Professors Claim Passive Cooling Breakthrough Via Plastic Film (sciencemag.org)

What if you could cool buildings without using electricity? charlesj68 brings word of "the development of a plastic film by two professors at the University of Colorado in Boulder that provides a passive cooling effect." The film contains embedded glass beads that absorb and emit infrared in a wavelength that is not blocked by the atmosphere. Combining this with half-silvering to keep the sun from being the source of infrared absorption on the part of the beads, and you have a way of pumping heat at a claimed rate of 93 watts per square meter.
The film is cheap to produce -- about 50 cents per square meter -- and could create indoor temperatures of 68 degrees when it's 98.6 outside. "All the work is done by the huge temperature difference, about 290C, between the surface of the Earth and that of outer space," reports The Economist.

Comments

Cool

[Anonymous Coward]

Literally

Re: Cool

[stinkyjak]

They will be cold and dead... soon.

Re: Cool

[Anonymous Coward]

As below, it's heat transfer, which can quite easily result in a substantial temperature difference across a boundary. "Bullshit"? How? Got some research you're worried about? Or just generally angry about misc. stuff?

Re:Cool

[Mikkeles]

FTFS: It's not the plastic film that's important, it's the glass beads. Could these just be embedded in ordinary glass windows or some other transparent medium?

Re: Cool

[thinkwaitfast]

I'm going to combine this with a peltier cooler and make free energy.

All bow ad hail me

Re: Cool

[Applehu Akbar]

Not so much. In fact, it is a bullshit lie. It is not providing cooling, as is claimed. It is preventing heat transfer. There is no cooling involved and this is bullshit.

How did you get a thermodynamics lab to fit under that bridge?

Re:Cool

[budgenator]

No you couldn't embed them in glass, because the glass beads work by being resonate at a frequency that atmosphere is transparent to. The beads aren’t normal glass, they are transparent infra-red, most glass is rather opaque in infra-red. what you could do is apply it like a window tint, but I suspect it would have a lot of distortion and possibly an opalescent effect.

The film unsilvered is highly transparent to visible light, so the ideal application, would be to apply it to PV solar cells to help cool them and prolong their live span.

Re:Cool

[syntotic]

It is because mylar. I use mylar a lot so the idea must be in the air. You do feel an effect when wrapped in mylar that is not precisely heat, and it does insulate even if not spread flat against the light, though then it is better. So yes, it was a matter of pumping extra heat from underneath it out to make the cooling effect, but you do have to go into chemistry experimentation for that. This material means I can wear my heavy urban immersion suit and wrapped in mylarish material in the middle of hot Summer, and not die drown in my own sweat at over 42 C degrees inside.

You amerikan infidel

[fubarrr]

How much degrees in SI units?

Re:You amerikan infidel

[darthsilun]

LMGTFY: 36C

Re:You amerikan infidel

[swimboy]

You non-RTFA infidel! The article states the temperatures as 20C and 37C respectively.

Re:You amerikan infidel

[Lordpidey]

Yeah, but how many is that in Kelvin?

Re:You amerikan infidel

[darthsilun]

I think I'll let you google that for yourself.

Re:You amerikan infidel

[DontBeAMoran]

Forget your Kelvin, nobody uses that except in research.

What we need to know is how much degrees is it in football fields?

Re:You amerikan infidel

[Anonymous Coward]

Only heathens read the article.

Re:You amerikan infidel

[link-error]

But, can it cool a Beowulf Cluster?

Re: You amerikan infidel

[Anonymous Coward]

Really. That would be cool case material?

Re:You amerikan infidel

[wagnerrp]

Everyone uses it, every time you have to do more with the temperature than simply knowing what it is.

Re:You amerikan infidel

[thinkwaitfast]

Who uses Celsius in science? I though we were all science people here.

Re:You amerikan infidel

[Palmateer]

Is that NFL or CFL? Or prehaps european football?

Too good to be true.

[amiga3D]

This seems to be an incredible invention that will be a game changer. Passive cooling on the order of what this article talks about would seem to be too good to be true. If it is true these guys should be filthy rich soon.

Re:Too good to be true.

[Anonymous Coward]

AND a probable short-cut to save us some years on the global warming front

Re:Too good to be true.

[nospam007]

"Passive cooling on the order of what this article talks about would seem to be too good to be true. If it is true these guys should be filthy rich soon."

Don't forget to sell your Air Conditioning stock.

Re: Too good to be true.

[fubarrr]

Not as hardcore as an active cooling by a gas dynamic laser.

Most notable about this material is that it does not do heat pumping, just tricks with reflectivity and selective absorbtion, and emission bands

Re:Too good to be true.

[Anonymous Coward]

The concept is so simple it's gorgeous. Change the frequency of heat so it passes through the atmosphere freely and out into space. (At least that's what I understood it to mean, but I know very little physics) Sounds pretty legit to this layman...

Re:Too good to be true.

[Mr D from 63]

"Passive cooling on the order of what this article talks about would seem to be too good to be true. If it is true these guys should be filthy rich soon."

Don't forget to sell your Air Conditioning stock.

Its interesting that they have made the film, yet have not demonstrated it in a practical application. That makes me skeptical as they are relying on performance claims when they shouldn't have to. Why could they not take the film and cover a small structure (like a shed), and simply tell us the resulting cooling effect? And maybe compare against a simple reflective coating

Re:Too good to be true.

[Kjella]

This seems to be an incredible invention that will be a game changer. Passive cooling on the order of what this article talks about would seem to be too good to be true. If it is true these guys should be filthy rich soon.

Well the article certainly lacks critical sense:

And because it can be made cheaply at high volumes, it could be used to passively cool buildings and electronics such as solar cells, which work more efficiently at lower temperatures.

Cool solar cells.... by blocking the sunlight *facepalm*. Also I'm thinking how big a deal is the "not blocked by the atmosphere" really, I mean it's not like heat reflected of a little building significantly changes the ambient temperature. And finally production cost is one thing, but how it works in real dust-covered conditions and if it can survive being exposed to the weather all year long is another matter. I don't think it's quite as revolutionary as the article might suggest.

Re:Too good to be true.

[DamonHD]

It's called physics, even if you don't find it interesting.

1) Letting visible light through in principle lets the PV work while keeping it cool. The increase in output with lower temperatures is quite significant, thus the presence on the market of combined PV/Thermal panels for example. (And absorbing more of the visible light and removing the energy as electricity rather than letting it turn into heat would be good too, natch, and that one is being worked on.)

2) Outer space is at ~3K/-270C: having that as your cold sink *day and night* is really quite significant. What I cannot work out is if clouds are transparent at the same wavelengths, eg if this could be used to make the cold end of a Seebeck device even under cloudy skies: that would allow a small amount of power generation day and night also, if so.

This looks plausible to me and and an astonishingly good thing if it works even a 1/10th as well as the researchers hope.

Sometimes the science is good before the marketing people get to it.

Rgds

Damon

Re:Too good to be true.

[Waffle Iron]

I wouldn't sell it just yet. Even if this film works, it's probably only in clear conditions when the IR radiation can escape to outer space. On muggy cloudy or hazy days, I doubt it would work. On top of that, it would do nothing to lower the humidity in the building.

Re:Too good to be true.

[AJWM]

True, but these guys are in Colorado. We get maybe a dozen cloudy or hazy days a year. And it's a semi-desert, no muggy days.

Yeah, it might not work so well in the Mississippi valley region.

OTOH, if they're shifting to a frequency of infrared not absorbed by H2O, it might not care about puny water vapour.

Re:Too good to be true.

[modmans2ndcoming]

Wow, try reading....

"At the same time, the film sucked heat out of whatever surface it was sitting on and radiated that energy at a mid-IR frequency of 10 micrometers. Because few air molecules absorb IR at that frequency, the radiation drifts into empty space without warming the air or the surrounding materials, causing the objects below to cool by as much as 10C. "

Re:Too good to be true.

[Anonymous Coward]

Cool solar cells.... by blocking the sunlight *facepalm*.

PV solar cells are only responsive to certain spectra. If you don't block those frequencies, then you are good.
BTW, it is all those other frequencies that cause the solar cells to heat up - the energy of the frequencies they do process are not converted to heat, they are converted to electricity.

Re:Too good to be true.

[lgw]

Outer space is at ~3K/-270C: having that as your cold sink *day and night* is really quite significant.

Radiative cooling doesn't work that way: all that matters is your temperature. You don't radiate more into a cold area than a hot (a hot area sends more thermal radiation to warm you up, but that's orthogonal). It would be different if the atmosphere reflected IR, but that's not the case.

Re:Too good to be true.

[ChrisMaple]

Beware the glaciers.

Re:Too good to be true.

[Anonymous Coward]

2) Outer space is at ~3K/-270C: having that as your cold sink *day and night* is really quite significant.

Who said anything about Outer Space!

See! We just build another material that absorbs the same radiation that this one emits, then we just put them together and BAM. The first one gets colder, the other one gets hotter, with no work done!! Thermodynamics BTFO!!!!

Re:Too good to be true.

[rmdingler]

It's really innovative first generation tech. That's all.

TFS estimates this will remove 93 watts per square meter.

On average, the solar energy hitting the earth is 164 watts per sq. meter. An 8 hour summer day at 40 degree latitude can be as high as 600 Watts per sq. meter.

There will still be some air conditioning needs in the places they are presently very popular.

Re:Too good to be true.

[demonlapin]

It's a neat idea, but what happens in the winter? Seems like a good idea for the tropics, but otherwise not terribly useful.

Re:Too good to be true.

[religionofpeas]

On muggy cloudy or hazy days, I doubt it would work

Even if the cloud absorbs the IR, it's already out of the building you want to cool, so it has already served its purpose.

Re:Too good to be true.

[skids]

It would be different if the atmosphere reflected IR, but that's not the case.

Not in the sense of a mirror, but yes, it does, nondirectionally. More importanty, it tends to radiate at frequencies not absorbed by the material.

Re:Too good to be true.

[oddaddresstrap]

The problem being? It makes sense if you forgive a frequency given in units of wavelength.

Re: Too good to be true.

[Anonymous Coward]

Go buy carbon credits. Al gore owns the companies. Very interesting eh? He comes up with a problem and ohhh wow , a way to make billions.

Re: Too good to be true.

[Anonymous Coward]

You are forgetting the gravitons and graviolies. They project the ir waves frequency far enough - 10 kilonewtons

Re:Too good to be true.

[Anonymous Coward]

Uhh... no? A perfect vacuum is a perfect insulator against conductive transfer of heat, I'll grant you that, but this is radiative cooling. The vacuum of space is a black body at ~3 K with a heat capacity that's the next best thing to infinite.

Re:Too good to be true.

[wagnerrp]

I guess you've watched too many movies with stuff magically freezing in outer space. Objects in space are actually very slow to lose heat because vacuum doesn't conduct heat.

Objects in space are very quick to lose heat, when initially exposed to the vacuum, due to all the evaporation.

Re:Too good to be true.

[skids]

in order to sink heat you must have something to heat, and vacuum just ain't that.

If you can get heat into radiative form (which this gadget can) and it doesn't get reflected back at you, effectively, it is sunk.

Second - I don't suppose there is some kind of magic involved in this discover, that magically allows IR radiation to bypass the several kilometers of atmosphere you have before outer space.

It's called an absorption spectrum. In this case, specifically it's called the Infrared Atmospheric Window.

Re:Too good to be true.

[Anonymous Coward]

The film is nearly transparent to visible light. As long as your solar panels are designed for light in the visible spectrum (most are), then this would let it through and you'd still generate power. The waste heat produced by your solar cells would transfer to the film by conduction, and then the film would radiate it back into space (well, half into space, half back at the solar panel, but then it just conducts back and tries again).

This kind of material isn't new, in fact I'm quite confident I've seen a similar idea (in the form of a white paint that emits in the IR) on /. before, but the novelty here is that the plastic film is transparent to visible light and cheap to manufacture.

Re:Too good to be true.

[Anubis IV]

Cool solar cells.... by blocking the sunlight *facepalm*.

No. It seems you missed the part in the article where they said you'd first need to remove the mirror backing in order to use it with solar cells. I.e. It would let (nearly) all of the light through while still providing the heat dissipation properties.

Also I'm thinking how big a deal is the "not blocked by the atmosphere" really, I mean it's not like heat reflected of a little building significantly changes the ambient temperature.

I take it you're unaware of urban heat islands?

Controlling how light and heat get reflected from buildings is of growing importance to architects and engineers. Unfortunately, buildings melting cars is a thing that has happened, and urban heat islands are a contributing factor to global warming. Plus, if you can reduce the ambient temperature by pushing the energy out into space, you've effectively reduced your cooling needs, which is a double win.

Re:Too good to be true.

[skids]

Yeah, winter homes will have to wait until they can make the film thermally sensitive so it only works in the summer. Or change windows seasonally. Maybe an installable storm window that reflects 10um back in. But really anything that is a chore is likely to not get done.

(Currently there are different energy efficient glasses for northern versus southern U.S. homes, but it is harder to get the high-solar-gain/low-e type for north-facing windows in prefab windows for us northerners)

Re:Too good to be true.

[Waffle Iron]

That may be true for *air*, but if you look up the absorption spectrum for liquid water and ice (as found in clouds), it blocks 10um wavelength very well.

Re:Too good to be true.

[Anonymous Coward]

This seems to be an incredible invention that will be a game changer. Passive cooling on the order of what this article talks about would seem to be too good to be true.

I thought so too.
Can we finally have quiet 3D graphics cards? Most of their bulk comes from the heatsink + fan structures
While we're at it, PC towers, refrigerator motors and air conditioners are more important candidates. When you live in a noisy city like New York, you only truly realize just how noisy things are at night as all that is gone (nothing quite kills the low-battery notification beeps that often plague neighboring apartments for the mandatory smoke alarms)

Re:Too good to be true.

[Waffle Iron]

The effect depends on the fact that outer space doesn't radiate much at those frequencies.

Under clouds there is more of a thermal equilibrium. So there will be about as much IR energy in that band being emitted from clouds and entering the building as leaving it. It's the same reason that cloudy nights usually stay warmer than clear nights.

Re:Too good to be true.

[Anonymous Coward]

Ooops. Forgot a bit of crucial text while editing my parent post:

When you live in a noisy city like New York, you only truly realize just how noisy things are at night as all that is gone DURING A BLACKOUT (nothing quite kills the low-battery notification beeps that often plague neighboring apartments for the mandatory smoke alarms)

Re:Too good to be true.

[Rei]

It doesn't work like that. Radiative heating/cooling works via exchange of IR. You're not just giving it up; everything you're radiating at is proportionally radiating back at you. So you cool the most when you're radiatively exchanging with something that's very cold. Aka, you want to be radiatively exchanging with the cosmic microwave background, not with low-altitude clouds. That's the whole point of radiating at low absorption frequencies in the atmosphere: so that you're exchanging with space, not with atmospheric air.

Re:Too good to be true.

[Anonymous Coward]

It's actually huge. In theory, thermal energy from the sun is a nice black-body curve. However, the atmosphere is both reflective and absorptive. In theory, all material have "an" emissivity, but in some materials it's very frequency sensitive. For example, chrome plated seat belt buckles get stupid hot because, though they're reflective (low emissivity) in the optical, they're very absorptive in the IR.

It's completely plausible that they've found a material that has a high emissivity in the low IR near ambient, and highly reflective in the high IR, where the solar emissions are. Further, the important part of "where the atmosphere is transparent" is to send emit the energy in a band where it will travel out to space, not where it will reflect back, or be emitted by the energy in the atmosphere.

Re:Too good to be true.

[Anonymous Coward]

You're just dead wrong. You are surrounded by black body radiators, and you will absorb energy from the. The temperature of them most certainly matters.

Re:Too good to be true.

[thinkwaitfast]

Cooling the backs of solar panels works also. I've though about running water lines on the back of mine, but the cost relative to buying new panels, as low as 11c/watt, isn't worth it. Cheaper to buy more panels and screw the efficiency.

Re:Too good to be true.

[thinkwaitfast]

~ -0.44%/degC

Re:Too good to be true.

[Anonymous Coward]

> If it is true these guys should be filthy rich soon.

They're at University of Colorado. All your patent are belong to us!

Re: Too good to be true.

[Anonymous Coward]

Mmmmmm.... gravioli!

Re:Too good to be true.

[Anonymous Coward]

Did you calculated in the free water-heating for your domestic needs?

Re:Too good to be true.

[minstrelmike]

Actually, if all the indoor temperatures cool down, then that means the outdoor temperatures must increase. It's not like we're getting rid of any incoming solar radiation. So this kind of heat pump would make the outdoor temperature higher which means it increases the warming that affects glaciers. The only way a film like this would do any good is if we draped it completely over Antarctica and Greeneland to keep them from melting. Then the Earth could warm up but we wouldn't have to worry about sea levels rising.

Win-win right?

Re:Too good to be true.

[Darinbob]

University professors. Meaning they do it for science, and grant money, not to get filthy rich. The concept is out there but the next step is to make it feasible and affordable.

Re:Too good to be true.

[Anonymous Coward]

There *is* a strong smell of TGTBT here. But the principle is interesting - instead of reradiating heat as normal infrared, which is trapped by the atmosphere, reradiate at a wavelength at which the atmosphere is transparent. If it really does work, it has possibilities. Also some drawbacks if it works too well.

For instance, solar cells work better if not really hot. So a cooling layer over them with this stuff would be helpful in reducing temps in warm weather. But do they work well when hard-frozen? How far below zero C would this take the cells in otherwise freezing weather? IOW this might be useful for cooling solar cells in the summer in a hot climate, but might not be beneficial in the winter.

Re:Too good to be true.

[Anonymous Coward]

Actually in the sense the GP means it he is correct - if there is a frequency window in which you can lose entropy then you need a sink to gain it. If your sink (outer space) has a higher temperature, then you’ll get heated by the radiation in the other direction.

Re: Too good to be true.

[Anonymous Coward]

It did say in TFS that it emits radiation on a wavelength that isn't absorbed by the atmosphere, meaning the heat would transfer directly to space. Even if it didn't, the problem isn't the heat generated by your air conditioner. It's the co2 emitted by the coal plant that powers your air conditioner.

Re:Too good to be true.

[Anonymous Coward]

RTFA (or even just the summary!) and you will see that you are 100% wrong. They say they radiate the heat back to space.

Re:Too good to be true.

[lgw]

Not in the sense of a mirror, but yes, it does, nondirectionally. More importanty, it tends to radiate at frequencies not absorbed by the material.

Look, "reflection" is a specific concept, OK? It's a different thing than absorption and emission. They are two different effects, which is why we use different words to describe them. There is some refraction by clouds, and I'm sure some trivial percentage is refracted multiple times to end up headed back towards the surface, but that's about it.

Why does the distinction matter? Actual reflection of IR nearly blocks radiative cooling (at some point the reflective surface, not being perfect, heats up and starts radiating). This is why a really good thermos needs a reflective layer in addition to a vacuum gap. If IR were being reflected close to the emitter, which it's not, changing the frequency to one not reflected would make a huge difference.

Absorption is very different. Sure, the atmosphere absorbs IR and becomes warmer as a result, but it's not like that happens meaningfully within a few yards of the ground! Changing the frequency of your thermal radiation a bit will not make a meaningful difference in cooling. OTOH, covering something sitting in the sun with a reflective surface makes a significant difference.

Re:Too good to be true.

[Anonymous Coward]

a hot area sends more thermal radiation to warm you up, but that's orthogonal

Well ... it's still reasonable to think about it as if the two were entangled. Your net radiation into some area (i.e. the amount you radiate into it, minus the amount it radiates into you) is proportional to the difference in the fourth powers of the temperatures of you and that area.

Saying that space is at 3K is misleading, though. If you're in orbit on the night side of Earth, half your sky is empty space at 3K - and the other half is the Earth at ~300K. The effective temperature is determined by the mean of the fourth powers of these numbers: (0.5 * 3^4 + 0.5 * 300^4)^(1/4) = 250K, which isn't nearly as cold as 3K.

Round the day side, it's even worse: half your sky is still the Earth at ~300K, and a tiny fraction is the Sun at ~5000K - which, due to that fourth power, has a much greater effect than you'd expect.

Re: Too good to be true.

[Anonymous Coward]

It could significantly reduce the power needed for air conditioning though, no small deal there.

Re:Too good to be true.

[Anonymous Coward]

The other body radiates heat BACK at you. So yes, relative temperate difference totally matters. For example in LEO the earth is a significant source of heat even on the shadow side.

Re: Too good to be true.

[slazzy]

That could be very useful in much of the world, turn some radiation into electricity, block the rest to lower ac costs.

Re:Too good to be true.

[Anonymous Coward]

Outer space is at ~3K/-270C: having that as your cold sink *day and night* is really quite significant

The funny thing about windows is they don't typically point at space. This might be reasonable for individual homes in rural settings (assuming it doesn't light the surroundings on fire by elevating the temp 30 degrees or so on an already hot and dry day,) but it is much more likely to be applied by some "environmentalist" with a skyscrapper in a city, which will simply drive up the cost of cooling for his neighbors, until they all race to install it and are ultimately back at square one.

Re:Too good to be true.

[Ungrounded Lightning]

It's a neat idea, but what happens in the winter?

Put a cover over it.

Glass is good. It is pretty much opaque to far infrared. Instead of seeing the cosmic background temperature of a few degrees kelvin, it will see the temperature of the glass - which is about the same as its own temperature. So the radiative heat flow will be just about zero.

But ANYTHING opaque to infrared will do the same.

Another approach: Instead of coating the house, coat a radiative cooler to make chill water, and pump that through a heat exchanger in your forced air heating/air conditioning system. Don't want cooling? Don't pump the water. (Adjust how much you pump it to regulate your temperature.)

That's not "no power", but pumping chill water is very little power, and you need to circulate the air anyhow. Most of the energy cost of air conditioning is refrigeration, and you still get that for free.

Re:Too good to be true.

[skids]

Changing the frequency of your thermal radiation a bit will not make a meaningful difference in cooling.

It is a bit backwards to phrase this as "beaming heat into cold space" rather than "reflecting most incoming ambiently-produced IR radiation while selectively emitting radiation in a same band we absorb" This doesn't seem to be the fault of journalists, it's phrased that way in the paper. This article avoids using that semantic.

Were they to allow the wavelengths re-emitted by the general environment outside, you'd get an offsetting absorptive heat gain. They could likely get the same effect at different wavelengths, but choosing this wavelength means basically no heat gain from atmospheric emission. There could even very well be a better choice of wavelength based on whatever materials the ground is made up of, but that could vary.

Re:Too good to be true.

[Anonymous Coward]

Well, you talk about science, but you don't seem to be much knowledgeable in it, aside from your skill to lookup stuff in wikipedia.

That is ironic. Really, it is. Read some more of the other comments, made by people a lot more knowledgeable than you, to see why.

Re:Too good to be true.

[Insanity Defense]

So much for the Trump Carrier deal.

Re:Too good to be true.

[budgenator]

It's not like we're getting rid of any incoming solar radiation. So this kind of heat pump would make the outdoor temperature higher which means it increases the warming that affects glaciers.

1. Glaciers don't melt much because of increased air temperatures, air just doesn't have enough heat to melt much ice.
2. This isn't a "heat pump", it's a radiator, it radiates infrared light at a wavelength the atmosphere doesn't absorb so the heat energy can go directly to outer space.
So yes we are actually "getting rid of any incoming solar radiation."

Re:Too good to be true.

[budgenator]

>Its interesting that they have made the film, yet have not demonstrated it in a practical application. That makes me skeptical as they are relying on performance claims when they shouldn't have to. Why could they not take the film and cover a small structure (like a shed), and simply tell us the resulting cooling effect? And maybe compare against a simple reflective coating

They have a peer-reviewed article published in "Science", other Researcher's have published papers on the same effect using difference materials and the "The Economist" article shows the Researcher's holding a big-ass roll of the stuff, there isn't much to be sceptical of.

Re:Too good to be true.

[Anonymous Coward]

if this work as like you guys are saying then global warming problem is solved

Re:Too good to be true.

[Anonymous Coward]

Objects in space are very quick to lose heat, when initially exposed to the vacuum, due to all the evaporation.

Reminds me of an argument I had with a roommate in college, over whether it would "feel cold" if you stuck your arm into a vacuum chamber.

Strangely, I can't recall which way I argued!

Re: Too good to be true.

[Anonymous Coward]

I think you are even more stupid than you sound...

Re:Too good to be true.

[syntotic]

Reach Outer Space from the comfort of your sofa! Radiate at 10 micometers! Starts sounding like advertisement. Is it already in amazon or how long we have to wait for delivery?

Re:Too good to be true.

[Mr D from 63]

They have a peer-reviewed article published in "Science", other Researcher's have published papers on the same effect using difference materials and the "The Economist" article shows the Researcher's holding a big-ass roll of the stuff, there isn't much to be sceptical of.

How does holding a roll of it prove how effective it is in a practical application? I didn't say it didn't exist, in fact I said that since they have produced it why don't they demonstrate it in a practical application. The fact they have not when it would be so easy to do is why I am skeptical.

Re:Democracy Fail

[amiga3D]

You're the type person that should be shot in the head. Mao was a motherfucking mass murder in the same style as Stalin and Hitler. Fuck him in the eye socket and you too.

Re:Democracy Fail

[russotto]

DONALD J. TRUMP has announced a solution to the problem of global warming, in partnership with the University of Colarado at Boulder. Millions of acres of this cooling film are to be spread across the desert near the US-Mexican border, counteracting the heating effects of carbon dioxide. Anyone attempting to cross this film will be shot as a traitor to Planet Earth.

Re:Democracy Fail

[aliquis]

Your opinion is the fail when it comes to democracy.

That you want to be governed by an elite (or anyone) is irrelevant. I don't want to and shouldn't be forced too. Now go fuck off.

How interesting! (Cool was taken)

[rmdingler]

The heat is returned to the state in which it arrives, infrared radiation, and returned to space.

Neither the building materials, nor the air in close proximity to it, get the chance to absorb the radiation and the heat the absorption develops.

Re:How interesting! (Cool was taken)

[Anonymous Coward]

Coat the earth with this and we will have anthropomorphic global cooling...

Re: How interesting! (Cool was taken)

[Anonymous Coward]

Anthropogenic.

Re:How interesting! (Cool was taken)

[russotto]

The heat is returned to the state in which it arrives, infrared radiation, and returned to space.
Neither the building materials, nor the air in close proximity to it, get the chance to absorb the radiation and the heat the absorption develops.

A plain mirror could do that. The idea here is that infrared emitted by warm objects is absorbed and re-emitted at frequencies the atmosphere is transparent to, thus the heat escapes to space rather than warming the air.

Re:How interesting! (Cool was taken)

[ChrisMaple]

Cool gods.

Re:How interesting! (Cool was taken)

[rmdingler]

Depends on what the mirror was made of. Some would absorb the heat activated by infrared "excitement" of their molecules.

Re: How interesting! (Cool was taken)

[Nkwe]

Unless you are furry.

Also good for Solar Panels, but don't expect to

[Anonymous Coward]

see it ever!! Do you think the Special Interest people are going to let this one come to fruition?? Hell no!! They like things filthy, just like they are! The Web is packed with thousands of great inventions and solutions that you never will see. They get Squelched. Bought out, Buried and Patented. What? Do you think the air conditioning people are going to put up with this film? You're cutting into their territory.. Money wins - You lose! Did you get your biofuel from you local landfill yet? No?? Why not? All it takes to convert almost anything in a landfill into biofuel, is a high pressure tank, heat and time. Because they've been doing it for almost 2 decades now in Canada. (It's been mostly scrubbed off of the Web.) Latin people laugh at you when you don't believe they can make gasoline out of tires. ... Sorry about the rant, you intellectual people... I'm done ranting now about our backwards country.

Re:Also good for Solar Panels, but don't expect to

[lucm]

The Web is packed with thousands of great inventions and solutions that you never will see.

Wrong. The Web is packed with conspiracy theorists who don't understand why some "great inventions" are not practical. We've heard this bullshit for decades about electric cars and it took a billionaire with balls of steel and no fear of bankruptcy to make it happen. And yet they're barely making a profit nowadays after years of losing money to the tune of 1 billion per year.

Get real. There's no mysterious stash of brilliant inventions that got "scrubbed" from the web by nefarious agents. There's tons of unrealistic, not cost-effective ideas and only one Elon Musk, that's the real problem.

Re:Also good for Solar Panels, but don't expect to

[knorthern knight]

> Did you get your biofuel from you local landfill yet? No?? Why not? All it takes
> to convert almost anything in a landfill into biofuel, is a high pressure tank,
> heat and time. Because they've been doing it for almost 2 decades now
> in Canada. (It's been mostly scrubbed off of the Web.) Latin people laugh
> at you when you don't believe they can make gasoline out of tires. ...

Yes you can make biofuel. Yes it does work in Latin America, aka the tropics. Other areas of the planet have this thing called "winter". Biofuel congeals when temperatures drop near zero. Back in 2009 https://wattsupwiththat.com/20...

> "All schools in the Bloomington School District (Minnesota) will be closed today
> after state-required biodiesel fuel clogged in school buses Thursday morning and
> left dozens of students stranded in frigid weather, the district said late Thursday.
>
> Rick Kaufman, the district's spokesman, said elements in the biodiesel fuel that
> turn into a gel-like substance at temperatures below 10 degrees clogged
> about a dozen district buses Thursday morning. Some buses weren't able to
> operate at all and others experienced problems while picking up students, he said.
>
> We had students at bus stops longer than we think is acceptable, and
> that's too dangerous in these types of temperatures," Kaufman said."

Other school districts avoided these problems by either idling their buses all night long, or using heated parking garages. Not exactly "green solutions". And finally, the biodiesel stuff was forced down people's throats in Minnesota. If it's so cost effective and wonderful, why does it need to be mandatory? And the cold-weather problems are not exactly unkown. http://www.startribune.com/min... because "essential services" are exempt from the mandate.

> First, key industries have been permanently exempted from the requirement to use
> any biodiesel whatsoever. The state's nuclear power industry was given an indefinite
> exemption. A temporary exemption for railroads; taconite and copper mining;
> logging, and the U.S. Coast Guard was changed to a lifetime pass. Through
> such action, legislators acknowledged that biodiesel is not reliable enough
> to ensure that these vital industries would not suffer serious disruptions.

RTFA

[Anonymous Coward]

It's dissipating heat, but only in one direction. So the effect is heat transfer.

Re:its basically a sun shade that you can see thro

[frovingslosh]

Even I can see through this lie. It's really just Maxwell's daemon sorting molecules. Just another BS story on Slashdot that will get hype for a few days and then no product will ever come to market. An obvious clue that even the "inventors" know this is complete bullshit is the claim "All the work is done by the huge temperature difference, about 290C, between the surface of the Earth and that of outer space,". Is anyone buying that crap? 'cause if you don't then it is pretty obvious this can't work.

Re:its basically a sun shade that you can see thro

[russotto]

Is anyone buying that crap? 'cause if you don't then it is pretty obvious this can't work.

Unfortunately you're probably right that it's too good to be true, but using the temperature difference between space and earth is not impossible. It's why deserts get cold a night.

Re:Democracy Fail

[Anonymous Coward]

Fuck you.

Re:its basically a sun shade that you can see thro

[Anonymous Coward]

"All the work is done by the huge temperature difference, about 290C, between the surface of the Earth and that of outer space,". Is anyone buying that crap?

Radiative cooling is a very real effect. It's why telescope mirrors often dew up even when the ambient temperature is above the dew point, and why your car windshield will sometimes have condensation on it while the side windows/mirrors don't.

Re:its basically a sun shade that you can see thro

[Anonymous Coward]

So any material that is transparent in one wavelength and opaque in others is Maxwell's demon?

Or is it that any material that emits photons at a certain wavelength is Maxwell's demon?

Because both of those are well known, and these guys have just ingeniously combined the two effects to create an awesome new type of Stirling engine that connects the ground with space. Cooling is just one application. It should be fairly simple to generate power with this as well.

Come on, it's just a goof

[Anonymous Coward]

You had to know when you read the two guys were named Yin and Yang.

Re:Come on, it's just a goof

[frovingslosh]

That's lacist!

Re:its basically a sun shade that you can see thro

[DamonHD]

It's called physics.

Outer space is on average at about 3K/-270C. So if you can freely radiate energy away to it from a surface then that surface can nominally get to, or close to, that temperature. Having that that as the cold end of a Carnot heat engine, such as a thermal electricity generation plant, would do amazing things for efficiency in principle. Never mind aircon and PV.

So it's not crap.

And you can experience a similar effect in the opposite direction standing some distance from a bonfire on a cold night: you can feel the heat on your face even while the air around you is a very different temperature to your skin and the bonfire.

Rgds

Damon

On a sunny daymirror, a mirror

[Anonymous Coward]

reflects sunlight at about 93 watts per square meter.

title

[Anonymous Coward]

I hate this phone

Yeah, but WHEN?

[JustAnotherOldGuy]

Yeah, but WHEN? When will we see this available for consumer use?

I see news stories every damn day about some amazing breakthrough in this field or that field, but fuck all if it ever seems to make it to market.

I must have seen 100 stories in the last few years about more efficient and less expensive solar cells, but where the fuck are they?

The same with medications and advances in medical technology....lots of news and hype and excitement but rarely does anything ever appear.

FFS, all I want is to be buried in a casket made of an advanced polymer plastic film that eliminates diabetes and has a 98% solar conversion efficiency rate, and that can autonomously pilot itself down I-5 during rush hour. Is that too fucking much to ask?? Oh, and the battery has to last for a full week without a charge.

Re:Yeah, but WHEN?

[Anonymous Coward]

All these 'advances' are a scam. Remember how computers were going to get more powerful, how we'd have literally megabytes of storage available? And they'd get smaller so we wouldn't have to lug around a briefcase+ size device like one day they'd be phone size? What happened to any of that? Don't get me started on the stories of how one day we'd be able to engineer genes directly. It's all pie in the sky. And like you say, medical research, all those stories about keyhole surgery and designer drugs. Never gonna happen.

Re:Yeah, but WHEN?

[ChrisMaple]

Pay attention. Solar cell prices have dropped dramatically over the last decade. Nobody has claimed the really efficient stuff (>40%) is cheap.

Medical technology is reaching the public, despite the FDA's foot dragging. For example, the advances in available AIDS treatment has made a lot of news in recent years.

Re:Yeah, but WHEN?

[CanadianRealist]

I think maybe you're on the wrong website, you don't seem to be interested in new discoveries. You might be happier with a site which concentrates on something like "new products coming out this year."

Many of us enjoy reading about new discoveries, knowing that not every promising new discovery will lead instantly to a mass marketed product. (If it ever does.) Every time there's a story about research on improving solar panels or battery efficiency there's always people complaining that they never see these things coming to market, ignoring the steady improvements that we see in both over time. For every story about improving ranges of electric vehicles there's someone who says it's useless because it doesn't meet their use case.

If you really are an old guy think about all the progress you've seen in your lifetime. It didn't happen all at once, but we've sure come a long way. My first computer had 48 kb of ram, 5 1/4" floppies as the only storage, and I used a Model 33 Teletype as a printer. It was a home built Southwest 6800, for those old enough to know what that was.

Re:Yeah, but WHEN?

[DamonHD]

This is a VERY boring trope. If you only want completely finished consumer grade tech then stop reading /. and go read a product catalogue, maybe on paper, and stop wasting our time on your public masturbation/trolling.

For example, on another topic:

https://slashdot.org/comments....

And yes those more efficient PV cells are emerging in several different directions depending on application, and I'm been installing some of them. In terms of W/$ (thus J/$) I've recently put up stuff that cost me 1/10th of what went on my roof a few short years ago.

So if you would bother using your favourite search engine or paying attention to the field rather than whining, you'd know about them. The improvement in PV has been a science and engineering wonder possibly only eclipsed by CPU performance.

And here is probably the best-known pretty chart from NREL, easily found with a search for (wait for it)... "chart of solar PV efficiency":

https://www.nrel.gov/pv/assets...

Damon

Re:Yeah, but WHEN?

[JustAnotherOldGuy]

I'm sorry that you, like some of the other responders, are so humor impaired. Perhaps a girlfriend or a hobby would be helpful, or maybe even moving to an above-ground location. :)

Re:Yeah, but WHEN?

[JustAnotherOldGuy]

Epic humor-impairment detected, resetting all expectation levels....done. Press any key to continue.

Re:Yeah, but WHEN?

[DamonHD]

If you deliberately invoke a very tiresome trope then you are being a troll. A low-grade version of shouting FIRE in a crowded space. Please don't.

My solar PV wouldn't work very well underground, and my g/f and kids do need to be above ground also for things like shopping and school.

Damon

Re:Yeah, but WHEN?

[JustAnotherOldGuy]

If you really are an old guy

If?? I'll have you know that my original birth certificate came on a clay tablet.

And we didn't have "computers", we had to throw rocks into baskets and calculate the outcomes through probability statistics. Not only that I had to walk 25 miles to school on my knees over broken glass every day, and it was uphill both ways! And this was before schools even existed! One time our dinosaur broke down and we all starved to death!

I'm so old I don't even buy green bananas, and I only read Playboy for the articles! Why, I'm so old that when I order a three-minute egg they ask for the money up front! When I was a boy the Dead Sea was only sick!

Re:Yeah, but WHEN?

[JustAnotherOldGuy]

My solar PV wouldn't work very well underground, and my g/f and kids do need to be above ground also for things like shopping and school.

I commend you on your detailed fantasy life.

Re:Yeah, but WHEN?

[whoever57]

Nobody has claimed the really efficient stuff (>40%) is cheap.

When your input energy is free, efficiency isn't a primary concern. Efficiency of solar panels only affects the overall size of the array for a given output power rating. Roof space is free, so who cares about efficiency, except for some niche applications?

Re:Yeah, but WHEN?

[amiga3D]

The only thing keeping me on the grid is the price of batteries and the other associated electronics needed for a home system. The panels are the cheapest part of the system.

Re:Yeah, but WHEN?

[amiga3D]

We threw bones and had this guy with bones sticking through his nose and ears and lots of freaky tattoos and piercings that read them. Not much different from today now that I think about it.

Re:Yeah, but WHEN?

[lucm]

Remember how computers were going to get more powerful, how we'd have literally megabytes of storage available?

The problems scale faster than the solutions. For instance, I have a 32GB SD card on my phone, but guess what, that can only store 5 or 6 HD movies, and will probably be barely enough for the trailer of a 4k movie. By the time storage catches up, I will still only be able to store 5 or 6 movies in a 5-year old format and 0.1 movie in the newest format on a phone. Progress much.

Re:Yeah, but WHEN?

[religionofpeas]

Roof space may be free, but it's not unlimited.

Re:Yeah, but WHEN?

[DamonHD]

You said elsewhere, amongst some insightful posts:

Slashdot used to be more of a "reasoned discussion" kind of place, but it's really gone to hell in the last 5 to 10 years. Sadly I think much of the internet has descended into hair-trigger flamewar territory, not just Slashdot. :(

Well, maybe you could avoid starting some of the fires here. Please. Life is too short.

Damon

Re:Yeah, but WHEN?

[thinkwaitfast]

I got an advertisement in the mail this week for solar panels at 11c/watt. They're grade C, but I'm sure most would last the 6 month it will take to break even.

Re:Yeah, but WHEN?

[tepples]

But with how (physically) small a phone's screen is, what's the point of more than 480p or so if you're viewing it on a phone? Or are you using a full-size TV as the phone's monitor?

Re:Yeah, but WHEN?

[nasch]

I'm sorry that you, like some of the other responders, are so humor impaired.

It's very difficult to tell the difference on the internet between a joke and something an idiot says. It's almost impossible if the joke isn't funny (which yours wasn't). When you write a joke, take another look at it and think "is there any possible way a human might say this to either be serious or troll other people?" If so, then it probably isn't going to land as a joke.

Re:Yeah, but WHEN?

[Anonymous Coward]

Isn't it amazing how every technology claim ever made has come true?

Re: Yeah, but WHEN?

[Anonymous Coward]

Wtf are you downloading 4k movies for your phone? Even a 2+ hour 1080p h264 movie is far under 3GB. 720p often under 1GB.

You're also ignoring VP9 and the goal to reduce file sizes for streaming.

Re:Yeah, but WHEN?

[JustAnotherOldGuy]

It's very difficult to tell the difference on the internet between a joke and something an idiot says.

Really? Are you saying that you took this bit as serious commentary:

FFS, all I want is to be buried in a casket made of an advanced polymer plastic film that eliminates diabetes and has a 98% solar conversion efficiency rate, and that can autonomously pilot itself down I-5 during rush hour. Is that too fucking much to ask?? Oh, and the battery has to last for a full week without a charge.

So...you read that and took it as serious commentary and you saw nothing even slightly funny or silly about it? If so, then you're the idiot here, not me.

Re:Yeah, but WHEN?

[nasch]

No, didn't notice that part.

Re:Yeah, but WHEN?

[JustAnotherOldGuy]

No, didn't notice that part.

So, let's recap: I am not to blame for your lack of reading skills or your inability to finish a paragraph.

You're like the guy that walks through the front doors of the Louvre, doesn't immediately see the Mona Lisa, and concludes, "This place sucks!"

Re: Yeah, but WHEN?

[lucm]

Wtf are you downloading 4k movies for your phone?

I don't. I was just giving a reference because as it happens I had to move a big file from a location that had only wifi to a location that had only bluetooth.

Re:Yeah, but WHEN?

[Anonymous Coward]

You may want to get tested for autism spectrum disorders.

the radiator will be huge at 50w/m2 for anything.

[Anonymous Coward]

It cools at 50w/m2, if you put the material outside that will cause it be a bit cooler that ambient temp, to get to to be cooler it has to be behind layers of glass or something else that allow that IR range to pass, and that assembly would need to be on enough area to cool a house. My house has a 4 ton air conditioner, it can remove 14400watts/hr (less on hot days, let say 7200w/hr on a hot day), so to cool my house with this I need 144m2 of area that is contained under something that protects it from convection and conduction. So while the film is cheap, the assembly to utilize the film is gong to be quite large and expensive, and that assembly is going to have to point into space, so likely the roof is going to have to be nearly flat, and you are going to have to have some way to get the heat to the assembly. Even if you used this as a efficient radiator for a AC unit, 36-72m2 per ton is quite large and is going to be quite expensive to build that will survive common weather conditions.

Re:its basically a sun shade that you can see thro

[Anonymous Coward]

It's an interesting idea. I'm somewhat skeptical that this material can reflect the rays back into space no matter what angle the building surface is to the sun, but it stands to reason that if IR waves can heat a surface, reflecting all or most of them would result in less heat being transmitted to the surface.

It's probably real

[Anonymous Coward]

He's a real scientist at a real university (stanford) and heads a group that studies this stuff. There was a published article on similar materials/ideas published in part by him in Nature in 2014.

The article says nothing about what demonstrations have occurred.

I read the op article and from a stupid non-physicist point of view it sounded legit. If we can get heat from light, why can't we get light from heat? And that's all this seems to be.. a method of changing heat into light.

If you're an expert on physics, please make a post. I might ask my wife's friend, she's got a phd in materials engineering from umich, what her opinion is.

Re:Democracy Fail

[ChrisMaple]

Mao's political method was to enter a village and kill every leader who didn't agree with him. Get a new set of leaders, kill every leader who didn't agree with him. Repeat until purified.

The words "nuance and subtlety" do not apply. His central committee was thugs and murderers like himself.

Just WTF are people being taught these days?

Link to paper...it's actually better than 93W/m^2

[Anonymous Coward]

It is behind a paywall, but here is the paper - http://science.sciencemag.org/content/early/2017/02/08/science.aai7899

They actually show greater than 140W/m^2 of cooling at one point during a 72h test and claim the 93W/m^2 during noontime sun. I thought it was really interesting that they have actually made a roll of the material already (not just a small sample) and the material is relatively simple. They also mention that while this was made with polymethylpentene, it could likely be done with a little less emissivity with polyethylene or PMMA, both really cheap.

Heat

[kqc7011]

I would be more interested in this if it worked the other way, warming my house. Where I live, I need the furnace to run 9 months of the year. And 5 of those 9 months every day. Last year, I ran my AC on 8 days.

Re:Heat

[Anonymous Coward]

I would be more interested in this if it worked the other way, warming my house.
Where I live, I need the furnace to run 9 months of the year.
And 5 of those 9 months every day.
Last year, I ran my AC on 8 days.

Global warming will fix that soon enough.

Re:Heat

[currently_awake]

You can put an IR film on your windows to trap heat inside. You can use a heat pump to take heat from the ground and dump it in your house (most cheap units take from the cold air, but the ground has more heat).

Re:Heat

[Ken McE]

kqc7011:
"I would be more interested in this if it worked the other way, warming my house. "

No problem. Just flip it around backwards!

Re:Heat

[Anonymous Coward]

Your house has an AC?

Re:Heat

[Anonymous Coward]

You can put an IR film on your windows to trap heat inside

That's an interesting thought, but couldn't you just NOT put the film up and let the heat come in from the sun anyway, like it already does?

I'm not sure this film would actually help you heat anything.

Re:Heat

[Ungrounded Lightning]

I would be more interested in this if it worked the other way, warming my house.

There are lots of designs for doing that. Look at any renewable energy bulletin board (such as fieldlines.com).

Common thread is:
  - Black (or otherwise visible light absorbing) target.
  - In an insulated box.
  - With a glass window (that does NOT have an infrared reflective coating)
  - And some way of transferring the heat from the black target to the house air.

Glass is opaque to infrared and passes visible light. Sunlight goes through, is absorbed by the black material, and heats it (to the tune of about a kilowatt per square meter at noon). The material re-radiates, but it is far too cool to re-radiate in the visible spectrum. So it re-radiates in the infrared, which doesn't escape through the glass and is thus re-absorbed.

It's called "The Greenhouse Effect". B-)

In one of my favorite designs the black target is a series of tubes consisting of used aluminum drink cans with the tops and bottoms removed, painted black. They're very good at absorbing light, because it takes multiple bounces down the valley between the tubes, giving the paint many chances to absorb it. A 4" computer fan pumps air through the box to extract the heat.

But there are LOTS of other designs. Including houses with large south or south-east facing windows and overhanging roofs that shade them in the summer but not in the winter (to rough-tune the absorption). The floor, walls, furniture, etc. serve as the visible light absorber.

My ranch house works like that - a little too well. In the afternoon it will git to 90+ degrees when it's single-digit temperatures outside.

Like Rossi or Borealis & Coolchips scams

[Anonymous Coward]

Remember the scams pushed over a decade ago by Slashdot?
https://tech.slashdot.org/stor...
and
http://science-beta.slashdot.o...
Both are stock pump up junk science so a person or family can accept free money investments, so I am a bit concerned when Slashdot promises something amazing in free energy or heat transfer.
Borealis Wheeltug Coolchips scams https://en.wikipedia.org/wiki/...
Rossi Scams https://en.wikipedia.org/wiki/...

Re:its basically a sun shade that you can see thro

[Anonymous Coward]

This has nothing to do with reflections.

Re:the radiator will be huge at 50w/m2 for anythin

[ChrisMaple]

Part of your air conditioner's load is removing heat that has been conducted inwards through roof and walls. Coat your house with this stuff and the heat flow will be outwards. Perhaps it won't be enough to remove the heat coming through windows and air leaks, and generated internally, but it should lessen your AC load substantially..

Re: Democracy Fail

[Anonymous Coward]

If you favor Mao, you should try reading at least one book some time. At least one.
So glad Hillary and her commie supporters lost.

not another one

[Anonymous Coward]

Oh my gawd,another break through battery story..
Another one that will probably never make it to market..

WTH is this shit.

[Anonymous Coward]

98.6 outside, I guess we're on the dark side of Venus or something?

Re:WTH is this shit.

[skids]

Thermal inertia and the transfer of heat by winds in the lower atmosphere mean that the temperature of Venus's surface does not vary significantly between the night and day (https://en.wikipedia.org/wiki/Venus#Atmosphere_and_climate)

Re:the radiator will be huge at 50w/m2 for anythin

[radl33t]

your house is also a literally a pile of unengineered garbage. like most US homes, it was both designed and built by idiots. Maybe you should buy a better house with adequate air sealing, insulation, and a design that at least made a small attempt to minimize direct solar gains. Guess what, its even cheaper to build houses intelligently. But when you sell products to idiots, the quality doesn't matter and instead you get expensive 50kBtu/hr machine to cool it and piss away extra money to the utilities.

Re:Democracy Fail

[Anonymous Coward]

The ends always justify the means.

As long as you're the one who wins and gets to rewrite history, anyway.

Re:its basically a sun shade that you can see thro

[skids]

So any material that is transparent in one wavelength and opaque in others is Maxwell's demon?

Maxwell's demon is a thought experiment on a closed system. This is not a closed system.

I've started to notice

[Anonymous Coward]

that whenever Chinese or Europeans, working in the U.S., come up with something good, which is rather often, websites such as this are almost always crediting it to the university, and effectively the U.S., because they hate to say "Chinese scientists have invented".

Re:Democracy Fail

[Anonymous Coward]

Maos "great famine" killed more than 50 000 000 people.
I bet comrade Mao was a really good "community organizer" ...

Re: Democracy Fail

[Anonymous Coward]

Right. They can go to thier non binary gender freak show refugee rape bathroom somewhere else

Re:Democracy Fail

[amiga3D]

No, fuck you.

He's just trolling

[rsilvergun]

and you just got baited into feeding the trolls...

The anti-Trump crowd over hear considers Trump & Mao to be cut from the same cloth. All just a bunch of dictators (in Trump's case a nascent one, at least right now...).

Re:Democracy Fail

[lucm]

Just WTF are people being taught these days?

Apparently they're not taught the difference between a real comment and trolling

Maxwell's Demon?

[Gim Tom]

This sounds almost like Maxwell's Demon -- which makes me very skeptical.

Re:Maxwell's Demon?

[Threni]

When you figure out that it isn't then you should start to feel better.

My dad sent me this weeks ago

[Anonymous Coward]

I tried to read the paper, but couldn't access it. It sounds like a bunch of horse shit.
A plastic film that converts heat into some form of infrared and then emits so much that it actively cools?
Just think about that for a second.
It would mean that if you have a box of this shit sitting around it would always be several degrees cooler than its surroundings.
If this were real it would be effectively free energy.
Strap this thing some thermo electric device and have it generate infinite energy while sitting out in the sun.

Re:My dad sent me this weeks ago

[budgenator]

It would mean that if you have a box of this shit sitting around it would always be several degrees cooler than its surroundings.
If this were real it would be effectively free energy.
Strap this thing some thermo electric device and have it generate infinite energy while sitting out in the sun.

Yes you could, the efficiency would suck due to low deltaT, but it would be a cool science-novelty type thing.

Dust?

[codeButcher]

I've seen a lot of films and paints the last couple of years using some form of reflectivity to lessen heat absorption. All fine and well until they get a fine layer of dust after a couple of weeks. Then they are useless.

I'm not to well versed in the physics of this (meaning not at all), so I wonder how this invention will hold up under real world dusty conditions.

Re:Dust?

[vannoble]

Just send a guy up the side of the building with a bucket and squeegee like they already do now.

Re:Dust?

[codeButcher]

Just send a guy up the side of the building with a bucket and squeegee like they already do now.

You seem to think of glass-covered skyscrapers, and that this film is to be installed over windows. I don't know that that's the case, as you can see from the photo in the article that the film is translucent, not transparent like a clear window. In fact, the article states that they apply a mirroring backside to the film, which is left off only for photovoltaic application.

The applications I mentioned were applied to both commercial as well as residential buildings, often on the roof, or otherwise under it as either another roofing layer or as a ceiling - and only the outside surface application is amenable to washing.

As to this plastic film, I'm thinking that constant washing will accumulate micro-scratches, and exposure to the sun's UV will discolor or otherwise deteriorate the plastic, both of which MAY alter the effectiveness of this invention. I guess that needs to be seen in practice.

Re:Link to paper...it's actually better than 93W/m

[Anonymous Coward]

Next somebody will get the idea that civilizations everywhere cool their planets by radiating wavelengths not absorbed by their atmospheres. And we'll start searching for such oddly radiating planets.

Re:the radiator will be huge at 50w/m2 for anythin

[Anonymous Coward]

You lost me at "watts per hour".

Check your units. None of it makes sense.

Just in time!

[Anonymous Coward]

Just in time for Global warming!!

Bigot much

[Anonymous Coward]

Are you bigoted against the brown people who work construction or the white people.

No, you fucking tool, the house isn't a pile of unengineered garbage. The house was actually built to code and inspected to code. I'm sure that you could build a perfect house, and that only an arrogant fuck like you would pay that much to save so little. Also, in your ideal wold, if your cat farted, you'd be smelling it for days.

There's a reason houses have to breath some, by code, and a reason they have to be wrapped, by code. There's a reason for the insulation requirements, and a reason that it isn't higher.

Re:Bigot much

[russotto]

Naa, they love talking about the super-insulated houses which require nearly-perfect air sealing (they ventilate through counterflow heat exchangers, so the house can breathe, they HAVE thought of that one). The fact that this nearly-perfect air sealing will never survive ordinary settling and thermal cycling is kind of ignored. And heaven help you if you need to penetrate the envelope... you know, if you want power, telecomm, plumbing, another window, whatever.

Re:the radiator will be huge at 50w/m2 for anythin

[Anonymous Coward]

4 tons is insane. Are you in a McMansion in Phoneix?

What size

[Anonymous Coward]

... indoor temperatures of 68 degrees when it's 98.6 outside.

They've given a temperature of differential of of 17C (30F). For most climes, a differential of 13C is sufficient so the numbers look right. But there are no details: Was the differential calculated for an empty building? When hot motors (elevators, escalators, fans, water pumps) and a 1,000 warm bodies are shoved into a building, even 17C of cooling may not be adequate.

... 93 watts per square meter.

I assume this film can't be put on the external walls because that would be transmitting the heat into adjacent buildings. Will this require giant honeycomb-style radiators on skyscraper roofs to handle the near megawatt output?

Don't worry, he was being sarcastic.

[Anonymous Coward]

The OP was being sarcastic.

Re:its basically a sun shade that you can see thro

[SirSlud]

All it is is a heat disposal system. A building has heat. I'm sure you understand how you can use an IR camera to "see" a heated structure in total darkness. The heat on the inside is absorbed and emitted towards outside in a spectrum that isn't absorbed by the atmosphere. It's effectively "dumped" into space. (And shielded by a mirror that prevents it from absorbing the infrared coming from the sun.)

Physics says its BS.

[thesupraman]

Learn just a LITTLE physics and you will see that YOU are wrong (and TFA).
There is no frequency that does not absorb over atmospheric distances, plus when it hits any solid object.
There are only frequencies with LOWER absorption, which is meaningless for these kinds of path lengths.

In other words, that part of the article is pure BS, which makes the rest smell.. a little off?

The actual cooling mechanism looks dicey but possible, without a more careful analysis.

But the 'radiates out to space' part is put BS.

Re:Physics says its BS.

[habig]

Learn just a LITTLE physics and you will see that YOU are wrong (and TFA). There is no frequency that does not absorb over atmospheric distances, plus when it hits any solid object. There are only frequencies with LOWER absorption, which is meaningless for these kinds of path lengths.

I've learned a little bit of physics, and while technically true, what you say is misleading. Visible light, for example, doesn't absorb very much in air (yeah sure, there's some). The air is "optically thin" at visible wavelengths, which means more light is getting through from space to us than not: 75% of the energy integrated over all wavelengths gets down here: most of what's not getting through isn't the visible bits (yay for the ozone layer).

So, if they can shift energy to come out at 10 microns, which is in a clear bit of the spectrum almost as nice as around 5000 angstroms (visible light), what they say is right: 10 micron IR radiated upwards is mostly checking out back into space.

Just make sure you're not putting the fancy new film under solid objects, go read about the laws of thermodynamics, solve your favorite radiative transfer equation, and *poof*: cooler thing than you had started with.

Re: Physics says its BS.

[Anonymous Coward]

Yeah, pure BS. Has to be. Otherwise you would feel the heat when the sun shines on your skin.

$0.25 per square meter?!

[Anonymous Coward]

The cheapest greenhouse film is $0.10 per square FOOT. That works out to just over $1.00 per square meter...

NEWSFLASH from the future!

[Anonymous Coward]

Senior citizen in Phoenix freezes to death in his home in the middle of summer when he couldn't open a window.

"It's those damn passive coolers', said his son via phone from Boston, "I told him it would suck all the heat out of his house but he didn't listen to me."

Could this technology be used to offload heat from

[Anonymous Coward]

Per subject line

Dammit...

[Trachman]

Trump ordered (or convinced) air conditioning company Carrier to stay in the United States.

I guess because of this invention Trump will now order infrared rays to stay in the United States too so that the Carrier could sell us those AC units.

What happens when it's on something HOT?

[wisebabo]

Ok, so what happens if you put this on something really HOT like a car engine running at 500C or maybe a jet engine at 1000C or a rocket engine at 2000C? (Of course, you'd replace the plastic "film" with something else or perhaps just apply the nano-beads directly.)

Would they REALLY benefit from the "huge temperature difference ... to outer space", so much so that they didn't require complex cooling systems but could instead just radiate their heat directly? (I presume that this would mean the hot parts would need to be directly exposed to the environment; we'll need IR transparent car hoods!). Would power plants be able to forgo the use of condensers used to cool down the working fluid? So no more cooling towers? (Another poster may have implied this by saying the cooling could be much more efficient).

What about OTHER applications of heat re-radiation technologies? If you change the size of the nano-beads you change the emission frequency of the IR, right? How about coating this on surfaces to make aircraft and missiles invisible to the wavelengths used by IR detectors? (Maybe because they track the exhaust plume, still might work to disguise warheads/satellites free falling in space). How about putting this on clothing so that their body heat doesn't show up on IR cameras? (Maybe too broadband to be able to disguise). Of course, if the nano-beads could absorb ALL light and dump it into their narrow emission frequencies, you could get a very good (against a black background) cloak.

If you can make the nano-beads just a bit smaller, you could do the same tricks but with VISIBLE LIGHT. Think paints that would really glow at specific frequencies. Shine a blue light on it and it would glow red! Even if expensive, it could be used for specialized inks (think anti-counterfeiting). Then again, maybe this is the principle behind quantum dots so maybe nothing new.

I'm wondering, can these beads up-convert the frequencies? That is can they take a large amount of long wavelength IR and make it into a lesser amount of short wavelength IR? (It would have to be a "lesser" amount otherwise there would be a violation of the conservation of energy). Would this violate some basic quantum principle? Isn't this what Einstein got his Nobel prize for (the photo-electric effect)?

Many questions, if only I'd studied thermodynamics and quantum mechanics!

Re:What happens when it's on something HOT?

[budgenator]

If you can make the nano-beads just a bit smaller, you could do the same tricks but with VISIBLE LIGHT. Think paints that would really glow at specific frequencies. Shine a blue light on it and it would glow red! Even if expensive, it could be used for specialized inks (think anti-counterfeiting).

That would be a Dichroic filter, that's what's in the reflector in your Dentist's light. It's adjusted to only reflect light frequencies that mimic a 4,500K blackbody.

Re:What happens when it's on something HOT?

[syntotic]

Many questions, if only I'd studied thermodynamics and quantum mechanics!

That is easy: everything cools down, everything has two faces, any illusion to the contrary is your gain and cannot be sustained. IT is the core of IT, in fact. :|

Interesting use of coatings, but...

[Anonymous Coward]

"Atmospheric IR window" is a pretty broad (in terms of nanometers), but I have to wonder how much of an issue this will cause with IRST and AAM? "...fighter pilot under investigation for destroying the Bank of Idgitistan Building during an air-to-air intercept mission" is something we might hear in the news.

Perpetual Motion Machine?

[Nit Picker]

Put this on an insulated box, which then gets colder than its surroundings. Use the box interior as the heat sink for a heat engine with a heat source exterior to the box.

Sounds like boolsheet.

Maxwell would say ...

[Tjp($)pjT]

It's demons I tell you. DEMONS!!!!

Capture the waste heat.

[JimSadler]

Since we have many uses for heat maybe w could capture the heat exhausted from that system as well as use it for cooling. And we just might be able to collect water from that cooled air as well.

Reathal Weapon

[fyngyrz]

It's racist, you plick!

Always listen to your dad

[fyngyrz]

If this were real it would be effectively free energy.

Like that laughable idea, "solar cells." "Electricity from free light." Free energy! I mean, really. What utter nonsense, eh? Some people will believe anything.

Uh

[Anonymous Coward]

Sounds good in the summer but what happens in the winter? Or those of us with a WI Ted are not cool enough for the plastic beads of salvation?

Desert water source?

[Insanity Defense]

Such a film cold on one side hot on the other could potentially be used to condense water from the air on the cold side in a hot environment. Useful in desert conditions.

Re:its basically a sun shade that you can see thro

[budgenator]

Even I can see through this lie. It's really just Maxwell's daemon sorting molecules. Just another BS story on Slashdot that will get hype for a few days and then no product will ever come to market. An obvious clue that even the "inventors" know this is complete bullshit is the claim "All the work is done by the huge temperature difference, about 290C, between the surface of the Earth and that of outer space,". Is anyone buying that crap? 'cause if you don't then it is pretty obvious this can't work.

Abstract: Passive radiative cooling draws heat from surfaces and radiates it into space as infrared radiation to which the atmosphere is transparent. However, the energy density mismatch between solar irradiance and the low infrared radiation flux from a near-ambient-temperature surface require materials that strongly emit thermal energy and barely absorb sunlight. We embedded resonant polar dielectric microspheres randomly in a polymeric matrix, resulting in a metamaterial that is fully transparent to the solar spectrum while having an infrared emissivity greater than 0.93 across the atmospheric window. When backed with silver coating, the metamaterial shows a noon-time radiative cooling power of 93 W/m2 under direct sunshine. More critically, we demonstrated high-throughput, economical roll-to-roll manufacturing of the metamaterial, vital for promoting radiative cooling as a viable energy technology. Scalable-manufactured randomized glass-polymer hybrid metamaterial for daytime radiative cooling

Pretty hard to get your research paper published in the peer-reviewed journal Science, unless it's at least scientifically plausible.