Design and Testing of Cantilevered PVDF Energy Harvester Based on the Coanda Effect

Low-flow air has been attracted many researchers which can be transformed into electric energy by the piezoelectric materials. A flow amplifier device can be used to increase the performance of piezoelectric energy harvester excited by low-flow air. The Coanda effect theory has been analyzed based on the fast-moving air. To analyze the effect of the amplifier device and verify the feasibility of the proposed cantilevered PVDF energy harvester, we employed finite element simulation to analyze the flow distribution of the amplified flow air. Then the stress and potential distribution of PVDF film have been analyzed. A prototype of the cantilevered PVDF energy harvester is tested with different variables such as input air flow, pressure and cycle time. The test results show that the output voltage increases with increasing input air flow. The output voltage decreases slightly with increasing input cycle time. The peak voltage decreases as the distance between the prototype and the excitation source increases. Importantly, the output voltage for the amplified airflow is about three-times that of the non-amplified air flow. The maximal output voltage and power are 12.80 V and 19.89 μW at the pressure of 0.2 MPa and a flow rate of 200 L/min, respectively.