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Power Science

Using Gym Rats' Body Power to Generate Electricity 338

Posted by CowboyNeal
from the other-biodiesel-generators dept.
Carl Bialik from WSJ writes "A Hong Kong health club is hoping that a car battery, some StairMasters and dozens of gym rats can help ease the world's energy problems. It is just one of a wave of projects that are trying to tap the power of the human body, the Wall Street Journal reports. The article explains the impetus behind the project: 'The human power project at California Fitness was set in motion by Doug Woodring, a 41-year-old extreme-sports fanatic and renewable-energy entrepreneur, who pitched the experiment to the gym's management last May. "I've trained my whole life, and many megawatts have been wasted," says Mr. Woodring, who has worked out at the Hong Kong gym for years. "I wanted to do something with all that sweat."'"
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Using Gym Rats' Body Power to Generate Electricity

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  • by Reverse Gear (891207) * on Friday March 02, 2007 @06:31AM (#18205040) Homepage
    The article doesn't hide this either, but there is really very little real energy to be won in this way, I don't really get what Mr. Woodring says about megawatts being wasted though, no human is able to generate that much electrical power, maybe he refers to megawatthours which he might be right about, but it would have been generated over the span of many years.

    I think it would be more efficient if the people who go to the gym instead would just put on a pair of running shoes and would not have to exercise in a room that had not to be lit and heated for the purpose of them having a place to exercise.

    I guess the best thing about this is that it might raise some people's awareness of how much energy different electrical devices use during the day and might help them remember to shut them off and think of energy efficiency when they buy new equipment.

    The good thing about the way the human body works is not how much energy we use or generate, our biggest strength in this is the precise and versatile we can use our bodies and the energy we generate from the our food intake.
    For example I bet you can save a lot more energy and pollution from exercising by getting wood for heating than you would ever be able to make by exercising a stair machine or spinning device.
  • More like (Score:5, Insightful)

    by Zouden (232738) on Friday March 02, 2007 @06:32AM (#18205042)
    It is just one of a wave of projects that are trying to tap the power of the human body

    I'd say it's just one of a wave of projects that are trying to tap the venture capital being thrown at "environmental-yet-supposedly-profitable" schemes.
  • by Baron Eekman (713784) on Friday March 02, 2007 @06:45AM (#18205092)

    Indeed. If you want power, just burn the food you eat, that can be done far more efficiently.

    And guess what your body produces by generating power from sugar: yes, carbon dioxide. There is no environmental gain here at all.

  • by Anonymous Coward on Friday March 02, 2007 @07:11AM (#18205196)
    Why are americans so ignorant and uneducated when it comes to CO2. It is as if you dont learn this stuff in compulsory highschool. What is it americans actually DO in high school? Bible studies or some shit like that? :)

    When our bodies burn sugar we exhaust CO2, yes. But since this CO2 was originally taken from the air during the growth of the plant, there is no net addition of CO2 to the atmosphere. The food we eat is grown in our atmosphere; thus we have a CO2-circle. If this natural CO2-circle somehow was unstable and more CO2 was released than what was consumed we would not be living today. Think before you write.

    This would be an environmetal benefit if we compare to generating the same energy by burning fossil fuel. Say coal. Burning coal is not part of the CO2 cycle - thus it adds CO2 to the atmosphere. The danger is NOT CO2; but from where the C in CO2 come frome. Why do you always get this wrong, its quite irritating.

    Also I guessed the first reply to this post would correct you, but noo.
  • by Eivind (15695) <eivindorama@gmail.com> on Friday March 02, 2007 @07:19AM (#18205240) Homepage
    Possibly, but doubtful. As stated, if the exersize-bikes where in use for 10 hours/day, they'd pay back the investment in 82 years, but since they probably get replaced within 5 years anyway, that's never going to happen.

    It's much easier to *save* energy than to *create* it.

    Replacing 10 of the ligth-bulbs in the gym with modern low-energy ones would've had a larger effect on energy-savings, and would've costed less than the $15.000 this cost.

    It's a gimmick, nothing more.

  • by MightyYar (622222) on Friday March 02, 2007 @07:19AM (#18205246)
    A lot of petroleum is used in the food production chain, so you aren't quite carbon-neutral unless a bio-fuel is being used with all of the farm equipment, food processing equipment, and transportation infrastructure which brings the food by train or truck to your store.
  • Re:How about (Score:3, Insightful)

    by MightyYar (622222) on Friday March 02, 2007 @07:24AM (#18205266)
    Have you ever used those lights on the bike which use a little generator that goes down on the wheel?

    In my experience, quite a bit of resistance is added to my peddling, and that's just to light up a puny bike headlight!
  • by LarsWestergren (9033) on Friday March 02, 2007 @07:35AM (#18205318) Homepage Journal
    maybe he refers to megawatthours which he might be right about, but it would have been generated over the span of many years.

    For one person yes, but if you have hundred or thousands of customers per day pedalling/rowing/stairstepping, it adds upp quickly

    I think it would be more efficient if the people who go to the gym instead would just put on a pair of running shoes and would not have to exercise in a room that had not to be lit and heated for the purpose of them having a place to exercise.

    a) People in big cities rarely have good places outdoors to run. b) If it is winter and snowy, it can be difficult to excercise outside too. c) Some people prefer to build muscles over doing cardiovascular excercise. d) Heating and lighting a gym isn't more wasteful than heating and lightning any other room.

    I guess the best thing about this is that it might raise some people's awareness of how much energy different electrical devices use during the day and might help them remember to shut them off and think of energy efficiency when they buy new equipment. The good thing about the way the human body works is not how much energy we use or generate, our biggest strength in this is the precise and versatile we can use our bodies and the energy we generate from the our food intake. For example I bet you can save a lot more energy and pollution from exercising by getting wood for heating than you would ever be able to make by exercising a stair machine or spinning device.

    Now these points I agree with 100%. :)
  • by Tim C (15259) on Friday March 02, 2007 @08:07AM (#18205476)
    I think it would be more efficient if the people who go to the gym instead would just put on a pair of running shoes and would not have to exercise in a room that had not to be lit and heated for the purpose of them having a place to exercise.

    While that's true, running isn't ever going to replace gyms. Two immediate reasons are that running does little or nothing for building up muscle bulk, and it's a high impact exercise (as opposed to something like swimming or cycling, where you're not pounding the pavement the whole time).
  • by MrNaz (730548) on Friday March 02, 2007 @08:15AM (#18205530) Homepage
    Remind me again why you treadmill people don't just go outside?
  • by Aladrin (926209) on Friday March 02, 2007 @08:18AM (#18205544)
    Maybe it's about efficiency. If they spare time, they might choose to do just that. For the rest of us (who have NO spare time) it's about getting the most efficient exercise in the time we have.
  • by Eivind (15695) <eivindorama@gmail.com> on Friday March 02, 2007 @08:28AM (#18205592) Homepage
    True. Nevertheless, for this application, even an order of magnitude reduction in price wouldn't be enough. Currently it takes 82 years for payback -- assuming 10 hour/day usage (which is excessive, very few machines are in practice used even half of this)

    So, with an order of magnitude improvement, (i.e. $1500 not $15.000) in price, you'd still be looking at 8.2 years of 10 hour days for payback. (or on the order of 20 years or more for more typical gym-use) this for equipment that is typically replaced after aproximately 3-5 years.

    Harvesting "human power" will never be able to do much for your energy-bills. It can make sense for other reasons though. For example, a handy that is powered by movement, and thus stays charged forever aslong as you're walking/moving would be a very practical thing to have for many people. I'd love this in my GPS too: I only bring it along when I go hiking in the mountains anyway, if my movements could somehow supply the (small; sub 1w) power-requirements it'd mean I could have it on all the time and never worry about running out of batteries again, rather than turning it on to log a certain point-of-interest only occasionally during the hike as I do today.

    With low-enough energy-demands I could see this for for example remote-controls or wireless game-controllers too. Never having to replace batteries is a nice thing, more for practical reasons than for cost-reasons. (rechargable batteries aren't that expensive anyway)

    Infantry also has need for gadgets. Many of them would benefit from being able to work indefinitely without access to recharging and/or new batteries. (nigth-vision, GPS, radio, led-torches, ...)

  • by Anonymous Coward on Friday March 02, 2007 @09:55AM (#18206066)
    He'd better keep his day job at the gym or crack a few books on electical engineering and thermo before he shoots his mouth off again to potential investors. What a dope.

    This reminds me of all the waiters in LA who claim to be actors. But this would be more like waiters claiming to be Physicists, waiting to be discovered....

  • by squoozer (730327) on Friday March 02, 2007 @10:54AM (#18206572)

    While I agree with what you are saying I wish people wouldn't prefix "chemicals" with "nasty". It shows a fundamental lack of understanding of chemistry and is anthropomorphizing a non-living thing.

    The plastic that the battery is surround in is a chemical, the clothes you where are made of chemicals, the food you eat is chemicals. There are no "nasty" chemicals. There are certainly chemicals that are dangerous to us and there are chemicals that are difficult to dispose of and plenty of other classifications. If this is a lead acid battery (which I'm guessing it is) then the acid, the thing most people would point at and say that's a chemical, is probably one of the least harmful components. The feed stocks for the plastic that made the battery casing are often horribly toxic as are some of the plasticizers that are used. Metal production produces huge quantities of waste material and consumes vast amounts of power.

    I suppose the other components don't count as chemicals though as they aren't liquids and under standard conditions they don't really do much.

  • by Afecks (899057) on Friday March 02, 2007 @12:57PM (#18208032)
    Fat people get it the worst. No other group of people are so easily attacked and mocked. Most people wouldn't dare say "look how black that guy is!" for fear of being labeled a racist. However, very few of the same people would have any problem saying "look how fat that guy is!". Calling someone a nigger, faggot or fatass are all in the same group of insults. They are insults designed to hurt someone by mocking their differences. Yet somehow we all let that last one just slide by.

    We accept each others differences when it comes to race, religion, sexuality but since being fat is "unhealthy" then it's unacceptable. I call bullshit on that. There are no special exceptions when it comes to bigotry.

    But I'm not telling anyone what to do, just making an observation.
  • by necro81 (917438) on Friday March 02, 2007 @01:13PM (#18208222) Journal
    The article describes the system as siphoning off excess power from the generators already built into the equipment to run the exercise computers. It is like the dynamo on a bicycle - a parasitic power sink. They are only capturing a small fraction of the available power. The majority of the power the human inputs into the gym equipment still goes into waste heat production, same as the unmodified equipment.

    A much better way to capture human power would be to scrap the power sink (the friction mechanism, for instance) and replace it with a real electrical generator, not just some dynamo rated for a couple of watts. With the proper power electronics, you can adjust the mechanical resistance that the human feels by adjusting the electrical power drawn from the generator. This would be similar to how regenerative braking works in hybrid cars. The braking action can be soft or hard, depending on the pedal input, and works by modulating the power drawn out of the generator and into the battery bank. Like a hybrid car, the mechanical resistance (i.e., traditional brakes) becomes almost superfluous.

    This system would allow you to capture far more of the human power and convert it to electricity. With a well-chosen generator and well-designed power electronics, the conversion efficiency can be over 75%. For a human producting 100 W on a stationary bike (a decent workout), that would be 75 W of electricity.

    This idea does, however, require a more substantial redesign or retrofit of the existing equipment, designed into the equipment and the gym from the beginning. As a result, I think it is unlikely to come about anytime soon. It would be a fun home project, however. Anyone know if Make Magazine has done something with this?
  • by Suidae (162977) on Friday March 02, 2007 @01:45PM (#18208652)
    I ran the numbers recently as well, here is what I came up with. Note that I didn't do any actual measurements and relied only on what I could find in google with a few minutes searching. I've made some pretty generous (read, unrealistically optimistic) assumptions about what the human body is capable of and what people will put up with to have power.

    Here is a ballpark estimation of the practicality of human power generation.

    Let's assume that a person who's profession was power generation would be highly fit and well suited to long hours turning a generator at high output. If such a person could maintain an electrical output of 400W for 10 hours a day he would produce 4 kilowatt hours of electrical energy (ignoring conversion loss for the sake of simplicity). This is beyond mere 'Olympic' performance and well into the realm of the 'heroic', similar to a good bicycle sprint for 10 hours.

    Given a heroic muscular efficiency of 30% (beyond the human normal range of 14-27%) this 4 kilowatt hours represents about 13kWh of input power, or food. This is about 11,000 dietary calories. I'll presume that the waste heat is too low-grade for power generation, but could be used to offset living space heating requirements during cold weather.

    If we feed our hero nothing but soybeans (inexpensive and fairly energy dense at 1.75cal/gram and 0.00025 cents per gram in bulk ($6.80 for 60lb) he will need about 6.25 kilos of beans a day, at a price of about $1.60.

    So your human power will cost in the range of 40 cents per kilowatt hour, or about 4 times the price of grid electrical power, presuming you can find teams of heroes willing to donate their time for free.

    The US consumes around 4,000,000,000,000 kilowatt hours per year. At a rate of 1460 kWh per hero per year, you will need to employ 2,700,000,000 people (almost half the world population) each year to produce the required electrical power. Feeding them will require about 6,100,000,000,000 kilos of beans a year, or about 90 times the annual US soybean crop. You may be able to reduce the number of people required slightly with a methane capture system :) You can probably increase efficiency by feeding the heros that die in the line of duty to the living heros, thereby recyling a hundred or 2 pounds of material.

    A typical household in the US consumes about 30 kWh per day. Consider that this is about 8 heroes pedaling generators in your basement, consuming a 40 pound bag of soybeans each day.

    Powering a typical smallish refrigerator requires about one kilowatt-hour per day, so it would only take one hero two and a half hours to keep your food cold (or, if he is charging a battery, 5 hours after losses).

    A typical real person could reasonably be expected to produce 200W for an hour a day (maybe 2 for extremely dedicated individuals), certainly enough to charge small devices like laptops, but just a drop in the bucket next to the power used by a typical person.

    Kinda puts the power of fossil fuels into perspective.

    refs:
    http://www.eia.doe.gov/emeu/reps/enduse/er01_us.ht ml [doe.gov]
    http://www.los-gatos.ca.us/davidbu/pedgen.html [los-gatos.ca.us]
    http://globalis.gvu.unu.edu/indicator_detail.cfm?I ndicatorID=46&Country=US [unu.edu]
    http://www.whfoods.com/genpage.php?tname=foodspice &dbid=79 [whfoods.com]
    http://www.sciencedaily.com/releases/2006/03/06032 2113511.htm [sciencedaily.com]
    http://coachesinfo.com/category/rowing/77/ [coachesinfo.com]
    http://homepage.mac.com/moises.santillan/paper [mac.com]
  • by Anonymous Coward on Friday March 02, 2007 @05:00PM (#18211498)
    Obesity is no more a social "difference" than being a pot/cigarette smoker or a high-school dropout. It's irresponsible behavior, not a social difference. Should we ban all of the anti-drug commercials because they may hurt some pot head's feelings?

    Calling fat jokes "bigotry", and comparatively trivializing *real* bigotry, is an insult to the plight of those who actually face it.

    Minority groups were marginalized, tortured and lynched at various points in history. You get asked where the nearest Burger King is. Go eat a twinky, tub-o.
  • by Migraineman (632203) on Friday March 02, 2007 @05:33PM (#18211980)

    My brother-in-law is tipping the scales at 450+ lbs. He goes out of his way to make eating easier. He stores food on the couch ... days-worth of food, not just a bag of chips. He goes out of his way to eat poorly - fast-food and junk-food are at the top of his list. He was recently hospitalized due to a combination of sleep apnea, narcolepsy, and pneumonia - all related to his obesity.

    He's not a bad guy, but he does have psychological issues. His obesity is completely elective - when he was dating several years ago, he got down to about 250 lbs. If he wishes to flush his life down the toilet, that's his preroggative. However, the moment it affects me, it becomes my problem. When he visits, we have to make all sorts of special accommodations for him. I don't recall ever making special accommodations for someone based on their religion, their skin color, their hair color, their sexual preference, etc. My next door neighbor has been in a wheelchair as long as I've known him, and he requires less "special attention" than my brother-in-law.

    And the part that makes me furious, is that he's unwilling to accept responsibility for his situation. The denial and littany of excuses are monumental - it's glandular, it's an endocrine imbalance, it's a disease. Disease? How the hell do you "catch" obesity from someone else?

    Here, I'll solve the problem with physics: (1) Eat less, you'll lose weight. Your body can't manufacture fat out of the aether. (2) Sell the TV. Now that you've freed up some time, go for a walk.
  • by ZDRuX (1010435) * on Friday March 02, 2007 @06:57PM (#18213054)
    No, that is not true.. You *CAN* deal with obesity and overweight problems and "beauty" problems, but you CANNOT deal with or *cure* your skin colour, or if you're missing a leg, or you have problems breathing, this is the main difference why I find it "easier" to laugh at people who are dirty, smelly, fat, lazy, or stupid - because all those can be taken care of, whereas anything you're born with, or physically stuck with is not. This is why it's NOT OK to laugh at handicapped people or people with mental retardation or anything of that kind.

"Love may fail, but courtesy will previal." -- A Kurt Vonnegut fan

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