modelingandperformanceevaluationofgroundsourceheatpumpsystems-外文文献(编辑修改稿)

modelingandperformanceevaluationofgroundsourceheatpumpsystems-外文文献(编辑修改稿)内容摘要：

n Eq. (2)can be simplified to flow enthalpies only:X˙minhin188。 X˙mouthout(3)The rate of heat extracted (absorbed) by the unit in theheating mode (the ground heat exchanger load),˙Qeiscalculated from the following equation:˙Qe188。 ˙mwaCp。 wa240。 Tout。 waC0 Tin。 wa222。 (4)The heat rejection rate in the condenser is calculated by:˙Qcond188。 ˙mref240。 h2C0 h3222。 (5)The heat transfer rate in the evaporator is:˙Qevap188。 ˙mref240。 h1C0 h4222。 (6)The work input rate to the pressor is:˙Wp188。 ˙mref240。 h2sC0 h1222。 hi。 phm。 p(7)In case that the mass flow rate on the refrigerant side isnot measured, the space heating load,˙Qsl, may be estimatedas:˙Qsl188。 ˙mairCp。 air240。 Tout。 airC0 Tin。 air222。 (8)˙mair188。 rair˙Vair(9)where ˙mairis the mass flow rate of air, Cp,airis the specific heatof air,˙Vairis the volumetric flow rate of air, r is the density ofair, Tin,airand Tout,airare the average air temperatures enteringand leaving the fancoil units, respectively.The COP of the GSHP can be calculated as:COPHP188。 ˙Qcond˙Wp(10)The coefficient of performance of the overall heatingsystem (COPsys), which is the ratio of the condenser loadto total work consumptions of the pressor, the pumps(brine and water circulation pumps), and the fancoil unit (orthe condenser fan), may be puted by the followingequation:COPsys188。 ˙Qcond(11)Buildings 39 (2020) 66–75 69˙Wp254。 ˙Wpumps254。 ˙WfcThe instantaneous usable energy collected by solar collectorcan be calculated as:˙Q 188。 ˙mwaCp。 wa240。 ToutC0 Tin222。 (12). Exergetic modellingThegeneralexergyratebalancecanbeexpressedasfollows:˙ExheatC0˙Exwork254。 ˙Exmass。 inC0˙Exmass。 out188。 ˙Exdest(13)and more explicitly:XC181 C0T0TkC19˙QkC0˙W 254。 X˙mincinC0X˙moutcout188。 ˙Exdest(14)where˙Qkis the heat transfer rate crossing the boundary attemperature Tkatlocation k,˙Wtheworkrate,ctheflowexergy,h the enthalpy, s the entropy, and the subscript zero indicatesproperties at the restricted dead state of P0and T0.The specific exergy (flow exergy) of refrigerant (or water) isThe exergy rate is calculated by:˙Ex 188。 ˙mc (18)For exergy destruction (or irreversibility), the entropygeneration˙Sgenis calculated first and used in the followingequation:˙I 188。 ˙Exdest188。 T0˙Sgen(19)Theexergydestructionsintheheatexchanger(condenserandevaporator),groundheatexchanger,pump,expansionvalve,andsolar collector are calculated as follows, respectively:C15 Heat exchanger:˙Exdest。 HE188。 X˙ExinC0X˙Exout188。 ˙Exdest(20)C15 Ground heat exchanger:˙Exdest。 grh188。 ˙mwa240。 cinC0 cout222。 254。 ˙QrC181 C0T0TgroundC19(21)O. Ozgener, A. Hepbasli/Energy and Buildings 39 (2020) 66–7570Table 2Benchmarksforgroundcoupledheatpumpsystempumpingefficiencyrequiredpump power to cooling capacity and a parison of the ground source heatpump system I studiedWatts input Performanceper tonne per kW Efficiency GradeBenchmarks for groundcoupled heat pump system [17,18]50 or less 14 or less Efficient systems A: excellent50–75 14–21 Acceptable systems B: good75–100 21–28 C: mediate100–150 28–42 Inefficient systems D: poorGreater than 150 Greater than 42 E: badThe value obtained from the ground source heat pump system I studied Efficient systems Excellentcalculated by:cr。 w188。 240。 h C0 h0222。 C0T0240。 s C0 s0222。 (15)The total flow exergy of air is calculated from [14]:ca188。 240。 Cp。 a254。 vCp。 v222。 T0189。 240。 T=T0222。 C01C0ln240。 T=T0222。 C138254。 240。 1254。 1:6078v222。 RaT0ln240。 P=P0222。 254。 RaT0f240。 1254。 1:6078v222。 ln189。 240。 1254。 1:6078v0222。 =240。 1254。 1:6078v222。 C138254。 1:6078vln240。 v=v0222。 g (16)where the specific humidity ratio is:v 188。 ˙mv˙ma(17)Table 3The assumed operating values of the ground source heat pump system II in averagefor design conditionsaItemSome designed parametersEvaporation/condensation pressures (gage)Evaporating/condensing temperaturesTemperatures of water/antifreeze solution at ground heatexchanger inlet/outletVolumetric flow rates of air/water/antifreeze solutionSoil temperature in depth of 2 mOutdoor air temperatureTemperatures of air at the condenser fan inlet/outletPower input to the pressorPower input to the brine circulating pump/the condenser fanTotal power input to the whole systemHeat extraction rate from the groundHeating load of the room testedHeat extraction rate per meter of horizontal groundheat exchanger lengthHorizontal ground heat exchanger length in m per kW of heatingHeating coefficient of performance of the heat pump unitand whole systemaSome thermodynamic data were taken from [4,13].C03m3/s15 8C0 8C kW kW kW kW kW/m m/kW–C015/42 8CValue UnitC15Pump:˙Exdest。 pump188。 ˙WpumpC0240。 ˙ExoutC0˙Exin222。 (22)C15Expansionvalve:˙Exdest。 valve188。 ˙mref240。 cinC0cout222。 (23)C15Solarcollector:˙Exdest。 col188。 ˙mwa240。 cinC0cout222。 254。 ˙QuC181C0T0TsC19(24)Exergyefficiencyoftheheatexchangers(condenserandevaporator)isdeterminedbytheincreaseintheexergyofthecoldstreamdividedbythedecreaseintheexergyofthehotstreamonaratebasisasfollows:eHE188。 ˙mcold240。 ccold。 outC0ccold。 in222。 ˙mhot240。 chot。 inC0chot。 out222。