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Earth Technology

The Power of a Hot Body 161

Posted by timothy 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.'"
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The Power of a Hot Body More

The Power of a Hot Body

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  • Matrix (Score:5, Interesting)

    by Andrewkov ( 140579 ) on Monday December 31, 2012 @09:11AM (#42431955)

    One step closer to The Matrix movie.

    • Re:Matrix (Score:4, Insightful)

      by calzones ( 890942 ) on Monday December 31, 2012 @09:50AM (#42432103)

      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.

      • Re: (Score:1)

        by Anonymous Coward

        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 it is a self-regulating system, great.

        In the current state people generate excess heat so they need cooling. Transporting the excess to a place where people doesn't generate enough heat is not exactly a sign of a dystopian future.

        • 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 i

          • Re:Matrix (Score:5, Insightful)

            by rhsanborn ( 773855 ) on Monday December 31, 2012 @10:44AM (#42432383)
            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.

            • Yes, I said that up front.
              As long as you are doing this to avoid having to cool a space that you'd have to otherwise cool, then yes, it's a net win.

            • Re: (Score:2)

              by jhol13 ( 1087781 )

              Except when they are not - in the mornings. I eat every working day in a restaurant which is uncomfortably cold if the (outside) temperature has dropped during night or worse, weekend.

              This idea has some uses, but is very limited what it can achieve. Bad planning can make it more a nuisance than an energy saving.

          • Re: (Score:3)

            by Shinobi ( 19308 )

            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....

          • Re: (Score:1)

            by Anonymous Coward

            You clearly live somewhere that doesn't have many large train stations. When it's cold outside, you don't have to heat a train station. It's close to sweltering hot and wet inside just from all the people. The solution to this is to ventilate the area with outside air. In doing this you are losing all that heat to the outside. This plan is to capture that lost heat and use it to heat a different building.

            I used to live in Russia, and you have to wear lots and lots of layers in the winter. When you get

          • A) A simple thermostat to shut off the system if the ambient temp drops below a threshold value isn't that difficult
            B)Efficiency drops as the temp of both areas approach one another, so its not like you can forcibly drain one location to keep the other super hot.
            C)This isn't a system to use in Kenya. Most people in modern countries already consume more calories than they need, so the argument that they would need to eat is invalid. It could even be marketed as a weightloss aid if it had a marked increase in

      • Re: (Score:2)

        by aliquis ( 678370 )

        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.

      • Re: (Score:2)

        by devent ( 1627873 )

        I think any closed room with more then 10 people needs to have a ventilation system. Either you throw away that heat or you using it.

        It's a shame that we don't have more buildings like that, that can use heat from the sun or people for anything useful. Termites nest have a strict regulated temperature (like 1 degree Celsius strict) without any ventilation or air-conditioners.

        My apartment is on the north side of the house block. With mirrors and fiber optics I could get the same sun then my neighbour. I was

      • That radiated heat was going to be lost into the atmosphere, and probably from thence eventually into space. Capturing heat from air that was already being vented would have no effect on the temperature of the rail car.

        • I don't think this has anything to do with Chernobyl. The heat carried away from the passenger's bodies is carried off by convection. The passengers aren't really glow-in-the-dark radiaoactive.

          • Just so you know, everyone gives off "light" in the infrared spectrum, and radiated heat (infrared) is one of the main ways that heat is lost both from our bodies and from the earth. Convection is another way, but you will note for instance that the earth loses enormous amounts of heat despite convection losses against the vacuum of space being minimal.

            • You also lose quite a lot of heat when you breathe.

              The bodyheat that is "lost" to the building is also trapped by the building walls and ceiling; it doesn't radiate into space very effectively. In fact, it's a part of our global warming problem that we give off so much heat into the atmosphere from our buildings and vehicles... faster than the heat can be radiated into space.

              As long as the walls and ceiling remain a certain temperature, then the ambient temperature will remain stable. If the walls are cool

      • So... you're saying that when noone captures your bodyheat, you don't generate any? I really really don't see the logic here. Why on earth are you assuming that people don't lose bodyheat? Why the word 'drain'? Its not a heatdrain, its using excess heat and transfering to another building. damn you slashdot for modding this shoddy logic 'insightful'

      • Re: (Score:2)

        by mikael ( 484 )

        Have you ever been in a underground station (or even glassy college campus corridors in Summer) where there are hundreds of people walking through. The humidity and heat does build up, even when they are wearing winter jackets and shoes. Places which do suck out all the heat just feel ice cold, and will be avoided when possible.

      • Re: (Score:2)

        by tlhIngan ( 30335 )

        Not too far off considering that this concept is only worthwhile when bodies are generating excess heat that is unwanted in a space.

        Not really a new concept - the Mall of American actually has no heating system - no boilers or other heating mechanism. It does have chillers and A/C (and sometimes it runs in the middle of winter).

        It uses body heat (of the shoppers) and solar heating (sunroofs) to keep the entire place warm (70F) in those chilly 10F Minnesotan winters.

        Certain offices are also dense enough that

    • Re: (Score:1)

      by Anonymous Coward

      The Power of a Hot Body

      One step closer to The Matrix movie.

      you surely mean Carrie-Anne Moss (the hot body)

  • Headline (Score:2, Informative)

    by Anonymous Coward

    Who else expected something completely different from the headline?

  • Comment removed based on user account deletion
    • Which is why they aren't pumping the air directly, but instead, they are using the body heat to heat water tanks, and sending the water across.

  • How is this possible? (Score:5, Funny)

    by geckoFeet ( 139137 ) <gecko@dustyfeet.com> on Monday December 31, 2012 @09:24AM (#42432001)

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

    • And we consider the Danes a bunch of fat, loud-mouthed alcoholics. No wonder you consider us cold.

      • "You?" I'm not Scandinavian at all (short and dark, in fact). Did spend a winter in Stockholm, and definitely wouldn't recommend it for the weather. Also have to add, in case it's not obvious from your message, that the Danes have a much better sense of humor than the Swedes, and better beer as well.

    • Re: (Score:1)

      by Anonymous Coward

      As we all know from thermodynamics, energy can be extracted from a temperature differential. And the Swedes' neighbours to the east are the Finns...

    • you forget their nominal condition, liquored up and red-faced radiating heat.

    • Re: (Score:2)

      by DeBaas ( 470886 )

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

      Maybe, but many of the women have really hot bodies!

  • 60W - 100W bulbs still commonly used? (Score:3, Insightful)

    by metamarmoset ( 2728667 ) on Monday December 31, 2012 @09:44AM (#42432079)
    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...

    • Re: (Score:1)

      by Anonymous Coward

      This is also a US-centric site, and in the US 82% of household lighting is still 40-100W incandescent, and US people are hoarding these light bulbs because of government mandated phase-out.

      • A crazy subset of US people are hoarding those light bulbs. Home Depot had the Phillips LED screw-in replacements on sale for $13 yesterday. No mercury, decent color temperature, expect them to last at least 25000 hours if you don't use them in a closed-up fixture, and probably longer.

        And you can always find some fool, ignorant of heat pumps and the inefficiencies of generating electricity, defending crappy old incandescent bulbs as a good source of heat.

        • Re: (Score:1)

          by Anonymous Coward

          Crappy old incandescent bulbs are a good source of "decent color temperature". The problem is that color receptors in the human eye have sensitivity curves over light frequency/wavelength, and colored surfaces have refractive curves. So even if your eye can be fooled into considering direct light from an LED light to have a certain color temperature, that does not mean at all that colored surfaces look the same color as they would under an incandescent light of the same temperature.

          It's the nightmare of p

        • expect them to last at least 25000 hours

          Or ~three months if you don't waste power by having them on 24/7. Power cycling kills them dead. Add being harsh on eyes and making colors look like crap (neighbour post can tell you more).

          • 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

            • You're talking about some fancy good LEDs that are either prototypes or can be found only in civilized parts of the world. Around here, all you can get are CFLs or cheapest chinese crap LEDs.

              I guess, I could hunt down something reasonable, but for now, incadescent bulbs just work. And their waste heat is welcome most of the year.

              • Where the heck are you? Home Depot stocks the Phillips LEDs, and all the parts I use are available mail order from an outfit in Vermont [ledsupply.com]. There are others, these are just the guys I stumbled across when I first set out to build bike lights.

                This stuff is not-not-not prototype -- I built my first set of lights in 2008 or earlier: http://dr2chase.wordpress.com/2008/10/19/more-undercabinet-lights/ [wordpress.com]

                The biggest problem is that the design point for incandescent bulbs is all different from LEDs, and trying to put L

                • A small town, Poland. I guess it's a combination of you painting things in way too rose colours and me in way too black, together with me not being up to date on new developments. For now I'll stay with something that works and has no downsides in my climate while you ahmericans figure a replacement out, but thanks for letting me know it's not as bad as I quite recently found out.

                  • So what's available in Poland? How much do they mark it up? CREE is American, which I think is wonderful and amazing, but I don't think the Chinese stuff will be crap for long. And how much does power cost in Poland, per kwH? That's what makes all the difference.

      • Re: (Score:2)

        by Lumpy ( 12016 )

        Mostly because a lot of us here in the usa are pretty dim, so we use higher wattage bulbs so we seem brighter than we really are.

  • Average bulb? Give me a break... (Score:4, Insightful)

    by markdavis ( 642305 ) on Monday December 31, 2012 @10:05AM (#42432169)

    >" 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.

    • That's the problem with analogies, they are based on something the majority is familiar with. ~80% of the population of the USA is over the age of 30. The incandescent bulb began it's phase out only a few years ago.

      There is a tiny insignificant portion of the population who can't rationalise what a 60 watt lightbulb looks like in terms of heat and light. Old people being especially resistant to change have no idea how much light or heat a 20watt CFL generates.

      Comparing something in power terms to incandesce

  • While they are at it let's install fart receptacles so that when a person feels a toot coming on they can plop their own asses on a hole to capture the methane for power plant use.....

    • While they are at it let's install fart receptacles so that when a person feels a toot coming on they can plop their own asses on a hole to capture the methane for power plant use.....

      You can't really trust people to properly fit the plug. Obviously we should simply replace the asshole with a quick-connect valve at birth. Hopefully a gate valve.

    • While they are at it let's install fart receptacles so that when a person feels a toot coming on they can plop their own asses on a hole to capture the methane for power plant use.....

      You could do that for cows. See this [phys.org] People don't really produce enough to make it worthwhile.

  • The Mall of America does a version of this.

  • that architects and builders are finding ways to capture this excess body heat on a scale large enough to warm homes and office buildings

    If you are in the building, aren't you already warming the building with your body heat, excess or otherwise?

    • If you are in the building, aren't you already warming the building with your body heat, excess or otherwise?

      Umm, yes. In this case you (along with a few thousand of your closest friends) are heating the building so much that the excess heat has to be removed. The point of the article is to put that excess heat that has to be removed to good use heating ANOTHER building.

  • Of those 100 travelers in a busy public space, about 8 are farting at any given moment.

    If that heat and gas could be captured, we might have an alternate energy revolution, especially within a few blocks of a Taco Bell.

    • Re: (Score:2)

      by cheros ( 223479 )

      Of those 100 travelers in a busy public space, about 8 are farting at any given moment.

      Finally, the smoking bans make sense ..

    • Re: (Score:2)

      by arth1 ( 260657 )

      Of those 100 travelers in a busy public space, about 8 are farting at any given moment.

      That would mean that on average, every person lets out a 4.8 second long fart every single minute.
      Unless they're all lawyers, that will by necessity produce a rather large volume of gas.

      That train station doesn't need a heat exchanger, it needs anchors.

  • Mall of America has been using body heat for years (Score:3, Informative)

    by MNNorske ( 2651341 ) on Monday December 31, 2012 @11:29AM (#42432737)
    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.

    • Re: (Score:2)

      by zaibazu ( 976612 )
      From at least least world war 2. Bomb shelters need to account for a lot of body heat on a small space.

  • WTF (Score:2)

    by tgd ( 2822 )

    If I paid for the food that made that heat, and paid to be in the space they're using to collect that heat, I'm sending someone a bill...

  • Usually whenever /. posts a story about harnessing energy from some source, the pseudo-physicists come out in force to complain about the energy being stolen, e.g. a story about harvesting energy from the motion of cars over a road attracts comments about stealing gas from the motorists (it must increase fuel usage, or the laws of thermodynamics are being violated, yada yada). Knowing /., I was expecting complaints about how this must increase food usage of the people in the subway. Kinda like how putting

    • I'm quite curious why you would mock or label as "pseudo-physicist" anyone who pointed out the foolishness of harvesting energy from moving cars. Perhaps the pseudo-physicist is between your ears.

      As for assisting HVAC heating with the human body, yes every building being heated, that also has people in it does that already, without one cent needing to be spent on additional equipment or infrastructure.

    • they're talking about moving heat, not converting heat. sure, there's an entropy gain with moving heat. but it's not nearly as large a penalty as you'd get from conversion. so, less to get angry about. Heat reclamation is just a form of smart design. hence all of the "this isn't anything new!?!" comments.

  • My 1926 house already has this feature. All of the heat given off by the bodies in the house going directly into the air and so the heater doesn't have to run as often. It's amazing what they thought of in 1926, before central heat was even invented. No wonder they're called the Greatest Generation!

  • That they were going to pump crowded train air directly into the office. Nothing else would quite keep the cubicle monkeys in their place quite like letting them know that free heat is worth more than lack of BO :)

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