Piezoelectric is a device that can harvest energy in the form of electricity when it experiences deflection, and can also change dimensions due to changes in pressure or tensile force experienced by the piezoelectric. The small and thin dimensions of the piezoelectric cause a small deflection produced by the piezoelectric, which is the weakness of the piezoelectric. The purpose of this study is to determine the amount of potential electrical energy generated by energy harvesters with a hybrid system of mini windmills and also piezoelectric. This research was carried out using a real method, in a wind tunnel which was fitted with a bluff body with an angle, as well as mini windmill blades which were fitted with rubber (rubber) as a contact area to cause collisions on the piezoelectric which was covered with fins. The independent variables in this study were wind inlet angles of 40°, 50° and 60° and wind speeds of 6 m/s, 7 m/s and 8m/s. Piezoelectric and mini windmills are installed in a wind tunnel with a bluff body that forms an inlet angle of 40° equipped with a rectifier and a capacitor as a temporary current storage. Electrical energy measurement uses a data acquisition system, namely DATAQ, and is carried out for 60 seconds on testing AC currents and also DC currents. The results of the highest voltage test were on the AC current method using an angle of 40°, and 6 mm fins with a 0.5 mm blade. The wind speed was 8 m/s, which was 12.67 volts. And the test results obtained the highest voltage in the DC current method, which is 11.44 volts. Wind speed, tunnel angle, contact area blades on the windmill and the dimensions of the fins greatly affect the voltage generated by this energy harvesting device.The smaller the wind speed angle which is affected by the wider corner walls of the tunnel, thus making the collision between the fin and the blade hit the contact area as a whole and making the deflection produced by the fin stronger.
Keywords: Hybrid system energy harvester, Piezoelectric, rectifier, rubber, angle