A methodology for selecting and screening novel refrigerants for use as alternative working fluids

Ratification of the Montreal Protocol and similar international agreements on the fully halogenated CFCs and halons has intensified the efforts of industry and some government agencies to phase out certain refrigerants connected to ozone depletion. Identification and testing of substitute refrigerants has understandably become a top priority to the air-conditioning and refrigeration industry. A selection and screening process of alternative working fluids has been developed and is described herein. These criteria are presented to satisfy the need for a comprehensive approach in selecting alternative refrigerants and for determining their preliminary acceptability. The proposed guidelines are based on the candidate refrigerant's thermophysical properties, operating pressures, capacity, compatibility with specific components of a refrigeration system, and safety performance with special attention given to mixtures. Analytical studies and experimentation of selected compounds will be required ar a later stage to assess the theoretical performance of substitute refrigerants and collect critical performance data.