"Crowd Farm" to Collect Energy?

Cain writes to mention that a couple of MIT students would like to harness the mechanical power of large groups of people. "A Crowd Farm in Boston's South Station railway terminal would work like this: A responsive sub-flooring system made up of blocks that depress slightly under the force of human steps would be installed beneath the station's main lobby. The slippage of the blocks against one another as people walked would generate power through the principle of the dynamo, a device that converts the energy of motion into that of an electric current."

Re:The people power the city huh?

[morari]

The electric company is already to obligated to pay for any excess power you would happen to generate. Add that fact on top of not having an electric bill and the waterwheel that I installed starts to look pretty nifty.

School Science

[Timberwolf0122]

Ages ago in a sceince lesson we were asked to analyse the idea of pulling rollers on the M25 motorway to capture the energy of vehicles that ran over them, well I sort of spotted the flaw in the plan being that the car would all get sucky MPG and polute more.

Now one decade later we have the same idea but with people, howmuch polution will that produce (though extra repiration)? also would not the capture of all the excess heat produced by said people to heat say water (save money on heating by getting the water from 10C to day 20->30C and reduce the strain on the A/C by lowering the Air temp+humidity) be better?

Already Done (kind of) in Britain

[KermodeBear]

I believe that I saw an article on Slashdot several months ago where this kind of idea was implemented in Britain, but it was on the roads. Cars getting onto the highways would drive over large plates; the plates would move and generate enough electricity to run street lights. Not a bad idea, but I wonder if the energy return in this case would be enough to justify the cost of installation.

Re:A better idea

[reddburn]

Some company in denmark is working on dance clubs that would work in a similar fashion (lights and volume powered by the activity on the dance floor). They debuted a working prototype of the floor (10 meters square) at the Live Earth concert. I just heard about it, but it sounds similar: http://www.sustainabledanceclub.com/ [sustainabledanceclub.com]

Re:Rock concerts

[Radon360]

Well, that would make a rather nice positive (yet self-limiting) feedback loop. If the band sucks, the music stops (or at least gets quieter). You still need to get it going. Do you give the band a limited capacitive jumpstart to get the crowd going or do you wait until the crowd starts chanting and stomping their feet to get the show going?

I would do it differently

[Orleron]

Instead of making a surface where people depress some kind of dynamo, why not just capture vibrations generated from walking on the floor? That way, you're only using *wasted* energy which is normally dissipated in the form of sound, vibrations, and heat, rather than make people work to walk on a squishy floor.

Re:Wouldn't this make it harder to walk?

[trtmrt]

A lot of comments on this in the thread. Energy is conserved but the question is where does the energy go when you walk on a normal surface. If you have a solid immovable floor the energy you impart onto the surface through friction gets dissipated as heat (slight bending of the material, compacting of the earth...). If you could "dissipate" this energy into electricity it might not be significantly harder to walk on such a surface. Also, if these are just piezos than you are basically just bouncing on what feels like slightly softer surface and I don't see that as a big problem. The practical issues however are a different story (maintenance, efficiency, cost/benefit).

Let's get (somewhat) practical...

[martyb]

FTFS:

"A responsive sub-flooring system made up of blocks that depress slightly under the force of human steps would be installed beneath the station's main lobby.

And when the snow comes in winter, when the floor is wet and/or icy, people will be falling all over the place increasing their energy donation to the system. <sarcasm>grin</sarcasm>

But seriously, just how much would it COST to build, install, and maintain a floor-wide energy absorbing system? May I suggest they put these panels under the stairs, instead? Especially on the stairs going DOWN. Take advantage of the energy of the crowds where the investment is smallest and the payback is the greatest. This could even be developed as an after-market item and installed ANYWHERE, without having to modify existing infrastructure. i.e. place meta-steps on top of the existing steps and then wire the meta-steps together.

Re:One possible drawback

[Anonymous Coward]

The energy has to come from somewhere.

Don't you mean "The energy has to go somewhere." We're talking about wasted energy, here... stuff that joints, bones, muscles and shoe cushions absorb during the impact of ambulation. Wouldn't such a floor be easier on your hips, ankles and knees as it absorbs the energy that would would otherwise be vented out to those tissues?

Re:house music all night long

[Magada]

The calculation is idiotic anyway. Most modern exercise bikes are "magnetic" (i.e. already have a dynamo inside and put some of the energy you generate to work against your very motion) already. One such can be had for under 400 USD.

Won't work -- dumb idea

[Thomasje]

For a straightforward demolition of the concept, see this article at The Register [theregister.co.uk].