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Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
REDUCING THE ENERGY CONSUMPTION IN BUILDINGS BY INCORPORATING MICROENCAPSULATED PCMS
IN RIGID POLYURETHANE FOAMS
Manuel Salvador Carmona Franco
Ana María Borreguero Simón
Beatriz Talavera Almena
Ángel Serrano Casero
Ignacio Garrido Sáenz
Juan Francisco Rodríguez Romero
Institute of Chemical and Environmental Technology
Chemical Engineering Department
University of Castilla La Mancha
Ciudad Real, Spain
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
INTRODUCTION. THERMAL ENERGY STORAGE MATERIALS
A PCM is a substance with a high heat of fusion which, melting and solidifying, is able to absorb and store or release large amounts of energy.
ABSORB
STORE
RELEASE
Wide variety of PCMs can be used: Inorganics ( hydrated salts) Organics (alkanes, paraffin, waxes)
Development of new systems
for saving energy
Use of new renewable
energy sources
SOLAR ENERGY
IT NEEDS TO BE STORED!
Petroleum 50 years
Carbon 330 years
Uranium reactors 1000 years
Nuclear Fission 1 Million of years
Solar Energy 5000 millions of years
Energy sources
CLEAN UNIVERSAL RENEWABLE
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
INTRODUCTION. HOW DO PCMS WORK?
HOT OUTSIDE
BUILDING INSIDE
Heat Released
COLD
OUTSIDE
Heat Required
BUILDING INSIDE
External T > Melting T PCM becomes liquid
(Heat required)
External T < Freezing T PCM solidifies (Heat released)
Properties of PCMs for applications in buildings: • Melting temperature about 25ºC • High latent heat • Low cost • Good availability. • Non-toxic • Non-corrosive
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
INTRODUCTION. PCMs INCORPORATION IN BUILDINGS
• Building systems for PCMs incorporation
• Wallboards, ceilings and floors
• Shutter of windows
• Cooling and heating systems
• Ways of PCMs incorporation
• Direct incorporation
• PCMs microencapsulation
SHELL
CORE
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
Avoid loosing the PCM.
Avoid interactions between PCMs and the rest of building
materials.
Safe handling of PCMs.
Handling liquids as solid.
Increase the area of heat transfer.
INTRODUCTION. PCMs INCORPORATION IN BUILDINGS
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
INTRODUCTION. MICROENCAPSULATION OF PCMs
Spray drying technique
Suspension polymerization
Gas for solvent evaporation
Feed
Gas + solvent Product
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
INTRODUCTION. MICROENCAPSULATED PCMs PROPERTIES
Low Angle Laser Light Scattering (LALLS)
Scanning Electron Microscopy (SEM)
Differential
Scanning
Calorimetry
(DSC)
mSD-(LDPE-EVA-RT27)
-10 0 10 20 30 40-3
-2
-1
0
Hf=96,2 J/g
Hf=96,7 J/g
Inte
nsi
dad (
u.a
.)
Temperature (ºC)
Material
Original
After thermal treatment
Hf=85,81J/g
Hf=85,6J/g
-10 0 10 20 30 40-4
-3
-2
-1
0
HfJ/g
HfJ/g
Inte
nsi
ty (
u.a
.)
Temperatura (ºC)
Microcapsule
Pure paraffin
Hf=85,81J/
g Hf=200.2J/g
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
OBJETIVE. WHY USE PCMs IN BULDINGS?
EU directive 2010/31/UE: Directive on Energy Performance of Buildings
- Buildings are responsible for 40% of energy consumption and 36% of CO2 emissions in the
Europe Community.
- Energy performance of buildings is key to achieve the EU Climate and Energy objectives.
Money spent in energy
Reduction of
Environmental pollution
Energy consumption in heaters and air
conditioners
Development of buildings with a more efficient use of energy
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
EXTERNAL
SHEET
RESIN
CORE
(POLYURETHANE FOAM)
SANDWICH PANELS
EPOXI RESINS POLYURETHANE FOAMS
OBJETIVE. INCORPORATION OF PCMs IN BUILDINGS MATERIALS
The aim of this work is to develop sandwich panels exhibiting
high TES capacity
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
EXPERIMENTAL PROCEDURE. FOAM SYNTHESIS
n O=C=N-R–N=C=O + n HO-R’-OH
Polyisocyanate Polyol Polyurethane
[-CO-NH-R–NH-CO-O-R’-O-] n
Polyol
Additives (blowing agent,
surfactant and catalyst)
PCMs
Mix
Polyisocyanate
Different
microencapsulated
PCMs contents
• Microcapsules distribution
• Latent Heat
• Foam structure and cell size
• Density
• Mechanical resistance
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
1. Rotameter
2. Signal Transmitter
3. Computer for data recording
4. Peristaltic Pump
5. Thermostatic Bath
6. Termocouples
7. Isothermal Chamber
8. Insulating Structure
Experimental set up for thermal characterization
EXPERIMENTAL PROCEDURE. THERMAL ANALYSIS
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
Upper Tª
Middle Tª
Plate Tª
Upper Tª
Middle Tª
Plate Tª
Flow
Direction
Sensor Q out
Sensor Q in
Sensor
Q side
Sensor
Q side
Flow
Direction
EXPERIMENTAL PROCEDURE. THERMAL ANALYSIS
THERMOCOUPLES DISTRIBUTION
HEAT FLUX SENSORS DISTRIBUTION
10 cm
3 c
m
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
EXPERIMENTAL PROCEDURE. THERMAL ANALYSIS
Modulated Differential Scanning Calorimetry (MDSC)
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
EXPERIMENTAL PROCEDURE. MECHANICAL RESISTANCE
Mechanical characterization
Compression Experimental Set up
Uniaxial compression tests were performed according to ASTM D1621
(Standard Test Method for Compressive Properties of Rigid Cellular Plastics)
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
RESULTS AND DISCUSSION. SYNTHESIZED PU FOAMS
Microcapsules Content (%wt)
Foam system
viscosity
Rising
Rate
Final Foam
Height
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
RESULTS AND DISCUSSION. DENSITY
Density > 30kg/m3
(UNE 92120)
(prEN 14318-2)
Microcapsules Content (%wt)
Density
0% 10%
40% 50% 30%
15% 20%
0
50
100
150
200
250
300
350
0 10 20 30 40 50
De
nsi
ty (
kg/m
3 )
% PCM
Zone 1 Zone 2
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
RESULTS AND DISCUSSION. DSC ANALYSIS
-0,45
-0,4
-0,35
-0,3
-0,25
-0,2
-0,15
-0,1
-0,05
0
-10 0 10 20 30 40 50 60 70
Inte
nsi
ty (
u.a
)
Temperature (ºC)
0% Middle
10% Middle
20% Middle
30% Middle
40% Middle
50% Middle
% PCM QDOWN
(J/g)
QMIDDLE
(J/g)
QUP
(J/g)
QEXP
(J/g)
QTH
(J/g)
0 0 0 0 0 0
10 7,46 7,014 7,77 7,41 8,58
20 16,57 15,82 16,71 16,37 17,16
30 26,49 25,44 24,57 25,50 25,74
40 36,52 33,82 32,9 34,41 34,32
50 39,21 40,57 37,31 39,03 42,91
3
1
3
1exp
··
i
ii
ii
i
i
erimental
V
VQ
Q
Microcapsules were homogeneously
distributed into the whole foam
Microcapsules
Content (%wt)
Latent
Heat
)(gWeightFoam
(g)masslesmicrocapsu(J/g)Q(J/g)Q
lesmicrocápsu
ltheoretica
Hf=40.57 J/g
T=23.5ºC
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
RESULTS AND DISCUSSION. CELL STRUCTURE AND SIZE
SEM photographs of PU foams with different microcapsules content
RPU are formed with microcapsules into the strut and also the cell wall
0% 10% 20%
30% 40% 50%
0%
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
RESULTS AND DISCUSSION. COMPRESSION TESTS
S=0.2-8 MPa/g/cm3 y E=2-200MPa/g/cm3
No significant difference between the values of foams containing 0 to 20wt%
Sharp decrease in the mechanical resistance for contents higher than 20wt%
0
1
2
3
4
5
6
0 10 20 30 40 50
Spe
cifi
c C
om
pre
ssiv
e S
tre
ngt
h S
(M
pa/
(g/c
m3
))
% PCM
0
10
20
30
40
50
60
70
80
0 10 20 30 40 50
Spe
cifi
c C
om
pre
ssiv
e M
od
ulu
s E
(Mp
a/(g
/cm
3))
% PCM
Uniaxial compression tests were performed according to ASTM D1621
Specific compression strength and modulus for excluding the density effect
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
3. PROCEDI-
MIENTO
EXPERIMENTAL
1. INTRO-
DUCCIÓN
2. OBJETIVOS
4. RESULTADOS
5. CONCLU-
SIONES
RESULTS AND DISCUSSION. THERMAL ANALYSIS
Experimental variation of temperatures at different points in a RPU foam without PCM
Influence of Temperature
15
20
25
30
35
40
0 2000 4000 6000 8000 10000 12000 14000
Tem
pe
ratu
re (
ºC)
t (s)
Tdown2
Tup2
Tbath
Tup1
Tenvironment
Tmiddle2
Tdown1
Tmiddle1
Tinsulation
Tbath change in step 18 to 40ºC
Tup1 =Tup2
Tmiddle1 =Tmiddle2
Tdown1 =Tdown2
One dimensional flow Termocouples opposite to the flow
with the same temperature profile
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
RESULTS AND DISCUSSION. THERMAL ANALYSIS
15
20
25
30
35
40
0 5000 10000 15000 20000
Tem
pe
ratu
re (
ºC)
t (s)
Tdown average 0%
Tdown average 10%
Tdown average 20%
Tdown average 40%
Tdown average 50%
Tbath
0
20
40
60
80
100
120
140
0 5000 10000 15000 20000
Q (
W/m
2 )
t (s)
q in 0% (W/m2)
q in 10% (W/m2)
q in 20% (W/m2)
q in 30% (W/m2)
q in 40% (W/m2)
q in 50% (W/m2)
This behavior is more clear
with percentages higher than
20%
Hot Plate Temperature
Input Heat Flux
Down Temperature
Microcapsules Content (%wt)
Thermal
Damping
Slope of
the curves
Microcapsules Content (%wt)
Input
heat Flux
Maximum energy absorb
or lower insulating effect
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
RESULTS AND DISCUSSION. THERMAL ANALYSIS
-12
-10
-8
-6
-4
-2
0
0 5000 10000 15000 20000
Q (
W/m
2 )
t (s)
q out 0% (W/m2)
q out 10% (W/m2)
q out 20% (W/m2)
q out 30% (W/m2)
q out 40% (W/m2)
q out 50% (W/m2)
Similar temperatures at stationary condition, but
big difference in the transition step
15
20
25
30
35
40
0 5000 10000 15000 20000
Tem
pe
ratu
re (
ºC)
t (s)
Tup average 0%
Tup average 10%
Tup average 20%
Tup average 30%
Tup average 40%
Tup average 50%
Tbath
Hot Plate Temperature
3 cm in thickness
External Temperature
Output Heat Flux
Melting of PCM by energy
absorption
Microcapsules Content (%wt)
Output
heat Flux
Ability to
store energy
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
Influence of Heat Flows
RESULTS AND DISCUSSION. THERMAL ANALYSIS
Accumulation curves as a function of time and the percentage content of PCMs
THERMAL ENERGY STORAGE (TES)
-0,1
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
0 5000 10000 15000 20000
Q (
W)
t (s)
Accumulated (W) 0%
Accumulated (W) 10%
Accumulated (W) 20%
Accumulated (W) 30%
Accumulated (W) 40%
Accumulated (W) 50%
Microcapsules
Content (%wt)
Total energy absorbed during one
step temperature change 18ªC-40ªC
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
𝑐𝑝 =𝑞𝑎𝑐
𝑚𝑝𝑟𝑜𝑏𝑒𝑡𝑎 · 𝑇𝑓 − 𝑇𝑖
𝜅 =𝑄𝑖𝑛𝑙𝑒𝑡 ·Δx
ΔT
Determination of thermal conductivity and heat capacity
RESULTS AND DISCUSSION. THERMAL ANALYSIS
Thermal conductivity K
Heat Capacity Cp
Cp and K follow a straight line (0.05
and 0.0007 respectively)
Both are representative of those
reported in the literature
y = 0,0548x + 2,8559
y = 0,0007x + 0,0541
0,030
0,040
0,050
0,060
0,070
0,080
0,090
0,100
0
1
2
3
4
5
6
7
8
9
10
0 10 20 30 40 50
Th
erm
al C
on
du
cti
vit
y K
(J/m
·s)
Th
erm
al C
ap
ac
ity C
p (
J/g
·ºC
)
% PCM
Cp(J/g·°C)
K (J/m·s)
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
RESULTS AND DISCUSSION. THERMAL APPLICATIONS
Foam (% PCM) TES (kWh/m3) 0 0.53
10 0.77
20 1.38
30 1.75
40 3.06
50 5.38
1 m3 panels of RPU
(thickness of 3cm)
Standar Room 3x4x2.5 m3
Panels of RPU
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
As example…
RESULTS AND DISCUSSION. THERMAL APPLICATIONS
Consumption of a 60 Watt light bulb = 1.44kWh
Energy saved by a room
covered with panels
containing 50% of
microcapsules
Energy spent by
4 light bulbs
working
all the day
Centro Nacional
de la Energía (CNE)
CO2emitted = 0.35kg/KWh
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
Título presentación
REDUCING THE ENERGY CONSUMPTION IN BUILDINGS BY INCORPORATING MICROENCAPSULATED PCMS
IN RIGID POLYURETHANE FOAMS
THANK YOU FOR YOUR ATTENTION
Reducing the energy consumption in buildings by incorporating microencapsulated PCMs in rigid polyurethane foams
CONCLUSIONS
- It is possible to incorporate up to a 50wt% of mSD-(LDPE-EVA-RT27) into the PU foams,
achieving a homogeneous distribution of the microcapsules and improving the TES capacity of
the foams.
- The higher the microcapsules content, the lower the final foam height. Moreover, the foam
density increases with this content.
- Microcapsules are mechanically stable and they can be found into the strut and also on the cell
wall.
- The higher amount of microcapsules inside the building materials, the higher is the TES
Capacity.
- Thermal capacity and the thermal conductivity follow a straight line, increasing of 0,055 and
0,0007 respectively.
- The incorporation of a 50 wt% of PCMs allows to save up to 5.38KWh/m3, equivalent to
1.44kWh equivalent to the spent energy by 4 light bulbs working all day.
- The incorporation of the mSD-(PEBD·EVA-RT27) into conventional housings will show a great
decrease in the energy consumption and thus in the CO2 emissions.