Presents results obtained from an experimental programme where R32/R134a and R32/R152a blends were tested in a two-ton split-system air conditioner. The objectives of this project were to demonstrate through "drop-in" system tests that a viable set of refrigerant alternatives to R22 exists and to identify the hardware modifications necessary to obtain optimal performance levels using the alternatives. Five different refrigerant blends of R32 with R134a and R152a were tested as "drop-in" refrigerants against a set of R22 baseline tests for comparison. Other than the use of a different lubricant and a hand-operated expansion valve, no form of optimisation was performed for the new refrigerant blends. While the tests showed that compared to R22, the R32/R134a blends performed to within 2% of efficiency with comparable capacity, it is expected that with proper system optimisation for the new refrigerant blends, such as optimal charge, temperature glide, superheat/subcooling, and expansion device, performance levels better than those of R22 should be possible.

KEYWORDS: testing, refrigerants, R22, unit air conditioners, R32, R134a, R152a, performance, optimisation, comparing, mixtures.