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【答案】应助回帖
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对吻鱼(金币+5): 呵呵，回答的不错~~外行的飘过~~ 2011-05-06 20:01:18
mlnjut(金币+5, TEPI+1): 不是很懂，但谷歌了一下，、、、、复合授予 2011-05-06 20:11:00
氟利昂-22（代号：Ｒ２２） Ｒ22也是烷烃的卤代物，学名二氟一氯甲烷，分子式为CHClF2，标准蒸发温度约为－41℃，凝固温度约为－160℃，冷凝压力同氨相似，单位容积标准制冷量约为454kcal/ｍ3。 Ｒ22的许多性质与Ｒ12相似，但化学稳定性不如Ｒ12，毒性也比Ｒ12稍大。但是，Ｒ22的单位容积制冷量却比Ｒ12大的多，接近于氨。当要求－40～－70℃的低温时，利用Ｒ22比Ｒ12适宜，故目前Ｒ22被广泛应用于－40～－60℃的双级压缩或空调制冷系统中。
Difluoromethane, also called HFC-32 or R-32, is an organic compound of the dihalogenoalkane variety. It is based on methane, except that two of the four hydrogen atoms have been replaced by fluorine atoms. Hence the formula is CH2F2 instead of CH4 for normal methane.
Property Value
Critical pressure (pc) 5.83 MPa
Critical temperature (Tc) 78.45 °C (351 K)
Compressibility factor (Z) 0.9863
Heat capacity at constant pressure (Cp) at 21 °C (70 °F) 0.043 kJ·mol−1·K−1
Heat capacity at constant volume (CV) at 21 °C (70 °F) 0.034 kJ·mol−1·K−1
Heat capacity ratio (κ) 1.253
Difluoromethane is a refrigerant that has zero ozone depletion potential. Difluoromethane in an zeotropic (50%/50%) w/w mixture with pentafluoroethane (R-125) is known as R-410A, a common replacement for various chlorofluorocarbons (aka Freon) in new refrigerant systems, especially for air-conditioning. The zeotropic mix of Difluoromethane with pentafluoroethane (R-125) and tetrafluoroethane (R-134a) is known as R-407A through R-407E depending on the composition. Likewise the azeotropic (48.2%/51.8% w/w) mixture with chlorotrifluoromethane (R13). As a refrigerant difluoromethane is classified as A2L - slightly flammable [2009 ASHRAE Handbook]. Although it has zero ozone depletion potential, it has global warming potential 675 times that of carbon dioxide, based on a 100-year time frame [May 2010 TEAP XXI/9 Task Force Report].
R125是制冷剂的一种，是一种混合物（HFC）类，对大气臭氧层没有破坏，其与R32混合成的R410a是一种新型的制冷剂，目前正用于各种空调。
R410a
Property Value
Formula 50% CH2F2/50% CHF2CF3
Molecular Weight (Da) 72.6
Melting point (°C) -155
Boiling point (°C) -48.5
Liquid density (30°C), kg/m3 1040
Vapour density (30°C), air=1.0 3.0
Vapor pressure at 21.1°C (MPa) 1.383
Critical temperature (°C) 72.8
Critical pressure, MPa 4.86
Gas heat capacity @ 1 atm, 30°C (kJ/(kg·°C)) 0.88
Liquid heat capacity @ 1 atm, 30°C, (kJ/(kg·°C)) 1.8 |
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