过冷度对R245fa热泵系统性能影响的实验研究
Experimental research on influence of subcooling degree on performance of heat pump systems with R245fa as refrigerant
摘要：
对以R245fa为制冷剂的中高温热泵在不同过冷度下进行了不同蒸发温度和冷凝温度对系统性能影响的理论分析和实验研究。对给定节流后干度和蒸发温度时不同冷凝温度和过冷度下制热性能系数和制热量的实验值与理论值进行了对比分析。结果表明：蒸发温度为45 ℃、冷凝温度为75～90 ℃时，过冷度每增大2 ℃，制热量增大约1.0%～3.3%，制热性能系数增大约0.3%～6.5%；节流后干度为0.15和蒸发温度为45 ℃时，冷凝温度从65 ℃升高到95 ℃，制热量增大约8.86%，过冷段制热量占比从3.4%增大到22.5%。在较高冷凝温度下，适当增大过冷度能明显提高系统性能。
Abstract：
The theoretical analysis and experimental research on the effect of different evaporation and condensation temperatures on the performance of the medium and high temperature heat pumps with R245fa as the refrigerant under different subcooling degrees are carried out. The experimental and theoretical values of the heating performance coefficient and heating capacity under different condensation temperatures and subcooling degrees are compared and analysed when the dryness after throttling and the evaporation temperature are given. The results show that when the evaporation temperature is 45 ℃ and the condensation temperature is 75 to 90 ℃, the heating capacity increases by about 1.0% to 3.3%, and the heating performance coefficient increases by about 0.3% to 6.5% for every 2 ℃ increase in the subcooling degree. When the dryness after throttling is 0.15 and the evaporation temperature is 45 ℃, the condensation temperature increases from 65 ℃ to 95 ℃, the heating capacity increases by about 8.86%, and the proportion of heat generated in the subcooling section increases from 3.4% to 22.5%. At higher condensing temperatures, appropriately increasing the subcooling degree can significantly improve the system performance.
Keywords:mediumandhightemperatureheatpump;subcoolingdegree;R245fa;heatingperformancecoefficient;heatingcapacity;evaporationtemperature;condensationtemperature;dryness