Thermoelectric energy converters under a trade-off figure of merit with broken time-reversal symmetry

TL;DR

This paper analyzes the performance of three-terminal thermoelectric devices with broken time-reversal symmetry using a trade-off figure of merit, showing that different optimization criteria yield better results depending on the device's function.

Contribution

It introduces a unified trade-off figure of merit for thermoelectric devices with broken time-reversal symmetry and compares performance under different optimization criteria.

Findings

Maximum $ ext{Ω}$ criterion improves heat engine performance.

Maximum cooling load outperforms $ ext{Ω}$ criterion for refrigerators.

Results guide optimal operation criteria for thermoelectric devices.

Abstract

We study the performance of a three-terminal thermoelectric device such as heat engine and refrigerator with broken time-reversal symmetry by applying the unified trade-off figure of merit ($\dot{\Omega}$ criterion) which accounts for both useful energy and losses. For heat engine, we find that a thermoelectric device working under the maximum $\dot{\Omega}$ criterion gives a significantly better performance than a device working at maximum power output. Within the framework of linear irreversible thermodynamics such a direct comparison is not possible for refrigerators, however, our study indicates that, for refrigerator, the maximum cooling load gives a better performance than the maximum $\dot{\Omega}$ criterion for a larger asymmetry. Our results can be useful to choose a suitable optimization criterion for operating a real thermoelectric device with broken time-reversal symmetry.