内可逆空气制冷机性能的生态学优化

Ecological optimization of endoreversible air refrigerator

基于灯用分析的观点,运用有限时间热力学方法对内可逆空气制冷机进行生态学优化,导出了换热器热导最优分配时的最佳制冷功率、熵产率以及生态学(E)目标函数的解析式,进一步求得最大E目标值时的工质等熵温比(压比)界限及相应的制冷系数、制冷功率和熵产率;采用数值计算分析了热源温比、换热器总热导以及高温热源温度和环境温度之比对该制冷机生态学最优性能的影响。结果表明:生态学目标函数不仅反映了灯用输出率和熵产率之间的最佳折衷,而且也反映了制冷功率和制冷系数之间的最佳折衷。

Based on the exergetic analysis, an endoreversible air refrigerator was optimized ecologically by the finite-time thermodynamic method in this paper. Expressions for the optimal cooling load, the entropy generation rate and the ecological function of the refrigerator were derived by optimizing the heat exchanger inventory. The ecologically optimum isentropic temperature ratio, coefficient of performance （COP）, cooling load and entropy generation rate at maximum ecological function point were also obtained. Numerical examples were given to show the effects of the temperature ratio of the two reservoirs, the total heat exchanger inventory and the temperature ratio between heat sink and surroundings on the optimal performance of the refrigerator. The results obtained indicate that ecological function is not only a compromise between exergy output rate and entropy generation rate but also a compromise between cooling load and COP of an endoreversible air refrigerator.