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Old 03-11-10, 11:38 AM   #11
ksstathead
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But one can direct the heat within a room by adjusting the color of the floor/rug, because you want a warm, but not scalding, floor. You do not want to heat the ceiling ordinarily.

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Old 03-11-10, 02:33 PM   #12
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[QUOTE=Xringer;6085]"Alot of light and heat can get reflected back"

To be clear, I'm only talking about light that gets inside the house. Not the sun light reflected off the exterior glass.


What I'm thinking about is a normal room with a mix of dark and light objects inside.

Yes, I know that if everything in the room was painted black, it would not have much light lost back out the windows..

But, in a normal room it seems like (once inside) only a small amount of light bounces back outdoors.
My guess is about 10%.. I could be way off.

If it were a lot light coming out, looking into a window from the outdoors, would be almost like looking at the sun..
Like if your room was covered with mirrors, much of the light would just bounce back outdoors.

So, my thinking is, if you have 90% of your light bouncing inside the normal room,
isn't it going to get converted into heat? It can't just bounce around all day..




10% is way off, sorry to tell ya, if rays reflect off of something and hit something else, unless that particular item is good at absorbing heat and light energy well then is just a bigger dead end than it was before and semi-gloss paint keeps reflecting this energy away,
I would use dark materials in the day and white blinds(plastic at night)


glossy surfaces have their own heat absorption rates and what you're implying depending upon the rates of everything surrounding the one spot where the sun is hitting. surface vs surface is the big thing here and if you collect the heat at the bottom of a room via black it travels to the top and heats everything on its way, if its only reflected to the ceiling, it stays closer the the ceiling, not that it is, heat is not sun, heat does not bounce off of objects like light, you're confusing too many variables to be right about 10%.

true flat ultra black paint gets 120+ F in the sun and white semi gloss stays at about room temp(68)

Last edited by Solar; 05-07-10 at 01:20 PM..
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Old 03-11-10, 02:57 PM   #13
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When I said it was way off, I mean way too high.. I think the exiting light losses might be much less than 10%..

Here's an URL Understanding Energy-Efficient Windows - Fine Homebuilding Article

I skimmed it fast, but didn't see any number associated with light going backwards out the window..



Hey, those look like my Low-E windows!!
Just looking at that picture, it seems intuitive that what Sunlight comes in the window, stays inside..
Expect for the regular cold air leaks and low R-factor window leakage..
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Old 03-13-10, 09:20 AM   #14
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well take that 85-90%(maybe) and multiply it by the percentage of heat absorbant materials inside the room 60%= .6

50% heat retention.

a good test is touch the surface of whatever it is, and if it feels cool to the touch vs like wise other material then that does not absorb heat..

I had a whole bunch of metal (steel stuff) in my kitchen this winter and once I removed that it warmed up a little, because the metal absorbs cold and radiates it.

I had pure black carpets, and black window sills and raised the temp of that particular uninsulated room with bad windows(seal and pealed) from 56 degree in the 20 degree morning to 75 by 2pm

I had one window where half was white and half was black in the sun all day, and the temp reading for the white part was 71 degrees while the black portion was 74-75 constantly and thats wood..

you can find other materials that would work way better than this inside too, an aluminum window heater for example painted in black
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Old 03-13-10, 09:24 PM   #15
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I was just looking at some inside storm windows..
Larson Manufacturing

They look very easy to install and may even be available in Low-E glass..
I think maybe I'll call Lowes and see if they can order some for me.

With those on the inside, I would have 3 panes of glass and a lot lower heat losses.



Of course, there is always one more step..

Larson Gold Series storm windows are premium, top-of-the-line storm windows. - Larson Manufacturing

Exterior Storm windows! Dang! 4 panes of glass is three layers of trapped air insulation!!

That would really hold in the heat..
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Old 03-15-10, 01:56 PM   #16
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plexi glass and seal and peal on the outside of your windows works too..

my curtains tuck in is just something you can do on the cheap that works well..

caulking and tracking down air leaks is big
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Old 05-07-10, 12:12 PM   #17
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It sounds like the success to your method is coming from your curtains at night more than anything else. Heavy curtains that prevent a cooling "heat engine" from setting up on the glass surface is critical to retaining heat at night.

I agree with Xringer--unless you are transmitting heat or visible light back out of the window, what energy comes in effectively stays in, regardless of the color of the objects in the room.

This is why you want to increase your absorber/window area during the day with heat absorbing panels of some kind piped into the room during the day, with the same path blocked off during the night.

Incidentally, this out-transmission of energy is pretty much the largest heat loss in solar heating panels. Most of it occurs in the form of radiant heat loss right back out the glass/lens of the panel.
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Old 05-07-10, 12:54 PM   #18
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"Incidentally, this out-transmission of energy is pretty much the largest heat loss in solar heating panels.
Most of it occurs in the form of radiant heat loss right back out the glass/lens of the panel."

That's not really a big deal on solar hot-water systems, since the pumps turn off when the sun isn't out.
So, only the panel cools off, and not the hot-water in storage.

I remember my old hot-water panels warmed up super quick when the sun hit them in the morning.
I could hear the circulator pumps kick in pretty early in the morning.

~~~
IIRC, there was some kind of scheme to circulate coolant up to the cool
collectors at night, to capture some of that cold and pump it down into
the warmed-up house for cooling during warm summer nights.
Not sure how that would work around here..
(Actually, indoor heat would be pumped up to the roof).

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Old 05-07-10, 01:07 PM   #19
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Quote:
Originally Posted by kabutomushi View Post
It sounds like the success to your method is coming from your curtains at night more than anything else. Heavy curtains that prevent a cooling "heat engine" from setting up on the glass surface is critical to retaining heat at night.

I agree with Xringer--unless you are transmitting heat or visible light back out of the window, what energy comes in effectively stays in, regardless of the color of the objects in the room.

This is why you want to increase your absorber/window area during the day with heat absorbing panels of some kind piped into the room during the day, with the same path blocked off during the night.

Incidentally, this out-transmission of energy is pretty much the largest heat loss in solar heating panels. Most of it occurs in the form of radiant heat loss right back out the glass/lens of the panel.

that's exactly what I am doing(tucking it around shades at night) but dark blue works perfect for this, you must be able to see some of the sun come through the other side I think for this to work as it, from what I have read here, I assume this would allow excess solar radiation to stay inside the house, such as with this 2 millimeter thick sheet
this works extremely well better than spending a ton of money

by this, I mean this heats up your house instantly go buy a thermometer and surface temp reader... and $15 worth of sheets to start

exactly why pavement being black is causing global warming

Last edited by Solar; 05-07-10 at 01:14 PM..
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Old 05-07-10, 01:15 PM   #20
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400 thread bed sheets(dark blue) work too for this effect..

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