WASHINGTON, July 10 (Xinhua) -- Imagine windows that not only provide a
clear view and illuminate rooms, but also use sunlight to efficiently help power
the building, according to a report by Engineers at Massachusetts Institute of
Technology (MIT).
The work, appearing in the July 11 issue of the journal Science, involves
the creation of a novel "solar concentrator." "Light is collected over a large
area (like a window) and gathered, or concentrated, at the edges," explains Marc
Baldo, leader of the work.
Rather than covering a roof with expensive solar cells, the new approach
needs only cells to be equipped around the edges of a flat glass panel, Baldo
says.
Because the system is simple to manufacture, the team believes that it can
be implemented within three years -- even added onto existing solar-panel
systems to increase their efficiency by 50 percent for minimal additional cost.
That, in turn, will substantially reduce the cost of solar electricity.
Solar concentrators in use today "track the sun to generate high optical
intensities, often by using large mobile mirrors that are expensive to deploy
and maintain," Baldo and colleagues write in Science. Further, "solar cells at
the focal point of the mirrors must be cooled, and the entire assembly wastes
space around the perimeter to avoid shadowing neighboring concentrators."
The MIT solar concentrator involves a mixture of two or more dyes that is
essentially painted onto a pane of glass or plastic. The dyes work together to
absorb light across a range of wavelengths, which is then re-emitted at a
different wavelength and transported across the pane to waiting solar cells at
the edges.
The project utilizes innovative design to achieve superior solar conversion
without optical tracking, says Aravinda Kini of the U.S. Department of Energy's
Office of Science, a sponsor of the work.