Just Add Sun…

PV with a punch? Solar on steroids? The Red Bull of renewables?

Whatever you call it, IBM’s new research is raising eyebrows throughout the clean energy industry. CPV, also known as concentrator photovoltaics, utilizes a schoolyard science principle familiar to anyone who’s ever indulged a pyromaniacal fantasy with a magnifying glass. By effectively increasing energy yield through the use of CPV systems while simultaneously shrinking the amount of space and equipment needed, a team of researchers from IBM may have developed yet another way that energy could be cleanly and cheaply generated on a distributable scale.

While CPV technology has been around for more than 30 years, it had presented too many hurdles to be considered a viable source of energy production, particularly with regard to heat damage caused by the intensity of the focused rays on solar cells.

Until now.

Utilizing a technique developed to cool their computer chips (made of silicon, the same material used in most photovoltaics), IBM’s team was able to lower the temperature of the cells during use from 1600 degrees Celsius to 85 degrees. The technique involves the more efficient transfer of heat from the cell to a copper cooling plate through a liquid metal interface composed of a thin layer of a gallium-indium compound. Thus cooled, their CPV system was able to generate an apparent record 230 watts onto a solar cell the size of a square centimeter in the laboratory. This translates into 70 watts of power, or “five times the electrical power density” of conventional CPV cells. This means that the new improved system would be able to use significantly fewer cells to convert a greater amount of sunlight, cutting the number of system components (and the associated costs) ten-fold.

Now IBM just has to figure out how to shift these results from the controlled conditions of the lab to a practical setting. If achieved, CPV might vie with solar thermal for the leading role in the distributed energy saga.

The results were presented at the 33rd IEEE Photovoltaic Specialists conference back in May. Click here to check out the abstract.

Sources: “IBM Research Could Lead to Reduced Costs in Solar Farm Technology”, www.renewableenergyworld.com; “Understanding Solar Concentrators”, technical paper by George M. Kaplan; “Extending Photovoltaic Operation Beyond 2000 Suns Using a Liquid Metal Thermal Interface with Passive Cooling” (abstract), Theodore G. van Kessel, et al.


Posted on Sunday, September 14th, 2008 at 10:00 am | Tagged in Energy, Energy Efficiency, Green Building, Photovoltaics, Renewables, Sustainability, Technology | posted by Bill

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