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The Power of a Hot Body

Posted by timothy on from the pickup-line-for-new-year's-eve-parties dept.

Hugh Pickens writes "Depending on the level of activity, the human body generates about 60 to 100 Watts of energy in the form of heat, about the same amount of heat given off by the average light bulb. Now Diane Ackerman writes in the NY Times that architects and builders are finding ways to capture this excess body heat on a scale large enough to warm homes and office buildings. At Stockholm's busy hub, Central Station, engineers harness the body heat issuing from 250,000 railway travelers to warm the 13-story Kungsbrohuset office building about 100 yards away. First, the station's ventilation system captures the commuters' body heat, which it uses to warm water in underground tanks. From there, the hot water is pumped to Kungsbrohuset's heating pipes, which ends up saving about 25 percent on energy bills. Kungsbrohuset's design has other sustainable elements as well. The windows are angled to let sunlight flood in, but not heat in the summer. Fiber optics relay daylight from the roof to stairwells and other non-window spaces that in conventional buildings would cost money to heat. Constructing the new heating system, including installing the necessary pumps and laying the underground pipes, only cost the firm about $30,000, says Karl Sundholm, a project manager at Jernhusen, a Stockholm real estate company, and one of the creators of the system. 'It pays for itself very quickly,' Sundholm adds. 'And for a large building expected to cost several hundred million kronor to build, that's not that much, especially since it will get 15% to 30% of its heat from the station.'"

21 of 161 comments (clear)

  1. Matrix by Andrewkov · · Score: 5, Interesting

    One step closer to The Matrix movie.

    1. Re:Matrix by calzones · · Score: 4, Insightful

      Not too far off considering that this concept is only worthwhile when bodies are generating excess heat that is unwanted in a space. But if you take away all the bodyheat being generated, then the people in that space will feel cold. To make up for it they will either dress warmer (insulate to keep their heat instead of sharing it) or they will expend more calories (which they must make up for by eating more) to generate more heat.

      So yes, kinda Matrix-like, this could easily turn into essentially draining a person's precious energy from them without their consent.

      --
      Asking people to think is like asking them to buy you a new car
    2. Re:Matrix by calzones · · Score: 2

      The problem is that if you pump the thermal energy out of the building where the "hot bodies" are without somehow knowing when to stop, there's nothing to keep the system from turning that comfortable space into something less comfortable and more like the winter temperature outside. That defeats the purpose because you're not going to save energy when that happens.

      At the extreme, it means the temperature in the space could become cold enough people want you to turn the heat on. A little less extreme and it means that people are less comfortable than normal and dress to avoid sharing their heat (making the space colder and making less heat available to the system).

      At the most subtle level, even a degree change of -1 degrees means that people will expend more personal energy to maintain their preferred body temperature. Conservation of energy demands that this personal energy come from _somewhere_.

      So, is it more carbon friendly to:
      - consume food and generate body heat?
        - or to heat a space by using traditional means that depend on centralized power generators?

      --
      Asking people to think is like asking them to buy you a new car
    3. Re:Matrix by aliquis · · Score: 2

      Or in this case accordingly to the article lower the temperature from 22-25 degrees celsius to something more comfortable (I don't know what that may be considering people will wear different kind of clothes different times of the year. Like atm people will use jackets and possibly mittens and a hat and hence 20 degrees may be too hot to feel comfortable and say 12-15 degrees more comfortable.

      In the summer people will dress more lightly but on the other hand there will be less demand for the heat.

    4. Re:Matrix by rhsanborn · · Score: 4, Insightful

      Spaces like train stations are usually over heated, so they generally need to be cooled. Instead of using the outside air as your heat sink, you are using a building across the street, who happens to want the heat. The train station becomes more comfortable, and a building gets heat without expending more carbon.

    5. Re:Matrix by Shinobi · · Score: 2

      The place they are taking the heat from is a place where people are dressed for winter during winter, so lowering the temperature is desireable in the winter too. The railway station mentioned, Stockholm Central, can get quite toasty if you're dressed for the outside weather, and there's lot of people inside....

  2. Headline by Anonymous Coward · · Score: 2, Informative

    Who else expected something completely different from the headline?

    1. Re:Headline by SternisheFan · · Score: 2

      I thought of strippers, naturally. Someday, I will get my mind out of the sewer, just not today.

    2. Re:Headline by hraponssi · · Score: 2

      Yeah, stories about the power of hot chicks over nerds. Damn, where is that article..

  3. How is this possible? by geckoFeet · · Score: 5, Funny

    The Swedes are such a cold people. Even the Danes consider them distant and formal (not to mention a bit condescending).

    1. Re:How is this possible? by KiloByte · · Score: 2

      It will have plenty of foreign visitors providing heat.

      I was there this August. I've seen plenty of hotties there, and from the looks, mostly locals rather than immigrants. Of course, during winter, when the heat is needed, all the hotness is covered by clothes.

      --
      The creatures outside looked from Alt-Right to Antifa; but already it was impossible to say which was which.
  4. Re:Power, not energy by ssam · · Score: 2

    do you mean "the human body generates about 60 to 100 Watts of energy" ?
    similar to saying
    "the car covers distance at 100 km/h"
    which is not too bad. i have seen much worse.

  5. 60W - 100W bulbs still commonly used? by metamarmoset · · Score: 3, Insightful
    The average light bulb around my area (W.Europe) is 9W - 11W.

    Maybe I'm nit-picking in finding this anachronistic, but this is a technology news site...

    1. Re:60W - 100W bulbs still commonly used? by dr2chase · · Score: 2

      Power cycling does NOT kill LEDs dead. Where do you get this information? LEDs are installed on bicycles running on one phase from a bicycle hub generator; at low speeds, it is flicker-flicker-flicker. Chopping LEDs at a kHz is a recommended way of modulating their power. LEDs are used for brake lights (and now, headlights) in modern cars; those are cycled frequently.

      The Phillips bulbs are notably NOT harsh; they're a low-color temperature light. I personally like a hotter (bluer) light, but that's not available yet in a good screw-in bulb (Home Depot has some other high-powered brand X that does a nice impersonation of a welding arc; THAT is harsh. Don't buy that one.)

      The neighbor post is an idiot. Modern high power white LEDs deliver a much more even spectrum than your standard fluorescent bulb. It's not black-body, but the LED I can buy at Home Depot is far better than any CFL or fluorescent tube I have ever bought anywhere (someone elsewhere asserts that very good fluorescents can be had, and I'm willing to believe it). If it's my own work -- mixed color temperature mounted under cabinets over a counter, I beat that handily. For example: http://dr2chase.wordpress.com/2011/02/20/undercabinet-lights-basement-kitchen/ Yes, there is a bit of a dropout at 480nm -- I know that was immediately obvious to you -- but if I cared, I would fill in with blue+cyan.

  6. Re:Power, not energy by necro81 · · Score: 2
    I agree. It irks me to no end when journalists, even science or engineering journalists, conflate (units of) energy and power. I guess I shouldn't be surprised, since hardly anyone else gets it right either. Nor, it seems, does anyone care. No wonder we can't have meaningful conversations about energy, where it comes from, and how we use it.

    Newly proposed wind farm to produce 100 megawatts of energy per month.

    MW are not units of energy. Megawatts per month makes no sense whatsoever.

    Or...

    Newly proposed wind farm to produce 100 megawatts of power per month.

    Power is already a time-rate unit, throwing the "month" in there just confuses things.

    Or...

    Newly proposed wind farm to produce enough energy for 30,000 homes.

    Over what time scale? Did they mean average power? What is the typical "home" journalists and PR folk use for this drivel? Homes consume power in different amounts - a highrise condo in NYC is very different than a McMansion in the 'burbs. The same house, occupied by different people, will use power at vastly different rates.

    Or...

    The human body generates more bioelectricity than a 120 V battery and over 25,000 BTUs of body heat

    Don't even get me started.

  7. Average bulb? Give me a break... by markdavis · · Score: 3, Insightful

    >" about the same amount of heat given off by the average light bulb"

    For the love of god, will people PLEASE come up with a better analogy than that tired, ancient one. I don't know about you, but I don't think I have more than one or two bulbs anywhere in my house that pull more than 20 watts, the average being more like 12.

    The "average light bulb" is hardly "average" anymore.

  8. Old hat. by kqc7011 · · Score: 2

    The Mall of America does a version of this.

    --
    Passionately Indifferent
  9. Re:The first thing I thought of was by kanweg · · Score: 5, Informative

    You can buy drainage pipes for the shower that are basically heat exchangers. Cold water is passed through them (in countercurrent with the water draining from the shower) before it goes to the shower head. Of course, you still have to add some hot water in the mixing faucet, but thermal energy is saved.

    Google: shower heat exchanger

    Bert

  10. Re:When I was in school, parties did this for $0 by Waffle+Iron · · Score: 2

    How many of you have been in a crowded house party in the dead of winter, with snow on the ground? Everybody piled their coats in a bedroom, the windows are open, and it's still hot. No money at all. If there are bodies in the room, and they're moving, it's hot.

    That heating method is very expensive due to the fuel costs.

    As soon as you run out of beer, you'll lose almost all of your heating elements. It will probably end up costing you a couple of hundred bucks per night to heat the house.

  11. Mall of America has been using body heat for years by MNNorske · · Score: 3, Informative

    The Mall of America was designed with the foreknowledge that people moving through it would generate heat. When I was working a volunteer event there a number of years ago the community relations contact we had was cheerfully explaining that they typically don't heat the mall. She cited a figure of 100 people generates about the same thermal output as an average household furnace. Which puts into context why a party in a house gets so warm... Most office towers in northern latitudes tend to heat primarily around the edges of the building where heat bleeds out of the tower through the windows. Otherwise you may find that the interior of the build could actually be receiving cool air to dissipate the body heat of the office workers.

    So, while I applaud the re-use of body heat for something useful, it's definitely not a new concept. Architects and engineers have been accounting for it and sometimes harnessing it for years.

  12. Re:Average bulb? Give me a break... by markdavis · · Score: 2

    >"Good for you, but the majority of people are still using incandescent bulbs."

    Not the people that I know. All my friends and family have higher than 50% non-incandescent, making non-incandescent the "norm" or "average". Most are much, much higher uptake than 50%. My last big jump from 60% to 95% happened last year when I was finally able to get LED BR30 tracklight bulbs (Utilitech Pro #0338929) that are:

    * Bright (650 Lumens)
    * True soft white (2700K)
    * Flood, not spot
    * Fully dimmable
    * X10 compatible
    * Instant 100% full brightness
    * Affordable

    I thought it would be Philips that could do it first, but these no-names (from Lowe's, I think it was) have impressed the hell out of me. Florescent BR30 bulbs were never the right color, noisy as hell, completely X10 incompatible, take a while to brighten, and really never last as long as claimed.