REVIEW OF AC, HEAT PUMP AND REFRIGERATION SYSTEMS USING NATURAL REFRIGERANTS

摘要

This paper gives a review of historical and recent developments regarding air conditioners, heat pumps and refrigeration systems using natural refrigerants. The progression and properties of the natural refrigerants, ammonia, carbon dioxide and hydrocarbons, are reviewed. The application of natural refrigerants in different systems are reviewed. The efficiency of carbon dioxide vapor compression system can be improved using an ejector as the expansion device and internal heat exchangers. The safety of hydrocarbon systems can be improved by introduing fire retardants into the mixture refrigerants. The future refrigerants for air conditioning, heat pump and refrigeration systems are discussed. This review will be useful for the further research on natural refrigerants and their systems.