Near Azeotrope Refrigerants to Replace R502 in Commercial Refrigeration

The Refrigerant RS02, an azeotrope of CFCllS and HCFC22, is an important refrigerant in commercial refrigeration, especially for low temperature applications using single stage compressors. current users of R502 are faced with an earlier than ~nticipated phase-out and are under great pressure to find suitable alternates for retrofit and o.E.M. (new) applications. Single components like HCFC12S, HFC143a, and HFC32 are not viable candidates, Some candidates which are being evaluated are near azeotropes containing HCFC22 and propane as components. This paper discusses the challenges involving the near azeotropes and also includes status on lubricants and materials compatibility requirements. The final solution for R502 involves finding a suitable zero ozone depletion potential refrigerant candidate with an appropriate lubricant.