By Andrea Pedretti
It would take only two percent of the Sahara Desert’s land area to supply the world’s electricity needs. Unfortunately, current solar technologies are too expensive and slow to produce, require rare Earth minerals and lack the efficiency to make such massive installations practical. To address this, scientists at Airlight Energy have teamed up with IBM and Swiss university partners to develop an affordable photovoltaic system that is capable of concentrating, on average, the power of 2,000 suns, onto hundreds of 1×1 cm chips.
The prototype system uses a large parabolic dish made from a multitude of mirror facets. The dish is attached to a tracking system that determines the best angle based on the position of the sun. Once aligned, the sun’s rays reflect off the mirror onto several microchannel liquid-cooled receivers with triple-junction photovoltaic chips. Each 1×1 centimeter chip can convert 200-250 watts, on average, over a typical eight-hour day in a sunny region.
The solar receiver system will use hot-water cooling processor technology, developed by our partners at IBM for supercomputers. Based on a collaboration with the Egypt Nanotechnology Research Center it was reapplied to cool photovoltaic chips.
I am particularly proud of the design, which I refer to as “frugal innovation.” I describe it this way because we have replaced expensive steel and glass with low cost concrete and simple pressurized metalized foils. Our business will manufacturer the small high-tech components, in particular the microchannel coolers and the molds, in Switzerland, while the remaining construction and assembly will be done in the region of the installation. This will create jobs in my home country and abroad, which is also rewarding for me.
To provide fresh water our colleagues at IBM are using a unique concept that they originally helped to develop for water-cooled supercomputers. With both the Aquasar and SuperMUC supercomputers water is used to absorb heat from the processor chips, which is then used to provide space heating for the facilities.
In the HCPVT system, instead of heating a building, the 90 degree Celsius water will pass through a porous membrane distillation system where it will be vaporized and desalinated. A large system could provide 30-40 liters of drinkable water per square meter, enough for a small town.
With such a high concentration and a radically low-cost design, we are targeting a cost-per-aperture area below $250 per square meter, which is three-times lower than comparable systems. This is a good price point for locations around the world including Southern Europe, Africa, the Arabic peninsula, the southwestern United States, South America, and Australia. Remote tourism locations are also an interesting market, particularly resorts on small islands, such as the Maldives, Seychelles and Mauritius.
Over the course of the next several months, thanks to a generous grant from the Swiss government, we will be building up new prototypes here at Airlight in Biasca and at the IBM lab in Rüschlikon, Switzerland. By Earth Day 2014 we should begin to have some very promising results.
Till then, Happy Earth Day.