On 1/10/2010 12:58 PM, Morris Dovey wrote:
On 1/10/2010 9:10 AM, aeroloose wrote:

OK, one more aluminum idea, then I'll quit ...

Serious response to lighthearted comment: Solar heating technology has
advanced to the point where a conventionally-built structure can be
(_has_ _been_) 100% solar heated through several winters in an area
where this morning's temperature was below 0°F. Ten years ago, not even
I believed it could be done - and even (especially?) I know it can be
done better still - hence this discussion.

Leaving aside all AGW possibilities (because I have no first hand
knowledge of the subject) and all political crappola, there are obvious
real and significant financial and social benefits to be had from a
technology that keeps people warm and comfortable without the need for
them to pay and pay and pay.

Please don't quit. :-|


Appreciate the encouragement ... sometimes it's hard to
judge how folks will respond in newsgroups these days ...
it's a risk when you're not a regular.

To minimize the conductivity issue, how about an aluminum frame (L
channel) that would "clad" the box on two sides? This should get the
aluminum out of the heat-path. You could add threaded bosses to the
underside of the channel, counter-bore the wood frame, and through-bolt
the aluminum frame to the wood frame with plastic bolts.

You're not actually all that far from the current design - except that
the L doesn't extend all the way from the outermost edge to the
structure surface. It's actually a 1/8 x 3/4 x 3/4 aluminum angle - used
to secure the glazing, shield the glazing-to-box sealant from UV, and
hide the glazing's edge.

If that angle were extended inward past the structure skin, there would
be a problem with removing the glazing for cleanout, and with replacing
the glazing in the (unlikely) event of damage. I think a two-part
solution is appropriate, so I'm after just the flat side portion that
can extend from under the angle to a point inside the structure wall.

So now I'm like a dog with a bone . How about we keep the
idea of the cladding on all four walls, let the cladding
extend across the top to the edge (holding the glazing in
place), and let it get enclosed in the supporting structure
at the bottom of the box (non-removable). BUT, we leave one
upper edge in the angle format (the angle you have now) so
that edge could be removed and the glazing slid out (think a
poster frame with one edge removed). Add some gasket design
work, and you might avoid caulking & adhesives there, too.

As suggested, any of a number of materials might be used for that
protective extension, and even though aluminum is easy to work, I have
reservations about its longevity.

I think the plasma or HCA treatments will address that
concern pretty well (ref. General Magnaplate, Duralectra).
Plus, they have lots of colors ...


This also avoids the lamination issues others have noted, as there isn't
a need for a bonding mechanism between the wood / cladding anymore.

Thus far I've carefully avoided any through penetration of the walls.
I'll need to think about this a bit. Much will depend on the reliability
and durability of available adhesives.

.... and a final thought to eliminate the penetrations. Keep
the cladding full-length as above, but add tabs at the lower
edge to bend over the wood frame and fasten the cladding in
place (beating the poster frame analogy to death, think of
those bend-down tabs that hold the cardboard backing in
place). Then put a fastener through the tab to lock it. I
think the heat-loss here would be small, and could be
further reduced with an insulating layer along the tabbed edge.

Aero