【正文】 rature, T(8C)Pressure, P(kPa)Specificenthalpy, h(kJ/kg)Specificentropy, s(kJ/kg K)Mass flowrate, ˙m(kg/s)Specificexergy, C(kJ/kg)Exergyrate,˙Ex 188。˙Ii˙FTotRelativeirreversibility:xi188。˙Ii˙PTotExergeticfactor:fi188。 ˙mc(kW)0 – Refrigerant Dead state 1 – – 0 000– Water Dead state 1 – – 0 00 – Moist air Dead state 1 – – – 0 01 Evaporator outlet/pressor inletRefrigerant Super heatedvapor 181 – 2s Condenser inlet/pressor outletRefrigerant Super heatedvapor 1581 – 2a Condenser inlet/pressor outletRefrigerant Super heatedvapor 1581 – 3 Condenser outlet/capillary tube inletRefrigerant Compressedliquid 1580 – 4 Evaporator inlet Refrigerant Mixture 180 – 5 Ground heat exchangerinlet (supply)Brine Liquid 120 – 6 Ground heat exchangercirculating pump inletBrine Liquid 110 – ( 6a Ground heat exchangercirculating pumpoutlet (enteringwater temperature)Brine Liquid 140 – 7 Fan air inlet tothe condenserAir Gas – 8 Fan air outlet fromthe condenserAir Gas – with COPHPand COPsyswere % and %,respectively.. Ground source heat pump system IIThe assumed operating values of the GSHP system II areillustrated in Table 3 in average at design conditions. The m3/hperkWof heating capacity, with a pumping power of W/kWthe closed loop can be categorized as acceptable systems withground was found to be on average kW from Eq. (4).Thiscorrespondsto a peakheat extractionrate of W/m ofboredepth for heating period. The heating average capacity of thewith exergy efficiency values are evaluated in terms of theGSHP unit and the whole system.The exergyefficiency peak values for the GSHP unit and thewhole system on a product/fuel basis are obtained to be %and %, respectively (corresponding to referans statevalue). However, average exergy efficiency of the system isdetermined to be % [8,15].It is obvious from Table 5 that the highest irreversibilityoccurs in subregions I and V for the GSHP unit and the wholesystem, GSHPunitis due to the condenser. This is partly due to the large degree ofsuperheatachievedattheendofthepressionprocess,leadingtolargetemperature differencesassociatedwith the initialphaseO. Ozgener, A. Hepbasli/Energy and Buildings 39 (2020) 66–7574heat pump system was obtained to be kW. Besides this, thevalues for COPHPand COPsyswere estimated to be and, respectively.. Exergetic assessmentIn the exergy calculations, the dead state temperature wastaken to be 1 8C, which is the drybulb temperature (heatingdesigntemperature)%annual cumulativefrequency of occurrence for Izmir [20]. The dead state pressure Paand60%,respectively. Note that state 0 indicates the restricted dead statefor the brine, water and air.. Ground source heat pump system ITemperature, pressure, and mass flow rate data for workingfluid (R22), water and brine are given in Table 4 according totheir state numbers specified in Fig. 1. Exergy rates are alsocalculated for each state, while they are listed in Table 4. Theexergy rate results given in this table indicate that thepressor produces an increase in exergy rate due to itswork input, while all other ponents result in a decrease inexergy rate due to their irreversibilities.Tables 5 and 6 illustrate the values for exergy destructionrate, energy and exergy efficiencies as well as the thermodynamic parameters such as fuel depletion rate, productivityTable 8Exergetic, energetic, and thermodynamics analysis data provided for one representatItem number Component Exergy destructionrate (kW)I Compressor II Condenser III Expansion valve IV Evaporator V Ground heat exchanger VI Circulating pump VII Fancoil unit I–IV GSHP unit I–VII Overall system tubeduetothepressuredropoftherefrigerantpassingthroughit.Besides this, the evaporator has the lowest irreversibility on thebasis of the heat pump cycle.. Ground source heat pump system IITemperature, pressure, and mass flow rate data for workingfluid (R22), water and brine are given in Table 6 according totheir state numbers specified in Fig. 2. Exergy rates are alsocalculated for each state, while they are listed in Table exergyrate results givenin Table 6 indicate that the pressorproduces an increase in exergy rate due to its work input, whileall other ponents result in a decrease in exergy rate due totheir irreversibilities such as in GSHP I.Table 8 illustrates the values for exergy destruction rate,energy and exergy efficiencies, while the thermodynamicparameters such as fuel depletion rate, productivity lack andexergetic factor are included in Table 6. The thermodynamicparameters along with exergy efficiency values are evaluated interms of the GSHP unit and the whole system.The exergyefficiency peak values for the GSHP unit and thewhole system on a product/fuel basis are estimated to be %and %,respectively(correspondingtoreferans statevalue).It is obvious from Table 8 that the highest irreversibilityoccurs in subregions I and V for the GSHP unit and the wholesystem, respectively. The largest irreversibilities in the GSHPunit are due to the evaporator and condenser, respectively. Thisispartlyduetothelargedegreeofsuperheatachievedattheendive unit of the the ground source heat pump (GSHP) system IIUtilizedpower (kW)˙P (kW)˙F (kW) Exergyefficiency (%) of the pression process, leading to large temperaturedifferences associated with the initial phase of heat transfer.The third highest irreversibility is in the presssor. Besidesthis, the expansion valve has the lowest irreversibility on thebasis of the heat pump cycle in GSHP II.5. ConclusionsWe have presented energetic and exergetic aspects of GSHPsystems in general and have