Hydrocarbons are natural fluids which create less environmental effect in nature and cause less emission also. This paper emphasizes the heat-transfer performances and global warming potential of the existing refrigerant, R-22, and compares it with some hydrocarbon mixtures for the domestic air conditioner. Propane with different proportions is taken for comparison. R-134a and R-407C are also used as refrigerants in the refrigerators and in commercial or large scale air conditioners, respectively. Two mixtures of R-290 with R-22 having proportions 25: 75 and 50: 50 by mass are used for comparison. Global warming potential of R-22 is high compared to that of R-290. But only R-290 is a high flammable refrigerant. Mixing of R-290 with R-22 reduces the global warming potential, and also reduces the flammability issue. This mixture finds better heat transfer enhancement compared to that of R-22. Thus, the heat transfer coefficient for the mixture increases up to 20-30 % compared to that of R-22. Indirectly it causes to reduce the requirement of refrigerant charges, and hence, the emission in the environment will also be reduced.
