LED Umbrella Is Powered by Rain
by Eric Leech, New York, NY on 12.29.08
Photo credit I'mClaude
Part of creating the ultimate sustainable planet will be our ability to find sustainable energy sources in a variety of means, such as sunlight, water flow, wind, and yes, even rain. We are of course speaking of the kinetic energy which can be harnessed from rain, which up until a few months ago, was not being considered for use in a consumer product...
Lightdrops Umbrella
This kinetic energy is created from piezoelectric material, which is able to convert mechanical energy into electrical energy. Now, we aren't talking about a whole lot of energy being created here, approximately 1 microwatt to 12 milliwatts per rain droplet. While not much in the large scheme of things, this technology has been put to use in a new LED umbrella called Lightdrops, which is able to self power an internal LED light using the rain from which it is protecting its user from.
While a lighted umbrella is certainly not going to save the world by any means, it may save a few lives. The idea behind the umbrella is to provide light in front of the user as well as make the user more visible to traffic in harsh weather. But the most exciting aspect of this products unveiling, is the other possibilities that such a technology may someday provide.
Technology behind the Lightdrops Umbrella
The technology relies on polyvinylidene fluoride (PDVF), which is a flexible, conductive, waterproof membrane that is able to harness the energy of the water droplets without breaking down. Initially, zinc oxide was used on the fabric of t-shirts to collect the kinetic energy from the wearer during their daily activities. The only problem was that the zinc oxide was found to disintegrate when it came in contact with water, which limited its use significantly (rain, washing, sweating, etc).
Piezoelectric technology is still in its early stages, but its promise of future sustainable energy to come is quite exciting. Imagine one day a vehicle, home, or business which will not only be taking advantage of the sun and the wind, but also the occasional rainstorm. This could be the end of rainy day blues as we know it!
More on kinetic energy
Charge Your Gadgets with Small-Scale Renewable Energy
No Shortage of Alternative Energy Innovations at West Coast Green 2008
Time Warp: Energy and Free Running
PVDF is an extremely energy intensive substance to make, and requires extensive amounts of the highly toxic hydrogen fluoride to manufacture. Therefore, it makes the most sense to incorporate such a material in designs where energy is being continuously harvested and where design life is likely to measured in decades, not in months or years (how long do your umbrellas last?).
An umbrella sits in the closet or a brief case for most of its life, making this a very poor application indeed.
A far more useful application would be on a steel building envelope, where PVDF is already widely used as an architectural coating! There it would harvest energy from rain, wind turbulence, vibrations from street noise and building sway - 24/7.
The trick is to find something useful and economic to do with the power generated from a PVDF application. In that we are only limited by an architect's imagination.
"1 microwatt to 12 milliwatts per rain droplet."
Not bad. Multiply that by the 10 million rain droplets that would fall on your roof in an hour, then put it on every roof in Vancouver, where solar panels are pretty much useless 8 months out of the year. Sounds like a winner to me.
Why not just use the generators found in the "shake it to charge" flashlights?
They can obviously power up a pretty bright LED.