PDA

View Full Version : Sweatin' for the kilowatts



Shang
03-07-2013, 09:39 AM
Have you ever thought about connecting your hamster's exercize wheel to generate electrical power?

Gym Workouts Churn Out Energy for Colleges

" Two colleges are competing in a Kilowatt Throwdown to see which one converts the most kinetic energy from workouts into electrical energy. Tennessee Tech University and Chapman University started a month long competition on Feb. 15 to show their campus communities how small choices impact their world…Since September, 84,000 watt hours have been converted from kinetic energy through this project at Chapman, Crigger said. To put this number in perspective, that energy could power 12 homes for a year…"

http://www.centerdigitaled.com/news/Gym-Workouts-Kilowatt-Throwdown.html

Ian McColgin
03-07-2013, 09:53 AM
Yeah. There are what might be called "Green Gyms" where the equipment resistance is generators. Some of them cogen a considerable chunk of their energy. I gather it's not really cost-effective but it makes a great selling point.

Shang
03-07-2013, 11:00 AM
Remember Rowland Wilson's cartoon of the galley slave marching in chains toward the waiting trireme, saying: "What a magnificent ship! What makes it go?"

http://www.flickr.com/photos/dullhunk/7749083314/in/photostream/

Michael D. Storey
03-07-2013, 12:36 PM
power in is power out, less efficiency loses. I do not mean to dwell on the obvious, but why not take on the sun and the 'power in'?

BrianM
03-07-2013, 05:08 PM
A sad reality is that if you open up any piece of electrical excercise equipment, you will see an Automotive alternator. The core of these units is a solid state resistor or "Load" to which the alternator/generator is wired. All that sweat energy you put into the machine is simply converted to heat. Not one Watt of it goes into the grid, or even provides teh power needed to run the machine!! You will also note an electrical power cord connected to the wall to power the control panel and any cooling fan.....
It's even more maddening to have to replace a battery in the control unit/computer which preserves the memory in case you unplug the unit or keep it switched off too long.

Can we do better? Last time I looked, athletes can only generate 1/10hp or 754W/10... one modest incandescent lightbulb (75W), or a whole string of LEDs. It's far more efficient to have those people move cargo, or lift bales of hay if you want to convert efficiently, "Sweat into useful work".

Here's a good calculator for those interested in seeing what fraction of what you eat becomes available for mechanically translated energy.
http://www.aqua-calc.com/convert/power/horsepower-to-kilocalorie-per-hour

remember, one "calorie" in food-label terms is actually 1 kcal, but it is simplified for the general public who did not take (or remember) General Chemistry.