Andrea Hohmann

Dr. Andrea Hohmann

orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 October 2020 in Applied Sciences
Verified
Journal Article
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MRMartin Roesch
Martin Roesch
CLChristian Linder
Christian Linder
RZRoland Zimmermann
Roland Zimmermann
ARAndreas Rudolf
Andreas Rudolf
AHAndrea Hohmann
Andrea Hohmann
GRGunther Reinhart
Gunther Reinhart
The growing share of renewable power generation leads to increasingly fluctuating and generally rising electricity prices. This is a challenge for industrial companies. However, electricity expenses can be reduced by adapting the energy demand of production processes to the volatile prices on the markets. This approach depicts the new paradigm of energy flexibility to reduce electricity costs. At the same time, using electricity self-generation further offers possibilities for decreasing energy costs. In addition, energy flexibility can be gradually increased by on-site power storage, e.g., stationary batteries. As a consequence, both the electricity demand of the manufacturing system and the supply side, including battery storage, self-generation, and the energy market, need to be controlled in a holistic manner, thus resulting in a smart grid solution for industrial sites. This coordination represents a complex optimization problem, which additionally is highly stochastic due to unforeseen events like machine breakdowns, changing prices, or changing energy availability. This paper presents an approach to controlling a complex system of production resources, battery storage, electricity self-supply, and short-term market trading using multi-agent reinforcement learning (MARL). The results of a case study demonstrate that the developed system can outperform the rule-based reactive control strategy (RCS) frequently used. Although the metaheuristic benchmark based on simulated annealing performs better, MARL enables faster reactions because of the significantly lower computation costs for its own execution.

19 December 2023 in Polymers
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Journal Article
Open access
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TPTobias Manuel Prenzel
Tobias Manuel Prenzel
AHAndrea Hohmann
Andrea Hohmann
TPTim Prescher
Tim Prescher
KAKerstin Angerer
Kerstin Angerer
DWDaniel Wehner
Daniel Wehner
Stefan AlbrechtStefan Albrecht
Stefan Albrecht
Carbon fibers (CFs) are a crucial material for lightweight structures with advanced mechanical performance. However, there is still a paucity of detailed understanding regarding the environmental impacts of production. Previously, mostly singled-out scenarios for CF production have been assessed, often based on scarce transparent inventory data. To expand the current knowledge and create a robust database for future evaluation, a life cycle assessment (LCA) was carried out. To this end, a detailed industry-approved LCI is published, which also proved plausible against the literature. Subsequently, based on a global scenario representing the market averages for precursor and CF production, the most relevant contributors to climate change (EF3.1 climate change, total) and the depletion of fossil energy carriers (EF3.1 resource use, fossil) were identified. The energy consumption in CF manufacturing was found to be responsible for 59% of the climate change and 48% of the fossil resource use. To enable a differentiated discussion of manufacturing locations and process energy consumption, 24 distinct scenarios were assessed. The findings demonstrate the significant dependence of the results on the scenarios’ boundary conditions: climate change ranges from 13.0 to 34.1 kg CO2 eq./kg CF and resource use from 262.3 to 497.9 MJ/kg CF. Through the investigated scenarios, the relevant reduction potentials were identified. The presented results help close an existing data gap for high-quality, regionalized, and technology-specific LCA results for the production of CF.

7 February 2023 in Sustainability
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Journal Article
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VKVincent Kalchschmid
Vincent Kalchschmid
VEVeronika Erhart
Veronika Erhart
KAKerstin Angerer
Kerstin Angerer
SRStefan Roth
Stefan Roth
AHAndrea Hohmann
Andrea Hohmann
Power-to-X processes where renewable energy is converted into storable liquids or gases are considered to be one of the key approaches for decarbonizing energy systems and compensating for the volatility involved in generating electricity from renewable sources. In this context, the production of “green” hydrogen and hydrogen-based derivatives is being discussed and tested as a possible solution for the energy-intensive industry sector in particular. Given the sharp, ongoing increases in electricity and gas prices and the need for sustainable energy supplies in production systems, non-energy-intensive companies should also be taken into account when considering possible utilization paths for hydrogen. This work focuses on the following three utilization paths: “hydrogen as an energy storage system that can be reconverted into electricity”, “hydrogen mobility” for company vehicles and “direct hydrogen use”. These three paths are developed, modeled, simulated, and subsequently evaluated in terms of economic and environmental viability. Different photovoltaic system configurations are set up for the tests with nominal power ratings ranging from 300 kWp to 1000 kWp. Each system is assigned an electrolyzer with a power output ranging between 200 kW and 700 kW and a fuel cell with a power output ranging between 5 kW and 75 kW. There are also additional variations in relation to the battery storage systems within these basic configurations. Furthermore, a reference variant without battery storage and hydrogen technologies is simulated for each photovoltaic system size. This means that there are ultimately 16 variants to be simulated for each utilization path. The results show that these utilization paths already constitute a reasonable alternative to fossil fuels in terms of costs in variants with a suitable energy system design. For the “hydrogen as an energy storage system” path, electricity production costs of between 43 and 79 ct/kWh can be achieved with the 750 kWp photovoltaic system. The “hydrogen mobility” is associated with costs of 12 to 15 ct/km, while the “direct hydrogen use” path resulted in costs of 8.2 €/kg. Environmental benefits are achieved in all three paths by replacing the German electricity mix with renewable energy sources produced on site or by substituting hydrogen for fossil fuels. The results confirm that using hydrogen as a storage medium in manufacturing companies could be economically and environmentally viable. These results also form the basis for further studies, e.g., on detailed operating strategies for hydrogen technologies in scenarios involving a combination of multiple utilization paths. The work also presents the simulation-based method developed in this project, which can be transferred to comparable applications in further studies.

30 January 2018 in Production Engineering
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Journal Article
Closed access
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AHAndrea Hohmann
Andrea Hohmann
Stefan AlbrechtStefan Albrecht
Stefan Albrecht
JLJan Paul Lindner
Jan Paul Lindner
BVBernhard Voringer
Bernhard Voringer
DWDaniel Wehner
Daniel Wehner
PLPhilip Leistner
Philip Leistner

28 July 2023 in Polymers
Verified
Journal Article
Open access
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MFMarion Früchtl
Marion Früchtl
ASAndreas Senz
Andreas Senz
SSSteffen Sydow
Steffen Sydow
JFJonas Benjamin Frank
Jonas Benjamin Frank
AHAndrea Hohmann
Andrea Hohmann
HCHenrik-Alexander Christ
Henrik-Alexander Christ
This research focuses on exploring the potential of mycelium as a sustainable alternative to wood or solid foam in pultruded glass fiber-reinforced plastic (GFRP) sandwich profiles. The study evaluates the performance and the environmental sustainability potential of this composite by mechanical tests and life cycle assessment (LCA). Analysis and comparison of pultruded sandwich profiles with mycelium, polyurethane (PUR) foam and chipboard demonstrate that mycelium is competitive in terms of its performance and environmental impact. The LCA indicates that 88% of greenhouse gas emissions are attributed to mycelium production, with the heat pressing (laboratory scale) being the main culprit. When pultruded profiles with mycelium cores of densities 350 and 550 kg/m³ are produced using an oil-heated lab press, a global warming potential (GWP) of 5.74 and 9.10 kg CO2-eq. per functional unit was calculated, respectively. When using an electrically heated press, the GWP decreases to 1.50 and 1.78 kg CO2-eq. Compared to PUR foam, a reduction of 23% in GWP is possible. In order to leverage this potential, the material performance and the reproducibility of the properties must be further increased. Additionally, an adjustment of the manufacturing process with in situ mycelium deactivation during pultrusion could further reduce the energy consumption.

1 January 2023 in Bauingenieur
Verified
Journal Article
Closed access
TNThomas Neuhäuser
Thomas Neuhäuser
LLLisa T. Lenz
Lisa T. Lenz
SSSimon F. Schäfer
Simon F. Schäfer
AHAndrea Hohmann
Andrea Hohmann
RDRüdiger Daub
Rüdiger Daub
In 72 % der Fabrikplanungsprojekte werden die Kostenziele verfehlt und die Zeitziele in 60 %. Dies ist vor allem auf eine mangelhafte Kommunikation und Koordination zwischen den Planungsbeteiligten zurückzuführen. Um diesen Herausforderungen zu begegnen, werden zunehmend neue Methoden und Werkzeuge in der Fabrikplanung eingesetzt. Eine solche Methode ist das Building Information Modeling (BIM) aus der Bauwirtschaft. Ein Element von BIM stellt das Level of Coordination (LOC) dar, welches die phasenbezogene Ausprägung der geometrischen Kollisionsprüfungen und alphanumerischen Qualitätsprüfungen abbildet. Dieses wurde in einem ersten Beitrag (Teil 1: Level of Coordination in der Fabrikplanung) konzeptionell entworfen und auf die Fabrikplanung übertragen. Der vorliegende Beitrag stellt Teil 2 dar, in welchem das Konzept zunächst nochmals erläutert wird und auf ein reales, repräsentatives Projekt angewendet wird. Die anschließende Bewertung zeigt, dass die Nutzung des LOC zu einer Erhöhung der Kosten- und Terminsicherheit in Fabrikplanungsprojekten führen kann.