620 Ingenieurwissenschaften und Maschinenbau
Refine
Year of publication
- 2022 (7) (remove)
Document Type
- Article (4)
- Conference Proceeding (2)
- Report (1)
Has Fulltext
- yes (7)
Is part of the Bibliography
- no (7)
Keywords
- Computersicherheit (2)
- Ethernet (2)
- Ethernet-APL (2)
- Feldgeräte (2)
- Gießerei (2)
- IT Security (2)
- OT Security (2)
- Optimale Kontrolle (2)
- optimal scheduling (2)
- Ablaufplanung (1)
Techno-economic analysis that allocate costs to the energy flows of energy systems are helpful to understand the formation of costs within processes and to increase the cost efficiency. For the economic evaluation, the usefulness or quality of the energy is of great importance. In exergy-based methods, this is considered by allocating costs to the exergy instead of energy. As exergy represents the ability of performing work, it is often named the useful part of energy. In contrast, the anergy, the part of energy, which cannot perform work, is often assumed to be not useful.
However, heat flows as used e.g. in domestic heating are always a mixture of a relative small portion of exergy and a big portion of anergy. Although of lower quality, the anergy is obviously useful for these applications. The question is, whether it makes sense to differentiate between exergy and anergy and take both properties into account for the economic evaluation.
To answer this question, a new methodical concept based on the definition of an anergy-exergy cost ratio is compared to the commonly applied approaches of considering either energy or exergy as the basis for economic evaluation. These three different approaches for the economic analysis of thermal energy systems are applied to an exemplary heating system with thermal storages. It is shown that the results of the techno-economic analysis can be improved by giving anergy an economic value and that the proposed anergy-cost ratio allows a flexible adaptation of the evaluation depending on the economic constraints of a system.
We present a methodology based on mixed-integer nonlinear model predictive control for a real-time building energy management system in application to a single-family house with a combined heat and power (CHP) unit. The developed strategy successfully deals with the switching behavior of the system components as well as minimum admissible operating time constraints by use of a special switch-cost-aware rounding procedure. The quality of the presented solution is evaluated in comparison to the globally optimal dynamic programming method and conventional rule-based control strategy. Based on a real-world scenario, we show that our approach is more than real-time capable while maintaining high correspondence with the globally optimal solution. We achieve an average optimality gap of 2.5% compared to 20% for a conventional control approach, and are faster and more scalable than a dynamic programming approach.
We present a novel long short-term memory (LSTM) approach for time-series prediction of the sand demand which arises from preparing the sand moulds for the iron casting process of a foundry. With our approach, we contribute to qualify LSTM and its combination with feedback-corrected optimal scheduling for industrial processes.
The sand is produced in an energy intensive mixing process which is controlled by optimal scheduling. The optimal scheduling is solved for a fixed prediction horizon. One major influencing factor is the sand demand, which is highly disturbed, for example due to production interruptions. The causes of production interruptions are in general physically unknown. We assume that information about the future behavior of the sand demand is included in current and past process data. Therefore, we choose LSTM networks for predicting the time-series of the sand demand.
The sand demand prediction is performed by our multi model approach. This approach outperforms the currently used naive estimation, even when predicting far into the future. Our LSTM based prediction approach can forecast the sand demand with a conformity up to 38 % and a mean value accuracy of approximately 99%. Simulating the optimal scheduling with sand demand prediction leads to an improvement in energy savings of approximately 1.1% compared to the naive estimation. The application of our novel approach at the real production plant of a foundry proves the simulation results and verifies the capability of our approach.
This paper proposes an extended Petri net formalism as a suitable language for composing optimal scheduling problems of industrial production processes with real and binary decision variables. The proposed approach is modular and scalable, as the overall process dynamics and constraints can be collected by parsing of all atomic elements of the net graph. To conclude, we demonstrate the use of this framework for modeling the moulding sand preparation process of a real foundry plant.
Die Konvergenz von Netzwerken ist ein zunehmender Trend im Bereich der Automatisierung. Immer mehr Anlagenbetreiber streben eine Vereinheitlichung der Netzwerke in ihren Anlagen an. Dies führt zu einer nahtlosen Netzwerkstruktur, einer vereinfachten Überwachung und einem geringeren Schulungsaufwand für das Personal, da nur eine einheitliche Netzwerktechnologie gehandhabt werden muss. Ethernet-APL ist ein Teil des Puzzles für ein solches konvergentes Netzwerk und unterstützt verschiedene Echtzeitprotokolle wie PROFINET, EtherNet, HART-IP sowie das Middleware-Protokoll OPC UA. Dieses Papier gibt einen Überblick über die Auswirkungen von Ethernet-APL-Feldgeräten auf die OT-Sicherheit und schlägt vor, wie die OT-Sicherheit für diese Geräte gewährleistet werden kann.
In dieser Studie wurden Unternehmen, die Produktionsanlagen betreiben oder betreuen, zu ihrem Sicherheitsaufwand bei der Abfrage von Security Advisories für Automatisierungskomponenten befragt. Die befragten Unternehmen (vorwiegend KMU) machten Angaben zum zeitlichen, technischen und personellen Aufwand für die Auswertung von Security Advisories im Produktionsumfeld. Es wurde festgestellt, dass in vielen Unternehmen Defizite in Bezug auf diese Fragestellung bestehen. Dieses resultiert im Wesentlichen aus Mangel an Zeit und Mangel an qualifiziertem Personal. Eine in der Studie vorgeschlagene automatisierte Abfrage von Asset Inventories und eine automatisierte Zuordnung von Security Advisories zu den Assets wird von den befragten Unternehmen durchgehend als sinnvoll erachtet.
Network convergence is an increasing trend in the automation domain. More and more plant owners strive for a unification of networks in their plants. This yields a seamless network structure, simplified supervision, and reduced training effort for the personnel, as only one unified network technology needs to be handled. Ethernet-APL is one piece of the puzzle for such a converged network, supporting various real time protocols like PROFINET, EtherNet, HART-IP as well as the middleware protocol OPC UA. This paper gives an overview on the impact of Ethernet-APL field devices to OT security and proposes how to ensure OT security for them.