电动汽车热泵空调复合除霜特性的实验研究

摘要

To solve the problem that frosting leads to lower efficiency of the heat pump air conditioner for electric vehicle in the heating process, a new method of composite defrosting is proposed after analyzing the deficiency of the existing defrosting method. At the beginning of the defrosting, firstlyenter the bypass defrost stage. Then reverse cycle defrost stagetimelyaccording to the defrost state. An electric bus air conditioning system with a rated power 8. 0 kW was transformed,and the comparative test was carried out in the simulated environment of the outdoor at (2 ± 0. 5) ℃, the indoor at (20 ± 0. 5) ℃ and the relative humidity of (80 ± 5)%. The change of the compressor suc-tion and discharge pressure, the outdoor heat exchanger temperature, indoor temperature and power consumption were measured. The ex-perimental results indicated that, compared with the method of reverse cycle defrosting, the compressor shock of discharge and suction was reduced, the fluctuation of indoor temperature was decreased and energy consumption decreased by 8. 13%;compared with the method of hot-gas bypass defrosting, the time of defrosting was decreased by 60 s and energy consumption decreased by 6. 56%.%为了解决电动汽车热泵空调在制热过程中结霜导致制热效率降低的问题，本文在现有除霜方法所存在的缺陷的基础上，提出了电动汽车热泵空调复合除霜方法，所谓复合除霜方法就是在除霜开始后，首先进入旁通除霜阶段，然后根据除霜状态，适时进入逆循环除霜阶段。本文对一台额定功率8.0 kW的电动客车空调进行改造，并在室外环境温度（2±0.5）℃，相对湿度（80±5）％，车内温度为（20±0.5）℃的模拟环境条件下进行对比实验，测量压缩机吸排气压力、室外换热器温度、室内温度与消耗功率随时间的变化。结果表明：与逆循环除霜相比，复合除霜压缩机吸、排气压力冲击减小，室内温度波动减小，能耗降低8.13％；与旁通除霜方法相比，除霜时间减少60 s，能耗降低6.56％。