Mixtures of fluorinated ether and sulfur derivatives as chlorodifluoromethane (R-22) alternatives.

摘要

The refrigerant R-22 is used worldwide in the refrigeration and air-conditioning industry because of its desirable chemical and physical properties for refrigerant applications. However, it is scheduled to be phased out by the year 2015 by the Clean Air Act Amendment due to its ozone depletion potential. Since hydrofluorocarbons (HFCs) do not deplete ozone, they are considered primary CFC or HCFC replacements. Although there are currently two HFC mixtures, R-410A and R-407-C, being sold commercially as R-22 replacements, both of these alternatives have shortcomings. The refrigerant R-410A requires high operating pressures and R-407C fractionates during the evaporation cycle. The task of finding a better replacement for R-22 with the same performance or better is difficult because no HFC compounds can match the wide spread between the boiling point (-40.1°C) and critical temperature (96°C) for R-22. Consequently the search for finding an alternative to R-22 is oriented to finding the best alternative based on how nearly its coefficient of performance (COP) value approaches that of R-22. The coefficient of performance is equal to the heat removed from the surroundings during the evaporation portion of the refrigeration cycle relative to the work done during a complete cycle.; In conclusion, we have identified 6 alternatives (CF3OCF 2H, CH3CH2F, CF3SCF3/CH3CF2F, CF 3OCF2H/CF2H2/CH3CH 2F, CF3OCF2H/CF2 H2/CH3CF2H and CF 3OCF2H/CF2H2/CF3CH 2F) which have COP that exceed those of R-410A and R-407C, i.e. the COP exceeds values that are 75% of those of R-22. The most notable mixture is CF3SCF3/CH3CF2H with a relative COP value of 89% that of R-22. This azeotropic mixture COP value is about 13.4% and 17.6% higher those of current commercial alternatives, R-410A and R-407C, respectively.