冷却水流量对CO_2空气源热泵气体冷却器换热性能影响的实验研究

Experimental study on the effect of cooling water flow on heat transfer performance of CO_2 air source heat pump gas cooler

以CO_2为工质,对空气源热泵热水器矩形螺旋套管气体冷却器的换热特性进行实验研究,搭建了空气源热泵热水器实验台,测试分析冷却水流量的变化对冷却水进出口温差、CO_2进出口压力与温度、CO_2质量流量、气体冷却器总换热量、总传热系数及热泵系统COP等参数的影响,探究其对气体冷却器换热性能的变化规律。结果表明:随着冷却水流量的增加,冷却水进出口温差、CO_2进出口压力和温度均呈下降趋势,CO_2质量流量则呈上升趋势;气体冷却器的总换热量增加49.70%,总传热系数增加57.55%,COP增加73.41%,增幅较大;而气体冷却器换热效能系数仅增加1.77%,变化趋势不明显。

The heat transfer characteristics of rectangular spiral gas cooler in the air source heat pump water heater were studied experimentally with R744 as working fluid. In order to explore the influence of cooling water flow rate on the heat transfer performance of the gas cooler, the temperature difference between inlet and outlet of cooling water, the pressure of CO2 inlet and outlet, the temperature of CO2 inlet and outlet, the mass flow rate of CO2, the total heat exchange amount of the gas cooler, the total heat transfer coefficient of the gas cooler, the effectiveness of heat exchanger and the COP of the heat pump system were tested and analyzed. The experimental results show that with the increase of cooling water flow, the temperature difference between inlet and outlet of cooling water, the inlet and outlet pressure of CO2 and the inlet and outlet temperature of CO2 both decrease, and the mass flow rate of CO2 increases. While the effectiveness of heat exchanger increases by only 1.77%, and the change trend is not obvious.