@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}
}
@inproceedings{DuranParedesMottaghyHerrmannetal.2020,
  author    = {Duran Paredes, Ludwin and Mottaghy, Darius and Herrmann, Ulf and Groß, Rolf Fritz},
  title     = {Online ground temperature and soil moisture monitoring of a shallow geothermal system with non-conventional components},
  series = {EGU General Assembly 2020},
  booktitle = {EGU General Assembly 2020},
  year      = {2020},
  abstract  = {We present first results from a newly developed monitoring station for a closed loop geothermal heat pump test installation at our campus, consisting of helix coils and plate heat exchangers, as well as an ice-store system. There are more than 40 temperature sensors and several soil moisture content sensors distributed around the system, allowing a detailed monitoring under different operating conditions.In the view of the modern development of renewable energies along with the newly concepts known as Internet of Things and Industry 4.0 (high-tech strategy from the German government), we created a user-friendly web application, which will connect the things (sensors) with the open network (www). Besides other advantages, this allows a continuous remote monitoring of the data from the numerous sensors at an arbitrary sampling rate.Based on the recorded data, we will also present first results from numerical simulations, taking into account all relevant heat transport processes.The aim is to improve the understanding of these processes and their influence on the thermal behavior of shallow geothermal systems in the unsaturated zone. This will in turn facilitate the prediction of the performance of these systems and therefore yield an improvement in their dimensioning when designing a specific shallow geothermal installation.},
  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}
}
@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}
}
@inproceedings{DerschGeyerHerrmannetal.2002,
  author    = {Dersch, J{\"u}rgen and Geyer, Michael and Herrmann, Ulf and Jones, Scott A. and Kelly, Bruce and Kistner, Rainer and Ortmanns, Winfried and Pitz-Paal, Robert and Price, Henry},
  title     = {Solar Trough Integration Into Combined Cycle Systems},
  series = {Solar engineering 2002 : proceedings of the International Solar Energy Conference ; presented at the 2002 International Solar Energy Conference, a part of Solar 2002 - Sunrise on the Reliable Energy Economy, June 15 - 20, 2002, Reno, Nevada},
  booktitle = {Solar engineering 2002 : proceedings of the International Solar Energy Conference ; presented at the 2002 International Solar Energy Conference, a part of Solar 2002 - Sunrise on the Reliable Energy Economy, June 15 - 20, 2002, Reno, Nevada},
  editor    = {Pearson, J. Boise},
  publisher = {ASME},
  isbn      = {0-7918-1689-3},
  doi       = {doi:10.1115/SED2002-1072},
  pages     = {351 -- 359},
  year      = {2002},
  language  = {en}
}
@techreport{SchwarzerGoettscheJellinghaus2006,
  author    = {Schwarzer, Klemens and G{\"o}ttsche, Joachim and Jellinghaus, Sabine},
  title     = {Farblichtstudie : Beleuchtung mit gesteuertem Farblicht - Untersuchung und Optimierung von Systemen zur Farblichtsteuerung : Abschlussbericht M{\"a}rz 2006},
  pages     = {39 S.},
  year      = {2006},
  language  = {de}
}
@inproceedings{MahdiDerschSchmitzetal.2022,
  author    = {Mahdi, Zahra and Dersch, J{\"u}rgen and Schmitz, Pascal and Dieckmann, Simon and Chico Caminos, Ricardo Alexander 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{BaumannTeixeiraBouraGoettscheetal.2010,
  author    = {Baumann, T. and Teixeira Boura, Cristiano Jos{\´e} and G{\"o}ttsche, Joachim and Hoffschmidt, Bernhard and O'Connell, B. and Schmitz, S. and Zunft, S.},
  title     = {Air/Sand heat exchanger design and materials for solar thermal power plant applications},
  series = {SolarPACES 2010 : the CSP Conference: electricity, fuels and clean water from concentrated solar energy ; 21 to 24 September 2010, Perpignan, France},
  booktitle = {SolarPACES 2010 : the CSP Conference: electricity, fuels and clean water from concentrated solar energy ; 21 to 24 September 2010, Perpignan, France},
  publisher = {Soc. OSC},
  address   = {Saint Maur},
  pages     = {146 -- 147},
  year      = {2010},
  language  = {en}
}
@article{KronhardtAlexopoulosReisseletal.2014,
  author    = {Kronhardt, Valentina and Alexopoulos, Spiros and Reißel, Martin and Sattler, Johannes Christoph and Hoffschmidt, Bernhard and H{\"a}nel, Matthias and Doerbeck, Till},
  title     = {High-temperature thermal storage system for solar tower power plants with open-volumetric air receiver simulation and energy balancing of a discretized model},
  series = {Energy procedia},
  volume    = {49},
  journal   = {Energy procedia},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1876-6102 (E-Journal) ; 1876-6102 (Print)},
  doi       = {10.1016/j.egypro.2014.03.094},
  pages     = {870 -- 877},
  year      = {2014},
  abstract  = {This paper describes the modeling of a high-temperature storage system for an existing solar tower power plant with open volumetric receiver technology, which uses air as heat transfer medium (HTF). The storage system model has been developed in the simulation environment Matlab/Simulink®. The storage type under investigation is a packed bed thermal energy storage system which has the characteristics of a regenerator. Thermal energy can be stored and discharged as required via the HTF air. The air mass flow distribution is controlled by valves, and the mass flow by two blowers. The thermal storage operation strategy has a direct and significant impact on the energetic and economic efficiency of the solar tower power plants.},
  language  = {en}
}