Experimental Analysis of Mass Composition of R417A in Presence of Leak/Recharge in a Heat Pump Water Heater

摘要

As a substitute for R22, an environmentally friendly zeotropic mixture R417A is often employed. The large glide temperature of the zeotropic mixture R417A could cause capacity and efficiency reductions due to changes in its composition after an isothermal vapor leak/recharge process. It is, therefore, necessary to predict the composition change in R417A under all leak conditions. This paper presents the experimental analysis of the mass composition of R417A in the presence of a 0-50% isothermal vapor leak/recharge in a heat pump water heater. Based on the experimental data, a simple model is proposed to describe the composition change in R417A for various leaks and recharge scenarios. The effect of composition change in the performance of a heat pump water heater is also dealt with. Experimental results show that the composition changes in R417A increase as ambient temperature decreases. Isothermal vapor leaks have a great effect on the composition of R417A and the performance of a heat pump water heater at lower temperatures. It is also found that when the ambient temperature is higher than 7℃ with a 10% leak and R417A recharge, there is almost no difference in the performance of the plant with respect to the original state except that the compressor discharge temperature is lower.