Smart windows
New ideas in glass
Large windows in modern architecture offer more than aesthetics; they also capture light and heat, and thereby save energy. Large panes of glass carry disadvantages along with all their advantages. They limit the available surface on the walls and the sun brings too much heat into the rooms in summer.
The founder of Vestaxx is working on a solution for the first problem. So-called passive houses only need additional heating on a few cold days, so investment in a conventional heating system is hardly worthwhile. Electric supplementary heaters offer one alternative, and these are often installed as panel heaters on the walls for aesthetic reasons. However, this space is no longer available for other uses. Why not use the window surface for heating?
Vestaxx has developed a technology which works very efficiently and is nevertheless invisible. They apply a sheer, metal layer to the interior of the window pane which spreads heat when plugged into a power source. There is hardly any loss of heat to the outside and efficiency can reach up to 95 percent in modern three-pane windows. If the power comes from a solar source, the generation of heat remains CO2-neutral.
Modern buildings with glass façades now demand more energy for cooling than heating. The mechanical shading systems installed to combat this are costly and high-maintenance.
Working with the Adlershof annex of the Fraunhofer Institute for Applied Polymer Research (IAP), the Tilse Formglas GmbH invented a new, low-cost and maintenance-free procedure. It temporarily changes a glass pane from clear to translucent when the temperature reaches a certain limit.
The scientists at IAP developed small capsules filled with substances which change their refraction index depending on the temperature, so that light and infra-red rays will either be reflected or allowed through.
These microcapsules will be manufactured in a pilot plant in Adlershof, after which they will be mixed into cast resin by Tilse Formglas in Nennhausen, Brandenburg and there spread onto glass panes. These can then be processed into nearly any shape or size. The limits will only be determined by glass processing technology.
By Andreas Heins for Adlershof Special