Abstract： Based on the experimental data and the first and second law of thermodynamics, outside air temperature and compressor speed, the coefficient of performance (COP) and exergy destruction and exergy efficiency of an electric vehicle heat pump system were deduced by changing conditions involving refrigerant (R134a) charge. The results show that the optimum refrigerant charge is at 400 g. The exergy destruction is within a range of 0.61-1.28 kW. The condenser and the evaporator has a relatively lower exergy efficiency (37.9%-53.1% for condenser and 34.2%-61.8% for evaporator, respectively).
Key words： electric vehicle heat pump system (EVHPS); refrigerant charge; variable conditions; exergy performance