Development of Vibration-Based Piezoelectric Raindrop Energy Harvesting System

The trend of finding new means to harvest energy has triggered numerous researches to explore the potential of raindrop energy harvesting. This paper presents an investigation on raindrop energy harvesting which compares the performance of polyvinylidene fluoride (PVDF) cantilever and bridge structure transducers and the development of a raindrop energy harvesting system. The parameters which contribute to the output voltage such as droplet size, droplets released at specific heights and dimensions of PVDF transducers are analyzed. Based on the experimental results, the outcomes have shown that the bridge structure transducer generated a higher voltage than the cantilever. Several dimensions have been tested and it was found that the 30 mm x 4 mm x 25 mu m bridge structure transducer generated a relatively high AC open-circuit voltage, which is 4.22 V. The power generated by the bridge transducer is 18 mu W across a load of 330 k Omega. The transducer is able to drive up a standard alternative current (AC) to direct current (DC) converter (full-wave bridge rectifier). It generated a DC voltage, V (DC) of 8.7 mV and 229 pW across a 330 k Omega resistor per drop. It is also capable to generate 9.3 nJ in 20 s from an actual rain event.