Evaluation of Fluorocarbon Blends as Automotive Air Conditioning Refrigerants

A search for replacements for CFC-12 in automotive air conditioning has led to the discovery of near azeotropelike ternary blends of HCFC-22, HFC-152a, and CFC-114 or HCFC-124. Ozone depletion potential is reduced to 0.42 with the blend containing CFC-U4, and to 0.03 with the blend containing HCFC-124. The blends provide automotive cooling performance slightly better than CFC-12, have good oil/refrigerant/metals stability, and will not become flammable during hose permeation or vapor leaks. Based on initial tests, the blends appear to be viable CFC-12 replacements for vehicles equipped with nylon lined refrigerant hoses, alkylbenzene oil as compressor lubricant, and possibly molecular sieve desiccant of three Angstrom pore size.