Thursday, February 14, 2008

Raindrops Keep Falling on My PVDF Membrane

Originally posted Feb. 12, 2008 on CleanTechnica

French researchers are trying to develop a way to get electricity from rain, claiming the mechanical energy of raindrops could be enough to power low-energy devices.

It’s not exactly as sexy as harnessing that big ball of fire in the sky or a towering wind turbine. But a clean, 21st century energy system means trying to get energy out of pretty much anything. According to Discovery News, here’s how the rain power could work:

The method relies on a plastic called PVDF (for polyvinylidene difluoride), which is used in a range of products from pipes, films, and wire insulators to high-end paints for metal. PVDF has the unusual property of piezoelectricity, which means it can produce a charge when it’s mechanically deformed.

[Researchers] embedded electrodes into a thin membrane of PVDF, just 25 micrometers thick (it takes 1,000 micrometers to make one millimeter). Then they bombarded the sheet with drops of water varying in diameter from 1 to 5 mm.

As the drops hit the material, they create vibrations, which creates a charge. The electrodes recover the charge for use as power.

The biggest raindrops make the biggest vibrations, and the research team can make at least 1 microwatt of continuous power with the largest drops so far. It’s too early to say now whether we’ll be able to get stable electricity from rainshowers, it’s great that there are researchers like these who think outside the box. (Cloud power, anyone?)

Discovery News
Photo credit: Malene Thyssen

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