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A Thermoelectric Bracelet To Maintain a Comfortable Body Temperature 125

Posted by timothy
from the oh-that'll-be-satisfying dept.
rtoz writes "Heating or cooling certain parts of your body — such as applying a warm towel to your forehead if you feel chilly — can help maintain your perceived thermal comfort. Using that concept, four MIT engineering students developed a thermoelectric bracelet that monitors air and skin temperature, and sends tailored pulses of hot or cold waveforms to the wrist to help maintain thermal comfort. The product is now a working prototype. And although people would use the device for personal comfort, the team says the ultimate aim is to reduce the energy consumption of buildings, by cooling and heating the individual — not the building. The team estimates that if the device stops one building from adjusting its temperature by even just 1 degree Celsius, it will save roughly 100 kilowatt-hours per month."
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A Thermoelectric Bracelet To Maintain a Comfortable Body Temperature

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  • by Bill_the_Engineer (772575) on Thursday October 17, 2013 @12:06PM (#45154475)
    Personal comfort involves more than just temperature.
    • by MightyYar (622222)

      And 1 degree C is pretty cold... ~

    • Any AC/Climate Control people know how the energy costs of modifying humidity compare to those of modifying temperature?

      For weedy little freestanding units, dehumidifiers appear to be pretty close to air conditioners that blow warm exhaust air in your face rather than outside; but there may be greater economies to be had in some mechanisms that only work on a larger scale, or when built into the building from day one, or so forth.
      • by MightyYar (622222) on Thursday October 17, 2013 @12:28PM (#45154763)

        At my office, we are all required to inhale the office air, but exhale through little snorkels placed throughout the office which exhaust to the outside.

      • by Anonymous Coward

        Hey, I'm AC. I've found that a pot of boiling water on the kitchen stove in the winter lets me keep my thermostat 3 degrees F lower and have the same apparent temperature. OTOH, in Arizona where the air is bone-dry they don't use many air conditioners, they have "swamp coolers" that lower the temperature by forcing air through a stream of water; the evaporating water cools the air. It's a lot cheaper since there's no compressor, but it won't work in many other places.

        • by Grishnakh (216268)

          OTOH, in Arizona where the air is bone-dry they don't use many air conditioners, they have "swamp coolers" that lower the temperature by forcing air through a stream of water

          You've obviously not been to Arizona in at least 20 years. No one uses swamp coolers any more because they don't work when the temperature is too high or the weather too humid. You'll see some older houses (70s-80s) that have piggyback swamp coolers + heatpumps, but no one builds houses like that any more, they've all gone to regular

      • by dj245 (732906)

        Any AC/Climate Control people know how the energy costs of modifying humidity compare to those of modifying temperature? For weedy little freestanding units, dehumidifiers appear to be pretty close to air conditioners that blow warm exhaust air in your face rather than outside; but there may be greater economies to be had in some mechanisms that only work on a larger scale, or when built into the building from day one, or so forth.

        At my old house (with central AC) I purchased a fancy thermostat with 7 day programming, 4 programming points per day, and the ability to take several remote temperature measurements and average them.

        Another feature it had was "humidity control". You could make a setpoint for humidity, and the AC would come on every now and then to maintain that humidity level. Temperature might have been 78F but with reduced humidity it was quite comfortable.

      • by jbengt (874751)

        Any AC/Climate Control people know how the energy costs of modifying humidity compare to those of modifying temperature?

        Depends on how you do it, of course.

        The typical pre-energy codes way was to cool the air below the dewpoint with a regular A/C cycle then reheat using electric heat (or another heat source, if readily available). That is very cheap to install but very energy-intensive.

        The "weedy little freestanding units" do essentially the same thing, but use the hot gas from the compressor to reheat th

      • by jbengt (874751)
        One other thing.
        You can improve dehumidification somewhat just by reducing the air flow of the A/C unit. You get a little less cooling, requiring the A/C to run longer, and reduce the temperature of the air significantly further below the dewpoint, ringing more moisture out. Of course, you can only go so far before running into problems so like freezing the coil or shutting down on safeties (if they're there), so YMMV.
    • The next version will include a small water tank with a sprinkler and a miniature hair-dryer.
  • Sold! (Score:5, Insightful)

    by i kan reed (749298) on Thursday October 17, 2013 @12:08PM (#45154497) Homepage Journal

    Give one to me to keep cool, one to my girlfriend to keep warm, and we'll set the AC in the middle.

    • Wait until she hits menopause... then you'll have to swap out that AC unit for a ginormous pile of dry ice.

    • by Anonymous Coward

      Give me your girlfriend to keep me warm and we'll be all set :D

    • Just inflate her with warm air.

  • by fiannaFailMan (702447) on Thursday October 17, 2013 @12:10PM (#45154529) Journal

    Quoth TFA:

    sends tailored pulses of hot or cold waveforms to the wrist to help maintain thermal comfort

    "Waveforms?" What does that mean? Does it work by convection, conduction, radiation or what?

    Personally I like the little space heater I keep under my desk. Makes it nice and cozy in winter. Much nicer than wrapping up with more layers.

    • Re:Waveforms? (Score:5, Informative)

      by RealGene (1025017) on Thursday October 17, 2013 @12:21PM (#45154691)
      Thermoelectric coolers are typically controlled with PWM, to adjust their temperature. The polarity determines which direction the heat is pumped, the duty cycle of the PWM determines how much.
    • I assume that 'waveforms' is a poorly-written-up allusion to the fact that a peltier element (while most usually driven in one direction for its entire life, or, as with those cheapie 'car fridge' units that plug into the DC jack and keep your no-it-isn't-beer-officer-it's-refreshing-soda cool; but can also warm things, flicked between running in one direction and running in the other quite infrequently) is a device that you would treat as demanding specially crafted AC current for a project like this.

      Be
      • Re:Waveforms? (Score:5, Insightful)

        by icebike (68054) on Thursday October 17, 2013 @01:32PM (#45155559)

        Once your follow the link from the self promoting blog to the actual article from MIT [mit.edu] you find this

        Over the course of developing its technology, the Wristify team made a key discovery: Human skin is very sensitive to minute, rapid changes in temperature, which affect the whole body. They found they needed to heat or cool any body part (in their case, the wrist) at a rate of at least 0.1 C per second in order to make the entire body, overall, feel several degrees warmer or colder.

        After 15 prototypes, the team landed on its final product, which resembles a wristwatch and can be powered, for up to eight hours, by a lithium polymer battery. This prototype demonstrated a rate of change of up to 0.4 C per second.

        The “watch” part of the prototype actually consists of the team’s custom copper-alloy-based heat sink (a component that lowers a device’s temperature by dissipating heat). Attached is an automated control system that manages the intensity and duration of the thermal pulses delivered to the heat sink. Integrated thermometers also measure external and body temperature to adjust accordingly.

        Its clear from the article that there is no actual heating of the body involved. Their system does not have enough power to heat 150 pounds of (essentially) water even one degree in the time period mentioned, let alone maintain any elevated temperature over 8 hours.

        They are simply tricking the body into thinking it is warm enough or cool enough so that you don't FEEL cold / hot. You still actually ARE too cold or too hot.

        This sounds interesting but I wonder just how safe it is to trick the body's thermal regulation its cool enough such that it no longer pays attention to the fact that it might be running dangerously close to heat induced stroke? Or trick it into thinking its cold, so it ramps up the metabolism.

        In fact this might be a more useful as w weight loss device than an energy saving device.
        But I'm still not convinced we should let engineers start micromanaging bodily functions, when all they are worried about is the device and the energy consumption.

        Technology to do the same thing was invented a LONG time ago. Its called a sweater.

        Even cheaper is a simple cap. Put it on, and you reduce heat loss through your head sufficiently enough to actually warm your entire body. Take it off and the reverse happens. The cap will last for years with no need for environment polluting batteries, and never has to be plugged in or recharged.

        • by denzacar (181829) on Thursday October 17, 2013 @02:25PM (#45156115) Journal

          Technology to do the same thing was invented a LONG time ago. Its called a sweater.

          It's keeping one foot out from under the covers.

        • You sound like Ebenezer Scrooge: http://youtu.be/QIcoa0oI5Cc?t=10s [youtu.be]

          It's not a favorable comparison.

        • by mattack2 (1165421)

          They are simply tricking the body into thinking it is warm enough or cool enough so that you don't FEEL cold / hot. You still actually ARE too cold or too hot.

          I thought this was obvious just from the summary.

          But yes, I too was wondering about this from a weight loss perspective. I've always wondered if you could make your body "think" it's too cold, so just burn up calories to "keep it warm". Yes, I realize being too hot is bad (e.g. a fever), but if you could somehow make the body just "waste" a little b

          • It fails the 'without making you sweat' test, and it will continue to work up to (and past) the point of lethal hyperthermia, which is why nobody officially uses it any more; but a href="http://en.wikipedia.org/wiki/2,4-Dinitrophenol">2,4-Dinitrophenol does the trick.

            The stuff craters the ATP synthesis efficiency of your mitochondria by allowing protons to pass through the membrane that is supposed to be maintaining the proton gradient for Oxidative phosphorylation. The energy that should have gone in
    • The thermoelectric elements work by the Peltier Effect. They're not as efficient as cartridge heating elements for heating or vapor compression refrigeration for cooling, but they also don't require moving parts and can be use in places where either of the more efficient mechanisms can't (like pressed against a gel pad pressed against a human body). They're a polarized device that pushes heat in one direction with current flowing in one direction and pushes heat in the opposite direction with an opposite
    • by tompaulco (629533)

      Personally I like the little space heater I keep under my desk. Makes it nice and cozy in winter. Much nicer than wrapping up with more layers.

      Yes, I would like to have one of those, too, but our office manager forbids it. Which is a shame because my office is on an outside wall and it is regularly 62 degrees Fahrenheit on mornings that are chilly outside, then by the afternoon, it is usually about 85 degrees.

      • by Grishnakh (216268)

        Yes, I had the same problem at a past job. That's why you put your space heater under your desk. Does your office manager run around looking under everyone's desk every day?

  • that powersaving claim might want to come with specs about the bulding for it to make any sense at all.

    Does it really cool you or give you just a cool feeling for a small while on your wrist? other is really easy to achieve and the other is really hard, edging on stillsuit territory. the heat has to go somewhere and I don't really envision carrying around 100watts+ worth of peltier cooling and a power source for that(with peltier efficiency at what, 10%? so I'd carry around a kw class power source?? or mayb

    • by jcochran (309950)

      Does it really cool you or give you just a cool feeling for a small while on your wrist?

      Neither, it instead tricks your body into thinking the overall temperature is comfortable.

      • by gl4ss (559668)

        but I could take drugs for that.

        Sure, I would pass out once the body got too warm and I had tricked my sweat glands to not work to keep me cool, so it would be rather pointless and maybe horrifying... which gets us to that the bracelet would have to either do that(block sweating) or not really work at all then.

        I'm starting to just assume that the inside of it gets just cool for a second("waves") or two. then it equalizes again in temperature and does it again. the problem with that is of course that you can

        • by geekoid (135745)

          It's not about cooling, it's about comfort. This isn't for Arctic or Sahara survival use. You could lower the temperature by 1C or so and still be comfortable. The overall saving in that is pretty big.

        • by icebike (68054)

          but I could take drugs for that.

          Sure, I would pass out once the body got too warm and I had tricked my sweat glands to not work to keep me cool, so it would be rather pointless and maybe horrifying... which gets us to that the bracelet would have to either do that(block sweating) or not really work at all then.

          Exactly. Our use a cap, or a sweater, or thinner clothing in hot weather.

          Letting engineers regulate the human body so that the building can be run on less energy is the perfect definition of ASS BACKWARDS.

          MIT should grow a Medical school instead of leaching off of Harvard. Perhaps then they might actually understand what they are messing with and perhaps grow to have a concept of ethics as well.

    • I tought somethng on the same lines, so I clicked on that link to RTFA. A mistake, obviously, since the article says nothing more than the summary.

      The one thing that I could see there (but not read, of course), is that there are wires running from the bracelet, it's not self powered. Not very practical, but answers your questions.

      • by icebike (68054)

        The real article is here: http://web.mit.edu/newsoffice/2013/madmec-design-competition-1017.html [mit.edu]

        (Damn slashdot editors allowing blog hyping instead of linking to the actual sources!!!)

        Close reading of that indicates this is just a huge trick played on the body's temperature regulation system.
        There is no actual heating or cooling of the body. Its probably dangerous at some level, and the body would
        also probably "learn" to ignore it.

        • And they beat a team that created an inexpensive solar cell and another that created a water filter that retains heavy metals, in a competition for sustainable technology, with that. Ok, it probably didn't consider how much the tech improved our footprint, just that it did improve, but even then, those other two are usefull.

          Now that I ranted, it looks like a great experiment that could lead to some usefull data about our body's temperature control. It just doesn't look like a product.

  • Sounds dangerous (Score:5, Interesting)

    by punkr0x (945364) on Thursday October 17, 2013 @12:16PM (#45154627)
    Isn't this basically tricking your body into thinking you're hotter or cooler than you really are? It might work temporarily but wearing this thing all day, every day sounds like it could mess up your body's ability to regulate your temperature.
    • Re:Sounds dangerous (Score:4, Interesting)

      by MightyYar (622222) on Thursday October 17, 2013 @12:33PM (#45154813)

      You are supposed to take some ecstasy to balance things out. They have a pacifier version, too.

    • Indeed - plus placebos generally don't work all that well when the person *knows* they're taking a placebo.

      • by unimind (743130)
        Actually, there have been some studies indicating placebos work regardless of whether the person knows it's a placebo. [npr.org]
        • by Anonymous Coward

          Placebos work really well for people who recognize the legitimacy of the placebo effect.

          By far the most potent medicinal combination is to educate a person on the reality of the placebo effect, and then give them actual medicine which you mislead them to believe is a placebo.

          I read theories that this is how Jesus actually brought people back from the dead.

    • by unimind (743130)
      That's what immediately occured to me. I'm pretty sure our brain does important things with the information it gets about temperature (and everything else for that matter). If the brain's perception of body temperature is decoupled from actual body temp, I would think results might be a little unpredictable.
    • Well, if I can trick my wife into thinking she is 'hotter' than she is, then we could well be on to something big.

  • Does it keep you from sweating? Say when the humidity is 90-100% and perspiration does nothing but soak your clothes?

    Wouldn't this kill your wrist after awhile? Especially if you're keyboarding? Perhaps an anklet?

    .
    • by idontgno (624372)

      Perhaps an anklet?

      Sure. They're coming up with an ankle version for the workplace environment. It comes attached to a 120 pound iron ball with a short segment of chain. You'll be cozy and secure at your galley oar ^w^w desk.

      • by sFurbo (1361249)
        Its not an iron ball, it's just the battery. It has to be bigger because the feet are usually cooler than the rest of the body, so more cooling is needed to make a difference, and we all know how inefficient cooling is. Preliminary testing showed it to be highly effective at increasing employee efficiency*.

        *Amount of time spent at desk was used as a proxy for employee efficiency.
  • by LongearedBat (1665481) on Thursday October 17, 2013 @12:40PM (#45154927)

    A few years ago my gf got an infection that now causes her to get rashes whenever she's warm, and being hot makes her skin terribly itchy. (Please don't bother with sordid jokes here. They're too easy, I'm tired and I'm actually being serious.) So far she's had to resort to taking antihistamines almost daily, and she's likely going to have to do that for the rest of her life.

    This bracelet doesn't actually cover the body, so it's not actually making the skin cool. And I don't understand what the mean by waveforms across the skin. Does that mean it's telling the skin that it's cool/warm even when it's not?

    So I'm wondering, could this be something to help her feel cool, and thereby less itchy, especially during summer?

    • by EvilSS (557649)
      This would not help your GF. However, to understand the principle, next time it's hot out, go outside and place an ice cube on the underside of your wrist.
      • by Grishnakh (216268)

        What I want to know is how much this actually affects the body's temperature. When you're really hot, one way to cool down is to put an ice cube on your forehead and on your neck, over your carotid arteries. This isn't just a trick; there's a lot of blood flowing through those spots on your body, so if you cool them down with an icecube, you're also cooling your blood, which of course cools your whole body because of the circulatory system. I imagine the same effect works with your wrist, but not nearly

        • by EvilSS (557649)
          It won't, and neither will your ice cube (try it with a oral thermometer if you don't believe me). They lack the mass and cover too small of a surface area to make a dent your core body temp. If they could you probably wouldn't want it touching you, think about the amount of energy that would have to pass through a very small spot on your body to lower your body temp by even a fraction of a degree. That would not be comfortable at all.

          Instead, your brain prioritizes extremes in sensory input like tempe
    • by geekoid (135745)

      Maybe, but if it does it would be a pretty strong indicator that her issue may be in her head. That's not a judgement.

      If it was an infection, she could actual be experiencing another bacterial infection of folicles. Antibiotics should help that.

      http://www.ifd.org/protocols_bacterial.htm [ifd.org]

      • Yep, probably in her head. Like in her hypothalamus [unl.edu].

        And, more to the point, it might help the OP's GF's rash. Although some icy hot or an ice cube might be a good trial device and quite a bit smaller than the prototype.

    • by glitch! (57276)

      It sounds like her immune system is pretty messed up. I would make fixing that a priority so it doesn't get worse, or allow some future infection to blossom.

      Somewhere, there must be a medical doctor that can figure out the cause, and get it fixed. At the very least, I would suggest vitamin D (2 x 5000IU) and vitamin C (2-10 grams, or as much as the body will take before laxative effect.) That should be safe and may give some relief.

  • ... the team says the ultimate aim is to reduce the energy consumption of buildings, by cooling and heating the individual — not the building.

    Bullshit. This device does nothing of the sort; instead it tricks the body into thinking the ambient temperature is just right when in fact it's not. Those nerves and body temperature regulation systems exist for a reason, and tricking and preempting them to save corporations money is sickening.

    • by whois (27479)

      Maybe not. Your wrist has major arteries (veins? I dunno) close the the skin. Placing something to cool you there will cause the blood to carry it throughout your body.

      I found out someone had made a peltier cooler for a person who can't sweat a while back. I wanted one so I google searched for it but apparently nobody makes them. Hopefully the MIT guys will actually come up with a cheap product for everyone.

      • by macraig (621737)

        You'd have a distractingly hot/cold wrist at the very least if that had any hope of doing what you suggest. That's in any case not the goal of what is described.

      • Nope, if you read the articles, it is trickery. To change your whole body temperature, you need an prolonged contact with a cold object to those veins. This thing is not warming or cooling you, it just fluctuates its temperature in such a way as to make you think you are warmer or colder than you really are.

        This sounds dangerous to me.

        From the articles linked it looks like they give you a quick pulse in the direction that you want to perceive and then gradually return the plate to normal so they can give yo

    • by geekoid (135745)

      Save everyone money, more inmportantly save energy.

      If you could keep the temp of your home 2 degrees cooler or warmer, thus saving you money.

      • by macraig (621737)

        You're missing the point: if the body is tricked - as this technique aims to do - into thinking the ambient temperature is tolerable when it's really not, that likely has a health effect. That part of the nervous system exists for a reason. As that ancient commercial declared, "it's not nice to fool Mother Nature!"

        • by mattack2 (1165421)

          That part of the nervous system exists for a reason.

          You could say the same thing about hay fever or other allergies, yet in day to day life, they aren't actually saving people from anything.

          • by macraig (621737)

            Allergies are a dysfunctional immune system response, not a normal constructive one. This device is not targeted at people with dysfunctional sensitivity to temperature, unless we conveniently reclassify any response to temperature as dysfunctional.

  • I will stick with my beer hat with the clip-on fan and mister.

  • by bananaquackmoo (1204116) on Thursday October 17, 2013 @01:17PM (#45155381)
    Am I missing something? Isn't this the exact same thing as putting on or taking off clothes?
  • I have a cheaper system that involves a fan and a jacket.

  • Free alternative (Score:4, Insightful)

    by pla (258480) on Thursday October 17, 2013 @01:24PM (#45155477) Journal
    How about just letting most of us work from home, and only maintaining enough office space to host a handful of meeting/collaboration rooms? Bam, your whole "office building" just reduced to a 2nd story loft.

    But hey, sure, let's instead try playing games with peoples' heads rather than address the real problem. And then the PHBs can ask themselves why the electric bill has actually gone up, when everyone starts keeping an electric space heater under their desk.
  • by PPH (736903)

    Anecdotal evidence: After having installed a radiant floor heating system, I made the following observation. If your feet are cold, you perceive the environment as being cold. And you turn up the heat. If your feet are warm, you can tolerate lower air temperatures.

    This might be related to the rate of heat loss through contact. Where heat loss to air (via convection) is inefficient, loss through conduction is higher. Since the one point that is most often in contact with another surface is your feet, minimi

    • Anecdotal evidence: After having installed a radiant floor heating system, I made the following observation. If your feet are cold, you perceive the environment as being cold. And you turn up the heat. If your feet are warm, you can tolerate lower air temperatures.

      Wrists, ankles, and neck.

      These are the main points by which your body measures ambient temperature, and makes adjustments accordingly. Theoretically, if you were to wrap your wrists, ankles, and neck in some sort of warm material, you could very well walk out into near-zero temperatures otherwise naked, and not really feel the cold. Anecdotally, I tried this myself last winter (albeit with the addition of skivvies to avoid an indecent exposure charge), and I do recall noting that I didn't feel as cold as I

  • Did it like 15 years ago, which I assume was some sort of product placement.

  • Sigh. A few years ago (2005, actually) I played around with a Peltier junction body part warmer/cooler but did not carry it past a prototype. My idea was to take the place of hot/cold pads on sports injuries, help with backaches, etc. The idea was that this unit could replace both ice packs and hot pads, and even cycle between them, and provide the heat or cold at a precise temperature for a long time. I still have the prototype stuck in a box somewhere. It actually worked, but the hardest thing was g

  • Two reasons. The obvious one is that a lot of employees will balk at wearing the device.

    The slightly less obvious one is the state of HVAC systems in many office buildings. The last building I worked in was straight out of Brazil. I had a thermostat on my wall that controlled the AC for my corner of my floor. Not the heat, tho. Every fall, people would lean in my office and ask me to turn up the heat. I'd explain over and over that I can only make it colder. They're welcome to look at my thermostat's

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