Triple-mode hybridized generator for efficient water flow energy harvesting and water quality monitoring applications

Water quality monitoring is essential for river ecological environment. Harvesting water flow energy for river environmental monitoring is a promising solution for self-powered sensing technology. In this work, based on the triboelectric-electromagnetic (TENG-EMG) working principle, a comprehensive strategy appropriately hybridizes the solid-solid TENG (SS-TENG), solid-liquid TENG (SL-TENG) and EMG based on water wheel structure for harvesting water flow energy. The triple-mode hybridized generator (TMHG) in a limited space is combined effectively through ingenious structural design, which greatly improves the space utilization. An introduction of the combination of TMHG and buoy structure provides stable operating conditions for power supply. The basic TMHG in terms of structural parameters, response characteristics, power supply capacity and sensing characteristics is systematically discussed. Specially, after optimizing the structural parameters, the SS-TENG, SL-TENG and EMG deliver an instantaneous power of 1.44, 0.15 and 15.9 mW, and 480, 120 and 122 LEDs array can be simultaneously illuminated at the rotate speed of 90 rpm, respectively. The output of SL-TENG has strong correlation with flowing velocity and water PH, further demonstrating a potential application of TMHG on selfdriven sensing of river state. A triple-channel hybridized power management (TcHPM) strategy consisting of energy collection module, storage module and mechanical switch is developed to co-manage the electrical outputs of three generating modules in TMHG. Furthermore, a wireless self-powered monitoring system using TMHG as power supply is further developed and demonstrated for water quality monitoring in terms of water temperature and total dissolved solids. This paper not only provides a potential strategy towards effective water flow energy harvesting, but also demonstrates the potential applications of the TMHG in water quality monitoring.