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Solar cathedral window in Canada.

Not all the sunlight falling on the stained-glass windows in a new Canadian cathedral passes through to the congregation inside. Some of the light generates electricity.
The Cathedral of the Holy Cross in Saskatoon, the largest city in the province of Saskatchewan, is the first cathedral with photovoltaic cells integrated into three of its south-facing windows. The solar-powered windows feature modern designs by Canadian glass artist Sarah Hall of Toronto, Ontario. Titled “Lux Gloria,” or “The Light of Glory,” the tinted patterns are meant to evoke the broad, sweeping prairies as well as religious symbols.
Hall says the project took three years from start to finish, including one year of discussions with the clients, the Roman Catholic diocese of Saskatoon. They chose 1,113 silver-colored polycrystalline solar cells to complement the white panels of the building's facade. The largest of the three windows is 11.3 m high and 3.7 m wide.
After Hall did the preliminary design of the solar array and supporting glass, solar engineer Christoph Erban of Aachen, Germany, arranged the cells to maximize their efficiency as well as their ease of installation. Glasmalerei Peters GmbH of Paderborn, Germany, fabricated the 54 separate glass panels that make up the three windows. The biggest challenge, according to Hall, was getting the 54 panels into position 31.6 m above the ground. She says, “Saskatoon has strong winds!”
Together, the windows are expected to yield about 2,500 kWh of energy annually. In addition to generating electricity, the stained-glass windows help shade parts of the cathedral's interior, including the organ loft, from the brilliant sun. Saskatoon claims to be the sunniest city in Canada, with an annual average of 2,381 cloudless hours.
Lux Gloria is Saskatchewan's first building-integrated photovoltaic system. Hall is now in the final stages of designing another solar project, called “Waterglass,” for the Harbourfront Centre in Toronto.