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.

A patent?

[Trailer Trash]

How is this any different than a clock powered by weights? It's nice, but hardly a new idea.

Bending Space-Time Lights the Way

[MSTCrow5429]

"The acrylic lens will be altered by time in an attractive fashion, Moulton said. "The LEDs produce a slightly unnatural blue-ish light. As the acrylic ages, it becomes slightly yellowed and crazed through exposure to ultraviolet light," he said. "The yellowing and crazing will tend to mitigate the unnatural blue hue of the LED light. Thus, Gravia will produce a more natural color of light with age."

He predicted that the acrylic will begin to yellow within 10 to 15 years when Gravia is used in a home's interior room.

Why would I buy a product that takes 10-15 years to become tolerable for normal household use, when in 10-15 years, either this technology will be updated so that it comes with natural light out of the box, or new competing technologies develop that do the same thing, without the color drawback?

Wouldn't it be more accurate...

[Zebraheaded]

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.

Re:Home Gym..

[krlynch]

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 [ohiou.edu] 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.

Re:green? I don't think that word means what you..

[FinestLittleSpace]

"So this idea may be useful in 3rd world countries where power grids are not available."

Ranting for no good cause. That's EXACTLY where it is aimed at, anyway. May I also point out that lifting those weights is not going to produce signficant enegy usage that someone is going to have to change their diet in the richer parts of the world. Don't forget that one of the biggest problems in the wealthy world is OVER eating not undereating!

Re:Looks cool...

[CarAnalogy]

*woosh*

He might not, but here's my work

[langelgjm]

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.

Re:But who is going to control

[learningtree]

No. If you actually observe closely, it is the muscular energy that is expended in lifting the weights to the top of the lamp. The same energy is then converted into light by the falling weights. Considering 100% efficiency, and assuming the lamp to be perpendicular to the earth's surface, the angular velocity of the earth should decrease very slightly. But it will be restored back once the weights fall to the bottom of the lamp, thereby conserving the angular momentum.

Re:It's nice to see good news from Virginia Tech

[vtscott]

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).

Re:Looks cool...

[s_p_oneil]

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.

Re:Hmmm. What else falls around the house?

[wall0159]

I reckon if you're going to try and do that kind of thing anywhere, you should put regenerative braking on your car

Re:Alas

[jridley]

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.

Re:Looks cool...

[Original Replica]

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. [familydoctor.org]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.

Re:It can't possibly work either

[Jonas the Bold]

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.

Waste of time and money

[llZENll]

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.

Re:Looks cool...

[Jerf]

In addition, a lamp that requires 50lbs. of anything doesn't sound green on the construction side.

Which just goes to show how little you should trust your intuition or feelings when it comes to true environmentalism.

We live on a 13,170,856,500,000,000,000,000,000 pound rock. Are you sure that 50 pounds of mass is going to break Gaia?

50 pounds of something in particular could be an environmental problem. 50 pounds of mercury would be horrible. But just "50 pounds" is nothing. Personally, I'd love to have this lamp shipped to me without any weights at all, and I'll just scrounge up the requisite 50lbs of mass. Maybe just ship it with some buckets to hold rocks or sand or dirt; I've got all of the above in abundence. Better than shipping 50 pounds around, which even without analyzing the environmental impact, is going to cost me $$$.

Re:Conservation of Energy

[Nigel Stepp]

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.

Re:Reading for everyone

[sunking2]

What he means is to confuse people into thinking that the product does something that it doesn't, without lying. The write up is clearly meant for people to fall into the trap that many people did, thinking that this thing is a 40 watt lamp replacement that runs for 4 hours. The wording is very deliberate. It's there to generate buzz for something that isn't really worthy of it in hopes to grab some venture capitol.

Re:Why not use a spring?

[Reziac]

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!!

Re:Why not use a spring?

[cuantar]

Why not let the counterweight do work as well? Suppose you have a contraption with two equal mass carts, into which you can place a driving mass. When the heavier cart reaches the bottom, you simply take the mass out and place it in the cart at the top. The machine then functions much like an hourglass, and has a certain symmetry to it that I would call attractive.

Re:You are way, way off

[LarsG]

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.

Re:Gear ratios, people...

[MMORG]

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.