@inproceedings{Haumer, author = {Haumer, Anton}, title = {Modeling and Control Design of an Educational Magnetic Levitation System}, series = {Proceedings of the 15th International Modelica Conference 2023, Aachen, October 9-11}, booktitle = {Proceedings of the 15th International Modelica Conference 2023, Aachen, October 9-11}, publisher = {Link{\"o}ping University Electronic Press}, issn = {1650-3686}, doi = {10.3384/ecp204763}, abstract = {A magnetic levitation system is a perfect educational example of a nonlinear unstable system. Only with suitable control, a small permanent magnet can be held floating stable below a coil. After modeling and simulation of the system, control of the system can be developed. At the end, the control algorithm can be coded on a microcontroller, connected to a pilot plant.}, language = {en} } @techreport{SoergelLudererEmelianovaetal., author = {S{\"o}rgel, Dominika and Luderer, Gunnar and Emelianova, Polina and Koch, Otto and Timpe, Christof and Bauer, Franz and Sterner, Michael}, title = {Kopernikus-Szenarienvergleich - Robuste Eigenschaften von Klimaschutzpfaden zur Treibhausgasneutralit{\"a}t 2045 und relevante Unsicherheiten}, publisher = {Kopernikus-Projekte}, address = {Potsdam}, pages = {54 S.}, abstract = {Im Rahmen der vier Kopernikus-Projekte - Ariadne, ENSURE, P2X und SynErgie - wird die Transformation des deutschen Energiesystems hin zur Klimaneutralit{\"a}t analysiert. Im vorliegenden Bericht werden hierbei robuste Kernaussagen und relevante Unsicherheiten derjenigen Szenarien der Kopernikus-Schwesterprojekte dargestellt, die zur Zielsetzung die Klimaneutralit{\"a}t 2045 haben. Hierbei liegt der Fokus auf Indikatoren, die eine besonders hohe klimapolitische Relevanz haben.}, language = {de} } @article{GamischEttengruberGadereretal., author = {Gamisch, Bernd and Ettengruber, Stefan and Gaderer, Matthias and Dawoud, Belal}, title = {Dynamic simulation of isothermal and non-isothermal reduction and oxidation reactions of iron oxide for a hydrogen storage process}, series = {Renewable and Sustainable Energy}, volume = {1}, journal = {Renewable and Sustainable Energy}, number = {1}, publisher = {ELSP, International Open Science Platform}, doi = {10.55092/rse20230004}, abstract = {This work aims first to develop a dynamic lumped model for the isothermal reactions of hydrogen/steam with a single iron oxide/iron pellet inside a tubular reactor and to validate the model results against the experimental reaction kinetic data with the help of our STA device. To describe the temporal change in mass, and consequently, the temporal heat of reaction, the shrinking core model, based on the geometrical contracting sphere, is applied. It turned out that, the simulation model can reproduce the experimental, temporal concentration and temperature-dependent conversion rates with a maximum deviation of 4.6\% during the oxidation reactions and 3.1\% during the reduction reactions. In addition, a measured isothermal storage process comprising one reduction and one oxidation phase with a holding phase in between on a single reacting pellet could be reproduced with a maximum absolute deviation in the conversion rate of 1.5\%. Moreover, a lumped, non-isothermal simulation model for a pelletized tubular redox-reactor including 2kg of iron oxide pellets has been established, in which the heat of reaction, heat transfer to the ambient and heat transfer between the solid and gas phases are considered. The temporal courses of the outlet gas concentration as well as the temperatures of the gas stream and the solid material at a constant input gas flow rate and a constant reacting gas inlet concentration but different input gas temperatures are estimated. Because of the endothermic nature of the reduction reaction, the inlet reacting gas temperature shall be kept high to prevent the severe temperature drop in the solid phase and, consequently, the significant reduction of the reaction rate. Contrary to that, the oxidation process requires lower input gas temperatures to avoid the excessive overheating of the reaction mass and, consequently, the sintering of the reacting pellets. Finally, five of the previous reactors have been connected in series to explore the influence of the changing inlet gas temperatures and concentrations on the dynamic performance of each storage mass.}, language = {en} } @unpublished{TakayasuWeiklDahmenetal., author = {Takayasu, Anna and Weikl, Simone and Dahmen, Victoria and Bogenberger, Klaus}, title = {Impact of Travel Stress and Infrastructure Quality on Cycling Mode Share: Insights From Multimodal Trajectory and Survey Data Analysis}, publisher = {Researchgate}, doi = {10.13140/RG.2.2.30696.85766}, abstract = {This study explores the relationship between travel stress, infrastructure quality, and cycling mode share. Utilizing multimodal trajectory data, survey responses on travel stress, and detailed road network information with geological and bicycle facility data, the study analyzes correlations between actual and perceived infrastructure quality, travel stress, and cycling mode share, as well as the impact of travel time and distance on cycling mode share. The results indicate significant correlations between perceived infrastructure quality and travel stress levels, and between travel stress levels and cycling mode share, particularly among regular bike users. However, clear correlations between actual and perceived infrastructure quality, and between perceived infrastructure quality and cycling mode share, were not observed. Additionally, direct effects of travel time and distance on cycling mode share were not evident. From these findings, three main insights emerge. Firstly, accurately estimating cycling mode share requires considering multiple parameters beyond travel time and distance. Secondly, to implement effective measures for bicycle facilities, a detailed analysis of perceived infrastructure quality, incorporating actual infrastructure design, is crucial. Lastly, travel stress, when carefully assessed with consideration of various factors beyond infrastructure design, emerges as a key determinant of travel mode choice. These insights have significant implications for future cycling research, including the development of travel mode choice models and estimating cycling demand. The study's valuable contributions advance efforts to promote cycling as a sustainable and preferred mode of transportation.}, language = {en} } @article{LiLange, author = {Li, Liwen and Lange, Klaus W.}, title = {Planning Principles for Integrating Community Empowerment into Zero-Net Carbon Transformation}, series = {smart cities}, volume = {2023}, journal = {smart cities}, number = {6}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/smartcities6010006}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-57765}, pages = {100 -- 122}, abstract = {The adoption of the UN 2030 Agenda and the Sustainable Development Goals is a landmark in international sustainability politics. For example, Europe has set ambitious targets to achieve 100 climate-neutral and smart cities by 2030. However, numerous case studies from different countries have found that accelerating the transition to net-zero carbon emissions is easily hampered by the lack of a coherent systems framework, and that implementation gaps remain at the community level. These barriers are often due to a lack of an adequate end-user (i.e., household) input and early planning participation. This work therefore aims to improve on conventional planning methods that do not reflect innovative technologies with uncertainty and may not be applicable due to the lack of community empowerment, which is a dynamic learning and intervention opportunity for end-users at different planning stages (i.e., outreach, survey, planning, implementation, management, and maintenance). Using the lessons learned from participatory action research, whereby the author was involved as a project director throughout the planning and design process, we identified a six-step cycle principle. The steps are (1) collective action commitments, (2) local values and resource identification, (3) carbon footprint inventory, (4) optimized integration of environment, economy, and energy action plans, (5) Flexible strategic energy system plans, and (6) digital performance monitoring. Ultimately, the outcomes provide application support for policymakers and planners and stimulate community engagement to contribute to the achievement of zero net carbon emissions.}, language = {en} } @article{MikhaeilNowakPalombaetal., author = {Mikhaeil, Makram and Nowak, Sebastian and Palomba, Valeria and Frazzica, Andrea and Gaderer, Matthias and Dawoud, Belal}, title = {Experimental and analytical investigation of applying an asymmetric plate heat exchanger as an evaporator in a thermally driven adsorption appliance}, series = {Applied Thermal Engineering}, journal = {Applied Thermal Engineering}, number = {228}, publisher = {Elsevier}, doi = {10.1016/j.applthermaleng.2023.120525}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-61115}, abstract = {This communication presents an experimental and analytical study on the evaporation mechanism in a closed-structured asymmetric plate heat exchanger (PHE) employed as a stagnant water evaporator for the application in an adsorption heat transformation appliance. To this aim, an experimental unit is constructed, which comprises two identical PHEs, one acting as an vaporator/condenser and the second, as an adsorber/desorber. Two endoscopes are mounted inside the investigated evaporator to visualize the evaporation mechanism when performing adsorption-evaporation processes under different boundary conditions. It turned out that the evaporation mechanism is a partially covered, thin film evaporation. A heat transfer analysis is performed to evaluate the heat transfer coefficient of the thin film evaporation () inside the investigated evaporator, resulting in -values between 1330 and 160 [W∙m-2∙K-1] over the investigated adsorption-evaporation time. Correlating the obtained () to the film thickness and the wetted area results in -values between 0.34 and 0.78 [mm] and wetted to total area ratios of 0.78 to 0.16. Besides, an analytical model has been developed and introduced to correlate the overall evaporator heat transfer coefficient with the adsorption potential and the time rate of change of the water uptake.}, language = {en} } @article{RauchBrueckl, author = {Rauch, Johannes and Br{\"u}ckl, Oliver}, title = {Achieving Optimal Reactive Power Compensation in Distribution Grids by Using Industrial Compensation Systems}, series = {Electricity}, volume = {4}, journal = {Electricity}, number = {1}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/electricity4010006}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-59139}, pages = {78 -- 95}, abstract = {This paper presents a method for integrating industrial consumers owning compensation systems as alternative reactive power sources into grid operating processes. In remuneration, they receive a market-based provision of reactive power. The aim is to analyze the potential of reactive power compensation systems of industrial companies connected to medium-voltage (10 kV-30 kV) AC grids in order to increase the reactive power ability of distribution grids. Measurement methods and reactive power potential results of six industrial companies are presented to characterize the amount and temporal availability of their reactive power potential. The presented approach for using the decentralized reactive power potential is a centralized reactive power control method and is based on optimal power flow (OPF) calculations. An optimization algorithm based on linear programming is used to coordinate a reactive power retrieval tuned to the actual demand. The influencing quantities are the current grid status (voltage and load flow capacity reserves at grid nodes and power lines) and the current reactive power potential of the reactive power sources. The compensation impact of six measured industrial companies on an exemplary medium-voltage grid is shown by an application example.}, language = {en} } @inproceedings{SchweibererRauchBrueckl, author = {Schweiberer, Philipp and Rauch, Johannes and Br{\"u}ckl, Oliver}, title = {Control strategy for industrial reactive power sources depending on a specified reactive power setpoint value}, series = {ETG Kongress 2023: Die Energiewende beschleunigen, 25.-26. Mai 2023, Kassel, Germany}, booktitle = {ETG Kongress 2023: Die Energiewende beschleunigen, 25.-26. Mai 2023, Kassel, Germany}, publisher = {VDE VERLAG}, address = {Berlin}, organization = {Energietechnische Gesellschaft }, isbn = {978-3-8007-6108-1}, pages = {553 -- 558}, abstract = {Industrial plants can provide reactive power (Q) for system- and grid-serving behavior, for which a functioning reactive power management system is essential. To make reactive power retrieval as efficient and safe as possible, the selection of reactive power sources to meet the Q-demand must consider their sensitivities and the restrictions of the industrial grid, such as operating equipment utilization or voltage limits. On this basis, a concept for a sensitivity-based control strategy that manages the reactive power retrieval of multiple reactive power sources depending on a predefined reactive power demand value is proposed. Based on the simulation of an industrial plant in the medium-voltage grid, which can provide reactive power in the form of industrial compensation systems (ICS) and generators, the operation of the algorithm is shown.}, language = {en} } @techreport{CasparDorfnerEngelmannetal., author = {Caspar, Stefan and Dorfner, Manuel and Engelmann, Uwe and Erhardsberger, Ludwig and Gressitzek, Tobias and Michelmann, Bj{\"o}rn and Steinberger, Melanie and Stuchl{\´y}, Jan}, title = {FMS-Berichte Sommersemester 2023}, number = {1}, editor = {Meier, Hans and Niemetz, Michael and Fuhrmann, Thomas and Reindl, Andrea}, address = {Regensburg}, organization = {Ostbayerische Technische Hochschule Regensburg / Fakult{\"a}t Elektro- und Informationstechnik}, doi = {10.35096/othr/pub-7778}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-77787}, pages = {44}, abstract = {Dieser Bericht entstand urspr{\"u}nglich auf Initiative der Studierenden des damals neuen Masterstudiengangs „Elektro- und Informationstechnik (MEI)" an der OTH Regensburg, die an der Pflichtlehrveranstaltung „Forschungsmethoden und Seminar (FMS)" im Wintersemester 2020/21 teilnahmen. Diese Lehrveranstaltung hat das Ziel, systematisch an das wissenschaftliche Arbeiten, speziell die Wissenschaftskommunikation, heranzuf{\"u}hren. Daher ist im Laufe der Veranstaltung geeignete Literatur zu einem individuellen Thema zu recherchieren, sind Ver{\"o}ffentlichungen auf ihre Relevanz hin zu beurteilen und letztendlich gilt es eine eigene Ausarbeitung basierend auf der Literaturrecherche zu erstellen und diese in einem Vortrag zu pr{\"a}sentieren. Parallel dazu wird im Theorieteil die entsprechende Hinf{\"u}hrung zu den verschiedenen Elementen der Wissenschaftskommunikation vermittelt: • Bedeutung der Wissenschaftskommunikation f{\"u}r die Arbeit der Ingenieure in Forschung und Entwicklung • Literaturrecherche, Suchmaschinen, Sichtung und Analyse vorhandener Publikationen, Bewertung der Qualit{\"a}t aufgefundener Fachliteratur, Auswahl geeigneter Materialien f{\"u}r die eigene Arbeit • Aufbereitung und Darstellung der recherchierten technischer Inhalte in Form einer seitenanzahlbegrenzten wissenschaftlichen Ausarbeitung • Einhalten formaler Randbedingungen bzgl. Strukturierung, einschl. Bildnachweise und Zitationsstile • Peer-review-Prozess bei wertsch{\"a}tzender Beurteilung der Leistung anderer • Publikumsangepasstes Aufbereiten komplexer fachlicher Inhalte mit hochschul{\"o}ffentlicher Pr{\"a}sentation der Ergebnisse • F{\"u}hren m{\"u}ndlicher wissenschaftlicher Diskurse Die pr{\"a}sentierten Themen beruhen nicht auf eigener Forschungst{\"a}tigkeit, sondern sind als einf{\"u}hrende Reviewartikel zum jeweiligen vorgegebenen technischen oder gesellschaftspolitischen Forschungsthema zu verstehen.}, subject = {Elektrotechnik}, language = {mul} } @article{HofrichterRankHeberletal., author = {Hofrichter, Andreas and Rank, Daniel and Heberl, Michael and Sterner, Michael}, title = {Determination of the optimal power ratio between electrolysis and renewable energy to investigate the effects on the hydrogen production costs}, series = {International Journal of Hydrogen Energy}, volume = {48}, journal = {International Journal of Hydrogen Energy}, number = {5}, publisher = {Elsevier}, issn = {0360-3199}, doi = {10.1016/j.ijhydene.2022.09.263}, pages = {1651 -- 1663}, abstract = {Green hydrogen via renewable powered electrolysis has a high relevance in decarbonization and supply security. Achieving economically competitive hydrogen production costs is a major challenge in times of an energy price crisis. Our objective is to show the economically optimal installed capacity of electrolysers in relation to wind and solar power so swift and credible statements can be made regarding the system design. The ratio between renewable generation and electrolysis power as well as scaling effects, operating behaviour and development of costs are considered. Hydrogen production costs are calculated for four exemplary real PV and wind sites and different ratios of electrolysis to renewable power for the year 2020. The ideal ratio for PV systems is between 14\% and 73\% and for wind between 3.3\% and 143\% for low and high full load hours. The lowest hydrogen production costs are identified at 2.53 €/kg for 50 MW wind power and 72 MW electrolysis power. The results provide plant constructors the possibility to create a cost-optimized design via an optimum ratio of electrolysis to renewable capacity. Therefore, the procedures for planning and dimensioning of selected systems can be drastically simplified.}, language = {en} }