Major Initial Influences
Gary Reysa's site builditsolar.com
was the source of almost all my information, ultimately, as that led to all my other main contacts as well.
Scott Davis, the proprietor of the Yahoo Group SimplySolar, created a self-standing 24 ft x 8 ft collector
in his backyard out of treated wood. I liked the look of it. Scott used pex-aluminum-pex tubing in a sepentine pattern in his collector, and I would use copper and aluminum for their greater heat harvesting power, but I easily adapted his collector to my use. Scott's approach is a lot easier, but I'm hoping my design will put out some additional much-needed BTUs in winter.
I liked the work Gary had done with copper pipe and aluminum fins
. My collector would be slightly different from the ones Gary had built, but people agreed that the design should work fine.
I had a friend who built his own water storage tank for a solar system some years ago, but I ended up following Gary's design
in most respects for my tank.
So that's the basic pedigree. I poured over as many details of different designs as I could to flesh out the fine points of my own design. Here's my design in a nutshell:
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- 24 ft x 8 ft collector, ground mounted, made of treated wood, glazed with 8mm twinwall polycarbonate greenhouse panels
- Six 4 ft x 8 ft (approx) copper arrays, with 1/2" risers and 3/4" manifolds top and bottom, using aluminum as heat-gathering fins
- The copper arrays are deployed as two mirror-image sets of three, sloping toward the center. The supply water comes in the center bottom, splits left and right, and the returns come from the outer top corners of each set of arrays, joined at the bottom center.
- This is an open drainback system, with everything sloped from the collector to the tank. Water is the fluid, not glycol, and it all drains back to the tank when the pump turns off - nothing left to freeze.
- Well-insulated CPVC in a shallow trench from the collector to the basement, where the tank resides. Here I am assembling the insulated pipe runs on the ground:
- Plywood-built tank lined with EPDM, highly insulated, inside dimensions 83" x 24.5" x 33" deep, holding almost 300 gallons (following a common ratio of about 1.5 gallons per square foot of collector area). Two heat exchanger coils in the tank: 300 ft of 1" pex-al-pex for DHW, and 100 ft of 1/2" copper tubing for the pre-heat to the radiant floor system