In this study an air conditioning system with an ejector is proposed for electric vehicles. The indoor evaporator is designed as a separate front and rear evaporator. An ejector is added between the front and rear evaporators to increase the suction pressure of the compressor

and to form a stepped evaporation in the front and rear evaporators to optimize the performance of the system. The performance of the air conditioning system with an ejector for an electric vehicle was studied experimentally under different evaporation and condensation temperatures

and was compared with that of the traditional air conditioning system for electric vehicles. The experimental results indicated that the performance of the air conditioning system with an ejector for an electric vehicle is always better than that of a traditional air conditioning system under different refrigeration conditions. The performance improvement of the air conditioning system with an ejector gradually increases with an increase in the evaporation temperature or a decrease in the condensation temperature. In the range of the experimental conditions

the refrigeration capacity of the air conditioning system with an ejector increased by approximately 11.10%–14.57%

and the coefficient of performance (COP) increased by approximately 13.09%–16.61% compared with the traditional air conditioning system for electric vehicles. It was found in experiments that the heat transfer of the rear evaporator only accounts for 10.93%–13.51% of the system refrigeration capacity

and its heat transfer potential is not fully released. The flow rate of the refrigerant in the rear evaporator can be increased by adjusting the length of the capillary tube and improving the entrainment ratio of the ejector to further improve the COP of the system.