SOPRAN

At the SOPRAN test stand for solar process heat applications at the DLR site in Cologne-Porz, researchers are demonstrating and testing the performance of line-focusing collectors for process heat systems and solar thermal power plants. The collectors concentrate the incident sunlight onto an absorber tube in which water flows and is heated.

A heating/cooling unit provides the heat transfer medium water at temperatures between 40 and 200 degrees Celsius with a mass flow of up to 8 cubic metres per hour for the solar field. The measurement technology and control system allows efficiency measurements in accordance with the international collector test standard ISO 9806 up to a temperature of 200 degrees Celsius. A dynamic procedure enables the measurement data to be analysed. This method is also used to analyse tests of power plant collectors in other DLR test facilities.

In particular, the precise control of the collector inlet temperature to ±0.05 Kelvin over long periods of time and for large collector areas makes it possible to identify deviations in the tracking. This also makes it possible to observe misalignments of the receiver tubes caused by jumps in the outlet temperature. Optical methods from the QUARZ laboratory are also used, in particular to determine the position of the mirrors. The various test methods can be used to determine how collectors can be optimised.

The system has a steam drum and a condenser which, in addition to operation with pressurised water, also enables direct steam generation in the collector field. The resulting saturated steam is a frequently used medium for heat transfer in production plants. Tests on the test bench have shown how direct evaporation can be safely implemented in the collector field. In follow-up projects, direct evaporation has now been successfully realised in industrial plants.

Consumers such as heat engines can be connected directly to the solar field in order to be operated with solar vapour. An absorption chiller operated with saturated vapour has already been successfully tested on the SOPRAN test bench.

Two types of collector are installed in the SOPRAN system: SL4600 from Solarlite, with an aperture area of 110 square metres, and collectors from Industrial Solar Technology (now Abengoa-IST) with an aperture area of 80 square metres. Together they provide an output of around 100 kilowatt.

Contact

Dr.-Ing. Eckhard Lüpfert

Head of Department Concentrating Solar Technologies
German Aerospace Center (DLR)
Institute of Solar Research
Linder Höhe, 51147 Köln-Porz
Germany

Dr.-Ing. Kai Wieghardt

Head of Department Concentrating Solar Technologies
German Aerospace Center (DLR)
Institute of Solar Research
Im Langenbroich 13, 52428 Jülich
Germany