Bidirectional Charging (Vehicle-to-Home) in Home Energy Management Systems: Exploring Potentials with a Simulation Tool

The home will become the most important link between heat, electricity and mobility. For instance, the concept of Vehicle-to-Home (V2H) allows to use the average long parking times of electric vehicles for energy management applications in the household. In this study, we focus on developing a simulation model in the Home Energy Management System (HEMS) to explore the impact of bidirectional charging on household energy supply. Bidirectional charging allows electric vehicles not only to take energy but also to feed energy back to supply other consumers. The study addresses the following research question: What is the potential for increasing self-sufficiency through bidirectional charging in a modern single-family house with HEMS assets? First of all, bidirectional charging was researched in initial pilot projects, and the findings were used to validate the results. Furthermore, load profiles for household loads, heat loads (heat pumps) and production profiles (photovoltaics) were collected. Based on the findings from the literature, a simulation model was developed that considers the dynamic interactions between the electric vehicle and the system components in the household. Different scenarios of bidirectional charging could be simulated and compared e.g. with a unidirectional system. In addition, different parameters could be adapted and analyzed through a sensitivity analysis. Parameters of photovoltaic power, orientation of the photovoltaic system, capacity of vehicle battery and home storage, as well as daily consumption by kilometers driven were varied. The results of the simulations show that bidirectional charging has the potential to increase the self-sufficiency of renewable energy (in this case photovoltaics) in the household, to reduce electricity costs and indirectly to reduce the load from the energy grid. It is important to say that the potential strongly depends on individual user behavior, photovoltaic power and the presence of the vehicle on site. This study contributes to the scientific literature by presenting a simulation model for bidirectional charging in HEMS. The results provide important insights for households and the simulation model can be a decision support tool for the choice and sizing of system components in the HEMS. In addition, the study provides input for further research and development in the field of electromobility and home energy management systems

Chapitre 4. Johann Joachim Christoph Bode : traducteur, imprimeur, Franc-Maçon

Johann Joachim Christoph Bode (1730-1793) nous emmène dans l’Allemagne du xviiie siècle. Traducteur déjà réputé de son temps, il fut un médiateur littéraire discret mais important de la littérature anglaise, et, à un degré beaucoup moindre, de la littérature française. Du français, il a traduit, à part quelques œuvres mineures, les Essais de Montaigne. Mais il lui revient en particulier le mérite d’avoir fait connaître les romans anglais de Fielding, Sterne, Smollett et Goldsmith aux Allemand..

Direct particle-fluid simulation of Kolmogorov-length-scale size particles in decaying isotropic turbulence

The modulation of decaying isotropic turbulence by 45 000 spherical particles of Kolmogorov-length-scale size is studied using direct particle–fluid simulations, i.e. the flow field over each particle is fully resolved by direct numerical simulations of the conservation equations. A Cartesian cut-cell method is used by which the exchange of momentum and energy at the fluid–particle interfaces is strictly conserved. It is shown that the particles absorb energy from the large scales of the carrier flow while the small-scale turbulent motion is determined by the inertial particle dynamics. Whereas the viscous dissipation rate of the bulk flow is attenuated, the particles locally increase the level of dissipation due to the intense strain rate generated near the particle surfaces due to the crossing-trajectory effect. Analogously, the rotational motion of the particles decouples from the local fluid vorticity and strain-rate field at increasing particle inertia. The high level of dissipation is partially compensated by the transfer of momentum to the fluid via forces acting at the particle surfaces. The spectral analysis of the kinetic energy budget is supported by the average flow pattern about the particles showing a nearly universal strain-rate distribution. An analytical expression for the instantaneous rate of viscous dissipation induced by each particle is derived and subsequently verified numerically. Using this equation, the local balance of fluid kinetic energy around a particle of arbitrary shape can be precisely determined. It follows that two-way coupled point-particle models implicitly account for the particle-induced dissipation rate via the momentum-coupling terms; however, they disregard the actual length scales of the interaction. Finally, an analysis of the small-scale flow topology shows that the strength of vortex stretching in the bulk flow is mitigated due to the presence of the particles. This effect is associated with the energy conversion at small wavenumbers and the reduced level of dissipation at intermediate wavenumbers. Consequently, it damps the spectral flux of energy to the small scales.</jats:p

Socio-Technical Analysis of Energy Demand Behaviour and Energy Consumption of Households Equipped with Smart Home Systems

German energy and climate policy pursues the goal of reducing greenhouse gas emissions in the long term. So that politics, industry and research institutes can find suitable strategies in this respect, information is needed on changes in the energy demand behaviour of final consumers. This paper analyses the energy consumption of 120 households equipped with smart home. It is examined whether statements about the participants and their environment can be made on the basis of the energy consumption (heat and electricity). In addition, the change in energy demand behaviour due to the use of smart home systems is analysed. For this purpose, the raw data of the field study will first be validated. Subsequently, procedures as well as methodologies, taking into account data sciences and analytics, are presented, which are used to visualize and analyse the energy consumption data. An outlook shows potentials for further studies in this field

Testing Applications for Home Energy Management in the Field

Poster Presentation at the DPES Research Day, (25-11-2022) Testing Applications for Home Energy Management in the Fiel

Datenerhebung und Analyse der Heizenergieeffizienz mit Smart Home Technologien

In der Heizperiode 2023/2024 wurden im Rahmen eines empirischen Anwendungstests 14 Mietwohnungen in einem Mehrfamilienhaus mit Smart Home Thermostaten ausgestattet. Die vorliegende Arbeit analysiert anhand der von den smarten Thermostaten erfassten Messdaten zu Temperatur-Niveaus, Soll-Ist-Vergleiche der Raumtemperaturen und die Heizleistung (Ventilöffnung) am Heizkörper. Durch statistische Auswertungen konnten Kennzahlen abgeleitet und das Heizverhalten der Haushalte bewertet werden. Neben den Daten der intelligenten Thermostate wurden auch die monatlichen Heizenergieverbräuche der einzelnen Wohnungen analysiert und kategorisiert, was ein Benchmarking der Verbräuche innerhalb des Gebäudes ermöglichte. Zukünftige Arbeiten werden die Korrelation weiterer Parameter des Heizverhaltens und -verbrauchs sowie die Untersuchung von Langzeiteffekten beinhalten. Übergeordnetes Ziel ist es, die Heizenergieeffizienz zu steigern, indem den Mietenden durch die Auswertung digitaler Daten ein Feedback zu ihrem Heizverhalten und -verbrauch gegeben wird