Effect of heat dissipation on the performance of thermoelectric generator

Abstract

Thermoelectric generators (TEGs) can directly convert heat into electricity with the advantages of ultra-silence, fast response, and high-power density, but the practical application is limited by their low conversion efficiency. We find that the heat dissipation caused by heat convection and heat exchange is an important factor in inhibiting the conversion efficiency. To reveal the effect of heat dissipation on the performance of TEGs, the theoretical model for the thermal-electric coupling of TEGs is built, while experimental research is taken to determine key parameters of heat transfer in theory and to verify theoretical models. Results show that both heat convection and heat exchange in TEGs severely inhibit the conversion efficiency by improving the heat consumption, but have no effect on the output power for a determined temperature gradient. According to theoretical results, the size of TEG is designed to improve the conversion efficiency by suppressing the impact of heat dissipation, while a vacuum encapsulation is proven to have the ability to eliminate both heat convection and heat exchange. As a result, the conversion efficiency of a Bi2Te3-based TEG is improved by 52% from the commercial TEGs. These findings provide a theoretical basis and guidance for obtaining high-performance TEGs.