This post comes from a 2nd Green Revolution reader who forwarded us the idea. Originally from the Maine Solar Primer booklet 2nd Edition by Richard Komp with drawings by Caleb Crawford, the SunGrabber is a relatively easy way to capture some of the sun’s heat by attaching a home-made solar panel to an existing window. Also known as a “thermal siphon”, the idea in its simplest form works on the principal that hot air rises. The best way to understand the concept is to look at the drawing after the jump or at this URL at Build It Solar.
A home made solar collector that looks like a window is attached to and hung outside an existing window in your house. Insulation around the cracked window from which the device hangs out is essential. Once attached, the panel sits outside the window. Inside the panel is a divider that allows cool air from inside the house to sink down the underside of the solar collector. That cold air is heated by the sun, causing it to heat up and rise to the top side of the device and back into your house as warm air. Again, it’s a very simple concept but one that’s hard to explain in writing. The diagram does the idea the most justice.

- Justin Manger

[Image Credit]