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re: ultrasound for bubble breaking?
4 mar 2003
sherwood botsford wrote:
>one of the ag permaculture groups has a discussion going on about
>insulating poly greenhouses with soap bubbles.
which one?
>i know of two experimental greenhouses that use this technology,
>one managing to be totally solar heated in ottawa, the other
>reporting 80% less fuel use in calgary.
bill sturm built a 12k ft^2 tomato greenhouse in calgary and measured
an 82% propane savings on alternate -20 f nights. as i recall, it had
no heat storage. all the sun shined on tomato leaves vs thermal mass
during the day. bob quist in toronto is applying bill's technique to
venlo glass greenhouses.
>one of the problems is getting rid of the bubbles quickly. you don't
>want to drop the curtain of bubbles before dawn...
it might be fine to waste a little heat that way.
>if you make a bubble solution that creates long lasting bubbles, your
>bubble generator doen't have to run much. but they take an hour or two
>to vanish in the morning.
that depends on the size and detergent concentration. heat, dryness, dust
and co2 are the enemies of bubbles. they might vanish quickly in sun.
>you can blow them out with the air used to inflate the greenhouse, but
>this wastes the solution.
you might just turn off the bubble generator and turn on the static
inflation fan at dawn.
nick
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