摘要
针对电动汽车热泵空调系统在冬季运行时室外换热器易结霜而影响系统制热性能的问题,本文设计搭建实验系统并进行研究,分析了多流程微通道换热器的结霜特性。实验结果表明:室外换热器表面霜层生长和表面温度下降两个因素之间为联动关系,各流道霜层分布呈不均匀状态,换热器内两相制冷剂密度不同且受重力影响,导致产生气液相分离和在流道内分布不均的状况。另外,室外换热器表面霜覆盖率的增长会导致室外换热器制冷剂侧的温度、压缩机吸排气压力、制热量等降低,引起导致压缩机单位功耗增加,以环境温度为0℃的数据为例,当霜覆盖率达77.4%时,吸气压力、排气压力和制热量的降幅分别为33.4%、12.1%和25.8%,单位功耗增幅为32.0%,导致系统运行的稳定性降低,使制热量无法满足乘员舱制热需求。
Exterior heat exchangers of heat pumps in electric vehicles are prone to frost when operated in winter.This project experimentally investigated this phenomenon.A relationship between frost growth and reductions in the surface temperature of the external heat exchanger was demonstrated.Furthermore,the distribution of frost on each flow channel was uneven,reflecting the different refrigerant densities of gaseous and liquid phases within the channel and the influence of gravity,which leads to a separation and uneven distribution of the two-phase refrigerant in the flow channel.In addition,the increase of frost on the exterior heat exchanger will result in decreased refrigerant temperature within the exterior heat exchanger,and decreased suction and discharge pressures of the compressor and heating capacity,while causing an increased unit power consumption of the compressor.With an ambient temperature of 0℃,when the rate of frost coverage reaches 77.4%,the reduction of suction pressure,discharge pressure,and heating capacity were 33.4%,12.1%,and 25.8%,respectively.Further,the increase of unit power consumption was 32.0%,which reduced the stability of operation and led to an unacceptable level of heating.
作者
包佳倩
苏林
刘明康
方奕栋
李康
Bao Jiaqian;Su Lin;Liu Mingkang;Fang Yidong;Li Kang(School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, China)
出处
《制冷学报》
CAS
CSCD
北大核心
2020年第3期58-64,共7页
Journal of Refrigeration
关键词
汽车空调
热泵
结霜特性
微通道换热器
automotive air-conditioning
heat pump
frosting characteristics
microchannel heat exchanger
