Experimental Testing of a Piezoaeroelastic Energy Harvester in a Wind Tunnel

Open Access
Author:
Fobben, Gregory
Area of Honors:
Mechanical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Christopher Rahn, Thesis Supervisor
  • Hosam Kadry Fathy, Honors Advisor
Keywords:
  • Energy Harvester
  • Piezoelectric
  • Aeroelastic
  • Piezoaeroelastic
Abstract:
Aeroelastic energy harvesting in Heating, Ventilation, and Air Conditioning (HVAC) ducts has the potential to provide buildings with wireless security, air quality, temperature, and humidity monitoring. The energy generated could power a sensor, an on-board microprocessor, and Wi-Fi communications without the need for power and communication wiring. The sensor could work for years without the need for maintenance (e.g. battery changing). This work investigates the effect that certain variables have on the power and voltage output of a piezoelectric energy harvester that is placed in a wind tunnel. The harvester uses a unimorph cantilever that consists of a layer of piezoelectric material, PVDF, and a base material, Mylar. The cantilever is mounted on the face of a box that is perpendicular to the flow of the wind in the tunnel, and the air is allowed to pass through small gaps around the cantilever of varying widths, causing the cantilever to vibrate. The experiment demonstrates the effect that this gap width, the wind speed, and the applied load resistance has on the amount of power and voltage that the energy harvester can generate. Analysis of the collected data suggests that power and voltage increase with increasing gap width. Realistically, power would not continue to rise as gap size continued to grow, as there would be an optimal value for gap width. Optimization of gap width, however, is not within the scope of this thesis. There is also a clear trend of power and voltage increase as wind speed and electrical load resistance increase. The experiments test power and voltage outputs for 8 wind speeds, 3 load resistances, and 3 gap widths. Further experimentation should include additional load resistances and at least one gap width larger than 5 mm to verify the trends that are observed in this thesis.