@article{VennemannSpaete2019, author = {Vennemann, Peter and Sp{\"a}te, Frank}, title = {Alle Jahre wieder - die Lehre im Fokus}, series = {Sonnenenergie}, volume = {2019}, journal = {Sonnenenergie}, number = {2}, editor = {Pr{\"a}sidium der Deutschen Gesellschaft f{\"u}r Sonnenenergie (DGS),}, issn = {0172-3278}, pages = {88 -- 89}, year = {2019}, language = {de} } @inproceedings{BuddeKlemmTocklothetal.2023, author = {Budde, Janik and Klemm, Christian and Tockloth, Jan N. and Becker, Gregor and Vennemann, Peter}, title = {Automatisierte Modellierung und Optimierung urbaner Energiesysteme}, series = {6. Regenerative Energietechnik Konferenz in Nordhausen 09. - 10. Februar 2023}, booktitle = {6. Regenerative Energietechnik Konferenz in Nordhausen 09. - 10. Februar 2023}, isbn = {978-3-940820-21-1}, pages = {150 -- 159}, year = {2023}, abstract = {Traditionelle, lineare Energiesysteme werden zunehmend zu vernetzten, regenerativen Energiesystemen transformiert. Mit dem auf dem „Open Energy Modelling Framework" (oemof) basierenden „Spreadsheet Energy System Model Generator" (SESMG) wurde ein Tool entwickelt, welches die Komplexit{\"a}t und Wechselwirkungen moderner Energiesysteme auf urbaner Ebene automatisiert abbildet. Zur Erstellung individueller Energiesystemmodelle sind ausschließlich quartiersspezifische Parameter notwendig, technische und wirtschaftliche Parameter sind standardm{\"a}ßig hinterlegt. Mit Hilfe von Algorithmen werden Energieversorgungsszenarien identifiziert, welche individuell definierte Zielgr{\"o}ßen (z. B. monet{\"a}re Kosten oder Treibhausgasemissionen) minimieren. Durch die implementierten Methoden zur Modellvereinfachungen k{\"o}nnen auch mit begrenzten Rechenressourcen (insb. Rechenzeit und Arbeitsspeicherbedarf) große Systeme modelliert und optimiert werden. Die Zielszenarien werden als Diagramme und f{\"u}r die Weiterverarbeitung mit Geoinformationssystemen aufbereitet, sodass die Ergebnisse analysiert, plausibilisiert und pr{\"a}sentiert werden k{\"o}nnen.}, language = {de} } @inproceedings{JacobsMesenhoellerJakirlicetal.2023, author = {Jacobs, Steffen and Mesenh{\"o}ller, Eva and Jakirlic, Suad and Vennemann, Peter}, title = {Computational Study of Transient Indoor Airflow with Reference to a Complementary Experiment}, series = {Proceedings of the Tenth International Symposium On Turbulence, Heat and Mass Transfer. K. Hanjalic, D. Borello, K. Suga, P. Venturini (Eds.)}, booktitle = {Proceedings of the Tenth International Symposium On Turbulence, Heat and Mass Transfer. K. Hanjalic, D. Borello, K. Suga, P. Venturini (Eds.)}, editor = {Hanjalic, K. and Borello, D. and Suga, K. and Venturini, P.}, publisher = {Begell House Inc.}, address = {New York, Wallingford}, organization = {ICHMT}, isbn = {978-1-56700-534-9}, issn = {2377-2816}, pages = {681 -- 684}, year = {2023}, abstract = {A novel approach for ventilation systems is a periodically varying supply air flow rate, the so-called unsteady mode of operation. So far, useful effects of this unsteady operating mode have been observed, but the effect mechanisms are still unknown. In this manuscript, simulations using the recently proposed k-ω-ζ - f model implemented in a sensitized RANS computational framework for a cuboid room with swirl diffusers are compared and validated with PIV measurements.}, language = {en} } @inproceedings{TocklothKlemmBeckeretal.2024, author = {Tockloth, Jan N. and Klemm, Christian and Becker, Gregor and Blankenstein, Benjamin and Vennemann, Peter}, title = {Der Spreadsheet Energy System Model Generator (SESMG): Ein Tool zur Optimierung urbaner Energiesysteme}, series = {16. Steinfurter Bioenergiefachtagung - Tagungsband}, booktitle = {16. Steinfurter Bioenergiefachtagung - Tagungsband}, pages = {18 -- 19}, year = {2024}, abstract = {Der Spreadsheet Energy System Model Generator (SESMG) ist ein Werkzeug zur Modellierung und Optimierung von (urbanen) Energiesystemen. Der SESMG hat eine browserbasierte grafische Benutzeroberfl{\"a}che, eine tabellenbasierte Dateneingabe und eine ausf{\"u}hrliche Dokumentation, was einen einfachen Einstieg erm{\"o}glicht. Zudem erfordern die Installation und Anwendung keine Programmierkenntnisse. Im SESMG sind verschiedene Modellierungsmethoden implementiert, wie z. B. die Anwendung des Multi-Energie-System-Ansatzes, die multikriteriale Optimierung, modellbasierte Methoden zur Reduktion des Rechenaufwands sowie die automatisierte Erstellung von r{\"a}umlich hoch aufgel{\"o}sten Energiesystemmodellen. Somit k{\"o}nnen urbane Energiesysteme mithilfe des SESMGs mit vergleichsweise geringem Aufwand, aber unter Ber{\"u}cksichtigung einer Vielzahl von Parametern und Randbedingungen, modelliert und optimiert werden.}, language = {de} } @article{WetterJantzenVennemann2014, author = {Wetter, Christof and Jantzen, H.-A. and Vennemann, Peter}, title = {Institut f{\"u}r Energie und Prozesstechnik (IEP) b{\"u}ndelt Fachwissen}, series = {gwi gasw{\"a}rme international}, journal = {gwi gasw{\"a}rme international}, number = {06/2014}, pages = {85 -- 87}, year = {2014}, language = {de} } @article{QuestArendtKlemmetal.2022, author = {Quest, Gemina and Arendt, Rosalie and Klemm, Christian and Bach, Vanessa and Budde, Janik and Vennemann, Peter and Finkbeiner, Matthias}, title = {Integrated Life Cycle Assessment (LCA) of Power and Heat Supply for a Neighborhood: A Case Study of Herne, Germany}, series = {energies}, volume = {15}, journal = {energies}, number = {16}, issn = {1996-1073}, doi = {10.3390/en15165900}, pages = {5900}, year = {2022}, abstract = {(1) The use of renewable energy for power and heat supply is one of the strategies to reduce greenhouse gas emissions. As only 14\% of German households are supplied with renewable energy, a shift is necessary. This shift should be realized with the lowest possible environmental impact. This paper assesses the environmental impacts of changes in energy generation and distribution, by integrating the life cycle assessment (LCA) method into energy system models (ESM). (2) The integrated LCA is applied to a case study of the German neighborhood of Herne, (i) to optimize the energy supply, considering different technologies, and (ii) to determine the environmental impacts of the base case (status quo), a cost-optimized scenario, and a CO2-optimized scenario. (3) The use of gas boilers in the base case is substituted with CHPs, surface water heat pumps and PV-systems in the CO2-optimized scenario, and five ground-coupled heat pumps and PV-systems for the cost-optimized scenario. This technology shift led to a reduction in greenhouse gas emissions of almost 40\% in the cost-optimized, and more than 50\% in the CO2-optimized, scenario. However, technology shifts, e.g., due to oversized battery storage, risk higher impacts in other categories, such as terrestrial eco toxicity, by around 22\%. Thus, it can be recommended to use smaller battery storage systems. (4) By combining ESM and LCA, additional environmental impacts beyond GHG emissions can be quantified, and therefore trade-offs between environmental impacts can be identified. Furthermore, only applying ESM leads to an underestimation of greenhouse gas emissions of around 10\%. However, combining ESM and LCA required significant effort and is not yet possible using an integrated software.}, language = {en} } @inproceedings{MesenhoellerVennemannHussong2021, author = {Mesenh{\"o}ller, Eva and Vennemann, Peter and Hussong, Jeanette}, title = {Investigation of Unsteady Room Ventilation with Particle Image Velocimetry (PIV)}, series = {15th RoomVent Virtual Conference February 15th - 17th, 2021}, booktitle = {15th RoomVent Virtual Conference February 15th - 17th, 2021}, address = {Turin, Italien}, isbn = {9788894612301}, pages = {387 -- 390}, year = {2021}, abstract = {The effects of different unsteady ventilation strategies on flow-structures in a room are investigated and compared to steady ventilation with the same mean exchange rate. For this, whole-field optical flow measurements were executed by means of a particle image velocimetry system (PIV) in a Reynolds-scaled room model in water. In a first series of experiments, sinusoidal varied supply flows with different frequencies were analysed; two equally supplied simple nozzles in the ceiling were used as inlets. The setup was validated by comparing jet velocities with literature values. Typically, room airflows are investigated with punctual measurement techniques (e.g. anemometers), which have an impact on the flow field, or with smoke gas experiments. By using PIV, the flow can be analysed without any influence of sensors or stands/traverses and whole-field measurement data with high spatial resolution and detailed information on the flow field can be collected. Local and time-averaged velocities and standard deviations were calculated for all scenarios. Unsteady conditions were created by a sinusoidal variation of the supply flow rate with frequencies between 0.025 1/s and 0.050 1/s, an offset of about 1.1 m3/h and an amplitude of about ±1.0 m3/h, which leads to a mean exchange rate of 3.5 1/h. Although averaged velocity fields only show slight differences between steady and unsteady conditions, single pictures vary widely. First effects of unsteady ventilation on flow structures can be recognized. Steady structures are destroyed, and velocities change rapidly. The inlets will be changed to small-scale ceiling-diffusors in future experiments to create more realistic room ventilation conditions. Other types of unsteady supply flows will be implemented, and parameters will be varied. The results of the PIV-measurements can be used to validate CFD simulations and to derive dimensioning rules and application recommendations.}, language = {en} } @techreport{HoernschemeyerSoefkerRienietsNiestenetal.2023, author = {H{\"o}rnschemeyer, Birgitta and S{\"o}fker-Rieniets, Anne and Niesten, Jan and Arendt, Rosalie and Kleckers, Jonas and Stretz, Celestin and Klemm, Christian and Budde, Janik and Wagner, R{\"u}diger and Vonhoegen, Laura and Reicher, Christa and Grimsehl-Schmitz, Winona and Wirbals, Daniel and Stieglitz-Broll, Eva-Maria and Agatz, Kerstin and Bach, Vanessa and Finkbeiner, Matthias and Lewe, Mareike and Henrichs, Malte and Haberkamp, Jens and Walter, Gotthard and Flamme, Sabine and Vennemann, Peter and Zamzow, Malte and Seis, Wolfgang and Matzinger, Andreas and Sonnenberg, Hauke and Rouault, Pascale and Maßmann, Stefanie and Fuchs, Lothar and Plogmeier, Christoph and Steinkamp, Arne and Şereflioğlu, Şenay and M{\"u}ller, Claus and Spital, Matthias and Uhl, Mathias}, title = {Leitfaden RessourcenPlan - Teil 1: Konzeption RessourcenPlan. Ergebnisse des Projekts R2Q RessourcenPlan im Quartier}, publisher = {FH M{\"u}nster}, address = {M{\"u}nster}, organization = {IWARU Institut f{\"u}r Infrastruktur·Wasser·Ressourcen·Umwelt}, doi = {10.25974/fhms-15746}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-157463}, year = {2023}, language = {de} } @techreport{KlemmBuddeBeckeretal.2023, author = {Klemm, Christian and Budde, Janik and Becker, Gregor and Arendt, Rosalie and Bach, Vanessa and Finkbeiner, Matthias and Vennemann, Peter}, title = {Leitfaden RessourcenPlan - Teil 2.4: Ressourcenmanagement Energie. Ergebnisse des Projekts R2Q RessourcenPlan im Quartier}, doi = {10.25974/fhms-15756}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-157560}, year = {2023}, language = {de} } @article{KlemmWieseVennemann2023, author = {Klemm, Christian and Wiese, Frauke and Vennemann, Peter}, title = {Model-based run-time and memory reduction for a mixed-use multi-energy system model with high spatial resolution}, series = {Applied Energy}, volume = {334}, journal = {Applied Energy}, issn = {0306-2619}, doi = {10.1016/j.apenergy.2022.120574}, pages = {120574}, year = {2023}, abstract = {Local and regional energy systems are becoming increasingly entangled. Therefore, models for optimizing these energy systems are becoming more and more complex and the required computing resources (run-time and random access memory usage) are increasing rapidly. The computational requirements can basically be reduced solver-based (mathematical optimization of the solving process) or model-based (simplification of the real-world problem in the model). This paper deals with identifying how the required computational requirements for solving optimization models of multi-energy systems with high spatial resolution change with increasing model complexity and which model-based approaches enable to reduce the requirements with the lowest possible model deviations. A total of 12 temporal model reductions (reduction of the number of modeled time steps), nine techno-spatial model reductions (reduction of possible solutions), and five combined reduction schemes were theoretically analyzed and practically applied to a test case. The improvement in reducing the usage of computational resources and the impact on the quality of the results were quantified by comparing the results with a non-simplified reference case. The results show, that the run-time to solve a model increases quadratically and memory usage increases linearly with increasing model complexity. The application of various model adaption methods have enabled a reduction of the run-time by over 99\% and the memory usage by up to 88\%. At the same time, however, some of the methods led to significant deviations of the model results. Other methods require a profound prior knowledge and understanding of the investigated energy systems to be applied. In order to reduce the run-time and memory requirements for investment optimization, while maintaining good quality results, we recommend the application of (1) a pre-model that is used to (1a) perform technological pre-selection and (1b) define reasonable technological boundaries, (2) spatial sub-modeling along network nodes, and 3) temporal simplification by only modeling every nth day (temporal slicing), where at least 20\% of the original time steps are modeled. Further simplifications such as spatial clustering or larger temporal simplification can further reduce the computational effort, but also result in significant model deviations.}, language = {en} }