@inproceedings{BlankeSchmidtGoettscheetal.2022,
  author    = {Blanke, Tobias and Schmidt, Katharina S. and G{\"o}ttsche, Joachim and D{\"o}ring, Bernd and Frisch, J{\´e}r{\^o}me and van Treeck, Christoph},
  title     = {Time series aggregation for energy system design: review and extension of modelling seasonal storages},
  series = {Energy Informatics},
  volume    = {5},
  booktitle = {Energy Informatics},
  number    = {1, Article number: 17},
  editor    = {Weidlich, Anke and Neumann, Dirk and Gust, Gunther and Staudt, Philipp and Sch{\"a}fer, Mirko},
  publisher = {Springer Nature},
  issn      = {2520-8942},
  doi       = {10.1186/s42162-022-00208-5},
  pages     = {14 Seiten},
  year      = {2022},
  abstract  = {Using optimization to design a renewable energy system has become a computationally demanding task as the high temporal fluctuations of demand and supply arise within the considered time series. The aggregation of typical operation periods has become a popular method to reduce effort. These operation periods are modelled independently and cannot interact in most cases. Consequently, seasonal storage is not reproducible. This inability can lead to a significant error, especially for energy systems with a high share of fluctuating renewable energy. The previous paper, "Time series aggregation for energy system design: Modeling seasonal storage", has developed a seasonal storage model to address this issue. Simultaneously, the paper "Optimal design of multi-energy systems with seasonal storage" has developed a different approach. This paper aims to review these models and extend the first model. The extension is a mathematical reformulation to decrease the number of variables and constraints. Furthermore, it aims to reduce the calculation time while achieving the same results.},
  language  = {en}
}
@inproceedings{GoettscheHoffschmidtSchmitzetal.2008,
  author    = {G{\"o}ttsche, Joachim and Hoffschmidt, Bernhard and Schmitz, S. and Sauerborn, Markus and Rebholz, C. and Iffland, D. and Badst{\"u}bner, R. and Buck, R. and Teufel, E.},
  title     = {Test of a mini-mirror array for solar concentrating systems},
  series = {EuroSun 2008 : 1st International Conference on Solar Heating, Cooling and Buildings ; 7th - 10th October 2008, Lisbon, Portugal : key lectures / ISES, International Solar Energy Society. Vol. 1},
  booktitle = {EuroSun 2008 : 1st International Conference on Solar Heating, Cooling and Buildings ; 7th - 10th October 2008, Lisbon, Portugal : key lectures / ISES, International Solar Energy Society. Vol. 1},
  publisher = {Sociedade Portuguesa De Energia Solar (SPES)},
  address   = {Lissabon},
  isbn      = {978-1-61782-228-5},
  pages     = {1242 -- 1250},
  year      = {2008},
  language  = {en}
}
@inproceedings{HerrmannKellyPrice2002,
  author    = {Herrmann, Ulf and Kelly, Bruce and Price, Henry},
  title     = {Two Tank Molten Salt Storage for Parabolic Trough Solar Power Plants},
  series = {Proceedings of the 11th SolarPACES International Symposium on Concentrated Solar Power and Chemical Energy Technologies : September 4 - 6, 2002, Zurich, Switzerland / Paul Scherrer Institut, PSI; ETH, Eidgen{\"o}ssische Technische Hochschule Z{\"u}rich},
  booktitle = {Proceedings of the 11th SolarPACES International Symposium on Concentrated Solar Power and Chemical Energy Technologies : September 4 - 6, 2002, Zurich, Switzerland / Paul Scherrer Institut, PSI; ETH, Eidgen{\"o}ssische Technische Hochschule Z{\"u}rich},
  editor    = {Steinfeld, Aldo},
  publisher = {Paul Scherrer Inst.},
  address   = {Villingen},
  isbn      = {3-9521409-3-7},
  pages     = {517 -- 524},
  year      = {2002},
  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{SchwagerAngeleSchwarzboezletal.2023,
  author    = {Schwager, Christian and Angele, Florian and Schwarzb{\"o}zl, Peter and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf},
  title     = {Model predictive assistance for operational decision making in molten salt receiver systems},
  series = {SolarPACES: Solar Power \& Chemical Energy Systems},
  booktitle = {SolarPACES: Solar Power \& Chemical Energy Systems},
  number    = {2815 / 1},
  publisher = {AIP conference proceedings / American Institute of Physics},
  address   = {Melville, NY},
  isbn      = {978-0-7354-4623-6},
  issn      = {1551-7616 (online)},
  doi       = {10.1063/5.0151514},
  pages     = {8 Seiten},
  year      = {2023},
  abstract  = {Despite the challenges of pioneering molten salt towers (MST), it remains the leading technology in central receiver power plants today, thanks to cost effective storage integration and high cost reduction potential. The limited controllability in volatile solar conditions can cause significant losses, which are difficult to estimate without comprehensive modeling [1]. This paper presents a Methodology to generate predictions of the dynamic behavior of the receiver system as part of an operating assistance system (OAS). Based on this, it delivers proposals if and when to drain and refill the receiver during a cloudy period in order maximize the net yield and quantifies the amount of net electricity gained by this. After prior analysis with a detailed dynamic two-phase model of the entire receiver system, two different reduced modeling approaches where developed and implemented in the OAS. A tailored decision algorithm utilizes both models to deliver the desired predictions efficiently and with appropriate accuracy.},
  language  = {en}
}
@article{PeereBlanke2022,
  author    = {Peere, Wouter and Blanke, Tobias},
  title     = {GHEtool: An open-source tool for borefield sizing in Python},
  series = {Journal of Open Source Software},
  volume    = {7},
  journal   = {Journal of Open Source Software},
  number    = {76},
  editor    = {Vernon, Chris},
  issn      = {2475-9066},
  doi       = {10.21105/joss.04406},
  pages     = {1 -- 4, 4406},
  year      = {2022},
  abstract  = {GHEtool is a Python package that contains all the functionalities needed to deal with borefield design. It is developed for both researchers and practitioners. The core of this package is the automated sizing of borefield under different conditions. The sizing of a borefield is typically slow due to the high complexity of the mathematical background. Because this tool has a lot of precalculated data, GHEtool can size a borefield in the order of tenths of milliseconds. This sizing typically takes the order of minutes. Therefore, this tool is suited for being implemented in typical workflows where iterations are required. GHEtool also comes with a graphical user interface (GUI). This GUI is prebuilt as an exe-file because this provides access to all the functionalities without coding. A setup to install the GUI at the user-defined place is also implemented and available at: https://www.mech.kuleuven.be/en/tme/research/thermal_systems/tools/ghetool.},
  language  = {en}
}
@inproceedings{SchwagerAngeleNourietal.2022,
  author    = {Schwager, Christian and Angele, Florian and Nouri, Bijan and Schwarzb{\"o}zl, Peter and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf},
  title     = {Impact of DNI forecast quality on performance prediction for a commercial scale solar tower: Application of nowcasting DNI maps to dynamic solar tower simulation},
  series = {SolarPACES 2022 conference proceedings},
  booktitle = {SolarPACES 2022 conference proceedings},
  number    = {1},
  publisher = {TIB Open Publishing},
  address   = {Hannover},
  issn      = {2751-9899 (online)},
  doi       = {10.52825/solarpaces.v1i.675},
  pages     = {9 Seiten},
  year      = {2022},
  abstract  = {Concerning current efforts to improve operational efficiency and to lower overall costs of concentrating solar power (CSP) plants with prediction-based algorithms, this study investigates the quality and uncertainty of nowcasting data regarding the implications for process predictions. DNI (direct normal irradiation) maps from an all-sky imager-based nowcasting system are applied to a dynamic prediction model coupled with ray tracing. The results underline the need for high-resolution DNI maps in order to predict net yield and receiver outlet temperature realistically. Furthermore, based on a statistical uncertainty analysis, a correlation is developed, which allows for predicting the uncertainty of the net power prediction based on the corresponding DNI forecast uncertainty. However, the study reveals significant prediction errors and the demand for further improvement in the accuracy at which local shadings are forecasted.},
  language  = {en}
}
@inproceedings{SchulteSchwagerFrantzetal.2022,
  author    = {Schulte, Jonas and Schwager, Christian and Frantz, Cathy and Schloms, Felix and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf},
  title     = {Control concept for a molten salt receiver in star design: Development, optimization and testing with cloud passage scenarios},
  series = {SolarPACES 2022 conference proceedings},
  booktitle = {SolarPACES 2022 conference proceedings},
  number    = {1},
  publisher = {TIB Open Publishing},
  address   = {Hannover},
  issn      = {2751-9899 (online)},
  doi       = {10.52825/solarpaces.v1i.693},
  pages     = {9 Seiten},
  year      = {2022},
  abstract  = {A promising approach to reduce the system costs of molten salt solar receivers is to enable the irradiation of the absorber tubes on both sides. The star design is an innovative receiver design, pursuing this approach. The unconventional design leads to new challenges in controlling the system. This paper presents a control concept for a molten salt receiver system in star design. The control parameters are optimized in a defined test cycle by minimizing a cost function. The control concept is tested in realistic cloud passage scenarios based on real weather data. During these tests, the control system showed no sign of unstable behavior, but to perform sufficiently in every scenario further research and development like integrating Model Predictive Controls (MPCs) need to be done. The presented concept is a starting point to do so.},
  language  = {en}
}
@inproceedings{LatzkeAlexopoulosKronhardtetal.2015,
  author    = {Latzke, Markus and Alexopoulos, Spiros and Kronhardt, Valentina and Rend{\´o}n, Carlos and Sattler, Johannes Christoph},
  title     = {Comparison of Potential Sites in China for Erecting a Hybrid Solar Tower Power Plant with Air Receiver},
  series = {Energy Procedia},
  booktitle = {Energy Procedia},
  issn      = {1876-6102},
  doi       = {10.1016/j.egypro.2015.03.142},
  pages     = {1327 -- 1334},
  year      = {2015},
  language  = {en}
}
@inproceedings{BaumannTeixeiraBouraEcksteinetal.2011,
  author    = {Baumann, Torsten and Teixeira Boura, Cristiano Jos{\´e} and Eckstein, Julian and Felinks, Jan and G{\"o}ttsche, Joachim and Hoffschmidt, Bernhard and Schmitz, Stefan and Zunft, Stefan},
  title     = {Air-sand heat exchanger},
  series = {6th International Renewable Energy Storage Conference (IRES 2011) : November 28 - 30, 2011, bcc Berlin Congress Center, Berlin, Germany / EUROSOLAR ...},
  booktitle = {6th International Renewable Energy Storage Conference (IRES 2011) : November 28 - 30, 2011, bcc Berlin Congress Center, Berlin, Germany / EUROSOLAR ...},
  publisher = {Eurosolar},
  address   = {Bonn},
  pages     = {1 CD-ROM},
  year      = {2011},
  language  = {de}
}
@inproceedings{ChicoCaminosSchmitzAttietal.2022,
  author    = {Chico Caminos, Ricardo Alexander and Schmitz, Pascal and Atti, Vikrama and Mahdi, Zahra and Teixeira Boura, Cristiano Jos{\´e} and Sattler, Johannes Christoph and Herrmann, Ulf and Hilger, Patrick and Dieckmann, Simon},
  title     = {Development of a micro heliostat and optical qualification assessment with a 3D laser scanning method},
  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       = {10.1063/5.0086262},
  pages     = {8 Seiten},
  year      = {2022},
  abstract  = {The Solar-Institut J{\"u}lich (SIJ) and the companies Hilger GmbH and Heliokon GmbH from Germany have developed a small-scale cost-effective heliostat, called "micro heliostat". Micro heliostats can be deployed in small-scale concentrated solar power (CSP) plants to concentrate the sun's radiation for electricity generation, space or domestic water heating or industrial process heat. In contrast to conventional heliostats, the special feature of a micro heliostat is that it consists of dozens of parallel-moving, interconnected, rotatable mirror facets. The mirror facets array is fixed inside a box-shaped module and is protected from weathering and wind forces by a transparent glass cover. The choice of the building materials for the box, tracking mechanism and mirrors is largely dependent on the selected production process and the intended application of the micro heliostat. Special attention was paid to the material of the tracking mechanism as this has a direct influence on the accuracy of the micro heliostat. The choice of materials for the mirror support structure and the tracking mechanism is made in favor of plastic molded parts. A qualification assessment method has been developed by the SIJ in which a 3D laser scanner is used in combination with a coordinate measuring machine (CMM). For the validation of this assessment method, a single mirror facet was scanned and the slope deviation was computed.},
  language  = {en}
}
@inproceedings{BaumannTeixeiraBouraGoettscheetal.2011,
  author    = {Baumann, Torsten and Teixeira Boura, Cristiano Jos{\´e} and G{\"o}ttsche, Joachim and Hoffschmidt, Bernhard and Schmitz, Stefan and Zunft, Stefan},
  title     = {Air-sand heat exchanger: materials and flow properties},
  series = {SolarPACES 2011 : concentrating solar power and chemical energy systems : 20 - 23 September, 2011, Granada, Spain},
  booktitle = {SolarPACES 2011 : concentrating solar power and chemical energy systems : 20 - 23 September, 2011, Granada, Spain},
  address   = {Granada},
  pages     = {1 CD-ROM},
  year      = {2011},
  language  = {en}
}
@inproceedings{FrickeZiolkoAnthrakidisetal.2011,
  author    = {Fricke, Barbara and Ziolko, C. and Anthrakidis, Anette and Alexopoulos, Spiros and Hoffschmidt, Bernhard and Dillig, M. and Giese, F.},
  title     = {InnoSol - life cycle analysis of solar power tower plants},
  series = {SolarPACES 2011 : concentrating solar power and chemical energy systems : 20 - 23 September, 2011, Granada, Spain},
  booktitle = {SolarPACES 2011 : concentrating solar power and chemical energy systems : 20 - 23 September, 2011, Granada, Spain},
  address   = {Granada},
  pages     = {1 CD-ROM},
  year      = {2011},
  language  = {en}
}
@inproceedings{GorzalkaDahlkeGoettscheetal.2018,
  author    = {Gorzalka, Philip and Dahlke, Dennis and G{\"o}ttsche, Joachim and Israel, Martin and Patel, Dhruvkumar and Prahl, Christoph and Schmiedt, Jacob Estevam and Frommholz, Dirk and Hoffschmidt, Bernhard and Linkiewicz, Magdalena},
  title     = {Building Tomograph-From Remote Sensing Data of Existing Buildings to Building Energy Simulation Input},
  series = {EBC, Annex 71, Fifth expert meeting, October 17-19, 2018, Innsbruck, Austria},
  booktitle = {EBC, Annex 71, Fifth expert meeting, October 17-19, 2018, Innsbruck, Austria},
  pages     = {17 Seiten},
  year      = {2018},
  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 = {ECOS 2023. The 36th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems},
  booktitle = {ECOS 2023. 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}
}
@article{HerrmannKearney2002,
  author    = {Herrmann, Ulf and Kearney, David W.},
  title     = {Survey of Thermal Energy Storage for Parabolic Trough Power Plants},
  series = {Journal of Solar Energy Engineering},
  volume    = {124},
  journal   = {Journal of Solar Energy Engineering},
  number    = {2},
  issn      = {1528-8986 (Online)},
  doi       = {10.1115/1.1467601},
  pages     = {145 -- 152},
  year      = {2002},
  language  = {en}
}
@inproceedings{SauerbornLiebenstundRaueetal.2017,
  author    = {Sauerborn, Markus and Liebenstund, Lena and Raue, Markus and Mang, Thomas and Herrmann, Ulf and Dueing, Andreas},
  title     = {Analytic method for material aging and quality analyzing to forecast long time stability of plastic micro heliostat components},
  series = {AIP Conference Proceedings},
  volume    = {1850},
  booktitle = {AIP Conference Proceedings},
  number    = {1},
  doi       = {10.1063/1.4984388},
  pages     = {030045-1 -- 030045-8},
  year      = {2017},
  language  = {en}
}
@article{HerrmannLippke1999,
  author    = {Herrmann, Ulf and Lippke, F.},
  title     = {The influence of transients on the design of DSG solar fields},
  series = {Journal de Physique IV : proceedings},
  volume    = {9},
  journal   = {Journal de Physique IV : proceedings},
  number    = {PR3},
  isbn      = {2-86883-402-7},
  issn      = {1764-7177 (Online)},
  doi       = {10.1051/jp4:1999377},
  pages     = {489 -- 494},
  year      = {1999},
  language  = {en}
}
@inproceedings{WarerkarSchmitzGoettscheetal.2009,
  author    = {Warerkar, Shashikant and Schmitz, Stefan and G{\"o}ttsche, Joachim and Hoffschmidt, Bernhard and Reißel, Martin and Tamme, Rainer},
  title     = {Air-sand heat exchanger for high-temperature storage},
  series = {Proceedings of the ASME 3rd International Conference on Energy Sustainability : July 19 - 23, 2009, San Francisco, California, USA. Vol. 2},
  booktitle = {Proceedings of the ASME 3rd International Conference on Energy Sustainability : July 19 - 23, 2009, San Francisco, California, USA. Vol. 2},
  publisher = {ASME},
  address   = {New York, NY},
  isbn      = {978-0-7918-4890-6},
  pages     = {655 -- 661},
  year      = {2009},
  language  = {en}
}
@inproceedings{SchornWeisAnthrakidisetal.2016,
  author    = {Schorn, Christian and Weis, Fabian and Anthrakidis, Anette and Schwarzer, Klemens and Schmitz, Mark and Herrmann, Ulf},
  title     = {Entwicklung und Bewertung eines Parabolrinnenkollektors zur Prozessw{\"a}rmebereitstellung},
  series = {26. Symposium Thermische Solarenergie, 20.-22.04.2016 in Bad Staffelstein},
  booktitle = {26. Symposium Thermische Solarenergie, 20.-22.04.2016 in Bad Staffelstein},
  pages     = {1 -- 13},
  year      = {2016},
  language  = {de}
}