re: keeping the house cooler
14 apr 1997
>> how about a roof pond,
>i was part of a group that retrofitted some surplus university buildings
>this way. i didn't like the design. it used a waterbed bag resting on a sheet
>of tin or aluminum over the roof joists, a strong frame, and hydraulically
i wonder where this project was, and where the insulation was.
perhaps this system was only for cooling.
>my suggestion was to replace the tin or aluminum with plexiglas or something
>similar and to color the water. this would have all but eliminated
>daylighting by electricity while still collecting some heat.
there could be lots of light even while absorbing most of the sun, since
direct sun is about 10k footcandles, 200 times stronger than a well-lit
(overlit?) 50 fc office. would colored light drive most people bananas?
>i also suggested that instead of big heavy insulated lid/reflected, that
>the bags be bunked--that is bag on top, supportive frame in middle, and bag
>on bottom. this way by pumping the water between bags you would have a great
>deal of control over the temperature.
i wonder about making the ceiling some sort of dark mesh, eg black aluminum
window screen or 80% black greenhouse shadecloth, under some large (8x8'?)
greenhouse polyethylene film pillows filled with tiny cold static soap bubbles
on a winter night (these bubbles can last for hours, and are almost as good as
fiberglass insulation) and larger, moving bubbles on a day with some sun.
filling horizontal pillows with bubbles might be easier than trying to make
bubbles uniformly fill poly pillows in curved plastic film greenhouse walls,
without leaks, which was tried with some success in arizona and new hampshire
in the 70s. these days, we can probably make better bubble sensors to keep the
pillows filled, and somehow recycle the air that comes out at the top, to
prevent the bubble solution from becoming dusty.
ceiling pillows 2' thick in the middle might contain 64 ft^3 of tiny bubbles
weighing about 20 pounds, and act as solar heat collectors during the day,
with a large thermal storage tank on/in the ground. the pillows might be under
a steep, fixed, monopitch roof sloping up to a translucent south wall, with
white paint or foil under the roof, and day/night modes reversed in summer.