Aeroelastic wind energy harvesting by piezoelectric MEMS device with turbulence capturing

Abstract

Wind tunnel experiments have been conducted to investigate the effect of turbulence on the power output of a MEMS aeroelastic wind energy harvester of approximately 5.5 mm × 5.5 mm × 10 mm in size. The energy harvester consisted mainly of a cylinder (2 mm diameter, 10 mm length) attached to a MEMS platform equipped with piezoelectric. The turbulence is artificially created via a turbulence generator comprising of a series of rectangular beams placed in the wind tunnel upstream of the energy harvester. By varying the wind speed and width of the turbulence generator beams, it is shown that the time-averaged power output of the energy harvester increases significantly as wind speed and turbulence generator size increases. In particular, replacing a 5 mm-width turbulence generator with a 20 mm-width turbulence generator can increase the power output by 1710% at wind speed of 6 m/s. Power output in the magnitude of tens of nanowatts is measured when the device is exposed to turbulent winds. Results suggest that the turbulence capturing concept may be a promising means of harvesting wind energy for miniature Internet-of-Things devices, such as small wireless sensor nodes that are not connected to the power grid.