In this paper

the characteristics of ammonia refrigerant are described. The application status and existing problems of ammonia refrigeration systems both in China and abroad are analyzed. The development trends of ammonia refrigeration technology including system optimization

improvement of control technology

safety guarantee

and miniaturization of ammonia systems are discussed. Moreover

some main problems to be solved according to safety requirements of Design Codes and Manuals of ammonia refrigeration systems are indicated. In addition

the ideas of simplifying ammonia systems are presented. It is suggested that the development of smallscale ammonia refrigerant compressors should be speeded up

and the theoretical and experimental studies both on ammonia refrigeration equipment and on practical applications should be emphasized in China.