bigdish101 t1_iv79uxf wrote
Hasn't UV+IR blocking window tint been around for decades?
dalwen t1_iv7p1hv wrote
Yes, low-e coating. Designed to selectively transmit light in the visible spectrum but block/reflect IR and UV.
sunybunny420 t1_iv97455 wrote
Yeah this is confusing AF to me I’ve literally have some of this in my Amazon cart for like 2 years
It seems difficult to put on its essentially window tint. It’s shatter-resistant so it helps with flying objects and can make it more difficult for a break-in, and it deflects outside sounds. It’s cheap AF and comes in aqua, green, pink, amber, yellow, blue, black, and “silver” which gives an HD effect to the stuff outside. It’s easy on the eyes, and doesn’t look darker inside, the light’s just not harsh at all.
Reduces indoor temp by up to 12° Plenty of Amazon reviewers have test vids.
Should prob go through with that purchase soon it’s only like $16 but it seems difficult to adhere to the window. It’s v thin and you use soapy water and a credit card to squeege out the bubbles. People say it takes hours to do, so I’ve been procrastinating.
I guess these researchers didn’t try Google Shopping first lol
professorstrunk t1_iva0ghn wrote
Buy an extra wide squeegee and it’s a whole lot easier. Just keep wetting the surface of the film so the squeegee slides smoothly (Windex works fine).
Mr_Lucasifer t1_iva333d wrote
I think the difference is that the computer suggested using nanoparticles that are just above the short range of violet light, so blocking out UV light, and... I guess it figured out the correct range for IR. I'm confused about that part myself. Because IR is longer than red, and UV is shorter than violet.
In other words, if you layered a thickness of nano particles on glass in the exact range you wanted to block, visible light would still come through, but not the offending light you want to get rid of. A bit more sophisticated that tinting I think.
Scullvine t1_iv87j6v wrote
Yep, it's referred to as "curtains" when I use it though.
FearLeadsToAnger t1_iv8g818 wrote
Curtains are in the house, and are getting hot. You would need to hang curtains outside.
Scullvine t1_iv8qj93 wrote
They are, but due to scattering and refracting in a normal, unprotected room, less surface area is exposed that could absorb the heat. So curtains cool rooms pretty well. If you want to increase that, you could make reflective curtains I guess. But your neighbors wouldn't be happy, and it'd look weird.
fml87 t1_iv8udpl wrote
That doesn’t really make sense. Once the light has entered the space the energy is there. It doesn’t matter if that energy is spread over a large surface area or small, it’s the same total energy.
Curtains do make a difference because they do reflect light back out of the window even if they aren’t mirror-like.
HKei t1_iv9c0dh wrote
They also absorb and re-emit heat, some of which will go into the room, though some will go right back outside too.
DogsSureAreSwell t1_iva0al9 wrote
It matters if some of the delivered energy goes right back out the window.
Inside the room, heat the floor and you'll have convection and such pushing heat everywhere.
Inside a hot curtain even if it had 0 insulation value, half (ish) of the heat is going to head towards the room, and half (ish) is going to head back towards the window. The hotter the pocket between the window and the curtain, the more is going to head towards the room, the better the curtain is insulated, the more is trapped against the window to be transmitted back outside.
fml87 t1_ivak9lj wrote
In theory maybe but not in practice. The vast majority of the heat will be carried into the room via convective current. You’re also not going to get 50% heat transfer back out of an insulated window vs a sheet of fabric.
ConsultantFrog t1_iv9ynar wrote
You mean shutters?
FearLeadsToAnger t1_iv9zc2k wrote
Do I mean shutters? No.
Would shutters fair better outside than curtains? yes.
nool_ t1_iv8zsxe wrote
Yes bit are they transparent
steve626 t1_iv7xvje wrote
It's a layer of silver nano particles.
HardCounter t1_iv8p1ey wrote
Also, i'm no scientists but i've heard thermodynamics can't just be ignored. How is the temperature going down? All of the heat generating energy can't possibly be reflecting as well as taking some internal heat with it. Wouldn't a warmer temperature outside naturally lead to a warmer temperature inside given enough time?
EmperorArthur t1_iv8rfne wrote
What it's doing is stopping IR from going through the window and heating the room. The outside of the window instead absorbs it all and gets hot.
The reason that doesn't transfer all inside is first because can dissipate part of the heat on the outside surface. Second, the glass on the outside is separated from the glass on the inside. Which provides insulation.
Scullvine t1_iv8s45d wrote
Here's direct quote from the original published paper that acknowledged that and kinda makes it seem like the authors of OP's article hammed it up a bit:
"The device is tested in Phoenix for 37 h, and the chamber with the TRC can have a temperature up to 6.1 °C lower than that with the glass slide (Figure 4B and Figure S7). We note that both chambers have temperatures higher than ambient temperature because the transparency in the visible wavelength range of the TRC allows solar heating. In practice, TRC can work with other existing (e.g., air conditioning) or emerging cooling technologies (e.g., subambient radiative cooler) to reduce the overall cooling energy consumption of buildings."
nool_ t1_iv8zubq wrote
It's not going down its simpley never getting therr in the first place
HKei t1_iv9bvgw wrote
> Wouldn't a warmer temperature outside naturally lead to a warmer temperature inside given enough time?
sort of? It's a question of how much is "enough" time. Good insulation can keep a noticeable temperature difference without active cooling or heating for a very long time. In addition, temperatures outside don't stay at peak forever. For instance, if temperatures outside can hit peaks of 50°C but temperatures inside never go over 30°C that's huge win even if you'd like it a bit cooler still. With clever engineering you can reach much more extreme temperature differences using only passive cooling and insulation, but not without making sacrifices to aesthetics and on other fronts.
Lord_Blackthorn t1_iv8efc9 wrote
Yep, VO2 and VOx is a current popular material for "smart window" research.
GWJYonder t1_iv8s69v wrote
Yeah, I have them on my windows (it's really nice, except my cats don't get warm sunspots anymore). So this "breakthrough" may save 31% of power compared to "conventional" windows, but what is their improvement over similarly treated windows? Could just be 1% for all we know.
Beta_Soyboy_Cuck t1_ivasvtj wrote
The article seems to indicate it can also radiate heat in a wavelength where it can exit the atmosphere so it isn’t trapped (short v long wavelength radiation iirc). I’m not sure if the standard current tech does that.
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