Scientific collaboration to develop affordable High Concentration PhotoVoltaic Thermal (HCPVT) system

Scientists have announced a collaboration to develop an affordable photovoltaic system capable of concentrating, on average, the power of 2,000 suns, with an efficiency that can collect 80 percent of the incoming radiation and convert it to useful energy.

The proposed system can be built anywhere sustainable energy, drinkable water and cool air are in short supply at a cost of three times lower than comparable systems.

A three-year, $2.4 million (2.25 million CHF) grant from the KTI - Swiss Commission for Technology and Innovation has been awarded to scientists at IBM Research; Airlight Energy, a supplier of solar power technology; ETH Zurich (Professorship of Renewable Energy Carriers) and Interstate University of Applied Sciences Buchs NTB (Institute for Micro- and Nanotechnology MNT) to research and develop an economical High Concentration PhotoVoltaic Thermal (HCPVT) system.

Based on a study by the European Solar Thermal Electricity Association and Greenpeace International 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.

The prototype 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.

The entire receiver combines hundreds of chips and provides 25 kilowatts of electrical power. The photovoltaic chips are mounted on microstructured 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.

Prof. Ralph Eichler, President of ETH Zurich and Dr. John Kelly, Senior Vice President IBM Research, present Aquasar. 

Photo: Michael Lowry, IBM Research – Zurich

Aquasar is an HPC system developed together by the two institutions using water to directly cool the integrated circuits.

The water with a temperature of about 60o C is used to heat the building of ETH Zurich.

The goal of this research project is to reduce the energy footprint of computing systems: It is assumed that computers use about 5 to 10% of the electricity worldwide.

Aquasar has a computing power of 6 Teraflops and consumes about 20 kilowatt of electricity. Water cooling on the chip may be the big next step to build larger supercomputers and to go to Exaflops (Computer processing speed of one quintillion (10^18) floating point operations per second).