@article{HoffstadtCheenakulaNikolauszetal.2023,
  author    = {Hoffstadt, Kevin and Cheenakula, Dheeraja and Nikolausz, Marcell and Krafft, Simone and Harms, Hauke and Kuperjans, Isabel},
  title     = {Design and construction of a new reactor for flexible biomethanation of hydrogen},
  series = {Fermentation},
  volume    = {9},
  journal   = {Fermentation},
  number    = {8},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2311-5637},
  doi       = {10.3390/fermentation9080774},
  pages     = {1 -- 16},
  year      = {2023},
  abstract  = {The increasing share of renewable electricity in the grid drives the need for sufficient storage capacity. Especially for seasonal storage, power-to-gas can be a promising approach. Biologically produced methane from hydrogen produced from surplus electricity can be used to substitute natural gas in the existing infrastructure. Current reactor types are not or are poorly optimized for flexible methanation. Therefore, this work proposes a new reactor type with a plug flow reactor (PFR) design. Simulations in COMSOL Multiphysics ® showed promising properties for operation in laminar flow. An experiment was conducted to support the simulation results and to determine the gas fraction of the novel reactor, which was measured to be 29\%. Based on these simulations and experimental results, the reactor was constructed as a 14 m long, 50 mm diameter tube with a meandering orientation. Data processing was established, and a step experiment was performed. In addition, a kLa of 1 h-1 was determined. The results revealed that the experimental outcomes of the type of flow and gas fractions are in line with the theoretical simulation. The new design shows promising properties for flexible methanation and will be tested.},
  language  = {en}
}
@article{CheenakulaPaulsenOttetal.2023,
  author    = {Cheenakula, Dheeraja and Paulsen, Svea and Ott, Fabian and Gr{\"o}mping, Markus},
  title     = {Operational window of a deammonifying sludge for mainstream application in a municipal wastewater treatment plant},
  series = {Water and Environment Journal},
  volume    = {38},
  journal   = {Water and Environment Journal},
  number    = {1},
  publisher = {Wiley},
  address   = {Chichester},
  issn      = {1747-6593},
  doi       = {10.1111/wej.12898},
  pages     = {59 -- 70},
  year      = {2023},
  abstract  = {The present work aimed to study the mainstream feasibility of the deammonifying sludge of side stream of municipal wastewater treatment plant (MWWTP) in Kaster, Germany. For this purpose, the deammonifying sludge available at the side stream was investigated for nitrogen (N) removal with respect to the operational factors temperature (15-30°C), pH value (6.0-8.0) and chemical oxygen demand (COD)/N ratio (≤1.5-6.0). The highest and lowest N-removal rates of 0.13 and 0.045 kg/(m³ d) are achieved at 30 and 15°C, respectively. Different conditions of pH and COD/N ratios in the SBRs of Partial nitritation/anammox (PN/A) significantly influenced both the metabolic processes and associated N-removal rates. The scientific insights gained from the current work signifies the possibility of mainstream PN/A at WWTPs. The current study forms a solid basis of operational window for the upcoming semi-technical trails to be conducted prior to the full-scale mainstream PN/A at WWTP Kaster and WWTPs globally.},
  language  = {en}
}
@article{CheenakulaGriebelMontagetal.2023,
  author    = {Cheenakula, Dheeraja and Griebel, Kai and Montag, David and Gr{\"o}mping, Markus},
  title     = {Concept development of a mainstream deammonification and comparison with conventional process in terms of energy, performance and economical construction perspectives},
  series = {Frontiers in Microbiology},
  volume    = {14},
  journal   = {Frontiers in Microbiology},
  number    = {11155235},
  editor    = {Huang, Xiaowu},
  publisher = {Frontiers},
  issn      = {1664-302X},
  doi       = {10.3389/fmicb.2023.1155235},
  pages     = {1 -- 15},
  year      = {2023},
  abstract  = {Deammonification for nitrogen removal in municipal wastewater in temperate and cold climate zones is currently limited to the side stream of municipal wastewater treatment plants (MWWTP). This study developed a conceptual model of a mainstream deammonification plant, designed for 30,000 P.E., considering possible solutions corresponding to the challenging mainstream conditions in Germany. In addition, the energy-saving potential, nitrogen elimination performance and construction-related costs of mainstream deammonification were compared to a conventional plant model, having a single-stage activated sludge process with upstream denitrification. The results revealed that an additional treatment step by combining chemical precipitation and ultra-fine screening is advantageous prior the mainstream deammonification. Hereby chemical oxygen demand (COD) can be reduced by 80\% so that the COD:N ratio can be reduced from 12 to 2.5. Laboratory experiments testing mainstream conditions of temperature (8-20°C), pH (6-9) and COD:N ratio (1-6) showed an achievable volumetric nitrogen removal rate (VNRR) of at least 50 gN/(m3∙d) for various deammonifying sludges from side stream deammonification systems in the state of North Rhine-Westphalia, Germany, where m3 denotes reactor volume. Assuming a retained Norganic content of 0.0035 kgNorg./(P.E.∙d) from the daily loads of N at carbon removal stage and a VNRR of 50 gN/(m3∙d) under mainstream conditions, a resident-specific reactor volume of 0.115 m3/(P.E.) is required for mainstream deammonification. This is in the same order of magnitude as the conventional activated sludge process, i.e., 0.173 m3/(P.E.) for an MWWTP of size class of 4. The conventional plant model yielded a total specific electricity demand of 35 kWh/(P.E.∙a) for the operation of the whole MWWTP and an energy recovery potential of 15.8 kWh/(P.E.∙a) through anaerobic digestion. In contrast, the developed mainstream deammonification model plant would require only a 21.5 kWh/(P.E.∙a) energy demand and result in 24 kWh/(P.E.∙a) energy recovery potential, enabling the mainstream deammonification model plant to be self-sufficient. The retrofitting costs for the implementation of mainstream deammonification in existing conventional MWWTPs are nearly negligible as the existing units like activated sludge reactors, aerators and monitoring technology are reusable. However, the mainstream deammonification must meet the performance requirement of VNRR of about 50 gN/(m3∙d) in this case.},
  language  = {en}
}
@inproceedings{MaurerMiskiwAcostaetal.2023,
  author    = {Maurer, Florian and Miskiw, Kim K. and Acosta, Rebeca Ramirez and Harder, Nick and Sander, Volker and Lehnhoff, Sebastian},
  title     = {Market abstraction of energy markets and policies - application in an agent-based modeling toolbox},
  series = {EI.A 2023: Energy Informatics},
  booktitle = {EI.A 2023: Energy Informatics},
  editor    = {Jorgensen, Bo Norregaard and Pereira da Silva, Luiz Carlos and Ma, Zheng},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-031-48651-7 (Print)},
  doi       = {10.1007/978-3-031-48652-4_10},
  pages     = {139 -- 157},
  year      = {2023},
  abstract  = {In light of emerging challenges in energy systems, markets are prone to changing dynamics and market design. Simulation models are commonly used to understand the changing dynamics of future electricity markets. However, existing market models were often created with specific use cases in mind, which limits their flexibility and usability. This can impose challenges for using a single model to compare different market designs. This paper introduces a new method of defining market designs for energy market simulations. The proposed concept makes it easy to incorporate different market designs into electricity market models by using relevant parameters derived from analyzing existing simulation tools, morphological categorization and ontologies. These parameters are then used to derive a market abstraction and integrate it into an agent-based simulation framework, allowing for a unified analysis of diverse market designs. Furthermore, we showcase the usability of integrating new types of long-term contracts and over-the-counter trading. To validate this approach, two case studies are demonstrated: a pay-as-clear market and a pay-as-bid long-term market. These examples demonstrate the capabilities of the proposed framework.},
  language  = {en}
}
@article{CheenakulaHoffstadtKrafftetal.2022,
  author    = {Cheenakula, Dheeraja and Hoffstadt, Kevin and Krafft, Simone and Reinecke, Diana and Klose, Holger and Kuperjans, Isabel and Gr{\"o}mping, Markus},
  title     = {Anaerobic digestion of algal-bacterial biomass of an Algal Turf Scrubber system},
  series = {Biomass Conversion and Biorefinery},
  volume    = {13},
  journal   = {Biomass Conversion and Biorefinery},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {2190-6823},
  doi       = {10.1007/s13399-022-03236-z},
  pages     = {15 Seiten},
  year      = {2022},
  abstract  = {This study investigated the anaerobic digestion of an algal-bacterial biofilm grown in artificial wastewater in an Algal Turf Scrubber (ATS). The ATS system was located in a greenhouse (50°54′19ʺN, 6°24′55ʺE, Germany) and was exposed to seasonal conditions during the experiment period. The methane (CH4) potential of untreated algal-bacterial biofilm (UAB) and thermally pretreated biofilm (PAB) using different microbial inocula was determined by anaerobic batch fermentation. Methane productivity of UAB differed significantly between microbial inocula of digested wastepaper, a mixture of manure and maize silage, anaerobic sewage sludge, and percolated green waste. UAB using sewage sludge as inoculum showed the highest methane productivity. The share of methane in biogas was dependent on inoculum. Using PAB, a strong positive impact on methane productivity was identified for the digested wastepaper (116.4\%) and a mixture of manure and maize silage (107.4\%) inocula. By contrast, the methane yield was significantly reduced for the digested anaerobic sewage sludge (50.6\%) and percolated green waste (43.5\%) inocula. To further evaluate the potential of algal-bacterial biofilm for biogas production in wastewater treatment and biogas plants in a circular bioeconomy, scale-up calculations were conducted. It was found that a 0.116 km2 ATS would be required in an average municipal wastewater treatment plant which can be viewed as problematic in terms of space consumption. However, a substantial amount of energy surplus (4.7-12.5 MWh a-1) can be gained through the addition of algal-bacterial biomass to the anaerobic digester of a municipal wastewater treatment plant. Wastewater treatment and subsequent energy production through algae show dominancy over conventional technologies.},
  language  = {en}
}
@book{Pieper2021,
  author    = {Pieper, Martin},
  title     = {Quantum mechanics: Introduction to mathematical formulation},
  publisher = {Springer},
  address   = {Wiesbaden},
  isbn      = {978-3-658-32644-9},
  doi       = {10.1007/978-3-658-32645-6},
  pages     = {XIII, 33},
  year      = {2021},
  abstract  = {Anyone who has always wanted to understand the hieroglyphs on Sheldon's blackboard in the TV series The Big Bang Theory or who wanted to know exactly what the fate of Schr{\"o}dinger's cat is all about will find a short, descriptive introduction to the world of quantum mechanics in this essential. The text particularly focuses on the mathematical description in the Hilbert space. The content goes beyond popular scientific presentations, but is nevertheless suitable for readers without special prior knowledge thanks to the clear examples.},
  language  = {en}
}
@incollection{JordanKatzPieper2021,
  author    = {Jordan, Frank and Katz, Christiane and Pieper, Martin},
  title     = {Online-Kollaboration in der Mathematik: Ein Design-Based-Research-Projekt},
  series = {Forschungsimpulse f{\"u}r hybrides Lehren und Lernen an Hochschulen},
  booktitle = {Forschungsimpulse f{\"u}r hybrides Lehren und Lernen an Hochschulen},
  publisher = {TH K{\"o}ln},
  address   = {K{\"o}ln},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:832-cos4-9465},
  pages     = {245 -- 261},
  year      = {2021},
  abstract  = {Die Studie er{\"o}rtert anhand eines Fallbeispiels aus der Mathematik f{\"u}r Ingenieur*innen, wie didaktische Gestaltungsprinzipien f{\"u}r Soziale Pr{\"a}senz, Kollaboration und das L{\"o}sen von praxisnahen Problemen mit mathematischem Denken in einer Online-Umgebung aussehen k{\"o}nnen. Hierf{\"u}r zieht der Beitrag den forschungsmethodologischen Rahmen Design-Based Research (DBR) hinzu und berichtet {\"u}ber Zwischenergebnisse. DBR wird an dieser Stelle als eine systematische Herangehensweise an kurzfristige Lehrver{\"a}nderungen und als Chance auf dem Weg zu einer neuen Hochschullehre nach der COVID-19-Pandemie dargestellt, die theoretische und empirische Erkenntnisse mit Praxisverkn{\"u}pfung und -relevanz vereint.},
  language  = {de}
}
@inproceedings{HandschuhStollenwerkBorchert2021,
  author    = {Handschuh, Nils and Stollenwerk, Dominik and Borchert, J{\"o}rg},
  title     = {Operation of thermal storage power plants under high renewable grid penetration},
  series = {NEIS 2021: Conference on Sustainable Energy Supply and Energy Storage Systems},
  booktitle = {NEIS 2021: Conference on Sustainable Energy Supply and Energy Storage Systems},
  publisher = {VDE Verlag},
  address   = {Berlin},
  isbn      = {978-3-8007-5651-3},
  pages     = {261 -- 265},
  year      = {2021},
  abstract  = {The planned coal phase-out in Germany by 2038 will lead to the dismantling of power plants with a total capacity of approx. 30 GW. A possible further use of these assets is the conversion of the power plants to thermal storage power plants; the use of these power plants on the day-ahead market is considerably limited by their technical parameters. In this paper, the influence of the technical boundary conditions on the operating times of these storage facilities is presented. For this purpose, the storage power plants were described as an MILP problem and two price curves, one from 2015 with a relatively low renewable penetration (33 \%) and one from 2020 with a high renewable energy penetration (51 \%) are compared. The operating times were examined as a function of the technical parameters and the critical influencing factors were investigated. The thermal storage power plant operation duration and the energy shifted with the price curve of 2020 increases by more than 25 \% compared to 2015.},
  language  = {en}
}
@article{GeorgStollenwerkReinkensmeieretal.2021,
  author    = {Georg, J{\"o}rg Heiner and Stollenwerk, Dominik and Reinkensmeier, Sebastian and Jungbluth, Christian},
  title     = {„Smartes" Laden an {\"o}ffentlich zug{\"a}nglichen Lades{\"a}ulen - Teil 1: Quo vadis, Marktdesign?},
  series = {Energiewirtschaftliche Tagesfragen : et ; Zeitschrift f{\"u}r Energiewirtschaft, Recht, Technik und Umwelt},
  volume    = {71},
  journal   = {Energiewirtschaftliche Tagesfragen : et ; Zeitschrift f{\"u}r Energiewirtschaft, Recht, Technik und Umwelt},
  number    = {1/2},
  publisher = {ETV Energieverlag},
  address   = {Essen},
  isbn      = {0720-6240},
  issn      = {0013-743X},
  pages     = {64 -- 69},
  year      = {2021},
  language  = {de}
}
@article{StollenwerkReinkensmeierGeorgetal.2021,
  author    = {Stollenwerk, Dominik and Reinkensmeier, Sebastian and Georg, J{\"o}rg Heiner and Jungbluth, Christian},
  title     = {„Smartes" Laden an {\"o}ffentlich zug{\"a}nglichen Lades{\"a}ulen - Teil 2: USER-Verhalten und -Erwartungen},
  series = {Energiewirtschaftliche Tagesfragen : et ; Zeitschrift f{\"u}r Energiewirtschaft, Recht, Technik und Umwelt},
  volume    = {71},
  journal   = {Energiewirtschaftliche Tagesfragen : et ; Zeitschrift f{\"u}r Energiewirtschaft, Recht, Technik und Umwelt},
  number    = {3},
  publisher = {ETV Energieverlag},
  address   = {Essen},
  isbn      = {0720-6240},
  issn      = {0013-743X},
  pages     = {38 -- 42},
  year      = {2021},
  language  = {de}
}