Performance enhancement of a piezoelectric rain energy harvester

Using piezoelectric beam to harvest vibration energy from the impact of raindrop is a feasible approach in renewable energy conversion. There are some prototypes developed in recent years to demonstrate this concept. Following our previous works on mathematical modelling and experimental investigation of water droplets on a piezoelectric beam, we propose a design modification to enhance the performance of a piezoelectric rain energy harvester. The design incorporates a mechanism to direct water droplets to a syringe and hence able to convert raindrops into single water droplets. The enhancement strategy is to convert random raindrops to single water droplet impacts on an optimal position on the piezoelectric beam. The performance of the harvester was investigated under different rain conditions in a controlled environment via a raindrop simulator. The results show that the performance of the enhanced harvester has been improved by at least 208%. Besides that, a theoretical model is developed and good agreement is achieved in a comparison of simulation and experimental results. Finally the prototype is tested in actual rain conditions and an improvement of 6.84% is recorded.