Efficiency of inefficient endoreversible thermal machines

TL;DR

This paper investigates the performance limits of endoreversible thermal machines, including engines and refrigerators, using a quantum three-level maser model to derive analytical efficiency expressions under small thermodynamic forces.

Contribution

It introduces a detailed analysis of optimized endoreversible thermal machines in the small force regime, with explicit quantum model illustrations and analytical efficiency formulas.

Findings

Optimal performance depends on the flux-force relationship.

Explicit efficiency expressions are derived for the three-level maser.

Results highlight how thermodynamic forces influence machine efficiency.

Abstract

We present a study of the performance of endoreversible thermal machines optimized with respect to the thermodynamic force associated with the cold bath in the regime of small thermodynamic forces. These thermal machines can work either as an engine or as a refrigerator. We analyze how the optimal performances are determined by the dependence of the thermodynamic flux on the forces. The results are motivated and illustrated with a quantum model, the three level maser, and explicit analytical expressions of the engine efficiency as a function of the system parameters are given.