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Experimental Evaluation of the Flammability and Performance Potentials of Two Azeotropic Refrigerant Mixtures.


pdf icon Experimental Evaluation of the Flammability and Performance Potentials of Two Azeotropic Refrigerant Mixtures. (3457 K)
Kim, M. S.; Mulroy, W. J.; Didion, D. A.

Korean Society of Mechanical Engineers. Symposium on Transport Phenomena (ISTP-6) in Thermal Engineering, 6th International. Volume 3. May 9-13, 1993, Seoul, Korea, Lee, J. S.; Chung, S. H.; Kim, K. H., Editor(s)(s), 153-158 pp, 1993.

Keywords:

refrigerants; evaluation; flammability; heat pumps; mixtures

Abstract:

The phaseout of CFC and HCFC refrigerants requies determination of substitute refrigerants for use in domestic heat pumps and refrigerators. This paper presents both flammability and heat pump performance test results of two azeotropic refrigerant mixtures of R-134a (1,1,1,2-tetrafluoroethane) with R-290 (Propane) and R-600a (Isobutane): R-290/134a (45/55), R-134a/600a (80/20). The flammability limit of R-290/134a is found as 2.9-11.0% by volume. And that of R-134a/600a is 3.9-13.3% by volume. Although the azeotropic mixtures remain flammable, they are less than their pure hydrocarbon components. The performance characteristics are compared with pure R-12, R-22, R-134a, and R-290 at test conditions including cases using liquid-line/suction-line heat exchange. In most cases, the coefficients of performance of the azeotropic mixtures are higher than that of R-12 and R-134a. In every case, the capacity for R-290/134a is higher than that for R-22. Also, the system capacity for R-134a/600a is higher than that for R-12 and R-134a. Results show that the discharge temperature for the azeotropic mixtures is always lower than that for the other refrigerants.