Steady state and start-up performance characteristics of air source heat pump for cabin heating in an electric passenger vehicle

• Many EVs suffer from a short driving range and shortage of cabin heating.
• The advanced air source heat pump system for cabin heating was investigated under various experimental conditions.
• The observed heating and capacity were 3.26 and 3.10 kW at an outdoor temperature of −10 °C.
• However, the observed transient performance of the considered system could be inferior to cabin heating load of electric passenger vehicles.
• Therefore, the suggested hybrid heating method under −10.0 °C could provide better thermal comfort.

The heating COP and capacity for evaluating the steady state performance and the transient temperature for evaluating the cabin heating performance of an automotive air source heat pump system were investigated under various experimental conditions for an electric vehicle. To optimize refrigerant charge amount of tested heat pump system, the system was investigated under cooling modes and it was determined by 650 g. The optimum EEV openings of heating modes were suggested with reasonable super-heating and heating capacity along with the ambient temperature. The heating COP and capacity were 3.26 and 3.10 kW at an outdoor temperature of −10 °C. The observed heating and transient performance of the automotive air source heat pump system mean it could be inferior to cabin heating load of electric passenger vehicles. Therefore, a hybrid heating method was suggested as a possible option for realization of longer driving ranges and thermal comfort for passengers.