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Save energy with smart windows

17 February 2010

Smart windows can regulate the amount of light coming through.

Do you have a battery layer in your window that regulates the amount of light coming through? You don’t? But in the future this may be possible. Researchers at Uppsala University have developed a battery foil that comes in rolls.

Determining how much sunlight to let in a room is not just a matter of comfort. It is also possible to save lots of energy when sun-warmed rooms don’t have to be cooled.

“Lots of energy is used to ventilate warm air out. Not only in warm countries, but also in Sweden, where many commercial premises need to be cooled much of the year,” says Claes-Göran Granqvist, who is a professor of solid-state physics at the Department of Engineering sciences.

He has taken part in the creation of so-called electrochrome material in rolls, which is unique in the world.  The material consists of thin surface films with three layers that can be applied to a pane of glass: an anode, a cathode, and an adhesive in between that functions as an electrolyte, meaning that this can be likened to a thin battery surface. The battery can either be connected to a presence sensor or be controlled remotely.

“This provides great flexibility because people can regulate the admission of light and heat themselves. In many cases it can make energy-consuming air conditioning superfluous,” says Claes-Göran Granqvist.

Thus far the material is available only in prototypes, but Claes-Göran Granqvist says the technology is now being developed on a large scale. There are multiple areas of application. For instance, hot cars in the summer may soon be a thing of the past when the windows are tinted. There are already certain helmets available that use the same material.

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Solar energy materials