Hydrocarbons as refrigerants-a review

Abstract

Refrigerants used in air conditioning and refrigeration (AC&R) industries have come full circle since the beginning of the industrial revolution. With concern on issues relating to the environment such as the global warming and climate change issues, we should find a better alternative than to continue using these refrigerants that cause global warming and ozone depletion. AC&R industry players have blended in by introducing some new equipment and components that are specifically designed for hydrocarbon (HC) use. Most new refrigerators sold in Malaysia are already equipped with isobutane [a hydrocarbon designated as R-600a by the American Society of Heating, Refrigerating and Air- Conditioning Engineers (ASHRAE) standards] as refrigerants. Malaysia has ratified the Montreal Protocol and targetted a 10% reduction in hydrochlorofluorocarbon (HCFC) consumption, beginning 2016 with the banning of 2.5 horsepower (hp) and below in air-conditioning (AC) equipment to be used. Instead, hydrofluorocarbon (HFC) R-410a was introduced as a replacement for HCFC- 22, whereas in other countries this HFC has been phased down. This article was initiated because of the difficulty in finding a replacement for HCFC. Also, the possibilities of using HC as an alternative to replace HCFC instead of using HFC as a transitional refrigerant in place of HCFC is reviewed in this article. The performance of HC is very similar to HCFC and flammability issues could be easily overcome with the use of an effective design. Their use could be facilitated with the adaptation of specific standards and properly enacted legislation.