Photogrammetric Measurement of the Optical Performance of Parabolic Trough Solar Fields

Kurzfassung

Renewable energies are characterized by deviations between demand and supply. Concentrating solar power (CSP) offers not only the efficient and potentially competitive use of sunlight, but also the use of thermal energy storage, in order to cope with these fluctuations. Various technologies are available for the concentration and conversion of sunlight into thermal energy, with parabolic trough collector (PTC) having the largest market share at the time. The optical efficiency of the solar field has a significant influence on the economic viability of the power plant. Measurement methods for determining the geometric accuracy of concentrator systems are therefore an important part of research & development, construction, commissioning and running operation. This thesis describes the development of the airborne QFly measurement technique for the qualification of PTC solar fields. Compared to the state of the art, the stationary camera has been replaced by a unmanned aerial vehicle (UAV) with corresponding payload. This allows a fully automatic measurement of the entire power plant. The QFly procedure has two approaches. The QFlyHighRes approach allows the precise and differentiated measurement of concentrator geometry at a spatial resolution of 6mm/pixel and a flight altitude of 30 meters. The measurement volume is approx. 2 loops per day and is therefore suitable for the characterization of prototypes and random check of the solar field. The QFlySurvey method is used for the rapid Screening of entire power plants. At a flight altitude of 120 to 250 meters, tracking information and the effective concentrator form can be obtained at a reduced spatial resolution. Within the scope of this work, both methods are described and subjected to an uncertainty analysis and validated with independent benchmark measurement methods. In the end, the process is used to identify defects with the aid of geometric measured data. Numerical ray-tracing (RT) enables an energetic and economic evaluation of potential optimization measures. The airborne geometry measurement in parabolic trough power stations can thus be regarded as mature. Further need for action and possible applications arise with the interface with the yield analysis, the airborne thermographic determination of heat losses and the extension of the measuring technology on solar tower power plants.