Dynamic thermoelectric generation enables 50% increase of efficiency at maximum power

Abstract

Thermoelectric generators are devices capable to convert heat into electric power with no moving part. However, and despite a tremendous research effort on materials, their conversion efficiency is still limited, especially in the low temperature range where most of the discarded heat is available. We show that the exact solution of the time-dependent Domenicali’s equation predicts that, when the temperature difference across the thermoelectric legs is modulated in time, efficiency at maximum power (${\eta }_{\text{MP}}$) improves by up to 50% compared to the stationary case — with a power output equivalent to that attainable by doubling the material figure of merit. Building on this evidence, we additionally show how, even for sources delivering heat at a constant rate, simple heat flux pre-processing leads to a comparable ${\eta }_{\text{MP}}$ improvement. Since the operational mode we propose is material-agnostic and does not require changes of the device layout, it could find prompt application.