One of the biggest thing holding back the adoption of Photo Voltaic panels (PV’S) is the way they look – normally as an ‘add on’ to a building on the roof or walls. Well it appears that technology is beginning to catch up and now some units are coming available which may overcome this prejudice.
In the US windows incorporating photovoltaic modules have been installed on the 110 storey Willis Tower(formerly Sears Tower) in Chicago.
The electricity-generating glazing system was fitted in November 2010 as part of a pilot project to modernize and improve the energy efficiency of the 38 year old building. The units were installed on the south-facing facade of the tower’s 56th floor.
If the trial is successful the installation will be rolled out to other floors. According to the manufacturer Pythagoras Solar, the installation has the potential to generate up to 2MW of solar power generation on the Willis Tower.
The solar windows are claimed to be the first transparent example of a standard insulating glazing unit to integrate a photovoltaic module. An acrylic prism system incorporated into the unit directs sunlight onto an integrated polycrystalline silicon solar cell, which is installed perpendicular to the window surface. The manufacturer claims the system can generate up to 140W of electrical power per square metre.
In addition to generating electricity the photovoltaic glazing units have the additional advantage that they will prevent direct solar radiation entering a building to help reduce its cooling load. However, the units do allow reflected light to pass through so that people inside the building can see out.
With large buildings like this the potential for ‘invisible’ renewables is huge, so lets hope this works out and we see it rolled out on many more buildings across the world.