Analysis Of Thermoelectric Generator Incorporating N-Magnesium Silicide And P-Tetrahedrite Materials

Thermoelectric (TE) generators allow the direct conversion of heat into electricity without moving parts and with little maintenance needs if carefully designed. However, their high cost per unit power produced has prevented their widespread use in waste heat recovery applications. The use of earth-abundant, affordable, non-toxic and performant TE materials such as n-silicide and p-tetrahedrite for TE generators is assessed in the present analysis. A full multiphysics model was used to optimize the geometry of an n-p TE pair/module using these materials and assess its performance. The approach taken implemented the matched load condition automatically and a broad range of conditions was tested and discussed. Several pairs with the optimal geometry were preliminarily manufactured, assembled and characterized. The experimental results were compared against the predictions, allowing to validate the multiphysics model. Power densities up to 5 kW/m2 were predicted for temperatures between 290 K and 620 K, with efficiencies up to 5%. If modules with such performance could be manufactured with electric contact resistances comparable to those found in currently available commercial modules, then a door to the viable recovery of waste heat in industrial and automotive applications could be opened.