334
127
486 5192 2009 -515 611 7988 3539 -1342
487 5216 2020 -520 612 8009 3551 -1350
488 5240 2032 -525 613 8030 3564 -1358
489 5264 2044 -530 614 8051 3577 -1366
490 5288 2055 -536 615 8072 3590 -1374
491 5312 2067 -541 616 8093 3603 -1383
492 5335 2079 -546 617 8114 3616 -1391
493 5359 2090 -552 618 8135 3629 -1399
494 5383 2102 -557 619 8156 3642 -1407
495 5407 2114 -562 620 8177 3655 -1415
496 5430 2126 -568 621 8198 3667 -1423
497 5454 2137 -573 622 8219 3680 -1431
498 5478 2149 -579 623 8239 3693 -1440
499 5501 2161 -584 62315 8242 3695 -1441
128
Appendix F
Table F1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in solid
state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 1063 334 -017
299 029 009 000 331 1096 345 -018
300 063 019 000 332 1128 356 -019
301 097 029 000 333 1161 366 -020
302 131 039 000 334 1193 377 -021
303 165 050 000 335 1225 388 -022
304 199 060 -001 336 1258 399 -024
305 233 070 -001 337 1290 410 -025
306 267 081 -001 338 1322 421 -026
307 300 091 -001 339 1355 432 -028
308 334 101 -002 340 1387 443 -029
309 368 112 -002 341 1419 454 -030
310 401 122 -002 342 1451 464 -032
311 435 133 -003 343 1483 475 -033
312 468 143 -003 344 1515 486 -035
313 502 153 -004 345 1547 497 -036
314 535 164 -004 346 1578 508 -038
315 569 174 -005 347 1610 519 -039
316 602 185 -005 348 1642 531 -041
317 635 196 -006 349 1674 542 -043
318 668 206 -006 350 1705 553 -044
319 702 217 -007 351 1737 564 -046
320 735 227 -008 352 1769 575 -048
321 768 238 -009 353 1800 586 -049
322 801 248 -009 354 1832 597 -051
323 834 259 -010 355 1863 608 -053
324 867 270 -011 356 1894 619 -055
325 900 280 -012 357 1926 631 -057
326 932 291 -013 358 1957 642 -059
327 965 302 -014 359 1988 653 -061
328 998 313 -015 35915 1993 655 -061
329 1030 323 -016
129
Table F2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in liquid
state (37515-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2691 926 -083 500 6111 2416 -640
376 2717 936 -085 501 6136 2428 -646
377 2747 948 -088 502 6161 2440 -652
378 2778 959 -091 503 6185 2453 -658
379 2808 971 -094 504 6210 2465 -665
380 2838 982 -096 505 6235 2478 -671
381 2869 994 -099 506 6259 2490 -677
382 2899 1005 -102 507 6284 2502 -683
383 2929 1017 -105 508 6308 2515 -690
384 2959 1028 -108 509 6333 2527 -696
385 2989 1040 -111 510 6357 2540 -702
386 3019 1051 -114 511 6381 2552 -709
387 3049 1063 -117 512 6406 2565 -715
388 3079 1075 -120 513 6430 2577 -721
389 3109 1086 -123 514 6454 2590 -728
390 3138 1098 -126 515 6479 2602 -734
391 3168 1109 -129 516 6503 2615 -741
392 3198 1121 -133 517 6527 2627 -747
393 3227 1132 -136 518 6551 2640 -754
394 3257 1144 -139 519 6575 2652 -760
395 3286 1156 -142 520 6599 2665 -767
396 3316 1167 -146 521 6624 2677 -774
397 3345 1179 -149 522 6648 2690 -780
398 3374 1191 -152 523 6672 2702 -787
399 3403 1202 -156 524 6696 2715 -794
400 3433 1214 -159 525 6719 2727 -800
401 3462 1226 -163 526 6743 2740 -807
402 3491 1237 -166 527 6767 2753 -814
403 3520 1249 -170 528 6791 2765 -821
404 3549 1261 -173 529 6815 2778 -827
405 3578 1272 -177 530 6839 2790 -834
130
406 3606 1284 -180 531 6862 2803 -841
407 3635 1296 -184 532 6886 2815 -848
408 3664 1307 -187 533 6910 2828 -855
409 3693 1319 -191 534 6933 2841 -862
410 3721 1331 -195 535 6957 2853 -869
411 3750 1343 -199 536 6981 2866 -876
412 3778 1354 -202 537 7004 2879 -883
413 3807 1366 -206 538 7028 2891 -890
414 3835 1378 -210 539 7051 2904 -897
415 3864 1390 -214 540 7075 2917 -904
416 3892 1401 -218 541 7098 2929 -911
417 3920 1413 -222 542 7122 2942 -918
418 3948 1425 -226 543 7145 2955 -925
419 3977 1437 -230 544 7168 2967 -932
420 4005 1449 -234 545 7192 2980 -939
421 4033 1460 -238 546 7215 2993 -947
422 4061 1472 -242 547 7238 3005 -954
423 4089 1484 -246 548 7261 3018 -961
424 4117 1496 -250 549 7285 3031 -968
425 4145 1508 -254 550 7308 3044 -976
426 4172 1519 -258 551 7331 3056 -983
427 4200 1531 -262 552 7354 3069 -990
428 4228 1543 -266 553 7377 3082 -998
429 4256 1555 -271 554 7400 3095 -1005
430 4283 1567 -275 555 7423 3107 -1013
431 4311 1579 -279 556 7446 3120 -1020
432 4338 1591 -284 557 7469 3133 -1027
433 4366 1603 -288 558 7492 3146 -1035
434 4393 1614 -292 559 7515 3159 -1042
435 4421 1626 -297 560 7538 3171 -1050
436 4448 1638 -301 561 7561 3184 -1058
437 4475 1650 -306 562 7584 3197 -1065
438 4503 1662 -310 563 7607 3210 -1073
439 4530 1674 -315 564 7629 3223 -1080
440 4557 1686 -319 565 7652 3235 -1088
441 4584 1698 -324 566 7675 3248 -1096
442 4611 1710 -328 567 7697 3261 -1103
443 4638 1722 -333 568 7720 3274 -1111
444 4665 1734 -338 569 7743 3287 -1119
445 4692 1746 -342 570 7765 3300 -1126
131
446 4719 1758 -347 571 7788 3313 -1134
447 4746 1770 -352 572 7811 3326 -1142
448 4773 1782 -356 573 7833 3338 -1150
449 4800 1794 -361 574 7856 3351 -1158
450 4826 1806 -366 575 7878 3364 -1166
451 4853 1818 -371 576 7901 3377 -1173
452 4880 1830 -376 577 7923 3390 -1181
453 4906 1842 -381 578 7945 3403 -1189
454 4933 1854 -386 579 7968 3416 -1197
455 4959 1866 -391 580 7990 3429 -1205
456 4986 1878 -396 581 8012 3442 -1213
457 5012 1890 -401 582 8035 3455 -1221
458 5039 1902 -406 583 8057 3468 -1229
459 5065 1914 -411 584 8079 3481 -1237
460 5091 1926 -416 585 8101 3494 -1245
461 5118 1938 -421 586 8124 3507 -1254
462 5144 1951 -426 587 8146 3520 -1262
463 5170 1963 -431 588 8168 3533 -1270
464 5196 1975 -436 589 8190 3546 -1278
465 5222 1987 -441 590 8212 3559 -1286
466 5248 1999 -447 591 8234 3572 -1294
467 5274 2011 -452 592 8256 3585 -1303
468 5300 2023 -457 593 8278 3598 -1311
469 5326 2035 -463 594 8300 3611 -1319
470 5352 2048 -468 595 8322 3624 -1328
471 5378 2060 -473 596 8344 3637 -1336
472 5404 2072 -479 597 8366 3650 -1344
473 5430 2084 -484 598 8388 3663 -1353
474 5455 2096 -490 599 8410 3676 -1361
475 5481 2108 -495 600 8432 3690 -1369
476 5507 2121 -500 601 8454 3703 -1378
477 5532 2133 -506 602 8475 3716 -1386
478 5558 2145 -512 603 8497 3729 -1395
479 5583 2157 -517 604 8519 3742 -1403
480 5609 2170 -523 605 8541 3755 -1412
481 5634 2182 -528 606 8562 3768 -1420
482 5660 2194 -534 607 8584 3781 -1429
483 5685 2206 -540 608 8606 3795 -1438
484 5710 2219 -545 609 8627 3808 -1446
485 5736 2231 -551 610 8649 3821 -1455
132
486 5761 2243 -557 611 8670 3834 -1464
487 5786 2255 -563 612 8692 3847 -1472
488 5812 2268 -568 613 8713 3860 -1481
489 5837 2280 -574 614 8735 3874 -1490
490 5862 2292 -580 615 8756 3887 -1498
491 5887 2305 -586 616 8778 3900 -1507
492 5912 2317 -592 617 8799 3913 -1516
493 5937 2329 -598 618 8821 3926 -1525
494 5962 2342 -604 619 8842 3940 -1534
495 5987 2354 -610 620 8864 3953 -1542
496 6012 2366 -616 621 8885 3966 -1551
497 6037 2379 -622 622 8906 3979 -1560
498 6062 2391 -628 623 8928 3993 -1569
499 6086 2403 -634 62315 8931 3995 -1570
133
Appendix G
Table G1 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid I state (29815-33715K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 319 578 162 -004
299 024 000 000 320 606 170 -005
300 052 000 000 321 633 179 -005
301 080 007 000 322 660 188 -006
302 108 016 000 323 688 197 -007
303 136 024 000 324 715 205 -007
304 164 032 000 325 742 214 -008
305 192 041 000 326 769 223 -009
306 219 049 000 327 796 232 -009
307 247 058 000 328 823 241 -010
308 275 067 -001 329 851 250 -011
309 303 075 -001 330 878 259 -011
310 330 084 -001 331 905 268 -012
311 358 092 -001 332 932 277 -013
312 386 101 -002 333 959 285 -014
313 413 109 -002 334 985 294 -015
314 441 118 -002 335 1012 303 -016
315 468 127 -003 336 1039 312 -017
316 496 135 -003 337 1066 321 -018
317 523 144 -003 33715 1070 331 -019
318 551 153 -004
Table G2 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid II state (36115-36415K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36115 2433 825 -054
134
362 2454 832 -056
363 2478 841 -059
364 2503 850 -061
36415 2506 851 -062
Table G3 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
liquid state (41115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
41115 3833 1366 -210 518 6604 2649 -772
412 3857 1376 -213 519 6628 2661 -778
413 3885 1387 -217 520 6652 2674 -785
414 3913 1399 -221 521 6675 2686 -792
415 3941 1411 -225 522 6699 2699 -798
416 3969 1422 -229 523 6723 2711 -805
417 3997 1434 -233 524 6747 2723 -812
418 4025 1446 -237 525 6770 2736 -819
419 4053 1457 -241 526 6794 2748 -825
420 4081 1469 -245 527 6818 2761 -832
421 4109 1481 -249 528 6841 2773 -839
422 4137 1493 -253 529 6865 2786 -846
423 4165 1504 -257 530 6888 2798 -853
424 4192 1516 -262 531 6912 2810 -860
425 4220 1528 -266 532 6935 2823 -867
426 4248 1539 -270 533 6959 2835 -873
427 4275 1551 -274 534 6982 2848 -880
428 4303 1563 -279 535 7005 2860 -887
429 4330 1575 -283 536 7029 2873 -894
430 4358 1587 -287 537 7052 2885 -902
431 4385 1598 -292 538 7075 2898 -909
432 4412 1610 -296 539 7098 2910 -916
433 4439 1622 -300 540 7122 2923 -923
434 4467 1634 -305 541 7145 2935 -930
135
435 4494 1646 -309 542 7168 2948 -937
436 4521 1657 -314 543 7191 2960 -944
437 4548 1669 -318 544 7214 2973 -951
438 4575 1681 -323 545 7237 2986 -959
439 4602 1693 -328 546 7260 2998 -966
440 4629 1705 -332 547 7283 3011 -973
441 4656 1716 -337 548 7306 3023 -980
442 4683 1728 -341 549 7329 3036 -988
443 4710 1740 -346 550 7352 3048 -995
444 4736 1752 -351 551 7375 3061 -1003
445 4763 1764 -356 552 7398 3074 -1010
446 4790 1776 -360 553 7420 3086 -1017
447 4816 1788 -365 554 7443 3099 -1025
448 4843 1800 -370 555 7466 3111 -1032
449 4869 1812 -375 556 7489 3124 -1040
450 4896 1823 -380 557 7511 3137 -1047
451 4922 1835 -385 558 7534 3149 -1055
452 4949 1847 -390 559 7557 3162 -1062
453 4975 1859 -395 560 7579 3175 -1070
454 5002 1871 -400 561 7602 3187 -1077
455 5028 1883 -405 562 7625 3200 -1085
456 5054 1895 -410 563 7647 3213 -1093
457 5080 1907 -415 564 7670 3225 -1100
458 5106 1919 -420 565 7692 3238 -1108
459 5132 1931 -425 566 7714 3251 -1116
460 5159 1943 -430 567 7737 3263 -1123
461 5185 1955 -435 568 7759 3276 -1131
462 5211 1967 -440 569 7782 3289 -1139
463 5236 1979 -446 570 7804 3302 -1147
464 5262 1991 -451 571 7826 3314 -1155
465 5288 2003 -456 572 7849 3327 -1162
466 5314 2015 -461 573 7871 3340 -1170
467 5340 2027 -467 574 7893 3352 -1178
468 5366 2039 -472 575 7915 3365 -1186
469 5391 2051 -478 576 7937 3378 -1194
470 5417 2063 -483 577 7960 3391 -1202
471 5442 2075 -488 578 7982 3404 -1210
472 5468 2087 -494 579 8004 3416 -1218
473 5494 2099 -499 580 8026 3429 -1226
474 5519 2111 -505 581 8048 3442 -1234
136
475 5545 2123 -510 582 8070 3455 -1242
476 5570 2135 -516 583 8092 3468 -1250
477 5595 2147 -521 584 8114 3480 -1258
478 5621 2160 -527 585 8136 3493 -1266
479 5646 2172 -533 586 8158 3506 -1274
480 5671 2184 -538 587 8180 3519 -1283
481 5696 2196 -544 588 8201 3532 -1291
482 5722 2208 -550 589 8223 3545 -1299
483 5747 2220 -555 590 8245 3557 -1307
484 5772 2232 -561 591 8267 3570 -1315
485 5797 2244 -567 592 8289 3583 -1324
486 5822 2257 -573 593 8310 3596 -1332
487 5847 2269 -579 594 8332 3609 -1340
488 5872 2281 -585 595 8354 3622 -1349
489 5897 2293 -590 596 8375 3635 -1357
490 5922 2305 -596 597 8397 3648 -1365
491 5947 2317 -602 598 8419 3660 -1374
492 5971 2330 -608 599 8440 3673 -1382
493 5996 2342 -614 600 8462 3686 -1391
494 6021 2354 -620 601 8483 3699 -1399
495 6046 2366 -626 602 8505 3712 -1408
496 6070 2379 -632 603 8526 3725 -1416
497 6095 2391 -638 604 8548 3738 -1425
498 6119 2403 -645 605 8569 3751 -1433
499 6144 2415 -651 606 8591 3764 -1442
500 6169 2427 -657 607 8612 3777 -1451
501 6193 2440 -663 608 8633 3790 -1459
502 6217 2452 -669 609 8655 3803 -1468
503 6242 2464 -675 610 8676 3816 -1476
504 6266 2477 -682 611 8697 3829 -1485
505 6291 2489 -688 612 8719 3842 -1494
506 6315 2501 -694 613 8740 3855 -1503
507 6339 2513 -701 614 8761 3868 -1511
508 6363 2526 -707 615 8782 3881 -1520
509 6388 2538 -713 616 8803 3894 -1529
510 6412 2550 -720 617 8825 3907 -1538
511 6436 2563 -726 618 8846 3920 -1547
512 6460 2575 -733 619 8867 3933 -1555
513 6484 2587 -739 620 8888 3946 -1564
514 6508 2600 -746 621 8909 3959 -1573
137
515 6532 2612 -752 622 8930 3972 -1582
516 6556 2624 -759 623 8951 3985 -1591
517 6580 2637 -765 62315 8954 3987 -1592
138
Appendix H
Table H1 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid I
state (29815-35415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 768 241 -011
299 023 007 000 328 794 249 -011
300 050 015 000 329 820 258 -012
301 077 023 000 330 846 266 -013
302 104 031 000 331 872 275 -014
303 131 039 000 332 898 284 -015
304 158 048 000 333 924 292 -016
305 185 056 -001 334 950 301 -016
306 212 064 -001 335 976 310 -017
307 239 072 -001 336 1002 318 -018
308 265 081 -001 337 1028 327 -019
309 292 089 -001 338 1053 336 -020
310 319 097 -002 339 1079 344 -021
311 345 105 -002 340 1105 353 -022
312 372 114 -002 341 1130 362 -024
313 399 122 -003 342 1156 371 -025
314 425 130 -003 343 1182 379 -026
315 452 139 -004 344 1207 388 -027
316 478 147 -004 345 1233 397 -028
317 505 156 -004 346 1258 406 -029
318 531 164 -005 347 1284 415 -031
319 558 172 -005 348 1309 424 -032
320 584 181 -006 349 1335 433 -033
321 611 189 -007 350 1360 441 -035
322 637 198 -007 351 1385 450 -036
323 663 206 -008 352 1411 459 -037
324 689 215 -008 353 1436 468 -039
325 716 223 -009 354 1461 477 -040
326 742 232 -010 35415 1465 478 -040
139
Table H2 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid 2
state (36215-37315K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36215 2387 777 -046
363 2408 809 -055
364 2432 817 -057
365 2457 826 -060
366 2481 835 -062
367 2506 843 -065
368 2530 852 -067
369 2555 861 -070
370 2579 870 -072
371 2604 879 -075
372 2628 888 -077
373 2653 898 -080
37315 2657 907 -083
Table H3 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in liquid
state (37915-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37915 2966 1025 -100 502 6174 2432 -667
380 2991 1034 -102 503 6198 2444 -674
381 3020 1045 -105 504 6222 2456 -680
382 3048 1056 -108 505 6246 2468 -686
383 3077 1067 -112 506 6270 2480 -692
384 3105 1078 -115 507 6294 2492 -699
385 3134 1089 -118 508 6317 2504 -705
386 3162 1100 -121 509 6341 2516 -711
387 3191 1111 -124 510 6365 2528 -718
140
388 3219 1122 -127 511 6388 2541 -724
389 3247 1133 -130 512 6412 2553 -730
390 3275 1144 -134 513 6436 2565 -737
391 3304 1155 -137 514 6459 2577 -743
392 3332 1166 -140 515 6483 2589 -750
393 3360 1177 -144 516 6506 2601 -756
394 3388 1188 -147 517 6530 2613 -763
395 3416 1199 -150 518 6553 2625 -769
396 3444 1210 -154 519 6577 2638 -776
397 3472 1221 -157 520 6600 2650 -782
398 3500 1232 -161 521 6624 2662 -789
399 3527 1243 -164 522 6647 2674 -796
400 3555 1254 -168 523 6670 2686 -802
401 3583 1265 -171 524 6694 2698 -809
402 3611 1276 -175 525 6717 2711 -816
403 3638 1287 -179 526 6740 2723 -822
404 3666 1299 -182 527 6763 2735 -829
405 3693 1310 -186 528 6786 2747 -836
406 3721 1321 -190 529 6810 2760 -843
407 3748 1332 -193 530 6833 2772 -850
408 3776 1343 -197 531 6856 2784 -856
409 3803 1354 -201 532 6879 2796 -863
410 3830 1366 -205 533 6902 2809 -870
411 3857 1377 -209 534 6925 2821 -877
412 3885 1388 -213 535 6948 2833 -884
413 3912 1399 -216 536 6971 2845 -891
414 3939 1410 -220 537 6994 2858 -898
415 3966 1422 -224 538 7017 2870 -905
416 3993 1433 -228 539 7040 2882 -912
417 4020 1444 -232 540 7063 2895 -919
418 4047 1455 -236 541 7086 2907 -926
419 4074 1467 -240 542 7108 2919 -933
420 4101 1478 -245 543 7131 2932 -940
421 4128 1489 -249 544 7154 2944 -947
422 4154 1500 -253 545 7177 2957 -955
423 4181 1512 -257 546 7199 2969 -962
424 4208 1523 -261 547 7222 2981 -969
425 4234 1534 -265 548 7245 2994 -976
426 4261 1546 -270 549 7267 3006 -984
427 4288 1557 -274 550 7290 3019 -991
141
428 4314 1568 -278 551 7313 3031 -998
429 4341 1580 -282 552 7335 3044 -1005
430 4367 1591 -287 553 7358 3056 -1013
431 4393 1602 -291 554 7380 3068 -1020
432 4420 1614 -296 555 7403 3081 -1028
433 4446 1625 -300 556 7425 3093 -1035
434 4472 1636 -305 557 7448 3106 -1042
435 4499 1648 -309 558 7470 3118 -1050
436 4525 1659 -314 559 7492 3131 -1057
437 4551 1671 -318 560 7515 3143 -1065
438 4577 1682 -323 561 7537 3156 -1072
439 4603 1694 -327 562 7560 3169 -1080
440 4629 1705 -332 563 7582 3181 -1087
441 4655 1716 -336 564 7604 3194 -1095
442 4681 1728 -341 565 7626 3206 -1103
443 4707 1739 -346 566 7649 3219 -1110
444 4733 1751 -351 567 7671 3231 -1118
445 4759 1762 -355 568 7693 3244 -1126
446 4785 1774 -360 569 7715 3257 -1133
447 4810 1785 -365 570 7737 3269 -1141
448 4836 1797 -370 571 7759 3282 -1149
449 4862 1808 -375 572 7782 3294 -1157
450 4888 1820 -379 573 7804 3307 -1164
451 4913 1832 -384 574 7826 3320 -1172
452 4939 1843 -389 575 7848 3332 -1180
453 4964 1855 -394 576 7870 3345 -1188
454 4990 1866 -399 577 7892 3358 -1196
455 5015 1878 -404 578 7914 3370 -1204
456 5041 1889 -409 579 7936 3383 -1212
457 5066 1901 -414 580 7957 3396 -1220
458 5092 1913 -419 581 7979 3408 -1228
459 5117 1924 -424 582 8001 3421 -1236
460 5142 1936 -430 583 8023 3434 -1244
461 5167 1947 -435 584 8045 3447 -1252
462 5193 1959 -440 585 8067 3459 -1260
463 5218 1971 -445 586 8088 3472 -1268
464 5243 1982 -450 587 8110 3485 -1276
465 5268 1994 -456 588 8132 3498 -1284
466 5293 2006 -461 589 8154 3510 -1292
467 5318 2017 -466 590 8175 3523 -1300
142
468 5343 2029 -472 591 8197 3536 -1308
469 5368 2041 -477 592 8219 3549 -1317
470 5393 2053 -482 593 8240 3562 -1325
471 5418 2064 -488 594 8262 3574 -1333
472 5443 2076 -493 595 8283 3587 -1341
473 5468 2088 -499 596 8305 3600 -1350
474 5493 2100 -504 597 8327 3613 -1358
475 5517 2111 -510 598 8348 3626 -1366
476 5542 2123 -515 599 8370 3639 -1375
477 5567 2135 -521 600 8391 3652 -1383
478 5592 2147 -526 601 8413 3664 -1391
479 5616 2158 -532 602 8434 3677 -1400
480 5641 2170 -537 603 8455 3690 -1408
481 5665 2182 -543 604 8477 3703 -1417
482 5690 2194 -549 605 8498 3716 -1425
483 5715 2206 -554 606 8520 3729 -1434
484 5739 2218 -560 607 8541 3742 -1442
485 5763 2229 -566 608 8562 3755 -1451
486 5788 2241 -572 609 8583 3768 -1459
487 5812 2253 -578 610 8605 3781 -1468
488 5837 2265 -583 611 8626 3794 -1477
489 5861 2277 -589 612 8647 3807 -1485
490 5885 2289 -595 613 8668 3820 -1494
491 5910 2301 -601 614 8690 3833 -1503
492 5934 2313 -607 615 8711 3846 -1511
493 5958 2324 -613 616 8732 3859 -1520
494 5982 2336 -619 617 8753 3872 -1529
495 6006 2348 -625 618 8774 3885 -1538
496 6030 2360 -631 619 8795 3898 -1546
497 6055 2372 -637 620 8816 3911 -1555
498 6079 2384 -643 621 8837 3924 -1564
499 6103 2396 -649 622 8858 3937 -1573
500 6127 2408 -655 623 8879 3950 -1582
501 6151 2420 -661 62315 8883 3952 -1583
143
Appendix I
Table I1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in solid state (29815-35315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 1171 366 -017
299 035 010 000 328 1211 379 -018
300 076 023 000 329 1250 392 -019
301 117 035 000 330 1290 405 -021
302 158 048 000 331 1330 418 -022
303 199 060 000 332 1369 431 -023
304 240 072 -001 333 1409 444 -025
305 281 085 -001 334 1448 458 -026
306 322 097 -001 335 1488 471 -028
307 363 110 -002 336 1527 484 -029
308 404 122 -002 337 1566 497 -031
309 445 135 -002 338 1605 510 -032
310 486 148 -003 339 1644 524 -034
311 526 160 -003 340 1683 537 -036
312 567 173 -004 341 1722 550 -037
313 608 186 -005 342 1761 563 -039
314 648 198 -005 343 1800 577 -041
315 689 211 -006 344 1839 590 -043
316 729 224 -007 345 1877 603 -044
317 770 237 -007 346 1916 617 -046
318 810 250 -008 347 1955 630 -048
319 850 262 -009 348 1993 643 -050
320 891 275 -010 349 2031 657 -052
321 931 288 -011 350 2070 670 -054
322 971 301 -012 351 2108 683 -056
323 1011 314 -013 352 2146 697 -059
324 1051 327 -014 353 2184 710 -061
325 1091 340 -015 35315 2190 712 -061
326 1131 353 -016
144
Table I2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in liquid state (39115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
39115 4413 1056 -191 508 8890 3521 -978
392 4450 1535 -195 509 8924 3538 -986
393 4492 1549 -200 510 8959 3556 -995
394 4535 1566 -204 511 8993 3574 -1004
395 4577 1583 -209 512 9027 3591 -1013
396 4620 1599 -213 513 9062 3609 -1022
397 4662 1616 -218 514 9096 3626 -1031
398 4704 1633 -223 515 9130 3644 -1041
399 4746 1650 -227 516 9164 3661 -1050
400 4789 1666 -232 517 9198 3679 -1059
401 4831 1683 -237 518 9232 3697 -1068
402 4872 1700 -242 519 9266 3714 -1077
403 4914 1717 -247 520 9300 3732 -1087
404 4956 1734 -252 521 9334 3750 -1096
405 4997 1751 -257 522 9368 3767 -1105
406 5039 1767 -262 523 9402 3785 -1115
407 5080 1784 -267 524 9435 3802 -1124
408 5122 1801 -272 525 9469 3820 -1134
409 5163 1818 -277 526 9503 3838 -1143
410 5204 1835 -282 527 9536 3855 -1152
411 5245 1852 -287 528 9570 3873 -1162
412 5286 1869 -293 529 9603 3891 -1172
413 5327 1885 -298 530 9637 3908 -1181
414 5368 1902 -303 531 9670 3926 -1191
415 5409 1919 -309 532 9703 3944 -1201
416 5450 1936 -314 533 9737 3962 -1210
417 5490 1953 -320 534 9770 3979 -1220
418 5531 1970 -325 535 9803 3997 -1230
419 5571 1987 -331 536 9836 4015 -1240
420 5612 2004 -336 537 9869 4032 -1249
421 5652 2021 -342 538 9902 4050 -1259
145
422 5692 2038 -347 539 9935 4068 -1269
423 5732 2055 -353 540 9968 4086 -1279
424 5772 2072 -359 541 10001 4104 -1289
425 5812 2089 -365 542 10034 4121 -1299
426 5852 2106 -371 543 10066 4139 -1309
427 5892 2123 -376 544 10099 4157 -1319
428 5932 2140 -382 545 10132 4175 -1329
429 5971 2157 -388 546 10165 4192 -1340
430 6011 2174 -394 547 10197 4210 -1350
431 6051 2191 -400 548 10230 4228 -1360
432 6090 2208 -406 549 10262 4246 -1370
433 6129 2225 -412 550 10295 4264 -1380
434 6169 2242 -419 551 10327 4282 -1391
435 6208 2259 -425 552 10359 4299 -1401
436 6247 2276 -431 553 10392 4317 -1411
437 6286 2293 -437 554 10424 4335 -1422
438 6325 2310 -444 555 10456 4353 -1432
439 6364 2327 -450 556 10488 4371 -1443
440 6403 2344 -456 557 10520 4389 -1453
441 6442 2361 -463 558 10553 4407 -1464
442 6480 2378 -469 559 10585 4424 -1474
443 6519 2395 -476 560 10617 4442 -1485
444 6557 2412 -482 561 10648 4460 -1496
445 6596 2429 -489 562 10680 4478 -1506
446 6634 2446 -495 563 10712 4496 -1517
447 6673 2464 -502 564 10744 4514 -1528
448 6711 2481 -509 565 10776 4532 -1538
449 6749 2498 -515 566 10808 4550 -1549
450 6787 2515 -522 567 10839 4568 -1560
451 6825 2532 -529 568 10871 4586 -1571
452 6863 2549 -536 569 10902 4604 -1582
453 6901 2566 -543 570 10934 4622 -1593
454 6939 2584 -550 571 10965 4640 -1604
455 6977 2601 -557 572 10997 4658 -1615
456 7015 2618 -564 573 11028 4676 -1626
457 7052 2635 -571 574 11060 4694 -1637
458 7090 2652 -578 575 11091 4712 -1648
459 7128 2670 -585 576 11122 4730 -1659
460 7165 2687 -592 577 11154 4748 -1670
461 7202 2704 -599 578 11185 4766 -1681
146
462 7240 2721 -606 579 11216 4784 -1692
463 7277 2738 -614 580 11247 4802 -1704
464 7314 2756 -621 581 11278 4820 -1715
465 7351 2773 -628 582 11309 4838 -1726
466 7388 2790 -636 583 11340 4856 -1737
467 7425 2807 -643 584 11371 4874 -1749
468 7462 2825 -650 585 11402 4892 -1760
469 7499 2842 -658 586 11433 4910 -1772
470 7536 2859 -665 587 11464 4928 -1783
471 7573 2877 -673 588 11495 4946 -1794
472 7609 2894 -680 589 11525 4964 -1806
473 7646 2911 -688 590 11556 4982 -1817
474 7682 2928 -696 591 11587 5001 -1829
475 7719 2946 -703 592 11617 5019 -1841
476 7755 2963 -711 593 11648 5037 -1852
477 7792 2980 -719 594 11678 5055 -1864
478 7828 2998 -727 595 11709 5073 -1876
479 7864 3015 -735 596 11739 5091 -1887
480 7900 3032 -742 597 11770 5109 -1899
481 7937 3050 -750 598 11800 5128 -1911
482 7973 3067 -758 599 11831 5146 -1923
483 8009 3084 -766 600 11861 5164 -1935
484 8045 3102 -774 601 11891 5182 -1946
485 8080 3119 -782 602 11921 5200 -1958
486 8116 3137 -791 603 11952 5218 -1970
487 8152 3154 -799 604 11982 5237 -1982
488 8188 3171 -807 605 12012 5255 -1994
489 8223 3189 -815 606 12042 5273 -2006
490 8259 3206 -823 607 12072 5291 -2018
491 8294 3224 -832 608 12102 5309 -2030
492 8330 3241 -840 609 12132 5328 -2042
493 8365 3259 -848 610 12162 5346 -2055
494 8401 3276 -857 611 12192 5364 -2067
495 8436 3293 -865 612 12222 5382 -2079
496 8471 3311 -873 613 12252 5401 -2091
497 8506 3328 -882 614 12281 5419 -2103
498 8542 3346 -890 615 12311 5437 -2116
499 8577 3363 -899 616 12341 5456 -2128
500 8612 3381 -908 617 12370 5474 -2140
501 8647 3398 -916 618 12400 5492 -2153
147
502 8681 3416 -925 619 12430 5510 -2165
503 8716 3433 -934 620 12459 5529 -2178
504 8751 3451 -942 621 12489 5547 -2190
505 8786 3468 -951 622 12518 5565 -2203
506 8820 3486 -960 623 12548 5584 -2215
507 8855 3503 -969 62315 12552 5602 -2217
ix
63 Fusion and solid phase transition temperature for individual salts 42
64 Melting points of candidate systems as function of temperatures 51
65 Calibration data of heat capacities with different samples 52
66 Heat capacity of selected new TES molten salt mixtures 54
67 Change of Gibbs energy values at 62315K for molten salt systems 85
68 Calibration of density measurements with different pure nitrate salts 86
69 Coefficient of A and B for density determination of salt 1 to salt 9 87
610 Extrapolated value of density and heat capacity at 500oC of salt 1 to salt 9 91
611 Energy density of salt 1 to salt 9 compare to solar salt 92
612 Gravimetric storage densities for solar salt and new molten salts 93
x
LIST OF FIGURES
11 Theoretical and engineering energy conversion efficiency as function of temperature 6
12 Gravimetric storage density for different energy storage systems
as function of temperature 8
51 Photography of set-up for DSC equipment 31
61 Melting point calibration with indium sample 34
62 Melting point calibration with KNO3 sample 35
63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt 36
64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt 37
65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt 37
66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt 38
67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt 38
68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt 39
69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt 39
610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt 40
611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN Salt 40
612 DSC plot of 698wt KNO3 -302wt NaNO2 binary system 43
xi
613 DSC plot of 270wt NaNO3-730wt KNO3 binary system 45
614 DSC plot of 458wtLiNO3-542wtKNO3 binary system 45
615 DSC plot of 460wt NaNO3-540wt KNO3 binary system 46
616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 20oCmin heating rate 47
616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 5oCmin heating rate 48
617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 5oCmin heating rate 49
617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 20oCmin heating rate 49
618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system
as function of temperature 53
619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K 54
620 Change of Gibbs energy as function of temperature for molten salt systems 85
621 The densities of the salt 1 to salt 5 as function of temperature 87
622 The densities of the salt 6 to salt 9 as function of temperature 89
623 Densities of the salt 1 salt 2 as function of temperature compared to
the equimolar NaNO3-KNO3 binary system and pure KNO3 90
624 Gravimetric storage density comparison of different energy storage
xii
systems as function of temperature 93
1
CHAPTER 1
INTRODUCTION
Renewable energy sources such as wind solar water power geothermal and biomass are
playing more and more significant role in our energy supply Because the cheap cost and infinite
amount of energy storage inside the resource solar energy is emphasized since 20th
century and
viewed as promising alternative method to satisfy the large energy consumption every day in the
world reduce the emission of carbon and strengthen the economy
The wind energy was used as a clean energy to generate electricity back to late 19th
century
However this renewable energy source was not emphasized due to the cheap price of fossil fuel
The re-emergence happened in mid 1950s when the amount of traditional energy source was
found apparently decrease The development of wind energy usage continued and in 1990 the
first mega-watt wind turbine was launched which was viewed as a symbol of shift to large scale
wind energy utilization [1-2] The modern application of wind energy mainly relies on wind
turbine On the basis of aerodynamic wind turbine generates certain net positive torque on
rotating shaft and then converts the mechanical power to electrical power As an electrical power
generator wind turbine is connected to some electrical network to transport the electricity to
battery charging utilities residential power systems and large scale energy consuming systems
In general most of wind turbines are small scale and can only generate 10KW electrical power
Only few of the wind turbine systems operate with capacity as large as 5MW Although the
usage of wind energy can reduce the emission of carbon oxide the noise pollution and high cost
2
limit its large scale application Since the wind is not transportable the electrical energy can only
be generated where the wind blows which also decrease the flexibility of wind energy
Water power is another term of alternative power supply and it was used for irrigation
operating machines like watermill even before the development of electrical power The modern
application of water power is to generate electricity by using the gravitational force of falling or
flowing water These days there are various ways for the water power application The most
traditional method is to store the water in dam and generate electricity by converting the
potential energy pump storage is a different way to utilize water power and can change its
output depending on the energy demand by moving water between reservoirs at different
elevations In the low energy demand period excess energy is used to lift water to the higher
level while in the peak period of energy demand the water is released back to the lower
elevation through water turbine Water power can also be converted by taking advantage of
naturally raise and fall of tide to satisfy the demand of electrical energy consumption [3]
Although the usage of water power can reduce the emission of carbon dioxide and cost it will
destroy the ecosystem because of the large land required for construction There will be methane
emission from the reservoir the potential failure hazard of dam is also a fatal issue and flow
shortage caused by drought may also create serious problem As result of that water power
technique is not a long-term alternative choice
Geothermal energy is the energy form generated inside the earth At the very beginning of
the planet formation a large amount of thermal energy was stored from the radioactive decay of
minerals volcanic activity and solar energy absorption Because of the temperature difference
3
between the core and the surface of planet the thermal energy stored inside the earth is driven to
the outer surface in the form of heat This form of renewable energy source can be applied to
generate electrical power and heat for industrial space and agricultural applications
Theoretically the deposited amount of geothermal energy is adequate to supply the energy
consumption in the world However most of the geothermal energy is stored deeply near the
core of the earth the deep drilling and exploration of geothermal energy is very expensive and
limits the large-scale use of this renewable energy source [4]
Biomass is a renewable energy source used to generate heat or electricity with living or
recently living organism such as wood waste (hydrogen) gas and alcohol fuels The biomass
energy can be converted to electrical energy by thermal method such as combustion pyrolysis
and gasification Several specific chemical processes may also be able to convert the biomass
energy to other forms The main problem arise from application of biomass is air pollution which
contains carbon monoxide NOx (nitrogen oxides) VOCs (volatile organic compounds)
particulates and other pollutants And the level of air pollution to some extent is even above that
of traditional fuel resource Some other possible issue like transportation and sink of carbon also
limit the wide usage of this type of alternative energy [5]
Among all the renewable energy sources solar energy is the most suitable alternative
energy for our future life It is clean cheap abundant without any noise air pollution no
transportation issue and easy to be obtained anywhere in the earth Inside the core of the Sun
hydrogen fuses into helium with a rate of 7times1011
kgs and generates very powerful nucleation
power This type of nucleation explosion creates ultra high temperature in the core of the Sun
4
which reaches approximately 16 million K degrees Although the Sun is not perfectly black body
it still radiates abundant power with the energy density as 16times107 wattsm
2 [6-7] Because of the
enough amount of hydrogen underneath the surface of the Sun the radiation given arise of from
the nucleation explosion can continue at least 5 million years with the same rate and strength
The energy reaching the earth is vastly reduced mainly caused by the absorption and spreading
of the radiation It is easily to understand that there are numerous amorphous objects all around
the entire universe which can absorb certain portion of the radiation for the Sun Moreover the
light generated from the spherical object such as the Sun fills all the available space between the
origin to the destination Even though the energy will not be lost in the travelling process due to
the long distance between the Sun to the earth the surface area of the sphere which is formed
with the Sun as center and the distance as radius is much larger than that of the earth As the
result of that only 1340Wm2 finally reaches the upmost surface of the earth Even though the
final amount of the received solar energy is very small compared to that is initially radiated from
the Sun the average daily solar radiation falling on one area in the continental United States is
equivalent in total energy content to 11 barrels of oil In summary the solar energy itself is
relatively unlimited useful clean and almost unexploited energy and definitely can behave as
the promising mean for the future energy supply [8]
There are several different methods to take advantage of the solar energy and all the
methods can be distinguished into three group solar parabolic trough solar tower and solar dish
Parabolic trough is constructed by silver coated parabolic mirror and there is a Dewar tube going
through the length of the mirror and set on the focal point all the radiation is concentrated on the
tube and transfer by heat transfer fluid to the thermal energy storage unit Solar tower are used to
5
capture solar energy with thousands of mirrors and focus the concentrated sunlight to the top of
the tower which is located in the middle of the heliostats The thermal energy storage medium
within the tower was heated to high temperature and transferred to thermal energy storage tank
and eventually sent to steam pump The solar dish is built with a large reflective parabolic dish
which concentrates all the received sunlight to one spot There is normally a receiver located on
the focal point and transform the solar energy to other forms of useful energy The working
upper limit temperature of solar parabolic trough system is the lowest among these three systems
normally its maximum working temperature is within the range from 400-500oC the solar tower
has higher maximum working temperature which ranges from 500-1000oC the solar dish has the
highest working upper limit temperature which reaches 700-1200oC [9]
The energy conversion efficiency is the most concerned parameter in the solar energy
storage application and the theoretical and real engineering efficiency are given in fig 11 as
function of temperature The theoretical conversion efficiency can be up to 80 while in real
application the value is always less than 70 regardless of collectors The actual efficiency
increases with temperature in the whole working temperature As a result of that the thermal
energy storage materials in solar parabolic trough for instance should be able to work stably at
the upper limit temperature of this type of collection system which is 500oC to ensure the highest
efficiency [9 10]
6
Fig 11 Theoretical and engineering energy conversion efficiency as function of
temperature
Solar energy can be stored in three major forms sensible heat latent heat and
thermochemical heat Sensible heat storage was utilized based on the heat capacity and the
change as function of temperature of storage materials in the charging and discharging process
which correspond to the absorbing and withdrawing energy processes respectively The sensible
heat stored from the melting point to the maximum working temperature can be expressed by
equation 1 [9]
[1]
Where m is the mass of storage material Tmp and TH are melting point temperature and high
temperature in the same phase respectively Cp(T) is the heat capacity at different temperature
Because the sensible heat storage materials remain in a single phase in the working temperature
range the charging and discharging processes are completely reversible for unlimited cycles
7
Latent heat storage is operated by absorbing and withdrawing energy in the charging and
discharging processes accompanied with fusion of materials [9] The latent heat collected
throughout the working temperature range can be expressed by equation 2 as following
[2]
Where T is temperature in solid state Tmp is melting point temperature of storage material TH is
the high temperature in liquid state and is enthalpy of fusion
Thermochemical heat storage is based on the heat capacity and its change as function of
temperature accompanied with chemical reaction The thermochemical heat collected throughout
the working temperature range can be expressed by equation 3
[3]
Where TL is the low temperature before the reaction TR is the reaction temperature and
is the enthalpy of chemical reaction Because of the destruction of the chemical bonds
in the reaction process the charging and discharging process cannot be completely reversible
which reduces the stability and recyclability of storage operation [10]
Sensible energy storage method is chosen to ensure the efficient usage of solar energy for
parabolic trough system of which the maximum working temperature ranges from 400-500oC
Different from thermochemical heat storage the sensible heat storage can achieve completely
reversible working condition under unlimited cycles Also fig 12 illustrates that the sensible
heat storage materials mainly work in the working temperature range for parabolic trough system
8
and the gravimetric energy storage densities of sensible heat is higher than that of latent heat
materials [9 -11]
Fig 12 Gravimetric storage density for different energy storage systems as function of
temperature
Various materials are chosen to serve as thermal energy storage fluid for sensible heat
such as water thermal oil ionic liquid and molten salt [12] The properties of different heat
transfer fluid determine the performance of solar energy heating system In these days the
efficiency and cost of output of electrical power mainly relies on the parabolic trough solar
power plant and the thermal storage fluid [12] A large investment cost is needed to dispatch
100MW to 200MW energy by consuming the energy transfer fluids Given by this situation the
development of new thermal storage fluid with higher thermal energy storage density is
paramount to lower the expense for generating energy and a lot of effect has been put on design
of new systems [13-16]
9
Water is commonly used as heat transfer and thermal energy storage fluid in industry
because of its low cost high heat capacity and high thermal conductivity However the
limitation for using this medium is also obvious that the temperature range within which the
liquid state can be assured is too small It is well know that water can only serve as thermal
energy storage liquid above the freezing point 0oC and below the boiling temperature 100
oC In
practical experiment the actual temperature range is even less than 100oC because of the large
amount of weight loss near the boiling temperature due to the high vapor pressure Water is
possible to work above 100oC only if high pressure is also applied to avoid the phase
transformation but the cost will be highly increased Accordingly water is only suitable to work
in low temperature below 100oC
Thermal oils are also being used in the parabolic trough solar power plant and have very
low melting point as low as 12oC [17 18] However the application of the oil for the thermal
energy storage liquid is limited by some disadvantages from the physic-chemical properties The
upper limit for this oil is only 300oC and above that the liquid state cannot be maintained
Moreover the low thermal decomposition temperature low density and low heat capacity result
in limited thermal energy storage capacity Since the working temperature range is so narrow the
rankie cycle efficiency is reduced when using the synthetic oil and the cost for generating power
is considered to be very expensive [19 20]
Ionic liquid is another medium served as thermal energy storage fluid The liquid
temperature range of ionic liquid is large which is one of the main advantages of this type of
material The high heat capacity and density ensure the efficiency of thermal energy storage of
10
ionic liquid What‟s more the excellent chemical stability and little vapor pressure increase the
lifetime [21-24] However as a result of the very serve corrosion problem to the liquid container
and the high cost the usage of ionic liquid is still limited
Considering various relative physic-chemical properties of thermal energy storage system
molten salts have been proposed as a suitable group for a wide temperature range application
They are being emphasized in the solar energy applications because of their low melting point
and high upper limit which can increase the stable working range The high heat capacity
increases the thermal energy storage density of the heat storage system excellent thermal
stability and negligible vapor pressure ensure the steadiness of cyclic repeating in the lifetime
[25] low viscosity strengths the mobility and efficiency of the thermal storage liquid low
utilization cost reduce the investment and protect the economy The liquidus temperature range
of the molten salt varies from 150-600oC combination of various salts can bring the melting
down and further increase the working temperature range Due to these properties molten salts
can be excellent thermal energy storage fluid in the solar power generation system
11
CHAPTER 2
LITERATURE REVIEW
Several physical and thermodynamic properties of thermal energy storage fluid play
significant role in determining the efficiency and performance of solar energy storage systems In
order to evaluate the feasibility of systems the physic-chemical properties of several molten salts
should be reviewed The three determining parameter which directly affect the thermal energy
storage capacity in systems are melting point heat capacity and density
There are large amount of melting point data available in the literature for various molten
salt system in previous literatures while those with melting point less than 120oC is very limited
All the previous study on molten salt system revealed that five group of molten salts are
emphasized and commonly used alkai or alkaline nitrates carbonates sulphates chloride and
hydroxides Although most of the systems have the same group of cation the melting point
varies a lot from one to anther due to the different effect of anions
21 Melting point
The melting points of individual and multi-component nitratenitrite systems are listed in
Table 21[26-31] Among those systems solar salt (NaNO3KNO3 6040) is the thermal energy
storage medium which is currently being used with the freezing point of 221oC [27] Although
the melting point for this system is highest in all the candidate mixtures in this group the lowest
12
combined compound cost makes it widely used in solar energy storage field Another ternary
system HITEC which contains NaNO3 KNO3 and NaNO2 has freezing point of 141 oC [28]
This combination brings the melting point down but the lack of combination of optimum features
limits its further application [29] Some mixtures such as LiNO3-Ca(NO3)2-KNO3 are not often
utilized because they increase the compound cost at the same time of lowering the melting point
to around 120oC [30] moreover the decreased melting point is still high compared to the
organic oil There are also several systems have the melting points less than 100oC or even 60
oC
they are not used in the parabolic trough solar power plant due to the decomposition of some
components during high temperature [31]
Table 21 Melting point of various nitrate salt systems
Compound Melting Point (ordmC)
LiNO3 253
NaNO3 307
KNO3 334
Ca(NO3)2 561
Sr(NO3)2 570
Ba(NO3)2 590
NaNO3-NaNO2 221
NaNO3-NaNO2-KNO3 141
NaNO3-KNO3-CaNO3 133
LiNO3-KNO3-NaNO3 120
KNO3-CaNO3-LiNO3 117
LiNO3-KNO3-NHNO3 92
KNO3-NHNO3-AgNO3 52
The melting points of individual and multi-component carbonate systems are listed in
Table 22 [26 32 33] Different from the nitrate salts the melting points for both the individual
13
and multi-component carbonate systems are on the higher side The lowest melting point is
achieved with lithium sodium and potassium carbonate ternary system whose melting point is
still 277oC higher than that of the nitrate ternary system with the same cations [32] Besides
because of the thermal decomposition issue the choice of component involved in the multi-
component carbonate systems is limited Some salt like CaCO3 doesn‟t have stable form at high
temperature and the lack of multi-component system reduces the chance of the synthesis of low
melting point salt mixtures Even though this group of salt is not thermally stable and the
working temperature range is relatively small it is still viewed as possible candidate working at
high temperature due to its low price
Table 22 Melting point of various carbonate salt systems
Compound Melting Point (ordmC)
Li2CO3 732
Na2CO3 858
K2CO3 900
MgCO3 990
Na2CO3-K2CO3 710
Li2CO3-Na2CO3 496
Li2CO3-K2CO3 488
Li2CO3-K2CO3-Na2CO3 397
Alkali and Alkaline fluoridechloride salts are also selected as one possible choice as the
thermal energy storage fluid and the melting point examined from previous literatures are given
in table 23 [34-38] A lot of study has been done for this group of salt and the melting points
were found in the same range as the carbonate group And for the pure salt metal chloride salts
have lower melting point than metal fluoride ones
14
Table 23 Melting point of various fluoridechloride salt systems
Compound Melting Point (ordmC)
LiF 849
NaF 996
KF 858
LiCl 610
NaCl 801
KCl 771
LiF-KF 493
LiF-NaF 652
LiCl-KF 487
LiF-NaF-KF 454
LiF-NaF-KF-MgF2 449
LiF-KF-BaF2 320
LiF-KF-CsF-RbF 256
Several studies were also conducted to determine the melting point of molten hydroxide
salts and the results are shown in Table24 The data of pure salts and multi-component mixtures
merely in this group were not much determined in the literatures Generally they are mixed with
other groups of anion and form some low melting point salt mixtures [39-42] On the basis of the
previous literature data alkali hydroxide salts and their mixture with salts in other groups have
relatively lower melting point compared with pure carbonate and fluoride chloride group salt
mixtures Most of the melting points given in Table 4 are lower than 300oC sodium potassium
hydroxide binary mixture even reaches the melting point below 200oC Accordingly relatively
large temperature range can be obtained by using hydroxide salt mixtures or adding them as
additive
15
Table 24 Melting point of various hydroixde salt systems
Compound Melting Point (ordmC)
LiOH-LiF 427
NaOH-KOH 170
LiOH-NaOH 213
NaOH-NaNO2 232
NaOH-NaNO3 237
NaOH-NaCl-NaNO3 242
NaOH-NaCl-Na2CO3 282
22 Density
For the solar energy storage system density for the thermal energy storage fluid is also
essential parameter The density is needed for the size calculation as function of temperature and
assessing for the thermal stability of thermoclines Besides density as function of temperature is
used to evaluate the volume change in the process of freezing which contributes to potential
stress
Alkalialkaline nitrate salts were studied very much about their density as function of
temperature All the results indicate that the density was decreased linearly as temperature
increases and any specific density value in the molten state can be expressed by equation as
equation 4
= A-BT [4]
Where (gcm3) is the density of salt A (gcm
3) is the initial density value at 0
oC and B
(mgcm3degC) is the density change slope as function of temperature The coefficients are shown in
16
Table 25 for the nitrate group molten salts Among these systems pure sodium nitrate has the
largest value which reveals the high initial density value at low temperature [43] Conversely
lithium nitrate has the lowest value while it presents the smallest decrease trend as temperature
increases [44] The densities and A B values of multi-component nitrate salts were included in
the range of those two salts discussed above
Table 25 Density coefficients A and B of nitrate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiNO3 1922 0556
NaNO3 2334 0767
KNO3 2127 0760
NaNO3-KNO3 2134 0773
KNO3-CaNO3-LiNO3 2172 0735
LiNO3-KNO3-NaNO3 2083 0715
Several experiments were also conducted to measure the density as function of temperature
for the individual and multi-component carbonate salt systems The density of the carbonate salt
also follow the same trend as that of nitrate salt and the temperature dependence of density
followed the linear equation as discussed above It is observed that all the carbonate salts have
higher initial density coefficient A than the nitrate salt The largest value is reached to 2511 and
even the lowest value in this group is greater than the maximum A of nitrate group [45-49]
What‟s more the regression slope coefficient B of carbonate salt is lower compared to that of the
nitrate salt group Accordingly the salts in this group present larger density in the molten state
and the density coefficient A and B are given in Table 26
17
Table 26 Density coefficients A and B of carbonate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
Li2CO3 2303 0532
Na2CO3 2350 0448
Na2CO3-K2CO3 2473 0483
Li2CO3-K2CO3 2511 0599
Li2CO3-Na2CO3 2456 0519
Li2CO3-Na2CO3-K2CO3 2364 0544
Density of metal fluoride and chloride molten salt were also examined and present similar
regression trend as temperature increases The linear temperature dependence is also expressed
by the same equation On the basis of previous literature data the pure chloride salt shows lower
density than the fluoride salt with the same cation in the molten state [49] What‟s more the
sodium halide salt has the largest density value while the lithium halide salt has the lowest value
which is very similar to the nitrate group salt The density determination coefficient A and B are
given in Table27
Table 27 Density coefficients A and B of chloridefluoride salts
Compound A(gcm3) Btimes103(gcm
3degC)
LiCl 1766 0432
NaCl 1991 0543
KCl 1976 0583
LiF 2226 0490
NaF 2581 0636
KF 2469 0651
LiF-NaF 2520 0818
LiCl-NaF-KCl 2436 0742
LiF-NaF-MgF 2240 0701
18
The density measurement of hydroxide was not conducted as much as those three anion
groups discussed above Only few data of density is available for the alkali hydroxide salt when
added into other salt systems and temperature dependence also follows the linear regression
trend [32 41] The density determination coefficient A and B are given in Table 28
Table 28 Density coefficients A and B of molten salt mixture with hydroxide salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiCl-LiOH 16 0443
LiF-LiOH 165 0471
23 Heat capacity
In the heating process the temperature of solar energy storage molten salt is increase by
absorbing energy from the solar radiation Conversely the same amount of heat is released and
applied to heating system in the process of cooling Heat capacity is the amount of heat required
to increase the temperature of certain material by 1 oC and can be viewed as the directly relevant
parameter to the energy storage ability To some extent the large heat capacity assures the
efficiency of the application of solar energy storage materials
The heat capacity of alkalialkaline nitrate salt was investigated for both individual and
multi-component system in the previous literature To simplify the comparison only the heat
capacity value at 500oC is shown in all the following tables In the liquid state the heat capacity
increases with temperature following linear equation and the increasing slope is as small as 10-5
to 10-4
[50 51] Among those alkali nitrate salt systems lithium nitrate has the largest heat
19
capacity at 500oC while potassium nitrate presents the lowest value at that temperature In table
29 the heat capacity results at the selected temperature in literature are given
Table 29 Heat capacity of alkali nitrate salt at 500oC
Compound Heat capacity(JgK)
LiNO3 2175
NaNO3 1686
KNO3 1400
NaNO3-KNO3 1533
LiNO3-KNO3 1642
LiNO3-KNO3-NaNO3 1681
For the carbonate salt systems in the molten state the heat capacity is almost constant and
almost independent with temperature [32 33] Same as the nitrate group salts the heat capacity
for pure carbonate salt decreases as the atomic number of the alkali element increases which
means the value for lithium carbonate is the largest and that of potassium carbonate is the
smallest Generally the heat capacity value for carbonate in molten state is larger than that in
solid state However the sodium-potassium carbonate binary system is an exception for which
the heat capacity in solid state is larger than liquid state In table 210 the heat capacity results of
carbonate salts at the selected temperature in literature are given
Table 210 Heat capacity of alkali carbonate salt at 500oC
Compound Heat Capacity(JgK)
Li2CO3 250
Na2CO3 178
K2CO3 151
Na2CO3-K2CO3 157
20
Li2CO3-K2CO3 160
Li2CO3-Na2CO3 209
Li2CO3-K2CO3-Na2CO3 163
The heat capacity of fluoridechloride salt was measured in several literature and found
that for the pure salt the lithium halide has the biggest heat capacity data in the molten state
while the potassium halides shows the lowest heat capacity value Similar to the carbonate group
the heat capacity value of fluoridechloride salt varies little with temperature in the liquid state
[32 33] The values at 500oC for the alkalialkaline halides are shown in Table 211
Table 211 Heat capacity of fluoridechloride salt at 500oC
Compound Heat Capacity (JgK)
LiCl 148
NaCl 115
KCl 090
LiF-KF 163
NaCl-MgCl2 100
LiF-NaF-KF 155
KCl-MgCl2-CaCl2 092
The heat capacity of pure and multi-component hydroxide salt systems is limited in the
previous literature and the values in the liquid state follow linear equation which is observed for
all the molten salt discussed above [52] The values at 500oC for the alkalialkaline halides are
shown in Table 212
21
Table 212 Heat capacity of hydroxide salt at 500oC
Compound Heat Capacity(JgK)
NaOH 188
LiOH-NaOH 221
NaOH-KOH 182
In summary on the basis of comparison of various physic-chemical properties molten
nitrate slats have relatively low melting point excellent working temperature range reasonable
density and high heat capacity As the result of that molten nitrate salt is suitable to be applied as
the thermal energy storage fluid in the solar energy storage system
22
CHAPTER 3
OBJECTIVES
Based on review of previous literature data it is found that there are several disadvantages
such as the high melting point relatively low density value or poor heat capacity in liquid state
which limit the application of molten salt in certain groups in solar thermal energy storage
system Conversely alkalialkaline nitrate salt is considered as the suitable choice and proposed
as the thermal energy storage liquid for high temperature
Currently the used thermal energy storage liquid is NaNO3 (60mol)-KNO3 (40mol)
binary system (solar salt) which has the melting point at 221oC [30] Although the melting point
for this salt mixture is not the lowest it is still emphasized because of its low investment cost
However there are some drawbacks for this binary nitrate mixture The main disadvantage is
the high melting point In evenings or in winter the molten salt can easily freeze and block the
pipeline As a result of that some auxiliary cost should be added to overcome this problem and
the total investment will be increased
Development and synthesis of newer molten salt mixtures with freezing point lower than
those currently used for thermal energy storage applications is necessary for higher efficiency of
utilization of solar energy and getting rid of any unnecessary cost The approach to develop
lower freezing point molten salt mixtures is by the prediction of new eutectic mixtures and also
23
by the development of new nitrate compounds Besides these two most well known systems
several other mixtures were also studied Preliminary evaluation of several new molten salt flux
systems based on requirements for thermal energy storage systems mainly including freezing
point density heat capacity viscosity and thermal energy storage density The promising
candidate low melting point molten salt system should satisfy the requirements that eutectic
melting temperatures are lower than 220oC and the thermal energy storage densities are higher
than binary solar salt It is known that the melting point can be lowered by the addition of one or
more ABNO3 nitrate compounds where A and B are cations Consequently several multi-
component systems which have more constituent salts than solar salt were came up with and
studied with little fundamental data on the physic-chemical properties at the required operating
conditions available at present
In this thesis the new systems with simulated eutectic compositions were tested for their
experimental melting points heat capacities using the Differential Scanning Calorimetry (DSC)
technique which is considered to be the accurate instrument for thermodynamic data analysis
[53-59] Some significant thermodynamic properties such as heat capacity enthalpy and entropy
and Gibbs energy were calculated in the thesis to evaluate the energy change of the system in the
phase change process and the potential of being applied in the parabolic trough solar power plant
The energy density was obtained by using the experimental measured density and heat capacity
of the mixtures in molten state Finally 9 down-selected systems were present and discussed
24
CHAPTER 4
THERMODYNAMIC MODELING OF SALT SYSTEMS
41 Thermodynamic modeling
To lower the melting point of solar energy storage system multi-component system is
applicable Thermodynamic model was introduced to predict the eutectic temperature of salt
systems based on the Gibbs energies of fusion of individual salt and that of mixing of constituent
binary systems At the eutectic temperature the Gibbs energies in the liquid state and solid state
of salt are equal In thermodynamics Gibbs energy of fusion can be expressed by the equation
given as follows
G = H-TS [5]
Where H is the change of enthalpy of fusion and S is the change of entropy of fusion Equally
the entropy change of fusion can be expressed by differentiating G and the equation is given
[6]
It is known that the change in entropy can be expressed in terms of change in heat capacity in the
melting process as
[7]
25
If the change of heat capacity is assume to be independent of temperature the integral of
from Tm to T can be shown as
[8]
where Sm is the entropy of fusion at the melting point which is equal to Accordingly
Eq8 can be rewritten as
[9]
Substituting Eq 9 in Eq 6 and integrating the equation from Tm to T we get
[10]
Eq 10 illustrates that by using the change of heat capacity melting point and enthalpy of fusion
the Gibbs energy change at any temperature can be obtained
The standard Gibbs energy of fusion of a salt bdquo1‟ can be expressed in terms of the activity
of the salt as
[11]
where is the molar excess Gibbs energy and X1 is the molefraction of the salt bdquo1‟ Gibbs
energy of fusion at any give temperature T is expressed by Eq 7 in terms of its molefraction and
partial molar excess Gibbs energy
26
Take LiNO3-NaNO3-KNO3 as an example in which the integral molar excess Gibbs energy is
composed of the summation of the Gibbs energies of three constituent binary system and one
ternary The expression of the integral excess Gibbs energy is given by Eq12
[12]
Gibbs energies of the three constituent binary systems LiNO3-NaNO3 LiNO3-KNO3 and
NaNO3-KNO3 of the LiNO3-NaNO3-KNO3 ternary system are taken from the literature [48 49]
The Gibbs energies of mixing or the integral excess Gibbs energies of the three constituent
binary systems of the LiNO3-NaNO3-KNO3 ternary system are given below
LiNO3-NaNO3 Binary System
Jmol [13]
LiNO3-KNO3 Binary System
Jmol [14]
NaNO3-KNO3 Binary System
Jmol [15]
When assume the intergral excess Gibbs energy of to be zero the excess Gibbs energy in
the ternary system can be expressed by the summation of three constituent binary systems
[16]
27
Generally the partial molar excess Gibbs energies are reduced from the integral molar
excess Gibbs energy and can be expressed by the generalized equation for certain ldquomrdquo
component salt as
[17]
In the ternary system the i value equals to 12 and 3 and the partial molar excess Gibbs energy
of mixing for each component can be expressed as follows
[18]
[19]
[20]
Based on Eq 7 and the partial molar excess Gibbs energy of individual component the
Gibbs energy in the fusion can be expressed as Eq21- 23
[21]
[22]
[23]
42 Calculations
The fusion of the ternary salt system is defined by solutions of Eq 21-Eq 23 Newton-
Raphson method can be used to solve these three non-linear equations by linearizing the non-
linear equations using the Taylor series and truncating the series to first order derivatives
28
Consider the three non-linear functions F G and H in three variables x y and z The three
equations that are solved for the three variables are written as
F(x y z) = 0
G(x y z) = 0
H(x y z) = 0 [24]
The partial derivatives of the function F with respect to x y and z are given as
[25]
Similarly the partials derivatives can be expressed for the other two functions G and H
Newton-Raphson iterative method of solving the three equations in three variables
essentially deals with the solution of the incremental vector in the matrix equation given below
[26]
For the initial values of x y and z (say xi yi and zi) the right hand side vector contains the
values of the functions at the initial values (xi yi and zi) The 3times3 matrix on the left hand side
contains the partial derivatives of the functions with respect to the three variables at the initial
values Solutions of the matrix equation (Eq 26) result in the increments of the variables x y
and z The variables for the next iteration will then be xi + x yi + y and zi + z The
process of solving the matrix equation (Eq 26) is continued until the increments in the variables
x y and z is less than a very small quantity The iteration process is then said to be
29
converged and the values of the variables at convergence of the solution are the roots of the
system of the three fusion equations
The composition of LiNO3 NaNO3 and KNO3 and the eutectic temperature is solved by
using the Newton-Raphson iterative method Different from the data in previous literature the
eutectic temperature for the ternary is 116oC Besides the composition for each component is
also different from those published in literatures The new molten ternary system is composed of
2592 wt LiNO3 2001 wt NaNO3 and 5407 wt KNO3 The similar method is also applied
to other multi-component systems to determine the composition and eutectic temperature The
predicted melting points for new solar energy storage system are given Table41
Table 41 Calculated composition and melting point of multi-component molten salts systems
System Composition (wt) Calc Tmp
LiNO3 NaNO3 KNO3 NaNO2 KNO2 Mg(NO3)2 MgKN (degC)
Salt 1 259 20 541 - - - - 116
Salt 2 - 161 547 292 - - - 1238
Salt 3 175 142 505 178 - - - 986
Salt 4 115 104 274 - - - 507 986
Salt 5 172 139 476 172 41 - - 957
Salt 6 9 423 336 - 151 - - 1000
Salt 7 193 - 546 237 24 - - 1081
Salt 8 193 - 559 239 - 09 - 1008
Salt 9 154 172 324 - - 83 267 1036
30
CHAPTER 5
EXPERIMENTAL PROCEDURE
51 Melting point determination of molten salt mixtures
511 Materials
Ternary quaternary and quinary nirate and nitrite mixtures were tested in the thesis Most
components in the mixtures don‟t require any pre-preparation and can be used as received The
only exception is new developed MgKN which was composed of 6667 mol KNO3 and 3333
mol Mg(NO3)2 This unique compound is synthesized from magnesium nitrate hexahydrate
(98 Alfa Aesar) and potassium nitrate (ACS 990 min Alfa Aesar) and added into the
mixture as one single component As received magnesium nitrate hexahydrate is dehydrated
before synthesizing MgKN compound Weighted amount of magnesium nitrate taken in a
stainless steel crucible and placed on a hot plate in an argon atmosphere Temperature of the salt
is measured with a thermocouple immersed in the salt The temperature was held at 52315 K for
2 hours The salt solidifies to a white mass The temperature of the salt is then raised to 57315 K
slowly to remove any traces of moisture and to ensure complete dehydration The complete
removal of water is ascertained by weight loss
512 Apparatus and Procedure
31
Differential scanning calorimetry (DSC) analysis was performed using Perkin Elmer
Diamond DSC instrument and the setup is shown in fig 51 Heat flow and temperature can be
recorded in the instrument with an accuracy of 00001 mW and 001 K respectively The
measurements were made under purified nitrogen atmosphere with a flow rate of 20ccmin and at
a heating rate of 5 Kmin
Fig 51 Photography of set-up for DSC equipment
After dehydration if necessary each component was weighed to an accuracy of 01mg with
the electrical balance and mixed thoroughly in a stainless steel crucible Later the mixture is
heated up to certain temperature at which the entire salt melts At this temperature the salt
mixture was held for about 30 minutes The salt mixture is allowed to air cool to ambient
temperature This procedure is repeated 3 to 4 times to get the well-mixed compound Standard
aluminum pan with lid used for DSC measurements are weighed before the experiment Small
amount of the synthesized compound is placed carefully in the aluminum pan and closed with
the lid The lid is crimped by a sample press and the pan is weighed The weight of the sample is
32
determined by removing the weight of the pan and lid For the determination of melting point
and heat capacity (20-25) mg of the sample was used
Perkin-Elmer Diamond Differential Scanning Calorimeter (DSC) is used to measure the
melting point and heat capacity of compound The crimped ample pan was immediately put
inside the sample chamber of DSC after preparation and held at 52315 K for 10 hours to remove
the trace amount of moisture possibly caught in the process of loading sample and also to ensure
a homogeneous mixture In the experimental procedure a temperature range from 29815 K to
52315 K was set with a heating rate of 5 K min
1 followed by a cooling cycle at the same rate
This cycle is repeated for at least 6 times to ensure good mixture of the sample and
reproducibility of the results
52 Heat Capacity determination of molten salt mixtures
To start Cp measurement the same procedure as that of melting point determination is
followed with an addition of bdquoiso-scan-iso‟ steps to the program after 5-cycle temperature scan
Starting from 29815 K the temperature was held for 5 minutes before and after each scan step
Small temperature scan range is chosen to avoid thermal resistance between device and testing
sample except when the temperature is approaching the melting temperature The upper limit for
the Cp measurement was set to 62315 K in our experiments Since the change in the molar heat
capacity of the salt in the liquid state is very small the Cp data in the liquid state can be easily fit
to an equation and extrapolated to higher temperatures To get the value of molar heat capacity
of the sample heat flow curve for the baseline of the empty sample pan also needs to be obtained
immediately following the identical ldquoiso-scan-isordquo steps which were used for the actual sample
33
run The difference of heat flow between the actual crimpled sample and the empty sample pan is
the absolute heat absorbed by the test sample
53 Density determination of molten salt mixtures
Density measurement was carried out with standard densitometer which has fixed volume
Initial weight of the densitometer is measured and noted Salt composition of which the density
is measured is placed in a beaker on a hot place The densitometer is also placed on the same hot
plate The temperature is set to a fixed value above the melting point of the salt and is measured
by a thermocouple After the salt is melted and when the temperature shows stable reading the
molten salt is poured in to the densitometer up to the set mark on the sensitometer bottle The
weight of the densitometer with the molten salt is measured The weight difference between this
weight and the weight of empty densitometer gives the weight of the molten salt at the fixed set
temperature By knowing the fixed volume in the densitometer the density of the salt at that
temperature can be calculated This procedure is repeated at least three times to accurately
determine the density of the salt
34
CHAPTER 6
RESULT AND DISCUSSION
61 Melting point determination
611 DSC equipment calibration
Before the actual melting point measurement pure indium zinc metal and several
individual salts were used to calibrate the DSC equipment For metals only one sharp peak was
observed for each and the heat flow curve for indium metal is shown in fig 61 However larger
and boarder peaks are found for salts just like the condition illustrated in fig 62 for pure
potassium nitrate Based on the results shown in Table 61 the experimental data for melting
points and enthalpies of fusion have excellent agreement with the literature values [60-63] The
variation of point is within 07 and the variation of change of enthalpy is less than 3
Figure 61 Melting point calibration with indium sample
35
Figure 62 Melting point calibration with KNO3 sample
Table 61 Calibration data of melting points with different samples
Sample
Lit
Tmp
Expt
Tmp
Lit
Ttrans
Expt
Ttrans
Lit
ΔHfusion
Expt
ΔHfusion
Lit
ΔHtrans
Expt
ΔHtrans
degC degC degC degC Jg Jg Jg Jg
Indium 1566 1563 - - 286 278 - -
Zinc 4195 4188 - - 1086 1068 - -
LiNO3 2567 2550 - - 3617 3633 - -
NaNO3 3100 3081 2770 2753 1777 1756 147 152
KNO3 3370 3372 1330 1332 993 1005 538 529
612 Results
Differential scanning calorimetry (DSC) was used to determine the melting point and any
solid state phase transitions of the salt mixture A low scanning rate was chosen to record the
heat flow curve as function of temperature in order to improve the sensitivity of detection [64] It
helps to pick up any small endothermic peaks and also avoids the thermal resistance between the
36
internal furnace and sample Nine systems were chosen to test and the eutectic composition is
already listed in Table 41
All the selected systems are composed of alkaline nitrate and nitrite and most of them have
three basic components which are lithium sodium potassium nitrate or nitrite All the quaternary
and quinary systems were developed on the basis of the LiNO3-NaNO3-KNO3 baseline ternary
Figure 63-611 shows the DSC plot of all the salt systems DSC plots for each system were
collected for at least five runs (each run with fresh salt preparation) to ensure the reproducibility
All the onset temperatures peak temperatures predicted temperatures enthalpy of fusion for
melting peaks and the solid phase transformation temperatures are given in Table62
Figure 63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt
37
Figure 64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt
Figure 65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt
38
Figure 66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt
Figure 67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt
39
Figure 68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
Figure 69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
40
Figure 610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt
Figure 611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN salt
Table 62 illustrates that the predicted melting point is close to the experimental
determined value and most deviation is within 10 except for system 9 The great agreement
41
between experimental and calculated data verifies the accuracy and feasibility of the
thermodynamic modeling
Table 62 DSC results of melting point transition point and predicted melting point
System Tmp Ttrans ΔHfusion
Calculated degC Onset degC Peak degC Peak degC Jg
Salt 1 1160 994 1191 1043 600
Salt 2 1238 1150 1240 NA 97
Salt 3 986 940 999 NA 244
Salt 4 986 940 1010 NA 60
Salt 5 957 910 950 NA 62
Salt 6 1000 930 960 NA 86
Salt 7 1081 992 1003 793 60
Salt 8 1008 1010 1019 853 59
Salt 9 1036 834 892 NA 93
613 Discussion
It is observed that the first curve is different from last ones shown in the DSC plots and
this phenomenon is common for all the melting point measurement with DSC technique This
happened because in the first cycle the moisture caught by salt mixture especially the lithium
nitrate was removed in the process of heating Moreover the partially solidified sample in the
sample loading process can be re-homogenized in the first heating cycle [65-67] In figure 63
69 and 610 more than one endothermic peak was found The first smaller endothermic peak
refers to solid state phase transition of the salt mixture The second larger endothermic peak
refers to the melting of the salt Normally the onset temperature of transition is taken as the
experimental transition point for any metallic sample However in case of molten salts mixtures
since the thermal conductivity is low [68-74] the complete transition is ensured only at the peak
42
transition temperature The thermal gradient which exists due to the low thermal conductivity of
the salt results in internal heat flow which enhances the mixing in the salt Thus the transition
temperature is defined as the peak temperature of phase transition For salt No1 the small
endothermic peak happened before and was connected to the main peak which occurred at
39027K The first endothermic peaks for salt No 7 and 8 occurred at almost the same
temperature because of the similar composition for these two compounds Since the small
amount of magnesium nitrate and potassium nitrite contained in these two compounds the small
endothermic peak can hardly be related to these two components Obviously the rest three major
components must have something to do with the first peaks happened before the melting peaks
for both cases Each component among the major three ones were tested to find out any possible
solid phase transition peaks of them and the results shown in Table 63 which reveals that
lithium nitrate doesnt have any phase transition peak in solid state while potassium nitrate and
sodium nitrite both own the solid phase transformation peaks before their melting peaks
Table 63 Fusion and solid phase transition temperature for individual salts
System Tmp degC Ttrans degC ΔHfusion Jg ΔHtrans Jg
LiNO3 2550 - 3633 -
KNO3 3372 1332 1005 529
NaNO2 4311 4170 1119 880
The further investigation was carried out by running the KNO3-NaNO2 (550 wt and 238 wt )
binary compound with the very similar weight percentage as that in salt No 7 (546 wt and
237 wt) and salt No 8 (559wt and 239wt) By converting the weight percentage of the
studied binary system into 100 scale the weight fraction for sodium nitrate and potassium
nitrate can be rewritten as 698wt and 302wt The DSC plot for this binary system was
43
shown in fig 612 Although the solid transition and melting temperature were brought down by
adding lithium nitrate the shape of the plots in fig 69 and 610 are identical to that shown in fig
612 The enthalpy of solid state transformation of the binary salt was also converted to that in
both quaternary systems by using the weight fraction occupied by the binary system and the
comparable change of converted enthalpy between the binary system and two quaternary systems
indicates the relevance of the solid transition peaks in salt 7 and 8 to the combined effect of
potassium nitrate and sodium nitrite
Figure 612 DSC plot of 698wt KNO3- 302wt NaNO2 binary system
The similar analysis was applied to No1 salt to find out the reason for the presence of a
small peak adherent to the main melting peak before the melting point Sodium nitrate and
potassium nitrate binary system was synthesized based on the weight fraction of these two
constituent salts in No 1 salt DSC plot for the sodium nitrate-potassium nitrate binary system in
Fig 613 with the converted composition which is essentially same as that in the No1 ternary
system shows smooth heat flow curve before the melting peak which means the solid transition
peak in ternary is not simply relative to the binary system Assumption was made that the solid
44
phase transformation peak in the ternary salt is resulted from a multiple effect ie the
combination of one of the eutectic binary system involved in the ternary salt mixture and the
other binary system which is composed of the rest components The statement is verified that the
small peak in salt 1 is mainly caused by the solid phase transformation peak in lithium nitrate-
potassium nitrate eutectic binary system given the similar shape of the DSC plots in Fig 614
Since in salt No1 there is excess amount of sodium nitrate to form the lithium nitrate-sodium
nitrate binary system the rest sodium nitrate can interact with potassium nitrate and form new
sodium-potassium nitrate system which is shown in fig615 Besides a solid phase
transformation peak is observed in fig615 which has a very small area and won‟t change the
shape of phase transformation peak in fig614 when these two binary systems are combined and
form salt 1 The enthalpies of solid state transformation in two binary salts were also converted
to that in salt 1 by using the weight fractions occupied by both binary systems The difference
of the change of converted enthalpies between the lithium-potassium nitrate eutectic binary and
ternary system is filled by the binary mixture which is composed of the rest components sodium
nitrate-potassium nitrate The comparable converted values of enthalpy change between salt 1
and its two constituent binary systems further verify the assumption that the solid phase
transformation happened in salt 1 is mainly due to the combined effect of LiNO3-KNO3 eutectic
binary system and NaNO3-KNO3 binary system
45
Figure613 DSC plot of 270wt NaNO3-730wt KNO3 binary system
Figure614 DSC plot of 458wtLiNO3-542wtKNO3 binary system
46
Figure615 DSC plot of 460wt NaNO3-540wt KNO3 binary system
Unlike those discussed mixtures above salt No2 Salt No4 Salt No5 and Salt No6 have
only one relatively board melting peak and the heat flow curve before and after are very stable
Similarly there is no solid transformation peaks observed in salt No3 salt No7 and salt No8
However the heat flow after the melting peak in these cases are not stable and the main
endothermic peak is followed by a small hump which is considered to be the recrystallization
process once the compound entered into the liquid state When the process is finished the heat
flow curve returns to steady state
Heating rate is a significant parameter when collect the heat flow curves by using DSC
technique Fig 616(a) and Fig 616(b) illustrate the difference of melting point for salt No6 due
to the change of heating rate If the heating rate is 20oCmin the peak temperature and onset
temperature for the melting peak is 9669oC and 9221
oC respectively Once the heating rate is
decreased to 5oCmin these two temperatures will also be lowered to 9614
oC and 9190
oC The
difference is resulted from the diverse amount of thermal resistance between the testing sample
and the furnace inside the DSC instrument [75] Under higher heating rate the decisive thermal
47
resistance is raised due to the low thermal conductivity medium between the furnace and the
actual sample The insensitivity of gas heat conduction medium in DSC results each unit of
temperature increase on one side cannot have an immediate response on the other side of the gas
Consequently the sample holder which is connected the furnace has a higher temperature than
that inside the sample In this condition the value of temperature profile collected as the sample
holder temperature is larger than the actual temperature The deviation will be much smaller
when the heating rate is reduced In the case the thermal resistance will be decreased because of
the lower temperature gradient of the gas medium in the heating process As a result of that the
collected temperature from the sensor attached to the sample holder will be very close to the
actual temperature inside the testing sample
Figure 616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 20oCmin
heating rate
48
Figure 616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 5oCmin
heating rate
Besides the difference of temperature while using higher and lower heat rate the solution
of DSC will also be affected by different heating rate Fig 617(a) shows the DSC plot for salt
No 7 using the heating rate as 5oCmin and the DSC plot in Fig 617(b) is collected under the
heating rate as 20oCmin It can be observed that in the lower heating rate two small separated
peaks can be viewed as two parts of the solid phase transformation process while in Fig 617(b)
two small peaks before the melting peak merge and present as a board hump The qualification
of resolution can be executed by the term named resolution factor RMKE which is calculated as
the ratio of the peak heat flow value of the separated peaks to that of the concave point between
two peaks The equation for determining RMIKE is given in Eq 27 [76 77]
RMIKE =hpeakhmin [27]
49
Figure 617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 5oCmin
heating rate
Figure 617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 20oCmin
heating rate
In the case of lower heating rate the RMKE is determined to be 15 and the value for higher
heating rate is not available because the concave point of heat flow doesn‟t exist from
Fig617(b) Since the higher RMKE value indicates better resolution it can be stated that the
50
lower heating rate also results in greater sensitivity of the equipment to pick up any small
endothermic peaks
Besides the down-selected 9 compounds some more salt mixtures were also tested Most
of them were not selected to the final candidate for the thermal energy storage application
because of their higher melting point Table 64 gives some of the trial systems measured with
DSC technique It is illustrated that the melting points of mixtures with lower or even no content
of lithium nitrate turn out to be higher than those with sufficient amount of lithium nitrate For
most of the mixtures with melting point lower than 120oC the amount of lithium nitrate should
be larger than 81wt Also all of the systems in table 64 with lithium nitrate less than 15wt
have melting point higher than 140oC Based on the observation above it is concluded that the
lithium nitrate can be used as an additive to bring the melting point down for thermal energy
storage systems
51
Table 64 Melting points of candidate systems as function of temperatures
System Composition (wt)
Onset
Temp
Peak
Temp
(oC) (
oC)
LiNO3 ndash NaNO3 ndash KNO2 107 459 434 890 910
LiNO3 - KNO3 - NaNO2 196 564 241
1024 1046
LiNO3 - NaNO3 - KNO3 - KNO2 90 423 337 151
930 960
LiNO3 - NaNO3 - NaNO2 - KNO2 81 454 65 401
900 910
LiNO3 - KNO3 - NaNO2 - KNO2 193 546 237 24
992 1003
LiNO3 - KNO3 - NaNO2 ndash Mg(NO3)2 193 559 238 09
1010 1020
LiNO3 - NaNO3 - KNO3 - Mg(NO3)2
- MgK 154 172 324 83 267 834 892
LiNO3 - NaNO3 - KNO2 ndash Ca(NO3)2 14 390 333 263
1250 1470
NaNO3 - KNO3 - NaNO2 - KNO2 425 163 71 341
1407 1447
NaNO3 - KNO3 - KNO2 ndash Mg(NO3)2 432 146 380 42
1386 1421
NaNO3 - NaNO2 - KNO2 - Ca(NO3)2 451 92 410 48
1150 1390
LiNO3 - NaNO3 - NaNO2 - KNO2 -
Ca(NO3)2 15 393 37 323 232 1380 1480
LiNO3 - NaNO3 - KNO2 - Ca(NO3)2 -
Mg(NO3)2 14 379 313 275 20 1339 1534
62 Heat capacity determination
621 Heat capacity calibration
DSC was also calibrated for the heat capacity measurement Lithium nitrate sodium
nitrate and potassium nitrate were examined for the heat capacities from room temperature to
upper limit temperature for the instrument In liquid state the heat capacity values for each salt
can be fit to straight line with trace amount of increasing trend Since the temperature range from
the onset temperature of liquid state to the upper limit of DSC is relatively small the heat
capacity values for pure individual salts can be viewed as constants The comparison between the
theoretical and experimental heat capacity data is given in Table 65 Except lithium nitrate the
52
experimental heat capacities data for the rest two systems are almost same as the literature Even
for lithium nitrate which demonstrates the biggest difference from the literature data the 28
vibration is still within a reasonable range
Table 65 Calibration data of heat capacities with different samples
Sample Lit Cp Expt Cp
JgK JgK
LiNO3 218 212
NaNO3 169 167
KNO3 140 139
622 Results
The materials used in the heat capacity measurements are the same as those in the melting
point experiments Molar heat capacities of the all compound were measured by the DSC
equipment from room temperature to 62315 K The heat flow is recorded as a function of
temperature in ldquoiso-scan-isordquo steps at intervals of 20 K The bdquoiso stage‟ refers to isothermal
holding at a particular temperature bdquoscan stage‟ refers to the heat flow recording at a heating rate
of 5 K min1
up to a an increment of 25 K followed by another isothermal holding stage This is
a standard procedure followed in the measurement of heat capacity of materials using the DSC
equipment [63 64] This procedure of heat capacity measurement has two advantages (i) any
heat fluctuations during the recording are avoided by the isothermal steps and (ii) any phase
transition can be highlighted by the choice of temperature range The absolute heat flow to the
sample is determined by subtracting the heat flow collected by running a baseline curve with an
empty pan Because the heat capacity measurement in the heating process corresponds to
53
collecting the value of required heat flow at each temperature all the heat capacity plots have the
same shape with that of heat flow in the melting point measurements Take the heat capacity plot
of LiNO3-NaNO3-KNO3 ternary system as an instance which is shown in fig 618 the heat
capacity curve also has two different peaks The first little peaks corresponds to one occurs at
39027K which was observed in fig 63 the second large and sharp peak happened right after the
small one is prevalent to the endothermic peak with the peak temperature as 39027 K Similarly
after the phase transformation the heat capacity in liquid state becomes very stable and increase
with temperature linearly with little slope
Fig 618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system as function of
temperature
The heat capacity change as function of temperature for salt No1 was illustrated in fig
619 Based on the trend of heat capacity in the liquid state any value for the system in the liquid
can be extrapolated The expressions for heat capacity in liquid state for the new molten salt
systems were discussed and given in the next sectionTable66 shows the specific heat capacity
54
of the all the selective compounds measured at 62315 K and extrapolated at 77315K Besides
the molar heat capacities at 77315K are given in Table 66 of all the salts
Fig 619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K
Table 66 Heat capacity of selected new TES molten salt mixtures
System Expt (62315K) Extrapolated(77315K) Extrapolated(77315K)
Cp JgK Cp JgK Molar Cp JmolK
Salt 1 153 170 1521
Salt 2 143 168 1515
Salt 3 148 155 2183
Salt 4 153 166 1411
Salt 5 153 170 1440
Salt 6 151 163 1435
Salt 7 156 167 1443
Salt 8 155 168 1410
Salt 9 161 170 1937
55
623 Thermodynamic properties
The standard thermodynamic properties such as entropy enthalpy and Gibbs energy for
salt mixtures are determined from the experimental data of melting point and heat capacity in the
temperature range of the present study and expression for determining these properties are given
in equation 28-30 In thermodynamics all these three properties are related to heat capacity and
its variances with temperature In the studied temperature range (29815K-62315K) they can be
described as expression includes heat capacity
[28]
[29]
[30]
Where Tt is the solid transformation temperature Tmp is the melting point ΔHt is enthalpy of
solid phase transformation and ΔHfusion is enthalpy of fusion The standard thermodynamic
properties entropy enthalpy and Gibbs energies as function of temperature for each compound
are expressed in the following section
6231 LiNO3-NaNO3-KNO3 (Salt 1)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3
compound (i) solid state 1 (32315-38415) K (ii) liquid state (40315-62315) K Accordingly
56
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62311 Heat capacity of solid state 1 (29815-38415) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the solid state 1 in the
temperature range of 29815 to 38415 K is fit to a second order polynomial equation Eqn (31)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[31]
( ) K
R2 = 0982
62312 Heat capacity of liquid state (40315-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a linear equation Eqn (32) gives the linear
equation along with the least square fit parameter (R2) in the temperature range for the liquid
state of the compound
JKmol [32]
57
R2 = 0947
Heat capacity data of the LiNO3-NaNO3-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62313 Thermodynamic properties of solid state 1(29815-38415) K
JKmol [33]
Jmol [34]
[35]
Jmol
62314 Thermodynamic properties of liquid state 2(40315-62315) K
[36]
58
JKmol
Jmol [37]
[38]
Jmol
Among the equations above equation (33)-(35) refer to the thermodynamic properties for
solid state equations (36)-(38) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature ranges for solid and liquid state are
given in Table A1 and A2 in appendix A respectively with the corresponding heat capacity as
function of temperature
6232 NaNO3-NaNO2-KNO3 (Salt 2)
The heat capacity data can be divided into two sections for NaNO3-NaNO2-KNO3
compound (i) solid state 1 (32315-39215) K (ii) liquid state (41315-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62321 Heat capacity of solid state 1 (29815-39215) K
59
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the solid state in the
temperature range of 29815 to 39215 K is fit to a second order polynomial equation Eqn (39)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[39]
( ) K
R2 = 0978
62322 Heat capacity of liquid state (40315-62315) K
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a second order polynomial equation Eqn (40)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[40]
R2 = 0941
60
Heat capacity data of the NaNO3-NaNO2-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62323 Thermodynamic properties of solid state 1(29815-39215) K
JKmol [41]
Jmol [42]
[43]
Jmol
62324 Thermodynamic properties of liquid state 2(40315-62315) K
JKmol [44]
61
Jmol [45]
[46]
Jmol
Among the equations above equation (41)-(43) refer to the thermodynamic properties for
solid state equations (44)-(46) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table B1 and B2 in appendix B respectively with the corresponding heat capacity as
function of temperature
6233 LiNO3-NaNO3 -KNO3-MgK (Salt 3)
The heat capacity data can be divided into two sections for LiNO3-NaNO3 -KNO3-MgK
compound (i) solid state 1 (29815-36415) K (ii) liquid state (42115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62331 Heat capacity of solid state 1 (29815-36415) K
62
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the solid state in the
temperature range of 29815 to 36415 K is fit to a second order polynomial equation Eqn (47)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[47]
( ) K
R2 = 0995
62332 Heat capacity of liquid state (42115-62315) K
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the liquid state in the
temperature range of 42115 to 62315 K is fit to a second order polynomial equation Eqn (48)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[48]
R2 = 0963
63
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
62333 Thermodynamic properties of solid state 1(29815-36415) K
JKmol [49]
Jmol [50]
[51]
Jmol
62334 Thermodynamic properties of liquid state 2(42115-62315) K
64
JKmol [52]
Jmol [53]
[54] [29]
Jmol
Among the equations above equation (49)-(51) refer to the thermodynamic properties for
solid state equations (52)-(54) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table C1and C2 in appendix C respectively with the corresponding heat capacity as
function of temperature
6234 LiNO3-NaNO3-KNO3-NaNO2 (Salt 4)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-NaNO2
compound (i) solid state 1 (29815-36315) K (ii) liquid state (38115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62341 Heat capacity of solid state 1 (29815-36315) K
65
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the solid state in the
temperature range of 29815 to 36315 K is fit to a second order polynomial equation Eqn (55)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[55]
( ) K
R2 = 0995
62342 Heat capacity of liquid state (38115-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the liquid state in the
temperature range of 38115 to 62315 K is fit to a second order polynomial equation Eqn (56)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[56]
R2 = 0972
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
66
62343 Thermodynamic properties of solid state 1(29815-36315) K
JKmol [57]
Jmol [58]
[59]
Jmol
62344 Thermodynamic properties of liquid state 2(38115-62315) K
JKmol [60]
Jmol [61]
67
[37]
Jmol [62]
Among the equations above equation (57)-(59) refer to the thermodynamic properties for
solid state equations (60)-(62) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table D1 and D2 in appendix D respectively with the corresponding heat capacity as
function of temperature
6235 LiNO3-NaNO3-NaNO2-KNO3-KNO2 (Salt 5)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-NaNO2-KNO3-
KNO2 compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62351 Heat capacity of solid state 1 (29815-35915) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
in the temperature range of 29815 to 35915 K is fit to a second order polynomial equation Eqn
(63) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
68
[63]
( ) K
R2 = 0996
62352 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the liquid
state in the temperature range of 37515 to 62315 K is fit to a second order polynomial equation
Eqn (64) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[64]
R2 = 0969
Heat capacity data of the LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62353 Thermodynamic properties of Solid state 1(29815-35915) K
JKmol [65]
69
Jmol [66]
[67]
Jmol
62354 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [68]
Jmol [69]
[45]
Jmol [70]
70
Among the equations above equation (65)-(67) refer to the thermodynamic properties for
solid state equations (68)-(70) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table E1 and E2 in appendix E respectively with the corresponding heat capacity as
function of temperature
6236 LiNO3-NaNO3-KNO3-KNO2 (Salt 6)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-KNO2
compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62361 Heat capacity of solid state 1 (29815-36515) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the solid state in the
temperature range of 29815 to 36515 K is fit to a second order polynomial equation Eqn (71)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[71]
( ) K
R2 = 0998
71
62362 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the liquid state in the
temperature range of 37515 to 62315 K is given in Table 20 The data is fit to a second order
polynomial equation Eqn (72) gives the linear equation along with the least square fit parameter
(R2) in the temperature range for the liquid state of the compound
[72]
R2 = 0953
Heat capacity data of the LiNO3-NaNO3-KNO3-KNO2 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62363 Thermodynamic properties of solid state 1(29815-35915) K
JKmol [73]
Jmol [74]
72
[75]
Jmol
62364 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [76]
Jmol [77]
Jmol [78]
Among the equations above equation (73)-(75) refer to the thermodynamic properties for
solid state equations (76)-(78) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
73
given in Table F1 and F2 in appendix F respectively with the corresponding heat capacity as
function of temperature
6237 LiNO3-KNO3-NaNO2-KNO2 (Salt 7)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62371 Heat capacity of solid state 1 (29815-35415) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 1 in
the temperature range of 29815 to 35415 K is fit to a second order polynomial equation Eqn
(79) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[79]
(29815-35415) K
R2 = 0993
62372 Heat capacity of solid state 2 (36215-37315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 2 in
the temperature range of 36215 to 37315 K is fit to a second order polynomial equation Eqn
74
(80) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 2 of the compound
[80]
R2 = 0977
62373 Heat capacity of liquid state (37915-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the liquid state in the
temperature range of 37915 to 62315 K is fit to a linear equation Eqn (81) gives the
polynomial equation along with the least square fit parameter (R2) in the temperature range for
the liquid state of the compound
[81]
R2 = 0961
Heat capacity data of the LiNO3-KNO3-NaNO2-KNO2 compound in the two solid states
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62374 Thermodynamic properties of solid state 1(29815-35415) K
75
JKmol [82]
Jmol [83]
[84]
Jmol
62375 Thermodynamic properties of solid state 2(36215-37315) K
JKmol [85]
Jmol [86]
76
[87] [62]
Jmol
62376 Thermodynamic properties of liquid state (37915-62315) K
JKmol [88]
Jmol [89]
Jmol [90]
Among the equations above equation (82)-(84) refer to the thermodynamic properties for
solid 1 equation (85)-(87) refer to the thermodynamic properties for solid 2 equations (88)-(90)
refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy values
77
in the studied temperature range for solid 1 solid 2 and liquid state are given in Table G1-G3 in
appendix G respectively with the corresponding heat capacity as function of temperature
6238 LiNO3-KNO3-NaNO2-Mg(NO3)2 (salt 8)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62381 Heat capacity of solid state 1 (29815-33715) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid
state 1 in the temperature range of 29815 to 33715 K is fit to a second order polynomial
equation Eqn (91) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the solid state 1 of the compound
[91]
(29815-33715) K
R2 = 0994
62382 Heat capacity of solid state 2 (36115-36415) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid state 2
in the temperature range of 36115 to 36415 K is given in Table 4 The data is fit to a second
78
order polynomial equation Eqn (92) gives the polynomial equation along with the least square
fit parameter (R2) in the temperature range for the solid state 2 of the compound
[92]
R2 = 0992
62383 Heat capacity of liquid state (41115-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the liquid state in
the temperature range of 41115 to 62315 K is given in Table 5 The data is fit to a linear
equation Eqn (93) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the liquid state of the compound
[93]
R2 = 0934
Heat capacity data of the LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the two solid
states follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62384 Solid state 1(29815-35415) K
79
JKmol [94]
Jmol [95]
[96]
Jmol
62385 Solid state 2(36115-36415) K
JKmol [97]
80
Jmol [98]
[99] [74]
Jmol
62386 Liquid state (41115-62315) K
JKmol [100]
Jmol [101]
Jmol [102]
Among the equations above equation (94)-(96) refer to the thermodynamic properties for
solid 1 equation (97)-(99) refer to the thermodynamic properties for solid 2 equations (100)-
(102) refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy
81
values in the studied temperature range for solid 1 solid 2 and liquid state are given in Table H1
and H2 in appendix H respectively with the corresponding heat capacity as function of
temperature
6239 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK(Salt 9)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-
Mg(NO3)2-MgK compound (i) solid state 1 (29815-35315) K (ii) liquid state (39115-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62391 Heat capacity of solid state 1 (29815-35315) K
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state in the temperature range of 29815 to 35315 K is fit to a second order polynomial equation
Eqn (103) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[103]
( ) K
R2 = 0996
62392 Heat capacity of liquid state (39115-62315) K
82
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the liquid
state in the temperature range of 39115 to 62315 K is fit to a second order polynomial equation
Eqn (104) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[104]
R2 = 0951
Heat capacity data of the LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62393 Solid state 1(29815-35315) K
JKmol [105]
Jmol [106]
83
[107]
Jmol
62394 Liquid state 2(39115-62315) K
JKmol [108]
Jmol [109]
[110]
Jmol
Among the equations above equation (105)-(107) refer to the thermodynamic properties
for solid state equations (108)-(110) refer to thermodynamic properties of the liquid The
entropy enthalpy and Gibbs energy values in the studied temperature range for solid and liquid
state are given in Table I1 and I2 in appendix I respectively with the corresponding heat
capacity as function of temperature
84
624 Discussion of Gibbs energy change for molten salts
The Gibbs energy change data as function of temperature for 9 systems are given in fig
620 and the values at 62315K are shown in Table 67 Every system demonstrates continuous
curve throughout the whole studied temperature range Most of systems have similar Gibbs
energy change values for each temperature spot due to the comparable compositions and
properties of constituent salts However salt 3 and salt 9 Both of these salts have certain
amount of MgKN compound which presents large absolute amount of change of Gibbs energy in
the same studied temperature range [66] Since the change of Gibbs energy for multi-component
mixture is relevant to that of each constituent salt the large absolute value of ΔG of MgKN
mainly contributes to the largely negative value of salt 3 and salt 9 shown in fig 620 Besides
it is observed that most systems contain nitrite salts present lower absolute value of Gibbs energy
change For example salt 1 doesn‟t include any nitrite salt and has a relatively high absolute
value of Gibbs energy change as 1704kJmol while other systems having nitrite salts show lower
value varies from 1372kJmol to 1592kJmol
85
Fig 620 Change of Gibbs energy as function of temperature for molten salt systems
Table 67 Change of Gibbs energy values at 62315K for molten salt systems
SNo System ΔG(kJmol)
1 LiNO3-NaNO3-KNO3 1704
2 NaNO3- NaNO2- KNO3 1372
3 LiNO3- NaNO3- KNO3- MgKN 2807
4 LiNO3- NaNO3- KNO3- NaNO2 1443
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1441
6 LiNO3-NaNO3-KNO3-KNO2 1570
7 LiNO3-KNO3-NaNO2-KNO2 1592
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1583
9 LiNO3-NaNO3-KNO3-Mg(NO3)2 -MgKN 2217
86
63 Density determination
631 Density calibration
Several pure molten salts are used to calibrate the density measurement set-up before the
actual density measurement All the density values decrease as function of temperature in the
liquid state and follow the same linear equations as described in eq 4 The experimental values
at 350oC for KNO3 NaNO3 and LiNO3 are selected to compare with the literature data at the
same temperature The results are shown in Table 68 Based on the comparison of the literature
data and the experimental data the variation of density for molten nitrate salt is within in 4
Table 68 Calibration of density measurements with different pure nitrate salts
Sample Literature density Experimental density
gcm3 gcm
3
LiNO3 1727 1701
NaNO3 2066 2144
KNO3 1860 1855
632 Results and discussions
The density result of the salt as function of temperature is plotted for all the salts in Figure
621 and Figure 622 It is observed that the temperature dependence of density above the
melting point is different from that in solid state As known in solid state the density of salt has
an exponential relation with temperature while in these liquid cases the density values have
linearly dependence with temperature The stable variation as function of temperature allows the
extrapolation of density at even higher temperature The regression analysis is performed to get
the coefficient used for describing eq 4 and the results for the coefficients are shown in
87
Table69 [78-80] It is observed that the change of composition is implied on the coefficient A
which indicates the initial point at 150oC The temperature dependence coefficient B doesn‟t
change much with composition which may be mainly affected by the group of anion and cation
Table 69 Coefficient A and B for density determination of salt 1-salt 9
Salt No System A Btimes10
3
(gcm3) (gcm
3degC)
1 LiNO3-NaNO3-KNO3 2032 0493
2 NaNO3- NaNO2- KNO3 2081 0570
3 LiNO3- NaNO3- KNO3-MgKN 2055 0526
4 LiNO3- NaNO3- KNO3- NaNO2 2033 0520
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 2018 0485
6 LiNO3-NaNO3-KNO3-KNO2 2060 0554
7 LiNO3-KNO3-NaNO2-KNO2 2048 0554
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 2044 0524
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 2060 0566
Figure 621 The densities of the salt 1-salt 5 as function of temperature
88
In figure 621 all the density values are clustered around 198gcm3 at 150
oC to
186gcm3 at high temperature end and the deviation of density between all the mixtures is within
in 0047g cm3 Among all the salt mixtures the NaNO3-NaNO2-KNO3 ternary system
demonstrates the highest density value throughout the studied temperature range and LiNO3-
NaNO3-KNO3 ternary system LiNO3- NaNO3-KNO3-NaNO2 quaternary system and LiNO3-
NaNO3-KNO3-NaNO2-KNO2 quinary system show densities at the bottom side of Fig 621 For
salt 2 which doesn‟t contain any lithium nitrate the density at every selected temperature spot
is obviously higher than that of salt 1 4 and 5 which have large amount of lithium nitrate
Moreover the salt 3 which contains the relatively small amount of lithium nitrate stays in
between of salt 1 and salt 2 This comparison illustrates that the addition of lithium nitrate has
an offsetting effect on density for molten salt and it is consistent with previous literature reports
[81] The four systems presented in figure 622 also show even closer density values in the
studied temperature range Similarly salt 6 which contains the least lithium nitrate has the
largest density Salt 7 and salt 8 have almost same composition for the three dominating
components as a result of that the density curves for both mixtures are determined by the same
regression coefficient A and B Moreover the larger amount of lithium nitrate involved in these
two salt mixtures contributes to the lower density given in figure622 which further verifies the
significantly offsetting effect of lithium nitrate on density
89
Figure 622 The densities of the salt 6-salt 9 as function of temperature
The salt mixtures with maximum and minimum amount of lithium nitrate were plotted and
compared with equimolar NaNO3-KNO3 binary system and pure KNO3 salt in Fig623 [82 83]
It is observed that the NaNO3-KNO3 binary system has very similar density value to that of salt
2 because of the analogous type and composition of component in both salts The density of
pure KNO3 is slightly lower than the binary salt mixture which indicates the density of NaNO3 is
close to but higher than KNO3 in the studied temperature range Salt 1 shows the lowest density
in Fig623 due to the offsetting effect on density caused by lithium nitrate which has been
discussed above
90
Figure 623 Density of the salt 1 salt 2 as function of temperature compared to the
equimolar NaNO3-KNO3 binary system and pure KNO3
64 Thermal energy storage density of molten salts
The energy density which is considered as one of the most significant parameters of TES
application can be evaluated by calculation based on the measured density heat capacity and
working temperature range The equation of the thermal energy storage density (E) at working
temperature of 500oC is expressed in equation 111
E = Cp (500-Tm) [111]
Where Cp and are extrapolated heat capacity and density at 500oC respectively Tm is
melting point for salt mixture The extrapolation of density and heat capacity is based on the
linear temperature dependence for both parameters in molten state and the values are shown in
Table 610
91
Table 610 Extrapolated value of density and heat capacity at 500oC of salt 1-salt 9
Salt
No System
Density Heat Capacity
(gmL) (JgK)
1 LiNO3-NaNO3-KNO3 1785 170
2 NaNO3- NaNO2- KNO3 1796 168
3 LiNO3-NaNO3-KNO3-MgK 1773 155
4 LiNO3- NaNO3- KNO3- NaNO2 1792 166
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1796 170
6 LiNO3-NaNO3-KNO3-KNO2 1783 163
7 LiNO3-KNO3-NaNO2-KNO2 1771 167
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1782 168
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 1777 170
The calculated energy density for each salt is given in Table 611 compared with that of
solar salt (NaNO3-KNO3) All the new synthesized salt mixtures have significantly higher energy
density than solar salt and salt 3 shows the highest energy density among the new salts
Although salt 1 has higher heat capacity and good melting point the energy density is still the
lowest among new salt mixtures given by the effect of low density The conclusion can be drawn
from these observations that the energy density is a property affected by multiple parameters and
every part plays an important role in determining the efficiency of energy storage of salt
mixtures
92
Table 611 Energy density of salt 1-salt 9 compare to solar salt
The gravimetric storage density of new molten salts are listed in Table 612 and compared
with those different storage systems in fig 624 It is found that in the parabolic trough working
temperature range the gravimetric storage densities of new molten salts are located on the higher
side Even though some reported sensible energy storage liquids have larger gravimetric density
values than the new salts the maximum working temperatures reveal the instable working
condition at 500oC Taking conversion efficiency thermal stability and gravimetric storage
density into considerations the new molten salts are the most suitable choices of the sensible
heat storage for parabolic trough application
Salt No System Energy Density
500degC (MJm3)
0 NaNO3- KNO3 756
1 LiNO3-NaNO3-KNO3 1162
2 NaNO3- NaNO2- KNO3 1135
3 LiNO3-NaNO
3-KNO
3-MgKN 1099
4 LiNO3- NaNO
3- KNO
3- NaNO
2 1189
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1232
6 LiNO3-NaNO3-KNO3-KNO2 1174
7 LiNO3-KNO3-NaNO2-KNO2 1183
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1192
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 1242
93
Fig 624 Gravimetric storage density comparison of different energy storage systems as
function of temperature
Table 612 Gravimetric storage densities for solar salt and new molten salts
Salt
No System
Gravimetric Storage Density
500degC (kJkg)
0 NaNO3- KNO3 404
1 LiNO3-NaNO3-KNO3 560
2 NaNO3- NaNO2- KNO3 533
3 LiNO3-NaNO
3-KNO
3-MgKN 575
4 LiNO3- NaNO
3- KNO
3- NaNO
2 612
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 595
6 LiNO3-NaNO3-KNO3-KNO2 594
7 LiNO3-KNO3-NaNO2-KNO2 604
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 610
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 649
94
CHAPTER 7
CONCLUSION
The melting points of new molten salts were experimentally determined using DSC
Different from metals the melting point was chosen as the peak temperature rather than onset
temperature of the endothermic peak due to the low thermal conductivity and broad phase
transition range of the molten nitride salt mixture All of the nine new molten salts have melting
points from 89oC to 124
oC which are much lower than current sodium-potassium binary solar
salt Some systems such as salt No1 No7 and No8 have solid phase transformation observed
from the DSC plots It is found that the phase transformations of salt No 7 and No 8 are mainly
contributed to the KNO3-NaNO2 binary system while the small solid transformation peak of salt
No1 is resulted from the combined effect of the KNO3-LiNO3 eutectic binary system involved in
the ternary salt and another binary system which is composed of the rest components The
heating rate of DSC was revealed as a significant parameter for the any endothermic peak
determination When using lower heating rate the thermal resistance between the studied sample
and the furnace will be minimal and the resolution of peak detection will be enhanced
The heat capacities of all the multi-component salts (1 to 9) were determined using DSC
and found varying from 143 to 161 JgK at 350oC The heat capacity in the liquid state
demonstrates linear increase trend as function of temperature On the basis of that the heat
capacity was extrapolated to parabolic trough operating temperature of 500oC Besides heat
capacity data as function of temperature are fit to polynomial equation and thermodynamic
95
properties like enthalpy entropy and Gibbs energies of the compound as function of temperature
are subsequently deduced
Experimental measurements of density of multi-component systems were conducted as
function of temperature in their liquid state In liquid state the density values decrease linearly
as temperature increases The results of those mixtures were compared to the solar salt and
individual constituent salts The comparison demonstrates that the addition of lithium nitrate
lowers the density which is consistent with the observation that lithium nitrate has the lowest
density among all the individual salts in the studied temperature range On the basis of densities
heat capacities and the melting points energy storage density for all the new salts were
calculated and compared to the binary solar salt Among all the new molten salt systems
LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN quinary system (salt 9) presents the largest thermal
energy storage density as well as the gravimetric density values Moreover the larger thermal
energy storage as well as gravimetric storage densities compared to the solar salt indicate the
better energy storage capacities of new salts for solar power generation systems
96
REFERENCES
[1] JF Manwell JG McGowan and AL Rogers Wind Energy Explained-Theory Design and
Application second edition John Wiley and sons Ltd UK 2009
[2] MJ Pasqualetti Morality space and the power of wind-energy landscapes Geographical
Review 90 2000 381-394
[3] DG Fink and HW Beaty Standard Handbook for Electrical Engineers Eleventh Edition
McGraw-Hill New York 1978
[4] R Bertani Geothermal Energy An Overview on Resources and Potential Proceedings of the
International Conference on National Development of Geothermal Energy Use 2009 Slovakia
[5] TA Volk LP Abrahamson EH White E Neuhauser E Gray C Demeter C Lindsey J
Jarnefeld DJ Aneshansley R Pellerin and S Edick Developing a Willow Biomass Crop
Enterprise for Bioenergy and Bioproducts in the United States Proceedings of Bioenergy
2000 October 15-19 2000 Buffalo New York USA
[6] M Asplund N Grevesse and AJ Sauval The new solar abundances-Part I the
observations Communications in Asteroseismology 147 2006 76-79
[7] DRWilliams Sun Fact Sheet NASA 2004
httpnssdcgsfcnasagovplanetaryfactsheetsunfacthtml
[8] U Herrmann Survey of Thermal Energy Storage for Parabolic Trough Power Plants Journal
of Solar Energy Engineering 124 2002 145-152
[9] Rocket Research Company Chemical energy storage for solar thermal conversion SAND79-
8198 Livermore Sandia National Laboratories 1979
97
[10] A Steinfeld and R Palumbo Solar thermochemical process technology Encyclopedia of
Physical Science and Technology 2001 237-256
[11] EA Fletcher Solar thermal processing a review Journal of Solar Energy Engineering
2001 63-74
[12] R W Bradshaw and Nathan P Siegel Molten Nitrate Salt Development for Thermal
Energy Storage in Parabolic Trough Solar Power Systems of the Energy Sustainability 2008
Conference August 10-14 2008 Jacksonville Florida USA
[13] B Kelly H Price D Brosseau and D Kearney Adopting NitrateNitrite Salt Mixtures as
the Heat Transport Fluid in Parabolic Trough Power Plants Proceedings of the Energy
Sustainability 2007 Conference June 27-30 2007 Long Beach CA
[14] H Reilly and G Kolb Evaluation of Molten Salt Power Tower Technology Based on
Experience at Solar Two SAND2001-3674 Sandia National Laboratories 2001
[15] T Wendelin ldquoParabolic Trough VSHOT Optical Characterization in 2005-2006rdquo NREL
wwwnrelgovdocsfy06osti40024pdf
[16] RB Diver C Andraka S Rawlinson V Goldberg and G Thomas The Advanced Dish
Development System Project ASME Proceedings of Solar Forum 2001 Washington DC
[17] S D Odeh G L Morrison and M Behnia Modelling of parabolic trough direct steam
generation solar collectors Solar Energy 62 1998 396-406
[18] V Heinzel H Kungle and M Simon Simulation of a parabolic trough collector ISES
Solar World Congress Harare Zimbabwe 1-10
[19] S D Odeh G L Morrison and M Behnia Modeling of Parabolic Trough Direct
Generation Solar Collectors Solar Energy 62 1998 395-406
[20] Ezzat Optimum Working Fluids for Solar Powered Rankine Cycle Cooling of Buildings
Solar energy 25 1980 235-241
98
[21] R G Reddy Ionic Liquids How well do we know them editorial Journal of Phase
Equilibria and Diffusion 27 2006 210-211
[22] M Zhang and R G Reddy Application of [C4min][Tf2N] Ionic Liquid as Thermal
Storage and Heat Transfer Fluids editor J Weidner ECS Transactions 2 (28) 2007 27-32
[23] M Zhang and R G Reddy Evaluation of Ionic Liquids as Heat Transfer Materials in
Thermal Storage Systems Energy Energy Materials editors F Dogan M Awano D Singh
and B Tuttle ASM International Materials Park Ohio USA MSampT‟07 2007 151-160
[24] R G Reddy Novel Applications of Ionic Liquids in Materials Processing Advanced
Structural and Functional Materials Design 2008 Journal of Physics Conference Series (JPCS)
165 2009 1-6
[25] RW Bradshaw and DE Meeker High-temperature stability of ternary nitrate molten
salts for solar thermal energy systems Solar Energy Materials 21 1990 51-60
[26] AS Trunin Designing and investigations of salt systems for solar energy utilization
Utilization of sun and other radiation sources in materials research Kiev Naukova Dumka 1983
p 228-38
[27] D J Rogers and G J Janz Melting-crystallization and premelting properties of sodium
nitrate-potassium nitrate Enthalpies and heat capacities Journal of Chemical and Engineering
Data 27 1982 424-428
[28] D Kearney U Herrmann P Nava and B Kelly Assessment of a molten salt heat transfer
fluid in a parabolic trough solar field Journal of Solar Energy Engineering 125 2003 170-176
[29] Q Peng J Ding X Wei J Yang and X Yang The preparation and properties of multi-
component molten salts Applied Energy 87 2010 2812-2817
[30] E M Levin C R Robbins and H F McMordie Phase Diagrams for Ceramists American
Ceramic Society 1964
[31] J C Oxley J L Smith E Rogers and M Yu Ammonium nitrate thermal stability and
explosivity modifiers Thermochimica Acta 384 2002 23-45
99
[32] LG Marianowski and HC Maru Latent heat thermal energy storage systems above
4508oC Proceedings of 12th intersociety energy conversion engineering conference 1977 55-
66
[33] HC Maru JF Dullea A Kardas L Paul LG Marianowski E Ong et al Molten salts
energy storage systems Chicago Final Report of the Institute of Gas Technology 1978
[34] WM Philips and JW Stears Advanced latent heat of fusion thermal energy storage for
solar power stations Proceedings of 20th intersociety energy conversion engineering conference
2 1985 384-391
[35] KE Mayo Heat source systems USA Patent 3605720 1971
[36] JI Eichelberger and HD Gillman Investigation of metal fluoride thermal energy storage
material Proceedings of 12th intersociety energy conversion engineering conference 1977 567-
574
[37] GR Heidenreich and MB Parekh Thermal energy storage for organic Rankine cycle solar
dynamic space power systems Proceedings of 21st intersociety energy conversion engineering
conference 2 1986 791-797
[38] IK Garkushin AC Trunin TT Miftakhov and MA Dibirov Salt heat storage
composition USSR Patent 1036734 1983
[39] W M Philips and J W Stears Advanced latent heat of fusion thermal energy storage for
solar power stations In Proceedings of 20th intersociety energy conversion engineering
conference 2 1985 384-391
[40] Y Takahashi M Kamimoto Y Abe R Sakamoto K Kanari and T Ozawa Investigation
of latent heat-thermal energy storage materials IV Thermoanalitical evaluation of binary eutectic
mixtures of NaOH with LiOH or KOH Thermochim Acta 121 1987 193-202
[41] C E Birchenall and A F Riechman Heat storage in eutectic alloys Metall Trans A
11A(8) 1980 1415-1420
100
[42] Y Takahashi R Sakamoto and M Kamimoto Heat capacities and latent heats of LiNO3
NaNO3 and KNO3 International Journal of Thermophysics 9(6) 1988 1081-1090
[43] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate Mixtures
Journal of Chemical Engineering Data 8(3) 1963 469
[44] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical Engineering Data 6 (4) 1961 493
[45] GF Petersen WA Ewing and G P Smith Densities of Some Salt Mixtures Journal of
Chemical Engineering Data 6 (4) 1961 540
[46] G J Janz and M R Lorenz Precise Measurement of Density and Surface Tension at
Temperatures up to 1000degC in One Apparatus Review of Scientific Instruments 31 (1) 1960
18-23
[47] G J Janz C B Allen N P Bansal R M Murphy and R P Tomkins Physical Properties
Data Compilations Relevant to Energy Storage II Molten Salts Data on Single and Multi-
Component Salt Systems National Bureau of Standards NSRDS-NBS 61 Part II April 1979
[48] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation Equations
for Critically Evaluated Density Surface Tension Electrical Conductance and Viscosity Data
Journal of Physical and Chemical Reference Data 17 1988 2
[49] A T Ward and G J Janz Molten Carbonate Electrolytes Electiral Conductance Density
and Surface Tension of Binary and Ternary Eleclrochimica Acta 10 1965 849-857
[50] Y Takahashi R Sakamoto and MKamimoto Heat Capacities and Latent Heat of LiNO3
NaNO3 amp KNO3 International Journal of Thermophysics 9 1998 1081-1090
[51] R W Carling Heat capacities of NaNO3 and KNO3 up to 800 K Thermochimica Acta 60
1983 265-275
[52] Y Takahashi Latent heat measurement by DSC with sapphire as standard material
Thermochim Acta 88(1) 1985 199-204
101
[53] GW Hohne W Hemminger and HJ Flammersheim Differential Scanning Calorimetry
Springer-Verlag Berlin 1996
[54] W Hemminger and G Hohne Calorimetry Fundamentals and Practice Verlag Weinheim
1984
[55] M Merzlyakov and C Schick Thermal conductivity from dynamic response of DSC
Thermochimica Acta 377 2001 183-191
[56] T Kousksou A Jamil S Gibout and Y Zeraouli Thermal analysis of phase change
emulsion Journal of Thermal Analysis and Calorimetry 96 2009 841-852
[57] A Jamil T Kousksou K El Omari Y Zeraouli and Y Le Guer Heat transfer in salt
solutions enclosed in DSC cells Thermochimica Acta 507-508 2010 15-20
[58] MJ Richardson Quantitative aspects of differential scanning calorimetry Thermochimica
Acta 300 1997 15-28
[59] S Rudtsch Uncertainty of heat capacity measurements with differential scanning
calorimeters Thermochimica Acta 382 2002 17-25
[60] M J Maeso and J Largo The phase diagram of LiNO3-NaNO3 and LiNO3-KNO3 the
behavior of liquid mixtures Thermochimica Acta 223 (1993) 145-156
[61] O J Kleppa A new twin high-temperature reaction calorimeter The heats of mixing in
liquid sodium-potassium nitrates Journal of Physical Chemistry 64(12) (1960) 1937-1940
[62] G W H Hhne H K Cammenga W Eysel E Gmelin and W Hemminger The
Temperature Calibration of Scanning Calorimeters Thermochimica Acta 160 1990 1-12
[63] L B Pankratz Thermodynamic Properties of Carbides Nitrides and Other Selected
Substances U S Bureau of Mines Bulletin 696 1994
[64] M Zhang and R G Reddy Thermodynamic properties of C4mim[Tf2N] ionic liquids 0 2
2010 71-76
102
[65] D Mantha T Wang and R G Reddy Thermodynamic Modeling of Eutectic Point in the
LiNO3-NaNO3-KNO3 Ternary System Journal of Phase Equilibria and Diffusion 2011
(accepted)
[66] R G Reddy T Wang and D Mantha Determination of thermodynamic properties of
2KNO3Mg(NO3)2 Thermochimica Acta 2011 (submitted)
[67] T Wang D Mantha and R G Reddy Thermal stability of new LiNO3-NaNO3-KNO3
ternary salt for thermal energy storage system (in preparation)
[68] G D Carvalho E Frollini and W N D Santos Thermal conductivity of polymers by hot-
wire method J Appl Poly Sci 62 (1996) 2281-2285
[69] H Bloom A Doroszkowski and S B Tricklebank Molten salt mixtures IX The thermal
conductivities of molten nitrate systems Aus J Chem 18(8) (1965) 1171-1176
[70] A G Turnbull Thermal conductivity of molten salts Aus J Appl Sci 12 (1961) 30-41
[71] L R White and H T Davis Thermal conductivity of molten alkali nitrates J Chem Phys
47(1967) 5433-5439
[72] M V Peralta-Martinez M J Assael M J Dix L Karagiannidis and W A Wakeham A
Novel Instrument for the Measurement of the Thermal Conductivity of Molten Metal Part1
Instrument‟s Description Int J Thermophysics 27 (2006) 353-375
[73] Y Tada M Harada M Tanlgakl and W Eguchl Laser Flash Method for Measuring
Thermal Conductivity of Liquids Application to Molten Salts Industrial and Engineering
Chemistry Fundamentals 20 1981 333- 336
[74] M V Smirnov V A Khokhlov and E S Filatov Thermal conductivity of molten alkali
halides and their mixtures Electrochimica Acta 32 (1986) 1019-1026
[75] E Marti E Kaisersberger and W D Emmerich NEW ASPECTS OF THERMAL
ANALYSIS Part I Resolution of DSC and means for its optimization Journal of Thermal
Analysis and Calorimetry 77 2004 905-934
103
[76] E Marti E Kaisersberger G Kaiser and WY Ma Netzsch Annual 2000
bdquoThermoanalytical Characterization of Pharmaceuticals‟ Netzsch-Geraumltebau GmbH D-95100
SelbBavaria
[77] P J van Ekeren C M Holl and A J Witteveen A comparative test of differential
scanning calorimeters Journal of Thermal Analysis and Calorimetry 49 1997 1105-1114
[78] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation
Equations for Critically Evaluated Density Surface Tension Electrical Conductance and
Viscosity Data Journal of Physical and Chemical Reference Data 17 1988 1
[79] G F Petersen W A Ewing and G P Smith ldquoDensities of Some Salt Mixturesrdquo Journal of
Chemical and Engineering Data 6 1961 540
[80] P M Nasch and S G Steinemann Density and Thermal Expansion of Molten Manganese
Iron Nickel Copper Aluminum and Tin by Means of the Gamma-Ray Attenuation Technique
Physics and Chemistry of Liquids 29 1995 43-58
[81] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical and Engineering Data 6 1961 493-496
[82] D A Nissen Thermophysical Properties of the Equimolar Mixture NaNO3-KNO3 from
300degC to 600degC Journal of Chemical and Engineering Data 27 1982 269-273
[83] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate
Mixtures Journal of Chemical and Engineering Data 8 1963 469
104
APPENDIX
Appendix A
Table A1 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in solid state
(29815-40315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 342 1290 417 -025
299 027 008 000 343 1317 426 -026
300 059 018 000 344 1345 436 -027
301 091 028 000 345 1372 445 -028
302 123 037 000 346 1399 455 -029
303 154 047 000 347 1427 464 -031
304 186 056 000 348 1454 474 -032
305 217 066 000 349 1481 483 -033
306 248 076 000 350 1508 493 -035
307 279 085 000 351 1535 503 -036
308 310 095 -001 352 1562 512 -038
309 340 104 -001 353 1589 522 -039
310 371 114 -001 354 1616 532 -041
311 401 123 -001 355 1643 541 -042
312 432 133 -002 356 1670 551 -044
313 462 142 -002 357 1697 561 -045
314 492 152 -002 358 1724 570 -047
315 521 161 -003 359 1751 580 -048
316 551 171 -003 360 1777 590 -050
317 581 180 -004 361 1804 600 -052
318 610 190 -004 362 1831 610 -053
319 640 199 -005 363 1858 619 -055
320 669 209 -005 364 1885 629 -057
105
321 698 218 -006 365 1911 639 -059
322 727 228 -007 366 1938 649 -060
323 756 237 -007 367 1965 659 -062
324 785 246 -008 368 1992 669 -064
325 814 256 -009 369 2018 679 -066
326 842 265 -009 370 2045 689 -068
327 871 275 -010 371 2072 699 -070
328 899 284 -011 372 2098 709 -072
329 928 294 -012 373 2125 719 -074
330 956 303 -012 374 2152 729 -076
331 984 313 -013 375 2179 739 -078
332 1012 322 -014 376 2205 750 -080
333 1041 331 -015 377 2232 760 -082
334 1069 341 -016 378 2259 770 -084
335 1096 350 -017 379 2286 780 -086
336 1124 360 -018 380 2312 791 -088
337 1152 369 -019 381 2339 801 -090
338 1180 379 -020 382 2366 811 -093
339 1207 388 -021 383 2393 822 -095
340 1235 398 -022 384 2420 832 -097
341 1263 407 -023 38415 2424 834 -097
Table A2 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in liquid state
(40315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
40315 4287 1565 -163 514 7070 2838 -796
404 4310 1575 -167 515 7094 2850 -803
405 4337 1585 -171 516 7117 2863 -810
406 4363 1596 -175 517 7141 2875 -817
407 4390 1607 -180 518 7165 2887 -824
408 4417 1618 -184 519 7188 2899 -831
409 4443 1629 -189 520 7212 2911 -839
410 4470 1640 -193 521 7235 2924 -846
411 4496 1651 -197 522 7259 2936 -853
412 4523 1662 -202 523 7282 2948 -860
106
413 4549 1672 -206 524 7306 2960 -868
414 4576 1683 -211 525 7329 2973 -875
415 4602 1694 -216 526 7352 2985 -882
416 4629 1705 -220 527 7376 2997 -890
417 4655 1716 -225 528 7399 3010 -897
418 4681 1727 -230 529 7422 3022 -904
419 4708 1738 -234 530 7446 3034 -912
420 4734 1749 -239 531 7469 3047 -919
421 4760 1760 -244 532 7492 3059 -927
422 4786 1771 -249 533 7516 3071 -934
423 4813 1782 -253 534 7539 3084 -942
424 4839 1793 -258 535 7562 3096 -949
425 4865 1804 -263 536 7585 3109 -957
426 4891 1816 -268 537 7608 3121 -965
427 4917 1827 -273 538 7632 3134 -972
428 4943 1838 -278 539 7655 3146 -980
429 4969 1849 -283 540 7678 3158 -988
430 4995 1860 -288 541 7701 3171 -995
431 5021 1871 -293 542 7724 3183 -1003
432 5046 1882 -298 543 7747 3196 -1011
433 5072 1894 -303 544 7770 3208 -1018
434 5098 1905 -308 545 7793 3221 -1026
435 5124 1916 -313 546 7816 3233 -1034
436 5149 1927 -318 547 7839 3246 -1042
437 5175 1938 -323 548 7862 3259 -1050
438 5201 1950 -328 549 7885 3271 -1058
439 5226 1961 -334 550 7908 3284 -1066
440 5252 1972 -339 551 7931 3296 -1073
441 5278 1983 -344 552 7953 3309 -1081
442 5303 1995 -349 553 7976 3322 -1089
443 5329 2006 -355 554 7999 3334 -1097
444 5354 2017 -360 555 8022 3347 -1105
445 5380 2028 -365 556 8045 3359 -1113
446 5405 2040 -371 557 8067 3372 -1121
447 5430 2051 -376 558 8090 3385 -1130
448 5456 2062 -382 559 8113 3398 -1138
449 5481 2074 -387 560 8136 3410 -1146
450 5506 2085 -393 561 8158 3423 -1154
451 5532 2097 -398 562 8181 3436 -1162
452 5557 2108 -404 563 8204 3448 -1170
107
453 5582 2119 -409 564 8226 3461 -1178
454 5607 2131 -415 565 8249 3474 -1187
455 5633 2142 -421 566 8271 3487 -1195
456 5658 2154 -426 567 8294 3499 -1203
457 5683 2165 -432 568 8317 3512 -1212
458 5708 2177 -438 569 8339 3525 -1220
459 5733 2188 -443 570 8362 3538 -1228
460 5758 2200 -449 571 8384 3551 -1237
461 5783 2211 -455 572 8407 3564 -1245
462 5808 2223 -461 573 8429 3576 -1253
463 5833 2234 -466 574 8452 3589 -1262
464 5858 2246 -472 575 8474 3602 -1270
465 5883 2257 -478 576 8496 3615 -1279
466 5907 2269 -484 577 8519 3628 -1287
467 5932 2280 -490 578 8541 3641 -1296
468 5957 2292 -496 579 8564 3654 -1304
469 5982 2304 -502 580 8586 3667 -1313
470 6007 2315 -508 581 8608 3680 -1322
471 6031 2327 -514 582 8631 3693 -1330
472 6056 2339 -520 583 8653 3706 -1339
473 6081 2350 -526 584 8675 3719 -1348
474 6105 2362 -532 585 8697 3732 -1356
475 6130 2373 -538 586 8720 3745 -1365
476 6155 2385 -544 587 8742 3758 -1374
477 6179 2397 -551 588 8764 3771 -1382
478 6204 2409 -557 589 8786 3784 -1391
479 6228 2420 -563 590 8808 3797 -1400
480 6253 2432 -569 591 8831 3810 -1409
481 6277 2444 -575 592 8853 3823 -1418
482 6301 2456 -582 593 8875 3836 -1426
483 6326 2467 -588 594 8897 3849 -1435
484 6350 2479 -594 595 8919 3863 -1444
485 6375 2491 -601 596 8941 3876 -1453
486 6399 2503 -607 597 8963 3889 -1462
487 6423 2515 -614 598 8985 3902 -1471
488 6448 2526 -620 599 9007 3915 -1480
489 6472 2538 -626 600 9029 3928 -1489
490 6496 2550 -633 601 9051 3942 -1498
491 6520 2562 -639 602 9073 3955 -1507
492 6544 2574 -646 603 9095 3968 -1516
108
493 6569 2586 -653 604 9117 3981 -1525
494 6593 2598 -659 605 9139 3994 -1535
495 6617 2610 -666 606 9161 4008 -1544
496 6641 2621 -672 607 9183 4021 -1553
497 6665 2633 -679 608 9205 4034 -1562
498 6689 2645 -686 609 9226 4048 -1571
499 6713 2657 -692 610 9248 4061 -1581
500 6737 2669 -699 611 9270 4074 -1590
501 6761 2681 -706 612 9292 4088 -1599
502 6785 2693 -713 613 9314 4101 -1608
503 6809 2705 -719 614 9335 4114 -1618
504 6833 2717 -726 615 9357 4128 -1627
505 6856 2729 -733 616 9379 4141 -1636
506 6880 2741 -740 617 9401 4154 -1646
507 6904 2754 -747 618 9422 4168 -1655
508 6928 2766 -754 619 9444 4181 -1665
509 6952 2778 -761 620 9466 4195 -1674
510 6975 2790 -768 621 9487 4208 -1684
511 6999 2802 -775 622 9509 4222 -1693
512 7023 2814 -782 623 9531 4235 -1703
513 7047 2826 -789 62315 9534 4237 -1704
109
Appendix B
Table B1 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(29815-39215K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 347 1233 382 -046
299 022 006 000 348 1258 390 -048
300 049 014 -001 349 1283 398 -049
301 075 022 -001 350 1307 406 -051
302 101 029 -001 351 1332 415 -053
303 127 037 -002 352 1356 423 -054
304 153 044 -002 353 1381 431 -056
305 179 052 -003 354 1405 440 -058
306 205 059 -003 355 1430 448 -060
307 230 067 -004 356 1455 456 -061
308 256 075 -004 357 1479 465 -063
309 282 082 -005 358 1504 473 -065
310 308 090 -005 359 1528 482 -067
311 333 098 -006 360 1553 490 -069
312 359 105 -007 361 1577 498 -071
313 384 113 -007 362 1602 507 -073
314 410 121 -008 363 1626 515 -075
315 435 128 -009 364 1651 524 -077
316 461 136 -010 365 1675 533 -079
317 486 144 -010 366 1700 541 -081
318 511 151 -011 367 1724 550 -083
319 537 159 -012 368 1749 558 -085
320 562 167 -013 369 1773 567 -087
321 587 175 -014 370 1798 576 -089
322 612 182 -015 371 1822 584 -092
323 637 190 -016 372 1847 593 -094
324 663 198 -017 373 1871 602 -096
325 688 206 -018 374 1896 611 -098
326 713 214 -019 375 1920 620 -100
327 738 222 -020 376 1945 628 -103
328 763 229 -021 377 1969 637 -105
329 788 237 -022 378 1994 646 -107
110
330 813 245 -023 379 2018 655 -110
331 838 253 -024 380 2043 664 -112
332 863 261 -025 381 2068 673 -115
333 887 269 -027 382 2092 682 -117
334 912 277 -028 383 2117 691 -120
335 937 285 -029 384 2141 700 -122
336 962 293 -030 385 2166 709 -125
337 987 301 -032 386 2191 718 -127
338 1011 309 -033 387 2215 727 -130
339 1036 317 -034 388 2240 737 -132
340 1061 325 -036 389 2265 746 -135
341 1086 333 -037 390 2289 755 -138
342 1110 341 -039 391 2314 764 -140
343 1135 349 -040 392 2339 774 -143
344 1160 357 -042 39215 2342 775 -144
345 1184 365 -043
Table B2 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(41315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
414 3280 1149 -209 520 5608 2235 -682
415 3302 1158 -212 521 5630 2246 -687
416 3325 1167 -216 522 5651 2257 -693
417 3348 1177 -219 523 5672 2268 -698
418 3370 1186 -223 524 5694 2279 -704
419 3393 1196 -226 525 5715 2290 -710
420 3416 1205 -229 526 5736 2302 -716
421 3438 1215 -233 527 5757 2313 -721
422 3461 1224 -236 528 5779 2324 -727
423 3483 1234 -240 529 5800 2335 -733
424 3506 1243 -243 530 5821 2347 -739
425 3529 1253 -247 531 5842 2358 -745
426 3551 1263 -250 532 5864 2369 -750
427 3574 1272 -254 533 5885 2380 -756
428 3596 1282 -257 534 5906 2392 -762
429 3619 1291 -261 535 5927 2403 -768
111
430 3641 1301 -265 536 5948 2414 -774
431 3663 1311 -268 537 5970 2426 -780
432 3686 1320 -272 538 5991 2437 -786
433 3708 1330 -276 539 6012 2449 -792
434 3731 1340 -279 540 6033 2460 -798
435 3753 1350 -283 541 6054 2471 -804
436 3775 1359 -287 542 6075 2483 -810
437 3798 1369 -291 543 6096 2494 -816
438 3820 1379 -294 544 6118 2506 -822
439 3842 1389 -298 545 6139 2517 -828
440 3865 1398 -302 546 6160 2529 -835
441 3887 1408 -306 547 6181 2540 -841
442 3909 1418 -310 548 6202 2552 -847
443 3932 1428 -314 549 6223 2563 -853
444 3954 1438 -318 550 6244 2575 -859
445 3976 1448 -322 551 6265 2586 -866
446 3998 1458 -326 552 6286 2598 -872
447 4021 1468 -330 553 6307 2610 -878
448 4043 1477 -334 554 6328 2621 -884
449 4065 1487 -338 555 6349 2633 -891
450 4087 1497 -342 556 6370 2645 -897
451 4109 1507 -346 557 6391 2656 -904
452 4131 1517 -350 558 6412 2668 -910
453 4154 1527 -354 559 6433 2680 -916
454 4176 1537 -358 560 6454 2691 -923
455 4198 1547 -363 561 6475 2703 -929
456 4220 1557 -367 562 6496 2715 -936
457 4242 1568 -371 563 6517 2727 -942
458 4264 1578 -375 564 6538 2738 -949
459 4286 1588 -380 565 6559 2750 -955
460 4308 1598 -384 566 6580 2762 -962
461 4330 1608 -388 567 6600 2774 -969
462 4352 1618 -393 568 6621 2786 -975
463 4374 1628 -397 569 6642 2798 -982
464 4396 1639 -401 570 6663 2810 -988
465 4418 1649 -406 571 6684 2821 -995
466 4440 1659 -410 572 6705 2833 -1002
467 4462 1669 -415 573 6726 2845 -1009
468 4484 1680 -419 574 6747 2857 -1015
469 4506 1690 -424 575 6767 2869 -1022
112
470 4528 1700 -428 576 6788 2881 -1029
471 4550 1710 -433 577 6809 2893 -1036
472 4572 1721 -437 578 6830 2905 -1042
473 4593 1731 -442 579 6851 2917 -1049
474 4615 1741 -446 580 6871 2929 -1056
475 4637 1752 -451 581 6892 2941 -1063
476 4659 1762 -456 582 6913 2953 -1070
477 4681 1773 -460 583 6934 2966 -1077
478 4703 1783 -465 584 6954 2978 -1084
479 4724 1793 -470 585 6975 2990 -1091
480 4746 1804 -474 586 6996 3002 -1098
481 4768 1814 -479 587 7017 3014 -1105
482 4790 1825 -484 588 7037 3026 -1112
483 4812 1835 -489 589 7058 3038 -1119
484 4833 1846 -494 590 7079 3051 -1126
485 4855 1856 -498 591 7100 3063 -1133
486 4877 1867 -503 592 7120 3075 -1140
487 4898 1877 -508 593 7141 3087 -1147
488 4920 1888 -513 594 7162 3100 -1154
489 4942 1899 -518 595 7182 3112 -1162
490 4963 1909 -523 596 7203 3124 -1169
491 4985 1920 -528 597 7224 3137 -1176
492 5007 1930 -533 598 7244 3149 -1183
493 5028 1941 -538 599 7265 3161 -1190
494 5050 1952 -543 600 7285 3174 -1198
495 5072 1962 -548 601 7306 3186 -1205
496 5093 1973 -553 602 7327 3198 -1212
497 5115 1984 -558 603 7347 3211 -1220
498 5136 1995 -563 604 7368 3223 -1227
499 5158 2005 -568 605 7389 3236 -1234
500 5180 2016 -574 606 7409 3248 -1242
501 5201 2027 -579 607 7430 3261 -1249
502 5223 2038 -584 608 7450 3273 -1257
503 5244 2049 -589 609 7471 3286 -1264
504 5266 2059 -595 610 7491 3298 -1272
505 5287 2070 -600 611 7512 3311 -1279
506 5309 2081 -605 612 7532 3323 -1287
507 5330 2092 -610 613 7553 3336 -1294
508 5352 2103 -616 614 7573 3348 -1302
509 5373 2114 -621 615 7594 3361 -1309
113
510 5394 2125 -627 616 7615 3374 -1317
511 5416 2136 -632 617 7635 3386 -1325
512 5437 2147 -637 618 7656 3399 -1332
513 5459 2158 -643 619 7676 3412 -1340
514 5480 2169 -648 620 7696 3424 -1348
515 5502 2180 -654 621 7717 3437 -1355
516 5523 2191 -659 622 7737 3450 -1363
517 5544 2202 -665 623 7758 3462 -1371
518 5566 2213 -670 62315 7761 3464 -1372
114
Appendix C
Table C1 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in solid
state (29815-36415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 333 1937 611 -034
299 048 014 000 334 1992 629 -036
300 104 031 000 335 2047 647 -038
301 160 048 000 336 2102 666 -040
302 216 065 000 337 2156 684 -042
303 272 082 -001 338 2211 703 -045
304 329 099 -001 339 2266 721 -047
305 385 116 -001 340 2321 740 -049
306 441 133 -002 341 2375 758 -052
307 496 150 -002 342 2430 777 -054
308 552 167 -003 343 2485 796 -056
309 608 185 -003 344 2539 815 -059
310 664 202 -004 345 2594 833 -062
311 720 219 -005 346 2648 852 -064
312 776 236 -006 347 2703 871 -067
313 831 254 -006 348 2757 890 -070
314 887 271 -007 349 2812 909 -072
315 942 289 -008 350 2866 928 -075
316 998 306 -009 351 2921 947 -078
317 1054 324 -010 352 2975 966 -081
318 1109 341 -011 353 3029 985 -084
319 1164 359 -012 354 3084 1004 -087
320 1220 377 -014 355 3138 1024 -090
321 1275 395 -015 356 3192 1043 -094
322 1331 412 -016 357 3246 1062 -097
323 1386 430 -018 358 3300 1082 -100
324 1441 448 -019 359 3355 1101 -103
325 1496 466 -020 360 3409 1120 -107
326 1552 484 -022 361 3463 1140 -110
327 1607 502 -024 362 3517 1159 -114
328 1662 520 -025 363 3571 1179 -117
329 1717 538 -027 364 3625 1199 -121
115
330 1772 556 -029 36415 3633 1202 -121
331 1827 574 -030
332 1882 593 -032
Table C2 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in liquid
state (42115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
42115 7428 2673 -455 523 11788 4725 -1440
422 7468 2690 -461 524 11827 4745 -1452
423 7515 2710 -468 525 11866 4766 -1464
424 7562 2730 -476 526 11904 4786 -1476
425 7608 2750 -484 527 11943 4807 -1488
426 7655 2770 -491 528 11982 4827 -1500
427 7702 2790 -499 529 12021 4847 -1512
428 7748 2810 -507 530 12059 4868 -1524
429 7795 2830 -514 531 12098 4888 -1536
430 7841 2849 -522 532 12137 4909 -1548
431 7887 2869 -530 533 12175 4929 -1560
432 7933 2889 -538 534 12213 4950 -1572
433 7979 2909 -546 535 12252 4970 -1584
434 8025 2929 -554 536 12290 4991 -1597
435 8071 2949 -562 537 12328 5011 -1609
436 8117 2969 -570 538 12366 5032 -1621
437 8163 2989 -578 539 12404 5052 -1634
438 8208 3009 -586 540 12442 5073 -1646
439 8254 3029 -595 541 12480 5093 -1659
440 8299 3049 -603 542 12518 5114 -1671
441 8345 3069 -611 543 12556 5134 -1684
442 8390 3089 -620 544 12594 5155 -1696
443 8435 3109 -628 545 12632 5175 -1709
444 8480 3129 -636 546 12669 5196 -1721
445 8525 3149 -645 547 12707 5217 -1734
446 8570 3169 -654 548 12745 5237 -1747
116
447 8615 3189 -662 549 12782 5258 -1760
448 8659 3209 -671 550 12820 5278 -1772
449 8704 3229 -679 551 12857 5299 -1785
450 8748 3249 -688 552 12894 5319 -1798
451 8793 3269 -697 553 12932 5340 -1811
452 8837 3289 -706 554 12969 5361 -1824
453 8881 3309 -715 555 13006 5381 -1837
454 8926 3329 -724 556 13043 5402 -1850
455 8970 3349 -732 557 13080 5422 -1863
456 9014 3369 -741 558 13117 5443 -1876
457 9058 3389 -750 559 13154 5464 -1889
458 9102 3409 -760 560 13191 5484 -1902
459 9145 3429 -769 561 13228 5505 -1916
460 9189 3449 -778 562 13264 5526 -1929
461 9233 3469 -787 563 13301 5546 -1942
462 9276 3489 -796 564 13338 5567 -1956
463 9319 3509 -806 565 13374 5588 -1969
464 9363 3529 -815 566 13411 5608 -1982
465 9406 3549 -824 567 13447 5629 -1996
466 9449 3570 -834 568 13484 5650 -2009
467 9492 3590 -843 569 13520 5670 -2023
468 9535 3610 -853 570 13557 5691 -2036
469 9578 3630 -862 571 13593 5712 -2050
470 9621 3650 -872 572 13629 5732 -2063
471 9664 3670 -882 573 13665 5753 -2077
472 9707 3690 -891 574 13701 5774 -2091
473 9749 3710 -901 575 13737 5795 -2104
474 9792 3731 -911 576 13773 5815 -2118
475 9834 3751 -921 577 13809 5836 -2132
476 9877 3771 -930 578 13845 5857 -2146
477 9919 3791 -940 579 13881 5877 -2160
478 9961 3811 -950 580 13917 5898 -2174
479 10004 3831 -960 581 13953 5919 -2188
480 10046 3852 -970 582 13988 5940 -2202
481 10088 3872 -980 583 14024 5960 -2216
482 10130 3892 -990 584 14060 5981 -2230
483 10171 3912 -1001 585 14095 6002 -2244
484 10213 3932 -1011 586 14131 6023 -2258
485 10255 3953 -1021 587 14166 6044 -2272
486 10297 3973 -1031 588 14201 6064 -2286
117
487 10338 3993 -1042 589 14237 6085 -2300
488 10380 4013 -1052 590 14272 6106 -2315
489 10421 4034 -1062 591 14307 6127 -2329
490 10462 4054 -1073 592 14342 6148 -2343
491 10504 4074 -1083 593 14378 6168 -2358
492 10545 4094 -1094 594 14413 6189 -2372
493 10586 4114 -1104 595 14448 6210 -2386
494 10627 4135 -1115 596 14483 6231 -2401
495 10668 4155 -1126 597 14518 6252 -2415
496 10709 4175 -1136 598 14552 6273 -2430
497 10750 4196 -1147 599 14587 6293 -2444
498 10791 4216 -1158 600 14622 6314 -2459
499 10831 4236 -1169 601 14657 6335 -2474
500 10872 4256 -1179 602 14692 6356 -2488
501 10912 4277 -1190 603 14726 6377 -2503
502 10953 4297 -1201 604 14761 6398 -2518
503 10993 4317 -1212 605 14795 6419 -2533
504 11034 4338 -1223 606 14830 6439 -2547
505 11074 4358 -1234 607 14864 6460 -2562
506 11114 4378 -1245 608 14899 6481 -2577
507 11154 4399 -1257 609 14933 6502 -2592
508 11194 4419 -1268 610 14967 6523 -2607
509 11234 4439 -1279 611 15002 6544 -2622
510 11274 4460 -1290 612 15036 6565 -2637
511 11314 4480 -1302 613 15070 6586 -2652
512 11354 4500 -1313 614 15104 6607 -2667
513 11394 4521 -1324 615 15138 6628 -2682
514 11433 4541 -1336 616 15172 6649 -2697
515 11473 4562 -1347 617 15206 6670 -2713
516 11513 4582 -1359 618 15240 6691 -2728
517 11552 4602 -1370 619 15274 6712 -2743
518 11591 4623 -1382 620 15308 6733 -2758
519 11631 4643 -1393 621 15342 6754 -2774
520 11670 4664 -1405 622 15375 6774 -2789
521 11709 4684 -1417 623 15409 6795 -2804
522 11748 4704 -1428 62315 15414 6799 -2807
118
Appendix D
Table D1 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in solid state
(29815-36315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
299 021 006 000 333 867 277 -012
300 047 014 000 334 891 285 -012
301 072 022 000 335 916 293 -013
302 097 029 000 336 940 302 -014
303 122 037 000 337 964 310 -015
304 147 045 000 338 989 318 -016
305 172 053 000 339 1013 327 -017
306 197 060 000 340 1037 335 -018
307 223 068 000 341 1061 343 -019
308 248 076 000 342 1085 352 -019
309 273 084 000 343 1109 360 -020
310 298 092 -001 344 1134 369 -021
311 323 099 -001 345 1158 377 -022
312 348 107 -001 346 1182 385 -024
313 373 115 -001 347 1206 394 -025
314 398 123 -002 348 1230 402 -026
315 423 131 -002 349 1254 411 -027
316 447 139 -002 350 1277 419 -028
317 472 147 -003 351 1301 428 -029
318 497 155 -003 352 1325 436 -030
319 522 163 -003 353 1349 445 -032
320 547 171 -004 354 1373 453 -033
321 572 179 -004 355 1396 462 -034
322 596 187 -005 356 1420 470 -035
323 621 195 -005 357 1444 479 -037
324 646 203 -006 358 1467 487 -038
325 670 211 -006 359 1491 496 -039
326 695 220 -007 360 1514 504 -041
327 720 228 -008 361 1538 513 -042
328 744 236 -008 362 1561 522 -043
329 769 244 -009 363 1584 530 -045
330 793 252 -010 36315 1588 532 -045
119
331 818 260 -010
Table D2 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in liquid
state (38115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
38115 2281 765 -104 503 5639 2242 -594
382 2307 775 -106 504 5664 2255 -600
383 2338 787 -109 505 5689 2267 -606
384 2369 798 -111 506 5713 2280 -611
385 2399 810 -113 507 5738 2292 -617
386 2430 822 -116 508 5763 2305 -623
387 2460 834 -118 509 5787 2317 -629
388 2491 846 -121 510 5812 2330 -634
389 2521 857 -123 511 5836 2342 -640
390 2551 869 -126 512 5861 2355 -646
391 2582 881 -128 513 5885 2367 -652
392 2612 893 -131 514 5910 2380 -658
393 2642 905 -134 515 5934 2392 -664
394 2672 917 -136 516 5959 2405 -670
395 2702 928 -139 517 5983 2417 -676
396 2732 940 -142 518 6007 2430 -682
397 2762 952 -144 519 6032 2443 -688
398 2792 964 -147 520 6056 2455 -694
399 2821 976 -150 521 6080 2468 -700
400 2851 988 -153 522 6104 2480 -706
401 2881 999 -156 523 6128 2493 -712
402 2910 1011 -159 524 6152 2506 -718
403 2940 1023 -162 525 6176 2518 -724
404 2969 1035 -164 526 6200 2531 -731
405 2999 1047 -167 527 6224 2544 -737
406 3028 1059 -170 528 6248 2556 -743
407 3057 1071 -174 529 6272 2569 -749
408 3087 1083 -177 530 6296 2581 -756
120
409 3116 1095 -180 531 6320 2594 -762
410 3145 1107 -183 532 6344 2607 -768
411 3174 1119 -186 533 6368 2619 -775
412 3203 1130 -189 534 6391 2632 -781
413 3232 1142 -192 535 6415 2645 -787
414 3261 1154 -196 536 6439 2657 -794
415 3290 1166 -199 537 6462 2670 -800
416 3319 1178 -202 538 6486 2683 -807
417 3347 1190 -206 539 6510 2696 -813
418 3376 1202 -209 540 6533 2708 -820
419 3405 1214 -212 541 6557 2721 -826
420 3433 1226 -216 542 6580 2734 -833
421 3462 1238 -219 543 6604 2746 -839
422 3490 1250 -223 544 6627 2759 -846
423 3519 1262 -226 545 6650 2772 -853
424 3547 1274 -230 546 6674 2785 -859
425 3575 1286 -233 547 6697 2797 -866
426 3604 1298 -237 548 6720 2810 -873
427 3632 1310 -240 549 6744 2823 -879
428 3660 1322 -244 550 6767 2836 -886
429 3688 1334 -248 551 6790 2848 -893
430 3716 1346 -251 552 6813 2861 -900
431 3744 1358 -255 553 6836 2874 -907
432 3772 1371 -259 554 6860 2887 -913
433 3800 1383 -263 555 6883 2900 -920
434 3828 1395 -267 556 6906 2912 -927
435 3856 1407 -270 557 6929 2925 -934
436 3883 1419 -274 558 6952 2938 -941
437 3911 1431 -278 559 6975 2951 -948
438 3939 1443 -282 560 6998 2964 -955
439 3966 1455 -286 561 7020 2976 -962
440 3994 1467 -290 562 7043 2989 -969
441 4021 1479 -294 563 7066 3002 -976
442 4049 1491 -298 564 7089 3015 -983
443 4076 1504 -302 565 7112 3028 -990
444 4103 1516 -306 566 7134 3041 -997
445 4131 1528 -310 567 7157 3054 -1005
446 4158 1540 -314 568 7180 3066 -1012
447 4185 1552 -319 569 7203 3079 -1019
448 4212 1564 -323 570 7225 3092 -1026
121
449 4240 1576 -327 571 7248 3105 -1033
450 4267 1589 -331 572 7270 3118 -1041
451 4294 1601 -336 573 7293 3131 -1048
452 4321 1613 -340 574 7315 3144 -1055
453 4347 1625 -344 575 7338 3157 -1063
454 4374 1637 -349 576 7360 3170 -1070
455 4401 1650 -353 577 7383 3183 -1077
456 4428 1662 -357 578 7405 3196 -1085
457 4455 1674 -362 579 7428 3208 -1092
458 4481 1686 -366 580 7450 3221 -1100
459 4508 1698 -371 581 7472 3234 -1107
460 4535 1711 -375 582 7494 3247 -1114
461 4561 1723 -380 583 7517 3260 -1122
462 4588 1735 -384 584 7539 3273 -1129
463 4614 1747 -389 585 7561 3286 -1137
464 4641 1760 -394 586 7583 3299 -1145
465 4667 1772 -398 587 7605 3312 -1152
466 4693 1784 -403 588 7628 3325 -1160
467 4720 1796 -408 589 7650 3338 -1167
468 4746 1809 -412 590 7672 3351 -1175
469 4772 1821 -417 591 7694 3364 -1183
470 4798 1833 -422 592 7716 3377 -1191
471 4825 1846 -427 593 7738 3390 -1198
472 4851 1858 -432 594 7760 3403 -1206
473 4877 1870 -437 595 7782 3416 -1214
474 4903 1882 -441 596 7804 3429 -1222
475 4929 1895 -446 597 7825 3442 -1229
476 4955 1907 -451 598 7847 3455 -1237
477 4980 1919 -456 599 7869 3469 -1245
478 5006 1932 -461 600 7891 3482 -1253
479 5032 1944 -466 601 7913 3495 -1261
480 5058 1956 -471 602 7934 3508 -1269
481 5083 1969 -476 603 7956 3521 -1277
482 5109 1981 -481 604 7978 3534 -1285
483 5135 1994 -487 605 8000 3547 -1293
484 5160 2006 -492 606 8021 3560 -1301
485 5186 2018 -497 607 8043 3573 -1309
486 5211 2031 -502 608 8064 3586 -1317
487 5237 2043 -507 609 8086 3599 -1325
488 5262 2055 -513 610 8107 3613 -1333
122
489 5288 2068 -518 611 8129 3626 -1341
490 5313 2080 -523 612 8150 3639 -1349
491 5338 2093 -528 613 8172 3652 -1357
492 5364 2105 -534 614 8193 3665 -1366
493 5389 2117 -539 615 8215 3678 -1374
494 5414 2130 -545 616 8236 3692 -1382
495 5439 2142 -550 617 8258 3705 -1390
496 5464 2155 -555 618 8279 3718 -1398
497 5489 2167 -561 619 8300 3731 -1407
498 5514 2180 -566 620 8321 3744 -1415
499 5539 2192 -572 621 8343 3757 -1423
500 5564 2205 -578 622 8364 3771 -1432
501 5589 2217 -583 623 8385 3784 -1441
502 5614 2230 -589 62315 8388 3786 -1443
123
Appendix E
Table E1 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in solid state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 913 287 -014
299 025 007 000 331 941 296 -015
300 054 016 000 332 970 306 -016
301 083 025 000 333 998 315 -017
302 112 034 000 334 1026 324 -018
303 141 042 000 335 1054 334 -019
304 170 051 000 336 1081 343 -020
305 199 060 -001 337 1109 353 -021
306 228 069 -001 338 1137 362 -022
307 257 078 -001 339 1165 371 -024
308 286 087 -001 340 1193 381 -025
309 315 096 -002 341 1221 390 -026
310 343 105 -002 342 1248 400 -027
311 372 113 -002 343 1276 409 -028
312 401 122 -003 344 1304 419 -030
313 430 131 -003 345 1331 428 -031
314 458 140 -003 346 1359 438 -032
315 487 149 -004 347 1386 447 -034
316 516 159 -004 348 1414 457 -035
317 544 168 -005 349 1441 466 -036
318 573 177 -006 350 1468 476 -038
319 602 186 -006 351 1496 486 -039
320 630 195 -007 352 1523 495 -041
321 659 204 -007 353 1550 505 -042
322 687 213 -008 354 1577 514 -044
323 715 222 -009 355 1605 524 -046
324 744 232 -009 356 1632 534 -047
325 772 241 -010 357 1659 543 -049
326 800 250 -011 358 1686 553 -050
327 829 259 -012 359 1713 563 -052
328 857 269 -013 35915 1717 564 -052
329 885 278 -013
124
Table E2 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in liquid state (376-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2323 777 -094 500 5525 2173 -590
376 2347 786 -096 501 5548 2184 -595
377 2375 797 -098 502 5572 2196 -601
378 2403 808 -101 503 5595 2208 -606
379 2431 818 -103 504 5619 2220 -612
380 2459 829 -106 505 5642 2232 -618
381 2487 839 -108 506 5665 2243 -623
382 2515 850 -111 507 5689 2255 -629
383 2542 861 -113 508 5712 2267 -635
384 2570 871 -116 509 5735 2279 -640
385 2598 882 -118 510 5759 2291 -646
386 2626 893 -121 511 5782 2303 -652
387 2653 903 -123 512 5805 2315 -658
388 2681 914 -126 513 5828 2326 -664
389 2708 925 -129 514 5852 2338 -669
390 2736 935 -132 515 5875 2350 -675
391 2763 946 -134 516 5898 2362 -681
392 2791 957 -137 517 5921 2374 -687
393 2818 968 -140 518 5944 2386 -693
394 2845 978 -143 519 5967 2398 -699
395 2873 989 -146 520 5990 2410 -705
396 2900 1000 -148 521 6013 2422 -711
397 2927 1011 -151 522 6036 2434 -717
398 2954 1022 -154 523 6059 2446 -723
399 2981 1032 -157 524 6082 2458 -729
400 3008 1043 -160 525 6105 2470 -735
401 3035 1054 -163 526 6128 2482 -741
402 3062 1065 -166 527 6151 2494 -747
403 3089 1076 -169 528 6173 2506 -754
404 3116 1086 -172 529 6196 2518 -760
405 3143 1097 -176 530 6219 2530 -766
125
406 3170 1108 -179 531 6242 2542 -772
407 3197 1119 -182 532 6265 2554 -778
408 3223 1130 -185 533 6287 2566 -785
409 3250 1141 -188 534 6310 2578 -791
410 3277 1152 -192 535 6333 2591 -797
411 3303 1163 -195 536 6355 2603 -804
412 3330 1174 -198 537 6378 2615 -810
413 3356 1185 -202 538 6400 2627 -816
414 3383 1195 -205 539 6423 2639 -823
415 3409 1206 -208 540 6445 2651 -829
416 3436 1217 -212 541 6468 2663 -836
417 3462 1228 -215 542 6490 2676 -842
418 3488 1239 -219 543 6513 2688 -849
419 3515 1250 -222 544 6535 2700 -855
420 3541 1261 -226 545 6558 2712 -862
421 3567 1272 -229 546 6580 2724 -868
422 3593 1283 -233 547 6602 2737 -875
423 3619 1294 -236 548 6625 2749 -882
424 3645 1305 -240 549 6647 2761 -888
425 3671 1317 -244 550 6669 2773 -895
426 3697 1328 -247 551 6692 2786 -902
427 3723 1339 -251 552 6714 2798 -908
428 3749 1350 -255 553 6736 2810 -915
429 3775 1361 -259 554 6758 2822 -922
430 3801 1372 -262 555 6780 2835 -929
431 3827 1383 -266 556 6803 2847 -935
432 3852 1394 -270 557 6825 2859 -942
433 3878 1405 -274 558 6847 2872 -949
434 3904 1416 -278 559 6869 2884 -956
435 3929 1428 -282 560 6891 2896 -963
436 3955 1439 -286 561 6913 2909 -970
437 3981 1450 -290 562 6935 2921 -977
438 4006 1461 -294 563 6957 2933 -983
439 4032 1472 -298 564 6979 2946 -990
440 4057 1483 -302 565 7001 2958 -997
441 4083 1495 -306 566 7023 2971 -1004
442 4108 1506 -310 567 7045 2983 -1011
443 4133 1517 -314 568 7067 2995 -1019
444 4159 1528 -318 569 7089 3008 -1026
445 4184 1540 -322 570 7110 3020 -1033
126
446 4209 1551 -327 571 7132 3033 -1040
447 4234 1562 -331 572 7154 3045 -1047
448 4260 1573 -335 573 7176 3058 -1054
449 4285 1585 -339 574 7198 3070 -1061
450 4310 1596 -344 575 7219 3083 -1069
451 4335 1607 -348 576 7241 3095 -1076
452 4360 1618 -352 577 7263 3108 -1083
453 4385 1630 -357 578 7284 3120 -1090
454 4410 1641 -361 579 7306 3133 -1098
455 4435 1652 -365 580 7328 3145 -1105
456 4460 1664 -370 581 7349 3158 -1112
457 4485 1675 -374 582 7371 3170 -1120
458 4510 1687 -379 583 7393 3183 -1127
459 4534 1698 -383 584 7414 3195 -1134
460 4559 1709 -388 585 7436 3208 -1142
461 4584 1721 -393 586 7457 3221 -1149
462 4609 1732 -397 587 7479 3233 -1157
463 4633 1743 -402 588 7500 3246 -1164
464 4658 1755 -406 589 7522 3258 -1172
465 4683 1766 -411 590 7543 3271 -1179
466 4707 1778 -416 591 7564 3284 -1187
467 4732 1789 -420 592 7586 3296 -1194
468 4756 1801 -425 593 7607 3309 -1202
469 4781 1812 -430 594 7628 3322 -1210
470 4805 1824 -435 595 7650 3334 -1217
471 4830 1835 -440 596 7671 3347 -1225
472 4854 1847 -444 597 7692 3360 -1233
473 4878 1858 -449 598 7714 3373 -1240
474 4903 1870 -454 599 7735 3385 -1248
475 4927 1881 -459 600 7756 3398 -1256
476 4951 1893 -464 601 7777 3411 -1264
477 4975 1904 -469 602 7799 3423 -1271
478 5000 1916 -474 603 7820 3436 -1279
479 5024 1927 -479 604 7841 3449 -1287
480 5048 1939 -484 605 7862 3462 -1295
481 5072 1951 -489 606 7883 3475 -1303
482 5096 1962 -494 607 7904 3487 -1311
483 5120 1974 -499 608 7925 3500 -1318
484 5144 1985 -504 609 7946 3513 -1326
485 5168 1997 -510 610 7967 3526 -1334
127
486 5192 2009 -515 611 7988 3539 -1342
487 5216 2020 -520 612 8009 3551 -1350
488 5240 2032 -525 613 8030 3564 -1358
489 5264 2044 -530 614 8051 3577 -1366
490 5288 2055 -536 615 8072 3590 -1374
491 5312 2067 -541 616 8093 3603 -1383
492 5335 2079 -546 617 8114 3616 -1391
493 5359 2090 -552 618 8135 3629 -1399
494 5383 2102 -557 619 8156 3642 -1407
495 5407 2114 -562 620 8177 3655 -1415
496 5430 2126 -568 621 8198 3667 -1423
497 5454 2137 -573 622 8219 3680 -1431
498 5478 2149 -579 623 8239 3693 -1440
499 5501 2161 -584 62315 8242 3695 -1441
128
Appendix F
Table F1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in solid
state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 1063 334 -017
299 029 009 000 331 1096 345 -018
300 063 019 000 332 1128 356 -019
301 097 029 000 333 1161 366 -020
302 131 039 000 334 1193 377 -021
303 165 050 000 335 1225 388 -022
304 199 060 -001 336 1258 399 -024
305 233 070 -001 337 1290 410 -025
306 267 081 -001 338 1322 421 -026
307 300 091 -001 339 1355 432 -028
308 334 101 -002 340 1387 443 -029
309 368 112 -002 341 1419 454 -030
310 401 122 -002 342 1451 464 -032
311 435 133 -003 343 1483 475 -033
312 468 143 -003 344 1515 486 -035
313 502 153 -004 345 1547 497 -036
314 535 164 -004 346 1578 508 -038
315 569 174 -005 347 1610 519 -039
316 602 185 -005 348 1642 531 -041
317 635 196 -006 349 1674 542 -043
318 668 206 -006 350 1705 553 -044
319 702 217 -007 351 1737 564 -046
320 735 227 -008 352 1769 575 -048
321 768 238 -009 353 1800 586 -049
322 801 248 -009 354 1832 597 -051
323 834 259 -010 355 1863 608 -053
324 867 270 -011 356 1894 619 -055
325 900 280 -012 357 1926 631 -057
326 932 291 -013 358 1957 642 -059
327 965 302 -014 359 1988 653 -061
328 998 313 -015 35915 1993 655 -061
329 1030 323 -016
129
Table F2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in liquid
state (37515-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2691 926 -083 500 6111 2416 -640
376 2717 936 -085 501 6136 2428 -646
377 2747 948 -088 502 6161 2440 -652
378 2778 959 -091 503 6185 2453 -658
379 2808 971 -094 504 6210 2465 -665
380 2838 982 -096 505 6235 2478 -671
381 2869 994 -099 506 6259 2490 -677
382 2899 1005 -102 507 6284 2502 -683
383 2929 1017 -105 508 6308 2515 -690
384 2959 1028 -108 509 6333 2527 -696
385 2989 1040 -111 510 6357 2540 -702
386 3019 1051 -114 511 6381 2552 -709
387 3049 1063 -117 512 6406 2565 -715
388 3079 1075 -120 513 6430 2577 -721
389 3109 1086 -123 514 6454 2590 -728
390 3138 1098 -126 515 6479 2602 -734
391 3168 1109 -129 516 6503 2615 -741
392 3198 1121 -133 517 6527 2627 -747
393 3227 1132 -136 518 6551 2640 -754
394 3257 1144 -139 519 6575 2652 -760
395 3286 1156 -142 520 6599 2665 -767
396 3316 1167 -146 521 6624 2677 -774
397 3345 1179 -149 522 6648 2690 -780
398 3374 1191 -152 523 6672 2702 -787
399 3403 1202 -156 524 6696 2715 -794
400 3433 1214 -159 525 6719 2727 -800
401 3462 1226 -163 526 6743 2740 -807
402 3491 1237 -166 527 6767 2753 -814
403 3520 1249 -170 528 6791 2765 -821
404 3549 1261 -173 529 6815 2778 -827
405 3578 1272 -177 530 6839 2790 -834
130
406 3606 1284 -180 531 6862 2803 -841
407 3635 1296 -184 532 6886 2815 -848
408 3664 1307 -187 533 6910 2828 -855
409 3693 1319 -191 534 6933 2841 -862
410 3721 1331 -195 535 6957 2853 -869
411 3750 1343 -199 536 6981 2866 -876
412 3778 1354 -202 537 7004 2879 -883
413 3807 1366 -206 538 7028 2891 -890
414 3835 1378 -210 539 7051 2904 -897
415 3864 1390 -214 540 7075 2917 -904
416 3892 1401 -218 541 7098 2929 -911
417 3920 1413 -222 542 7122 2942 -918
418 3948 1425 -226 543 7145 2955 -925
419 3977 1437 -230 544 7168 2967 -932
420 4005 1449 -234 545 7192 2980 -939
421 4033 1460 -238 546 7215 2993 -947
422 4061 1472 -242 547 7238 3005 -954
423 4089 1484 -246 548 7261 3018 -961
424 4117 1496 -250 549 7285 3031 -968
425 4145 1508 -254 550 7308 3044 -976
426 4172 1519 -258 551 7331 3056 -983
427 4200 1531 -262 552 7354 3069 -990
428 4228 1543 -266 553 7377 3082 -998
429 4256 1555 -271 554 7400 3095 -1005
430 4283 1567 -275 555 7423 3107 -1013
431 4311 1579 -279 556 7446 3120 -1020
432 4338 1591 -284 557 7469 3133 -1027
433 4366 1603 -288 558 7492 3146 -1035
434 4393 1614 -292 559 7515 3159 -1042
435 4421 1626 -297 560 7538 3171 -1050
436 4448 1638 -301 561 7561 3184 -1058
437 4475 1650 -306 562 7584 3197 -1065
438 4503 1662 -310 563 7607 3210 -1073
439 4530 1674 -315 564 7629 3223 -1080
440 4557 1686 -319 565 7652 3235 -1088
441 4584 1698 -324 566 7675 3248 -1096
442 4611 1710 -328 567 7697 3261 -1103
443 4638 1722 -333 568 7720 3274 -1111
444 4665 1734 -338 569 7743 3287 -1119
445 4692 1746 -342 570 7765 3300 -1126
131
446 4719 1758 -347 571 7788 3313 -1134
447 4746 1770 -352 572 7811 3326 -1142
448 4773 1782 -356 573 7833 3338 -1150
449 4800 1794 -361 574 7856 3351 -1158
450 4826 1806 -366 575 7878 3364 -1166
451 4853 1818 -371 576 7901 3377 -1173
452 4880 1830 -376 577 7923 3390 -1181
453 4906 1842 -381 578 7945 3403 -1189
454 4933 1854 -386 579 7968 3416 -1197
455 4959 1866 -391 580 7990 3429 -1205
456 4986 1878 -396 581 8012 3442 -1213
457 5012 1890 -401 582 8035 3455 -1221
458 5039 1902 -406 583 8057 3468 -1229
459 5065 1914 -411 584 8079 3481 -1237
460 5091 1926 -416 585 8101 3494 -1245
461 5118 1938 -421 586 8124 3507 -1254
462 5144 1951 -426 587 8146 3520 -1262
463 5170 1963 -431 588 8168 3533 -1270
464 5196 1975 -436 589 8190 3546 -1278
465 5222 1987 -441 590 8212 3559 -1286
466 5248 1999 -447 591 8234 3572 -1294
467 5274 2011 -452 592 8256 3585 -1303
468 5300 2023 -457 593 8278 3598 -1311
469 5326 2035 -463 594 8300 3611 -1319
470 5352 2048 -468 595 8322 3624 -1328
471 5378 2060 -473 596 8344 3637 -1336
472 5404 2072 -479 597 8366 3650 -1344
473 5430 2084 -484 598 8388 3663 -1353
474 5455 2096 -490 599 8410 3676 -1361
475 5481 2108 -495 600 8432 3690 -1369
476 5507 2121 -500 601 8454 3703 -1378
477 5532 2133 -506 602 8475 3716 -1386
478 5558 2145 -512 603 8497 3729 -1395
479 5583 2157 -517 604 8519 3742 -1403
480 5609 2170 -523 605 8541 3755 -1412
481 5634 2182 -528 606 8562 3768 -1420
482 5660 2194 -534 607 8584 3781 -1429
483 5685 2206 -540 608 8606 3795 -1438
484 5710 2219 -545 609 8627 3808 -1446
485 5736 2231 -551 610 8649 3821 -1455
132
486 5761 2243 -557 611 8670 3834 -1464
487 5786 2255 -563 612 8692 3847 -1472
488 5812 2268 -568 613 8713 3860 -1481
489 5837 2280 -574 614 8735 3874 -1490
490 5862 2292 -580 615 8756 3887 -1498
491 5887 2305 -586 616 8778 3900 -1507
492 5912 2317 -592 617 8799 3913 -1516
493 5937 2329 -598 618 8821 3926 -1525
494 5962 2342 -604 619 8842 3940 -1534
495 5987 2354 -610 620 8864 3953 -1542
496 6012 2366 -616 621 8885 3966 -1551
497 6037 2379 -622 622 8906 3979 -1560
498 6062 2391 -628 623 8928 3993 -1569
499 6086 2403 -634 62315 8931 3995 -1570
133
Appendix G
Table G1 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid I state (29815-33715K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 319 578 162 -004
299 024 000 000 320 606 170 -005
300 052 000 000 321 633 179 -005
301 080 007 000 322 660 188 -006
302 108 016 000 323 688 197 -007
303 136 024 000 324 715 205 -007
304 164 032 000 325 742 214 -008
305 192 041 000 326 769 223 -009
306 219 049 000 327 796 232 -009
307 247 058 000 328 823 241 -010
308 275 067 -001 329 851 250 -011
309 303 075 -001 330 878 259 -011
310 330 084 -001 331 905 268 -012
311 358 092 -001 332 932 277 -013
312 386 101 -002 333 959 285 -014
313 413 109 -002 334 985 294 -015
314 441 118 -002 335 1012 303 -016
315 468 127 -003 336 1039 312 -017
316 496 135 -003 337 1066 321 -018
317 523 144 -003 33715 1070 331 -019
318 551 153 -004
Table G2 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid II state (36115-36415K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36115 2433 825 -054
134
362 2454 832 -056
363 2478 841 -059
364 2503 850 -061
36415 2506 851 -062
Table G3 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
liquid state (41115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
41115 3833 1366 -210 518 6604 2649 -772
412 3857 1376 -213 519 6628 2661 -778
413 3885 1387 -217 520 6652 2674 -785
414 3913 1399 -221 521 6675 2686 -792
415 3941 1411 -225 522 6699 2699 -798
416 3969 1422 -229 523 6723 2711 -805
417 3997 1434 -233 524 6747 2723 -812
418 4025 1446 -237 525 6770 2736 -819
419 4053 1457 -241 526 6794 2748 -825
420 4081 1469 -245 527 6818 2761 -832
421 4109 1481 -249 528 6841 2773 -839
422 4137 1493 -253 529 6865 2786 -846
423 4165 1504 -257 530 6888 2798 -853
424 4192 1516 -262 531 6912 2810 -860
425 4220 1528 -266 532 6935 2823 -867
426 4248 1539 -270 533 6959 2835 -873
427 4275 1551 -274 534 6982 2848 -880
428 4303 1563 -279 535 7005 2860 -887
429 4330 1575 -283 536 7029 2873 -894
430 4358 1587 -287 537 7052 2885 -902
431 4385 1598 -292 538 7075 2898 -909
432 4412 1610 -296 539 7098 2910 -916
433 4439 1622 -300 540 7122 2923 -923
434 4467 1634 -305 541 7145 2935 -930
135
435 4494 1646 -309 542 7168 2948 -937
436 4521 1657 -314 543 7191 2960 -944
437 4548 1669 -318 544 7214 2973 -951
438 4575 1681 -323 545 7237 2986 -959
439 4602 1693 -328 546 7260 2998 -966
440 4629 1705 -332 547 7283 3011 -973
441 4656 1716 -337 548 7306 3023 -980
442 4683 1728 -341 549 7329 3036 -988
443 4710 1740 -346 550 7352 3048 -995
444 4736 1752 -351 551 7375 3061 -1003
445 4763 1764 -356 552 7398 3074 -1010
446 4790 1776 -360 553 7420 3086 -1017
447 4816 1788 -365 554 7443 3099 -1025
448 4843 1800 -370 555 7466 3111 -1032
449 4869 1812 -375 556 7489 3124 -1040
450 4896 1823 -380 557 7511 3137 -1047
451 4922 1835 -385 558 7534 3149 -1055
452 4949 1847 -390 559 7557 3162 -1062
453 4975 1859 -395 560 7579 3175 -1070
454 5002 1871 -400 561 7602 3187 -1077
455 5028 1883 -405 562 7625 3200 -1085
456 5054 1895 -410 563 7647 3213 -1093
457 5080 1907 -415 564 7670 3225 -1100
458 5106 1919 -420 565 7692 3238 -1108
459 5132 1931 -425 566 7714 3251 -1116
460 5159 1943 -430 567 7737 3263 -1123
461 5185 1955 -435 568 7759 3276 -1131
462 5211 1967 -440 569 7782 3289 -1139
463 5236 1979 -446 570 7804 3302 -1147
464 5262 1991 -451 571 7826 3314 -1155
465 5288 2003 -456 572 7849 3327 -1162
466 5314 2015 -461 573 7871 3340 -1170
467 5340 2027 -467 574 7893 3352 -1178
468 5366 2039 -472 575 7915 3365 -1186
469 5391 2051 -478 576 7937 3378 -1194
470 5417 2063 -483 577 7960 3391 -1202
471 5442 2075 -488 578 7982 3404 -1210
472 5468 2087 -494 579 8004 3416 -1218
473 5494 2099 -499 580 8026 3429 -1226
474 5519 2111 -505 581 8048 3442 -1234
136
475 5545 2123 -510 582 8070 3455 -1242
476 5570 2135 -516 583 8092 3468 -1250
477 5595 2147 -521 584 8114 3480 -1258
478 5621 2160 -527 585 8136 3493 -1266
479 5646 2172 -533 586 8158 3506 -1274
480 5671 2184 -538 587 8180 3519 -1283
481 5696 2196 -544 588 8201 3532 -1291
482 5722 2208 -550 589 8223 3545 -1299
483 5747 2220 -555 590 8245 3557 -1307
484 5772 2232 -561 591 8267 3570 -1315
485 5797 2244 -567 592 8289 3583 -1324
486 5822 2257 -573 593 8310 3596 -1332
487 5847 2269 -579 594 8332 3609 -1340
488 5872 2281 -585 595 8354 3622 -1349
489 5897 2293 -590 596 8375 3635 -1357
490 5922 2305 -596 597 8397 3648 -1365
491 5947 2317 -602 598 8419 3660 -1374
492 5971 2330 -608 599 8440 3673 -1382
493 5996 2342 -614 600 8462 3686 -1391
494 6021 2354 -620 601 8483 3699 -1399
495 6046 2366 -626 602 8505 3712 -1408
496 6070 2379 -632 603 8526 3725 -1416
497 6095 2391 -638 604 8548 3738 -1425
498 6119 2403 -645 605 8569 3751 -1433
499 6144 2415 -651 606 8591 3764 -1442
500 6169 2427 -657 607 8612 3777 -1451
501 6193 2440 -663 608 8633 3790 -1459
502 6217 2452 -669 609 8655 3803 -1468
503 6242 2464 -675 610 8676 3816 -1476
504 6266 2477 -682 611 8697 3829 -1485
505 6291 2489 -688 612 8719 3842 -1494
506 6315 2501 -694 613 8740 3855 -1503
507 6339 2513 -701 614 8761 3868 -1511
508 6363 2526 -707 615 8782 3881 -1520
509 6388 2538 -713 616 8803 3894 -1529
510 6412 2550 -720 617 8825 3907 -1538
511 6436 2563 -726 618 8846 3920 -1547
512 6460 2575 -733 619 8867 3933 -1555
513 6484 2587 -739 620 8888 3946 -1564
514 6508 2600 -746 621 8909 3959 -1573
137
515 6532 2612 -752 622 8930 3972 -1582
516 6556 2624 -759 623 8951 3985 -1591
517 6580 2637 -765 62315 8954 3987 -1592
138
Appendix H
Table H1 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid I
state (29815-35415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 768 241 -011
299 023 007 000 328 794 249 -011
300 050 015 000 329 820 258 -012
301 077 023 000 330 846 266 -013
302 104 031 000 331 872 275 -014
303 131 039 000 332 898 284 -015
304 158 048 000 333 924 292 -016
305 185 056 -001 334 950 301 -016
306 212 064 -001 335 976 310 -017
307 239 072 -001 336 1002 318 -018
308 265 081 -001 337 1028 327 -019
309 292 089 -001 338 1053 336 -020
310 319 097 -002 339 1079 344 -021
311 345 105 -002 340 1105 353 -022
312 372 114 -002 341 1130 362 -024
313 399 122 -003 342 1156 371 -025
314 425 130 -003 343 1182 379 -026
315 452 139 -004 344 1207 388 -027
316 478 147 -004 345 1233 397 -028
317 505 156 -004 346 1258 406 -029
318 531 164 -005 347 1284 415 -031
319 558 172 -005 348 1309 424 -032
320 584 181 -006 349 1335 433 -033
321 611 189 -007 350 1360 441 -035
322 637 198 -007 351 1385 450 -036
323 663 206 -008 352 1411 459 -037
324 689 215 -008 353 1436 468 -039
325 716 223 -009 354 1461 477 -040
326 742 232 -010 35415 1465 478 -040
139
Table H2 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid 2
state (36215-37315K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36215 2387 777 -046
363 2408 809 -055
364 2432 817 -057
365 2457 826 -060
366 2481 835 -062
367 2506 843 -065
368 2530 852 -067
369 2555 861 -070
370 2579 870 -072
371 2604 879 -075
372 2628 888 -077
373 2653 898 -080
37315 2657 907 -083
Table H3 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in liquid
state (37915-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37915 2966 1025 -100 502 6174 2432 -667
380 2991 1034 -102 503 6198 2444 -674
381 3020 1045 -105 504 6222 2456 -680
382 3048 1056 -108 505 6246 2468 -686
383 3077 1067 -112 506 6270 2480 -692
384 3105 1078 -115 507 6294 2492 -699
385 3134 1089 -118 508 6317 2504 -705
386 3162 1100 -121 509 6341 2516 -711
387 3191 1111 -124 510 6365 2528 -718
140
388 3219 1122 -127 511 6388 2541 -724
389 3247 1133 -130 512 6412 2553 -730
390 3275 1144 -134 513 6436 2565 -737
391 3304 1155 -137 514 6459 2577 -743
392 3332 1166 -140 515 6483 2589 -750
393 3360 1177 -144 516 6506 2601 -756
394 3388 1188 -147 517 6530 2613 -763
395 3416 1199 -150 518 6553 2625 -769
396 3444 1210 -154 519 6577 2638 -776
397 3472 1221 -157 520 6600 2650 -782
398 3500 1232 -161 521 6624 2662 -789
399 3527 1243 -164 522 6647 2674 -796
400 3555 1254 -168 523 6670 2686 -802
401 3583 1265 -171 524 6694 2698 -809
402 3611 1276 -175 525 6717 2711 -816
403 3638 1287 -179 526 6740 2723 -822
404 3666 1299 -182 527 6763 2735 -829
405 3693 1310 -186 528 6786 2747 -836
406 3721 1321 -190 529 6810 2760 -843
407 3748 1332 -193 530 6833 2772 -850
408 3776 1343 -197 531 6856 2784 -856
409 3803 1354 -201 532 6879 2796 -863
410 3830 1366 -205 533 6902 2809 -870
411 3857 1377 -209 534 6925 2821 -877
412 3885 1388 -213 535 6948 2833 -884
413 3912 1399 -216 536 6971 2845 -891
414 3939 1410 -220 537 6994 2858 -898
415 3966 1422 -224 538 7017 2870 -905
416 3993 1433 -228 539 7040 2882 -912
417 4020 1444 -232 540 7063 2895 -919
418 4047 1455 -236 541 7086 2907 -926
419 4074 1467 -240 542 7108 2919 -933
420 4101 1478 -245 543 7131 2932 -940
421 4128 1489 -249 544 7154 2944 -947
422 4154 1500 -253 545 7177 2957 -955
423 4181 1512 -257 546 7199 2969 -962
424 4208 1523 -261 547 7222 2981 -969
425 4234 1534 -265 548 7245 2994 -976
426 4261 1546 -270 549 7267 3006 -984
427 4288 1557 -274 550 7290 3019 -991
141
428 4314 1568 -278 551 7313 3031 -998
429 4341 1580 -282 552 7335 3044 -1005
430 4367 1591 -287 553 7358 3056 -1013
431 4393 1602 -291 554 7380 3068 -1020
432 4420 1614 -296 555 7403 3081 -1028
433 4446 1625 -300 556 7425 3093 -1035
434 4472 1636 -305 557 7448 3106 -1042
435 4499 1648 -309 558 7470 3118 -1050
436 4525 1659 -314 559 7492 3131 -1057
437 4551 1671 -318 560 7515 3143 -1065
438 4577 1682 -323 561 7537 3156 -1072
439 4603 1694 -327 562 7560 3169 -1080
440 4629 1705 -332 563 7582 3181 -1087
441 4655 1716 -336 564 7604 3194 -1095
442 4681 1728 -341 565 7626 3206 -1103
443 4707 1739 -346 566 7649 3219 -1110
444 4733 1751 -351 567 7671 3231 -1118
445 4759 1762 -355 568 7693 3244 -1126
446 4785 1774 -360 569 7715 3257 -1133
447 4810 1785 -365 570 7737 3269 -1141
448 4836 1797 -370 571 7759 3282 -1149
449 4862 1808 -375 572 7782 3294 -1157
450 4888 1820 -379 573 7804 3307 -1164
451 4913 1832 -384 574 7826 3320 -1172
452 4939 1843 -389 575 7848 3332 -1180
453 4964 1855 -394 576 7870 3345 -1188
454 4990 1866 -399 577 7892 3358 -1196
455 5015 1878 -404 578 7914 3370 -1204
456 5041 1889 -409 579 7936 3383 -1212
457 5066 1901 -414 580 7957 3396 -1220
458 5092 1913 -419 581 7979 3408 -1228
459 5117 1924 -424 582 8001 3421 -1236
460 5142 1936 -430 583 8023 3434 -1244
461 5167 1947 -435 584 8045 3447 -1252
462 5193 1959 -440 585 8067 3459 -1260
463 5218 1971 -445 586 8088 3472 -1268
464 5243 1982 -450 587 8110 3485 -1276
465 5268 1994 -456 588 8132 3498 -1284
466 5293 2006 -461 589 8154 3510 -1292
467 5318 2017 -466 590 8175 3523 -1300
142
468 5343 2029 -472 591 8197 3536 -1308
469 5368 2041 -477 592 8219 3549 -1317
470 5393 2053 -482 593 8240 3562 -1325
471 5418 2064 -488 594 8262 3574 -1333
472 5443 2076 -493 595 8283 3587 -1341
473 5468 2088 -499 596 8305 3600 -1350
474 5493 2100 -504 597 8327 3613 -1358
475 5517 2111 -510 598 8348 3626 -1366
476 5542 2123 -515 599 8370 3639 -1375
477 5567 2135 -521 600 8391 3652 -1383
478 5592 2147 -526 601 8413 3664 -1391
479 5616 2158 -532 602 8434 3677 -1400
480 5641 2170 -537 603 8455 3690 -1408
481 5665 2182 -543 604 8477 3703 -1417
482 5690 2194 -549 605 8498 3716 -1425
483 5715 2206 -554 606 8520 3729 -1434
484 5739 2218 -560 607 8541 3742 -1442
485 5763 2229 -566 608 8562 3755 -1451
486 5788 2241 -572 609 8583 3768 -1459
487 5812 2253 -578 610 8605 3781 -1468
488 5837 2265 -583 611 8626 3794 -1477
489 5861 2277 -589 612 8647 3807 -1485
490 5885 2289 -595 613 8668 3820 -1494
491 5910 2301 -601 614 8690 3833 -1503
492 5934 2313 -607 615 8711 3846 -1511
493 5958 2324 -613 616 8732 3859 -1520
494 5982 2336 -619 617 8753 3872 -1529
495 6006 2348 -625 618 8774 3885 -1538
496 6030 2360 -631 619 8795 3898 -1546
497 6055 2372 -637 620 8816 3911 -1555
498 6079 2384 -643 621 8837 3924 -1564
499 6103 2396 -649 622 8858 3937 -1573
500 6127 2408 -655 623 8879 3950 -1582
501 6151 2420 -661 62315 8883 3952 -1583
143
Appendix I
Table I1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in solid state (29815-35315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 1171 366 -017
299 035 010 000 328 1211 379 -018
300 076 023 000 329 1250 392 -019
301 117 035 000 330 1290 405 -021
302 158 048 000 331 1330 418 -022
303 199 060 000 332 1369 431 -023
304 240 072 -001 333 1409 444 -025
305 281 085 -001 334 1448 458 -026
306 322 097 -001 335 1488 471 -028
307 363 110 -002 336 1527 484 -029
308 404 122 -002 337 1566 497 -031
309 445 135 -002 338 1605 510 -032
310 486 148 -003 339 1644 524 -034
311 526 160 -003 340 1683 537 -036
312 567 173 -004 341 1722 550 -037
313 608 186 -005 342 1761 563 -039
314 648 198 -005 343 1800 577 -041
315 689 211 -006 344 1839 590 -043
316 729 224 -007 345 1877 603 -044
317 770 237 -007 346 1916 617 -046
318 810 250 -008 347 1955 630 -048
319 850 262 -009 348 1993 643 -050
320 891 275 -010 349 2031 657 -052
321 931 288 -011 350 2070 670 -054
322 971 301 -012 351 2108 683 -056
323 1011 314 -013 352 2146 697 -059
324 1051 327 -014 353 2184 710 -061
325 1091 340 -015 35315 2190 712 -061
326 1131 353 -016
144
Table I2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in liquid state (39115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
39115 4413 1056 -191 508 8890 3521 -978
392 4450 1535 -195 509 8924 3538 -986
393 4492 1549 -200 510 8959 3556 -995
394 4535 1566 -204 511 8993 3574 -1004
395 4577 1583 -209 512 9027 3591 -1013
396 4620 1599 -213 513 9062 3609 -1022
397 4662 1616 -218 514 9096 3626 -1031
398 4704 1633 -223 515 9130 3644 -1041
399 4746 1650 -227 516 9164 3661 -1050
400 4789 1666 -232 517 9198 3679 -1059
401 4831 1683 -237 518 9232 3697 -1068
402 4872 1700 -242 519 9266 3714 -1077
403 4914 1717 -247 520 9300 3732 -1087
404 4956 1734 -252 521 9334 3750 -1096
405 4997 1751 -257 522 9368 3767 -1105
406 5039 1767 -262 523 9402 3785 -1115
407 5080 1784 -267 524 9435 3802 -1124
408 5122 1801 -272 525 9469 3820 -1134
409 5163 1818 -277 526 9503 3838 -1143
410 5204 1835 -282 527 9536 3855 -1152
411 5245 1852 -287 528 9570 3873 -1162
412 5286 1869 -293 529 9603 3891 -1172
413 5327 1885 -298 530 9637 3908 -1181
414 5368 1902 -303 531 9670 3926 -1191
415 5409 1919 -309 532 9703 3944 -1201
416 5450 1936 -314 533 9737 3962 -1210
417 5490 1953 -320 534 9770 3979 -1220
418 5531 1970 -325 535 9803 3997 -1230
419 5571 1987 -331 536 9836 4015 -1240
420 5612 2004 -336 537 9869 4032 -1249
421 5652 2021 -342 538 9902 4050 -1259
145
422 5692 2038 -347 539 9935 4068 -1269
423 5732 2055 -353 540 9968 4086 -1279
424 5772 2072 -359 541 10001 4104 -1289
425 5812 2089 -365 542 10034 4121 -1299
426 5852 2106 -371 543 10066 4139 -1309
427 5892 2123 -376 544 10099 4157 -1319
428 5932 2140 -382 545 10132 4175 -1329
429 5971 2157 -388 546 10165 4192 -1340
430 6011 2174 -394 547 10197 4210 -1350
431 6051 2191 -400 548 10230 4228 -1360
432 6090 2208 -406 549 10262 4246 -1370
433 6129 2225 -412 550 10295 4264 -1380
434 6169 2242 -419 551 10327 4282 -1391
435 6208 2259 -425 552 10359 4299 -1401
436 6247 2276 -431 553 10392 4317 -1411
437 6286 2293 -437 554 10424 4335 -1422
438 6325 2310 -444 555 10456 4353 -1432
439 6364 2327 -450 556 10488 4371 -1443
440 6403 2344 -456 557 10520 4389 -1453
441 6442 2361 -463 558 10553 4407 -1464
442 6480 2378 -469 559 10585 4424 -1474
443 6519 2395 -476 560 10617 4442 -1485
444 6557 2412 -482 561 10648 4460 -1496
445 6596 2429 -489 562 10680 4478 -1506
446 6634 2446 -495 563 10712 4496 -1517
447 6673 2464 -502 564 10744 4514 -1528
448 6711 2481 -509 565 10776 4532 -1538
449 6749 2498 -515 566 10808 4550 -1549
450 6787 2515 -522 567 10839 4568 -1560
451 6825 2532 -529 568 10871 4586 -1571
452 6863 2549 -536 569 10902 4604 -1582
453 6901 2566 -543 570 10934 4622 -1593
454 6939 2584 -550 571 10965 4640 -1604
455 6977 2601 -557 572 10997 4658 -1615
456 7015 2618 -564 573 11028 4676 -1626
457 7052 2635 -571 574 11060 4694 -1637
458 7090 2652 -578 575 11091 4712 -1648
459 7128 2670 -585 576 11122 4730 -1659
460 7165 2687 -592 577 11154 4748 -1670
461 7202 2704 -599 578 11185 4766 -1681
146
462 7240 2721 -606 579 11216 4784 -1692
463 7277 2738 -614 580 11247 4802 -1704
464 7314 2756 -621 581 11278 4820 -1715
465 7351 2773 -628 582 11309 4838 -1726
466 7388 2790 -636 583 11340 4856 -1737
467 7425 2807 -643 584 11371 4874 -1749
468 7462 2825 -650 585 11402 4892 -1760
469 7499 2842 -658 586 11433 4910 -1772
470 7536 2859 -665 587 11464 4928 -1783
471 7573 2877 -673 588 11495 4946 -1794
472 7609 2894 -680 589 11525 4964 -1806
473 7646 2911 -688 590 11556 4982 -1817
474 7682 2928 -696 591 11587 5001 -1829
475 7719 2946 -703 592 11617 5019 -1841
476 7755 2963 -711 593 11648 5037 -1852
477 7792 2980 -719 594 11678 5055 -1864
478 7828 2998 -727 595 11709 5073 -1876
479 7864 3015 -735 596 11739 5091 -1887
480 7900 3032 -742 597 11770 5109 -1899
481 7937 3050 -750 598 11800 5128 -1911
482 7973 3067 -758 599 11831 5146 -1923
483 8009 3084 -766 600 11861 5164 -1935
484 8045 3102 -774 601 11891 5182 -1946
485 8080 3119 -782 602 11921 5200 -1958
486 8116 3137 -791 603 11952 5218 -1970
487 8152 3154 -799 604 11982 5237 -1982
488 8188 3171 -807 605 12012 5255 -1994
489 8223 3189 -815 606 12042 5273 -2006
490 8259 3206 -823 607 12072 5291 -2018
491 8294 3224 -832 608 12102 5309 -2030
492 8330 3241 -840 609 12132 5328 -2042
493 8365 3259 -848 610 12162 5346 -2055
494 8401 3276 -857 611 12192 5364 -2067
495 8436 3293 -865 612 12222 5382 -2079
496 8471 3311 -873 613 12252 5401 -2091
497 8506 3328 -882 614 12281 5419 -2103
498 8542 3346 -890 615 12311 5437 -2116
499 8577 3363 -899 616 12341 5456 -2128
500 8612 3381 -908 617 12370 5474 -2140
501 8647 3398 -916 618 12400 5492 -2153
147
502 8681 3416 -925 619 12430 5510 -2165
503 8716 3433 -934 620 12459 5529 -2178
504 8751 3451 -942 621 12489 5547 -2190
505 8786 3468 -951 622 12518 5565 -2203
506 8820 3486 -960 623 12548 5584 -2215
507 8855 3503 -969 62315 12552 5602 -2217
x
LIST OF FIGURES
11 Theoretical and engineering energy conversion efficiency as function of temperature 6
12 Gravimetric storage density for different energy storage systems
as function of temperature 8
51 Photography of set-up for DSC equipment 31
61 Melting point calibration with indium sample 34
62 Melting point calibration with KNO3 sample 35
63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt 36
64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt 37
65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt 37
66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt 38
67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt 38
68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt 39
69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt 39
610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt 40
611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN Salt 40
612 DSC plot of 698wt KNO3 -302wt NaNO2 binary system 43
xi
613 DSC plot of 270wt NaNO3-730wt KNO3 binary system 45
614 DSC plot of 458wtLiNO3-542wtKNO3 binary system 45
615 DSC plot of 460wt NaNO3-540wt KNO3 binary system 46
616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 20oCmin heating rate 47
616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
for 5oCmin heating rate 48
617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 5oCmin heating rate 49
617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
for 20oCmin heating rate 49
618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system
as function of temperature 53
619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K 54
620 Change of Gibbs energy as function of temperature for molten salt systems 85
621 The densities of the salt 1 to salt 5 as function of temperature 87
622 The densities of the salt 6 to salt 9 as function of temperature 89
623 Densities of the salt 1 salt 2 as function of temperature compared to
the equimolar NaNO3-KNO3 binary system and pure KNO3 90
624 Gravimetric storage density comparison of different energy storage
xii
systems as function of temperature 93
1
CHAPTER 1
INTRODUCTION
Renewable energy sources such as wind solar water power geothermal and biomass are
playing more and more significant role in our energy supply Because the cheap cost and infinite
amount of energy storage inside the resource solar energy is emphasized since 20th
century and
viewed as promising alternative method to satisfy the large energy consumption every day in the
world reduce the emission of carbon and strengthen the economy
The wind energy was used as a clean energy to generate electricity back to late 19th
century
However this renewable energy source was not emphasized due to the cheap price of fossil fuel
The re-emergence happened in mid 1950s when the amount of traditional energy source was
found apparently decrease The development of wind energy usage continued and in 1990 the
first mega-watt wind turbine was launched which was viewed as a symbol of shift to large scale
wind energy utilization [1-2] The modern application of wind energy mainly relies on wind
turbine On the basis of aerodynamic wind turbine generates certain net positive torque on
rotating shaft and then converts the mechanical power to electrical power As an electrical power
generator wind turbine is connected to some electrical network to transport the electricity to
battery charging utilities residential power systems and large scale energy consuming systems
In general most of wind turbines are small scale and can only generate 10KW electrical power
Only few of the wind turbine systems operate with capacity as large as 5MW Although the
usage of wind energy can reduce the emission of carbon oxide the noise pollution and high cost
2
limit its large scale application Since the wind is not transportable the electrical energy can only
be generated where the wind blows which also decrease the flexibility of wind energy
Water power is another term of alternative power supply and it was used for irrigation
operating machines like watermill even before the development of electrical power The modern
application of water power is to generate electricity by using the gravitational force of falling or
flowing water These days there are various ways for the water power application The most
traditional method is to store the water in dam and generate electricity by converting the
potential energy pump storage is a different way to utilize water power and can change its
output depending on the energy demand by moving water between reservoirs at different
elevations In the low energy demand period excess energy is used to lift water to the higher
level while in the peak period of energy demand the water is released back to the lower
elevation through water turbine Water power can also be converted by taking advantage of
naturally raise and fall of tide to satisfy the demand of electrical energy consumption [3]
Although the usage of water power can reduce the emission of carbon dioxide and cost it will
destroy the ecosystem because of the large land required for construction There will be methane
emission from the reservoir the potential failure hazard of dam is also a fatal issue and flow
shortage caused by drought may also create serious problem As result of that water power
technique is not a long-term alternative choice
Geothermal energy is the energy form generated inside the earth At the very beginning of
the planet formation a large amount of thermal energy was stored from the radioactive decay of
minerals volcanic activity and solar energy absorption Because of the temperature difference
3
between the core and the surface of planet the thermal energy stored inside the earth is driven to
the outer surface in the form of heat This form of renewable energy source can be applied to
generate electrical power and heat for industrial space and agricultural applications
Theoretically the deposited amount of geothermal energy is adequate to supply the energy
consumption in the world However most of the geothermal energy is stored deeply near the
core of the earth the deep drilling and exploration of geothermal energy is very expensive and
limits the large-scale use of this renewable energy source [4]
Biomass is a renewable energy source used to generate heat or electricity with living or
recently living organism such as wood waste (hydrogen) gas and alcohol fuels The biomass
energy can be converted to electrical energy by thermal method such as combustion pyrolysis
and gasification Several specific chemical processes may also be able to convert the biomass
energy to other forms The main problem arise from application of biomass is air pollution which
contains carbon monoxide NOx (nitrogen oxides) VOCs (volatile organic compounds)
particulates and other pollutants And the level of air pollution to some extent is even above that
of traditional fuel resource Some other possible issue like transportation and sink of carbon also
limit the wide usage of this type of alternative energy [5]
Among all the renewable energy sources solar energy is the most suitable alternative
energy for our future life It is clean cheap abundant without any noise air pollution no
transportation issue and easy to be obtained anywhere in the earth Inside the core of the Sun
hydrogen fuses into helium with a rate of 7times1011
kgs and generates very powerful nucleation
power This type of nucleation explosion creates ultra high temperature in the core of the Sun
4
which reaches approximately 16 million K degrees Although the Sun is not perfectly black body
it still radiates abundant power with the energy density as 16times107 wattsm
2 [6-7] Because of the
enough amount of hydrogen underneath the surface of the Sun the radiation given arise of from
the nucleation explosion can continue at least 5 million years with the same rate and strength
The energy reaching the earth is vastly reduced mainly caused by the absorption and spreading
of the radiation It is easily to understand that there are numerous amorphous objects all around
the entire universe which can absorb certain portion of the radiation for the Sun Moreover the
light generated from the spherical object such as the Sun fills all the available space between the
origin to the destination Even though the energy will not be lost in the travelling process due to
the long distance between the Sun to the earth the surface area of the sphere which is formed
with the Sun as center and the distance as radius is much larger than that of the earth As the
result of that only 1340Wm2 finally reaches the upmost surface of the earth Even though the
final amount of the received solar energy is very small compared to that is initially radiated from
the Sun the average daily solar radiation falling on one area in the continental United States is
equivalent in total energy content to 11 barrels of oil In summary the solar energy itself is
relatively unlimited useful clean and almost unexploited energy and definitely can behave as
the promising mean for the future energy supply [8]
There are several different methods to take advantage of the solar energy and all the
methods can be distinguished into three group solar parabolic trough solar tower and solar dish
Parabolic trough is constructed by silver coated parabolic mirror and there is a Dewar tube going
through the length of the mirror and set on the focal point all the radiation is concentrated on the
tube and transfer by heat transfer fluid to the thermal energy storage unit Solar tower are used to
5
capture solar energy with thousands of mirrors and focus the concentrated sunlight to the top of
the tower which is located in the middle of the heliostats The thermal energy storage medium
within the tower was heated to high temperature and transferred to thermal energy storage tank
and eventually sent to steam pump The solar dish is built with a large reflective parabolic dish
which concentrates all the received sunlight to one spot There is normally a receiver located on
the focal point and transform the solar energy to other forms of useful energy The working
upper limit temperature of solar parabolic trough system is the lowest among these three systems
normally its maximum working temperature is within the range from 400-500oC the solar tower
has higher maximum working temperature which ranges from 500-1000oC the solar dish has the
highest working upper limit temperature which reaches 700-1200oC [9]
The energy conversion efficiency is the most concerned parameter in the solar energy
storage application and the theoretical and real engineering efficiency are given in fig 11 as
function of temperature The theoretical conversion efficiency can be up to 80 while in real
application the value is always less than 70 regardless of collectors The actual efficiency
increases with temperature in the whole working temperature As a result of that the thermal
energy storage materials in solar parabolic trough for instance should be able to work stably at
the upper limit temperature of this type of collection system which is 500oC to ensure the highest
efficiency [9 10]
6
Fig 11 Theoretical and engineering energy conversion efficiency as function of
temperature
Solar energy can be stored in three major forms sensible heat latent heat and
thermochemical heat Sensible heat storage was utilized based on the heat capacity and the
change as function of temperature of storage materials in the charging and discharging process
which correspond to the absorbing and withdrawing energy processes respectively The sensible
heat stored from the melting point to the maximum working temperature can be expressed by
equation 1 [9]
[1]
Where m is the mass of storage material Tmp and TH are melting point temperature and high
temperature in the same phase respectively Cp(T) is the heat capacity at different temperature
Because the sensible heat storage materials remain in a single phase in the working temperature
range the charging and discharging processes are completely reversible for unlimited cycles
7
Latent heat storage is operated by absorbing and withdrawing energy in the charging and
discharging processes accompanied with fusion of materials [9] The latent heat collected
throughout the working temperature range can be expressed by equation 2 as following
[2]
Where T is temperature in solid state Tmp is melting point temperature of storage material TH is
the high temperature in liquid state and is enthalpy of fusion
Thermochemical heat storage is based on the heat capacity and its change as function of
temperature accompanied with chemical reaction The thermochemical heat collected throughout
the working temperature range can be expressed by equation 3
[3]
Where TL is the low temperature before the reaction TR is the reaction temperature and
is the enthalpy of chemical reaction Because of the destruction of the chemical bonds
in the reaction process the charging and discharging process cannot be completely reversible
which reduces the stability and recyclability of storage operation [10]
Sensible energy storage method is chosen to ensure the efficient usage of solar energy for
parabolic trough system of which the maximum working temperature ranges from 400-500oC
Different from thermochemical heat storage the sensible heat storage can achieve completely
reversible working condition under unlimited cycles Also fig 12 illustrates that the sensible
heat storage materials mainly work in the working temperature range for parabolic trough system
8
and the gravimetric energy storage densities of sensible heat is higher than that of latent heat
materials [9 -11]
Fig 12 Gravimetric storage density for different energy storage systems as function of
temperature
Various materials are chosen to serve as thermal energy storage fluid for sensible heat
such as water thermal oil ionic liquid and molten salt [12] The properties of different heat
transfer fluid determine the performance of solar energy heating system In these days the
efficiency and cost of output of electrical power mainly relies on the parabolic trough solar
power plant and the thermal storage fluid [12] A large investment cost is needed to dispatch
100MW to 200MW energy by consuming the energy transfer fluids Given by this situation the
development of new thermal storage fluid with higher thermal energy storage density is
paramount to lower the expense for generating energy and a lot of effect has been put on design
of new systems [13-16]
9
Water is commonly used as heat transfer and thermal energy storage fluid in industry
because of its low cost high heat capacity and high thermal conductivity However the
limitation for using this medium is also obvious that the temperature range within which the
liquid state can be assured is too small It is well know that water can only serve as thermal
energy storage liquid above the freezing point 0oC and below the boiling temperature 100
oC In
practical experiment the actual temperature range is even less than 100oC because of the large
amount of weight loss near the boiling temperature due to the high vapor pressure Water is
possible to work above 100oC only if high pressure is also applied to avoid the phase
transformation but the cost will be highly increased Accordingly water is only suitable to work
in low temperature below 100oC
Thermal oils are also being used in the parabolic trough solar power plant and have very
low melting point as low as 12oC [17 18] However the application of the oil for the thermal
energy storage liquid is limited by some disadvantages from the physic-chemical properties The
upper limit for this oil is only 300oC and above that the liquid state cannot be maintained
Moreover the low thermal decomposition temperature low density and low heat capacity result
in limited thermal energy storage capacity Since the working temperature range is so narrow the
rankie cycle efficiency is reduced when using the synthetic oil and the cost for generating power
is considered to be very expensive [19 20]
Ionic liquid is another medium served as thermal energy storage fluid The liquid
temperature range of ionic liquid is large which is one of the main advantages of this type of
material The high heat capacity and density ensure the efficiency of thermal energy storage of
10
ionic liquid What‟s more the excellent chemical stability and little vapor pressure increase the
lifetime [21-24] However as a result of the very serve corrosion problem to the liquid container
and the high cost the usage of ionic liquid is still limited
Considering various relative physic-chemical properties of thermal energy storage system
molten salts have been proposed as a suitable group for a wide temperature range application
They are being emphasized in the solar energy applications because of their low melting point
and high upper limit which can increase the stable working range The high heat capacity
increases the thermal energy storage density of the heat storage system excellent thermal
stability and negligible vapor pressure ensure the steadiness of cyclic repeating in the lifetime
[25] low viscosity strengths the mobility and efficiency of the thermal storage liquid low
utilization cost reduce the investment and protect the economy The liquidus temperature range
of the molten salt varies from 150-600oC combination of various salts can bring the melting
down and further increase the working temperature range Due to these properties molten salts
can be excellent thermal energy storage fluid in the solar power generation system
11
CHAPTER 2
LITERATURE REVIEW
Several physical and thermodynamic properties of thermal energy storage fluid play
significant role in determining the efficiency and performance of solar energy storage systems In
order to evaluate the feasibility of systems the physic-chemical properties of several molten salts
should be reviewed The three determining parameter which directly affect the thermal energy
storage capacity in systems are melting point heat capacity and density
There are large amount of melting point data available in the literature for various molten
salt system in previous literatures while those with melting point less than 120oC is very limited
All the previous study on molten salt system revealed that five group of molten salts are
emphasized and commonly used alkai or alkaline nitrates carbonates sulphates chloride and
hydroxides Although most of the systems have the same group of cation the melting point
varies a lot from one to anther due to the different effect of anions
21 Melting point
The melting points of individual and multi-component nitratenitrite systems are listed in
Table 21[26-31] Among those systems solar salt (NaNO3KNO3 6040) is the thermal energy
storage medium which is currently being used with the freezing point of 221oC [27] Although
the melting point for this system is highest in all the candidate mixtures in this group the lowest
12
combined compound cost makes it widely used in solar energy storage field Another ternary
system HITEC which contains NaNO3 KNO3 and NaNO2 has freezing point of 141 oC [28]
This combination brings the melting point down but the lack of combination of optimum features
limits its further application [29] Some mixtures such as LiNO3-Ca(NO3)2-KNO3 are not often
utilized because they increase the compound cost at the same time of lowering the melting point
to around 120oC [30] moreover the decreased melting point is still high compared to the
organic oil There are also several systems have the melting points less than 100oC or even 60
oC
they are not used in the parabolic trough solar power plant due to the decomposition of some
components during high temperature [31]
Table 21 Melting point of various nitrate salt systems
Compound Melting Point (ordmC)
LiNO3 253
NaNO3 307
KNO3 334
Ca(NO3)2 561
Sr(NO3)2 570
Ba(NO3)2 590
NaNO3-NaNO2 221
NaNO3-NaNO2-KNO3 141
NaNO3-KNO3-CaNO3 133
LiNO3-KNO3-NaNO3 120
KNO3-CaNO3-LiNO3 117
LiNO3-KNO3-NHNO3 92
KNO3-NHNO3-AgNO3 52
The melting points of individual and multi-component carbonate systems are listed in
Table 22 [26 32 33] Different from the nitrate salts the melting points for both the individual
13
and multi-component carbonate systems are on the higher side The lowest melting point is
achieved with lithium sodium and potassium carbonate ternary system whose melting point is
still 277oC higher than that of the nitrate ternary system with the same cations [32] Besides
because of the thermal decomposition issue the choice of component involved in the multi-
component carbonate systems is limited Some salt like CaCO3 doesn‟t have stable form at high
temperature and the lack of multi-component system reduces the chance of the synthesis of low
melting point salt mixtures Even though this group of salt is not thermally stable and the
working temperature range is relatively small it is still viewed as possible candidate working at
high temperature due to its low price
Table 22 Melting point of various carbonate salt systems
Compound Melting Point (ordmC)
Li2CO3 732
Na2CO3 858
K2CO3 900
MgCO3 990
Na2CO3-K2CO3 710
Li2CO3-Na2CO3 496
Li2CO3-K2CO3 488
Li2CO3-K2CO3-Na2CO3 397
Alkali and Alkaline fluoridechloride salts are also selected as one possible choice as the
thermal energy storage fluid and the melting point examined from previous literatures are given
in table 23 [34-38] A lot of study has been done for this group of salt and the melting points
were found in the same range as the carbonate group And for the pure salt metal chloride salts
have lower melting point than metal fluoride ones
14
Table 23 Melting point of various fluoridechloride salt systems
Compound Melting Point (ordmC)
LiF 849
NaF 996
KF 858
LiCl 610
NaCl 801
KCl 771
LiF-KF 493
LiF-NaF 652
LiCl-KF 487
LiF-NaF-KF 454
LiF-NaF-KF-MgF2 449
LiF-KF-BaF2 320
LiF-KF-CsF-RbF 256
Several studies were also conducted to determine the melting point of molten hydroxide
salts and the results are shown in Table24 The data of pure salts and multi-component mixtures
merely in this group were not much determined in the literatures Generally they are mixed with
other groups of anion and form some low melting point salt mixtures [39-42] On the basis of the
previous literature data alkali hydroxide salts and their mixture with salts in other groups have
relatively lower melting point compared with pure carbonate and fluoride chloride group salt
mixtures Most of the melting points given in Table 4 are lower than 300oC sodium potassium
hydroxide binary mixture even reaches the melting point below 200oC Accordingly relatively
large temperature range can be obtained by using hydroxide salt mixtures or adding them as
additive
15
Table 24 Melting point of various hydroixde salt systems
Compound Melting Point (ordmC)
LiOH-LiF 427
NaOH-KOH 170
LiOH-NaOH 213
NaOH-NaNO2 232
NaOH-NaNO3 237
NaOH-NaCl-NaNO3 242
NaOH-NaCl-Na2CO3 282
22 Density
For the solar energy storage system density for the thermal energy storage fluid is also
essential parameter The density is needed for the size calculation as function of temperature and
assessing for the thermal stability of thermoclines Besides density as function of temperature is
used to evaluate the volume change in the process of freezing which contributes to potential
stress
Alkalialkaline nitrate salts were studied very much about their density as function of
temperature All the results indicate that the density was decreased linearly as temperature
increases and any specific density value in the molten state can be expressed by equation as
equation 4
= A-BT [4]
Where (gcm3) is the density of salt A (gcm
3) is the initial density value at 0
oC and B
(mgcm3degC) is the density change slope as function of temperature The coefficients are shown in
16
Table 25 for the nitrate group molten salts Among these systems pure sodium nitrate has the
largest value which reveals the high initial density value at low temperature [43] Conversely
lithium nitrate has the lowest value while it presents the smallest decrease trend as temperature
increases [44] The densities and A B values of multi-component nitrate salts were included in
the range of those two salts discussed above
Table 25 Density coefficients A and B of nitrate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiNO3 1922 0556
NaNO3 2334 0767
KNO3 2127 0760
NaNO3-KNO3 2134 0773
KNO3-CaNO3-LiNO3 2172 0735
LiNO3-KNO3-NaNO3 2083 0715
Several experiments were also conducted to measure the density as function of temperature
for the individual and multi-component carbonate salt systems The density of the carbonate salt
also follow the same trend as that of nitrate salt and the temperature dependence of density
followed the linear equation as discussed above It is observed that all the carbonate salts have
higher initial density coefficient A than the nitrate salt The largest value is reached to 2511 and
even the lowest value in this group is greater than the maximum A of nitrate group [45-49]
What‟s more the regression slope coefficient B of carbonate salt is lower compared to that of the
nitrate salt group Accordingly the salts in this group present larger density in the molten state
and the density coefficient A and B are given in Table 26
17
Table 26 Density coefficients A and B of carbonate salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
Li2CO3 2303 0532
Na2CO3 2350 0448
Na2CO3-K2CO3 2473 0483
Li2CO3-K2CO3 2511 0599
Li2CO3-Na2CO3 2456 0519
Li2CO3-Na2CO3-K2CO3 2364 0544
Density of metal fluoride and chloride molten salt were also examined and present similar
regression trend as temperature increases The linear temperature dependence is also expressed
by the same equation On the basis of previous literature data the pure chloride salt shows lower
density than the fluoride salt with the same cation in the molten state [49] What‟s more the
sodium halide salt has the largest density value while the lithium halide salt has the lowest value
which is very similar to the nitrate group salt The density determination coefficient A and B are
given in Table27
Table 27 Density coefficients A and B of chloridefluoride salts
Compound A(gcm3) Btimes103(gcm
3degC)
LiCl 1766 0432
NaCl 1991 0543
KCl 1976 0583
LiF 2226 0490
NaF 2581 0636
KF 2469 0651
LiF-NaF 2520 0818
LiCl-NaF-KCl 2436 0742
LiF-NaF-MgF 2240 0701
18
The density measurement of hydroxide was not conducted as much as those three anion
groups discussed above Only few data of density is available for the alkali hydroxide salt when
added into other salt systems and temperature dependence also follows the linear regression
trend [32 41] The density determination coefficient A and B are given in Table 28
Table 28 Density coefficients A and B of molten salt mixture with hydroxide salts
Compound A(gcm3) Btimes10
3(gcm
3degC)
LiCl-LiOH 16 0443
LiF-LiOH 165 0471
23 Heat capacity
In the heating process the temperature of solar energy storage molten salt is increase by
absorbing energy from the solar radiation Conversely the same amount of heat is released and
applied to heating system in the process of cooling Heat capacity is the amount of heat required
to increase the temperature of certain material by 1 oC and can be viewed as the directly relevant
parameter to the energy storage ability To some extent the large heat capacity assures the
efficiency of the application of solar energy storage materials
The heat capacity of alkalialkaline nitrate salt was investigated for both individual and
multi-component system in the previous literature To simplify the comparison only the heat
capacity value at 500oC is shown in all the following tables In the liquid state the heat capacity
increases with temperature following linear equation and the increasing slope is as small as 10-5
to 10-4
[50 51] Among those alkali nitrate salt systems lithium nitrate has the largest heat
19
capacity at 500oC while potassium nitrate presents the lowest value at that temperature In table
29 the heat capacity results at the selected temperature in literature are given
Table 29 Heat capacity of alkali nitrate salt at 500oC
Compound Heat capacity(JgK)
LiNO3 2175
NaNO3 1686
KNO3 1400
NaNO3-KNO3 1533
LiNO3-KNO3 1642
LiNO3-KNO3-NaNO3 1681
For the carbonate salt systems in the molten state the heat capacity is almost constant and
almost independent with temperature [32 33] Same as the nitrate group salts the heat capacity
for pure carbonate salt decreases as the atomic number of the alkali element increases which
means the value for lithium carbonate is the largest and that of potassium carbonate is the
smallest Generally the heat capacity value for carbonate in molten state is larger than that in
solid state However the sodium-potassium carbonate binary system is an exception for which
the heat capacity in solid state is larger than liquid state In table 210 the heat capacity results of
carbonate salts at the selected temperature in literature are given
Table 210 Heat capacity of alkali carbonate salt at 500oC
Compound Heat Capacity(JgK)
Li2CO3 250
Na2CO3 178
K2CO3 151
Na2CO3-K2CO3 157
20
Li2CO3-K2CO3 160
Li2CO3-Na2CO3 209
Li2CO3-K2CO3-Na2CO3 163
The heat capacity of fluoridechloride salt was measured in several literature and found
that for the pure salt the lithium halide has the biggest heat capacity data in the molten state
while the potassium halides shows the lowest heat capacity value Similar to the carbonate group
the heat capacity value of fluoridechloride salt varies little with temperature in the liquid state
[32 33] The values at 500oC for the alkalialkaline halides are shown in Table 211
Table 211 Heat capacity of fluoridechloride salt at 500oC
Compound Heat Capacity (JgK)
LiCl 148
NaCl 115
KCl 090
LiF-KF 163
NaCl-MgCl2 100
LiF-NaF-KF 155
KCl-MgCl2-CaCl2 092
The heat capacity of pure and multi-component hydroxide salt systems is limited in the
previous literature and the values in the liquid state follow linear equation which is observed for
all the molten salt discussed above [52] The values at 500oC for the alkalialkaline halides are
shown in Table 212
21
Table 212 Heat capacity of hydroxide salt at 500oC
Compound Heat Capacity(JgK)
NaOH 188
LiOH-NaOH 221
NaOH-KOH 182
In summary on the basis of comparison of various physic-chemical properties molten
nitrate slats have relatively low melting point excellent working temperature range reasonable
density and high heat capacity As the result of that molten nitrate salt is suitable to be applied as
the thermal energy storage fluid in the solar energy storage system
22
CHAPTER 3
OBJECTIVES
Based on review of previous literature data it is found that there are several disadvantages
such as the high melting point relatively low density value or poor heat capacity in liquid state
which limit the application of molten salt in certain groups in solar thermal energy storage
system Conversely alkalialkaline nitrate salt is considered as the suitable choice and proposed
as the thermal energy storage liquid for high temperature
Currently the used thermal energy storage liquid is NaNO3 (60mol)-KNO3 (40mol)
binary system (solar salt) which has the melting point at 221oC [30] Although the melting point
for this salt mixture is not the lowest it is still emphasized because of its low investment cost
However there are some drawbacks for this binary nitrate mixture The main disadvantage is
the high melting point In evenings or in winter the molten salt can easily freeze and block the
pipeline As a result of that some auxiliary cost should be added to overcome this problem and
the total investment will be increased
Development and synthesis of newer molten salt mixtures with freezing point lower than
those currently used for thermal energy storage applications is necessary for higher efficiency of
utilization of solar energy and getting rid of any unnecessary cost The approach to develop
lower freezing point molten salt mixtures is by the prediction of new eutectic mixtures and also
23
by the development of new nitrate compounds Besides these two most well known systems
several other mixtures were also studied Preliminary evaluation of several new molten salt flux
systems based on requirements for thermal energy storage systems mainly including freezing
point density heat capacity viscosity and thermal energy storage density The promising
candidate low melting point molten salt system should satisfy the requirements that eutectic
melting temperatures are lower than 220oC and the thermal energy storage densities are higher
than binary solar salt It is known that the melting point can be lowered by the addition of one or
more ABNO3 nitrate compounds where A and B are cations Consequently several multi-
component systems which have more constituent salts than solar salt were came up with and
studied with little fundamental data on the physic-chemical properties at the required operating
conditions available at present
In this thesis the new systems with simulated eutectic compositions were tested for their
experimental melting points heat capacities using the Differential Scanning Calorimetry (DSC)
technique which is considered to be the accurate instrument for thermodynamic data analysis
[53-59] Some significant thermodynamic properties such as heat capacity enthalpy and entropy
and Gibbs energy were calculated in the thesis to evaluate the energy change of the system in the
phase change process and the potential of being applied in the parabolic trough solar power plant
The energy density was obtained by using the experimental measured density and heat capacity
of the mixtures in molten state Finally 9 down-selected systems were present and discussed
24
CHAPTER 4
THERMODYNAMIC MODELING OF SALT SYSTEMS
41 Thermodynamic modeling
To lower the melting point of solar energy storage system multi-component system is
applicable Thermodynamic model was introduced to predict the eutectic temperature of salt
systems based on the Gibbs energies of fusion of individual salt and that of mixing of constituent
binary systems At the eutectic temperature the Gibbs energies in the liquid state and solid state
of salt are equal In thermodynamics Gibbs energy of fusion can be expressed by the equation
given as follows
G = H-TS [5]
Where H is the change of enthalpy of fusion and S is the change of entropy of fusion Equally
the entropy change of fusion can be expressed by differentiating G and the equation is given
[6]
It is known that the change in entropy can be expressed in terms of change in heat capacity in the
melting process as
[7]
25
If the change of heat capacity is assume to be independent of temperature the integral of
from Tm to T can be shown as
[8]
where Sm is the entropy of fusion at the melting point which is equal to Accordingly
Eq8 can be rewritten as
[9]
Substituting Eq 9 in Eq 6 and integrating the equation from Tm to T we get
[10]
Eq 10 illustrates that by using the change of heat capacity melting point and enthalpy of fusion
the Gibbs energy change at any temperature can be obtained
The standard Gibbs energy of fusion of a salt bdquo1‟ can be expressed in terms of the activity
of the salt as
[11]
where is the molar excess Gibbs energy and X1 is the molefraction of the salt bdquo1‟ Gibbs
energy of fusion at any give temperature T is expressed by Eq 7 in terms of its molefraction and
partial molar excess Gibbs energy
26
Take LiNO3-NaNO3-KNO3 as an example in which the integral molar excess Gibbs energy is
composed of the summation of the Gibbs energies of three constituent binary system and one
ternary The expression of the integral excess Gibbs energy is given by Eq12
[12]
Gibbs energies of the three constituent binary systems LiNO3-NaNO3 LiNO3-KNO3 and
NaNO3-KNO3 of the LiNO3-NaNO3-KNO3 ternary system are taken from the literature [48 49]
The Gibbs energies of mixing or the integral excess Gibbs energies of the three constituent
binary systems of the LiNO3-NaNO3-KNO3 ternary system are given below
LiNO3-NaNO3 Binary System
Jmol [13]
LiNO3-KNO3 Binary System
Jmol [14]
NaNO3-KNO3 Binary System
Jmol [15]
When assume the intergral excess Gibbs energy of to be zero the excess Gibbs energy in
the ternary system can be expressed by the summation of three constituent binary systems
[16]
27
Generally the partial molar excess Gibbs energies are reduced from the integral molar
excess Gibbs energy and can be expressed by the generalized equation for certain ldquomrdquo
component salt as
[17]
In the ternary system the i value equals to 12 and 3 and the partial molar excess Gibbs energy
of mixing for each component can be expressed as follows
[18]
[19]
[20]
Based on Eq 7 and the partial molar excess Gibbs energy of individual component the
Gibbs energy in the fusion can be expressed as Eq21- 23
[21]
[22]
[23]
42 Calculations
The fusion of the ternary salt system is defined by solutions of Eq 21-Eq 23 Newton-
Raphson method can be used to solve these three non-linear equations by linearizing the non-
linear equations using the Taylor series and truncating the series to first order derivatives
28
Consider the three non-linear functions F G and H in three variables x y and z The three
equations that are solved for the three variables are written as
F(x y z) = 0
G(x y z) = 0
H(x y z) = 0 [24]
The partial derivatives of the function F with respect to x y and z are given as
[25]
Similarly the partials derivatives can be expressed for the other two functions G and H
Newton-Raphson iterative method of solving the three equations in three variables
essentially deals with the solution of the incremental vector in the matrix equation given below
[26]
For the initial values of x y and z (say xi yi and zi) the right hand side vector contains the
values of the functions at the initial values (xi yi and zi) The 3times3 matrix on the left hand side
contains the partial derivatives of the functions with respect to the three variables at the initial
values Solutions of the matrix equation (Eq 26) result in the increments of the variables x y
and z The variables for the next iteration will then be xi + x yi + y and zi + z The
process of solving the matrix equation (Eq 26) is continued until the increments in the variables
x y and z is less than a very small quantity The iteration process is then said to be
29
converged and the values of the variables at convergence of the solution are the roots of the
system of the three fusion equations
The composition of LiNO3 NaNO3 and KNO3 and the eutectic temperature is solved by
using the Newton-Raphson iterative method Different from the data in previous literature the
eutectic temperature for the ternary is 116oC Besides the composition for each component is
also different from those published in literatures The new molten ternary system is composed of
2592 wt LiNO3 2001 wt NaNO3 and 5407 wt KNO3 The similar method is also applied
to other multi-component systems to determine the composition and eutectic temperature The
predicted melting points for new solar energy storage system are given Table41
Table 41 Calculated composition and melting point of multi-component molten salts systems
System Composition (wt) Calc Tmp
LiNO3 NaNO3 KNO3 NaNO2 KNO2 Mg(NO3)2 MgKN (degC)
Salt 1 259 20 541 - - - - 116
Salt 2 - 161 547 292 - - - 1238
Salt 3 175 142 505 178 - - - 986
Salt 4 115 104 274 - - - 507 986
Salt 5 172 139 476 172 41 - - 957
Salt 6 9 423 336 - 151 - - 1000
Salt 7 193 - 546 237 24 - - 1081
Salt 8 193 - 559 239 - 09 - 1008
Salt 9 154 172 324 - - 83 267 1036
30
CHAPTER 5
EXPERIMENTAL PROCEDURE
51 Melting point determination of molten salt mixtures
511 Materials
Ternary quaternary and quinary nirate and nitrite mixtures were tested in the thesis Most
components in the mixtures don‟t require any pre-preparation and can be used as received The
only exception is new developed MgKN which was composed of 6667 mol KNO3 and 3333
mol Mg(NO3)2 This unique compound is synthesized from magnesium nitrate hexahydrate
(98 Alfa Aesar) and potassium nitrate (ACS 990 min Alfa Aesar) and added into the
mixture as one single component As received magnesium nitrate hexahydrate is dehydrated
before synthesizing MgKN compound Weighted amount of magnesium nitrate taken in a
stainless steel crucible and placed on a hot plate in an argon atmosphere Temperature of the salt
is measured with a thermocouple immersed in the salt The temperature was held at 52315 K for
2 hours The salt solidifies to a white mass The temperature of the salt is then raised to 57315 K
slowly to remove any traces of moisture and to ensure complete dehydration The complete
removal of water is ascertained by weight loss
512 Apparatus and Procedure
31
Differential scanning calorimetry (DSC) analysis was performed using Perkin Elmer
Diamond DSC instrument and the setup is shown in fig 51 Heat flow and temperature can be
recorded in the instrument with an accuracy of 00001 mW and 001 K respectively The
measurements were made under purified nitrogen atmosphere with a flow rate of 20ccmin and at
a heating rate of 5 Kmin
Fig 51 Photography of set-up for DSC equipment
After dehydration if necessary each component was weighed to an accuracy of 01mg with
the electrical balance and mixed thoroughly in a stainless steel crucible Later the mixture is
heated up to certain temperature at which the entire salt melts At this temperature the salt
mixture was held for about 30 minutes The salt mixture is allowed to air cool to ambient
temperature This procedure is repeated 3 to 4 times to get the well-mixed compound Standard
aluminum pan with lid used for DSC measurements are weighed before the experiment Small
amount of the synthesized compound is placed carefully in the aluminum pan and closed with
the lid The lid is crimped by a sample press and the pan is weighed The weight of the sample is
32
determined by removing the weight of the pan and lid For the determination of melting point
and heat capacity (20-25) mg of the sample was used
Perkin-Elmer Diamond Differential Scanning Calorimeter (DSC) is used to measure the
melting point and heat capacity of compound The crimped ample pan was immediately put
inside the sample chamber of DSC after preparation and held at 52315 K for 10 hours to remove
the trace amount of moisture possibly caught in the process of loading sample and also to ensure
a homogeneous mixture In the experimental procedure a temperature range from 29815 K to
52315 K was set with a heating rate of 5 K min
1 followed by a cooling cycle at the same rate
This cycle is repeated for at least 6 times to ensure good mixture of the sample and
reproducibility of the results
52 Heat Capacity determination of molten salt mixtures
To start Cp measurement the same procedure as that of melting point determination is
followed with an addition of bdquoiso-scan-iso‟ steps to the program after 5-cycle temperature scan
Starting from 29815 K the temperature was held for 5 minutes before and after each scan step
Small temperature scan range is chosen to avoid thermal resistance between device and testing
sample except when the temperature is approaching the melting temperature The upper limit for
the Cp measurement was set to 62315 K in our experiments Since the change in the molar heat
capacity of the salt in the liquid state is very small the Cp data in the liquid state can be easily fit
to an equation and extrapolated to higher temperatures To get the value of molar heat capacity
of the sample heat flow curve for the baseline of the empty sample pan also needs to be obtained
immediately following the identical ldquoiso-scan-isordquo steps which were used for the actual sample
33
run The difference of heat flow between the actual crimpled sample and the empty sample pan is
the absolute heat absorbed by the test sample
53 Density determination of molten salt mixtures
Density measurement was carried out with standard densitometer which has fixed volume
Initial weight of the densitometer is measured and noted Salt composition of which the density
is measured is placed in a beaker on a hot place The densitometer is also placed on the same hot
plate The temperature is set to a fixed value above the melting point of the salt and is measured
by a thermocouple After the salt is melted and when the temperature shows stable reading the
molten salt is poured in to the densitometer up to the set mark on the sensitometer bottle The
weight of the densitometer with the molten salt is measured The weight difference between this
weight and the weight of empty densitometer gives the weight of the molten salt at the fixed set
temperature By knowing the fixed volume in the densitometer the density of the salt at that
temperature can be calculated This procedure is repeated at least three times to accurately
determine the density of the salt
34
CHAPTER 6
RESULT AND DISCUSSION
61 Melting point determination
611 DSC equipment calibration
Before the actual melting point measurement pure indium zinc metal and several
individual salts were used to calibrate the DSC equipment For metals only one sharp peak was
observed for each and the heat flow curve for indium metal is shown in fig 61 However larger
and boarder peaks are found for salts just like the condition illustrated in fig 62 for pure
potassium nitrate Based on the results shown in Table 61 the experimental data for melting
points and enthalpies of fusion have excellent agreement with the literature values [60-63] The
variation of point is within 07 and the variation of change of enthalpy is less than 3
Figure 61 Melting point calibration with indium sample
35
Figure 62 Melting point calibration with KNO3 sample
Table 61 Calibration data of melting points with different samples
Sample
Lit
Tmp
Expt
Tmp
Lit
Ttrans
Expt
Ttrans
Lit
ΔHfusion
Expt
ΔHfusion
Lit
ΔHtrans
Expt
ΔHtrans
degC degC degC degC Jg Jg Jg Jg
Indium 1566 1563 - - 286 278 - -
Zinc 4195 4188 - - 1086 1068 - -
LiNO3 2567 2550 - - 3617 3633 - -
NaNO3 3100 3081 2770 2753 1777 1756 147 152
KNO3 3370 3372 1330 1332 993 1005 538 529
612 Results
Differential scanning calorimetry (DSC) was used to determine the melting point and any
solid state phase transitions of the salt mixture A low scanning rate was chosen to record the
heat flow curve as function of temperature in order to improve the sensitivity of detection [64] It
helps to pick up any small endothermic peaks and also avoids the thermal resistance between the
36
internal furnace and sample Nine systems were chosen to test and the eutectic composition is
already listed in Table 41
All the selected systems are composed of alkaline nitrate and nitrite and most of them have
three basic components which are lithium sodium potassium nitrate or nitrite All the quaternary
and quinary systems were developed on the basis of the LiNO3-NaNO3-KNO3 baseline ternary
Figure 63-611 shows the DSC plot of all the salt systems DSC plots for each system were
collected for at least five runs (each run with fresh salt preparation) to ensure the reproducibility
All the onset temperatures peak temperatures predicted temperatures enthalpy of fusion for
melting peaks and the solid phase transformation temperatures are given in Table62
Figure 63 DSC endothermic peaks of LiNO3-NaNO3-KNO3 salt
37
Figure 64 DSC endothermic peaks of NaNO3-NaNO2-KNO3 salt
Figure 65 DSC endothermic peaks of LiNO3-NaNO3-KNO3-MgK salt
38
Figure 66 DSC endothermic peaks of LiNO3-NaNO3-KNO3-NaNO2 salt
Figure 67 DSC endothermic peaks of LiNO3-NaNO3-NaNO2-KNO3-KNO2 salt
39
Figure 68 DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt
Figure 69 DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt
40
Figure 610 DSC endothermic peaks of LiNO3-KNO3-NaNO2-Mg(NO3)2 salt
Figure 611 DSC endothermic peaks of LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN salt
Table 62 illustrates that the predicted melting point is close to the experimental
determined value and most deviation is within 10 except for system 9 The great agreement
41
between experimental and calculated data verifies the accuracy and feasibility of the
thermodynamic modeling
Table 62 DSC results of melting point transition point and predicted melting point
System Tmp Ttrans ΔHfusion
Calculated degC Onset degC Peak degC Peak degC Jg
Salt 1 1160 994 1191 1043 600
Salt 2 1238 1150 1240 NA 97
Salt 3 986 940 999 NA 244
Salt 4 986 940 1010 NA 60
Salt 5 957 910 950 NA 62
Salt 6 1000 930 960 NA 86
Salt 7 1081 992 1003 793 60
Salt 8 1008 1010 1019 853 59
Salt 9 1036 834 892 NA 93
613 Discussion
It is observed that the first curve is different from last ones shown in the DSC plots and
this phenomenon is common for all the melting point measurement with DSC technique This
happened because in the first cycle the moisture caught by salt mixture especially the lithium
nitrate was removed in the process of heating Moreover the partially solidified sample in the
sample loading process can be re-homogenized in the first heating cycle [65-67] In figure 63
69 and 610 more than one endothermic peak was found The first smaller endothermic peak
refers to solid state phase transition of the salt mixture The second larger endothermic peak
refers to the melting of the salt Normally the onset temperature of transition is taken as the
experimental transition point for any metallic sample However in case of molten salts mixtures
since the thermal conductivity is low [68-74] the complete transition is ensured only at the peak
42
transition temperature The thermal gradient which exists due to the low thermal conductivity of
the salt results in internal heat flow which enhances the mixing in the salt Thus the transition
temperature is defined as the peak temperature of phase transition For salt No1 the small
endothermic peak happened before and was connected to the main peak which occurred at
39027K The first endothermic peaks for salt No 7 and 8 occurred at almost the same
temperature because of the similar composition for these two compounds Since the small
amount of magnesium nitrate and potassium nitrite contained in these two compounds the small
endothermic peak can hardly be related to these two components Obviously the rest three major
components must have something to do with the first peaks happened before the melting peaks
for both cases Each component among the major three ones were tested to find out any possible
solid phase transition peaks of them and the results shown in Table 63 which reveals that
lithium nitrate doesnt have any phase transition peak in solid state while potassium nitrate and
sodium nitrite both own the solid phase transformation peaks before their melting peaks
Table 63 Fusion and solid phase transition temperature for individual salts
System Tmp degC Ttrans degC ΔHfusion Jg ΔHtrans Jg
LiNO3 2550 - 3633 -
KNO3 3372 1332 1005 529
NaNO2 4311 4170 1119 880
The further investigation was carried out by running the KNO3-NaNO2 (550 wt and 238 wt )
binary compound with the very similar weight percentage as that in salt No 7 (546 wt and
237 wt) and salt No 8 (559wt and 239wt) By converting the weight percentage of the
studied binary system into 100 scale the weight fraction for sodium nitrate and potassium
nitrate can be rewritten as 698wt and 302wt The DSC plot for this binary system was
43
shown in fig 612 Although the solid transition and melting temperature were brought down by
adding lithium nitrate the shape of the plots in fig 69 and 610 are identical to that shown in fig
612 The enthalpy of solid state transformation of the binary salt was also converted to that in
both quaternary systems by using the weight fraction occupied by the binary system and the
comparable change of converted enthalpy between the binary system and two quaternary systems
indicates the relevance of the solid transition peaks in salt 7 and 8 to the combined effect of
potassium nitrate and sodium nitrite
Figure 612 DSC plot of 698wt KNO3- 302wt NaNO2 binary system
The similar analysis was applied to No1 salt to find out the reason for the presence of a
small peak adherent to the main melting peak before the melting point Sodium nitrate and
potassium nitrate binary system was synthesized based on the weight fraction of these two
constituent salts in No 1 salt DSC plot for the sodium nitrate-potassium nitrate binary system in
Fig 613 with the converted composition which is essentially same as that in the No1 ternary
system shows smooth heat flow curve before the melting peak which means the solid transition
peak in ternary is not simply relative to the binary system Assumption was made that the solid
44
phase transformation peak in the ternary salt is resulted from a multiple effect ie the
combination of one of the eutectic binary system involved in the ternary salt mixture and the
other binary system which is composed of the rest components The statement is verified that the
small peak in salt 1 is mainly caused by the solid phase transformation peak in lithium nitrate-
potassium nitrate eutectic binary system given the similar shape of the DSC plots in Fig 614
Since in salt No1 there is excess amount of sodium nitrate to form the lithium nitrate-sodium
nitrate binary system the rest sodium nitrate can interact with potassium nitrate and form new
sodium-potassium nitrate system which is shown in fig615 Besides a solid phase
transformation peak is observed in fig615 which has a very small area and won‟t change the
shape of phase transformation peak in fig614 when these two binary systems are combined and
form salt 1 The enthalpies of solid state transformation in two binary salts were also converted
to that in salt 1 by using the weight fractions occupied by both binary systems The difference
of the change of converted enthalpies between the lithium-potassium nitrate eutectic binary and
ternary system is filled by the binary mixture which is composed of the rest components sodium
nitrate-potassium nitrate The comparable converted values of enthalpy change between salt 1
and its two constituent binary systems further verify the assumption that the solid phase
transformation happened in salt 1 is mainly due to the combined effect of LiNO3-KNO3 eutectic
binary system and NaNO3-KNO3 binary system
45
Figure613 DSC plot of 270wt NaNO3-730wt KNO3 binary system
Figure614 DSC plot of 458wtLiNO3-542wtKNO3 binary system
46
Figure615 DSC plot of 460wt NaNO3-540wt KNO3 binary system
Unlike those discussed mixtures above salt No2 Salt No4 Salt No5 and Salt No6 have
only one relatively board melting peak and the heat flow curve before and after are very stable
Similarly there is no solid transformation peaks observed in salt No3 salt No7 and salt No8
However the heat flow after the melting peak in these cases are not stable and the main
endothermic peak is followed by a small hump which is considered to be the recrystallization
process once the compound entered into the liquid state When the process is finished the heat
flow curve returns to steady state
Heating rate is a significant parameter when collect the heat flow curves by using DSC
technique Fig 616(a) and Fig 616(b) illustrate the difference of melting point for salt No6 due
to the change of heating rate If the heating rate is 20oCmin the peak temperature and onset
temperature for the melting peak is 9669oC and 9221
oC respectively Once the heating rate is
decreased to 5oCmin these two temperatures will also be lowered to 9614
oC and 9190
oC The
difference is resulted from the diverse amount of thermal resistance between the testing sample
and the furnace inside the DSC instrument [75] Under higher heating rate the decisive thermal
47
resistance is raised due to the low thermal conductivity medium between the furnace and the
actual sample The insensitivity of gas heat conduction medium in DSC results each unit of
temperature increase on one side cannot have an immediate response on the other side of the gas
Consequently the sample holder which is connected the furnace has a higher temperature than
that inside the sample In this condition the value of temperature profile collected as the sample
holder temperature is larger than the actual temperature The deviation will be much smaller
when the heating rate is reduced In the case the thermal resistance will be decreased because of
the lower temperature gradient of the gas medium in the heating process As a result of that the
collected temperature from the sensor attached to the sample holder will be very close to the
actual temperature inside the testing sample
Figure 616(a) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 20oCmin
heating rate
48
Figure 616(b) DSC endothermic peaks of LiNO3-NaNO3-KNO3-KNO2 salt for 5oCmin
heating rate
Besides the difference of temperature while using higher and lower heat rate the solution
of DSC will also be affected by different heating rate Fig 617(a) shows the DSC plot for salt
No 7 using the heating rate as 5oCmin and the DSC plot in Fig 617(b) is collected under the
heating rate as 20oCmin It can be observed that in the lower heating rate two small separated
peaks can be viewed as two parts of the solid phase transformation process while in Fig 617(b)
two small peaks before the melting peak merge and present as a board hump The qualification
of resolution can be executed by the term named resolution factor RMKE which is calculated as
the ratio of the peak heat flow value of the separated peaks to that of the concave point between
two peaks The equation for determining RMIKE is given in Eq 27 [76 77]
RMIKE =hpeakhmin [27]
49
Figure 617(a) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 5oCmin
heating rate
Figure 617(b) DSC endothermic peaks of LiNO3-KNO3-NaNO2-KNO2 salt for 20oCmin
heating rate
In the case of lower heating rate the RMKE is determined to be 15 and the value for higher
heating rate is not available because the concave point of heat flow doesn‟t exist from
Fig617(b) Since the higher RMKE value indicates better resolution it can be stated that the
50
lower heating rate also results in greater sensitivity of the equipment to pick up any small
endothermic peaks
Besides the down-selected 9 compounds some more salt mixtures were also tested Most
of them were not selected to the final candidate for the thermal energy storage application
because of their higher melting point Table 64 gives some of the trial systems measured with
DSC technique It is illustrated that the melting points of mixtures with lower or even no content
of lithium nitrate turn out to be higher than those with sufficient amount of lithium nitrate For
most of the mixtures with melting point lower than 120oC the amount of lithium nitrate should
be larger than 81wt Also all of the systems in table 64 with lithium nitrate less than 15wt
have melting point higher than 140oC Based on the observation above it is concluded that the
lithium nitrate can be used as an additive to bring the melting point down for thermal energy
storage systems
51
Table 64 Melting points of candidate systems as function of temperatures
System Composition (wt)
Onset
Temp
Peak
Temp
(oC) (
oC)
LiNO3 ndash NaNO3 ndash KNO2 107 459 434 890 910
LiNO3 - KNO3 - NaNO2 196 564 241
1024 1046
LiNO3 - NaNO3 - KNO3 - KNO2 90 423 337 151
930 960
LiNO3 - NaNO3 - NaNO2 - KNO2 81 454 65 401
900 910
LiNO3 - KNO3 - NaNO2 - KNO2 193 546 237 24
992 1003
LiNO3 - KNO3 - NaNO2 ndash Mg(NO3)2 193 559 238 09
1010 1020
LiNO3 - NaNO3 - KNO3 - Mg(NO3)2
- MgK 154 172 324 83 267 834 892
LiNO3 - NaNO3 - KNO2 ndash Ca(NO3)2 14 390 333 263
1250 1470
NaNO3 - KNO3 - NaNO2 - KNO2 425 163 71 341
1407 1447
NaNO3 - KNO3 - KNO2 ndash Mg(NO3)2 432 146 380 42
1386 1421
NaNO3 - NaNO2 - KNO2 - Ca(NO3)2 451 92 410 48
1150 1390
LiNO3 - NaNO3 - NaNO2 - KNO2 -
Ca(NO3)2 15 393 37 323 232 1380 1480
LiNO3 - NaNO3 - KNO2 - Ca(NO3)2 -
Mg(NO3)2 14 379 313 275 20 1339 1534
62 Heat capacity determination
621 Heat capacity calibration
DSC was also calibrated for the heat capacity measurement Lithium nitrate sodium
nitrate and potassium nitrate were examined for the heat capacities from room temperature to
upper limit temperature for the instrument In liquid state the heat capacity values for each salt
can be fit to straight line with trace amount of increasing trend Since the temperature range from
the onset temperature of liquid state to the upper limit of DSC is relatively small the heat
capacity values for pure individual salts can be viewed as constants The comparison between the
theoretical and experimental heat capacity data is given in Table 65 Except lithium nitrate the
52
experimental heat capacities data for the rest two systems are almost same as the literature Even
for lithium nitrate which demonstrates the biggest difference from the literature data the 28
vibration is still within a reasonable range
Table 65 Calibration data of heat capacities with different samples
Sample Lit Cp Expt Cp
JgK JgK
LiNO3 218 212
NaNO3 169 167
KNO3 140 139
622 Results
The materials used in the heat capacity measurements are the same as those in the melting
point experiments Molar heat capacities of the all compound were measured by the DSC
equipment from room temperature to 62315 K The heat flow is recorded as a function of
temperature in ldquoiso-scan-isordquo steps at intervals of 20 K The bdquoiso stage‟ refers to isothermal
holding at a particular temperature bdquoscan stage‟ refers to the heat flow recording at a heating rate
of 5 K min1
up to a an increment of 25 K followed by another isothermal holding stage This is
a standard procedure followed in the measurement of heat capacity of materials using the DSC
equipment [63 64] This procedure of heat capacity measurement has two advantages (i) any
heat fluctuations during the recording are avoided by the isothermal steps and (ii) any phase
transition can be highlighted by the choice of temperature range The absolute heat flow to the
sample is determined by subtracting the heat flow collected by running a baseline curve with an
empty pan Because the heat capacity measurement in the heating process corresponds to
53
collecting the value of required heat flow at each temperature all the heat capacity plots have the
same shape with that of heat flow in the melting point measurements Take the heat capacity plot
of LiNO3-NaNO3-KNO3 ternary system as an instance which is shown in fig 618 the heat
capacity curve also has two different peaks The first little peaks corresponds to one occurs at
39027K which was observed in fig 63 the second large and sharp peak happened right after the
small one is prevalent to the endothermic peak with the peak temperature as 39027 K Similarly
after the phase transformation the heat capacity in liquid state becomes very stable and increase
with temperature linearly with little slope
Fig 618 Heat capacity data plot of LiNO3-NaNO3-KNO3 ternary system as function of
temperature
The heat capacity change as function of temperature for salt No1 was illustrated in fig
619 Based on the trend of heat capacity in the liquid state any value for the system in the liquid
can be extrapolated The expressions for heat capacity in liquid state for the new molten salt
systems were discussed and given in the next sectionTable66 shows the specific heat capacity
54
of the all the selective compounds measured at 62315 K and extrapolated at 77315K Besides
the molar heat capacities at 77315K are given in Table 66 of all the salts
Fig 619 Heat capacity of LiNO3-NaNO3-KNO3 in liquid state from 40315-62315K
Table 66 Heat capacity of selected new TES molten salt mixtures
System Expt (62315K) Extrapolated(77315K) Extrapolated(77315K)
Cp JgK Cp JgK Molar Cp JmolK
Salt 1 153 170 1521
Salt 2 143 168 1515
Salt 3 148 155 2183
Salt 4 153 166 1411
Salt 5 153 170 1440
Salt 6 151 163 1435
Salt 7 156 167 1443
Salt 8 155 168 1410
Salt 9 161 170 1937
55
623 Thermodynamic properties
The standard thermodynamic properties such as entropy enthalpy and Gibbs energy for
salt mixtures are determined from the experimental data of melting point and heat capacity in the
temperature range of the present study and expression for determining these properties are given
in equation 28-30 In thermodynamics all these three properties are related to heat capacity and
its variances with temperature In the studied temperature range (29815K-62315K) they can be
described as expression includes heat capacity
[28]
[29]
[30]
Where Tt is the solid transformation temperature Tmp is the melting point ΔHt is enthalpy of
solid phase transformation and ΔHfusion is enthalpy of fusion The standard thermodynamic
properties entropy enthalpy and Gibbs energies as function of temperature for each compound
are expressed in the following section
6231 LiNO3-NaNO3-KNO3 (Salt 1)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3
compound (i) solid state 1 (32315-38415) K (ii) liquid state (40315-62315) K Accordingly
56
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62311 Heat capacity of solid state 1 (29815-38415) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the solid state 1 in the
temperature range of 29815 to 38415 K is fit to a second order polynomial equation Eqn (31)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[31]
( ) K
R2 = 0982
62312 Heat capacity of liquid state (40315-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a linear equation Eqn (32) gives the linear
equation along with the least square fit parameter (R2) in the temperature range for the liquid
state of the compound
JKmol [32]
57
R2 = 0947
Heat capacity data of the LiNO3-NaNO3-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62313 Thermodynamic properties of solid state 1(29815-38415) K
JKmol [33]
Jmol [34]
[35]
Jmol
62314 Thermodynamic properties of liquid state 2(40315-62315) K
[36]
58
JKmol
Jmol [37]
[38]
Jmol
Among the equations above equation (33)-(35) refer to the thermodynamic properties for
solid state equations (36)-(38) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature ranges for solid and liquid state are
given in Table A1 and A2 in appendix A respectively with the corresponding heat capacity as
function of temperature
6232 NaNO3-NaNO2-KNO3 (Salt 2)
The heat capacity data can be divided into two sections for NaNO3-NaNO2-KNO3
compound (i) solid state 1 (32315-39215) K (ii) liquid state (41315-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62321 Heat capacity of solid state 1 (29815-39215) K
59
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the solid state in the
temperature range of 29815 to 39215 K is fit to a second order polynomial equation Eqn (39)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[39]
( ) K
R2 = 0978
62322 Heat capacity of liquid state (40315-62315) K
The heat capacity data for NaNO3-NaNO2-KNO3 compound in the liquid state in the
temperature range of 40315 to 62315 K is fit to a second order polynomial equation Eqn (40)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[40]
R2 = 0941
60
Heat capacity data of the NaNO3-NaNO2-KNO3 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62323 Thermodynamic properties of solid state 1(29815-39215) K
JKmol [41]
Jmol [42]
[43]
Jmol
62324 Thermodynamic properties of liquid state 2(40315-62315) K
JKmol [44]
61
Jmol [45]
[46]
Jmol
Among the equations above equation (41)-(43) refer to the thermodynamic properties for
solid state equations (44)-(46) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table B1 and B2 in appendix B respectively with the corresponding heat capacity as
function of temperature
6233 LiNO3-NaNO3 -KNO3-MgK (Salt 3)
The heat capacity data can be divided into two sections for LiNO3-NaNO3 -KNO3-MgK
compound (i) solid state 1 (29815-36415) K (ii) liquid state (42115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62331 Heat capacity of solid state 1 (29815-36415) K
62
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the solid state in the
temperature range of 29815 to 36415 K is fit to a second order polynomial equation Eqn (47)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[47]
( ) K
R2 = 0995
62332 Heat capacity of liquid state (42115-62315) K
The heat capacity data for LiNO3-NaNO3 -KNO3-MgK compound in the liquid state in the
temperature range of 42115 to 62315 K is fit to a second order polynomial equation Eqn (48)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[48]
R2 = 0963
63
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
62333 Thermodynamic properties of solid state 1(29815-36415) K
JKmol [49]
Jmol [50]
[51]
Jmol
62334 Thermodynamic properties of liquid state 2(42115-62315) K
64
JKmol [52]
Jmol [53]
[54] [29]
Jmol
Among the equations above equation (49)-(51) refer to the thermodynamic properties for
solid state equations (52)-(54) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table C1and C2 in appendix C respectively with the corresponding heat capacity as
function of temperature
6234 LiNO3-NaNO3-KNO3-NaNO2 (Salt 4)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-NaNO2
compound (i) solid state 1 (29815-36315) K (ii) liquid state (38115-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62341 Heat capacity of solid state 1 (29815-36315) K
65
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the solid state in the
temperature range of 29815 to 36315 K is fit to a second order polynomial equation Eqn (55)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[55]
( ) K
R2 = 0995
62342 Heat capacity of liquid state (38115-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-NaNO2 compound in the liquid state in the
temperature range of 38115 to 62315 K is fit to a second order polynomial equation Eqn (56)
gives the linear equation along with the least square fit parameter (R2) in the temperature range
for the liquid state of the compound
[56]
R2 = 0972
Heat capacity data of the LiNO3-NaNO3 -KNO3-MgK compound in the solid state follows
a second order polynomial curve whereas the heat capacity is linear in the liquid state
66
62343 Thermodynamic properties of solid state 1(29815-36315) K
JKmol [57]
Jmol [58]
[59]
Jmol
62344 Thermodynamic properties of liquid state 2(38115-62315) K
JKmol [60]
Jmol [61]
67
[37]
Jmol [62]
Among the equations above equation (57)-(59) refer to the thermodynamic properties for
solid state equations (60)-(62) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table D1 and D2 in appendix D respectively with the corresponding heat capacity as
function of temperature
6235 LiNO3-NaNO3-NaNO2-KNO3-KNO2 (Salt 5)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-NaNO2-KNO3-
KNO2 compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62351 Heat capacity of solid state 1 (29815-35915) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
in the temperature range of 29815 to 35915 K is fit to a second order polynomial equation Eqn
(63) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
68
[63]
( ) K
R2 = 0996
62352 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the liquid
state in the temperature range of 37515 to 62315 K is fit to a second order polynomial equation
Eqn (64) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[64]
R2 = 0969
Heat capacity data of the LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound in the solid state
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62353 Thermodynamic properties of Solid state 1(29815-35915) K
JKmol [65]
69
Jmol [66]
[67]
Jmol
62354 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [68]
Jmol [69]
[45]
Jmol [70]
70
Among the equations above equation (65)-(67) refer to the thermodynamic properties for
solid state equations (68)-(70) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
given in Table E1 and E2 in appendix E respectively with the corresponding heat capacity as
function of temperature
6236 LiNO3-NaNO3-KNO3-KNO2 (Salt 6)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-KNO2
compound (i) solid state 1 (29815-35915) K (ii) liquid state (37515-62315) K Accordingly
the heat capacity data are fit to two separate polynomial equations corresponding to the three
phases of the compound
62361 Heat capacity of solid state 1 (29815-36515) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the solid state in the
temperature range of 29815 to 36515 K is fit to a second order polynomial equation Eqn (71)
gives the polynomial equation along with the least square fit parameter (R2) in the temperature
range for the solid state 1 of the compound
[71]
( ) K
R2 = 0998
71
62362 Heat capacity of liquid state (37515-62315) K
The heat capacity data for LiNO3-NaNO3-KNO3-KNO2 compound in the liquid state in the
temperature range of 37515 to 62315 K is given in Table 20 The data is fit to a second order
polynomial equation Eqn (72) gives the linear equation along with the least square fit parameter
(R2) in the temperature range for the liquid state of the compound
[72]
R2 = 0953
Heat capacity data of the LiNO3-NaNO3-KNO3-KNO2 compound in the solid state follows a
second order polynomial curve whereas the heat capacity is linear in the liquid state
62363 Thermodynamic properties of solid state 1(29815-35915) K
JKmol [73]
Jmol [74]
72
[75]
Jmol
62364 Thermodynamic properties of liquid state 2(37515-62315) K
JKmol [76]
Jmol [77]
Jmol [78]
Among the equations above equation (73)-(75) refer to the thermodynamic properties for
solid state equations (76)-(78) refer to thermodynamic properties of the liquid The entropy
enthalpy and Gibbs energy values in the studied temperature range for solid and liquid state are
73
given in Table F1 and F2 in appendix F respectively with the corresponding heat capacity as
function of temperature
6237 LiNO3-KNO3-NaNO2-KNO2 (Salt 7)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62371 Heat capacity of solid state 1 (29815-35415) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 1 in
the temperature range of 29815 to 35415 K is fit to a second order polynomial equation Eqn
(79) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[79]
(29815-35415) K
R2 = 0993
62372 Heat capacity of solid state 2 (36215-37315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the solid state 2 in
the temperature range of 36215 to 37315 K is fit to a second order polynomial equation Eqn
74
(80) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 2 of the compound
[80]
R2 = 0977
62373 Heat capacity of liquid state (37915-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-KNO2 compound in the liquid state in the
temperature range of 37915 to 62315 K is fit to a linear equation Eqn (81) gives the
polynomial equation along with the least square fit parameter (R2) in the temperature range for
the liquid state of the compound
[81]
R2 = 0961
Heat capacity data of the LiNO3-KNO3-NaNO2-KNO2 compound in the two solid states
follows a second order polynomial curve whereas the heat capacity is linear in the liquid state
62374 Thermodynamic properties of solid state 1(29815-35415) K
75
JKmol [82]
Jmol [83]
[84]
Jmol
62375 Thermodynamic properties of solid state 2(36215-37315) K
JKmol [85]
Jmol [86]
76
[87] [62]
Jmol
62376 Thermodynamic properties of liquid state (37915-62315) K
JKmol [88]
Jmol [89]
Jmol [90]
Among the equations above equation (82)-(84) refer to the thermodynamic properties for
solid 1 equation (85)-(87) refer to the thermodynamic properties for solid 2 equations (88)-(90)
refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy values
77
in the studied temperature range for solid 1 solid 2 and liquid state are given in Table G1-G3 in
appendix G respectively with the corresponding heat capacity as function of temperature
6238 LiNO3-KNO3-NaNO2-Mg(NO3)2 (salt 8)
The heat capacity data can be divided into three sections (i) solid state 1 (29815-35415)
K (ii) solid state 2 (36215-37315) K (iii) liquid state (37915-62315) K Accordingly the heat
capacity data are fit to three separate polynomial equations corresponding to the three phases of
the compound
62381 Heat capacity of solid state 1 (29815-33715) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid
state 1 in the temperature range of 29815 to 33715 K is fit to a second order polynomial
equation Eqn (91) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the solid state 1 of the compound
[91]
(29815-33715) K
R2 = 0994
62382 Heat capacity of solid state 2 (36115-36415) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the solid state 2
in the temperature range of 36115 to 36415 K is given in Table 4 The data is fit to a second
78
order polynomial equation Eqn (92) gives the polynomial equation along with the least square
fit parameter (R2) in the temperature range for the solid state 2 of the compound
[92]
R2 = 0992
62383 Heat capacity of liquid state (41115-62315) K
The heat capacity data for LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the liquid state in
the temperature range of 41115 to 62315 K is given in Table 5 The data is fit to a linear
equation Eqn (93) gives the polynomial equation along with the least square fit parameter (R2)
in the temperature range for the liquid state of the compound
[93]
R2 = 0934
Heat capacity data of the LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in the two solid
states follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62384 Solid state 1(29815-35415) K
79
JKmol [94]
Jmol [95]
[96]
Jmol
62385 Solid state 2(36115-36415) K
JKmol [97]
80
Jmol [98]
[99] [74]
Jmol
62386 Liquid state (41115-62315) K
JKmol [100]
Jmol [101]
Jmol [102]
Among the equations above equation (94)-(96) refer to the thermodynamic properties for
solid 1 equation (97)-(99) refer to the thermodynamic properties for solid 2 equations (100)-
(102) refer to thermodynamic properties of the liquid The entropy enthalpy and Gibbs energy
81
values in the studied temperature range for solid 1 solid 2 and liquid state are given in Table H1
and H2 in appendix H respectively with the corresponding heat capacity as function of
temperature
6239 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK(Salt 9)
The heat capacity data can be divided into two sections for LiNO3-NaNO3-KNO3-
Mg(NO3)2-MgK compound (i) solid state 1 (29815-35315) K (ii) liquid state (39115-62315) K
Accordingly the heat capacity data are fit to two separate polynomial equations corresponding to
the three phases of the compound
62391 Heat capacity of solid state 1 (29815-35315) K
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state in the temperature range of 29815 to 35315 K is fit to a second order polynomial equation
Eqn (103) gives the polynomial equation along with the least square fit parameter (R2) in the
temperature range for the solid state 1 of the compound
[103]
( ) K
R2 = 0996
62392 Heat capacity of liquid state (39115-62315) K
82
The heat capacity data for LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the liquid
state in the temperature range of 39115 to 62315 K is fit to a second order polynomial equation
Eqn (104) gives the linear equation along with the least square fit parameter (R2) in the
temperature range for the liquid state of the compound
[104]
R2 = 0951
Heat capacity data of the LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK compound in the solid
state follows a second order polynomial curve whereas the heat capacity is linear in the liquid
state
62393 Solid state 1(29815-35315) K
JKmol [105]
Jmol [106]
83
[107]
Jmol
62394 Liquid state 2(39115-62315) K
JKmol [108]
Jmol [109]
[110]
Jmol
Among the equations above equation (105)-(107) refer to the thermodynamic properties
for solid state equations (108)-(110) refer to thermodynamic properties of the liquid The
entropy enthalpy and Gibbs energy values in the studied temperature range for solid and liquid
state are given in Table I1 and I2 in appendix I respectively with the corresponding heat
capacity as function of temperature
84
624 Discussion of Gibbs energy change for molten salts
The Gibbs energy change data as function of temperature for 9 systems are given in fig
620 and the values at 62315K are shown in Table 67 Every system demonstrates continuous
curve throughout the whole studied temperature range Most of systems have similar Gibbs
energy change values for each temperature spot due to the comparable compositions and
properties of constituent salts However salt 3 and salt 9 Both of these salts have certain
amount of MgKN compound which presents large absolute amount of change of Gibbs energy in
the same studied temperature range [66] Since the change of Gibbs energy for multi-component
mixture is relevant to that of each constituent salt the large absolute value of ΔG of MgKN
mainly contributes to the largely negative value of salt 3 and salt 9 shown in fig 620 Besides
it is observed that most systems contain nitrite salts present lower absolute value of Gibbs energy
change For example salt 1 doesn‟t include any nitrite salt and has a relatively high absolute
value of Gibbs energy change as 1704kJmol while other systems having nitrite salts show lower
value varies from 1372kJmol to 1592kJmol
85
Fig 620 Change of Gibbs energy as function of temperature for molten salt systems
Table 67 Change of Gibbs energy values at 62315K for molten salt systems
SNo System ΔG(kJmol)
1 LiNO3-NaNO3-KNO3 1704
2 NaNO3- NaNO2- KNO3 1372
3 LiNO3- NaNO3- KNO3- MgKN 2807
4 LiNO3- NaNO3- KNO3- NaNO2 1443
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1441
6 LiNO3-NaNO3-KNO3-KNO2 1570
7 LiNO3-KNO3-NaNO2-KNO2 1592
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1583
9 LiNO3-NaNO3-KNO3-Mg(NO3)2 -MgKN 2217
86
63 Density determination
631 Density calibration
Several pure molten salts are used to calibrate the density measurement set-up before the
actual density measurement All the density values decrease as function of temperature in the
liquid state and follow the same linear equations as described in eq 4 The experimental values
at 350oC for KNO3 NaNO3 and LiNO3 are selected to compare with the literature data at the
same temperature The results are shown in Table 68 Based on the comparison of the literature
data and the experimental data the variation of density for molten nitrate salt is within in 4
Table 68 Calibration of density measurements with different pure nitrate salts
Sample Literature density Experimental density
gcm3 gcm
3
LiNO3 1727 1701
NaNO3 2066 2144
KNO3 1860 1855
632 Results and discussions
The density result of the salt as function of temperature is plotted for all the salts in Figure
621 and Figure 622 It is observed that the temperature dependence of density above the
melting point is different from that in solid state As known in solid state the density of salt has
an exponential relation with temperature while in these liquid cases the density values have
linearly dependence with temperature The stable variation as function of temperature allows the
extrapolation of density at even higher temperature The regression analysis is performed to get
the coefficient used for describing eq 4 and the results for the coefficients are shown in
87
Table69 [78-80] It is observed that the change of composition is implied on the coefficient A
which indicates the initial point at 150oC The temperature dependence coefficient B doesn‟t
change much with composition which may be mainly affected by the group of anion and cation
Table 69 Coefficient A and B for density determination of salt 1-salt 9
Salt No System A Btimes10
3
(gcm3) (gcm
3degC)
1 LiNO3-NaNO3-KNO3 2032 0493
2 NaNO3- NaNO2- KNO3 2081 0570
3 LiNO3- NaNO3- KNO3-MgKN 2055 0526
4 LiNO3- NaNO3- KNO3- NaNO2 2033 0520
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 2018 0485
6 LiNO3-NaNO3-KNO3-KNO2 2060 0554
7 LiNO3-KNO3-NaNO2-KNO2 2048 0554
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 2044 0524
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 2060 0566
Figure 621 The densities of the salt 1-salt 5 as function of temperature
88
In figure 621 all the density values are clustered around 198gcm3 at 150
oC to
186gcm3 at high temperature end and the deviation of density between all the mixtures is within
in 0047g cm3 Among all the salt mixtures the NaNO3-NaNO2-KNO3 ternary system
demonstrates the highest density value throughout the studied temperature range and LiNO3-
NaNO3-KNO3 ternary system LiNO3- NaNO3-KNO3-NaNO2 quaternary system and LiNO3-
NaNO3-KNO3-NaNO2-KNO2 quinary system show densities at the bottom side of Fig 621 For
salt 2 which doesn‟t contain any lithium nitrate the density at every selected temperature spot
is obviously higher than that of salt 1 4 and 5 which have large amount of lithium nitrate
Moreover the salt 3 which contains the relatively small amount of lithium nitrate stays in
between of salt 1 and salt 2 This comparison illustrates that the addition of lithium nitrate has
an offsetting effect on density for molten salt and it is consistent with previous literature reports
[81] The four systems presented in figure 622 also show even closer density values in the
studied temperature range Similarly salt 6 which contains the least lithium nitrate has the
largest density Salt 7 and salt 8 have almost same composition for the three dominating
components as a result of that the density curves for both mixtures are determined by the same
regression coefficient A and B Moreover the larger amount of lithium nitrate involved in these
two salt mixtures contributes to the lower density given in figure622 which further verifies the
significantly offsetting effect of lithium nitrate on density
89
Figure 622 The densities of the salt 6-salt 9 as function of temperature
The salt mixtures with maximum and minimum amount of lithium nitrate were plotted and
compared with equimolar NaNO3-KNO3 binary system and pure KNO3 salt in Fig623 [82 83]
It is observed that the NaNO3-KNO3 binary system has very similar density value to that of salt
2 because of the analogous type and composition of component in both salts The density of
pure KNO3 is slightly lower than the binary salt mixture which indicates the density of NaNO3 is
close to but higher than KNO3 in the studied temperature range Salt 1 shows the lowest density
in Fig623 due to the offsetting effect on density caused by lithium nitrate which has been
discussed above
90
Figure 623 Density of the salt 1 salt 2 as function of temperature compared to the
equimolar NaNO3-KNO3 binary system and pure KNO3
64 Thermal energy storage density of molten salts
The energy density which is considered as one of the most significant parameters of TES
application can be evaluated by calculation based on the measured density heat capacity and
working temperature range The equation of the thermal energy storage density (E) at working
temperature of 500oC is expressed in equation 111
E = Cp (500-Tm) [111]
Where Cp and are extrapolated heat capacity and density at 500oC respectively Tm is
melting point for salt mixture The extrapolation of density and heat capacity is based on the
linear temperature dependence for both parameters in molten state and the values are shown in
Table 610
91
Table 610 Extrapolated value of density and heat capacity at 500oC of salt 1-salt 9
Salt
No System
Density Heat Capacity
(gmL) (JgK)
1 LiNO3-NaNO3-KNO3 1785 170
2 NaNO3- NaNO2- KNO3 1796 168
3 LiNO3-NaNO3-KNO3-MgK 1773 155
4 LiNO3- NaNO3- KNO3- NaNO2 1792 166
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1796 170
6 LiNO3-NaNO3-KNO3-KNO2 1783 163
7 LiNO3-KNO3-NaNO2-KNO2 1771 167
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1782 168
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgK 1777 170
The calculated energy density for each salt is given in Table 611 compared with that of
solar salt (NaNO3-KNO3) All the new synthesized salt mixtures have significantly higher energy
density than solar salt and salt 3 shows the highest energy density among the new salts
Although salt 1 has higher heat capacity and good melting point the energy density is still the
lowest among new salt mixtures given by the effect of low density The conclusion can be drawn
from these observations that the energy density is a property affected by multiple parameters and
every part plays an important role in determining the efficiency of energy storage of salt
mixtures
92
Table 611 Energy density of salt 1-salt 9 compare to solar salt
The gravimetric storage density of new molten salts are listed in Table 612 and compared
with those different storage systems in fig 624 It is found that in the parabolic trough working
temperature range the gravimetric storage densities of new molten salts are located on the higher
side Even though some reported sensible energy storage liquids have larger gravimetric density
values than the new salts the maximum working temperatures reveal the instable working
condition at 500oC Taking conversion efficiency thermal stability and gravimetric storage
density into considerations the new molten salts are the most suitable choices of the sensible
heat storage for parabolic trough application
Salt No System Energy Density
500degC (MJm3)
0 NaNO3- KNO3 756
1 LiNO3-NaNO3-KNO3 1162
2 NaNO3- NaNO2- KNO3 1135
3 LiNO3-NaNO
3-KNO
3-MgKN 1099
4 LiNO3- NaNO
3- KNO
3- NaNO
2 1189
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 1232
6 LiNO3-NaNO3-KNO3-KNO2 1174
7 LiNO3-KNO3-NaNO2-KNO2 1183
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 1192
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 1242
93
Fig 624 Gravimetric storage density comparison of different energy storage systems as
function of temperature
Table 612 Gravimetric storage densities for solar salt and new molten salts
Salt
No System
Gravimetric Storage Density
500degC (kJkg)
0 NaNO3- KNO3 404
1 LiNO3-NaNO3-KNO3 560
2 NaNO3- NaNO2- KNO3 533
3 LiNO3-NaNO
3-KNO
3-MgKN 575
4 LiNO3- NaNO
3- KNO
3- NaNO
2 612
5 LiNO3- NaNO3- NaNO2-KNO3- KNO2 595
6 LiNO3-NaNO3-KNO3-KNO2 594
7 LiNO3-KNO3-NaNO2-KNO2 604
8 LiNO3-KNO3-NaNO2-Mg(NO3)2 610
9 LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN 649
94
CHAPTER 7
CONCLUSION
The melting points of new molten salts were experimentally determined using DSC
Different from metals the melting point was chosen as the peak temperature rather than onset
temperature of the endothermic peak due to the low thermal conductivity and broad phase
transition range of the molten nitride salt mixture All of the nine new molten salts have melting
points from 89oC to 124
oC which are much lower than current sodium-potassium binary solar
salt Some systems such as salt No1 No7 and No8 have solid phase transformation observed
from the DSC plots It is found that the phase transformations of salt No 7 and No 8 are mainly
contributed to the KNO3-NaNO2 binary system while the small solid transformation peak of salt
No1 is resulted from the combined effect of the KNO3-LiNO3 eutectic binary system involved in
the ternary salt and another binary system which is composed of the rest components The
heating rate of DSC was revealed as a significant parameter for the any endothermic peak
determination When using lower heating rate the thermal resistance between the studied sample
and the furnace will be minimal and the resolution of peak detection will be enhanced
The heat capacities of all the multi-component salts (1 to 9) were determined using DSC
and found varying from 143 to 161 JgK at 350oC The heat capacity in the liquid state
demonstrates linear increase trend as function of temperature On the basis of that the heat
capacity was extrapolated to parabolic trough operating temperature of 500oC Besides heat
capacity data as function of temperature are fit to polynomial equation and thermodynamic
95
properties like enthalpy entropy and Gibbs energies of the compound as function of temperature
are subsequently deduced
Experimental measurements of density of multi-component systems were conducted as
function of temperature in their liquid state In liquid state the density values decrease linearly
as temperature increases The results of those mixtures were compared to the solar salt and
individual constituent salts The comparison demonstrates that the addition of lithium nitrate
lowers the density which is consistent with the observation that lithium nitrate has the lowest
density among all the individual salts in the studied temperature range On the basis of densities
heat capacities and the melting points energy storage density for all the new salts were
calculated and compared to the binary solar salt Among all the new molten salt systems
LiNO3-NaNO3-KNO3-Mg(NO3)2-MgKN quinary system (salt 9) presents the largest thermal
energy storage density as well as the gravimetric density values Moreover the larger thermal
energy storage as well as gravimetric storage densities compared to the solar salt indicate the
better energy storage capacities of new salts for solar power generation systems
96
REFERENCES
[1] JF Manwell JG McGowan and AL Rogers Wind Energy Explained-Theory Design and
Application second edition John Wiley and sons Ltd UK 2009
[2] MJ Pasqualetti Morality space and the power of wind-energy landscapes Geographical
Review 90 2000 381-394
[3] DG Fink and HW Beaty Standard Handbook for Electrical Engineers Eleventh Edition
McGraw-Hill New York 1978
[4] R Bertani Geothermal Energy An Overview on Resources and Potential Proceedings of the
International Conference on National Development of Geothermal Energy Use 2009 Slovakia
[5] TA Volk LP Abrahamson EH White E Neuhauser E Gray C Demeter C Lindsey J
Jarnefeld DJ Aneshansley R Pellerin and S Edick Developing a Willow Biomass Crop
Enterprise for Bioenergy and Bioproducts in the United States Proceedings of Bioenergy
2000 October 15-19 2000 Buffalo New York USA
[6] M Asplund N Grevesse and AJ Sauval The new solar abundances-Part I the
observations Communications in Asteroseismology 147 2006 76-79
[7] DRWilliams Sun Fact Sheet NASA 2004
httpnssdcgsfcnasagovplanetaryfactsheetsunfacthtml
[8] U Herrmann Survey of Thermal Energy Storage for Parabolic Trough Power Plants Journal
of Solar Energy Engineering 124 2002 145-152
[9] Rocket Research Company Chemical energy storage for solar thermal conversion SAND79-
8198 Livermore Sandia National Laboratories 1979
97
[10] A Steinfeld and R Palumbo Solar thermochemical process technology Encyclopedia of
Physical Science and Technology 2001 237-256
[11] EA Fletcher Solar thermal processing a review Journal of Solar Energy Engineering
2001 63-74
[12] R W Bradshaw and Nathan P Siegel Molten Nitrate Salt Development for Thermal
Energy Storage in Parabolic Trough Solar Power Systems of the Energy Sustainability 2008
Conference August 10-14 2008 Jacksonville Florida USA
[13] B Kelly H Price D Brosseau and D Kearney Adopting NitrateNitrite Salt Mixtures as
the Heat Transport Fluid in Parabolic Trough Power Plants Proceedings of the Energy
Sustainability 2007 Conference June 27-30 2007 Long Beach CA
[14] H Reilly and G Kolb Evaluation of Molten Salt Power Tower Technology Based on
Experience at Solar Two SAND2001-3674 Sandia National Laboratories 2001
[15] T Wendelin ldquoParabolic Trough VSHOT Optical Characterization in 2005-2006rdquo NREL
wwwnrelgovdocsfy06osti40024pdf
[16] RB Diver C Andraka S Rawlinson V Goldberg and G Thomas The Advanced Dish
Development System Project ASME Proceedings of Solar Forum 2001 Washington DC
[17] S D Odeh G L Morrison and M Behnia Modelling of parabolic trough direct steam
generation solar collectors Solar Energy 62 1998 396-406
[18] V Heinzel H Kungle and M Simon Simulation of a parabolic trough collector ISES
Solar World Congress Harare Zimbabwe 1-10
[19] S D Odeh G L Morrison and M Behnia Modeling of Parabolic Trough Direct
Generation Solar Collectors Solar Energy 62 1998 395-406
[20] Ezzat Optimum Working Fluids for Solar Powered Rankine Cycle Cooling of Buildings
Solar energy 25 1980 235-241
98
[21] R G Reddy Ionic Liquids How well do we know them editorial Journal of Phase
Equilibria and Diffusion 27 2006 210-211
[22] M Zhang and R G Reddy Application of [C4min][Tf2N] Ionic Liquid as Thermal
Storage and Heat Transfer Fluids editor J Weidner ECS Transactions 2 (28) 2007 27-32
[23] M Zhang and R G Reddy Evaluation of Ionic Liquids as Heat Transfer Materials in
Thermal Storage Systems Energy Energy Materials editors F Dogan M Awano D Singh
and B Tuttle ASM International Materials Park Ohio USA MSampT‟07 2007 151-160
[24] R G Reddy Novel Applications of Ionic Liquids in Materials Processing Advanced
Structural and Functional Materials Design 2008 Journal of Physics Conference Series (JPCS)
165 2009 1-6
[25] RW Bradshaw and DE Meeker High-temperature stability of ternary nitrate molten
salts for solar thermal energy systems Solar Energy Materials 21 1990 51-60
[26] AS Trunin Designing and investigations of salt systems for solar energy utilization
Utilization of sun and other radiation sources in materials research Kiev Naukova Dumka 1983
p 228-38
[27] D J Rogers and G J Janz Melting-crystallization and premelting properties of sodium
nitrate-potassium nitrate Enthalpies and heat capacities Journal of Chemical and Engineering
Data 27 1982 424-428
[28] D Kearney U Herrmann P Nava and B Kelly Assessment of a molten salt heat transfer
fluid in a parabolic trough solar field Journal of Solar Energy Engineering 125 2003 170-176
[29] Q Peng J Ding X Wei J Yang and X Yang The preparation and properties of multi-
component molten salts Applied Energy 87 2010 2812-2817
[30] E M Levin C R Robbins and H F McMordie Phase Diagrams for Ceramists American
Ceramic Society 1964
[31] J C Oxley J L Smith E Rogers and M Yu Ammonium nitrate thermal stability and
explosivity modifiers Thermochimica Acta 384 2002 23-45
99
[32] LG Marianowski and HC Maru Latent heat thermal energy storage systems above
4508oC Proceedings of 12th intersociety energy conversion engineering conference 1977 55-
66
[33] HC Maru JF Dullea A Kardas L Paul LG Marianowski E Ong et al Molten salts
energy storage systems Chicago Final Report of the Institute of Gas Technology 1978
[34] WM Philips and JW Stears Advanced latent heat of fusion thermal energy storage for
solar power stations Proceedings of 20th intersociety energy conversion engineering conference
2 1985 384-391
[35] KE Mayo Heat source systems USA Patent 3605720 1971
[36] JI Eichelberger and HD Gillman Investigation of metal fluoride thermal energy storage
material Proceedings of 12th intersociety energy conversion engineering conference 1977 567-
574
[37] GR Heidenreich and MB Parekh Thermal energy storage for organic Rankine cycle solar
dynamic space power systems Proceedings of 21st intersociety energy conversion engineering
conference 2 1986 791-797
[38] IK Garkushin AC Trunin TT Miftakhov and MA Dibirov Salt heat storage
composition USSR Patent 1036734 1983
[39] W M Philips and J W Stears Advanced latent heat of fusion thermal energy storage for
solar power stations In Proceedings of 20th intersociety energy conversion engineering
conference 2 1985 384-391
[40] Y Takahashi M Kamimoto Y Abe R Sakamoto K Kanari and T Ozawa Investigation
of latent heat-thermal energy storage materials IV Thermoanalitical evaluation of binary eutectic
mixtures of NaOH with LiOH or KOH Thermochim Acta 121 1987 193-202
[41] C E Birchenall and A F Riechman Heat storage in eutectic alloys Metall Trans A
11A(8) 1980 1415-1420
100
[42] Y Takahashi R Sakamoto and M Kamimoto Heat capacities and latent heats of LiNO3
NaNO3 and KNO3 International Journal of Thermophysics 9(6) 1988 1081-1090
[43] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate Mixtures
Journal of Chemical Engineering Data 8(3) 1963 469
[44] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical Engineering Data 6 (4) 1961 493
[45] GF Petersen WA Ewing and G P Smith Densities of Some Salt Mixtures Journal of
Chemical Engineering Data 6 (4) 1961 540
[46] G J Janz and M R Lorenz Precise Measurement of Density and Surface Tension at
Temperatures up to 1000degC in One Apparatus Review of Scientific Instruments 31 (1) 1960
18-23
[47] G J Janz C B Allen N P Bansal R M Murphy and R P Tomkins Physical Properties
Data Compilations Relevant to Energy Storage II Molten Salts Data on Single and Multi-
Component Salt Systems National Bureau of Standards NSRDS-NBS 61 Part II April 1979
[48] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation Equations
for Critically Evaluated Density Surface Tension Electrical Conductance and Viscosity Data
Journal of Physical and Chemical Reference Data 17 1988 2
[49] A T Ward and G J Janz Molten Carbonate Electrolytes Electiral Conductance Density
and Surface Tension of Binary and Ternary Eleclrochimica Acta 10 1965 849-857
[50] Y Takahashi R Sakamoto and MKamimoto Heat Capacities and Latent Heat of LiNO3
NaNO3 amp KNO3 International Journal of Thermophysics 9 1998 1081-1090
[51] R W Carling Heat capacities of NaNO3 and KNO3 up to 800 K Thermochimica Acta 60
1983 265-275
[52] Y Takahashi Latent heat measurement by DSC with sapphire as standard material
Thermochim Acta 88(1) 1985 199-204
101
[53] GW Hohne W Hemminger and HJ Flammersheim Differential Scanning Calorimetry
Springer-Verlag Berlin 1996
[54] W Hemminger and G Hohne Calorimetry Fundamentals and Practice Verlag Weinheim
1984
[55] M Merzlyakov and C Schick Thermal conductivity from dynamic response of DSC
Thermochimica Acta 377 2001 183-191
[56] T Kousksou A Jamil S Gibout and Y Zeraouli Thermal analysis of phase change
emulsion Journal of Thermal Analysis and Calorimetry 96 2009 841-852
[57] A Jamil T Kousksou K El Omari Y Zeraouli and Y Le Guer Heat transfer in salt
solutions enclosed in DSC cells Thermochimica Acta 507-508 2010 15-20
[58] MJ Richardson Quantitative aspects of differential scanning calorimetry Thermochimica
Acta 300 1997 15-28
[59] S Rudtsch Uncertainty of heat capacity measurements with differential scanning
calorimeters Thermochimica Acta 382 2002 17-25
[60] M J Maeso and J Largo The phase diagram of LiNO3-NaNO3 and LiNO3-KNO3 the
behavior of liquid mixtures Thermochimica Acta 223 (1993) 145-156
[61] O J Kleppa A new twin high-temperature reaction calorimeter The heats of mixing in
liquid sodium-potassium nitrates Journal of Physical Chemistry 64(12) (1960) 1937-1940
[62] G W H Hhne H K Cammenga W Eysel E Gmelin and W Hemminger The
Temperature Calibration of Scanning Calorimeters Thermochimica Acta 160 1990 1-12
[63] L B Pankratz Thermodynamic Properties of Carbides Nitrides and Other Selected
Substances U S Bureau of Mines Bulletin 696 1994
[64] M Zhang and R G Reddy Thermodynamic properties of C4mim[Tf2N] ionic liquids 0 2
2010 71-76
102
[65] D Mantha T Wang and R G Reddy Thermodynamic Modeling of Eutectic Point in the
LiNO3-NaNO3-KNO3 Ternary System Journal of Phase Equilibria and Diffusion 2011
(accepted)
[66] R G Reddy T Wang and D Mantha Determination of thermodynamic properties of
2KNO3Mg(NO3)2 Thermochimica Acta 2011 (submitted)
[67] T Wang D Mantha and R G Reddy Thermal stability of new LiNO3-NaNO3-KNO3
ternary salt for thermal energy storage system (in preparation)
[68] G D Carvalho E Frollini and W N D Santos Thermal conductivity of polymers by hot-
wire method J Appl Poly Sci 62 (1996) 2281-2285
[69] H Bloom A Doroszkowski and S B Tricklebank Molten salt mixtures IX The thermal
conductivities of molten nitrate systems Aus J Chem 18(8) (1965) 1171-1176
[70] A G Turnbull Thermal conductivity of molten salts Aus J Appl Sci 12 (1961) 30-41
[71] L R White and H T Davis Thermal conductivity of molten alkali nitrates J Chem Phys
47(1967) 5433-5439
[72] M V Peralta-Martinez M J Assael M J Dix L Karagiannidis and W A Wakeham A
Novel Instrument for the Measurement of the Thermal Conductivity of Molten Metal Part1
Instrument‟s Description Int J Thermophysics 27 (2006) 353-375
[73] Y Tada M Harada M Tanlgakl and W Eguchl Laser Flash Method for Measuring
Thermal Conductivity of Liquids Application to Molten Salts Industrial and Engineering
Chemistry Fundamentals 20 1981 333- 336
[74] M V Smirnov V A Khokhlov and E S Filatov Thermal conductivity of molten alkali
halides and their mixtures Electrochimica Acta 32 (1986) 1019-1026
[75] E Marti E Kaisersberger and W D Emmerich NEW ASPECTS OF THERMAL
ANALYSIS Part I Resolution of DSC and means for its optimization Journal of Thermal
Analysis and Calorimetry 77 2004 905-934
103
[76] E Marti E Kaisersberger G Kaiser and WY Ma Netzsch Annual 2000
bdquoThermoanalytical Characterization of Pharmaceuticals‟ Netzsch-Geraumltebau GmbH D-95100
SelbBavaria
[77] P J van Ekeren C M Holl and A J Witteveen A comparative test of differential
scanning calorimeters Journal of Thermal Analysis and Calorimetry 49 1997 1105-1114
[78] G J Janz Thermodynamic and Transport Properties of Molten Salts Correlation
Equations for Critically Evaluated Density Surface Tension Electrical Conductance and
Viscosity Data Journal of Physical and Chemical Reference Data 17 1988 1
[79] G F Petersen W A Ewing and G P Smith ldquoDensities of Some Salt Mixturesrdquo Journal of
Chemical and Engineering Data 6 1961 540
[80] P M Nasch and S G Steinemann Density and Thermal Expansion of Molten Manganese
Iron Nickel Copper Aluminum and Tin by Means of the Gamma-Ray Attenuation Technique
Physics and Chemistry of Liquids 29 1995 43-58
[81] G P Smith and G F Petersen Volumetric Properties of the Molten System (LiK)-
(ClNO3) Journal of Chemical and Engineering Data 6 1961 493-496
[82] D A Nissen Thermophysical Properties of the Equimolar Mixture NaNO3-KNO3 from
300degC to 600degC Journal of Chemical and Engineering Data 27 1982 269-273
[83] D W James and C H Liu Densities of Some Molten Alkali Nitrate and Sulphate
Mixtures Journal of Chemical and Engineering Data 8 1963 469
104
APPENDIX
Appendix A
Table A1 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in solid state
(29815-40315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 342 1290 417 -025
299 027 008 000 343 1317 426 -026
300 059 018 000 344 1345 436 -027
301 091 028 000 345 1372 445 -028
302 123 037 000 346 1399 455 -029
303 154 047 000 347 1427 464 -031
304 186 056 000 348 1454 474 -032
305 217 066 000 349 1481 483 -033
306 248 076 000 350 1508 493 -035
307 279 085 000 351 1535 503 -036
308 310 095 -001 352 1562 512 -038
309 340 104 -001 353 1589 522 -039
310 371 114 -001 354 1616 532 -041
311 401 123 -001 355 1643 541 -042
312 432 133 -002 356 1670 551 -044
313 462 142 -002 357 1697 561 -045
314 492 152 -002 358 1724 570 -047
315 521 161 -003 359 1751 580 -048
316 551 171 -003 360 1777 590 -050
317 581 180 -004 361 1804 600 -052
318 610 190 -004 362 1831 610 -053
319 640 199 -005 363 1858 619 -055
320 669 209 -005 364 1885 629 -057
105
321 698 218 -006 365 1911 639 -059
322 727 228 -007 366 1938 649 -060
323 756 237 -007 367 1965 659 -062
324 785 246 -008 368 1992 669 -064
325 814 256 -009 369 2018 679 -066
326 842 265 -009 370 2045 689 -068
327 871 275 -010 371 2072 699 -070
328 899 284 -011 372 2098 709 -072
329 928 294 -012 373 2125 719 -074
330 956 303 -012 374 2152 729 -076
331 984 313 -013 375 2179 739 -078
332 1012 322 -014 376 2205 750 -080
333 1041 331 -015 377 2232 760 -082
334 1069 341 -016 378 2259 770 -084
335 1096 350 -017 379 2286 780 -086
336 1124 360 -018 380 2312 791 -088
337 1152 369 -019 381 2339 801 -090
338 1180 379 -020 382 2366 811 -093
339 1207 388 -021 383 2393 822 -095
340 1235 398 -022 384 2420 832 -097
341 1263 407 -023 38415 2424 834 -097
Table A2 Thermodynamic properties of LiNO3-KNO3-NaNO3 compound in liquid state
(40315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
40315 4287 1565 -163 514 7070 2838 -796
404 4310 1575 -167 515 7094 2850 -803
405 4337 1585 -171 516 7117 2863 -810
406 4363 1596 -175 517 7141 2875 -817
407 4390 1607 -180 518 7165 2887 -824
408 4417 1618 -184 519 7188 2899 -831
409 4443 1629 -189 520 7212 2911 -839
410 4470 1640 -193 521 7235 2924 -846
411 4496 1651 -197 522 7259 2936 -853
412 4523 1662 -202 523 7282 2948 -860
106
413 4549 1672 -206 524 7306 2960 -868
414 4576 1683 -211 525 7329 2973 -875
415 4602 1694 -216 526 7352 2985 -882
416 4629 1705 -220 527 7376 2997 -890
417 4655 1716 -225 528 7399 3010 -897
418 4681 1727 -230 529 7422 3022 -904
419 4708 1738 -234 530 7446 3034 -912
420 4734 1749 -239 531 7469 3047 -919
421 4760 1760 -244 532 7492 3059 -927
422 4786 1771 -249 533 7516 3071 -934
423 4813 1782 -253 534 7539 3084 -942
424 4839 1793 -258 535 7562 3096 -949
425 4865 1804 -263 536 7585 3109 -957
426 4891 1816 -268 537 7608 3121 -965
427 4917 1827 -273 538 7632 3134 -972
428 4943 1838 -278 539 7655 3146 -980
429 4969 1849 -283 540 7678 3158 -988
430 4995 1860 -288 541 7701 3171 -995
431 5021 1871 -293 542 7724 3183 -1003
432 5046 1882 -298 543 7747 3196 -1011
433 5072 1894 -303 544 7770 3208 -1018
434 5098 1905 -308 545 7793 3221 -1026
435 5124 1916 -313 546 7816 3233 -1034
436 5149 1927 -318 547 7839 3246 -1042
437 5175 1938 -323 548 7862 3259 -1050
438 5201 1950 -328 549 7885 3271 -1058
439 5226 1961 -334 550 7908 3284 -1066
440 5252 1972 -339 551 7931 3296 -1073
441 5278 1983 -344 552 7953 3309 -1081
442 5303 1995 -349 553 7976 3322 -1089
443 5329 2006 -355 554 7999 3334 -1097
444 5354 2017 -360 555 8022 3347 -1105
445 5380 2028 -365 556 8045 3359 -1113
446 5405 2040 -371 557 8067 3372 -1121
447 5430 2051 -376 558 8090 3385 -1130
448 5456 2062 -382 559 8113 3398 -1138
449 5481 2074 -387 560 8136 3410 -1146
450 5506 2085 -393 561 8158 3423 -1154
451 5532 2097 -398 562 8181 3436 -1162
452 5557 2108 -404 563 8204 3448 -1170
107
453 5582 2119 -409 564 8226 3461 -1178
454 5607 2131 -415 565 8249 3474 -1187
455 5633 2142 -421 566 8271 3487 -1195
456 5658 2154 -426 567 8294 3499 -1203
457 5683 2165 -432 568 8317 3512 -1212
458 5708 2177 -438 569 8339 3525 -1220
459 5733 2188 -443 570 8362 3538 -1228
460 5758 2200 -449 571 8384 3551 -1237
461 5783 2211 -455 572 8407 3564 -1245
462 5808 2223 -461 573 8429 3576 -1253
463 5833 2234 -466 574 8452 3589 -1262
464 5858 2246 -472 575 8474 3602 -1270
465 5883 2257 -478 576 8496 3615 -1279
466 5907 2269 -484 577 8519 3628 -1287
467 5932 2280 -490 578 8541 3641 -1296
468 5957 2292 -496 579 8564 3654 -1304
469 5982 2304 -502 580 8586 3667 -1313
470 6007 2315 -508 581 8608 3680 -1322
471 6031 2327 -514 582 8631 3693 -1330
472 6056 2339 -520 583 8653 3706 -1339
473 6081 2350 -526 584 8675 3719 -1348
474 6105 2362 -532 585 8697 3732 -1356
475 6130 2373 -538 586 8720 3745 -1365
476 6155 2385 -544 587 8742 3758 -1374
477 6179 2397 -551 588 8764 3771 -1382
478 6204 2409 -557 589 8786 3784 -1391
479 6228 2420 -563 590 8808 3797 -1400
480 6253 2432 -569 591 8831 3810 -1409
481 6277 2444 -575 592 8853 3823 -1418
482 6301 2456 -582 593 8875 3836 -1426
483 6326 2467 -588 594 8897 3849 -1435
484 6350 2479 -594 595 8919 3863 -1444
485 6375 2491 -601 596 8941 3876 -1453
486 6399 2503 -607 597 8963 3889 -1462
487 6423 2515 -614 598 8985 3902 -1471
488 6448 2526 -620 599 9007 3915 -1480
489 6472 2538 -626 600 9029 3928 -1489
490 6496 2550 -633 601 9051 3942 -1498
491 6520 2562 -639 602 9073 3955 -1507
492 6544 2574 -646 603 9095 3968 -1516
108
493 6569 2586 -653 604 9117 3981 -1525
494 6593 2598 -659 605 9139 3994 -1535
495 6617 2610 -666 606 9161 4008 -1544
496 6641 2621 -672 607 9183 4021 -1553
497 6665 2633 -679 608 9205 4034 -1562
498 6689 2645 -686 609 9226 4048 -1571
499 6713 2657 -692 610 9248 4061 -1581
500 6737 2669 -699 611 9270 4074 -1590
501 6761 2681 -706 612 9292 4088 -1599
502 6785 2693 -713 613 9314 4101 -1608
503 6809 2705 -719 614 9335 4114 -1618
504 6833 2717 -726 615 9357 4128 -1627
505 6856 2729 -733 616 9379 4141 -1636
506 6880 2741 -740 617 9401 4154 -1646
507 6904 2754 -747 618 9422 4168 -1655
508 6928 2766 -754 619 9444 4181 -1665
509 6952 2778 -761 620 9466 4195 -1674
510 6975 2790 -768 621 9487 4208 -1684
511 6999 2802 -775 622 9509 4222 -1693
512 7023 2814 -782 623 9531 4235 -1703
513 7047 2826 -789 62315 9534 4237 -1704
109
Appendix B
Table B1 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(29815-39215K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 347 1233 382 -046
299 022 006 000 348 1258 390 -048
300 049 014 -001 349 1283 398 -049
301 075 022 -001 350 1307 406 -051
302 101 029 -001 351 1332 415 -053
303 127 037 -002 352 1356 423 -054
304 153 044 -002 353 1381 431 -056
305 179 052 -003 354 1405 440 -058
306 205 059 -003 355 1430 448 -060
307 230 067 -004 356 1455 456 -061
308 256 075 -004 357 1479 465 -063
309 282 082 -005 358 1504 473 -065
310 308 090 -005 359 1528 482 -067
311 333 098 -006 360 1553 490 -069
312 359 105 -007 361 1577 498 -071
313 384 113 -007 362 1602 507 -073
314 410 121 -008 363 1626 515 -075
315 435 128 -009 364 1651 524 -077
316 461 136 -010 365 1675 533 -079
317 486 144 -010 366 1700 541 -081
318 511 151 -011 367 1724 550 -083
319 537 159 -012 368 1749 558 -085
320 562 167 -013 369 1773 567 -087
321 587 175 -014 370 1798 576 -089
322 612 182 -015 371 1822 584 -092
323 637 190 -016 372 1847 593 -094
324 663 198 -017 373 1871 602 -096
325 688 206 -018 374 1896 611 -098
326 713 214 -019 375 1920 620 -100
327 738 222 -020 376 1945 628 -103
328 763 229 -021 377 1969 637 -105
329 788 237 -022 378 1994 646 -107
110
330 813 245 -023 379 2018 655 -110
331 838 253 -024 380 2043 664 -112
332 863 261 -025 381 2068 673 -115
333 887 269 -027 382 2092 682 -117
334 912 277 -028 383 2117 691 -120
335 937 285 -029 384 2141 700 -122
336 962 293 -030 385 2166 709 -125
337 987 301 -032 386 2191 718 -127
338 1011 309 -033 387 2215 727 -130
339 1036 317 -034 388 2240 737 -132
340 1061 325 -036 389 2265 746 -135
341 1086 333 -037 390 2289 755 -138
342 1110 341 -039 391 2314 764 -140
343 1135 349 -040 392 2339 774 -143
344 1160 357 -042 39215 2342 775 -144
345 1184 365 -043
Table B2 Thermodynamic properties of NaNO3-NaNO2-NaNO3 compound in liquid state
(41315-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
414 3280 1149 -209 520 5608 2235 -682
415 3302 1158 -212 521 5630 2246 -687
416 3325 1167 -216 522 5651 2257 -693
417 3348 1177 -219 523 5672 2268 -698
418 3370 1186 -223 524 5694 2279 -704
419 3393 1196 -226 525 5715 2290 -710
420 3416 1205 -229 526 5736 2302 -716
421 3438 1215 -233 527 5757 2313 -721
422 3461 1224 -236 528 5779 2324 -727
423 3483 1234 -240 529 5800 2335 -733
424 3506 1243 -243 530 5821 2347 -739
425 3529 1253 -247 531 5842 2358 -745
426 3551 1263 -250 532 5864 2369 -750
427 3574 1272 -254 533 5885 2380 -756
428 3596 1282 -257 534 5906 2392 -762
429 3619 1291 -261 535 5927 2403 -768
111
430 3641 1301 -265 536 5948 2414 -774
431 3663 1311 -268 537 5970 2426 -780
432 3686 1320 -272 538 5991 2437 -786
433 3708 1330 -276 539 6012 2449 -792
434 3731 1340 -279 540 6033 2460 -798
435 3753 1350 -283 541 6054 2471 -804
436 3775 1359 -287 542 6075 2483 -810
437 3798 1369 -291 543 6096 2494 -816
438 3820 1379 -294 544 6118 2506 -822
439 3842 1389 -298 545 6139 2517 -828
440 3865 1398 -302 546 6160 2529 -835
441 3887 1408 -306 547 6181 2540 -841
442 3909 1418 -310 548 6202 2552 -847
443 3932 1428 -314 549 6223 2563 -853
444 3954 1438 -318 550 6244 2575 -859
445 3976 1448 -322 551 6265 2586 -866
446 3998 1458 -326 552 6286 2598 -872
447 4021 1468 -330 553 6307 2610 -878
448 4043 1477 -334 554 6328 2621 -884
449 4065 1487 -338 555 6349 2633 -891
450 4087 1497 -342 556 6370 2645 -897
451 4109 1507 -346 557 6391 2656 -904
452 4131 1517 -350 558 6412 2668 -910
453 4154 1527 -354 559 6433 2680 -916
454 4176 1537 -358 560 6454 2691 -923
455 4198 1547 -363 561 6475 2703 -929
456 4220 1557 -367 562 6496 2715 -936
457 4242 1568 -371 563 6517 2727 -942
458 4264 1578 -375 564 6538 2738 -949
459 4286 1588 -380 565 6559 2750 -955
460 4308 1598 -384 566 6580 2762 -962
461 4330 1608 -388 567 6600 2774 -969
462 4352 1618 -393 568 6621 2786 -975
463 4374 1628 -397 569 6642 2798 -982
464 4396 1639 -401 570 6663 2810 -988
465 4418 1649 -406 571 6684 2821 -995
466 4440 1659 -410 572 6705 2833 -1002
467 4462 1669 -415 573 6726 2845 -1009
468 4484 1680 -419 574 6747 2857 -1015
469 4506 1690 -424 575 6767 2869 -1022
112
470 4528 1700 -428 576 6788 2881 -1029
471 4550 1710 -433 577 6809 2893 -1036
472 4572 1721 -437 578 6830 2905 -1042
473 4593 1731 -442 579 6851 2917 -1049
474 4615 1741 -446 580 6871 2929 -1056
475 4637 1752 -451 581 6892 2941 -1063
476 4659 1762 -456 582 6913 2953 -1070
477 4681 1773 -460 583 6934 2966 -1077
478 4703 1783 -465 584 6954 2978 -1084
479 4724 1793 -470 585 6975 2990 -1091
480 4746 1804 -474 586 6996 3002 -1098
481 4768 1814 -479 587 7017 3014 -1105
482 4790 1825 -484 588 7037 3026 -1112
483 4812 1835 -489 589 7058 3038 -1119
484 4833 1846 -494 590 7079 3051 -1126
485 4855 1856 -498 591 7100 3063 -1133
486 4877 1867 -503 592 7120 3075 -1140
487 4898 1877 -508 593 7141 3087 -1147
488 4920 1888 -513 594 7162 3100 -1154
489 4942 1899 -518 595 7182 3112 -1162
490 4963 1909 -523 596 7203 3124 -1169
491 4985 1920 -528 597 7224 3137 -1176
492 5007 1930 -533 598 7244 3149 -1183
493 5028 1941 -538 599 7265 3161 -1190
494 5050 1952 -543 600 7285 3174 -1198
495 5072 1962 -548 601 7306 3186 -1205
496 5093 1973 -553 602 7327 3198 -1212
497 5115 1984 -558 603 7347 3211 -1220
498 5136 1995 -563 604 7368 3223 -1227
499 5158 2005 -568 605 7389 3236 -1234
500 5180 2016 -574 606 7409 3248 -1242
501 5201 2027 -579 607 7430 3261 -1249
502 5223 2038 -584 608 7450 3273 -1257
503 5244 2049 -589 609 7471 3286 -1264
504 5266 2059 -595 610 7491 3298 -1272
505 5287 2070 -600 611 7512 3311 -1279
506 5309 2081 -605 612 7532 3323 -1287
507 5330 2092 -610 613 7553 3336 -1294
508 5352 2103 -616 614 7573 3348 -1302
509 5373 2114 -621 615 7594 3361 -1309
113
510 5394 2125 -627 616 7615 3374 -1317
511 5416 2136 -632 617 7635 3386 -1325
512 5437 2147 -637 618 7656 3399 -1332
513 5459 2158 -643 619 7676 3412 -1340
514 5480 2169 -648 620 7696 3424 -1348
515 5502 2180 -654 621 7717 3437 -1355
516 5523 2191 -659 622 7737 3450 -1363
517 5544 2202 -665 623 7758 3462 -1371
518 5566 2213 -670 62315 7761 3464 -1372
114
Appendix C
Table C1 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in solid
state (29815-36415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 333 1937 611 -034
299 048 014 000 334 1992 629 -036
300 104 031 000 335 2047 647 -038
301 160 048 000 336 2102 666 -040
302 216 065 000 337 2156 684 -042
303 272 082 -001 338 2211 703 -045
304 329 099 -001 339 2266 721 -047
305 385 116 -001 340 2321 740 -049
306 441 133 -002 341 2375 758 -052
307 496 150 -002 342 2430 777 -054
308 552 167 -003 343 2485 796 -056
309 608 185 -003 344 2539 815 -059
310 664 202 -004 345 2594 833 -062
311 720 219 -005 346 2648 852 -064
312 776 236 -006 347 2703 871 -067
313 831 254 -006 348 2757 890 -070
314 887 271 -007 349 2812 909 -072
315 942 289 -008 350 2866 928 -075
316 998 306 -009 351 2921 947 -078
317 1054 324 -010 352 2975 966 -081
318 1109 341 -011 353 3029 985 -084
319 1164 359 -012 354 3084 1004 -087
320 1220 377 -014 355 3138 1024 -090
321 1275 395 -015 356 3192 1043 -094
322 1331 412 -016 357 3246 1062 -097
323 1386 430 -018 358 3300 1082 -100
324 1441 448 -019 359 3355 1101 -103
325 1496 466 -020 360 3409 1120 -107
326 1552 484 -022 361 3463 1140 -110
327 1607 502 -024 362 3517 1159 -114
328 1662 520 -025 363 3571 1179 -117
329 1717 538 -027 364 3625 1199 -121
115
330 1772 556 -029 36415 3633 1202 -121
331 1827 574 -030
332 1882 593 -032
Table C2 Thermodynamic properties of LiNO3-NaNO3-KNO3-MgK compound in liquid
state (42115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
42115 7428 2673 -455 523 11788 4725 -1440
422 7468 2690 -461 524 11827 4745 -1452
423 7515 2710 -468 525 11866 4766 -1464
424 7562 2730 -476 526 11904 4786 -1476
425 7608 2750 -484 527 11943 4807 -1488
426 7655 2770 -491 528 11982 4827 -1500
427 7702 2790 -499 529 12021 4847 -1512
428 7748 2810 -507 530 12059 4868 -1524
429 7795 2830 -514 531 12098 4888 -1536
430 7841 2849 -522 532 12137 4909 -1548
431 7887 2869 -530 533 12175 4929 -1560
432 7933 2889 -538 534 12213 4950 -1572
433 7979 2909 -546 535 12252 4970 -1584
434 8025 2929 -554 536 12290 4991 -1597
435 8071 2949 -562 537 12328 5011 -1609
436 8117 2969 -570 538 12366 5032 -1621
437 8163 2989 -578 539 12404 5052 -1634
438 8208 3009 -586 540 12442 5073 -1646
439 8254 3029 -595 541 12480 5093 -1659
440 8299 3049 -603 542 12518 5114 -1671
441 8345 3069 -611 543 12556 5134 -1684
442 8390 3089 -620 544 12594 5155 -1696
443 8435 3109 -628 545 12632 5175 -1709
444 8480 3129 -636 546 12669 5196 -1721
445 8525 3149 -645 547 12707 5217 -1734
446 8570 3169 -654 548 12745 5237 -1747
116
447 8615 3189 -662 549 12782 5258 -1760
448 8659 3209 -671 550 12820 5278 -1772
449 8704 3229 -679 551 12857 5299 -1785
450 8748 3249 -688 552 12894 5319 -1798
451 8793 3269 -697 553 12932 5340 -1811
452 8837 3289 -706 554 12969 5361 -1824
453 8881 3309 -715 555 13006 5381 -1837
454 8926 3329 -724 556 13043 5402 -1850
455 8970 3349 -732 557 13080 5422 -1863
456 9014 3369 -741 558 13117 5443 -1876
457 9058 3389 -750 559 13154 5464 -1889
458 9102 3409 -760 560 13191 5484 -1902
459 9145 3429 -769 561 13228 5505 -1916
460 9189 3449 -778 562 13264 5526 -1929
461 9233 3469 -787 563 13301 5546 -1942
462 9276 3489 -796 564 13338 5567 -1956
463 9319 3509 -806 565 13374 5588 -1969
464 9363 3529 -815 566 13411 5608 -1982
465 9406 3549 -824 567 13447 5629 -1996
466 9449 3570 -834 568 13484 5650 -2009
467 9492 3590 -843 569 13520 5670 -2023
468 9535 3610 -853 570 13557 5691 -2036
469 9578 3630 -862 571 13593 5712 -2050
470 9621 3650 -872 572 13629 5732 -2063
471 9664 3670 -882 573 13665 5753 -2077
472 9707 3690 -891 574 13701 5774 -2091
473 9749 3710 -901 575 13737 5795 -2104
474 9792 3731 -911 576 13773 5815 -2118
475 9834 3751 -921 577 13809 5836 -2132
476 9877 3771 -930 578 13845 5857 -2146
477 9919 3791 -940 579 13881 5877 -2160
478 9961 3811 -950 580 13917 5898 -2174
479 10004 3831 -960 581 13953 5919 -2188
480 10046 3852 -970 582 13988 5940 -2202
481 10088 3872 -980 583 14024 5960 -2216
482 10130 3892 -990 584 14060 5981 -2230
483 10171 3912 -1001 585 14095 6002 -2244
484 10213 3932 -1011 586 14131 6023 -2258
485 10255 3953 -1021 587 14166 6044 -2272
486 10297 3973 -1031 588 14201 6064 -2286
117
487 10338 3993 -1042 589 14237 6085 -2300
488 10380 4013 -1052 590 14272 6106 -2315
489 10421 4034 -1062 591 14307 6127 -2329
490 10462 4054 -1073 592 14342 6148 -2343
491 10504 4074 -1083 593 14378 6168 -2358
492 10545 4094 -1094 594 14413 6189 -2372
493 10586 4114 -1104 595 14448 6210 -2386
494 10627 4135 -1115 596 14483 6231 -2401
495 10668 4155 -1126 597 14518 6252 -2415
496 10709 4175 -1136 598 14552 6273 -2430
497 10750 4196 -1147 599 14587 6293 -2444
498 10791 4216 -1158 600 14622 6314 -2459
499 10831 4236 -1169 601 14657 6335 -2474
500 10872 4256 -1179 602 14692 6356 -2488
501 10912 4277 -1190 603 14726 6377 -2503
502 10953 4297 -1201 604 14761 6398 -2518
503 10993 4317 -1212 605 14795 6419 -2533
504 11034 4338 -1223 606 14830 6439 -2547
505 11074 4358 -1234 607 14864 6460 -2562
506 11114 4378 -1245 608 14899 6481 -2577
507 11154 4399 -1257 609 14933 6502 -2592
508 11194 4419 -1268 610 14967 6523 -2607
509 11234 4439 -1279 611 15002 6544 -2622
510 11274 4460 -1290 612 15036 6565 -2637
511 11314 4480 -1302 613 15070 6586 -2652
512 11354 4500 -1313 614 15104 6607 -2667
513 11394 4521 -1324 615 15138 6628 -2682
514 11433 4541 -1336 616 15172 6649 -2697
515 11473 4562 -1347 617 15206 6670 -2713
516 11513 4582 -1359 618 15240 6691 -2728
517 11552 4602 -1370 619 15274 6712 -2743
518 11591 4623 -1382 620 15308 6733 -2758
519 11631 4643 -1393 621 15342 6754 -2774
520 11670 4664 -1405 622 15375 6774 -2789
521 11709 4684 -1417 623 15409 6795 -2804
522 11748 4704 -1428 62315 15414 6799 -2807
118
Appendix D
Table D1 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in solid state
(29815-36315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
299 021 006 000 333 867 277 -012
300 047 014 000 334 891 285 -012
301 072 022 000 335 916 293 -013
302 097 029 000 336 940 302 -014
303 122 037 000 337 964 310 -015
304 147 045 000 338 989 318 -016
305 172 053 000 339 1013 327 -017
306 197 060 000 340 1037 335 -018
307 223 068 000 341 1061 343 -019
308 248 076 000 342 1085 352 -019
309 273 084 000 343 1109 360 -020
310 298 092 -001 344 1134 369 -021
311 323 099 -001 345 1158 377 -022
312 348 107 -001 346 1182 385 -024
313 373 115 -001 347 1206 394 -025
314 398 123 -002 348 1230 402 -026
315 423 131 -002 349 1254 411 -027
316 447 139 -002 350 1277 419 -028
317 472 147 -003 351 1301 428 -029
318 497 155 -003 352 1325 436 -030
319 522 163 -003 353 1349 445 -032
320 547 171 -004 354 1373 453 -033
321 572 179 -004 355 1396 462 -034
322 596 187 -005 356 1420 470 -035
323 621 195 -005 357 1444 479 -037
324 646 203 -006 358 1467 487 -038
325 670 211 -006 359 1491 496 -039
326 695 220 -007 360 1514 504 -041
327 720 228 -008 361 1538 513 -042
328 744 236 -008 362 1561 522 -043
329 769 244 -009 363 1584 530 -045
330 793 252 -010 36315 1588 532 -045
119
331 818 260 -010
Table D2 Thermodynamic properties of LiNO3-NaNO3-KNO3-NaNO2 compound in liquid
state (38115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
38115 2281 765 -104 503 5639 2242 -594
382 2307 775 -106 504 5664 2255 -600
383 2338 787 -109 505 5689 2267 -606
384 2369 798 -111 506 5713 2280 -611
385 2399 810 -113 507 5738 2292 -617
386 2430 822 -116 508 5763 2305 -623
387 2460 834 -118 509 5787 2317 -629
388 2491 846 -121 510 5812 2330 -634
389 2521 857 -123 511 5836 2342 -640
390 2551 869 -126 512 5861 2355 -646
391 2582 881 -128 513 5885 2367 -652
392 2612 893 -131 514 5910 2380 -658
393 2642 905 -134 515 5934 2392 -664
394 2672 917 -136 516 5959 2405 -670
395 2702 928 -139 517 5983 2417 -676
396 2732 940 -142 518 6007 2430 -682
397 2762 952 -144 519 6032 2443 -688
398 2792 964 -147 520 6056 2455 -694
399 2821 976 -150 521 6080 2468 -700
400 2851 988 -153 522 6104 2480 -706
401 2881 999 -156 523 6128 2493 -712
402 2910 1011 -159 524 6152 2506 -718
403 2940 1023 -162 525 6176 2518 -724
404 2969 1035 -164 526 6200 2531 -731
405 2999 1047 -167 527 6224 2544 -737
406 3028 1059 -170 528 6248 2556 -743
407 3057 1071 -174 529 6272 2569 -749
408 3087 1083 -177 530 6296 2581 -756
120
409 3116 1095 -180 531 6320 2594 -762
410 3145 1107 -183 532 6344 2607 -768
411 3174 1119 -186 533 6368 2619 -775
412 3203 1130 -189 534 6391 2632 -781
413 3232 1142 -192 535 6415 2645 -787
414 3261 1154 -196 536 6439 2657 -794
415 3290 1166 -199 537 6462 2670 -800
416 3319 1178 -202 538 6486 2683 -807
417 3347 1190 -206 539 6510 2696 -813
418 3376 1202 -209 540 6533 2708 -820
419 3405 1214 -212 541 6557 2721 -826
420 3433 1226 -216 542 6580 2734 -833
421 3462 1238 -219 543 6604 2746 -839
422 3490 1250 -223 544 6627 2759 -846
423 3519 1262 -226 545 6650 2772 -853
424 3547 1274 -230 546 6674 2785 -859
425 3575 1286 -233 547 6697 2797 -866
426 3604 1298 -237 548 6720 2810 -873
427 3632 1310 -240 549 6744 2823 -879
428 3660 1322 -244 550 6767 2836 -886
429 3688 1334 -248 551 6790 2848 -893
430 3716 1346 -251 552 6813 2861 -900
431 3744 1358 -255 553 6836 2874 -907
432 3772 1371 -259 554 6860 2887 -913
433 3800 1383 -263 555 6883 2900 -920
434 3828 1395 -267 556 6906 2912 -927
435 3856 1407 -270 557 6929 2925 -934
436 3883 1419 -274 558 6952 2938 -941
437 3911 1431 -278 559 6975 2951 -948
438 3939 1443 -282 560 6998 2964 -955
439 3966 1455 -286 561 7020 2976 -962
440 3994 1467 -290 562 7043 2989 -969
441 4021 1479 -294 563 7066 3002 -976
442 4049 1491 -298 564 7089 3015 -983
443 4076 1504 -302 565 7112 3028 -990
444 4103 1516 -306 566 7134 3041 -997
445 4131 1528 -310 567 7157 3054 -1005
446 4158 1540 -314 568 7180 3066 -1012
447 4185 1552 -319 569 7203 3079 -1019
448 4212 1564 -323 570 7225 3092 -1026
121
449 4240 1576 -327 571 7248 3105 -1033
450 4267 1589 -331 572 7270 3118 -1041
451 4294 1601 -336 573 7293 3131 -1048
452 4321 1613 -340 574 7315 3144 -1055
453 4347 1625 -344 575 7338 3157 -1063
454 4374 1637 -349 576 7360 3170 -1070
455 4401 1650 -353 577 7383 3183 -1077
456 4428 1662 -357 578 7405 3196 -1085
457 4455 1674 -362 579 7428 3208 -1092
458 4481 1686 -366 580 7450 3221 -1100
459 4508 1698 -371 581 7472 3234 -1107
460 4535 1711 -375 582 7494 3247 -1114
461 4561 1723 -380 583 7517 3260 -1122
462 4588 1735 -384 584 7539 3273 -1129
463 4614 1747 -389 585 7561 3286 -1137
464 4641 1760 -394 586 7583 3299 -1145
465 4667 1772 -398 587 7605 3312 -1152
466 4693 1784 -403 588 7628 3325 -1160
467 4720 1796 -408 589 7650 3338 -1167
468 4746 1809 -412 590 7672 3351 -1175
469 4772 1821 -417 591 7694 3364 -1183
470 4798 1833 -422 592 7716 3377 -1191
471 4825 1846 -427 593 7738 3390 -1198
472 4851 1858 -432 594 7760 3403 -1206
473 4877 1870 -437 595 7782 3416 -1214
474 4903 1882 -441 596 7804 3429 -1222
475 4929 1895 -446 597 7825 3442 -1229
476 4955 1907 -451 598 7847 3455 -1237
477 4980 1919 -456 599 7869 3469 -1245
478 5006 1932 -461 600 7891 3482 -1253
479 5032 1944 -466 601 7913 3495 -1261
480 5058 1956 -471 602 7934 3508 -1269
481 5083 1969 -476 603 7956 3521 -1277
482 5109 1981 -481 604 7978 3534 -1285
483 5135 1994 -487 605 8000 3547 -1293
484 5160 2006 -492 606 8021 3560 -1301
485 5186 2018 -497 607 8043 3573 -1309
486 5211 2031 -502 608 8064 3586 -1317
487 5237 2043 -507 609 8086 3599 -1325
488 5262 2055 -513 610 8107 3613 -1333
122
489 5288 2068 -518 611 8129 3626 -1341
490 5313 2080 -523 612 8150 3639 -1349
491 5338 2093 -528 613 8172 3652 -1357
492 5364 2105 -534 614 8193 3665 -1366
493 5389 2117 -539 615 8215 3678 -1374
494 5414 2130 -545 616 8236 3692 -1382
495 5439 2142 -550 617 8258 3705 -1390
496 5464 2155 -555 618 8279 3718 -1398
497 5489 2167 -561 619 8300 3731 -1407
498 5514 2180 -566 620 8321 3744 -1415
499 5539 2192 -572 621 8343 3757 -1423
500 5564 2205 -578 622 8364 3771 -1432
501 5589 2217 -583 623 8385 3784 -1441
502 5614 2230 -589 62315 8388 3786 -1443
123
Appendix E
Table E1 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in solid state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 913 287 -014
299 025 007 000 331 941 296 -015
300 054 016 000 332 970 306 -016
301 083 025 000 333 998 315 -017
302 112 034 000 334 1026 324 -018
303 141 042 000 335 1054 334 -019
304 170 051 000 336 1081 343 -020
305 199 060 -001 337 1109 353 -021
306 228 069 -001 338 1137 362 -022
307 257 078 -001 339 1165 371 -024
308 286 087 -001 340 1193 381 -025
309 315 096 -002 341 1221 390 -026
310 343 105 -002 342 1248 400 -027
311 372 113 -002 343 1276 409 -028
312 401 122 -003 344 1304 419 -030
313 430 131 -003 345 1331 428 -031
314 458 140 -003 346 1359 438 -032
315 487 149 -004 347 1386 447 -034
316 516 159 -004 348 1414 457 -035
317 544 168 -005 349 1441 466 -036
318 573 177 -006 350 1468 476 -038
319 602 186 -006 351 1496 486 -039
320 630 195 -007 352 1523 495 -041
321 659 204 -007 353 1550 505 -042
322 687 213 -008 354 1577 514 -044
323 715 222 -009 355 1605 524 -046
324 744 232 -009 356 1632 534 -047
325 772 241 -010 357 1659 543 -049
326 800 250 -011 358 1686 553 -050
327 829 259 -012 359 1713 563 -052
328 857 269 -013 35915 1717 564 -052
329 885 278 -013
124
Table E2 Thermodynamic properties of LiNO3-NaNO3-NaNO2-KNO3-KNO2 compound
in liquid state (376-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2323 777 -094 500 5525 2173 -590
376 2347 786 -096 501 5548 2184 -595
377 2375 797 -098 502 5572 2196 -601
378 2403 808 -101 503 5595 2208 -606
379 2431 818 -103 504 5619 2220 -612
380 2459 829 -106 505 5642 2232 -618
381 2487 839 -108 506 5665 2243 -623
382 2515 850 -111 507 5689 2255 -629
383 2542 861 -113 508 5712 2267 -635
384 2570 871 -116 509 5735 2279 -640
385 2598 882 -118 510 5759 2291 -646
386 2626 893 -121 511 5782 2303 -652
387 2653 903 -123 512 5805 2315 -658
388 2681 914 -126 513 5828 2326 -664
389 2708 925 -129 514 5852 2338 -669
390 2736 935 -132 515 5875 2350 -675
391 2763 946 -134 516 5898 2362 -681
392 2791 957 -137 517 5921 2374 -687
393 2818 968 -140 518 5944 2386 -693
394 2845 978 -143 519 5967 2398 -699
395 2873 989 -146 520 5990 2410 -705
396 2900 1000 -148 521 6013 2422 -711
397 2927 1011 -151 522 6036 2434 -717
398 2954 1022 -154 523 6059 2446 -723
399 2981 1032 -157 524 6082 2458 -729
400 3008 1043 -160 525 6105 2470 -735
401 3035 1054 -163 526 6128 2482 -741
402 3062 1065 -166 527 6151 2494 -747
403 3089 1076 -169 528 6173 2506 -754
404 3116 1086 -172 529 6196 2518 -760
405 3143 1097 -176 530 6219 2530 -766
125
406 3170 1108 -179 531 6242 2542 -772
407 3197 1119 -182 532 6265 2554 -778
408 3223 1130 -185 533 6287 2566 -785
409 3250 1141 -188 534 6310 2578 -791
410 3277 1152 -192 535 6333 2591 -797
411 3303 1163 -195 536 6355 2603 -804
412 3330 1174 -198 537 6378 2615 -810
413 3356 1185 -202 538 6400 2627 -816
414 3383 1195 -205 539 6423 2639 -823
415 3409 1206 -208 540 6445 2651 -829
416 3436 1217 -212 541 6468 2663 -836
417 3462 1228 -215 542 6490 2676 -842
418 3488 1239 -219 543 6513 2688 -849
419 3515 1250 -222 544 6535 2700 -855
420 3541 1261 -226 545 6558 2712 -862
421 3567 1272 -229 546 6580 2724 -868
422 3593 1283 -233 547 6602 2737 -875
423 3619 1294 -236 548 6625 2749 -882
424 3645 1305 -240 549 6647 2761 -888
425 3671 1317 -244 550 6669 2773 -895
426 3697 1328 -247 551 6692 2786 -902
427 3723 1339 -251 552 6714 2798 -908
428 3749 1350 -255 553 6736 2810 -915
429 3775 1361 -259 554 6758 2822 -922
430 3801 1372 -262 555 6780 2835 -929
431 3827 1383 -266 556 6803 2847 -935
432 3852 1394 -270 557 6825 2859 -942
433 3878 1405 -274 558 6847 2872 -949
434 3904 1416 -278 559 6869 2884 -956
435 3929 1428 -282 560 6891 2896 -963
436 3955 1439 -286 561 6913 2909 -970
437 3981 1450 -290 562 6935 2921 -977
438 4006 1461 -294 563 6957 2933 -983
439 4032 1472 -298 564 6979 2946 -990
440 4057 1483 -302 565 7001 2958 -997
441 4083 1495 -306 566 7023 2971 -1004
442 4108 1506 -310 567 7045 2983 -1011
443 4133 1517 -314 568 7067 2995 -1019
444 4159 1528 -318 569 7089 3008 -1026
445 4184 1540 -322 570 7110 3020 -1033
126
446 4209 1551 -327 571 7132 3033 -1040
447 4234 1562 -331 572 7154 3045 -1047
448 4260 1573 -335 573 7176 3058 -1054
449 4285 1585 -339 574 7198 3070 -1061
450 4310 1596 -344 575 7219 3083 -1069
451 4335 1607 -348 576 7241 3095 -1076
452 4360 1618 -352 577 7263 3108 -1083
453 4385 1630 -357 578 7284 3120 -1090
454 4410 1641 -361 579 7306 3133 -1098
455 4435 1652 -365 580 7328 3145 -1105
456 4460 1664 -370 581 7349 3158 -1112
457 4485 1675 -374 582 7371 3170 -1120
458 4510 1687 -379 583 7393 3183 -1127
459 4534 1698 -383 584 7414 3195 -1134
460 4559 1709 -388 585 7436 3208 -1142
461 4584 1721 -393 586 7457 3221 -1149
462 4609 1732 -397 587 7479 3233 -1157
463 4633 1743 -402 588 7500 3246 -1164
464 4658 1755 -406 589 7522 3258 -1172
465 4683 1766 -411 590 7543 3271 -1179
466 4707 1778 -416 591 7564 3284 -1187
467 4732 1789 -420 592 7586 3296 -1194
468 4756 1801 -425 593 7607 3309 -1202
469 4781 1812 -430 594 7628 3322 -1210
470 4805 1824 -435 595 7650 3334 -1217
471 4830 1835 -440 596 7671 3347 -1225
472 4854 1847 -444 597 7692 3360 -1233
473 4878 1858 -449 598 7714 3373 -1240
474 4903 1870 -454 599 7735 3385 -1248
475 4927 1881 -459 600 7756 3398 -1256
476 4951 1893 -464 601 7777 3411 -1264
477 4975 1904 -469 602 7799 3423 -1271
478 5000 1916 -474 603 7820 3436 -1279
479 5024 1927 -479 604 7841 3449 -1287
480 5048 1939 -484 605 7862 3462 -1295
481 5072 1951 -489 606 7883 3475 -1303
482 5096 1962 -494 607 7904 3487 -1311
483 5120 1974 -499 608 7925 3500 -1318
484 5144 1985 -504 609 7946 3513 -1326
485 5168 1997 -510 610 7967 3526 -1334
127
486 5192 2009 -515 611 7988 3539 -1342
487 5216 2020 -520 612 8009 3551 -1350
488 5240 2032 -525 613 8030 3564 -1358
489 5264 2044 -530 614 8051 3577 -1366
490 5288 2055 -536 615 8072 3590 -1374
491 5312 2067 -541 616 8093 3603 -1383
492 5335 2079 -546 617 8114 3616 -1391
493 5359 2090 -552 618 8135 3629 -1399
494 5383 2102 -557 619 8156 3642 -1407
495 5407 2114 -562 620 8177 3655 -1415
496 5430 2126 -568 621 8198 3667 -1423
497 5454 2137 -573 622 8219 3680 -1431
498 5478 2149 -579 623 8239 3693 -1440
499 5501 2161 -584 62315 8242 3695 -1441
128
Appendix F
Table F1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in solid
state (29815-35915K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 330 1063 334 -017
299 029 009 000 331 1096 345 -018
300 063 019 000 332 1128 356 -019
301 097 029 000 333 1161 366 -020
302 131 039 000 334 1193 377 -021
303 165 050 000 335 1225 388 -022
304 199 060 -001 336 1258 399 -024
305 233 070 -001 337 1290 410 -025
306 267 081 -001 338 1322 421 -026
307 300 091 -001 339 1355 432 -028
308 334 101 -002 340 1387 443 -029
309 368 112 -002 341 1419 454 -030
310 401 122 -002 342 1451 464 -032
311 435 133 -003 343 1483 475 -033
312 468 143 -003 344 1515 486 -035
313 502 153 -004 345 1547 497 -036
314 535 164 -004 346 1578 508 -038
315 569 174 -005 347 1610 519 -039
316 602 185 -005 348 1642 531 -041
317 635 196 -006 349 1674 542 -043
318 668 206 -006 350 1705 553 -044
319 702 217 -007 351 1737 564 -046
320 735 227 -008 352 1769 575 -048
321 768 238 -009 353 1800 586 -049
322 801 248 -009 354 1832 597 -051
323 834 259 -010 355 1863 608 -053
324 867 270 -011 356 1894 619 -055
325 900 280 -012 357 1926 631 -057
326 932 291 -013 358 1957 642 -059
327 965 302 -014 359 1988 653 -061
328 998 313 -015 35915 1993 655 -061
329 1030 323 -016
129
Table F2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-KNO2 compound in liquid
state (37515-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37515 2691 926 -083 500 6111 2416 -640
376 2717 936 -085 501 6136 2428 -646
377 2747 948 -088 502 6161 2440 -652
378 2778 959 -091 503 6185 2453 -658
379 2808 971 -094 504 6210 2465 -665
380 2838 982 -096 505 6235 2478 -671
381 2869 994 -099 506 6259 2490 -677
382 2899 1005 -102 507 6284 2502 -683
383 2929 1017 -105 508 6308 2515 -690
384 2959 1028 -108 509 6333 2527 -696
385 2989 1040 -111 510 6357 2540 -702
386 3019 1051 -114 511 6381 2552 -709
387 3049 1063 -117 512 6406 2565 -715
388 3079 1075 -120 513 6430 2577 -721
389 3109 1086 -123 514 6454 2590 -728
390 3138 1098 -126 515 6479 2602 -734
391 3168 1109 -129 516 6503 2615 -741
392 3198 1121 -133 517 6527 2627 -747
393 3227 1132 -136 518 6551 2640 -754
394 3257 1144 -139 519 6575 2652 -760
395 3286 1156 -142 520 6599 2665 -767
396 3316 1167 -146 521 6624 2677 -774
397 3345 1179 -149 522 6648 2690 -780
398 3374 1191 -152 523 6672 2702 -787
399 3403 1202 -156 524 6696 2715 -794
400 3433 1214 -159 525 6719 2727 -800
401 3462 1226 -163 526 6743 2740 -807
402 3491 1237 -166 527 6767 2753 -814
403 3520 1249 -170 528 6791 2765 -821
404 3549 1261 -173 529 6815 2778 -827
405 3578 1272 -177 530 6839 2790 -834
130
406 3606 1284 -180 531 6862 2803 -841
407 3635 1296 -184 532 6886 2815 -848
408 3664 1307 -187 533 6910 2828 -855
409 3693 1319 -191 534 6933 2841 -862
410 3721 1331 -195 535 6957 2853 -869
411 3750 1343 -199 536 6981 2866 -876
412 3778 1354 -202 537 7004 2879 -883
413 3807 1366 -206 538 7028 2891 -890
414 3835 1378 -210 539 7051 2904 -897
415 3864 1390 -214 540 7075 2917 -904
416 3892 1401 -218 541 7098 2929 -911
417 3920 1413 -222 542 7122 2942 -918
418 3948 1425 -226 543 7145 2955 -925
419 3977 1437 -230 544 7168 2967 -932
420 4005 1449 -234 545 7192 2980 -939
421 4033 1460 -238 546 7215 2993 -947
422 4061 1472 -242 547 7238 3005 -954
423 4089 1484 -246 548 7261 3018 -961
424 4117 1496 -250 549 7285 3031 -968
425 4145 1508 -254 550 7308 3044 -976
426 4172 1519 -258 551 7331 3056 -983
427 4200 1531 -262 552 7354 3069 -990
428 4228 1543 -266 553 7377 3082 -998
429 4256 1555 -271 554 7400 3095 -1005
430 4283 1567 -275 555 7423 3107 -1013
431 4311 1579 -279 556 7446 3120 -1020
432 4338 1591 -284 557 7469 3133 -1027
433 4366 1603 -288 558 7492 3146 -1035
434 4393 1614 -292 559 7515 3159 -1042
435 4421 1626 -297 560 7538 3171 -1050
436 4448 1638 -301 561 7561 3184 -1058
437 4475 1650 -306 562 7584 3197 -1065
438 4503 1662 -310 563 7607 3210 -1073
439 4530 1674 -315 564 7629 3223 -1080
440 4557 1686 -319 565 7652 3235 -1088
441 4584 1698 -324 566 7675 3248 -1096
442 4611 1710 -328 567 7697 3261 -1103
443 4638 1722 -333 568 7720 3274 -1111
444 4665 1734 -338 569 7743 3287 -1119
445 4692 1746 -342 570 7765 3300 -1126
131
446 4719 1758 -347 571 7788 3313 -1134
447 4746 1770 -352 572 7811 3326 -1142
448 4773 1782 -356 573 7833 3338 -1150
449 4800 1794 -361 574 7856 3351 -1158
450 4826 1806 -366 575 7878 3364 -1166
451 4853 1818 -371 576 7901 3377 -1173
452 4880 1830 -376 577 7923 3390 -1181
453 4906 1842 -381 578 7945 3403 -1189
454 4933 1854 -386 579 7968 3416 -1197
455 4959 1866 -391 580 7990 3429 -1205
456 4986 1878 -396 581 8012 3442 -1213
457 5012 1890 -401 582 8035 3455 -1221
458 5039 1902 -406 583 8057 3468 -1229
459 5065 1914 -411 584 8079 3481 -1237
460 5091 1926 -416 585 8101 3494 -1245
461 5118 1938 -421 586 8124 3507 -1254
462 5144 1951 -426 587 8146 3520 -1262
463 5170 1963 -431 588 8168 3533 -1270
464 5196 1975 -436 589 8190 3546 -1278
465 5222 1987 -441 590 8212 3559 -1286
466 5248 1999 -447 591 8234 3572 -1294
467 5274 2011 -452 592 8256 3585 -1303
468 5300 2023 -457 593 8278 3598 -1311
469 5326 2035 -463 594 8300 3611 -1319
470 5352 2048 -468 595 8322 3624 -1328
471 5378 2060 -473 596 8344 3637 -1336
472 5404 2072 -479 597 8366 3650 -1344
473 5430 2084 -484 598 8388 3663 -1353
474 5455 2096 -490 599 8410 3676 -1361
475 5481 2108 -495 600 8432 3690 -1369
476 5507 2121 -500 601 8454 3703 -1378
477 5532 2133 -506 602 8475 3716 -1386
478 5558 2145 -512 603 8497 3729 -1395
479 5583 2157 -517 604 8519 3742 -1403
480 5609 2170 -523 605 8541 3755 -1412
481 5634 2182 -528 606 8562 3768 -1420
482 5660 2194 -534 607 8584 3781 -1429
483 5685 2206 -540 608 8606 3795 -1438
484 5710 2219 -545 609 8627 3808 -1446
485 5736 2231 -551 610 8649 3821 -1455
132
486 5761 2243 -557 611 8670 3834 -1464
487 5786 2255 -563 612 8692 3847 -1472
488 5812 2268 -568 613 8713 3860 -1481
489 5837 2280 -574 614 8735 3874 -1490
490 5862 2292 -580 615 8756 3887 -1498
491 5887 2305 -586 616 8778 3900 -1507
492 5912 2317 -592 617 8799 3913 -1516
493 5937 2329 -598 618 8821 3926 -1525
494 5962 2342 -604 619 8842 3940 -1534
495 5987 2354 -610 620 8864 3953 -1542
496 6012 2366 -616 621 8885 3966 -1551
497 6037 2379 -622 622 8906 3979 -1560
498 6062 2391 -628 623 8928 3993 -1569
499 6086 2403 -634 62315 8931 3995 -1570
133
Appendix G
Table G1 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid I state (29815-33715K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 319 578 162 -004
299 024 000 000 320 606 170 -005
300 052 000 000 321 633 179 -005
301 080 007 000 322 660 188 -006
302 108 016 000 323 688 197 -007
303 136 024 000 324 715 205 -007
304 164 032 000 325 742 214 -008
305 192 041 000 326 769 223 -009
306 219 049 000 327 796 232 -009
307 247 058 000 328 823 241 -010
308 275 067 -001 329 851 250 -011
309 303 075 -001 330 878 259 -011
310 330 084 -001 331 905 268 -012
311 358 092 -001 332 932 277 -013
312 386 101 -002 333 959 285 -014
313 413 109 -002 334 985 294 -015
314 441 118 -002 335 1012 303 -016
315 468 127 -003 336 1039 312 -017
316 496 135 -003 337 1066 321 -018
317 523 144 -003 33715 1070 331 -019
318 551 153 -004
Table G2 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
solid II state (36115-36415K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36115 2433 825 -054
134
362 2454 832 -056
363 2478 841 -059
364 2503 850 -061
36415 2506 851 -062
Table G3 Thermodynamic properties of LiNO3-KNO3-NaNO2-Mg(NO3)2 compound in
liquid state (41115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
41115 3833 1366 -210 518 6604 2649 -772
412 3857 1376 -213 519 6628 2661 -778
413 3885 1387 -217 520 6652 2674 -785
414 3913 1399 -221 521 6675 2686 -792
415 3941 1411 -225 522 6699 2699 -798
416 3969 1422 -229 523 6723 2711 -805
417 3997 1434 -233 524 6747 2723 -812
418 4025 1446 -237 525 6770 2736 -819
419 4053 1457 -241 526 6794 2748 -825
420 4081 1469 -245 527 6818 2761 -832
421 4109 1481 -249 528 6841 2773 -839
422 4137 1493 -253 529 6865 2786 -846
423 4165 1504 -257 530 6888 2798 -853
424 4192 1516 -262 531 6912 2810 -860
425 4220 1528 -266 532 6935 2823 -867
426 4248 1539 -270 533 6959 2835 -873
427 4275 1551 -274 534 6982 2848 -880
428 4303 1563 -279 535 7005 2860 -887
429 4330 1575 -283 536 7029 2873 -894
430 4358 1587 -287 537 7052 2885 -902
431 4385 1598 -292 538 7075 2898 -909
432 4412 1610 -296 539 7098 2910 -916
433 4439 1622 -300 540 7122 2923 -923
434 4467 1634 -305 541 7145 2935 -930
135
435 4494 1646 -309 542 7168 2948 -937
436 4521 1657 -314 543 7191 2960 -944
437 4548 1669 -318 544 7214 2973 -951
438 4575 1681 -323 545 7237 2986 -959
439 4602 1693 -328 546 7260 2998 -966
440 4629 1705 -332 547 7283 3011 -973
441 4656 1716 -337 548 7306 3023 -980
442 4683 1728 -341 549 7329 3036 -988
443 4710 1740 -346 550 7352 3048 -995
444 4736 1752 -351 551 7375 3061 -1003
445 4763 1764 -356 552 7398 3074 -1010
446 4790 1776 -360 553 7420 3086 -1017
447 4816 1788 -365 554 7443 3099 -1025
448 4843 1800 -370 555 7466 3111 -1032
449 4869 1812 -375 556 7489 3124 -1040
450 4896 1823 -380 557 7511 3137 -1047
451 4922 1835 -385 558 7534 3149 -1055
452 4949 1847 -390 559 7557 3162 -1062
453 4975 1859 -395 560 7579 3175 -1070
454 5002 1871 -400 561 7602 3187 -1077
455 5028 1883 -405 562 7625 3200 -1085
456 5054 1895 -410 563 7647 3213 -1093
457 5080 1907 -415 564 7670 3225 -1100
458 5106 1919 -420 565 7692 3238 -1108
459 5132 1931 -425 566 7714 3251 -1116
460 5159 1943 -430 567 7737 3263 -1123
461 5185 1955 -435 568 7759 3276 -1131
462 5211 1967 -440 569 7782 3289 -1139
463 5236 1979 -446 570 7804 3302 -1147
464 5262 1991 -451 571 7826 3314 -1155
465 5288 2003 -456 572 7849 3327 -1162
466 5314 2015 -461 573 7871 3340 -1170
467 5340 2027 -467 574 7893 3352 -1178
468 5366 2039 -472 575 7915 3365 -1186
469 5391 2051 -478 576 7937 3378 -1194
470 5417 2063 -483 577 7960 3391 -1202
471 5442 2075 -488 578 7982 3404 -1210
472 5468 2087 -494 579 8004 3416 -1218
473 5494 2099 -499 580 8026 3429 -1226
474 5519 2111 -505 581 8048 3442 -1234
136
475 5545 2123 -510 582 8070 3455 -1242
476 5570 2135 -516 583 8092 3468 -1250
477 5595 2147 -521 584 8114 3480 -1258
478 5621 2160 -527 585 8136 3493 -1266
479 5646 2172 -533 586 8158 3506 -1274
480 5671 2184 -538 587 8180 3519 -1283
481 5696 2196 -544 588 8201 3532 -1291
482 5722 2208 -550 589 8223 3545 -1299
483 5747 2220 -555 590 8245 3557 -1307
484 5772 2232 -561 591 8267 3570 -1315
485 5797 2244 -567 592 8289 3583 -1324
486 5822 2257 -573 593 8310 3596 -1332
487 5847 2269 -579 594 8332 3609 -1340
488 5872 2281 -585 595 8354 3622 -1349
489 5897 2293 -590 596 8375 3635 -1357
490 5922 2305 -596 597 8397 3648 -1365
491 5947 2317 -602 598 8419 3660 -1374
492 5971 2330 -608 599 8440 3673 -1382
493 5996 2342 -614 600 8462 3686 -1391
494 6021 2354 -620 601 8483 3699 -1399
495 6046 2366 -626 602 8505 3712 -1408
496 6070 2379 -632 603 8526 3725 -1416
497 6095 2391 -638 604 8548 3738 -1425
498 6119 2403 -645 605 8569 3751 -1433
499 6144 2415 -651 606 8591 3764 -1442
500 6169 2427 -657 607 8612 3777 -1451
501 6193 2440 -663 608 8633 3790 -1459
502 6217 2452 -669 609 8655 3803 -1468
503 6242 2464 -675 610 8676 3816 -1476
504 6266 2477 -682 611 8697 3829 -1485
505 6291 2489 -688 612 8719 3842 -1494
506 6315 2501 -694 613 8740 3855 -1503
507 6339 2513 -701 614 8761 3868 -1511
508 6363 2526 -707 615 8782 3881 -1520
509 6388 2538 -713 616 8803 3894 -1529
510 6412 2550 -720 617 8825 3907 -1538
511 6436 2563 -726 618 8846 3920 -1547
512 6460 2575 -733 619 8867 3933 -1555
513 6484 2587 -739 620 8888 3946 -1564
514 6508 2600 -746 621 8909 3959 -1573
137
515 6532 2612 -752 622 8930 3972 -1582
516 6556 2624 -759 623 8951 3985 -1591
517 6580 2637 -765 62315 8954 3987 -1592
138
Appendix H
Table H1 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid I
state (29815-35415K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 768 241 -011
299 023 007 000 328 794 249 -011
300 050 015 000 329 820 258 -012
301 077 023 000 330 846 266 -013
302 104 031 000 331 872 275 -014
303 131 039 000 332 898 284 -015
304 158 048 000 333 924 292 -016
305 185 056 -001 334 950 301 -016
306 212 064 -001 335 976 310 -017
307 239 072 -001 336 1002 318 -018
308 265 081 -001 337 1028 327 -019
309 292 089 -001 338 1053 336 -020
310 319 097 -002 339 1079 344 -021
311 345 105 -002 340 1105 353 -022
312 372 114 -002 341 1130 362 -024
313 399 122 -003 342 1156 371 -025
314 425 130 -003 343 1182 379 -026
315 452 139 -004 344 1207 388 -027
316 478 147 -004 345 1233 397 -028
317 505 156 -004 346 1258 406 -029
318 531 164 -005 347 1284 415 -031
319 558 172 -005 348 1309 424 -032
320 584 181 -006 349 1335 433 -033
321 611 189 -007 350 1360 441 -035
322 637 198 -007 351 1385 450 -036
323 663 206 -008 352 1411 459 -037
324 689 215 -008 353 1436 468 -039
325 716 223 -009 354 1461 477 -040
326 742 232 -010 35415 1465 478 -040
139
Table H2 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in solid 2
state (36215-37315K)
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol)
36215 2387 777 -046
363 2408 809 -055
364 2432 817 -057
365 2457 826 -060
366 2481 835 -062
367 2506 843 -065
368 2530 852 -067
369 2555 861 -070
370 2579 870 -072
371 2604 879 -075
372 2628 888 -077
373 2653 898 -080
37315 2657 907 -083
Table H3 Thermodynamic properties of LiNO3-KNO3-NaNO2-KNO2 compound in liquid
state (37915-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
37915 2966 1025 -100 502 6174 2432 -667
380 2991 1034 -102 503 6198 2444 -674
381 3020 1045 -105 504 6222 2456 -680
382 3048 1056 -108 505 6246 2468 -686
383 3077 1067 -112 506 6270 2480 -692
384 3105 1078 -115 507 6294 2492 -699
385 3134 1089 -118 508 6317 2504 -705
386 3162 1100 -121 509 6341 2516 -711
387 3191 1111 -124 510 6365 2528 -718
140
388 3219 1122 -127 511 6388 2541 -724
389 3247 1133 -130 512 6412 2553 -730
390 3275 1144 -134 513 6436 2565 -737
391 3304 1155 -137 514 6459 2577 -743
392 3332 1166 -140 515 6483 2589 -750
393 3360 1177 -144 516 6506 2601 -756
394 3388 1188 -147 517 6530 2613 -763
395 3416 1199 -150 518 6553 2625 -769
396 3444 1210 -154 519 6577 2638 -776
397 3472 1221 -157 520 6600 2650 -782
398 3500 1232 -161 521 6624 2662 -789
399 3527 1243 -164 522 6647 2674 -796
400 3555 1254 -168 523 6670 2686 -802
401 3583 1265 -171 524 6694 2698 -809
402 3611 1276 -175 525 6717 2711 -816
403 3638 1287 -179 526 6740 2723 -822
404 3666 1299 -182 527 6763 2735 -829
405 3693 1310 -186 528 6786 2747 -836
406 3721 1321 -190 529 6810 2760 -843
407 3748 1332 -193 530 6833 2772 -850
408 3776 1343 -197 531 6856 2784 -856
409 3803 1354 -201 532 6879 2796 -863
410 3830 1366 -205 533 6902 2809 -870
411 3857 1377 -209 534 6925 2821 -877
412 3885 1388 -213 535 6948 2833 -884
413 3912 1399 -216 536 6971 2845 -891
414 3939 1410 -220 537 6994 2858 -898
415 3966 1422 -224 538 7017 2870 -905
416 3993 1433 -228 539 7040 2882 -912
417 4020 1444 -232 540 7063 2895 -919
418 4047 1455 -236 541 7086 2907 -926
419 4074 1467 -240 542 7108 2919 -933
420 4101 1478 -245 543 7131 2932 -940
421 4128 1489 -249 544 7154 2944 -947
422 4154 1500 -253 545 7177 2957 -955
423 4181 1512 -257 546 7199 2969 -962
424 4208 1523 -261 547 7222 2981 -969
425 4234 1534 -265 548 7245 2994 -976
426 4261 1546 -270 549 7267 3006 -984
427 4288 1557 -274 550 7290 3019 -991
141
428 4314 1568 -278 551 7313 3031 -998
429 4341 1580 -282 552 7335 3044 -1005
430 4367 1591 -287 553 7358 3056 -1013
431 4393 1602 -291 554 7380 3068 -1020
432 4420 1614 -296 555 7403 3081 -1028
433 4446 1625 -300 556 7425 3093 -1035
434 4472 1636 -305 557 7448 3106 -1042
435 4499 1648 -309 558 7470 3118 -1050
436 4525 1659 -314 559 7492 3131 -1057
437 4551 1671 -318 560 7515 3143 -1065
438 4577 1682 -323 561 7537 3156 -1072
439 4603 1694 -327 562 7560 3169 -1080
440 4629 1705 -332 563 7582 3181 -1087
441 4655 1716 -336 564 7604 3194 -1095
442 4681 1728 -341 565 7626 3206 -1103
443 4707 1739 -346 566 7649 3219 -1110
444 4733 1751 -351 567 7671 3231 -1118
445 4759 1762 -355 568 7693 3244 -1126
446 4785 1774 -360 569 7715 3257 -1133
447 4810 1785 -365 570 7737 3269 -1141
448 4836 1797 -370 571 7759 3282 -1149
449 4862 1808 -375 572 7782 3294 -1157
450 4888 1820 -379 573 7804 3307 -1164
451 4913 1832 -384 574 7826 3320 -1172
452 4939 1843 -389 575 7848 3332 -1180
453 4964 1855 -394 576 7870 3345 -1188
454 4990 1866 -399 577 7892 3358 -1196
455 5015 1878 -404 578 7914 3370 -1204
456 5041 1889 -409 579 7936 3383 -1212
457 5066 1901 -414 580 7957 3396 -1220
458 5092 1913 -419 581 7979 3408 -1228
459 5117 1924 -424 582 8001 3421 -1236
460 5142 1936 -430 583 8023 3434 -1244
461 5167 1947 -435 584 8045 3447 -1252
462 5193 1959 -440 585 8067 3459 -1260
463 5218 1971 -445 586 8088 3472 -1268
464 5243 1982 -450 587 8110 3485 -1276
465 5268 1994 -456 588 8132 3498 -1284
466 5293 2006 -461 589 8154 3510 -1292
467 5318 2017 -466 590 8175 3523 -1300
142
468 5343 2029 -472 591 8197 3536 -1308
469 5368 2041 -477 592 8219 3549 -1317
470 5393 2053 -482 593 8240 3562 -1325
471 5418 2064 -488 594 8262 3574 -1333
472 5443 2076 -493 595 8283 3587 -1341
473 5468 2088 -499 596 8305 3600 -1350
474 5493 2100 -504 597 8327 3613 -1358
475 5517 2111 -510 598 8348 3626 -1366
476 5542 2123 -515 599 8370 3639 -1375
477 5567 2135 -521 600 8391 3652 -1383
478 5592 2147 -526 601 8413 3664 -1391
479 5616 2158 -532 602 8434 3677 -1400
480 5641 2170 -537 603 8455 3690 -1408
481 5665 2182 -543 604 8477 3703 -1417
482 5690 2194 -549 605 8498 3716 -1425
483 5715 2206 -554 606 8520 3729 -1434
484 5739 2218 -560 607 8541 3742 -1442
485 5763 2229 -566 608 8562 3755 -1451
486 5788 2241 -572 609 8583 3768 -1459
487 5812 2253 -578 610 8605 3781 -1468
488 5837 2265 -583 611 8626 3794 -1477
489 5861 2277 -589 612 8647 3807 -1485
490 5885 2289 -595 613 8668 3820 -1494
491 5910 2301 -601 614 8690 3833 -1503
492 5934 2313 -607 615 8711 3846 -1511
493 5958 2324 -613 616 8732 3859 -1520
494 5982 2336 -619 617 8753 3872 -1529
495 6006 2348 -625 618 8774 3885 -1538
496 6030 2360 -631 619 8795 3898 -1546
497 6055 2372 -637 620 8816 3911 -1555
498 6079 2384 -643 621 8837 3924 -1564
499 6103 2396 -649 622 8858 3937 -1573
500 6127 2408 -655 623 8879 3950 -1582
501 6151 2420 -661 62315 8883 3952 -1583
143
Appendix I
Table I1 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in solid state (29815-35315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
29815 000 000 000 327 1171 366 -017
299 035 010 000 328 1211 379 -018
300 076 023 000 329 1250 392 -019
301 117 035 000 330 1290 405 -021
302 158 048 000 331 1330 418 -022
303 199 060 000 332 1369 431 -023
304 240 072 -001 333 1409 444 -025
305 281 085 -001 334 1448 458 -026
306 322 097 -001 335 1488 471 -028
307 363 110 -002 336 1527 484 -029
308 404 122 -002 337 1566 497 -031
309 445 135 -002 338 1605 510 -032
310 486 148 -003 339 1644 524 -034
311 526 160 -003 340 1683 537 -036
312 567 173 -004 341 1722 550 -037
313 608 186 -005 342 1761 563 -039
314 648 198 -005 343 1800 577 -041
315 689 211 -006 344 1839 590 -043
316 729 224 -007 345 1877 603 -044
317 770 237 -007 346 1916 617 -046
318 810 250 -008 347 1955 630 -048
319 850 262 -009 348 1993 643 -050
320 891 275 -010 349 2031 657 -052
321 931 288 -011 350 2070 670 -054
322 971 301 -012 351 2108 683 -056
323 1011 314 -013 352 2146 697 -059
324 1051 327 -014 353 2184 710 -061
325 1091 340 -015 35315 2190 712 -061
326 1131 353 -016
144
Table I2 Thermodynamic properties of LiNO3-NaNO3 -KNO3-Mg(NO3)2-MgK compound
in liquid state (39115-62315K)
T(K) ΔS ΔH ΔG
T(K) ΔS ΔH ΔG
(JmolK) (kJmol) (kJmol) (JmolK) (kJmol) (kJmol)
39115 4413 1056 -191 508 8890 3521 -978
392 4450 1535 -195 509 8924 3538 -986
393 4492 1549 -200 510 8959 3556 -995
394 4535 1566 -204 511 8993 3574 -1004
395 4577 1583 -209 512 9027 3591 -1013
396 4620 1599 -213 513 9062 3609 -1022
397 4662 1616 -218 514 9096 3626 -1031
398 4704 1633 -223 515 9130 3644 -1041
399 4746 1650 -227 516 9164 3661 -1050
400 4789 1666 -232 517 9198 3679 -1059
401 4831 1683 -237 518 9232 3697 -1068
402 4872 1700 -242 519 9266 3714 -1077
403 4914 1717 -247 520 9300 3732 -1087
404 4956 1734 -252 521 9334 3750 -1096
405 4997 1751 -257 522 9368 3767 -1105
406 5039 1767 -262 523 9402 3785 -1115
407 5080 1784 -267 524 9435 3802 -1124
408 5122 1801 -272 525 9469 3820 -1134
409 5163 1818 -277 526 9503 3838 -1143
410 5204 1835 -282 527 9536 3855 -1152
411 5245 1852 -287 528 9570 3873 -1162
412 5286 1869 -293 529 9603 3891 -1172
413 5327 1885 -298 530 9637 3908 -1181
414 5368 1902 -303 531 9670 3926 -1191
415 5409 1919 -309 532 9703 3944 -1201
416 5450 1936 -314 533 9737 3962 -1210
417 5490 1953 -320 534 9770 3979 -1220
418 5531 1970 -325 535 9803 3997 -1230
419 5571 1987 -331 536 9836 4015 -1240
420 5612 2004 -336 537 9869 4032 -1249
421 5652 2021 -342 538 9902 4050 -1259
145
422 5692 2038 -347 539 9935 4068 -1269
423 5732 2055 -353 540 9968 4086 -1279
424 5772 2072 -359 541 10001 4104 -1289
425 5812 2089 -365 542 10034 4121 -1299
426 5852 2106 -371 543 10066 4139 -1309
427 5892 2123 -376 544 10099 4157 -1319
428 5932 2140 -382 545 10132 4175 -1329
429 5971 2157 -388 546 10165 4192 -1340
430 6011 2174 -394 547 10197 4210 -1350
431 6051 2191 -400 548 10230 4228 -1360
432 6090 2208 -406 549 10262 4246 -1370
433 6129 2225 -412 550 10295 4264 -1380
434 6169 2242 -419 551 10327 4282 -1391
435 6208 2259 -425 552 10359 4299 -1401
436 6247 2276 -431 553 10392 4317 -1411
437 6286 2293 -437 554 10424 4335 -1422
438 6325 2310 -444 555 10456 4353 -1432
439 6364 2327 -450 556 10488 4371 -1443
440 6403 2344 -456 557 10520 4389 -1453
441 6442 2361 -463 558 10553 4407 -1464
442 6480 2378 -469 559 10585 4424 -1474
443 6519 2395 -476 560 10617 4442 -1485
444 6557 2412 -482 561 10648 4460 -1496
445 6596 2429 -489 562 10680 4478 -1506
446 6634 2446 -495 563 10712 4496 -1517
447 6673 2464 -502 564 10744 4514 -1528
448 6711 2481 -509 565 10776 4532 -1538
449 6749 2498 -515 566 10808 4550 -1549
450 6787 2515 -522 567 10839 4568 -1560
451 6825 2532 -529 568 10871 4586 -1571
452 6863 2549 -536 569 10902 4604 -1582
453 6901 2566 -543 570 10934 4622 -1593
454 6939 2584 -550 571 10965 4640 -1604
455 6977 2601 -557 572 10997 4658 -1615
456 7015 2618 -564 573 11028 4676 -1626
457 7052 2635 -571 574 11060 4694 -1637
458 7090 2652 -578 575 11091 4712 -1648
459 7128 2670 -585 576 11122 4730 -1659
460 7165 2687 -592 577 11154 4748 -1670
461 7202 2704 -599 578 11185 4766 -1681
146
462 7240 2721 -606 579 11216 4784 -1692
463 7277 2738 -614 580 11247 4802 -1704
464 7314 2756 -621 581 11278 4820 -1715
465 7351 2773 -628 582 11309 4838 -1726
466 7388 2790 -636 583 11340 4856 -1737
467 7425 2807 -643 584 11371 4874 -1749
468 7462 2825 -650 585 11402 4892 -1760
469 7499 2842 -658 586 11433 4910 -1772
470 7536 2859 -665 587 11464 4928 -1783
471 7573 2877 -673 588 11495 4946 -1794
472 7609 2894 -680 589 11525 4964 -1806
473 7646 2911 -688 590 11556 4982 -1817
474 7682 2928 -696 591 11587 5001 -1829
475 7719 2946 -703 592 11617 5019 -1841
476 7755 2963 -711 593 11648 5037 -1852
477 7792 2980 -719 594 11678 5055 -1864
478 7828 2998 -727 595 11709 5073 -1876
479 7864 3015 -735 596 11739 5091 -1887
480 7900 3032 -742 597 11770 5109 -1899
481 7937 3050 -750 598 11800 5128 -1911
482 7973 3067 -758 599 11831 5146 -1923
483 8009 3084 -766 600 11861 5164 -1935
484 8045 3102 -774 601 11891 5182 -1946
485 8080 3119 -782 602 11921 5200 -1958
486 8116 3137 -791 603 11952 5218 -1970
487 8152 3154 -799 604 11982 5237 -1982
488 8188 3171 -807 605 12012 5255 -1994
489 8223 3189 -815 606 12042 5273 -2006
490 8259 3206 -823 607 12072 5291 -2018
491 8294 3224 -832 608 12102 5309 -2030
492 8330 3241 -840 609 12132 5328 -2042
493 8365 3259 -848 610 12162 5346 -2055
494 8401 3276 -857 611 12192 5364 -2067
495 8436 3293 -865 612 12222 5382 -2079
496 8471 3311 -873 613 12252 5401 -2091
497 8506 3328 -882 614 12281 5419 -2103
498 8542 3346 -890 615 12311 5437 -2116
499 8577 3363 -899 616 12341 5456 -2128
500 8612 3381 -908 617 12370 5474 -2140
501 8647 3398 -916 618 12400 5492 -2153
147
502 8681 3416 -925 619 12430 5510 -2165
503 8716 3433 -934 620 12459 5529 -2178
504 8751 3451 -942 621 12489 5547 -2190
505 8786 3468 -951 622 12518 5565 -2203
506 8820 3486 -960 623 12548 5584 -2215
507 8855 3503 -969 62315 12552 5602 -2217