Exploitation of the thermotunnel effect for energy scavenging

Abstract

Over the past few years, MEMS and smart material technologies improvements have allowed autonomous sensor devices to become more and more widespread. As batteries are not always appropriate to power these systems, energy scavenging solutions from ambient power are currently being developed. In particular, many researches have been carried out to improve thermal to electrical energy conversion in ambient temperature gradients. Until now, thermoelectric materials are still the most employed for this application. However, the recent developments in nanoscale device structures open different perspectives. In these nanoscale systems, the heat transport is achieved between two electrodes thanks to electron tunneling. The thermotunnel effect is currently widely studied in the cooling configuration where it has already been shown that it is more efficient than the Peltier effect. We have decided to evaluate this effect in the reciprocal way of work with the objective of being able to power a small sensor node. Considering a device with a simplicial geometrical structure, a modeling has been developed in order to evaluate the feasibility of conversion of a thermal flow into an electrical power based on thermotunneling effect. Comparisons with thermoelectric performances at ambient temperature have been performed.