The primary approach industry has taken to fill the void resulting from the elimination of the most important CFCs (i.e., R11 and R12) 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 profiles relative to that which they were replacing and, thus, required minimal machinery design changes for adoption.
Bulletin of International Institute of Refrigeration
Role of Refrigerant Mixtures, Bulletin of International Institute of Refrigeration, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=910541
(Accessed December 2, 2023)