低温制冷机的性能评价

作为对制冷系数COP概念的补充,建议采用yong效率（Exergy Efficien-cy）的概念来综合评价多级低温制冷机的性能,同时也为其性能优化过程提供理论指导。本文还以yong效率为基础,综合评价了4.2K和80K温区低温制冷机的发展水平,具有一定参考价值。

PERFORMANCE EVALUATION METHOD FOR MULTISTAGE CRYOCOOLERS

The performance of a cryocooler is usually expressed in terms of the coefficient of performance, COP This is the ratio of the heat extracted to the work done According to the second law of thermodynamics,the coefficient of performance of Carnot cycle has the maximum theoretical COP attainable by a refrigerator operating between temperature limits given So the Carnot value is the reference index for all other refrigerators A refrigerator"efficiency"is sometimes quoted as the ratio of actual COP to the Carnot According to the requirements of applications,it is necessary for a modern multistage cryocooler to supply cooling power at different temperatures simultaneously Depending on definition of COP ,we find that it is very difficult to compare the performance among such multistage cryocoolers In this paper exergy efficiency is proposed as a new reference index to compare the performance and it can also be used to direct the design and optimization processes of cryocoolers