The use of nanotechnology has led to the development of a temperature-sensitive filter that can be applied to the inside of a piece of glass. RavenBrick calls this patented material a thermochromic filter.
This filter is important in the environmental domain because it allows heat from the sun to enter a room or building when it is cold and blocks 90% or more of the sun’s energy when it is hot. Ravenbrick says it could save 30% of the heating and cooling costs throughout the year.
This is a great advancement in smartwindows. Previous technologies required electricity and a smart controller to achieve similar results.
![Nanotechnology Comes to High Tech Building Environments [video]](http://cdn.devicemag.com/wp-content/uploads/2013/08/Dow-building-485x276.jpg "Nanotechnology Comes to High Tech Building Environments [video]")
Smartwindows installed on the DOW building
The RavenBrick smartwindow is constructed as a normal double pane window with the inclusion of two added elements. On the exterior pane of glass, their RavenWindow thermochromic filter is deposited on the side of the glass facing the interior air gap of the window. The interior glass side of the window has a standard low-E coating facing the air gap.
When the exterior temperature is above the threshold temperature, the filter activates and blocks out the heat of the sun’s rays. When the temperature cools below the threshold temperature the filter turns off and the heat can pass through to the interior. The exact transition temperature is selected when the window is ordered, as the process allows for customized applications according to the needs of the building. The windows can also be ordered with a variety of decorative tints.
![Nanotechnology Comes to High Tech Building Environments [video]](http://cdn.devicemag.com/wp-content/uploads/2013/08/ravenbrick_smartwindowtechnology_780x343-485x213.jpg "Nanotechnology Comes to High Tech Building Environments [video]")
How the thermochromic filter works
The RavenBrick smartwindow can be used in LEED buildings and literally pays for itself in under four years. That is a very good ROI (Return On Investment). Besides the energy savings, damage to carpets and furniture through bleaching from the sun is reduced.
We should see many more companies offer similar products, either through obtaining the rights to use the patent or through research of their own. As more and more buildings are being built to LEED standards, we can see this and similar technologies being used to achieve greenness
