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Anybody build a solar air heater?

Post in 'The Green Room' started by Corey, Oct 30, 2007.

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  1. Cath

    Cath Feeling the Heat

    Joined:
    Jul 31, 2007
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    rhetoric,
    This kind of reminds me of the Chevy Nova I got for free with the purchase of a $3000.00 key chain.

    Do you have any idea how much the mylar coated foam costs? Does this material go on the "inside" or "outside" of the window?

    One of the pictures seems to show that the black material (mylar?) is torn, is this a trick of the light? If so, do you think you would get a better result if the material were intact?

    Do you have a side view of the window? Is there any reason you couldn't simply cut the celotex mylar coated foam to fit an existing window? That would enable you to cut it to fit and pop it in and out and switch it from one window to the next as the sun moves; or perhaps even rig it to tilt for maximum light absorption.

    If the coated foam is prohibitively expensive do you think you could simply spray paint a cheaper piece of foam with flat black paint?

    I'm still a little foggy on how the heat would actually enter the room. I'm also torn on whether the foam would block the heat from the room or simply turn it into radiant, time released, heat. I'm guessing that would depend on whether the mylar coated foam is on the inside or outside of the window. I would think it would need to be inside the window, and therefore inside the room, for meaningful heat transfer.

    DH has been thinking about doing a free standing solar collector made of aluminum cans and "piping" it through a basement window.

    We did some looking around on the internet and have seen at least one aluminum can version designed to be hung from a heavy curtain rod in front of the window (inside the house). Apparently the Wife Approval Factor (WAF) there involved not bending the curtain rod.

    I suspect that the continued rise in heating costs will challenge the usual WAF criterion.

    ~Cath

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  2. slim62

    slim62 New Member

    Joined:
    Nov 27, 2007
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    Loc:
    west texas
    They are really simple and fun to construct as long as you 'dont over complicate' your design . If you go to www.altenergystore.com and go to customer gallery pics for Toni Reese , you will better see how the air exits and enters the heater. They work by convection , hot air rises and comes out of the heater at the top at a pretty good clip .at the same time it is sucked off the floor through the lower hole to be heated as it passes through the channels and rises . The 3 we are building for the garage , we are building with the cans 'instead' of our aluminum foil coverd wooden channels . It should heat up even faster.
    I suppose you could use your window through some trial and error. but we built a flat box and lined it with insolation board then aluminum foil then painted back . then attached it to exterior wall on south side of trailer . If you have an e-mail i can send you step by step pics .The one we built for the trailer cost us for the dryer eghaust hose only , we had rest of the junk laying around . (sadly)
  3. slim62

    slim62 New Member

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    not our heater but a good example

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  4. slim62

    slim62 New Member

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    west texas
    paint black with heat paint , add glass

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  5. slim62

    slim62 New Member

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    interior view

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  6. rhetoric

    rhetoric Member

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    Loc:
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    The foam is 7-15 bucks a sheet at Dome Teapot. It comes in varying thicknesses. This chunk was just a sheet out in the shed. I'd go much thicker if I were actually building one for my home (this was just an experiment). You need the insulation value on a real one since the device sits outside. The mylar is torn on mine, but on the back where it doesn't matter. The surface I painted black (exposed to the sun) was intact. As I understand it, a metal surface is much better than non-metal so the mylar is nice in that regard. And chrome painted black is best, I was told -- but don't know why, but mylar is cheap. I suppose you could put foil or something, but this foam is so cheap and the mylar is bonded -- you might as well use it.

    I haven't yet figured ou the physics. Some say sun through the window is sun through the window -- others say dark thermal mass inside the window gathers more heat. I suppose I could test it with an unpainted piece of mylar. Anyway, just putting the mylar in your window might not do much except block the view. I don't know, but the box in effect gives you more windows for "passive solar." You now have windows on the siding or up against the house that grab solar energy that would otherwise get absorbed into the ground or whatever. Around here, there are people who have big black glass collectors all on the southern exposure, but they look fancy and expensive. I'm a tightwad.

    Two options. The two hole method you see in the other pics or the window box method. I'd add a second chamber on my box w/ a split opening that fits into an open window (about 6 inches or so). Shut the window on the box, heated air rises in through the windo and into the room -- the cold air is then sucked into the box, flows down the heater, gets heated and rises.

    The can method is nice because it's cheap metal, but you still have to build an insulated box, so you might as well use the mylar. The cans also slow the air for additional heating, but you can do that with boards like the ones in the photos.

    Hope this helps.

    I noticed I repeated myself alot in this repeated myself alot in this thread, but I'm too tired to fix it. If I still lived in DC I could get a job with the Department of Redundancy Department.
  7. slim62

    slim62 New Member

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    Loc:
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    The passive air heater we built for our guest house (very small trailer0, Finally got it downloaded , Heats to 'over warm' most of the time . works terrific!!!!

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  8. streeter69

    streeter69 New Member

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