Waste-heat harvesting using a thermoelectric generator coupled with a hygroscopic hydrogel for use in the energy industry

With the ever-fast development of devices and their high requirements, such as the increased working speed of computers, high energy density of batteries, and high energy transfer efficiency of solar photovoltaic panels, excessive heat is generated, which may lead to performance degradation, system crashes, or even damage. Therefore, effective thermal management systems are needed to control the temperature of the device and avoid energy waste. This study proposes an integrated thermal management system, which contains a hygroscopic hydrogel and a thermoelectric generator (TEG). The hygroscopic hydrogel regenerates by adsorbing water molecules from the atmosphere after losing water, making it reusable and long-lasting without the need for replacement. When a TEG is combined with a 5-mm-thick hydrogel as the thermal management structure, it is able to reduce the surface temperature of the heat source by 32 °C and convert the waste heat to electricity with a 0.20 V output under a 3-W input power for the heat source. Based on this excellent performance, this novel integrated thermal management structure provides a new perspective for future thermal management strategies, particularly for the effective thermal management of heating devices such as solar panels, energy storage batteries, and large electrical equipment. © The Royal Society of Chemistry 2024.