R407C

R-407C is a hydrofluorocarbon refrigerant used primarily in air conditioning and heat pump systems as a replacement for R-22. It is a zeotropic blend consisting of approximately 23% R-32, 25% R-125, and 52% R-134a by weight. The mixture exhibits a small temperature glide during phase change, typically around 3 to 4 K, reflecting its non-azeotropic nature, meaning the liquid and vapor phases do not have the same composition at a given temperature.

R-407C has zero ozone depletion potential and is classified as a non-flammable refrigerant (ASHRAE safety classification A1). Its global warming potential is high relative to CO2, typically quoted in the approximate range of 1,600 to 1,700 over a 100-year horizon. Because of the blend’s composition, equipment charged with R-407C often requires compatible lubricants, such as polyol esters (POE), and systems previously using mineral oil may need flushing and oil changes during retrofit.

Applications and performance considerations: R-407C is designed to provide cooling performance similar to R-22 in many standard air conditioning and heat pump units, though it may operate at higher suction pressures and require adjustments in system design and charging. It is widely used in both residential and commercial HVAC equipment and is supported by many manufacturers.

Environmental and regulatory context: While it does not deplete the ozone layer, R-407C is subject to regulatory actions aimed at reducing high-GWP refrigerants. In some markets, substitutions or transitions to lower-GWP blends are encouraged, influencing equipment designs and service practices.