TY - CHAP A1 - Sauerborn, Markus A1 - Klimek, J. A1 - Hoffschmidt, Bernhard A1 - Essen, H. A1 - Sieger, S. A1 - Biegel, G. A1 - Göttsche, Joachim A1 - Hilger, Patrick T1 - Eurosun 2012 : radar technology for heliostat posititon control T2 - Eurosun 2012 : Solar energy for a brighter future : conference proceedings : Rijeka, 18.-22.09.2012 Y1 - 2012 SP - ID 80 CY - Rijeka ER - TY - CHAP A1 - Göttsche, Joachim A1 - Schwarzer, Klemens A1 - Röther, Sascha A1 - Jellinghaus, Sabine A1 - Helten, G. A1 - Wittmann, R. T1 - Efficient daylighting, heating and shading with rooflight heliostats T2 - Renewables in a changing climate : from Nano to Urban Scale : CISBAT 2009 : 2-3 September 2009, EPFL, Lausanne, Switzerland : proceedings Y1 - 2009 SP - 243 EP - 246 PB - Ecole Polytechnique Fédérale de Lausanne CY - Lausanne ER - TY - JOUR A1 - Blanke, Tobias A1 - Hagenkamp, Markus A1 - Döring, Bernd A1 - Göttsche, Joachim A1 - Reger, Vitali A1 - Kuhnhenne, Markus T1 - Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates JF - Geothermal Energy N2 - 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 Hellström’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. Y1 - 2021 U6 - https://doi.org/10.1186/s40517-021-00201-3 SN - 2195-9706 N1 - Corresponding author: Tobias Blanke VL - 9 IS - Article number: 19 PB - Springer CY - Berlin ER - TY - CHAP A1 - Duran Paredes, Ludwin A1 - Mottaghy, Darius A1 - Herrmann, Ulf A1 - Groß, Rolf Fritz T1 - Online ground temperature and soil moisture monitoring of a shallow geothermal system with non-conventional components T2 - EGU General Assembly 2020 N2 - 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. Y1 - 2020 N1 - EGU General Assembly 2020, Online, 4–8 May 2020 ER - TY - CHAP A1 - Kronhardt, Valentina A1 - Alexopoulos, Spiros A1 - Reißel, Martin A1 - Latzke, Markus A1 - Rendon, C. A1 - Sattler, Johannes Christoph A1 - Herrmann, Ulf T1 - Simulation of operational management for the Solar Thermal Test and Demonstration Power Plant Jülich using optimized control strategies of the storage system T2 - Energy procedia Y1 - 2015 SN - 1876-6102 SP - 1 EP - 6 ER - TY - JOUR A1 - Göttsche, Joachim A1 - Schwarzer, Klemens A1 - Röther, S. A1 - Jellinghaus, Sabine T1 - Efficient daylighting, heating and shading with rooflight heliostats JF - Conference Internationale Energie Solaire et Batiment Y1 - 2009 SP - 243 EP - 248 PB - EPFL CY - Lausanne ER - TY - CHAP A1 - Dersch, Jürgen A1 - Geyer, Michael A1 - Herrmann, Ulf A1 - Jones, Scott A. A1 - Kelly, Bruce A1 - Kistner, Rainer A1 - Ortmanns, Winfried A1 - Pitz-Paal, Robert A1 - Price, Henry ED - Pearson, J. Boise T1 - Solar Trough Integration Into Combined Cycle Systems T2 - 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 Y1 - 2002 SN - 0-7918-1689-3 U6 - https://doi.org/doi:10.1115/SED2002-1072 SP - 351 EP - 359 PB - ASME ER - TY - RPRT A1 - Schwarzer, Klemens A1 - Göttsche, Joachim A1 - Jellinghaus, Sabine T1 - Farblichtstudie : Beleuchtung mit gesteuertem Farblicht - Untersuchung und Optimierung von Systemen zur Farblichtsteuerung : Abschlussbericht März 2006 Y1 - 2006 ER - TY - CHAP A1 - Mahdi, Zahra A1 - Dersch, Jürgen A1 - Schmitz, Pascal A1 - Dieckmann, Simon A1 - Chico Caminos, Ricardo Alexander A1 - Teixeira Boura, Cristiano José A1 - Herrmann, Ulf A1 - Schwager, Christian A1 - Schmitz, Mark A1 - Gielen, Hans A1 - Gedle, Yibekal A1 - Büscher, Rauno T1 - Technical assessment of Brayton cycle heat pumps for the integration in hybrid PV-CSP power plants T2 - SOLARPACES 2020 N2 - 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). KW - Solar thermal technologies KW - Hybrid energy system KW - Concentrated solar power KW - Power plants KW - Energy storage Y1 - 2022 SN - 978-0-7354-4195-8 U6 - https://doi.org/10.1063/5.0086269 SN - 1551-7616 (online) SN - 0094-243X (print) N1 - SOLARPACES 2020: 26th International Conference on Concentrating Solar Power and Chemical Energy Systems, 28 September–2 October 2020, Freiburg, Germany IS - 2445 / 1 PB - AIP conference proceedings / American Institute of Physics CY - Melville, NY ER - TY - CHAP A1 - Baumann, T. A1 - Teixeira Boura, Cristiano José A1 - Göttsche, Joachim A1 - Hoffschmidt, Bernhard A1 - O'Connell, B. A1 - Schmitz, S. A1 - Zunft, S. T1 - Air/Sand heat exchanger design and materials for solar thermal power plant applications T2 - SolarPACES 2010 : the CSP Conference: electricity, fuels and clean water from concentrated solar energy ; 21 to 24 September 2010, Perpignan, France Y1 - 2010 SP - 146 EP - 147 PB - Soc. OSC CY - Saint Maur ER -