To improve the thermal management performance and solve the refrigerant carbon emissions issue of electric vehicle, this article proposed a transcritical CO₂ heat pump air conditioning system suitable for electric vehicle with natural CO₂ as refrigerant, and performance analysis was conducted. The results show that: this system can still ensure a heating capacity of 5 kW and 36 ℃ at the outlet in an environment of -20 ℃. As the compressor speed increases, the heating capacity increases, but Coefficient Of Performance (COP) decreases. The appropriate increment in the air volume of the internal gas cooler can effectively increase the heating capacity and COP, but excessive air volume will lead to low outlet air temperature, which is not conducive to heating. At ambient temperature of 40 ℃ and compressor speed of 7 000 r/min, the cooling capacity is 4.2 kW and the COP is 1.1. As the air volume of the internal evaporator increases, the cooling capacity and COP increase, indicating that the appropriate increment in air volume can effectively improve cooling performance.

Electric vehicle  /  Transcritical CO₂ heat pump air conditioning system  /  Performance analysis