Whitest-Ever Paint Could Help Cool Heating Earth, Study Shows (theguardian.com) 123
AmiMoJo shares a report from The Guardian: The whitest-ever paint has been produced by academic researchers, with the aim of boosting the cooling of buildings and tackling the climate crisis. The new paint reflects 98% of sunlight as well as radiating infrared heat through the atmosphere into space. In tests, it cooled surfaces by 4.5C below the ambient temperature, even in strong sunlight. The researchers said the paint could be on the market in one or two years. Currently available reflective white paints are far better than dark roofing materials, but only reflect 80-90% of sunlight and absorb UV light. This means they cannot cool surfaces below ambient temperatures. The new paint does this, leading to less need for air conditioning and the carbon emissions they produce, which are rising rapidly.
The new paint was revealed in a report in the journal ACS Applied Materials & Interfaces. Three factors are responsible for the paint's cooling performance. First, barium sulphate was used as the pigment which, unlike conventional titanium dioxide pigment, does not absorb UV light. Second, a high concentration of pigment was used -- 60%. Third, the pigment particles were of varied size. The amount of light scattered by a particle depends on its size, so using a range scatters more of the light spectrum from the sun. The researchers said the ultra-white paint uses a standard acrylic solvent and could be manufactured like conventional paint. They claim the paint would be similar in price to current paints, with barium sulphate actually cheaper than titanium dioxide. They have also tested the paint's resistance to abrasion, but said longer-term weathering tests were needed to assess its long-term durability.
The new paint was revealed in a report in the journal ACS Applied Materials & Interfaces. Three factors are responsible for the paint's cooling performance. First, barium sulphate was used as the pigment which, unlike conventional titanium dioxide pigment, does not absorb UV light. Second, a high concentration of pigment was used -- 60%. Third, the pigment particles were of varied size. The amount of light scattered by a particle depends on its size, so using a range scatters more of the light spectrum from the sun. The researchers said the ultra-white paint uses a standard acrylic solvent and could be manufactured like conventional paint. They claim the paint would be similar in price to current paints, with barium sulphate actually cheaper than titanium dioxide. They have also tested the paint's resistance to abrasion, but said longer-term weathering tests were needed to assess its long-term durability.
This paint is so white (Score:3, Funny)
That the GOP has made it their 2024 presidential candidate!
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That the GOP has made it their 2024 presidential candidate!
Close, I heard they'll use it to *paint* The Capital Building when Trump loses in 2024, so ... progress?
Cars etc (Score:4, Interesting)
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White roofs have been a thing for decades, extra white neither here nor there in reality because dirt, dust and UV rays degrading paint, so white good enough, extra white pretty pointless but hey how about bitumen, no more black bitumen but painting roads will make them slipperier, cost a lot and require continuing maintenance. Could require land owners to paint over the car parks, especially malls but hey large empty car parks for malls is already pretty dumb. They should have a concrete slab placed above
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Start putting town houses above car parks, every single mall world wide.
"She shops all the time...I swear it's like my wife LIVES at the mall."
"Dude, you have NO idea."
Re:Cars etc (Score:5, Interesting)
The thing it makes sense to build over parking lots is solar power.
Putting buildings above them requires extensive and thus expensive support structures. Solar panels don't require quite so much structure.
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Cars get hot because of air conditioning.
AC enables the new fashion for sloping windscreens that make them into glass houses. So now AC is not optional -- you need it to solve the problem that it caused.
And make sure you keep that sloping windscreen clean.
Nothing to do with paint colour.
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We just can't call it "white" or as Stewie says "whhite".
Instead we use the more accurate and less offensive "most completely visible light and UV reflective paint".
MAMCVLAUVRA!!
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Will they demand an equal amount of earth be covered in vanta black?
Uh, I'm pretty sure that happens on the regular already.
Long before people woke up.
We call it "night".
Re: *Want* America White Again (Score:1)
Just fixing the slogan; "Want America White Again", or WAWA. little cry babies...
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Nice but how easy is it to keep it clean? (Score:3, Insightful)
As we all know white doesn't stay white for very long when outside.
Had a quick search in the article but it didn't seem to cover that bit.
Maybe there's some nano-tech coating that could be used with it?
Re:Nice but how easy is it to keep it clean? (Score:4, Insightful)
Stain-resistant paint exists, either as coatings or additives. And hopefully this paint doesn't break down and yellow in UV. Most likely there would be some compromise on reflectivity when designing a practical version, but in terms of research for material science this paint has created new knowledge.
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Yet it is prone to dust and dirt. And that means over for extreme white.
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Paints based on Barium sulfate have been marketed in France since 1830 as "Blanc fixe".
That name specifically refers to such paint not yellowing or otherwise degrading over time.
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That particular problem was a problem when one of the commonest white pigments was lead carbonate [wikipedia.org] (either natural mineral cerrusite, or manufactured), which had a tendency to react with sulphuric acid rain to give yellow stains of galena (lead sulphide). This shouldn't be such a problem these decades with less grossly acidified rain, and less lead too.
I think there may have been a sim
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Next time you shit on something, look down first maybe? "As all we know" means "as all you know". And the three idiots who modded you insightful are probably allergic to reading an article, and the related bits.
Incoming karmic poo, on your head.
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Painting stuff white and generally paying attention to how much light materials absorb can make a considerable difference in a city and can compensate for general warming but making things just a bit extra white is pointless. Merely good for laboratory experiments.
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This is 'white' *beyond* the visible spectrum. It doesn't absorb UV light, which current white paints do. That is important, because it reflects significantly more energy, shouldn't yellow because of UV light, and the article mentions it radiates infrared at a frequency that isn't absorbed well by air; it radiates back out to space.
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However, using barium sulfate as a pigment is noting new. White paint based on barium sulfate pigment has been marketed as "Blanc fixe" in France since 1830.
And it has been used for a long time where reflection int he UV spectrum was desirable.
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I think in terms of total amount of covered surface after a year of use. How much energy is there in the IV part? I know UV has more energy per photon but a lot less photons reach the surface. Don't even bother with UVC. How much UV? 5%?
The first challenge would be a material which can be used on a lot of surfaces so you can hope to reduce the absorption by say a third. Non porous roof tiles which reflect well after long use.How do you make asphalt which reflects well. Do we start using white tyres?
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"Air" generally doesn't absorb much in the infra-red part of the spectrum. As any astronomer can tell you, what does the absorption is water vapour and carbon dioxide.
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Side effects include... (Score:1)
Muscle paralysis, including respiratory paralysis, leading to death. At least titanium dioxide probably only causes infertility.
Safety hazard (Score:1)
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Harmful to eyes? (Score:1)
Sounds like it reflects so much sun it could harm peoples eyes
it..cools? (Score:3)
>> In tests, it cooled surfaces by 4.5C below the ambient temperature, even in strong sunlight.
I am not in phisics but AFAIU in order to "cool" one have to remove energy from the object being cooled. So the paint would have to actively emitt energy and well the best emitters are not while, are they? Perfect black body comes to mind but this probably would not work well in direct sunlight?
So can you explain the process by which the white paint is able to cool below ambient? Is this Maxwell's demon then ;-)?
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>> In tests, it cooled surfaces by 4.5C below the ambient temperature, even in strong sunlight. I am not in phisics but AFAIU in order to "cool" one have to remove energy from the object being cooled. So the paint would have to actively emitt energy and well the best emitters are not while, are they? Perfect black body comes to mind but this probably would not work well in direct sunlight?
So can you explain the process by which the white paint is able to cool below ambient? Is this Maxwell's demon then ;-)?
Everything else is absorbing more energy and getting hotter. This object isn't, so doesn't.
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We did this little experiment in elementary school, where we would take two jars filled with water and screwed tight. One of the jars was painted black, the other was covered in aluminum foil and then we put it out in the sun for a couple of hours.
After that we opened it and measured the temperature. But the way we learned it was that the jar with the darker coat absorbed more of the sun's energy and therefore got warmer. They
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That would be my undrestanding - a black body will absorb EM energy from the outside well and also emitt some EM as well. The ratio of absorb/emit is dependent on "temperatures" of the EM radiation and the object.
Here we have a white body, in order to reflect the solar radiation (kinda definiton of 'white'), but also not reflecting the radiation from the object that it is covering and in fact somehow "sucking" out energy from it and emitting to the outside. So it would follow that the paint is "directional"
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For example if we could use frequency doubling on far IR to create even something like near IR we could then use photovoltaics to turn waste heat into useful electrical energy again, which would come pretty close to perpetual motion and would solve a lot of our energy problems.
Now I'm not one of those skeptics who watches a video on youtube seeing some guy pouring water into a container
Re: it..cools? (Score:3)
Not getting hotter is not what they claim. The claim is "getting colder than ambient", even in full sun. I suppose the interpretation here is "getting hotter slower then ambient is" and not that it is actually making things cold. Do nothing special here just a strongly reflecing paint and twisted marketing.
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The claim is "getting colder than ambient"
In the words of a know-nothing "science reporter".
Re:it..cools? (Score:5, Informative)
It radiates mid IR that goes through the atmosphere and into space.
Like: https://www.goodnewsnetwork.or... [goodnewsnetwork.org]
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Re: it..cools? (Score:2)
Convective heat loss exceeds heat gained from direct illumination? Literally not rocket science.
Re:it..cools? (Score:5, Interesting)
So can you explain the process by which the white paint is able to cool below ambient? Is this Maxwell's demon then ;-)?
Thermodynamically, any surface that is poor at absorbing light will also be poor at emitting it. But that can still vary by wavelength.
The paint is highly reflective in visible and UV light. But not IR. It will absorb IR and also emit IR.
Sunlight is mostly visible light, which is reflected. Ambient heat is mostly IR, which is emitted. So the net result is cooling below the ambient temperature of other surfaces.
Conduction and convection? (Score:5, Informative)
I was having trouble understanding how this can cool objects to below the ambient temperature. There are three forms of heat movement: radiation, conduction and convection. This stops (nearly) one form, radiation. If they're measuring the temp of solid objects, then convection wouldn't be a factor. I would have thought conduction would keep objects painted with this at the ambient temperature.
So I skimmed the original article (it's behind a paywall, but...). It turns out the relevant fact--not mentioned in this summary--is its emissivity, which happens to be high in the "sky window" at 9 microns (long infrared): 0.96. So effectively it's radiating infrared out to outer space.
Because of that emissivity, the coating is even more effective at night.
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It will only work with clear skies, though. Not with clouds and possibly also not with the smog haze that is common in urban areas when there is little wind. I couldn't find transmission spectra of the atmosphere under different metrological conditions, though.
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For the purposes of humor play on words aside, while there are certainly idiots that will get offended by the scientific names of things, is this really that much of an issue as some of the commenters here make it out to be?
Though I also have trouble understanding how this can cool objects to below the ambient temperature. Being able to radiate thermal energy at shorter wavelengths won't do that on its own. At lea
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My limited understanding is that the universe is cold, and that's why this works: it's radiating IR (longer wavelengths) into the black universe. It only works well under clear skies (as hankwang suggests above), but it apparently can work even in the daytime, as the Wikipedia article on "Radiative cooling" says, quoting Lim, XiaoZhi (2019-12-31). "The super-cool materials that send heat to space". Nature. 577 (7788): 18–20. doi:10.1038/d41586-019-03911-8. PMID 31892746. (Probably behind a paywall--
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I suppose they define ambient temperature as the average temperature of everything around the object as indicated by the thermal images that they use. Then by definition the object that doesn't heat up as much as the rest would be below ambient.
The definition of ambient that I am used to when it comes to cooling is it is defined by the temperature of the medium that surrounds the object as in the temperature of the gas (air) or liquid.
Here it's important to keep in mind t
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Does not apply here but you missed advection.
or he'll copyright it (Score:3)
Nobody tell Anish Kapoor.
Bill Clinton tried to promote reflective roofs (Score:3)
Bill Clinton tried to promote white and reflective roofs decades ago.
Where is that effort now? I'll hang up and listen for your answer.
Re: Bill Clinton tried to promote reflective roofs (Score:4, Insightful)
The correct method to reduce heat from travelling from your roof shingles down into your house is to 1) vent the attic and 2) insulate your attic floor. Which also saves you on heating costs in the winter. And doesn't look ass-ugly or run the risk of the Russians mistaking your house for an ICBM launch.
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Re: Bill Clinton tried to promote reflective roof (Score:2)
Man builds shelter to protect himself from cold in the winter.
Next week's lesson will be on the benefits of agriculture over hunting and gathering.
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yeh i suppose you dont stop at red lights, or slow down near schools, damn it if you want to drive on the wrong side of the road, fuck the world, its your freedom.
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Re: Bill Clinton tried to promote reflective roof (Score:1)
Yeah. Setting *my* thermostat where I like it is exactly like laying a turd in *your* breakfast cereal. Get help. Preferrably from a shrink who isn't too woke to tie his own shoes.
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No you are the one who needs to visit a shrink because you dont appreciate your selfish actions have consequences and you more importantly you dont give a fuck or try and do your bit.
Whats with america and shrinks ? On tv and movies its always shrinks ?
Re: Bill Clinton tried to promote reflective roof (Score:1)
Your presumption that you have a stake and a say over what I do by myself in my own house is why I also keep a gun in my house. Also an American custom. To head off exactly these kinds of disagreements.
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you obviously have a reading problem i never claimed any authority.
> in my own house is why I also keep a gun in my house. Also an American custom. To head off exactly these kinds of disagreements.
oh yes the american hero with a gun, except he is actually a coward because when it really counts and theres a masscare the american hero is never to be seen in 99% of cases.
Re: Bill Clinton tried to promote reflective roof (Score:1)
Is this fun for you? I admit I enjoy it, but every so often I feel like I'm taunting a retarded child with a calculus question.
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Big words. THen again i can appreciate why you *think* you need a gun, the ansewr is of course you see many other people just like you all around, big fat aresholes who only think of themselves and we all know where that goes.
Re: Bill Clinton tried to promote reflective roof (Score:2)
I see most of those people minding their own business. I also see a small number of busybody control freaks like you presuming to tell me how to live inside my own house and justifying that intrusion to yourselves with talk of moral superiority and concern for the vague future or equally vague common good. And I see in history that your particular brand of religious or quasi-religious fervor and self-assured righteousness tends to be the most dangerous. Which is why I keep a gun un the house.
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Of course most people are fine, it only takes one psycho with a gun to have a masscare.
> I also see a small number of busybody control freaks like you presuming to tell me how to live inside my own house and justifying that intrusion to yourselves with talk of moral superiority and concern for the vague future or equally vague common good.
The same attitude as drink drivers who justify their own self importance to ignore basic rules for the
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or run the risk of the Russians mistaking your house for an ICBM launch.
Good safety tip, but we should be careful taking this too far. Mastodons roaming the rural streets might mistake a white SUV for a potential mate.
Between that and the Russians assuming your hay barn is a new cold-war silo...I mean you don't wanna get fucked.
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Where is that effort now? I'll hang up and listen for your answer.
Same place every effort is when no one listens or gives a shit. What was "promoted" in the USA is standard practice in many countries. Ever been to Greece? https://en.wikipedia.org/wiki/... [wikipedia.org]
Could it be better than photovoltaic? (Score:2)
Installing photovoltaic in the built environment offsets the energy usage of buildings. But such arrays are also dark by design, because they are absorbing solar energy. What is the comparative effect of using this white on the roof instead in hot climates? You would not be collecting any energy, but there would be a lot less sunlight being absorbed by the roof.
Yesss, finally my perpetual motion machine (Score:2)
1. Put up 2 huge objects, one painted with this paint
2. Setup a heat engine between the 4.5ÂC temperature differential of the 2 objects
3. Keep buying dogecoins with the profit. Perpetually.
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One big problems (Score:2)
Aliens will the glow as an interstellar truck stop from 25 light years.
Insulation (Score:4, Insightful)
This paint thing is a the case of an invention looking for a problem, unlike proper insulation this paint only helps reduce heat, not keep the building warm during a cold day. It may have some uses in specialist applications but it really isn't something that has any place in general construction.
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You have failed to understand the invention. Insulation doesn't create a cool surface below the ambient temperature and insulating buildings won't cool the earth's surface either. Unless you coat the outside of the insulation in this material or another material that can radiate energy in the far IR.
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So no, insulating a hot roof from a cooler building is still the much b
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The higher the temperature a surface coating is, in general, the shorter the time it lasts. Keeping the surface temperature of your roof cool is a good idea, unless you want to be repairing it frequently.
Keeping your roof cool is a separate, but related, consideration to insulating your house.
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Just insulate the building, it doesn't matter how hot the outer skin of a building gets if it is well insulated. The reason we spend so much on heating and cooling is because traditionally homes and offices have been built down to a cost. Low construction costs but high running cost suit the developers because they are not responsible for the running costs.
This paint thing is a the case of an invention looking for a problem, unlike proper insulation this paint only helps reduce heat, not keep the building warm during a cold day. It may have some uses in specialist applications but it really isn't something that has any place in general construction.
Heating is a lot cheaper than cooling. If this paint helps keep a building cool it could be well worth it.
If anything, houses are over-insulated these days. You have to either open all the windows (which has issues of its own) or you end up needing to air condition when it's 60F, so much heat gets trapped.
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Heating is a lot cheaper than cooling. If this paint helps keep a building cool it could be well worth it.
Depends entirely on local climate. We pay a full order of magnitude more for gas heating than cooling per year.
Lets assume a hot summer day is 95 degrees and a cold winter day is 25 degrees.
95 - 72 = 23
72 - 25 = 47
As you can see for all but southern states delta-t is roughly 2x for heating in Winter vs cooling in Summer.
I'll gladly take whatever I can get from the sun even if it slightly increases AC costs for a third of the year AC is used because 2/3 of the time it is helping to mitigate substantially hi
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Heating is a lot cheaper than cooling. If this paint helps keep a building cool it could be well worth it.
Depends entirely on local climate. We pay a full order of magnitude more for gas heating than cooling per year.
Lets assume a hot summer day is 95 degrees and a cold winter day is 25 degrees.
95 - 72 = 23 72 - 25 = 47
As you can see for all but southern states delta-t is roughly 2x for heating in Winter vs cooling in Summer.
I'll gladly take whatever I can get from the sun even if it slightly increases AC costs for a third of the year AC is used because 2/3 of the time it is helping to mitigate substantially higher heating costs.
In places like Portland and DC for example having a white roof is guaranteed to cost you more in yearly energy costs.
No, I mean that literally heating is way cheaper than cooling, even for one degree.
Making heat is easy. Pumping heat out is hard.
Even in northern states, the summer electric bill is way worse than the winter gas bill.
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No, I mean that literally heating is way cheaper than cooling, even for one degree.
Making heat is easy. Pumping heat out is hard.
Even in northern states, the summer electric bill is way worse than the winter gas bill.
Our highest combined monthly gas+energy rates are by far in the winter months. We pay about $100 in AC power costs and $1000 in gas heating per year.
CoP of a typical forced air AC system is ~4.0
Resistive heating 1.0.
Gas heating 0.80-0.98
Heat pump 2.5-3.0
There is roughly a 2-4x cost advantage of gas vs resistive heating on a joule for joule basis depending on market.
Neither in terms of energy or cost is AC more expensive than heating.
Once you factor in the fact heating in Winter months has double the delta-
Toxicity ? (Score:2)
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Keep it away from Vanta Black (Score:2)
Because that might end up over spinning the planet. (to be clear, it's a radiometer reference)
Occupational Exposure limit (Score:2)
Interesting, wikipedia says it is the same stuff as what you drink for x-rays, the radiocontrast agent barium sulphate. Toxic, except it is virtually insoluble in water so nontoxic.
In regards to occupational exposures, the Occupational Safety and Health Administration set a permissible exposure limit at 15 mg/m3 while the National Institute for Occupational Safety and Health has a recommended exposure limit at 10 mg/m3. For respiratory exposures, both agencies have set an occupational exposure limit
Changing of the seasons (Score:1)
Everything is wrong (Score:2)
I could see this story appearing on April 1. Just about everything in it is wrong;
1) Cooling a surface below ambient-- see "Thermodynamics". Can't happen.
2) Costs less-- see "Economics". Things with benefits cost more.
3) Costs less-- see "Economics". If it's 90% pigment, it's not going to be cheap.
4) New discovery-- see "History". Barium sulphate has been used as a reflectance agent for 135 years.
5) Feasibility-- see "Geography". The percentage of rooftop area on the planet's surface is m
Vantawhite (Score:2)
Maybe another (or the same!) stupid yet overpaid artist will get an exclusive license to this paint, so that only they get to enjoy its unique qualities.
In celebration... (Score:3)
In celebration of this momentous invention, let's paint the town red!
Whitest-Ever Paint Could Help Cool Heating Earth, (Score:1)
Re:white paint does nothing for climate (Score:5, Insightful)
It doesn't just reflect heat into space... it reduces the energy requirements of the building underneath it, which means less energy generation, which means less carbon release, which reduces the greenhouse effect.
Still likely tiny compared to how much we dump into the atmosphere every day, but it's still something, and it comes with the side effect of creating a relatively short-term financial incentive to encourage its use.
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exactly the solution to climate change isn't one thing that makes all the difference, its a combination of some big things, and many many small things that when combined make a substantial impact
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Re:white paint does nothing for climate (Score:5, Informative)
Simplistically speaking the difference between a perfect mirror and a perfect white surface (perfect in the sense that they work over the entire spectrum) is that the white surface scatters the light into all directions, while a mirror maintains the angles of the waves or rays if you will (angle of reflection equals angle of incidence).
Which one is 'better' in an engineering and economic sense would be the one that's easier and cheaper to construct, operate, and maintain.
Re: white paint does nothing for climate (Score:2)
What special about a mirror is it is flat and smooth. It herefore reflects the light in a consistent direction. Hence when looking in a mirror the color of your lips doesn't show up on your forehead. Stand next to a white wall while wearing a red shirt and you'll be a big undefined blob of red reflected in the wall.
A mirror isn't particularly good at reflecting a lot of light - it's just a metal surface. What it's good at is having the reflection be "in focus".
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All we need to do for global warming is paint all the trees with this new white paint.
Think I'll start writing the grant application today...
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No, your bathroom mirror with aluminum on glass is about 90 percent reflective. Go look at prices of "optical mirrors", that's expensive stuff!
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let's talk about blackbody radiation then
Re: White Privilege! (Score:1)
Can't. A white dude (and a German no less) came up with the math (also racist) to describe it.
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You forgot to add some 1s between rows of exclamation marks to show how angry you are.