Vorarlberg University of Applied Sciences
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Assessing model predictive control for energy communities’ flexibilities
Get PDFRenewable energy communities (REC) are legal entities defined by the European Clean Energy Package to own and share energy resources. A common goal of RECs is to have a high self-consumption. This work focuses on how self-consumption can be increased by means of intelligent control of flexibilities based on a use case featuring a community battery energy storage (CBES). Many simulation studies for the control and optimization of distributed energy resources (DER) including community storage exist, focusing on various aspects, however, often neglecting important effects for a real implementation due to simplified assumptions: (A) The control or optimization routine is run open loop. Thereby, the influence of prediction and modeling errors is ignored, so that the results obtained represent only an upper limit for the effectiveness. (B) The availability of data is not considered appropriately which might render certain control approaches unpractical. In practice, this might be a limiting factor for forecasting methods and control methods in general. Especially, as RECs are of a distributed nature and the implementation of potentially costly data acquisition and information infrastructure could limit the economic rentability significantly. We investigate a realistic use case, constructed based on the current Austrian legal definition of RECs. Here, recent smart meter data of the REC participants, as it is made available by the distribution system operator (DSO) for settlement purposes. We utilize this data for control. Our realistic simulation model consists of several residential loads, a community PV system, two private PV systems and a CBES which is controlled to boost the RECs self-consumption. The model was implemented within the MOSAIK co-simulation framework. Due to the enforced modularity of this framework, the controller is integrated into the simulation model in a closed loop manner, addressing limitation (A) of similar studies. In addition, the data exchange between the different actors, such as the grid operator and the REC operator, is modeled, which clearly addresses limitation (B). A promising method for the control problem of the described REC is model predictive control (MPC) and its solution by means of mixed integer linear programming (MILP). To control the community storage system using MPC, an accurate prediction of the residual load is required. This forecast is created using a machine learning model (LSTM model), which is pre-trained on synthetic load profiles to improve the prediction with limited data availability. Results show that MPC can handle the model and prediction uncertainties generally well. Nevertheless, the consideration of forecasting and modelling uncertainties in the simulation shows that the achievable self-consumption rates can be significantly reduced. Utilizing simplified forecasting and considering modelling uncertainty reduces the self-consumption by up to 14.5% points in the use case considered. These losses can, however, be contained by accurate prediction methods. With the consideration of modelling uncertainties for the CBES model alone, we find that a discrepancy between real storage capacity and controller model capacity of 20% reduces the self-consumption by 3.9% points. As the CBES can be considered a comparably “easy to model” component, this highlights the need for closed loop simulation in the controller development for RECs
Entwicklung und Evaluation eines heuristischen Ladelastmanagement-Algorithmus für Elektro-Bus-Betriebshöfe in Vorarlberg
Get PDFDiese Masterarbeit umfasst die Entwicklung und Evaluation eines heuristischen Ladelastmanagement-Algorithmus für Elektrobusbetriebshöfe in Vorarlberg. Angesichts der zunehmenden Elektrifizierung von Busflotten führt ein fehlendes Lademanagement zu hohen Spitzenlasten, da aufgrund der Fahrpläne häufig ein gleichzeitiges Laden der Busse direkt bei Ankunft stattfindet. Der Algorithmus zielt darauf ab, die auftretende Spitzenleistung an den Ladeorten durch eine geeignete zeitliche Einplanung der Ladeintervalle zu reduzieren. Basierend auf dem Fahrplan entstehen Ladefenster mit spezifischem Energiebedarf. Durch eine definierte Ladeleistung der Busse ergibt sich die Länge eines Ladeintervalls, das innerhalb des Ladefensters eingeplant werden muss. Für alle möglichen Ladeintervalle wird die resultierende Spitzenleistung ermittelt. Falls mehrere gleichwertige Optionen bestehen, wird ein Ladeintervall gewählt, das die geringste Überschneidung mit anderen Ladeintervallen aufweist, um mehr Flexibilität für folgende Ladeintervalle zu gewährleisten. Dazu wird ein heuristischer Algorithmus aus der Literatur erweitert und an die Gegebenheiten in Vorarlberg angepasst, um die zeitliche Flexibilität der Ladeintervalle zu nutzen. Diese Erweiterungen ermöglichen die Betrachtung mehrerer Depots, einschließlich Zwischenladungen, unterschiedlicher Ladeleistungen und eines variablen Optimierungshorizonts über mehrere Tage. Da die zeitbasierte Berechnung der Leistungen für alle möglichen Ladeintervalle sehr rechenintensiv ist, wird eine Methode vorgestellt, die eine Auswahl einer kleineren Menge an Möglichkeiten erzeugt, um den Rechenaufwand zu verringern. Die Ergebnisse zeigen, dass auch bei den Gegebenheiten in Vorarlberg eine deutliche Reduktion der Spitzenleistungen erreicht wird, bei gleichzeitig sehr schneller Berechnung der Ergebnisse.This master's thesis involves the development and evaluation of a heuristic charging load management algorithm for electric bus depots in Vorarlberg. In view of the increasing electrification of bus fleets, a missing charging management leads to high peak loads, as buses are often charged simultaneously on arrival due to the timetables. The algorithm aims to reduce the peak power occurring at the charging locations by scheduling the charging intervals appropriately. Charging windows with specific energy demands are created based on the timetable. A defined charging power of the buses results in the length of a charging interval that must be scheduled within the charging window. The resulting peak power is determined for all possible charging intervals. If there are several equivalent options, a charging interval is selected that has the least overlap with other charging intervals in order to ensure more flexibility for subsequent charging intervals. For this purpose, a heuristic algorithm from the literature is extended and adapted to the conditions in Vorarlberg in order to utilize the temporal flexibility of the charging intervals. These extensions enable the consideration of several depots, including intermediate charging, different charging powers and a variable optimization horizon over several days. Since the time-based calculation of the power for all possible charging intervals is very computationally intensive, a method is presented that generates a selection of a smaller set of possibilities in order to reduce the computational effort. The results show that, even under the conditions in Vorarlberg, there is a significant reduction in peak power while the results are calculated very quickly
Push it smarter! A qualitative study on the experience design of push notifications of the language learning app Duolingo
Get PDFDie vorliegende Masterarbeit befasst sich mit dem Experience Design von Push-Benachrichtigungen, einem zentralen Bestandteil des App-Ökosystems. Die Smartphone-Nutzenden können ihre Push-Benachrichtigungen impulsiv oder aus einem bestimmten Grund deaktivieren, und dies kann auch bei den Sprachlern-Apps vorkommen. Ziel der Arbeit es, herauszufinden, welche Faktoren die Deaktivierung von Push-Benachrichtigungen in Sprachlern-Apps am stärksten beeinflussen. Anschließend soll eine Lösung gefunden werden, um die Nutzungserfahrung von Push-Benachrichtigungen in Sprachlern-Apps so umzugestalten, dass die Deaktivierung durch die Nutzenden minimiert wird. Im theoretischen Teil der Arbeit wird ein strukturierter Überblick über Studien zu Push-Benachrichtigungen gegeben. Besonderes Augenmerk liegt dabei auf der Beschreibung von Sprachlern-Apps und dem aktuellen Stand der Push-Benachrichtigungen in der App Duolingo. Push-Benachrichtigungen werden als integraler Bestandteil des Lernprozesses betrachtet, da ihre Deaktivierung die Nutzenden von einem wichtigen Kommunikationskanal abschneidet. Der Aspekt der Deaktivierung von Push-Benachrichtigungen wurde bisher nur in begrenztem Umfang untersucht, und die Maßnahmen, die dies verhindern könnten, wurden nicht diskutiert. Der empirische Teil besteht aus der von der Autorin durchgeführten Fallstudie und den prototypischen Lösungskonzepten. Ein zweiwöchiges Experiment mit N=10 Teilnehmenden, die die entwickelten Tagebuchprotokolle zur Selbstbeobachtung erhielten, wurde durchgeführt, gefolgt von Leitfadeninterviews. Die Studie ergab, dass die Hauptfaktoren für die Unzufriedenheit mit Push-Benachrichtigungen und zum Teil auch für die Deaktivierung dieser das fehlende optimale Timing, das Gefühl, sich ständig wiederholende Inhalte zu erhalten sowie oft der „passiv-aggressive“ Tone-of-Voice der Benachrichtigungstexte waren. Die Deaktivierung der Benachrichtigungen führte bei manchen Teilnehmenden dieser wissenschaftlichen Arbeit auch dazu, dass die Lernenden die App immer weniger nutzten, bis sie schließlich ganz aufhörten, ihre täglichen Aufgaben zu erledigen. Die Ergebnisse deuten auch darauf hin, dass ein höherer Grad an Personalisierung, sowohl in Bezug auf den Zeitpunkt als auch auf den Inhalt, einen direkten positiven Effekt auf die Einstellung gegenüber Push-Benachrichtigungen haben kann. Basierend darauf wurden Design-Personas erstellt, die die vier charakteristischen Typen von Nutzenden der Sprachlern-Apps repräsentieren. Unter Berücksichtigung dieser Personas wurden Prototypen für mögliche App-Verbesserungen im Zusammenhang mit Push-Benachrichtigungen erstellt. Diese Konzepte könnten in das bestehende App-Ökosystem integriert werden oder als Vorschläge für die Zukunft dienen.This master thesis deals with the experience design of push notifications, one of the essential components of the app ecosystem. Smartphone users may turn off their push notifications for specific reasons or on impulse whenever they interact with an app. The aim of the study is to identify the factors that mainly influence the deactivation of push notifications of language learning apps. It also attempts to find possible solutions on how to optimize the user experience of push notifications in language learning apps in order to minimise the deactivation of push notifications by users. The theoretical part of the thesis provides a structured overview of studies on push notifications. It also focuses on the current state of push notifications in language learning apps, especially the Duolingo app. The push notifications are seen as an integral part of the learning process, as turning them off disrupts an important communication channel. However, there has been limited research into the issue of users disabling push notifications, and no exploration into what might be done to mitigate this. The empirical part of the thesis includes the experiment conducted by the author and the prototypes of the design concepts. A two-week experiment was completed with 10 participants who were given self-observation diary protocols developed for this study. This was subsequently followed by guided interviews. The findings reveal that the main factors of frustration with push notifications, and in some cases for turning them off, were poor timing, the feeling that the content of the notifications was too repetitive, and the often “passive-aggressive“ tone of the notification texts. Disabling push notifications occasionally led learners to gradually use the app less and less, until they stopped doing their daily tasks altogether. The results also indicate that a higher level of personalisation, both in terms of timing and content, can have a direct positive effect on a user‘s attitude towards push notifications. On this basis, design personas were created representing four distinctive types of language learning app users. With these personas in mind, prototypes were created for possible app optimisations related to push notifications. These concepts could be integrated into the existing app ecosystem or be used as suggestions for the future
Laser-induced periodic surface structures and their application for gas sensing
No full textSemiconducting metal oxides are widely used for solar cells, photo-catalysis, bio-active materials and gas sensors. Besides the material properties of the semiconductor being used, the specific surface topology of the sensors determines device performance. This study presents different approaches for increasing the sensing area of semiconducting metal oxide gas sensors. Micro- and nanopatterned laser-induced periodic surface structures (LIPSSs) are generated on silicon, Si/SiO2 and glass substrates. The surface morphologies of the fabricated samples are examined by FE SEM. We selected the nanostructuring and characterization of nanostructured source Ni/Au and Ti/Au films prepared on glass using laser ablation as the most suitable of the investigated approaches. Surface structures produced on glass by backside ablation provide 100 nm features with a high surface area; they are also transparent and have high resistivity. The value of the hydrogen sensitivity in the range concentrations from 100 to 500 ppm was recorded using transmittance measurements to be twice as great for the nanostructured target TiO2/Au as compared to the NiO/Au. It was found that such transparent materials present additional possibilities for producing optical gas sensors
The benefit of a multi-wedge acoustic black hole at low-frequency mitigation
Get PDFIntroduction: Acoustic black holes (ABH) are capable to mitigate structural vibrations efficiently above a certain cut-on frequency. The most commonly used geometry for a flexible beam is a simple wedge following a power-law curve. A simple wedge demands large dimensions for achieving mitigation in the low-frequency range below 1000 Hz. It was shown recently by experiments and numerical simulation that a multi-wedge configuration is beneficial for realizing a compact design and still showing good performance at low frequencies.
Materials and Methods: The WKB approximation is extended for a single-wedge design. Expressions for the reflection coefficient and cut-on frequency are discussed for an arbitrary number of wedges—the suggested multi-wedge ABH.
Results: The main benefit of the stacked multi-wedge ABH is a great improvement in performance in the low-frequency range. A numerical example highlights the successful vibration mitigation. It is shown how a multi-wedge ABH is tuned towards low-frequency in terms of cut-on frequency and reflections’ coefficient. The improved performance of a multi-wedge ABH is benchmarked against the well-established simple ABH
Normative, policy, legal and organisational contexts shaping the responsiveness of social services to citizen participation
Get PDFThis report analyses the existing legal, policy and organisational frameworks in six EU countries (Austria, Denmark, France, Poland, Portugal, Romania) for incorporating the voices of citizens into the development and implementation of personal targeted social services. It focuses on four different types of social service: • Community-based disability services • Mental health services • Child protection services • Services for young people at risk of social exclusion. The analysis is part of the Horizon Europe research and innovation project ‘Increasing responsiveness to citizen voice in social services across Europe’ (RESPONSIVE) that runs from 2023-2026
Design of 16-channel, 100-GHz multimode polymer-based AWG
No full textWe present design of planar 16-channel, 100-GHz multi-mode polymer-based AWG. This AWG was designed for central wavelength of 1550 nm applying AWG-Parameters tool. The AWG structure was created and simulated in the commercial photonic tool PHASAR from Optiwave. Achieved transmission characteristics were evaluated by AWG-Analyzer tool. For the design, multi-mode waveguides having a cross-section of (4x4) µm2 were used. The simulated results show strong worsening of the transmission characteristics in comparison when using single-mode waveguides. Nevertheless, the transmitting channels are clearly separated. The reason for using thicker multi-mode waveguides in the design is possibility to fabricate the AWG structure on polymer basis using direct laser writing lithography