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Re: A wall warmer with a fan



Scott Martin <effeng@io.org> wrote:

>There is a product on the market called a "Solarwall." Made by Conserval...
>It consists of a black metal cladding with small holes in it...

Right. Thin black painted aluminum with about 2% of the area covered with
1/32" holes. I've talked with them and looked at their literature. This is
usually used in warehouses, etc, as the exterior skin, with suction from a
blower bringing air into the wall transversely, with no glazing! Since it
warms outside air, it is not too useful for houses. It attains an impressive
solar collection efficiency of 80%, and they say that glazing would reduce
that by at least 20%, but with some glazing, you could make indoor air hotter,
instead of just heating outdoor air from, say 32F to 40F. I think NREL is
doing some closed system testing, to evaluate this product for heating indoor
air, with glazing. That will probably work fine, BUT...

It costs $4/ft^2, vs greenhouse shadecloth at 13 cents/ft^2. Perhaps
shadecloth won't be as efficient as a transverse airflow solar absorber,
but it probably still makes more sense, at that price.

Nick


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