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2018
Doctoral Thesis
Titel
Enhanced dynamic performance testing method for line-concentrating solar thermal collectors
Abstract
This thesis presents an enhanced dynamic performance evaluation method for line concentrating solar thermal collectors. Due to its dispatch ability and large storage capacity, concentrating solar power is considered of high relevance in the future renewable energy mix for both, electricity generation and industrial process heat supply. To fully exploit this potential and legitimize investments within this sector, a reliable and meaningful performance testing is essential. Dynamic testing is especially useful for outdoor testing, particularly on-site, lacking of laboratory facilities and therefore requiring in situ measurements. Those complex test conditions prevail for systems of larger dimensions such as line-concentrating collectors. A flexible, dynamic performance evaluation method allows for a significant reduction of testing time, effort, and consequently costs. Steady state operating requirements do not have to be fulfilled as demanded in the currently valid and widely accepted testing standard ISO 9806:2013.For this reason, the present thesis comprehensively addresses diverse aspects of dynamic in situ performance testing. Among smaller features, the elaborated approach includes a quality assessment of the evaluation results in terms of confidence computations. This is commonly not available for thermal collector testing so far. Besides, the thesis comprises an elaborate guideline for the proper selection of measurement instrumentation as well as a detailed proposal of an appropriate testing strategy for line-concentrating collectors. Applying both aspects as recommended, the quality of evaluation results maybe significantly increased. For the first time, the enhanced approach of this thesis additionally enables the dynamic evaluation of collectors operating with steam as a heat transfer fluid. Moreover, the newly advanced testing approach is thoroughly validated with measurement data. The thesis includes a comprehensive application of the proposed procedure to diverse test collectors, ranging from small-scale medium-temperature linear Fresnel collectors to large-scale high-temperature parabolic troughs, including different heat transfer fluids and receiver designs. The exemplary evaluations of this variety of test collectors succeed well. They thereby demonstrate the general capabilities and practicability, as well as a broad validity of the developed alternative testing method. It therefore proves to be a powerful and beneficial extension of the current testing standard to more complex test situations. Flexible and simultaneously reliable certification procedures are considered crucial for the further establishment of solar thermal technologies and their global acceptance.
ThesisNote
Zugl.: Braunschweig, Univ., Diss., 2018
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