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Photovoltaic (PV) systems have become an integral and widespread part of renewable energy generation. In combination with energy storage, they offer a variety of advantages such as increased self-sufficiency or improved grid stability. However, geographic location, subsidies, energy tariffs, size of PV panels and battery, and other factors significantly influence the overall performance and profitability of the system. Solving this complex task of system design and component dimensioning is not easy. The diversity and multitude of parameters therefore usually requires the help of, more or less complex, computer simulations. This led and still leads to a high publication activity on techno-economic and other optimizations for such systems. However, the operating strategies and component models are often oversimplified, leading to results with significant errors. The goal of this paper is to provide in-depth insight into component modeling and parametrization for PV module, battery energy storage, and inverter, as well as giving suggestions on appropriate control strategies. The focus lies on the description of suitable simple-but-accurate models and their parametrization. In order to avoid the effort of having to conduct measurements for component characterization, an approach relying on values presented in product data sheets is considered. Furthermore, the effects of model simplifications, as they are found in many publications, are shown. Finally, the importance of an uncertainty analysis for the entire simulation is discussed in order to gain insight into the accuracy of the calculated simulation results and their dependency on model- and input-parameters. • Photovoltaic system modeling/simulation. • Component modeling for PV module, battery energy storage and inverter. • Suitable simple-but-accurate models and their parametrization • Characterization relying on product data sheets with minimal informations. [ABSTRACT FROM AUTHOR]

Parabolic trough collectors are widely used to generate thermal and/or electrical energy from direct solar irradiation. These collectors use parabolic mirrors to precisely focus sunlight onto so-called absorber tubes. The optimal design and geometric alignment of all necessary components is essential in order to achieve a high degree of efficiency and a high energy yield. However, this optical fine-tuning process can be quite challenging and is in many cases avoided by using absorber tubes with larger diameters, which in turn cause greater thermal losses and a higher material effort. This paper describes a simple, yet reliable and quantifiable way to measure the optical performance of a parabolic trough collector using a commercial multi-junction solar cell (CPV). The presented measurement system allows for convenient adjustment of the parabolic mirror and the effective optimization of the overall collector design. The theoretical background is discussed and the test setup is described in detail. Measurement results are presented, ranging from the determination of the actual optical concentration ratio, the optimal centering and height adjustment of the absorber tube to the measurement of the contribution of the individual mirror segments, revealing that the investigated industrial parabolic trough collector can be improved in terms of optical accuracy. Finally, an optical surveillance of the mirror using a line laser was performed to validate the results. • New way to measure the optical performance of a parabolic trough collector. • Multi-junction solar cell (CPV) are used as a light sensor. • Theoretical background and various measurement setups and results are presented. • Optical concentration ratio of 128 x was measured with a parabolic trough collector. [ABSTRACT FROM AUTHOR]

A new design and retrofit approach for a concentrated photovoltaic thermal (CPV-T) system based on a parabolic trough collector is presented. The design differs from previous hybrid architectures, employing a significantly simplified topology in order to reduce costs while keeping electrical efficiency high. To achieve this ambitious goal, the absorber tube of a conventional parabolic trough collector used in thermal systems is replaced by a newly developed hybrid absorber equipped with multi-junction solar cells. This offers the advantage that existing solar thermal parabolic trough facilities can be easily retrofitted, making the system scalable and cost-effective. A scaled prototype of the system was designed and tested in Graz, Austria. During on-sun tests an average electrical system efficiency of 26.8 % with a simultaneous thermal efficiency of 48.8 % was measured using a geometric concentration ratio of 150 (DNI based). This leads to an overall average system efficiency of 75.5 %. Moreover, a solar cell peak efficiency of 30 % was achieved, one of the highest measured solar-to-DC efficiencies for a parabolic trough-based solar collector. Special attention was paid to the temperature difference between the solar cells and the heat transfer fluid in order to ensure sufficient cooling of the cells and maximize thermal efficiency. The electrical, thermal and overall efficiencies at different heat transfer fluid temperatures were measured (17 ° C - 90 ° C) and their coefficients were derived. This work serves as an experimental proof-of-concept for the application of solar cells in parabolic trough collectors, thereby opening up new possibilities for cost reduction of CPV-T systems. [ABSTRACT FROM AUTHOR]