Gym creates its own electricity from exercise bikes.

Page 2 - Seeking answers? Join the AnandTech community: where nearly half-a-million members share solutions and discuss the latest tech.

BoomerD

No Lifer
Feb 26, 2006
63,130
11,501
136
Hmmm....the energy companies seem to all be Republican in nature...so I think joesmoke is slightly off base...:p

Now, of a far greater concern...do they pay their customers for the electricity generated? I'll be dammed if I'll pay them for the "privilege" of making electricity for someone else...
 

Zebo

Elite Member
Jul 29, 2001
39,398
19
81
That one of those deals like why didn't I think of it. So simple and effective...every gym should have been creating it's own power for years since generators and batteries are 100 years old.
 

ElFenix

Elite Member
Super Moderator
Mar 20, 2000
102,418
8,370
126
the exercise bikes at my gym seem to be self powered. the treadmills are not.
 

Zebo

Elite Member
Jul 29, 2001
39,398
19
81
$50 cost.

Let's say it has about 50% efficiency, and that electricity costs $0.13 per kw-hr. Not too difficult to have someone run up a few flights of stairs, time them, and get a rough approximation of their power output. I've seen several bigger guys achieve slightly more than 1kw, but only for very short durations. According to some chart I found googling, if I average 20mph on a bike (which I used to easily be able to maintain for well over 20 miles on relatively level, smooth roads), I burn 38 calories per mile. That's 760 calories in an hour. I assume they mean kilocalories, as in food calories. That converts to 3179840 joules per hour. Or, dividing by 3600, errr, uhhh, that's 883 watts, which clearly shows that nutritionists are full of shit when they talk about how many calories you burn while exercising. So, let's say it's 400 watts. And, you're able to convert even 1/3 of them to electricity. 133 watts. That's 7.5 hours of biking to produce one kilowatt-hour.

So, you'd have to ride a bike a little shy of 3000 hours before you broke even on the $50 investment. If you go by the user's experience above where it was difficult to keep a 100 watt lightbulb lit - I'm assuming someone in average shape, you're looking at closer to 4000 hours to break even.3 179 840 joules

Umm how much you think those baldor motors cost inside treadmills and ellipticals? I just replaced one in home landice and was over $500. Replace them with generators instead, whom offer resistance and generate money you are far ahead.
 

Train

Lifer
Jun 22, 2000
13,862
68
91
www.bing.com
Umm how much you think those baldor motors cost inside treadmills and ellipticals? I just replaced one in home landice and was over $500. Replace them with generators instead, whom offer resistance and generate money you are far ahead.

Ya that's what I was thinking, if these bikes were manufactured from the start to be generators, they probably wouldnt cost much more than they already do. Then you get the added benifit of decreasing the amount of electricity you have to pay for.
 

GoSharks

Diamond Member
Nov 29, 1999
3,057
0
76
You guys are still greatly overestimating the amount of power that can be generated.
 

ConstipatedVigilante

Diamond Member
Feb 22, 2006
7,671
1
0
Could one harness the power from weight-lifting machines somehow? There's a lot of work that goes into each rep on the higher weight levels; I imagine a gym full of muscle heads would be able to generate more power than a bunch of girls on exercise bikes.
 

gorcorps

aka Brandon
Jul 18, 2004
30,739
451
126
Now just think... If we combined those magnetic induction flash lights with a fleshlight and gave them to AT, our energy problems would be solved.
 

nonameo

Diamond Member
Mar 13, 2006
5,949
3
76
The sad thing is, the harder you work out at the gym, the more food you will eat. This will offset any cost savings from energy generated and will screw up your "carbon footprint"(what BS) too.
 

Eli

Super Moderator | Elite Member
Oct 9, 1999
50,422
8
81
See my links. The first one is directly from a power meter attached to the guy's bike.

That's freakin' sweet. And incredible. :eek: I cannot imagine being able to burn almost 1,000 calories an hour for hours on end. Holy shit.

DrPizza's estimate is surprisingly accurate.. Assuming that a normal person would not be able to come anywhere near 225+ watts for 100+ miles.. lol.

I bet 133 watts for ~20mi would be possible for someone in decent shape though.
 
Last edited:

Eli

Super Moderator | Elite Member
Oct 9, 1999
50,422
8
81
The sad thing is, the harder you work out at the gym, the more food you will eat. This will offset any cost savings from energy generated and will screw up your "carbon footprint"(what BS) too.

Shrug. Though I understand what you mean, and agree in principle, it is still a positive attitude and thought. The problem is that the movement is still in it's infancy. If/when everyone in every industry decides to "lower their carbon footprint", or you chose to only deal with companies that have done so, you would be contributing.
 

DrPizza

Administrator Elite Member Goat Whisperer
Mar 5, 2001
49,606
166
111
www.slatebrookfarm.com
Could one harness the power from weight-lifting machines somehow? There's a lot of work that goes into each rep on the higher weight levels; I imagine a gym full of muscle heads would be able to generate more power than a bunch of girls on exercise bikes.

The exercise bike has a far higher power output. I frequently have students calculate their power output by running up a few flights of stairs. Many of them think beforehand that the fastest kids are going to have the highest power output. Wrong. It's usually the heaviest kids (who are in at least average shape.) Reason: bigger muscles are capable of more power output. And, leg muscles are bigger than arm muscles.
 

DrPizza

Administrator Elite Member Goat Whisperer
Mar 5, 2001
49,606
166
111
www.slatebrookfarm.com
Also, one of the links above about the university in Texas:
According to the company's website, a 30-minute workout produces 50 watt hours of electricity, though Bennion said that estimate was "very rough." That amount of energy could power a fluorescent light bulb for about three hours or a laptop for about one hour, according to the U.S. Department of Energy.
A bit of failure there. Let's assume they meant they maintain an average of 50 watts of power output. (for the 30 minutes). That amount of energy produced would be equivalent to 25 watts running for a full hour. A laptop only uses 25 watts? And I just bought a dozen CFL's. 14 watts each, so it falls short of 3 of them.

Note: people selling energy savings tend to round up on one end & round down on the other.

Another edit: Eli suggested that an "average" person couldn't maintain 225 watts for an extended amount of time. To put that in perspective, That's 225 joules per second. An 75 kilogram person (165 pounds) would need to climb roughly 1 foot per second for that output. (11.8")
 
Last edited:

Eli

Super Moderator | Elite Member
Oct 9, 1999
50,422
8
81
Also, one of the links above about the university in Texas:
A bit of failure there. Let's assume they meant they maintain an average of 50 watts of power output. (for the 30 minutes). That amount of energy produced would be equivalent to 25 watts running for a full hour. A laptop only uses 25 watts? And I just bought a dozen CFL's. 14 watts each, so it falls short of 3 of them.

Note: people selling energy savings tend to round up on one end & round down on the other.

I can get my laptop down to 17.2W actual, 19W after power brick losses(Kill-A-Watt reading).

That's with the LCD all the way dim and some pretty aggressive clock throttling. But yeah, 25W sounds about average, perhaps a bit low for a laptop.

A netbook on the other hand.. I have no idea how much power they use, too lazy to look it up, but it must be well under 10 watts. They are small(and therefor have small batteries), and can last for like 10 hours.

When/if we go off grid, they will probably be the computer of choice.

(Hmm.. can you be considered "off grid" if you have a satellite connection to the world?)
 

jiggahertz

Golden Member
Apr 7, 2005
1,532
0
76

disappoint

Lifer
Dec 7, 2009
10,137
382
126
Also, one of the links above about the university in Texas:

According to the company's website, a 30-minute workout produces 50 watt hours of electricity, though Bennion said that estimate was "very rough." That amount of energy could power a fluorescent light bulb for about three hours or a laptop for about one hour, according to the U.S. Department of Energy.
A bit of failure there. Let's assume they meant they maintain an average of 50 watts of power output. (for the 30 minutes). That amount of energy produced would be equivalent to 25 watts running for a full hour. A laptop only uses 25 watts? And I just bought a dozen CFL's. 14 watts each, so it falls short of 3 of them.


A bit of reading comprehension fail there? They said 50 watt hours not 50 watts.
 

Cogman

Lifer
Sep 19, 2000
10,277
125
106
If they really wanted to save the world they could replace all of their light bulbs with LED lights. Not only that, they should skip the "Convert to AC" phase of their power scheme. Plenty of lights will run on DC only power (which is what their gym should be running on).

Charge a couple of batteries, light the facilities with the energy stored in the batteries. Trying to put it back into the grid is fail.
 

Zebo

Elite Member
Jul 29, 2001
39,398
19
81
How do you turn calories into watts? My HRM says I burn over 800 calories when running. Assuming you could harness that in a treadmill instead of wasting it on the street I bet I could power the lights at least.
 

silverpig

Lifer
Jul 29, 2001
27,709
11
81
How do you turn calories into watts? My HRM says I burn over 800 calories when running. Assuming you could harness that in a treadmill instead of wasting it on the street I bet I could power the lights at least.

google

"800 kilocalories / 1 hour in watts"

gives

(800 kilocalories) / (1 hour) = 929.777778 watts