electricity from a gym: quick calcs

[me]

[email protected] wrote in

Maybe he's a Tour de France rider?

I also didn't specify whether my 100W was power input or power
output. If it's power output, the rider will have to ride harder due
to inefficiencies in the power conversion, of course... 200W? what's
a typical small generator efficiency? 50%? 90%?

Michael

The whole thing is so obviously stupid I'm surpriesed this thread has
lived this long...

 

[Rene Tschaggelar]

Accordding to this link, 75 watts is sustainable on average:
http://www.humboldt.edu/~ccat/pedalpower/hec/hpeg/index.html

Where did you get yoyr 300 watt figure?

At the local enginering school, friends built a bike for
just this purpose. Driving a DC machine to illuminate
lamps. Every 50W, another lamp was added. That was 25
years ago. As I believe to remember 300W was just doable
for few minutes. We weren't bikers then, but are now.
So I'd assume these 300W to be doable for some while. Oh,
we're biking in the hills, not in the flat.

Rene

 

[ehsjr]

At the local enginering school, friends built a bike for
just this purpose. Driving a DC machine to illuminate
lamps. Every 50W, another lamp was added. That was 25
years ago. As I believe to remember 300W was just doable
for few minutes. We weren't bikers then, but are now.
So I'd assume these 300W to be doable for some while. Oh,
we're biking in the hills, not in the flat.

Rene

Thanks. That seems reasonable for well conditioned cyclists.

Ed

 

[[email protected]]

[email protected] wrote in






The whole thing is so obviously stupid I'm surpriesed this thread has
lived this long...

Then why bother posting, if you have no useful information? Maybe you
belong in the "I Just Plonked Eeyore" thread?

 

[Joel Kolstad]

Thanks. That seems reasonable for well conditioned cyclists.

There are some interesting numbers at:
http://en.wikipedia.org/wiki/Human-powered_transport -- perhaps the salient
one here being that well-conditioned cyclists can produce ~200W for over an
hour, with short bursts burst 1500-2000W.

Human-powered aircraft require a continuous ~200-250W input -- that guy who
crossed the English Channel wasn't just a weekend rider.

Interestingly, an ultra-lightweight single-man aircraft covered with solar
panels can generate a couple kilowatts when the sun is shining brightly.

 

[Rich Grise]

Thanks. That seems reasonable for well conditioned cyclists.

When I was in high school, the physics class did an experiment.
There was a two- or three-flight staircase, and guys would
volunteer to run from the bottom of the stairs to the top, timed.

Now, this wasn't restricted to legs - we were allowed to grab
the railings, vault, whatever we needed to do to get to the
top of that staicase as fast as humanly (teenagerly?) possible.
Then, the calcs were quite simple; the guy raises X pounds Y feet
in Z seconds. Some of the more athletic gus achieved almost a
horsepower (746 watts), for about six seconds.

Cheers!
Rich

 

[[email protected]]

according to the bike at the university gym, when I started exercising
a year ago, I produced 67 watts CW, not I'm not such a fat ass anymore
and go cycling every weekend, I do about 90 CW, 140 peak for say 30
seconds. I'm 37, younger punks could do more.

there, some real numbers

Steve Roberts

 

[Jim Thompson]

according to the bike at the university gym, when I started exercising
a year ago, I produced 67 watts CW, not I'm not such a fat ass anymore
and go cycling every weekend, I do about 90 CW, 140 peak for say 30
seconds. I'm 37, younger punks could do more.

there, some real numbers

Steve Roberts

I'm 67, and produce 45 watts with my arms. Don't know about legs...
after the hip joint replacement next month I'll see.

...Jim Thompson

 

[Guest]

I had a conversation with a co-worker about harnessing energy from
folks dancing on a dance club, and from folks walking in a mall during
the shopping season. I was skeptical, thinking the capital costs
would outweigh any benefit, but decided to run the calcs just to be
fair.

If you could come up with a cheap do-it-yourself liposuction
machine, the fat could be burned as fuel...