IBM today said its researchers are developing a solar power system that concentrates solar radiation 2,000 times by using a human-blood supply modeled way of cooling and converting 80% of Sun's heat into useful energy. IBM says the system can also desalinate water and cool air in sunny, remote locations where such systems are often in short supply.
IBM says current concentration photovoltaic systems collect electrical energy and dissipate the thermal energy to the atmosphere. But this prototype known as a High Concentration PhotoVoltaic Thermal system eliminates the overheating problems of solar chips while repurposing the energy for thermal water desalination and adsorption cooling.
IBM and researchers from Airlight Energy, a supplier of solar power technology; ETH Zurich; Interstate University of Applied Sciences Buchs NTB said they have been awarded a three-year, $2.4 million grant from the Swiss Commission for Technology and Innovation to research and develop HCPVT.
The direct cooling technology the HCPVT systems uses is "inspired by the hierarchical branched blood supply system of the human body and has been tested by IBM scientists in high performance computers, including the Aquasar supercomputer and SuperMUC, IBM said. Those computers use water to absorb heat from the processor chips, which is then used heat the facilities.
IBM says the prototype HCPVT system uses a large parabolic dish, made from a multitude of mirror facets, which are attached to a sun tracking system. The tracking system positions the dish at the best angle to capture the sun's rays, which then reflect off the mirrors 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.
The entire receiver combines hundreds of chips and provides 25 kilowatts of electrical power. The photovoltaic chips are mounted on micro-structured layers that pipe liquid coolants within a few tens of micrometers off the chip to absorb the heat and draw it away 10 times more effective than with passive air cooling, IBM said. The coolant maintains the chips almost at the same temperature for a solar concentration of 2,000 times and can keep them at safe temperatures up to a solar concentration of 5,000 times.
The solar concentrating optics will be developed by ETH Zurich. "Advanced ray-tracing numerical techniques will be applied to optimize the design of the optical configuration and reach uniform solar fluxes exceeding 2,000 suns at the surface of the photovoltaic cell," said Aldo Steinfeld, Professor at ETH Zurich in a statement.
With such a high concentration and a low cost design, scientists believe they can achieve a cost per aperture area below $250 per square meter, which is three times lower than comparable systems, IBM claims. The cost of energy will be less than 10 cents per kilowatt hour (KWh). For comparison, feed in tariffs for electrical energy in Germany are currently still larger than 25 cents per KWh and production cost at coal power stations are around 5-10 cents per KWh, IBM said.
"We plan to use triple-junction photovoltaic cells on a micro-channel cooled module which can directly convert more than 30% of collected solar radiation into electrical energy and allow for the efficient recovery of an additional 50% waste heat," said Bruno Michel, manager, advanced thermal packaging at IBM Research. "We believe that we can achieve this with a very practical design that is made of lightweight and high strength concrete, which is used in bridges, and primary optics composed of inexpensive pneumatic mirrors -- it's frugal innovation, but builds on decades of experience in microtechnology. "
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