NIST Time|NIST Home|About NIST|Contact NIST

HomeAll Years:AuthorKeywordTitle2005-2010:AuthorKeywordTitle

Application of HFCs as Refrigerants.

pdf icon Application of HFCs as Refrigerants. (2051 K)
Didion, D. A.

International Congress of Refrigeration, 20th Proceedings. September 19-24, 1999, Sydney, Australia, [pages unknown] pp, 1999.


refrigerants; hydrofluorocarbons; azeotropic; toxicity; zeotropic; flammability


The technical criteria for using hydrofluorocarbons (HFCs), as refrigerants in the vapor compression cycle, is presented. If thermodynamic performance is to be optimized, particular attention must be paid to the fluid's critical point and molar heat capacity. A reasonable balance between volumetric capacity, which implies equipment size, and coefficient of performance is best achieved by selecting a refrigerant of appropriate vapor pressure. To achieve these balances for the many different applications, both azeotropic and zeotropic mixtures of HFCs are now in use. The characteristics and performance advantages and disadvantages of these mixtures are discussed. Additional physical properties of these refrigerants dealing with lubricant compatibility and safety considerations, i.e. toxicity and flammability, also are discussed.