Effects of different ambient temperatures on performance of electric vehicles' heat pump air conditioning

A heat pump air conditioning experimental system for electric vehicles based on the vapor-compression cycle was designed because much energy was consumed for the electric vehicle air conditioning under the heating mode when the ambient temperature was low. The refrigerant temperature and pressure in the high-pressure pipeline, the rate of temperature rising in the cab and the coefficient of performance (COP) for the air conditioning system were studied in the heating mode under different ambient temperatures and different compressor speeds. The test results indicate that, when the ambient temperature and the compressor speeds are higher, the temperature and pressure of the refrigerant at the compressor outlet and the heat exchanger outlet are higher, and the average temperature increases faster and the time reached to the comfort temperature is shorter in the cab. When the ambient temperature is higher in case that the compressor kept the same speed, the COP is greater.