Solar active air heater featuring fifty two square feet of collector space. Home made, on the cheep with srcap and salvaged items!
        After a lot of reading an the decision to build an active solar air panel, the next obvious step was the design, and construction materials. Since this is my first, I did not want to have a lot invested in the project, and also I did not want to cut any holes in the house or siding! So the design height and width was determined by the material at hand. The basic design guidelines for the panel, came from The Complete Handbook of Solar Air Systems . The size of the panel is 16 feet long and 45 inches tall, with a collector space of 14 feet by 45 inches.  Being that I did not want to cut any holes in the house, I built a 12 inch plenum on each side that cover the basement windows. Two six inch ducts feed the inlet and outlet from the windows. You can see some of the details in the photos.
        This was built from scrap materials, except for the insulation, screws and caulking, and paint.
        Materials used;
  1. 10 ft sections of metal wall stud plate normally used for constructing walls in commercial buildings.
  2. Metal suspended ceiling wall track.
  3. 9 inch aluminum siding removed from a house being torn down.
  4. The windows were removed from a sun porch, another house that was being torn down.
  5. Dow Tuff-R foil backed insulation.
  6. Thurmalox solar collector coating was used on the collector plate area.
        The framing was built using the wall stud plate. The ceiling wall track was used to support the sides and center of the collector plates which were made from the aluminum siding. Also the outside is covered with the aluminum siding. I plan to add another piece to the top to deflect and keep water and snow from accumulating on the top of the unit. You gotta love Ollie's, my favorite closeout store. They got a load of caulking in made by Tremco, at $0.99 a tube, could not pass it up. I used Tremco Specrtra I, a black silicon based construction sealant, and Tremco black butyl rubber construction sealant. I use Tremco products at work, it is great stuff. It takes a lot longer to cure, but it remains much more pliable as the temperature shifts.
        The design is in which the air passes behind the collector plate, with a 1 inch air space. I split it into an upper an lower chamber, with a channel between the chambers made from ceiling wall track, and it also serves as a center support for the collector plates. You can see the first piece of aluminum attached on the left side of the first photo above. Using calculations from  The Complete Handbook of Solar Air Systems, it was easy to calculate the need CFM for the blower. But, being that the design was not exact, I want to experiment. I purchased a larger CFM blower that was required, and a blower speed control on Ebay so I could experiment this winter with different fan speeds.
        Here you can see the inside of the inlet air plenum. The six inch inlet and also air diverters to split the air between the upper and lower chambers. At the top corner of the plenum is an air diverter to ease the air around the corner. On the hot side in the corner air diverter I mounted the thermostat switch, which turns on at 110 degrees, and off at 90 degrees cycling the blower.
        The panel is sitting on three 1/4" steel brackets towards the middle, and a piece of angle iron at the extreme left and right ends. The top and sides are attached to the house with four aluminum brackets and screws. also I purchased a few tubes of DAP clear silicone paintable caulking to use where the panel meets the house. The panel frame was mounted first, then the windows, then the aluminum on the outside.
        Here is the air inlet and outlet duct work coming through the two basement windows.
There is a spring loaded damper on the inlet connection. Notice the 24v motorized damper on the outlet, which opens when the collector reaches 110 degrees and the fans turn on. I picked it up on ebay for $25.00. If the air output from the collector is adequate this winter, I plan to connect it to my furnace plenum which is two feet away. My wood burner is also connected to the plenum, and heats the house when operating.
        The fans are in the left photo above. My calculated CFM requirements are 130. Originally I had a furnace flue vent blower connected. It was rated at more CFM that I needed, but I figured I'd try a motor speed control and dial it in to the temperature I wanted. I read where a higher CFM air flow, with a lower temp will deliver mote total BTU's per hour that of a lower CFM blower. I wasn't' t satisfied with how the blower worked with the speed control, since a shaded pole blower will tend to overheat at low speed and end up not being very efficient. So I used two 120mm, muffin fans rated at 100 CFM each. Muffin fans do not like higher static pressures, they tend to slow down a bit, that is why I used two fans. Even so, the output temperature attained is what I wanted, around 115 degrees. The photo above on the right shows the output around noon time with inlet temp of 70 degrees. So it will be interesting to see what kind of temps I get this winter, especially when the sun is at a lower angle which will be better for the collector.

        The control panel is in the center photo above. It was part of an old refrigerant monitoring system from where I work. Why so elaborate? I plan to use it to also control my next project, a solar hot water pre-heater. It has a nice 5vdc power supply which control the relay bank at the bottom. Notice also the 24vac transformer on the lower right that powers the damper.
The wiring is pretty simple. The temp sensor in the collector energizes two relays that operate the damper, and the fan. When the collector temp lowers to 90 degrees the fans will turn off and the damper will close.
What's The Plan?