States that, based on thermodynamic properties and environmental acceptability, a 30%/70% blend by mass of R32 and R134a was evaluated as a near drop-in alternative to R22 for use in unitary hermetic compressors. Calorimeter data based on ASHRAE and ARI standard test methods were determined and the results interpreted according to ARI standard 540-91. States the results indicate that this blend is as close as can be expected to being a 'drop-in' replacement for R22. Discusses aspects of environmental acceptability as well as those of materials compatibility.

KEYWORDS: Refrigerants, R22, mixtures, R32, R134a, thermodynamics, replacing, hermetic compressors, environment, standards, USA, calorimeters, experiment, testing.