@incollection{Peterson2021, author = {Peterson, Leif Arne}, title = {Holzbau}, series = {Wof{\"u}r braucht man das eigentlich? Ein Handbuch f{\"u}r Mathematiklehrkr{\"a}fte der Sekundarstufe I und II}, booktitle = {Wof{\"u}r braucht man das eigentlich? Ein Handbuch f{\"u}r Mathematiklehrkr{\"a}fte der Sekundarstufe I und II}, editor = {Schl{\"u}ter, Dominik}, publisher = {BoD}, address = {Norderstedt}, isbn = {978-3-7543-2606-0}, pages = {21 -- 23}, year = {2021}, language = {de} } @inproceedings{BlankeSchmidtGoettscheetal.2022, author = {Blanke, Tobias and Schmidt, Katharina S. and G{\"o}ttsche, Joachim and D{\"o}ring, Bernd and Frisch, J{\´e}r{\^o}me and van Treeck, Christoph}, title = {Time series aggregation for energy system design: review and extension of modelling seasonal storages}, series = {Energy Informatics}, volume = {5}, booktitle = {Energy Informatics}, number = {1, Article number: 17}, editor = {Weidlich, Anke and Neumann, Dirk and Gust, Gunther and Staudt, Philipp and Sch{\"a}fer, Mirko}, publisher = {Springer Nature}, issn = {2520-8942}, doi = {10.1186/s42162-022-00208-5}, pages = {1 -- 14}, year = {2022}, abstract = {Using optimization to design a renewable energy system has become a computationally demanding task as the high temporal fluctuations of demand and supply arise within the considered time series. The aggregation of typical operation periods has become a popular method to reduce effort. These operation periods are modelled independently and cannot interact in most cases. Consequently, seasonal storage is not reproducible. This inability can lead to a significant error, especially for energy systems with a high share of fluctuating renewable energy. The previous paper, "Time series aggregation for energy system design: Modeling seasonal storage", has developed a seasonal storage model to address this issue. Simultaneously, the paper "Optimal design of multi-energy systems with seasonal storage" has developed a different approach. This paper aims to review these models and extend the first model. The extension is a mathematical reformulation to decrease the number of variables and constraints. Furthermore, it aims to reduce the calculation time while achieving the same results.}, language = {en} } @inproceedings{SchulzeBuxlohGross2021, author = {Schulze-Buxloh, Lina and Groß, Rolf Fritz}, title = {Miniature urban farming plant: a complex educational "Toy" for engineering students}, series = {The Future of Education 11th Edition 2021}, booktitle = {The Future of Education 11th Edition 2021}, pages = {4 Seiten}, year = {2021}, abstract = {Urban farming is an innovative and sustainable way of food production and is becoming more and more important in smart city and quarter concepts. It also enables the production of certain foods in places where they usually dare not produced, such as production of fish or shrimps in large cities far away from the coast. Unfortunately, it is not always possible to show students such concepts and systems in real life as part of courses: visits of such industry plants are sometimes not possible because of distance or are permitted by the operator for hygienic reasons. In order to give the students the opportunity of getting into contact with such an urban farming system and its complex operation, an industrial urban farming plant was set up on a significantly smaller scale. Therefore, all needed technical components like water aeriation, biological and mechanical filtration or water circulation have been replaced either by aquarium components or by self-designed parts also using a 3D-printer. Students from different courses like mechanical engineering, smart building engineering, biology, electrical engineering, automation technology and civil engineering were involved in this project. This "miniature industrial plant" was also able to start operation and has now been running for two years successfully. Due to Corona pandemic, home office and remote online lectures, the automation of this miniature plant should be brought to a higher level in future for providing a good control over the system and water quality remotely. The aim of giving the student a chance to get to know the operation of an urban farming plant was very well achieved and the students had lots of fun in "playing" and learning with it in a realistic way.}, language = {en} } @inproceedings{MohanGrossMenzeletal.2021, author = {Mohan, Nijanthan and Groß, Rolf Fritz and Menzel, Karsten and Theis, Fabian}, title = {Opportunities and Challenges in the Implementation of Building Information Modeling for Prefabrication of Heating, Ventilation and Air Conditioning Systems in Small and Medium-Sized Contracting Companies in Germany - A Case Study}, series = {WIT Transactions on The Built Environment, Vol. 205}, booktitle = {WIT Transactions on The Built Environment, Vol. 205}, publisher = {WIT Press}, address = {Southampton}, issn = {1743-3509}, doi = {10.2495/BIM210101}, pages = {117 -- 126}, year = {2021}, abstract = {FEven though BIM (Building Information Modelling) is successfully implemented in most of the world, it is still in the early stages in Germany, since the stakeholders are sceptical of its reliability and efficiency. The purpose of this paper is to analyse the opportunities and obstacles to implementing BIM for prefabrication. Among all other advantages of BIM, prefabrication is chosen for this paper because it plays a vital role in creating an impact on the time and cost factors of a construction project. The project stakeholders and participants can explicitly observe the positive impact of prefabrication, which enables the breakthrough of the scepticism factor among the small-scale construction companies. The analysis consists of the development of a process workflow for implementing prefabrication in building construction followed by a practical approach, which was executed with two case studies. It was planned in such a way that, the first case study gives a first-hand experience for the workers at the site on the BIM model so that they can make much use of the created BIM model, which is a better representation compared to the traditional 2D plan. The main aim of the first case study is to create a belief in the implementation of BIM Models, which was succeeded by the execution of offshore prefabrication in the second case study. Based on the case studies, the time analysis was made and it is inferred that the implementation of BIM for prefabrication can reduce construction time, ensures minimal wastes, better accuracy, less problem-solving at the construction site. It was observed that this process requires more planning time, better communication between different disciplines, which was the major obstacle for successful implementation. This paper was carried out from the perspective of small and medium-sized mechanical contracting companies for the private building sector in Germany.}, 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} } @techreport{AyarFielenbachGrossetal.2003, author = {Ayar, A. and Fielenbach, C. and Groß, Rolf Fritz and Holfeld, T. and Lockemann, S. and Severin, C. and Thulfaut, Christian and Hillemacher, B.}, title = {Druckkohlenstaubverbrennung von rheinischer Braunkohle : Abschlussbericht}, pages = {119 Seiten}, year = {2003}, abstract = {Im Rahmen des Forschungsschwerpunkts 3 wurde experimentell und theoretisch die NO{sub x}-Bildung und -Reduktion bei der Druckkohlenstaubverbrennung untersucht. Der zuvor beschriebene Einfluss der Kohlemahlung auf die Flamme konnte auch anhand der NO{sub x}-Messungen an der DKSF-Anlage Aachen bestaetigt werden. Waehrend mit Braunkohle im Staubfeuerungsbetrieb noch keine eindeutige Druckabhaengigkeit nachgewiesen werden konnte, haben vom Lehrstuhl durchgefuehrte NO{sub x}-Messungen an der DKSF-Anlage Dorsten im Schmelzkammerfeuerungsbetrieb mit der Steinkohle Spitzbergen zwischen 9 und 13 bar ein Absinken der Stickoxidkonzentrationen mit steigendem Druck ergeben. Fuer die rheinische Braunkohle soll dieser Druckeinfluss in den naechsten Versuchsfahrten ausfuehrlicher untersucht werden. Es wurde anhand von numerischen Simulationen zu einer Braunkohleflamme der 6. Versuchsfahrt ein Vergleich zwischen der NO{sub x}-Modellierung im Standard-FLUENT-Code und in dem mit User Defined Subroutines der international flame research foundation (IFRF), Ijmuiden, erweiterten FLUENT-Code vorgenommen. Es zeigte sich, dass bei der Modellierung der Stickoxidbildung die unterschiedlich vorhergesagten Flammentemperaturen eine entscheidende Rolle spielen. Eine genauere Analyse der NO{sub x}-Modelle im Vergleich zu Messergebnissen ist bei einer Schmelzkammerfeuerung mit einer stabilen Flamme vorzunehmen. Es wurden zusaetzlich Messungen zur Untersuchung der Kinetik homogener Gasphasenreaktionen in Rauchgasen an einem Stahlreaktor durchgefuehrt. Dabei wurde sowohl der thermisch bedingte als auch der durch zudosierte Additive katalysierte Abbau nitroser Komponenten betrachtet. Vergleichend wurden mit einem am Lehrstuhl entwickelten Programm die Kinetik beschrieben. Hierbei wird mit einer Sensitivitaetsanalyse eine Reduzierung der detaillierten Darstellung der Reaktionskinetik erreicht, die es erlaubt, mit einem CFD-Code wie FLUENT zwei- und dreidimensionale Rechnungen zum Abbau verschiedener Rauchgaskomponenten durchzufuehren. Die Uebereinstimmung zwischen ein- und zweidimensionalen Rechnungen und den Messungen ist gut.}, language = {de} } @article{ThulfautGross2000, author = {Thulfaut, Christian and Groß, Rolf Fritz}, title = {Experimentelle Untersuchung der Luftstromvermischung in Hybridzellenk{\"u}hlt{\"u}rmen}, series = {HLH. Heizung, L{\"u}ftung/Klima, Haustechnik}, volume = {51}, journal = {HLH. Heizung, L{\"u}ftung/Klima, Haustechnik}, number = {8}, publisher = {Springer}, address = {D{\"u}sseldorf}, issn = {1436-5103}, pages = {48 -- 49}, year = {2000}, abstract = {Zwangsbel{\"u}ftete Nassk{\"u}hlt{\"u}rme haben im Gegensatz zur Trockenk{\"u}hlung bei naßkaltem Wetter Nebelschwaden zur Folge. Dagegen ist bei Naßk{\"u}hlung die spezifische K{\"u}hlleistung durch abgef{\"u}hrte Kondensationsw{\"a}rme h{\"o}her als bei der Trockenk{\"u}hlung. Hybridzellenk{\"u}hlt{\"u}rme kombinieren beide Methoden, so daß ein Mischstrom beider Abluftstr{\"o}me die Wasserdampf-S{\"a}ttigungsgrenze nicht {\"u}berschreitet. Durch das Mischungsverh{\"a}ltnis kann man den gew{\"u}nschten S{\"a}ttigungsgrad einstellen. Je dichter dieser an der S{\"a}ttigungsgrenze liegt, desto h{\"o}her ist die K{\"u}hlleistung. Der von unten zugef{\"u}hrte Luftstrom der Naßk{\"u}hlung und der seitlich zugef{\"u}hrte trockene Abluftstrom m{\"u}ssen sehr gut durchmischt werden, um {\"u}ber den gesamten Austrittsquerschnitt des K{\"u}hlturms die S{\"a}ttigungsgrenze nicht zu {\"u}berschreiten. In einem maßstabsgerechten Modell wurde der Mischungsgrad mit und ohne Einbauten untersucht. {\"U}ber ein Raster von 10 mal 10 Punkten wurde die {\"o}rtliche Temperaturverteilung ermittelt. W{\"a}rmebilanzen ergeben dann die Mischungsg{\"u}te in einer Ebene oberhalb der Zellenkrone. W{\"a}hrend ohne Mischeinbauten der Trockenluftanteil in der Mitte des Querschnitts bei unter 15 \% liegt erh{\"o}hen Einbauten den Trockenluftanteil auf 30 \% bis {\"u}ber 40 \%. Dabei wurde die Trockenluft auf jeder K{\"u}hlturmseite durch 4 konisch zulaufende, unten offene und oben geschlitzte Einbauten kanalisiert. Die Nassluft wurde durch eine im Querschnitt dreieckige Rinne in Richtung der Trockenluftausl{\"a}sse umgelenkt. Im Raster leicht zu lokalisierende Abweichungen vom gew{\"u}nschten Mittelwert zeigen Potential f{\"u}r die weitere Verbesserung der Einbauten.}, language = {de} } @incollection{GrossHeckenRenz1999, author = {Groß, Rolf Fritz and Hecken, M. and Renz, Ulrich}, title = {Hot gas filtration with ceramic filter candles: experimental and numerical investigations on fluid flow during element cleaning}, series = {High temperature gas cleaning. Vol. 2}, booktitle = {High temperature gas cleaning. Vol. 2}, editor = {Dittler, A. and Hemmer, G. and Kasper, G.}, publisher = {KIT Institut f{\"u}r Mechanische Verfahrenstechnik und Mechanik}, address = {Karlsruhe}, isbn = {3-9805220-1-6}, pages = {862 -- 873}, year = {1999}, abstract = {Ceramic hot gas filters are widely used in combined cycles based on pressurised fluidised beds. They fulfil most of the demands with respect to cleaning efficiency and long time durability, but their operation regarding the consumption of pulse gas and energy still has to be optimised. Experimental investigations were carried out to measure the flow field, the pressure and the gas temperature inside the filter candle during pulse jet cleaning. These results are compared with the results of a numerical procedure based on a solution of the two - dimensional conservation equations for momentum and energy. The observed difficulties handling different flow regimes like highly turbulent flow as well as Darcy flow simultaneously are discussed.}, language = {en} } @article{GrossTimmer1998, author = {Groß, Rolf Fritz and Timmer, H.}, title = {Energetische und betriebswirtschaftliche Bewertung von K{\"u}hlsystemen f{\"u}r K{\"u}hllager}, series = {HLH. Heizung, L{\"u}ftung/Klima, Haustechnik}, volume = {49}, journal = {HLH. Heizung, L{\"u}ftung/Klima, Haustechnik}, number = {9}, publisher = {Springer}, address = {D{\"u}sseldorf}, issn = {1436-5103}, pages = {74 -- 77}, year = {1998}, language = {de} } @incollection{ThulfautGrossRenz2000, author = {Thulfaut, Christian and Groß, Rolf Fritz and Renz, Ulrich}, title = {Messwerterfassung und -auswertung mit LabView: Experimentelle Analyse der Mischungsg{\"u}te in Hybridzellenk{\"u}hlt{\"u}rmen}, series = {Virtuelle Instrumente in der Praxis. Begleitband zum Kongress VIP 2000}, booktitle = {Virtuelle Instrumente in der Praxis. Begleitband zum Kongress VIP 2000}, editor = {Jamal, Rahman and Jaschinski, Hans}, publisher = {H{\"u}thig}, address = {Heidelberg}, isbn = {3-7785-2789-4 (print)}, pages = {54 -- 60}, year = {2000}, abstract = {Zur K{\"u}hlung von Abw{\"a}rmestr{\"o}men aus Kraftwerksprozessen werden in zunehmenden Maße Hybridzellenk{\"u}hlt{\"u}rme mit Zwangskonvektion eingesetzt, deren wesentlicher Vorteil ihre geringe Bauh{\"o}he ist. Um bei derartigen K{\"u}hlt{\"u}rmen eine Sichtbehinderung oder Glatteisgef{\"a}hrdung durch bodennahen Nebel zu vermeiden, muss durch eine optimale Vermischung des Trocken- und Naßluftanteils gew{\"a}hrleistet sein, daß aus der K{\"u}hlturmkrone keine Nebelschwaden austreten. In Zusammenarbeit mit der Industrie betreibt der Lehrstuhl f{\"u}r W{\"a}rme{\"u}bertragung und Klimatechnik der RWTH Aachen einen Versuchsstand zur Erfassung der Mischungsg{\"u}te in Hybridzellenk{\"u}hlt{\"u}rmen. In maßstabsgerechter Nachbildung k{\"o}nnen dabei am Modell alle relevanten Einflußgr{\"o}ßen wie K{\"u}hlturmgeometrie, Gestaltung zus{\"a}tzlicher Mischeinbauten sowie die Betriebsparameter variiert werden. Mit Hilfe einer unter LabView 5.01 erstellten Software werden sowohl die l3etriebszust{\"u}ncle online {\"u}berwacht, als auch die ben{\"o}tigten Meßwerte zur Bestimmung der Mischungsg{\"u}te erfaßt. {\"U}ber die grafische Oberfl{\"a}che k{\"o}nnen s{\"a}mtliche Meßoptionen gesteuert sowie alle Meßdaten visualisiert und kontrolliert werden. In das LabView-Programm sind dar{\"u}ber hinaus Routinen zur Auswertung der Daten implementiert worden, die sowohl eine direkte Darstellung der Ergebnisse in Form von Diagrammen erm{\"o}glichen, als auch zur Weiterverarbeitung einen Datenexport in eine Microsoft- Excel-Tabelle vorsehen.}, language = {de} }