Efficient ecological function analysis and multi-objective optimizations for an endoreversible simple air refrigerator cycle.

Combining finite time thermodynamics and exergetic analysis, analogous to the definition of ecological efficient power for heat engines, this paper proposes a unified performance indicator for various cycles, exergy-based efficient ecological function (<italic>E</italic> <italic>ɛ</italic> ) which is defined as product of exergy-based ecological function and coefficient of performance, and introduces it into performance optimization of endoreversible simple air refrigerator cycle coupled to constant-temperature heat reservoirs. Relations among <italic>E</italic> <italic>ɛ</italic> , pressure ratio (<italic>π</italic>) and heat conductance distribution ratio (<italic>u</italic>) are derived by using numerical method. The cycle performance indicators which include cooling load (<italic>R</italic>), coefficient of performance (<italic>ɛ</italic>), and exergetic loss rate (<italic>E</italic> out/<italic>T</italic> 0) under the different maximum objective criteria are compared. Taking <italic>π</italic> as optimal variable, and taking <italic>R</italic>, <italic>ɛ</italic>, cooling load density (<italic>r</italic>), <italic>E</italic> <italic>ɛ</italic> and their combinations as optimization objectives, multi-objective optimizations, totally 15 optimization combinations, are performed by using NASG-II algorithm. The results demonstrate that, the maximum <italic>E</italic> <italic>ɛ</italic> criteria can better reflect the compromise among <italic>R</italic>, <italic>ɛ</italic> and <italic>E</italic> out/<italic>T</italic> 0. The Pareto solution sets are majorly distributed in 2.5–20 when quadru-objective optimizations are performed. The option selected by LINMAP decision-making method is closer to ideal solution when bi-objective optimization of <italic>ɛ</italic> and <italic>r</italic> is carried out. [ABSTRACT FROM AUTHOR]