A typical three-ton air-to-air heat pump was tested with the baseline refrigerant R22 (an HCFC) and zero ODP alternative HFC refrigerants. The results of these system tests are presented. The heat pump was run with an azeotropic mixture (ASI 1990) of R32/125 (60%/40%) and a zeotropic blend of R32/125/134a (30%/10%/60%), as well as the baseline fluid, R22. The results of the tests showed a significant increase in efficiency of 8% to 9% for the R32/125 azeotrope and a slight decrease of 1% to 2% for the ternary blend (R32/125/134a) compared to the baseline fluid.

KEYWORDS: air air heat pumps, testing, refrigerants, R22, heat pumps, azeotropic, mixtures, R32, R125, R134a.