[Strawbale] practical info on solar energy supply

[Jan Hollan]

Jan,

I would recommend you the world's best experts (in my guess) from
Arbeitsgemeinschaft ERNEUERBARE ENERGIE, who have started the Austrian
solar boom. They have some info on their http://www.aee.at -- mostly just
in German, of course. We in Czechia are learning from them.

The state-of-the art technology is a copper solar circuit using TiNOX
stripes (10cm broad, ultrasound-welded to a pipe, these are made directly
by http://www.tinox.de, or, more recently, absorber modules 1m broad,
welded elsewhere) and solar glass (low-iron one, having over 90 per cent
solar transmissivity) tables of 1m x 2m size. From such modules, any part
of a south facade or a roof can be made, replacing conventional surfaces
and giving negative heat losses through such a part of a building envelope
even over a frosty period.

I think they develop some programme even in Portugal, try to contact them.
The whole technology is described in detail in a German-written brochure.

For SB builders, assembling the collector surface at the site is the right
choice probably. Of course, wooden-frame collectors can be made ahead and
just attached to a wall or laid onto the rafters.
http://www.greenonetec.com is the largest producer of such units of
reasonable size (5 m2 and more). Just a bit far from Portugal...

In Czechia, we've been using an alternative low-tech solar circuit with
non-selective absorber. Unfortunately, I have no contemporary description
of it, even in Czech. The idea is, that the (6m long, usually) pipes make
a warp and the (1m long) aluminium sheets (20 cm wide, 0.63 mm thick) a
woof. The absorber is made as a tissue, 6 m2 is twined within some 20
minutes. We've been using Al pipes (10 cm apart, 10 mm diameter inside and
12 mm outside, but attaching them together on their ends is not entirely
easy and long-lasting. Cu pipes are an alternative, easy to solder up,
some circuits have been made this way.  The contact between the pipes and
the sheets is good enough due to elasticity of the sheets, and as it
remains dry, galvanic corrosion should be no problem. Standard
water-soluble dispersion primary paint is used to make it black.

I am sorry I cannot offer much more info now, I've been unable to pay
enough time to solar technology in the past years. There are some photos
on the Czech page http://www.veronica.cz/slunce.html (or directly
http://www.veronica.cz/centrum/solar/tinox/default.htm ).

SB-relevant, the 80cm insulation (+5cm mineral wool inside, for
temperatures over 95 degrees) of a large thermal storage cylinder
  http://www.veronica.cz/centrum/slama/f_tank/indextank.html
 (10 m3, obtained for free and used for the above-mentioned collector of
36 m2) we made in autumn may be of interest... English description is missing
again... The plaster has been made in a frosty weather already, so it's a
cement one.

> but for water heating you could try
> http://homepages.nsys.by/ecology/buidung/building.html A project by
> Yevgeny Shirokov, Chairman of Belarusian Division of International
> Academy of Ecology This project used a solar water heating design that
> cost $30 per house.

I'd be interested, but  the page doesn't work...

cheers, jenik (or jan, as well)


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