any engineers here?

[tabbycat31]

If anyone's good with that kind of stuff, I have a very good entrepreneurial activity for you. I was at the gym today when we lost power. My gym has over 100 cardio machines (treadmills, stationary bikes, eliptical machines, rowing machines) that could probably generate enough power to power the gym, and we would not lose power like that.

I don't have the scientific knowlege to put it together, but it could be a great business opportunity for the right person.

[s-cubed]

1. Roughly speaking, someone on a stationary bike can power a light bulb.

Yes, you could be some power out of all those machines, but you'd need some equipment to store power and to modulate the highly varying load. I wouldn't count on it as a real money maker.

[RamboLiberal]

2. Too late - someone has already done this

Boesel's handful of elliptical trainers, treadmills and exercise bikes are all retrofitted with flywheels or resistors that use their own spinning action to charge up a big portable battery — which can then be used to power the Green Microgym's lights, TVs or stereo system — or feed power back into a wall socket.

Boesel worked with the Energy Trust of Oregon to install "net metering" technology that allows the Green Microgym to deliver electricity back to the local power grid and get credit for it. (Net metering is available in Clark County; visit www.clarkpublicutilities.com).

The Green Microgym offers a "burn and earn" program to benefit members for the power they generate — or, rather, for the time they spend generating power. They keep track of that time on punch cards — it's an honor system — and for every 10 hours completed, they get $10 vouchers for neighborhood businesses including cafes and wine bars.

"What other gym can you join where you get in shape, power the CD player and make power to make money to use in the neighborhood?" Boesel said.

http://columbian.com/article/20090216/NEWS02/702169966

http://www.nytimes.com/2008/09/25/fashion/25gym.html

[ColbertWatcher]

4. Is that like what Ed Begley, Jr. did on his show? (EDITED W/BETTER LINK)

http://www.livingwithed.net/energy.asp?target=33

[doc03]

5. I spend about 10 hours a month

on the machines and it would reduce my cost of membership by $10, sounds great to me. It would even encourage people to exercise more.

[OPERATIONMINDCRIME]

8. I'm Amazed That Exists. I Say That Because I Thought Of Roughly The Exact Same Idea Last Year.

Didn't know at the time it already existed; but I wanted to make very much the same thing, in a method that could be relayed back to a regular household circuit where the electricity generated would be used before the regular current was used again. Was more complicated than that with many other concepts than just the exercise bike, but roughly the concept was exactly the same. I'm in awe that someone actually did it and it works like that!

It basically is just a simple notion of rotation being able to generate current (or any manual movement really). What I wanted to also do was have the new york city subway, disney world, etc all fitted with generator type turnstyles, so that EVERY crank of the turnstyle would generate a small amount of current. Multiply that by the countless thousands of turns and you've got some good current. This could then be used to power other things in the facility etc. I also wanted to incorporate the same into a cool crank handle found here and there. Bored people, people with fixations, or just green minded people could just give the crank a few whirls as they walk by, wait, whatever. These cranks could be on found in any major metropolitan area, and if 'marketed' right I'm sure would draw attention have yield countless thousands of cranks per day, just 'because'. Kinda hard to get the idea across as it is in my head, but I'm sure you've got the basic gist.

Anyway, fascinating stuff! Don't believe that gym exists!

[soothsayer]

9. This guy with the sailor's hat?

[doc03]

3. I'm not an engineer but I think many of the machines

use the electrical energy generated by the user to provide the resistance on the machine. Good question though, maybe they could use excess power to charge batteries that would take over in a power failure. My brother has a bank of lift truck batteries he has on a trickle charger and when he has a power failure they can power critical things in his house for several hours from the stored energy.

[BobRossi]

6. I have thought about that for years.

As the previous poster stated, one person can produce about enough power to light a 100 watt light bulb, not very efficiant for powering an operation like a gym.

People power could by used, and actually is used to help heat the gym. (Excess body heat).
Some excessive equipment creates resistance by turning a generator that dumps it's power into resistors, the resistors give up this energy in the form of heat.

It is quite surprising just how much work is required to light a 100 watt light bulb, the next time you are at a hands-on museum look for the hand-crank generator connected to the light bulb and give it a try.

[uppityperson]

7. Pre and grade school playground equipment.

Figure out some way to have safe moving things and I bet you could power the whole school off 1 recess. Kid "hamster balls"?