@inproceedings{RiegerOetjenvandeParetal., author = {Rieger, Anna and Oetjen, Arne and van de Par, Steven and Rabl, Hans-Peter}, title = {Einfluss der Dissonanz auf die Wahrnehmung der Ger{\"a}uschqualit{\"a}t}, series = {Fortschritte der Akustik DAGA 2022: 48. Jahrestagung f{\"u}r Akustik, 21. - 24. M{\"a}rz 2022, Stuttgart und Online}, volume = {48}, booktitle = {Fortschritte der Akustik DAGA 2022: 48. Jahrestagung f{\"u}r Akustik, 21. - 24. M{\"a}rz 2022, Stuttgart und Online}, publisher = {Deutsche Gesellschaft f{\"u}r Akustik e.V.}, address = {Stuttgart}, language = {de} } @article{EmbergerAltmannGebhardetal., author = {Emberger, Peter and Altmann, Robert and Gebhard, J{\"u}rgen and Thuneke, Klaus and Winkler, Markus and T{\"o}pfer, Georg and Rabl, Hans-Peter and Remmele, Edgar}, title = {Combustion characteristics of pure rapeseed oil fuel after injection in a constant volume combustion chamber with a non-road mobile machinery engine solenoid injector}, series = {Fuel}, journal = {Fuel}, number = {320}, publisher = {Elsevier}, doi = {10.1016/j.fuel.2022.123979}, abstract = {Pure rapeseed oil fuel (R100) according to standard DIN 51605 is a greenhouse gas saving option for the mobility sector. With its high energy density close to diesel fuel, R100 is suitable to operate non-road mobile machinery with a high power demand and long operating time, where electric drives reach their limits. Advantages are indicated for its use in environmentally sensitive areas like agriculture since R100 is highly biodegradable and non-toxic. However, R100 is characterised by differing physical and chemical properties compared to diesel. The objective of the research is to investigate the differences in the ignition and combustion behaviour of R100 compared to diesel fuel (DF). For this purpose, a constant volume combustion chamber is used, which is equipped with a modern solenoid injector for engines of non-road mobile machinery. The researched injector shows a different hydraulic behaviour when using R100 compared to DF in that the injected fuel mass is lower with R100 than with DF. In combination with the 14 \% by mass lower calorific value, less energy output is determined with R100. When varying the injection pressure, the impact on the ignition delay and combustion behaviour is much higher for R100 than for DF. Specifically, an increase of the injection pressure supports mixture preparation and thus partially compensates the differing physical properties of R100. The results of ignition delay measurements and net heat release analysis are as follows: At low load conditions with low injection pressure as well as a low combustion chamber temperature and pressure, R100 ignites later and shows a further delayed combustion compared to diesel. The opposite is observed for medium and high load conditions, where R100 ignites faster and without delayed combustion in comparison to DF. Thus, an adjustment of the heat release of R100 at the same level as for DF is possible by modifying the injection strategy. The research shows that for an optimised combustion of R100 the injection settings must be adjusted for every operation point separately. The results indicate how the injection parameters should be adjusted for different load conditions to realise a high-quality engine calibration for R100.}, language = {en} } @inproceedings{Rill, author = {Rill, Georg}, title = {A Three-Dimensional and Nonlinear Virtual Test Car}, series = {ENOC 2022, book of abstracts, 10th European Nonlinear Dynamics Conference: July 17-22, 2022, Lyon, France}, booktitle = {ENOC 2022, book of abstracts, 10th European Nonlinear Dynamics Conference: July 17-22, 2022, Lyon, France}, address = {Lyon}, pages = {49 -- 58}, abstract = {Virtual testing procedures have become a standard in vehicle dynamics. The increasing complexity of driver assistance sys- tems demand for more and more virtual tests, which are supposed to produce reliable results even in the limit range. As a consequence, simplified vehicle models, like the classical bicycle model or 4-wheel vehicle models, have to be replaced by a fully three-dimensional and nonlinear vehicle model, which also encompasses the details of the suspension systems. This paper presents a passenger car model, where the chassis, the four knuckles, and the four wheels are described by rigid bodies, the suspension system is modeled by the generic design kinematics, and the TMeasy tire model provides the tire forces and torques in all driving situations.}, language = {en} } @inproceedings{ArrietaCastroRill, author = {Arrieta Castro, Abel and Rill, Georg}, title = {Kinematic Versus Elasto-Kinematic Model of a Twistbeam Suspension}, series = {Advances in Dynamics of Vehicles on Roads and Tracks II, proceedings of the 27th Symposium of the International Association of Vehicle System Dynamics (IAVSD 2021): August 17-19, 2021, Saint Petersburg, Russia}, booktitle = {Advances in Dynamics of Vehicles on Roads and Tracks II, proceedings of the 27th Symposium of the International Association of Vehicle System Dynamics (IAVSD 2021): August 17-19, 2021, Saint Petersburg, Russia}, editor = {Orlova, Anna and Cole, David}, publisher = {Springer Nature}, doi = {10.1007/978-3-031-07305-2_59}, pages = {505 -- 605}, abstract = {The Twistbeam axle suspension is a cheap and robust layout for rear axles at front wheel driven midsize cars. Appropriate models have to take the elastic deformation of the torsion beam into account. A Finite Element approach requires detailed informations of the material properties and the shape which are usually only available in the final production stage. This paper presents a lumped mass model which can easily be integrated into a multibody vehicle model and can be used in the early stage of development. An approximation by the design kinematics further reduces the complexity of the model and considers only the kinematic properties of the Twistbeam suspension. Simulations using a nonlinear and three-dimensional vehicle model with different maneuvers, such as steady-state cornering, step steer input, and driving straight ahead on random road, demonstrate the performance and, in particular, the difference of the presented Twistbeam suspension models.}, language = {en} } @inproceedings{WagnerAlAbadiBuchner, author = {Wagner, Marcus and Al-Abadi, Ali and Buchner, Stefan}, title = {A Numerical-Based Model to Determine the Resonance of the Steel Cores of Transformers}, series = {ARWtr 2022 proceedings : 2022 7th Advanced Research Workshop on Transformers (ARWtr), October (23)24-26, 2022, Baiona, Spain}, booktitle = {ARWtr 2022 proceedings : 2022 7th Advanced Research Workshop on Transformers (ARWtr), October (23)24-26, 2022, Baiona, Spain}, editor = {L{\´o}pez-Fern{\´a}ndez, Xose M.,}, publisher = {IEEE}, isbn = {978-84-09-45157-9}, doi = {https://doi.org/10.23919/ARWtr54586.2022.9959938}, pages = {36 -- 41}, abstract = {The laminated steel core of transformers is one of the main sources of the generated sound, as it is excited by different electromagnetic effects during its normal operation. If the core is excited in its eigenfrequencies, the sound generated by a transformer will increase significantly. Therefore, knowledge of the core's eigenmodes and -frequencies in an early design stage can decrease expenses by avoiding costly modifications that might be required to avoid the sound levels exceeding the specified values after the final factory acceptance test. The current study focuses on developing a core resonance model to determine the eigenmodes and -frequencies of a transformer core. The core's geometry was simplified to a connected-beam structure and a numerical-based approach was applied. The accuracy of the developed model was validated against finite element method (FEM), using ANSYS on a reference core model.}, language = {en} } @inproceedings{KoernerReindlMeieretal., author = {K{\"o}rner, Patrick and Reindl, Andrea and Meier, Hans and Niemetz, Michael}, title = {A Theoretical Comparison of Different Virtual Synchronous Generator Implementations on Inverters}, series = {2022 24th European Conference on Power Electronics and Applications (EPE'22 ECCE Europe): 05-09 September 2022, Hannover, Germany}, booktitle = {2022 24th European Conference on Power Electronics and Applications (EPE'22 ECCE Europe): 05-09 September 2022, Hannover, Germany}, publisher = {IEEE}, pages = {9}, abstract = {The goal to overcome the global climate crisis leads to a rising demand for the usage of Renewable Energy Sources (RES). Decentralized control strategies are needed to allow the integration of RES into the grid. The Virtual Synchronous Generator (VSG) is proposed as a method to add virtual inertia to the grid by emulating the rotating mass of a Synchronous Generator (SG) on the control algorithm of an inverter. This paper presents the VSG control structure as well as the mathematical description in a unified form. Due to the fact that classical droop control can be seen as a special form of the VSG, their correlation is highlighted by evaluating the steady state output characteristics of the inverter. Furthermore, a theoretical comparison between different VSG topologies, including the VISMA-Method 2 and the synchronverter, is given. In order to achieve better voltage stability, principles to add virtual impedance to the inverter's output are described.}, language = {en} } @inproceedings{LaloSailerMottoketal., author = {Lalo, Erjola and Sailer, Andreas and Mottok, J{\"u}rgen and Siemers, Christian}, title = {Overhead-Aware Schedule Synthesis for Logical Execution Time (LET) in Automotive Systems}, series = {2022 IEEE 35th International System-on-Chip Conference (SOCC): 05-08 September 2022, Belfast, United Kingdom}, booktitle = {2022 IEEE 35th International System-on-Chip Conference (SOCC): 05-08 September 2022, Belfast, United Kingdom}, publisher = {IEEE}, isbn = {978-1-6654-5985-3}, doi = {10.1109/SOCC56010.2022.9908103}, pages = {1 -- 6}, abstract = {The Logical Execution Time (LET) has recently been integrated in multi-core automotive systems to ensure timing and dataflow determinism. Although buffering mechanisms are introduced to incorporate LET semantics, they do not guarantee that tasks are executed within their LET frames. In fact, LET and buffering semantics are violated if scheduling is not designed to execute all tasks within their LET frames and in a specific order. In this paper, we describe a scheduling synthesis technique for Fixed-Priority Scheduling (FPS) to achieve resource-efficient execution of LET systems. The proposed approach considers LET semantics, scheduling overheads, and delays caused by operating system operations and provides the possibility to optimize the schedule with respect to aspects like scheduling overheads. Our performance and feasibility evaluation shows that the proposed algorithm provides results in a reasonable amount of time for models of complex industrial applications. Thus, the integration of the proposed algorithm into an automated process is of high benefit to accelerate the development of vehicle applications.}, language = {en} } @incollection{BauerGawlikSterneretal., author = {Bauer, Franz and Gawlik, Julia and Sterner, Michael and Hamacher, Thomas}, title = {{\"U}bergreifende Energiesystemmodellierung}, series = {Optionen f{\"u}r ein nachhaltiges Energiesystem mit Power-to-X-Technologien: Transformation - Anwendungen - Potentiale. 4. Roadmap des Kopernikus-Projektes P2X, Phase II}, booktitle = {Optionen f{\"u}r ein nachhaltiges Energiesystem mit Power-to-X-Technologien: Transformation - Anwendungen - Potentiale. 4. Roadmap des Kopernikus-Projektes P2X, Phase II}, editor = {Ausfelder, Florian and Du Tran, Dinh}, publisher = {DECHEMA Gesellschaft f{\"u}r Chemische Technik und Biotechnologie e.V.}, address = {Frankfurt a.M.}, isbn = {978-3-89746-238-0}, pages = {17 -- 35}, language = {de} } @inproceedings{WagnerLehrerFrankeetal., author = {Wagner, Marcus and Lehrer, Tobias and Franke, Markus and Al-Abadi, Ali and Gamil, Ahmed}, title = {A Tank Resonance Model for Power Transformers}, series = {ARWtr 2022 proceedings, 2022 7th Advanced Research Workshop on Transformers (ARWtr): October (23)24-26, 2022, Baiona, Spain}, booktitle = {ARWtr 2022 proceedings, 2022 7th Advanced Research Workshop on Transformers (ARWtr): October (23)24-26, 2022, Baiona, Spain}, publisher = {IEEE}, organization = {Institute of Electrical and Electronics Engineers (IEEE)}, doi = {10.23919/ARWtr54586.2022.9959917}, pages = {7 -- 12}, abstract = {During the factory acceptance test, the sound levels are measured. If the measured sound levels exceed pre-specified values, modifications on the transformer's active part and/or tank need to be conducted. Tank resonance, if occurs, at twice main power frequency and its higher harmonics is one of the main reasons of amplifying the generated sound levels. Therefore, it is preferable to know already in the design stage about the occurrence of the tank resonance and propose reliable tank solutions. The current study presents a newly developed model for calculating the mode shapes and its corresponding eigenfrequencies of the tank.}, language = {en} } @article{GamischHuberGadereretal., author = {Gamisch, Bernd and Huber, Lea and Gaderer, Matthias and Dawoud, Belal}, title = {On the Kinetic Mechanisms of the Reduction and Oxidation Reactions of Iron Oxide/Iron Pellets for a Hydrogen Storage Process}, series = {Energies}, volume = {15}, journal = {Energies}, number = {21}, publisher = {MDPI}, doi = {10.3390/en15218322}, abstract = {This work aims at investigating the kinetic mechanisms of the reduction/oxidation (redox) reactions of iron oxide/iron pellets under different operating conditions. The reaction principle is the basis of a thermochemical hydrogen storage system. To simulate the charging phase, a single pellet consisting of iron oxide (90\% Fe2O3, 10\% stabilising cement) is reduced with different hydrogen (H2) concentrations at temperatures between 600 and 800 °C. The discharge phase is initiated by the oxidation of the previously reduced pellet by water vapour (H2O) at different concentrations in the same temperature range. In both reactions, nitrogen (N2) is used as a carrier gas. The redox reactions have been experimentally measured in a thermogravimetric analyser (TGA) at a flow rate of 250 mL/min. An extensive literature review has been conducted on the existing reactions' kinetic mechanisms along with their applicability to describe the obtained results. It turned out that the measured kinetic results can be excellently described with the so-called shrinking core model. Using the geometrical contracting sphere reaction mechanism model, the concentration- and temperature-dependent reduction and oxidation rates can be reproduced with a maximum deviation of less than 5\%. In contrast to the reduction process, the temperature has a smaller effect on the oxidation reaction kinetics, which is attributed to 71\% less activation energy (Ea,Re=56.9 kJ/mol versus Ea,Ox=16.0 kJ/mol). The concentration of the reacting gas showed, however, an opposite trend: namely, to have an almost twofold impact on the oxidation reaction rate constant compared to the reduction rate constant.}, language = {en} } @inproceedings{RauchBruecklEngel, author = {Rauch, Johannes and Br{\"u}ckl, Oliver and Engel, Bernd}, title = {Analysis and optimization of the steady state voltage deviation demand for reactive power planning using installed reactive power sources}, series = {NEIS 2022; Conference on Sustainable Energy Supply and Energy Storage Systems, 26-27 September 2022, Hamburg}, booktitle = {NEIS 2022; Conference on Sustainable Energy Supply and Energy Storage Systems, 26-27 September 2022, Hamburg}, editor = {Schulz, Detlef}, publisher = {VDE-Verlag}, address = {Berlin}, isbn = {978-3-8007-5983-5}, issn = {2510-6902}, pages = {175 -- 182}, abstract = {The provision of reactive power is one option for maintaining the grid voltage, that is defined as an ancillary service in Germany. This paper presents an approach for determining deficient voltage deviation demands within an electrical grid for long term reactive power planning investigations. In contrast to previous approaches, which evaluate the Q-behavior of extended ward elements or grid assets, voltage deviations are analyzed bus-specifically. So further reactive power planning investigations are able to scale and optimize additional reactive power sources directly on planning voltage limits using load flow sensitivity techniques. The focus lies on the analysis of the steady state demand at base case conditions. Therefore, a grid planning process is conceptualized. An optimal power flow algorithm based on Differential Evolution is used for an optimal reactive power dispatch of installed reactive power sources, e. g. reactive power compensation systems or (renewable) energy sources to minimize the total voltage deviation according to voltage limits of Transmission System Operators planning principles. Methodological and processuals specifications as well as an application use case with an exemplary transmission system are presented in this paper.}, language = {en} } @inproceedings{SchweibererRauchBrueckl, author = {Schweiberer, Philipp and Rauch, Johannes and Br{\"u}ckl, Oliver}, title = {Long-term analysis of industrial reactive power potentials with consideration of plant-internal grid restrictions using the example of an industrial plant in a distribution grid}, series = {NEIS 2022; Conference on Sustainable Energy Supply and Energy Storage Systems, 26-27 September 2022, Hamburg}, booktitle = {NEIS 2022; Conference on Sustainable Energy Supply and Energy Storage Systems, 26-27 September 2022, Hamburg}, editor = {Schulz, Detlef}, publisher = {VDE-Verlag}, address = {Berlin}, isbn = {978-3-8007-5983-5}, issn = {2510-6902}, pages = {51 -- 56}, abstract = {Since conventional generation plants provide a considerable share of reactive power but are gradually being shut down due to energy transition, leading to power deficits at the transmission grid level, new concepts for the supply of reactive power must be developed. As one possibility for the latter, industrial plants in the distribution grid are considered suitable, as their reactive power potentials can contribute to voltage maintenance and thus to a grid- or system-serving behavior. In this paper, the determination of reactive power potentials provided by industrial compensation systems (ICS) is presented. An industrial plant in the medium voltage grid, with three installed ICSs, is investigated. The potentials are determined and described based on their time characteristics, which provide information about the occurrence and distribution of inductive and capacitive potentials. A grid simulation of the investigated industrial grid is used to analyze the effects of retrieving the reactive power potentials regarding equipment utilizations and voltage limits.}, language = {en} } @misc{WalterSchwanzerHagenetal., author = {Walter, Stefanie and Schwanzer, Peter and Hagen, Gunter and Rabl, Hans-Peter and Dietrich, Markus and Moos, Ralf}, title = {Combined Ash and Soot Monitoring in Gasoline Particulate Filters with a Radio-Frequency-Based Sensor}, series = {SAE World Congress Experience, April 5-7, 2022, Detroit, Michigan, USA}, journal = {SAE World Congress Experience, April 5-7, 2022, Detroit, Michigan, USA}, abstract = {In recent years, it turned out that primarily the number of ultrafine particles and not their mass is relevant in terms of harmful health effects. Therefore, exhaust emission standards are constantly being tightened with regard to the particulate number. To meet the emission limits, particulate filters have become necessary for gasoline engines. Similar to diesel applications, gasoline particulate filters (GPFs) can be monitored via differential pressure measurement or via a radio-frequency approach (RF-sensor). The latter is based on the influence of the soot conductivity on the electromagnetic field. To control the GPF, ash detection is of crucial importance besides the soot load monitoring. With the differential pressure system, this is only possible with high uncertainties due to the low pressure increase caused by ash. The RF-sensor, however, has already demonstrated its potential for ash detection in diesel applications. In order to verify the applicability of the system for GPFs, filters were loaded via a method for fast ash loading. Thereby, it was shown that by evaluating resonant modes - especially the resonant frequency - the ash loading can easily be measured as long as the filter is soot-unloaded. In contrast, soot loading can be determined independently from this by considering a frequency-averaged transmission signal between the antennas of the RF-sensor. Using a setup for radio-frequency material characterization, the dielectric parameters of the generated ash were also measured. In comparison with the properties of the synthetic soot PrintexU, ash showed significantly lower dielectric losses. Thus, the evaluation of the loss-dependent quality factor, which is only possible at low soot loadings, allows a precise conclusion whether the filter is completely soot-free. Furthermore, using synthetic soot loading, it could be shown that soot detection via the averaged transmission signal is not affected by ash. In summary, it could be shown that with the RF-sensor, ash and soot can be simultaneously detected.}, language = {en} } @phdthesis{Schwanzer, author = {Schwanzer, Peter}, title = {Experimentelle Untersuchungen zur On-Board {\"U}berwachung von Partikelfiltern f{\"u}r den Einsatz an direkteinspritzenden Benzinmotoren}, publisher = {Verlag Dr. Hut}, address = {M{\"u}nchen}, isbn = {978-3-8439-5101-2}, pages = {194}, abstract = {This thesis deals with the development of a methodology for an improved on-board diagnosis of particulate filters in vehicles with gasoline direct injection (GDI) technology with regard to future emission legislations. In order to comply with statutory particle number limits, particulate filters are used in the exhaust gas aftertreatment for GDI-engines. The currently applied method for diagnostic purposes, a differential pressure sensor, will not be suitable for future legislations. Therefore, an on-board strategy with real-time ability shall be developed. To achieve this, the application of novel sensor concepts has been investigated, namely electrostatic soot sensors (ePM sensor) and radio frequency antennas (RF sensor). Due to the results of the ePM-sensors, no methodology for an on-board diagnosis based on an ePM sensor concept was made. The RF sensor showed varying sensitivities for different soot and different quantities of volatile components in the filter element. The analysis of the oxidation processes showed that the regeneration of the filter element is detected by the RF sensor. Furthermore, the stored amount of ash could be captured. Due to these findings, a concept for an improved on-board diagnosis strategy by means of an RF sensor concept was developed. In the course of the work it turned out that a combined sensor concept consisting of a differential pressure sensor and a RF sensor is most suitable. In a validation process, this sensor concept showed sufficient results concerning the detection capability of soot and ash loads as well as of the degree of damage of particulate filters. Especially for small amounts of ash, this sensor concept showed specific advantage. Also, the determination of the current amount of soot in the filter element proved to be suitable. Regarding the detection of damages, the sensor concept convinces through a higher sensitivity.}, language = {de} } @phdthesis{Grauvogl, author = {Grauvogl, Dominik}, title = {Multiphysikalische Auslegung einer fremderregten Synchronmaschine mit magnetischer Asymmetrie f{\"u}r einen Hochvolt-Achsantrieb}, editor = {Gerling, Dieter}, publisher = {Shaker Verlag}, address = {D{\"u}ren}, isbn = {9783844085532}, pages = {260}, abstract = {In der vorliegenden Arbeit wird eine fremderregte Synchronmaschine als Achsantrieb f{\"u}r ein Elektrofahrzeug entwickelt. Als Grundlage hierf{\"u}r dient ein bereits vorhandener Stator einer permanenterregten Synchronmaschine. Durch die Wiederverwendung des Stators ist eine maschinentypunabh{\"a}ngige Baukastenerweiterung in Form eines magnetfreien Rotors gegeben, wodurch die {\"o}konomischen und {\"o}kologischen Nachteile der Permanentmagnete ausgeschlossen sind. Bei der Auslegung des Rotors wird von Beginn an ein multiphysikalischer Entwicklungsansatz gew{\"a}hlt, mit dem der praxistaugliche Einsatz f{\"u}r den modularen Baukasten sichergestellt ist. Dabei ist die elektromagnetische Auslegung iterativ auf die mechanische Blechpaketfestigkeit, das thermische Verhalten und die magnetischen Ger{\"a}usche abgestimmt. In Kombination mit den gesetzten Restriktionen ergibt sich ein neuartiges asymmetrisches Polschuhdesign mit dem es m{\"o}glich ist, das geforderte Drehmoment mit gen{\"u}gend kleiner Welligkeit ohne eine Rotorschr{\"a}gung zu erreichen. Die Simulationsergebnisse sind durch die Vermessung eines aufgebauten Prototyps validiert und best{\"a}tigt. Ein abschließender Simulationsvergleich mit der baugleichen permanenterregten Synchronmaschine zeigt, dass die fremderregte Synchronmaschine hinsichtlich Performance, Wirkungsgrad und Ger{\"a}uschverhalten eine konkurrenzf{\"a}hige Alternative dazu ist.}, language = {en} } @phdthesis{Weber, author = {Weber, Sebastian}, title = {Charakterisierung verschiedener Wassereinspritztechnologien f{\"u}r Ottomotoren}, doi = {10.25673/86462}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:ma9:1-1981185920-884176}, pages = {xvii, 151}, abstract = {Die Reduktion von Kraftstoffverbrauch und Schadstoffemission bei gleichzeitiger Verbesserung der Fahrleistung bei kleinerem Hubraum und reduzierter Zylinderzahl, die erh{\"o}hte Performance und die Kompatibilit{\"a}t mit elektrifizierten Komponenten beschreiben die aktuellen Ziele und Herausforderungen der modernen Ottomotorentwicklung. Um alle Herausforderungen zu erf{\"u}llen, muss ein st{\"o}chiometrischer Betrieb sichergestellt werden. Dabei kann es jedoch an der Volllast zur {\"U}berschreitung thermischer Grenzen im Abgaspfad kommen, weswegen die Abgastemperatur ohne Leistungsverluste abgesenkt werden muss. Die Wassereinspritzung kombiniert Downsizing, Leistungssteigerung und die Verbesserung der Schadstoffemissionen wirkungsvoll miteinander und k{\"o}nnte einen Beitrag zur Erreichung der Klimaziele leisten. Um ein optimales Systemlayout zu erarbeiten, sind prozessuale Betrachtungen oft nicht ausreichend. Vielmehr m{\"u}ssen die Ph{\"a}nomene im Brennraum beobachtet werden. Schwerpunktm{\"a}ßig sind dies die Einbringung des Wassers, der Wandkontakt, die Spray- und Wandfilmverdampfung und somit die Wirksamkeit der Abgastemperaturreduktion und die Verbesserung des indizierten Wirkungsgrads. In einem ersten Schritt werden die Thermodynamik bei Wassereinspritzung analysiert und verschiedene Einspritztechnologien miteinander verglichen. Fokussiert wird die Verbrennung, die Ver{\"a}nderung in den gasf{\"o}rmigen und festen Abgasbestandteilen und die mechanische Belastung der Aggregate durch die Verbesserung der Z{\"u}ndwinkel. Die Mischungseinspritzung {\"u}ber den zentralen Hochdruckinjektor vereint den geringsten Wasserverbrauch mit bestm{\"o}glicher Schwerpunktlage, starker Reduktion des Partikelausstoßes und akzeptabler Erh{\"o}hung der mechanischen Belastung und ist damit das favorisierte Konzept. Neben den prozessualen Betrachtungen werden mit einem optisch zug{\"a}nglichen Versuchstr{\"a}ger zwei laseroptische Messtechniken zur Visualisierung fl{\"u}ssigen Wassers und der spektralen Trennung zwischen Wasser und Kraftstoff entwickelt und validiert. Damit werden die verschiedenen Varianten optisch vermessen und die Sensitivit{\"a}t gegen{\"u}ber ver{\"a}nderten Betriebs- und Randbedingungen ermittelt. Die Sammlereinspritzung zeigt die gr{\"o}ßten Tropfen, gefolgt von der Saugrohr- und der Mischungseinspritzung. Auch hat diese den mit Abstand gr{\"o}ßten Wandkontakt und die geringste Verdampfungsrate, ist zus{\"a}tzlich anf{\"a}llig f{\"u}r zyklische Schwankungen. Die Saugrohreinspritzung kennzeichnen kleine Tropfen, ein konzentriertes Einstr{\"o}men durch den Ventilspalt, ein fl{\"a}chiger Wandfilm auf der Kolbenoberseite und die Verbesserung der Tropfenverdampfung durch Turbulenz und die Nutzung von Phasing. Favorit ist abermals die Mischungseinspritzung. Eine hohe Wandfilm- und unmittelbare Sprayverdampfung kennzeichnen das System, wobei eine Erh{\"o}hung des Einspritzdrucks die Verdampfungsrate signifikant verbessert. Außerdem ist die Einspritzdauer am geringsten und die Reproduzierbarkeit am gr{\"o}ßten, jedoch auch der applikative Aufwand. Am favorisierten System werden weitere Analysen durchgef{\"u}hrt, unter anderem zur Ver{\"a}nderung der Bauteiltemperaturen, der Vergleich mit einer Ethanoleinspritzung oder die vielversprechende Kombination in Form einer Wasser-Ethanol-Mischungseinspritzung. Auf Basis der experimentellen Erkenntnisse wird ein CFD-Verfahren vorgestellt, das die Wassereinspritzung abbildet und somit die Virtualisierung in der Produktentwicklung vorantreibt. Neben der methodischen Vorgehensweise wird das Verfahren validiert und am Einzylinder- und Vollmotorbetriebspunkt vorgestellt. Die auftretenden Unterschiede werden analysiert und ausgew{\"a}hlte Parameteranalysen durchgef{\"u}hrt. Mit den Simulationen kann nachvollzogen werden, wie das Wasser die Zylinderlaufbahn benetzt und mit dem Kolben interagiert. Zusammenfassend charakterisiert diese Arbeit die g{\"a}ngigen Wassereinspritzvarianten auf unterschiedlichen Ebenen, gibt Optimierungsempfehlungen f{\"u}r die bestm{\"o}gliche Medienverdampfung und empfiehlt die Mischungseinspritzung als Systemlayout.}, subject = {Kolbenkraftmaschine}, language = {de} } @phdthesis{Steininger, author = {Steininger, Peter}, title = {Experimentelle und numerische Untersuchungen an einem solarselektiven W{\"a}rmed{\"a}mmsystem}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:91-diss-20220614-1615021-1-1}, pages = {xv, 170}, abstract = {Zur Erreichung der von der Bundesregierung gesteckten Ziele, bis zum Jahr 2050 den Prim{\"a}renergiebedarf im Geb{\"a}udesektor und die Treibhausgasemissionen betr{\"a}chtlich zu reduzieren, kommt der nachhaltigen und zukunftsorientierten energetischen Sanierung von Fassaden an Bestandsgeb{\"a}uden besondere Bedeutung zu. F{\"u}r die Applikation an Außenw{\"a}nden steht eine Vielzahl an herk{\"o}mmlichen und neuartigen D{\"a}mmsystemen zur Verf{\"u}gung, die entweder eine signifikante Erh{\"o}hung des thermischen Widerstands der Geb{\"a}udeh{\"u}lle oder die Nutzung der Sonne als zus{\"a}tzliche Energiequelle erm{\"o}glichen. Um die vorteilhaften Eigenschaften der Erzielung winterlicher solarer Gewinne, des sommerlichen {\"U}berhitzungsschutzes und der hohen D{\"a}mmwirkung an sonnenlosen Tagen in einem D{\"a}mmsystem zu vereinen, unter Ber{\"u}cksichtigung {\"o}kologischer Aspekte, sind Entwicklungen im Bereich von innovativen Fassadensystemen notwendig. Das Ziel dieser Arbeit war die konstruktive Entwicklung sowie die experimentelle und numerische Untersuchung eines rein mineralischen solarselektiven W{\"a}rmed{\"a}mmsystems, das die oben genannten Zielsetzungen erf{\"u}llt. Zur Bewertung der Leistungsf{\"a}higkeit des entwickelten Systems wurden an einem Prototyp, in einem eigens konzipierten Differenzklimakammerpr{\"u}fstand, station{\"a}re und dynamische Untersuchungen zum winkelabh{\"a}ngigen Solarstrahlungs- und W{\"a}rmetransport durchgef{\"u}hrt und bauphysikalische Kenngr{\"o}ßen, die einen Vergleich mit g{\"a}ngigen D{\"a}mmsystemen erlauben, abgeleitet. Der experimentell ermittelte winkelabh{\"a}ngige Gesamtenergiedurchlassgrad, der als station{\"a}re Kenngr{\"o}ße zur Bewertung der Solarstrahlungsleitung herangezogen wird, zeigt ein Maximum im Auslegungspunkt f{\"u}r Wintermonate (19° Einstrahlwinkel) und kann f{\"u}r hohe Sonnenst{\"a}nde, zur Vermeidung von sommerlichen {\"U}berhitzungseffekten, signifikant reduziert werden. Dar{\"u}ber hinaus wurden die experimentellen Ergebnisse zur Validierung von station{\"a}ren und dynamischen multiphysikalischen Simulationsmodellen des solarselektiven W{\"a}rmed{\"a}mmsystems eingesetzt, welche ein tieferes Verst{\"a}ndnis des W{\"a}rme- und Strahlungstransports erm{\"o}glichen. Unter Verwendung der validierten Simulationsmodelle wurden, ausgehend vom Prototyp, die wesentlichen konstruktiven Einflussfaktoren auf die Solarleitung und die D{\"a}mmwirkung des Systems ermittelt und das Verbesserungspotential entsprechend quantifiziert. Zudem wurden in einer j{\"a}hrlichen simulativen Untersuchung, unter Verwendung realer Wetterdaten, mithilfe zweier verbesserter Varianten des solarselektiven W{\"a}rmed{\"a}mmsystems, die Heizenergieeinsparpotentiale in der Winter- und {\"U}bergangszeit gegen{\"u}ber einer herk{\"o}mmlich ged{\"a}mmten Wandkonstruktion nachgewiesen.}, language = {de} } @techreport{GerhardsWeberKlafkaetal., author = {Gerhards, Christoph and Weber, Urban and Klafka, Peter and Golla, Stefan and Hagedorn, Gregor and Baumann, Franz and Brendel, Heiko and Breyer, Christian and Clausen, Jens and Creutzig, Felix and Daub, Claus-Heinrich and Helgenberger, Sebastian and Hentschel, Karl-Martin and von Hirschhausen, Christian and Jordan, Ulrike and Kemfert, Claudia and Krause, Harald and Linow, Sven and Oei, Pao-Yu and Pehnt, Martin and Pfennig, Andreas and Pr{\"a}ger, Fabian and Quaschning, Volker and Schneider, Jens and Spindler, Uli and Stelzer, Volker and Sterner, Michael and Wagener-Lohse, Georg and Weinsziehr, Theresa}, title = {Klimavertr{\"a}gliche Energieversorgung f{\"u}r Deutschland - 16 Orientierungspunkte}, series = {Diskussionsbeitr{\"a}ge der Scinetists for Future ; 7}, journal = {Diskussionsbeitr{\"a}ge der Scinetists for Future ; 7}, doi = {10.5281/zenodo.4409334}, abstract = {Als fairer Beitrag Deutschlands zur Einhaltung der globalen 1,5-Grad-Grenze werden 16 Orientierungspunkte f{\"u}r eine klimavertr{\"a}gliche Energieversorgung vorgestellt. Es wird davon ausgegangen, dass hierf{\"u}r die deutschen energiebedingten CO2-Emissio­nen in etwa 15 Jahren weitgehend auf Null sinken m{\"u}ssen. Energieeinsparung hilft, den notwendigen Ausbau von regenerativen Erzeugungskapazit{\"a}ten zu verringern. Der Verkehrssektor kann ebenso wie die Bereiche Prozess- und Geb{\"a}udew{\"a}rme hier­zu wesentlich beitragen. Die Kernenergie ist mit großen Risiken belastet und kann nicht hinreichend schnell aufgebaut werden. Biomasse in Form von Energie­pflan­zen zu nutzen, ist ineffizient und steht im Konflikt mit anderen Arten der Land­nut­zung. Importe klimaneutral erzeugter Energietr{\"a}ger in sehr großem Umfang er­for­dern extrem große Investitionen im Ausland. Sie sind eine ungesicherte Option auf die Zukunft. Entscheidend ist daher der ausreichend schnelle Ausbau von Photovoltaik (PV) und Wind­kraft in Deutschland. Sch{\"a}tzungsweise kann der Elektrizit{\"a}tsbedarf im Jahr 2030 z.B. durch den Ausbau auf ca. 350 GW PV und ca. 150 GW Windkraft nahe­zu voll­st{\"a}ndig regenerativ gedeckt werden. Damit ließe sich eine zum großen Teil elek­tri­fizierte Mobilit{\"a}t und W{\"a}rmeversorgung betreiben und ein Teil des ben{\"o}­tig­ten "gr{\"u}­nen" Wasserstoffs in Deutschland bereitstellen. Hierf{\"u}r ist ein j{\"a}hr­licher Zu­bau von durchschnittlich ca. 30 GW PV und ca. 9 GW Windkraft n{\"o}tig. Dies ist ca. sechs- (PV) bzw. dreimal (Wind) so hoch wie bisher vorgesehen und verlangt eine ge­sell­schaft­liche Kraftanstrengung. Ein weiter verz{\"o}gerter Ausbau m{\"u}sste mit noch deut­lich gr{\"o}ßeren gesellschaftlichen Anstrengungen f{\"u}r drastische Energieeinspa­run­gen oder Importe erneuerbarer Energie ausgeglichen werden. Insgesamt k{\"o}nnte dies noch deutlich schwieriger zu realisieren sein, als ein ambitionierter Ausbau. Da der Auf­bau der Kapazit{\"a}ten mehrere Jahre erfordert, ist es m{\"o}glich nachzusteuern, z. B. wenn erkennbar wird, dass sich ein ausreichend großer globaler Markt f{\"u}r Importe ent­wi­ckelt. Bis dahin ist es aus Verantwortung gegen­{\"u}ber der Zukunft und im Sinne des Pariser Vertrages empfehlenswert, die hier genannten Ausbauziele zu verfol­gen. Gr{\"u}ner, also aus erneuerbaren Energien hergestellter Wasserstoff und daraus abge­lei­tete Syntheseprodukte sind f{\"u}r die Dekarbonisierung von Industrieprozessen, den Flug- und Schiffsverkehr sowie f{\"u}r die Absicherung der Energieversorgung bei Dun­kel­flauten n{\"o}tig. Ohne die genannten Ausbauziele f{\"u}r Wind und Solar noch drastisch weiter zu erh{\"o}hen, stehen diese Produkte f{\"u}r Straßenverkehr und W{\"a}rmeversor­gung jedoch nicht in ausreichenden Mengen zur Verf{\"u}gung. Techniken zum Aus­gleich zwischen Elektrizit{\"a}tsangebot und -nachfrage sind verf{\"u}gbar und sollten recht­zeitig auf- bzw. ausgebaut werden. Hierzu geh{\"o}ren: Stromaustausch mit den Nach­barl{\"a}ndern, Flexibilisierung des Verbrauchs und Energiespeicherung. F{\"u}r deren Inte­gration sowie den Ausbau der Netze sollten z{\"u}gig verbesserte rechtliche Rah­men­bedingungen geschaffen werden. Die Kosten eines klimavertr{\"a}glichen Energiesystems sind mittel- bis langfristig nicht h{\"o}­her als im derzeitigen System. Gleichzeitig entstehen Arbeitspl{\"a}tze und Export­chan­cen durch Aufbau, Betrieb und Wartung einer regenerativen Energieversorgung in Deutschland und die energetische Geb{\"a}udesanierung. Die politischen Rahmenbe­din­gungen entscheiden, ob eine klimavertr{\"a}gliche Energieversorgung Deutschlands ge­lingt.}, language = {de} } @article{UhlarHeyderKoenig, author = {Uhlar, Stefan and Heyder, Florian and Koenig, Thomas}, title = {Assessment of two physical tyre models in relation to their NVH performance up to 300 Hz}, series = {Vehicle system dynamics}, volume = {59}, journal = {Vehicle system dynamics}, number = {3}, publisher = {Taylor\&Francis}, doi = {10.1080/00423114.2019.1681475}, pages = {331 -- 351}, abstract = {The prediction of structure-borne noise using numerical methods has a crucial influence during the development process of modern passenger cars. In order to minimise the dynamic forces from the chassis transferred to the body structure, multibody simulation (MBS) can be used. The link between the road surface and the chassis is established by the tyre and its own structural dynamic characteristics. Therefore, it is substantial and the main goal of the present paper to investigate the Noise, Vibration and Harshness (NVH) performance of two commercial physical tyre models available and commonly used in the market. The intention is to point out what kind of results (up-to-date) a user of these structural dynamic tyre models, namely FTire and CDtire/3D, will get with a focus on NVH. The authors strictly follow the established process of how to obtain the fitted tyre property files, as any other user of FTire and CDTire currently does. This process includes a measurement campaign of the real tyre and a subsequent fitting of the tyre property file. The fitting in this case is provided by the tyre model developers themselves, namely cosin and Fraunhofer ITWM. The tyre models are then integrated into the MBS software MSC.Adams where their performance will be assessed based on measured wheel-hub forces in the time and frequency domain up to 300 Hz.}, language = {en} } @article{SovacoolCabezaPiselloetal., author = {Sovacool, Benjamin K. and Cabeza, Luisa F. and Pisello, Anna Laura and Colladon, Andrea Fronzetti and Larijani, Hatef Madani and Dawoud, Belal and Martiskainen, Mari}, title = {Decarbonizing household heating: Reviewing demographics, geography and low-carbon practices and preferences in five European countries}, series = {Renewable \& Sustainable Energy Reviews}, journal = {Renewable \& Sustainable Energy Reviews}, number = {139}, publisher = {Elsevier}, doi = {10.1016/j.rser.2020.110703}, pages = {1 -- 28}, abstract = {What commonalities are there in sustainable or unsustainable heating practices in five high-income, high-emitting western European countries? What preferences do a nationally representative sample of the public in these countries hold towards low-carbon options? It is imperative that climate policy researchers and practitioners grapple with the difficulty of decarbonizing heat, which remains the largest single end-use service worldwide and which accounts about half of total final energy consumption. Based on a comparative assessment of five representative national surveys in Germany (N = 2009), Italy (N = 2039), Spain (N = 2038), Sweden (N = 2023), and the United Kingdom (N = 2000), this study explores the demographics and geography of household heat decarbonisation in Europe. By analyzing our country level data as well as our combined sample of 10,109 respondents, it investigates how people conceive of the purposes of low-carbon heat, their preferences for particular forms of heat supply, and their (at times odd) practices of heat consumption and temperature settings. Grounded in its original data, the study organizes its findings inductively across the five themes of literacy (heating knowledge, awareness and control), sustainability (heating practices, dynamics and conflicts), temperature (heating satisfaction and preferences), desirability of change (low-carbon heating priorities, business models and trust), and culture (country and national variation). The study also explores intersections between these dimensions, using multivariate analysis, as well as how preferences differ according to varying types of actors as well as geography and space.}, language = {en} } @inproceedings{GoetzRauchBrueckl, author = {Goetz, Rebecca and Rauch, Johannes and Br{\"u}ckl, Oliver}, title = {Techno-economic analysis of reactive power sources}, series = {NEIS 2021, Conference on Sustainable Energy Supply and Energy Storage Systems: Hamburg, 13.-14. September 2021}, booktitle = {NEIS 2021, Conference on Sustainable Energy Supply and Energy Storage Systems: Hamburg, 13.-14. September 2021}, editor = {Schulz, Detlef}, publisher = {VDE-Verlag}, isbn = {978-3-8007-5651-3}, pages = {286 -- 291}, abstract = {This paper presents different options to provide reactive power in electricity grid systems. Since conventional power plants are being phased out and the reactive power demand tends to increase, alternative technologies are needed to cover it. reactive power sources are being defined and specified in this submission. A technical evaluation and an economic analysis of selected reactive power sources are carried out, based on interviews with manufacturers and operators. As well a multifactorial techno-economic comparison of the evaluated reactive power sources is presented. The technical analysis addresses reactive power control-ranges, stochastic parameters, lifespans, electrical losses and dynamics of re-active power sources. It states that power electronics allow faster setpoint changes than mechanical technologies can achieve, but at the same time this is associated with the highest electrical losses of the reactive power sources considered here. Considering the economic analysis, relative investment costs per reactive power of conventional compensation systems turn out to be the most cost-efficient. With regard to the multifactorial techno-economic comparison, it is im-portant not only to standardize on reactive power that can be provided, but also to include the additional system-relevant properties of technologies in the evaluation as well as the costs in operation.}, language = {en} } @inproceedings{KlitsmanBruecklEller, author = {Klitsman, Maksym and Br{\"u}ckl, Oliver and Eller, Johannes}, title = {Analysis and simulation of the population driving behaviour and charging processes at different charging station types with electric vehicles}, series = {NEIS 2021, Conference on Sustainable Energy Supply and Energy Storage Systems: 13-14. September 2021, Hamburg}, booktitle = {NEIS 2021, Conference on Sustainable Energy Supply and Energy Storage Systems: 13-14. September 2021, Hamburg}, editor = {Schulz, Detlef}, publisher = {VDE-Verlag}, isbn = {978-3-8007-5651-3}, pages = {254 -- 260}, abstract = {Electric vehicles are one of the important components of the energy transition, which is necessary for the CO2 emission reduction. In order to estimate the influence of electromobility on electric grids at present day and in the future, the generation of realistic charge profiles is necessary. The main objective of this study is the development of an algorithm, which generates realistic charge time series of electric vehicles. The very huge and detailed input surveys enable to define different population groups, representing specific driving behaviour. These groups are then composed and scaled up, according to the statistical population structure of a chosen town or city in Germany, and show typical driving behaviour of all inhabitants. The charge profiles are calculated for several charge station types, based on daily electric vehicle user mobility, day type and household type. In addition, charge process occurrence is evaluated through a model, involving charge infrastructure presence, attractiveness of corresponding charge station type and charge process necessity.}, language = {en} } @inproceedings{BruecklWildfeuerSchaechinger, author = {Br{\"u}ckl, Oliver and Wildfeuer, M. and Sch{\"a}chinger, J.}, title = {Systemdienstleistungen durch Biogasanlagen}, series = {Biogas in der Landwirtschaft - Stand und Perspektiven: 7. FNR/KTBL-Onlinetagung 29.-30.09.2021, Darmstadt}, booktitle = {Biogas in der Landwirtschaft - Stand und Perspektiven: 7. FNR/KTBL-Onlinetagung 29.-30.09.2021, Darmstadt}, address = {Darmstadt}, isbn = {978-3-945088-83-8}, pages = {92 -- 101}, subject = {Biogasanlage}, language = {de} } @misc{SternerHeberl, author = {Sterner, Michael and Heberl, Michael}, title = {The ORBIT-Project: Biological methanation in a trickle-bed reactor - key results and next steps}, series = {5th Nuremberg Workshop on Methanation and 2nd Generation, N{\"u}rnberg Friedrich-Alexander-Universit{\"a}t, 28.05.2021}, journal = {5th Nuremberg Workshop on Methanation and 2nd Generation, N{\"u}rnberg Friedrich-Alexander-Universit{\"a}t, 28.05.2021}, organization = {Friedrich-Alexander-Universit{\"a}t Erlangen-N{\"u}rnberg / Lehrstuhl f{\"u}r Energieverfahrenstechnik}, language = {en} } @misc{Sterner, author = {Sterner, Michael}, title = {Wie wird Deutschland klimaneutral? Neue L{\"o}sungen f{\"u}r erneuerbare Energieerzeugung}, series = {Jahreskonferenz der Stiftung Nagelschneider zur Erforschung, M{\"u}nchen, 19.11.2021}, journal = {Jahreskonferenz der Stiftung Nagelschneider zur Erforschung, M{\"u}nchen, 19.11.2021}, address = {M{\"u}nchen}, language = {de} } @misc{Sterner, author = {Sterner, Michael}, title = {Strom - W{\"a}rme - Verkehr - Industrie: das Zusammenspiel der Sektoren {\"u}ber Power-to-X}, series = {Deutscher Ingenieurtag 2021, D{\"u}sseldorf 20. Mai 2021}, journal = {Deutscher Ingenieurtag 2021, D{\"u}sseldorf 20. Mai 2021}, publisher = {VDI-Verlag}, language = {de} } @misc{Sterner, author = {Sterner, Michael}, title = {Power-to-X for Europes Energy Transformation - Booster H2Global}, series = {Hydrogen Online Workshop Conference (Mission Hydrogen), 25.03.2021}, journal = {Hydrogen Online Workshop Conference (Mission Hydrogen), 25.03.2021}, language = {en} } @misc{Sterner, author = {Sterner, Michael}, title = {Technologieausblick Solarstromspeicher}, series = {Innovationsforum Photovoltaik, 18. Oktober 2021, Linz}, journal = {Innovationsforum Photovoltaik, 18. Oktober 2021, Linz}, language = {de} } @misc{Sterner, author = {Sterner, Michael}, title = {Gas aus einer Gesamtenergieversorgungsperspektive - Warum wir Power-to-X f{\"u}r die Klimaneutralit{\"a}t brauchen}, series = {Kopernikus-Konferenz Projekt "Ensure" (Deutsche Umwelthilfe), 15. April 2021}, journal = {Kopernikus-Konferenz Projekt "Ensure" (Deutsche Umwelthilfe), 15. April 2021}, language = {de} } @misc{Sterner, author = {Sterner, Michael}, title = {Gr{\"u}ner Wasserstoff - wo wir ihn brauchen f{\"u}r die Klimaneutralit{\"a}t}, series = {Energiewendeforum Wasserstoff (Gr{\"u}ner Strom Label e. V.), Bonn, 21. September 2021}, journal = {Energiewendeforum Wasserstoff (Gr{\"u}ner Strom Label e. V.), Bonn, 21. September 2021}, language = {de} } @misc{Sterner, author = {Sterner, Michael}, title = {Die Grenzen des Wasserstoff-Hypes}, series = {1. Mitteldeutscher Wasserstoffkongress, 2. November 2021, Leuna CCE Kulturhaus}, journal = {1. Mitteldeutscher Wasserstoffkongress, 2. November 2021, Leuna CCE Kulturhaus}, language = {de} } @techreport{ThemaKaulSterneretal., author = {Thema, Martin and Kaul, Anja and Sterner, Michael and Heberl, Michael}, title = {Optimierung eines Rieselbett-Bioreaktors f{\"u}r die dynamische mikrobielle Biosynthese von Methan mit Archaeen-Mikroorganismen in Power-to-Gas-Anlagen}, doi = {10.2314/KXP:1815321555}, abstract = {Das {\"u}bergeordnete Ziel des Vorhabens war die Entwicklung neuer technologischer M{\"o}glichkeiten f{\"u}r den biologischen Methanisierungsprozess mit Archaeen1 in Power-to-Gas-Anwendungen. Im Gegensatz zur technisch ausgereiften chemisch-katalytischen Methanisierung sind hier noch Potenziale zur Optimierung verfahrenstechnischer und biologischer Prozesse f{\"u}r das Speicherkonzept Power-to-Gas [7] vorhanden. Dabei sollte zum einen ein Rieselbett-Bioreaktor optimiert, simuliert und f{\"u}r die Hochskalierung vorbereitet werden. Zum anderen sollte eine Kombination optimal geeigneter Mikroorganismen und Packungsmaterialien selektiert und deren Verhalten und Eignung im Reaktor analysiert werden. Das Verhalten des entwickelten Systems sollte zun{\"a}chst im Labor- und Technikumsmaßstab und anschließend im Feldtest an einer bestehenden Power-to-Gas-Anlage untersucht werden. Hauptziel w{\"a}hrend des Feldtests war die Produktion von einspeisef{\"a}higem Methan sowie dessen Einspeisung ins Gasnetz. Ein Hauptziel des Projektes war es, die Normung und Standardisierung notwendiger Systemparameter und Semantik zur Beschreibung und Einbindung biologischer Methanisierungseinheiten in Power-to-Gas-Anlagen voranzutreiben. Dies sollte zum einen die Vergleichbarkeit der wissenschaftlichen Erkenntnisse verbessern und zum anderen unterst{\"u}tzend bei der Kommerzialisierung der Technologie wirken. Aus dem Projekt heraus wurde so die neue Normungsreihe VDI 4635 Power-to-X beim Verein Deutscher Ingenieure angestoßen.}, language = {de} } @unpublished{KaulBoellmannThemaetal., author = {Kaul, Anja and B{\"o}llmann, Andrea and Thema, Martin and Kalb, Larissa and St{\"o}ckl, Richard and Huber, Harald and Sterner, Michael and Bellack, Annett}, title = {Identification of Robust Thermophilic Methanogenic Archaea and Packing Material for High Liquid Hold-Up at Low Volumetric Gas Flow Rates for Use in Trickle-Bed Reactors for Biological Methanation}, series = {SSRN Electronic Journal}, journal = {SSRN Electronic Journal}, doi = {10.2139/ssrn.3940878}, abstract = {he hydrogen gas-to-liquid mass transfer is the limiting factor in biological methanation. In a trickle-bed reactor, mass transfer can be increased by high flow velocities in the liquid phase, by adding a packing material with high liquid hold-up, or by choosing methanogenic archaea with a high methane productivity. This study analyzed various packings and methanogenic strains from a hydrodynamic and microbial perspective. By analyzing twelve pure cultures of thermophilic methanogens for their ability to produce high quality methane and to form biofilms on different packings, strains of Methanothermobacter were found to perform better than thus of the genus Methanothermococcus. Best methane production and adherence was observed on DuraTop®, Bioflow 9, and filter foam. DuraTop® and Bioflow 9 had also a high dynamic liquid hold-up, but the maximum hold-up was determined for expanded clay. The ideal combination for use in the ORBIT-trickle-bed reactor was identified as Methanothermobacter thermoautotrophicus IM5 and DuraTop®.}, language = {en} } @article{ThemaWeidlichKauletal., author = {Thema, Martin and Weidlich, Tobias and Kaul, Anja and B{\"o}llmann, Andrea and Huber, Harald and Bellack, Annett and Karl, J{\"u}rgen and Sterner, Michael}, title = {Optimized biological CO2-methanation with a pure culture of thermophilic methanogenic archaea in a trickle-bed reactor}, series = {Bioresource Technology}, journal = {Bioresource Technology}, number = {333}, publisher = {Elsevier}, doi = {10.1016/j.biortech.2021.125135}, abstract = {In this study, a fully automated process converting hydrogen and carbon dioxide to methane in a high temperature trickle-bed reactor was developed from lab scale to field test level. The reactor design and system performance was optimized to yield high methane content in the product gas for direct feed-in to the gas grid. The reaction was catalyzed by a pure culture of Methanothermobacter thermoautotrophicus IM5, which formed a biofilm on ceramic packing elements. During 600 h in continuous and semi-continuous operation in countercurrent flow, the 0.05 m3 reactor produced up to 95.3 \% of methane at a methane production rate of 0.35 mCH43mR-3h-1. Adding nitrogen as carrier gas during startup, foam control and dosing of ammonium and sodium sulfide as nitrogen and sulfur source were important factors for process automation.}, language = {en} } @inproceedings{JupkeReindlMeieretal., author = {Jupke, Michael and Reindl, Andrea and Meier, Hans and Niemetz, Michael}, title = {Bidirectional DC-DC Converter with Digital Droop Parameterization}, series = {26th 2021 International Conference on Applied Electronics (AE): 7-8 Sept. 2021 Pilsen, Czech Republic}, booktitle = {26th 2021 International Conference on Applied Electronics (AE): 7-8 Sept. 2021 Pilsen, Czech Republic}, editor = {Pinker, Jiř{\´i}}, publisher = {Institute of Electrical and Electronics Engineers}, isbn = {978-80-261-0972-3}, doi = {10.23919/AE51540.2021.9542920}, pages = {1 -- 6}, abstract = {The key for decentralized battery systems is a robust and communication-less control strategy for autonomous power sharing of parallel-connected DC-DC converters. Battery systems improve the reliability and quality of power supply in renewable energy systems and enable power supply for off-grid, mobile applications, including islanded grids, home storage, and electric vehicles. In many cases, components with different electrical properties require different voltage levels. An adaptation is consequently essential and is normally implemented in DC grids for the batteries via bidirectional DC-DC converters. The power flow in both directions can thus be ensured. To achieve a power distribution in parallel connected DC-DC converters, a droop control in the form of a virtual internal resistor can be used. This paper presents a novel approach of a DC-DC converter with a digitally parameterizable droop resistor, whose voltage regulation is based on an analog operational amplifier circuit to ensure low delays and robustness. The droop resistor is adjusted with a microcontroller, which offers the possibility to apply a higher-level control for load sharing via an interface. Mathematical correlations are used to clearly define the parameters of the control. Furthermore, the circuit was completely simulated and tested in the hardware setup. The shown results verify the functionality and indicate only minor deviations. Therefore, this circuit is important for future use in distributed battery systems.}, language = {en} } @article{MonkmanSindersbergerPremetal., author = {Monkman, Gareth J. and Sindersberger, Dirk and Prem, Nina and Diermeier, Andreas and Szecsey, Tamara}, title = {Dielectric behaviour of magnetic hybrid materials}, series = {Physical Sciences Reviews}, volume = {7}, journal = {Physical Sciences Reviews}, number = {10}, publisher = {de Gruyter}, doi = {10.1515/psr-2019-0121}, pages = {1169 -- 1185}, abstract = {The objectives of this work include the analysis of electrical and magnetic properties of magneto-elastic hybrid materials with the intention of developing new techniques for sensor and actuator applications. This includes the investigation of dielectric properties at both low and high frequencies. The behaviour of capacitors whose dielectrics comprise magnetic hybrid materials is well known. Such interfacial magnetocapacitance can be varied according to magnetic content, magnetic flux density and the relative permittivity of the polymer matrix together with other dielectric content. The basic function of trapping electrical charges in polymers (electrets) is also established technology. However, the combination of magnetoactive polymers and electrets has led to the first electromagnetic device capable of adhering to almost any material, whether magnetically susceptible or not. During the course of this research, in addition to dielectrics, electrically conductive polymers based on (PDMS) matrices were developed in order to vary the electrical properties of the material in a targeted manner. In order to ensure repeatable results, this demanded new fabrication techniques hitherto unavailable. The 3D printing of silicones is far from being a mature technology and much pioneering work was necessary before extending the usual 3 d.o.f. to include orientation about and diffusion of particles in these three axes, thus leading to the concept of 6D printing. In 6D printing, the application of a magnetic field can be used during the curing process to control the particulate distribution and thus the spatial filler particle density as desired. Most of the devices (sensors and actuators) produced by such methods contain levels of carbonyl iron powder (CIP) embedded magnetic filler of up to 70 wt\%. Contrary to this, a hitherto neglected research area, namely magnetoactive polymers (MAPs) having significantly lower magnetic particle concentrations (1 to 3 wt\% CIP) were also investigated. With filler concentrations lower than 3 wt\%, structures are formed which are completely absent at higher filler levels. CIP concentrations in the range of 1wt\% demonstrate the formation of toroidal structures. Further development of coherent rings with a compact order results as filler concentrations increase towards 2 wt\%. Above 3 wt\% the structure eventually disintegrates to the usual random order found in traditional MAP with higher CIP content. Structured samples containing 1\%-3 wt\% CIP were investigated with the aid of X-ray tomography where solitary ring structures can be observed and eventually the formation of capillary doubles. Over wavelengths ranging from 1 to 25 µm, spectroscopic analysis of thin film MAP samples containing 2 wt\% CIP revealed measurable magnetic-field-dependent changes in IR absorption at a wavenumber 2350 (λ = 4.255 µm). This was found to be due to the diamagnetic susceptibility of atmospheric carbon dioxide (CO2). Consequently, the first potential application for sparse matrix MAPs was found.}, language = {en} } @article{GamischGadererDawoud, author = {Gamisch, Bernd and Gaderer, Matthias and Dawoud, Belal}, title = {On the Development of Thermochemical Hydrogen Storage: An Experimental Study of the Kinetics of the Redox Reactions under Different Operating Conditions}, series = {Applied Sciences}, volume = {11}, journal = {Applied Sciences}, number = {4}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/app11041623}, pages = {1 -- 15}, abstract = {This work aims at investigating the reduction/oxidation (redox) reaction kinetics on iron oxide pellets under different operating conditions of thermochemical hydrogen storage. In order to reduce the iron oxide pellets (90\% Fe2O3, 10\% stabilizing cement), hydrogen (H2) is applied in different concentrations with nitrogen (N2), as a carrier gas, at temperatures between between 700 ∘C and 900 ∘C, thus simulating the charging phase. The discharge phase is triggered by the flow of a mixture out of steam (H2O) and N2 at different concentrations in the same temperature range, resulting in the oxidizing of the previously reduced pellets. All investigations were carried out in a thermo-gravimetric analyzer (TGA) with a flow rate of 250mL/min. To describe the obtained kinetic results, a simplified analytical model, based on the linear driving force model, was developed. The investigated iron oxide pellets showed a stable redox performance of 23.8\% weight reduction/gain, which corresponds to a volumetric storage density of 2.8kWh/(L bulk), also after the 29 performed redox cycles. Recalling that there is no H2 stored during the storage phase but iron, the introduced hydrogen storage technology is deemed very promising for applications in urban areas as day-night or seasonal storage for green hydrogen.}, language = {en} } @article{SteiningerGadererDawoud, author = {Steininger, Peter and Gaderer, Matthias and Dawoud, Belal}, title = {Assessment of the Annual Transmission Heat Loss Reduction of a Refurbished Existing Building with an Advanced Solar Selective Thermal Insulation System}, series = {Sustainability}, volume = {13}, journal = {Sustainability}, number = {13}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/su13137336}, pages = {1 -- 19}, abstract = {A numerical parameter sensitivity analysis of the design parameters of the recently published solar selective thermal insulation system (SATIS) has been carried out to enhance its thermal and optical properties. It turned out that the insulation properties of SATIS can be effectively improved by reducing the length of the glass closure element. Increasing the area share of the light conducting elements (LCEs) and decreasing their length-to-diameter (L/D) ratio were identified as key parameters in order to increase the solar gain. Two SATIS variants were compared with the same wall insulation without SATIS in a yearly energetic performance assessment. The SATIS variant with 10 mm length of the closure element, 44.2\% area share of LCE, as well as front and rear diameters of 12 mm/9 mm shows an 11.8\% lower transmission heat loss over the heating period than the wall insulation without SATIS. A new methodology was developed to enable the implementation of the computed solar gains of SATIS in 1D simulation tools. The result is a radiant heat flow map for integration as a heat source in 1D simulation models. A comparison between the 1D and 3D models of the inside wall heat fluxes showed an integral yearly agreement of 98\%.}, language = {en} } @inproceedings{ButtnerAlonsoVillaBohigasBoladerasetal., author = {Buttner, Johannes and Alonso-Villa, Cristina and Bohigas Boladeras, Pere and Kucera, Markus and Waas, Thomas}, title = {The Need for New Software Architectures for Next-generation Vehicle}, series = {Proceedings of the 5th International E-Conference on Advances in Engineering, Technology and Management (ICETM 2021)}, booktitle = {Proceedings of the 5th International E-Conference on Advances in Engineering, Technology and Management (ICETM 2021)}, isbn = {978-1-63248-192-4}, pages = {58 -- 61}, abstract = {Assuming that future connected cars with automated driving functions will require even more computing power and communication bandwidth, the current network infrastructure as well as the existing individualized control units are not a profitable option for such vehicles. In addition, changing user expectations demand flexible architectural patterns and upgradeability of software components without the need to visit the workshop. However, the current statically developed and configured ECU architecture does not offer any practicable possibilities for this. For these reasons, the research for a new dynamic and flexible architecture is necessary. This new type of system architecture is expected to meet future requirements in terms of space, cost, performance, energy efficiency and number of required computing units in the vehicle, which will arise as a result of the implementation/inclusion of new automated driving functionalities, and due to the changes in user expectations. Solutions to this issue can be found in the field of enterprise IT (cluster computing), in which technologies such as Ethernet, container-based virtualization and flexible software architectures have proven themselves to be very efficient for years. Relevant infrastructures, for example from cloud computing providers, have commonly been used in high-performance or high-availability applications. Thus, in the research project A 3F has been investigated which of these concepts and methods can be applied to modern vehicle system architectures. One of the main goals is to assess the synergy potential of the two sectors, information technology and automotive industry, which to date have very different orientations. However, this synergy is expected to grow strongly in the course of the developments mentioned above. In the following pages, the necessary changes related to hardware and software will be discussed briefly und will be compared to concepts and possible solutions from the IT world.}, language = {en} } @article{KurzweilScheuerpflug, author = {Kurzweil, Peter and Scheuerpflug, Wolfgang}, title = {State-of-charge monitoring and battery diagnosis of different lithium ion chemistries using impedance spectroscopy}, series = {Batteries}, volume = {7}, journal = {Batteries}, number = {1}, doi = {10.3390/batteries7010017}, pages = {16}, abstract = {For lithium iron phosphate batteries (LFP) in aerospace applications, impedance spectroscopy is applicable in the flat region of the voltage-charge curve. The frequency-dependent pseudocapacitance at 0.15 Hz is presented as useful state-of-charge (SOC) and state-of-health (SOH) indicator. For the same battery type, the prediction error of pseudocapacitance is better than 1\% for a quadratic calibration curve, and less than 36\% for a linear model. An approximately linear correlation between pseudocapacitance and Ah battery capacity is observed as long as overcharge and deep discharge are avoided. We verify the impedance method in comparison to the classical constant-current discharge measurements. In the case of five examined lithium-ion chemistries, the linear trend of impedance and SOC is lost if the slope of the discharge voltage curve versus SOC changes. With nickel manganese cobalt (NMC), high impedance modulus correlates with high SOC above 70\%.}, language = {en} } @article{SchmidtStraubSindersbergeretal., author = {Schmidt, Henrik and Straub, Benedikt B. and Sindersberger, Dirk and Br{\"o}ckel, Ulrich and Monkman, Gareth J. and Auernhammer, G{\"u}nter}, title = {Collision and separation of nickel particles embedded in a Poly dimethylsiloxan matrix under a rotating magnetic field: A strong magneto active function}, series = {Colloid and Polymer Science}, volume = {299}, journal = {Colloid and Polymer Science}, publisher = {Springer}, doi = {10.1007/s00396-020-04784-4}, pages = {955 -- 967}, abstract = {In order to function as soft actuators, depending on their field of use, magnetorheological elastomers (MREs) must fulfill certain criteria. To name just a few, these can include rapid response to external magnetic fields, mechanical durability, mechanical strength, and/or large deformation. Of particular interest are MREs which produce macroscopic deformation for small external magnetic field variations. This work demonstrates how this can be achieved by just a small change in magnetic field orientation. To achieve this, (super)paramagnetic nickel particles of size ≈ 160 μm were embedded in a non-magnetic polydimethylsiloxan (PDMS) (661-1301 Pa) and their displacement in a stepwise rotated magnetic field (170 mT) recorded using a video microscope. Changes in particle aggregation resulting from very small variations in magnetic field orientation led to the observation of a new strongly magneto-active effect. This configuration is characterized by an interparticle distance in relation to the angle difference between magnetic field and particle axis. This causes a strong matrix deformation which in turn demonstrates hysteresis on relaxation. It is shown that the occurrence strongly depends on the particle size, particle distance, and stiffness of the matrix. Choosing the correct parameter combination, the state can be suppressed and the particle-matrix system demonstrates no displacement or hysteresis. In addition, evidences of non-negligible higher order magnetization effects are experimentally ascertained which is qualitatively in agreement with similar, already theoretically described, particle systems. Even at larger particle geometries, the new strongly magneto-active configuration is preserved and could create macroscopic deformation changes.}, language = {en} } @article{RillBauerTopcagic, author = {Rill, Georg and Bauer, Florian and Topcagic, Edin}, title = {Performance of leaf spring suspended axles in model approaches of different complexities}, series = {Vehicle System Dynamics}, volume = {60}, journal = {Vehicle System Dynamics}, number = {8}, publisher = {Taylor\&Francis}, doi = {10.1080/00423114.2021.1928249}, pages = {2871 -- 2889}, abstract = {Axles with leaf spring suspension systems are still a popular choice in many commercial vehicles. However, leaf springs are not in perfect conformity to standard multibody vehicle models because they combine guidance and suspension in one single element. Combining standard multibody vehicle models with sophisticated finite element leaf spring models results in rather complex and computing time-consuming solutions. Purely kinematic models, defined by lookup tables or the design kinematics approach, cover only some but not all features of the leaf spring suspension. As shown here, the five-link model, which incorporates a quasi-static solution of the leaf spring compliance, provides a very practical model. It is comparatively lean and provides results of sufficient accuracy in the whole application range.}, language = {en} } @article{VerezBorriCrespoetal., author = {V{\´e}rez, David and Borri, Emiliano and Crespo, Alicia and Zsembinszki, Gabriel and Dawoud, Belal and Cabeza, Luisa F.}, title = {Experimental Study of a Small-Size Vacuum Insulated Water Tank for Building Applications}, series = {Sustainability}, volume = {13}, journal = {Sustainability}, number = {10}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/su13105329}, pages = {1 -- 11}, abstract = {Insulation of thermal energy storage tanks is fundamental to reduce heat losses and to achieve high energy storage efficiency. Although water tanks were extensively studied in the literature, the enhancement of the insulation quality is often overlooked. The use of vacuum insulation has the potential to significantly reduce heat losses without affecting the dimension of the storage system. This paper shows for the first time the results of the heat losses tests done for a 0.535 m3 water tank for residential building applications built with a double wall vacuum insulation. The different tests show that the rate of heat losses strictly depends on the temperature distribution inside the tank at the beginning of the experiment. Compared to a conventional water tank insulated with conventional materials, the U-value of the lateral surface was reduced by almost three times (from 1.05 W/K·m2 to 0.38 W/K·m2) using vacuum insulation. However, the bottom part, which is usually used to place the support parts and the piping, is the critical design part of those tanks acting as a thermal bridge with the ambient and enhancing heat losses.}, language = {en} } @inproceedings{ReindlMeierNiemetzetal., author = {Reindl, Andrea and Meier, Hans and Niemetz, Michael and Park, Sangyoung}, title = {Decentralized Battery Management System with Customized Hardware Components}, series = {IEEE 19th Student Conference on Research and Development (SCOReD), Sustainable Engineering and Technology towards Industry Revolution: 23-25 Nov. 2021, Kota Kinabalu, Malaysia}, booktitle = {IEEE 19th Student Conference on Research and Development (SCOReD), Sustainable Engineering and Technology towards Industry Revolution: 23-25 Nov. 2021, Kota Kinabalu, Malaysia}, publisher = {IEEE}, doi = {10.1109/SCOReD53546.2021.9652737}, pages = {350 -- 355}, abstract = {With an increasing number of sold electric vehicles (EVs), a large number of used batteries will be at disposal. How to deal with these resources is one of the major challenges in reducing the environmental impact of batteries throughout their entire life cycle. Heterogeneous cell parameters due to the different usage histories are a challenge for second-life use. The effort and cost of remanufacturing required to test and assemble a new battery pack is a further concern. Systems that combine battery packs/modules without full reassembly offer advantages such as cost and reusability. A decentralized battery management system (DBMS) provides a suitable architecture for such systems involving different types of batteries. In this paper, an architecture for a decentralized, battery state-dependent control is shown. The proposed DBMS supports various types of batteries, is scalable and flexibly adaptable for a wide range of applications. Despite the significant advantages, there are increased requirements to meet for the hardware implementation and the applied control strategies. Therefore, the necessary hardware components and their requirements are described and the hardware implementations are provided.}, language = {en} } @article{SchwanzerSchillingerMieslingeretal., author = {Schwanzer, Peter and Schillinger, Maximilian and Mieslinger, Johann and Walter, Stefanie and Hagen, Gunter and Maerkl, Susanne and Haft, Gerhard and Dietrich, Markus and Moos, Ralf and Gaderer, Matthias and Rabl, Hans-Peter}, title = {A Synthetic Ash-Loading Method for Gasoline Particulate Filters with Active Oil Injection}, series = {SAR International Journal of Engines}, volume = {14}, journal = {SAR International Journal of Engines}, number = {4}, publisher = {SAE International}, issn = {1946-3936}, doi = {10.4271/03-14-04-0029}, pages = {493 -- 506}, abstract = {To reduce particulate emissions, the use of particulate filters in diesel engines is meanwhile state of the art, while the integration of such systems in gasoline engines is now also necessary in order to comply with today's regulations. Over its lifetime, a gasoline particulate filter (GPF) collects ash components of fuel, lubrication oil, and materials originating from the catalytic coating and from engine abrasion. In the development and application process, synthetic ashing from GPFs is challenging. The ash of the lubrication oil can be increased in various ways, like oil-doped fuel, a separate oil burner, or changes in the piston-cylinder system of the engine. However, these methods show major disadvantages. For this reason, an improved approach is presented in this study, which allows a quick response to changes in combustion (e.g., engine knocking) and producing ash, which is more realistic due to its primary particle size and the density of ash plugs, in a shorter time. Therefore, an approach to accelerate ash loading by active oil injection using a multi-point injection (MPI) system is introduced. With the help of this methodology, an ashing capacity of 1.21 g/h is implemented, which is a high rate compared to other investigations. The primary particle size (evaluated by means of a transmission electron microscope), is in the same size range as those detected at the full-load curve during regular operation. A computer tomographic (CT) analysis of the incinerated particulate filter also shows that a very high density of ash plugs can be realized, which has also been found in the literature for real applications. In addition, with the help of a mass spectrometer (MS) and an intermediate weighing of the particulate filter, the current ash loading of the GPF could be determined with an accuracy of 1\%.}, language = {en} } @article{SchorrZentnerZimmermannetal., author = {Schorr, Philipp and Zentner, Lena and Zimmermann, Klaus and B{\"o}hm, Valter}, title = {Jumping locomotion system based on a multistable tensegrity structure}, series = {Mechanical systems and signal processing}, journal = {Mechanical systems and signal processing}, number = {152}, publisher = {Elsevier}, doi = {10.1016/j.ymssp.2020.107384}, abstract = {All known locomotion principles are limited respective to environmental conditions. Often, the occurrence of obstacles or gaps means the break-off for the operating motion systems. For such circumstances, a controllable jumping locomotion is required to cross these barriers. However, this locomotion demands sophisticated requirements to the actuation. The abrupt actuation is commonly realized by high dynamic actuators or complex mechanisms. In this work, a simple solution utilizing the multistability of a compliant tensegrity structure is described. Therefore, a two-dimensional tensegrity structure featuring four stable equilibria is considered. Based on bifurcation analyses a feasible actuation to control the current equilibrium configuration is derived. Changing between selected equilibrium states enables a great difference in potential energy, which yields a jumping motion of the structure. Based on numerical simulations a suitable actuation strategy is chosen to overcome obstacle and steps by jumping forward or backward, respectively. The theoretical approach is examined experimentally with a prototype of the multistable tensegrity structure. (c) 2020 Elsevier Ltd. All rights reserved. All known locomotion principles are limited respective to environmental conditions. Often, the occurrence of obstacles or gaps means the break-off for the operating motion systems. For such circumstances, a controllable jumping locomotion is required to cross these barriers. However, this locomotion demands sophisticated requirements to the actuation. The abrupt actuation is commonly realized by high dynamic actuators or complex mechanisms. In this work, a simple solution utilizing the multistability of a compliant tensegrity structure is described. Therefore, a two-dimensional tensegrity structure featuring four stable equilibria is considered. Based on bifurcation analyses a feasible actuation to control the current equilibrium configuration is derived. Changing between selected equilibrium states enables a great difference in potential energy, which yields a jumping motion of the structure. Based on numerical simulations a suitable actuation strategy is chosen to overcome obstacle and steps by jumping forward or backward, respectively. The theoretical approach is examined experimentally with a prototype of the multistable tensegrity structure.}, language = {en} } @inproceedings{ReindlSingerMeieretal., author = {Reindl, Andrea and Singer, Thomas and Meier, Hans and Niemetz, Michael and Park, Sangyoung}, title = {Framework to Test DC-DC Converters Developed for a Decentralized Battery Management System}, series = {2021 International Conference on Applied Electronics (AE): 7-8 Sept. 2021, Pilsen, Czech Republic}, booktitle = {2021 International Conference on Applied Electronics (AE): 7-8 Sept. 2021, Pilsen, Czech Republic}, publisher = {IEEE}, doi = {10.23919/AE51540.2021.9542882}, pages = {1 -- 6}, abstract = {DC- DC converters control the power flow and thus the power distribution between the components on different voltage levels. They are essential for (dis)charging batteries and influence the safety and stability of the entire battery management system (BMS). Therefore, testing the functionality and the reliability of DC-DC converters is crucial. This is especially true for decentralized battery management systems (DBMS), where multiple nodes communicate to collectively control the system. The used DC-DC converters are modified to parameterize them during operation via microcontroller interfaces. Integrating the communication into the control loop requires an analysis of the control behavior due to additional delays. Therefore, this paper proposes a framework to test DC-DC converters considering the control and communication perspectives. The response time, the control accuracy and stability of these DC-DC converters, e.g., under continuous and abrupt load changes, are measured in automated tests. The dedicated software framework simulates the DBMS and stimulates the hardware components (e.g. electronic loads, data acquisition) via respective interfaces (CAN, RS232). This allows the test of various DC-DC converters with flexibly adaptable load and power generation profiles. An initial application validates the test framework by verifying the aforementioned aspects and thus the applicability of a DC-DC converter within the DBMS.}, language = {en} } @article{PalombaNowakDawoudetal., author = {Palomba, Valeria and Nowak, Sebastian and Dawoud, Belal and Frazzica, Andrea}, title = {Dynamic modelling of Adsorption systems: a comprehensive calibrated dataset for heat pump and storage applications}, series = {Journal of energy storage}, volume = {33}, journal = {Journal of energy storage}, publisher = {Elsevier}, doi = {10.1016/j.est.2020.102148}, abstract = {The growing efforts for the development of clean and efficient energy systems require the use of a multi-disciplinary approach and the integration of multiple generation appliances. Among the fields that can be considered enabling technologies, adsorption systems for air conditioning and thermal energy storages, are constantly increasing their maturity. However, for a proper design and integration of such systems, there is the need for a simulation framework that is reliable and computationally convenient. In the present paper, the implementation of a dynamic model for adsorption systems is presented, which includes different components (adsorber, phase changer, sorption materials) and is structured as a library. Modelica language and the commercial software Dymola (R) are used for the analysis. Data for different heat exchangers and working pairs are calibrated using experimental results and the calibrated model is subsequently used for the design of an adsorber based on a plate heat exchanger for thermal energy storage applications. The results proved that the model is fast and can reproduce experimental results with good accuracy, thus being a useful tool for the design and optimization of the different components of sorption systems.}, language = {en} } @article{RillBauerKirchbeck, author = {Rill, Georg and Bauer, Florian and Kirchbeck, Mathias}, title = {VTT - a virtual test truck for modern simulation tasks}, series = {Vehicle system dynamics}, volume = {59}, journal = {Vehicle system dynamics}, number = {4}, publisher = {Taylor\&Francis}, doi = {10.1080/00423114.2019.1705356}, pages = {635 -- 656}, abstract = {The development of new technologies like advanced driver assistance systems or automated driving requires a flexible simulation environment of sufficient complexity. In general this flexibility is not provided by commercial software packages. This paper presents a three-dimensional and nonlinear hand-made model for heavy commercial vehicles including tractor and trailer as well as tractor and semitrailer combinations that can be used in different simulation environments, as well as in real-time applications. As typical for trucks, the torsional flexibility of the frame and a suspended driver's cabin are taken into account. The design kinematics makes it possible to handle different and quite complex axle suspensions very efficiently. Appropriate force elements are used to model various couplings between tractor and trailer or tractor and semitrailer, respectively. The virtual test truck environment (VTT) coded in ANSI C is extremely portable and can easily be embedded in commercial simulation packages like MATLAB/Simulink. It includes the TMeasy tyre model and offers flexible interfaces to third-party software tools.}, language = {en} } @inproceedings{SchubertLeeOoi, author = {Schubert, Martin J. W. and Lee, Wai-Kong and Ooi, Boon Yaik}, title = {Quantization and Sampling Effects in Fast Digitally Controlled Switch-Mode DC/DC Buck Converters}, series = {2021 IEEE Industrial Electronics and Applications Conference (IEACon): 22.11.2021 - 23.11.2021, Penang, Malaysia}, booktitle = {2021 IEEE Industrial Electronics and Applications Conference (IEACon): 22.11.2021 - 23.11.2021, Penang, Malaysia}, publisher = {IEEE}, isbn = {978-1-7281-9253-6}, doi = {10.1109/IEACon51066.2021.9654272}, pages = {56 -- 61}, abstract = {Software-defined control of DC/DC switch mode power converters features unequaled flexibility compared to analog control. For fast switching converters as recently used for low power applications, digital control may cause steady-state oscillations known as limit cycles. This effect based on a quantized duty cycle is compared to other aberrations such as output ripple voltage, which is inherent to any pulse-width modulator. A distinction is made between DC and AC errors. The latter are divided into synchronous and asynchronous output voltage disturbances. Synchronous AC errors are composed of the switching frequency and its harmonics.}, language = {en} }