Scientists from Nanyang Technological University, Singapore (NTU Singapore) have developed a low-cost device that can harness energy from wind as gentle as a light breeze and store it as electricity.
This newly-developed device can produce a voltage of three volts and generate electricity of up to 290 microwatts when exposed to winds with a velocity as low as two meters per second (m/s). This is enough to power a commercial sensor device and for it to also send the data to a mobile phone or a computer.
Called a wind harvester, the light and durable device also diverts any electricity that is not in use to a battery, where it can be stored to power devices in the absence of wind. Measuring 15cm by 20cm, the NTU team said the device can easily be mounted on the sides of buildings and would be ideal for urban environments, such as Singaporean suburbs, where average wind speeds are less than 2.5 m/s, outside of thunderstorms.
The wind harvester’s body is made of fiber epoxy, a highly durable polymer, with the main attachment that interacts with the wind and is made of inexpensive materials, such as copper, aluminum foil, and polytetrafluoroethylene, a durable polymer that is also known as Teflon. When the harvester is exposed to wind flow, it begins to vibrate, causing its plate to approach and depart from the stopper. This causes charges to be formed on the film, and an electrical current is formed as they flow from the aluminum foil to the copper film.
In laboratory tests, the NTU-developed wind harvester could power 40 LEDs consistently at a wind speed of 4 m/s. It could also trigger a sensor device and power it sufficiently to send the room temperature information to a mobile phone wirelessly.
The researchers claim their invention has the e potential to replace batteries in powering light-emitting diode (LED) lights and structural health monitoring sensors. These are used to monitor their structural health, alerting engineers to issues such as instabilities or physical damage to metropolitan constructions like skyscrapers and bridges.
“As a renewable and clean energy source, wind power generation has attracted extensive research attention,” said Professor Yang Yaowen, who led the project. “Our research aims to tackle the lack of a small-scale energy harvester for more targeted functions, such as to power smaller sensors and electronic devices. The device we developed also serves as a potential alternative to smaller lithium-ion batteries, as our wind harvester is self-sufficient and would only require occasional maintenance, and does not use heavy metals, which, if not disposed of properly, could cause environmental problems.”
The NTU team is now working on improving the energy storage functions of their device, as well as experimenting with different materials to improve its output power.
- Chaoyang Zhao, Guobiao Hu, Yaowen Yang. A cantilever-type vibro-impact triboelectric energy harvester for wind energy harvesting. Mechanical Systems and Signal Processing, 2022; 177: 109185. DOI: 10.1016/j.ymssp.2022.109185