Refrigerants

Refrigerants - Refrigerants Background 1850's 1870's:...

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1 Refrigerants Background 1850’s – 1870’s: ammonia, ammonia/water, CO 2 Early 1900’s: SO 2 , methyl chloride used for domestic refrigerators 1930’s: halocarbon refrigerants discovered by Midgley (R-12, R-22, R-114, R-22) Halocarbon advantages – stable compounds, favorable thermodynamic properties, safer than existing refrigerants Ammonia still used for large low-T industrial plants
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2 Ozone Depletion Molina & Rowland (1974) hypothesized that Cl in CFC’s contributed to depletion of ozone (O 3 ) in upper atmosphere. CFC’s, HCFC’s, HFC’s Ozone Depletion, cont. CFC’s Most stable – remain in atmosphere for many years, allowing them to diffuse to high altitudes CFC’s break down, and Cl combines with and consumes some ozone HCFC’s Hydrogenated Not as stable – most of it breaks down before reaching high altitudes Less damaging to ozone
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3 Ozone Depletion, cont. HFC’s Contains no Cl Causes no depletion of ozone Montreal Protocol (1987) Called for curtailment of production of CRC’s
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This note was uploaded on 04/15/2008 for the course ME 113 taught by Professor Usaxena during the Spring '07 term at San Jose State.

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Refrigerants - Refrigerants Background 1850's 1870's:...

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