Inhomogeneous Thermal Conductivity Enhances Thermoelectric Cooling

TL;DR

This paper theoretically demonstrates that inhomogeneous thermal conductivity in thermoelectric materials can significantly improve cooling power and temperature difference, mainly through asymmetric Joule heat dissipation, despite only slight increases in traditional efficiency metrics.

Contribution

It introduces the concept that inhomogeneous thermal conductivity enhances thermoelectric cooling by asymmetric Joule heat dissipation, beyond traditional figure of merit improvements.

Findings

Maximum cooling power is significantly increased.

Maximum cooling temperature difference is significantly increased.

Thermal rectification occurs due to asymmetric Joule heat dissipation.

Abstract

We theoretically investigate the enhancement of thermoelectric cooling performance in thermoelectric devices made of materials with inhomogeneous thermal conductivity, beyond the usual practice of enhancing thermoelectric figure of merit ZT. The dissipation of Joule heat in such thermoelectric devices is asymmetric which can give rise to better thermoelectric cooling performance. Although the thermoelectric figure of merit and the coefficient-of-performance are only slightly enhanced, both the maximum cooling power and the maximum cooling temperature difference can be enhanced significantly. This finding can be used to increase the heat absorption at the cold end. The asymmetric dissipation of Joule heat also leads to thermal rectification.