A three-year, $2.4 million grant from the Swiss Commission for Technology and Innovation has been awarded to scientists at IBM Research and ETH Zurich, among others, to harness the energy of 2,000 suns using a high concentration photovoltaic thermal system.  

The thermal system is expected to be able to convert 80 per cent of the collected solar energy, and is based on a low-cost, large dish-like concentrator and micro-channel cooled high performance photovoltaic chips, suitable for mass-production, says IBM.

A prototype of the HCPVT system is currently being tested at IBM Research – Zurich. Additional prototypes will be built in Biasca and Rueschlikon, Switzerland as part of the collaboration.

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 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.

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, says IBM. An initial demonstrator of the multi-chip receiver was developed in a previous collaboration between IBM and the Egypt Nanotechnology Research Center.

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.

[Image courtesy: IBM]