A method has been developed to examine the effect of different mixture pairs and compositions on heat pump cycle performance parameters and on relative component sizing. In modelling the heat pump, it was assumed that the temperature limits of the source and sink fluids were known. In addition, a minimum "pinch" temperature was set for the heat exchangers. Mixtures of R22/R11 and R22/R114 have been examined. When a water-source heat pump was modelled, a working fluid of R22/R114 showed a cycle efficiency improvement of 34% over pure R22, and R22/R11 showed a 26% improvement. Cycle heating capacities, pressure ratios, component irreversibilities, temperature distributions, and relative UA values for the heat exchangers are also presented.

KEYWORDS: heat pumps, performance, calculating, mixtures, R22, R11, R114, cyclic, pressure, temperature distribution, heat exchangers, non azeotropic, refrigerants.