Equivalent parameters for series thermoelectrics

TL;DR

This paper analyzes the physical processes at the interface of two thermoelectric generators connected in series, deriving equivalent parameters and highlighting the thermal-electrical symmetry with parallel configurations.

Contribution

It introduces a new derivation of the equivalent electrical series resistance and figure of merit for series thermoelectric generators, emphasizing the role of thermal continuity.

Findings

Derived the equivalent electrical series resistance considering thermal continuity.

Established the expression for the equivalent series figure of merit.

Highlighted the symmetry between series and parallel thermoelectric configurations.

Abstract

We study the physical processes at work at the interface of two thermoelectric generators (TEGs) thermally and electrically connected in series. We show and explain how these processes impact on the system's performance: the derivation of the equivalent electrical series resistance yields a term whose physical meaning is thoroughly discussed. We demonstrate that this term must exist as a consequence of thermal continuity at the interface, since it is related to the variation of the junction temperature between the two TEGs associated in series as the electrical current varies. We then derive an expression for the equivalent series figure of merit. Finally we highlight the strong thermal/electrical symmetry between the parallel and series configurations and we compare our derivation with recent published results for the parallel configuration.