TY - JOUR A1 - Reger, Vitali A1 - Kuhnhenne, Markus A1 - Hachul, Helmut A1 - Döring, Bernd A1 - Blanke, Tobias A1 - Göttsche, Joachim T1 - Plusenergiegebäude 2.0 in Stahlleichtbauweise JF - Stahlbau Y1 - 2019 U6 - http://dx.doi.org/10.1002/stab.201900034 SN - 1437-1049 (E-journal), 0038-9145 (print) VL - 88 IS - 6 SP - 522 EP - 528 PB - Ernst & Sohn CY - Berlin ER - TY - JOUR A1 - Wolisz, Henryk A1 - Schütz, Thomas A1 - Blanke, Tobias A1 - Hagenkamp, Markus A1 - Kohrn, Markus A1 - Wesseling, Mark A1 - Müller, Dirk T1 - Cost optimal sizing of smart buildings' energy system components considering changing end-consumer electricity markets JF - Energy Y1 - 2017 U6 - http://dx.doi.org/10.1016/j.energy.2017.06.025 VL - 137 SP - 715 EP - 728 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Reger, Vitali A1 - Kuhnhenne, Markus A1 - Ebbert, Thiemo A1 - Hachul, Helmut A1 - Blanke, Tobias A1 - Döring, Bernd T1 - Nutzung erneuerbarer Energien durch thermische Aktivierung von Komponenten aus Stahl JF - Stahlbau N2 - Die Versorgung von Neubauten soll möglichst weitgehend unabhängig von fossilen Energieträgern erfolgen. Erneuerbare Energien spielen dafür eine gewichtige Rolle. Eine gute Möglichkeit, erneuerbare Energien ohne viel zusätzlichen Aufwand nutzbar zu machen, ist, bereits vorhandenen Komponenten im Gebäude zusätzliche Funktionen zu geben. Hier kann bspw. die Fassade oder das Dach solarthermisch aktiviert oder durch Fotovoltaikmodule ergänzt werden. Auch Tiefgründungen können neben der statischen Funktion noch eine geothermische Funktion zur Aufnahme oder Abgabe von Wärme erhalten. Neben der Erzeugung bietet sich auch für die Verteilung der Wärme oder Kälte im Gebäude die Integration in Bauteile an. Hier kann bspw. der Boden durch eine Fußbodenheizung oder die Decke durch Deckenstrahlplatten aktiviert werden. Im Rahmen der Veröffentlichung wird auf die thermische Aktivierung von Stahlkomponenten eingegangen. Es wird eine Lösung vorgestellt, die vorgehängte hinterlüftete Stahlfassade (VHF) solarthermisch zu aktivieren. Außerdem werden zwei Möglichkeiten zur geothermischen Aktivierung von Tiefgründungen mittels Stahlpfählen gezeigt. Zuletzt wird ein System zur thermischen Aktivierung von Stahltrapezprofilen an der Decke erläutert, welches Wärme zuführen oder bei Bedarf abführen kann. Y1 - 2020 U6 - http://dx.doi.org/10.1002/stab.202000031 SN - 1437-1049 VL - 2020 IS - Volume 89, Issue 6512-519 SP - 512 EP - 519 PB - Ernst & Sohn CY - Berlin ER - TY - JOUR A1 - Blanke, Tobias A1 - Hagenkamp, Markus A1 - Döring, Bernd A1 - Göttsche, Joachim A1 - Reger, Vitali A1 - Kuhnhenne, Markus T1 - Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates JF - Geothermal Energy N2 - Previous studies optimized the dimensions of coaxial heat exchangers using constant mass fow rates as a boundary condition. They show a thermal optimal circular ring width of nearly zero. Hydraulically optimal is an inner to outer pipe radius ratio of 0.65 for turbulent and 0.68 for laminar fow types. In contrast, in this study, fow conditions in the circular ring are kept constant (a set of fxed Reynolds numbers) during optimization. This approach ensures fxed fow conditions and prevents inappropriately high or low mass fow rates. The optimization is carried out for three objectives: Maximum energy gain, minimum hydraulic efort and eventually optimum net-exergy balance. The optimization changes the inner pipe radius and mass fow rate but not the Reynolds number of the circular ring. The thermal calculations base on Hellström’s borehole resistance and the hydraulic optimization on individually calculated linear loss of head coefcients. Increasing the inner pipe radius results in decreased hydraulic losses in the inner pipe but increased losses in the circular ring. The net-exergy diference is a key performance indicator and combines thermal and hydraulic calculations. It is the difference between thermal exergy fux and hydraulic efort. The Reynolds number in the circular ring is instead of the mass fow rate constant during all optimizations. The result from a thermal perspective is an optimal width of the circular ring of nearly zero. The hydraulically optimal inner pipe radius is 54% of the outer pipe radius for laminar fow and 60% for turbulent fow scenarios. Net-exergetic optimization shows a predominant infuence of hydraulic losses, especially for small temperature gains. The exact result depends on the earth’s thermal properties and the fow type. Conclusively, coaxial geothermal probes’ design should focus on the hydraulic optimum and take the thermal optimum as a secondary criterion due to the dominating hydraulics. Y1 - 2021 U6 - http://dx.doi.org/10.1186/s40517-021-00201-3 SN - 2195-9706 N1 - Corresponding author: Tobias Blanke VL - 9 IS - Article number: 19 PB - Springer CY - Berlin ER - TY - JOUR A1 - Hagenkamp, Markus A1 - Blanke, Tobias A1 - Döring, Bernd T1 - Thermoelectric building temperature control: a potential assessment JF - International Journal of Energy and Environmental Engineering N2 - This study focuses on thermoelectric elements (TEE) as an alternative for room temperature control. TEE are semi-conductor devices that can provide heating and cooling via a heat pump effect without direct noise emissions and no refrigerant use. An efficiency evaluation of the optimal operating mode is carried out for different numbers of TEE, ambient temperatures, and heating loads. The influence of an additional heat recovery unit on system efficiency and an unevenly distributed heating demand are examined. The results show that TEE can provide heat at a coefficient of performance (COP) greater than one especially for small heating demands and high ambient temperatures. The efficiency increases with the number of elements in the system and is subject to economies of scale. The best COP exceeds six at optimal operating conditions. An additional heat recovery unit proves beneficial for low ambient temperatures and systems with few TEE. It makes COPs above one possible at ambient temperatures below 0 ∘C. The effect increases efficiency by maximal 0.81 (from 1.90 to 2.71) at ambient temperature 5 K below room temperature and heating demand Q˙h=100W but is subject to diseconomies of scale. Thermoelectric technology is a valuable option for electricity-based heat supply and can provide cooling and ventilation functions. A careful system design as well as an additional heat recovery unit significantly benefits the performance. This makes TEE superior to direct current heating systems and competitive to heat pumps for small scale applications with focus on avoiding noise and harmful refrigerants. Y1 - 2021 U6 - http://dx.doi.org/10.1007/s40095-021-00424-x N1 - Corresponding author: Markus Hagenkamp VL - 13 SP - 241 EP - 254 PB - Springer CY - Berlin ER - TY - JOUR A1 - Blanke, Tobias A1 - Reger, Vitali A1 - Döring, Bernd A1 - Göttsche, Joachim A1 - Kuhnhenne, Markus T1 - Koaxiale Stahlenergiepfähle JF - Stahlbau N2 - Ein entscheidender Teil der Energiewende ist die Wärmewende im Gebäudesektor. Ein Schlüsselelement sind hier Wärmepumpen. Diese benötigen eine Wärmequelle, der sie Energie entziehen können, um sie auf ein höheres Temperaturniveau zu transformieren. Diese Wärmequelle kann bspw. das Erdreich sein, dessen Wärme durch Erdsonden erschlossen werden kann. In diesem Beitrag werden in Stahlpfähle integrierte Koaxialsonden mit dem Stand der Technik von Erdsonden gleichen Durchmessers bezüglich ihrer thermischen Leistungsmerkmale verglichen. Die Stahlenergiepfähle bieten neben der Wärmegewinnung weitere Vorteile, da sie auch eine statische Funktion übernehmen und rückstandsfrei zurückgebaut werden können. Es werden analytische und numerische Berechnungen vorgestellt, um die thermischen Potenziale beider Systeme zu vergleichen. Außerdem wird ein Testaufbau gezeigt, bei dem Stahlenergiepfähle in zwei verschiedenen Längen mit vorhandenen gängigen Erdsonden verglichen werden können. Die Berechnungen zeigen einen deutlichen thermischen Mehrertrag zwischen 26 % und 148 % der Stahlenergiepfähle gegenüber dem Stand der Technik abhängig vom Erdreich. Die Messergebnisse zeigen einen thermischen Mehrertrag von über 100 %. Es lässt sich also signifikante Erdsondenlänge einsparen. Dabei ist zu beachten, dass sich damit der thermisch genutzte Bereich des Erdreichs reduziert, wodurch die thermische Regeneration und/oder das Langzeitverhalten des Erdreichs an Bedeutung gewinnt. Y1 - 2021 VL - 90. 2021 IS - 6 SP - 417 EP - 424 PB - Wiley CY - Weinheim ER - TY - CHAP A1 - Blanke, Tobias A1 - Schmidt, Katharina S. A1 - Göttsche, Joachim A1 - Döring, Bernd A1 - Frisch, Jérôme A1 - van Treeck, Christoph ED - Weidlich, Anke ED - Neumann, Dirk ED - Gust, Gunther ED - Staudt, Philipp ED - Schäfer, Mirko T1 - Time series aggregation for energy system design: review and extension of modelling seasonal storages T2 - Energy Informatics N2 - 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. KW - Energy system KW - Renewable energy KW - Mixed integer linear programming (MILP) KW - Typical periods KW - Time-series aggregation Y1 - 2022 U6 - http://dx.doi.org/10.1186/s42162-022-00208-5 SN - 2520-8942 N1 - Proceedings of the 11th DACH+ Conference on Energy Informatics, 15-16 September 2022, Freiburg, Germany. VL - 5 IS - 1, Article number: 17 SP - 1 EP - 14 PB - Springer Nature ER - TY - CHAP A1 - Schulze-Buxloh, Lina A1 - Groß, Rolf Fritz T1 - Miniature urban farming plant: a complex educational “Toy” for engineering students T2 - The Future of Education 11th Edition 2021 N2 - 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. KW - urban farming KW - food production KW - smart engineering KW - 3D printing KW - sustainability Y1 - 2021 N1 - FOE 2021 : The Future of Education International Conference – Fully Virtual Edition; 01.07.2021-02.07.2021; Florence, Italy ER - TY - CHAP A1 - Mohan, Nijanthan A1 - Groß, Rolf Fritz A1 - Menzel, Karsten A1 - Theis, Fabian T1 - 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 T2 - WIT Transactions on The Built Environment, Vol. 205 N2 - 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. KW - building information modelling KW - HVAC KW - prefabrication KW - construction KW - small and medium scaled companies Y1 - 2021 U6 - http://dx.doi.org/10.2495/BIM210101 SN - 1743-3509 N1 - 4th International Conference on Building Information Modelling (BIM) in Design, Construction and Operations, 1–3 September 2021. Santiago de Compostela, Spain SP - 117 EP - 126 PB - WIT Press CY - Southampton ER - TY - RPRT A1 - Ayar, A. A1 - Fielenbach, C. A1 - Groß, Rolf Fritz A1 - Holfeld, T. A1 - Lockemann, S. A1 - Severin, C. A1 - Thulfaut, Christian A1 - Hillemacher, B. T1 - Druckkohlenstaubverbrennung von rheinischer Braunkohle : Abschlussbericht T1 - Pressure combustion of rhenish brown coal : final report N2 - 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. N2 - NOx formation and reduction in the coal combustion process was investigated both experimentally and theoretically. The influence of coal grain size described in earlier publications was proved by the measurements at the DKSF test facility at Aachen. While no pressure dependence was established so far for lignite, measurements on Spitzbergen coal at 9 - 13 bar showed a decrease in NOx concentrations with increasing pressure. This effect will be investigated for Rhenish brown coal in further experiments. Modelling by the standard FLUENT code and by the user defined subroutines of the FLUENT code developed by the International Flame Research Foundation (IFRF), Ijmuiden, showed that the different predictions of flame temperatures have a decisive role in the modelling of NOx formation. A more accurate analysis of the NOx models as compared to ther measurements will be carried out in a melting chamber furnace with a stable flame. Additionally, measurements were carried out for investigating the kinetics of homogeneous gaseous phase reactions in flue gases, i.e. the thermal and additive-catalysed degradation of nitrous components was investigated. The kinetics of the process was also described by a code developed at Aachen University. On the base of a sensitivity analysis, a reduction of the detailed modelling of the reaction kinetics is achieved which permits 2D and 3D calculations on the decomposition of different flue gas components using a CFD code like FLUENT. The 1D and 2D calculations and the measurements were found to be in good agreement. Y1 - 2003 N1 - Druckkohlenstaubverbrennung von rheinischer Braunkohle Förderkennzeichen: 0327072 Abschlussbericht zum Forschungsvorhaben ausführende Stelle: Lehrstuhl fur Wärmeübertragung und Klimatechnik der RWTH Aachen Professor Dr.-Ing. U. Renz ER -