I found a study addressing R290 & R1270 as a replacement for R22,
HERE
They both compare very favorably.
Here is the abstract:
Quote:
Abstract
In this study, therma l performance of two hydrocarbon refrigerants of R290 and R1270 was measured in an attempt to substitute R22. They were tested in a heat pump bench tester of 1 ton capacity with a hermetic rotary compressor. Water and water/glycol mixture were employed as the secondary heat transfer fluids in the test bench. All tests were conducted under the same external conditions simulating three different air-conditioning and heat pumping conditions. Test results show that the coefficient of performance of these hydrocarbon refrigerants is up to 11.5% higher than that of R22 under all conditions. Refrigeration capacity of R290 is up to 8.2% lower than that of R22 under normal air-conditioning and heat pumping conditions. Under extremely cold temperature conditions, however, the capacity of R290 is 5% higher than that of R22. On the other hand, the capacity of R1270 is similar to that of R22 under all conditions. Compressor discharge temperatures of these hydrocarbons are reduced by 14–31°C as compared to R22. The amount of charge is reduced up to 58% as compared to R22. Overall, these hydrocarbons provide good performance with reasonable energy savings without any environmental problems and thus can be used as long-term alternatives for residential air-conditioning and heat pumping applications.
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And
HERE is a report on the successful use of R1270 in the food industry.
I think dc€x has a point here... R1270
should also be considered.
Best,
-AC