Techniques designed for cooling computer chips make for more efficient photovoltaic cells and provide cheap energy for desalination
Pumping water through micro-channels on the surface of a solar panel not only makes it more efficient but can also make seawater drinkable.
Concentrated photovoltaic (CPV) cells use lenses to focus large areas of solar energy onto a relatively small section of photovoltaic material, so it is not surprising that they can reach temperatures of 120 °C. These high temperatures make the cells less efficient, reducing the amount of electricity they can produce.
That is why keeping them cool is so important, says Bruno Michel, head of advanced thermal packaging at IBM’s Zurich Research Laboratory in Switzerland. So with this in mind IBM has developed the “ultra-high concentrated PV”, a hybrid solar panel that incorporates technology originally developed to help cool computer chips. The idea is to use water-filled microchannels to cool the cell - the hot water would then be used in desalination.
In arid areas where power generation is difficult this can solve two problems at once, producing electricity and clean water, says Michel. “Usually in areas with high solar irradiance there is little demand for heating,” he says. “There is more demand for water.”
One method of desalination uses hot water to distil seawater, evaporating it to remove the salt. This is expensive and you normally need to heat the water first. So it is far more energy-efficient to use water already warmed from cooling solar cells.