热气旁通技术在纯电动客车热泵低温制热中的应用

Application of hot gas bypass to heat pump heating at low temperature for electric bus

通过将热气旁通装置加装在纯电动客车热泵上,并在低温工况(室外-15℃/室内-5℃)下进行了制热性能试验研究,得出:制热量、功率、排气温度及出风温度等系统参数均随热气旁通装置阀开度的增大而下降,该装置在一定范围内可避免低压过低引起的压机频繁启停或者低压保护停机,可使纯电动客车热泵在较低温环境中依然可以稳定运行制热,扩大热泵系统的工作范围。此外,还提出了热气旁通装置的初步控制方法。

A set of hot gas bypass was installed in the electric bus heat pumpfor experimental research at low temperature,especially at the outdoor temperature-15 ℃ and indoor temperature-5 ℃.It was found that the system parameters such as heating capacity,power,discharge temperature and supply air temperature all decrease with the increasing of the valve opening of the hot gas bypass device.The frequent start-stop or shutdown result from low pressure of the heat pump was avoided by the device in the low temperatureenvironment.As a consequence,The heat pump could runcontinuously at low temperature,thus its operation range was enlarged.The controlmethod of thedevice was put forward.