Energy Free Cooling through Physics

[Xist]

Does this video just describe UV coating glass with extra steps? It does apply to other materials, which is wildly different, but for glass, it just sounds like a more complicated way to UV coat it.

https://www.youtube.com/watch?v=2iwXdGxyzYw

[freebeard]

Does this video just describe UV coating glass with extra steps?

No.

I understand that it's a cofusing video. The 'now with ray-tracing' animations are unhelpful. Start here: en.wikipedia.org/wiki/Infrared_window

aerohead and I engaged on this in the absorption AC thread from Permalink #11 to #25. In preparing this response I learned that there are three atmospheric windows. IR is the one in question, between 8 and 14 μm.

aerohead's objection was that there are more gases than CO2 and water vapor. Turns out that ozone is third most impoortant.

Anyways, to answer your question, no -- not just glass.

Ultrawhite paint with [IIRC] barium phospate pigment works; and there is SkyCool. www.skycoolsystems.com/technology/ and their Dual-mode Film. Seven alternating layers of sputtered coatings IIRC.

[freebeard]

I read ther news today, oh boy....

phys.org: World's whitest paint now thinner than ever, ideal for vehicles

The original world's whitest paint used nanoparticles of barium sulfate to reflect 98.1% of sunlight, cooling outdoor surfaces more than 4.5°C below ambient temperature. Cover your roof in that paint, and you could essentially cool your home with much less air conditioning. But there's a problem.

"To achieve this level of radiative cooling below the ambient temperature, we had to apply a layer of paint at least 400 microns thick," Ruan said. "That's fine if you're painting a robust stationary structure, like the roof of a building. But in applications that have precise size and weight requirements, the paint needs to be thinner and lighter."

That's why Ruan's team began experimenting with other materials, pushing the limit of materials' capability to scatter sunlight. Their latest formulation is a nanoporous paint incorporating hexagonal boron nitride as the pigment, a substance mostly used in lubricants. This new paint achieves nearly the same benchmark of solar reflectance (97.9%) with just a single 150-micron layer of paint.
...
"The models showed us that the nanoplatelets are more effective in bouncing back the solar radiation than spherical nanoparticles used in previous cooling paints," Katsamba said.

The paint also incorporates voids of air, which make it highly porous on a nanoscale. This lower density, together with the thinness, provides another huge benefit: reduced weight. The newer paint weighs 80% less than barium sulfate paint yet achieves nearly identical solar reflectance.

So particle shape and entrained air bubbles optimize the performance. The material is obtainable. Car paint typically is 40 microns eac for primer, color and clear coats; so 40 microns for primer and 150 microns for the3 Ulta White.

Then Turtlewax protective coating with graphene for a hydrophobic surface.

[redpoint5]

Read the news, or listened to The Beatles?

So it's more than 3x thicker than normal color coat?

Maybe we should mandate white cars by law, you know, to help the global warming.

What part of sunlight causes the most warming? I'd expect infrared, but I never thought to ask before. Clear coats absorb UV, so if that causes warming then that's no good.

[freebeard]

let's ask DDG: duckduckgo.com/?q=energy+in+sunlight+spectrum&ia=web

https://en.wikipedia.org › wiki › Sunlight
Sunlight - Wikipedia
In terms of energy, sunlight at Earth's surface is around 52 to 55 percent infrared (above 700 nm ), 42 to 43 percent visible (400 to 700 nm), and 3 to 5 percent ultraviolet (below 400 nm). [7]

The paint is re-radiating into the Atmospheric Window.

[Piotrsko]

Originally Posted by freebeard

The paint is re-radiating into the Atmospheric Window.

Not sure you can prove that. It is radiating somewhere

[aerohead]

http://https://www.google.com/search...QxsUjvcJt5gWBM

Originally Posted by Xist

Does this video just describe UV coating glass with extra steps? It does apply to other materials, which is wildly different, but for glass, it just sounds like a more complicated way to UV coat it.

Seems like it's about what an individual would experience when 'wearing' or 'inside' the technology.
UV flux would still intercept the material, but the amount of infrared radiated to the individual would be mitigated to some degree.
What's seldom mentioned is that, global warming increases evaporation, raises relative humidity, and the heat index, and it's the heat index that's killing people.
And simply lowering the dry-bulb temperature of humid air actually 'INCREASES' the relative humidity, as the air moves closer to 'saturation', making it it even more uncomfortable or deadly.
Only refrigeration can take the moist air below dewpoint, and condense out enough water vapor to bring the enthalpy of the air to within the limits of human comfort.
Any air conditioning contractor can provide a 'psychrometric' chart, used to engineer heating and cooling systems. They're available online as well.

[freebeard]

Only refrigeration can take the moist air below dewpoint, and condense out enough water vapor to bring the enthalpy of the air to within the limits of human comfort.

en.wikipedia.org/wiki/Thermal_wheel#Desiccant_wheel

A desiccant wheel is very similar to a thermal wheel, but with a coating applied for the sole purpose of dehumidifying, or "drying", the air stream. The desiccant is normally silica gel. As the wheel turns, the desiccant passes alternately through the incoming air, where the moisture is adsorbed, and through a “regenerating” zone, where the desiccant is dried and the moisture expelled. The wheel continues to rotate, and the adsorbent process is repeated.

I will qualify my "No" having re-viewed the video. While it does eventually get to the 'reverse greenhouse effect at ?t=303 after an interesting animation, at ?t=606 there is a paper on infusing silk with aluminum oxide and tetrabutyl titanate that acts in the UV range. And shows a 10 degree advantage over cotton. Surprising to me since UV is only 3 to 5% of the total

[aerohead]

Originally Posted by freebeard

en.wikipedia.org/wiki/Thermal_wheel#Desiccant_wheel


I will qualify my "No" having re-viewed the video. While it does eventually get to the 'reverse greenhouse effect at ?t=303 after an interesting animation, at ?t=606 there is a paper on infusing silk with aluminum oxide and tetrabutyl titanate that acts in the UV range. And shows a 10 degree advantage over cotton. Surprising to me since UV is only 3 to 5% of the total

Some of our clients used the desiccant technology, at a terrific energy penalty compared to refrigerated air.
It's kinda like that gas-fired, 500-degree F heat required to regenerate the activated charcoal used to remove VOCs from water at the waste treatment facility.

[freebeard]

Still waiting on Tesla's home air conditioner that produces potable water.