Piezoelectric energy harvester operating in flowing water

An energy harvesting system is presented that converts energy out of flowing media, like water or wind. Without the need for any rotating part the harvester converts the energy out of the bending of a piezoelectric cantilever. A bluff body, which the cantilever is attached to, causes vortices and therefore pressure differences above and beneath the cantilever. Thus the cantilever oscillates and generates an alternating voltage. A first macroscopic model proofed this working concept for air and water. Measurements showed good coupling between flow velocity and power generation. Furthermore a self synchronization of different cantilevers could be observed in water. A second model of the harvester was build with improved distribution of piezoelectric layers. To store and distribute the generated energy of the harvester, it was combined with a low power circuit that was developed, too. Therefore, a complete autonomous system that is able to supply a load and the necessary electric circuit with power is presented.