Maximizing the efficiency of solar arrays

April 04, 2012— Ottawa, Ontario

For many researchers, the journey from concept to prototype to product can be long and arduous, but immensely rewarding. Just ask Dr. Simon Fafard, a former NRC researcher.

Almost ten years ago, he founded Cyrium Technologies to develop photovoltaic solar cells based on quantum dots — tiny semiconductors too small to be visible to the naked eye. Today, Cyrium is marketing a family of high-efficiency products to solar power producers around the world, thanks in part to a three-year, NRC-sponsored project that tested the technology.

“It was a very useful exercise for us,” Dr. Fafard says of the SUNRISE project, short for Semiconductors Using Nanostructures for Record Increases in Solar-Cell Efficiency. “It allowed us to get experience in real operating conditions — heat, cold, snow, ice — all kinds of weather.”

SUNRISE was a multidisciplinary research collaboration that drew upon the expertise and resources of Ottawa-based Cyrium, Connecticut-based Opel International Inc., the Canadian Centre for Housing Technology*, and graduate students from Professor Karin Hinzer’s SunLab at University of Ottawa and from Université de Sherbrooke. “We made very good progress given the timelines and everything we had to do,” says NRC’s Dr. Frank Shepherd, who shared the leadership of the SUNRISE consortium with Dr. Trevor Hall of the University of Ottawa. “It was definitely very successful.”

The project encompassed everything from pouring concrete footings to assembling a complex and highly efficient photovoltaic system, monitoring its performance and measuring the electrical output. At the outset, Cyrium's solar cell chip devices had been tested in a laboratory using sun-simulating lamps, which, as Dr. Fafard notes, could never fully duplicate the sun’s light and energy spectrum.

The devices were installed in units, designed by Opel, which included sophisticated optical elements that functioned like magnifying glasses and increased by a factor of 500 the amount of sunlight hitting Cyrium's quantum dot semiconductor solar cell devices. As well, Cyrium’s “triple-junction” cells captured energy from multiple bands of the solar spectrum, something conventional solar panels generally don't do. To maximize the amount of energy generated, the units were assembled into panels and mounted on a dual axis tracker, built in such a way that all panels could rotate and tilt to follow the movement of the sun across the sky.

Peak energy production

The entire system was erected on concrete footings at the Canadian Centre for Housing Technology (CCHT), which features, among other things, two identical detached homes side by side that serve as test and control units. On the sunniest day of the 120-day test period, the concentrated photovoltaic system produced a total of 19.4 kWh of electrical energy — with a peak 5-minute production of 2.18 kW AC — enough to meet 96 percent of the house’s total electrical needs on that day.

"These results have never before been produced in Canada, nor the world, concludes a final report on SUNRISE prepared under the supervision of Dr. Shepherd and Dr. Hall. This is incredibly significant because, as the world shifts toward renewable energy sources, solar systems need to increase the amount of power generated per area."

The report also notes that the collaborative approach was an essential component of the SUNRISE results.

"Simply stated, the project objectives could not have been achieved by any subset of the partners acting alone, it states. Each of the partners has complementary skills and facilities, all of which (were) critical to project success."

The SUNRISE system provides electricity for the adjacent CCHT test house.

SUNRISE not only demonstrated the viability of Cyrium’s technology, but also helped the company to begin marketing a line of standard cell size products under the trade name QDEC, which stands for quantum dot enhanced cell. Dr. Farfard says his firm has made sales to clients in China, Europe and the U.S., and is now knocking on the doors of other systems manufacturers worldwide.

Currently, the market for concentrator photovoltaic cells — which combine panels with optical technology to focus solar energy and trackers — is small compared to the demand for conventional photovoltaic cells. But the market is expected to grow exponentially in the next three to five years and Cyrium stands a better chance of capturing a significant share thanks in part to the results achieved through the SUNRISE project.

“There are a lot of players trying to commercialize the trackers and optics or, like us, trying to make more efficient chips,” says Dr. Fafard. “SUNRISE gave us an opportunity to integrate all these components and see how they work in the field. The real fun starts when you learn from that and better optimize the next generation.”

*Located in Ottawa, the Canadian Centre for Housing Technology is jointly operated by NRC, Natural Resources Canada, and the Canada Mortgage and Housing Corporation.

Enquiries: Media relations
National Research Council of Canada
613-991-1431
media@nrc-cnrc.gc.ca

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