Thesis (MScIng)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves [71]-74). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves [71]-74). Also available on the Internet.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2005. / Parabolic trough solar collectors (PTSCs) constitute a proven source of thermal energy for industrial process heat and power generation, although their implementation has been strongly influenced by economics. In recent years, environmental concerns and other geopolitical factors have focused attention on renewable energy resources, improving the prospects for PTSC deployment. Further work is needed to improve system efficiencies and active areas of research include development of advanced heat collecting elements and working fluids, optimisation of collector structures, thermal storage and direct steam generation (DSG). A parabolic trough collector, similar in size to smaller-scale commercial modules, has been developed locally for use in an ongoing PTSC research programme. The aim of this study was to test and fully characterise the performance of the collector. Specialised logging software was developed to record test data and monitor PTSC performance in real-time. Two heat collecting elements were tested with the collector, one unshielded and the other with an evacuated glass cover. Testing was carried out according to the ASHRAE 93-1986 (RA 91) standard, yielding results for the thermal efficiency, collector acceptance angle, incidence angle modifier and collector time constant. Peak thermal efficiency was 55.2 % with the unshielded receiver and 53.8 % with the glass-shielded unit. The evacuated glass shield offered superior performance overall, reducing the receiver heat loss coefficient by 50.2 % at maximum test temperature. The collector time constant was less than 30 s for both receivers, indicating low thermal inertia. Thermal loss tests were conducted and performance of the trough’s tracking system was evaluated. The measured acceptance angles of 0.43° (unshielded) and 0.52° (shielded) both exceeded the tracking accuracy of the PTSC, ensuring that the collector operated within 2 % of its optimal efficiency at all times. Additionally, experimental results were compared with a finite-volume thermal model, which showed potential for predicting trough performance under forced convection conditions.

Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Sheldon Jeter; Committee Member: Sam Shelton; Committee Member: Srinivas Garimella

Das Erkenntnistransferprojekt baut auf die im SPP-Projekt „Leichte Verformungsoptimierte Schalentragwerke aus mikrobewehrtem UHPC am Beispiel von Parabolrinnen solarthermischer Kraftwerke“ (s. S. 536 ff .) erzielten Ergebnisse der ersten Förderperiode auf. Der Fokus liegt auf der Entwicklung von linienartig verstärkten, vollwandigen Parabolschalen mit zur bestehenden Kraftwerkstechnik passenden EuroTrough-Rinnenabmessungen. Es sollten die bisherigen Erkenntnisse zusammen mit professionellen Anwendungspartnern vorwettbewerblich ausgebaut werden, so dass sie Grundlage für eine Serienfertigung bilden können. Dementsprechend setzten sich die Kooperationspartner aus dem Deutschen Zentrum für Luft- und Raumfahrt DLR (Systemführer für linienfokussierende Solarkraftwerke), der Fa. Solarlite CSP (Hersteller von Solaranlagen in Parabolrinnentechnik), der INNOGRATION GmbH (Hersteller von Stahlbetonfertigteilen) und der Fa. Dyckerhoff Zement (Hersteller von Ausgangsstoffen für Hochleistungsbetone) zusammen.

This thesis presents and demonstrates procedures to model and optimize the collector field of a parabolic trough solar thermal power plant. The collector field of such a plant is universally organized into parallel loops of solar collectors. Heat transfer fluid returning from the energy conversion plant is heated to a moderately high temperature in the field. Typically fluid enters a collector loop around 270 °C and leaves at 380 °C. The fluid is then returned to the plant to generate steam. In the first part of this thesis, the collector field and the energy conversion system of a typical parabolic trough solar thermal power plant are modeled. The model is compared with actual performance data and is enhanced and verified as necessary. Originally, the collectors in the plants under consideration were provided with evacuated tube receivers of the highest feasible efficiency without much regard for cost effectiveness. In practice, these receivers have failed at an unexpected rate and need replacement. It is unlikely that a very expensive evacuated tube receiver is now the most cost effective for every location in a collector loop. In particular, a receiver optimized for 270 °C operation may not be optimal at 380 °C. For example, a relatively inexpensive receiver with a flat black absorber and no vacuum may be more cost effective in the lower temperature segments of a loop. In the second part of this thesis, a procedure for the optimum deployment of collectors is developed and demonstrated. The results of this research should be directly applicable to the refurbishment and upgrading of several of the largest solar energy plants in the world.

aus dem Inhalt: „Die im Teilprojekt Mark/Schnell des SPP 1542 erbrachten Entwicklungen an Parabolrinnen (siehe S. 536 ff . des vorliegenden Buches) haben gezeigt, wie aussichtsreich die Verwendung von Feinkornbetonen für die Herstellung hochpräziser, formstabiler Bauteile ist [1], [2]. Die gewonnenen Erkenntnisse und die Nachfrage aus der Solartechnik ermutigen zur Übertragung auf verwandte Anwendungsgebiete, nämlich auf Heliostate [3] unter der Leitidee einer weitgehend industrialisierten Präzisionsfertigung. Wegen der extrem hohen Wiederholungszahl gleicher oder sehr ähnlicher Fertigteile sind Heliostate für den Betonfertigteilbau auch unter wirtschaftlichen Gesichtspunkten in nahezu idealer Weise geeignet....” / from the content: „Recent developments on parabolic troughs (see p. 536 seq. of this book) in Mark/Schnell’s project of the SPP 1542 have shown that the use of finegrained concrete is a promising alternative for the manufacture of highly precise components with low deformations [1], [2]. Their findings and requests in solar technology have encouraged a transfer to related fields of application, namely to heliostats [3]. The guiding principle is broadly industrialized precision manufacturing. Due to an extremely high number of identical or utmost similar precast elements, heliostats seem to be ideally suited for precast concrete construction from an economic point of view....”