Human-Powered Generators

[nightwynd]

Had what may be called an epiphany in my imsomniatic sleep last night. Why not use people power to run a generator? Now I know that this has been done before - but only on a small scale. IE: using a bicycle to power a generator, etc. What I'm thinking is using gravity and leverage to create a HUGE mechanical advantage to spin a very large and heavy flywheel, geared up to a generator (was thinking something along the lines of a micro-hydro generator). Now if the gearing is done properly, I can't see why with a little bit of effort, the generator should spin for a full day or so. I'm thinking of something along the lines of an elevator....maybe 3-5 stories high - hook it all up to a transmission that will not let you fall too terribly fast and be enough for a minimum of 200lbs to spin the flywheel. Whip up a second elevator cage so it goes up as you go down - then just climb up a simple staircase and go for another ride - do this 2-4 times and you have your power for the day - and some damn good exercise

anyone have any thoughts on this? Actually, what i would be most interested in, is if anyone has experience setting up gearboxes that would allow an elevator device like this to function....

Thanks!
nighwynd

[hartiberlin]

You would have to climb a lot of stairs.

The formula:
Energy= Mass x Gravityacceleration x Heightdifference
tells it all.

If you have a weight of 100 Kg ( pretty fat !)
and go 10 Meters up you have the potential energy:
100 kg x 10 x 10 Meters= 10.000 Joules= 10.000 Wattseconds= 2.7 Watthours.
This means you can then just light a 2.7 Watts Bulb for 1 Hour with it...
if the conversion to electrical energy would be 100 % efficient...which is not...
climb 100 Meters and you could light a 27 Watts bulb for 1 hour only...

You see, pretty exhausting for a human to generate power this way...

[nightwynd]

well there goes that theory....dang...I would think that you could somehow work in some kind of mechanical advantage to do more work over that distance - I mean, a 200lb weight falling 20 feet has to be able to do some amazing ammounts of work doesn't it?

[hartiberlin]

@nightwynd 
No,
even less than 2.7 Watthours...
Just use the above formula and it tells you all..
This is the maximum available energy from a falling weight.