Review of hydrocarbon refrigerants as drop-in alternatives to high-GWP refrigerants in VCR systems: The case of R290

Global warming issues are of enormous interest to researchers and decision-makers. Some refrigerants have a large share of harmful emissions to the environment, so it is necessary to shed light on eco-friendly refrigerants and demonstrate the feasibility of using them as alternatives to environmentally harmful refrigerants. From this standpoint, this review examines studies on hydrocarbon refrigerants with emphasis on R290 as alternatives to high global warming potential refrigerants in various vapor compression refrigeration systems, especially air conditioners and refrigerators with small cooling capacities. Also, thermophysical and environmental properties, advantages and disadvantages of hydrocarbon refrigerants, especially R290, and compatibility with lubricants were explained. This review showed that hydrocarbon refrigerants have unique properties in terms of thermal performance, environmental friendliness, non-toxicity and compatibility with lubricants, but the problem of flammability poses some challenges and limitations. R290 refrigerant is a highly effective substitute, whether used alone or in combination, and is particularly suitable for household refrigerators and small air conditioners because of its small gas charge size, which is considered somewhat safe from explosion. Furthermore, R290 boasts a high coefficient of performance, provided that the system undergoes the required adjustments. Some studies have shown that in domestic refrigeration applications, R134a can be replaced with R290 but using a lower displacement compressor. In this regard, this review can be a valuable reference for researchers and developers.