I found 5 solar panels (hydronic) for sale in CO for $100 each. All the tag says is Olinsolar model # II. I couldn't find any info doing a search. Probably out of business. Here's the link:
They have 1/2" inlet and outlet. They guy says they don't use the conventional manifold/riser design nor are they serpentine. He says its a kind of 'spider-web' pattern inside. He's going to scrap them out on Monday. Says he can get $90 each for the copper. The design I was thinking about basically has 3/4" manifolds with 1/2" risers, 6' high x 20' long with about 35 risers. The cost of materials to build it would be a little more than what the Olin panels are for the same square feet. From where I live it would cost $200 in gas and 10 hours to go get 'em and if I build 'em and something goes wrong then I have no one to blame but myself.
Interesting, but I would skip these for being too far away -- by using the time to build your own instead, you get a lot more out of learning the design. If you do a nice job with your own construction, you could well have 4 revisions and teach 30 people, helping your own use and that of others...
If all you will lose is 10 bucks, then it is worth a chance. The aluminum frame is also worth scrap price and the solar glass will one day be priceless. I found 6 old ones that are shot, but plan to use the glass in a solar greenhouse application. When you get them pressure test them with a air compressor. I would tend to think if they hold 25 pounds of pressure for a day they are good to go.
On average, one square foot of collector will heat one gallon of water to 120 degrees - from 56 degrees - in 6 hours of direct sunlight. The capability of older wore models do dimish over time, but I know of some 30+ years old that are still doing a good enough job.
It said in the add that they were pressure tested to 60psi for 15 minutes. I guess he does this a lot - find old ones at auctions and sells them on CL. From the picture in the add, the glass looks somewhat opaque. I think I may pass on these and build my own - a small one to start with to heat my 8x12 shed.
Yeah, the better solar thermal glass is opaque. It also has a roughness to it that helps to capture the radiation. I spent a little time researching and the link is the best explanation I found. Olin may have been using a product similar to Astra. Also, this glass can really take an impact. Long aga a teacher I had told me they can take a hammer dropped on them from a rooftop. Its really good stuff. Not that I am trying to change your mind!
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