Numerical analysis of energy conversion efficiency and thermal reliability of novel, unileg segmented thermoelectric generation systems

Despite their great potential to recover waste heat, thermoelectric generators (TEGs) find limited usage since thermoelectric materials are only efficient within a limited temperature range. Using multiple materials in segmented TEGs can significantly enhance the overall energy conversion efficiency. However, thermal reliability is questionable in these systems especially at elevated temperatures and in annular configurations. This study explores the feasibility of utilizing unileg (single material) segmented TEG configuration as a remedy for the thermal stress problem. This study introduces the concept of unileg, segmented thermoelectric configurations (flat and annular) for the first time, and three-dimensional finite element simulations are conducted to investigate the thermoelectric performance and thermal reliability analysis in comparison with the conventional unicouple (dual material) systems. Results indicate that thermal stresses are significantly lowered in unileg systems compared to the unicouple configuration. In addition to the enhanced thermal reliability, power generation and thermoelectric conversion efficiency are higher in unileg systems since the material with higher performance is used solely eliminating the need of poorly performing, second thermoelectric leg material.