most efficient collector for solar water heating - Page 4

 
You might consider a Hydronic system for heating. That way you could
combine solar and back up from propane if needed. Here's an idea to
get you started:
http://www.solarhaven.org/HPArticle.htm

Also, there are some ingenious mechanical trackers, I've heard of but
not yet seen specs. on. Here's one possible link to a water powered
tracker:
http://www.builditsolar.com/Projects/OddProjects/odd_project_refs.htm

  codechump@gmail.com wrote:

Thanks CC - the second link is a great resource.

Enjoy the holidays :-)

 
It didn't show in the picture, but I promiss you all the details, with
the schematics and an open source program, in a few weeks. A Chinese
factory is readying a product which will be sold online very soon,
probably for less then 10$ retail price. Of course including the
stepper motor and gears.

Solar space heating is much harder than water heating, because the
equipment is only used a few months in the year, and these are the
most difficult months of the year. I am afraid that my parabola is the
only solution that can really bring solar space heating cost down to
below that of fossil fuels, especially for high latitude regions.
Details of the economical analysis will come out with all the rest.

The economic criteria for space heating is that the collector should
not cost more than 250$/m^2 installed, and should remain very
efficient during the winter. Oh I've forgotten: I don't count on
government subsidies in the cost analysis.