Sunlight that enters office- or appartments buildings through large windows is an important source of heat, which has to be matched with powerful air-conditioning systems to keep the temperature acceptable. This has a negative impact on the financial and ecological costs related to large windows. Windows with metallic coatings, external sun screens, blinds and curtains are either static solutions or require mechanical systems that are prone to failure.

We propose a window that can switch electrically between a transparent state and a scattering state. In the scattering state the visible and infra-red incident light of the sun is mostly reflected, which keeps the building cool. In the transparent state the window allows to enjoy the view as in a conventional window.

One aim of the project is to realize an A4 size prototype to demonstrate fast and efficient switching between the two states. A second aim is to evaluate the manufacturability of a large window with an area in the order of one square meter.