Closed-loop approach to thermodynamics

TL;DR

This paper introduces a feedback loop framework for analyzing linear nonequilibrium thermodynamics in heat engines, linking efficiency, power, and frequency through feedback and gain parameters.

Contribution

It develops a novel, abstract approach using feedback theory to understand thermodynamic energy conversion processes more efficiently.

Findings

The system's behavior is characterized by feedback factor and open-loop gain.

Efficiency, power, and frequency are interconnected via the product of feedback and gain.

The approach applies broadly to any conversion engine with definable feedback.

Abstract

We present the closed loop approach to linear nonequilibrium thermodynamics considering a generic heat engine dissipatively connected to two temperature baths. The system is usually quite generally characterized by two parameters: the output power $P$ and the conversion efficiency $\eta$, to which we add a third one, the working frequency $\omega$. We establish that a detailed understanding of the effects of the dissipative coupling on the energy conversion process, necessitates the knowledge of only two quantities: the system's feedback factor $\beta$ and its open-loop gain $A_{0}$, the product of which, $A_{0}\beta$, characterizes the interplay between the efficiency, the output power and the operating rate of the system. By placing thermodynamics analysis on a higher level of abstraction, the feedback loop approach provides a versatile and economical, hence a very efficient, tool for the study of \emph{any} conversion engine operation for which a feedback factor may be defined.