@article{Deckert2008, author = {Deckert, Carsten}, title = {Vitaler Wissensaustausch}, series = {Wissensmanagement - Das Magazin f{\"u}r F{\"u}hrungskr{\"a}fte}, volume = {10}, journal = {Wissensmanagement - Das Magazin f{\"u}r F{\"u}hrungskr{\"a}fte}, number = {6}, pages = {44 -- 46}, year = {2008}, abstract = {Sch{\"a}tzungen zufolge besitzen ein Viertel bis ein Drittel der Mitarbeiter eines Unternehmens unverzichtbares Experten-Know-how. Keine Organisation kann es sich heutzutage leisten, dieses Wissen nicht oder auch nur unvollst{\"a}ndig zu nutzen. Dar{\"u}ber hinaus f{\"u}hrt der demografische Wandel in Deutschland dazu, dass dieses Wissen den Unternehmen zunehmend verloren geht, wenn sie keinen vitalen Wissensaustausch betreiben.}, language = {de} } @article{Deckert2010, author = {Deckert, Carsten}, title = {Innovation Opportunities Scouting: Innovationschancen ausloten}, series = {Wissensmanagement - Das Magazin f{\"u}r F{\"u}hrungskr{\"a}fte}, volume = {12}, journal = {Wissensmanagement - Das Magazin f{\"u}r F{\"u}hrungskr{\"a}fte}, number = {4}, pages = {20 -- 22}, year = {2010}, abstract = {Bereits Joseph Alois Schumpeter - der von einem seiner Biografen auch der „Prophet of Innovation" genannt wird - nennt in seinem 1912 erschienenen Buch „Theorie der wirtschaftlichen Entwicklung", einem seiner Hauptwerke, neben der reinen Produktinnovation folgende weitere M{\"o}glichkeiten zur Innovation: neue Produktionsmethoden, neue Absatzm{\"a}rkte, neue Beschaffungsm{\"a}rkte und neue Organisationen.}, language = {de} } @article{Deckert2010, author = {Deckert, Carsten}, title = {Pick a Fight! Mit Streitlust zur Innovation}, series = {agora42}, volume = {2}, journal = {agora42}, number = {2}, pages = {40 -- 42}, year = {2010}, abstract = {Der {\"o}sterreichische Psychotherapeut Paul Watzlawick hat einmal in einem Interview gesagt, dass Menschen in beratenden Berufen - seien es nun Psychotherapeuten oder Unternehmensberater - in Bezug auf ihre Klienten vor einer paradoxen Anforderung st{\"u}nden. Die Anforderung lautet: "{\"A}ndere mich, ohne mich zu {\"a}ndern". Das heißt, der Klient w{\"u}rde zwar gerne sein Problem l{\"o}sen, aber nicht auf Kosten einer Ver{\"a}nderung des Status quo. Vor einer {\"a}hnlich paradoxen Anforderung stehen Innovatoren im Unternehmen. Die Anforderung, die dort gestellt wird, lautet: "Betreibe Innovation, ohne zu erneuern". Das bedeutet, dass Unternehmen sich gerne Innovationen w{\"u}nschen, aber wiederum nicht auf Kosten einer Ver{\"a}nderung des status quo.}, language = {de} } @inproceedings{Neef2013, author = {Neef, Matthias}, title = {Innerst{\"a}dtische Nutzung von Kleinwindkraftanlagen: Potentiale und H{\"u}rden}, series = {M{\"u}lheimer Initiative f{\"u}r Klimaschutz, 06.05.2013}, booktitle = {M{\"u}lheimer Initiative f{\"u}r Klimaschutz, 06.05.2013}, address = {M{\"u}lheim an der Ruhr}, organization = {M{\"u}lheimer Initiative f{\"u}r Klimaschutz e.V.}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-21017}, year = {2013}, language = {de} } @phdthesis{Neef2002, author = {Neef, Matthias}, title = {Analyse des Schlagfluges durch numerische Str{\"o}mungsberechnung}, volume = {ZLR-Forschungsbericht, 2}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:084-14501}, pages = {245}, year = {2002}, abstract = {Mit Hilfe eines Finite-Volumen-Verfahrens wird die dreidimensionale reibungsbehaftete Stroemung um einen schlagenden Fluegel berechnet. Die Bewegungsparamter sind dabei vergleichbar mit den Bedingungen im Reiseflug grosser Voegel. Das numerische Verfahren wird fuer den gezeigten Anwendungsfall, indem eine Methode zur Realisierung von beliebigen periodischen Bewegungen implemetiert wird. Eine Verifizierung erfolgt durch den Vergleich mit analytischen, numerischen und experimentellen Ergebnissen aus der Literatur. Mit dem verifizierten Verfahren werden die instationaeren Groessen wie Druck und Geschwindigkeiten in der Umgebung des bewegten Fluegels berechnet. Daraus ergeben sich ferner die zeitlich gemittelten Groessen wie Schub und Wirkungsgrad des Schlagfluges. Ausserdem wird die Interaktion von Laengs- und Querwirbeln im Nachlauf des schlagenden Fluegels untersucht. Es zeigt sich ein dominanter Einfluss der pulsierenden Randwirbel aufgrund der endlichen Spannweite, waehrend die Anfahr- und Stoppwirbel, verursacht durch die Fluegelbewegung, im Reiseflug grosser Voegel nahezu vernachlaessigbar erscheinen.}, language = {de} } @misc{OPUS4-1944, title = {676 - Vierte Satzung zur {\"A}nderung der Pr{\"u}fungsordnung f{\"u}r den Masterstudiengang Internationales Wirtschaftsingenieurwesen an der Hochschule D{\"u}sseldorf vom 28.08.2019}, address = {D{\"u}sseldorf}, organization = {Hochschule D{\"u}sseldorf}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-19446}, pages = {2}, year = {2019}, abstract = {Aufgrund der \S\S 2 Abs. 4, 64 Abs. 1 des Gesetzes {\"u}ber die Hochschulen des Landes Nordrhein-Westfalen (Hochschulgesetz - HG) vom 16.09.2014 (GV. NRW. S. 547) in der aktuell g{\"u}ltigen Fassung hat die Hochschule D{\"u}sseldorf die folgende Ordnung als Satzung erlassen.}, subject = {Pr{\"u}fungsrecht}, language = {de} } @inproceedings{HelmPugachevNeef2008, author = {Helm, Peter and Pugachev, Alexander and Neef, Matthias}, title = {Breaking the Swirl With Brush Seals: Numerical Modeling and Experimental Evidence}, series = {Proceedings of the ASME Turbo Expo 2008 : presented at the 2008 ASME Turbo Expo, June 9 - 13, 2008, Berlin, Germany}, volume = {4}, booktitle = {Proceedings of the ASME Turbo Expo 2008 : presented at the 2008 ASME Turbo Expo, June 9 - 13, 2008, Berlin, Germany}, publisher = {ASME}, address = {New York}, organization = {American Society of Mechanical Engineers Corporation; International Gas Turbine Institute Corporation}, isbn = {978-0-7918-4314-7}, doi = {10.1115/GT2008-50257}, pages = {1387 -- 1396}, year = {2008}, abstract = {Striving for smaller losses in turbomachinery has led to many advancements in the design of seals. Modern sealing concepts such as brush seals hold a great potential to increase the efficiency of both flight engines and stationary turbines. At the same time, in order to maintain stable operating conditions of the rotor, swirl-induced forces must be kept at a minimum in the sealing channels. Therefore, the influence of the permeable and flexible bristle pack of brush seals on the flow around the rotor surface must be known. In this paper the swirl flow in the cavities of two different seal geometries is studied experimentally and numerically. A conventional three-tooth labyrinth serves as a reference. A second seal arrangement with a bristle pack upstream of two teeth is compared with the reference labyrinth. The swirl is evaluated experimentally from total and static pressure measurements in various axial and circumferential positions. Additionally, the axial swirl distribution is calculated using computational fluid dynamics (CFD). Here, the numerical model of the brush seal is based on the porous medium approach and is calibrated using the experimental values of the leakage and the bristle clearance by adjusting the thickness of the bristle pack. The calibrated CFD model is then used to study the impact of the brush seal on the swirl component of the sealing flow. The observed significant decrease of the swirl by the brush seal shows good agreement with the experimental data. The impact of changes in bristle pack clearance on the swirl is also investigated and compared with experimental evidence. The aim is to show that the brush seals have a natural tendency to interrupt seal swirl. They can therefore be used for swirl control in order to create a beneficial impact on the dynamic stability of turbomachines.}, language = {en} } @inproceedings{NeefSuldaSuerkenetal.2006, author = {Neef, Matthias and Sulda, Erik and S{\"u}rken, Norbert and Walkenhorst, Jan}, title = {Design Features and Performance Details of Brush Seals for Turbine Applications}, series = {Proceedings of the ASME Turbo Expo 2006 : presented at the 2006 ASME Turbo Expo, May 6 - 11, 2006, Barcelona, Spain}, volume = {3}, booktitle = {Proceedings of the ASME Turbo Expo 2006 : presented at the 2006 ASME Turbo Expo, May 6 - 11, 2006, Barcelona, Spain}, publisher = {ASME}, address = {New York}, organization = {American Society of Mechanical Engineers Corporation; International Gas Turbine Institute Corporation}, isbn = {0-7918-4238-X}, doi = {10.1115/GT2006-90404}, pages = {1385 -- 1392}, year = {2006}, abstract = {Adaptive and contacting seals such as brush seals have been successfully applied to turbomachinery for several years. In large steam turbine applications, however, various challenges still persist. Special focus is directed at the long-term performance and longevity of brushes on conventional spring-backed seal segments in steam turbines. This issue is particularly related to wear during startup conditions. This paper discusses the results of wear tests, derived from simulated transient turbine behavior, where the resultant seal leakage under steady state conditions is monitored. It is shown that the brush seal is significantly capable of adapting to varying operating conditions, but exhibits a degree of performance degradation during the initial startups. Together with previously reported mid-term wear data and an experience based long-term phenomenological approach a general model for brush seal performance degradation is developed. This model can be used for performance prediction and exerts influence on brush seal design.}, language = {en} } @inproceedings{HurdTruckenmuellerThammetal.2005, author = {Hurd, Paul and Truckenmueller, Frank and Thamm, Norbert and Pollak, Helmut and Neef, Matthias and Deckers, Mathias}, title = {Modern Reaction HP/IP Turbine Technology Advances and Experiences}, series = {Proceedings of the ASME Power Conference - 2005 : includes papers from the 2005 International Conference on Power Engineering (ICOPE) ; presented at the 2005 ASME Power Conference, April 5 - 7, 2005, Chicago, Illinois, USA}, booktitle = {Proceedings of the ASME Power Conference - 2005 : includes papers from the 2005 International Conference on Power Engineering (ICOPE) ; presented at the 2005 ASME Power Conference, April 5 - 7, 2005, Chicago, Illinois, USA}, publisher = {ASME}, address = {New York}, isbn = {0-7918-4182-0}, doi = {10.1115/PWR2005-50085}, pages = {425 -- 435}, year = {2005}, language = {en} } @inproceedings{VoelkerCaseyNeefetal.2005, author = {V{\"o}lker, Lutz and Casey, Michael and Neef, Matthias and St{\"u}er, Heinrich}, title = {The Flow Field and Performance of a Model Low Pressure Steam Turbine}, series = {6th European Conference on Turbomachinery - Fluid Dynamics and Thermodynamics : conference proceedings; 7-11 March 2005, Lille, France}, booktitle = {6th European Conference on Turbomachinery - Fluid Dynamics and Thermodynamics : conference proceedings; 7-11 March 2005, Lille, France}, address = {Lille}, organization = {{\´E}cole Nationale Sup{\´e}rieure d'Arts et M{\´e}tiers}, year = {2005}, abstract = {A 3-stage model of a low pressure steam turbine has been equipped with extensive instrumentation to assess aerodynamic performance and for validation of numerical methods. Emphasis was placed on detailed measurements at the inlet and exit of the last stage guide vane. Two configurations were examined - the first used a guide vane with lean in the last stage and a the second used a guide vane combining both lean and sweep. The experimental results from the two configurations have been compared with data from various design methods, ranging from through-flow to 3D multistage viscous simulations with mixing planes. Despite the challenges in modelling complex rotating blades in a wet steam environment, good agreement between the numerical and experimental results was obtained, and the new stator vane combining lean and sweep achieved the desired increase in reaction at the hub section.}, language = {en} } @inproceedings{WindteRadespielNeef2005, author = {Windte, Jan and Radespiel, Rolf and Neef, Matthias}, title = {Aerodynamic Analysis of Flapping Airfoil Propulsion at Low Reynolds Numbers}, series = {MEGAFLOW - Numerical Flow Simulation for Aircraft Design}, volume = {NNFM, 89}, booktitle = {MEGAFLOW - Numerical Flow Simulation for Aircraft Design}, editor = {Kroll, Norbert and Fassbender, Jens K.}, publisher = {Springer-Verlag}, address = {Berlin, Heidelberg}, isbn = {978-3-540-24383-0}, doi = {10.1007/3-540-32382-1_21}, pages = {299 -- 313}, year = {2005}, language = {en} } @incollection{NeefHummel2002, author = {Neef, Matthias and Hummel, D.}, title = {Euler and Navier-Stokes Solutions for Flapping Wing Propulsion}, series = {High Performance Computing in Science and Engineering '01}, volume = {30}, booktitle = {High Performance Computing in Science and Engineering '01}, editor = {Krause, Egon and J{\"a}ger, Willi}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-642-62719-4}, doi = {10.1007/978-3-642-56034-7_37}, pages = {386 -- 395}, year = {2002}, language = {en} } @incollection{NeefHummel2001, author = {Neef, Matthias and Hummel, Dietrich}, title = {Euler Solutions for a Finite-Span Flapping Wing}, series = {Fixed and Flapping Wing Aerodynamics for Micro Air Vehicle Applications}, volume = {16}, booktitle = {Fixed and Flapping Wing Aerodynamics for Micro Air Vehicle Applications}, editor = {Mueller, Thomas J.}, publisher = {American Institute of Aeronautics and Astronautics}, address = {Reston, VA}, isbn = {978-1-56347-517-7}, doi = {10.2514/5.9781600866654.0429.0451}, pages = {429 -- 451}, year = {2001}, language = {en} } @article{NeefFritzenSchumacher2003, author = {Neef, Matthias and Fritzen, J. P. and Schumacher, G.}, title = {Evaluation of mount loads in dynamic testing of a jet engine}, series = {Mechanical Systems and Signal Processing}, volume = {17}, journal = {Mechanical Systems and Signal Processing}, number = {3}, publisher = {Elsevier}, doi = {10.1006/mssp.2001.1405}, pages = {665 -- 681}, year = {2003}, abstract = {In the dynamic testing of jet engines the evaluation of loads on the mount structure is vital for comparison with finite element calculations of such testing. Measuring these loads with the help of strain gauges applied to the structure becomes difficult if the mount is overdetermined and thus not every strain gauge can be assigned to a single load direction. In this study, the overdetermined mount structure of the BR715 engine was examined at one of the three mounting points between the Boeing 717 airframe and the engine, where loads in five directions were reacted. Firstly, the dependence of five measured strains upon known static load conditions at the mounting point had to be determined. For this purpose a static calibration test was carried out where defined forces and moments in known directions were applied to the structure while the output from five strain gauges was measured accordingly. The result was the desired relationship between loads and strains in terms of a matrix, which yields the corresponding load condition of the examined mounting point if multiplied with a set of strains. The same calibration procedure was carried out with a finite element model of the mount, where direct comparison to dynamic load results from the model itself was possible. With this model the validity of the above method was shown as well as possible errors which may occur while evaluating dynamic test results. The method was found to give satisfactory results even for dynamic loading, although some inertia forces disturb the signals in dynamic testing. Finally, the results from an actual dynamic engine test were processed into loads and then compared to the simulated loads from a finite element model of the engine. Good agreement was found and the indication of any remaining discrepancies was used to update the model for an even better representation of the dynamic test loads.}, language = {en} } @incollection{JonesCastroMahmoudetal.2002, author = {Jones, Kevin and Castro, Breno and Mahmoud, Osama and Pollard, S. and Platzer, Max and Neef, Matthias and Gonet, K. and Hummel, D.}, title = {A collaborative numerical and experimental investigation of flapping-wing propulsion}, series = {40th AIAA Aerospace Sciences Meeting \& Exhibit}, booktitle = {40th AIAA Aerospace Sciences Meeting \& Exhibit}, publisher = {American Institute of Aeronautics and Astronautics}, address = {Reston, Virigina}, doi = {10.2514/6.2002-706}, pages = {36}, year = {2002}, abstract = {An international, collaborative investigation is undertaken to evaluate the relative merits and limitations of various numerical methods and experimental measurement techniques, specifically for the analysis of flapping-wing propulsion. A finite aspect-ratio configuration is extensively investigated, both quantitatively and qualitatively, in a low-speed wind tunnel. Direct force measurements are made, as well as time-accurate and time-averaged laser Doppler velocimetry and unsteady flow visualization. The reduced frequency, mean angle of attack, aspect ratio and Reynolds number are varied in the experiments. The experiment is numerically simulated using flatplate theory, two and three-dimensional panel codes, and two and three-dimensional Euler and Navier- Stokes solvers. The ability of each of the methods to capture important aspects of the flow physics are evaluated through comparisons with each other and the experimental data. Additionally, the comparisons indicate areas where further research is needed. The collaborative effort provides a survey of available capabilities and provides a fixed set of flappingwing data for others to compare against.}, language = {en} } @article{DubberkeLinnemannAbbasetal.2018, author = {Dubberke, Frithjof H. and Linnemann, Matthias and Abbas, Wameedh Khider and Baumh{\"o}gger, Elmar and Priebe, Klaus-Peter and Roedder, Maximilian and Neef, Matthias and Vrabec, Jadran}, title = {Experimental setup of a cascaded two-stage organic Rankine cycle}, series = {Applied Thermal Engineering}, volume = {131}, journal = {Applied Thermal Engineering}, publisher = {Elsevier}, doi = {10.1016/j.applthermaleng.2017.11.137}, pages = {958 -- 964}, year = {2018}, abstract = {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.}, language = {en} } @article{FesekerKinellNeef2018, author = {Feseker, Daniel and Kinell, Mats and Neef, Matthias}, title = {Experimental Study on Pressure Losses in Circular Orifices With Inlet Cross Flow}, series = {Journal of Turbomachinery}, volume = {140}, journal = {Journal of Turbomachinery}, number = {7}, address = {ASME}, doi = {10.1115/1.4039842}, pages = {210}, year = {2018}, abstract = {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.}, language = {en} } @misc{FrankRoedderNeefetal.2018, author = {Frank, Lena and R{\"o}dder, Maximilian and Neef, Matthias and Adam, Mario}, title = {Heizung, L{\"u}ftung, Weiße Ware - Ein integriertes Systemkonzept f{\"u}r das Haus der Zukunft}, series = {KI K{\"a}lte Luft Klimatechnik}, volume = {54}, journal = {KI K{\"a}lte Luft Klimatechnik}, number = {11}, publisher = {H{\"u}thig}, issn = {1865-5432}, pages = {50 -- 56}, year = {2018}, abstract = {In energieeffizienten Geb{\"a}uden spielt der Bedarf an Energie f{\"u}r die Raumheizung gegen{\"u}ber der ben{\"o}tigten Energie f{\"u}r Warmwasser und zum Antrieb elektrischer Ger{\"a}te eine zusehends untergeordnete Rolle. Die thermische Energie f{\"u}r elektrische Haushalts­ger{\"a}te, wie Waschmaschine, K{\"u}hlschrank etc., wird f{\"u}r gew{\"o}hnlich dezentral im Ger{\"a}t erzeugt. Vor diesem Hintergrund ist das Ziel eines Forschungsprojekts der Bau und der Test eines Funktionsmusters zur funktionalen und energetischen Kopplung der Haushaltsger{\"a}te und der Heizungs- und L{\"u}ftungstechnik des Geb{\"a}udes. Grundgedanke dabei ist die Nutzung von Synergien bei Komponenten und W{\"a}rmestr{\"o}men, wie der W{\"a}rmepumpe als K{\"a}lteaggregat f{\"u}r den K{\"u}hlschrank, und die effiziente Nutzung von Abw{\"a}rme der Haushaltsger{\"a}te f{\"u}r die Warmwasserbereitung und Raumheizung.}, language = {de} } @article{BonkLauxRoedderetal.2017, author = {Bonk, Christian Dirk and Laux, Christoph and R{\"o}dder, Maximilian and Neef, Matthias}, title = {Design of a 1 KW Organic Rankine Cycle for Teaching and Research Issues}, series = {Energy Procedia}, volume = {129}, journal = {Energy Procedia}, publisher = {Elsevier}, doi = {10.1016/j.egypro.2017.09.117}, pages = {931 -- 938}, year = {2017}, abstract = {This paper deals with the design of a micro-scale ORC plant for teaching and research including the development of an automated control concept. The aim is to provide a safe and environmentally acceptable micro-scale heat engine, which can be developed, implemented and used in university labs for the education of students as well as for small research projects. The test rig allows the support of several learning outcomes on a multi-disciplinary level particularly for the implementation and simulation of small power systems. Special attention was given to the organic working fluid characteristics and its selection process. In addition to the above-mentioned performance goals, favourable safety properties and low global warming potential were decisive in the selection of the novel organic fluid called 3M™ Novec™ 649. The performance and the fluid behaviour of Novec 649 in a micro-scale power cycle are of major interest and the research goal for the test rig presented in this paper. Due to the expected power output of 1 kW, a scroll expander was chosen as the generator drive for the micro plant. In order to design the major parts of the ORC, the thermodynamic simulation software EBSILON®Professional was used. The supply temperature was set to 140 °C. As a result of the simulation, feasible expander inlet pressures spread from 5.5 bar to 8.5 bar. This leads to thermal efficiencies of the ORC in the order of 5 \%. Adding a recuperator to the cycle system decreases the operating pressure range but in the end, the thermal efficiency can be increased by 1.5 \%-points up to 6.2 \%. Finally, an automated control concept is introduced, where the pump is controlled via the fill level measurement system.}, language = {en} } @article{NeefZielkeFussenecker2017, author = {Neef, Matthias and Zielke, Thomas and Fussenecker, Claudia}, title = {„Engineering Conferences": Wissenschaftlich Kommunizieren im Master}, series = {Die Neue Hochschule}, volume = {58}, journal = {Die Neue Hochschule}, number = {3}, pages = {4}, year = {2017}, language = {de} } @article{RoedderNeefLauxetal.2016, author = {Roedder, Maximilian and Neef, Matthias and Laux, Christoph and Priebe, Klaus-P.}, title = {Systematic Fluid Selection for Organic Rankine Cycles and Performance Analysis for a Combined High and Low Temperature Cycle}, series = {Journal of Engineering for Gas Turbines and Power}, volume = {138}, journal = {Journal of Engineering for Gas Turbines and Power}, number = {031701}, publisher = {ASME}, doi = {10.1115/1.4031361}, pages = {168}, year = {2016}, abstract = {The organic Rankine cycle (ORC) is an established thermodynamic process that converts waste heat to electric energy. Due to the wide range of organic working fluids available the fluid selection adds an additional degree-of-freedom to the early design phase of an ORC process. Despite thermodynamic aspects such as the temperature level of the heat source, other technical, economic, and safety aspects have to be considered. For the fluid selection process in this paper, 22 criteria were identified in six main categories while distinguishing between elimination (EC) and tolerance criteria (TC). For an ORC design, the suggested method follows a practical engineering approach and can be used as a structured way to limit the number of interesting working fluids before starting a detailed performance analysis of the most promising candidates. For the first time, the selection process is applied to a two-stage reference cycle, which uses the waste heat of a large reciprocating engine for cogeneration power plants. It consists of a high temperature (HT) and a low temperature (LT) cycle in which the condensation heat of the HT cycle provides the heat input of the LT cycle. After the fluid selection process, the detailed thermodynamic cycle design is carried out with a thermodynamic design tool that also includes a database for organic working fluids. The investigated ORC cycle shows a net thermal efficiency of about 17.4\% in the HT cycle with toluene as the working fluid and 6.2\% in LT cycle with isobutane as the working fluid. The electric efficiency of the cogeneration plant increases from 40.4\% to 46.97\% with the both stages of the two-stage ORC in operation.}, language = {en} } @article{WolterZekornNeef2016, author = {Wolter, Nina and Zekorn, Thomas and Neef, Matthias}, title = {Station{\"a}re thermodynamische Prozesssimulationen am Beispiel eines Industriekraftwerks}, series = {BWK: das Energie-Fachmagazin}, volume = {68}, journal = {BWK: das Energie-Fachmagazin}, number = {6}, pages = {6 -- 10}, year = {2016}, abstract = {Um bauliche Ver{\"a}nderungen in bestehenden Kraftwerksprozessen auf ihre Wirkungsweise untersuchen und thermodynamisch beziehungsweise wirtschaftlich bewerten zu k{\"o}nnen, werden thermische Kraftwerksprozesse mit geeigneter Simulationssoftware abgebildet und in verschiedenen Detaillierungsstufen ausgelegt oder nachgerechnet. Im Folgenden wird ein Weg aufgezeigt, wie mit Hilfe einer station{\"a}ren Simulationssoftware die Gesamtjahresbilanz eines Kraftwerks vorausberechnet werden kann. Mit Hilfe von Prozessdaten aus Vorjahren wird nachgewiesen, dass das Berechnungsmodell das bestehende Kraftwerk mit einer Abweichung von weniger als drei Prozent bez{\"u}glich erzeugter elektrischer Leistung und Brennstoffeinsatz und bei bekannter Dampfproduktion abbilden kann. Das so verifizierte Modell kann zur Untersuchung von Zubaumaßnahmen oder Ver{\"a}nderungen im Kraftwerksprozess eingesetzt werden.}, language = {de} }