Solar panels are great, if you have the space then you can have as many as wish and place them anywhere as long as they get the sun most of the time, the draw back to using solar panels is the cost, they are very expensive, so much so that the savings may not pay for the installation for years to come, that is the downside of using solar power.

So the simplest solution would be to build your own solar panel, and it is not as hard as you may think. Because the materials required may be lying around the house, you will need, Soda Cans, Wooden Frame and a piece of Plexiglass.

Basically the cans are painted black, this helps absorb the heat, they have a hole drilled in the top and the bottom, these are then stacked on top of each other and assembled in lines to fit the frame, there will need to be an inlet and outlet port and the plexiglass fits over the top. What you have now is what looks like a piece of modern art in a glass frame, but in reality it is a home made solar panel.

Once assembled the cool air enters the solar panel through the inlet at the bottom and rises through the cans, by the time it reaches the outlet at the top, the air temperature has risen by 15 F.

This may seem to be a bit of weird contraption, but on a cold evening fifteen degrees can make a lot of difference even if it is just placed in the greenhouse to keep the plants warm!

Source  [HackNMod]