ThedailyaveragevaluesofthemeasureddataandcalculatedresultsaregiveninTable4.Thesevaluesconsistoftheaveragevaluesofthemeasurementsof21recordedfrom8.00a.m.to18.00p.m.withanintervalof30min.AsseeninTable4,thecondensationpressuresinaverageareabout15barand,thisvalueisveryreasonablebecausethemaximumdischargepressurelimitofthecompressoris29bar.
8
8
6Teai-Teao (°C)
6Teai-Teao (°C)
44
2
2
008:00
10:00
12:0014:00Time of day
16:0018:00
008:00
10:0012:0014:0016:0018:00
Time of day
With(Jan. 20)andwithout (Jan. 23)SHCHEWith(Feb. 05)andwithout(Feb. 03)SHCHE
Fig.6.Variationsininlet-outlettemperaturedifferences(TeaiÀTeao)oftheantifreeze-watersolutiontotheGHEunitwithtimeofdayforthesystemswithandwithoutSHCHE.
K.Bakirci,D.Colak/Energy44(2012)996e1004
1003
Table4
MeasuredandcalculatedparametersinaverageforthesystemwithoutSHCHE(January23,2010andFebruary03,2010).Item
Jan.23,Feb.03,Unit
Total
2010
2010
uncertainty(%)MeasuredparametersEvaporationpressure2.642.59BarÆ2.05Condensationpressure14.7714.69BarÆ2.05Temperatureofrefrigerant2.351.52 C
Æ1.01atthecompressorinletTemperatureofrefrigerant81.2781.31
CÆ1.01atthecondenserinletTemperatureofrefrigerant48.4347.73
CÆ1.01atthecondenseroutletTemperatureofrefrigerantÀ7.83À8.24
C
Æ1.01attheevaporatorinletCondensingtemperature54.6054.38
CÆ1.01EvaporatingtemperatureÀ2.95À3.46
CÆ1.01Flowrateofantifreeze-water0.2880.333kgsÀ1
Æ7.15solutionintheevaporatorFlowrateofwaterinthe0.267
0.324
kgsÀ1
Æ7.15
heatingunitorthecondenser
Indoorairtemperature
11.749.73
CÆ1.01Currentofcirculatingpump0.600.60AÆ1.00attheGHE
Currentofcirculatingpump0.690.69AÆ1.00attheheatingunitTwo-phasevoltage220.0220.0VÆ1.00Temperatureof
1.74
1.11
C
Æ1.01
antifreeze-watersolutionattheevaporatorinletTemperatureof
À2.30À2.65
CÆ1.01
antifreeze-watersolutionattheevaporatoroutletSupplywatertemperature49.5648.41
CÆ1.01oftheheatingunit
Returnwatertemperature45.1144.68
C
Æ1.01oftheheatingunit
Powerinputtothecompressor2.001.85kWÆ1.00Calculatedparameters
Powerinputtothecirculating0.1190.119kWÆ3.00pumpattheGHE
Powerinputtothecirculating0.1370.137kWÆ3.00pumpattheheatingunitHeatingloadofthecondenser4.9555.207kWÆ7.23Coolingloadoftheevaporator3.6023.907kWÆ7.23HeatingCOP(theheatpump)
2.4702.809eÆ7.30HeatingCOPS(theoverallsystem)
2.190
2.621
e
Æ7.28
6.Conclusions
Theperformanceofaverticalgroundsourceheatpumpsystemwasinvestigatedexperimentally.Inthestudy,theexperimentalresultsweregivenforthemonthsofJanuaryandFebruaryintheheatingseasonof2010.TheexperimentalresultsindicatethattheaveragevaluesoftheCOPandtheCOPSareapproximately2.31and2.07withSHCHEand2.47and2.19withoutSHCHEinJanuary,whiletheyareapproximately2.73and2.55withSHCHEand2.81and2.62withoutSHCHEinFebruary,respectively.Additionally,theresultsshowthatthesystemswithandwithoutSHCHEarenotverydifferentintermsofthecoef cientofperformancebutthesystemwithSHCHEcanbepreferredforhighercondenseroutlettemperature.
Theheatpumpsystemsareenvironmentallyfriendly.Theinitialcostsoftheheatpumpsystemsarehigher,buttheyhavelowoperating,maintenance,andlifecyclecostsandalongerlifeexpectancythanmostconventionalsystems.Also,theheatpumpsystemsprovideheating,coolingandhotwaterinmanyapplications.Thegroundsourceheatpumpsystemspresent
tremendousenvironmentalbene tswhencomparedtotheconventionalsystems.Therefore,thesesystemscanbeusedtominimizeenvironmentalimpactsandairemission.
Acknowledgment
TheauthorsthanktheAtatürkUniversityResearchFund(ProjectNo:2005/25)andTheScienti candTechnologicalResearchCouncilofTurkey(TUBITAK,ProjectNo:106M068)duetotheir nancialsupportforthisresearch.
References
[1]KaragozS,BakirciK.SustainableenergydevelopmentinTurkey.Energy
Sources(PartB)2010;5(1):63e73.
[2]BilenK,OzyurtO,BakirciK,KarsliS,ErdoganS,YilmazM,etal.Energy
production,consumption,andenvironmentalpollutionforsustainabledevelopment:acasestudyinTurkey.RenewableandSustainableEnergyReviews2008;12(6):1529e61.
[3]KaygusuzK.RenewableandsustainableenergyuseinTurkey:areview.
RenewandSustainableEnergyReviews2002;6(4):339e66.
[4]DincerI.Renewableenergyandsustainabledevelopment:acrucialreview.
RenewandSustainableEnergyReviews2000;4(2):157e75.
[5]WoodCJ,LiuH,RiffatSB.Aninvestigationoftheheatpumpperformanceand
groundtemperatureofapiledfoundationheatexchangersystemforaresi-dentialbuilding.Energy2010;35(12):4932e40.
[6]OmerAM.Ground-sourceheatpumpssystemsandapplications.Renewable
andSustainableEnergyReviews2008;12:344e71.
[7]LienauPJ.Geothermalheatpumpperformanceandutilityprogramsinthe