Using solar energy to provide electricity and water heating is fairly well known by most people. What isn't as well know, is that you can also use the sun to provide heating and cooling.
Enter the Sun Lizard. The Sun Lizard uses the same process as a solar hot water system, however instead of water, the Sun Lizard heats air, and pumps the warmed air into a building using a solar-powered fan. The air is ducted to low level grilles in a room, where it heats the room and then rises back into the system through high level grilles. The air is then warmed by the sun again and continues the cycle. In summer, the fan is reversed and used as a heat extractor, pulling rising heat from a building and venting it outside.
A very simple and cost effective solution, easily incorporated into a new house or retro fitted to an existing one.