TY - JOUR A1 - Dubberke, Frithjof H. A1 - Linnemann, Matthias A1 - Abbas, Wameedh Khider A1 - Baumhögger, Elmar A1 - Priebe, Klaus-Peter A1 - Roedder, Maximilian A1 - Neef, Matthias A1 - Vrabec, Jadran T1 - Experimental setup of a cascaded two-stage organic Rankine cycle JF - Applied Thermal Engineering N2 - In combination with a bottoming cycle, operated with a pure fluid in transcritical mode, the usage of a zeotropic mixture as a working fluid appears to be exergetically favorable for power cycle efficiency in cascaded two-stage organic Rankine cycles (CORC). A CORC is set up and initially tested with cyclopentane and propane as working fluids in its high temperature and low temperature cycle, respectively. A thermal oil cycle serves as the heat source and is powered electrically with a maximum heat flow of 158 kW. The design of this experimental setup allows for a rapid replacement of individual components and for a wide range of conditions in terms of fluids and thermodynamic states. The components of all cycles and the measurement and control technology are described in detail. A testing procedure is presented, followed by a discussion of the measurement results, where it is shown that the intended concept of two cascaded organic Rankine cycles is operational and that the measured data are consistent. KW - organic Rankine cycle KW - cascade KW - multicomponent working fluid KW - temperature-glide KW - pinch point KW - exergetice efficiency Y1 - 2018 U6 - https://doi.org/10.1016/j.applthermaleng.2017.11.137 VL - 131 SP - 958 EP - 964 PB - Elsevier ER - TY - CHAP A1 - Neef, Matthias A1 - Fussenecker, Claudia A1 - Niemann, Jörg A1 - Zielke, Thomas ED - Clark, Robin ED - Munkebo Hussmann, Peter ED - Järvinen, Hannu-Matti T1 - Publish your undergraduate research! A mandatory course for master students in engineering T2 - Creativity, innovation and entrepreneurship for engineering education excellence : proceedings of the 46th SEFI Annual Conference 2018, Copenhagen, Denmark N2 - Undergraduate students in engineering often have little exposure to the world of scientific publishing and the culture of sharing research work. While the beneficial exchange between research and teaching is well promoted, while the benefits of conference participation for students have already been surveyed and while courses on scientific writing are readily available, the concept of mini-conferences as part of the curriculum combines all three aspects into one. Therefore, the course "Engineering Conferences" was developed and installed as a mandatory part of a master program for engineering students. The idea is to go beyond simply teaching the standards of academic writing and skills for using scientific publications. By using a learner-centered approach, the students are engaged in typical activities around an active attendance of a real conference. Based on their bachelor thesis, they write a paper complying with common academic standards, submit the paper and review submissions of their fellow students. They also produce a poster and defend their work in a poster session held publicly on campus. This contribution is based on the experience from the first four terms teaching the course. It explains the didactic rationale behind the concept and individual teaching modules, it comprises the collection of useful resources for teaching and organizing scientific publishing and it includes the consequences drawn from course evaluation results. Y1 - 2018 SN - 978-2-87352-016-8 PB - SEFI - Société Européenne pour la Formation des Ingénieurs CY - Brussels ER - TY - JOUR A1 - Feseker, Daniel A1 - Kinell, Mats A1 - Neef, Matthias T1 - Experimental Study on Pressure Losses in Circular Orifices With Inlet Cross Flow JF - Journal of Turbomachinery N2 - The ability to understand and predict the pressure losses of orifices is important in order to improve the air flow within the secondary air system. This experimental study investigates the behavior of the discharge coefficient for circular orifices with inlet cross flow which is a common flow case in gas turbines. Examples of this are at the inlet of a film cooling hole or the feeding of air to a blade through an orifice in a rotor disk. Measurements were conducted for a total number of 38 orifices, covering a wide range of length-to-diameter ratios, including short and long orifices with varying inlet geometries. Up to five different chamfer-to-diameter and radius-to-diameter ratios were tested per orifice length. Furthermore, the static pressure ratio across the orifice was varied between 1.05 and 1.6 for all examined orifices. The results of this comprehensive investigation demonstrate the beneficial influence of rounded inlet geometries and the ability to decrease pressure losses, which is especially true for higher cross flow ratios where the reduction of the pressure loss in comparison to sharp-edged holes can be as high as 54%. With some exceptions, the chamfered orifices show a similar behavior as the rounded ones but with generally lower discharge coefficients. Nevertheless, a chamfered inlet yields lower pressure losses than a sharp-edged inlet. The obtained experimental data were used to develop two correlations for the discharge coefficient as a function of geometrical as well as flow properties. KW - Compressor KW - Gas turbine engines KW - Turbine components KW - Boundary layer development KW - Fluid dynamics KW - Heat transfer KW - Measurement techniques KW - Film cooling KW - Heat transfer phenomena Y1 - 2018 U6 - https://doi.org/10.1115/1.4039842 VL - 140 IS - 7 CY - ASME ER - TY - GEN A1 - Frank, Lena A1 - Rödder, Maximilian A1 - Neef, Matthias A1 - Adam, Mario T1 - Heizung, Lüftung, Weiße Ware - Ein integriertes Systemkonzept für das Haus der Zukunft T2 - KI Kälte Luft Klimatechnik N2 - In energieeffizienten Gebäuden spielt der Bedarf an Energie für die Raumheizung gegenüber der benötigten Energie für Warmwasser und zum Antrieb elektrischer Geräte eine zusehends untergeordnete Rolle. Die thermische Energie für elektrische Haushalts­geräte, wie Waschmaschine, Kühlschrank etc., wird für gewöhnlich dezentral im Gerät erzeugt. Vor diesem Hintergrund ist das Ziel eines Forschungsprojekts der Bau und der Test eines Funktionsmusters zur funktionalen und energetischen Kopplung der Haushaltsgeräte und der Heizungs- und Lüftungstechnik des Gebäudes. Grundgedanke dabei ist die Nutzung von Synergien bei Komponenten und Wärmeströmen, wie der Wärmepumpe als Kälteaggregat für den Kühlschrank, und die effiziente Nutzung von Abwärme der Haushaltsgeräte für die Warmwasserbereitung und Raumheizung. KW - Energieeffizienz KW - energiBUS4home Y1 - 2018 SN - 1865-5432 VL - 54 IS - 11 SP - 50 EP - 56 PB - Hüthig ER - TY - CHAP A1 - Kramer, Tim A1 - Lerner, Igor A1 - Sacher, Patrick A1 - Neef, Matthias A1 - Baier, André ED - Dederichs-Koch, Andrea ED - Mohnert, Andrea ED - Kammasch, Gudrun T1 - Blue Engineering: Was ist das und wie gelingt die Implementierung an meiner Hochschule? T2 - Diversität und Kulturelle Vielfalt - Differenzieren, Individualisieren - oder Integrieren? Wege zu technischer Bildung : Referate der 13. Ingenieurpädagogischen Regionaltagung 2018 and der Hochschule Bochum vom 7.-9. Juni 2018 KW - Blue Engineering KW - Diversität Y1 - 2018 SN - 978-3-9818728-2-8 PB - Ingenieur-Pädagogische Wissensgesellschaft (IPW) CY - Berlin ER - TY - CHAP A1 - Neef, Matthias A1 - aus der Wiesche, Stefan ED - aus der Wiesche, Stefan ED - Joos, Franz T1 - Aufbau und Wirkungsweise von Dampfturbinen: Grundlagen, Konstruktion, Betrieb T2 - Handbuch Dampfturbinen KW - Turbinen Y1 - 2018 SN - 978-3-658-20629-1 U6 - https://doi.org/10.1007/978-3-658-20630-7_2 SP - 27 EP - 83 PB - Springer Vieweg CY - Wiesbaden ER - TY - JOUR A1 - Rödder, Maximilian A1 - Frank, Lena A1 - Kirschner, Daniel A1 - Neef, Matthias A1 - Adam, Mario T1 - EnergiBUS4home – Sustainable energy resourcing in low-energy buildings JF - Energy KW - energiBUS4home Y1 - 2018 U6 - https://doi.org/10.1016/j.energy.2018.06.145 N1 - PII: S0360544218312106 VL - 159 SP - 638 EP - 647 PB - Elsevier ER - TY - GEN A1 - Frank, Lena A1 - Rödder, Maximilian A1 - Neef, Matthias A1 - Adam, Mario T1 - Heizung, Lüftung, Weiße Ware – Ein integriertes Systemkonzept für das Haus der Zukunft T2 - KKA – Kälte Klima Aktuell KW - energiBUS4home Y1 - 2018 SN - 0722-4605 VL - 37 IS - 4 SP - 42 EP - 47 PB - Bauverl. BV ER -