Experimental comparison of heat pump performance using CO2 or R134a as a refrigerant for electrical vehicles.

This paper experimentally evaluates the cooling and heating performance of CO2 and R134a heat pump systems applied in electrical vehicles. A mobile scroll type electrical compressor with 27 cc displacement was used for R134a system, and a commercial rotary type electrical compressor with 6 cc displacement was adopted for CO2 prototype system. Comparative experiments were carried out for these two systems in the calorimeter test facility. In addition, the effects of compressor speed, outdoor air temperature, outdoor air velocity and indoor air inlet temperature on system performance were also investigated. Experimental results concluded that CO2 system achieves comparable cooling capacity with R134a system, and performs a high heating COP and heating capacity in a cold climate. The advantage of CO2 heating performance will contribute to extending the driving range of electrical vehicles in a cold climate and making CO2 refrigerant more promising in the field of automobile air conditioner.

本文通过实验评估了应用于电动汽车的CO₂与R134a热泵系统的制冷及制热性能。R134a系统采用排量为27 cc的移动式涡旋式电动压缩机，而CO₂原型系统则选用排量为6 cc的商用旋转式电动压缩机。在量热计测试装置中对这两种系统开展了对比实验。此外，还探究了压缩机转速、室外空气温度、室外空气流速及室内空气入口温度对系统性能的影响。实验结果表明，CO₂系统的制冷量与R134a系统相当，且在寒冷气候下具有较高的制热COP（Coefficient of Performance，性能系数）及制热量。CO₂系统的制热性能优势有助于延长电动汽车在寒冷气候下的续航里程，并使CO₂制冷剂在汽车空调领域更具应用前景。