Research ArticleThermal Performance Analysis of Low-GWP Refrigerants inAutomotive Air-Conditioning System

Yousuf Alhendal 1 Abdalla Gomaa2 Gamal Bedair3 and Abdulrahim Kalendar4

1Mechanical Power and Refrigeration Department (MPR) College of Technological Studies (CTS)Public Authority for Applied Education and Training (PAAET) Adailiya Kuwait2Refrigeration and Air Conditioning Department Faculty of Industrial Education Helwan University Cairo Egypt3Mechanical Department Faculty of Industrial Education Suez University Suez Egypt4College of Technological Studies (CTS) Public Authority for Applied Education and Training (PAAET) Adailiya Kuwait

Correspondence should be addressed to Yousuf Alhendal yaalhendalpaaetedukw

Received 29 October 2019 Accepted 28 December 2019 Published 29 January 2020

Academic Editor HPS Abdul Khalil

Copyright copy 2020 Yousuf Alhendal et al is is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

e energy and exergy of low-global warming potential (GWP) refrigerants were investigated experimentally and theoreticallyRefrigerants with a modest GWP100 of le 150 can be sufficient for bringing down emissions which were concerned for theautomotive air-conditioning systemree types of low-GWP refrigerants R152a R1234yf and R1234ze(E) were examined withparticular reference to the current high-GWP of R134a e effect of different evaporating and condensing temperatures inaddition to compressor speed was considerede purpose was to bring a clear view of the performance characteristics of possibleenvironment friendly alternatives of R134a e analysis was carried out with compressor power cooling capacity coefficient ofperformance exergy destruction and exergy efficiency It was noted that the total exergy destruction of R1234yf was reduced by15 compared to that of R134a e refrigerant R1234ze(E) has the highest energetic and exergetic performance compared withthe other investigated refrigerants

1 Introduction

e greenhouse gases of the refrigerants became the mostissue in scientific research due to their impact on the en-vironment e industrial gases which are released in theenvironment are comparable with CO2 gas which isidentified by a high global warming potential (GWP100)equal to one e gas with a higher value of global warmingpotential warms the earth more than the CO2 gas ecurrent third generation of hydrofluorocarbon refrigerantsin the automotive industry is characterized by a zero ozonedepletion potential and a high global warming potentialwhen released to the atmosphere So there was a great needto find out an alternative to the current R134a(GWP100 1430) under the Kyoto protocol and the Mon-treal protocol [1] Under the agreement of the MontrealProtocol the phasedown of R134a was agreed by a reduction

of the production rate as 7 in 2016 37 in 2018 55 in2021 69 in 2024 and 76 in 2027 with the phaseoutvirtually complete in 2030 [2] From 2017 according to adirective of the European Union automotive manufacturersmanufactures cars with environment-friendly alternativerefrigerants with GWP100le150 In the United States by2020 newly manufactured cars will be equipped with air-conditioning system containing environment friendly re-frigerants with GWP100le150 [2] Globally there are moredemands than ever to reduce greenhouse gases to protect theenvironment and to find out a new generation of envi-ronmentally friendly refrigerants of low GWP which isinvestigated here So the energy and exergy analysis of theautomotive air-conditioning cycle which is based on the firstlaw of thermodynamics to analyze the use of energy and onthe dynamic analysis which is based on the second law ofthermodynamics provides an alternative means of assessing

HindawiAdvances in Materials Science and EngineeringVolume 2020 Article ID 7967812 14 pageshttpsdoiorg10115520207967812

energy efficiency for each part of the refrigeration cycle andcompares operations rationally [3]

Many researchers in the past decade have concernedabout the energy and exergy analysis of the refrigerants witha low global warming potential (GWP100lt 150) according toEuropersquos recommendation Cho and Park [4] studied ex-perimentally the energy and exergy analysis of the refrig-erant R1234yf and compared with R134a used in automotiveair conditioning e experiments were performed with avariable speed compressor and the refrigeration cyclescontained a heat exchanger Both the cooling capacity andthe coefficient of performance of R1234yf were reduced by4ndash7 and 36ndash45 respectively compared with the R134asystem Jemaa et al [5] performed a theoretical study usingthe Engineering Equation Solver (EES) software to analyzethe chiller refrigeration cycle using R1234ze(E) as an al-ternative to R134a Both the energy and exergy were ana-lyzed at different evaporating and ambient temperaturesZhang et al [6] studied the energy and exergy of a zeotropicmixture of R32 and R236fa refrigerants used in a 4 kWchiller e experiments with different concentration ratiosof R32 to R236fa were carried e exergy loss for eachcomponent of the chiller refrigeration cycle was discussed

A review of alternatives to the R134a refrigerant was carriedout by Verma et al [7] From the environmental point of viewthe refrigerant with a low total equivalent warming impactfactor (TEWI) of the investigated alternative refrigerants wasthemost suitable one in a straight drop-in substitute for R134aGarcia et al [8] performed a comparison study of the transientresponse for the R1234yf refrigeration cycle as a replacementfor R134a It was concluded that there was a similar dynamicbehavior between the refrigerants R134a and R1234yf

e performance of the automotive air-conditioning sys-tem for the three types of refrigerants R134a R290 andR1234yf at different operating conditions was studied byNavarro et al [9] It was concluded that a significant im-provement in a compressor and volumetric efficiencies wasobtained with R290 compared with R134a Navarro-Esbrı et al[10] investigated experimentally the R1234yf refrigerant in arefrigeration system as a replacement for R134a at differentevaporating temperatures condensing temperatures andcompressor speeds with and without a heat exchanger erewas a reduction in cooling capacity by 9when comparedwithR134a at the same operating conditions Gomaa [11] carriedout a comparative study between R152a R1234yf andR1234ze(E) with a baseline of R134a in an automotive air-conditioning system It was noted that the performance ofR1234yf was very close to that of R134a when compared withthe performance of R152a and R1234ze(E) respectively eperformance of the R1234yf refrigeration system in automotiveair conditioning was studied by Lee and Jung [12] ey notedthat there was a reduction in COP of the refrigeration systemwith R1234yf by 40 lower than that of R134a

Belman-Flores et al [13] performed an energetic andexergetic study on a domestic refrigerator with R1234yf as areplacement for R134a ey developed a thermodynamiccomputational model which enables to calculate the re-frigeration cycle parameters at different operation condi-tions involving the exergy destruction ratio and exergy

efficiency e exergy destruction was mainly concentratedin the compressor especially for the refrigerants R1234yfand R134a Joybari et al [14] conducted an exergetic studyfor a domestic refrigerator with R134a It was found that thehighest exergy destruction takes place in the compressorfollowed by the condenser capillary tube and evaporator

Sanchez et al [15] presented an experimental study onthe energy performance evaluation of four low-GWP re-frigerants compared with a high GWP of R134a as baselinee four refrigerants R1234yf R1234ze(E) R600a R290 andR152a were tested at different condensing and evaporatingtemperatures Shaik and Ashok Babu [16] performed atheoretical study using theMATLAP code on four low-GWPalternatives of R22 in residential air conditioners ethermodynamic performance of the investigated refrigerantswas compared at different evaporating temperatures Li et al[17] performed a comparative study on energy efficiency ofR717 R600a and R1234yf as low-GWP refrigerants com-pared with R134a in domestic refrigerators ey concludedthat R1234yf has similar performance to R134a which can beconsidered as a drop-in alternative

Vali et al [18] performed an analytical study on the per-formance parameters of a refrigeration system with R22 R32R134a R152a R290 and R1270 From environmental point ofview the R1270 was a more suitable refrigerant to replace R22

In the present study the experimental and theoreticalinvestigation was carried out for three different types of re-frigerants which are considered as one of the most envi-ronmentally friendly refrigerants in automotive airconditioning applications Due to the multiple operatingconditions during the year of the automotive air conditioningthe study was extended to cover a wide range of compressorspeed refrigerant flow rate and evaporating and condensingtemperaturese energetic and exergetic performance with alow-GWP100 equal to 150 or less was the main point of in-terest e low-GWP refrigerants of hydrofluorocarbon(R152a) and the two of a very low-GWP of the fourthgeneration refrigerants which are hydrofluoroolefins ofR1234ze(E) and R1234yf were investigated in this researchwith particular references to the present HFC-R134a (R134a)A weak double bond in hydrofluoroolefin refrigerants allowsfor short atmospheric life [19] while maintaining stability inthe system as illustrated in Figure 1e atmospheric lifetimeof the refrigerants is useful to measure the time it takes toleave the atmosphere as greenhouse gases Table 1 describesthe thermodynamic and environmental properties of theinvestigated refrigerants [19 20]

2 Experimental Setup and Procedure

e experimental test rig comprises of a closed-loop circuitof the R134a refrigeration system a open-loop circuit of theducted air-cooled condenser and a open-loop circuit ofducted air passing through a fin and tube evaporator asshown in Figure 2 e closed-loop refrigeration cycle ofR134a consists of a variable speed semihermetic compressorair-cooled condenser expansion valve liquid receiver filterdrier flowmeter and evaporator To control and vary thecompressor speed a frequency inverter was connected to the

2 Advances in Materials Science and Engineering

electric drive of the compressor e power utilization of thecompressor was measured with a wattmeter having an ac-curacy of plusmn1 e second circuit was the ducted air-cooledcondenser which was equipped with measuring instrumentsto allow measurement of air temperature and velocity on thecondenser airsidee duct was incorporated with a variablespeed axial fan e inlet temperature condition of thecondenser varied according to the heat supplied from theelectric heater which was inserted before the condenser coil

e third open-loop circuit was the duct-containingevaporator e cooled air supplied from the evaporator coilpassed through the duct in which the air duct was equippedwith a variable speed axial fan and an electric heater tocontrol the evaporator load Two voltage regulators wereused to adjust the airspeed and air temperature to a requiredvalue through the evaporator by controlling the voltageacross the DC motor of the fan and the heater respectivelyTwenty thermocouples (type-k) of accuracy plusmn05degC wereinserted upstream and downstream of the evaporator andcondenser respectively in accordance with ASHRAE rec-ommendation A data acquisition system connected to thethermocouples was used to measure the temperaturee airvelocity was measured in both evaporator and condenserducts by a hotwire anemometer with an accuracy of plusmn01e refrigerant flowmeter with an accuracy of plusmn1 was

connected through the refrigeration cycle to measure therefrigerant flow rate at different compressor speeds erefrigerant pressure before and after the compressor wasrecorded with a high- and low-pressure gauge with an ac-curacy of plusmn1

3 Uncertainty Analysis

e implication of the experimental error specifies the errorof the measuring and calculated quantities For the differentparameters the uncertainty analysis was establishedaccording to Holman [21] For independent variables (X1X2 X3 Xn) given Y1 Y2 Y3 Yn uncertainties andWRwas the uncertainty in the result which can be calculated as

YR zR

zX1Y11113888 1113889

2

+zR

zX2Y21113888 1113889

2

+zR

zX3Y31113888 1113889

2

+ middot middot middot +zR

zXn

Yn1113888 1113889

2⎡⎣ ⎤⎦

12

(1)

e uncertainty values of measuring and calculatingparameters are given in Table 2

4 Energy Analysis

e energy balance was a statement of the energy conser-vation law (first law of thermodynamics) while the exergybalance was a statement of the energy degradation (secondlaw of thermodynamics) [22] e representative of ther-modynamic refrigeration cycle is illustrated in Figure 3 inwhich the cooling capacity (Qevap) was given as

Qevap _mref h1 minus h4( 1113857 (2)

in which the refrigerant mass flow rate depends on thevolumetric efficiency stock volume and specific volume ofthe refrigerant at the suction point as

_mref 60 ηv Vth

v1 RPM (3)

e volumetric cooling capacity (VCC) is defined as thecooling capacity per unit refrigerant volume at the exit of theevaporator and it can be calculated as follows

VCC ρ1 h1 minus h4( 1113857 (4)

e compressor power was given by

Wcomp _mref h2 minus h1( 1113857 (5)

At the compressor outlet the actual specific enthalpy ofthe superheated vapor refrigerant (h2) is calculated as

h2 h1 +h2is minus h11113872 1113873

ηiscomp (6)

e isentropic efficiency of the compressor (ηiscomp) wastaken as 065 [23]

e coefficient of performance was defined as

COP Qevap

Wcomp (7)

Table 1 ermodynamic and environmental properties of theinvestigated refrigerants [19 20]

Item R152a R1234yf R1234ze(E) R134aMolecular weight (kgkmol) 66 114 114 102

ASHRAE safetyclassification A2 A2L A2L A1

Critical temperature (degC) 113 95 109 101Boiling point (degC) minus 240 minus 29 minus 19 minus 26Critical pressure (kPa) 4580 3382 3636 4059ODP 0 0 0 0100-year GWP (GWP100) 140 4 6 1430Atmospheric lifetime(years) 06 003 005 14

Hydrofluoroolefin

R1234yf

R1234ze(E)

R134a

HFC HFO

Carbon-carbondouble bond

Hydrofluorocarbon

Figure 1 Atomic bond of the HFC and HFO refrigerants [19]

Advances in Materials Science and Engineering 3

5 Exergy Analysis

Exergy analysis is a method for determining the availabilityof the energy that can be used in a certain system in whichthe deviation of the refrigeration cycle state from a givensituation to the reference situation Exergy analysis is aneffective tool to find out where and how much of the inputenergy of a system was lost e exergy balance was astatement of energy degradation (second law of thermo-dynamics) e following assumptions were considered inthe system exergy analysis

(i) e steady-state conditions were satisfied for allsystem components

(ii) e pressure losses in the pipelines were neglected(iii) e kinetic energy potential energy and exergy

losses were not considered(iv) e heat gain and heat loss from the system were

ignored

A graphical presentation of exergy balance through therefrigeration cycle of the automotive air-conditioning sys-tem is illustrated in Figure 4 e mathematical represen-tative of the exergy (second law analysis) can be expressed as

Emiddot

xdest 1113944Emiddot

xin minus 1113944Emiddot

xout + 1113944 Qmiddot

1 minusTo

T1113874 11138751113890 1113891

in

minus 1113944 Qmiddot

1 minusTo

T1113874 11138751113890 1113891

out+ 1113944 W

middot

in minus 1113944 Wmiddot

out

(8)

e exergy efficiency ηEx is a very useful measure of theextent to which the cycle approaches an ideal behavior eexergy efficiency is the ratio of the actual COP to the max-imum possible COP at the same operating condition [24]

Table 2 Uncertainties of themeasuring instruments and calculatedparameters

Item Uncertainty ()ermocouples (type-k) plusmn21Hotwire anemometer plusmn33Refrigerant flowmeter plusmn29Refrigerant pressure gauge plusmn3Refrigeration capacity plusmn63Compressor power plusmn72COP plusmn56Heat rejection plusmn73Total energy destruction plusmn79

p

3

4

Expansiondevice

Condenser

CompressorEvaporator

h

22is

1

Figure 3 Pressure-enthalpy diagram of the air-conditioning re-frigeration cycle

Thermocouples

Condenser Heater

Filter drier

Liquid receiver

Flowmeter

Expansionvalve

EvaporatorHeater

Voltagecontroller

Voltagecontroller

GPIS

Computer

Fan controller

Fan controller

P

P

T

T

P T

Compressor Electric motor

Variablespeed drive

Figure 2 Schematic diagram of the experimental test rig

4 Advances in Materials Science and Engineering

ηEx Emiddot

xoutEmiddot

xin 1 minus

Emiddot

xdestEmiddot

xin (9)

When the thermodynamic process is reversible the exergyefficiency ηEx 1 and the exergy efficiency lt 1 in other casesermodynamically the exergy in any state was given by

Emiddot

x h minus ho( 1113857 minus To s minus so( 1113857 (10)

e above equations were applied to each thermody-namic process of the refrigeration cycle in which the exergydestruction and efficiency can be expressed as follows

Compressor

Emiddot

xdest Comp Wmiddot

comp + Emiddot

x1 minus Emiddot

x2

ηExComp 1 minusEmiddot

xdest Comp

Wmiddot

in

⎛⎝ ⎞⎠

(11)

Condenser

Emiddot

xdest Cond Emiddot

x2 minus Emiddot

x3

ηExCond 1 minusEmiddot

xdest CondEmiddot

x2 minus Emiddot

x3⎛⎝ ⎞⎠

(12)

Expansion valve

Emiddot

xdest Exp Emiddot

x3 minus Emiddot

x4

ηEx Exp 1 minusEmiddot

x3Emiddot

x4⎛⎝ ⎞⎠

(13)

Evaporator

Emiddot

xdest Evap Emiddot

x4 minus Emiddot

x11113874 1113875 + mmiddot

h1 minus h4( 1113857 1 minusTo

T11113888 11138891113890 1113891

ηExEvap Emiddot

xdest EvapEmiddot

x1 minus Emiddot

x4

(14)

e total energy destruction for all refrigeration cyclecomponents can be expressed as

Emiddot

xdesttotal Emiddot

xdestComp + Emiddot

xdestCond + Emiddot

xdestExp + Emiddot

xdestEvap

(15)

e Engineering Equation Solver [25] software was usedwith the previous equations to develop a solution model ofeach investigated refrigerant with different input parametersat all state points of temperatures and refrigerant mass flowrate corresponding to and similar to that of experiments

6 Results and Discussion

e results of the low-GWP refrigerants in the automotiveair-conditioning system with R134a as baseline were pre-sented as an energetic performance involving cooling ca-pacity compressor power and coefficient of performancefor different compressor speeds and evaporating and con-densing temperatures e exergetic performance is pre-sented in the form of exergy destruction of each cyclecomponent total exergy destruction and exergy efficiency atdifferent cases of refrigerant flow rate and evaporating andcondensing temperatures

61 4e Effect of Varying Compressor RPM e air condi-tioning in the automotive application and in most cases thecompressor is semihermetic which is usually connected tothe engine crankshaft by a belt via two pulleys in which thecompressor RPM varies according to crankshaft RPMwhich in turn affects the refrigerant flow rate e effect ofvarying compressor rotation of R134a on the compressorpower at various condensing temperatures is shown inFigure 5 e compressor power consumption decreaseswith a lower value of the compressor speed and con-densing temperature e ambient air temperature affectsthe compressor power directly As the condensing tem-perature increased by 5degC the compressor power increasedby 13 in which there was an increase in compressorpower by 17 when the RPM of the compressor speedaccelerated by 15 Figure 6 illustrates experimentallyboth the cooling capacity and COP of R134a with thecompressor RPM at various condensing temperatures ecooling capacity increases with the increase of compressorRPM due to the increase in refrigerant mass flow rate Anincrease in the condensing temperature by 5degC led to areduction in the cooling capacity and the COP by 9 and27 respectively e decrease in compressor RPM led toincrease in COP of the refrigeration cycle which can berevealed to the decrease in compressor RPM which yieldedless friction between moving parts and consequently ahigher isentropic efficiency of the compression process wasobtained

e investigation of a wide range of operating conditionson the automotive air-conditioning system with differentrefrigerant types of GWP100lt 150 was studied using Engi-neering Equation Solver software (EES 2017) A validationbetween the experimental and theoretical (EES) results wasperformed at the same operating condition which was in fairagreement erefore the characteristics of the refrigerants

External exergylosses

Internal exergylosses Produced

utilizable exergy

Output exergy

Transiting exergy

Util

izab

le ex

ergy

Con

sum

ed ex

ergy

Inpu

t exe

rgy

Figure 4 Graphical presentation of exergy balance [24]

Advances in Materials Science and Engineering 5

R152a R1234yf and R1234ze(E) were investigated incomparison with a current high-GWP refrigerant of R134a

62 Performance Criteria of Investigated Refrigerants eperformance criteria of the low GWP refrigerants of R152aR1234yf and R1234ze(E) compared with R134a werespecified to the effect of evaporating temperature con-densing temperature and refrigerant flow rate on the en-ergetic and exegetic parameters of the automotive airconditioning system In particular the most possible drop-inreplacement refrigerant to R134a in automotive air condi-tioning application was R152a (GWP100 less 10 times)R1234yf (GWP100 less 358 times) and R1234ze(E) (GWP100less 238 times)

621 4e Effect of Condensing Temperature In particularthe variation of the condensing temperature through the daymonth and season affects the system performance thereforea wide range of condensing temperature 20degCleTcle 45degC wasconsidered Figure 7 illustrates the cooling capacity of dif-ferent refrigerant types at Te 10degC and _V 00031m3s Atthe same operating condition it was noted that a reduction incooling capacity was recorded for R152a R1234yf andR1234ze(E) compared with R134a by 36 38 and 19respectively e compressor power was impacted by

changing of condensing temperature for different refrigeranttypes which is illustrated in Figure 8 At the same operatingcondition the compressor power consumption of R134a washigher than that of R152a R1234yf and R1234ze(E) by 8516 and 28 respectively It has been shown that the re-frigerant R134a has higher values of both refrigeration ca-pacity and compressor power than the proposed refrigerantsat the same operating condition In this case the coefficient ofperformance (COP) is themost important factor to determinethe performance characteristics of the proposed refrigerantswhich is illustrated in Figure 9 e COP of R134a was lowerthan that of R1234ze(E) and R152a by 108 and 56 re-spectively It was confirmed that the COP of the refrigerantR1234yf wasvery close to the performance of R134a in whichthe COP of R134a was higher by 2

e exergy destruction of the system compressor withdifferent condensing temperatures is shown in Figure 10e highest exergy destruction through the compressor wasobtained for R1234yf followed by R134a while R152a has thelowest values of exergy destruction Compared with the baserefrigerant of R134a the compressor exergy destruction ofthe refrigerant R1234ze(E) was higher by 6 while a re-duction in the compressor exergy destruction was obtainedby 14 and 29 for the refrigerants R1234yf and R152arespectively compared with R134a e exergy destructionof the evaporator expansion valve and condenser was alsocalculated to form the total exergy destructione variationof the total exergy destruction of all refrigeration cyclecomponents with the condensing temperature is illustrated

0

1

2

3

4

5

6

7

8

0

1

2

3

4

5

6

7

8

9

10

0 500 1000 1500 2000RPM

Qevap Tc = 25degCQevap Tc = 35degCQevap Tc = 45degC

COP Tc = 25degCCOP Tc = 35degCCOP Tc = 45degC

COP

Qev

a (kW

)

Figure 6 Cooling capacity and COP versus RPM of R134a (ex-perimental results)

0 300 600 900 1200 1500 1800RPM

3

25

2

15

1

05

0

Pow

er (k

W)

Tc = 25degCTc = 30degCTc = 35degC

Tc = 40degCTc = 45degC

Figure 5 Compressor power versus RPM of R134a (experimentalresults)

6 Advances in Materials Science and Engineering

in Figure 11 e total exergy destruction of R1234yf andR1234ze(E) was quite similar in which the total exergydestruction of both refrigerants were higher than that ofR134a by 12 while the total exergy destruction of R152awas lower than that of R134a by 26

e effect of varying condensing temperature on theenergy and exergy parameters is summarized as a sample ofresults in Table 3

622 4e Effect of Evaporating Temperature e evapo-rating temperature was different from one application toanother and it should be noted that the evaporating tem-perature affects the system performance positively A widerange of evaporating temperatures which were applied inmany air conditioning applications (minus 15degC to 15degC) wastested for different refrigerant types of R134a R152aR124yf and R1234ze(E) e compressor power con-sumption was influenced by varying evaporating tempera-ture for all investigated refrigerants as illustrated inFigure 12 Although the enthalpy difference (h2 minus h1) inEquation (4) decreases as the evaporating temperature in-creases the values of the compressor power increase as theevaporating temperature increases is can be explained onthe basis of equations (2) and (4) where the enthalpy dif-ference (h2 minus h1) decreases with the increase in the evapo-rating temperature while the volumetric efficiency increasesand the specific volume decreases in accordance with

0

05

1

15

2

25

3

15 20 25 30 35 40 45 50

Pow

er (k

W)

Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 8 Effect of condensing temperature on compressor powerfor investigated refrigerants

1

2

3

4

5

6

7

8

15 20 25 30 35 40 45 50

COP

Tc (degC)

Te = 10degCV = 00031m3s

R134aR152a

R1234yfR1234ze(E)

Figure 9 Effect of condensing temperature on COP for investi-gated refrigerants

2

3

4

5

6

7

8

9

10

15 20 25 30 35 40 45 50

R134aR152a

R1234yfR1234ze(E)

Coo

ling

capa

city

(kW

)

Tc (degC)

Figure 7 Effect of condensing temperature on cooling capacity forinvestigated refrigerants

Advances in Materials Science and Engineering 7

Equation (2) is led to an increase in mass flow rate beinggreater than the decrease in the enthalpy difference (h2 minus h1)and consequently the compressor power consumption in-creases with evaporating temperature is trend curveconfirmed with Li et al [17] and Llopis et al [26]

e compressor power of R134a and R1234yf was quitesimilar A reduction in a compressor power for R152a andR1234ze(E) by 8 and 26 respectively was occurred whencompared with R134a

ere are two important parameters that can charac-terize the most appropriate alternative refrigerants toR134a volumetric cooling capacity and discharge tem-perature Figure 13 illustrates the volumetric refrigerationcapacity (VCC) and the discharge temperature versus theevaporating temperature for all investigated refrigerantse volumetric refrigeration capacity expresses the coolingcapacity per unit volume at the exit of the evaporator Itindicates the volume of refrigerants handled by the com-pressor It was noted that R134a has the highest volumetriccooling capacity followed by R152a and R1234yf while theR1234ze(E) has lowest values of volumetric cooling ca-pacity is mean that the refrigerants R152a and R1234yfcan be replaced by R134a on the same compressor size inwhich the refrigerant R1234ze(E) needs to resize thecompressor for a given duty

It is necessary to study the discharge temperature for thelow-GWP refrigerant compared with R134a in order toclarify the steadiness and lifetime of the compressor

Referring to Figure 13 which illustrates the dischargetemperature versus the evaporating temperature for all in-vestigated refrigerants it was noted that the refrigerantR152a has the highest discharge temperature and it isimpediment in replacement between R152a and R134awhile the discharge temperature of R1234ze(E) and R1234yfis lower than that of R134a which is considered an advantagein replacement between R1234ze(E) R1234yf and R134a

e changing of the evaporating temperature affects theCOP of the system positively which is illustrated in Figure 14As the evaporating temperature increased the COP of therefrigeration system increased which can be attributed to theincrease in cooling capacity and was more rapid than theincrease in compressor powere refrigerant R1234ze(E) hasthe highest values of the COP among all the investigatedrefrigerants It was confirmed that the thermal performance ofthe R1234yf refrigerant (GWP100 358 times less than that ofR134a) was the closest to the thermal performance of theR134a system and therefore a more environmentally sus-tainable refrigerant for automotive air conditioning

e exergy destruction for the system compressor withdifferent evaporating temperatures is illustrated in Figure 15e highest exergy destruction through the compressor wasobtained for R1234ze(E) followed by R134a while R152a hasthe lowest values of exergy destruction Compared with thebase refrigerant of R134a the compressor exergy destructionof the refrigerant R1234ze(E) was higher by 65 while thecompressor exergy destruction of R1234yf and R152a wasreduced by 11 and 40 respectively e total exergy

0

02

04

06

08

1

12

E tot

al (k

W)

15 20 25 30 35 40 45 50Tc (degC)

Te = 10degCV = 00031m3s

R134aR152a

R1234yfR1234ze(E)

Figure 11 Total exergy destruction versus condensing temperature

005

01

015

02

025

03

035

04

15 20 25 30 35 40 45 50

E com

p (k

W)

Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degCV = 00031m3s

Figure 10 Exergy destruction in compressor versus condensingtemperature

8 Advances in Materials Science and Engineering

destruction of the all-cycle components for different types ofrefrigerants and the evaporating temperature is illustrated inFigure 16 e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the total exergydestruction of R1234yf and R152a was lower than that ofR134a by 15 and 45 respectively

623 4e Effect of Refrigerant Flow Rate e refrigerantvolume flow rate variation which was produced as a result ofvarying compressor speed which in turn was originated fromautomotive crankshaft speed affects the performance of theautomotive air conditioninge effect of varying volume flowrate on the cooling capacity and the coefficient of performanceis illustrated in Figures 17 and 18 for a typical condition ofTe 10degC and Tc 35degC e refrigerant mass flow rate variedas the RPM of the crankshaft was changed which depend on

Table 3 Results of the investigated refrigerants at different condensing temperatures

Item Tc oC R152a R1234yf R1234ze(E) R134a

Cooling capacity

30 660 669 561 69035 644 638 538 66540 624 606 515 63945 604 573 491 612

Compressor power

30 158 169 125 17135 1774 190 143 19440 1984 211 160 21545 2191 231 177 237

COP

30 418 396 447 40335 363 336 377 34440 315 288 322 29745 276 248 278 258

Total exergy destruction Etotal

30 0549 0851 0845 074835 0530 0812 0821 073040 0524 0780 0801 071045 0532 0770 0797 0701

Total exergy efficiency ηtotal

30 0322 028 0357 03435 0299 026 0336 03240 027 025 031 0345 0255 024 029 028

0

05

1

15

2

25

3

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Pow

er (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 12 Compressor power versus evaporating temperature

Disc

harg

e tem

pera

ture

(degC)

0

20

40

60

80

100

120

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Vol

umet

ric co

olin

g ca

paci

ty (k

Jm3 )

Te (degC)

VCC R134aVCC R152VCC R1234yfVCC R1234ze

Tdis R134aTdis R152aTdis R1234yfTdis R1234ze(E)

Figure 13 Effect of evaporating temperature on volumetriccooling capacity and discharge temperature

Advances in Materials Science and Engineering 9

the rate of fuel consumption of the automotive engine Inpractice the refrigerant mass flow rate ( _m ρ _v) which is therefrigerant density multiplied by volume flow rate affects thecooling capacity and compressor power according to equa-tions (1) and (2) in which the density varies according tovariation in evaporating temperature erefore the influenceof the refrigerant flow rate was evident to the coefficient ofperformance As the refrigerant flow rate increases the COPdecreases which can be explained by the increase in com-pressor power with a flow rate greater than the increase incooling capacity It is noted that the refrigerant R1234ze(E) hasthe highest COP between investigated refrigerants

e total exergy destruction of the compressor con-denser expansion valve and evaporator for the differentrefrigerant types is illustrated in Figure 19 e highestexergy destruction of the compressor was obtained forR1234ze(E) and the highest exergy destruction of thecondenser was obtained for R1234fy while the lowest valueof exergy destruction for the compressor and condenser wasobtained for R152a e highest values of the exergy de-struction for the evaporator and expansion valve were ob-tained for R1234ze(E) and R1234fy respectively

Exergy efficiency can give more logical ways to improvethe energy performance of automotive air conditioning Forthat reason the exergy analysis which was performed foreach cycle component should be considered integrated [6]Figures 20 and 21 show the total exergy efficiency with both

1

2

3

4

5

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

COP

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 14 COP versus evaporating temperature for Tc 35degC

005

01

015

02

025

03

035

04

ndash15 ndash10 ndash5 0 5 10 15 20

E com

p (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 15 Exergy destruction in compressor versus evaporatingtemperature

0

01

02

03

04

05

06

07

08

09

1

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

E tot

al

Figure 16 Total exergy destruction versus evaporatingtemperature

10 Advances in Materials Science and Engineering

0

1

2

3

4

5

6

7

8

0 05 1 15 2 25 3 35

Cool

ing

capa

city

(kW

)

V lowast 103 (m3s)

R134aR152a

R1234yfR1234ze(E)

Figure 17 Cooling capacity versus refrigerant flow rate at Tc 35degC

1

2

3

4

5

6

0 05 1 15 2 25 3 35

COP

R134aR152a

R1234yfR1234ze(E)

V lowast 103 (m3s)

Figure 18 COP versus refrigerant volume flow rate

Advances in Materials Science and Engineering 11

condensing and evaporating temperatures e total exergyefficiency was decreased with the condensing temperaturewhile it was increased with the evaporating temperature For

both condensing and evaporating temperatures the re-frigerant R1234yf has the lowest exergy efficiency followedby R152a e highest exergy efficiency was obtained withR1234ze(E) at different condensing temperatures while atdifferent evaporating temperatures the highest exergy effi-ciency was obtained for R134a From the environmentalthermal and exergy point of view the refrigerant R1234yfhas the best performance among all refrigerants that havebeen investigated to replace R134a in an automotive air-conditioning system

7 Conclusion

Energy and exergy analysis was presented for many envi-ronmentally friendly refrigerants as a drop-in replacementof current high-GWP of R134a in the automotive air-con-ditioning system ree alternative refrigerants which isdistinguished by zero ODP and GWP100lt 150 were inves-tigated with particular reference to the current R134a re-frigerant (GWP100 1430) e exergy destruction of eachcomponent and the exergy efficiency at different condensingtemperatures evaporating temperatures and refrigerantflow rates were presented and the main conclusions aresummarized as follows

(i) For all values of condensing and evaporatingtemperatures a higher system COP was obtained at

01

02

03

04

05

06

07

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degC V = 00031m3s

η tot

al

Figure 20 Total exergy efficiency versus condensing temperature

0

01

02

03

04

05

06

15 20 25 30 35 40 45 50Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degC V = 00031m3s

η tot

al

Figure 21 Total exergy efficiency versus evaporating temperature

R134a R152a R1234yf R1234ze

030

025

020

015

010

005

000

CompressorCondenser

ExpansionEvaporator

Figure 19 Total exergy destruction of each component for dif-ferent refrigerant types

12 Advances in Materials Science and Engineering

a lower compressor speed which was producedfrom slow crankshaft RPM

(ii) A reduction in the cooling capacity by 9 and inCOP by 27 was confirmed when a condensingtemperature increased by 5degC

(iii) Based on the test results the refrigerant R1234ze(E)had the highest coefficient of performance amongall investigated refrigerants

(iv) e refrigerant R1234yf was considered the closestin thermal performance to the refrigerant R134a

(v) e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the totalexergy destruction of R1234yf and R152a was lowerthan that of R134a by 15 and 45 respectively

(vi) e refrigerant R1234ze(E) was the most envi-ronmentally acceptable and had the best energeticand exergetic performance among all the testedrefrigerants

(vii) e highest exergy efficiency was obtained forR1234ze(E) at different condensing temperatureswhile at different evaporating temperatures thehighest exergy efficiency was obtained for R134a

Nomenclature

COP coefficient of performanceCP specific heat kJkgmiddotKEmiddot

x exergy kWh specific enthalpy kJkg_mref refrigerant flow rate kgsp refrigerant pressure kPaQ rate of heat transfer kWRPM revolution per minute minminus 1

s entropy kJkgmiddotKT temperature K_V refrigerant flow rate m3sVCC volumetric cooling capacity kJm3

W compressor power kWGWP100 global warming potential for 100 yearsΡ density kgm3

c coolingcomp compressorcond condenserexp expansionevap evaporatordest destructiondis dischargein inletis isentropicmech mechanicalo dead stateout outlet

Data Availability

e data that support the findings of this study are availableupon request from the corresponding author

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e authors would like to express their sincere gratitude tothe Public Authority for Applied Education and Training(PAAET) Kuwait for supporting and funding this workResearch Project No TS -16-12 Research Project TitleldquoEnergetic and exergetic analysis of R1234yf R1234ze andR152 as a low-GWP alternatives of R134a in automotive airconditioningrdquo Special appreciation to Refrigeration and AirConditioning Department Faculty of Industrial EducationHelwan University Egypt for the technical assistance ex-tended to the authors

References

[1] I P Koronaki D Cowan G Maidment et al ldquoRefrigerantemissions and leakage prevention across Europemdashresultsfrom the real skills Europe projectrdquo Energy vol 45 no 1pp 71ndash80 2012

[2] Environmental Protection Agency Protection of StratosphericOzone Change of Listing Status for Certain Substitutes underthe Significant New Alternatives Policy Program Rules andRegulations Environmental Protection Agency EPAWashington DC USA 2015

[3] I Dincer and A R Marc Exergy Energy Environment andSustainable Development Elsevier Amsterdam NetherlandsSecond edition 2016

[4] H Cho and C Park ldquoExperimental investigation of perfor-mance and exergy analysis of automotive air conditioningsystems using refrigerant R1234yf at various compressorspeedsrdquo Applied 4ermal Engineering vol 101 pp 30ndash372016

[5] B Jemaa R Mansouri I Boukholda and A Bellagi ldquoEnergyand exergy investigation of R1234ze(E) as R134a replacementin vapor compression chillersrdquo International Journal of Hy-drogen Energy vol 42 no 17 pp 12877ndash12887 2017

[6] K Zhang Y Zhu J Liu X Niu and X Yuan ldquoExergy andenergy analysis of a double evaporating temperature chillerrdquoEnergy and Buildings vol 165 pp 464ndash471 2018

[7] J K Verma A Satsangi and V Chaturani ldquoA review ofalternative to R134a (CH3CH2F) refrigerantrdquo InternationalJournal of Emerging Technology and Advanced Engineeringvol 3 no 1 pp 300ndash304 2013

[8] J Garcia T Ali W M Duarte A Khosravi and L MachadoldquoComparison of transient response of an evaporatormodel forwater refrigeration system working with R1234yf as a drop-inreplacement for R134ardquo International Journal of Refrigera-tion vol 91 pp 211ndash222 2018

[9] E Navarro I O Martınez-Galvan J Nohales andJ Gonzalvez-Macia ldquoComparative experimental study of anopen piston compressor working with R-1234yf R-134a andR-290rdquo International Journal of Refrigeration vol 36 no 3pp 768ndash775 2013

[10] J Navarro-Esbrı J M Mendoza-Miranda A Mota-BabiloniA Barraga-Cervera A Barragan-Cervera and J M Belman-Flores ldquoExperimental analysis of R1234yf as a drop-in re-placement for R134a in a vapor compression systemrdquo In-ternational Journal of Refrigeration vol 36 no 3pp 870ndash880 2013

Advances in Materials Science and Engineering 13

[11] A Gomaa ldquoPerformance characteristics of automotive airconditioning system with refrigerant R134a and its alterna-tivesrdquo International Journal of Energy and Power Engineeringvol 4 no 3 pp 168ndash177 2015

[12] Y Lee and D Jung ldquoA brief performance comparison ofR1234yf and R134a in a bench tester for automobile appli-cationsrdquo Applied 4ermal Engineering vol 35 pp 240ndash2422012

[13] J M Belman-Flores V H Rangel-Hernandez S Uson andC Rubio-Maya ldquoEnergy and exergy analysis of R1234yf asdrop-in replacement for R134a in a domestic refrigerationsystemrdquo Energy vol 132 pp 116ndash125 2017

[14] M Joybari M H Hatamipour A Rahimi and F ModarresldquoExergy analysis and optimization of R600a as a replacementof R134a in a domestic refrigerator systemrdquo InternationalJournal of Refrigeration vol 36 no 4 pp 1233ndash1242 2013

[15] D Sanchez R Cabello R Llopis I Arauzo J Catalan-Giland E Torrella ldquoEnergy performance evaluation of R1234yfR1234ze(E) R600a R290 and R152a as low-GWP R134aalternativesrdquo International Journal of Refrigeration vol 74pp 269ndash282 2017

[16] S V Shaik and T P Ashok Babu ldquoeoretical computation ofperformance of sustainable energy efficient R22 alternativesfor residential air conditionersrdquo Energy Procedia vol 138pp 710ndash716 2017

[17] Z Li H Jiang X Chen and K Liang ldquoComparative study onenergy efficiency of low GWP refrigerants in domestic re-frigerators with capacity modulationrdquo Energy and Buildingsvol 192 pp 93ndash100 2019

[18] S S Vali T P Setty and A Babu ldquoAnalytical computation ofthermodynamic performance parameters of actual vapourcompression refrigeration system with R22 R32 R134aR152a R290 and R1270rdquo MATEC Web of Conferencesvol 144 Article ID 04009 2018

[19] G Relue and S Kopchick New Refrigerants Designation andSafety Classifications E360 Forum Emerson Raleigh NCUSA 2017

[20] ASHRAE Standard 34Designation and Safety Classification ofRefrigerants American Society of Heating Ventilating andAir-Conditioning Engineers Atlanta GA USA 2010

[21] J P Holman Experimental Method for Engineerspp 62ndash65McGraw-Hill Book Company New York NY USA Eighthedition 2001

[22] B O Bolaji ldquoExperimental study of R152a and R32 to replaceR134a in a domestic refrigeratorrdquo Energy vol 35 no 9pp 3793ndash3798 2010

[23] M Fatouh A I Eid and N Nabil ldquoPerformance of water-to-water vapor compression refrigeration system using R22 al-ternatives part I system simulationrdquo Engineering ResearchJournal vol 124 pp M19ndashM43 2009

[24] A Yataganbaba A Kilicarslan and I Kurtbas ldquoExergyanalysis of R1234yf and R1234ze as R134a replacements in atwo evaporator vapour compression refrigeration systemrdquoInternational Journal of Refrigeration vol 60 pp 26ndash37 2015

[25] G F Nellis and S A Klein Engineering Equation Solver (EES)F-Chart Software Wiley Middleton WI USA 2013

[26] R Llopis E Torrella R Cabello and D Sanchez ldquoPerfor-mance evaluation of R404A and R507A refrigerant mixturesin an experimental double-stage vapour compression plantrdquoApplied Energy vol 87 no 5 pp 1546ndash1553 2010

14 Advances in Materials Science and Engineering

electric drive of the compressor e power utilization of thecompressor was measured with a wattmeter having an ac-curacy of plusmn1 e second circuit was the ducted air-cooledcondenser which was equipped with measuring instrumentsto allow measurement of air temperature and velocity on thecondenser airsidee duct was incorporated with a variablespeed axial fan e inlet temperature condition of thecondenser varied according to the heat supplied from theelectric heater which was inserted before the condenser coil

e third open-loop circuit was the duct-containingevaporator e cooled air supplied from the evaporator coilpassed through the duct in which the air duct was equippedwith a variable speed axial fan and an electric heater tocontrol the evaporator load Two voltage regulators wereused to adjust the airspeed and air temperature to a requiredvalue through the evaporator by controlling the voltageacross the DC motor of the fan and the heater respectivelyTwenty thermocouples (type-k) of accuracy plusmn05degC wereinserted upstream and downstream of the evaporator andcondenser respectively in accordance with ASHRAE rec-ommendation A data acquisition system connected to thethermocouples was used to measure the temperaturee airvelocity was measured in both evaporator and condenserducts by a hotwire anemometer with an accuracy of plusmn01e refrigerant flowmeter with an accuracy of plusmn1 was

connected through the refrigeration cycle to measure therefrigerant flow rate at different compressor speeds erefrigerant pressure before and after the compressor wasrecorded with a high- and low-pressure gauge with an ac-curacy of plusmn1

3 Uncertainty Analysis

e implication of the experimental error specifies the errorof the measuring and calculated quantities For the differentparameters the uncertainty analysis was establishedaccording to Holman [21] For independent variables (X1X2 X3 Xn) given Y1 Y2 Y3 Yn uncertainties andWRwas the uncertainty in the result which can be calculated as

YR zR

zX1Y11113888 1113889

2

+zR

zX2Y21113888 1113889

2

+zR

zX3Y31113888 1113889

2

+ middot middot middot +zR

zXn

Yn1113888 1113889

2⎡⎣ ⎤⎦

12

(1)

e uncertainty values of measuring and calculatingparameters are given in Table 2

4 Energy Analysis

e energy balance was a statement of the energy conser-vation law (first law of thermodynamics) while the exergybalance was a statement of the energy degradation (secondlaw of thermodynamics) [22] e representative of ther-modynamic refrigeration cycle is illustrated in Figure 3 inwhich the cooling capacity (Qevap) was given as

Qevap _mref h1 minus h4( 1113857 (2)

in which the refrigerant mass flow rate depends on thevolumetric efficiency stock volume and specific volume ofthe refrigerant at the suction point as

_mref 60 ηv Vth

v1 RPM (3)

e volumetric cooling capacity (VCC) is defined as thecooling capacity per unit refrigerant volume at the exit of theevaporator and it can be calculated as follows

VCC ρ1 h1 minus h4( 1113857 (4)

e compressor power was given by

Wcomp _mref h2 minus h1( 1113857 (5)

At the compressor outlet the actual specific enthalpy ofthe superheated vapor refrigerant (h2) is calculated as

h2 h1 +h2is minus h11113872 1113873

ηiscomp (6)

e isentropic efficiency of the compressor (ηiscomp) wastaken as 065 [23]

e coefficient of performance was defined as

COP Qevap

Wcomp (7)

Table 1 ermodynamic and environmental properties of theinvestigated refrigerants [19 20]

Item R152a R1234yf R1234ze(E) R134aMolecular weight (kgkmol) 66 114 114 102

ASHRAE safetyclassification A2 A2L A2L A1

Critical temperature (degC) 113 95 109 101Boiling point (degC) minus 240 minus 29 minus 19 minus 26Critical pressure (kPa) 4580 3382 3636 4059ODP 0 0 0 0100-year GWP (GWP100) 140 4 6 1430Atmospheric lifetime(years) 06 003 005 14

Hydrofluoroolefin

R1234yf

R1234ze(E)

R134a

HFC HFO

Carbon-carbondouble bond

Hydrofluorocarbon

Figure 1 Atomic bond of the HFC and HFO refrigerants [19]

Advances in Materials Science and Engineering 3

5 Exergy Analysis

Exergy analysis is a method for determining the availabilityof the energy that can be used in a certain system in whichthe deviation of the refrigeration cycle state from a givensituation to the reference situation Exergy analysis is aneffective tool to find out where and how much of the inputenergy of a system was lost e exergy balance was astatement of energy degradation (second law of thermo-dynamics) e following assumptions were considered inthe system exergy analysis

(i) e steady-state conditions were satisfied for allsystem components

(ii) e pressure losses in the pipelines were neglected(iii) e kinetic energy potential energy and exergy

losses were not considered(iv) e heat gain and heat loss from the system were

ignored

A graphical presentation of exergy balance through therefrigeration cycle of the automotive air-conditioning sys-tem is illustrated in Figure 4 e mathematical represen-tative of the exergy (second law analysis) can be expressed as

Emiddot

xdest 1113944Emiddot

xin minus 1113944Emiddot

xout + 1113944 Qmiddot

1 minusTo

T1113874 11138751113890 1113891

in

minus 1113944 Qmiddot

1 minusTo

T1113874 11138751113890 1113891

out+ 1113944 W

middot

in minus 1113944 Wmiddot

out

(8)

e exergy efficiency ηEx is a very useful measure of theextent to which the cycle approaches an ideal behavior eexergy efficiency is the ratio of the actual COP to the max-imum possible COP at the same operating condition [24]

Table 2 Uncertainties of themeasuring instruments and calculatedparameters

Item Uncertainty ()ermocouples (type-k) plusmn21Hotwire anemometer plusmn33Refrigerant flowmeter plusmn29Refrigerant pressure gauge plusmn3Refrigeration capacity plusmn63Compressor power plusmn72COP plusmn56Heat rejection plusmn73Total energy destruction plusmn79

p

3

4

Expansiondevice

Condenser

CompressorEvaporator

h

22is

1

Figure 3 Pressure-enthalpy diagram of the air-conditioning re-frigeration cycle

Thermocouples

Condenser Heater

Filter drier

Liquid receiver

Flowmeter

Expansionvalve

EvaporatorHeater

Voltagecontroller

Voltagecontroller

GPIS

Computer

Fan controller

Fan controller

P

P

T

T

P T

Compressor Electric motor

Variablespeed drive

Figure 2 Schematic diagram of the experimental test rig

4 Advances in Materials Science and Engineering

ηEx Emiddot

xoutEmiddot

xin 1 minus

Emiddot

xdestEmiddot

xin (9)

When the thermodynamic process is reversible the exergyefficiency ηEx 1 and the exergy efficiency lt 1 in other casesermodynamically the exergy in any state was given by

Emiddot

x h minus ho( 1113857 minus To s minus so( 1113857 (10)

e above equations were applied to each thermody-namic process of the refrigeration cycle in which the exergydestruction and efficiency can be expressed as follows

Compressor

Emiddot

xdest Comp Wmiddot

comp + Emiddot

x1 minus Emiddot

x2

ηExComp 1 minusEmiddot

xdest Comp

Wmiddot

in

⎛⎝ ⎞⎠

(11)

Condenser

Emiddot

xdest Cond Emiddot

x2 minus Emiddot

x3

ηExCond 1 minusEmiddot

xdest CondEmiddot

x2 minus Emiddot

x3⎛⎝ ⎞⎠

(12)

Expansion valve

Emiddot

xdest Exp Emiddot

x3 minus Emiddot

x4

ηEx Exp 1 minusEmiddot

x3Emiddot

x4⎛⎝ ⎞⎠

(13)

Evaporator

Emiddot

xdest Evap Emiddot

x4 minus Emiddot

x11113874 1113875 + mmiddot

h1 minus h4( 1113857 1 minusTo

T11113888 11138891113890 1113891

ηExEvap Emiddot

xdest EvapEmiddot

x1 minus Emiddot

x4

(14)

e total energy destruction for all refrigeration cyclecomponents can be expressed as

Emiddot

xdesttotal Emiddot

xdestComp + Emiddot

xdestCond + Emiddot

xdestExp + Emiddot

xdestEvap

(15)

e Engineering Equation Solver [25] software was usedwith the previous equations to develop a solution model ofeach investigated refrigerant with different input parametersat all state points of temperatures and refrigerant mass flowrate corresponding to and similar to that of experiments

6 Results and Discussion

e results of the low-GWP refrigerants in the automotiveair-conditioning system with R134a as baseline were pre-sented as an energetic performance involving cooling ca-pacity compressor power and coefficient of performancefor different compressor speeds and evaporating and con-densing temperatures e exergetic performance is pre-sented in the form of exergy destruction of each cyclecomponent total exergy destruction and exergy efficiency atdifferent cases of refrigerant flow rate and evaporating andcondensing temperatures

61 4e Effect of Varying Compressor RPM e air condi-tioning in the automotive application and in most cases thecompressor is semihermetic which is usually connected tothe engine crankshaft by a belt via two pulleys in which thecompressor RPM varies according to crankshaft RPMwhich in turn affects the refrigerant flow rate e effect ofvarying compressor rotation of R134a on the compressorpower at various condensing temperatures is shown inFigure 5 e compressor power consumption decreaseswith a lower value of the compressor speed and con-densing temperature e ambient air temperature affectsthe compressor power directly As the condensing tem-perature increased by 5degC the compressor power increasedby 13 in which there was an increase in compressorpower by 17 when the RPM of the compressor speedaccelerated by 15 Figure 6 illustrates experimentallyboth the cooling capacity and COP of R134a with thecompressor RPM at various condensing temperatures ecooling capacity increases with the increase of compressorRPM due to the increase in refrigerant mass flow rate Anincrease in the condensing temperature by 5degC led to areduction in the cooling capacity and the COP by 9 and27 respectively e decrease in compressor RPM led toincrease in COP of the refrigeration cycle which can berevealed to the decrease in compressor RPM which yieldedless friction between moving parts and consequently ahigher isentropic efficiency of the compression process wasobtained

e investigation of a wide range of operating conditionson the automotive air-conditioning system with differentrefrigerant types of GWP100lt 150 was studied using Engi-neering Equation Solver software (EES 2017) A validationbetween the experimental and theoretical (EES) results wasperformed at the same operating condition which was in fairagreement erefore the characteristics of the refrigerants

External exergylosses

Internal exergylosses Produced

utilizable exergy

Output exergy

Transiting exergy

Util

izab

le ex

ergy

Con

sum

ed ex

ergy

Inpu

t exe

rgy

Figure 4 Graphical presentation of exergy balance [24]

Advances in Materials Science and Engineering 5

R152a R1234yf and R1234ze(E) were investigated incomparison with a current high-GWP refrigerant of R134a

62 Performance Criteria of Investigated Refrigerants eperformance criteria of the low GWP refrigerants of R152aR1234yf and R1234ze(E) compared with R134a werespecified to the effect of evaporating temperature con-densing temperature and refrigerant flow rate on the en-ergetic and exegetic parameters of the automotive airconditioning system In particular the most possible drop-inreplacement refrigerant to R134a in automotive air condi-tioning application was R152a (GWP100 less 10 times)R1234yf (GWP100 less 358 times) and R1234ze(E) (GWP100less 238 times)

621 4e Effect of Condensing Temperature In particularthe variation of the condensing temperature through the daymonth and season affects the system performance thereforea wide range of condensing temperature 20degCleTcle 45degC wasconsidered Figure 7 illustrates the cooling capacity of dif-ferent refrigerant types at Te 10degC and _V 00031m3s Atthe same operating condition it was noted that a reduction incooling capacity was recorded for R152a R1234yf andR1234ze(E) compared with R134a by 36 38 and 19respectively e compressor power was impacted by

changing of condensing temperature for different refrigeranttypes which is illustrated in Figure 8 At the same operatingcondition the compressor power consumption of R134a washigher than that of R152a R1234yf and R1234ze(E) by 8516 and 28 respectively It has been shown that the re-frigerant R134a has higher values of both refrigeration ca-pacity and compressor power than the proposed refrigerantsat the same operating condition In this case the coefficient ofperformance (COP) is themost important factor to determinethe performance characteristics of the proposed refrigerantswhich is illustrated in Figure 9 e COP of R134a was lowerthan that of R1234ze(E) and R152a by 108 and 56 re-spectively It was confirmed that the COP of the refrigerantR1234yf wasvery close to the performance of R134a in whichthe COP of R134a was higher by 2

e exergy destruction of the system compressor withdifferent condensing temperatures is shown in Figure 10e highest exergy destruction through the compressor wasobtained for R1234yf followed by R134a while R152a has thelowest values of exergy destruction Compared with the baserefrigerant of R134a the compressor exergy destruction ofthe refrigerant R1234ze(E) was higher by 6 while a re-duction in the compressor exergy destruction was obtainedby 14 and 29 for the refrigerants R1234yf and R152arespectively compared with R134a e exergy destructionof the evaporator expansion valve and condenser was alsocalculated to form the total exergy destructione variationof the total exergy destruction of all refrigeration cyclecomponents with the condensing temperature is illustrated

0

1

2

3

4

5

6

7

8

0

1

2

3

4

5

6

7

8

9

10

0 500 1000 1500 2000RPM

Qevap Tc = 25degCQevap Tc = 35degCQevap Tc = 45degC

COP Tc = 25degCCOP Tc = 35degCCOP Tc = 45degC

COP

Qev

a (kW

)

Figure 6 Cooling capacity and COP versus RPM of R134a (ex-perimental results)

0 300 600 900 1200 1500 1800RPM

3

25

2

15

1

05

0

Pow

er (k

W)

Tc = 25degCTc = 30degCTc = 35degC

Tc = 40degCTc = 45degC

Figure 5 Compressor power versus RPM of R134a (experimentalresults)

6 Advances in Materials Science and Engineering

in Figure 11 e total exergy destruction of R1234yf andR1234ze(E) was quite similar in which the total exergydestruction of both refrigerants were higher than that ofR134a by 12 while the total exergy destruction of R152awas lower than that of R134a by 26

e effect of varying condensing temperature on theenergy and exergy parameters is summarized as a sample ofresults in Table 3

622 4e Effect of Evaporating Temperature e evapo-rating temperature was different from one application toanother and it should be noted that the evaporating tem-perature affects the system performance positively A widerange of evaporating temperatures which were applied inmany air conditioning applications (minus 15degC to 15degC) wastested for different refrigerant types of R134a R152aR124yf and R1234ze(E) e compressor power con-sumption was influenced by varying evaporating tempera-ture for all investigated refrigerants as illustrated inFigure 12 Although the enthalpy difference (h2 minus h1) inEquation (4) decreases as the evaporating temperature in-creases the values of the compressor power increase as theevaporating temperature increases is can be explained onthe basis of equations (2) and (4) where the enthalpy dif-ference (h2 minus h1) decreases with the increase in the evapo-rating temperature while the volumetric efficiency increasesand the specific volume decreases in accordance with

0

05

1

15

2

25

3

15 20 25 30 35 40 45 50

Pow

er (k

W)

Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 8 Effect of condensing temperature on compressor powerfor investigated refrigerants

1

2

3

4

5

6

7

8

15 20 25 30 35 40 45 50

COP

Tc (degC)

Te = 10degCV = 00031m3s

R134aR152a

R1234yfR1234ze(E)

Figure 9 Effect of condensing temperature on COP for investi-gated refrigerants

2

3

4

5

6

7

8

9

10

15 20 25 30 35 40 45 50

R134aR152a

R1234yfR1234ze(E)

Coo

ling

capa

city

(kW

)

Tc (degC)

Figure 7 Effect of condensing temperature on cooling capacity forinvestigated refrigerants

Advances in Materials Science and Engineering 7

Equation (2) is led to an increase in mass flow rate beinggreater than the decrease in the enthalpy difference (h2 minus h1)and consequently the compressor power consumption in-creases with evaporating temperature is trend curveconfirmed with Li et al [17] and Llopis et al [26]

e compressor power of R134a and R1234yf was quitesimilar A reduction in a compressor power for R152a andR1234ze(E) by 8 and 26 respectively was occurred whencompared with R134a

ere are two important parameters that can charac-terize the most appropriate alternative refrigerants toR134a volumetric cooling capacity and discharge tem-perature Figure 13 illustrates the volumetric refrigerationcapacity (VCC) and the discharge temperature versus theevaporating temperature for all investigated refrigerantse volumetric refrigeration capacity expresses the coolingcapacity per unit volume at the exit of the evaporator Itindicates the volume of refrigerants handled by the com-pressor It was noted that R134a has the highest volumetriccooling capacity followed by R152a and R1234yf while theR1234ze(E) has lowest values of volumetric cooling ca-pacity is mean that the refrigerants R152a and R1234yfcan be replaced by R134a on the same compressor size inwhich the refrigerant R1234ze(E) needs to resize thecompressor for a given duty

It is necessary to study the discharge temperature for thelow-GWP refrigerant compared with R134a in order toclarify the steadiness and lifetime of the compressor

Referring to Figure 13 which illustrates the dischargetemperature versus the evaporating temperature for all in-vestigated refrigerants it was noted that the refrigerantR152a has the highest discharge temperature and it isimpediment in replacement between R152a and R134awhile the discharge temperature of R1234ze(E) and R1234yfis lower than that of R134a which is considered an advantagein replacement between R1234ze(E) R1234yf and R134a

e changing of the evaporating temperature affects theCOP of the system positively which is illustrated in Figure 14As the evaporating temperature increased the COP of therefrigeration system increased which can be attributed to theincrease in cooling capacity and was more rapid than theincrease in compressor powere refrigerant R1234ze(E) hasthe highest values of the COP among all the investigatedrefrigerants It was confirmed that the thermal performance ofthe R1234yf refrigerant (GWP100 358 times less than that ofR134a) was the closest to the thermal performance of theR134a system and therefore a more environmentally sus-tainable refrigerant for automotive air conditioning

e exergy destruction for the system compressor withdifferent evaporating temperatures is illustrated in Figure 15e highest exergy destruction through the compressor wasobtained for R1234ze(E) followed by R134a while R152a hasthe lowest values of exergy destruction Compared with thebase refrigerant of R134a the compressor exergy destructionof the refrigerant R1234ze(E) was higher by 65 while thecompressor exergy destruction of R1234yf and R152a wasreduced by 11 and 40 respectively e total exergy

0

02

04

06

08

1

12

E tot

al (k

W)

15 20 25 30 35 40 45 50Tc (degC)

Te = 10degCV = 00031m3s

R134aR152a

R1234yfR1234ze(E)

Figure 11 Total exergy destruction versus condensing temperature

005

01

015

02

025

03

035

04

15 20 25 30 35 40 45 50

E com

p (k

W)

Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degCV = 00031m3s

Figure 10 Exergy destruction in compressor versus condensingtemperature

8 Advances in Materials Science and Engineering

destruction of the all-cycle components for different types ofrefrigerants and the evaporating temperature is illustrated inFigure 16 e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the total exergydestruction of R1234yf and R152a was lower than that ofR134a by 15 and 45 respectively

623 4e Effect of Refrigerant Flow Rate e refrigerantvolume flow rate variation which was produced as a result ofvarying compressor speed which in turn was originated fromautomotive crankshaft speed affects the performance of theautomotive air conditioninge effect of varying volume flowrate on the cooling capacity and the coefficient of performanceis illustrated in Figures 17 and 18 for a typical condition ofTe 10degC and Tc 35degC e refrigerant mass flow rate variedas the RPM of the crankshaft was changed which depend on

Table 3 Results of the investigated refrigerants at different condensing temperatures

Item Tc oC R152a R1234yf R1234ze(E) R134a

Cooling capacity

30 660 669 561 69035 644 638 538 66540 624 606 515 63945 604 573 491 612

Compressor power

30 158 169 125 17135 1774 190 143 19440 1984 211 160 21545 2191 231 177 237

COP

30 418 396 447 40335 363 336 377 34440 315 288 322 29745 276 248 278 258

Total exergy destruction Etotal

30 0549 0851 0845 074835 0530 0812 0821 073040 0524 0780 0801 071045 0532 0770 0797 0701

Total exergy efficiency ηtotal

30 0322 028 0357 03435 0299 026 0336 03240 027 025 031 0345 0255 024 029 028

0

05

1

15

2

25

3

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Pow

er (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 12 Compressor power versus evaporating temperature

Disc

harg

e tem

pera

ture

(degC)

0

20

40

60

80

100

120

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Vol

umet

ric co

olin

g ca

paci

ty (k

Jm3 )

Te (degC)

VCC R134aVCC R152VCC R1234yfVCC R1234ze

Tdis R134aTdis R152aTdis R1234yfTdis R1234ze(E)

Figure 13 Effect of evaporating temperature on volumetriccooling capacity and discharge temperature

Advances in Materials Science and Engineering 9

the rate of fuel consumption of the automotive engine Inpractice the refrigerant mass flow rate ( _m ρ _v) which is therefrigerant density multiplied by volume flow rate affects thecooling capacity and compressor power according to equa-tions (1) and (2) in which the density varies according tovariation in evaporating temperature erefore the influenceof the refrigerant flow rate was evident to the coefficient ofperformance As the refrigerant flow rate increases the COPdecreases which can be explained by the increase in com-pressor power with a flow rate greater than the increase incooling capacity It is noted that the refrigerant R1234ze(E) hasthe highest COP between investigated refrigerants

e total exergy destruction of the compressor con-denser expansion valve and evaporator for the differentrefrigerant types is illustrated in Figure 19 e highestexergy destruction of the compressor was obtained forR1234ze(E) and the highest exergy destruction of thecondenser was obtained for R1234fy while the lowest valueof exergy destruction for the compressor and condenser wasobtained for R152a e highest values of the exergy de-struction for the evaporator and expansion valve were ob-tained for R1234ze(E) and R1234fy respectively

Exergy efficiency can give more logical ways to improvethe energy performance of automotive air conditioning Forthat reason the exergy analysis which was performed foreach cycle component should be considered integrated [6]Figures 20 and 21 show the total exergy efficiency with both

1

2

3

4

5

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

COP

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 14 COP versus evaporating temperature for Tc 35degC

005

01

015

02

025

03

035

04

ndash15 ndash10 ndash5 0 5 10 15 20

E com

p (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 15 Exergy destruction in compressor versus evaporatingtemperature

0

01

02

03

04

05

06

07

08

09

1

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

E tot

al

Figure 16 Total exergy destruction versus evaporatingtemperature

10 Advances in Materials Science and Engineering

0

1

2

3

4

5

6

7

8

0 05 1 15 2 25 3 35

Cool

ing

capa

city

(kW

)

V lowast 103 (m3s)

R134aR152a

R1234yfR1234ze(E)

Figure 17 Cooling capacity versus refrigerant flow rate at Tc 35degC

1

2

3

4

5

6

0 05 1 15 2 25 3 35

COP

R134aR152a

R1234yfR1234ze(E)

V lowast 103 (m3s)

Figure 18 COP versus refrigerant volume flow rate

Advances in Materials Science and Engineering 11

condensing and evaporating temperatures e total exergyefficiency was decreased with the condensing temperaturewhile it was increased with the evaporating temperature For

both condensing and evaporating temperatures the re-frigerant R1234yf has the lowest exergy efficiency followedby R152a e highest exergy efficiency was obtained withR1234ze(E) at different condensing temperatures while atdifferent evaporating temperatures the highest exergy effi-ciency was obtained for R134a From the environmentalthermal and exergy point of view the refrigerant R1234yfhas the best performance among all refrigerants that havebeen investigated to replace R134a in an automotive air-conditioning system

7 Conclusion

Energy and exergy analysis was presented for many envi-ronmentally friendly refrigerants as a drop-in replacementof current high-GWP of R134a in the automotive air-con-ditioning system ree alternative refrigerants which isdistinguished by zero ODP and GWP100lt 150 were inves-tigated with particular reference to the current R134a re-frigerant (GWP100 1430) e exergy destruction of eachcomponent and the exergy efficiency at different condensingtemperatures evaporating temperatures and refrigerantflow rates were presented and the main conclusions aresummarized as follows

(i) For all values of condensing and evaporatingtemperatures a higher system COP was obtained at

01

02

03

04

05

06

07

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degC V = 00031m3s

η tot

al

Figure 20 Total exergy efficiency versus condensing temperature

0

01

02

03

04

05

06

15 20 25 30 35 40 45 50Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degC V = 00031m3s

η tot

al

Figure 21 Total exergy efficiency versus evaporating temperature

R134a R152a R1234yf R1234ze

030

025

020

015

010

005

000

CompressorCondenser

ExpansionEvaporator

Figure 19 Total exergy destruction of each component for dif-ferent refrigerant types

12 Advances in Materials Science and Engineering

a lower compressor speed which was producedfrom slow crankshaft RPM

(ii) A reduction in the cooling capacity by 9 and inCOP by 27 was confirmed when a condensingtemperature increased by 5degC

(iii) Based on the test results the refrigerant R1234ze(E)had the highest coefficient of performance amongall investigated refrigerants

(iv) e refrigerant R1234yf was considered the closestin thermal performance to the refrigerant R134a

(v) e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the totalexergy destruction of R1234yf and R152a was lowerthan that of R134a by 15 and 45 respectively

(vi) e refrigerant R1234ze(E) was the most envi-ronmentally acceptable and had the best energeticand exergetic performance among all the testedrefrigerants

(vii) e highest exergy efficiency was obtained forR1234ze(E) at different condensing temperatureswhile at different evaporating temperatures thehighest exergy efficiency was obtained for R134a

Nomenclature

COP coefficient of performanceCP specific heat kJkgmiddotKEmiddot

x exergy kWh specific enthalpy kJkg_mref refrigerant flow rate kgsp refrigerant pressure kPaQ rate of heat transfer kWRPM revolution per minute minminus 1

s entropy kJkgmiddotKT temperature K_V refrigerant flow rate m3sVCC volumetric cooling capacity kJm3

W compressor power kWGWP100 global warming potential for 100 yearsΡ density kgm3

c coolingcomp compressorcond condenserexp expansionevap evaporatordest destructiondis dischargein inletis isentropicmech mechanicalo dead stateout outlet

Data Availability

e data that support the findings of this study are availableupon request from the corresponding author

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e authors would like to express their sincere gratitude tothe Public Authority for Applied Education and Training(PAAET) Kuwait for supporting and funding this workResearch Project No TS -16-12 Research Project TitleldquoEnergetic and exergetic analysis of R1234yf R1234ze andR152 as a low-GWP alternatives of R134a in automotive airconditioningrdquo Special appreciation to Refrigeration and AirConditioning Department Faculty of Industrial EducationHelwan University Egypt for the technical assistance ex-tended to the authors

References

[1] I P Koronaki D Cowan G Maidment et al ldquoRefrigerantemissions and leakage prevention across Europemdashresultsfrom the real skills Europe projectrdquo Energy vol 45 no 1pp 71ndash80 2012

[2] Environmental Protection Agency Protection of StratosphericOzone Change of Listing Status for Certain Substitutes underthe Significant New Alternatives Policy Program Rules andRegulations Environmental Protection Agency EPAWashington DC USA 2015

[3] I Dincer and A R Marc Exergy Energy Environment andSustainable Development Elsevier Amsterdam NetherlandsSecond edition 2016

[4] H Cho and C Park ldquoExperimental investigation of perfor-mance and exergy analysis of automotive air conditioningsystems using refrigerant R1234yf at various compressorspeedsrdquo Applied 4ermal Engineering vol 101 pp 30ndash372016

[5] B Jemaa R Mansouri I Boukholda and A Bellagi ldquoEnergyand exergy investigation of R1234ze(E) as R134a replacementin vapor compression chillersrdquo International Journal of Hy-drogen Energy vol 42 no 17 pp 12877ndash12887 2017

[6] K Zhang Y Zhu J Liu X Niu and X Yuan ldquoExergy andenergy analysis of a double evaporating temperature chillerrdquoEnergy and Buildings vol 165 pp 464ndash471 2018

[7] J K Verma A Satsangi and V Chaturani ldquoA review ofalternative to R134a (CH3CH2F) refrigerantrdquo InternationalJournal of Emerging Technology and Advanced Engineeringvol 3 no 1 pp 300ndash304 2013

[8] J Garcia T Ali W M Duarte A Khosravi and L MachadoldquoComparison of transient response of an evaporatormodel forwater refrigeration system working with R1234yf as a drop-inreplacement for R134ardquo International Journal of Refrigera-tion vol 91 pp 211ndash222 2018

[9] E Navarro I O Martınez-Galvan J Nohales andJ Gonzalvez-Macia ldquoComparative experimental study of anopen piston compressor working with R-1234yf R-134a andR-290rdquo International Journal of Refrigeration vol 36 no 3pp 768ndash775 2013

[10] J Navarro-Esbrı J M Mendoza-Miranda A Mota-BabiloniA Barraga-Cervera A Barragan-Cervera and J M Belman-Flores ldquoExperimental analysis of R1234yf as a drop-in re-placement for R134a in a vapor compression systemrdquo In-ternational Journal of Refrigeration vol 36 no 3pp 870ndash880 2013

Advances in Materials Science and Engineering 13

[11] A Gomaa ldquoPerformance characteristics of automotive airconditioning system with refrigerant R134a and its alterna-tivesrdquo International Journal of Energy and Power Engineeringvol 4 no 3 pp 168ndash177 2015

[12] Y Lee and D Jung ldquoA brief performance comparison ofR1234yf and R134a in a bench tester for automobile appli-cationsrdquo Applied 4ermal Engineering vol 35 pp 240ndash2422012

[13] J M Belman-Flores V H Rangel-Hernandez S Uson andC Rubio-Maya ldquoEnergy and exergy analysis of R1234yf asdrop-in replacement for R134a in a domestic refrigerationsystemrdquo Energy vol 132 pp 116ndash125 2017

[14] M Joybari M H Hatamipour A Rahimi and F ModarresldquoExergy analysis and optimization of R600a as a replacementof R134a in a domestic refrigerator systemrdquo InternationalJournal of Refrigeration vol 36 no 4 pp 1233ndash1242 2013

[15] D Sanchez R Cabello R Llopis I Arauzo J Catalan-Giland E Torrella ldquoEnergy performance evaluation of R1234yfR1234ze(E) R600a R290 and R152a as low-GWP R134aalternativesrdquo International Journal of Refrigeration vol 74pp 269ndash282 2017

[16] S V Shaik and T P Ashok Babu ldquoeoretical computation ofperformance of sustainable energy efficient R22 alternativesfor residential air conditionersrdquo Energy Procedia vol 138pp 710ndash716 2017

[17] Z Li H Jiang X Chen and K Liang ldquoComparative study onenergy efficiency of low GWP refrigerants in domestic re-frigerators with capacity modulationrdquo Energy and Buildingsvol 192 pp 93ndash100 2019

[18] S S Vali T P Setty and A Babu ldquoAnalytical computation ofthermodynamic performance parameters of actual vapourcompression refrigeration system with R22 R32 R134aR152a R290 and R1270rdquo MATEC Web of Conferencesvol 144 Article ID 04009 2018

[19] G Relue and S Kopchick New Refrigerants Designation andSafety Classifications E360 Forum Emerson Raleigh NCUSA 2017

[20] ASHRAE Standard 34Designation and Safety Classification ofRefrigerants American Society of Heating Ventilating andAir-Conditioning Engineers Atlanta GA USA 2010

[21] J P Holman Experimental Method for Engineerspp 62ndash65McGraw-Hill Book Company New York NY USA Eighthedition 2001

[22] B O Bolaji ldquoExperimental study of R152a and R32 to replaceR134a in a domestic refrigeratorrdquo Energy vol 35 no 9pp 3793ndash3798 2010

[23] M Fatouh A I Eid and N Nabil ldquoPerformance of water-to-water vapor compression refrigeration system using R22 al-ternatives part I system simulationrdquo Engineering ResearchJournal vol 124 pp M19ndashM43 2009

[24] A Yataganbaba A Kilicarslan and I Kurtbas ldquoExergyanalysis of R1234yf and R1234ze as R134a replacements in atwo evaporator vapour compression refrigeration systemrdquoInternational Journal of Refrigeration vol 60 pp 26ndash37 2015

[25] G F Nellis and S A Klein Engineering Equation Solver (EES)F-Chart Software Wiley Middleton WI USA 2013

[26] R Llopis E Torrella R Cabello and D Sanchez ldquoPerfor-mance evaluation of R404A and R507A refrigerant mixturesin an experimental double-stage vapour compression plantrdquoApplied Energy vol 87 no 5 pp 1546ndash1553 2010

14 Advances in Materials Science and Engineering

5 Exergy Analysis

Exergy analysis is a method for determining the availabilityof the energy that can be used in a certain system in whichthe deviation of the refrigeration cycle state from a givensituation to the reference situation Exergy analysis is aneffective tool to find out where and how much of the inputenergy of a system was lost e exergy balance was astatement of energy degradation (second law of thermo-dynamics) e following assumptions were considered inthe system exergy analysis

(i) e steady-state conditions were satisfied for allsystem components

(ii) e pressure losses in the pipelines were neglected(iii) e kinetic energy potential energy and exergy

losses were not considered(iv) e heat gain and heat loss from the system were

ignored

A graphical presentation of exergy balance through therefrigeration cycle of the automotive air-conditioning sys-tem is illustrated in Figure 4 e mathematical represen-tative of the exergy (second law analysis) can be expressed as

Emiddot

xdest 1113944Emiddot

xin minus 1113944Emiddot

xout + 1113944 Qmiddot

1 minusTo

T1113874 11138751113890 1113891

in

minus 1113944 Qmiddot

1 minusTo

T1113874 11138751113890 1113891

out+ 1113944 W

middot

in minus 1113944 Wmiddot

out

(8)

e exergy efficiency ηEx is a very useful measure of theextent to which the cycle approaches an ideal behavior eexergy efficiency is the ratio of the actual COP to the max-imum possible COP at the same operating condition [24]

Table 2 Uncertainties of themeasuring instruments and calculatedparameters

Item Uncertainty ()ermocouples (type-k) plusmn21Hotwire anemometer plusmn33Refrigerant flowmeter plusmn29Refrigerant pressure gauge plusmn3Refrigeration capacity plusmn63Compressor power plusmn72COP plusmn56Heat rejection plusmn73Total energy destruction plusmn79

p

3

4

Expansiondevice

Condenser

CompressorEvaporator

h

22is

1

Figure 3 Pressure-enthalpy diagram of the air-conditioning re-frigeration cycle

Thermocouples

Condenser Heater

Filter drier

Liquid receiver

Flowmeter

Expansionvalve

EvaporatorHeater

Voltagecontroller

Voltagecontroller

GPIS

Computer

Fan controller

Fan controller

P

P

T

T

P T

Compressor Electric motor

Variablespeed drive

Figure 2 Schematic diagram of the experimental test rig

4 Advances in Materials Science and Engineering

ηEx Emiddot

xoutEmiddot

xin 1 minus

Emiddot

xdestEmiddot

xin (9)

When the thermodynamic process is reversible the exergyefficiency ηEx 1 and the exergy efficiency lt 1 in other casesermodynamically the exergy in any state was given by

Emiddot

x h minus ho( 1113857 minus To s minus so( 1113857 (10)

e above equations were applied to each thermody-namic process of the refrigeration cycle in which the exergydestruction and efficiency can be expressed as follows

Compressor

Emiddot

xdest Comp Wmiddot

comp + Emiddot

x1 minus Emiddot

x2

ηExComp 1 minusEmiddot

xdest Comp

Wmiddot

in

⎛⎝ ⎞⎠

(11)

Condenser

Emiddot

xdest Cond Emiddot

x2 minus Emiddot

x3

ηExCond 1 minusEmiddot

xdest CondEmiddot

x2 minus Emiddot

x3⎛⎝ ⎞⎠

(12)

Expansion valve

Emiddot

xdest Exp Emiddot

x3 minus Emiddot

x4

ηEx Exp 1 minusEmiddot

x3Emiddot

x4⎛⎝ ⎞⎠

(13)

Evaporator

Emiddot

xdest Evap Emiddot

x4 minus Emiddot

x11113874 1113875 + mmiddot

h1 minus h4( 1113857 1 minusTo

T11113888 11138891113890 1113891

ηExEvap Emiddot

xdest EvapEmiddot

x1 minus Emiddot

x4

(14)

e total energy destruction for all refrigeration cyclecomponents can be expressed as

Emiddot

xdesttotal Emiddot

xdestComp + Emiddot

xdestCond + Emiddot

xdestExp + Emiddot

xdestEvap

(15)

e Engineering Equation Solver [25] software was usedwith the previous equations to develop a solution model ofeach investigated refrigerant with different input parametersat all state points of temperatures and refrigerant mass flowrate corresponding to and similar to that of experiments

6 Results and Discussion

e results of the low-GWP refrigerants in the automotiveair-conditioning system with R134a as baseline were pre-sented as an energetic performance involving cooling ca-pacity compressor power and coefficient of performancefor different compressor speeds and evaporating and con-densing temperatures e exergetic performance is pre-sented in the form of exergy destruction of each cyclecomponent total exergy destruction and exergy efficiency atdifferent cases of refrigerant flow rate and evaporating andcondensing temperatures

61 4e Effect of Varying Compressor RPM e air condi-tioning in the automotive application and in most cases thecompressor is semihermetic which is usually connected tothe engine crankshaft by a belt via two pulleys in which thecompressor RPM varies according to crankshaft RPMwhich in turn affects the refrigerant flow rate e effect ofvarying compressor rotation of R134a on the compressorpower at various condensing temperatures is shown inFigure 5 e compressor power consumption decreaseswith a lower value of the compressor speed and con-densing temperature e ambient air temperature affectsthe compressor power directly As the condensing tem-perature increased by 5degC the compressor power increasedby 13 in which there was an increase in compressorpower by 17 when the RPM of the compressor speedaccelerated by 15 Figure 6 illustrates experimentallyboth the cooling capacity and COP of R134a with thecompressor RPM at various condensing temperatures ecooling capacity increases with the increase of compressorRPM due to the increase in refrigerant mass flow rate Anincrease in the condensing temperature by 5degC led to areduction in the cooling capacity and the COP by 9 and27 respectively e decrease in compressor RPM led toincrease in COP of the refrigeration cycle which can berevealed to the decrease in compressor RPM which yieldedless friction between moving parts and consequently ahigher isentropic efficiency of the compression process wasobtained

e investigation of a wide range of operating conditionson the automotive air-conditioning system with differentrefrigerant types of GWP100lt 150 was studied using Engi-neering Equation Solver software (EES 2017) A validationbetween the experimental and theoretical (EES) results wasperformed at the same operating condition which was in fairagreement erefore the characteristics of the refrigerants

External exergylosses

Internal exergylosses Produced

utilizable exergy

Output exergy

Transiting exergy

Util

izab

le ex

ergy

Con

sum

ed ex

ergy

Inpu

t exe

rgy

Figure 4 Graphical presentation of exergy balance [24]

Advances in Materials Science and Engineering 5

R152a R1234yf and R1234ze(E) were investigated incomparison with a current high-GWP refrigerant of R134a

62 Performance Criteria of Investigated Refrigerants eperformance criteria of the low GWP refrigerants of R152aR1234yf and R1234ze(E) compared with R134a werespecified to the effect of evaporating temperature con-densing temperature and refrigerant flow rate on the en-ergetic and exegetic parameters of the automotive airconditioning system In particular the most possible drop-inreplacement refrigerant to R134a in automotive air condi-tioning application was R152a (GWP100 less 10 times)R1234yf (GWP100 less 358 times) and R1234ze(E) (GWP100less 238 times)

621 4e Effect of Condensing Temperature In particularthe variation of the condensing temperature through the daymonth and season affects the system performance thereforea wide range of condensing temperature 20degCleTcle 45degC wasconsidered Figure 7 illustrates the cooling capacity of dif-ferent refrigerant types at Te 10degC and _V 00031m3s Atthe same operating condition it was noted that a reduction incooling capacity was recorded for R152a R1234yf andR1234ze(E) compared with R134a by 36 38 and 19respectively e compressor power was impacted by

changing of condensing temperature for different refrigeranttypes which is illustrated in Figure 8 At the same operatingcondition the compressor power consumption of R134a washigher than that of R152a R1234yf and R1234ze(E) by 8516 and 28 respectively It has been shown that the re-frigerant R134a has higher values of both refrigeration ca-pacity and compressor power than the proposed refrigerantsat the same operating condition In this case the coefficient ofperformance (COP) is themost important factor to determinethe performance characteristics of the proposed refrigerantswhich is illustrated in Figure 9 e COP of R134a was lowerthan that of R1234ze(E) and R152a by 108 and 56 re-spectively It was confirmed that the COP of the refrigerantR1234yf wasvery close to the performance of R134a in whichthe COP of R134a was higher by 2

e exergy destruction of the system compressor withdifferent condensing temperatures is shown in Figure 10e highest exergy destruction through the compressor wasobtained for R1234yf followed by R134a while R152a has thelowest values of exergy destruction Compared with the baserefrigerant of R134a the compressor exergy destruction ofthe refrigerant R1234ze(E) was higher by 6 while a re-duction in the compressor exergy destruction was obtainedby 14 and 29 for the refrigerants R1234yf and R152arespectively compared with R134a e exergy destructionof the evaporator expansion valve and condenser was alsocalculated to form the total exergy destructione variationof the total exergy destruction of all refrigeration cyclecomponents with the condensing temperature is illustrated

0

1

2

3

4

5

6

7

8

0

1

2

3

4

5

6

7

8

9

10

0 500 1000 1500 2000RPM

Qevap Tc = 25degCQevap Tc = 35degCQevap Tc = 45degC

COP Tc = 25degCCOP Tc = 35degCCOP Tc = 45degC

COP

Qev

a (kW

)

Figure 6 Cooling capacity and COP versus RPM of R134a (ex-perimental results)

0 300 600 900 1200 1500 1800RPM

3

25

2

15

1

05

0

Pow

er (k

W)

Tc = 25degCTc = 30degCTc = 35degC

Tc = 40degCTc = 45degC

Figure 5 Compressor power versus RPM of R134a (experimentalresults)

6 Advances in Materials Science and Engineering

in Figure 11 e total exergy destruction of R1234yf andR1234ze(E) was quite similar in which the total exergydestruction of both refrigerants were higher than that ofR134a by 12 while the total exergy destruction of R152awas lower than that of R134a by 26

e effect of varying condensing temperature on theenergy and exergy parameters is summarized as a sample ofresults in Table 3

622 4e Effect of Evaporating Temperature e evapo-rating temperature was different from one application toanother and it should be noted that the evaporating tem-perature affects the system performance positively A widerange of evaporating temperatures which were applied inmany air conditioning applications (minus 15degC to 15degC) wastested for different refrigerant types of R134a R152aR124yf and R1234ze(E) e compressor power con-sumption was influenced by varying evaporating tempera-ture for all investigated refrigerants as illustrated inFigure 12 Although the enthalpy difference (h2 minus h1) inEquation (4) decreases as the evaporating temperature in-creases the values of the compressor power increase as theevaporating temperature increases is can be explained onthe basis of equations (2) and (4) where the enthalpy dif-ference (h2 minus h1) decreases with the increase in the evapo-rating temperature while the volumetric efficiency increasesand the specific volume decreases in accordance with

0

05

1

15

2

25

3

15 20 25 30 35 40 45 50

Pow

er (k

W)

Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 8 Effect of condensing temperature on compressor powerfor investigated refrigerants

1

2

3

4

5

6

7

8

15 20 25 30 35 40 45 50

COP

Tc (degC)

Te = 10degCV = 00031m3s

R134aR152a

R1234yfR1234ze(E)

Figure 9 Effect of condensing temperature on COP for investi-gated refrigerants

2

3

4

5

6

7

8

9

10

15 20 25 30 35 40 45 50

R134aR152a

R1234yfR1234ze(E)

Coo

ling

capa

city

(kW

)

Tc (degC)

Figure 7 Effect of condensing temperature on cooling capacity forinvestigated refrigerants

Advances in Materials Science and Engineering 7

Equation (2) is led to an increase in mass flow rate beinggreater than the decrease in the enthalpy difference (h2 minus h1)and consequently the compressor power consumption in-creases with evaporating temperature is trend curveconfirmed with Li et al [17] and Llopis et al [26]

e compressor power of R134a and R1234yf was quitesimilar A reduction in a compressor power for R152a andR1234ze(E) by 8 and 26 respectively was occurred whencompared with R134a

ere are two important parameters that can charac-terize the most appropriate alternative refrigerants toR134a volumetric cooling capacity and discharge tem-perature Figure 13 illustrates the volumetric refrigerationcapacity (VCC) and the discharge temperature versus theevaporating temperature for all investigated refrigerantse volumetric refrigeration capacity expresses the coolingcapacity per unit volume at the exit of the evaporator Itindicates the volume of refrigerants handled by the com-pressor It was noted that R134a has the highest volumetriccooling capacity followed by R152a and R1234yf while theR1234ze(E) has lowest values of volumetric cooling ca-pacity is mean that the refrigerants R152a and R1234yfcan be replaced by R134a on the same compressor size inwhich the refrigerant R1234ze(E) needs to resize thecompressor for a given duty

It is necessary to study the discharge temperature for thelow-GWP refrigerant compared with R134a in order toclarify the steadiness and lifetime of the compressor

Referring to Figure 13 which illustrates the dischargetemperature versus the evaporating temperature for all in-vestigated refrigerants it was noted that the refrigerantR152a has the highest discharge temperature and it isimpediment in replacement between R152a and R134awhile the discharge temperature of R1234ze(E) and R1234yfis lower than that of R134a which is considered an advantagein replacement between R1234ze(E) R1234yf and R134a

e changing of the evaporating temperature affects theCOP of the system positively which is illustrated in Figure 14As the evaporating temperature increased the COP of therefrigeration system increased which can be attributed to theincrease in cooling capacity and was more rapid than theincrease in compressor powere refrigerant R1234ze(E) hasthe highest values of the COP among all the investigatedrefrigerants It was confirmed that the thermal performance ofthe R1234yf refrigerant (GWP100 358 times less than that ofR134a) was the closest to the thermal performance of theR134a system and therefore a more environmentally sus-tainable refrigerant for automotive air conditioning

e exergy destruction for the system compressor withdifferent evaporating temperatures is illustrated in Figure 15e highest exergy destruction through the compressor wasobtained for R1234ze(E) followed by R134a while R152a hasthe lowest values of exergy destruction Compared with thebase refrigerant of R134a the compressor exergy destructionof the refrigerant R1234ze(E) was higher by 65 while thecompressor exergy destruction of R1234yf and R152a wasreduced by 11 and 40 respectively e total exergy

0

02

04

06

08

1

12

E tot

al (k

W)

15 20 25 30 35 40 45 50Tc (degC)

Te = 10degCV = 00031m3s

R134aR152a

R1234yfR1234ze(E)

Figure 11 Total exergy destruction versus condensing temperature

005

01

015

02

025

03

035

04

15 20 25 30 35 40 45 50

E com

p (k

W)

Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degCV = 00031m3s

Figure 10 Exergy destruction in compressor versus condensingtemperature

8 Advances in Materials Science and Engineering

destruction of the all-cycle components for different types ofrefrigerants and the evaporating temperature is illustrated inFigure 16 e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the total exergydestruction of R1234yf and R152a was lower than that ofR134a by 15 and 45 respectively

623 4e Effect of Refrigerant Flow Rate e refrigerantvolume flow rate variation which was produced as a result ofvarying compressor speed which in turn was originated fromautomotive crankshaft speed affects the performance of theautomotive air conditioninge effect of varying volume flowrate on the cooling capacity and the coefficient of performanceis illustrated in Figures 17 and 18 for a typical condition ofTe 10degC and Tc 35degC e refrigerant mass flow rate variedas the RPM of the crankshaft was changed which depend on

Table 3 Results of the investigated refrigerants at different condensing temperatures

Item Tc oC R152a R1234yf R1234ze(E) R134a

Cooling capacity

30 660 669 561 69035 644 638 538 66540 624 606 515 63945 604 573 491 612

Compressor power

30 158 169 125 17135 1774 190 143 19440 1984 211 160 21545 2191 231 177 237

COP

30 418 396 447 40335 363 336 377 34440 315 288 322 29745 276 248 278 258

Total exergy destruction Etotal

30 0549 0851 0845 074835 0530 0812 0821 073040 0524 0780 0801 071045 0532 0770 0797 0701

Total exergy efficiency ηtotal

30 0322 028 0357 03435 0299 026 0336 03240 027 025 031 0345 0255 024 029 028

0

05

1

15

2

25

3

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Pow

er (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 12 Compressor power versus evaporating temperature

Disc

harg

e tem

pera

ture

(degC)

0

20

40

60

80

100

120

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Vol

umet

ric co

olin

g ca

paci

ty (k

Jm3 )

Te (degC)

VCC R134aVCC R152VCC R1234yfVCC R1234ze

Tdis R134aTdis R152aTdis R1234yfTdis R1234ze(E)

Figure 13 Effect of evaporating temperature on volumetriccooling capacity and discharge temperature

Advances in Materials Science and Engineering 9

the rate of fuel consumption of the automotive engine Inpractice the refrigerant mass flow rate ( _m ρ _v) which is therefrigerant density multiplied by volume flow rate affects thecooling capacity and compressor power according to equa-tions (1) and (2) in which the density varies according tovariation in evaporating temperature erefore the influenceof the refrigerant flow rate was evident to the coefficient ofperformance As the refrigerant flow rate increases the COPdecreases which can be explained by the increase in com-pressor power with a flow rate greater than the increase incooling capacity It is noted that the refrigerant R1234ze(E) hasthe highest COP between investigated refrigerants

e total exergy destruction of the compressor con-denser expansion valve and evaporator for the differentrefrigerant types is illustrated in Figure 19 e highestexergy destruction of the compressor was obtained forR1234ze(E) and the highest exergy destruction of thecondenser was obtained for R1234fy while the lowest valueof exergy destruction for the compressor and condenser wasobtained for R152a e highest values of the exergy de-struction for the evaporator and expansion valve were ob-tained for R1234ze(E) and R1234fy respectively

Exergy efficiency can give more logical ways to improvethe energy performance of automotive air conditioning Forthat reason the exergy analysis which was performed foreach cycle component should be considered integrated [6]Figures 20 and 21 show the total exergy efficiency with both

1

2

3

4

5

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

COP

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 14 COP versus evaporating temperature for Tc 35degC

005

01

015

02

025

03

035

04

ndash15 ndash10 ndash5 0 5 10 15 20

E com

p (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 15 Exergy destruction in compressor versus evaporatingtemperature

0

01

02

03

04

05

06

07

08

09

1

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

E tot

al

Figure 16 Total exergy destruction versus evaporatingtemperature

10 Advances in Materials Science and Engineering

0

1

2

3

4

5

6

7

8

0 05 1 15 2 25 3 35

Cool

ing

capa

city

(kW

)

V lowast 103 (m3s)

R134aR152a

R1234yfR1234ze(E)

Figure 17 Cooling capacity versus refrigerant flow rate at Tc 35degC

1

2

3

4

5

6

0 05 1 15 2 25 3 35

COP

R134aR152a

R1234yfR1234ze(E)

V lowast 103 (m3s)

Figure 18 COP versus refrigerant volume flow rate

Advances in Materials Science and Engineering 11

condensing and evaporating temperatures e total exergyefficiency was decreased with the condensing temperaturewhile it was increased with the evaporating temperature For

both condensing and evaporating temperatures the re-frigerant R1234yf has the lowest exergy efficiency followedby R152a e highest exergy efficiency was obtained withR1234ze(E) at different condensing temperatures while atdifferent evaporating temperatures the highest exergy effi-ciency was obtained for R134a From the environmentalthermal and exergy point of view the refrigerant R1234yfhas the best performance among all refrigerants that havebeen investigated to replace R134a in an automotive air-conditioning system

7 Conclusion

Energy and exergy analysis was presented for many envi-ronmentally friendly refrigerants as a drop-in replacementof current high-GWP of R134a in the automotive air-con-ditioning system ree alternative refrigerants which isdistinguished by zero ODP and GWP100lt 150 were inves-tigated with particular reference to the current R134a re-frigerant (GWP100 1430) e exergy destruction of eachcomponent and the exergy efficiency at different condensingtemperatures evaporating temperatures and refrigerantflow rates were presented and the main conclusions aresummarized as follows

(i) For all values of condensing and evaporatingtemperatures a higher system COP was obtained at

01

02

03

04

05

06

07

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degC V = 00031m3s

η tot

al

Figure 20 Total exergy efficiency versus condensing temperature

0

01

02

03

04

05

06

15 20 25 30 35 40 45 50Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degC V = 00031m3s

η tot

al

Figure 21 Total exergy efficiency versus evaporating temperature

R134a R152a R1234yf R1234ze

030

025

020

015

010

005

000

CompressorCondenser

ExpansionEvaporator

Figure 19 Total exergy destruction of each component for dif-ferent refrigerant types

12 Advances in Materials Science and Engineering

a lower compressor speed which was producedfrom slow crankshaft RPM

(ii) A reduction in the cooling capacity by 9 and inCOP by 27 was confirmed when a condensingtemperature increased by 5degC

(iii) Based on the test results the refrigerant R1234ze(E)had the highest coefficient of performance amongall investigated refrigerants

(iv) e refrigerant R1234yf was considered the closestin thermal performance to the refrigerant R134a

(v) e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the totalexergy destruction of R1234yf and R152a was lowerthan that of R134a by 15 and 45 respectively

(vi) e refrigerant R1234ze(E) was the most envi-ronmentally acceptable and had the best energeticand exergetic performance among all the testedrefrigerants

(vii) e highest exergy efficiency was obtained forR1234ze(E) at different condensing temperatureswhile at different evaporating temperatures thehighest exergy efficiency was obtained for R134a

Nomenclature

COP coefficient of performanceCP specific heat kJkgmiddotKEmiddot

x exergy kWh specific enthalpy kJkg_mref refrigerant flow rate kgsp refrigerant pressure kPaQ rate of heat transfer kWRPM revolution per minute minminus 1

s entropy kJkgmiddotKT temperature K_V refrigerant flow rate m3sVCC volumetric cooling capacity kJm3

W compressor power kWGWP100 global warming potential for 100 yearsΡ density kgm3

c coolingcomp compressorcond condenserexp expansionevap evaporatordest destructiondis dischargein inletis isentropicmech mechanicalo dead stateout outlet

Data Availability

e data that support the findings of this study are availableupon request from the corresponding author

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e authors would like to express their sincere gratitude tothe Public Authority for Applied Education and Training(PAAET) Kuwait for supporting and funding this workResearch Project No TS -16-12 Research Project TitleldquoEnergetic and exergetic analysis of R1234yf R1234ze andR152 as a low-GWP alternatives of R134a in automotive airconditioningrdquo Special appreciation to Refrigeration and AirConditioning Department Faculty of Industrial EducationHelwan University Egypt for the technical assistance ex-tended to the authors

References

[1] I P Koronaki D Cowan G Maidment et al ldquoRefrigerantemissions and leakage prevention across Europemdashresultsfrom the real skills Europe projectrdquo Energy vol 45 no 1pp 71ndash80 2012

[2] Environmental Protection Agency Protection of StratosphericOzone Change of Listing Status for Certain Substitutes underthe Significant New Alternatives Policy Program Rules andRegulations Environmental Protection Agency EPAWashington DC USA 2015

[3] I Dincer and A R Marc Exergy Energy Environment andSustainable Development Elsevier Amsterdam NetherlandsSecond edition 2016

[4] H Cho and C Park ldquoExperimental investigation of perfor-mance and exergy analysis of automotive air conditioningsystems using refrigerant R1234yf at various compressorspeedsrdquo Applied 4ermal Engineering vol 101 pp 30ndash372016

[5] B Jemaa R Mansouri I Boukholda and A Bellagi ldquoEnergyand exergy investigation of R1234ze(E) as R134a replacementin vapor compression chillersrdquo International Journal of Hy-drogen Energy vol 42 no 17 pp 12877ndash12887 2017

[6] K Zhang Y Zhu J Liu X Niu and X Yuan ldquoExergy andenergy analysis of a double evaporating temperature chillerrdquoEnergy and Buildings vol 165 pp 464ndash471 2018

[7] J K Verma A Satsangi and V Chaturani ldquoA review ofalternative to R134a (CH3CH2F) refrigerantrdquo InternationalJournal of Emerging Technology and Advanced Engineeringvol 3 no 1 pp 300ndash304 2013

[8] J Garcia T Ali W M Duarte A Khosravi and L MachadoldquoComparison of transient response of an evaporatormodel forwater refrigeration system working with R1234yf as a drop-inreplacement for R134ardquo International Journal of Refrigera-tion vol 91 pp 211ndash222 2018

[9] E Navarro I O Martınez-Galvan J Nohales andJ Gonzalvez-Macia ldquoComparative experimental study of anopen piston compressor working with R-1234yf R-134a andR-290rdquo International Journal of Refrigeration vol 36 no 3pp 768ndash775 2013

[10] J Navarro-Esbrı J M Mendoza-Miranda A Mota-BabiloniA Barraga-Cervera A Barragan-Cervera and J M Belman-Flores ldquoExperimental analysis of R1234yf as a drop-in re-placement for R134a in a vapor compression systemrdquo In-ternational Journal of Refrigeration vol 36 no 3pp 870ndash880 2013

Advances in Materials Science and Engineering 13

[11] A Gomaa ldquoPerformance characteristics of automotive airconditioning system with refrigerant R134a and its alterna-tivesrdquo International Journal of Energy and Power Engineeringvol 4 no 3 pp 168ndash177 2015

[12] Y Lee and D Jung ldquoA brief performance comparison ofR1234yf and R134a in a bench tester for automobile appli-cationsrdquo Applied 4ermal Engineering vol 35 pp 240ndash2422012

[13] J M Belman-Flores V H Rangel-Hernandez S Uson andC Rubio-Maya ldquoEnergy and exergy analysis of R1234yf asdrop-in replacement for R134a in a domestic refrigerationsystemrdquo Energy vol 132 pp 116ndash125 2017

[14] M Joybari M H Hatamipour A Rahimi and F ModarresldquoExergy analysis and optimization of R600a as a replacementof R134a in a domestic refrigerator systemrdquo InternationalJournal of Refrigeration vol 36 no 4 pp 1233ndash1242 2013

[15] D Sanchez R Cabello R Llopis I Arauzo J Catalan-Giland E Torrella ldquoEnergy performance evaluation of R1234yfR1234ze(E) R600a R290 and R152a as low-GWP R134aalternativesrdquo International Journal of Refrigeration vol 74pp 269ndash282 2017

[16] S V Shaik and T P Ashok Babu ldquoeoretical computation ofperformance of sustainable energy efficient R22 alternativesfor residential air conditionersrdquo Energy Procedia vol 138pp 710ndash716 2017

[17] Z Li H Jiang X Chen and K Liang ldquoComparative study onenergy efficiency of low GWP refrigerants in domestic re-frigerators with capacity modulationrdquo Energy and Buildingsvol 192 pp 93ndash100 2019

[18] S S Vali T P Setty and A Babu ldquoAnalytical computation ofthermodynamic performance parameters of actual vapourcompression refrigeration system with R22 R32 R134aR152a R290 and R1270rdquo MATEC Web of Conferencesvol 144 Article ID 04009 2018

[19] G Relue and S Kopchick New Refrigerants Designation andSafety Classifications E360 Forum Emerson Raleigh NCUSA 2017

[20] ASHRAE Standard 34Designation and Safety Classification ofRefrigerants American Society of Heating Ventilating andAir-Conditioning Engineers Atlanta GA USA 2010

[21] J P Holman Experimental Method for Engineerspp 62ndash65McGraw-Hill Book Company New York NY USA Eighthedition 2001

[22] B O Bolaji ldquoExperimental study of R152a and R32 to replaceR134a in a domestic refrigeratorrdquo Energy vol 35 no 9pp 3793ndash3798 2010

[23] M Fatouh A I Eid and N Nabil ldquoPerformance of water-to-water vapor compression refrigeration system using R22 al-ternatives part I system simulationrdquo Engineering ResearchJournal vol 124 pp M19ndashM43 2009

[24] A Yataganbaba A Kilicarslan and I Kurtbas ldquoExergyanalysis of R1234yf and R1234ze as R134a replacements in atwo evaporator vapour compression refrigeration systemrdquoInternational Journal of Refrigeration vol 60 pp 26ndash37 2015

[25] G F Nellis and S A Klein Engineering Equation Solver (EES)F-Chart Software Wiley Middleton WI USA 2013

[26] R Llopis E Torrella R Cabello and D Sanchez ldquoPerfor-mance evaluation of R404A and R507A refrigerant mixturesin an experimental double-stage vapour compression plantrdquoApplied Energy vol 87 no 5 pp 1546ndash1553 2010

14 Advances in Materials Science and Engineering

ηEx Emiddot

xoutEmiddot

xin 1 minus

Emiddot

xdestEmiddot

xin (9)

When the thermodynamic process is reversible the exergyefficiency ηEx 1 and the exergy efficiency lt 1 in other casesermodynamically the exergy in any state was given by

Emiddot

x h minus ho( 1113857 minus To s minus so( 1113857 (10)

e above equations were applied to each thermody-namic process of the refrigeration cycle in which the exergydestruction and efficiency can be expressed as follows

Compressor

Emiddot

xdest Comp Wmiddot

comp + Emiddot

x1 minus Emiddot

x2

ηExComp 1 minusEmiddot

xdest Comp

Wmiddot

in

⎛⎝ ⎞⎠

(11)

Condenser

Emiddot

xdest Cond Emiddot

x2 minus Emiddot

x3

ηExCond 1 minusEmiddot

xdest CondEmiddot

x2 minus Emiddot

x3⎛⎝ ⎞⎠

(12)

Expansion valve

Emiddot

xdest Exp Emiddot

x3 minus Emiddot

x4

ηEx Exp 1 minusEmiddot

x3Emiddot

x4⎛⎝ ⎞⎠

(13)

Evaporator

Emiddot

xdest Evap Emiddot

x4 minus Emiddot

x11113874 1113875 + mmiddot

h1 minus h4( 1113857 1 minusTo

T11113888 11138891113890 1113891

ηExEvap Emiddot

xdest EvapEmiddot

x1 minus Emiddot

x4

(14)

e total energy destruction for all refrigeration cyclecomponents can be expressed as

Emiddot

xdesttotal Emiddot

xdestComp + Emiddot

xdestCond + Emiddot

xdestExp + Emiddot

xdestEvap

(15)

e Engineering Equation Solver [25] software was usedwith the previous equations to develop a solution model ofeach investigated refrigerant with different input parametersat all state points of temperatures and refrigerant mass flowrate corresponding to and similar to that of experiments

6 Results and Discussion

e results of the low-GWP refrigerants in the automotiveair-conditioning system with R134a as baseline were pre-sented as an energetic performance involving cooling ca-pacity compressor power and coefficient of performancefor different compressor speeds and evaporating and con-densing temperatures e exergetic performance is pre-sented in the form of exergy destruction of each cyclecomponent total exergy destruction and exergy efficiency atdifferent cases of refrigerant flow rate and evaporating andcondensing temperatures

61 4e Effect of Varying Compressor RPM e air condi-tioning in the automotive application and in most cases thecompressor is semihermetic which is usually connected tothe engine crankshaft by a belt via two pulleys in which thecompressor RPM varies according to crankshaft RPMwhich in turn affects the refrigerant flow rate e effect ofvarying compressor rotation of R134a on the compressorpower at various condensing temperatures is shown inFigure 5 e compressor power consumption decreaseswith a lower value of the compressor speed and con-densing temperature e ambient air temperature affectsthe compressor power directly As the condensing tem-perature increased by 5degC the compressor power increasedby 13 in which there was an increase in compressorpower by 17 when the RPM of the compressor speedaccelerated by 15 Figure 6 illustrates experimentallyboth the cooling capacity and COP of R134a with thecompressor RPM at various condensing temperatures ecooling capacity increases with the increase of compressorRPM due to the increase in refrigerant mass flow rate Anincrease in the condensing temperature by 5degC led to areduction in the cooling capacity and the COP by 9 and27 respectively e decrease in compressor RPM led toincrease in COP of the refrigeration cycle which can berevealed to the decrease in compressor RPM which yieldedless friction between moving parts and consequently ahigher isentropic efficiency of the compression process wasobtained

e investigation of a wide range of operating conditionson the automotive air-conditioning system with differentrefrigerant types of GWP100lt 150 was studied using Engi-neering Equation Solver software (EES 2017) A validationbetween the experimental and theoretical (EES) results wasperformed at the same operating condition which was in fairagreement erefore the characteristics of the refrigerants

External exergylosses

Internal exergylosses Produced

utilizable exergy

Output exergy

Transiting exergy

Util

izab

le ex

ergy

Con

sum

ed ex

ergy

Inpu

t exe

rgy

Figure 4 Graphical presentation of exergy balance [24]

Advances in Materials Science and Engineering 5

R152a R1234yf and R1234ze(E) were investigated incomparison with a current high-GWP refrigerant of R134a

62 Performance Criteria of Investigated Refrigerants eperformance criteria of the low GWP refrigerants of R152aR1234yf and R1234ze(E) compared with R134a werespecified to the effect of evaporating temperature con-densing temperature and refrigerant flow rate on the en-ergetic and exegetic parameters of the automotive airconditioning system In particular the most possible drop-inreplacement refrigerant to R134a in automotive air condi-tioning application was R152a (GWP100 less 10 times)R1234yf (GWP100 less 358 times) and R1234ze(E) (GWP100less 238 times)

621 4e Effect of Condensing Temperature In particularthe variation of the condensing temperature through the daymonth and season affects the system performance thereforea wide range of condensing temperature 20degCleTcle 45degC wasconsidered Figure 7 illustrates the cooling capacity of dif-ferent refrigerant types at Te 10degC and _V 00031m3s Atthe same operating condition it was noted that a reduction incooling capacity was recorded for R152a R1234yf andR1234ze(E) compared with R134a by 36 38 and 19respectively e compressor power was impacted by

changing of condensing temperature for different refrigeranttypes which is illustrated in Figure 8 At the same operatingcondition the compressor power consumption of R134a washigher than that of R152a R1234yf and R1234ze(E) by 8516 and 28 respectively It has been shown that the re-frigerant R134a has higher values of both refrigeration ca-pacity and compressor power than the proposed refrigerantsat the same operating condition In this case the coefficient ofperformance (COP) is themost important factor to determinethe performance characteristics of the proposed refrigerantswhich is illustrated in Figure 9 e COP of R134a was lowerthan that of R1234ze(E) and R152a by 108 and 56 re-spectively It was confirmed that the COP of the refrigerantR1234yf wasvery close to the performance of R134a in whichthe COP of R134a was higher by 2

e exergy destruction of the system compressor withdifferent condensing temperatures is shown in Figure 10e highest exergy destruction through the compressor wasobtained for R1234yf followed by R134a while R152a has thelowest values of exergy destruction Compared with the baserefrigerant of R134a the compressor exergy destruction ofthe refrigerant R1234ze(E) was higher by 6 while a re-duction in the compressor exergy destruction was obtainedby 14 and 29 for the refrigerants R1234yf and R152arespectively compared with R134a e exergy destructionof the evaporator expansion valve and condenser was alsocalculated to form the total exergy destructione variationof the total exergy destruction of all refrigeration cyclecomponents with the condensing temperature is illustrated

0

1

2

3

4

5

6

7

8

0

1

2

3

4

5

6

7

8

9

10

0 500 1000 1500 2000RPM

Qevap Tc = 25degCQevap Tc = 35degCQevap Tc = 45degC

COP Tc = 25degCCOP Tc = 35degCCOP Tc = 45degC

COP

Qev

a (kW

)

Figure 6 Cooling capacity and COP versus RPM of R134a (ex-perimental results)

0 300 600 900 1200 1500 1800RPM

3

25

2

15

1

05

0

Pow

er (k

W)

Tc = 25degCTc = 30degCTc = 35degC

Tc = 40degCTc = 45degC

Figure 5 Compressor power versus RPM of R134a (experimentalresults)

6 Advances in Materials Science and Engineering

in Figure 11 e total exergy destruction of R1234yf andR1234ze(E) was quite similar in which the total exergydestruction of both refrigerants were higher than that ofR134a by 12 while the total exergy destruction of R152awas lower than that of R134a by 26

e effect of varying condensing temperature on theenergy and exergy parameters is summarized as a sample ofresults in Table 3

622 4e Effect of Evaporating Temperature e evapo-rating temperature was different from one application toanother and it should be noted that the evaporating tem-perature affects the system performance positively A widerange of evaporating temperatures which were applied inmany air conditioning applications (minus 15degC to 15degC) wastested for different refrigerant types of R134a R152aR124yf and R1234ze(E) e compressor power con-sumption was influenced by varying evaporating tempera-ture for all investigated refrigerants as illustrated inFigure 12 Although the enthalpy difference (h2 minus h1) inEquation (4) decreases as the evaporating temperature in-creases the values of the compressor power increase as theevaporating temperature increases is can be explained onthe basis of equations (2) and (4) where the enthalpy dif-ference (h2 minus h1) decreases with the increase in the evapo-rating temperature while the volumetric efficiency increasesand the specific volume decreases in accordance with

0

05

1

15

2

25

3

15 20 25 30 35 40 45 50

Pow

er (k

W)

Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 8 Effect of condensing temperature on compressor powerfor investigated refrigerants

1

2

3

4

5

6

7

8

15 20 25 30 35 40 45 50

COP

Tc (degC)

Te = 10degCV = 00031m3s

R134aR152a

R1234yfR1234ze(E)

Figure 9 Effect of condensing temperature on COP for investi-gated refrigerants

2

3

4

5

6

7

8

9

10

15 20 25 30 35 40 45 50

R134aR152a

R1234yfR1234ze(E)

Coo

ling

capa

city

(kW

)

Tc (degC)

Figure 7 Effect of condensing temperature on cooling capacity forinvestigated refrigerants

Advances in Materials Science and Engineering 7

Equation (2) is led to an increase in mass flow rate beinggreater than the decrease in the enthalpy difference (h2 minus h1)and consequently the compressor power consumption in-creases with evaporating temperature is trend curveconfirmed with Li et al [17] and Llopis et al [26]

e compressor power of R134a and R1234yf was quitesimilar A reduction in a compressor power for R152a andR1234ze(E) by 8 and 26 respectively was occurred whencompared with R134a

ere are two important parameters that can charac-terize the most appropriate alternative refrigerants toR134a volumetric cooling capacity and discharge tem-perature Figure 13 illustrates the volumetric refrigerationcapacity (VCC) and the discharge temperature versus theevaporating temperature for all investigated refrigerantse volumetric refrigeration capacity expresses the coolingcapacity per unit volume at the exit of the evaporator Itindicates the volume of refrigerants handled by the com-pressor It was noted that R134a has the highest volumetriccooling capacity followed by R152a and R1234yf while theR1234ze(E) has lowest values of volumetric cooling ca-pacity is mean that the refrigerants R152a and R1234yfcan be replaced by R134a on the same compressor size inwhich the refrigerant R1234ze(E) needs to resize thecompressor for a given duty

It is necessary to study the discharge temperature for thelow-GWP refrigerant compared with R134a in order toclarify the steadiness and lifetime of the compressor

Referring to Figure 13 which illustrates the dischargetemperature versus the evaporating temperature for all in-vestigated refrigerants it was noted that the refrigerantR152a has the highest discharge temperature and it isimpediment in replacement between R152a and R134awhile the discharge temperature of R1234ze(E) and R1234yfis lower than that of R134a which is considered an advantagein replacement between R1234ze(E) R1234yf and R134a

e changing of the evaporating temperature affects theCOP of the system positively which is illustrated in Figure 14As the evaporating temperature increased the COP of therefrigeration system increased which can be attributed to theincrease in cooling capacity and was more rapid than theincrease in compressor powere refrigerant R1234ze(E) hasthe highest values of the COP among all the investigatedrefrigerants It was confirmed that the thermal performance ofthe R1234yf refrigerant (GWP100 358 times less than that ofR134a) was the closest to the thermal performance of theR134a system and therefore a more environmentally sus-tainable refrigerant for automotive air conditioning

e exergy destruction for the system compressor withdifferent evaporating temperatures is illustrated in Figure 15e highest exergy destruction through the compressor wasobtained for R1234ze(E) followed by R134a while R152a hasthe lowest values of exergy destruction Compared with thebase refrigerant of R134a the compressor exergy destructionof the refrigerant R1234ze(E) was higher by 65 while thecompressor exergy destruction of R1234yf and R152a wasreduced by 11 and 40 respectively e total exergy

0

02

04

06

08

1

12

E tot

al (k

W)

15 20 25 30 35 40 45 50Tc (degC)

Te = 10degCV = 00031m3s

R134aR152a

R1234yfR1234ze(E)

Figure 11 Total exergy destruction versus condensing temperature

005

01

015

02

025

03

035

04

15 20 25 30 35 40 45 50

E com

p (k

W)

Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degCV = 00031m3s

Figure 10 Exergy destruction in compressor versus condensingtemperature

8 Advances in Materials Science and Engineering

destruction of the all-cycle components for different types ofrefrigerants and the evaporating temperature is illustrated inFigure 16 e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the total exergydestruction of R1234yf and R152a was lower than that ofR134a by 15 and 45 respectively

623 4e Effect of Refrigerant Flow Rate e refrigerantvolume flow rate variation which was produced as a result ofvarying compressor speed which in turn was originated fromautomotive crankshaft speed affects the performance of theautomotive air conditioninge effect of varying volume flowrate on the cooling capacity and the coefficient of performanceis illustrated in Figures 17 and 18 for a typical condition ofTe 10degC and Tc 35degC e refrigerant mass flow rate variedas the RPM of the crankshaft was changed which depend on

Table 3 Results of the investigated refrigerants at different condensing temperatures

Item Tc oC R152a R1234yf R1234ze(E) R134a

Cooling capacity

30 660 669 561 69035 644 638 538 66540 624 606 515 63945 604 573 491 612

Compressor power

30 158 169 125 17135 1774 190 143 19440 1984 211 160 21545 2191 231 177 237

COP

30 418 396 447 40335 363 336 377 34440 315 288 322 29745 276 248 278 258

Total exergy destruction Etotal

30 0549 0851 0845 074835 0530 0812 0821 073040 0524 0780 0801 071045 0532 0770 0797 0701

Total exergy efficiency ηtotal

30 0322 028 0357 03435 0299 026 0336 03240 027 025 031 0345 0255 024 029 028

0

05

1

15

2

25

3

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Pow

er (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 12 Compressor power versus evaporating temperature

Disc

harg

e tem

pera

ture

(degC)

0

20

40

60

80

100

120

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Vol

umet

ric co

olin

g ca

paci

ty (k

Jm3 )

Te (degC)

VCC R134aVCC R152VCC R1234yfVCC R1234ze

Tdis R134aTdis R152aTdis R1234yfTdis R1234ze(E)

Figure 13 Effect of evaporating temperature on volumetriccooling capacity and discharge temperature

Advances in Materials Science and Engineering 9

the rate of fuel consumption of the automotive engine Inpractice the refrigerant mass flow rate ( _m ρ _v) which is therefrigerant density multiplied by volume flow rate affects thecooling capacity and compressor power according to equa-tions (1) and (2) in which the density varies according tovariation in evaporating temperature erefore the influenceof the refrigerant flow rate was evident to the coefficient ofperformance As the refrigerant flow rate increases the COPdecreases which can be explained by the increase in com-pressor power with a flow rate greater than the increase incooling capacity It is noted that the refrigerant R1234ze(E) hasthe highest COP between investigated refrigerants

e total exergy destruction of the compressor con-denser expansion valve and evaporator for the differentrefrigerant types is illustrated in Figure 19 e highestexergy destruction of the compressor was obtained forR1234ze(E) and the highest exergy destruction of thecondenser was obtained for R1234fy while the lowest valueof exergy destruction for the compressor and condenser wasobtained for R152a e highest values of the exergy de-struction for the evaporator and expansion valve were ob-tained for R1234ze(E) and R1234fy respectively

Exergy efficiency can give more logical ways to improvethe energy performance of automotive air conditioning Forthat reason the exergy analysis which was performed foreach cycle component should be considered integrated [6]Figures 20 and 21 show the total exergy efficiency with both

1

2

3

4

5

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

COP

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 14 COP versus evaporating temperature for Tc 35degC

005

01

015

02

025

03

035

04

ndash15 ndash10 ndash5 0 5 10 15 20

E com

p (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 15 Exergy destruction in compressor versus evaporatingtemperature

0

01

02

03

04

05

06

07

08

09

1

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

E tot

al

Figure 16 Total exergy destruction versus evaporatingtemperature

10 Advances in Materials Science and Engineering

0

1

2

3

4

5

6

7

8

0 05 1 15 2 25 3 35

Cool

ing

capa

city

(kW

)

V lowast 103 (m3s)

R134aR152a

R1234yfR1234ze(E)

Figure 17 Cooling capacity versus refrigerant flow rate at Tc 35degC

1

2

3

4

5

6

0 05 1 15 2 25 3 35

COP

R134aR152a

R1234yfR1234ze(E)

V lowast 103 (m3s)

Figure 18 COP versus refrigerant volume flow rate

Advances in Materials Science and Engineering 11

condensing and evaporating temperatures e total exergyefficiency was decreased with the condensing temperaturewhile it was increased with the evaporating temperature For

both condensing and evaporating temperatures the re-frigerant R1234yf has the lowest exergy efficiency followedby R152a e highest exergy efficiency was obtained withR1234ze(E) at different condensing temperatures while atdifferent evaporating temperatures the highest exergy effi-ciency was obtained for R134a From the environmentalthermal and exergy point of view the refrigerant R1234yfhas the best performance among all refrigerants that havebeen investigated to replace R134a in an automotive air-conditioning system

7 Conclusion

Energy and exergy analysis was presented for many envi-ronmentally friendly refrigerants as a drop-in replacementof current high-GWP of R134a in the automotive air-con-ditioning system ree alternative refrigerants which isdistinguished by zero ODP and GWP100lt 150 were inves-tigated with particular reference to the current R134a re-frigerant (GWP100 1430) e exergy destruction of eachcomponent and the exergy efficiency at different condensingtemperatures evaporating temperatures and refrigerantflow rates were presented and the main conclusions aresummarized as follows

(i) For all values of condensing and evaporatingtemperatures a higher system COP was obtained at

01

02

03

04

05

06

07

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degC V = 00031m3s

η tot

al

Figure 20 Total exergy efficiency versus condensing temperature

0

01

02

03

04

05

06

15 20 25 30 35 40 45 50Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degC V = 00031m3s

η tot

al

Figure 21 Total exergy efficiency versus evaporating temperature

R134a R152a R1234yf R1234ze

030

025

020

015

010

005

000

CompressorCondenser

ExpansionEvaporator

Figure 19 Total exergy destruction of each component for dif-ferent refrigerant types

12 Advances in Materials Science and Engineering

a lower compressor speed which was producedfrom slow crankshaft RPM

(ii) A reduction in the cooling capacity by 9 and inCOP by 27 was confirmed when a condensingtemperature increased by 5degC

(iii) Based on the test results the refrigerant R1234ze(E)had the highest coefficient of performance amongall investigated refrigerants

(iv) e refrigerant R1234yf was considered the closestin thermal performance to the refrigerant R134a

(v) e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the totalexergy destruction of R1234yf and R152a was lowerthan that of R134a by 15 and 45 respectively

(vi) e refrigerant R1234ze(E) was the most envi-ronmentally acceptable and had the best energeticand exergetic performance among all the testedrefrigerants

(vii) e highest exergy efficiency was obtained forR1234ze(E) at different condensing temperatureswhile at different evaporating temperatures thehighest exergy efficiency was obtained for R134a

Nomenclature

COP coefficient of performanceCP specific heat kJkgmiddotKEmiddot

x exergy kWh specific enthalpy kJkg_mref refrigerant flow rate kgsp refrigerant pressure kPaQ rate of heat transfer kWRPM revolution per minute minminus 1

s entropy kJkgmiddotKT temperature K_V refrigerant flow rate m3sVCC volumetric cooling capacity kJm3

W compressor power kWGWP100 global warming potential for 100 yearsΡ density kgm3

c coolingcomp compressorcond condenserexp expansionevap evaporatordest destructiondis dischargein inletis isentropicmech mechanicalo dead stateout outlet

Data Availability

e data that support the findings of this study are availableupon request from the corresponding author

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e authors would like to express their sincere gratitude tothe Public Authority for Applied Education and Training(PAAET) Kuwait for supporting and funding this workResearch Project No TS -16-12 Research Project TitleldquoEnergetic and exergetic analysis of R1234yf R1234ze andR152 as a low-GWP alternatives of R134a in automotive airconditioningrdquo Special appreciation to Refrigeration and AirConditioning Department Faculty of Industrial EducationHelwan University Egypt for the technical assistance ex-tended to the authors

References

[1] I P Koronaki D Cowan G Maidment et al ldquoRefrigerantemissions and leakage prevention across Europemdashresultsfrom the real skills Europe projectrdquo Energy vol 45 no 1pp 71ndash80 2012

[2] Environmental Protection Agency Protection of StratosphericOzone Change of Listing Status for Certain Substitutes underthe Significant New Alternatives Policy Program Rules andRegulations Environmental Protection Agency EPAWashington DC USA 2015

[3] I Dincer and A R Marc Exergy Energy Environment andSustainable Development Elsevier Amsterdam NetherlandsSecond edition 2016

[4] H Cho and C Park ldquoExperimental investigation of perfor-mance and exergy analysis of automotive air conditioningsystems using refrigerant R1234yf at various compressorspeedsrdquo Applied 4ermal Engineering vol 101 pp 30ndash372016

[5] B Jemaa R Mansouri I Boukholda and A Bellagi ldquoEnergyand exergy investigation of R1234ze(E) as R134a replacementin vapor compression chillersrdquo International Journal of Hy-drogen Energy vol 42 no 17 pp 12877ndash12887 2017

[6] K Zhang Y Zhu J Liu X Niu and X Yuan ldquoExergy andenergy analysis of a double evaporating temperature chillerrdquoEnergy and Buildings vol 165 pp 464ndash471 2018

[7] J K Verma A Satsangi and V Chaturani ldquoA review ofalternative to R134a (CH3CH2F) refrigerantrdquo InternationalJournal of Emerging Technology and Advanced Engineeringvol 3 no 1 pp 300ndash304 2013

[8] J Garcia T Ali W M Duarte A Khosravi and L MachadoldquoComparison of transient response of an evaporatormodel forwater refrigeration system working with R1234yf as a drop-inreplacement for R134ardquo International Journal of Refrigera-tion vol 91 pp 211ndash222 2018

[9] E Navarro I O Martınez-Galvan J Nohales andJ Gonzalvez-Macia ldquoComparative experimental study of anopen piston compressor working with R-1234yf R-134a andR-290rdquo International Journal of Refrigeration vol 36 no 3pp 768ndash775 2013

[10] J Navarro-Esbrı J M Mendoza-Miranda A Mota-BabiloniA Barraga-Cervera A Barragan-Cervera and J M Belman-Flores ldquoExperimental analysis of R1234yf as a drop-in re-placement for R134a in a vapor compression systemrdquo In-ternational Journal of Refrigeration vol 36 no 3pp 870ndash880 2013

Advances in Materials Science and Engineering 13

[11] A Gomaa ldquoPerformance characteristics of automotive airconditioning system with refrigerant R134a and its alterna-tivesrdquo International Journal of Energy and Power Engineeringvol 4 no 3 pp 168ndash177 2015

[12] Y Lee and D Jung ldquoA brief performance comparison ofR1234yf and R134a in a bench tester for automobile appli-cationsrdquo Applied 4ermal Engineering vol 35 pp 240ndash2422012

[13] J M Belman-Flores V H Rangel-Hernandez S Uson andC Rubio-Maya ldquoEnergy and exergy analysis of R1234yf asdrop-in replacement for R134a in a domestic refrigerationsystemrdquo Energy vol 132 pp 116ndash125 2017

[14] M Joybari M H Hatamipour A Rahimi and F ModarresldquoExergy analysis and optimization of R600a as a replacementof R134a in a domestic refrigerator systemrdquo InternationalJournal of Refrigeration vol 36 no 4 pp 1233ndash1242 2013

[15] D Sanchez R Cabello R Llopis I Arauzo J Catalan-Giland E Torrella ldquoEnergy performance evaluation of R1234yfR1234ze(E) R600a R290 and R152a as low-GWP R134aalternativesrdquo International Journal of Refrigeration vol 74pp 269ndash282 2017

[16] S V Shaik and T P Ashok Babu ldquoeoretical computation ofperformance of sustainable energy efficient R22 alternativesfor residential air conditionersrdquo Energy Procedia vol 138pp 710ndash716 2017

[17] Z Li H Jiang X Chen and K Liang ldquoComparative study onenergy efficiency of low GWP refrigerants in domestic re-frigerators with capacity modulationrdquo Energy and Buildingsvol 192 pp 93ndash100 2019

[18] S S Vali T P Setty and A Babu ldquoAnalytical computation ofthermodynamic performance parameters of actual vapourcompression refrigeration system with R22 R32 R134aR152a R290 and R1270rdquo MATEC Web of Conferencesvol 144 Article ID 04009 2018

[19] G Relue and S Kopchick New Refrigerants Designation andSafety Classifications E360 Forum Emerson Raleigh NCUSA 2017

[20] ASHRAE Standard 34Designation and Safety Classification ofRefrigerants American Society of Heating Ventilating andAir-Conditioning Engineers Atlanta GA USA 2010

[21] J P Holman Experimental Method for Engineerspp 62ndash65McGraw-Hill Book Company New York NY USA Eighthedition 2001

[22] B O Bolaji ldquoExperimental study of R152a and R32 to replaceR134a in a domestic refrigeratorrdquo Energy vol 35 no 9pp 3793ndash3798 2010

[23] M Fatouh A I Eid and N Nabil ldquoPerformance of water-to-water vapor compression refrigeration system using R22 al-ternatives part I system simulationrdquo Engineering ResearchJournal vol 124 pp M19ndashM43 2009

[24] A Yataganbaba A Kilicarslan and I Kurtbas ldquoExergyanalysis of R1234yf and R1234ze as R134a replacements in atwo evaporator vapour compression refrigeration systemrdquoInternational Journal of Refrigeration vol 60 pp 26ndash37 2015

[25] G F Nellis and S A Klein Engineering Equation Solver (EES)F-Chart Software Wiley Middleton WI USA 2013

[26] R Llopis E Torrella R Cabello and D Sanchez ldquoPerfor-mance evaluation of R404A and R507A refrigerant mixturesin an experimental double-stage vapour compression plantrdquoApplied Energy vol 87 no 5 pp 1546ndash1553 2010

14 Advances in Materials Science and Engineering

R152a R1234yf and R1234ze(E) were investigated incomparison with a current high-GWP refrigerant of R134a

62 Performance Criteria of Investigated Refrigerants eperformance criteria of the low GWP refrigerants of R152aR1234yf and R1234ze(E) compared with R134a werespecified to the effect of evaporating temperature con-densing temperature and refrigerant flow rate on the en-ergetic and exegetic parameters of the automotive airconditioning system In particular the most possible drop-inreplacement refrigerant to R134a in automotive air condi-tioning application was R152a (GWP100 less 10 times)R1234yf (GWP100 less 358 times) and R1234ze(E) (GWP100less 238 times)

621 4e Effect of Condensing Temperature In particularthe variation of the condensing temperature through the daymonth and season affects the system performance thereforea wide range of condensing temperature 20degCleTcle 45degC wasconsidered Figure 7 illustrates the cooling capacity of dif-ferent refrigerant types at Te 10degC and _V 00031m3s Atthe same operating condition it was noted that a reduction incooling capacity was recorded for R152a R1234yf andR1234ze(E) compared with R134a by 36 38 and 19respectively e compressor power was impacted by

changing of condensing temperature for different refrigeranttypes which is illustrated in Figure 8 At the same operatingcondition the compressor power consumption of R134a washigher than that of R152a R1234yf and R1234ze(E) by 8516 and 28 respectively It has been shown that the re-frigerant R134a has higher values of both refrigeration ca-pacity and compressor power than the proposed refrigerantsat the same operating condition In this case the coefficient ofperformance (COP) is themost important factor to determinethe performance characteristics of the proposed refrigerantswhich is illustrated in Figure 9 e COP of R134a was lowerthan that of R1234ze(E) and R152a by 108 and 56 re-spectively It was confirmed that the COP of the refrigerantR1234yf wasvery close to the performance of R134a in whichthe COP of R134a was higher by 2

e exergy destruction of the system compressor withdifferent condensing temperatures is shown in Figure 10e highest exergy destruction through the compressor wasobtained for R1234yf followed by R134a while R152a has thelowest values of exergy destruction Compared with the baserefrigerant of R134a the compressor exergy destruction ofthe refrigerant R1234ze(E) was higher by 6 while a re-duction in the compressor exergy destruction was obtainedby 14 and 29 for the refrigerants R1234yf and R152arespectively compared with R134a e exergy destructionof the evaporator expansion valve and condenser was alsocalculated to form the total exergy destructione variationof the total exergy destruction of all refrigeration cyclecomponents with the condensing temperature is illustrated

0

1

2

3

4

5

6

7

8

0

1

2

3

4

5

6

7

8

9

10

0 500 1000 1500 2000RPM

Qevap Tc = 25degCQevap Tc = 35degCQevap Tc = 45degC

COP Tc = 25degCCOP Tc = 35degCCOP Tc = 45degC

COP

Qev

a (kW

)

Figure 6 Cooling capacity and COP versus RPM of R134a (ex-perimental results)

0 300 600 900 1200 1500 1800RPM

3

25

2

15

1

05

0

Pow

er (k

W)

Tc = 25degCTc = 30degCTc = 35degC

Tc = 40degCTc = 45degC

Figure 5 Compressor power versus RPM of R134a (experimentalresults)

6 Advances in Materials Science and Engineering

in Figure 11 e total exergy destruction of R1234yf andR1234ze(E) was quite similar in which the total exergydestruction of both refrigerants were higher than that ofR134a by 12 while the total exergy destruction of R152awas lower than that of R134a by 26

e effect of varying condensing temperature on theenergy and exergy parameters is summarized as a sample ofresults in Table 3

622 4e Effect of Evaporating Temperature e evapo-rating temperature was different from one application toanother and it should be noted that the evaporating tem-perature affects the system performance positively A widerange of evaporating temperatures which were applied inmany air conditioning applications (minus 15degC to 15degC) wastested for different refrigerant types of R134a R152aR124yf and R1234ze(E) e compressor power con-sumption was influenced by varying evaporating tempera-ture for all investigated refrigerants as illustrated inFigure 12 Although the enthalpy difference (h2 minus h1) inEquation (4) decreases as the evaporating temperature in-creases the values of the compressor power increase as theevaporating temperature increases is can be explained onthe basis of equations (2) and (4) where the enthalpy dif-ference (h2 minus h1) decreases with the increase in the evapo-rating temperature while the volumetric efficiency increasesand the specific volume decreases in accordance with

0

05

1

15

2

25

3

15 20 25 30 35 40 45 50

Pow

er (k

W)

Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 8 Effect of condensing temperature on compressor powerfor investigated refrigerants

1

2

3

4

5

6

7

8

15 20 25 30 35 40 45 50

COP

Tc (degC)

Te = 10degCV = 00031m3s

R134aR152a

R1234yfR1234ze(E)

Figure 9 Effect of condensing temperature on COP for investi-gated refrigerants

2

3

4

5

6

7

8

9

10

15 20 25 30 35 40 45 50

R134aR152a

R1234yfR1234ze(E)

Coo

ling

capa

city

(kW

)

Tc (degC)

Figure 7 Effect of condensing temperature on cooling capacity forinvestigated refrigerants

Advances in Materials Science and Engineering 7

Equation (2) is led to an increase in mass flow rate beinggreater than the decrease in the enthalpy difference (h2 minus h1)and consequently the compressor power consumption in-creases with evaporating temperature is trend curveconfirmed with Li et al [17] and Llopis et al [26]

e compressor power of R134a and R1234yf was quitesimilar A reduction in a compressor power for R152a andR1234ze(E) by 8 and 26 respectively was occurred whencompared with R134a

ere are two important parameters that can charac-terize the most appropriate alternative refrigerants toR134a volumetric cooling capacity and discharge tem-perature Figure 13 illustrates the volumetric refrigerationcapacity (VCC) and the discharge temperature versus theevaporating temperature for all investigated refrigerantse volumetric refrigeration capacity expresses the coolingcapacity per unit volume at the exit of the evaporator Itindicates the volume of refrigerants handled by the com-pressor It was noted that R134a has the highest volumetriccooling capacity followed by R152a and R1234yf while theR1234ze(E) has lowest values of volumetric cooling ca-pacity is mean that the refrigerants R152a and R1234yfcan be replaced by R134a on the same compressor size inwhich the refrigerant R1234ze(E) needs to resize thecompressor for a given duty

It is necessary to study the discharge temperature for thelow-GWP refrigerant compared with R134a in order toclarify the steadiness and lifetime of the compressor

Referring to Figure 13 which illustrates the dischargetemperature versus the evaporating temperature for all in-vestigated refrigerants it was noted that the refrigerantR152a has the highest discharge temperature and it isimpediment in replacement between R152a and R134awhile the discharge temperature of R1234ze(E) and R1234yfis lower than that of R134a which is considered an advantagein replacement between R1234ze(E) R1234yf and R134a

e changing of the evaporating temperature affects theCOP of the system positively which is illustrated in Figure 14As the evaporating temperature increased the COP of therefrigeration system increased which can be attributed to theincrease in cooling capacity and was more rapid than theincrease in compressor powere refrigerant R1234ze(E) hasthe highest values of the COP among all the investigatedrefrigerants It was confirmed that the thermal performance ofthe R1234yf refrigerant (GWP100 358 times less than that ofR134a) was the closest to the thermal performance of theR134a system and therefore a more environmentally sus-tainable refrigerant for automotive air conditioning

e exergy destruction for the system compressor withdifferent evaporating temperatures is illustrated in Figure 15e highest exergy destruction through the compressor wasobtained for R1234ze(E) followed by R134a while R152a hasthe lowest values of exergy destruction Compared with thebase refrigerant of R134a the compressor exergy destructionof the refrigerant R1234ze(E) was higher by 65 while thecompressor exergy destruction of R1234yf and R152a wasreduced by 11 and 40 respectively e total exergy

0

02

04

06

08

1

12

E tot

al (k

W)

15 20 25 30 35 40 45 50Tc (degC)

Te = 10degCV = 00031m3s

R134aR152a

R1234yfR1234ze(E)

Figure 11 Total exergy destruction versus condensing temperature

005

01

015

02

025

03

035

04

15 20 25 30 35 40 45 50

E com

p (k

W)

Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degCV = 00031m3s

Figure 10 Exergy destruction in compressor versus condensingtemperature

8 Advances in Materials Science and Engineering

destruction of the all-cycle components for different types ofrefrigerants and the evaporating temperature is illustrated inFigure 16 e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the total exergydestruction of R1234yf and R152a was lower than that ofR134a by 15 and 45 respectively

623 4e Effect of Refrigerant Flow Rate e refrigerantvolume flow rate variation which was produced as a result ofvarying compressor speed which in turn was originated fromautomotive crankshaft speed affects the performance of theautomotive air conditioninge effect of varying volume flowrate on the cooling capacity and the coefficient of performanceis illustrated in Figures 17 and 18 for a typical condition ofTe 10degC and Tc 35degC e refrigerant mass flow rate variedas the RPM of the crankshaft was changed which depend on

Table 3 Results of the investigated refrigerants at different condensing temperatures

Item Tc oC R152a R1234yf R1234ze(E) R134a

Cooling capacity

30 660 669 561 69035 644 638 538 66540 624 606 515 63945 604 573 491 612

Compressor power

30 158 169 125 17135 1774 190 143 19440 1984 211 160 21545 2191 231 177 237

COP

30 418 396 447 40335 363 336 377 34440 315 288 322 29745 276 248 278 258

Total exergy destruction Etotal

30 0549 0851 0845 074835 0530 0812 0821 073040 0524 0780 0801 071045 0532 0770 0797 0701

Total exergy efficiency ηtotal

30 0322 028 0357 03435 0299 026 0336 03240 027 025 031 0345 0255 024 029 028

0

05

1

15

2

25

3

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Pow

er (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 12 Compressor power versus evaporating temperature

Disc

harg

e tem

pera

ture

(degC)

0

20

40

60

80

100

120

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Vol

umet

ric co

olin

g ca

paci

ty (k

Jm3 )

Te (degC)

VCC R134aVCC R152VCC R1234yfVCC R1234ze

Tdis R134aTdis R152aTdis R1234yfTdis R1234ze(E)

Figure 13 Effect of evaporating temperature on volumetriccooling capacity and discharge temperature

Advances in Materials Science and Engineering 9

the rate of fuel consumption of the automotive engine Inpractice the refrigerant mass flow rate ( _m ρ _v) which is therefrigerant density multiplied by volume flow rate affects thecooling capacity and compressor power according to equa-tions (1) and (2) in which the density varies according tovariation in evaporating temperature erefore the influenceof the refrigerant flow rate was evident to the coefficient ofperformance As the refrigerant flow rate increases the COPdecreases which can be explained by the increase in com-pressor power with a flow rate greater than the increase incooling capacity It is noted that the refrigerant R1234ze(E) hasthe highest COP between investigated refrigerants

e total exergy destruction of the compressor con-denser expansion valve and evaporator for the differentrefrigerant types is illustrated in Figure 19 e highestexergy destruction of the compressor was obtained forR1234ze(E) and the highest exergy destruction of thecondenser was obtained for R1234fy while the lowest valueof exergy destruction for the compressor and condenser wasobtained for R152a e highest values of the exergy de-struction for the evaporator and expansion valve were ob-tained for R1234ze(E) and R1234fy respectively

Exergy efficiency can give more logical ways to improvethe energy performance of automotive air conditioning Forthat reason the exergy analysis which was performed foreach cycle component should be considered integrated [6]Figures 20 and 21 show the total exergy efficiency with both

1

2

3

4

5

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

COP

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 14 COP versus evaporating temperature for Tc 35degC

005

01

015

02

025

03

035

04

ndash15 ndash10 ndash5 0 5 10 15 20

E com

p (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 15 Exergy destruction in compressor versus evaporatingtemperature

0

01

02

03

04

05

06

07

08

09

1

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

E tot

al

Figure 16 Total exergy destruction versus evaporatingtemperature

10 Advances in Materials Science and Engineering

0

1

2

3

4

5

6

7

8

0 05 1 15 2 25 3 35

Cool

ing

capa

city

(kW

)

V lowast 103 (m3s)

R134aR152a

R1234yfR1234ze(E)

Figure 17 Cooling capacity versus refrigerant flow rate at Tc 35degC

1

2

3

4

5

6

0 05 1 15 2 25 3 35

COP

R134aR152a

R1234yfR1234ze(E)

V lowast 103 (m3s)

Figure 18 COP versus refrigerant volume flow rate

Advances in Materials Science and Engineering 11

condensing and evaporating temperatures e total exergyefficiency was decreased with the condensing temperaturewhile it was increased with the evaporating temperature For

both condensing and evaporating temperatures the re-frigerant R1234yf has the lowest exergy efficiency followedby R152a e highest exergy efficiency was obtained withR1234ze(E) at different condensing temperatures while atdifferent evaporating temperatures the highest exergy effi-ciency was obtained for R134a From the environmentalthermal and exergy point of view the refrigerant R1234yfhas the best performance among all refrigerants that havebeen investigated to replace R134a in an automotive air-conditioning system

7 Conclusion

Energy and exergy analysis was presented for many envi-ronmentally friendly refrigerants as a drop-in replacementof current high-GWP of R134a in the automotive air-con-ditioning system ree alternative refrigerants which isdistinguished by zero ODP and GWP100lt 150 were inves-tigated with particular reference to the current R134a re-frigerant (GWP100 1430) e exergy destruction of eachcomponent and the exergy efficiency at different condensingtemperatures evaporating temperatures and refrigerantflow rates were presented and the main conclusions aresummarized as follows

(i) For all values of condensing and evaporatingtemperatures a higher system COP was obtained at

01

02

03

04

05

06

07

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degC V = 00031m3s

η tot

al

Figure 20 Total exergy efficiency versus condensing temperature

0

01

02

03

04

05

06

15 20 25 30 35 40 45 50Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degC V = 00031m3s

η tot

al

Figure 21 Total exergy efficiency versus evaporating temperature

R134a R152a R1234yf R1234ze

030

025

020

015

010

005

000

CompressorCondenser

ExpansionEvaporator

Figure 19 Total exergy destruction of each component for dif-ferent refrigerant types

12 Advances in Materials Science and Engineering

a lower compressor speed which was producedfrom slow crankshaft RPM

(ii) A reduction in the cooling capacity by 9 and inCOP by 27 was confirmed when a condensingtemperature increased by 5degC

(iii) Based on the test results the refrigerant R1234ze(E)had the highest coefficient of performance amongall investigated refrigerants

(iv) e refrigerant R1234yf was considered the closestin thermal performance to the refrigerant R134a

(v) e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the totalexergy destruction of R1234yf and R152a was lowerthan that of R134a by 15 and 45 respectively

(vi) e refrigerant R1234ze(E) was the most envi-ronmentally acceptable and had the best energeticand exergetic performance among all the testedrefrigerants

(vii) e highest exergy efficiency was obtained forR1234ze(E) at different condensing temperatureswhile at different evaporating temperatures thehighest exergy efficiency was obtained for R134a

Nomenclature

COP coefficient of performanceCP specific heat kJkgmiddotKEmiddot

x exergy kWh specific enthalpy kJkg_mref refrigerant flow rate kgsp refrigerant pressure kPaQ rate of heat transfer kWRPM revolution per minute minminus 1

s entropy kJkgmiddotKT temperature K_V refrigerant flow rate m3sVCC volumetric cooling capacity kJm3

W compressor power kWGWP100 global warming potential for 100 yearsΡ density kgm3

c coolingcomp compressorcond condenserexp expansionevap evaporatordest destructiondis dischargein inletis isentropicmech mechanicalo dead stateout outlet

Data Availability

e data that support the findings of this study are availableupon request from the corresponding author

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e authors would like to express their sincere gratitude tothe Public Authority for Applied Education and Training(PAAET) Kuwait for supporting and funding this workResearch Project No TS -16-12 Research Project TitleldquoEnergetic and exergetic analysis of R1234yf R1234ze andR152 as a low-GWP alternatives of R134a in automotive airconditioningrdquo Special appreciation to Refrigeration and AirConditioning Department Faculty of Industrial EducationHelwan University Egypt for the technical assistance ex-tended to the authors

References

[1] I P Koronaki D Cowan G Maidment et al ldquoRefrigerantemissions and leakage prevention across Europemdashresultsfrom the real skills Europe projectrdquo Energy vol 45 no 1pp 71ndash80 2012

[2] Environmental Protection Agency Protection of StratosphericOzone Change of Listing Status for Certain Substitutes underthe Significant New Alternatives Policy Program Rules andRegulations Environmental Protection Agency EPAWashington DC USA 2015

[3] I Dincer and A R Marc Exergy Energy Environment andSustainable Development Elsevier Amsterdam NetherlandsSecond edition 2016

[4] H Cho and C Park ldquoExperimental investigation of perfor-mance and exergy analysis of automotive air conditioningsystems using refrigerant R1234yf at various compressorspeedsrdquo Applied 4ermal Engineering vol 101 pp 30ndash372016

[5] B Jemaa R Mansouri I Boukholda and A Bellagi ldquoEnergyand exergy investigation of R1234ze(E) as R134a replacementin vapor compression chillersrdquo International Journal of Hy-drogen Energy vol 42 no 17 pp 12877ndash12887 2017

[6] K Zhang Y Zhu J Liu X Niu and X Yuan ldquoExergy andenergy analysis of a double evaporating temperature chillerrdquoEnergy and Buildings vol 165 pp 464ndash471 2018

[7] J K Verma A Satsangi and V Chaturani ldquoA review ofalternative to R134a (CH3CH2F) refrigerantrdquo InternationalJournal of Emerging Technology and Advanced Engineeringvol 3 no 1 pp 300ndash304 2013

[8] J Garcia T Ali W M Duarte A Khosravi and L MachadoldquoComparison of transient response of an evaporatormodel forwater refrigeration system working with R1234yf as a drop-inreplacement for R134ardquo International Journal of Refrigera-tion vol 91 pp 211ndash222 2018

[9] E Navarro I O Martınez-Galvan J Nohales andJ Gonzalvez-Macia ldquoComparative experimental study of anopen piston compressor working with R-1234yf R-134a andR-290rdquo International Journal of Refrigeration vol 36 no 3pp 768ndash775 2013

[10] J Navarro-Esbrı J M Mendoza-Miranda A Mota-BabiloniA Barraga-Cervera A Barragan-Cervera and J M Belman-Flores ldquoExperimental analysis of R1234yf as a drop-in re-placement for R134a in a vapor compression systemrdquo In-ternational Journal of Refrigeration vol 36 no 3pp 870ndash880 2013

Advances in Materials Science and Engineering 13

[11] A Gomaa ldquoPerformance characteristics of automotive airconditioning system with refrigerant R134a and its alterna-tivesrdquo International Journal of Energy and Power Engineeringvol 4 no 3 pp 168ndash177 2015

[12] Y Lee and D Jung ldquoA brief performance comparison ofR1234yf and R134a in a bench tester for automobile appli-cationsrdquo Applied 4ermal Engineering vol 35 pp 240ndash2422012

[13] J M Belman-Flores V H Rangel-Hernandez S Uson andC Rubio-Maya ldquoEnergy and exergy analysis of R1234yf asdrop-in replacement for R134a in a domestic refrigerationsystemrdquo Energy vol 132 pp 116ndash125 2017

[14] M Joybari M H Hatamipour A Rahimi and F ModarresldquoExergy analysis and optimization of R600a as a replacementof R134a in a domestic refrigerator systemrdquo InternationalJournal of Refrigeration vol 36 no 4 pp 1233ndash1242 2013

[15] D Sanchez R Cabello R Llopis I Arauzo J Catalan-Giland E Torrella ldquoEnergy performance evaluation of R1234yfR1234ze(E) R600a R290 and R152a as low-GWP R134aalternativesrdquo International Journal of Refrigeration vol 74pp 269ndash282 2017

[16] S V Shaik and T P Ashok Babu ldquoeoretical computation ofperformance of sustainable energy efficient R22 alternativesfor residential air conditionersrdquo Energy Procedia vol 138pp 710ndash716 2017

[17] Z Li H Jiang X Chen and K Liang ldquoComparative study onenergy efficiency of low GWP refrigerants in domestic re-frigerators with capacity modulationrdquo Energy and Buildingsvol 192 pp 93ndash100 2019

[18] S S Vali T P Setty and A Babu ldquoAnalytical computation ofthermodynamic performance parameters of actual vapourcompression refrigeration system with R22 R32 R134aR152a R290 and R1270rdquo MATEC Web of Conferencesvol 144 Article ID 04009 2018

[19] G Relue and S Kopchick New Refrigerants Designation andSafety Classifications E360 Forum Emerson Raleigh NCUSA 2017

[20] ASHRAE Standard 34Designation and Safety Classification ofRefrigerants American Society of Heating Ventilating andAir-Conditioning Engineers Atlanta GA USA 2010

[21] J P Holman Experimental Method for Engineerspp 62ndash65McGraw-Hill Book Company New York NY USA Eighthedition 2001

[22] B O Bolaji ldquoExperimental study of R152a and R32 to replaceR134a in a domestic refrigeratorrdquo Energy vol 35 no 9pp 3793ndash3798 2010

[23] M Fatouh A I Eid and N Nabil ldquoPerformance of water-to-water vapor compression refrigeration system using R22 al-ternatives part I system simulationrdquo Engineering ResearchJournal vol 124 pp M19ndashM43 2009

[24] A Yataganbaba A Kilicarslan and I Kurtbas ldquoExergyanalysis of R1234yf and R1234ze as R134a replacements in atwo evaporator vapour compression refrigeration systemrdquoInternational Journal of Refrigeration vol 60 pp 26ndash37 2015

[25] G F Nellis and S A Klein Engineering Equation Solver (EES)F-Chart Software Wiley Middleton WI USA 2013

[26] R Llopis E Torrella R Cabello and D Sanchez ldquoPerfor-mance evaluation of R404A and R507A refrigerant mixturesin an experimental double-stage vapour compression plantrdquoApplied Energy vol 87 no 5 pp 1546ndash1553 2010

14 Advances in Materials Science and Engineering

in Figure 11 e total exergy destruction of R1234yf andR1234ze(E) was quite similar in which the total exergydestruction of both refrigerants were higher than that ofR134a by 12 while the total exergy destruction of R152awas lower than that of R134a by 26

e effect of varying condensing temperature on theenergy and exergy parameters is summarized as a sample ofresults in Table 3

622 4e Effect of Evaporating Temperature e evapo-rating temperature was different from one application toanother and it should be noted that the evaporating tem-perature affects the system performance positively A widerange of evaporating temperatures which were applied inmany air conditioning applications (minus 15degC to 15degC) wastested for different refrigerant types of R134a R152aR124yf and R1234ze(E) e compressor power con-sumption was influenced by varying evaporating tempera-ture for all investigated refrigerants as illustrated inFigure 12 Although the enthalpy difference (h2 minus h1) inEquation (4) decreases as the evaporating temperature in-creases the values of the compressor power increase as theevaporating temperature increases is can be explained onthe basis of equations (2) and (4) where the enthalpy dif-ference (h2 minus h1) decreases with the increase in the evapo-rating temperature while the volumetric efficiency increasesand the specific volume decreases in accordance with

0

05

1

15

2

25

3

15 20 25 30 35 40 45 50

Pow

er (k

W)

Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 8 Effect of condensing temperature on compressor powerfor investigated refrigerants

1

2

3

4

5

6

7

8

15 20 25 30 35 40 45 50

COP

Tc (degC)

Te = 10degCV = 00031m3s

R134aR152a

R1234yfR1234ze(E)

Figure 9 Effect of condensing temperature on COP for investi-gated refrigerants

2

3

4

5

6

7

8

9

10

15 20 25 30 35 40 45 50

R134aR152a

R1234yfR1234ze(E)

Coo

ling

capa

city

(kW

)

Tc (degC)

Figure 7 Effect of condensing temperature on cooling capacity forinvestigated refrigerants

Advances in Materials Science and Engineering 7

Equation (2) is led to an increase in mass flow rate beinggreater than the decrease in the enthalpy difference (h2 minus h1)and consequently the compressor power consumption in-creases with evaporating temperature is trend curveconfirmed with Li et al [17] and Llopis et al [26]

e compressor power of R134a and R1234yf was quitesimilar A reduction in a compressor power for R152a andR1234ze(E) by 8 and 26 respectively was occurred whencompared with R134a

ere are two important parameters that can charac-terize the most appropriate alternative refrigerants toR134a volumetric cooling capacity and discharge tem-perature Figure 13 illustrates the volumetric refrigerationcapacity (VCC) and the discharge temperature versus theevaporating temperature for all investigated refrigerantse volumetric refrigeration capacity expresses the coolingcapacity per unit volume at the exit of the evaporator Itindicates the volume of refrigerants handled by the com-pressor It was noted that R134a has the highest volumetriccooling capacity followed by R152a and R1234yf while theR1234ze(E) has lowest values of volumetric cooling ca-pacity is mean that the refrigerants R152a and R1234yfcan be replaced by R134a on the same compressor size inwhich the refrigerant R1234ze(E) needs to resize thecompressor for a given duty

It is necessary to study the discharge temperature for thelow-GWP refrigerant compared with R134a in order toclarify the steadiness and lifetime of the compressor

Referring to Figure 13 which illustrates the dischargetemperature versus the evaporating temperature for all in-vestigated refrigerants it was noted that the refrigerantR152a has the highest discharge temperature and it isimpediment in replacement between R152a and R134awhile the discharge temperature of R1234ze(E) and R1234yfis lower than that of R134a which is considered an advantagein replacement between R1234ze(E) R1234yf and R134a

e changing of the evaporating temperature affects theCOP of the system positively which is illustrated in Figure 14As the evaporating temperature increased the COP of therefrigeration system increased which can be attributed to theincrease in cooling capacity and was more rapid than theincrease in compressor powere refrigerant R1234ze(E) hasthe highest values of the COP among all the investigatedrefrigerants It was confirmed that the thermal performance ofthe R1234yf refrigerant (GWP100 358 times less than that ofR134a) was the closest to the thermal performance of theR134a system and therefore a more environmentally sus-tainable refrigerant for automotive air conditioning

e exergy destruction for the system compressor withdifferent evaporating temperatures is illustrated in Figure 15e highest exergy destruction through the compressor wasobtained for R1234ze(E) followed by R134a while R152a hasthe lowest values of exergy destruction Compared with thebase refrigerant of R134a the compressor exergy destructionof the refrigerant R1234ze(E) was higher by 65 while thecompressor exergy destruction of R1234yf and R152a wasreduced by 11 and 40 respectively e total exergy

0

02

04

06

08

1

12

E tot

al (k

W)

15 20 25 30 35 40 45 50Tc (degC)

Te = 10degCV = 00031m3s

R134aR152a

R1234yfR1234ze(E)

Figure 11 Total exergy destruction versus condensing temperature

005

01

015

02

025

03

035

04

15 20 25 30 35 40 45 50

E com

p (k

W)

Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degCV = 00031m3s

Figure 10 Exergy destruction in compressor versus condensingtemperature

8 Advances in Materials Science and Engineering

destruction of the all-cycle components for different types ofrefrigerants and the evaporating temperature is illustrated inFigure 16 e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the total exergydestruction of R1234yf and R152a was lower than that ofR134a by 15 and 45 respectively

623 4e Effect of Refrigerant Flow Rate e refrigerantvolume flow rate variation which was produced as a result ofvarying compressor speed which in turn was originated fromautomotive crankshaft speed affects the performance of theautomotive air conditioninge effect of varying volume flowrate on the cooling capacity and the coefficient of performanceis illustrated in Figures 17 and 18 for a typical condition ofTe 10degC and Tc 35degC e refrigerant mass flow rate variedas the RPM of the crankshaft was changed which depend on

Table 3 Results of the investigated refrigerants at different condensing temperatures

Item Tc oC R152a R1234yf R1234ze(E) R134a

Cooling capacity

30 660 669 561 69035 644 638 538 66540 624 606 515 63945 604 573 491 612

Compressor power

30 158 169 125 17135 1774 190 143 19440 1984 211 160 21545 2191 231 177 237

COP

30 418 396 447 40335 363 336 377 34440 315 288 322 29745 276 248 278 258

Total exergy destruction Etotal

30 0549 0851 0845 074835 0530 0812 0821 073040 0524 0780 0801 071045 0532 0770 0797 0701

Total exergy efficiency ηtotal

30 0322 028 0357 03435 0299 026 0336 03240 027 025 031 0345 0255 024 029 028

0

05

1

15

2

25

3

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Pow

er (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 12 Compressor power versus evaporating temperature

Disc

harg

e tem

pera

ture

(degC)

0

20

40

60

80

100

120

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Vol

umet

ric co

olin

g ca

paci

ty (k

Jm3 )

Te (degC)

VCC R134aVCC R152VCC R1234yfVCC R1234ze

Tdis R134aTdis R152aTdis R1234yfTdis R1234ze(E)

Figure 13 Effect of evaporating temperature on volumetriccooling capacity and discharge temperature

Advances in Materials Science and Engineering 9

the rate of fuel consumption of the automotive engine Inpractice the refrigerant mass flow rate ( _m ρ _v) which is therefrigerant density multiplied by volume flow rate affects thecooling capacity and compressor power according to equa-tions (1) and (2) in which the density varies according tovariation in evaporating temperature erefore the influenceof the refrigerant flow rate was evident to the coefficient ofperformance As the refrigerant flow rate increases the COPdecreases which can be explained by the increase in com-pressor power with a flow rate greater than the increase incooling capacity It is noted that the refrigerant R1234ze(E) hasthe highest COP between investigated refrigerants

e total exergy destruction of the compressor con-denser expansion valve and evaporator for the differentrefrigerant types is illustrated in Figure 19 e highestexergy destruction of the compressor was obtained forR1234ze(E) and the highest exergy destruction of thecondenser was obtained for R1234fy while the lowest valueof exergy destruction for the compressor and condenser wasobtained for R152a e highest values of the exergy de-struction for the evaporator and expansion valve were ob-tained for R1234ze(E) and R1234fy respectively

Exergy efficiency can give more logical ways to improvethe energy performance of automotive air conditioning Forthat reason the exergy analysis which was performed foreach cycle component should be considered integrated [6]Figures 20 and 21 show the total exergy efficiency with both

1

2

3

4

5

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

COP

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 14 COP versus evaporating temperature for Tc 35degC

005

01

015

02

025

03

035

04

ndash15 ndash10 ndash5 0 5 10 15 20

E com

p (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 15 Exergy destruction in compressor versus evaporatingtemperature

0

01

02

03

04

05

06

07

08

09

1

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

E tot

al

Figure 16 Total exergy destruction versus evaporatingtemperature

10 Advances in Materials Science and Engineering

0

1

2

3

4

5

6

7

8

0 05 1 15 2 25 3 35

Cool

ing

capa

city

(kW

)

V lowast 103 (m3s)

R134aR152a

R1234yfR1234ze(E)

Figure 17 Cooling capacity versus refrigerant flow rate at Tc 35degC

1

2

3

4

5

6

0 05 1 15 2 25 3 35

COP

R134aR152a

R1234yfR1234ze(E)

V lowast 103 (m3s)

Figure 18 COP versus refrigerant volume flow rate

Advances in Materials Science and Engineering 11

condensing and evaporating temperatures e total exergyefficiency was decreased with the condensing temperaturewhile it was increased with the evaporating temperature For

both condensing and evaporating temperatures the re-frigerant R1234yf has the lowest exergy efficiency followedby R152a e highest exergy efficiency was obtained withR1234ze(E) at different condensing temperatures while atdifferent evaporating temperatures the highest exergy effi-ciency was obtained for R134a From the environmentalthermal and exergy point of view the refrigerant R1234yfhas the best performance among all refrigerants that havebeen investigated to replace R134a in an automotive air-conditioning system

7 Conclusion

Energy and exergy analysis was presented for many envi-ronmentally friendly refrigerants as a drop-in replacementof current high-GWP of R134a in the automotive air-con-ditioning system ree alternative refrigerants which isdistinguished by zero ODP and GWP100lt 150 were inves-tigated with particular reference to the current R134a re-frigerant (GWP100 1430) e exergy destruction of eachcomponent and the exergy efficiency at different condensingtemperatures evaporating temperatures and refrigerantflow rates were presented and the main conclusions aresummarized as follows

(i) For all values of condensing and evaporatingtemperatures a higher system COP was obtained at

01

02

03

04

05

06

07

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degC V = 00031m3s

η tot

al

Figure 20 Total exergy efficiency versus condensing temperature

0

01

02

03

04

05

06

15 20 25 30 35 40 45 50Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degC V = 00031m3s

η tot

al

Figure 21 Total exergy efficiency versus evaporating temperature

R134a R152a R1234yf R1234ze

030

025

020

015

010

005

000

CompressorCondenser

ExpansionEvaporator

Figure 19 Total exergy destruction of each component for dif-ferent refrigerant types

12 Advances in Materials Science and Engineering

a lower compressor speed which was producedfrom slow crankshaft RPM

(ii) A reduction in the cooling capacity by 9 and inCOP by 27 was confirmed when a condensingtemperature increased by 5degC

(iii) Based on the test results the refrigerant R1234ze(E)had the highest coefficient of performance amongall investigated refrigerants

(iv) e refrigerant R1234yf was considered the closestin thermal performance to the refrigerant R134a

(v) e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the totalexergy destruction of R1234yf and R152a was lowerthan that of R134a by 15 and 45 respectively

(vi) e refrigerant R1234ze(E) was the most envi-ronmentally acceptable and had the best energeticand exergetic performance among all the testedrefrigerants

(vii) e highest exergy efficiency was obtained forR1234ze(E) at different condensing temperatureswhile at different evaporating temperatures thehighest exergy efficiency was obtained for R134a

Nomenclature

COP coefficient of performanceCP specific heat kJkgmiddotKEmiddot

x exergy kWh specific enthalpy kJkg_mref refrigerant flow rate kgsp refrigerant pressure kPaQ rate of heat transfer kWRPM revolution per minute minminus 1

s entropy kJkgmiddotKT temperature K_V refrigerant flow rate m3sVCC volumetric cooling capacity kJm3

W compressor power kWGWP100 global warming potential for 100 yearsΡ density kgm3

c coolingcomp compressorcond condenserexp expansionevap evaporatordest destructiondis dischargein inletis isentropicmech mechanicalo dead stateout outlet

Data Availability

e data that support the findings of this study are availableupon request from the corresponding author

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e authors would like to express their sincere gratitude tothe Public Authority for Applied Education and Training(PAAET) Kuwait for supporting and funding this workResearch Project No TS -16-12 Research Project TitleldquoEnergetic and exergetic analysis of R1234yf R1234ze andR152 as a low-GWP alternatives of R134a in automotive airconditioningrdquo Special appreciation to Refrigeration and AirConditioning Department Faculty of Industrial EducationHelwan University Egypt for the technical assistance ex-tended to the authors

References

[1] I P Koronaki D Cowan G Maidment et al ldquoRefrigerantemissions and leakage prevention across Europemdashresultsfrom the real skills Europe projectrdquo Energy vol 45 no 1pp 71ndash80 2012

[2] Environmental Protection Agency Protection of StratosphericOzone Change of Listing Status for Certain Substitutes underthe Significant New Alternatives Policy Program Rules andRegulations Environmental Protection Agency EPAWashington DC USA 2015

[3] I Dincer and A R Marc Exergy Energy Environment andSustainable Development Elsevier Amsterdam NetherlandsSecond edition 2016

[4] H Cho and C Park ldquoExperimental investigation of perfor-mance and exergy analysis of automotive air conditioningsystems using refrigerant R1234yf at various compressorspeedsrdquo Applied 4ermal Engineering vol 101 pp 30ndash372016

[5] B Jemaa R Mansouri I Boukholda and A Bellagi ldquoEnergyand exergy investigation of R1234ze(E) as R134a replacementin vapor compression chillersrdquo International Journal of Hy-drogen Energy vol 42 no 17 pp 12877ndash12887 2017

[6] K Zhang Y Zhu J Liu X Niu and X Yuan ldquoExergy andenergy analysis of a double evaporating temperature chillerrdquoEnergy and Buildings vol 165 pp 464ndash471 2018

[7] J K Verma A Satsangi and V Chaturani ldquoA review ofalternative to R134a (CH3CH2F) refrigerantrdquo InternationalJournal of Emerging Technology and Advanced Engineeringvol 3 no 1 pp 300ndash304 2013

[8] J Garcia T Ali W M Duarte A Khosravi and L MachadoldquoComparison of transient response of an evaporatormodel forwater refrigeration system working with R1234yf as a drop-inreplacement for R134ardquo International Journal of Refrigera-tion vol 91 pp 211ndash222 2018

[9] E Navarro I O Martınez-Galvan J Nohales andJ Gonzalvez-Macia ldquoComparative experimental study of anopen piston compressor working with R-1234yf R-134a andR-290rdquo International Journal of Refrigeration vol 36 no 3pp 768ndash775 2013

[10] J Navarro-Esbrı J M Mendoza-Miranda A Mota-BabiloniA Barraga-Cervera A Barragan-Cervera and J M Belman-Flores ldquoExperimental analysis of R1234yf as a drop-in re-placement for R134a in a vapor compression systemrdquo In-ternational Journal of Refrigeration vol 36 no 3pp 870ndash880 2013

Advances in Materials Science and Engineering 13

[11] A Gomaa ldquoPerformance characteristics of automotive airconditioning system with refrigerant R134a and its alterna-tivesrdquo International Journal of Energy and Power Engineeringvol 4 no 3 pp 168ndash177 2015

[12] Y Lee and D Jung ldquoA brief performance comparison ofR1234yf and R134a in a bench tester for automobile appli-cationsrdquo Applied 4ermal Engineering vol 35 pp 240ndash2422012

[13] J M Belman-Flores V H Rangel-Hernandez S Uson andC Rubio-Maya ldquoEnergy and exergy analysis of R1234yf asdrop-in replacement for R134a in a domestic refrigerationsystemrdquo Energy vol 132 pp 116ndash125 2017

[14] M Joybari M H Hatamipour A Rahimi and F ModarresldquoExergy analysis and optimization of R600a as a replacementof R134a in a domestic refrigerator systemrdquo InternationalJournal of Refrigeration vol 36 no 4 pp 1233ndash1242 2013

[15] D Sanchez R Cabello R Llopis I Arauzo J Catalan-Giland E Torrella ldquoEnergy performance evaluation of R1234yfR1234ze(E) R600a R290 and R152a as low-GWP R134aalternativesrdquo International Journal of Refrigeration vol 74pp 269ndash282 2017

[16] S V Shaik and T P Ashok Babu ldquoeoretical computation ofperformance of sustainable energy efficient R22 alternativesfor residential air conditionersrdquo Energy Procedia vol 138pp 710ndash716 2017

[17] Z Li H Jiang X Chen and K Liang ldquoComparative study onenergy efficiency of low GWP refrigerants in domestic re-frigerators with capacity modulationrdquo Energy and Buildingsvol 192 pp 93ndash100 2019

[18] S S Vali T P Setty and A Babu ldquoAnalytical computation ofthermodynamic performance parameters of actual vapourcompression refrigeration system with R22 R32 R134aR152a R290 and R1270rdquo MATEC Web of Conferencesvol 144 Article ID 04009 2018

[19] G Relue and S Kopchick New Refrigerants Designation andSafety Classifications E360 Forum Emerson Raleigh NCUSA 2017

[20] ASHRAE Standard 34Designation and Safety Classification ofRefrigerants American Society of Heating Ventilating andAir-Conditioning Engineers Atlanta GA USA 2010

[21] J P Holman Experimental Method for Engineerspp 62ndash65McGraw-Hill Book Company New York NY USA Eighthedition 2001

[22] B O Bolaji ldquoExperimental study of R152a and R32 to replaceR134a in a domestic refrigeratorrdquo Energy vol 35 no 9pp 3793ndash3798 2010

[23] M Fatouh A I Eid and N Nabil ldquoPerformance of water-to-water vapor compression refrigeration system using R22 al-ternatives part I system simulationrdquo Engineering ResearchJournal vol 124 pp M19ndashM43 2009

[24] A Yataganbaba A Kilicarslan and I Kurtbas ldquoExergyanalysis of R1234yf and R1234ze as R134a replacements in atwo evaporator vapour compression refrigeration systemrdquoInternational Journal of Refrigeration vol 60 pp 26ndash37 2015

[25] G F Nellis and S A Klein Engineering Equation Solver (EES)F-Chart Software Wiley Middleton WI USA 2013

[26] R Llopis E Torrella R Cabello and D Sanchez ldquoPerfor-mance evaluation of R404A and R507A refrigerant mixturesin an experimental double-stage vapour compression plantrdquoApplied Energy vol 87 no 5 pp 1546ndash1553 2010

14 Advances in Materials Science and Engineering

Equation (2) is led to an increase in mass flow rate beinggreater than the decrease in the enthalpy difference (h2 minus h1)and consequently the compressor power consumption in-creases with evaporating temperature is trend curveconfirmed with Li et al [17] and Llopis et al [26]

e compressor power of R134a and R1234yf was quitesimilar A reduction in a compressor power for R152a andR1234ze(E) by 8 and 26 respectively was occurred whencompared with R134a

ere are two important parameters that can charac-terize the most appropriate alternative refrigerants toR134a volumetric cooling capacity and discharge tem-perature Figure 13 illustrates the volumetric refrigerationcapacity (VCC) and the discharge temperature versus theevaporating temperature for all investigated refrigerantse volumetric refrigeration capacity expresses the coolingcapacity per unit volume at the exit of the evaporator Itindicates the volume of refrigerants handled by the com-pressor It was noted that R134a has the highest volumetriccooling capacity followed by R152a and R1234yf while theR1234ze(E) has lowest values of volumetric cooling ca-pacity is mean that the refrigerants R152a and R1234yfcan be replaced by R134a on the same compressor size inwhich the refrigerant R1234ze(E) needs to resize thecompressor for a given duty

It is necessary to study the discharge temperature for thelow-GWP refrigerant compared with R134a in order toclarify the steadiness and lifetime of the compressor

Referring to Figure 13 which illustrates the dischargetemperature versus the evaporating temperature for all in-vestigated refrigerants it was noted that the refrigerantR152a has the highest discharge temperature and it isimpediment in replacement between R152a and R134awhile the discharge temperature of R1234ze(E) and R1234yfis lower than that of R134a which is considered an advantagein replacement between R1234ze(E) R1234yf and R134a

e changing of the evaporating temperature affects theCOP of the system positively which is illustrated in Figure 14As the evaporating temperature increased the COP of therefrigeration system increased which can be attributed to theincrease in cooling capacity and was more rapid than theincrease in compressor powere refrigerant R1234ze(E) hasthe highest values of the COP among all the investigatedrefrigerants It was confirmed that the thermal performance ofthe R1234yf refrigerant (GWP100 358 times less than that ofR134a) was the closest to the thermal performance of theR134a system and therefore a more environmentally sus-tainable refrigerant for automotive air conditioning

e exergy destruction for the system compressor withdifferent evaporating temperatures is illustrated in Figure 15e highest exergy destruction through the compressor wasobtained for R1234ze(E) followed by R134a while R152a hasthe lowest values of exergy destruction Compared with thebase refrigerant of R134a the compressor exergy destructionof the refrigerant R1234ze(E) was higher by 65 while thecompressor exergy destruction of R1234yf and R152a wasreduced by 11 and 40 respectively e total exergy

0

02

04

06

08

1

12

E tot

al (k

W)

15 20 25 30 35 40 45 50Tc (degC)

Te = 10degCV = 00031m3s

R134aR152a

R1234yfR1234ze(E)

Figure 11 Total exergy destruction versus condensing temperature

005

01

015

02

025

03

035

04

15 20 25 30 35 40 45 50

E com

p (k

W)

Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degCV = 00031m3s

Figure 10 Exergy destruction in compressor versus condensingtemperature

8 Advances in Materials Science and Engineering

destruction of the all-cycle components for different types ofrefrigerants and the evaporating temperature is illustrated inFigure 16 e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the total exergydestruction of R1234yf and R152a was lower than that ofR134a by 15 and 45 respectively

623 4e Effect of Refrigerant Flow Rate e refrigerantvolume flow rate variation which was produced as a result ofvarying compressor speed which in turn was originated fromautomotive crankshaft speed affects the performance of theautomotive air conditioninge effect of varying volume flowrate on the cooling capacity and the coefficient of performanceis illustrated in Figures 17 and 18 for a typical condition ofTe 10degC and Tc 35degC e refrigerant mass flow rate variedas the RPM of the crankshaft was changed which depend on

Table 3 Results of the investigated refrigerants at different condensing temperatures

Item Tc oC R152a R1234yf R1234ze(E) R134a

Cooling capacity

30 660 669 561 69035 644 638 538 66540 624 606 515 63945 604 573 491 612

Compressor power

30 158 169 125 17135 1774 190 143 19440 1984 211 160 21545 2191 231 177 237

COP

30 418 396 447 40335 363 336 377 34440 315 288 322 29745 276 248 278 258

Total exergy destruction Etotal

30 0549 0851 0845 074835 0530 0812 0821 073040 0524 0780 0801 071045 0532 0770 0797 0701

Total exergy efficiency ηtotal

30 0322 028 0357 03435 0299 026 0336 03240 027 025 031 0345 0255 024 029 028

0

05

1

15

2

25

3

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Pow

er (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 12 Compressor power versus evaporating temperature

Disc

harg

e tem

pera

ture

(degC)

0

20

40

60

80

100

120

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Vol

umet

ric co

olin

g ca

paci

ty (k

Jm3 )

Te (degC)

VCC R134aVCC R152VCC R1234yfVCC R1234ze

Tdis R134aTdis R152aTdis R1234yfTdis R1234ze(E)

Figure 13 Effect of evaporating temperature on volumetriccooling capacity and discharge temperature

Advances in Materials Science and Engineering 9

the rate of fuel consumption of the automotive engine Inpractice the refrigerant mass flow rate ( _m ρ _v) which is therefrigerant density multiplied by volume flow rate affects thecooling capacity and compressor power according to equa-tions (1) and (2) in which the density varies according tovariation in evaporating temperature erefore the influenceof the refrigerant flow rate was evident to the coefficient ofperformance As the refrigerant flow rate increases the COPdecreases which can be explained by the increase in com-pressor power with a flow rate greater than the increase incooling capacity It is noted that the refrigerant R1234ze(E) hasthe highest COP between investigated refrigerants

e total exergy destruction of the compressor con-denser expansion valve and evaporator for the differentrefrigerant types is illustrated in Figure 19 e highestexergy destruction of the compressor was obtained forR1234ze(E) and the highest exergy destruction of thecondenser was obtained for R1234fy while the lowest valueof exergy destruction for the compressor and condenser wasobtained for R152a e highest values of the exergy de-struction for the evaporator and expansion valve were ob-tained for R1234ze(E) and R1234fy respectively

Exergy efficiency can give more logical ways to improvethe energy performance of automotive air conditioning Forthat reason the exergy analysis which was performed foreach cycle component should be considered integrated [6]Figures 20 and 21 show the total exergy efficiency with both

1

2

3

4

5

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

COP

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 14 COP versus evaporating temperature for Tc 35degC

005

01

015

02

025

03

035

04

ndash15 ndash10 ndash5 0 5 10 15 20

E com

p (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 15 Exergy destruction in compressor versus evaporatingtemperature

0

01

02

03

04

05

06

07

08

09

1

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

E tot

al

Figure 16 Total exergy destruction versus evaporatingtemperature

10 Advances in Materials Science and Engineering

0

1

2

3

4

5

6

7

8

0 05 1 15 2 25 3 35

Cool

ing

capa

city

(kW

)

V lowast 103 (m3s)

R134aR152a

R1234yfR1234ze(E)

Figure 17 Cooling capacity versus refrigerant flow rate at Tc 35degC

1

2

3

4

5

6

0 05 1 15 2 25 3 35

COP

R134aR152a

R1234yfR1234ze(E)

V lowast 103 (m3s)

Figure 18 COP versus refrigerant volume flow rate

Advances in Materials Science and Engineering 11

condensing and evaporating temperatures e total exergyefficiency was decreased with the condensing temperaturewhile it was increased with the evaporating temperature For

both condensing and evaporating temperatures the re-frigerant R1234yf has the lowest exergy efficiency followedby R152a e highest exergy efficiency was obtained withR1234ze(E) at different condensing temperatures while atdifferent evaporating temperatures the highest exergy effi-ciency was obtained for R134a From the environmentalthermal and exergy point of view the refrigerant R1234yfhas the best performance among all refrigerants that havebeen investigated to replace R134a in an automotive air-conditioning system

7 Conclusion

Energy and exergy analysis was presented for many envi-ronmentally friendly refrigerants as a drop-in replacementof current high-GWP of R134a in the automotive air-con-ditioning system ree alternative refrigerants which isdistinguished by zero ODP and GWP100lt 150 were inves-tigated with particular reference to the current R134a re-frigerant (GWP100 1430) e exergy destruction of eachcomponent and the exergy efficiency at different condensingtemperatures evaporating temperatures and refrigerantflow rates were presented and the main conclusions aresummarized as follows

(i) For all values of condensing and evaporatingtemperatures a higher system COP was obtained at

01

02

03

04

05

06

07

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degC V = 00031m3s

η tot

al

Figure 20 Total exergy efficiency versus condensing temperature

0

01

02

03

04

05

06

15 20 25 30 35 40 45 50Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degC V = 00031m3s

η tot

al

Figure 21 Total exergy efficiency versus evaporating temperature

R134a R152a R1234yf R1234ze

030

025

020

015

010

005

000

CompressorCondenser

ExpansionEvaporator

Figure 19 Total exergy destruction of each component for dif-ferent refrigerant types

12 Advances in Materials Science and Engineering

a lower compressor speed which was producedfrom slow crankshaft RPM

(ii) A reduction in the cooling capacity by 9 and inCOP by 27 was confirmed when a condensingtemperature increased by 5degC

(iii) Based on the test results the refrigerant R1234ze(E)had the highest coefficient of performance amongall investigated refrigerants

(iv) e refrigerant R1234yf was considered the closestin thermal performance to the refrigerant R134a

(v) e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the totalexergy destruction of R1234yf and R152a was lowerthan that of R134a by 15 and 45 respectively

(vi) e refrigerant R1234ze(E) was the most envi-ronmentally acceptable and had the best energeticand exergetic performance among all the testedrefrigerants

(vii) e highest exergy efficiency was obtained forR1234ze(E) at different condensing temperatureswhile at different evaporating temperatures thehighest exergy efficiency was obtained for R134a

Nomenclature

COP coefficient of performanceCP specific heat kJkgmiddotKEmiddot

x exergy kWh specific enthalpy kJkg_mref refrigerant flow rate kgsp refrigerant pressure kPaQ rate of heat transfer kWRPM revolution per minute minminus 1

s entropy kJkgmiddotKT temperature K_V refrigerant flow rate m3sVCC volumetric cooling capacity kJm3

W compressor power kWGWP100 global warming potential for 100 yearsΡ density kgm3

c coolingcomp compressorcond condenserexp expansionevap evaporatordest destructiondis dischargein inletis isentropicmech mechanicalo dead stateout outlet

Data Availability

e data that support the findings of this study are availableupon request from the corresponding author

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e authors would like to express their sincere gratitude tothe Public Authority for Applied Education and Training(PAAET) Kuwait for supporting and funding this workResearch Project No TS -16-12 Research Project TitleldquoEnergetic and exergetic analysis of R1234yf R1234ze andR152 as a low-GWP alternatives of R134a in automotive airconditioningrdquo Special appreciation to Refrigeration and AirConditioning Department Faculty of Industrial EducationHelwan University Egypt for the technical assistance ex-tended to the authors

References

[1] I P Koronaki D Cowan G Maidment et al ldquoRefrigerantemissions and leakage prevention across Europemdashresultsfrom the real skills Europe projectrdquo Energy vol 45 no 1pp 71ndash80 2012

[2] Environmental Protection Agency Protection of StratosphericOzone Change of Listing Status for Certain Substitutes underthe Significant New Alternatives Policy Program Rules andRegulations Environmental Protection Agency EPAWashington DC USA 2015

[3] I Dincer and A R Marc Exergy Energy Environment andSustainable Development Elsevier Amsterdam NetherlandsSecond edition 2016

[4] H Cho and C Park ldquoExperimental investigation of perfor-mance and exergy analysis of automotive air conditioningsystems using refrigerant R1234yf at various compressorspeedsrdquo Applied 4ermal Engineering vol 101 pp 30ndash372016

[5] B Jemaa R Mansouri I Boukholda and A Bellagi ldquoEnergyand exergy investigation of R1234ze(E) as R134a replacementin vapor compression chillersrdquo International Journal of Hy-drogen Energy vol 42 no 17 pp 12877ndash12887 2017

[6] K Zhang Y Zhu J Liu X Niu and X Yuan ldquoExergy andenergy analysis of a double evaporating temperature chillerrdquoEnergy and Buildings vol 165 pp 464ndash471 2018

[7] J K Verma A Satsangi and V Chaturani ldquoA review ofalternative to R134a (CH3CH2F) refrigerantrdquo InternationalJournal of Emerging Technology and Advanced Engineeringvol 3 no 1 pp 300ndash304 2013

[8] J Garcia T Ali W M Duarte A Khosravi and L MachadoldquoComparison of transient response of an evaporatormodel forwater refrigeration system working with R1234yf as a drop-inreplacement for R134ardquo International Journal of Refrigera-tion vol 91 pp 211ndash222 2018

[9] E Navarro I O Martınez-Galvan J Nohales andJ Gonzalvez-Macia ldquoComparative experimental study of anopen piston compressor working with R-1234yf R-134a andR-290rdquo International Journal of Refrigeration vol 36 no 3pp 768ndash775 2013

[10] J Navarro-Esbrı J M Mendoza-Miranda A Mota-BabiloniA Barraga-Cervera A Barragan-Cervera and J M Belman-Flores ldquoExperimental analysis of R1234yf as a drop-in re-placement for R134a in a vapor compression systemrdquo In-ternational Journal of Refrigeration vol 36 no 3pp 870ndash880 2013

Advances in Materials Science and Engineering 13

[11] A Gomaa ldquoPerformance characteristics of automotive airconditioning system with refrigerant R134a and its alterna-tivesrdquo International Journal of Energy and Power Engineeringvol 4 no 3 pp 168ndash177 2015

[12] Y Lee and D Jung ldquoA brief performance comparison ofR1234yf and R134a in a bench tester for automobile appli-cationsrdquo Applied 4ermal Engineering vol 35 pp 240ndash2422012

[13] J M Belman-Flores V H Rangel-Hernandez S Uson andC Rubio-Maya ldquoEnergy and exergy analysis of R1234yf asdrop-in replacement for R134a in a domestic refrigerationsystemrdquo Energy vol 132 pp 116ndash125 2017

[14] M Joybari M H Hatamipour A Rahimi and F ModarresldquoExergy analysis and optimization of R600a as a replacementof R134a in a domestic refrigerator systemrdquo InternationalJournal of Refrigeration vol 36 no 4 pp 1233ndash1242 2013

[15] D Sanchez R Cabello R Llopis I Arauzo J Catalan-Giland E Torrella ldquoEnergy performance evaluation of R1234yfR1234ze(E) R600a R290 and R152a as low-GWP R134aalternativesrdquo International Journal of Refrigeration vol 74pp 269ndash282 2017

[16] S V Shaik and T P Ashok Babu ldquoeoretical computation ofperformance of sustainable energy efficient R22 alternativesfor residential air conditionersrdquo Energy Procedia vol 138pp 710ndash716 2017

[17] Z Li H Jiang X Chen and K Liang ldquoComparative study onenergy efficiency of low GWP refrigerants in domestic re-frigerators with capacity modulationrdquo Energy and Buildingsvol 192 pp 93ndash100 2019

[18] S S Vali T P Setty and A Babu ldquoAnalytical computation ofthermodynamic performance parameters of actual vapourcompression refrigeration system with R22 R32 R134aR152a R290 and R1270rdquo MATEC Web of Conferencesvol 144 Article ID 04009 2018

[19] G Relue and S Kopchick New Refrigerants Designation andSafety Classifications E360 Forum Emerson Raleigh NCUSA 2017

[20] ASHRAE Standard 34Designation and Safety Classification ofRefrigerants American Society of Heating Ventilating andAir-Conditioning Engineers Atlanta GA USA 2010

[21] J P Holman Experimental Method for Engineerspp 62ndash65McGraw-Hill Book Company New York NY USA Eighthedition 2001

[22] B O Bolaji ldquoExperimental study of R152a and R32 to replaceR134a in a domestic refrigeratorrdquo Energy vol 35 no 9pp 3793ndash3798 2010

[23] M Fatouh A I Eid and N Nabil ldquoPerformance of water-to-water vapor compression refrigeration system using R22 al-ternatives part I system simulationrdquo Engineering ResearchJournal vol 124 pp M19ndashM43 2009

[24] A Yataganbaba A Kilicarslan and I Kurtbas ldquoExergyanalysis of R1234yf and R1234ze as R134a replacements in atwo evaporator vapour compression refrigeration systemrdquoInternational Journal of Refrigeration vol 60 pp 26ndash37 2015

[25] G F Nellis and S A Klein Engineering Equation Solver (EES)F-Chart Software Wiley Middleton WI USA 2013

[26] R Llopis E Torrella R Cabello and D Sanchez ldquoPerfor-mance evaluation of R404A and R507A refrigerant mixturesin an experimental double-stage vapour compression plantrdquoApplied Energy vol 87 no 5 pp 1546ndash1553 2010

14 Advances in Materials Science and Engineering

destruction of the all-cycle components for different types ofrefrigerants and the evaporating temperature is illustrated inFigure 16 e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the total exergydestruction of R1234yf and R152a was lower than that ofR134a by 15 and 45 respectively

623 4e Effect of Refrigerant Flow Rate e refrigerantvolume flow rate variation which was produced as a result ofvarying compressor speed which in turn was originated fromautomotive crankshaft speed affects the performance of theautomotive air conditioninge effect of varying volume flowrate on the cooling capacity and the coefficient of performanceis illustrated in Figures 17 and 18 for a typical condition ofTe 10degC and Tc 35degC e refrigerant mass flow rate variedas the RPM of the crankshaft was changed which depend on

Table 3 Results of the investigated refrigerants at different condensing temperatures

Item Tc oC R152a R1234yf R1234ze(E) R134a

Cooling capacity

30 660 669 561 69035 644 638 538 66540 624 606 515 63945 604 573 491 612

Compressor power

30 158 169 125 17135 1774 190 143 19440 1984 211 160 21545 2191 231 177 237

COP

30 418 396 447 40335 363 336 377 34440 315 288 322 29745 276 248 278 258

Total exergy destruction Etotal

30 0549 0851 0845 074835 0530 0812 0821 073040 0524 0780 0801 071045 0532 0770 0797 0701

Total exergy efficiency ηtotal

30 0322 028 0357 03435 0299 026 0336 03240 027 025 031 0345 0255 024 029 028

0

05

1

15

2

25

3

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Pow

er (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Figure 12 Compressor power versus evaporating temperature

Disc

harg

e tem

pera

ture

(degC)

0

20

40

60

80

100

120

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

Vol

umet

ric co

olin

g ca

paci

ty (k

Jm3 )

Te (degC)

VCC R134aVCC R152VCC R1234yfVCC R1234ze

Tdis R134aTdis R152aTdis R1234yfTdis R1234ze(E)

Figure 13 Effect of evaporating temperature on volumetriccooling capacity and discharge temperature

Advances in Materials Science and Engineering 9

the rate of fuel consumption of the automotive engine Inpractice the refrigerant mass flow rate ( _m ρ _v) which is therefrigerant density multiplied by volume flow rate affects thecooling capacity and compressor power according to equa-tions (1) and (2) in which the density varies according tovariation in evaporating temperature erefore the influenceof the refrigerant flow rate was evident to the coefficient ofperformance As the refrigerant flow rate increases the COPdecreases which can be explained by the increase in com-pressor power with a flow rate greater than the increase incooling capacity It is noted that the refrigerant R1234ze(E) hasthe highest COP between investigated refrigerants

e total exergy destruction of the compressor con-denser expansion valve and evaporator for the differentrefrigerant types is illustrated in Figure 19 e highestexergy destruction of the compressor was obtained forR1234ze(E) and the highest exergy destruction of thecondenser was obtained for R1234fy while the lowest valueof exergy destruction for the compressor and condenser wasobtained for R152a e highest values of the exergy de-struction for the evaporator and expansion valve were ob-tained for R1234ze(E) and R1234fy respectively

Exergy efficiency can give more logical ways to improvethe energy performance of automotive air conditioning Forthat reason the exergy analysis which was performed foreach cycle component should be considered integrated [6]Figures 20 and 21 show the total exergy efficiency with both

1

2

3

4

5

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

COP

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 14 COP versus evaporating temperature for Tc 35degC

005

01

015

02

025

03

035

04

ndash15 ndash10 ndash5 0 5 10 15 20

E com

p (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 15 Exergy destruction in compressor versus evaporatingtemperature

0

01

02

03

04

05

06

07

08

09

1

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

E tot

al

Figure 16 Total exergy destruction versus evaporatingtemperature

10 Advances in Materials Science and Engineering

0

1

2

3

4

5

6

7

8

0 05 1 15 2 25 3 35

Cool

ing

capa

city

(kW

)

V lowast 103 (m3s)

R134aR152a

R1234yfR1234ze(E)

Figure 17 Cooling capacity versus refrigerant flow rate at Tc 35degC

1

2

3

4

5

6

0 05 1 15 2 25 3 35

COP

R134aR152a

R1234yfR1234ze(E)

V lowast 103 (m3s)

Figure 18 COP versus refrigerant volume flow rate

Advances in Materials Science and Engineering 11

condensing and evaporating temperatures e total exergyefficiency was decreased with the condensing temperaturewhile it was increased with the evaporating temperature For

both condensing and evaporating temperatures the re-frigerant R1234yf has the lowest exergy efficiency followedby R152a e highest exergy efficiency was obtained withR1234ze(E) at different condensing temperatures while atdifferent evaporating temperatures the highest exergy effi-ciency was obtained for R134a From the environmentalthermal and exergy point of view the refrigerant R1234yfhas the best performance among all refrigerants that havebeen investigated to replace R134a in an automotive air-conditioning system

7 Conclusion

Energy and exergy analysis was presented for many envi-ronmentally friendly refrigerants as a drop-in replacementof current high-GWP of R134a in the automotive air-con-ditioning system ree alternative refrigerants which isdistinguished by zero ODP and GWP100lt 150 were inves-tigated with particular reference to the current R134a re-frigerant (GWP100 1430) e exergy destruction of eachcomponent and the exergy efficiency at different condensingtemperatures evaporating temperatures and refrigerantflow rates were presented and the main conclusions aresummarized as follows

(i) For all values of condensing and evaporatingtemperatures a higher system COP was obtained at

01

02

03

04

05

06

07

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degC V = 00031m3s

η tot

al

Figure 20 Total exergy efficiency versus condensing temperature

0

01

02

03

04

05

06

15 20 25 30 35 40 45 50Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degC V = 00031m3s

η tot

al

Figure 21 Total exergy efficiency versus evaporating temperature

R134a R152a R1234yf R1234ze

030

025

020

015

010

005

000

CompressorCondenser

ExpansionEvaporator

Figure 19 Total exergy destruction of each component for dif-ferent refrigerant types

12 Advances in Materials Science and Engineering

a lower compressor speed which was producedfrom slow crankshaft RPM

(ii) A reduction in the cooling capacity by 9 and inCOP by 27 was confirmed when a condensingtemperature increased by 5degC

(iii) Based on the test results the refrigerant R1234ze(E)had the highest coefficient of performance amongall investigated refrigerants

(iv) e refrigerant R1234yf was considered the closestin thermal performance to the refrigerant R134a

(v) e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the totalexergy destruction of R1234yf and R152a was lowerthan that of R134a by 15 and 45 respectively

(vi) e refrigerant R1234ze(E) was the most envi-ronmentally acceptable and had the best energeticand exergetic performance among all the testedrefrigerants

(vii) e highest exergy efficiency was obtained forR1234ze(E) at different condensing temperatureswhile at different evaporating temperatures thehighest exergy efficiency was obtained for R134a

Nomenclature

COP coefficient of performanceCP specific heat kJkgmiddotKEmiddot

x exergy kWh specific enthalpy kJkg_mref refrigerant flow rate kgsp refrigerant pressure kPaQ rate of heat transfer kWRPM revolution per minute minminus 1

s entropy kJkgmiddotKT temperature K_V refrigerant flow rate m3sVCC volumetric cooling capacity kJm3

W compressor power kWGWP100 global warming potential for 100 yearsΡ density kgm3

c coolingcomp compressorcond condenserexp expansionevap evaporatordest destructiondis dischargein inletis isentropicmech mechanicalo dead stateout outlet

Data Availability

e data that support the findings of this study are availableupon request from the corresponding author

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e authors would like to express their sincere gratitude tothe Public Authority for Applied Education and Training(PAAET) Kuwait for supporting and funding this workResearch Project No TS -16-12 Research Project TitleldquoEnergetic and exergetic analysis of R1234yf R1234ze andR152 as a low-GWP alternatives of R134a in automotive airconditioningrdquo Special appreciation to Refrigeration and AirConditioning Department Faculty of Industrial EducationHelwan University Egypt for the technical assistance ex-tended to the authors

References

[1] I P Koronaki D Cowan G Maidment et al ldquoRefrigerantemissions and leakage prevention across Europemdashresultsfrom the real skills Europe projectrdquo Energy vol 45 no 1pp 71ndash80 2012

[2] Environmental Protection Agency Protection of StratosphericOzone Change of Listing Status for Certain Substitutes underthe Significant New Alternatives Policy Program Rules andRegulations Environmental Protection Agency EPAWashington DC USA 2015

[3] I Dincer and A R Marc Exergy Energy Environment andSustainable Development Elsevier Amsterdam NetherlandsSecond edition 2016

[4] H Cho and C Park ldquoExperimental investigation of perfor-mance and exergy analysis of automotive air conditioningsystems using refrigerant R1234yf at various compressorspeedsrdquo Applied 4ermal Engineering vol 101 pp 30ndash372016

[5] B Jemaa R Mansouri I Boukholda and A Bellagi ldquoEnergyand exergy investigation of R1234ze(E) as R134a replacementin vapor compression chillersrdquo International Journal of Hy-drogen Energy vol 42 no 17 pp 12877ndash12887 2017

[6] K Zhang Y Zhu J Liu X Niu and X Yuan ldquoExergy andenergy analysis of a double evaporating temperature chillerrdquoEnergy and Buildings vol 165 pp 464ndash471 2018

[7] J K Verma A Satsangi and V Chaturani ldquoA review ofalternative to R134a (CH3CH2F) refrigerantrdquo InternationalJournal of Emerging Technology and Advanced Engineeringvol 3 no 1 pp 300ndash304 2013

[8] J Garcia T Ali W M Duarte A Khosravi and L MachadoldquoComparison of transient response of an evaporatormodel forwater refrigeration system working with R1234yf as a drop-inreplacement for R134ardquo International Journal of Refrigera-tion vol 91 pp 211ndash222 2018

[9] E Navarro I O Martınez-Galvan J Nohales andJ Gonzalvez-Macia ldquoComparative experimental study of anopen piston compressor working with R-1234yf R-134a andR-290rdquo International Journal of Refrigeration vol 36 no 3pp 768ndash775 2013

[10] J Navarro-Esbrı J M Mendoza-Miranda A Mota-BabiloniA Barraga-Cervera A Barragan-Cervera and J M Belman-Flores ldquoExperimental analysis of R1234yf as a drop-in re-placement for R134a in a vapor compression systemrdquo In-ternational Journal of Refrigeration vol 36 no 3pp 870ndash880 2013

Advances in Materials Science and Engineering 13

[11] A Gomaa ldquoPerformance characteristics of automotive airconditioning system with refrigerant R134a and its alterna-tivesrdquo International Journal of Energy and Power Engineeringvol 4 no 3 pp 168ndash177 2015

[12] Y Lee and D Jung ldquoA brief performance comparison ofR1234yf and R134a in a bench tester for automobile appli-cationsrdquo Applied 4ermal Engineering vol 35 pp 240ndash2422012

[13] J M Belman-Flores V H Rangel-Hernandez S Uson andC Rubio-Maya ldquoEnergy and exergy analysis of R1234yf asdrop-in replacement for R134a in a domestic refrigerationsystemrdquo Energy vol 132 pp 116ndash125 2017

[14] M Joybari M H Hatamipour A Rahimi and F ModarresldquoExergy analysis and optimization of R600a as a replacementof R134a in a domestic refrigerator systemrdquo InternationalJournal of Refrigeration vol 36 no 4 pp 1233ndash1242 2013

[15] D Sanchez R Cabello R Llopis I Arauzo J Catalan-Giland E Torrella ldquoEnergy performance evaluation of R1234yfR1234ze(E) R600a R290 and R152a as low-GWP R134aalternativesrdquo International Journal of Refrigeration vol 74pp 269ndash282 2017

[16] S V Shaik and T P Ashok Babu ldquoeoretical computation ofperformance of sustainable energy efficient R22 alternativesfor residential air conditionersrdquo Energy Procedia vol 138pp 710ndash716 2017

[17] Z Li H Jiang X Chen and K Liang ldquoComparative study onenergy efficiency of low GWP refrigerants in domestic re-frigerators with capacity modulationrdquo Energy and Buildingsvol 192 pp 93ndash100 2019

[18] S S Vali T P Setty and A Babu ldquoAnalytical computation ofthermodynamic performance parameters of actual vapourcompression refrigeration system with R22 R32 R134aR152a R290 and R1270rdquo MATEC Web of Conferencesvol 144 Article ID 04009 2018

[19] G Relue and S Kopchick New Refrigerants Designation andSafety Classifications E360 Forum Emerson Raleigh NCUSA 2017

[20] ASHRAE Standard 34Designation and Safety Classification ofRefrigerants American Society of Heating Ventilating andAir-Conditioning Engineers Atlanta GA USA 2010

[21] J P Holman Experimental Method for Engineerspp 62ndash65McGraw-Hill Book Company New York NY USA Eighthedition 2001

[22] B O Bolaji ldquoExperimental study of R152a and R32 to replaceR134a in a domestic refrigeratorrdquo Energy vol 35 no 9pp 3793ndash3798 2010

[23] M Fatouh A I Eid and N Nabil ldquoPerformance of water-to-water vapor compression refrigeration system using R22 al-ternatives part I system simulationrdquo Engineering ResearchJournal vol 124 pp M19ndashM43 2009

[24] A Yataganbaba A Kilicarslan and I Kurtbas ldquoExergyanalysis of R1234yf and R1234ze as R134a replacements in atwo evaporator vapour compression refrigeration systemrdquoInternational Journal of Refrigeration vol 60 pp 26ndash37 2015

[25] G F Nellis and S A Klein Engineering Equation Solver (EES)F-Chart Software Wiley Middleton WI USA 2013

[26] R Llopis E Torrella R Cabello and D Sanchez ldquoPerfor-mance evaluation of R404A and R507A refrigerant mixturesin an experimental double-stage vapour compression plantrdquoApplied Energy vol 87 no 5 pp 1546ndash1553 2010

14 Advances in Materials Science and Engineering

the rate of fuel consumption of the automotive engine Inpractice the refrigerant mass flow rate ( _m ρ _v) which is therefrigerant density multiplied by volume flow rate affects thecooling capacity and compressor power according to equa-tions (1) and (2) in which the density varies according tovariation in evaporating temperature erefore the influenceof the refrigerant flow rate was evident to the coefficient ofperformance As the refrigerant flow rate increases the COPdecreases which can be explained by the increase in com-pressor power with a flow rate greater than the increase incooling capacity It is noted that the refrigerant R1234ze(E) hasthe highest COP between investigated refrigerants

e total exergy destruction of the compressor con-denser expansion valve and evaporator for the differentrefrigerant types is illustrated in Figure 19 e highestexergy destruction of the compressor was obtained forR1234ze(E) and the highest exergy destruction of thecondenser was obtained for R1234fy while the lowest valueof exergy destruction for the compressor and condenser wasobtained for R152a e highest values of the exergy de-struction for the evaporator and expansion valve were ob-tained for R1234ze(E) and R1234fy respectively

Exergy efficiency can give more logical ways to improvethe energy performance of automotive air conditioning Forthat reason the exergy analysis which was performed foreach cycle component should be considered integrated [6]Figures 20 and 21 show the total exergy efficiency with both

1

2

3

4

5

ndash20 ndash15 ndash10 ndash5 0 5 10 15 20

COP

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 14 COP versus evaporating temperature for Tc 35degC

005

01

015

02

025

03

035

04

ndash15 ndash10 ndash5 0 5 10 15 20

E com

p (k

W)

Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

Figure 15 Exergy destruction in compressor versus evaporatingtemperature

0

01

02

03

04

05

06

07

08

09

1

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degCV = 00031m3s

E tot

al

Figure 16 Total exergy destruction versus evaporatingtemperature

10 Advances in Materials Science and Engineering

0

1

2

3

4

5

6

7

8

0 05 1 15 2 25 3 35

Cool

ing

capa

city

(kW

)

V lowast 103 (m3s)

R134aR152a

R1234yfR1234ze(E)

Figure 17 Cooling capacity versus refrigerant flow rate at Tc 35degC

1

2

3

4

5

6

0 05 1 15 2 25 3 35

COP

R134aR152a

R1234yfR1234ze(E)

V lowast 103 (m3s)

Figure 18 COP versus refrigerant volume flow rate

Advances in Materials Science and Engineering 11

condensing and evaporating temperatures e total exergyefficiency was decreased with the condensing temperaturewhile it was increased with the evaporating temperature For

both condensing and evaporating temperatures the re-frigerant R1234yf has the lowest exergy efficiency followedby R152a e highest exergy efficiency was obtained withR1234ze(E) at different condensing temperatures while atdifferent evaporating temperatures the highest exergy effi-ciency was obtained for R134a From the environmentalthermal and exergy point of view the refrigerant R1234yfhas the best performance among all refrigerants that havebeen investigated to replace R134a in an automotive air-conditioning system

7 Conclusion

Energy and exergy analysis was presented for many envi-ronmentally friendly refrigerants as a drop-in replacementof current high-GWP of R134a in the automotive air-con-ditioning system ree alternative refrigerants which isdistinguished by zero ODP and GWP100lt 150 were inves-tigated with particular reference to the current R134a re-frigerant (GWP100 1430) e exergy destruction of eachcomponent and the exergy efficiency at different condensingtemperatures evaporating temperatures and refrigerantflow rates were presented and the main conclusions aresummarized as follows

(i) For all values of condensing and evaporatingtemperatures a higher system COP was obtained at

01

02

03

04

05

06

07

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degC V = 00031m3s

η tot

al

Figure 20 Total exergy efficiency versus condensing temperature

0

01

02

03

04

05

06

15 20 25 30 35 40 45 50Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degC V = 00031m3s

η tot

al

Figure 21 Total exergy efficiency versus evaporating temperature

R134a R152a R1234yf R1234ze

030

025

020

015

010

005

000

CompressorCondenser

ExpansionEvaporator

Figure 19 Total exergy destruction of each component for dif-ferent refrigerant types

12 Advances in Materials Science and Engineering

a lower compressor speed which was producedfrom slow crankshaft RPM

(ii) A reduction in the cooling capacity by 9 and inCOP by 27 was confirmed when a condensingtemperature increased by 5degC

(iii) Based on the test results the refrigerant R1234ze(E)had the highest coefficient of performance amongall investigated refrigerants

(iv) e refrigerant R1234yf was considered the closestin thermal performance to the refrigerant R134a

(v) e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the totalexergy destruction of R1234yf and R152a was lowerthan that of R134a by 15 and 45 respectively

(vi) e refrigerant R1234ze(E) was the most envi-ronmentally acceptable and had the best energeticand exergetic performance among all the testedrefrigerants

(vii) e highest exergy efficiency was obtained forR1234ze(E) at different condensing temperatureswhile at different evaporating temperatures thehighest exergy efficiency was obtained for R134a

Nomenclature

COP coefficient of performanceCP specific heat kJkgmiddotKEmiddot

x exergy kWh specific enthalpy kJkg_mref refrigerant flow rate kgsp refrigerant pressure kPaQ rate of heat transfer kWRPM revolution per minute minminus 1

s entropy kJkgmiddotKT temperature K_V refrigerant flow rate m3sVCC volumetric cooling capacity kJm3

W compressor power kWGWP100 global warming potential for 100 yearsΡ density kgm3

c coolingcomp compressorcond condenserexp expansionevap evaporatordest destructiondis dischargein inletis isentropicmech mechanicalo dead stateout outlet

Data Availability

e data that support the findings of this study are availableupon request from the corresponding author

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e authors would like to express their sincere gratitude tothe Public Authority for Applied Education and Training(PAAET) Kuwait for supporting and funding this workResearch Project No TS -16-12 Research Project TitleldquoEnergetic and exergetic analysis of R1234yf R1234ze andR152 as a low-GWP alternatives of R134a in automotive airconditioningrdquo Special appreciation to Refrigeration and AirConditioning Department Faculty of Industrial EducationHelwan University Egypt for the technical assistance ex-tended to the authors

References

[1] I P Koronaki D Cowan G Maidment et al ldquoRefrigerantemissions and leakage prevention across Europemdashresultsfrom the real skills Europe projectrdquo Energy vol 45 no 1pp 71ndash80 2012

[2] Environmental Protection Agency Protection of StratosphericOzone Change of Listing Status for Certain Substitutes underthe Significant New Alternatives Policy Program Rules andRegulations Environmental Protection Agency EPAWashington DC USA 2015

[3] I Dincer and A R Marc Exergy Energy Environment andSustainable Development Elsevier Amsterdam NetherlandsSecond edition 2016

[4] H Cho and C Park ldquoExperimental investigation of perfor-mance and exergy analysis of automotive air conditioningsystems using refrigerant R1234yf at various compressorspeedsrdquo Applied 4ermal Engineering vol 101 pp 30ndash372016

[5] B Jemaa R Mansouri I Boukholda and A Bellagi ldquoEnergyand exergy investigation of R1234ze(E) as R134a replacementin vapor compression chillersrdquo International Journal of Hy-drogen Energy vol 42 no 17 pp 12877ndash12887 2017

[6] K Zhang Y Zhu J Liu X Niu and X Yuan ldquoExergy andenergy analysis of a double evaporating temperature chillerrdquoEnergy and Buildings vol 165 pp 464ndash471 2018

[7] J K Verma A Satsangi and V Chaturani ldquoA review ofalternative to R134a (CH3CH2F) refrigerantrdquo InternationalJournal of Emerging Technology and Advanced Engineeringvol 3 no 1 pp 300ndash304 2013

[8] J Garcia T Ali W M Duarte A Khosravi and L MachadoldquoComparison of transient response of an evaporatormodel forwater refrigeration system working with R1234yf as a drop-inreplacement for R134ardquo International Journal of Refrigera-tion vol 91 pp 211ndash222 2018

[9] E Navarro I O Martınez-Galvan J Nohales andJ Gonzalvez-Macia ldquoComparative experimental study of anopen piston compressor working with R-1234yf R-134a andR-290rdquo International Journal of Refrigeration vol 36 no 3pp 768ndash775 2013

[10] J Navarro-Esbrı J M Mendoza-Miranda A Mota-BabiloniA Barraga-Cervera A Barragan-Cervera and J M Belman-Flores ldquoExperimental analysis of R1234yf as a drop-in re-placement for R134a in a vapor compression systemrdquo In-ternational Journal of Refrigeration vol 36 no 3pp 870ndash880 2013

Advances in Materials Science and Engineering 13

[11] A Gomaa ldquoPerformance characteristics of automotive airconditioning system with refrigerant R134a and its alterna-tivesrdquo International Journal of Energy and Power Engineeringvol 4 no 3 pp 168ndash177 2015

[12] Y Lee and D Jung ldquoA brief performance comparison ofR1234yf and R134a in a bench tester for automobile appli-cationsrdquo Applied 4ermal Engineering vol 35 pp 240ndash2422012

[13] J M Belman-Flores V H Rangel-Hernandez S Uson andC Rubio-Maya ldquoEnergy and exergy analysis of R1234yf asdrop-in replacement for R134a in a domestic refrigerationsystemrdquo Energy vol 132 pp 116ndash125 2017

[14] M Joybari M H Hatamipour A Rahimi and F ModarresldquoExergy analysis and optimization of R600a as a replacementof R134a in a domestic refrigerator systemrdquo InternationalJournal of Refrigeration vol 36 no 4 pp 1233ndash1242 2013

[15] D Sanchez R Cabello R Llopis I Arauzo J Catalan-Giland E Torrella ldquoEnergy performance evaluation of R1234yfR1234ze(E) R600a R290 and R152a as low-GWP R134aalternativesrdquo International Journal of Refrigeration vol 74pp 269ndash282 2017

[16] S V Shaik and T P Ashok Babu ldquoeoretical computation ofperformance of sustainable energy efficient R22 alternativesfor residential air conditionersrdquo Energy Procedia vol 138pp 710ndash716 2017

[17] Z Li H Jiang X Chen and K Liang ldquoComparative study onenergy efficiency of low GWP refrigerants in domestic re-frigerators with capacity modulationrdquo Energy and Buildingsvol 192 pp 93ndash100 2019

[18] S S Vali T P Setty and A Babu ldquoAnalytical computation ofthermodynamic performance parameters of actual vapourcompression refrigeration system with R22 R32 R134aR152a R290 and R1270rdquo MATEC Web of Conferencesvol 144 Article ID 04009 2018

[19] G Relue and S Kopchick New Refrigerants Designation andSafety Classifications E360 Forum Emerson Raleigh NCUSA 2017

[20] ASHRAE Standard 34Designation and Safety Classification ofRefrigerants American Society of Heating Ventilating andAir-Conditioning Engineers Atlanta GA USA 2010

[21] J P Holman Experimental Method for Engineerspp 62ndash65McGraw-Hill Book Company New York NY USA Eighthedition 2001

[22] B O Bolaji ldquoExperimental study of R152a and R32 to replaceR134a in a domestic refrigeratorrdquo Energy vol 35 no 9pp 3793ndash3798 2010

[23] M Fatouh A I Eid and N Nabil ldquoPerformance of water-to-water vapor compression refrigeration system using R22 al-ternatives part I system simulationrdquo Engineering ResearchJournal vol 124 pp M19ndashM43 2009

[24] A Yataganbaba A Kilicarslan and I Kurtbas ldquoExergyanalysis of R1234yf and R1234ze as R134a replacements in atwo evaporator vapour compression refrigeration systemrdquoInternational Journal of Refrigeration vol 60 pp 26ndash37 2015

[25] G F Nellis and S A Klein Engineering Equation Solver (EES)F-Chart Software Wiley Middleton WI USA 2013

[26] R Llopis E Torrella R Cabello and D Sanchez ldquoPerfor-mance evaluation of R404A and R507A refrigerant mixturesin an experimental double-stage vapour compression plantrdquoApplied Energy vol 87 no 5 pp 1546ndash1553 2010

14 Advances in Materials Science and Engineering

0

1

2

3

4

5

6

7

8

0 05 1 15 2 25 3 35

Cool

ing

capa

city

(kW

)

V lowast 103 (m3s)

R134aR152a

R1234yfR1234ze(E)

Figure 17 Cooling capacity versus refrigerant flow rate at Tc 35degC

1

2

3

4

5

6

0 05 1 15 2 25 3 35

COP

R134aR152a

R1234yfR1234ze(E)

V lowast 103 (m3s)

Figure 18 COP versus refrigerant volume flow rate

Advances in Materials Science and Engineering 11

condensing and evaporating temperatures e total exergyefficiency was decreased with the condensing temperaturewhile it was increased with the evaporating temperature For

both condensing and evaporating temperatures the re-frigerant R1234yf has the lowest exergy efficiency followedby R152a e highest exergy efficiency was obtained withR1234ze(E) at different condensing temperatures while atdifferent evaporating temperatures the highest exergy effi-ciency was obtained for R134a From the environmentalthermal and exergy point of view the refrigerant R1234yfhas the best performance among all refrigerants that havebeen investigated to replace R134a in an automotive air-conditioning system

7 Conclusion

Energy and exergy analysis was presented for many envi-ronmentally friendly refrigerants as a drop-in replacementof current high-GWP of R134a in the automotive air-con-ditioning system ree alternative refrigerants which isdistinguished by zero ODP and GWP100lt 150 were inves-tigated with particular reference to the current R134a re-frigerant (GWP100 1430) e exergy destruction of eachcomponent and the exergy efficiency at different condensingtemperatures evaporating temperatures and refrigerantflow rates were presented and the main conclusions aresummarized as follows

(i) For all values of condensing and evaporatingtemperatures a higher system COP was obtained at

01

02

03

04

05

06

07

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degC V = 00031m3s

η tot

al

Figure 20 Total exergy efficiency versus condensing temperature

0

01

02

03

04

05

06

15 20 25 30 35 40 45 50Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degC V = 00031m3s

η tot

al

Figure 21 Total exergy efficiency versus evaporating temperature

R134a R152a R1234yf R1234ze

030

025

020

015

010

005

000

CompressorCondenser

ExpansionEvaporator

Figure 19 Total exergy destruction of each component for dif-ferent refrigerant types

12 Advances in Materials Science and Engineering

a lower compressor speed which was producedfrom slow crankshaft RPM

(ii) A reduction in the cooling capacity by 9 and inCOP by 27 was confirmed when a condensingtemperature increased by 5degC

(iii) Based on the test results the refrigerant R1234ze(E)had the highest coefficient of performance amongall investigated refrigerants

(iv) e refrigerant R1234yf was considered the closestin thermal performance to the refrigerant R134a

(v) e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the totalexergy destruction of R1234yf and R152a was lowerthan that of R134a by 15 and 45 respectively

(vi) e refrigerant R1234ze(E) was the most envi-ronmentally acceptable and had the best energeticand exergetic performance among all the testedrefrigerants

(vii) e highest exergy efficiency was obtained forR1234ze(E) at different condensing temperatureswhile at different evaporating temperatures thehighest exergy efficiency was obtained for R134a

Nomenclature

COP coefficient of performanceCP specific heat kJkgmiddotKEmiddot

x exergy kWh specific enthalpy kJkg_mref refrigerant flow rate kgsp refrigerant pressure kPaQ rate of heat transfer kWRPM revolution per minute minminus 1

s entropy kJkgmiddotKT temperature K_V refrigerant flow rate m3sVCC volumetric cooling capacity kJm3

W compressor power kWGWP100 global warming potential for 100 yearsΡ density kgm3

c coolingcomp compressorcond condenserexp expansionevap evaporatordest destructiondis dischargein inletis isentropicmech mechanicalo dead stateout outlet

Data Availability

e data that support the findings of this study are availableupon request from the corresponding author

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e authors would like to express their sincere gratitude tothe Public Authority for Applied Education and Training(PAAET) Kuwait for supporting and funding this workResearch Project No TS -16-12 Research Project TitleldquoEnergetic and exergetic analysis of R1234yf R1234ze andR152 as a low-GWP alternatives of R134a in automotive airconditioningrdquo Special appreciation to Refrigeration and AirConditioning Department Faculty of Industrial EducationHelwan University Egypt for the technical assistance ex-tended to the authors

References

[1] I P Koronaki D Cowan G Maidment et al ldquoRefrigerantemissions and leakage prevention across Europemdashresultsfrom the real skills Europe projectrdquo Energy vol 45 no 1pp 71ndash80 2012

[2] Environmental Protection Agency Protection of StratosphericOzone Change of Listing Status for Certain Substitutes underthe Significant New Alternatives Policy Program Rules andRegulations Environmental Protection Agency EPAWashington DC USA 2015

[3] I Dincer and A R Marc Exergy Energy Environment andSustainable Development Elsevier Amsterdam NetherlandsSecond edition 2016

[4] H Cho and C Park ldquoExperimental investigation of perfor-mance and exergy analysis of automotive air conditioningsystems using refrigerant R1234yf at various compressorspeedsrdquo Applied 4ermal Engineering vol 101 pp 30ndash372016

[5] B Jemaa R Mansouri I Boukholda and A Bellagi ldquoEnergyand exergy investigation of R1234ze(E) as R134a replacementin vapor compression chillersrdquo International Journal of Hy-drogen Energy vol 42 no 17 pp 12877ndash12887 2017

[6] K Zhang Y Zhu J Liu X Niu and X Yuan ldquoExergy andenergy analysis of a double evaporating temperature chillerrdquoEnergy and Buildings vol 165 pp 464ndash471 2018

[7] J K Verma A Satsangi and V Chaturani ldquoA review ofalternative to R134a (CH3CH2F) refrigerantrdquo InternationalJournal of Emerging Technology and Advanced Engineeringvol 3 no 1 pp 300ndash304 2013

[8] J Garcia T Ali W M Duarte A Khosravi and L MachadoldquoComparison of transient response of an evaporatormodel forwater refrigeration system working with R1234yf as a drop-inreplacement for R134ardquo International Journal of Refrigera-tion vol 91 pp 211ndash222 2018

[9] E Navarro I O Martınez-Galvan J Nohales andJ Gonzalvez-Macia ldquoComparative experimental study of anopen piston compressor working with R-1234yf R-134a andR-290rdquo International Journal of Refrigeration vol 36 no 3pp 768ndash775 2013

[10] J Navarro-Esbrı J M Mendoza-Miranda A Mota-BabiloniA Barraga-Cervera A Barragan-Cervera and J M Belman-Flores ldquoExperimental analysis of R1234yf as a drop-in re-placement for R134a in a vapor compression systemrdquo In-ternational Journal of Refrigeration vol 36 no 3pp 870ndash880 2013

Advances in Materials Science and Engineering 13

[11] A Gomaa ldquoPerformance characteristics of automotive airconditioning system with refrigerant R134a and its alterna-tivesrdquo International Journal of Energy and Power Engineeringvol 4 no 3 pp 168ndash177 2015

[12] Y Lee and D Jung ldquoA brief performance comparison ofR1234yf and R134a in a bench tester for automobile appli-cationsrdquo Applied 4ermal Engineering vol 35 pp 240ndash2422012

[13] J M Belman-Flores V H Rangel-Hernandez S Uson andC Rubio-Maya ldquoEnergy and exergy analysis of R1234yf asdrop-in replacement for R134a in a domestic refrigerationsystemrdquo Energy vol 132 pp 116ndash125 2017

[14] M Joybari M H Hatamipour A Rahimi and F ModarresldquoExergy analysis and optimization of R600a as a replacementof R134a in a domestic refrigerator systemrdquo InternationalJournal of Refrigeration vol 36 no 4 pp 1233ndash1242 2013

[15] D Sanchez R Cabello R Llopis I Arauzo J Catalan-Giland E Torrella ldquoEnergy performance evaluation of R1234yfR1234ze(E) R600a R290 and R152a as low-GWP R134aalternativesrdquo International Journal of Refrigeration vol 74pp 269ndash282 2017

[16] S V Shaik and T P Ashok Babu ldquoeoretical computation ofperformance of sustainable energy efficient R22 alternativesfor residential air conditionersrdquo Energy Procedia vol 138pp 710ndash716 2017

[17] Z Li H Jiang X Chen and K Liang ldquoComparative study onenergy efficiency of low GWP refrigerants in domestic re-frigerators with capacity modulationrdquo Energy and Buildingsvol 192 pp 93ndash100 2019

[18] S S Vali T P Setty and A Babu ldquoAnalytical computation ofthermodynamic performance parameters of actual vapourcompression refrigeration system with R22 R32 R134aR152a R290 and R1270rdquo MATEC Web of Conferencesvol 144 Article ID 04009 2018

[19] G Relue and S Kopchick New Refrigerants Designation andSafety Classifications E360 Forum Emerson Raleigh NCUSA 2017

[20] ASHRAE Standard 34Designation and Safety Classification ofRefrigerants American Society of Heating Ventilating andAir-Conditioning Engineers Atlanta GA USA 2010

[21] J P Holman Experimental Method for Engineerspp 62ndash65McGraw-Hill Book Company New York NY USA Eighthedition 2001

[22] B O Bolaji ldquoExperimental study of R152a and R32 to replaceR134a in a domestic refrigeratorrdquo Energy vol 35 no 9pp 3793ndash3798 2010

[23] M Fatouh A I Eid and N Nabil ldquoPerformance of water-to-water vapor compression refrigeration system using R22 al-ternatives part I system simulationrdquo Engineering ResearchJournal vol 124 pp M19ndashM43 2009

[24] A Yataganbaba A Kilicarslan and I Kurtbas ldquoExergyanalysis of R1234yf and R1234ze as R134a replacements in atwo evaporator vapour compression refrigeration systemrdquoInternational Journal of Refrigeration vol 60 pp 26ndash37 2015

[25] G F Nellis and S A Klein Engineering Equation Solver (EES)F-Chart Software Wiley Middleton WI USA 2013

[26] R Llopis E Torrella R Cabello and D Sanchez ldquoPerfor-mance evaluation of R404A and R507A refrigerant mixturesin an experimental double-stage vapour compression plantrdquoApplied Energy vol 87 no 5 pp 1546ndash1553 2010

14 Advances in Materials Science and Engineering

condensing and evaporating temperatures e total exergyefficiency was decreased with the condensing temperaturewhile it was increased with the evaporating temperature For

both condensing and evaporating temperatures the re-frigerant R1234yf has the lowest exergy efficiency followedby R152a e highest exergy efficiency was obtained withR1234ze(E) at different condensing temperatures while atdifferent evaporating temperatures the highest exergy effi-ciency was obtained for R134a From the environmentalthermal and exergy point of view the refrigerant R1234yfhas the best performance among all refrigerants that havebeen investigated to replace R134a in an automotive air-conditioning system

7 Conclusion

Energy and exergy analysis was presented for many envi-ronmentally friendly refrigerants as a drop-in replacementof current high-GWP of R134a in the automotive air-con-ditioning system ree alternative refrigerants which isdistinguished by zero ODP and GWP100lt 150 were inves-tigated with particular reference to the current R134a re-frigerant (GWP100 1430) e exergy destruction of eachcomponent and the exergy efficiency at different condensingtemperatures evaporating temperatures and refrigerantflow rates were presented and the main conclusions aresummarized as follows

(i) For all values of condensing and evaporatingtemperatures a higher system COP was obtained at

01

02

03

04

05

06

07

ndash20 ndash10 0 10 20Te (degC)

R134aR152a

R1234yfR1234ze(E)

Tc = 35degC V = 00031m3s

η tot

al

Figure 20 Total exergy efficiency versus condensing temperature

0

01

02

03

04

05

06

15 20 25 30 35 40 45 50Tc (degC)

R134aR152a

R1234yfR1234ze(E)

Te = 10degC V = 00031m3s

η tot

al

Figure 21 Total exergy efficiency versus evaporating temperature

R134a R152a R1234yf R1234ze

030

025

020

015

010

005

000

CompressorCondenser

ExpansionEvaporator

Figure 19 Total exergy destruction of each component for dif-ferent refrigerant types

12 Advances in Materials Science and Engineering

a lower compressor speed which was producedfrom slow crankshaft RPM

(ii) A reduction in the cooling capacity by 9 and inCOP by 27 was confirmed when a condensingtemperature increased by 5degC

(iii) Based on the test results the refrigerant R1234ze(E)had the highest coefficient of performance amongall investigated refrigerants

(iv) e refrigerant R1234yf was considered the closestin thermal performance to the refrigerant R134a

(v) e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the totalexergy destruction of R1234yf and R152a was lowerthan that of R134a by 15 and 45 respectively

(vi) e refrigerant R1234ze(E) was the most envi-ronmentally acceptable and had the best energeticand exergetic performance among all the testedrefrigerants

(vii) e highest exergy efficiency was obtained forR1234ze(E) at different condensing temperatureswhile at different evaporating temperatures thehighest exergy efficiency was obtained for R134a

Nomenclature

COP coefficient of performanceCP specific heat kJkgmiddotKEmiddot

x exergy kWh specific enthalpy kJkg_mref refrigerant flow rate kgsp refrigerant pressure kPaQ rate of heat transfer kWRPM revolution per minute minminus 1

s entropy kJkgmiddotKT temperature K_V refrigerant flow rate m3sVCC volumetric cooling capacity kJm3

W compressor power kWGWP100 global warming potential for 100 yearsΡ density kgm3

c coolingcomp compressorcond condenserexp expansionevap evaporatordest destructiondis dischargein inletis isentropicmech mechanicalo dead stateout outlet

Data Availability

e data that support the findings of this study are availableupon request from the corresponding author

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e authors would like to express their sincere gratitude tothe Public Authority for Applied Education and Training(PAAET) Kuwait for supporting and funding this workResearch Project No TS -16-12 Research Project TitleldquoEnergetic and exergetic analysis of R1234yf R1234ze andR152 as a low-GWP alternatives of R134a in automotive airconditioningrdquo Special appreciation to Refrigeration and AirConditioning Department Faculty of Industrial EducationHelwan University Egypt for the technical assistance ex-tended to the authors

References

[1] I P Koronaki D Cowan G Maidment et al ldquoRefrigerantemissions and leakage prevention across Europemdashresultsfrom the real skills Europe projectrdquo Energy vol 45 no 1pp 71ndash80 2012

[2] Environmental Protection Agency Protection of StratosphericOzone Change of Listing Status for Certain Substitutes underthe Significant New Alternatives Policy Program Rules andRegulations Environmental Protection Agency EPAWashington DC USA 2015

[3] I Dincer and A R Marc Exergy Energy Environment andSustainable Development Elsevier Amsterdam NetherlandsSecond edition 2016

[4] H Cho and C Park ldquoExperimental investigation of perfor-mance and exergy analysis of automotive air conditioningsystems using refrigerant R1234yf at various compressorspeedsrdquo Applied 4ermal Engineering vol 101 pp 30ndash372016

[5] B Jemaa R Mansouri I Boukholda and A Bellagi ldquoEnergyand exergy investigation of R1234ze(E) as R134a replacementin vapor compression chillersrdquo International Journal of Hy-drogen Energy vol 42 no 17 pp 12877ndash12887 2017

[6] K Zhang Y Zhu J Liu X Niu and X Yuan ldquoExergy andenergy analysis of a double evaporating temperature chillerrdquoEnergy and Buildings vol 165 pp 464ndash471 2018

[7] J K Verma A Satsangi and V Chaturani ldquoA review ofalternative to R134a (CH3CH2F) refrigerantrdquo InternationalJournal of Emerging Technology and Advanced Engineeringvol 3 no 1 pp 300ndash304 2013

[8] J Garcia T Ali W M Duarte A Khosravi and L MachadoldquoComparison of transient response of an evaporatormodel forwater refrigeration system working with R1234yf as a drop-inreplacement for R134ardquo International Journal of Refrigera-tion vol 91 pp 211ndash222 2018

[9] E Navarro I O Martınez-Galvan J Nohales andJ Gonzalvez-Macia ldquoComparative experimental study of anopen piston compressor working with R-1234yf R-134a andR-290rdquo International Journal of Refrigeration vol 36 no 3pp 768ndash775 2013

[10] J Navarro-Esbrı J M Mendoza-Miranda A Mota-BabiloniA Barraga-Cervera A Barragan-Cervera and J M Belman-Flores ldquoExperimental analysis of R1234yf as a drop-in re-placement for R134a in a vapor compression systemrdquo In-ternational Journal of Refrigeration vol 36 no 3pp 870ndash880 2013

Advances in Materials Science and Engineering 13

[11] A Gomaa ldquoPerformance characteristics of automotive airconditioning system with refrigerant R134a and its alterna-tivesrdquo International Journal of Energy and Power Engineeringvol 4 no 3 pp 168ndash177 2015

[12] Y Lee and D Jung ldquoA brief performance comparison ofR1234yf and R134a in a bench tester for automobile appli-cationsrdquo Applied 4ermal Engineering vol 35 pp 240ndash2422012

[13] J M Belman-Flores V H Rangel-Hernandez S Uson andC Rubio-Maya ldquoEnergy and exergy analysis of R1234yf asdrop-in replacement for R134a in a domestic refrigerationsystemrdquo Energy vol 132 pp 116ndash125 2017

[14] M Joybari M H Hatamipour A Rahimi and F ModarresldquoExergy analysis and optimization of R600a as a replacementof R134a in a domestic refrigerator systemrdquo InternationalJournal of Refrigeration vol 36 no 4 pp 1233ndash1242 2013

[15] D Sanchez R Cabello R Llopis I Arauzo J Catalan-Giland E Torrella ldquoEnergy performance evaluation of R1234yfR1234ze(E) R600a R290 and R152a as low-GWP R134aalternativesrdquo International Journal of Refrigeration vol 74pp 269ndash282 2017

[16] S V Shaik and T P Ashok Babu ldquoeoretical computation ofperformance of sustainable energy efficient R22 alternativesfor residential air conditionersrdquo Energy Procedia vol 138pp 710ndash716 2017

[17] Z Li H Jiang X Chen and K Liang ldquoComparative study onenergy efficiency of low GWP refrigerants in domestic re-frigerators with capacity modulationrdquo Energy and Buildingsvol 192 pp 93ndash100 2019

[18] S S Vali T P Setty and A Babu ldquoAnalytical computation ofthermodynamic performance parameters of actual vapourcompression refrigeration system with R22 R32 R134aR152a R290 and R1270rdquo MATEC Web of Conferencesvol 144 Article ID 04009 2018

[19] G Relue and S Kopchick New Refrigerants Designation andSafety Classifications E360 Forum Emerson Raleigh NCUSA 2017

[20] ASHRAE Standard 34Designation and Safety Classification ofRefrigerants American Society of Heating Ventilating andAir-Conditioning Engineers Atlanta GA USA 2010

[21] J P Holman Experimental Method for Engineerspp 62ndash65McGraw-Hill Book Company New York NY USA Eighthedition 2001

[22] B O Bolaji ldquoExperimental study of R152a and R32 to replaceR134a in a domestic refrigeratorrdquo Energy vol 35 no 9pp 3793ndash3798 2010

[23] M Fatouh A I Eid and N Nabil ldquoPerformance of water-to-water vapor compression refrigeration system using R22 al-ternatives part I system simulationrdquo Engineering ResearchJournal vol 124 pp M19ndashM43 2009

[24] A Yataganbaba A Kilicarslan and I Kurtbas ldquoExergyanalysis of R1234yf and R1234ze as R134a replacements in atwo evaporator vapour compression refrigeration systemrdquoInternational Journal of Refrigeration vol 60 pp 26ndash37 2015

[25] G F Nellis and S A Klein Engineering Equation Solver (EES)F-Chart Software Wiley Middleton WI USA 2013

[26] R Llopis E Torrella R Cabello and D Sanchez ldquoPerfor-mance evaluation of R404A and R507A refrigerant mixturesin an experimental double-stage vapour compression plantrdquoApplied Energy vol 87 no 5 pp 1546ndash1553 2010

14 Advances in Materials Science and Engineering

a lower compressor speed which was producedfrom slow crankshaft RPM

(ii) A reduction in the cooling capacity by 9 and inCOP by 27 was confirmed when a condensingtemperature increased by 5degC

(iii) Based on the test results the refrigerant R1234ze(E)had the highest coefficient of performance amongall investigated refrigerants

(iv) e refrigerant R1234yf was considered the closestin thermal performance to the refrigerant R134a

(v) e total exergy destruction of R1234ze(E) washigher than that of R134a by 54 while the totalexergy destruction of R1234yf and R152a was lowerthan that of R134a by 15 and 45 respectively

(vi) e refrigerant R1234ze(E) was the most envi-ronmentally acceptable and had the best energeticand exergetic performance among all the testedrefrigerants

(vii) e highest exergy efficiency was obtained forR1234ze(E) at different condensing temperatureswhile at different evaporating temperatures thehighest exergy efficiency was obtained for R134a

Nomenclature

COP coefficient of performanceCP specific heat kJkgmiddotKEmiddot

x exergy kWh specific enthalpy kJkg_mref refrigerant flow rate kgsp refrigerant pressure kPaQ rate of heat transfer kWRPM revolution per minute minminus 1

s entropy kJkgmiddotKT temperature K_V refrigerant flow rate m3sVCC volumetric cooling capacity kJm3

W compressor power kWGWP100 global warming potential for 100 yearsΡ density kgm3

c coolingcomp compressorcond condenserexp expansionevap evaporatordest destructiondis dischargein inletis isentropicmech mechanicalo dead stateout outlet

Data Availability

e data that support the findings of this study are availableupon request from the corresponding author

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e authors would like to express their sincere gratitude tothe Public Authority for Applied Education and Training(PAAET) Kuwait for supporting and funding this workResearch Project No TS -16-12 Research Project TitleldquoEnergetic and exergetic analysis of R1234yf R1234ze andR152 as a low-GWP alternatives of R134a in automotive airconditioningrdquo Special appreciation to Refrigeration and AirConditioning Department Faculty of Industrial EducationHelwan University Egypt for the technical assistance ex-tended to the authors

References

[1] I P Koronaki D Cowan G Maidment et al ldquoRefrigerantemissions and leakage prevention across Europemdashresultsfrom the real skills Europe projectrdquo Energy vol 45 no 1pp 71ndash80 2012

[2] Environmental Protection Agency Protection of StratosphericOzone Change of Listing Status for Certain Substitutes underthe Significant New Alternatives Policy Program Rules andRegulations Environmental Protection Agency EPAWashington DC USA 2015

[3] I Dincer and A R Marc Exergy Energy Environment andSustainable Development Elsevier Amsterdam NetherlandsSecond edition 2016

[4] H Cho and C Park ldquoExperimental investigation of perfor-mance and exergy analysis of automotive air conditioningsystems using refrigerant R1234yf at various compressorspeedsrdquo Applied 4ermal Engineering vol 101 pp 30ndash372016

[5] B Jemaa R Mansouri I Boukholda and A Bellagi ldquoEnergyand exergy investigation of R1234ze(E) as R134a replacementin vapor compression chillersrdquo International Journal of Hy-drogen Energy vol 42 no 17 pp 12877ndash12887 2017

[6] K Zhang Y Zhu J Liu X Niu and X Yuan ldquoExergy andenergy analysis of a double evaporating temperature chillerrdquoEnergy and Buildings vol 165 pp 464ndash471 2018

[7] J K Verma A Satsangi and V Chaturani ldquoA review ofalternative to R134a (CH3CH2F) refrigerantrdquo InternationalJournal of Emerging Technology and Advanced Engineeringvol 3 no 1 pp 300ndash304 2013

[8] J Garcia T Ali W M Duarte A Khosravi and L MachadoldquoComparison of transient response of an evaporatormodel forwater refrigeration system working with R1234yf as a drop-inreplacement for R134ardquo International Journal of Refrigera-tion vol 91 pp 211ndash222 2018

[9] E Navarro I O Martınez-Galvan J Nohales andJ Gonzalvez-Macia ldquoComparative experimental study of anopen piston compressor working with R-1234yf R-134a andR-290rdquo International Journal of Refrigeration vol 36 no 3pp 768ndash775 2013

[10] J Navarro-Esbrı J M Mendoza-Miranda A Mota-BabiloniA Barraga-Cervera A Barragan-Cervera and J M Belman-Flores ldquoExperimental analysis of R1234yf as a drop-in re-placement for R134a in a vapor compression systemrdquo In-ternational Journal of Refrigeration vol 36 no 3pp 870ndash880 2013

Advances in Materials Science and Engineering 13

[11] A Gomaa ldquoPerformance characteristics of automotive airconditioning system with refrigerant R134a and its alterna-tivesrdquo International Journal of Energy and Power Engineeringvol 4 no 3 pp 168ndash177 2015

[12] Y Lee and D Jung ldquoA brief performance comparison ofR1234yf and R134a in a bench tester for automobile appli-cationsrdquo Applied 4ermal Engineering vol 35 pp 240ndash2422012

[13] J M Belman-Flores V H Rangel-Hernandez S Uson andC Rubio-Maya ldquoEnergy and exergy analysis of R1234yf asdrop-in replacement for R134a in a domestic refrigerationsystemrdquo Energy vol 132 pp 116ndash125 2017

[14] M Joybari M H Hatamipour A Rahimi and F ModarresldquoExergy analysis and optimization of R600a as a replacementof R134a in a domestic refrigerator systemrdquo InternationalJournal of Refrigeration vol 36 no 4 pp 1233ndash1242 2013

[15] D Sanchez R Cabello R Llopis I Arauzo J Catalan-Giland E Torrella ldquoEnergy performance evaluation of R1234yfR1234ze(E) R600a R290 and R152a as low-GWP R134aalternativesrdquo International Journal of Refrigeration vol 74pp 269ndash282 2017

[16] S V Shaik and T P Ashok Babu ldquoeoretical computation ofperformance of sustainable energy efficient R22 alternativesfor residential air conditionersrdquo Energy Procedia vol 138pp 710ndash716 2017

[17] Z Li H Jiang X Chen and K Liang ldquoComparative study onenergy efficiency of low GWP refrigerants in domestic re-frigerators with capacity modulationrdquo Energy and Buildingsvol 192 pp 93ndash100 2019

[18] S S Vali T P Setty and A Babu ldquoAnalytical computation ofthermodynamic performance parameters of actual vapourcompression refrigeration system with R22 R32 R134aR152a R290 and R1270rdquo MATEC Web of Conferencesvol 144 Article ID 04009 2018

[19] G Relue and S Kopchick New Refrigerants Designation andSafety Classifications E360 Forum Emerson Raleigh NCUSA 2017

[20] ASHRAE Standard 34Designation and Safety Classification ofRefrigerants American Society of Heating Ventilating andAir-Conditioning Engineers Atlanta GA USA 2010

[21] J P Holman Experimental Method for Engineerspp 62ndash65McGraw-Hill Book Company New York NY USA Eighthedition 2001

[22] B O Bolaji ldquoExperimental study of R152a and R32 to replaceR134a in a domestic refrigeratorrdquo Energy vol 35 no 9pp 3793ndash3798 2010

[23] M Fatouh A I Eid and N Nabil ldquoPerformance of water-to-water vapor compression refrigeration system using R22 al-ternatives part I system simulationrdquo Engineering ResearchJournal vol 124 pp M19ndashM43 2009

[24] A Yataganbaba A Kilicarslan and I Kurtbas ldquoExergyanalysis of R1234yf and R1234ze as R134a replacements in atwo evaporator vapour compression refrigeration systemrdquoInternational Journal of Refrigeration vol 60 pp 26ndash37 2015

[25] G F Nellis and S A Klein Engineering Equation Solver (EES)F-Chart Software Wiley Middleton WI USA 2013

[26] R Llopis E Torrella R Cabello and D Sanchez ldquoPerfor-mance evaluation of R404A and R507A refrigerant mixturesin an experimental double-stage vapour compression plantrdquoApplied Energy vol 87 no 5 pp 1546ndash1553 2010

14 Advances in Materials Science and Engineering

[11] A Gomaa ldquoPerformance characteristics of automotive airconditioning system with refrigerant R134a and its alterna-tivesrdquo International Journal of Energy and Power Engineeringvol 4 no 3 pp 168ndash177 2015

[12] Y Lee and D Jung ldquoA brief performance comparison ofR1234yf and R134a in a bench tester for automobile appli-cationsrdquo Applied 4ermal Engineering vol 35 pp 240ndash2422012

[13] J M Belman-Flores V H Rangel-Hernandez S Uson andC Rubio-Maya ldquoEnergy and exergy analysis of R1234yf asdrop-in replacement for R134a in a domestic refrigerationsystemrdquo Energy vol 132 pp 116ndash125 2017

[14] M Joybari M H Hatamipour A Rahimi and F ModarresldquoExergy analysis and optimization of R600a as a replacementof R134a in a domestic refrigerator systemrdquo InternationalJournal of Refrigeration vol 36 no 4 pp 1233ndash1242 2013

[15] D Sanchez R Cabello R Llopis I Arauzo J Catalan-Giland E Torrella ldquoEnergy performance evaluation of R1234yfR1234ze(E) R600a R290 and R152a as low-GWP R134aalternativesrdquo International Journal of Refrigeration vol 74pp 269ndash282 2017

[16] S V Shaik and T P Ashok Babu ldquoeoretical computation ofperformance of sustainable energy efficient R22 alternativesfor residential air conditionersrdquo Energy Procedia vol 138pp 710ndash716 2017

[17] Z Li H Jiang X Chen and K Liang ldquoComparative study onenergy efficiency of low GWP refrigerants in domestic re-frigerators with capacity modulationrdquo Energy and Buildingsvol 192 pp 93ndash100 2019

[18] S S Vali T P Setty and A Babu ldquoAnalytical computation ofthermodynamic performance parameters of actual vapourcompression refrigeration system with R22 R32 R134aR152a R290 and R1270rdquo MATEC Web of Conferencesvol 144 Article ID 04009 2018

[19] G Relue and S Kopchick New Refrigerants Designation andSafety Classifications E360 Forum Emerson Raleigh NCUSA 2017

[20] ASHRAE Standard 34Designation and Safety Classification ofRefrigerants American Society of Heating Ventilating andAir-Conditioning Engineers Atlanta GA USA 2010

[21] J P Holman Experimental Method for Engineerspp 62ndash65McGraw-Hill Book Company New York NY USA Eighthedition 2001

[22] B O Bolaji ldquoExperimental study of R152a and R32 to replaceR134a in a domestic refrigeratorrdquo Energy vol 35 no 9pp 3793ndash3798 2010

[23] M Fatouh A I Eid and N Nabil ldquoPerformance of water-to-water vapor compression refrigeration system using R22 al-ternatives part I system simulationrdquo Engineering ResearchJournal vol 124 pp M19ndashM43 2009

[24] A Yataganbaba A Kilicarslan and I Kurtbas ldquoExergyanalysis of R1234yf and R1234ze as R134a replacements in atwo evaporator vapour compression refrigeration systemrdquoInternational Journal of Refrigeration vol 60 pp 26ndash37 2015

[25] G F Nellis and S A Klein Engineering Equation Solver (EES)F-Chart Software Wiley Middleton WI USA 2013

[26] R Llopis E Torrella R Cabello and D Sanchez ldquoPerfor-mance evaluation of R404A and R507A refrigerant mixturesin an experimental double-stage vapour compression plantrdquoApplied Energy vol 87 no 5 pp 1546ndash1553 2010

14 Advances in Materials Science and Engineering