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HC-12a, also called ES-12a, OZ-12a, DURACOOL 12a [1] and Hydrocarbon Blend B, is marketed as a "drop-in" replacement refrigerant for R-12 and other refrigerants. HC-12a is a mixture of hydrocarbons, specifically propane (R-290) and isobutane (R-600a), and is therefore considered nearly non-ozone-depleting.
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.
R-407C is a mixture of hydrofluorocarbons used as a refrigerant. It is a zeotropic blend of difluoromethane (R-32), pentafluoroethane (R-125), and 1,1,1,2-tetrafluoroethane (R-134a). Difluoromethane serves to provide the heat capacity, pentafluoroethane decreases flammability, tetrafluoroethane reduces pressure. [ 1 ]
Dichlorodifluoromethane (R-12 or CFC-12), the most commonly used Freon brand refrigerant prior to its ban in many countries in 1996 and total ban in 2010. 1,1,1,2-Tetrafluoroethane (R-134a or HFC-134a), one of the main replacements for the formerly widespread R-12. Opteon halogenated olefins now replacing Freons in many applications.
Common absorption refrigerators use a refrigerant with a very low boiling point (less than −18 °C (0 °F)) just like compressor refrigerators.Compression refrigerators typically use an HCFC or HFC, while absorption refrigerators typically use ammonia or water and need at least a second fluid able to absorb the coolant, the absorbent, respectively water (for ammonia) or brine (for water).
Molybdenum-99 is produced commercially by intense neutron-bombardment of a highly purified uranium-235 target, followed rapidly by extraction. [8] It is used as a parent radioisotope in technetium-99m generators to produce the even shorter-lived daughter isotope technetium-99m, which is used in approximately 40 million medical procedures annually.
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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 ]