Carnot efficiency is reachable in an irreversible process

TL;DR

This paper demonstrates that the Carnot efficiency can be achieved in an irreversible process using the Feynman-Smoluchowski ratchet, challenging the traditional belief that reversibility is necessary for maximum efficiency.

Contribution

It provides a proof that Carnot efficiency is attainable in irreversible processes and shows how irreversibility can be exploited to enhance efficiency.

Findings

Carnot efficiency is reachable in an irreversible process

Efficiency can be increased by increasing irreversibility

Feynman-Smoluchowski ratchet can operate at Carnot efficiency

Abstract

In thermodynamics, there exists a conventional belief that "the Carnot efficiency is reachable only when a process is reversible." However, there is no theorem proving that the Carnot efficiency is unattainable in an irreversible process. Here, we show that the Carnot efficiency is reachable in an irreversible process through investigation of the Feynman-Smoluchowski ratchet (FSR). We also show that it is possible to enhance the efficiency by increasing the irreversibility. Our result opens a new possibility of designing an efficient heat engine in a highly irreversible process and also answers the long-standing question of whether the FSR can operate with the Carnot efficiency.