|
|
re: polyiso vs styrofoam
19 nov 2005
anthony matonak wrote:
>... i've heard reports that there were other issues with
>the beadwall system. for instance, the foam beads would
>break down over time.
not exactly. they tended to clump if never cycled.
iirc, cycling once a month would fix that.
>> "replacement foam insulation" (filling the space between two glazings
>> with soap bubble foam at night) seems more practical.
>
>... i question it's usefullness in a house. for instance, how clear and
>streak free are the windows when the foam goes away?
moreso than my $500 500 ft^2 cloudy plastic film sunspace :-)
>how do you insure that the window cavities are sealed well enough that
>they don't ever leak in some hard to detect fashion and cause damage to
>the structure?
i'd probably make the "windows" with 2 layers of 0.020" clear polycarbonate
from a 48" roll, over plastic 2x4s, with lots of silicone caulk.
>... how do you design the windows so that they can open?
you don't. a few plain windows might do that.
>how about this for a possible solution. there are double pane windows
>being sold now that have window shades or blinds inbetween the panes.
>mostly, this means that they never get dusty and you won't find the
>cat has hung himself from them. air is a pretty good insulator except
>when there is some kind of circulation going on.
even tiny circulations.
>a cellular shade could be produced using thin mylar or paper such that
>it folds up into a small space at the top or bottom of the window cavity
>and yet can unfold to fill the entire space with small air-filled pockets.
it could be...
>one or more layers of aluminum coatings could be added as well to
>help cut down on radiant loss.
good idea. scheme 18.7 on page 168 of bill shurcliff's 1980 brick house book
"thermal shutters and shades" describes 5 sheets of metallized mylar with
springy spacers that unfold when it's rolled down. scheme 18.8 on page 170
describes an interesting self-inflating mylar shade. alas, these are no longer
being made. perhaps they can be recreated with an iron or a $118 -rs1 hot
roller for plastic film seam-sealing from hillas at (800) 952 7274.
symphony "energy track" shades with tracks on each side to reduce air leaks
are fairly expensive and low performing. they (877) 966-3689 say their room
darkening shade has a r-value of 3.2, when used with an r1.8 window :-) this
increases to r4.8 with side tracks. a 3'x6' shade costs $170 with the tracks.
tiny cold soap bubbles can have the same r-value as fiberglass. a 6" window
might transmit 80% of the sun during the day and become an r20 wall at night.
nick
|
|
