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From 1930 to 1935, they developed dichlorodifluoromethane (CCl 2 F 2 or R12), trichlorofluoromethane (CCl 3 F or R11), chlorodifluoromethane (CHClF 2 or R22), trichlorotrifluoroethane (CCl 2 FCClF 2 or R113), and dichlorotetrafluoroethane (CClF 2 CClF 2 or R114), through Kinetic Chemicals which was a joint venture between DuPont and General Motors.
Normal boiling points for pure substances, bubble and dew points for zeotropic blends, or normal boiling point and azeotropic temperature for the azeotropic blends, at 101,325 Pa (1 atmosphere) and in degrees Celsius; Critical temperature in degrees Celsius; Absolute critical pressure in kilopascals
Worldwide production of R-22 in 2008 was about 800 Gg per year, up from about 450 Gg per year in 1998, with most production in developing countries. [2] R-22 use is being phased out in developing countries, where it is largely used for air conditioning applications.
In 2000 in the UK, the Ozone Regulations [45] came into force which banned the use of ozone-depleting HCFC refrigerants such as R22 in new systems. The Regulation banned the use of R22 as a "top-up" fluid for maintenance from 2010 for virgin fluid and from 2015 for recycled fluid. [citation needed]
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.
The first CFCs were synthesized by Frédéric Swarts in the 1890s. In the late 1920s, a research team was formed by Charles Franklin Kettering in General Motors to find a replacement for the dangerous refrigerants then in use, such as ammonia. [3]
What is a normal blood pressure reading? Updated May 17, 2019 at 1:19 PM. ... "Your blood pressure is supposed to be under 140 over 90, optimally closer to 120 over 80."
Since 1982, STP has been defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly 1 bar (100 kPa, 10 5 Pa). NIST uses a temperature of 20 °C (293.15 K, 68 °F) and an absolute pressure of 1 atm (14.696 psi, 101.325 kPa). [3] This standard is also called normal temperature and pressure (abbreviated as NTP).