Thermodynamic performance bounds for radiative heat engines

TL;DR

This paper derives analytical bounds on the efficiency and power trade-offs for radiative heat engines, showing they can outperform linear engines and providing metrics for thermophotovoltaic device evaluation.

Contribution

It introduces exact performance bounds for radiative heat engines, including reciprocal and nonreciprocal types, advancing understanding of their efficiency-power trade-offs.

Findings

Radiative engines can surpass linear engine trade-offs.

Derived simple analytical expressions for performance bounds.

Metrics provided for thermophotovoltaic device comparison.

Abstract

Heat engines cannot generally operate at maximum power and efficiency, imposing a trade-off between the two. Here, we highlight the exact nature of this trade-off for engines that exchange heat radiatively with a hot source. We derive simple analytical expressions for the performance bounds of reciprocal and nonreciprocal radiative heat engines. We also highlight that radiative engines can achieve a better power-efficiency trade-off than linear ones. These bounds are especially relevant for thermophotovoltaics, offering useful metrics against which to compare device performance.