Thermoelectric devices with rotated and coaxial leg configurations: Numerical analysis of performance

More efficient and durable thermoelectric devices are in high demand because of their ability to convert wasted energy into useful electrical energy. Structural integrity must be considered while developing thermoelectric devices because of its impact on power-generation and operation life-time. In this study, the effects of various leg configurations on thermo-mechanical integrity and power-generation performance of thermoelectric devices are investigated. Cylindrical four-leg devices with original-, rotated-, and coaxial-leg configurations are modeled for this purpose. Using these models, finite-element analyses are carried out under thermally steady-state and mechanically unconstrained conditions. The temperature level, the temperature distribution, the developed thermal stresses in the legs, the power output magnitudes, and the conversion efficiencies of the devices are examined individually for a defined temperature gradient. The results indicate that by using a coaxial-leg configuration, maximum thermal stresses in the legs can be reduced 10% while conversion efficiencies can be increased 7%. Models with coaxial-leg configurations also presented slightly different temperature distributions than the other configurations. The effect of rotated-leg configurations on thermal stresses and conversion efficiencies were less than 1.2% and 0.3%, respectively. This study aims to have an impact on considerations of leg configurations for the future of thermoelectric device development.