Thermodynamic Performance Analysis of Eco friendly Refrigerant Mixtures to Replace R22 Used in Air Conditioning Applications

In the present study theoretical thermodynamic performance of a 0.8 TR window air conditioner with ten binary refrigerant mixtures consists of propylene (R1270) and propane (R290) was investigated based on actual vapour compression refrigeration cycle. All the investigated refrigerant mixtures consist of zero ozone depletion potential. Global warming potential of R22 is 1760 whereas GWP of all the studied refrigerant mixtures were below three and also these mixtures are closer to azeotropic containing the temperature glide below 0.4 o C. Thermodynamic performance of all the refrigerant mixtures are computed at the evaporating and condensing temperatures of 7.2 o C and 54.4 o C (ARI conditions) respectively. The results revealed that the coefficient of performance for the mixture R1270/R290 (75/25 by mass %) was closer to R22. The percentage variation in cop for the mixture R1270/R290 (75/25 by mass %) was least by 0.97% among the ten investigated refrigerant mixtures when compared to R22. Refrigeration capacity of all the considered refrigerant mixtures was similar to that of capacity of refrigerant R22. The compressor discharge temperature for all the studied refrigerants were reduced in the range of 5.6-8.4 o C when compared to the reference refrigerant R22. The power required per ton of refrigeration for the refrigerant mixture R1270/R290 (75/25 by mass %) was least among the ten investigated refrigerant mixtures. Since refrigerant mixtures consist of hydrocarbons, therefore they had better miscibility with the mineral lubricant oil. Overall the thermodynamic performance of a refrigerant mixture R1270/R290 (75/25 by mass %) was nearest to R22 and hence it is a suitable environmentally alternative refrigerant to substitute R22 used in residential air conditioning applications.