HOW TO BUILD A DIY SOLAR AIR HEATER FROM OLD SODA CANS
The guy in the picture, Peter Rowan left his job as a self-described “corporate weenie”, and instead took up teaching, writing and converting a shed into a reclaimed writer’s studio. Because the studio was off-grid, electric space heating was not an option. So he set up a simple soda can space heater, using fans running off his solar panels to help channel the air.
Rowan is transparent about his own gaps in knowledge on the thermodynamics of solar space heating, and shares the ups and downs of his experiment. (Putting a panel that relies on convection on a relatively flat roof was probably not the smartest of ideas.) But once the installation was complete, he does feel like even on a cold, cloudy day he is getting a head start on heating the space compared to the ambient temperature outside.
Full instructions for building one of your own are detailed below and here also is a link to a video he shot on his phone which shows just how easy it is:
After you’ve seen and read what’s involved we’d love to hear your comments on how you think this basic design could be improved on.
HOW DOES IT WORK
The units are typically installed on the outside walls of houses, and of course, in a location that gets a lot of sun. The idea is to draw air from near the floor of any room in a home, and pass it through the heating panel, which contains several columns of cans.
The air is then returned to the same room near the ceiling. The cans are stacked and have large holes cut in both ends to allow the air to pass inside them while the outside of the cans is getting hot from the sun.
What you’ll need
240 aluminum cans.
3 – 8 ft. 2x4s.
4 ft. x 8 ft. x 1/2 in. sheet of plywood.
High temperature silicon.
4 ft. x 8 ft. sheet of Plexiglas or Lexan.
A can of heat-resistant flat black spray paint.
Drill Press with wide drill bits.
Optional Air Blower (consider a solar-powered unit).
How to build the solar panel
Construct a wooden frame out the the 2x4s, approx. 4 ft. wide x 8 ft. high x 3 1/2 in. deep. Next cut a piece of plywood this size and nail it to the back of the frame.
Drill a hole in the top center of the frame – this is where you’ll connect your outlet hose.
Drill a hole in the bottom of the frame – this is where your inlet hose will be connected.
Drill large holes in the tops and bottoms from all the cans except for 16 which will be on the bottom row. For those, drill the holes in the tops and sides. Caution! Aluminum cans are sharp – use heavy work gloves or other means to hold them in place as you cut the hols out.
Start placing your cans into the frame. Create 16 columns of 15 cans each. Stack them one at at time, sealing them together as you go along. Make sure the ones with side holes are on the bottom row. Allow the silicone sealant to cure.
Spray the cans and frame with the heat-resistant flat black paint.
Cover the frame with the sheet of Plexiglas or Lexan.
Cut holes in the side of the building that line up with holes in the top and bottom of the solar panel. Air will be drawn from the building through the lower hole, which should be just above floor level, and be returned through the upper hole.
Mount the completed panel on the exterior wall of the home. Alternatively, you might mount the panel in a separate frame that will allow it to be tilted more toward the sun for better exposure.
Install the blower at either the inlet or outlet. This is not essential, but will increase the efficiency of your solar heater.
This unit allows air to flow all around the cans as it moves through the panel. A more efficient design will force all the air through the inside of the cans. This will also avoid exposure of the air to the black paint.