Shady windows

Scientists working at the Fraunhofer Institute for Building Physics in Germany, have devised an 'intelligent window' which can automatically modulate the amount of sunlight entering a room.

Just as sunglasses block light, the window's glass surface has a coating which is transparent at cool temperatures but becomes opaque when the temperature shoots up to a given level. In addition, the Institute has also developed a method to harness solar energy by warming the air on the glass facade of the building.