The impact of refrigerant properties on flow distribution was theoretically analyzed in this paper. Since the difference between gas and liquid phase on the density and viscosity of R290 is smaller than that of R22, R290 has theoretically a better flow distribution performance and smaller pressure-drop than R22. And with the increase of evaporating temperature, flow distribution performance of both refrigerants became better. According to the experimental study on two path arrangement samples of microchannel heat exchanger, R290 and R22 had close flow distribution performances, and R22 was better in 2-path sample, R290 was better in 4-path sample. Increasing the flow path from 2 to 4, flow distribution became better, the heat transfer of evaporator increased by 5%-6%, the heating capacity increased by 1.8%, and COP increased by 8%-10%. R290 showed a better flow distribution performance and had a bigger increase of heat transfer. Moreover R290 had smaller increase of pressure-drop. It is more suitable to multi-path heat transfer exchanger, to get more increase of COP.% 本文从理论上比较分析了制冷剂物性对于分配性能的影响,R290汽液两相的粘度和密度差别相比R22较小,流量分配特性理论上略好,制冷剂压降也更小.且随着蒸发温度的升高,流量分配特性会变好.通过在两种流程微通道换热器中的对比实验,发现R22和R290在四流程中的分配特性明显好于两流程,蒸发器换热器量提升5%~6%,系统制热量提高1.8%左右,COP提高8%~10%.由于R290分液特性略好,R290的换热量提高幅度略大于R22,且由于R290压降增加更小,更适合于多流程换热器,使得系统COP提升更多.
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