A Review of the Potential Replacements of HCFC/HFCs Using Environment-Friendly Refrigerants

The adequate and efficient performance of HVAC systems are signs of luxury and human comfort, and the improvement of their performance has been the target of continuous researches. Choosing the suitable refrigerant is the main parameter in matching the system components, selecting the type of heat exchangers, the compressor, the expansion device and the suitable lubricant. The theoretically ideal refrigerant is the one having zero ozone depletion potential (ODP), low global warming potential (GWP), nontoxic, nonflammable, has appropriate thermodynamic and heat transfer properties and is compatible with any type of lubricating oil. Chlorinated, fluorinated refrigerants, zeotropic and azeotropic mixtures satisfy many requirements, but have high ODP and GWP and are not compatible with all types of oil. Hydrocarbons (HCs) satisfy all the requirements except being highly flammable. This work reviews previous research aiming to find substitutes for the environmentally harmful refrigerants by other environmentally friendly ones and compare their performance in various HVAC appliances.