New Building-Integrated PV: Solar Windows

Skyscrapers like Chicago’s Willis Tower consume huge amounts of energy but have so far been unable to install solar panels because of the comparably small amount of roof space they have. However, solar technology company Pythagoras Solar has now found a way of using the massive amount of sunlight that hits the tall building walls every day.

Pythagoras’s new solar windows are now being tested on a few buildings, including the Willis Tower. The product is the world’s first transparent photovoltaic glass unit, and is used in place of regular windows, which do nothing to offset energy use. The typical window is also a huge burden in the summer; all offices want natural lighting, but that invites more heat for which we then need more air conditioning. The solar window allows light to come in, but can also use it to generate electricity, all in the same product. The panel, like traditional solar panels, still has grids on it, but they resemble a set of open venetian blinds. Other than that, it is also clear, just like an ordinary window. Its silicon PV cells sit between two panes of glass.

Pythagoras Solar’s new product combines the ideas behind self-tinting windows and thin film solar windows, which also tried to control the amount of light let in and generate power. The added aesthetic value of not actually looking like solar panels makes the product more attractive to architects and homeowners, as well. Prices have not been revealed yet, so interested residential customers may have to wait to install them. However, Founder and CEO Gonen Fink estimates that the typical consumer will recoup the cost of the windows after three to five years.

The unit, which has already won GE’s Ecomagination Challenge, joins other BIPV products like solar shingles and solar façade modules in using buildings themselves to generate energy.