Thursday, July 8, 2010

Elisolar Combines Shading and Thermal Collection in One Attractive Package

Elisolar has an interesting new line of architectural shading structures that double as solar thermal collectors to heat water.

The shading louvers are aluminum.  Water to be heated is run through each of the shading louvers to pick up solar heat.  The water is supplied by PEX tubes that are concealed by the louver support frames.  The structure simultaneously provides shading for the building and heats water.

As indicated by the red areas in the diagram above, the shading structures can be used in a number of locations on a building.

Given that the "collectors" are unglazed and open to air circulation, a high collection efficiency should not be expected -- especially in cold climates.  But, the advantage of getting both shading and water heating out of one simple device may offset the expected low efficiency.  Elisolar is in the process of getting SRCC certification, so performance data should be available soon.

Anyway, this idea of combining shading and collection seems like a good one, and might take other forms -- any ideas?

If nothing else, it should keep overzealous Home Owner Associations at bay.

The Elisolar website... 
See the Experimental page for more mind stretching adventures in solar energy use :)


  1. Hello Gary,

    Awesome idea! I just had an idea reading your post about this system's low efficiency.

    The $1000 solar water heater system is angled to prevent overheating in summer. What if the insulation were removed (perhaps leaving one layer of transparent acrylic on top to protect it from the elemements / rain and then it was laid flat or slightly angled as the roof to a pergola / window shade.

    Perhaps the glazed part could then be added back in winter if the heating proved insufficient. A simple design for easily removable/attached insulation / glazing would probably be ideal, but anyway, this would be done only at the onset of each summer/winter, so it is not a big waste of time.

    On the plus side, such a design would make the usage of solar energy less 'obvious' to uninformed outsiders therefore reducing what many deem as OPSEC (operational security) issues :)

  2. Use it as a solar pool heater. In a hot climate - California, Arizona, Florida, etc. it would work beautifully, maybe all year. If the louvers were a primary coolant loop and you had a heat exchanger to heat the pool water, there'd be no worries about contaminating the pool water itself. If you ran pool water - think all manner of chemicals, chlorine, algicides, body oils, suntan lotion, grass, leaves, dirt, etc. - through a hot aluminum (highly reactive metal) solar collector. The system might not live very long.

    This kind of pool heating in cooler climates could be useful as well but freeze protection might be difficult to manage.

  3. It does seem like it opens a whole lot of possibilities for getting some solar heat from something that looks good and provides shade to boot.
    Horizontal collectors don't do very well in the winter (low sun), but even something that works three seasons would be a big plus. As mentioned, it might do pretty well in warm climates.

    On their site, they do show one arrangement for water heating with freeze protection, but maybe just draining it for the winter would be the simple thing to do.

    I do get emails from people who are very limited in what they can do by home owner associations -- this might be quite a good solution for them. I got one email from a person in NZ looking for a "stealth" solar heating scheme as getting permits do do your own system in NZ is apparently very tough -- this would be perfect for that situation :)



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