Vehicle Testing: Retrofitting Mobile Air Conditioning Systems with HFC-134a

Abstract

This paper explores the use of HFC-134a as the replacement refrigerant for use in retrofitting mobile air conditioning systems. After reviewing the regulatory and market impetus for the work, an overview of some of the experimental work .done using esters with HFC-134a in this application is provided. The London Amendments to the Montreal Protocol, and the Amendments to the U.S. Clean Air Act (Title 6), call for the complete production phase-out of Class One CFCs by the year 2000, with the phase-out schedules including reductions in production. The European Community has called for a more aggressive phase-out schedule, with complete phase-out by the middle of 1997. There are many who expect that when the full parties to the Montreal Protocol re-convene in 1992, they, too, will will adopt this more rigorous schedule. Because of current production phase-out schedules, CFC-12 may be in short supply past about 1995. Estimates at the 1990 Baltimore Conference reported that in the "best case scenario", shortages will occur in late 1996; in the "worse case scenario", these shortages will occur in late 1993 or early 1994. This puts the auto industry in another difficult situationrequired to supply a refrigerant for service which will not be available over the full time needed. In making the transition from CFCs, the mobile air conditioning (MAC) industry decided early that the replacement refrigerant of choice for original equipment was HFC-134a. The reasons for this choice are well known and have been well publicized, and so will not be dwelled upon here.