TY - CHAP A1 - Kelly, Bruce A1 - Herrmann, Ulf A1 - Hale, M.-J. T1 - Optimization Studies for Integrated Solar Combined Cycle Systems T2 - 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. Y1 - 2001 SN - 0-7918-1670-2 N1 - International Solar Energy Conference SP - 393 EP - 398 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Alexopoulos, Spiros A1 - Breitbach, Gerd A1 - Hoffschmidt, Bernhard T1 - Optimization of the channel form geometry of porous ReSiC ceramic membrane modules T2 - Proceedings / International Conference & Exhibition for Filtration and Separation Technology, FILTECH 2009 : October 13 - 15, 2009, Wiesbaden, Germany. Vol. 2 Y1 - 2009 SN - 978-3-941655-36-2 SP - 686 EP - 693 PB - Filtech Exhibitions Germany CY - Meerbusch ER - TY - JOUR A1 - Damm, Marc André A1 - Sauerborn, Markus A1 - Fend, Thomas A1 - Herrmann, Ulf T1 - Optimisation of a urea selective catalytic reduction system with a coated ceramic mixing element JF - Journal of ceramic science and technology Y1 - 2017 SN - 2190-9385 (Print) U6 - https://doi.org/10.4416/JCST2016-00056 SN - 2190-9385 (Online) VL - 8 IS - 1 SP - 19 EP - 24 PB - Göller CY - Baden-Baden ER - TY - CHAP A1 - Hoffschmidt, Bernhard A1 - Telle, R. A1 - Sauerborn, Markus A1 - Wagner, M. T1 - Optical measurement system for high temperature absorbers T2 - SolarPACES 2011 : concentrating solar power and chemical energy systems : 20 - 23 September, 2011, Granada, Spain Y1 - 2011 CY - Granada ER - TY - CHAP A1 - Mohan, Nijanthan A1 - Groß, Rolf Fritz A1 - Menzel, Karsten A1 - Theis, Fabian T1 - Opportunities and Challenges in the Implementation of Building Information Modeling for Prefabrication of Heating, Ventilation and Air Conditioning Systems in Small and Medium-Sized Contracting Companies in Germany – A Case Study T2 - WIT Transactions on The Built Environment, Vol. 205 N2 - Even though BIM (Building Information Modelling) is successfully implemented in most of the world, it is still in the early stages in Germany, since the stakeholders are sceptical of its reliability and efficiency. The purpose of this paper is to analyse the opportunities and obstacles to implementing BIM for prefabrication. Among all other advantages of BIM, prefabrication is chosen for this paper because it plays a vital role in creating an impact on the time and cost factors of a construction project. The project stakeholders and participants can explicitly observe the positive impact of prefabrication, which enables the breakthrough of the scepticism factor among the small-scale construction companies. The analysis consists of the development of a process workflow for implementing prefabrication in building construction followed by a practical approach, which was executed with two case studies. It was planned in such a way that, the first case study gives a first-hand experience for the workers at the site on the BIM model so that they can make much use of the created BIM model, which is a better representation compared to the traditional 2D plan. The main aim of the first case study is to create a belief in the implementation of BIM Models, which was succeeded by the execution of offshore prefabrication in the second case study. Based on the case studies, the time analysis was made and it is inferred that the implementation of BIM for prefabrication can reduce construction time, ensures minimal wastes, better accuracy, less problem-solving at the construction site. It was observed that this process requires more planning time, better communication between different disciplines, which was the major obstacle for successful implementation. This paper was carried out from the perspective of small and medium-sized mechanical contracting companies for the private building sector in Germany. KW - building information modelling KW - HVAC KW - prefabrication KW - construction KW - small and medium scaled companies Y1 - 2021 U6 - https://doi.org/10.2495/BIM210101 SN - 1743-3509 N1 - 4th International Conference on Building Information Modelling (BIM) in Design, Construction and Operations, 1–3 September 2021. Santiago de Compostela, Spain SP - 117 EP - 126 PB - WIT Press CY - Southampton ER - TY - CHAP A1 - Sattler, Johannes, Christoph A1 - Caminos, Ricardo Alexander Chico A1 - Ürlings, Nicolas A1 - Dutta, Siddharth A1 - Ruiz, Victor A1 - Kalogirou, Soteris A1 - Ktistis, Panayiotis A1 - Agathokleous, Rafaela A1 - Jung, Christian A1 - Alexopoulos, Spiros A1 - Atti, Vikrama Nagababu A1 - Teixeira Boura, Cristiano José A1 - Herrmann, Ulf T1 - Operational experience and behaviour of a parabolic trough collector system with concrete thermal energy storage for process steam generation in Cyprus T2 - AIP Conference Proceedings N2 - As part of the transnational research project EDITOR, a parabolic trough collector system (PTC) with concrete thermal energy storage (C-TES) was installed and commissioned in Limassol, Cyprus. The system is located on the premises of the beverage manufacturer KEAN Soft Drinks Ltd. and its function is to supply process steam for the factory's pasteurisation process [1]. Depending on the factory's seasonally varying capacity for beverage production, the solar system delivers between 5 and 25 % of the total steam demand. In combination with the C-TES, the solar plant can supply process steam on demand before sunrise or after sunset. Furthermore, the C-TES compensates the PTC during the day in fluctuating weather conditions. The parabolic trough collector as well as the control and oil handling unit is designed and manufactured by Protarget AG, Germany. The C-TES is designed and produced by CADE Soluciones de Ingeniería, S.L., Spain. In the focus of this paper is the description of the operational experience with the PTC, C-TES and boiler during the commissioning and operation phase. Additionally, innovative optimisation measures are presented. Y1 - 2020 U6 - https://doi.org/10.1063/5.0029278 N1 - SOLARPACES 2019: International Conference on Concentrating Solar Power and Chemical Energy Systems, 1–4 October 2019, Daegu, South Korea IS - 2303 SP - 140004-1 EP - 140004-10 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 - Mahdi, Zahra A1 - Rendón, Carlos A1 - Schwager, Christian A1 - Teixeira Boura, Cristiano José A1 - Herrmann, Ulf T1 - Novel concept for indirect solar-heated methane reforming T2 - AIP Conference Proceedings Y1 - 2019 U6 - https://doi.org/10.1063/1.5117694 SN - 0094-243X VL - 2126 SP - 180014-1 EP - 180014-7 PB - AIP Publishing CY - Melville, NY 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 - JOUR A1 - Göttsche, Joachim A1 - Alexopoulos, Spiros A1 - Dümmler, Andreas A1 - Maddineni, S. K. T1 - Multi-Mirror Array Calculations With Optical Error N2 - 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. KW - solar process heat KW - concentrating collector KW - raytracing KW - point-focussing system Y1 - 2019 SP - 1 EP - 6 ER - TY - CHAP A1 - Schwarzer, Klemens A1 - Vieira, Maria Eugenia A1 - Müller, Christoph A1 - Lehmann, Harry A1 - Coutinho, Lecimara T1 - Modular solar thermal desalination system with flat plate collector T2 - RIO 3 - World Climate & Energy Event : proceedings of the international conference held in Rio de Janeiro, Brazil, 1 -5 december 2003 / chief-ed.: Stefan Krauter ... Y1 - 2003 SN - 85-902710-2-1 SP - 281 EP - 286 PB - Krauter CY - Rio de Janeiro ER - TY - CHAP A1 - Alexopoulos, Spiros A1 - Rau, Christoph A1 - Hoffschmidt, Bernhard A1 - Breitbach, Gerd A1 - Latzke, Markus T1 - Modelling and validation of a transient heat recovery steam generator of the solar tower power plant Juelich T2 - Eurosun 2012 : Solar energy for a brighter future : conference proceedings : Rijeka, 18.-22.09.2012 Y1 - 2012 SP - ID 97 CY - Rijeka ER - TY - CHAP A1 - Zahra, Mahdi A1 - Phani Srujan, Merige A1 - Caminos, Ricardo Alexander Chico A1 - Schmitz, Pascal A1 - Herrmann, Ulf A1 - Teixeira Boura, Cristiano José A1 - Schmitz, Mark A1 - Gielen, Hans A1 - Gedle, Yibekal A1 - Dersch, Jürgen T1 - Modeling the thermal behavior of solar salt in electrical resistance heaters for the application in PV-CSP hybrid power plants T2 - SOLARPACES 2020 N2 - Concentrated Solar Power (CSP) systems are able to store energy cost-effectively in their integrated thermal energy storage (TES). By intelligently combining Photovoltaics (PV) systems with CSP, a further cost reduction of solar power plants is expected, as well as an increase in dispatchability and flexibility of power generation. PV-powered Resistance Heaters (RH) can be deployed to raise the temperature of the molten salt hot storage from 385 °C up to 565 °C in a Parabolic Trough Collector (PTC) plant. To avoid freezing and decomposition of molten salt, the temperature distribution in the electrical resistance heater is investigated in the present study. For this purpose, a RH has been modeled and CFD simulations have been performed. The simulation results show that the hottest regions occur on the electric rod surface behind the last baffle. A technical optimization was performed by adjusting three parameters: Shell-baffle clearance, electric rod-baffle clearance and number of baffles. After the technical optimization was carried out, the temperature difference between the maximum temperature and the average outlet temperature of the salt is within the acceptable limits, thus critical salt decomposition has been avoided. Additionally, the CFD simulations results were analyzed and compared with results obtained with a one-dimensional model in Modelica. KW - Solar thermal technologies KW - Hybrid energy system KW - Concentrated solar power KW - Energy storage KW - Photovoltaics Y1 - 2022 SN - 978-0-7354-4195-8 U6 - https://doi.org/10.1063/5.0086268 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 - Rendon, Carlos A1 - Schwager, Christian A1 - Ghiasi, Mona A1 - Schmitz, Pascal A1 - Bohang, Fakhri A1 - Caminos, Ricardo Alexander Chico A1 - Teixeira Boura, Cristiano José A1 - Herrmann, Ulf T1 - Modeling and upscaling of a pilot bayonettube reactor for indirect solar mixed methane reforming T2 - AIP Conference Proceedings N2 - A 16.77 kW thermal power bayonet-tube reactor for the mixed reforming of methane using solar energy has been designed and modeled. A test bench for the experimental tests has been installed at the Synlight facility in Juelich, Germany and has just been commissioned. This paper presents the solar-heated reactor design for a combined steam and dry reforming as well as a scaled-up process simulation of a solar reforming plant for methanol production. Solar power towers are capable of providing large amounts of heat to drive high-endothermic reactions, and their integration with thermochemical processes shows a promising future. In the designed bayonet-tube reactor, the conventional burner arrangement for the combustion of natural gas has been substituted by a continuous 930 °C hot air stream, provided by means of a solar heated air receiver, a ceramic thermal storage and an auxiliary firing system. Inside the solar-heated reactor, the heat is transferred by means of convective mechanism mainly; instead of radiation mechanism as typically prevailing in fossil-based industrial reforming processes. A scaled-up solar reforming plant of 50.5 MWth was designed and simulated in Dymola® and AspenPlus®. In comparison to a fossil-based industrial reforming process of the same thermal capacity, a solar reforming plant with thermal storage promises a reduction up to 57 % of annual natural gas consumption in regions with annual DNI-value of 2349 kWh/m2. The benchmark solar reforming plant contributes to a CO2 avoidance of approx. 79 kilotons per year. This facility can produce a nominal output of 734.4 t of synthesis gas and out of this 530 t of methanol a day. Y1 - 2020 U6 - https://doi.org/10.1063/5.0029974 N1 - SOLARPACES 2019: International Conference on Concentrating Solar Power and Chemical Energy Systems, 1–4 October 2019, Daegu, South Korea IS - 2303 SP - 170012-1 EP - 170012-9 ER - TY - CHAP A1 - Schwager, Christian A1 - Angele, Florian A1 - Schwarzbözl, Peter A1 - Teixeira Boura, Cristiano José A1 - Herrmann, Ulf T1 - Model predictive assistance for operational decision making in molten salt receiver systems T2 - SolarPACES: Solar Power & Chemical Energy Systems N2 - 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. KW - Power plants KW - Associated liquids KW - Decision theory KW - Electrochemistry Y1 - 2023 SN - 978-0-7354-4623-6 U6 - https://doi.org/10.1063/5.0151514 SN - 1551-7616 (online) SN - 0094-243X (print) N1 - SolarPACES: SOLAR POWER & CHEMICAL ENERGY SYSTEMS: 27th International Conference on Concentrating Solar Power and Chemical Energy Systems, 27 September–1 October 2021, Online IS - 2815 / 1 PB - AIP conference proceedings / American Institute of Physics CY - Melville, NY ER - TY - CHAP A1 - Schulze-Buxloh, Lina A1 - Groß, Rolf Fritz T1 - Miniature urban farming plant: a complex educational “Toy” for engineering students T2 - The Future of Education 11th Edition 2021 N2 - Urban farming is an innovative and sustainable way of food production and is becoming more and more important in smart city and quarter concepts. It also enables the production of certain foods in places where they usually dare not produced, such as production of fish or shrimps in large cities far away from the coast. Unfortunately, it is not always possible to show students such concepts and systems in real life as part of courses: visits of such industry plants are sometimes not possible because of distance or are permitted by the operator for hygienic reasons. In order to give the students the opportunity of getting into contact with such an urban farming system and its complex operation, an industrial urban farming plant was set up on a significantly smaller scale. Therefore, all needed technical components like water aeriation, biological and mechanical filtration or water circulation have been replaced either by aquarium components or by self-designed parts also using a 3D-printer. Students from different courses like mechanical engineering, smart building engineering, biology, electrical engineering, automation technology and civil engineering were involved in this project. This “miniature industrial plant” was also able to start operation and has now been running for two years successfully. Due to Corona pandemic, home office and remote online lectures, the automation of this miniature plant should be brought to a higher level in future for providing a good control over the system and water quality remotely. The aim of giving the student a chance to get to know the operation of an urban farming plant was very well achieved and the students had lots of fun in “playing” and learning with it in a realistic way. KW - urban farming KW - food production KW - smart engineering KW - 3D printing KW - sustainability Y1 - 2021 N1 - FOE 2021 : The Future of Education International Conference – Fully Virtual Edition; 01.07.2021-02.07.2021; Florence, Italy ER - TY - CHAP A1 - Beckmöller, S. A1 - Wolters, J. A1 - Breitbach, Gerd A1 - Penkalla, H. J. A1 - Schubert, F. T1 - Microstructural dependent constitutive equation for inelastic analysis of internally cooled IN 738 LC turbine blades T2 - Materials for advanced power engineering 1994 : proceedings of a conference held in Liege, Belgium, 3 - 6 Oct. 1994 Y1 - 1995 SN - 0792330749 SP - 829 EP - 839 PB - Kluwer CY - Dordrecht ER - TY - JOUR A1 - Vieira da Silva, Maria Eugenia A1 - Schwarzer, Klemens A1 - Hoffschmidt, Bernhard A1 - Pinheiro Rodrigues, Frederico A1 - Schwarzer, Tarik A1 - Costa Rocha, Paulo Alexandre T1 - Mass transfer correlation for evaporation–condensation thermal process in the range of 70 °C–95 °C JF - Renewable energy Y1 - 2013 SN - 1879-0682 (E-Journal); 0960-1481 (Print) VL - Vol. 53 SP - 174 EP - 179 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Göttsche, Joachim A1 - Hove, T. T1 - Mapping global, diffuse and beam solar radiation over Zimbabwe / T. Hove ; J. Göttsche JF - Renewable energy. 18 (1999), H. 4 Y1 - 1999 SN - 1879-0682 SP - 535 EP - 556 ER - TY - CHAP A1 - Anthrakidis, Anette A1 - Rusack, Markus A1 - Schwarzer, Klemens T1 - Low effort measurement method of PTC-efficiency 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 - 48 EP - 49 PB - Soc. OSC CY - Saint Maur ER -