Earth Day Collaboration Aims to Harness the Energy of 2,000 Suns

It would take only two percent of the Sahara Desert’s land area to supply the world’s electricity needs. Unfortunately, current solar technologies on the market today 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 aren't thinking bigger, in fact they are thinking much smaller -- at the nanoscale.

A new collaboration between IBM, Airlight Energy and Swiss university partners 
will develop an affordable photovoltaic system capable of concentrating, on average, the power of 2,000 suns, onto hundreds of 1x1 cm chips.
Rendering by Airlight Energy of the prototype
HCPVT system.

The prototype High Concentration PhotoVoltaic Thermal (HCPVT) system uses a large parabolic dish, made from a multitude of mirror facets, which 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 1x1 centimeter chip can convert 200-250 watts, on average, over a typical eight hour day in a sunny region. 
Such system can be profitably applied in sunny regions where sustainable energy, drinkable water and cool air are in short supply.

The direct cooling solution with very small pumping power is inspired by the hierarchical branched blood supply system of the human body and has been already tested by IBM scientists in high performance computers, including Aquasar. An initial demonstrator of the multi-chip receiver was developed in a previous collaboration between IBM and the Egypt Nanotechnology Research Center.

“We plan to use triple-junction photovoltaic cells on a microchannel-cooled module which can directly convert more than 30 percent of collected solar radiation into electrical energy, and allow for the efficient recovery of waste heat above 50 percent,” said Dr. Bruno Michel, manager, advanced thermal packaging at IBM Research - Zurich.

“The design of the system is elegantly simple.” said Andrea Pedretti, CTO of Airlight Energy.

He adds, “We replace expensive steel and glass with low-cost concrete and simple pressurized metalized foils. The small high-tech components, in particular the microchannel coolers and the molds, can be manufactured in Switzerland, with the remaining construction and assembly done in the region of the installation. This leads to a win-win situation where the system is cost competitive and jobs are created in both regions.”

To provide fresh water, IBM scientists and engineers are utilizing a world leading technology they developed 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 be used to heat salty water that then passes through a porous membrane distillation system where it is vaporized and desalinated to generate 30-40 liters of drinkable water per square meter of receiver area per day. A large multi-tracker system could thereby provide enough water for a town.

With such a high concentration and a radically low cost design, scientists believe they can achieve a cost per aperture area below $250 per square meter. This is three times lower than comparable systems. The levelized cost of energy will be less than 10 cents per kilowatt hour (KWh).

The scientists envision the system providing sustainable energy and fresh water to locations around the world including Southern Europe, Africa, Arabic peninsula, 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.

Happy Earth Day.

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