The aim of this study is to examine how small amounts of ambient energy, such as in vibrations or wind flow, can be converted to electrical energy and to build a working design.
The different energy harvesting principles found in literature are studied first. Piezoelectric energy harvesting was found suitable for both energy harvesting out of ambient vibrations and wind flow. A cantilevered beam setup with a piezopatch (MFC patch) is chosen because it has good power conversion characteristics, it is robust and versatile. Both vibration and wind flow harvesting devices can be constructed with this setup.
Vibration harvesting setups were constructed with both a commercially available bimorph piezoceramic harvester and with an unimorph harvester consisting of a stainless steel plate and a composite-reinforced piezoceramic patch attached to it. The power output is reported. The parameters that are of importance to optimize the setup are discussed.
The possibilities to use the beam for wind flow harvesting were explored. Different aeroelastic phenomena were studied to give insight into possible working principles. A number of designs are proposed and some are tested using the stainless steel plate with the MFC patch. The possibility of using aeroelastic stability to harvest energy is shown, and suggestions for further improvements are given.