Lightdrops Umbrella is Powered by Rain
Anyone who has been caught in a torrential downpour knows that rain can be pretty powerful stuff. That’s why the Lightdrops umbrella prototype is so ingenious. The polyvinylidene fluoride (PVDF) umbrella features a “collective membrane” that powers its LED lights with energy from the rain.
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The PVDF material actually harvests kinetic energy— the heavier the rain, the brighter the umbrella’s LED light becomes.
Designer Sang-Kyun Park’s umbrella isn’t close to being released yet, but I’ll be first in line for the finished product.
Photo Credit: Sang-Kyun Park
Oh no, calling all units, we have a Class A Wankware offense here!
You are guilty of the following crimes:
*Posting pictures and text describing a product that disobeys the laws of physics.
Explanation:
Let’s estimate this umbrella of having a 4 foot diameter. That works out to a 60cm radius and an area of about 11,300 square centimeters. Oh an extremely bad night, you might have 10 inches of rain which falls over several hours. 10 inches of rain is 25.4 centimeters which works out to (25.4*11,300=) 282,743 cubic centimeters of water or about 282liters of water.
Assuming it’s fresh water, that means 282kg of water. Extremely fast falling rain has a velocity of about 18mph or 8meters per second. The kinetic energy of that body of rain would then be (.5 x 282 x 8^2=) 9,024 joules of energy spread out over the entire night.
By comparison, a single AA can put out 2.89amp/hours of current at 1.5 volts which works out to (2.89 x 1.5 x 3600=) 15,606 Joules of energy. So by standing in the rain for several hours, you would accumulate the energy of half a AA battery.
To get the brightness indicated in this picture, you would probably need ten or so high power LEDs which would use about .6 watts. Assuming your torrential downpour dumped its 10 inches of rain in just five hours means your power output from the umbrella is (9024/(5*3600=) .5 watts. This falls just short of the .6 watt mark.
Granted, it seems to come pretty close to reasonable, but this is assuming that you have 1/4th of Seattle’s yearly precipitation fall in 5 hours and perfect energy conversion. This is enough to warrant a Wankware arrest.
*Posting pictures and descriptions of products with pointless features
Explanation: A single AA battery or even harnessing wind power would make this product much more practical.
You will be contacted to schedule a court date.
I’d have to see it to believe it. Seems like it’d be hard to get a lot of power from rain like that. A bazillion times easier to stick a battery in there that’s charged from opening and closing the umbrella.
This could be applied to all weather tent, which would provide a much larger surface area…maybe enough to charge up some batteries since it would be pretty difficult to get solar energy in a rainstorm.
it’s piezoelectric, numpty !