Choosing the Right Refrigerant

The driving forces in refrigerant development and selection are varied and sometimes conflicting; however, several options are currently available that consider all aspects of the refrigeration system. There are five major factors that design engineers must consider in selecting a refrigerant for a particular application: performance, safety, reliability, environmental acceptability, and simple economics. The reliability of a refrigeration system depends to a large extent on the chemical stability of the refrigerant and its compatibility with the various system components and the compressor lubricant. Among several groups of alternatives, two—the hydrochlorofluorocarbons (HCFCs) and the hydrofluorocarbons (HFCs)—are the most useful. One of the major challenges in identifying halocarbon alternatives to ozone-depleting substances is to strike a balance between the various affecting factors. In the United States, there is considerable resistance to use of hydrocarbons or ammonia in applications that use halocarbons. This is due to liability concerns arising from their flammability and, in the case of ammonia, also toxicity.