TY - CHAP A1 - Weber, Karsten A1 - Haug, Sonja T1 - Automatisiertes Fahren: Evolutionäre Weiterentwicklung statt Disruption T2 - Vierte Jahreskonferenz des Netzwerks INDIGO zum Thema "Mobilität", 23.11.2018, , TH Deggendorf Y1 - 2018 ER - TY - JOUR A1 - Bringout, Gaël A1 - Erb, Wolfgang A1 - Frikel, Jürgen T1 - A new 3D model for Magnetic Particle Imaging using realistic magnetic field topologies for algebraic reconstruction JF - Inverse Problems N2 - We derive a new 3D model for magnetic particle imaging (MPI) that is able to incorporate realistic magnetic fields in the reconstruction process. In real MPI scanners, the generated magnetic fields have distortions that lead to deformed magnetic low-field volumes with the shapes of ellipsoids or bananas instead of ideal field-free points (FFP) or lines (FFL), respectively. Most of the common model-based reconstruction schemes in MPI use however the idealized assumption of an ideal FFP or FFL topology and, thus, generate artifacts in the reconstruction. Our model-based approach is able to deal with these distortions and can generally be applied to dynamic magnetic fields that are approximately parallel to their velocity field. We show how this new 3D model can be discretized and inverted algebraically in order to recover the magnetic particle concentration. To model and describe the magnetic fields, we use decompositions of the fields in spherical harmonics. We complement the description of the new model with several simulations and experiments, exploring the effects of magnetic fields distortion and reconstruction parameters on the reconstruction. Y1 - 2020 U6 - https://doi.org/10.1088/1361-6420/abb446 VL - 36 IS - 12 PB - IOP Publishing ER - TY - THES A1 - Rauch, Johannes T1 - Entwicklung eines Regelverfahrens für einen optimierten und zentralen Blindleistungsabruf zur Beeinflussung des Blindleistungshaushalts von Mittelspannungsnetzen unter Einhaltung von Netzrestriktionen N2 - Die Energiewende führt zu neuen Herausforderungen für Verteilungsnetzbetreiber hinsichtlich der Er-bringung von Systemdienstleistungen, der Integration weiterer Erzeugungsanlagen und Lasten sowie der Gewährleistung einer hohen Versorgungssicherheit und normgerechten Spannungsqualität. Die De-ckung der auftretenden Blindleistungsbedarfe seitens der Netzbetriebsmittel, Verbraucher und Erzeu-gungsanlagen gewinnt durch den Wegfall der Großkraftwerke für Netzbetreiber zunehmend an Bedeu-tung. Das Projekt SyNErgie beschäftigt sich diesbezüglich mit der Entwicklung neuartiger Blindleis-tungsmanagementsysteme für Mittelspannungsnetze. Ziel ist es, das bisher ungenutzte, freie Blindleis-tungspotential betrieblicher Kompensationsanlagen und dezentraler Erzeugungsanlagen (allgemein: Blindleistungsquellen) zu nutzen, um die Blindleistungsänderungsfähigkeit eines Verteilungsnetzes zu erhöhen. Diese Arbeit beschäftigt sich mit der Entwicklung eines zentralen Blindleistungsregelsystems, bei dem Blindleistungsquellen auf Basis von „Optimal Power Flow“-Berechnungen über eine zentrale Recheninstanz angesteuert werden. Zum Einsatz kommt dabei ein Optimierungsalgorithmus, der auf Basis des aktuellen Netzzustandes (Spannungs- und Auslastungsreserven) und des aktuellen Blindleis-tungspotentials der Blindleistungsquellen einen bedarfsoptimalen Abruf koordiniert. Das zentrale Re-gelverfahren wird in Netzmodellen verschiedenartiger Mittelspannungsnetzgruppen und unterschiedli-cher Art und Anzahl von Blindleistungsquellen angewendet sowie im Hinblick auf variierende Zielvor-gaben und Randbedingungen evaluiert und diskutiert. KW - Netzbetriebsführung KW - Blindleistungsmanagement KW - Optimierung Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-6595 ER - TY - THES A1 - Urban, Johannes T1 - Photoelektrisches Direktladen von Elektrofahrzeugen im Inselbetrieb N2 - Die Arbeit befasst sich mit der Ladung von Elektrofahrzeugen durch Solarenergie in einem Inselsystem. Diese Art der Ladung entlastet die Netze und hat einen sehr hohen Leistungswirkungsgrad. Es wurde ein Prototyp einer Direkt-ladestation gebaut, welche verschiedene Elektrofahrzeuge mit einem neuartigen Verfahren aufladen kann. Sie enthält einen optionalen Pufferakkumulator und einen Vollbrücken-Gegentaktwandler für die Ladung bei schlechter Solarleistung. Ein Teil der Arbeit behandelt ausführlich die Auslegung, die Komponenten und bisher undokumentiertes Verhalten von Gegentaktwandlern. Des Weiteren wird das Prinzip der Solardirekt-ladung und deren Umsetzung sowie die Umsetzung des Gesamtsystems beschrieben. Es folgt ein Kapitel zur Wirtschaftlichkeit der Solardirektladung mit Handlungsempfehlungen. Insgesamt lässt sich schließen, dass Solardirektladung bei nutzungsorientierter Auslegung der Anlage und langer Laufzeit wirtschaftlich ist. This work addresses the charging of electric vehicles with solar power in an off-grid system. Charging this way reduces the stress on the grid and has a very high power efficiency. A prototype of a direct charging station was built which is able to charge several different electric vehicles in a novel way. It includes an optional buffer battery and a full bridge converter for being able to charge electric vehicles at times o flow solar power. One chapter explains in detail the design, the components and so far undocumented properties of full and half bridge converters. The principle and the implementation of direct solar charging and the implementation of the whole system is described. The last chapter covers the cost effectiveness of solar chargin gas well as recommendations. All in all it can be stated that solar direct charging is ecomomically advantageous if it is projected according to the user’s demand. KW - Fotovoltaik KW - Stromtankstelle KW - Elektrofahrzeug KW - Pufferspeicher KW - Photovoltaik KW - Ladestation KW - Elektrofahrzeug KW - Pufferspeicher KW - Vollbrückenwandler Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-20285 ER - TY - JOUR A1 - Keim, Vincent A1 - Marx, P. A1 - Nonn, Aida A1 - Münstermann, Sebastian T1 - Fluid-structure-interaction modeling of dynamic fracture propagation in pipelines transporting natural gases and CO2-mixtures JF - International Journal of Pressure Vessels and Piping N2 - As part of current design standards, the Battelle Two-Curve Model (BTCM) is still widely used to predict and secure ductile crack arrest in gas transmission pipelines. For modern linepipe steels and rich natural gases or CO2 mixtures, the BTCM might lead to incorrect predictions. On the one hand, it suffers from the insufficient description of the individual physical processes in the pipe material and fluid itself. Furthermore, the model does not account for fluid-structure-interaction (FSI) effects during simultaneous running-ductile fracture (RDF) and mixture decompression. Numerical FSI models allow for a more sophisticated, coupled analysis of the driving forces for the failure of pipelines. This paper deals with the development of an FSI model for the coupled prediction of 3D pressure profiles acting on the inner pipe wall during crack propagation. The coupled Euler-Lagrange (CEL) method is used to link the fluid and structure models. In a Lagrange formulation, the modified Bai-Wierzbicki (MBW) model describes the plastic deformation and ductile fracture as a function of the underlying stress/strain conditions. The fluid behavior is calculated in a 3D model space by Euler equations and the GERG-2008 reference equation of state (EOS). The coupled CEL model is used to predict the RDF in small-diameter pipe sections for different fluid mixtures. The calculated 3D pressure distributions ahead and behind the running crack tip (CT) significantly differ in axial and circumferential directions depending on the mixture composition. The predicted FSI between the pipe wall and fluid decompression in 3D CEL/FSI model provides reliable knowledge about the pressure loading of the pipeline during RDF. KW - Fluid-Struktur-Wechselwirkung KW - Rissausbreitung KW - Pipeline KW - Gas KW - Pipeline failure KW - Fluid-structure-interaction KW - CO2 decompression KW - Running ductile fracture Y1 - 2019 U6 - https://doi.org/10.1016/j.ijpvp.2019.103934 VL - 175 IS - August PB - Elsevier ER - TY - CHAP A1 - Schorr, Philipp A1 - Böhm, Valter A1 - Zentner, Lena A1 - Zimmermann, Klaus T1 - Dynamical Investigation of Crawling Motion System based on a Multistable Tensegrity Structure T2 - Proceedings of the 15th International Conference on Informatics in Control, Automation and Robotics : Porto, Portugal, 29.07.2018 - 31.07.2018 N2 - The basic idea of this article is the utilization of the multistable character of a compliant tensegrity structure to control the direction of motion of a crawling motion system. A crawling motion system basing on a two-dimensional tensegrity structure with multiple stable equilibrium states is considered. This system is in contact with a horizontal plane due to gravity. For a selected harmonic actuation of the system small oscillations around the given equilibrium state of the tensegrity structure occur and the corresponding uniaxial motion of the system is evaluated. A change of the equilibrium state of the tensegrity structure yields to novel configuration of the entire system. Moreover, the motion behavior of the novel configuration is totally different although the actuation strategy is not varied. In particular, the direction of motion changes. Therefore, this approach enables a uniaxial bidirectional crawling motion with a controllable direction of motion using only one actuat or with a selected excitation frequency. Y1 - 2018 SN - 978-989-758-321-6 U6 - https://doi.org/10.5220/0006852701220130 SP - 122 EP - 130 PB - SCITEPRESS ER - TY - JOUR A1 - Schorr, Philipp A1 - Böhm, Valter A1 - Zentner, Lena A1 - Zimmermann, Klaus T1 - Motion characteristics of a vibration driven mobile tensegrity structure with multiple stable equilibrium states JF - Journal of Sound and Vibration N2 - A novel type of a vibration driven motion system based on a compliant tensegrity structure with multiple stable equilibrium states is considered. These equilibrium configurations correspond to different prestress states with different dynamical properties. Therefore, the motion characteristics can be varied by changing the equilibrium state. For the application in the fields of mobile robotics, these discrete adjustable dynamics are advantageous. The vibration modes of the structure as well as the corresponding motion characteristics of the system can be adapted to the given environmental conditions in order to ensure a reliable motion. In this paper, dynamical investigations of an exemplary two-dimensional multistable tensegrity structure are considered. For the chosen parameter values the structure features two relevant equilibrium configurations. The resulting motion system is in contact to a horizontal plane due to gravity and the actuation is realized by the harmonic variation of the length of a single tensioned member. The motion of the system is simulated for various actuation frequencies with the different equilibrium states as an initial configuration. A uniaxial or a planar movement occurs depending on the selection of the actuated member within the tensegrity structure. The steady state motion is evaluated regarding motion characteristics like the steady state velocity. Moreover, the influences on the motion behavior caused by the different equilibrium states as an initial condition are emphasized. (C) 2018 Elsevier Ltd. All rights reserved. KW - Compliant tensegrity structure KW - LOCOMOTION KW - Multistability KW - Vibration driven motion Y1 - 2018 U6 - https://doi.org/10.1016/j.jsv.2018.09.019 VL - 437 IS - December SP - 198 EP - 208 PB - Elsevier ER - TY - CHAP A1 - Böhm, Valter A1 - Schorr, Philipp A1 - Zimmermann, Klaus A1 - Zentner, Lena T1 - An Approach to the Estimation of the Actuation Parameters for Mobile Tensegrity Robots with Tilting Movement Sequences T2 - 2018 International Conference on Reconfigurable Mechanisms and Robots (ReMAR); 20-22 June 2018; Delft, Netherlands N2 - This paper deals with the locomotion by tilting sequences of shape-variable compliant tensegrity structures. The shape of these structures is controlled by manipulating their prestress state. The tensegrity structure is tilting as consequence of a suitable variation of its shape. By multiple repetition of such tilting sequences a motion is generated. Quasi-static considerations for the considered structures are presented in order to estimate the actuation parameters. For a proper number of actuators this quasi-static approach enables an analytical calculation of the actuation parameters of the structure in order to control the geometrical configuration as required. As an example a two-dimensional tensegrity structure which is in contact with a horizontal plane due to gravity is considered. By successive tilting sequences a uniaxial motion results. The excitation of the structure is calculated for a given change of shape with the quasi-static analysis. The according results are compared with transient dynamic simulations. Qualitative conclusions about the motion behavior and the usability of the quasi-static approach are given. KW - mobile robots KW - motion control KW - robot dynamics KW - structural engineering Y1 - 2018 U6 - https://doi.org/10.1109/REMAR.2018.8449871 SP - 1 EP - 8 PB - IEEE ER - TY - CHAP A1 - Carrillo Li, Enrique Roberto A1 - Schorr, Philipp A1 - Kaufhold, Tobias A1 - Rodríguez Hernández, Jorge Antonio A1 - Zentner, Lena A1 - Zimmermann, Klaus A1 - Böhm, Valter ED - Awrejcewicz, Jan ED - Kaźmierczak, Markek ED - Olejnik, Paweł T1 - Kinematic analysis of the rolling locomotion of mobile robots based on tensegrity structures with spatially curved compressed components T2 - Applicable Solutions in Non-Linear Dynamical Systems; 15th International Conference "Dynamical Systems - Theory and Applications" (DSTA 2019, 2-5 December, 2019, Lodz, Poland N2 - In this work, a tensegrity structure with spatially curved members is applied as rolling locomotion system. The actuation of the structure allows a variation of the originally cylindrical shape to a conical shape. Moreover, the structure is equipped with internal movable masses to control the position of the center of mass of the structure. To control the locomotion system a reliable actuation strategy is required. Therefore, the kinematics of the system considering the nonholonomic constraints are derived in this paper. Based on the resulting insight in the locomotion behavior a feasible actuation strategy is designed to control the trajectory of the system. To verify this approach kinematic analyses are evaluated numerically. The simulation data confirm the path following due to an appropriate shape change of the tensegrity structure. Thus, this system enables a two-dimensional rolling locomotion. The use of mechanically compliant tensegrity structures in mobile robots is an attractive research topic, due to the possibility to adjust their mechanical properties reversibly during locomotion. In this paper rolling locomotion of mobile robots based on simple tensegrity structures, consisting of three compressed spatially curved members connected to a continuous net of prestressed tensional members, is discussed. Planar locomotion of these robots is induced by the movement of internal masses. The movement direction can be changed by changing the robot's shape between a cylinder and a truncated cone. The paper focuses on the description of the kinematics of these systems with respect to the shape change. KW - Inverse kinematics KW - Nonholonomic mechanics KW - Tensegrity structure Y1 - 2019 UR - http://212.191.87.54:1616/k16/awrejcewicz/publikacje/T2.pdf SN - 978-83-66287-30-3 SP - 335 EP - 344 PB - Wydawnictwo Politechniki Łódzkiej CY - Łódź, Polen ER - TY - CHAP A1 - Nonn, Aida A1 - Paredes, Marcelo A1 - Keim, Vincent A1 - Wierzbicki, Tomasz T1 - Comparison of Fracture Models to Quantify the Effects of Material Plasticity on the Ductile Fracture Propagation in Pipelines T2 - Proceedings of the 2018 12th International Pipeline Conference, Volume 3: Operations, Monitoring, and Maintenance, Materials and Joining, September 24-28, 2018, Calgary, Alberta, Canada N2 - Various numerical approaches have been developed in the last years aimed to simulate the ductile fracture propagation in pipelines transporting CO2 or natural gas. However, a reliable quantification of the influence of material plasticity on the fracture resistance is still missing. Therefore, more accurate description of the material plasticity on the ductile fracture propagation is required based on a suitable numerical methodology. In this study, different plasticity and fracture models are compared regarding the ductile fracture propagation in X100 pipeline steel with the objective to quantify the influence of plasticity parameters on the fracture resistance. The plastic behavior of the investigated material is considered by the quadratic yield surface in conjunction with a non-associated quadratic plastic flow potential. The strain hardening can be appropriately described by the mixed Swift-Voce law. The simulations of ductile fracture are conducted by an uncoupled, modified Mohr-Coulomb (MMC) and the micromechanically based Gurson-Tvergaard-Needleman (GTN) models. In contract to the original GTN model, the MMC model is capable of describing ductile failure over wide range of stress states. Thus, ductile fracture resistance can be estimated for various load and fracture scenarios. Both models are used for the simulation of fracture propagation in DWTT and 3D pressurized pipe sections. The results from the present work can serve as a basis for establishing the correlation between plasticity parameters and ductile fracture propagation. Y1 - 2018 U6 - https://doi.org/10.1115/IPC2018-78366 ER - TY - JOUR A1 - Keim, Vincent A1 - Paredes, Marcelo A1 - Nonn, Aida A1 - Münstermann, Sebastian T1 - FSI-simulation of ductile fracture propagation and arrest in pipelines BT - Comparison with existing data of full-scale burst tests JF - International Journal of Pressure Vessels and Piping N2 - The fracture propagation and arrest control for pipelines transporting rich natural gases and high vapor pressure liquids is based on the Battelle Two-Curve Model (BTCM). Distinct limitations of this model were demonstrated for past and modern steels and gas mixtures. These can be related to the insufficient description of individual physical processes and interactions between the pipe material and transported mixture during the running ductile fracture. In the past, fluid-structure interaction (FSI) models enabled a more sophisticated, coupled analysis of the failure scenario. To quantify their capability of describing the multi-physical processes, the FSI models need to be verified by experimental data from full-scale burst tests (FSBT). Therefore, this paper deals with the simulation of five FSBTs from the literature on API grade X65 pipes with different pipe geometries, mixtures and initial conditions. The FSI is modeled by the coupled Euler-Lagrange (CEL) method. The modified Mohr-Coulomb (MMC) model is implemented in the CEL framework to describe the deformation and ductile fracture in the X65/L450 pipes. 3D Euler equations are used to calculate the mixture decompression with the GERG-2008 equation of state defining the volumetric behavior of a CO2-rich mixture, CH4 and H2. The extended model considers the effect of soil backfill on the pipe deformation and inertia. The numerical predictions agree well with the experimental findings in terms of the crack propagation speed and arrest length underlining the capability of the developed numerical tool. KW - Running ductile fracture KW - Crack arrest KW - Fluid-structure interaction KW - MMC model KW - CO2 decompression KW - Bruchmechanik KW - Fluid-Struktur-Wechselwirkung KW - Pipeline KW - Simulation Y1 - 2020 U6 - https://doi.org/10.1016/j.ijpvp.2020.104067 VL - 182 IS - May PB - Elsevier ER - TY - JOUR A1 - Keim, Vincent A1 - Nonn, Aida A1 - Münstermann, Sebastian T1 - Application of the modified Bai-Wierzbicki model for the prediction of ductile fracture in pipelines JF - International Journal of Pressure Vessels and Piping N2 - The complex mechanical and corrosive loads of modern pipeline systems transporting oil, natural gas and CO2 impose steadily increasing requirements on material properties. The majority of current design standards still limit the application of modern high toughness linepipe steels due to the simple specification of material requirements in terms of energy levels from Charpy impact or Battelle Drop-Weight-Tear (BDWT) tests. In consequence, research activities have been conducted recently aiming at developing modified or novel experimental methods for the characterization of the ductile fracture behavior. To quantify the effects of various parameters on fracture behavior and derive suitable correlations, it is necessary to accompany these activities by numerical simulations with appropriate ductile damage models. In this paper, the MBW model is applied to study the structural behavior of pipelines in ductile fracture regime. Due to its precise incorporation of the underlying load conditions, the damage model is successfully used to simulate the slant fracture behavior in Battelle Drop weight tear test specimens and pipe sections. In comparison to ductile damage models applied in former studies, namely the Gurson-Tvergaard-Needleman and Cohesive Zone model, the presented numerical methodology allows for a more detailed investigation of loading, material and geometry effects on fracture and crack arrest behavior of pipelines. KW - Running ductile fracture KW - Stress state conditions KW - MBW model KW - Pipeline failure KW - Slant fracture Y1 - 2019 U6 - https://doi.org/10.1016/j.ijpvp.2019.02.010 VL - 171 IS - March SP - 104 EP - 116 PB - Elsevier ER - TY - CHAP A1 - Steininger, Peter A1 - Gaderer, Matthias A1 - Dawoud, Belal T1 - Transient performance of a solar selective thermal insulation system T2 - 16th Advanced Building Skins Conference & Expo, 21 – 22/10/2021, Bern, Switzerland N2 - A prototype of a thermal insulation system to offer high selectivity of the solar gain regarding the solar incidence angle (SATIS) was applied to a typical solid brick masonry for existing buildings in Germany. Light conducting elements (LCEs) inclined at 19 ° were incorporated in SATIS, which equals the average solar noon angle in southern Germany during winter. The entire wall construction was experimentally investigated in a differential climatic chamber test bench at four different irradiation angles according to a dynamic test procedure. In addition, a conventional wall construction (CWC) has been measured. At SATIS’ design angle of 19 °, the SATIS wall construction shows a solar gain (SG) of 394.5 Wh/m², while the SG of the CWC amounts to only 25.4 Wh/m². The validated transient model of the SATIS wall construction showed that, at the end of the irradiation period of the dynamic test procedure (8 h), the solar heat penetrates to a depth of 253 mm and 111 mm inside the 385 mm thick brick wall masonry at the irradiation angles of 19 ° and 50 °, respectively. During the same time, the stored solar energy at 50 ° amounts to only 24.4 % of that stored at 19 °. Y1 - 2021 UR - https://www.researchgate.net/publication/355771950_Transient_performance_of_a_solar_selective_thermal_insulation_system PB - Advanced Buidling Skins GmbH ER - TY - JOUR A1 - Schächinger, J. A1 - Brückl, Oliver A1 - Becker, Mark A1 - Lechner, Raphael T1 - Results of the Research Project Optibiosy: Biogas plants as stabilizers of the power system? JF - BWK ENERGIE T2 - Biogasanlagen als Stabilisatoren des Stromsystems? Y1 - 2022 SN - 1436-4883 VL - 74 IS - 11-12 SP - 34 EP - 39 PB - VDI-Verlag CY - Düsseldorf ER - TY - RPRT A1 - Klitsman, Maksym A1 - Staudacher, Lars A1 - Brückl, Oliver A1 - Eller, Johannes A1 - Brey, Ludwig A1 - Eigenstetter, Florian T1 - neos - NetzEntwicklungsOffensive Strom - Schlussbericht BT - Projektlaufzeit: 01.09.2017 – 31.12.2021; gefördert durch Bayerisches Staatsministerium für Wirtschaft, Landesentwicklung und Energie N2 - Im Zuge der Energiewende werden die erneuerbaren Energien zur tragenden Säule unserer Stromversorgung. Bis 2025 sollen bundesweit 40-45 % des Stroms aus erneuerbaren Quellen stammen, bis 2050 sogar 80 %. Dabei wird der erzeugte Strom hauptsächlich aus Wind und Sonne stammen. Im Norden der Bundesrepublik wird Wind die Erzeugung dominieren, während im Süden, insbesondere in Bayern der Strom vornehmlich aus Photovoltaik gewonnen werden wird. Um die Ziele der Energiewende zu erreichen, wird neben den ausreichenden Erzeugungskapazitäten auch eine leistungsfähige Infrastruktur zur Verteilung und Nutzung des erneuerbaren Stroms notwendig sein. Planbarkeit und Sicherung der Versorgungsqualität bei zunehmenden Anteilen von volatiler Erzeugung werden dabei zu einer immer größeren Herausforderung. Das Projekt neos hat im engen Verbund mit den beteiligten Partnern wichtige tagesaktuelle Fragestellungen wissenschaftlich erörtert und untersucht, die sich durch die laufende Transformation des Energiesystems und den rasanten Ausbau der Anlagen zur erneuerbaren Energieerzeugung den Projektpartnern stellen. KW - Intelligentes Stromnetz KW - Energiewende KW - Netzplanung KW - Netzausbau KW - Elektromobilität KW - Spannungsqualität KW - regelbarer Ortsnetztransformator KW - Oberschwingungsbelastung KW - Netzberechnung KW - intelligente Netzbetriebsmittel Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-45248 ER - TY - CHAP A1 - Haumer, Anton A1 - Kral, Christian T1 - The New EDrives Library: A Modular Tool for Engineering of Electric Drives T2 - Proceedings of the 10th International Modelica Conference, March 10-12, 2014, Lund, Sweden N2 - Simulation is an indispensable tool for the engineering of systems containing electric drives. Depending on the design phase and the engineering task different levels of modeling details are required: proof of concept; investigation of energy and power consumption; design of control; etc. The new EDrives library provides three levels of abstraction for inverters: quasi static (neglecting electrical transients); averaging (neglecting switching effects) and switching – for serving different demands. The inverters can feed the machine models of the Modelica Standard Library: Modelica.Magnetic.FundamentalWave and the new Modelica.Magnetic.QuasiStatic.FundamentalWave. The EDrives library copes with arbitrary phase numbers and can be easily extended to develop new control algorithms. In this publication the structure of the library and the implemented control principles are presented. Furthermore; examples comparing the three different levels of abstraction are included. KW - control KW - Electric machines and drives KW - multi phase KW - power electronics KW - quasi static KW - switching KW - thermal behavior KW - transient Y1 - 2014 SN - 978-91-7519-380-9 U6 - https://doi.org/10.3384/ecp14096155 SN - 1650-3686 SN - 1650-3740 SP - 155 EP - 163 PB - Linköping University Electronic Press ER - TY - JOUR A1 - Gragger, Johannes V. A1 - Haumer, Anton A1 - Einhorn, Markus T1 - Averaged Model of a Buck Converter for Efficiency Analysis JF - Engineering Letters N2 - In this work a buck converter model for multidomain simulations is proposed and compared with a state-of-the-art buck converter model. In the proposed model no switching events are calculated. By avoiding the computation of the switching events in power electronic models the processing time of multidomain simulations can be decreased significantly. The proposed model calculates any operation point of the buck converter in continuous inductor current conduction mode (CICM) while considering the conduction losses and switching losses. It is possible to utilize the proposed modeling approach also for other dc-to-dc converter topologies. Laboratory test results for the validation of the proposed model are included. Y1 - 2010 UR - https://www.researchgate.net/profile/Markus-Einhorn/publication/41668038_Averaged_Model_of_a_Buck_Converter_for_Efficiency_Analysis/links/55100b490cf21287416cb105/Averaged-Model-of-a-Buck-Converter-for-Efficiency-Analysis.pdf VL - 18 CY - Hong Kong ER - TY - THES A1 - Heberl, Michael T1 - Power-to-Ammoniak BT - Möglichkeiten zur erneuerbaren Elektrifizierung und Dekarbonisierung der Ammoniakindustrie N2 - Ammoniak ist Grundbaustein für die Herstellung von Düngemitteln und dementsprechend für die Nahrungsmittelindustrie unentbehrlich. Ca. 40-50 % der Weltbevölkerung sind von Nahrungsmitteln abhängig, die mit Hilfe von Ammoniakdüngern hergestellten wurden. Weltweit wurden alleine im Jahr 2015 181 Mt Ammoniak produziert, wodurch die Ammoniakherstellung mit 1,2 % am gesamten Energieverbrauch der Welt beteiligt ist und für 0,93 % der globalen Treibhausgasemissionen zuständig ist. Auch in Zeiten der Energiewende ist diese Grundstoffchemikalie unentbehrlich, ist aber auf einem anderen Wege herzustellen. Ziel dieser Arbeit ist die Darstellung verschiedener Möglichkeiten zur erneuerbaren Elektrifizierung und Dekarbonisierung der Ammoniakindustrie, wodurch der Einsatz von herkömmlichen Energieträgern wie Erdgas, Kohle und Öl negiert werden kann. Ammoniak wird aktuell über das Haber-Bosch-Verfahren aus den Rohstoffen Erdgas, Kohle und Öl gewonnen. Bei diesem Verfahren wird über einen Primär- und Sekundärreformer Wasserstoff und Stickstoff gewonnen. Andere Gasbestandteile werden gefiltert oder umgewandelt, um schädliche Katalysatorgifte (CO, H2S) zu entfernen. Im Reaktor wird an Eisenkatalysatoren aus Wasserstoff und Stickstoff letztendlich Ammoniak hergestellt. Der Energieverbrauch des Haber-Bosch Verfahrens schwankt zwischen 7,8 MWh/t NH3 für eine moderne und sehr effiziente Anlage mit Erdgas und 13,6 MWh/t NH3 für eine alte mit Kohle betriebene Anlage. An Emissionen treten pro hergestellter Tonne Ammoniak je nach Rohstoff 1,6-3,8 t CO2-eq auf. Neben der Biomassevergasung gibt es mehrere rein elektrische Ansätze zur Ammoniakherstellung. Die unterschiedlichen elektrochemischen Ansätze zur direkten Ammoniaksynthese, wie der Einsatz von Flüssigsalzelektrolyten oder Feststoffelektrolyten, wurden in Abschnitt 3.2 vorgestellt. Einige dieser Technologien zeigen vielversprechende Ansätze, sind jedoch zum aktuellen Zeitpunkt noch zu weit von einem industriellen Einsatz entfernt. Der Einsatz der Wasserelektrolyse in Kombination mit einer Luftzerlegungseinheit ist die derzeit vielversprechendste Methode Ammoniak auf einem strombasierten und dekarbonisierten Wege herzustellen. Bei diesem System wird Wasserstoff im Elektrolyseur und Stickstoff in der Luftzerlegungseinheit hergestellt. Die Ammoniaksynthese findet hierbei in einem Reaktor nach Vorbild des Haber-Bosch-Prozesses statt. Mit diesem System ist ein Energieverbrauch von ca. 10 MWh/t NH3 notwendig. Durch den Einsatz von rein erneuerbar hergestelltem Strom als Energieträger lässt sich mit diesem Technologiezusammenschluss die Ammoniakherstellung komplett Emissionsfrei gestalten. Dadurch können alleine in Deutschland jährlich bis zu 7,8 Mt CO2-eq eingespart werden. Eine zukünftige Umstrukturierung der Ammoniakherstellung und der gesamten chemischen Industrie ist unabdingbar. Diese kann aber nur parallel mit einem Ausbau erneuerbarer Energien umgesetzt werden. Mit der Wasserelektrolyse und der Luftzerlegungseinheit sind die technischen Möglichkeiten für diesen Umbau bereits heute gegeben und brauchen nur noch eingesetzt werden. N2 - Ammonia is a fundamental raw material for the production of fertilizer and essential for the food industry. About 40-50 % of the world population depends on food produced with the assistance of ammonia fertilizers. In 2015 181 Mt ammonia was produced worldwide. The ammonia production is responsible for 1,2 % of the global energy consumption and 0,93 % of the global greenhouse gas emissions. Even in times of the energy transition this base chemical is essential, although it should be produced on a different way. It is therefore the objective of this work to show different possibilities for an electrified and decarbonised ammonia industry powered by renewable energies. As a result the use of conventional energy carriers like gas, coal and oil will be negotiated. Ammonia is produced with the Haber-Bosch process from gas, coal and oil as feedstock. In this process a primary and a secondary reformer is used to produce hydrogen and nitrogen. Other gaseous components are filtered and converted to remove catalyst poisons (CO, H2S). In the reactor iron catalysts are used to produce ammonia out of hydrogen and nitrogen. The energy consumption of the Haber-Bosch process varies between 7,8 MWh/t NH3 for a modern and really efficient gas based plant and 13,6 MWh/t NH3 for an old coal based plant. The production of one ton ammonia causes emissions between 1,6-3,8 t CO2-eq based on the used feedstock. Beside biomass gassing there are several electric technologies to produce ammonia. The different electrochemical technologies to synthesize ammonia on a direct way, like solid state electrolysis or molten salt electrolytes, are shown in section 3.2. Some of these technologies show a good potential, but all of them are far off the use in the industry. The use of an electrolyser in combination with an air separation unit is the most promising way to produce ammonia on an electrified and decarbonised way. In this system hydrogen is produced in the electrolyser and nitrogen in the air separation unit. The ammonia synthesis works in a reactor based on the Haber-Bosch process. Using this system the production of one ton ammonia has an energy consumption of 10 MWh. With the use of renewable energies in this combination of technologies a greenhouse gas emissions free ammonia production is possible. In Germany alone 7,8 t CO2-eq can be saved. A future reorganization of the ammonia industry and the complete chemical industry is indispensable. A parallel expand of renewable energies is necessary to realize this approach. With electrolysers and air separation units the technical possibilities for this reconstruction are already given. All that remains is the implementation of them. KW - Ammoniaksynthese KW - Haber-Bosch KW - Emissionen KW - Erneuerbare Energien Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-22167 ER - TY - JOUR A1 - Gärtner, Sebastian A1 - Marx-Schubach, Thomas A1 - Gaderer, Matthias A1 - Schmitz, Gerhard A1 - Sterner, Michael T1 - Techno-Economic Analysis of Carbon Dioxide Separation for an Innovative Energy Concept towards Low-Emission Glass Melting JF - energies N2 - The currently still high fossil energy demand is forcing the glass industry to search for innovative approaches for the reduction in CO2 emissions and the integration of renewable energy sources. In this paper, a novel power-to-methane concept is presented and discussed for this purpose. A special focus is on methods for the required CO2 capture from typical flue gases in the glass industry, which have hardly been explored to date. To close this research gap, process simulation models are developed to investigate post-combustion CO2 capture by absorption processes, followed by a techno-economic evaluation. Due to reduced flue gas volume, the designed CO2 capture plant is found to be much smaller (40 m3 absorber column volume) than absorption-based CO2 separation processes for power plants (12,560 m3 absorber column volume). As there are many options for waste heat utilization in the glass industry, the waste heat required for CO2 desorption can be generated in a particularly efficient and cost-effective way. The resulting CO2 separation costs range between 41 and 42 EUR/t CO2, depending on waste heat utilization for desorption. These costs are below the values of 50–65 EUR/t CO2 for comparable industrial applications. Despite these promising economic results, there are still some technical restrictions in terms of solvent degradation due to the high oxygen content in flue gas compositions. The results of this study point towards parametric studies for approaching these issues, such as the use of secondary and tertiary amines as solvents, or the optimization of operating conditions such as stripper pressure for further cost reductions potential. KW - economic evaluation KW - CO2-separation KW - glass industry KW - oxyfuel KW - methanation KW - power-to-gas Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-53627 N1 - Corresponding author: Sebastian Gärtner VL - 16 IS - 5 SP - 1 EP - 25 PB - MDPI CY - Basel ER - TY - JOUR A1 - Freni, Angelo A1 - Frazzica, Andrea A1 - Dawoud, Belal A1 - Chmielewski, Stefanie A1 - Calabrese, Luigi A1 - Bonaccorsi, Lucio Maria T1 - Adsorbent coatings for heat pumping applications: Verification of hydrothermal and mechanical stabilities JF - Applied Thermal Engineering N2 - This paper presents novel experimental methods for verification of both hydrothermal and mechanical stabilities of adsorbent coatings. Experiments have been carried out on zeolite-based coatings over aluminum substrates, prepared by a dip-coating technique developed at CNR-ITAE. Hydrothermal aging of several adsorbent coatings is ongoing. Adsorption and structural stability of some samples under test was successfully verified after 35000 aging cycles by isobars measurement and XRD analysis. Mechanical properties of coatings have been evaluated by applying different typologies of static and dynamic mechanical stresses. Results obtained have been compared with those achieved by subjecting adsorbent coatings prepared by Mitsubishi Plastic Incorporation (MPI) to the same characterization protocol. The comparison between the two types of coating returned that MPI coatings posses similar thermal stability and better mechanical strength than CNR-ITAE coatings. KW - Adsorbent coating KW - Adsorption heat pump KW - Hydrothermal stability KW - Mechanical stability Y1 - 2013 U6 - https://doi.org/10.1016/j.applthermaleng.2011.07.010 VL - 50 IS - 2 SP - 1658 EP - 1663 PB - Elsevier ER -