Overview of the photovoltaic (PV) outdoor test facility
In the foreground is the photovoltaic test bench, in the background are the test benches for radiation sensors and cloud cameras. Reference measurements of various radiation parameters are also carried out here. The test facilitiy is located at the Plataforma Solar de Almería (owner and operator: CIEMAT).
Photovoltaic test stand with various soiling measurement devices
Symmetrically constructed photovoltaic test stand with various soiling measurement devices at CIEMAT's Plataforma Solar de Almería. On the left are the cleaned PV modules, on the right the soiled ones.
Test stand for solar radiation measurement systems
Test stand for solar radiation measurement systems and cloud cameras with reference measurements of global radiation, direct radiation, diffuse radiation and circumsolar radiation. The test stand is located at CIEMAT's Plataforma Solar de Almería.
At the Photovoltaic outdoor test bench (PVot) at CIEMAT's Plataforma Solar de Almería, the German Aerospace Center is developing monitoring and prediction methods for photovoltaics (PV) under realistic conditions. The focus is on the detection and prediction of soiling of PV modules and the determination of front and rear side irradiance and albedo.
With accurate knowledge of the current and future soiling of PV modules, cleaning schedules and methods can be optimised. This reduces the operating costs of PV systems. Another focus of our research is the investigation and development of radiation measurement systems to support the design and operation of PV systems. Such measurement systems enable optimal system design and provide accurate monitoring of the condition of photovoltaic power plants. The measurements thus contribute to the rapid detection and correction of faults and ageing of power plant components.
The DLR Institute of Solar Research develops, operates and evaluates measurement systems for the detection of soiling at the PVot test facility. For the reference measurement, cleaned and uncleaned PV modules are set up in pairs each day and operated individually (via microinverters or I-V curve tracers at the maximum power point). The researchers compare the performance of the cleaned and uncleaned modules to derive an accurate reference for the level of soiling of the uncleaned PV modules. They are also using surveillance cameras installed on the test rig and camera-equipped drones to collect input data for practical approaches to determining the degree of soiling. In addition to camera-based methods for area-resolved measurements, they are also developing and evaluating compact measurement systems. To develop soiling models and forecasts, the scientists record measurements of particle concentration, precipitation, wind speed, air temperature and humidity.
Accurate monitoring of PV systems requires solar radiation data at module level, including the back of the module in the case of bifacial PV modules. The Institute of Solar Research operates appropriate test rigs to develop and evaluate practical measurement arrangements and systems for solar radiation on PV systems. At the PVot test bench, researchers also compare and evaluate commercial diffuse radiation measurement systems and DLR's own PyranoCam measurement system.
The measurement stands include:
Several reference cells and pyranometers in the module plane (front and rear side)
Albedo measurement
Sun tracker for broadband direct, diffuse and global radiation
