A Pyrheliometer on Every Soitec Solar CPV Plant

Concentrix Solar became a division of the Soitec Group (listed on Euronext Paris) in December 2009. As the world’s leading innovator and provider of engineered substrate solutions, Soitec’s products serve as the foundation for today’s most advanced microelectronics. The Concentrix™ technology has also enabled Soitec to become a global leader in the manufacture of systems used by the concentrator photovoltaic (CPV) solar energy industry.

CPV is a very innovative technology which is revolutionizing the solar power industry. It uses a completely different concept from conventional photovoltaic (PV) technology. CPV systems use a concentrating optic - for example, mirrors or lenses - to bundle the sunlight and focus it onto very small solar cells which convert the light into electrical energy. By concentrating the sunlight, the required active area of the solar cell is reduced to only a small fraction of the area normally required by conventional solar cells. As a result, it is economically viable to use high quality solar cells with very high efficiencies.

The CPV technology of Concentrix uses special highly efficient solar cells which were designed to power satellites and which are now being used for the first time on Earth. These III-V based triple-junction solar cells consist of three different types of cells stacked on top of each other. Each cell type is sensitized to convert a certain spectral region of the solar radiation; short wave, medium wave and the infrared range. The Fresnel lens on top of each cell concentrates the solar radiation by up to 500 times. This technology is very well suited for use in areas with high direct radiation and high temperatures.

The best efficiency is achieved when the concentrators are exactly facing the sun. The two-axis tracking system ensures that the focal point of the concentrated sunlight is right on the cells at every moment during the day, following the sun with a very high accuracy of 0.1 °. The Concentrix tracking system is outstandingly robust. Even in high wind speeds, the trackers follow the sun without incurring losses.

With this technology, Concentrix Solar achieves AC system efficiencies of 25 percent, which are almost twice as high as those achieved by conventional silicon technologies. The Kipp & Zonen CHP 1 pyrheliometer is a vital component for checking and proving the efficiency of the system. For research and on installed solar power plants the accurate measurement of DNI (Direct Normal Irradiance) is crucial.

For more information visit www.soitec.com.