Scullvine t1_iv87j6v wrote
Reply to comment by bigdish101 in Researchers designed a transparent window coating that could lower the temperature inside buildings, without expending a single watt of energy. This cooler may lead to an annual energy saving of up to 86.3 MJ/m² or 24 kWh/m² in hot climates by mossadnik
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
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