Thermal Effect of Ceramic Substrate on Heat Distribution in Thermoelectric Generators

In thermoelectric generators (TEG), poor system design and load matching, which make the system less efficient, have been limiting factors in achieving high conversion efficiency. In this work, to consider the effect of the inlet plenum arrangement and the laminar coolant flow temperature variation in the heat sink, a parallel microchannel heat sink is applied to a real TEG. The focus of this study is a discussion of the temperature difference variation between the cold/hot sides of the TEG legs versus the variation of the thermal conductivity of the ceramic substrate and the thickness of the substrate on the hot side. While the imposed heat flux on the TEG is homogeneously constant, different pressure drops are applied along the microchannel heat sink. The three-dimensional governing equations for the fluid flow and heat transfer are solved using the finite-volume method. The results show that the temperature difference is affected remarkably by the pressure drops in the heat sink, the thermal conductivity of the ceramic substrate, and the thickness of the substrate on the hot side.