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re: thermal shutters
24 jan 2003
chrisachroisdk wrote:
>i think the main problem (which wasn't mentioned in the small print
>) was the overpressure while filling and partial vacuum (while
>emptying) which might blow out (or implode) the glass...
no.
>static was a further problem (exacerbated by the later choice of
>clear plastic sheeting) as the beads stuck to every surface (despite
>antistatic additives.
no.
>the polystyrene beads also slowly degraded to dust from being
>mechanically manipulated...
no.
beadwalls worked fine. the static problem was solved, and the beads lasted
a long time, if they were cycled once a week so the same surfaces were not
exposed to the sun for months. lots of beadwalls were installed. zomeworks
stopped making them to concentrate on other products like cool cells. the
main problems were that the beads required a lot of storage space when they
were not in the glazing cavity, and that each cavity needed its own vacuum
cleaner motor. with more than a few motors, the startups had to be sequenced
to avoid blowing fuses.
bubblewalls seem like a better alternative now. fill the space between two
glazings with air during the day and soap bubble foam at night. one shop-vac
can foam an entire 100' greenhouse, and during the day the bubbles collapse
to less than 1% of their nighttime volume as soapy water.
nick
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