Presentation, evaluation and validation of measurement results from operation tests of rotation and expansion performing assemblies during the commissioning of the REPA Test Rig

Kurzfassung

Critical parts in Parabolic Trough Collector (PTC) power plants are the flexible pipe connections, also called Rotation and Expansion Performing Assemblies (REPAs) between the absorber tubes and the feeding pipes. REPAs have to compensate tracking movements of the collector to follow the course of the sun and the heat dilatation of the absorber tube. REPAs have to withstand an operating time of 30 years under harsh weather conditions. Damages at these components lead to leakages and breakdowns of the PTC power plant. The consequences are safety risks, economic losses and environmental damages. Failure mechanisms will be investigated at the REPA test under near-operating conditions by simulating accelerated REPA life cycles. The first part of this thesis gives thereby an overview of the state of the art in PTC power plants and the structure and function of the REPA test rig. Furthermore, the undertaken efforts are described to contribute the commissioning of the first of four sensors for the force-measurement at test rig to measure the resulting REPA reactions. The two integrated measurement setups are presented to execute the first tests with rotation and translation movements as simulation of typical collector motions. Measurement results have been evaluated for the first tests during the commissioning of the test rig to determine the forces and moments for rotation and translation movements under different operating parameters. The second test results are presented to define the additional influences from the pipe section between the two installed REPAs at the test rig. The impact of the traverse piping on the total measurement has been investigated. The measurement results are compared and validated with the simulation (ROHR2) model of the traverse piping. Moreover, measures are presented to decrease uncertainties by the force and Moment measurement. With this first measurement results, the following future life cycle test can be evaluated more in detail and the test rig commissioning can be continued and also the installation of the force-measurement sensors.