电动汽车热泵空调系统热气旁通除霜的试验研究

Experimental study on defrosting of electric vehicle heat pump air conditioning system by hot gas bypass

针对电动汽车热泵系统室外换热器结霜会使系统性能严重衰减且不稳定性加剧等问题,在研究目前汽车上普遍使用的逆循环除霜模式的基础上,设计并搭建了应用于电动汽车的热气旁通除霜系统,试验研究了两种模式在不同环境工况下的除霜性能,分析了两种除霜模式的运行特性,并估算了两种除霜模式下的电动汽车续航里程。结果表明:在5~-5℃的环境工况下,逆循环除霜用时80~400 s,除霜过程平均功耗618~1008 W;热气旁通除霜用时350~600 s,系统功耗1383~1621 W。相比于逆循环除霜,热气旁通除霜用时增加200~270 s,功耗上升613~765 W,续航里程减少1.9%~3.8%,但在除霜过程中有利于保证乘员舱内的舒适性。在室外环境温度低于0℃时,除霜过程中关闭室外换热器风机,能减小空气侧换热损失,提高除霜效率。

In view of the problem that outdoor heat exchanger frosting of electric vehicle heat pump system will seriously degrade the system performance and increase the instability,based on the study of the reverse cycle defrosting mode commonly used in automobiles,a hot gas bypass defrosting system was designed and built.The defrosting performance of the two modes under different environmental conditions was experimentally studied,and the operation characteristics of the two defrosting modes were analyzed,and the range of electric vehicle under two defrosting modes was estimated by theoretical derivation.The results show that,at 5~-5℃ambient temperature,the reverse cycle defrosting time is 80~400 s,and the average power consumption during the defrosting is 618~1008 W.The hot gas bypass defrosting takes 350~600 s,and the average power consumption is 1383~1621 W.Compared with the reverse cycle defrosting,the hot gas bypass defrosting time increases by 200~270 s,the power consumption increases by 613~765 W,and the range decreases by 1.9%~3.8%.However,it is beneficial to ensure the comfort in the cabin during the defrosting process.When the ambient temperature is below 0℃,closing the outdoor heat exchanger fan during the defrosting process can reduce the air side heat transfer loss and improve the defrosting efficiency.