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re: "sixty feet under"
8 dec 2005
travis jordan wrote:
>"what happens is through cooking and the opening and closing of windows,
>the interior adjusts to a temperature that is comfortable to you,"
>
>yeah, sure. uh huh.
why not, with enough insulation? the deep ground temp in seattle is 52 f
and an average house uses 800 kwh/mo (3800 btu/h) of electricity, so
a 2300 ft^2 house with 6000 ft^2 of exterior surface could stay 70 f if
3800btu/h = (70f-52f)6000ft^2/rv, with rv = 28 ft^2-f-h/btu walls.
the yearly average sun on the ground is 1050 btu/ft^2 per day, and 820 falls
on a south wall, so a house with lots of insulation and thermal mass could
stay 70 f with no indoor electrical usage with a ft^2 of r2 skylights with
80% solar transmission if 24h(70-52)((6000-a)/rv+a/2) = 0.8x1050a, ie a
= 6000/(1+1.44rv) = 201 ft^2 with r20 walls or 100 ft^2 with r40 walls.
with a long time constant, the indoor temp changes slowly, so there's no need
for a thermostat :-) my neighbor raised the temp of his pa underground solar
house from 70 to 72 f every year by closing windows over 2 weeks in november.
why are the homeowners only shooting for 55-60 f and how can the house be
"sixty feet under" 50 tons of soil?
john hait's 1983 "passive annual heat storage" and mike oehler's
"$50 and up underground house" books are related...
nick
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