'Whitest ever' paint reflects 98% of sunlight • Hacker News Board

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

#261

Post by loonster » Sat, Apr 17, 2021, 2:35 PM UTC

renox wrote: post #250

clairity wrote: post #220

Earlier quoted context omitted.

yes, there's no experience or incentive for better knowledge in big box stores unfortunately. i've moved on to buying from a local paint specialty store, which is owned by a family that i believe is/was in the construction/painting business. they cater mainly to contractors but also sell to the wider public. oh, and yeah, paint and primer in one does neither job very well.

Yep, been there too: paint is really something where you want to avoid the big shop and goes to speciality stores instead (paint peeling from the wall? Color changing after a year? Done and done --> switched to a dedicated paint store == no more issues, the paint itself is more expensive sure but the result is stable)

Paint peeling could also be a humidity issue. I had paint peeling on my ceiling due to water problem in the basement.

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

#262

Post by jokethrowaway » Sat, Apr 17, 2021, 4:39 PM UTC

Red_Leaves_Flyy wrote: post #88

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…

I think part of they problem is that whoever invented this paint is going to want a massive premium for its sale. So it'll get some niche industry use until the patent expires and people start painting their desert roofs with it, or whatever else. Apply to this virtually every technical innovation that is iterative. Fundamental breakthroughs allow for a shakeup of the incumbents, iterative ones don't, due to the arch…

Or get rid of patents entirely and let innovation and copying happen freely. I already ditched all my physical startup ideas because China could clone any of them in half a day and I think it's fair: they have superior / more efficient manufacturing available. Similarly I don't see why discovering something should force everyone else on the planet to give you money.

In this particular case, thought, the article claims they won't be patent trolls and this paint should be cheaply available.

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

#263

Post by arp242 » Sat, Apr 17, 2021, 6:07 PM UTC

spiritplumber wrote: post #240

legulere wrote: post #218

Earlier quoted context omitted.

Like how elephants were greatly reduced in numbers to make billiard balls?

I'm more thinking like cows

Cows are fairly peaceful animals that naturally live in a herd and have been domesticated for thousands of years (people can get killed by cows, but it's rare).

Bears are huge ferocious animals that typically live solitary lives and will kill you and your entire family while hardly breaking a sweat.

Keeping polar bears "like cows" sounds like some good comedy sketch material.

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

#264

Post by CalvinBarrows » Sat, Apr 17, 2021, 7:38 PM UTC

I'm thinking of using this technology on trains - particularly Metros/Subways

https://news.railbusinessdaily.com/a-reflective-perspective-...

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

#265

Post by RichardHeart » Sun, Apr 18, 2021, 9:15 AM UTC

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…

Perhaps this list works? https://en.wikipedia.org/wiki/List_of_emerging_technologies

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

#266

Post by citrin_ru » Sun, Apr 18, 2021, 10:18 AM UTC

rtkwe wrote: post #21

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.

White roofs don’t look great which is why I think they’re largely relegated to commercial buildings instead of residential ones. They get dirty fast, are super bright and don’t fit with the traditional look for houses. On commercial flat top roofs they are hidden so it doesn’t matter if they’re blindingly bright or stained because they’re not visible.

> White roofs don’t look great

What looks great and what is not significantly affected by what are you used to see. In the place I've ground up galvanized steel roofing was common and I think it looks fine. But someone who used to dark roofs likely would tell that galvanized steel looks ugly.

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

#267

Post by citrin_ru » Sun, Apr 18, 2021, 10:22 AM UTC

dieortin wrote: post #51

Tade0 wrote: post #39

Earlier quoted context omitted.

Black in the winter would make the building lose heat faster - especially during the night.

How so? It would absorb more radiation from the sun. In cold European cities the roofs are traditionally black.

At winter day is shorter than night and even during the day sun is relatively low so for black roof would likely emit more energy than adsorb.

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

#268

Post by citrin_ru » Sun, Apr 18, 2021, 10:35 AM UTC

ping_pong wrote: post #202

the8472 wrote: post #155

If the goal is to keep buildings cool you don't want your paint to be as reflective as possible in the whole solar spectrum. You want it to have a low reflectivity (thus high absorption/emissivity) in the infrared window[0] where you'll emit more into space than you'll absorb and high reflectivity in the rest of the spectrum. [0] https://en.wikipedia.org/wiki/Infrared_window

It won't get reflected back into space. It will get reflected back to us because of the Greenhouse effect, and it will just keep warming us up. We need to have solar panels to convert that into electrical energy.

Greenhouse effect reflects back to us a small fraction of energy, most of reflected light will go into space.

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

#269

Post by btbuildem » Mon, Apr 19, 2021, 4:31 PM UTC

toss1 wrote: post #169

btbuildem wrote: post #163

White roofs are great -- just like snow, the high albedo means a lot of the heat energy is reflected not absorbed. But.. the ultra-white paint, on a roof? Perhaps it will be ultra-white on the first few days. Rain, pollution, dust, smog, and a myriad of other particulates (esp. in an urban setting) will quickly render it off-white, and bring it on par with existing finishes.

It seems the existing finishes would also degrade along exactly the same curve. Starting at a higher point on the curve might leave this finish, in it's environmentally degraded state, still brighter than the other white finishes when new, and certainly brighter after both are exposed. Also, if this were that big a problem, it seems that solar panels would fail. It seems that rain often counteracts the pollution, dus…

I think it's a cost-benefit balance. Anecdotal, but when you see things bleached by the sun, they're pretty white -- not ultra #FFFFFF white, but pretty white. My roof is done with a modern membrane, which is very light gray in appearance, with tiny white stones embedded in it.

I imagine you can take a roof like that (say 80% albedo) vs a high-tech ultra-white (99.9% albedo), and the 80% roof won't degrade in reflectiveness because the sun naturally bleaches things to that level -- but the wear and tear of high-tech roof will bring it down to about the same.

Just musing here, no solid evidence to support this.

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

#270

Post by spiritplumber » Wed, Apr 21, 2021, 2:09 AM UTC

arp242 wrote: post #263

spiritplumber wrote: post #240

Earlier quoted context omitted.

I'm more thinking like cows

Cows are fairly peaceful animals that naturally live in a herd and have been domesticated for thousands of years (people can get killed by cows, but it's rare). Bears are huge ferocious animals that typically live solitary lives and will kill you and your entire family while hardly breaking a sweat. Keeping polar bears "like cows" sounds like some good comedy sketch material.

Counterpoint: we did it with wolves.