Harvesting heat energy from hot/cold water with a pyroelectric generator

Abstract

Waste heat has been regarded as one of the most important renewable and green energy sources, and its widespread reclamation could help to reduce the negative impacts of global warming and the energy crisis. In this work, we designed a pyroelectric generator based on a polyvinylidene fluoride film for harvesting the heat energy from hot/cold water, which widely exists in industrial processes. To achieve practical application, the device simply contacts a hot flow and cold flow alternately. The output open-circuit voltage and short-circuit current reached a maximum of 192 V and 12 μA, respectively, under a temperature change of 80 °C. The output power density can reach 14 μW cm, which is a great improvement for thermoelectric devices. The prepared pyroelectric generator can drive 42 green light-emitting diodes or charge a commercial capacitor (100 μF) to 3.3 V in 90 s. This work provides a promising strategy for efficiently harvesting waste heat from water and presents significant progress in thermoelectric conversion technology.