An innovative heat harvesting technology (HEATec) for above-Seebeck performance

Abstract

An innovative approach to heat energy harvesting (HEATec) is proposed in this paper. It consists of a two-step conversion of heat into electricity. The first step is a thermo-mechanical conversion by a bimetal and the second is an electromechanical conversion by a piezoelectric. The first developed prototypes show natural thermal resistance matching between their body and the interface with ambient air, and therefore do not need a heat sink in order to work. The available mechanical power (2.7 mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> measured in practice for a single bimetal, and extendable to theoretical 27 mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for 100 bimetals occupying the same surface) that can be converted into electricity may lead to a superior performance compared to the best commercial Seebeck devices. Analytical scaling laws for our technology have been established and show power density gain equal to the scaling factor, making it LSI integration favorable.