Hydrocarbon refrigerants as sustainable alternatives to high-GWP refrigerants: a systematic review of R600 and R600a

Global warming has heightened the need for sustainable refrigerants with low global warming potential (GWP). This review evaluates hydrocarbon refrigerants—butane (R600) and isobutane (R600a)—as eco-friendly alternatives in vapor compression refrigeration systems, including air conditioners and domestic refrigerators. Their thermal, physical, and environmental properties are analyzed, along with practical challenges and advantages. Hydrocarbon refrigerants offer high energy efficiency, negligible ozone depletion potential (ODP), and very low (GWP≈3). They are also non-toxic and compatible with conventional lubricants. However, their high flammability requires careful system design and safety measures. Research confirms that R600 and R600a are viable replacements for high-GWP refrigerants like R134a, particularly in domestic refrigeration, where small refrigerant charges reduce flammability risks. R600 exhibits a superior coefficient of performance (COP), though system modifications are necessary for optimal efficiency. Studies suggest that using lower-displacement compressors can enhance performance when transitioning from R134a to R600 and R600a alternatives. While hydrocarbons present a promising solution for reducing environmental impact, their flammability remains a key limitation. Future research should focus on improving safety standards and expanding their applicability to larger systems. This review provides a comprehensive assessment for researchers and engineers, supporting the adoption of hydrocarbon refrigerants as a sustainable alternative, provided that proper safety protocols are implemented.