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Now showing items 41-50 of 141
Aufsatz
Design of Robust Total Site Heat Recovery Loops via Monte Carlo Simulation
(2019-03-10)
For increased total site heat integration, the optimal sizing and robust operation of a heat recovery loop (HRL) are prerequisites for economic efficiency. However, sizing based on one representative time series, not considering the variability of process streams due to their discontinuous operation, often leads to oversizing. The sensitive evaluation of the performance of an HRL by Monte Carlo (MC) simulation requires sufficient historical data and performance models. Stochastic time series are generated by distribution ...
Aufsatz
Rechtsverträgliche und qualitätszentrierte Gestaltung für "KI made in Germany"
(2020-02-21)
Künstlich intelligente (KI) Systeme erfreuen sich immer größerer Beliebtheit. Insbesondere smarte persönliche Assistenten (SPAs) von Amazon, Google und vielen weiteren verzeichnen ein stetiges Marktwachstum. Den vielfältigen Potenzialen dieser KI-Systeme stehen jedoch auch zahlreiche Risiken gegenüber. Berichte von Datenpannen und -lecks häufen sich und haben bei Nutzern eine zunehmende Skepsis zur Folge, was zu einem gespaltenen Bild von KI in der Gesellschaft beiträgt. Diesem Problem stellt sich das Forschungsprojekt ...
Aufsatz
Heat Pump Bridge Analysis using the Modified Energy Transfer Diagram
(2020-12-29)
Heat pumps are the key technology to decarbonise thermal processes by upgrading industrial surplus heat using renewable electricity. Existing insight-based integration methods refer to the idealised Grand Composite Curve requiring the full exploitation of heat recovery potential but leave the question of how to deal with technical or economic limitations unanswered. In this work, a novel Heat Pump Bridge Analysis (HPBA) is introduced for practically targeting technical and economic heat pump potential by applying ...
Aufsatz
Optimization of Process Parameters for Friction Stir Welding of Aluminum and Copper Using the Taguchi Method
(2019-01-10)
Producing joints of aluminum and copper by means of fusion welding is a challenging task. However, the results of various studies have proven the potential of friction stir welding (FSW) for manufacturing aluminum-copper joints. Despite the proven feasibility, there is currently no series application in automotive industry to produce aluminum-copper joints for electrical contacts by means of FSW. To make FSW as efficient as possible for large-scale production, maximized welding speed is desired. Taking this into ...
Aufsatz
Optimization of Cooling Utility System with Continuous Self-Learning Performance Models
(2019-05-20)
Prerequisite for an efficient cooling energy system is the knowledge and optimal combination of different operating conditions of individual compression and free cooling chillers. The performance of cooling systems depends on their part-load performance and their condensing temperature, which are often not continuously measured. Recorded energy data remain unused, and manufacturers’ data differ from the real performance. For this purpose, manufacturer and real data are combined and continuously adapted to form part-load ...
Aufsatz
Influence of Copper-Sided Tin Coating on the Weldability and Formation of Friction Stir Welded Aluminum-Copper-Joints
(2019-02-02)
Although the joining of aluminum and copper is a difficult task, several studies have shown that friction stir welding (FSW) is capable of producing aluminum-copper-joints with excellent performance. Therefore, it is desirable to use this joining technique for the production of cost- and weight-reduced conductors for the automotive sector. The exposed copper contact spots in automobiles are usually coated with tin for design reasons and in order to improve their corrosion resistance. In this context, it is possible ...
Aufsatz
Review of Steady-State Electric Power Distribution System Datasets
(2020-09-15)
Publicly available grid datasets with electric steady-state equivalent circuit models are crucial for the development and comparison of a variety of power system simulation tools and algorithms. Such algorithms are essential to analyze and improve the integration of distributed energy resources (DERs) in electrical power systems. Increased penetration of DERs, new technologies, and changing regulatory frameworks require the continuous development of the grid infrastructure. As a result, the number and versatility of ...
Aufsatz
Recent Developments in the Field of Modified Patankar-Runge-Kutta-methods
(2021-12-14)
Modified Patankar-Runge-Kutta (MPRK) schemes are numerical one-step methods for the solution of positive and conservative production-destruction systems (PDS). They adapt explicit Runge-Kutta schemes in a way to ensure positivity and conservation of the numerical approximation irrespective of the chosen time step size. Due to nonlinear relationships between the next and current iterate, the stability analysis for such schemes is lacking. In this work, we introduce a strategy to analyze the MPRK22(α)-schemes in the ...
Aufsatz
On a hybrid approximation concept for self-excited periodic oscillations of large-scale dynamical systems
(2021-12-14)
When approximating periodic solutions in the context of large-scale dynamical systems involving strong local nonlinearities, efficiency is of special interest. Hence, the literature suggests a combination of two approximation methods for increasing the ratio of computational cost to accuracy. Within this contribution, a combination of Finite Difference and Harmonic Balance method is proposed. Due to the usage of Harmonic Balance it is shown, that the resulting equations only depend on the degrees of freedom that are ...
Aufsatz
Using New Spare Parts for Repair of Waste Electrical and Electronic Equipment? The Material Footprint of Individual Components
(2022-02-21)
The growing production of waste electrical and electronic equipment (WEEE) requires close loop management to protect the environment and save resources. Repair and reuse can extend the product’s life span. However, debates on the differences seen in resource consumption linked to the different ways of repairing devices have received a limited amount of attention. This article demonstrates quantification of the resource consumption (cradle-to-gate) of five types of appliances on a component level based on life-cycle ...