Fundamental limitations of thermoradiative energy conversion

TL;DR

This paper establishes fundamental thermodynamic bounds for thermoradiative energy conversion, showing these engines are inherently less efficient than radiative engines and providing a unified framework for their analysis.

Contribution

It derives general performance bounds for thermoradiative engines and unifies radiative and thermoradiative systems within a comprehensive thermodynamic framework.

Findings

Thermoradiative engines are bounded by radiative engine performance.

Unified thermodynamic framework for radiative and thermoradiative systems.

Raises questions about the practical relevance of thermoradiative cells.

Abstract

Understanding the fundamental limits of various energy conversion approaches is essential for assessing their efficiency and power output. In this work, we derive general performance bounds for thermoradiative heat engines that exchange heat radiatively with a cold sink, establishing power-versus-efficiency thermodynamic bounds for several configurations. We find that the performance of these engines is always bounded by that of radiative engines, which harness the thermal radiation emitted by a hot source, making thermoradiative engines inherently less favorable for energy conversion. By unifying the results of radiative and thermoradiative engines within a common thermodynamic framework, which also encompasses dual-engine configurations that combine both features, this work provides a comprehensive understanding of the thermodynamic limits of radiative energy conversion. Our framework offers general metrics for evaluating specific devices and raises critical questions regarding the relevance of thermoradiative cells for energy production.