Global structural optimization of annular thermoelectric generators based on a dual-finite-element multiphysical model

Abstract

The conventional methods to improve the performance of annular thermoelectric generators (ATEGs) heavily rely on optimizing the thermal design of individual annular thermoelectric couples (ATECs). However, since a practical ATEG consists of many ATECs, the optimal structure of the ATEG can differ from the ATEC-based design. On the other hand, optimization by simply considering all ATECs can lead to a heavy computation burden. This work first proposes a high-fidelity, fluid-thermal-electric multiphysical ATEG model, solved by a computationally-efficient dual-finite-element method to cope with the challenge. This model explores the effects of ATEC microstructure and heat exchanger structure on ATEG performance under various operating conditions. Comparative multi-objective optimization studies were performed at three levels, i.e., for a single ATEC, a single ring of ATEG, and the entire ATEG. The results reveal that the optimized structural parameters of ATECs have some new features when considering the entire ATEG as the optimization objective. The optimal height, angle, and thickness of ATECs are 12 mm, 2.35°, and 10 mm, respectively. The corresponding net power, efficiency, and power density of ATEG are 321.6 W, 6.58 %, and 634.15 W/m3, respectively. Compared to the traditional design method based on a single ATEC and a single ring, the net power of the ATEG designed with the proposed method can be enhanced by 168 % and 197 %, respectively, at the expense of only a 20 % reduction in the power density.