Coupled thermo-electric-mechanical modeling of hybrid thermoelectric-piezoelectric energy harvester

If piezoelectric (PE) layers are bonded on the heat sink of thermoelectric (TE) generators, waste thermal and wind energy can be simultaneously converted into electricity. This study investigates the coupled thermo-electric-mechanical behavior and the effect of material parameters and structure dimensions on the energy collection performance of this hybrid TE-PE system. The model is based on Hamilton's principle to obtai the governing equations of hybrid system. Numerical results show that output powers of TE part and PE part could be improved simultaneously when thermal conductivity of heat sink increases. If the thermal conductivity of TE material is reduced by 20%, the output power of PE part could be reduced by 7.39%, and the output power of TE part could be increased by 44.7%. With a specific length of heat sink, the output power of PE part can be increased by 41% and the output power of TE part can be reduced by 0.72% compared to that without changing the hybrid system size. Therefore, it is possible to adjust the material parameters and structure dimensions to achieve higher performance of hybrid TE-PE system. The results obtained here may offer valuable references for optimal design of hybrid TE-PE energy harvester.