@inproceedings{SauerbornKlimekHoffschmidtetal.2012,
  author    = {Sauerborn, Markus and Klimek, J. and Hoffschmidt, Bernhard and Essen, H. and Sieger, S. and Biegel, G. and G{\"o}ttsche, Joachim and Hilger, Patrick},
  title     = {Eurosun 2012 : radar technology for heliostat posititon control},
  series = {Eurosun 2012 : Solar energy for a brighter future : conference proceedings : Rijeka, 18.-22.09.2012},
  booktitle = {Eurosun 2012 : Solar energy for a brighter future : conference proceedings : Rijeka, 18.-22.09.2012},
  address   = {Rijeka},
  pages     = {ID 80},
  year      = {2012},
  language  = {en}
}
@inproceedings{GoettscheSchwarzerRoetheretal.2009,
  author    = {G{\"o}ttsche, Joachim and Schwarzer, Klemens and R{\"o}ther, Sascha and Jellinghaus, Sabine and Helten, G. and Wittmann, R.},
  title     = {Efficient daylighting, heating and shading with rooflight heliostats},
  series = {Renewables in a changing climate : from Nano to Urban Scale : CISBAT 2009 : 2-3 September 2009, EPFL, Lausanne, Switzerland : proceedings},
  booktitle = {Renewables in a changing climate : from Nano to Urban Scale : CISBAT 2009 : 2-3 September 2009, EPFL, Lausanne, Switzerland : proceedings},
  publisher = {Ecole Polytechnique F{\´e}d{\´e}rale de Lausanne},
  address   = {Lausanne},
  pages     = {243 -- 246},
  year      = {2009},
  language  = {en}
}
@article{BlankeHagenkampDoeringetal.2021,
  author    = {Blanke, Tobias and Hagenkamp, Markus and D{\"o}ring, Bernd and G{\"o}ttsche, Joachim and Reger, Vitali and Kuhnhenne, Markus},
  title     = {Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates},
  series = {Geothermal Energy},
  volume    = {9},
  journal   = {Geothermal Energy},
  number    = {Article number: 19},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {2195-9706},
  doi       = {10.1186/s40517-021-00201-3},
  pages     = {23 Seiten},
  year      = {2021},
  abstract  = {Previous studies optimized the dimensions of coaxial heat exchangers using constant mass fow rates as a boundary condition. They show a thermal optimal circular ring width of nearly zero. Hydraulically optimal is an inner to outer pipe radius ratio of 0.65 for turbulent and 0.68 for laminar fow types. In contrast, in this study, fow conditions in the circular ring are kept constant (a set of fxed Reynolds numbers) during optimization. This approach ensures fxed fow conditions and prevents inappropriately high or low mass fow rates. The optimization is carried out for three objectives: Maximum energy gain, minimum hydraulic efort and eventually optimum net-exergy balance. The optimization changes the inner pipe radius and mass fow rate but not the Reynolds number of the circular ring. The thermal calculations base on Hellstr{\"o}m's borehole resistance and the hydraulic optimization on individually calculated linear loss of head coefcients. Increasing the inner pipe radius results in decreased hydraulic losses in the inner pipe but increased losses in the circular ring. The net-exergy diference is a key performance indicator and combines thermal and hydraulic calculations. It is the difference between thermal exergy fux and hydraulic efort. The Reynolds number in the circular ring is instead of the mass fow rate constant during all optimizations. The result from a thermal perspective is an optimal width of the circular ring of nearly zero. The hydraulically optimal inner pipe radius is 54\% of the outer pipe radius for laminar fow and 60\% for turbulent fow scenarios. Net-exergetic optimization shows a predominant infuence of hydraulic losses, especially for small temperature gains. The exact result depends on the earth's thermal properties and the fow type. Conclusively, coaxial geothermal probes' design should focus on the hydraulic optimum and take the thermal optimum as a secondary criterion due to the dominating hydraulics.},
  language  = {en}
}
@article{GoettscheSchwarzerRoetheretal.2009,
  author    = {G{\"o}ttsche, Joachim and Schwarzer, Klemens and R{\"o}ther, S. and Jellinghaus, Sabine},
  title     = {Efficient daylighting, heating and shading with rooflight heliostats},
  series = {Conference Internationale Energie Solaire et Batiment},
  journal   = {Conference Internationale Energie Solaire et Batiment},
  publisher = {EPFL},
  address   = {Lausanne},
  pages     = {243 -- 248},
  year      = {2009},
  language  = {en}
}
@article{GoettscheGabryschSchilleretal.2004,
  author    = {G{\"o}ttsche, Joachim and Gabrysch, K. and Schiller, H. and Kauert, B. and Schwarzer, Klemens},
  title     = {Energetic Effects of demand - controlled ventilation retrofitting in a biochemical laboratory building},
  series = {AIVC publications [Elektronische Ressource] / Air Infiltration and Ventilation Centre},
  journal   = {AIVC publications [Elektronische Ressource] / Air Infiltration and Ventilation Centre},
  publisher = {INIVE EEIG},
  address   = {Brussels},
  pages     = {50},
  year      = {2004},
  language  = {en}
}
@inproceedings{AchenbachGeimerLynenetal.2012,
  author    = {Achenbach, Timm and Geimer, Konstantin and Lynen, Arthur and G{\"o}ttsche, Joachim and Hoffschmidt, Bernhard},
  title     = {Simulation of thermo-mechanical processes in open volumetric absorber modules},
  series = {SolarPaces 2012 : concentrating solar power and chemical energy systems : Sept. 11 - 14 2012, Marrakech, Marokko},
  booktitle = {SolarPaces 2012 : concentrating solar power and chemical energy systems : Sept. 11 - 14 2012, Marrakech, Marokko},
  pages     = {1 -- 8},
  year      = {2012},
  language  = {en}
}
@incollection{HoffschmidtAlexopoulosGoettscheetal.2012,
  author    = {Hoffschmidt, Bernhard and Alexopoulos, Spiros and G{\"o}ttsche, Joachim and Sauerborn, Markus},
  title     = {High concentration solar collectors},
  series = {Comprehensive renewable energy / ed. Ali Sayigh. Vol. 3: Solar thermal systems: components and applications},
  volume    = {3},
  booktitle = {Comprehensive renewable energy / ed. Ali Sayigh. Vol. 3: Solar thermal systems: components and applications},
  publisher = {Elsevier},
  address   = {Amsterdam},
  isbn      = {978-0-08-087873-7},
  doi       = {10.1016/B978-0-08-087872-0.00306-1},
  pages     = {165 -- 209},
  year      = {2012},
  abstract  = {Solar thermal concentrated power is an emerging technology that provides clean electricity for the growing energy market. To the solar thermal concentrated power plant systems belong the parabolic trough, the Fresnel collector, the solar dish, and the central receiver system. For high-concentration solar collector systems, optical and thermal analysis is essential. There exist a number of measurement techniques and systems for the optical and thermal characterization of the efficiency of solar thermal concentrated systems. For each system, structure, components, and specific characteristics types are described. The chapter presents additionally an outline for the calculation of system performance and operation and maintenance topics. One main focus is set to the models of components and their construction details as well as different types on the market. In the later part of this chapter, different criteria for the choice of technology are analyzed in detail.},
  language  = {en}
}
@article{GoettscheReillyWittwer1991,
  author    = {G{\"o}ttsche, Joachim and Reilly, S. and Wittwer, Volker},
  title     = {Advanced window systems and building energy performance / S. Reilly ; J. G{\"o}ttsche ; V. Wittwer},
  series = {Solar World Congress, 1991 : proceedings of the biennial congress of the International Solar Energy Society, Denver, Colorado, USA, 19-23 August 1991 / ed. by M. E. Arden ...},
  journal   = {Solar World Congress, 1991 : proceedings of the biennial congress of the International Solar Energy Society, Denver, Colorado, USA, 19-23 August 1991 / ed. by M. E. Arden ...},
  publisher = {Pergamon Press},
  address   = {Oxford [u.a.]},
  isbn      = {0-08-041690-X},
  pages     = {3211 -- 3216},
  year      = {1991},
  language  = {en}
}
@inproceedings{WarerkarSchmitzGoettscheetal.2008,
  author    = {Warerkar, S. and Schmitz, S. and G{\"o}ttsche, Joachim and Hoffschmidt, Bernhard and Tamme, R.},
  title     = {Performance analysis of an air-sand heat exchanger prototype for high-temperature storage},
  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     = {2215 -- 2222},
  year      = {2008},
  language  = {en}
}
@article{WarerkarSchmitzGoettscheetal.2011,
  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 = {Journal of Solar Energy Engineering. 133 (2011), H. 2},
  journal   = {Journal of Solar Energy Engineering. 133 (2011), H. 2},
  publisher = {ASME},
  address   = {New York},
  isbn      = {0199-6231},
  pages     = {021010},
  year      = {2011},
  language  = {en}
}
@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{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{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}
}
@article{GoettscheAlexopoulosDuemmleretal.2019,
  author    = {G{\"o}ttsche, Joachim and Alexopoulos, Spiros and D{\"u}mmler, Andreas and Maddineni, S. K.},
  title     = {Multi-Mirror Array Calculations With Optical Error},
  pages     = {1 -- 6},
  year      = {2019},
  abstract  = {The optical performance of a 2-axis solar concentrator was simulated with the COMSOL Multiphysics® software. The concentrator consists of a mirror array, which was created using the application builder. The mirror facets are preconfigured to form a focal point. During tracking all mirrors are moved simultaneously in a coupled mode by 2 motors in two axes, in order to keep the system in focus with the moving sun. Optical errors on each reflecting surface were implemented in combination with the solar angular cone of ± 4.65 mrad. As a result, the intercept factor of solar radiation that is available to the receiver was calculated as a function of the transversal and longitudinal angles of incidence. In addition, the intensity distribution on the receiver plane was calculated as a function of the incidence angles.},
  language  = {en}
}
@inproceedings{BaumannTeixeiraBouraEcksteinetal.2012,
  author    = {Baumann, Torsten and Teixeira Boura, Cristiano Jos{\´e} and Eckstein, Julian and Dabrowski, Jan and G{\"o}ttsche, Joachim and Hoffschmidt, Bernhard and Schmitz, Stefan and Zunft, Stefan},
  title     = {Properties of bulk materials for high-temperature air-sand heat exchangers},
  series = {30th ISES Biennial Solar World Congress 2011 : Kassel, Germany, 28 August - 2 September 2011. Vol. 2},
  booktitle = {30th ISES Biennial Solar World Congress 2011 : Kassel, Germany, 28 August - 2 September 2011. Vol. 2},
  publisher = {Curran},
  address   = {Red Hook, NY},
  organization    = {International Solar Energy Society},
  isbn      = {978-1-61839-364-7},
  pages     = {1270 -- 1278},
  year      = {2012},
  language  = {en}
}
@inproceedings{GoettscheHinschWittwer1992,
  author    = {G{\"o}ttsche, Joachim and Hinsch, Andreas and Wittwer, Volker},
  title     = {Electrochromic and optical properties of mixed WO3-TiO2 thin films produced by sputtering and the sol-gel technique},
  series = {Optical materials technology for energy efficiency and solar energy conversion XI: chromogenics for smart windows : 19 and 21 May 1992, Toulouse-Lab{\`e}ge. (SPIE proceedings series. 1728)},
  booktitle = {Optical materials technology for energy efficiency and solar energy conversion XI: chromogenics for smart windows : 19 and 21 May 1992, Toulouse-Lab{\`e}ge. (SPIE proceedings series. 1728)},
  editor    = {Hugo-Le Goff, Anne},
  publisher = {SPIE},
  address   = {Bellingham, Wash.},
  isbn      = {0-8194-0901-4},
  pages     = {13 -- 25},
  year      = {1992},
  language  = {en}
}
@article{GoettscheHinschWittwer1993,
  author    = {G{\"o}ttsche, Joachim and Hinsch, Andreas and Wittwer, Volker},
  title     = {Electrochromic mixed WO3-TiO2 thin films produced by sputtering and the sol-gel technique : a comparison / J. G{\"o}ttsche ; A. Hinsch ; V. Wittwer},
  series = {Solar Energy Materials and Solar Cells. 31 (1993), H. 3},
  journal   = {Solar Energy Materials and Solar Cells. 31 (1993), H. 3},
  isbn      = {0927-0248},
  pages     = {415 -- 428},
  year      = {1993},
  language  = {en}
}
@inproceedings{AchenbachBoschBreitbachetal.2013,
  author    = {Achenbach, Timm and Bosch, Timo and Breitbach, Gerd and G{\"o}ttsche, Joachim and Sauerborn, Markus},
  title     = {Theoretical and experimental investigations regarding open volumetric receivers of CRS},
  series = {Energy procedia : proceedings of the SolarPACES 2013 International Conference},
  volume    = {Vol. 49},
  booktitle = {Energy procedia : proceedings of the SolarPACES 2013 International Conference},
  issn      = {1876-6102},
  pages     = {1259 -- 1268},
  year      = {2013},
  language  = {en}
}
@article{SattlerRoegerSchwarzboezletal.2020,
  author    = {Sattler, Johannes Christoph and R{\"o}ger, Marc and Schwarzb{\"o}zl, Peter and Buck, Reiner and Macke, Ansgar and Raeder, Christian and G{\"o}ttsche, Joachim},
  title     = {Review of heliostat calibration and tracking control methods},
  series = {Solar Energy},
  volume    = {207},
  journal   = {Solar Energy},
  publisher = {Elsevier},
  address   = {Amsterdam},
  doi       = {10.1016/j.solener.2020.06.030},
  pages     = {110 -- 132},
  year      = {2020},
  abstract  = {Large scale central receiver systems typically deploy between thousands to more than a hundred thousand heliostats. During solar operation, each heliostat is aligned individually in such a way that the overall surface normal bisects the angle between the sun's position and the aim point coordinate on the receiver. Due to various tracking error sources, achieving accurate alignment ≤1 mrad for all the heliostats with respect to the aim points on the receiver without a calibration system can be regarded as unrealistic. Therefore, a calibration system is necessary not only to improve the aiming accuracy for achieving desired flux distributions but also to reduce or eliminate spillage. An overview of current larger-scale central receiver systems (CRS), tracking error sources and the basic requirements of an ideal calibration system is presented. Leading up to the main topic, a description of general and specific terms on the topics heliostat calibration and tracking control clarifies the terminology used in this work. Various figures illustrate the signal flows along various typical components as well as the corresponding monitoring or measuring devices that indicate or measure along the signal (or effect) chain. The numerous calibration systems are described in detail and classified in groups. Two tables allow the juxtaposition of the calibration methods for a better comparison. In an assessment, the advantages and disadvantages of individual calibration methods are presented.},
  language  = {en}
}
@article{GoettscheHoffschmidtSchmitzetal.2009,
  author    = {G{\"o}ttsche, Joachim and Hoffschmidt, Bernhard and Schmitz, Stefan and Sauerborn, Markus},
  title     = {Solar Concentrating Systems Using Small Mirror Arrays / G{\"o}ttsche, Joachim ; Hoffschmidt, Bernhard ; Schmitz, Stefan ; Sauerborn, Markus ; Buck, Reiner ; Teufel, Edgar ; Badst{\"u}bner, Karin ; Ifland, David ; Rebholz, Christian},
  series = {Proceedings of the 2nd International Conference on Energy Sustainability - 2008 : : presented ... August 10 - 14, 2008, Jacksonville, Florida, USA / sponsored by Advanced Energy Systems Division, ASME; Solar Energy Division, ASME},
  journal   = {Proceedings of the 2nd International Conference on Energy Sustainability - 2008 : : presented ... August 10 - 14, 2008, Jacksonville, Florida, USA / sponsored by Advanced Energy Systems Division, ASME; Solar Energy Division, ASME},
  publisher = {ASME},
  address   = {New York, NY},
  isbn      = {9780791843208},
  pages     = {1 -- 5},
  year      = {2009},
  language  = {en}
}