Performance of R502 Alternative Refrigerants for Low Temperature Applications

In this study, 2 pure hydrocarbon refrigerants of R1270 (Propylene) and R290 (Propane) and 3 binary mixtures composed of R1270, R29O and R152a were tested in a refrigerating bench tester with a scroll compressor in an attempt to substitute R502 used in most of the low temperature applications. The test bench provided kW capacity and water and water/glycol mixture were employed as the secondary heat transfer fluids. All tests were conducted under the same external conditions resulting in the average saturation temperatures of -28 and in the evaporator and condenser, respectively. Test results showed that all refrigerants tested had higher capacity and higher COP than R502. The compressor discharge temperature of R1270 was similar to that of R502 while those of all other refrigerants were lower than that of R502. For all alternative refrigerants, the amount of charge was reduced up to as compared to R502. Overall, these alternative refrigerants offer better system performance and reliability than R502 and can be used as long term substitutes for R502 due to their excellent environmental properties.