Seite - 352 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2016,9, 240 Figure7.Airconditioningsystemstructureandoperationforelectricvehicles [47]. With the twoheat exchangers in the interiorunit, the systemcouldnot onlyprovide cooling, heatinganddemisting/dehumidifying,butalsoensuresafedrivingwhentheoperationmodewas switched fromcooling toheating. Subsequently, Xie andMin et al. measured theperformanceof this representativeheatpumpACsystem[64,65]. In [66], an internalheatexchangerwas installed in anautomobileACsystemto improvesystemperformance. In [67,68],asuction lineheatexchanger was added to a car AC system. The results showed that both the capacity and the COP could be improved by up to 25%, while the compressor discharge temperatures were also increased. Furthermore,Ahn et al. [69] comparedtheperformanceof theAC,heatpumpanddual-evaporator heat pump systems, whichwere all combinedwith a heater. The experimental results showed that the dual-evaporator heat pump system as shown in Figure 8, had a superior performance in the dehumidifying andheating operation comparedwith the other two systems. The specific moistureextractionrateandCOPof thedual-evaporatorheatpumpsystemwere53%and62%higher, respectively, than thoseof theheat pumpsystemat the indoor airwet bulb temperature of 13 ˝C. Moreover, the specificmoisture extraction rate andCOPof theheatpumpsystemwere154%and 180%higher, respectively, thantheACsystemat the indoorairwetbulb temperatureof15˝C. ȱ Figure8.Schematicdiagramof thedual-evaporatorheatpumpsystemforelectricvehicles [69]. 352