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.
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 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 micro-channel cooled module which can directly convert more than 30 percent of collected solar radiation into electrical energy and allow for the efficient recovery of an additional 50 percent 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."The design of the system is elegantly simple," said Andrea Pedretti, chief technology officer at Airlight Energy. "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." 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. 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, which is three times lower than comparable systems. The levelized 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. Water Desalination and Cool Air Current concentration photovoltaic systems only collect electrical energy and dissipate the thermal energy to the atmosphere. With the HCPVT packaging approach scientists can both eliminate the overheating problems of solar chips while also repurposing the energy for thermal water desalination and adsorption cooling.