Human power idea #2

[tmpcbtc]

You may recall that Conan the Barbarian got his muscles by pushing a large wooden wheel around for years.

Yes, I actually got this idea somewhat from that Conan scene 

The problem with getting power from the public without paying them for it is just as people were saying.
If you use water pressure in pipes for power, then you will most likely have lower water pressure in your home. Similarly, if you hook up revolving doors to generators, those doors are gonna be really hard to push!
Two MIT students had the idea of putting spring loaded tiles in subway stations to convert the kinetic energy of foot traffic into electricity, but some guy got really upset about the idea...He compared it to little leeches leaching the energy you get from food, so you would have to eat more when you got home...

[tmpcbtc]

Saying something generates so many Kilowatts in a certain number of minutes doesn't make any sense. Kilowatts is a measure of power. Power accrued over time is energy, which is measured in Kilowatt hours. Human powered generators are not a new idea. They have been done.

I mentioned that 5 people could generate 1 Kilowatt  in 45 minutes, so that's what 1 1/3 kilowatts in one hour? Same thing :p
If you can store that energy in batteries then time only comes into play when you say "Is it worth it to spend 8 hours a day turning a wheel to power my house? No. Is it worth it to spend 1 hour turning a wheel to power my house for two days? Maybe..."

NOTE: I just read on another post that an average house takes 10-20Kilowatt/hours per day to run. So that would take at least 50 people each on a bicycle to generate enough for a house all day every day. But bicycle generators are geared in a way that it takes a lot of muscle power just to induce one revolution of the generator wheel. With a big wheel geared down to a smaller wheel, you get many many many more revolutions in the smaller wheel/generator for not as much physical energy expended so the energy of those 50 people could do a hell of a lot more.

[tmpcbtc]

I thought you gained torque when gearing down? Torque = force times the length of a lever, so the longer the lever, the greater the torque. In this case the lever length would be dependent on the size of the larger wheel, the larger the larger wheel, the greater the torque applied to the generator wheel.
Right?

[utilitarian]

I thought you gained torque when gearing down? Torque = force times the length of a lever, so the longer the lever, the greater the torque. In this case the lever length would be dependent on the size of the larger wheel, the larger the larger wheel, the greater the torque applied to the generator wheel.
Right?

Maybe Nomen Luni did not make it clear enough.  You cannot just start generating more power by changing the gearing.  It just makes the wheel easier or harder to crank, but it all balances out.  With a low gear (easy to turn the crank), the cyclist can pedal easily, but has to make more revolutions to generate the same amount of power that a higher gear would require.  So all you gain is mechanical advantage - you cannot actually make the process more or less efficient by using gears (aside from the loss of efficiency involved with more moving parts).

Try riding a bicycle (a real one, not stationary) and you will see what I mean.

[tmpcbtc]

So all you gain is mechanical advantage - you cannot actually make the process more or less efficient by using gears (aside from the loss of efficiency involved with more moving parts).

That's exactly what I mean though.
If you took a one megawatt generator and hooked it up to a large enough wheel, even the force of one person pushing the (VERY large) wheel would be able to spin the generator at optimal speed (to generate 1 megawatt constantly).
It is the same principle as a one megawatt wind turbine, which revolves very slowly, but generates 1 megawatt constantly. This idea is essentially just taking a wind turbine and laying it down on the ground, and having it pushed by people instead of the wind. (But with a wheel most likely of much larger diameter than the circle made by wind turbine blades)