Efficiency at optimal performance: A unified perspective based on coupled autonomous thermal machines
Abstract
We show that coupled autonomous thermal machines, in the presence of three heat reservoirs and following a global linearirreversible description, can have efficiency at maximum power (EMP) which is analogous in form to the EMP of models with two (hot and cold) reservoirs. In particular, the temperature dependence of EMP in the coupled model is via only the ratio of hot and cold temperatures if the intermediate reservoir temperature is expressed as an algebraic mean of these temperatures. Many popular expressions of EMP in the literature can be recovered by making a choice of some standard mean. Further, the universal properties of EMP near equilibrium can be explained in terms of the properties of symmetric means. For the case of broken timereversal symmetry, a universal secondorder coefficient of 6/49 is predicted in the series expansion of EMP, analogous to the 1/8 coefficient in the timereversal symmetric case.
 Publication:

Physical Review E
 Pub Date:
 April 2022
 DOI:
 10.1103/PhysRevE.105.044145
 arXiv:
 arXiv:2112.00660
 Bibcode:
 2022PhRvE.105d4145J
 Keywords:

 Condensed Matter  Statistical Mechanics;
 Quantum Physics
 EPrint:
 Revtex42,7 pages, 2 figures, 1 table