Are all Quasi-static Processes Reversible?

TL;DR

The paper argues that quasi-static processes, despite approaching zero entropy production, are not truly reversible because of an extraneous work term, challenging common assumptions in thermodynamics.

Contribution

It provides a detailed analysis showing that all quasi-static processes are inherently irreversible due to extraneous work, even with infinite intermediate steps.

Findings

Quasi-static processes are not reversible despite zero entropy production.

An extraneous work term prevents true reversibility in non-isothermal heat transfer.

Infinite intermediate reservoirs do not guarantee reversibility.

Abstract

A process, carried out in a stepwise manner, becomes quasi-static when the number of intermediate steps tends to infinity. Usually, the net entropy production approaches zero under this limiting condition. Hence, such cases are termed reversible. A favorite example is the introduction of an infinite number of intermediate-temperature reservoirs in between the source and the sink for a non-isothermal heat transfer process. We analyze the situation and conclude that such quasi-static processes are not reversible. Indeed, no non-isothermal heat transfer process can ever be made reversible due to an extraneous work term.