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Automobile manufacturers began phasing in R-134a around 1993 [citation needed]. When older units leak or require repair involving removal of the refrigerant, retrofitment to a refrigerant other than R-12 (most commonly R-134a) is required in some jurisdictions. The United States does not require such conversion.
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.
Chlorodifluoromethane (R-22 or HCFC-22), a type of Freon. [9] [10] 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.
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.
between 4 and 5 for R-12 refrigerant; around 7.56 for water (At 18 °C) 13.4 and 7.2 for seawater (At 0 °C and 20 °C respectively) 50 for n-butanol [1] between 100 and 40,000 for engine oil; 1000 for glycerol [1] 10,000 for polymer melts [1] around 1 × 10 25 for Earth's mantle.
The second automotive air conditioning refrigerant invented was R-134a. R-134a is a hydrofluorocarbon refrigerant that contains fluorine and hydrogen. The successor to R-12, R-134a was a new refrigerant that no longer contained chlorine that could deplete the ozone layer. R-134a is a greenhouse gas, it has a lower global warming potential than ...
Death rates fell among highly affected HIV subpopulations. Medical breakthroughs have reduced death rates for Americans with HIV, including groups that are disproportionately affected by the virus.
CARE 30 is a refrigerant consisting of a blend of isobutane (R-600a) and propane (R-290) developed to replace dichlorodifluoromethane (R-12) and 1,1,1,2-tetrafluoroethane (R-134a). [1] It is primarily for use in small commercial refrigeration and air-conditioning systems that have traditionally used R-12.