Science: Energy: Bioenergy: Human
PeopleWheel   (+5, -2)  [vote for, against]
Power from people the easy way

I've always wanted to build a bike machine which creates electricity. I used to wonder why they didn't fill gyms with them, then I realized the cost just didn't cut it, it would take about forty years to pay for itself.

One proposed way to *store* energy was to lift a huge weight up (possibly hanging in a mineshaft) when demand was low, and let it down when demand is high. Pumping water up a dam turns out to be a better way to do it, but the principle is the same.

This idea is to take an old Ferris wheel from a fairground, and an old fire escape from a building (or just a ladder), weld them together and use the motor as a generator. People can climb to the top using their legs very efficiently, and can sit comfortably in a carriage which pulls the wheel around. The low gear ratio means it doesn't need to stop (like many big Ferris wheels) and it should generate about the same as a medium sized wind turbine.

People can be paid by the joule, which is great for the obese, as they get paid more for their exercise. Athletes could carry heavy weights with them to get more out of each trip. Built on an enormous scale, it might take over an hour for a full rotation, so people can socialise/read books/browse the web in their carriage as they're making electricity. It could even be built at the edge of cliffs, so to get to the top, hikers can go for a lovely walk round instead of the boring stairs. You could even cycle your way to the top.

The advantages of course are that it's far cheaper on a per-person basis, it's much more customisable to what method of exercise you want to do, and the large motor and heavy flywheel should mean better efficiency than lots of little machines.

You could also have a similar generation function in skyscrapers, for people who take the stairs up, but take the lift down. But maybe that's more effort than it's worth.
-- mitxela, Apr 01 2009

London Eye http://www.londoney...gFacts/Default.aspx
Look under "slowly but surely" [eight_nine_tortoise, Apr 02 2009]

Sounds good, but the problem with people power is that it's terribly low power, i.e. a top athlete can produce about 400W reliably, more like 200W for a healthy, fit person.

As a green attraction, this sounds good, as a power source, it's gonna be rubbish!

Like the thinking though! Climb the stairs, stand on the scales, collect your ticket, sit back and relax!

100kg person x 100m drop x 9.81m/s2 = 98,100J = 0.02725 kWh x 8p/kWh = 0.218 pence for a run, so 5 trips round would earn each user 1p (assuming the electricity is sold at consumer rates, rather than wholesale, which is much less)!
-- Skrewloose, Apr 01 2009

[Skrewloose] has the numbers to back it up, but the intuitive approach is also quite... intuitive? -> If it isn't profitable to have people straining on a bike to produce energy, any other venue of human energy production will also be unprofitable.
-- loonquawl, Apr 01 2009

[Skrewloose], this is true. I was thinking maybe having little rfid cards you could swipe each time you go on it to save time. If it was like an internet cafe inside, I see no reason you couldn't go on it 10 or more times a day, every day, which would add up. In fact the wifi inside could be free, the price would be climbing the stairs every 15 minutes or so.

If it was just smaller than the London eye, which does a rotation in 30 minutes, at 135 metres, holding 760 people, you could say that 380 people fall 100m every 15 minutes. ( 98,100J * 380 people )/15/60 = 41 420 Watts. Would be less after the inefficiency, but still a respectable amount for people-power.
-- mitxela, Apr 01 2009

As a human powered zero emission cybercafe/gaming centre, it would be pretty cool, but bear in mind you also need to heat the capsules in winter, which is gonna sup most of your power (30kW isn't a lot for heating that amount of space, especially with such a huge surface area).

As an afterthought, if you're gonna have a huge energy producing wheel, could you fit blades and run it as a wind turbine also? Not as efficient as a high turbine, but certainly a huge boost to the people-power.

I'm not saying it's a bad idea (I like it), just that it's not ever gonna be a realistic power source.
-- Skrewloose, Apr 01 2009

Heating/air conditioning is a bit of an issue, yes... Perhaps if several wheels were constructed within reasonable distance from each other, there could be a central climate-control unit which flushes the air in each capsule when it opens at the bottom.

You could attach turbine blades, but it would be pretty difficult to aim the entire wheel in the direction of the wind. Perhaps a small, vertical axis turbine mounted on top of each carriage would be able to provide a small boost in power production.

And no, this isn't realistic as a big power source, but it would be enough of a novelty I think to generate a fair amount as a one-off power source, as a tourist attraction, as an eco-friendly attraction, and as a health-promoting cybercafe.

Don't forget you'd have all the views of a ferris wheel, plus if it was created out of a recycled ferris wheel, that would add to the green-ness of it all.
-- mitxela, Apr 01 2009

//Hasn't this idea been rehashed here hundreds of times?//

In my quick search, I couldn't find anything quite like this.
-- mitxela, Apr 01 2009

I think the concept as an 'ecoride' is brilliant, the problem is that there's no way you're ever gonna have a surplus of energy.

Obviously active aiming of the wheel into the wind is gonna be difficult without a purpose-built base, but my blades would be a passive device more for a cheap additional income of energy if the prevailing wind is in our favour.
-- Skrewloose, Apr 01 2009

If the wheel is in motion, how will one get into the seat as it passes by? Regular ferris wheels stop periodically.
-- bungston, Apr 01 2009

At the top of the stairs there could be a ~10m conveyor belt that you can step on, before grabbing a handle, being pulled alongside the doorway, then stepping in. Admittedly there'd have to be a way round from the end of the conveyor to the start in case you missed your carriage.
-- Skrewloose, Apr 02 2009

Bungston, you need to visit the London Eye. That does not stop to let anyone one and off, even wheelchair users, unless it breaks down.
-- eight_nine_tortoise, Apr 02 2009

Use somewhere with a pre-existing height difference, such as a promenade and a breach, that has a fair amount of traffic across it.
-- Aristotle, Apr 02 2009

random, halfbakery