AIT Goehner develops central machine vision software for solar power plant in China

In the far north of China, in the Gobi Desert and on the border to Mongolia, a 50 MW all-weather solar thermal power plant is currently under construction. On an area of about 3.3 km², 14,500 heliostats (individual mirrors with an area of 50 m² each) are being set up in a circle around a solar tower about 200 m high. The heliostats track the sun and direct the solar radiation to a receiver (central heat exchanger) located at the top of the tower. This concentrated radiation is used to heat the nitrate salt in the receiver to a temperature of over 500° Celsius. Stored in huge tanks, energy can be generated around the clock, even at night and on cloudy days. The final goal is to achieve an annual clean electricity supply of around 200 million kWh.

For optimal efficiency of the power plant, the alignment of the heliostats must be calibrated periodically and during operation. On behalf of sbp Schlaich Bergermann Partner – one of the world’s leading German technology providers for solar power plant technology – AIT Goehner developed the central machine vision software for this purpose.

Eight extremely robust machine vision cameras – temperature fluctuations of -30° to +40° Celsius have to be compensated for – are arranged around the solar tower. These find up to 24 light points on a projection surface on the tower, simultaneously assign them to the heliostats and determine their position and shape. To do this, the images of the tower’s mantle surface are digitised, rectified and a background correction is carried out. By calculating back into the perspective of the respective heliostat, the shape of the respective beam is determined.