re: synergetics coordinates
1 dec 2001
joe s moore wrote:
>if properly designed, any dome would be self-cooling; see
we've heard this story over and over, but where are the numbers?
i don't think there's anything magical about dome cooling. we might
think of one as a chimney with height h feet and vent area a ft^2
at the top and bottom and indoor-outdoor temp diff t (f) and airflow
cfm = 16.6asqrt(hdt) and heatflow q = cfmdt btu/h. adding a shape
like a cooling tower on top vs an sharp-edged hole might speed up
the air a little, but the basic idea, energy-wise, is to turn the
heat power inside into a) warmer air and b) moving air, and that old
empirical chimney formula says how the power divides between them.
for a small example, we might put a house using 600 kwh/mo (2843 btu/h)
of electricity under a 50' dome with a 4 ft^2 hole at the top and some
holes at the bottom totaling 4 ft^2... 2843 = 16.6(4)sqrt(25)dt^1.5 makes
dt = 4.2 f, ie it would be about 94.2 f inside on a 90 f night. if it's
transparent, with say, 80% solar transmittance and 1963 ft^2 of surface
facing full sun, we need to add about 0.8(1963)250 = 393k btu/h, which
raises the temp diff to 112 f, so it becomes 202 f inside on a 90 f day.
>> what's the power consumption of nyc? how would you cool it?
it's a pretty good heat sink now, with all those pointy buildings.