Solar Presentation at the Iron Mountain High School on May 28, 2010. The two glazed panels were plumbed together, fed from a 5 gallon bucket. Water temps starting at each class were about 65 degrees (had to “cool the tank and panels after each class) and ended after 30 minutes during the presentation at 125-135 degrees. The kids were impressed!
Note the 3 different style panels for the presentation. The one on the left is an unglazed pool collector, the middle one is a PEX Tubing Panel with corrugated Polycarbonate glazing, and the far right panel is a 1/2″ copper tubing panel with tempered glass glazing (looks very nice with glass).
Two trailers set up for solar presentation at the Kingsford Middle School in April 2009. The two panels on the left are glazed panels. The four on the right are pool collectors destined for a swimming pool later this spring.
Solar Presentation at Kingsford Middle School in April of 2009. The two absorbers centered in this picture are PEX tubing collectors with corrugated polycarbonate glazing. The one on the left is a manifold design (vertical risers). The one on the right is a serpentine design. See Side by side test for comparisons.
Side by side test of manifold vs. serpentine design. A lot of valuable knowledge was gained from these tests. The serpentine brought the temps up quicker initially, but once hitting about 130 degrees, the manifold design passes the serpentine in performance. We suspect the manifold design extracts the heat faster from the panel than the serpentine, while the serpentine starts losing heat out the glazing once the temps in the collector get higher. If you are looking for the highest temp water, without regard to “quantity of heat”, the serpentine would probably be the best. An example; a run through the collector before entering your DHW heater where it will stagnate in the collector. The cold water hitting the panel also needs as much heat applied to it in ONE pass, as there is no storage tank to maximize efficiency normally seen from the manifold design. A recent builder from Florida purchasing absorber is designing a system this way. Obviously, this will not work in colder climates due to freezing. We’re anxious to see the finished project and results.
Testing the efficiency of my Pex “Manifold design” collector for a summer heating my hot tub. Results were really impressive. Two panels were found to be excessive, bringing hot tub temps up to 115 degrees. One panel would maintain tub temp, with high temps reaching about 108 degrees, lows never dropping below 102 degrees. When wanting to “hot tub” when the temp was over 104 degrees, I simply turned on a bypass switch, wired to the pump, and “cooled” the hot tub by circulating water through the collector at night. I could drop the temp to 104 within 30-45 minutes. Since the collector was “below hot tub water level”, and had no drain back ability, the test had to be discontinued once September night time temps were dropping below freezing.