Characterization and measurements

When developing new key optical components, such as reflectors, reflector systems and absorbers, long-term stability must be taken into account, as must tests conducted to check these qualities using accelerated aging. Working alongside our Test Lab PV Modules, we carry out the following investigations, which also all feature optical quality testing.

• Temperature cycling tests
• Humidity/frost and humidity/heat tests
• Hail tests
• UV tests

Where test standards are available, we test the materials and components according to these guidelines.

We also investigate aging and soiling patterns of the reflective material used in concentrating collectors caused by outdoor exposure. We currently expose reflectors to outdoor conditions in Freiburg (temperate climate), in the Negev region in Israel (climate in which solar thermal power plants are typically found) and on Sicily (maritime climate).

The thermal characterization of collectors and receivers is essential for developing concentrating solar thermal collectors, materials and components. We support you by providing advice, conducting tests and taking measurements throughout the course of your development project.

Our services comprise:

• Lab and field measurements
• Thermal collector measurements using dynamic parameter identification or on a quasi-stationary basis (thermal output, optical efficiency, thermal losses)
• Thermal receiver tests in the lab for linear Fresnel systems and parabolic trough receivers (thermal loss coefficients)
• Analysis of heat distribution using thermal imaging or invasive sensors
• System optimization by combining actual measurement results with data gathered during collector modeling

Optical characterization is essential for developing concentrating solar thermal collectors and key optical components such as reflectors, reflector systems and absorbers. We support you by providing advice, conducting tests and taking measurements throughout the course of your development project. We can adapt our optical test procedures to suit your individual needs.

Our services comprise:

• Lab and field measurements
• Reflectors’ reflectivity (spectral, solar, angle dependent, specularity and beam expansion)
• Soiling measurements using a mobile reflectance measuring device
• Determination of the accuracy of parabolic reflector, dish and heliostat forms (fringe reflection technique, deflectometry)
• Luminance and intensity measurements and concentration analyses (focal lines, focal points)
• Absorber characterization (absorptivity and emissivity)
• Thermal imaging, analysis of heat distribution
• Tacheometry (mounting and orientating collectors in the array)

Taking long-term measurements on site and analyzing them (monitoring) form a crucial part of evaluating new system designs. They can be used for the quality assurance of components and systems, as well as to check yield predictions and plant functionality.

Our measuring and analysis processes undergo constant development. Drawing on our experience in lab and field measurements, we provide monitoring solutions for sub-arrays or entire plants. The sensors are selected according to the heat-transfer medium being used (steam, molten salt, thermal oil, pressurized water) and the temperature range. It is essential that the monitoring is carried out consistently even in remote areas in order to maintain data continuity. We have gained particular experience in monitoring and managing operations remotely for solar plants involved in water purification.