Generating electricity by workout equipments in Gyms

I have the same idea for quite some time. My idea is like the movie - Monster Inc. - to create electricity tank (battery) to be used may be for houses.

a person at hard exercise puts out 100 watts for extended times. Short burts of 500 watts or more are possible to a few people. lifting and lowering a 550 pound weight by 6" (total travel is one foot ) = 1 HP for that second. I could raise 900 pounds on a leg lift in a second by 2 feet and back, but only for a few seconds, If if cut back to 550 pounds and raies it and lowered it 2 feet every 4 seconds = 1 HP, I could have done that for 30 seconds or less. I used to cycle 60 miles/day, so I had the legs.

Most gyms now have equipment that uses a generator for power of the readouts and a computer to track your performance.

It can be done. The question is why do it for such a trvial amount of electricity. In space this may be worthwhile, but new solar cells that reach the mid 40's in efficiency make even that not worth while.

It has to be a valuable exercise, not just something you can do for no other reason than saying you can do it.

In reply to Aurizon with thanks, this can be a valuable exercises in terms of global warming.

The figures correspond well with a hill-climb exercise on a bicycle, which showed that the at-crank power was of the order of 120W for about 10 minutes, in addition to the 80-120W of body heat released to the environment while cranking.

Most lit gymnasiums have well over 120W/person of artificial illumination.

A sideways glance: most office buildings have individuals dissipating 60-100W/person within them. What could be done with that?

Maybe make everybody use a kind of stirling motor connected to a portable generator and accumulator, could deliver some energy, even if people is at rest completely...

A good point for TV advertising: "AB-thermalex-fat-loss-o-matic". Loose weight while you're watching TV, driving or even sleeping! Convert the fat of your body into energy to charge the batteries (not included) of your camera (not included),for example! Just tie the device around your wrist and head, and let your body temperature do the rest. If you're sick and with fever, even better! A good device for clinics and hospitals, too...

Unfortunately, I do not know any device that could give some amount of energy working with the temperature diference between the human body and the ambient, and be light, weareable, and profitable. MAybe a new matter for development: clothes that convert body temp in electricity.

Sell TVs attached to treadmill generators or exercise bikes, so to keep watching, you must keep working

Hey, good idea.

You could also use the same to power the kitchen, so you need a good amount of effort to heat up food, or to cool down beer.

Or you could give up and go to the bar, see some chicks, drink cold beer, eat some snacks, and proudly give some gentle taps in the paunch!

This deviates from the original post, in that the electricity generated was to do something useful!

200W for a TV plus 100W for lighting? The beat goes on....

LOL, I like the way you seem to think in most of your answers I've read,,,,,,

Me = expert heckler

You 'r god them right!!

two hours of workout equals to 1 hp (746watts of power) ,imaging 50 million people doing that!!! (746x50,000,000/2)x24x365=1.63 megawatts/year, amazing!!!

I spend almost 85 kwhr a day at my shop, that means that i can run free with that energy 1.2 years without expend any money

For those who have seen the Matrix, the human body creates alot of heat.

160 pound man = 100 watts standing still.

goes up with the work you do. brain is 25% of that

Oh, 25 % in the brain active... uh, I think mine, after all this time, may spend something around 10%...

By the way, I received an interesting calculation that proves that you can loose weight drinking cold beers. As it is cold, the body would spend more energy to keep internal temperature than the energy in the beer.

I have already initiated my diet. Let's see what happens....

THe answer is yes, it could be done, and it would be a great idea of how use an ammount of energy that's spent useless every single day (that's why, I think, I could never allow me in a gym, always preferred ride a bike... at least I was moving...). Why it's not done already? I think there will be a great cost on equipment in first step. You need one generator for each device. Then, connect everything to a power central. It would accumulate energy in batteries. Then, this power central can be used to supply power to the building itself through static inverters (high power for aircon). Any exceeding energy could be delivered to the distribution net, selling energy, trhough special inverters and contactors to guarantee adequate voltage and phase coupling. And then, keep everything running smootlhy through the years.

After all, unless there's a jump in energy cost enough, I think it would be difficult to a gym to have the required money to start the system and wait for the payback period. After all, it's all about money. Interesting subject for a marketing and viability analysis. If you can build equipments cheap enough, it would be a great goal.

Gym equipment used in prisons must be so equipped. Prisoners should be made to workout on these machines as a part of thier punishment :-)

Kris

Thats actually a good idea. It costs so much money keeping people in prison might as well try and make a percentage back.

As has been mentioned, the number of watts that a typical bike rider can put out are fairly low. In the tour de France, the riders in the pack average about 250 watts with bursts of up to 1,000. For the average recreational rider, even 250 watts is unattainable. For example, top speed coasting downhill is about 25 mph. The pros in various time trials average over km/hr (31.7 mph). Because drag goes up as the cube of velocity, (32/25)^3=2.09, the rider is doing 210% of the work wih not even 1/3 more velocity. Looking at calories, an extreme workout on an elliptical trainer can burn 500 calories an hour. In contrast, a biker can easily do 1,000 caloriers/hr riding solo, on the flat, at 25 mph. Most bike trail riders do maybe 10-12 mph.

Becoming an engineer for a moment, the inefficiencies of electricity generation and storage make the proposition iffy at best. If you include the energy cost to create the proposed storage equipment, there is a huge net loss. So, enjoy your workout, and try not to worry about the losss of not too much work.

BTW, the photo is a fixed gear bike which is not for the faint of heart.

I test generators at work a 100kw 240VAC 3 Phase run at 100% for 3 hours I just hook it up to a load bank and turn it into a big electric heater. Now that is waste of energy.

A lot of expensive exercise bikes already use generators as the load. These machines aren't plugged in, and when you start pedaling, the whole thing just lights up. If it already has a generator of some kind, it wouldn't be too hard to charge a bank of car batteries, and run inverters off of those.

I'm a biker myself. When I exercise, I commonly burn twice the estimated calories, in half the time as the person next to me (and they think they are getting a workout!). The machine told me just a couple days ago that I burned 947 calories in an hour of biking, and that was only doing 140-160 watts (not sure how accurate those machines are, because that doesn't seem right). All that work could at least be doing something useful... I feel like I'm wasting my time and effort riding a stationary bike inside when it's cold out.

I could really easily power a fairly large lcd tv or a low power desktop (not my desktop... it uses like 250 watts all the time!), as long as it was around 100 watts. Put a scary movie on, and I would generate more power. That's how I did the 947 calories!

But if you had 10 people doing 100 watts (I'm pretty sure I could do 100 watts for hours at a time, so it's not that hard) you could get 1000 watts from them. You might be able to power the lights for that room, reducing power use. Another application could be for camping. Use something like this:
http://www.econvergence.net/electro.htm

and charge a battery with it. Then I could charge my electronics with an inverter. I've been wanting to do something like that... but haven't gotten to it.

-Nick