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spaceracer
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Reflecting Sunlight

05/24/2012 12:52 AM

On reflecting sunlight with a flat mirror, is it possible to reflect the light without reflecting the heat?

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SolarEagle
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#1

Re: Reflecting Sunlight

05/24/2012 2:16 AM

You can diffuse the light thereby diffusing the heat...such as a glitter covered surface, or white sheet of material...You can selectively polarize the light removing longer wavelength reds, reducing heat...

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PWSlack
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Re: Reflecting Sunlight

05/24/2012 3:20 AM

Infra-red is a long-wave form of light. It can be absorbed by various substances that let the rest of the light spectrum pass through. Water and air are two media that might be applicable. So, yes, it is possible.

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spaceracer
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#3
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Re: Reflecting Sunlight

05/24/2012 4:15 AM

I have seen solar generators that have mirrors to concentrate sunlight on one spot, they must generate a lot of heat, and the light is reflected through air. But suppose you wanted to light a room in summer without adding heat to the room and without losing much light. Would it be possible to coat the mirror with something to keep from reflecting heat and still have a bright sunlight go through? Or maybe reflect the light through a pane of glass coated with (?)

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PWSlack
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#4
In reply to #3

Re: Reflecting Sunlight

05/24/2012 5:15 AM

So where does the heat go?

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Usbport
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#5

Re: Reflecting Sunlight

05/24/2012 7:20 AM

Yes, using a 'cold mirror' - a mirror that has a special coating that reflects visible light, but allows infrared (heat) radiation to pass through. The cold mirror coating can be put on glass, ceramic, or plastic film.

Here's a listing of cold mirrors available off-the-shelf from Edmund Optics. You can do an internet search for cold mirrors on plastic films -- like the films use in 'Low-E' windows.

http://www.edmundoptics.com/optics/optical-mirrors/specialty-mirrors/cold-mirrors/1900

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cuba_pete
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#6
In reply to #5

Re: Reflecting Sunlight

05/24/2012 3:41 PM

This is a damn near perfect answer...where is that button?
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Usbport
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#7
In reply to #6

Re: Reflecting Sunlight

05/25/2012 7:17 AM
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