Thermoelectric waste heat recovery of an automotive internal combustion engine using (Na, K) co-doped polycrystalline tin selenide (SnSe)

Abstract

Recent developments in converting the thermal energy of exhaust gasses of auto-mobiles into electric power directly, require an extensive simulation and design of appropriate TEG system. This work aims to create a physical model of engine exhaust system using Simscape language to simulate waste heat recovery from the exhaust gasses using (Na, K) co-doped polycrystalline tin selenide, SnSe, TE material. This particular material exhibits a high Seebeck coefficient and extremely low lattice thermal conductivity in power generation because of phonons scattering by the rattlers (Na, K atoms) and nanostructuring. In the MATLAB/SIMULINK environment, a transient simulation is done for the recovery of waste heat from a 1.5 liters engine using these specific material-based TE modules. According to the results obtained, at the temperature gradient of 285 K across its sides, electrical power of 10.4 W with a conversion efficiency of almost 5% is produced from one module. The total system output power was 477 W at the exhaust gas inlet temperature of 900 K to the octagonal HEx on which the modules are mounted.