Black Paint and Air Mixers
With the air delivery system installed, next is to finish the panel and screw on the glass. First paint the insides black. Use a special high-heat flat black. Black absorbs heat and does not reflect it back.
Once the paint dried, we made air mixers out of scrap pieces of aluminum. As the air flows through the panel, the ridges in the aluminum cause some turbulence for mixing. We stapled the aluminum air mixers to the sides of the baffles and the interior frame.
Apply weatherstripping to the top of the baffles and interior frame pieces (see above photos). Use a weatherstripping that can resist UV rays. Screw glass to the panel. In the case of our example, the glass simply set into the frame we earlier added. The glass should set tightly to the weatherstripping on the baffles and interior frame pieces so no air can pass over the top of the baffles. Carefully screw glass in place.
Obviously, this solar heating panel is designed to stay fastened to the home. During the months that heat isn’t needed, cover the glass and plug the air inlet and outlet.
A search of the internet will reveal other solar heating panel designs. Shown at the right is another popular design.
The biggest difference between their design and ours is the location of the black absorption plate. Their design uses a black corrugated aluminum absorption plate (difficult to find) and places it over the top of the baffles. The air moves through the baffles underneath the absorption plate. In our tests we found that when the absorption plate is placed over the baffles, it requires much more heat for the panel to work as all the heat has to be drawn from the absorption plate. In our design we retrieve heat both from the absorption plate and the heated air in front of the absorption plate.
One advantage to their design is that the air would not contact the glass and would rarely require cleaning.