Analysis of bimetal-based thermal energy harvester using Piezoelectric materials

Abstract

A bimetallic cantilever with a piezoelectric patch at the top surface was used for thermal energy harvesting. The reciprocating nature of the heat source was modeled by providing sinusoidal temperature variation to the stationary heat source. The temperature of the heat source oscillated between 45 °C to 145 °C. Heat transfer from the heat source to the bimetallic beam was modeled using heat transfer in solids and fluids and laminar flow. The finite element analysis of the parameter variation of the bimetallic piezoelectric energy harvester was done in COMSOL. The parameters affecting the geometrical and substrate material properties were analyzed. In this regard, the effect of a difference in the coefficient of thermal expansion (CTE) of the bimetallic beam, length and position of the piezoelectric patch was observed to increase power output. Similarly, parameters such as the difference in density, the bimetallic beam's thermal conductivity, and the piezoelectric patch's thickness decreased the power output. Power law was used to fit the variation of power with different parameters. Finally, two empirical relations were built to analyze the power variation with geometrical and substrate parameters.