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Difluoromethane is a molecule used as refrigerant that has prominent heat transfer and pressure drop performance, both in condensation and vaporization. [6] It has a 100-year global warming potential (GWP) of 675 times that of carbon dioxide, and an atmospheric lifetime of nearly 5 years. [ 7 ]
HCFC-123 is used in large tonnage centrifugal chiller applications, and is the most efficient refrigerant currently in use in the marketplace for HVAC applications. HCFC-123 is also used as a testing agent for bypass leakage of carbon adsorbers in gas filtration systems, and as the primary chemical in Halotron I fire-extinguishing agent. [2]
According to ASHRAE standard 34, the R-number of a chemical refrigerant is assigned systematically according to its molecular structure and has between two and four digits. If there are carbon -carbon multiple bonds , there are four digits in all: the number of these bonds is the first digit and the number of carbon atoms minus one (C-1) is next.
In the atmosphere of Earth, anthropogenic tetrachloro-1,2-difluoroethane has been found to occur. Between 2017 and 2020 levels, were about 0.52 parts per trillion (ppt). Levels rose from the 1970s till about 1995. [9]
Because of its reduced global warming potential (GWP), R-454B is intended to be an alternative to refrigerant R-410A in new equipment. [2] [3] [4] R-454B has a GWP of 466, which is 78 percent lower than R-410A's GWP of 2088. [2] R-454B is non-toxic and mildly flammable, with an ASHRAE safety classification of A2L. In the United States, it is ...
R-410A was invented and patented by Allied Signal (later Honeywell) in 1991. [5] Other producers around the world have been licensed to manufacture and sell R-410A. [6] R-410A was successfully commercialized in the air conditioning segment by a combined effort of Carrier Corporation, Emerson Climate Technologies, Inc., Copeland Scroll Compressors (a division of Emerson Electric Company), and ...
[8] [9] [10] As of February 2020, 16 U.S. states ban or are phasing down HFCs. [ 11 ] COVID-19 relief legislation, which included a measure that would require chemical manufacturers to phase down the production and use of HFCs, was passed by the United States House of Representatives and United States Senate on December 21, 2020. [ 12 ]
A representative pressure–volume diagram for a refrigeration cycle. Vapour-compression refrigeration or vapor-compression refrigeration system (VCRS), [1] in which the refrigerant undergoes phase changes, is one of the many refrigeration cycles and is the most widely used method for air conditioning of buildings and automobiles.