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re: my solar/fire drum collectors
21 oct 2005
wrote:
>>warm air rises... i tucked 60 4"x10' thinwall pvc pipes between 2x6 joists
>>on 16" centers in my neighbor's basement ceiling...
...3 per joist cavity.
>i could maybe do that in just the laundry room and heat storage closet
>... i could get maybe 21 in that way.
that's all?
>i'd think if the space under the work bench is enclosed, you would
>[not?] lose much heat from it except when the fan blows air through it.
>i guess i'll lose some to the slab, but that will be ok i'm guessing
>since i'll need to have some heat anytime the sun is down and the fire
>is out. but it would be better to have the extra space.
sure. and that mass would only swing with the room temp, unless you had
a fan with a duct to and from an enclosure around the stove.
>>you can also save wood by letting the house be cooler at night.
>
>brrrrr :) i'm good down to about 64, and don't mind wearing a
>stocking cap and a sweater.
the room might not reach 64 with high-e ceiling mass warmer than 70.
>>an 8' 50 cube with r20 insulation and 30 f air outside only needs
>>(50f-30f)5x8'x8'/r20 = 320 btu/h at night, excluding the ceiling.
>>excluding the occupant, a t (f) ceiling can provide this heat if
>>0.1714x10^-8e((t+460)^4-(50+460)^4)64ft^2 = 320, where the ceiling
>>emissivity e can vary from 0 (a perfect ir mirror) to 1 (drywall,
>>plain paint, and so on.) this makes t = (510^4+2.92x10^9/e)^0.25-460
>>(push the square root button twice), so e = 1 makes t = 55.4 f, and
>>we can't store much heat up there... e = 0.1 makes 97.9. much better.
>
>...you mean emissivity above the ceiling heat storage...?
no. below it, to reduce radiation that heats the lower part of the room.
>anyway, i squeezed r30 fiber glass batts between my 2x8 joists. they
>billow out a little. i ran 2x4's under perpendicular to the joists
>and attached gold faced mylar (54" wide) under that as a vapor barrier
>and reflector for light and heat. that gives me an air gap between
>the batts and the mylar, which seemed like a good idea at the time.
sounds like a good idea, if you mostly live in the basement.
>thanks for the tips nick. did you get all your tomatoes harvested by
>now i guess?
mostly. we are starting to clean out the greenhouses now.
nick
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