11 ms·
A film that can cool buildings without the use of refrigerants
- jrockway 10y agoI have fifty cents. Where can I buy a square meter of this from?
- _rpd 10y agoIt was only just described in a Science paper, so you are probably going to have to wait 10 years before you can buy it at your local hardware store.
- waqf 10y agoSo, in what sense is it true that it costs (present tense) 50¢/m²?
- lovemenot 10y agoMaterial costs at hypothetical production scale.
- amalcon 10y agoIt's a manufacturing cost estimate, not a market price.
- yellowapple 10y agoIt seems reassuring that there's already a manufacturing cost estimate and that it's as low as 50¢/m².
- pbhjpbhj 10y agoPatents will ensure it sells for $100 per square-meter though, or whatever ludicrous price can be burn by the market and still make it valuable to the consumer.
- woodandsteel 10y agoI could be wrong, but the film is described as so simple that it seems like it could be in commercial production a lot sooner than that.
- gewa 10y agoHow is this not violating the second law of thermodynamics ? It seems like the entropy as a whole is getting lower.
- milcron 10y agoDid you read the article? The new film works by a process called radiative cooling. This takes advantage of that fact that Earth’s atmosphere allows certain wavelengths of heat-carrying infrared radiation to escape into space unimpeded. Convert unwanted heat into infrared of the correct wavelength, then, and you can dump it into the cosmos with no come back. the work is done by the huge temperature difference, about 290°C, between the surface of the Earth and that of outer space.
- a_t48 10y agoCould we cover large portions of the Earth with this material and reverse global warming?
- monochromatic 10y agoProbably wouldn't be cost-effective, but it'd work in principle.
- dreamcompiler 10y agoIf you floated thousands of square miles of it on the surface of the oceans, yes. But that first assumes a reasonable time payback of the CO2 burden of manufacturing the stuff in the first place, which is not a given. It's obviously not practical for oceans, but it might protect ice caps and glaciers.
- caf 10y agoBecause it's radiating the heat out into space, you need to consider the entropy of the complete Earth-Space system, which is actually increasing.
- deleted 10y ago
- voltagex_ 10y agohttp://science.sciencemag.org/content/early/2017/02/08/science.aai7899 http://science.sciencemag.org/content/early/2017/02/08/scien... is the paper linked in the article
- Retric 10y agoDid not read the article, but the abstract is misleading. It does not matter if the atmosphere absorbs the radiation from your device or it reaches space, after a few feet it's irrelevant. The important bit is the underside of the tarp which is not going to be below ambient temperature. Making the absolute best it can do the equiviemnt of a fan on the roof which can't replace AC.
- rickdale 10y agoMaking the absolute best it can do the equiviemnt of a fan on the roof which can't replace AC. You are right it won't replace the AC, but the technology could lead to a reduction in overall AC use.
- Retric 10y agoOnly as much as some tarps over a building and a fan 'cooling' the AC's evaporator coils. Don't get me wrong it's a neat effect, just not particularly useful.
- woodandsteel 10y agoIf you covered things like parking lots and sidewalks, it would reduce the heat island effect and hence air temperature, and so reduce AC some more.
- baldfat 10y agoThe same reason why cities plant so many trees. https://www.epa.gov/heat-islands/using-trees-and-vegetation-reduce-heat-islands https://www.epa.gov/heat-islands/using-trees-and-vegetation-...
- 10y ago
- sqeaky 10y agoSeems innovative and awesome if true, but it is not so awesome as to be without issues. Clearly this is great for places that are always warm, slap this stuff on every building in Texas. But what about places with erratic weather, or even just seasonal changes? It seems like this will need to be some way to flip this stuff.
- wccrawford 10y agoThe article says that the material is only half the solution. The other half is pipes with water to move the heat to the material so it can be dissipated. I assume that if you stop moving as much water, it doesn't cool as much. (It can't radiant heat that isn't there.)
- asafira 10y agoSo that's definitely a limitation, but I wouldn't call it an issue --- this would have plenty of application!
- mrfusion 10y agoThis would be awesome to put on cpus.
- elbigbad 10y agoDon't CPUs not usually play friendly with water?
- wallacoloo 10y agoThe water exists only to transfer the heat over distance. If the heat sink and heat source are in direct contact, then no need for water.
- euyyn 10y agoI expect the radiated IR would just heat the device around the CPU. It's not like CPUs usually face outer space.
- ars 10y agoThis only works because the sky does not transmit much energy at the particular infrared frequency this operates at. In contrast ordinary objects (the computer case, a tree, a wall), do transmit those frequencies. This would have no effect - it's absorbing the frequencies emitted by the wall, and transmitting to the wall, the net effect is zero. i.e. it only works under open sky. I suspect even clouds would block this from functioning. (Not sure about this - maybe water has a "window" at this frequency?)
- deleted 10y ago[deleted]
- asafira 10y agoYou are actually totally correct, clouds would worsen cooling power.
- yellowapple 10y ago
- mrfusion 10y agoAlso it would make a great clothing to wear in the summer or on a spacecraft heat shield.
- averagewall 10y agoIt wouldn't be useful on a spacecraft because it takes advantage of a transparent band in the Earth's atmosphere. In space, you have that already at all wavelengths.
- cgriswald 10y agoMore to the point, a heat shield is used for re-entry and this stuff would decompose almost instantaneously. It's be like trying to use a handheld fan to cool yourself while standing in a kiln.
- stuaxo 10y agoThis would be great in hot countries, where so much energy is used in air condition, it could make a real dent in energy use, and hence pollution.
- tajen 10y agoNot only that, but the energy is radiated in wavelengths that aren't absorbed by the atmosphere (I suppose it's different with cloudy skies). If this solution becomes massively widespread, it could have a good effect on global warming. With caveats: If we imagine a city radiating all its energy as infrared, it could cause weather abnormalities.
- awqrre 10y agoisn't air temperature control the largest energy expense in most countries' homes?
- tajen 10y agoI'd be curious about France for example, since air conditioning isn't as widespread as in Germany, Thailand or USA.
- Baeocystin 10y agoYes. Although IIRC it is heating, not cooling, that consumes the lion's share. But the general point stands.
- vanderZwan 10y agoIn that sense storing heat underground in summer and pumping it up in winter might be a better option.
- sfifs 10y agoMost homes in hot countries are not cooled with air conditioning because most people in hot countries are too poor to afford it. Even the rich 1% tend to use air conditioning only on a room by room basis, almost never the whole house.
- lovemenot 10y agoHow lovely that the two inventors are Doctors Yin and Yang. Presumably Dr. Yin was responsible for energy absorption and Dr Yang for energy emission.
- azinman2 10y agoOmg amazing. Good find! :)
- clort 10y agoI saw this and smirked internally of course, but noticed in the article itself they did refrain from trivialising the names of the inventors in this way, by referring them to Dr Yang and Dr Yin throughout.
- Udik 10y agoApparently, they improved on the work originally done by Dr. Fan in 2014.
- agumonkey 10y agoAdd them to wikipedia aptronym list.
- caf 10y agoA "reverse pool blanket" made of this material would be great for places where swimming pools get unusably hot in summer.
- sfifs 10y agoare there such places on earth where people live? I live in India and haven't come across such :-)
- adiabatty 10y agoDeath Valley, California. I tried swimming in a pool there once and it was like swimming in a jacuzzi.
- caf 10y agoFar North Queensland is one I've been to.
- andrewwhartion 10y agoSwimming in a concrete/Pebble Tec pool in Cairns in the summer is akin to taking a warm bath...
- sparrish 10y agoIn Phoenix AZ, July/Aug/Sept pool parties are often BYOBOI (bring your own block of ice). Everybody brings a 10 lb. block of ice to throw in the pool and within an hour it's cool enough to enjoy, even in the 115F heat.
- dxhdr 10y ago"50 micron thick polymethylpentene mixed with tiny glass beads" As an achievement in science this is cool, but... we should be reducing energy consumption while also not polluting the surface of the planet. Where's this stuff going to end up when houses covered with it are torn down in 30-100 years?
- pdonis 10y agoRecycle it.
- dxhdr 10y agoWe don't recycle microplastics for a variety of reasons, that's the reason I bring the issue up. Current theory is microplastics end up in our food.
- pdonis 10y agoAs I understand it, "microplastics" are small particles of plastic, not thin sheets of it. The sheets should be easier to reprocess than small particles would be.
- asafira 10y agoTo be clear, this is actually a very small amount of plastic. Let's say a roof is 300 square meters; that amounts to < 2 cubic centimeters of plastic. I would guess that there are examples of much larger consumers of plastic.
- DiabloD3 10y agoThat'd make it far less plastic than is currently used for roofs just for the vapor barrier under roofing tiles.
- woodandsteel 10y agoThis is really cool (pun intended). I wonder if you could integrate it with a solar cell, so you would get both cooling and electricity. It would be nice if they could figure out how to turn the effect off at the film, instead of having to pipe water.
- ph0rque 10y agoHave another film above it that can be switched from reflective to transparent? These already exist, but are made of exotic materials (vanadium oxide, if I recall correctly) and thus expensive.
- CamperBob2 10y agoI'm not sure I get how the beads re-radiate energy at 8 microns that came in at other frequencies. If the energy didn't come in at a different frequency, then the building isn't going to end up any cooler. If it did, then the beads are essentially phosphorescing in the IR region, aren't they? Or exhibiting some other form of nonlinear conversion? That would be pretty cool, no pun intended.
- Gibbon1 10y agoI would believe that the heat energy gets transferred to the beads by conduction and or radiation. I tend to think this is like a gas mantle in a gasoline (propane) lantern. The mantle is doped with rare earth that emit more strongly in the visible section than a black body would. On this case the temperature is much lower of course and the glass beads are sized to emit strongly in an the infrared band that isn't absorbed by the atmosphere.
- sfifs 10y agoI don't know about this particular technology but as a parallel all Florescent Lights operate on a similar concept. They absorb radiation at frequency X and emit in frequency Y where Y is visible light. It appears that the researchers have tuned the emission to a frequency that is not reabsorbed by the atmosphere but emitted unimpeded into space. Pretty clever engineering.
- samch 10y agoI'm not entirely sure about the mechanism, but it appears to work via phonon-polariton resonance: https://en.wikipedia.org/wiki/Polariton https://en.wikipedia.org/wiki/Polariton So, couple this, in terms of the dispersion of energy: "Our hybrid metamaterial is extremely emissive across the entire atmospheric transmission window (8-13 μm) due to phonon-enhanced Fröhlich resonances of the microspheres." And this in terms of the absorbtion: "In the case of large microspheres, modal interference between higher order modes makes the hybrid metamaterial strongly infrared-absorbing." And finally this in terms of reflectance: "The hybrid metamaterial strongly reflects solar irradiation when backed with a 200-nm-thick silver thin film prepared by electron beam evaporation... The measured spectral absorptivity (emissivity) of the sample (Fig. 3D) indicates that the 50-μm-thick film reflects ~ 96% solar irradiation..."
- garrettgrimsley 10y agoA perfect example of how a low-effort and non-substantiative comment can rise to the top as long as it is amusing.
- toomuchtodo 10y agoIts the little things in life sometimes.
- garrettgrimsley 10y agoIf I wanted reddit-quality comments I would go to reddit. It's actually the second highest comment over there, rather than the first.
- deleted 10y ago[deleted]
- jrockway 10y agoBitching about comment quality is something that even Reddit has gotten over.
- garrettgrimsley 10y agoThere's no point to doing it there, it wouldn't change anything. And this thread is so bad that I expect it to be detached.
- NTripleOne 10y agoCareful not to detach your own head while getting so up in arms over something completely meaningless.
- saiya-jin 10y agowell mister your post quality is far below the one you complain about... ain't it a bit weird?
- WallWextra 10y agoHow long can this stuff last on your roof? Will it shed glass microbeads everywhere when the UV degrades it?
- deleted 10y ago[deleted]
- Baeocystin 10y agoProbably. A cursory google search shows that TPX is prone to thermal degradation. But glass microbeads do not have the same negative environmental impact as plastic ones. They are already naturally omnipresent in the biosphere.
- vanderZwan 10y agoWouldn't the latter effectively be equivalent to sand?
- Baeocystin 10y agoEssentially, yes.
- asafira 10y agoI fell in love with this idea when it first came out! Here is the first demonstration of it a couple of years ago: http://www.nature.com/nature/journal/v515/n7528/abs/nature13883.html http://www.nature.com/nature/journal/v515/n7528/abs/nature13...
- ChuckMcM 10y agoWow, that is an awesome result. With a cooling panels on the shade side of the roof and water pipes behind your PV panels on the sun side you can boost solar PV production by 3 - 5%. PV panels become less efficient when they are hot, we put some drip irrigation drippers on roof behind our panels (the panels are about 4" above the roof surface) and the evaporating water improved production by 2% on otherwise hot days.
- ainiriand 10y agoHow is this better than covering a surface with tinfoil which leaves infrared heat out?
- wscott 10y agoGo read the other comments. This is not an insulator. It will take a source of heat and start radiating that heat at a certain frequency where our atmosphere happens to be transparent. And because our atmosphere is transparent, there isn't at heat at that frequency outside so this "window" in your house is effectively one way. Also, the demonstrated energy transfer density of this stuff is high enough that the area of your roof is enough cooling to make a series dent in your cooling cost.
- ChrisFoster 10y agoWow, this is such a beautiful example of basic science turning into powerful technology. Technology which looks like it will be both cheaper and better for the environment than any current alternative. Does anyone have an idea of how long this might take to get to market as a rooftop heat exchanger for domestic use? I guess it largely depends on durability of the film; presumably the heat exchanger part of the system is a known quantity.
- deleted 10y ago[deleted]
- jsilence 10y agoDoes light in other wavelengths pass through with little transmission losses? Then it might be an elegant way to cool green houses in the summer. Yes, they can simply be vented, but it makes sense to keep them closed in order to keep CO2 fertilization inside and bugs outside.
- ph0rque 10y agoMy favorite method for cooling (and heating) greenhouses is ground to air heat transfer (GAHT): http://www.ceresgs.com/climate-control/gaht/ http://www.ceresgs.com/climate-control/gaht/ Note: this is similar to, but not the same, as geothermal heating.
- jsilence 10y agoYes! I would love to have a research greenhouse fitted with this tech. Thumbs up!
- jbmorgado 10y agoWell, at first sight this seemed really nice. But then, after thinking a bit about it (in my semi frozen office because someone turned out the heating during the night), won't this increase the heating costs a lot during the winter?