IBM Solar Dish Does Double Duty


IBM Researchers build solar concentrator that generates electricity and enough heat for desalination or cooling.

Cooling a supercomputer can provide clues on how to make solar power cheap, says IBM.

IBM Research today detailed a prototype solar dish that uses a water-cooling technology it developed for its high-end computers (see “Hot Water Helps Super-Efficient Supercomputer Keep Its Cool”). The solar concentrator uses low-cost components and produces both electricity and heat, which could be used for desalination or to run an air conditioner.


Researchers envision giant concentrators, built with low-cost materials, that produce electricity and heat for use in desalination or cooling. Credit: IBM Research.

The work, funded by $2.4 million grant from the Swiss Commission for Technology and Innovation, is being done by IBM Research, the Swiss company Airlight Energy, and Swiss researchers. Since this is outside IBM’s main business, it’s not clear how the technology would be commercialized. But the high-concentration photovoltaic thermal (HCPVT) system promises to be cost-effective, according to IBM, and the design offers some insights into how to use concentrating solar power for both heat and electricity.

Typically, parabolic dishes concentrate sunlight to produce heat, which can be transfered to another machine or used to drive a Stirling engine that makes electricity (see “Running a Marine Unit on Solar and Diesel”). With this device, IBM and its partners used a solar concentrator dish to shine light on a thin array of highly efficient triple-junction solar cells, which produce electricity from sunlight. By concentrating the light 2,000 times onto hundreds of one-centimeter-square cells, IBM projects, a full-scale concentrator could provide 25 kilowatts of power.

In this design, the engineers hope to both boost the output of the solar cells and make use of the heat produced by the concentrator. Borrowing its liquid-cooling technology for servers, IBM built a cooling system with pipes only a few microns off the photovoltaic cells to circulate water and carry away the heat. More than 50 percent of the waste heat is recovered. “Instead of just throwing away the heat, we’re using the waste heat for processes such as desalination or absorption cooling,” says Bruno Michel, manager, advanced thermal packaging at IBM Research.

Researchers expect they can keep the cost down with a tracking system made out of concrete rather than metal. Instead of mirrored glass on the concentrator dish, they plan to use metal foils. They project the cost to be 10 cents per kilowatt-hour in desert regions that have the appropriate sunlight, such as the Sahara in northern Africa.

One of the primary challenges of such a device, apart from keeping costs down and optimizing efficiency, is finding a suitable application. The combined power and thermal generator only makes sense in places where the waste heat can be used at least during part of the day. The researchers envision it could be used in sunny locations without adequate fresh water reserves or, potentially, in remote tourist resorts on islands. In those cases, the system would need to be easy to operate and reliable.

Is building integrated solar close to a tipping point?

QDOTS imagesCAKXSY1K 8Cost and performance considerations have long held back the market for building integrated photovoltaics (BIPV), but the steep drop in solar prices and the emergence of high-profile projects and EU policies are bringing new enthusiasm for incorporating it into building designs.


“We’re approaching a tipping point and at some point in the future, building integrated solar would be a must-have in the design of any new and significant building,” Mike Russell, managing director at Accenture, told Bloomberg.

Solar manufacturers, stung by diving prices, see BIPV as a way to offer a premium product that can provide strong margins. Architects see it as a way to incorporate distributed energy as part of the design process, rather than tacking on solar energy as an afterthought.





Heightened interest in energy efficiency, the rise of net-zero energy buildings and breakthroughs in component design all help drive growth.

In Europe, architecture firm Norman Foster and clients see it as a way to “produce eye-catching buildings” that meet new regulations, Bloomberg reported. Western Europe is expected to start as the biggest BIPV market because of its policy requiring all new buildings to be net-zero energy starting in 2021.

“Building integrated solar in office buildings and factories which generate energy consistently during daylight hours, while not requiring additional expensive land space or unsightly installations, is seen as the most obvious energy solution,” Gavin Rezos, principal of Viaticus Capital Ltd., told Bloomberg. The corporate advisory company has invested private equity in BIPV technology.

Two examples of new buildings sporting BIPV features are the new football stadium being built for the San Francisco 49ers in Santa Clara, Calif., which has technology developed by BASF SE; and the new Bloomberg LP headquarters in London being designed by Foster + Partners, which includes solar that’s incorporated into the roof instead of just laying on top of it.

The 55,000-seat Kaohsiung World Stadium in Taiwan is also a great demonstration of this: close to 9,000 panels are integrated directly into the building’s skin.

The CIS Tower

The CIS Tower in Manchester, England.And one of the most mature and largest examples of BIPV design is the vertical solar façade on the CIS Tower in Manchester, England (pictured right), which uses technology from Solar Century Holdings Ltd.

There’s a bright future for BIPV. While it generated just $606 million in revenue in 2012, more than 4.6 gigawatts (GW) of BIPV will come online by 2017, driving $2.4 billion in revenue that year, says Pike Research.

BIPV costs 10 percent more than traditional rooftop solar, Alan South, chief innovation officer at Solar Century, told Bloomberg.

“At the moment, it’s much cheaper to install a conventional module unless your roof is an unusual shape — and expensive solar installed on unsuitable roofs is a decorative design feature, not an energy solution,” adds Jenny Chase, solar analyst at Bloomberg New Energy Finance.

One reason is all the extra components needed to support BIPV within the structural design.

“While the individual cells are discreet and easy to integrate, they require cabling and additional elements that need to be carefully incorporated,” David Nelson, head of design at Foster + Partners, told Bloomberg.

His firm is no stranger to green building innovation. It designed and constructed New York‘s Hearst Tower, the first LEED Gold office building in the city.

As the BIPV market matures, Solar Century is developing technology that can be blended into roof tiles and slates. In the United States, Dow Chemical is already selling solar roofing shingles in more than a dozen states.

Solar panel image by Dabarti CGI via Shutterstock. CIS Tower image by mattwi1s0n via Flickr.