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China Science Technology

Building Material Absorbs and Releases Heat 98

Posted by samzenpus
from the cool-house dept.
Zothecula writes "Researchers at the Ningpo, China campus of the University of Nottingham (UNNC) have created a new heat-regulating material that could be used to cut the heating and cooling costs of buildings. The non-deformed storage phase change material (PCM) can be fixed so that it starts absorbing any excess heat above a pre-determined temperature and releasing stored heat when the ambient temperature drops below the set point. The researchers say the material can be manufactured in a variety of shapes and sizes, even small enough so that it can be sprayed as a microscopic film to surfaces in existing buildings."
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Building Material Absorbs and Releases Heat

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  • by Anonymous Coward

    I'm pretty sure that almost every substance on earth "absorbs and releases heat".

    • Unless... (Score:5, Informative)

      by Vario (120611) on Wednesday August 03, 2011 @08:17PM (#36979754)

      Yes, every material absorbs and releases heat.

      The interesting bit here is something different though. I have never seen that someone wants to use a phase change material for buildings, but why not? For coffee cups this already works nicely. The walls of the mug contain a material that is undergoing some phase transition (liquid to solid, different crystalline structure, magnetic, etc.) at a temperature that is slightly below really hot coffee but still a nice drinking temperature.

      What happens is the following: the thermal energy of the coffee gets absorbed quickly by the material, therefore cooling it down fast from really hot to a lower temperature. The material can store a large amount of thermal energy and releases it slowly so that the coffee stays at a constant temperature for much longer (gizmag article [gizmag.com]).

      For a whole building this makes a lot of sense as well. It more or less acts as a large thermal reservoir, so that your wall temperature does not increase during the day and falls too much during the night. You could achieve a somewhat similar effect by using 20 inch stone walls but this might be a bit easier to incorporate into modern buildings.

      • Re: (Score:2, Informative)

        by Anonymous Coward

        It's been done for a long time.
        Southern yellow pine resin has its phase change at about 71F. The first reference in google is from 2007 but it's been know about for a long time before that,

      • by jbengt (874751)

        I have never seen that someone wants to use a phase change material for buildings . . .

        Ice is a phhase change material that has been in use for a long time.

        • Alas, the phase change to liquid does render it less suitable for buildings. Perhaps you meant that ice (or even better, packed snow) has long been used in cold climates for its high insulation value?
          • by jbengt (874751)
            No, but ice has long been used in cooling systems to reduce the peak demand and take advantage of lower night-time temperatures.
          • Mod up!

            I live in Winnipeg, Canada and two winters ago my basement's record low was 8C. Last year I did two things: First I repaired the fascia covering the front of the house's foundation using $20 worth of spray foam and plaster crack fill. (did wonders for drafts). I also banked up the snow around the house 4 to 5 feetr high. I think the lowest temperature down in my basement was 15C.

      • What happens is the following: the thermal energy of the coffee gets absorbed quickly by the material, therefore cooling it down fast from really hot to a lower temperature. The material can store a large amount of thermal energy and releases it slowly so that the coffee stays at a constant temperature for much longer (gizmag article [gizmag.com]).

        Actually, that article specifically mentions that PCMs are currently in use as building materials. Interesting.

    • Certainly, but I imagine is when it absorbs and when it releases. Heavy stone and ceramic seems to be the best here. If you look at old buildings you will see the benefit since they absorb the heat when hot and release the environment is cooler.

      I haven't read the article yet, so I would be curious to see how complicated and how much better it is over existing materials.

      BTW one thing I have been looking at is paint with ceramic beads. The problem I have with it at the moment is cost and availability in Canad

  • by Jeremiah Cornelius (137) on Wednesday August 03, 2011 @07:57PM (#36979544) Homepage Journal

    Whoa! Just like... matter!

    Can I patent this thermodynamics stuff?

    • by Richard_J_N (631241) on Wednesday August 03, 2011 @08:08PM (#36979656)

      If it performs a phase change at a specified temperature, it means that there is a lot of extra thermal "capacitance" at one particular temperature. If we can choose that temperature to be, say 20 degrees C, this is useful. It would be a bit like water ice. As the freezer temperature falls from +1 to -1 degree, the ice releases a *lot* of stored heat (latent heat of fusion).

      So, yes, this is a bit like building a large stone structure, which stays at a constant comfortable temperature by averaging out cold nights and hot days...but we don't need so much mass, and we can choose the temperature we want.

      • by Anonymous Coward

        This is only helpful if you have constant temperature changes. If you live someplace where it's 80 during the day, and 60 at night, and you want it to be 75, this could help. However, if you live someplace where even at night, it's hotter than you want it to be, this does no good at all. It's not going to be able to store up a whole summers worth of heat to release in the winter. During the time period between needing heat, and needing AC, we generally just leave the heater and ac off, and deal with the tem

        • by lessthan (977374)

          What? There aren't many places that don't have temperature changes. I live in Pennsylvania. Tomorrow is forecast to have a high of 86 and a low of 67 (or a high of 30 and a low of 19 if you are measuring properly). That sounds like a proper variance to me. I imagine that any desert or temperate location would benefit from this material. Tropical and polar locations would be screwed, but who cares about Greenland?

          • by sgt scrub (869860)

            Tomorrow is forecast to have a high of 86 and a low of 67

            First, as a Texan with an air conditioner strapped to his ass in a loosing battle to stay below 100 degrees, I would like to say, "I hate you". Second... No. That is all I wanted to say. :p

      • Re: (Score:3, Informative)

        by icebike (68054)

        Nothing new here.

        Phase change applications were fairly commonly installed in houses back in the late 70s. Usually a liquid to gel phase change but some were liquid to solid.

        The problem then as now, was finding something that changed at the desired temperature, because any time you have to concentrate the heat to reach the the temperature where phase change occurred you lost much if not all of advantage of using these materials. (You essentially ended up running a air-source heat pump to concentrate hot ho

        • by Culture20 (968837)
          Heck, Eskimos used a solid/liquid phase change material for even longer!
        • by godel_56 (1287256)

          Nothing new here.

          Phase change applications were fairly commonly installed in houses back in the late 70s. Usually a liquid to gel phase change but some were liquid to solid.

          The problem then as now, was finding something that changed at the desired temperature, because any time you have to concentrate the heat to reach the the temperature where phase change occurred you lost much if not all of advantage of using these materials. (You essentially ended up running a air-source heat pump to concentrate hot house air into the material).

          Yeah, here's two more: http://www.gizmag.com/ravenskin-insulation-delays-heat-transfer/17056/ [gizmag.com] http://www.fraunhofer.de/en/research-topics/construction/microencapsulated.jsp [fraunhofer.de]

          I think the second one looks cheap and interesting. They use a micro-encapsulated tailored wax which can be mixed into plaster wall boards, giving them the thermal capacity of a brick wall.

        • by geekoid (135745)

          Other then its smaller, lighter and more efficient, yeah nothing new~

        • by mattack2 (1165421)

          It was pathetic compared to water.

          Within the past year or two there was a house for sale whose owner had died. He was apparently known in environmental circles. The house had water jugs on levers that you could tilt up or down to catch the suns rays, then close it up and have the heat come into the house at night. (It also had a roof water heater, and one of the other people looking at the house said the temperature on the roof water heater was very high, but I don't remember what temp it was.)

    • Can I patent this thermodynamics stuff?

      You can try, but I think the fact that the Universe exists just might be considered prior art.

    • Re: (Score:1, Insightful)

      by Anonymous Coward

      No, not just like "matter", you fucking moron.

      Since when did, say, a piece of concrete not release stored heat until the ambient temperature drops below a set point? Because, last I checked, normal materials release heat the minute the ambient temperature drops below the material temperature.

      Honestly, with your low UID, I would've expected you to have functional reading comprehension skills. Maybe it's time to see a doctor about your old age dementia, there, old timer.

    • by Raenex (947668)

      Can I patent this thermodynamics stuff?

      No, but you can get modded up for posting a shallow comment that applies to the headline only. Maybe if you weren't rushing to get the first post in you could have at least read the summary.

    • These Phase Change Materials are different from other matter. They absorb heat without changing their temperature.

      So as the heat energy increases in a room - say, when sunlight shines in a window, or hot air circulates in - the energy is absorbed by the PCM instead of heating the regular matter in the room. So the energy increases, but the room's temperature doesn't. Instead, the heat energy changes the phase of the PCM. So work is done by the energy, just not work that increases temperature. Which means a

      • First off, ALL mater absorbs energy while undergoing a phase change. During that time, they are not changing temperatures. Once the phase change is done, then the temp will change.
        Likewise, phase change is not a big deal. The issue is that it moves from solid to liquid. At time of changing to liquid, it will have to interact with another material to stay stick around or be in small micro bubbles that are attached.
        • by Doc Ruby (173196)

          Not all matter undergoes phase changes while heated, and not all in the same way. Very rare is matter that can have its phase-change temperature tuned to a required point the way this stuff. Also unusual is the phase change holding such a large amount of heat per mass, especially without deforming the way this stuff doesn't.

          This stuff is revolutionary.

    • You're probably much too late. I suggest contacting Intellectual Ventures for a license.
  • Link no worky. False link.... Its a TRAP!
  • Its all about bringing the state change into a temperature zone that can utilized, and it has to be cheap.
    Damp Magnesium Sulfate always worked for us.
  • How does it react to common hazards ... such as fire? Boom? If it goes up like a pine tree then it isn't very good, imo.

  • No credibility (Score:4, Insightful)

    by MrQuacker (1938262) on Wednesday August 03, 2011 @08:11PM (#36979688)

    After all the articles about plagiarized and outright made up research in Chinese universities, I have to take every "discovery" they announce with huge skepticism.

  • Limited utility (Score:3, Interesting)

    by rgmoore (133276) <glandauer@charter.net> on Wednesday August 03, 2011 @08:15PM (#36979732) Homepage
    Note that this kind of material only works to increase the heat capacity of the building, so it will only work when the temperature fluctuates across the phase change temperature over the course of the day. You'll still need a heater if it gets cold and stays cold and an air conditioner if it gets hot and stays hot. The big benefit is that the heat capacity only applies across a narrow temperature range, so it's relatively easy to maintain that temperature passively.
    • by icebike (68054)

      You are presuming that heat would be extracted from the house during the day. But that is not always necessary, and as you suggest, not very efficient.

      An external solar collector working at temperatures much higher than would be comfortable is actually more efficient. Roof mounted collection, and underground storage may be able to collect enough in summer to cover a month or two of fall heating. With such a setup, you can pick a phase change material based on its storage capacity, and be less constrained b

    • Re:Limited utility (Score:5, Informative)

      by sjames (1099) on Wednesday August 03, 2011 @09:30PM (#36980386) Homepage

      It has limits, but it can save a LOT of energy. In some environments such as a desert, the average temperature is quite nice, but unfortunately it swings from freezing to over 100, so you need a good thermal mass to enjoy that average.

      In other cases, the average temperature will not be comfortable, but a thermal mass can still save energy. For example when heating is needed, you can run a heatpump during the warmest part of the day when it runs more efficiently and rely on the mass during the coldest part.

      All that said, thermal mass is nothing new, but the phase change at a useful temperature is an improvement on it.

      • Not just the desert. I live in the northeast US, temperature fluctuations in the spring and fall can be 30+ degrees in a matter of hours. If I packed my walls with this stuff set to phase-change at 65F, I could probably go until December before turning on the heating system. In the summer, it would probably totally negate the need for air conditioning (not that I have it anyway), since nights tend to be below 65 even when days are in the 90s.

        The big question I have in terms of practical use in a retrofit re

        • by sjames (1099)

          The condensation is a good point. I don't know just what would be best, but something would have to be done about it.

          It might be best to use it as a standalone thermal mass rather than building it into the walls. Then the box that holds it can have a proper condensation drain like an air conditioner. That negates some of the advantages, but it might still be useful.

  • by Relic of the Future (118669) <dales@@@digitalfreaks...org> on Wednesday August 03, 2011 @08:19PM (#36979770)
    Yes, quick-but-not-entirely-wrong posters, everything absorbs and releases heat. The only reason this is interesting is because of the "PCM" part. If you actually recall your high-school physics, as heat is absorbed by an object, its temperature rises, UNTIL it reaches a phase transition; then the temperature stays constant until the phase change is complete. You probably did this with ice and water. The temperature of a chunk of ice starts below 32, increasing linearly with time, then it stops right at 32 and stays there until all the ice was melted, when it begins increasing linearly again.

    This is useful for maintaining a consistent temperature inside when the outside temperature is bouncing above and below the temperature of the phase change (say, between day-time and night-time) rather than always needing to heat when it's cold and cool when it's hot. The PCM "building material absorbs and releases heat" automatically, in theory lowering your energy bills.

    The neat thing--and yes, this IS neat--is a) this material is tunable; you can set the phase transition temperature at time of manufacture and b) it doesn't turn into a liquid, but rather changes between two different solid phases, which is nice for things like, you know, walls, that you'd like to stay solid.

    And you were all so excited by this idea when Wozniak was pushing it in 2007; he'd latched onto a certain species of wood whose sap underwent a phase change at 72 degrees. Build a house out of that, and it will tend to keep the inside temperature at a Woz-friendly 72 degrees.

  • for thousands of years.

    I wonder how much the material out gasses...

    • Also, adobe. I know in certain places in Mexico, many of the older adobe homes don't even bother with AC, while the newer ones can't keep up with the heat.

      • Also, adobe. I know in certain places in Mexico, many of the older adobe homes don't even bother with AC, while the newer ones can't keep up with the heat.

        The BSA is on their way to Mexico now, thanks. Never mention Adobe.

  • This material is consuming heat energy to perform the work of dis/organizing its molecules without its temperature increasing. That sounds like a (maybe just nearly) perfect nanomachine powered by heat. If the mechanical work can be powered by heat to do useful matter movement, like microfluidics or even nanoassembly, we might have found a device that can use our too-abundant waste energy (heat) for some of our most useful tasks: chemical manufacturing. Maybe even nanocomputing, pushing molecular rods or fl

  • welcome to thousands of years ago

  • Very similar systems are being developed to aid A/C units in cars with stop/start engines: http://www.sae.org/mags/aei/9864 [sae.org]
  • How is this "invention" different from the established product BASF Micronal which has been available for a couple of years?

    http://www.basf.com/group/corporate/en/brand/MICRONAL_PCM

  • This looks all quite well and promising, but there are no numbers. I wonder how much more heat capacity this material has wrt, say, brick or water.

    Yeah, I know, Infinite! It's a phase transition where the temperature doesn't rise at all with heat added. Or rather, close to infinite (sorry, my fingers ache as I write this, but I hope you get the idea). I remember measuring spikes in Cp and Cv for hours and hours in undergraduate physics lab, and plotting it out on millimeter grid paper with a pencil. Ah, th

    • by sgt scrub (869860)

      Oh man. I was on a rant then looked up to see your post. I hate when that happens.

      That is nice that they discovered... material? It would help if they released some data showing things like maximum potential heat retention, temperature resistance, release rates, etc... Is it like glass, marble, copper, a vacuum? I mean wtf good is, "it stores heat and releases it later"?

    • Ice will keep liquid water at 0 degrees centigrade at standard pressure for temperatures from 0.1C to 5,000,000C - it's just a question of "How long?". I imagine it's the same with this material. What is the phase change enthalpy and how much material is there = how long it maintains that temperature and how long a "reset" takes.
  • After i finished spray painting my sky scraper with all my solar cell paint to catch all the light and heat ....now i can spray paint another coat on top of it, and have duplicate layer technology that will allow for me to have more heat or less, and still give me my electricity?

  • Suppose that this material had a phase change specific heat comparable to the liquid/solid change of water. 330 kJ/kg.

    By comparison the specific heat of water is only 4 kJ/kg

    Let's consider a house 20x40 feet with R30 walls and an R40 ceiling.

    It has 120 linear feet of wall x 8 feet high so it has roughly 1000 square feet of wall. At R30 that's 33 btu//hr/F. The ceiling is 800 square feet at R40 so it's 20 btu/hr/F. So our cute windowless box takes 53 btu/hr/F

    In 12 hours it will use 640 btu/F. I chose 12

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