Maximum work for Carnot-like heat engines with infinite heat source

TL;DR

This paper analyzes the maximum work output and efficiency bounds of Carnot-like heat engines with linear heat transfer laws, revealing the CA efficiency as an upper bound and finite extractable work.

Contribution

It derives the efficiency upper bound independent of process duration and conductance, and characterizes optimal temperature profiles in heat exchange processes.

Findings

Efficiency upper bound is the Carnot efficiency.

Work extracted remains finite despite heat exchange.

Endoreversible model is recovered under specific contact time conditions.

Abstract

An analysis of efficiency and its bounds at maximum work output for Carnot-like heat engines is conducted. The heat transfer processes are described by the linear law with time-dependent heat conductance. The upper bound of efficiency is found to be the CA efficiency,and is independent of the time duration completing each process and the time-dependent conductance. We prove that even the working medium exchanges heat sufficiently with the heat reservoirs, the work which could be extracted is finite and limited. The optimal temperature profiles in the heat exchanging processes are also analyzed. When the dimensionless contact times satisfy certain relations,the endoreversible model is recovered.