Harvesting thermal energy via tube-based triboelectric nanogenerators within an oscillating heat pipe

Developing energy harvesting and conversion technology is of great significance to mitigate the energy crisis and realize the sustainable development of human society. In this work, we designed and fabricated a thermal energy harvesting and conversion device by integrating a tube-based triboelectric nanogenerator (TENG) into a copper oscillating heat pipe (OHP). The tube-based TENG was composed of two copper electrodes uniformly distributed along a polytetrafluoroethylene (PTFE) tube. The copper OHP with an inner diameter of 2 mm had 6 turns and deionized water (DI) was chosen as the working fluid. When thermal energy was added to the OHP, liquid plugs in the OHP were thermally excited and flowed into the PTFE tube, resulting in the generation of an alternating flow of electrons between the two electrodes. This TENG-OHP system successfully generated more than 7.0 V of open-circuit voltage and more than 0.32 μW of output power. The generated electrical energy can be used to power many small electronics, such as capacitors and light-emitting diodes (LEDs). Therefore, these findings will offer an alternative approach to harvest and convert thermal energy heat in many devices or systems that involve the heat generation and heat transfer process.