Sun-powered Sunflower


Solar Energy Harvester Could Soon Become the First "Drop-in" Machine to Provide Renewable Energy, Water and Heat to Off-grid Communities in Remote Regions

The 10-metre-high, sun-tracking dish has been designed to be transported in a single shipping container, so it can be delivered to any location. It is being developed by Airlight Energy of Biasca, Switzerland. As well as clean water and electricity, it can generate heat or, with the addition of a heat pump, provide refrigeration.

The core technology is a water-cooled solar panel developed by Bruno Michel and his colleagues at IBM, for which Airlight has licensed the patents. Mirrors on the flower-shaped structure direct the sun's rays onto six of the panels, where the sunlight is concentrated 2000 times.

Each panel holds 25 photovoltaic chips cooled by water flowing in microchannels underneath. These carry the heat away at a rate that leaves the microchips at their optimal operating temperature. That makes the Sunflower more efficient than existing photovoltaic concentrating generators, so it needs a quarter of the panels to produce the same power. This makes it far cheaper, says Michel.

In coastal areas, the heated water can drive a low-temperature desalinator, also developed by IBM. It heats seawater to create vapour that passes through a polymer membrane and condenses in a separate chamber. The process is then repeated three times to extract maximum water. IBM claims this can produce 2500 litres of fresh water per day. In non-coastal areas, a water purifier could be fitted instead.

The structure is designed to keep costs down. Solar mirrors would normally be made of heavy, expensive polished glass, but here each 1-metre mirror is made of metallised foil. "The same material potato chip and chocolate wrapping is made of," says Ilaria Besozzi of Airlight.

If the flow of cooling water failed for any reason, the solar chips would quickly reach 1500 °C and melt. However, a low vacuum keeps the foil mirrors in their concave shape, and releasing this defocuses the sunlight, preventing a solar-chip meltdown.

Sources: NewScientists, GizMag

Nice Video from IBM Research and Airlight Energy 

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