Conversion of Wind-Induced Vibrations into Electricity

The recently growing concern to reduce the energy from non-renewable sources encourages the development of new energy harvesting methods. In case of unattended remote telecom equipment, it should be advantageous to obtain energy from the wind while no rotation is applied. In this paper, a study is described on the feasibility of energy harvesting from the wind, not based on turbine but on piezoelectric transducers that convert the wind-induced vibrations of a cantilevered beam elements into electric energy. The main investigated element is the oscillating body placed at the free end of the beam. The prototype was developed in three different arrangements of the beam and the oscillating body. The essential variations were the length of the beam and the size of the oscillatory body. According to the results, a panel occupying one square meter and operating at 10% efficiency in 10 m/s wind might be able to generate 54 W of electric power. Contrary to the intuitive thought, a cantilever beam system completed with an oscillatory body, produces energy proportional to the amplitude of oscillation (directly dependant on the resonant frequency proximity) and not to the derivative of the oscillations. The produced oscillations and electric power depend on the speed of wind. The findings are useful for creating a reliable, efficient wind energy harvesting system, which could be mounted on bridges, buildings, poles and simply on the ground. It is even possible to mount beams of different sizes and constructions in order to be efficient for various wind speeds.