Calculation of the performance of vapour compression heat pumps with solution circuits using the mixture R22-DEGDME

In this paper the results of performance calculations of two vapour compression heat pump cycles, one with a single-stage solution circuit and one with a two-stage solution circuit, are presented. As a working fluid combination R22-DEGDME was selected out of a number of candidates in order to employ a safe and non-toxic mixture. It was found that both cycles show a significant increase in coefficient of performance (COP) (up to 50% for the two-stage cycle) compared to R22. The two-stage cycle shows a pressure ratio which is only 45% that for pure R22, resulting in increased mass flow rate but reduced capacity.