Thermodynamic Performances of Coupled Autonomous Heat Devices: Insights from the Trade-off Optimization

Performance optimization of heat devices is of great significance for the efficient utilization of energy. In the context of irreversible thermodynamics, the thermodynamic behaviors of coupled autonomous(CAU) heat engines(refrigerators) under the trade-off criterion are studied. The analytical formulas of power(cooling power) and efficiency [coefficient of performance(COP)] are not only formulated, but also the thermodynamic bounds of efficiency(COP) are presented. In the physically allowed space, optimal characteristics of CAU heat engines(refrigerators) are detailedly elucidated, and the energetic advantages of trade-off optimization are highlighted. Besides, when the temperature of the intermediate reservoir is set to be specific mean values of the hot and cold temperatures, both efficiency and COP are definitely given. These results have certain theoretical and practical significance for designing and manipulating real-life heat engines(refrigerators).