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.

The demand for energy-harvesting technology is steadily growing in the field of self-powered wireless sensor systems for use in pneumatic systems. The purpose of this research was to study an energy harvester excited by alternating air load in a pneumatic system. The harvester was designed to consist of a power chamber and a compressed chamber, and to the bottom of the power chamber a piezoelectric patch as been affixed. The harvester is excited by the changing pressure, which can be adjusted through changing volume, and the alternating air pressure energy can be harvested through the deformation of the piezoelectric patch. A test system was built and a prototype device was tested under various experimental conditions. The test results show that the energy generation performance of the harvester can be influenced by varying the volume compression parameters, with the output voltage increasing when the flow increases. The maximal output voltage and power are 24.7 V and 1.06 mW, respectively. An effective power of 0.28 mW was measured across the 200 kΩ resistor at a pressure of 200 kPa and a cycle time of 2.5 s with a flow of 150 L/min.