@inproceedings{SattlerCaminosUerlingsetal.2020,
  author    = {Sattler, Johannes, Christoph and Caminos, Ricardo Alexander Chico and {\"U}rlings, Nicolas and Dutta, Siddharth and Ruiz, Victor and Kalogirou, Soteris and Ktistis, Panayiotis and Agathokleous, Rafaela and Jung, Christian and Alexopoulos, Spiros and Atti, Vikrama Nagababu and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf},
  title     = {Operational experience and behaviour of a parabolic trough collector system with concrete thermal energy storage for process steam generation in Cyprus},
  series = {AIP Conference Proceedings},
  booktitle = {AIP Conference Proceedings},
  number    = {2303},
  doi       = {10.1063/5.0029278},
  pages     = {140004-1 -- 140004-10},
  year      = {2020},
  language  = {en}
}
@inproceedings{SattlerAlexopoulosCaminosetal.2019,
  author    = {Sattler, Johannes, Christoph and Alexopoulos, Spiros and Caminos, Ricardo Alexander Chico and Mitchell, John C. and Ruiz, Victor C. and Kalogirou, Soteris and Ktistis, Panayiotis K. and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf},
  title     = {Dynamic simulation model of a parabolic trough collector system with concrete thermal energy storage for process steam generation},
  series = {AIP Conference Proceedings},
  volume    = {2126},
  booktitle = {AIP Conference Proceedings},
  issn      = {0094243X},
  doi       = {10.1063/1.5117663},
  pages     = {150007-1 -- 150007-8},
  year      = {2019},
  language  = {en}
}
@inproceedings{SattlerSchneiderAngeleetal.2022,
  author    = {Sattler, Johannes Christoph and Schneider, Iesse Peer and Angele, Florian and Atti, Vikrama and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf},
  title     = {Development of heliostat field calibration methods: Theory and experimental test results},
  series = {SolarPACES conference proceedings},
  booktitle = {SolarPACES conference proceedings},
  number    = {Vol. 1},
  publisher = {TIB Open Publishing},
  address   = {Hannover},
  issn      = {2751-9899 (online)},
  doi       = {10.52825/solarpaces.v1i.678},
  pages     = {9 Seiten},
  year      = {2022},
  abstract  = {In this work, three patent pending calibration methods for heliostat fields of central receiver systems (CRS) developed by the Solar-Institut J{\"u}lich (SIJ) of the FH Aachen University of Applied Sciences are presented. The calibration methods can either operate in a combined mode or in stand-alone mode. The first calibration method, method A, foresees that a camera matrix is placed into the receiver plane where it is subjected to concentrated solar irradiance during a measurement process. The second calibration method, method B, uses an unmanned aerial vehicle (UAV) such as a quadrocopter to automatically fly into the reflected solar irradiance cross-section of one or more heliostats (two variants of method B were tested). The third calibration method, method C, foresees a stereo central camera or multiple stereo cameras installed e.g. on the solar tower whereby the orientations of the heliostats are calculated from the location detection of spherical red markers attached to the heliostats. The most accurate method is method A which has a mean accuracy of 0.17 mrad. The mean accuracy of method B variant 1 is 1.36 mrad and of variant 2 is 1.73 mrad. Method C has a mean accuracy of 15.07 mrad. For method B there is great potential regarding improving the measurement accuracy. For method C the collected data was not sufficient for determining whether or not there is potential for improving the accuracy.},
  language  = {en}
}
@inproceedings{SattlerChicoCaminosAttietal.2020,
  author    = {Sattler, Johannes Christoph and Chico Caminos, Ricardo Alexander and Atti, Vikrama Nagababu and {\"U}rlings, Nicolas and Dutta, Siddharth and Ruiz, Victor and Kalogirou, Soteris and Ktistis, Panayiotis and Agathokleous, Rafaela and Alexopoulos, Spiros and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf},
  title     = {Dynamic simulation tool for a performance evaluation and sensitivity study of a parabolic trough collector system with concrete thermal energy storage},
  series = {AIP Conference Proceedings 2303},
  booktitle = {AIP Conference Proceedings 2303},
  publisher = {American Institute of Physics},
  address   = {Melville, NY},
  issn      = {0094-243X},
  doi       = {10.1063/5.0029277},
  pages     = {160004},
  year      = {2020},
  language  = {de}
}
@inproceedings{SattlerAttiAlexopoulosetal.2022,
  author    = {Sattler, Johannes Christoph and Atti, Vikrama and Alexopoulos, Spiros and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf and Dutta, Siddharth and Kioutsioukis, Ioannis},
  title     = {DNI forecast tool for the smart operation of a parabolic trough collector system with concrete thermal energy storage: Theory, results and outlook},
  series = {SolarPACES conference proceedings},
  booktitle = {SolarPACES conference proceedings},
  number    = {VOL. 1},
  publisher = {TIB Open Publishing},
  address   = {Hannover},
  issn      = {2751-9899 (online)},
  doi       = {10.52825/solarpaces.v1i.731},
  pages     = {9 Seiten},
  year      = {2022},
  abstract  = {This work presents a basic forecast tool for predicting direct normal irradiance (DNI) in hourly resolution, which the Solar-Institut J{\"u}lich (SIJ) is developing within a research project. The DNI forecast data shall be used for a parabolic trough collector (PTC) system with a concrete thermal energy storage (C-TES) located at the company KEAN Soft Drinks Ltd in Limassol, Cyprus. On a daily basis, 24-hour DNI prediction data in hourly resolution shall be automatically produced using free or very low-cost weather forecast data as input. The purpose of the DNI forecast tool is to automatically transfer the DNI forecast data on a daily basis to a main control unit (MCU). The MCU automatically makes a smart decision on the operation mode of the PTC system such as steam production mode and/or C-TES charging mode. The DNI forecast tool was evaluated using historical data of measured DNI from an on-site weather station, which was compared to the DNI forecast data. The DNI forecast tool was tested using data from 56 days between January and March 2022, which included days with a strong variation in DNI due to cloud passages. For the evaluation of the DNI forecast reliability, three categories were created and the forecast data was sorted accordingly. The result was that the DNI forecast tool has a reliability of 71.4 \% based on the tested days. The result fulfils SIJ's aim to achieve a reliability of around 70 \%, but SIJ aims to still improve the DNI forecast quality.},
  language  = {en}
}
@inproceedings{RendonSchwagerGhiasietal.2020,
  author    = {Rendon, Carlos and Schwager, Christian and Ghiasi, Mona and Schmitz, Pascal and Bohang, Fakhri and Caminos, Ricardo Alexander Chico and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf},
  title     = {Modeling and upscaling of a pilot bayonettube reactor for indirect solar mixed methane reforming},
  series = {AIP Conference Proceedings},
  booktitle = {AIP Conference Proceedings},
  number    = {2303},
  doi       = {10.1063/5.0029974},
  pages     = {170012-1 -- 170012-9},
  year      = {2020},
  language  = {en}
}
@inproceedings{RendonDieckmannWeidleetal.2018,
  author    = {Rendon, Carlos and Dieckmann, Simon and Weidle, Mathias and Dersch, J{\"u}rgen and Teixeira Boura, Cristiano Jos{\´e} and Polklas, Thomas and Kuschel, Marcus and Herrmann, Ulf},
  title     = {Retrofitting of existing parabolic trough collector power plants with molten salt tower systems},
  series = {AIP Conference Proceedings},
  volume    = {2033},
  booktitle = {AIP Conference Proceedings},
  number    = {1},
  doi       = {10.1063/1.5067030},
  pages     = {030014-1 -- 030014-8},
  year      = {2018},
  language  = {en}
}
@inproceedings{NiederwestbergSchneiderTeixeiraBouraetal.2022,
  author    = {Niederwestberg, Stefan and Schneider, Falko and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf},
  title     = {Introduction to a direct irradiated transparent tube particle receiver},
  series = {SOLARPACES 2020},
  booktitle = {SOLARPACES 2020},
  number    = {2445 / 1},
  publisher = {AIP conference proceedings / American Institute of Physics},
  address   = {Melville, NY},
  isbn      = {978-0-7354-4195-8},
  issn      = {1551-7616 (online)},
  doi       = {10.1063/5.0086735},
  pages     = {9 Seiten},
  year      = {2022},
  abstract  = {New materials often lead to innovations and advantages in technical applications. This also applies to the particle receiver proposed in this work that deploys high-temperature and scratch resistant transparent ceramics. With this receiver design, particles are heated through direct-contact concentrated solar irradiance while flowing downwards through tubular transparent ceramics from top to bottom. In this paper, the developed particle receiver as well as advantages and disadvantages are described. Investigations on the particle heat-up characteristics from solar irradiance were carried out with DEM simulations which indicate that particle temperatures can reach up to 1200 K. Additionally, a simulation model was set up for investigating the dynamic behavior. A test receiver at laboratory scale has been designed and is currently being built. In upcoming tests, the receiver test rig will be used to validate the simulation results. The design and the measurement equipment is described in this work.},
  language  = {en}
}
@inproceedings{NeumannAdamBackesetal.2021,
  author    = {Neumann, Hannah and Adam, Mario and Backes, Klaus and B{\"o}rner, Martin and Clees, Tanja and Doetsch, Christian and Glaeser, Susanne and Herrmann, Ulf and May, Johanna and Rosenthal, Florian and Sauer, Dirk Uwe and Stadler, Ingo},
  title     = {Development of open educational resources for renewable energy and the energy transition process},
  series = {ISES SWC 2021},
  booktitle = {ISES SWC 2021},
  publisher = {International Solar Energy Society},
  address   = {Freiburg},
  doi       = {10.18086/swc.2021.47.03},
  pages     = {6 Seiten},
  year      = {2021},
  abstract  = {The dissemination of knowledge about renewable energies is understood as a social task with the highest topicality. The transfer of teaching content on renewable energies into digital open educational resources offers the opportunity to significantly accelerate the implementation of the energy transition. Thus, in the here presented project six German universities create open educational resources for the energy transition. These materials are available to the public on the internet under a free license. So far there has been no publicly accessible, editable media that cover entire learning units about renewable energies extensively and in high technical quality. Thus, in this project, the content that remains up-to-date for a longer period is appropriately prepared in terms of media didactics. The materials enable lecturers to provide students with in-depth training about technologies for the energy transition. In a particular way, the created material is also suitable for making the general public knowledgeable about the energy transition with scientifically based material.},
  language  = {en}
}
@inproceedings{MayBreitbachAlexopoulosetal.2019,
  author    = {May, Martin and Breitbach, Gerd and Alexopoulos, Spiros and Latzke, Markus and B{\"a}umer, Klaus and Uhlig, Ralf and S{\"o}hn, Matthias and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf},
  title     = {Experimental facility for investigations of wire mesh absorbers for pressurized gases},
  series = {AIP Conference Proceedings},
  volume    = {2126},
  booktitle = {AIP Conference Proceedings},
  issn      = {0094243X},
  doi       = {10.1063/1.5117547},
  pages     = {030035-1 -- 030035-9},
  year      = {2019},
  language  = {en}
}
@inproceedings{MahdiRendonSchwageretal.2019,
  author    = {Mahdi, Zahra and Rend{\´o}n, Carlos and Schwager, Christian and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf},
  title     = {Novel concept for indirect solar-heated methane reforming},
  series = {AIP Conference Proceedings},
  volume    = {2126},
  booktitle = {AIP Conference Proceedings},
  publisher = {AIP Publishing},
  address   = {Melville, NY},
  issn      = {0094-243X},
  doi       = {10.1063/1.5117694},
  pages     = {180014-1 -- 180014-7},
  year      = {2019},
  language  = {en}
}
@inproceedings{MahdiDerschSchmitzetal.2022,
  author    = {Mahdi, Zahra and Dersch, J{\"u}rgen and Schmitz, Pascal and Dieckmann, Simon and Caminos, Ricardo Alexander Chico and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf and Schwager, Christian and Schmitz, Mark and Gielen, Hans and Gedle, Yibekal and B{\"u}scher, Rauno},
  title     = {Technical assessment of Brayton cycle heat pumps for the integration in hybrid PV-CSP power plants},
  series = {SOLARPACES 2020},
  booktitle = {SOLARPACES 2020},
  number    = {2445 / 1},
  publisher = {AIP conference proceedings / American Institute of Physics},
  address   = {Melville, NY},
  isbn      = {978-0-7354-4195-8},
  issn      = {1551-7616 (online)},
  doi       = {10.1063/5.0086269},
  pages     = {11 Seiten},
  year      = {2022},
  abstract  = {The hybridization of Concentrated Solar Power (CSP) and Photovoltaics (PV) systems is a promising approach to reduce costs of solar power plants, while increasing dispatchability and flexibility of power generation. High temperature heat pumps (HT HP) can be utilized to boost the salt temperature in the thermal energy storage (TES) of a Parabolic Trough Collector (PTC) system from 385 °C up to 565 °C. A PV field can supply the power for the HT HP, thus effectively storing the PV power as thermal energy. Besides cost-efficiently storing energy from the PV field, the power block efficiency of the overall system is improved due to the higher steam parameters. This paper presents a technical assessment of Brayton cycle heat pumps to be integrated in hybrid PV-CSP power plants. As a first step, a theoretical analysis was carried out to find the most suitable working fluid. The analysis included the fluids Air, Argon (Ar), Nitrogen (N2) and Carbon dioxide (CO2). N2 has been chosen as the optimal working fluid for the system. After the selection of the ideal working medium, different concepts for the arrangement of a HT HP in a PV-CSP hybrid power plant were developed and simulated in EBSILON®Professional. The concepts were evaluated technically by comparing the number of components required, pressure losses and coefficient of performance (COP).},
  language  = {en}
}
@inproceedings{LuepfertHerrmannPriceetal.2004,
  author    = {L{\"u}pfert, E. and Herrmann, Ulf and Price, Henry and Zarza, E. and Kistener, R.},
  title     = {Towards Standard Performance Analysis for Parabolic Trough Collector Fields},
  series = {12th International Symposium Solar Power and Chemical Energy Systems, October 6-8, 2004, Oaxaca Mexico ; SolarPACES International Symposium, 12},
  booktitle = {12th International Symposium Solar Power and Chemical Energy Systems, October 6-8, 2004, Oaxaca Mexico ; SolarPACES International Symposium, 12},
  editor    = {Ramos, C.},
  publisher = {Instituto de Investigaciones Electricas},
  address   = {[s.l.]},
  isbn      = {968-6114-18-1},
  year      = {2004},
  language  = {en}
}
@inproceedings{LahrsKrisamHerrmann2023,
  author    = {Lahrs, Lennart and Krisam, Pierre and Herrmann, Ulf},
  title     = {Envisioning a collaborative energy system planning platform for the energy transition at the district level},
  series = {The 36th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems},
  booktitle = {The 36th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems},
  publisher = {Procedings of ECOS 2023},
  doi       = {10.52202/069564-0284},
  pages     = {3163 -- 3170},
  year      = {2023},
  abstract  = {Residential and commercial buildings account for more than one-third of global energy-related greenhouse gas emissions. Integrated multi-energy systems at the district level are a promising way to reduce greenhouse gas emissions by exploiting economies of scale and synergies between energy sources. Planning district energy systems comes with many challenges in an ever-changing environment. Computational modelling established itself as the state-of-the-art method for district energy system planning. Unfortunately, it is still cumbersome to combine standalone models to generate insights that surpass their original purpose. Ideally, planning processes could be solved by using modular tools that easily incorporate the variety of competing and complementing computational models. Our contribution is a vision for a collaborative development and application platform for multi-energy system planning tools at the district level. We present challenges of district energy system planning identified in the literature and evaluate whether this platform can help to overcome these challenges. Further, we propose a toolkit that represents the core technical elements of the platform. Lastly, we discuss community management and its relevance for the success of projects with collaboration and knowledge sharing at their core.},
  language  = {en}
}
@inproceedings{KronhardtAlexopoulosReisseletal.2015,
  author    = {Kronhardt, Valentina and Alexopoulos, Spiros and Reißel, Martin and Latzke, Markus and Rendon, C. and Sattler, Johannes, Christoph and Herrmann, Ulf},
  title     = {Simulation of operational management for the Solar Thermal Test and Demonstration Power Plant J{\"u}lich using optimized control strategies of the storage system},
  series = {Energy procedia},
  booktitle = {Energy procedia},
  issn      = {1876-6102},
  pages     = {1 -- 6},
  year      = {2015},
  language  = {en}
}
@inproceedings{KellyHerrmannHale2001,
  author    = {Kelly, Bruce and Herrmann, Ulf and Hale, M.-J.},
  title     = {Optimization Studies for Integrated Solar Combined Cycle Systems},
  series = {Solar engineering 2001 : proceedings of the International Solar Energy Conference ; presented at the 2001 International Solar Energy Conference, a part of Forum 2001 - Solar energy: the power to choose, April 21 - 25, 2001, Washington, D.C.},
  booktitle = {Solar engineering 2001 : proceedings of the International Solar Energy Conference ; presented at the 2001 International Solar Energy Conference, a part of Forum 2001 - Solar energy: the power to choose, April 21 - 25, 2001, Washington, D.C.},
  publisher = {ASME},
  address   = {New York, NY},
  isbn      = {0-7918-1670-2},
  pages     = {393 -- 398},
  year      = {2001},
  language  = {en}
}
@inproceedings{JanotteFecklerKoetteretal.2014,
  author    = {Janotte, N. and Feckler, G. and K{\"o}tter, Jens and Decker, Stefan and Herrmann, Ulf and Schmitz, Mark and L{\"u}pfert, E.},
  title     = {Dynamic performance evaluation of the HelioTrough® collector demonstration loop : towards a new benchmark in parabolic trough qualification},
  series = {SolarPACES International Conference 2013, Las Vegas, Nevada, USA, 17 - 20 September 2013 : [proceedings]. - Pt. 1. - (Energy procedia ; 49)},
  booktitle = {SolarPACES International Conference 2013, Las Vegas, Nevada, USA, 17 - 20 September 2013 : [proceedings]. - Pt. 1. - (Energy procedia ; 49)},
  publisher = {Curran},
  address   = {Red Hook, NY},
  isbn      = {978-1-63266-904-9},
  issn      = {1876-6102},
  doi       = {10.1016/j.egypro.2014.03.012},
  pages     = {109 -- 117},
  year      = {2014},
  language  = {en}
}
@inproceedings{HerrmannWorringerGraeteretal.2006,
  author    = {Herrmann, Ulf and Worringer, S. and Graeter, F. and Nava, P.},
  title     = {Three Years of Operation Experience of the SKAL-ET Collector Loop at SEGS V},
  series = {13th International Symposium Concentrated Solar Power and Chemical Energy Technologies, June 20 - 23, 2006, Seville, Spain},
  booktitle = {13th International Symposium Concentrated Solar Power and Chemical Energy Technologies, June 20 - 23, 2006, Seville, Spain},
  editor    = {Romero, Manuel},
  publisher = {SolarPACES [u.a.]},
  address   = {[s.l.]},
  isbn      = {84-7834-519-1},
  pages     = {1 CD-ROM},
  year      = {2006},
  language  = {en}
}
@inproceedings{HerrmannVorbruggNava2009,
  author    = {Herrmann, Ulf and Vorbrugg, O. and Nava, P.},
  title     = {Construction and Commissioning Process of the Andasol Solar Field},
  series = {SolarPACES 2009 : electricity, fuels and clean water powered by the sun ; 15 - 18 September 2009, Berlin, Germany ; the 15th SolarPACES conference ; proceedings},
  booktitle = {SolarPACES 2009 : electricity, fuels and clean water powered by the sun ; 15 - 18 September 2009, Berlin, Germany ; the 15th SolarPACES conference ; proceedings},
  publisher = {Deutsches Zentrum f{\"u}r Luft- u. Raumfahrt},
  address   = {Stuttgart},
  isbn      = {978-3-00-028755-8},
  pages     = {1 CD-ROM},
  year      = {2009},
  language  = {en}
}
@inproceedings{HerrmannRheinlaenderLippke1997,
  author    = {Herrmann, Ulf and Rheinl{\"a}nder, J. and Lippke, F.},
  title     = {Solar Fields for Direct Steam Generation in Parabolic Trough Collectors},
  series = {Components, tools, facilities and measurement techniques. - (Solar thermal concentrating technologies : proceedings of the 8th international symposium, October, 6 - 11, 1996, K{\"o}ln, Germany ; Vol. 2)},
  booktitle = {Components, tools, facilities and measurement techniques. - (Solar thermal concentrating technologies : proceedings of the 8th international symposium, October, 6 - 11, 1996, K{\"o}ln, Germany ; Vol. 2)},
  editor    = {Becker, Manfred},
  publisher = {M{\"u}ller},
  address   = {Heidelberg},
  isbn      = {3-7880-7616-X},
  pages     = {815 -- 834},
  year      = {1997},
  language  = {en}
}