Recent Development in the Design of New Refrigerant Mixtures for Existing Future Systems

摘要

The primary approach industry has taken to fill the void resulting from the elimination of the most important CFC's (i.e., CFC-11 and CFC-12) has been to develop other single component refrigerants (i.e., HCFC-123 and HFC-134a) which have very low or zero ozone depletion potential. These alternatives were attractive mostly because they had similar pressure-temperature property profiles relative to that which they were replacing and, this, requred minimal machinery design changes for adoption. No such single component alternative has been discovered for HCFC-22 or CFC-502. As a result, the industry, with its needs to meet the various phase out dates internationally agreed upon, has begun an intensive effort to tailor various zeotopres (a.k.a. nonazeotropes) and, whenever possible, azeotropes to act as 'drop-in' alternatives in exsiting equipment as well as the long term working fluids for new equipment.