IBM and Airlight team up to build affordable 'solar sunflowers'
Airlight Energy, a Swiss-based supplier of solar power technology has partnered with IBM Research to bring affordable solar technology to the market by 2017. The system uses a dense array of high efficiency compound-semiconductor-based multi-junction photovoltaic chips similar to those used on orbiting satellites.
Each 1.1cm2 chip can concentrate the sun's radiation 2,000 times and convert 80 percent of it into useful energy to generate 12kW of electrical power and 20kW s of heat on a sunny day-enough to power several average homes.
The High Concentration PhotoVoltaic Thermal (HCPVT) system, which resembles a 10m high sunflower, uses a 40-square-metre parabolic dish made of patented fibre-based concrete, which can be moulded into nearly any shape in less than four hours and has mechanical characteristics similar to those of aluminium at one-fifth the cost.
The inside of the parabolic dish is covered with 36 elliptic mirrors made of 0.2mm thin recyclable plastic foil with a silver coating, which are then curved using a slight vacuum. The mirrored surface area concentrates the sun's radiation by reflecting it onto several microchannel liquid-cooled receivers, each of which is populated with a dense array of the multi-junction photovoltaic chips. The mirrors and the receiver are encased with a large inflated transparent plastic enclosure to protect them from rain or dust. The enclosure also prevents birds and other animals from getting in harm's way.
The photovoltaic chips are mounted on micro-structured layers that pipe treated water within fractions of millimetres of the chip to absorb the heat and draw it away 10 times more effectively than with passive air cooling. The 85-90degC hot water maintains the chips at safe operating temperatures of 105degC which otherwise would reach over 1,500degC. The entire system sits on an advanced sun tracking system, which positions the dish at the best angle throughout the day to capture the sun's rays.
The direct hot-water cooling design with very small pumping power has already been made commercially available by IBM in its high-performance computers, including SuperMUC, Europe's fastest supercomputer in 2012.
"The direct cooling technology with very small pumping power used to cool the photovoltaic chips with water is inspired by the hierarchical branched blood supply system of the human body," said Bruno Michel, manager, advanced thermal packaging at IBM Research.
An initial demonstrator of the multi-chip solar receiver was developed in a previous collaboration between IBM and the Egypt Nanotechnology Research Centre.
With such a high concentration and based on its radical design, researchers believe that with high-volume production they can achieve a cost of two to three times lower than comparable systems. Based on its current design, scientists estimate that the operating lifetime for the HCPVT structure is up to 60 years with proper maintenance.
The HCPVT system can also be customised with further equipment to provide drinkable water and air conditioning from its hot water output. For example, salt water can pass through a porous membrane distillation system, where it is vaporized and desalinated.
Airlight Energy and the IBM Corporate Service Corps (CSC) will team up to donate a HCPVT system to two deserving communities. Each winning community will receive a prototype HCPVT system from Airlight Energy, and be eligible for pro bono enablement and transformation support from IBM Corporate Service Corps. Applications from communities will be open in 2015 and the winners will be announced in December 2015, with installations beginning in late 2016.
Scientists at Airlight and IBM envision the HCPVT system providing sustainable energy to locations around the world including southern Europe, Africa, the Arabian Peninsula, the southwestern part of North America, South America, Japan and Australia. In addition to residences, additional applications include remote hospitals, medical facilities, hotels and resorts, shopping centres and locations where available land is at a premium.
Some of the initial funding for the development of the HCPVT system was provided to IBM Research, Airlight Energy, ETH Zurich and the Interstate University of Applied Sciences Buchs NTB in a three-year grant from the Swiss Commission for Technology and Innovation.
