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Gravity Lamp Grabs Green Prize
eldavojohn writes "A lamp powered by gravity has won the second prize at the Greener Gadgets Conference in NYC. From the article, "The light output will be 600-800 lumens — roughly equal to a 40-watt incandescent bulb over a period of four hours. To "turn on" the lamp, the user moves weights from the bottom to the top of the lamp. An hour glass-like mechanism is turned over and the weights are placed in the mass sled near the top of the lamp. The sled begins its gentle glide back down and, within a few seconds, the LEDs come on and light the lamp ... Moulton estimates that Gravia's mechanisms will last more than 200 years, if used eight hours a day, 365 days a year." The article contains links to the patents and the designer/inventor Clay Moulton's site." I think my laptop would require a slightly larger weight to pull this off.
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To say that it runs on potential energy? The device always *has* gravity, but it's not drawing it off. Once you supply the device with some potential energy though, it takes that energy and utilizes it.
I guess "Potentia" isn't as marketable a name, though.
how long before the home gym captures energy for your home.
:-)
Never
Humans can not produce large amounts of sustained output power, even when exercising. A "healthy human" can probably push out 300W for about 20 minutes before they collapse from exhaustion. Even if you can convert all of that to electricity and store it for later use at something like 50% efficiency (which would be staggeringly high), you're only talking about 0.05kWh of usable energy. You could do much better if you were willing to exercise at much lower intensity for much much longer periods of time (but who would do that just to light a minuscule handful of light bulbs). But you're really not going to ever get usable amounts of power out of your daily exercise routine.
He might not, but from what I gather, it's something like this:
PGE = m*g*h (potential gravitational energy in joules = mass * gravity * height)
50 lbs = 22.7 kg
PGE = 22.7 * 9.81 * 1.5 (I'm assuming a generous height of about 1.5 meters here, based on his diagram which gives 58" as the height)
PGE = about 334 joules
A joules is one watt-second, so 334 joules means 334 watts for one second, or 1 watt for 334 seconds.
According to Wikipedia, "The highest efficiency high-power white LED is claimed by Philips Lumileds Lighting Co. with a luminous efficacy of 115 lm/W (350 mA)." The claims is that this light can produce 600-800 lumens. If we take the lower number, 600, that breaks down to about 5 1-watt super-efficient LEDs to produce about 600 lumens.
So that's 5 watts per second, which with energy of 334 joules yields about 66 seconds of output. A far cry from 14,400 seconds (four hours).
Feel free to correct my math, it's been years since I've taken physics.
"Anyone who [rips a CD] is probably engaging in copyright infringement." - David O. Carson
Wow... I'm sure you meant well, but as a VT grad that post comes off as very condescending. To myself and tens of thousands of other hokies, Virginia Tech is not just another descriptor for massacre. There are tons of great things about Virginia Tech that we would much rather be associated with than the tragic shooting. I understand that it will always be a part of our history and it's not something that should be forgotten, but it's not necessary to bring it up every time we make the news (which happens often because there's tons of cool research going on in Blacksburg, VA).
The idea sounds good to me too, but 50lbs. sounds like too much to put at the top of a lamp. I have young kids, and I don't want them getting crushed when they knock this thing over (as they almost certainly will). In addition, a lamp that requires 50lbs. of anything doesn't sound green on the construction side.
Yeah, but if they had any sense, they'd have used cows, or they could have just pithed the humans; they don't WANT them thinking, they just need the meat bags.
either I'm having to lift 10 pounds 5 times every time I want to light the lamp, or I'm lifting 50 pounds.
Unless you are weakened by some medical condition lifting 10 pounds, 4 feet, 5 times in a row, every four waking hours isn't enough of a demand to be an issue. On the contrary I think this regular weight bearing movement might be a very good thing for the elderly or physically frail.This could be viewed as an in-home several-times-a-day physical therapy light. Maybe a moveable stop, which could allow for the weight to start higher off the floor, but would need to be rest more often would be good addition for those with bad backs or knees that can't reach low to the ground. But to force people to get off the couch every two to four hours and move a few ten pound weights can really only be a benefit for the majority of the western world.
We are all just people.
Ok, what the hell. Exactly what kind of worthless prize or conference is this, that they didn't check to see that you need 1000 times the energy the weight could possibly provide? And exactly what kind of scientist designed this thing that can't possibly work?
Meanwhile they're talking about how it would last two hundred years. Right. That's what they spent thier time with, trying to find a way to convince people how incredibly green this thing is.
I hate this sort of environmentalism that has absolutely no regard for reality. This one has no regard for basic conservation of energy, they might as well have said we can solve the energy problem with perpetual motion.
Everything seemed to be going so nice
'till the end of all beings punched right through the ice
Simply building and shipping the 50 pound thing will probably consume more energy than it saves in its entire life. You are better off simply buying a high efficiency LED screw in bulb which are available right now for much less and do work.
I think you have a parse error:
The design goal of Gravia is to provide light in a room (600-800 lumens — roughly equal to one 40 watt incandescent lightbulb), over a period of 4 hours, using people to generate power.
Note the parentheses. It really does say the goal is to light a room over a period of 4 hours.
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Another benefit is that scrap metal and rocks could be utilized as the weights -- IOW junk that's already "energy paid-for" rather than needing to be manufactured afresh, like spring steel.
As to the people whining about how it's too much work to move the weights... check your waistlines. 'Nuf said!!
~REZ~ #43301. Who'd fake being me anyway?
Sure, if you want the lamp to run for 4 minutes instead of 4 hours.
Watt is newton per second, not newton per minute. You forgot a divide by 60.
If J.K.R wrote Windows: Puteulanus fenestra mortalis!
Um, gears aren't magical engery-creation devices. Gears are useful if you have a surplus of torque and want to transform it into rotational speed, or surplus of rotational speed into torque, but you still only get out of it what you put into it. In the case of the mythical lamp, the motion would be multipled by 160 but the apparent weight would be divided by 160, for the same net energy production.