A lot of sunlight hits tall office buildings, only to go to waste.
Their relatively small roofs don't offer much space for solar panels. A solar array crammed onto the top of a typical office tower could produce, at best, a tiny fraction of the electricity the building and its tenants need.
But what if the building's windows could serve as solar panels?
Pythagoras Solar in San Mateo has developed a window laced with solar cells, a window that generates and saves electricity at the same time.
Thin horizontal rows of silicon cells embedded between dual panes of glass catch light from above. And through a trick of optics, the window blocks direct sunlight from entering the building, cutting the amount of power needed for air conditioning.
"Instead of heating the room, the light generates clean solar power," said Gonen Fink, chief executive officer of Pythagoras. "It's relatively simple and straightforward optics. The challenge is making everything work together."
The window works well enough that earlier this week, Pythagoras won an award from the "GE ecomagination Challenge," an effort by General Electric Co. and several venture capital firms to find and fund promising technologies. Pythagoras was one of five companies given an "innovation award," which comes with a $100,000 grant.
