// Sahara-like conditions in the south of Germany

With the 3X concentrating mirror at ZSW’s Widderstall testing facility, photovoltaic modules can be tested in the field under heavily increased loads that are close to the conditions encountered across the earth’s sun belt. The double-sided concentrating mirror tracks the sun with a motor. Irradiance achieved on the test modules reaches 3,000 W/m²; operating temperatures are limited to 60 °C with sensor-controlled ventilation. The irradiance received in the course of a year is about two and an half times higher than that of a module optimally oriented to the south and is more like that of a module located in Southern Europe and North Africa with over 2,000 kWh/m². The typical module temperatures of 50 °C to 60 °C correspond to these locations as well.

Due to the changing cloudiness and rapidly varying irradiance frequently occurring in the south of Germany, a larger number of module temperature cycles, and thus more thermal-mechanical stress, is caused than would be the case in the Sahara or another southern location. Overall, owing to the higher load on the test modules due to the concentrating mirror, it is possible to test these modules on a Central European test field in less time in terms of stability and the identification of any weaknesses in the design and PV module semiconductors.