Rain-driven impulse turbine for vibration-based energy harvesting using piezoelectric transducer

This paper presents a rain-driven impulse turbine for vibration-based energy harvester using piezoelectric transducers to scavenge rainfall energy into electrical energy. The system employs a funnel-based rain collection mechanism, directing water through a 36 cm pipe to rotate a specially designed turbine. The turbine’s central shaft drives a rotating disk with an impact pin, which strikes a cantilever beam, generating mechanical vibrations. These impulses induce mechanical vibrations, which are converted into electrical energy using piezoelectric transducers. The mechanical configuration was optimized to match the beam’s resonance frequency, thereby improving vibration amplitude and energy conversion. Experiments tested the minimum rainfall required for turbine activation by pouring 80–1000 ml of water from 66 cm above the blades. A rain simulation setup pumped water from a reservoir to simulate heavy rainfall conditions, with greater rainfall intensity or larger funnel surface area improving turbine flow. The harvested AC signal from multiple piezoelectric transducers was rectified into DC and used to charge a supercapacitor, achieving near-full charge in 15 min and sustaining a 3-h operation of a low-power load. The discharged rainwater generates a substantial flow through the pipe, enabling the water turbine to operate effectively over multiple cycles within a short duration, thereby increasing the amount of energy accumulated. The results confirm the system’s mechanical feasibility and demonstrate that impulse-induced resonance offers a practical mechanism for harnessing rainfall energy in remote or off-grid environments. This work highlights a mechanically robust alternative to direct raindrop impact or surface-mounted harvesters.