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'Whitest ever' paint reflects 98% of sunlight

bbc.com

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Re: 'Whitest ever' paint reflects 98% of sunlight

#41

Post by throwaway0a5e »

ebiester wrote: post #22
SamBam wrote: post #11

I assume this could be useful to shield something in space with extremely specific temperature tolerances. I'm not sure about the suggestion that people are going to paint their roofs with it. People already have the opportunity to paint their roofs with cheap white paint which would provide nearly all the benefits this would, and still choose not to do it.

What we really need is white paint in the summer, black paint in the winter - reversible roofs, if you will. That said, in the desert southwest and many places in the world, white roofs are common. I wish it were more common in the southeast...

Corrugated material could provide a white surface to the mid-day sun in the summer and a black surface to the mid-day sun in the winter. Of course you'd need to take latitude and roof slope into your calculations but I bet if you made the materials in 10-deg increments you could get something "good enough" for most use cases. Or you could just make the material change color based on temperature.

This is all known science but getting it cheap enough to be used as roofing is the trick.

Re: 'Whitest ever' paint reflects 98% of sunlight

#42

Post by [deleted] »

ebiester wrote: post #22
SamBam wrote: post #11

I assume this could be useful to shield something in space with extremely specific temperature tolerances. I'm not sure about the suggestion that people are going to paint their roofs with it. People already have the opportunity to paint their roofs with cheap white paint which would provide nearly all the benefits this would, and still choose not to do it.

What we really need is white paint in the summer, black paint in the winter - reversible roofs, if you will. That said, in the desert southwest and many places in the world, white roofs are common. I wish it were more common in the southeast...

[deleted]

Re: 'Whitest ever' paint reflects 98% of sunlight

#43

Post by nerdponx »

purple_ferret wrote: post #31
SamBam wrote: post #11

I assume this could be useful to shield something in space with extremely specific temperature tolerances. I'm not sure about the suggestion that people are going to paint their roofs with it. People already have the opportunity to paint their roofs with cheap white paint which would provide nearly all the benefits this would, and still choose not to do it.

NYC roofs are definitely painted with reflective paint. They're usually silver-ish though.

Disappointingly few of them, still. It's always depressing to fly over an area and see nothing but black rooftops, devoid of anything but HVAC equipment. I know green roofs have engineering issues but I hope one day I will instead look out my airplane window and see a sea of solar panels, small wind turbines, and rooftop gardens.

Re: 'Whitest ever' paint reflects 98% of sunlight

#44

Post by buran77 »

Arnt wrote: post #29
buran77 wrote: post #15

Earlier quoted context omitted.

I would expect it's twofold. This paint acts like a "diffuse mirror" so doesn't create any bright spots like specular reflection. This is great particularly in cities where every building would become a giant mirror. On the other hand a mirror finish is harder to achieve on rough surfaces that the paint would presumably be used on.

Adding: Mirrors don't have to reflect very much, they have to reflect as a picture. That's why one-way mirrors work — people generally don't notice that the light mirrored is much less than 100%. White paint is free to reflect the photons in any direction, so that >98% is a harsher requirement on the share of incoming photons, but a laxer requirement on the photons' direction.

Some mirrors can reflect a lot more light even if in narrower wavelength ranges. But that only makes the matters worse from a practical human perspective, when trying to use them on large surfaces outside. It would feel like staring into the Sun far too often.

Re: 'Whitest ever' paint reflects 98% of sunlight

#45

Post by FredPret »

cyberlab wrote: post #4

Someone needs to compile a list of all this fringe tech that I see popping up in my feeds, almost daily now. I know there are techpress blogs that pump out articles like this, but there doesn't seem to be an authoritative compendium of such tech anywhere on the net. I could curate this by hand with 3 hours of free time and some Red Bull I suppose. The reason I want this is because we seem to be swimming in innovation…

Speaking of joining the dots, did you know that both the train and steam power (albeit a toy version of it) were invented in ancient Egypt?

Think what could have been had we joined those two dots in 2000BC instead of 17-1800 AD.

I should note that their train was of course pulled by slaves and not a locomotive.

Re: 'Whitest ever' paint reflects 98% of sunlight

#46

Post by a4isms »

Reminds me of “anti-flash white,” developed for bombers during the early years of the cold war. The theory was that the specially formulated white paint would reflect enough of a nuclear explosion’s thermal energy to allow the aircraft to survive the explosion as the bomber departed the scene.

https://en.wikipedia.org/wiki/Anti-flash_white

It was also used on interceptors like the Avro Arrow prototypes.

Re: 'Whitest ever' paint reflects 98% of sunlight

#47

Post by Tade0 »

I wonder how well it reflects in the atmosphere's transparency window?

I've been following news about materials which reflect in this spectrum so much, that they effectively cool their surroundings, but I understand that this paint, while probably less effective, should be much cheaper.

Re: 'Whitest ever' paint reflects 98% of sunlight

#48

Post by adrian_b »

nvahalik wrote: post #27

Yeah it’s white but does dust and debris still stick to it? If it does, it’ll only be really effective until the next cleaning... and then probably just as good as plain white paint.

They said that they have used an acrylic binder, so this white paint should behave like any other acrylic paint, so it should need periodic cleaning.

What is novel is that they have discovered some new method for preparing the barium sulfate pigment and mixing it with the binder, which allows very small pigment particles, possibly having a certain form, and also a very large ratio between the quantities of pigment and binder in the paint.

Re: 'Whitest ever' paint reflects 98% of sunlight

#50

Post by skykooler »

Timshel wrote: post #17
dejj wrote: post #2

Also: Black 3.0, the purchasable variant of Vantablack For sale at: https://www.culturehustleusa.com/

Nice they have a White 2.0 too since last year (up to 99.6% reflective). And as with Black 3.0 banned for Colour criminals ;).

If that's 99.6% reflective, how is this new paint the whitest ever at only 98%?
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