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National Semiconductor
Launches PV Optimizer
DONNA COVENEY, MIT
Marc Baldo, associate professor
of electrical engineering and
computer science (left), and
Shalom Goffri, postdoc in MIT's
Research Laboratory of Electronics, hold examples of organic
solar concentrators.
MIT Announces Organic
Solar Concentrator
A team from MIT has announced an inexpensive technique for concentrating sunlight on solar cells, using flat glass. Details
were reported in the July 11 issue of Science,
in an article titled “High-Efficiency Organic
Solar Concentrators for Photovoltaics,” by
Michael J. Currie, Jonathan K. Mapel, Timothy D. Heidel, Shalom Goffri and Associate
Professor Marc A. Baldo.
The team adapted coating techniques
developed in lasers and organic light-emit-
ting diodes. A thin coat of organic dye is deposited on the upper
surface of a glass plate, using a
thermal evaporation process.
This creates a luminescent solar
concentrator (LSC), in which the
dye layer absorbs some of the
energy of incident photons,
allowing the glass to “capture” about 80 percent of the photons coming through. Instead
of transmitting straight through the glass,
these photons reflect within the glass plate.
The plate functions as a wave guide, analogous to fiber-optic cable. Photons are conducted to the edge of the plate, where they
meet conventional high-efficiency polysilicon photovoltaic cells bonded in place.
The work was sponsored in part by the
U.S. Department of Energy’s Office of Science and the National Science Foundation.
It will be commercialized by Covalent Solar,
launched early this year.
National Semiconductor Corp. announced
June 30 that it has entered the photovoltaic
market with new technology designed to
increase the overall energy output of solar
electric power-generating systems.
National’s SolarMagic is a small power-conditioning box wired to the back of each
PV module in any array. When wired together, the boxes route power around any module with degraded performance due to temporary shading, dirt or physical damage. The
system turns the array into a self-healing
network, maintaining the best possible power
output in adverse conditions.
REgrid Power Inc., one of the largest solar
installers in California, has begun system
testing. “We are impressed with National’s
SolarMagic technology in our field trials
and have seen a significant performance
improvement in
our solar installation,” said Tom
McCalmont, president and chief
executive officer of
REgrid. “We have SolarMagic circuit
observed energy mounts to a single PV
output improve- panel and wires to
ments of up to 44 neighboring units to
percent during shad- make a self-healing
ed conditions and network for optimum
12 percent overall.” power output.
NATIONAL SEMICONDUCTOR
