Optimized high performance thermoelectric generator with combined segmented and asymmetrical legs under pulsed heat input power

In this study, a segmented asymmetrical thermoelectric generator (SASTEG) is numerically investigated to optimize its electrical performance and mechanical reliability under transient and steady state conditions. The thermal and electrical performance of the SASTEG and TEG under transient and steady state heating conditions are studied and compared. A three-dimensional numerical model is developed and solved using finite element method in COMSOL 5.3 Multiphysics software. Temperature dependent thermoelectric material properties are considered, and the elastoplastic behaviour of copper and solder is accounted for in the thermal stress analysis. The initial SASTEG geometry used in this study is subsequently optimized to reduce the maximum von Mises stress developed in its legs while maintaining its enhanced power output. Results obtained show that the optimized SASTEG provided a power output enhancement of 117.11% compared to that of the conventional TEG under rectangular pulsed heat condition. Also, the asymmetrical leg geometry used in the SASTEG n-type leg provided a reduced thermal stress of 39.21% in the lower segment (cold side) compared to the symmetrical leg geometry used in the p-type leg lower segment. This study will provide vital guidance in the design of high-performance TEG with improved mechanical reliability.