Three-Dimensional Multiphysics Coupled Field Analysis of an Integrated Thermoelectric Device

Abstract

Thermoelectric elements made of semiconductor plates laminated onto a highly electrical and thermally conductive inter-connector with a flow channel configuration can be treated as an integrated thermoelectric device (iTED). An element constructed with bulk crystalline n- and p-type (Bismuth-Telluride) semiconducting materials and copper as a conducting material is considered. In this study, the thermoelectric performance of such an element using fluid-thermoelectric coupled field numerical methods has been investigated. The iTED is subjected to constant cold temperature at the bottom and top surfaces, while the inter-connector channel walls are exposed to hot fluid flow; the remaining surfaces are kept adiabatic. The performance of the iTED element is studied in terms of heat input Q _h , power output P ₀, conversion efficiency η, produced electric current and Ohmic and Seebeck voltages for different load resistances, inlet hot fluid temperatures T _in , semiconductor material heights d, and flow rates Re. For fixed T _in and Re, an optimum η is shown at a load resistance which is slightly lesser than total internal resistance value. An increase in T _in results in an enhancement in P ₀ and η; however, it has a minimal effect on the variation of optimum load resistance. At higher T _in values, the increment in load resistance showed a significant change in the heat input values. Both semiconductor material height and fluid flow rate had a prominent effect on iTED performance. The P ₀ and η are increased nearly three-fold and 1.6 times, respectively, at Re = 500 in comparison to Re = 100. Further, when d = 5 mm, approximately 1.7 times in P ₀ and 3.3 times in η are achieved compared to d = 1 mm values. It is recommended that for an accurate modeling, design and optimization of state-of-the-art TED with flow channels be carried out using multiphysics coupling field simulations.