- cross-posted to:
- hackernews@derp.foo
- cross-posted to:
- hackernews@derp.foo
Ultra-white ceramic cools buildings with record-high 99.6% reflectivity::undefined
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You know what also cools houses down super efficiently?
Trees
Excellent - how many trees can I grow on my roof? Can they be retrofitted?
/s
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I can guarantee that a Rooftop Terrace garden cuts down almost 40% to 60% heat ever reaching the ceiling. If you have enough cover with smaller plants under larger bushes/shrubs/small trees then there will be a cool breeze around the terrace, provide nesting places for small birds and animals, a pocket of nature in an otherwise concrete heat jungle.
The problem is who can afford to maintain the Terrace garden is the bigger challenge. Constantly checking soil, composting, watering, maintenance and just time+expense is usually beyond a lot of folks.
It would be cool to bring back for apartment buildings though
Going back to flat roofs and adding plants and soil to the mix sounds like a recipe for some major water leakage issues.
Would be cool to have rooftop gardens though
Green roof, looks cool, usable space, and helps with cooling. Just damned expensive.
Trees? Not many. Grasses, herbs, wildflowers, and shrubs? Tons of them. And you can pretty easily retrofit over an existing sloped roof. And the weight is no more than a tiled roof.
Wetness could pose a problem to the structure
Not if you use a waterproof base layer. This isn’t some theoretical thing, its tried and tested technology in common use
Well of course you’d use waterproof base layer, typically you’d use several even without the plants. It’s tried and tested with multiple cases of failing with age. That’s the issue. Even just flat roofs have been a failure point even without the plants but soil and plants are a definite concern for builders when talking long term.
Are you a builder? Do you have any experience installing and maintaining green roofs? Your assertion than you’d typically use several waterproofing layers suggests not. I have experience building these systems in the real world and the documentation to support their use. BTW - flat roofs aren’t a thing. Expect in traditional building in desert areas. “Flat” roofs aren’t flat.
I’m a construction engineer, though I think that’s just civil engineer in lot of the world.
BTW - flat roofs aren’t a thing. Expect in traditional building in desert areas. “Flat” roofs aren’t flat.
I assumed everyone knew what I meant. See some apartment building roofs.
Kind of
There are eco apartments (planning idk about practice); grass on the roof and trees growing up the side
Lakehead University Orillia was going to do this for a new building but I don’t know what happened
You know what cools roofs and generates electricity? Magic!
Another trick: bifacial panels oriented to pick up the reflected light from highly reflective roofs
What about Ultra white ceramic trees?
True though this is still practical for folks who live in deserts and other treeless places
They also dampen noise
but trees look gross
NightAHawkinLight on youtube has been working on something similar. same kind of snow-like nanostructure to reflect light away, but with the added benefit of a paint that emits light in a wavelength that travels through the atmosphere without interacting with any of it.
so if you point a painted tile at the sky it will actually cool below ambient temperature, it’s pretty wild https://www.youtube.com/watch?v=N3bJnKmeNJY
Tech Ingredients did a video about it as well. https://www.youtube.com/watch?v=dNs_kNilSjk
The biggest problem with making stuff white and using fancy materials is the amount of crap they get exposed to.
Moisture is one issue, both in the form of water vapor / condensation as well as rain. But there’s also smallish animals, like birds and cats that crawl around on roofs. Not to mention all the insects. Then there is the normal sand and dust in the air, plus all the pollution. Depending on where you live, white stuff gets really dirty within weeks or months.
I work in a white office building and they have it cleaned with pressure washers twice a year, it takes a whole climbing team a good two weeks to clean the whole thing and it looks dirty again after a few months. And that’s just a white form of plastic (HPL) you can blast away on, without causing damage. With these fancy meta materials often they are really fragile and any damage undoes the special properties.
Here is an alternative Piped link(s):
https://www.piped.video/watch?v=dNs_kNilSjk
Piped is a privacy-respecting open-source alternative frontend to YouTube.
I’m open-source; check me out at GitHub.
They could just put a layer of something like Teflon over it. That’s why crosswalk stripes feel so slick.
If you put something over it, it loses it’s reflective properties. Something is only as reflective as it’s upper most layer. Unless you use something transparent, but even things we would commonly think of as transparent usually are only transparent at specific wavelength. And even then it’s probably not really transparent, more like translucent. Not to mention things like internal reflections and wavelength lengthening.
This is a super complex subject with many people all over the world working on it and lots of money being put into it. It likely everything people can think of has been thought of and we need some real effort to get to a workable solution. Since no commercial application has been found, it’s not certain this is a fixable problem.
Too often we see innovative ideas and they are marketed as this is just the first version. We can work out the kinks, extrapolate and get to something real special. In reality this is often not the case, actual limitations apply and not all problems are fixable.
Those are slick from the added glass powder for reflectivity.
Who’s putting Teflon on road stripes…?
Huh, I stand corrected. I could have sworn I read an article linked in a discussion about solar panel roads that said Teflon was mixed in the paint to keep the stripes from getting dirty super fast.
Here is an alternative Piped link(s):
https://www.piped.video/watch?v=N3bJnKmeNJY
Piped is a privacy-respecting open-source alternative frontend to YouTube.
I’m open-source; check me out at GitHub.
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In other news, snow blindness is on the rise in suburbia.
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Super awesome. Not only is it white and shiny aluminum oxide, it uses a nanostructure, as observed on beetles, to maximize reflection, minimizing heat retained.
What’s the gains in contrast to regular white bathroom tiles? (Not a joke question)
The reflectivity of “normal” ceramic is only around 60%
Thanks for following up!
You’re welcome!
But what about it getting dirty and how well does it resist having its nano structure getting damaged? Like, there’s that spray that can make sneakers or clothes virtually stainproof…until you wear them several hours or rub your hand against them.
Probably illegal here because of the high reflective value. Depending on the sun’s position, it could dazzle and blind people, e.g. people driving cars or riding bikes. I know that for this reason, shiny metal roofs are not allowed.
There is a difference between mirror like reflection and diffuse reflection. Mirror reflection is what you get with metal roofs which beam the sun directly to a target resulting in one spot being blinded. Diffuse reflection will spread it around, resulting in more light all around which is what we can handle as humans.
Can mostly handle. Snow blindness is a thing, and that’s all diffuse reflection too, not specular. But it’s unlikely a roof would be such a problem.
The reason for snow blindness is the fact the snow fills such a high portion of the visual field.
Yeah, hence it’s unlikely a roof would fill it to the same extent and wouldn’t be a problem.
We have snow here
It’s not visibly reflective. Yes, it’s white, but it’s cool to the touch because the majority of the energy is radiated out into space via non-visible wavelengths. Someone has already posted a great YouTube video from Night Hawk In Light in a comment where he explains how this tech works and makes his own paint!
Yeah, it’s good to read the article before commenting.
Here’s a link to the Night Hawk video. Good stuff. https://invidious.fdn.fr/watch?v=KDRnEm-B3AI This guy just gives away a formula he developed for the pigment. OG shit.
Him, Thought Emporium and Breaking Taps are in their own league of genius.
I have aluminium foil covering my windows in summer and that doesn’t blind anyone by far, even in full sunlight.
Not everything reflecting is a mirror.
Scotland here. Does this come in black?
Would we ever be able to use a material like this to reflect a significant enough portion of the light falling on Earth to reduce the total heat imparted by sunlight in a meaningful way? Could we use this as defacto ice caps to perhaps reduce global temperatures in any real way?
Probably yeah, but more likely it would have to be atmospheric and not surface based. When Mount Pinatubo erupted in 1991 it was estimated that the global temp dropped about 0.5 degrees C over the ensuing year due to the ash cloud blocking the sun
So the actual solution to climate change is to light everything on fire so the smoke cover cools down earth
Ah, the Dinosaurs solution.
The only feasible plan we have for increasing the albedo of the planet overall is atmospheric engineering. Basically you can make a reflective cloud that’s millions of square miles in area, many orders of magnitude more cheaply than any other kind of structure.
Covering our roofs with it would certainly make a difference. BUT, it works in the winter too, cooling the house when we want it warm. So, that might increase the need for heating in the winter.
Personally, I’m waiting for a commercial product, because my NM house has a large, south-facing stucco wall that is currently white, but not ultra cool white. Given my experience with the house, which is well insulated, I expect I could paint the house with such paint and not need any other cooling, even when it hits 100+F here. That wall is my bedroom wall, and I can feel the heat pushing through it in the late afternoon after a full day of exposure to the sun.
In winter my roof is covered with snow. White roofing would absorb less heat from the snow but that may be a good thing, reduce melting.
Could throw some tarps over it, but that’d be difficult and expensive
Is this what they meant about a “bright future ahead of us”?
Imperial March begins to play
My thoughts exactly at first glance! At least, now we know why some people think storm troopers are so cool.
Next trick: make it into a paint or spray-on treatment.
Better yet, make a giant sheet of it and float it in the ocean to fix the earth’s albedo and stop climate change.
Wernstrom!
First, I’ll need tenure
Done!
The copepods and algaes also need the light to draw down assloads of carbon though. Those tiny creatures suck up staggering amounts.
Oh, great idea! A nanoparticle ceramic aluminum oxide aerosol? What could possibly go wrong? 🤣
lol, it doesn’t have to be aerosolized in order for it to be sprayed. It can come out of a spray hose nozzle and be appropriately viscous. Workers can wear PPD.
You’re missing the point, and even at that: this reply is insanely short-sighted. Aerosolized or atomized, is still fucking airborne nanoparticle ceramic aluminum oxide. 🙄
I didn’t miss the point. You’re not understanding what I’m describing in a sufficiently contained substance that leaves its container and reaches its target surface with practically zero contamination of the local area. With a sufficiently viscous base liquid, it would be fine.
You’ve clearly never worked in any professional (let alone commercial) capacity with the medium(s) you’re championing, and the drive-by downvotes are whingy at best. Reddit will be the frog-boiling death of this platform. 🤦🏼♂️
I see that, rather than make you point with logic and facts, you’d rather just make petty and childish insults while complaining about downvotes. And you think it’s me bringing the bad Reddit influence?
Ah, yes, the ol’ Republican switcheroo. My argument is clear, concise, and factually-based, whereas yours is bluster and conjecture, yet you project your failings onto me in defense?
How typical. Stay in school, kiddo.
Maybe a paint that you put on with a hairy stick brush would be better?
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I would bet there are reasons other than aesthetics at play. That’s the kind of paint you would want to use on your house in the Arizona desert, but I imagine driving by a bunch of houses with 99.9% reflectivity at the wrong time of day would be blinding.
Optimistically, this may be the discovery that leads to our future when everything looks like an iPhone.
Why ceramic and not just paint?
The article addresses that. It is because ceramics are durable while paints and coatings are not.
Seems like the effort involved in putting down paint would outweigh the durability. Perhaps they’re thinking about robots to place the tiles though, like on Starship?
Roof tiles. They want to make these into roof tiles. There is a big picture in the article and they even talk about roof tiles. Did no one read the article?
Most coatings like paint that have this effect include ceramics to do most of the reflection, but the other paint stuff the ceramic substrate is emulsified in does not have near the reflectivity, so you’re impairing yourself if reflectivity/heat rejection is the only goal.
Maybe ceramics were considered more sustainable?
So there’s gotta be a downside to reflecting all this heat though?
I know windows sometimes can focus and reflect the sun setting your neighbours house on fire, birds aren’t going to affected, bugs?
It looks like this reflects and scatters the light, rather than reflects and focuses it. Otherwise it would look like a mirror, not a ceramic.
That would only matter for something that it can focus on, it’s still reflecting. All the heat and at scale it’s not tested.
Adding more heat and heat currents into the atmosphere, cannot be a good thing long term.
Not if it’s reflected back into space.
Where it has to pass through the atmosphere again? With more time to heat up the atmosphere as well?
The answer isn’t this simple, I’m curious why people think they could answer it in a sentence or two.
Radiation is not absorbed by transparent gases. The ground is heated and air heats up by contact. It’s a well known fact that snow radiates back the heat and lowers the overall temperature. That’s how ice age works.
Sure, but there is more than just transparent gases, there is also some solid objects. Those would be heated by outgoing radiation. There is also convection currents that can affect weather and migration patterns…
That’s one part of it yeah, and there is absolutely no scientific data on the resulting reflection issues. It’s also funny that ice age answer kinda proves my point, if sheets of ice can make an ice age worse… yeah coating a bunch of stuff with this will absolutely affect stuff. And you are claiming it won’t? Because this answer directly contradicts your previous ones….
Can I see your sources I’m actually quite interested in this and I’m surprised people are answering this with grade school level answers that aren’t even close to being correct.
Of course it will affect stuff: it will cool it down. It’ really very basic. Scenario 1:
- bunch of photons (energy) comes from space
- hit the earth and heat it up
- the heat is transferred to air by contact
- the air heats up
Scenario 2:
- photons heat white surface and are scattered around
- some scattered photons will hit other things but not all of them, most will just fly back into space without transferring energy
- the white surface doesn’t heat up as much as ground
- less heat is transferred to air bu contact
- air is cooler
And all the greenhouse gases it will heat up as it passes through them? You can’t just ignore these gases…
It’s not that simple, and you claiming it is show you have zero understanding of the potential issues. Your ice age example shows that it can affect the globe at scale. Thank you for part of the answer, I’m surprised you’re still arguing after proving my point.
I’m not arguing it’s not going to affect the globe at scale (even though you would have to cover shitload of building in this to affect it). I’m saying that we know what the effect would be: it would cool it down.
What you fail to understand is that if solar radiation hits a dark surface, like a roof, this energy is transferred to earth. That’s it. It’s here. Now it’s really difficult to get rid of it. Greenhouse gases make this even more difficult.
But if solar radiation hits a white surface SOME of this energy will be reflected back to space. Not ALL of it, some of will still stay here but overall it will LESS energy.
Greenhouse gasses trap the radiation emitted by earth as heat, not the reflected light. Think about it. If greenhouse gases reflected light then we would get less light from the sun, right? Part of it would be reflected. They don’t do that. They let light pass through and stop the heat radiated from earth. If you reflect light instead of trapping it that’s a good thing.
This is so basic I’m starting to suspect you’re just trolling so I will end this conversation here…
If the light hits the ground and is scattered then nearly all of the energy stays in the planet and eventually heats the atmosphere. If it’s reflected, even though it must pass through the atmosphere again, some of the energy is rejected back into space.
If the top of my head
- it cools your house in the winter, too
- It’s probably annoyingly bright if you can see the roof from ground level
- likely to degrade over time necessitating replacing tiles to maintain the effect
- Doesn’t work as well if you’ve got solar panels or trees obstructing it
- other stuff, probably
Ceramic is brittle. Ever heard of hail?
