A Novel Piezoelectric System for Thermal Energy Harvesting from Temperature Fluctuations

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This study presents the analytical modeling of a novel, simple, practical, and environmentally-friendly piezoelectric thermal energy harvester which consists of two main components: a substance exposed to a fluctuating heat source (a solid elastic material or a pressurized gas) and a piezoelectric layer to generate electrical power. Thermal variations resulting from the fluctuating heat source within the substance are converted into pressure fluctuations in the piezoelectric layer, which generates useful electric power. Unlike the widely-used thermal energy harvesters that utilize thermoelectric materials, thermal power cycles, and pyroelectric generators, the proposed system utilizes piezoelectric materials that are common for their electromechanical conversion characteristics. Thermoelastic analysis is carried out to illustrate and evaluate the performance of the model. It is found that the generated power is affected by the heat source intensity and frequency, thermal losses, properties of the medium exposed to the thermal fluctuations, and the piezoelectric properties. It is also found that the model that uses a solid elastic material is more efficient than the one that uses a pressurized gas.​