IBM replants chip-cooling tech in solar farms

IBM has applied its silicon expertise to cool concentrating photovoltaics, high-powered solar panels used in solar farms.

IBM has developed technology that will let solar cells withstand the heat of more than a 1,000 suns.

At a technical conference on Thursday, representatives from IBM Research's photovoltaics research will present a method for cooling concentrating photovoltaics, a solar design where light is magnified onto high-performance solar cells.

A SolFocus 6.2-kilowatt CPV device being tested in Spain. Click on the image to see a photo gallery of other concentrating photovoltaic systems. SolFocus

Heat is a serious issue when it comes to concentrating photovoltaics, or CPV. The efficiency of cells degrades at high heat and can damage, and conceivably destroy, equipment at extremely high temperatures.

IBM said that its liquid-metal cooling technique, adapted from high-powered computers' chips, can remove roughly three-quarters of the heat generated by a CPV system.

CPV arrays use lenses and mirrors to magnify light onto solar cells that convert light to electricity. By cramming more light onto cells, the panels can generate more electricity.

The technology, which has been around for decades, is being pursued once again by a number of companies, most of which are designing systems for solar power plants.

These plants have rows of CPV systems that track the sun during the day and magnify light hundreds of times.

As part of IBM's Big Green Innovations initiative, researchers looked into applying the company's chip design and manufacturing expertise in solar. It found that CPV companies had not paid enough attention to thermal problems, particularly as they move to higher light concentrations.

"It's clear that everybody wants to go to higher concentrations," said Supratik Guha, lead scientist for photovoltaics at IBM Research. "In the last few years, CPV has sort of been trying to make a comeback and if you look at the numbers, it does have the potential to be really cheap."

IBM looking at CIGS
Because heat dissipation is important for its high-end processors, IBM has developed a cooling system where a thin layer of liquid metals circulates behind a chip to transfer the heat from the chip to a "cooling block."

IBM has built a prototype of a solar concentrator that uses the cooling technology from its high-end chips. IBM

IBM has built a prototype of the thermal interface layer on a CPV system. In tests, it found that the technique can dramatically lower the heat of high-concentration devices.

The technique only makes sense for very high levels of concentration, which are used on expensive, high-efficiency triple-junction solar cells, said Guha.

IBM doesn't intend to manufacture CPV devices itself but it does hope to license its thermal interface layer to solar manufacturers, he said.

In addition to working on thermal issues, IBM Research is working on "solution process" techniques for manufacturing CIGS cells. The solution process would be an alternative to the slower evaporation process for making CIGS cells.

IBM is also working on manufacturing silicon solar cells on glass. More fundamental research focuses on improving solar cell efficiency through nanowires and nanoparticles, explained Guha.

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