The double-skin façade reduces heat losses in the winter and heat gain in the summer through optical control of sunlight. Within one floor height, the double-skin façade can be divided into three sections. The upper section is made of insulating glass with integrated prismatic panels which automatically adjusts itself as a function of the altitude of the sun. This panel has two functions: reflecting sunlight toward the outside and admitting daylight into the interior space. The vision window is made of clear insulating glass and is manually operated by the occupant during the daytime. The lower level window is automatically controlled to stay closed when solar and thermal insulation are desired. 

Reference 

Fontoynont, M. and European Commission Directorate-General XII Science Research and Development (1999). Daylight performance of buildings. London, James & James (Science Publishers) for the European Commission Directorate General XII for Science Research and Development.

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