Blends of refrigerant fluids have been developed as improved alternatives to conventional chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) refrigerants, which contribute to depletion of stratosphere ozone. Each blend of this type is a zeotropic or nearly azeotropic mixture of trifluoroiodo-methane (CF3I) with two or three hydro-fluorocarbon (HFC) refrigerant compounds. In addition to having zero ozone-depletion potential, these CF3I-containing refrigerant blends are nonflammable, and have low toxicity, low global-warming potential (GWP), and low total equivalent warming impact (TEWI). [GWP and TEWI are two measures that quantify different aspects of contributions to global warming.]
In comparison with prior non-CFC and non-HCFC refrigerants (including blends) that do not contain CF3I, the present improved refrigerant blends containing CF3I offer greater energy efficiencies and smaller temperature glides. (The temperature glide of a zeotrope is the range of temperatures over which the zeotrope and its constituents evaporate and condense as the proportions of the constituents vary.) Some of the improved refrigerant blends can be substituted directly for older medium- and high-pressure refrigerants, without need to modify refrigeration equipment. The older refrigerants in question are R-12 (dichlorodifluoro-methane), R-22 (chlorodifluoromethane), R-134a (tetrafluoroethane), and R-502 (a blend of chlorodifluoromethane and chloropentafluoroethane).
This work was done by Jonathan S. Nimitz, Edward T. McCullough, and Patrick M. Dhooge of Nimitz, Inc., for Kennedy Space Center.
In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to
Dr. Patrick Dhooge
4500 Hawkins Street NE
Tel No: (505) 341-0893
Refer to KSC-12180, volume and number of this NASA Tech Briefs issue, and the page number.