3695 -- Near-Azeotropic Refrigerant Mixtures as Potential Drop-In Substitutes for R-502 PDF

Describes a series of tests comparing the drop-in system performance of R502 with two near-azeotropic refrigerant mixtures. The tests were conducted over a suitable range of evaporating temperatures using condensing mixtures, superheat and subcooling conditions for low-temperature refrigeration systems. The mixture investigated are R22/FC218/HC290 (55%/39%/16%) with an approximately 8% to 10% greater evaporator capacity than R502, and a 74%/20%/16% mixture with approximately the same evaporator capacity as R502 at low evaporating temperatures, with capacity increasing by up to approximately 12% relative to R502 at higher evaporating temperatures. Presents a schematic of the test facility, supplies the test measurements and analyses them. Concludes in summary that the mixtures offer environmentally acceptable alternatives to R502 and can provide satisfactory thermodynamic performance as near-term system drop-in replacements.

KEYWORDS: Testing, refrigerants, R502, mixtures, comparing, replacing, performance, thermodynamics.