IBM To Develop Solar Collector For Green Energy Push

IBM is collaborating with other scientists to develop an affordable photovoltaic system that could potentially resolve humanity’s ongoing need for huge amounts of renewable energy.

The new system is capable of concentrating solar radiation 2,000 times, and converting 80 percent of the incoming radiation into useful energy.

Energy, Cooling, Water

The effort to develop a High Concentration Photovoltaic Thermal (HCPVT) system is funded by a three-year, $2.4 million (£1.6m) grant from the Swiss Commission for Technology and Innovation awarded to scientists at IBM Research; Airlight Energy, a supplier of solar power technology; ETH Zurich’s Professorship of Renewable Energy Carriers and Interstate University of Applied Sciences Buchs NTB (Institute for Micro- and Nanotechnology MNT). The HCPVT system can provide desalinated water and cool air in sunny, remote locations where they are often in short supply.

IBM made its announcement on 22 April, Earth Day. Based on a study by the European Solar Thermal Electricity Association and Greenpeace International, technically, it would only take two percent of the solar energy from the Sahara Desert 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, IBM said.

“The prototype High Concentration Photovoltaic Thermal (HCPVT) system is unique in that it is highly efficient at harnessing the sun’s radiation using affordable materials, like cement,” Christopher Sciacca, communications manager at IBM Research – Zurich, told eWEEK. “This will reduce the cost by 3X when compared with similar systems. If we are successful we can change the conversation about the cost of fossil vs. solar because the levelised 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.”

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 1×1 centimetre 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.

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, IBM said.

Supercomputer Lessons

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 Centre.

“For the past several years scientists in Zurich have been focused on using hot water to cool supercomputers and we have successfully demonstrated this with Aquasar and SuperMUC, which was in June 2012 the fastest supercomputer in Europe,” Sciacca said. “In a collaboration with the Egypt Nanotechnology Research Centre this same concept was developed to also cool chips used in a solar concentrator. This is a significant achievement in that we can harness the solar radiation of the sun 2000x. In fact, our calculations support it up to 5,000x.”

“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, in a statement. “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, in a statement. “We replace expensive steel and glass with low cost concrete and simple pressurized metalised 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 cement will be used for dish concentrator, Sciacca said. This is unique in that steel is typically used, he said. However, in using cement the team is able to dramatically reduce the cost and it enables the construction to take place where the HCPVT is needed, which creates local jobs, he stressed.