Experimental research on influence of subcooling degree on performance of heat pump systems with R245fa as refrigerant

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.