Modified Trombe Wall

An alternative to the solar greenhouse is the Trombe Wall that gathers almost as much heat and takes up less space. As winter approaches in the northern hemisphere sunlight striking a vertical surface is more direct. This is why a Trombe Wall actually gets hotter in the winter than in the summer. Flaps not shown in this picture are still needed to prevent heat loss at night. 

A modified Trombe Wall is fairly easy to build with common construction materials such as plywood and 1x4's. Just frame out the box as shown in the picture. This Trombe Wall is made with a 4x8 sheet of quarter inch plywood and two 1x4x8's. The absorber plate is corrugated metal. Notice the top and bottom vents allow cold room air to rise and heat up inside. The back of the Trombe Wall is of course painted black to change visible sunlight into heat. Don't forget the glazing. The best glazing for a project like this is Kalwall available from:
www.solar-components.com .  A 4x8 sheet will run you about $100. Clear plastic works, but not as well. 
To transform a passive solar greenhouse or passive Trombe Wall into an active system simply replace the top or bottom flaps with fans. The increase in heat transfer efficiency more than compensates for the power used to run the fans.

If you decide to build and test the modified Trombe Wall concept please share your experimental results with us through the Bulletin Board under TROMBE WALL.