Averagesolarradiation(MJ/m2.day)Averagewindvelocity(m/s)
GroundheatexchangerinformationType
Diameter(mm)Deep(m)
HeatpumpinformationCapacity(kW)CompressortypeEvaporatortypeCondensertype
Compressorpowerinput(kW)Capacityofcooling(kW)
Maximumdischargepressure(bar)Compressordisplacement(m3/h)Refrigeranttype
K.Bakirci,D.Colak/Energy44(2012)996e1004
4.7À2.812.264.66.415.62.7Vertical32
2Â53
7
HermeticscrollPlatePlate
2.61(3.5HP)5.7299.4R-134a
5.Resultsanddiscussions
Inthisstudy,theperformanceofthegroundsourceheatpumpsystemwithverticalgroundheatexchangerwas
experimentallyanalyzedinErzurum,Turkey.Theexperimentalresultswereobtainedintheheatingseasonof2010.JanuaryandFebruaryarethecoolestmonthsoftheheatingseasonintheregion.Therefore,theexperimentaldataweregivenonlyforthesemonths.
Thetechnicaldetailsoftheexperimentalset-uparegiveninTable3.Fig.2showsthevariationsintheinlet-outlettempera-turesoftheheattransfer uidstotheevaporatorandthecondenserwithtimeofdayforthesystemswithandwithoutSHCHE.AsseeninFig.2,whilethetemperatureofthecondenseroutlet(Tcwo)forJanuaryvariesinthebandof49.6e61.0 C,itvariesinthebandof47.9e51.4 CforFebruaryduringtheexper-imentscarriedoutwithSHCHE.ThesametemperatureforJanuaryandFebruaryvariesinthebandof47.7e53.0 Cand47.2e50.2 C,respectively,duringtheexperimentscarriedoutwithoutSHCHE.Fig.2showsalsothehourlyvariationsoftheinlettemperaturesoftheevaporator.Theinlettemperaturesoftheevaporatorhavethemaximumvalueinlocaltimeof08:00foralltheexperimentalconditions.
Fig.3showsthevariationsinthecondenserpower,theGHE(evaporator)powerandthecompressorpowerwiththetimeofdayforthesystemswithandwithoutSHCHE.Fig.4showsthedailyvariationsofthegroundtemperatureatthedepthof53mforthesystemswithandwithoutSHCHE.AsseeninFig.4,theaveragegroundtemperaturesforthesystemswithandwithoutSHCHEare6.6and6.5 CforJanuary,respectively.ThesetemperaturesforthesystemswithandwithoutSHCHEare5.7and5.8 CforFebruary,respectively.
a
Temperature (°C)
20151050-5-1008:00
2015
Temperature (°C)
16:00
18:00
1050-5
10:0012:0014:00
b
Time of day
7060
-1008:00
7060Temperature (°C)
5040302008:00
10:0012:0014:0016:0018:00
Time of day
Temperature (°C)
5040302008:00
10:0012:0014:0016:0018:00
Time of day
10:0012:0014:0016:0018:00
Time of day
With (Jan. 20) and without (Jan. 23) SHCHE With (Feb. 05) and without (Feb. 03) SHCHE
Fig.2.Variationsininlet-outlettemperatureswithtimeofdayforthesystemswithandwithoutSHCHE,fora)Evaporatorandb)Condenser.
K.Bakirci,D.Colak/Energy44(2012)996e10041001
a
Condenser power (kW)
8
8
Condenser power (kW)
66
44
2
2
008:00
10:0012:0014:0016:0018:00
008:00
10:0012:0014:0016:0018:00
b
GHE (evaporator) power (kW)
Time of day
8
Time of day
8GHE (evaporator) power (kW)
66
44
22
008:00
10:0012:0014:0016:0018:00
008:00
10:0012:0014:0016:0018:00
Time of day
Time of day
c
Compressor power (kW)
88Compressor power (kW)
66
44
22
008:00
10:0012:0014:0016:0018:00
008:00
10:0012:0014:0016:0018:00
Time of dayTime of day
With (Jan. 20) and without (Jan. 23) SHCHE With (Feb. 05) and without (Feb. 03) SHCHE
Fig.3.DailypowervaluesofthesystemswithandwithoutSHCHE,for(a)Condenserpower,(b)GHE(evaporator)powerand(c)Compressorpower.
14
14Ground temperature (°C)
12Ground temperature (°C)
108642008:00
12108642008:00
10:0012:0014:0016:0018:00
10:00
Time of day
12:0014:00Time of day
16:0018:00
With (Jan. 20) and without (Jan. 23) SHCHEWith (Feb. 05) and without (Feb. 03) SHCHE
Fig.4.Dailyvariationsofthegroundtemperatureatthedepthof53mforthesystemswithandwithoutSHCHE.
1002K.Bakirci,D.Colak/Energy44(2012)996e1004
a
654COP
321008:00
654COP
321008:00
10:00
12:0014:00Time of day
16:0018:0010:00
12:0014:00Time of day
16:0018:00
b
654COPS
COPS
6
54321008:00
321008:00
10:00
12:0014:00Time of day
16:0018:0010:00
12:0014:00Time of day
16:0018:00
With (Jan. 20) and without (Jan. 23) SHCHE With (Feb. 05) and without (Feb. 03) SHCHE
Fig.5.Performancecoef cientsversustimeofdayforthesystemswithandwithoutSHCHE,fora)Heatpumpandb)Overallsystem.
Fig.5showsthevaluesoftheperformancecoef cientoftheheatpump(COP)andoverallsystem(COPS)versustimeofdayforthesystemswithandwithoutSHCHE.AsshowninFig.5,thevaluesoftheCOPforthesystemswithandwithoutSHCHEvaryfrom2.1to2.7andfrom2.4to2.6inJanuary,whiletheychangefrom2.6to3.3andfrom2.7to3.3inFebruary,respectively.Additionally,thevaluesoftheCOPSforthesystemswithandwithoutSHCHEvaryfrom1.9to2.5andfrom2.1to2.3inJanuary,whiletheychangefrom2.4to3.1andfrom2.5to3.1inFebruary,respectively.TheaveragevaluesoftheCOPforthesystemswithandwithoutSHCHEarecalculatedtobe2.31and2.47inJanuary,whiletheyarecalculatedtobe2.73and2.81inFebruary,respectively.TheaveragevaluesoftheCOPSforthesystemswithandwithoutSHCHEarealsocalculatedtobe2.07and2.19inJanuary,whiletheyarecalculatedtobe2.55and2.62inFebruary,respectively.Thevariationsintheinlet-outlettemperaturedifferences(TeaiÀTeao)oftheantifreeze-watersolutiontotheGHEunitwithtimeofdayforthesystemswithandwithoutSHCHEaregiveninFig.6.