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Current research on aquifer thermal energy storage (ATES) in Germany
No full textInternational audienceZusammenfassung Die vorliegende Arbeit stellt die aktuelle Forschung in Deutschland zu thermischen Aquiferspeichern (ATES, engl.: aquifer thermal energy storage) und thermischen Bergwerksspeichern (MTES, engl.: mine thermal energy storage) vor. Es werden drei Forschungsstandorte zu Niedertemperatur-ATES (NT-ATES), acht zu Hochtemperatur-ATES (HT-ATES) sowie zwei zu MTES beschrieben. Trotz einer breit gefächerten Forschungslandschaft mit unterschiedlichen räumlichen Untersuchungsskalen, Forschungszielen und -methoden zeichnet sich der Großteil der Forschungsvorhaben durch einen niedrigen Technologie-Reifegrad (TRL, engl: technology readiness level) aus. Die große Anzahl an HT-ATES-Forschungsstandorten weist auf ein erhöhtes Forschungsinteresse im Vergleich zu LT-ATES hin. Einen aktuellen Forschungsschwerpunkt stellt insbesondere die ATES-Integration in Wärmenetze dar, wobei jedoch fast keines der Projekte konkret auf eine praktische Umsetzung abzielt. Im Rahmen künftiger Forschungsarbeiten sollten daher prioritär praxisnahe Demonstrationsanlagen errichtet sowie Schlüsselstandorte identifiziert werden. Abschließend wird in dieser Arbeit die Notwendigkeit optimierter regulatorischer Rahmenbedingungen diskutiert, welche Umweltrisiken adressieren sowie eine hohe Anlagenqualität und effiziente Genehmigungsverfahren sicherstellen.Abstract This paper reviews the current research on aquifer thermal energy storage (ATES) and mine thermal energy storage (MTES) in Germany providing descriptions of 3 low-temperature ATES (LT-ATES), 8 high-temperature ATES (HT-ATES), and 2 MTES research sites. While the overview reveals a diverse field of investigations spanning various spatial scales, research objectives, and methodologies, the predominant focus is limited to early-stage research with low technology readiness levels (TRL). The high number of HT-ATES research sites suggests greater research interest compared to LT-ATES. The integration of ATES into district heating (DH) grids in particular is a prominent research focus, yet almost none of the projects are specifically intended for practical implementation. Future research should therefore prioritize real-world demonstration projects and identify key locations, which is crucial for showcasing the benefits of ATES. The need for a streamlined regulatory framework that addresses environmental risks and ensures installation quality and efficient permit procedures is also discussed
Introduction
No full textInternational audienceÀ l’ère du numérique, la notion de vie privée rencontre de profondes transformations , de prolongements importants, en lien avec la numérisation toujours plus poussée de l’ensemble des sphères de nos vies. Trois inflexions majeures constituent un contexte nouveau reconfigurant les enjeux de protection de la vie privée et leur mise en œuvre ::•le développement de technologies démultipliant la production et l’usage de données personnelles et susceptibles de pénétrer l’intimité des individus qui reconfigurent le contrôle que chacun peut ou non exercer sur les informations le concernant ;•les exigences de mise en œuvre d’un nouveau cadre régulatoire à l’échelle européenne (RGPD, IA Act) qui se décline dans l’ensemble des organisations et institutions ;•l’émergence de prises de conscience et de mobilisations sociales autour de cet enjeu de la protection des libertés individuelles.Dans le secteur de l’énergie, cette question revêt une crucialité inédite en lien avec la numérisation des infrastructures énergétiques qui redessine les modalités de consommation et de production dans une période de transition énergétique. L’ouvrage présente de nombreux cas d’usages issus du monde de l’énergie pour cerner la manière dont ces problématiques s’agencent dans les différents espaces privés, publics et professionnels, afin d’étudier les questions de protection de la vie privée, par une approche pluridisciplinaire. Il intéressera universitaires, chercheurs du numérique et vie privée, professionnels du déploiement du RGPD et acteurs du monde de l’énergie
Conception et diffusion des technologies blockchain. Les épreuves de la protection de la vie privée
No full textInternational audiencePrésentées comme des technologies de confiance, les blockchains, enpermettant des échanges sécurisés de pair à pair sans l’intermédiaire d’untiers de confiance, immédiats et presque gratuits, possèdent un fort potentieldisruptif. Elles sont néanmoins controversées, notamment en matièrede vie privée. Ces questions de mise en conformité aux réglementationssont accentuées par l’émergence d’une préoccupation grandissante desusagers vis-à-vis de la protection de leur vie privée. À travers l’analysed’un cas d’usage, nous montrons quelles épreuves (gouvernance, gestiondes données personnelles, explicabilité) soulève cet antagonisme et quelscompromis sociotechniques (ont opérés les acteurs pour les dépasser). Sipour les concepteurs blockchain participant à la création de ce nouveauservice, ces compromis ont bridé le potentiel disruptif de la technologieils ont permis aux yeux des autres concepteurs l’émergence d’usages et debénéfices inattendus, comme celui de conforter le choix de la technologieblockchain comme une « solution de privacy ». Par ailleurs, la recherche desolutions permettant la mise en conformité est également passée par descompromis garantissant l’acceptabilité du service aux yeux des usagers,répondant aux enjeux plus larges de respect de la vie privée (respect del’intimité, garantie autour de l’autonomie et du contrôle des données)
Bayesian inference of numerical modeling-based morphodynamics: Application to a dam-break over a mobile bed experiment
No full textInternational audienceNumerical modeling of morphodynamics presents significant challenges in engineering due to uncertainties arising from inaccurate inputs, model errors, and limited computing resources. Accurate results are essential for optimizing strategies and reducing costs. This paper presents a step-by-step Bayesian methodology to conduct an uncertainty analysis of 2D numerical modeling-based morphodynamics, exemplified by a dam-break over a sand bed experiment. Initially, uncertainties from prior knowledge are propagated through the dynamical model using the Monte Carlo technique. This approach estimates the relative influence of each input parameter on results, identifying the most relevant parameters and observations for Bayesian inference and creating a numerical database for emulator construction. Given the computationally intensive simulations of Markov chain Monte Carlo (MCMC) sampling, a neural network emulator is used to approximate the complex 2D numerical model efficiently. Subsequently, a Bayesian framework is employed to characterize input parameter uncertainty variability and produce probability-based predictions
A Discontinuous Galerkin Method based on Compact Smoothness-Increasing-Accuracy-Conserving (SIAC) Reconstruction
No full textInternational audienceIn this paper, we introduce a new high-order Discontinuous Galerkin (DG) scheme based on a reconstruction method enhanced by Smoothness-Increasing-Accuracy-Conserving (SIAC) filters, named SR-DG (SIAC Reconstruction-DG), for the discretisation of convection and diffusion equations. The high-order filters are built in a compact multi-element framework to reconstruct the DG solution and its gradient at quadrature points and interfaces when assembling the residual using a convolution operation. This approach is investigated in order to improve both continuity in the inter-element regions which leads to a better behavior of the scheme for coarse mesh resolutions, while maintaining the global high-order accuracy of the DG scheme. The method not only meets the fixed objectives but also offers several additional and highly interesting advantages. These include the capability to reconstruct a unique state on each face, thereby eliminating the need for numerical fluxes. Added to that, a relaxation of the CFL constraints on the time step is observed for convection-diffusion problems. Furthermore, the method enables an accurate and efficient reconstruction of gradients through the derivative of the filter, offering a compelling alternative to existing diffusion schemes
Thermal stability and degradation of a low refractive index photo-crosslinkable adhesive
No full textInternational audienceIn some laser assemblies, optical components are glued on their metal mount using a photocrosslinkable adhesive. All these components are submitted to medium to high temperatures for several hours upon laser's operation time. The subsequent thermal stresses endured by the adhesive could lead to its degradation, alter thus the functioning of the assembly and impact the alignment of the laser, key issues in laser applications. This work focuses on the investigation and the modeling of the lifespan, the degradation in the face of thermal stresses, particularly those generated by a laser, and of the ageing of a photocrosslinkable adhesive, PC373HA. The thermal characterization is performed using ThermoGravimetric Analysis and allows for the development, the validation and the comparison of three models based on Arrhenius' law to estimate the lifetime of adhesives as a function of temperature. A temperature of 150°C is identified as a threshold to ensure limited degradation over the 15 hours requested for laser operation endurances. The Ozawa-Flynn-Wall model and the Kissinger-Akahira-Sunose model correctly reproduce PC373HA's thermal behavior submitted to different thermal scenarii (temperatures, heating rates…). Both show that the higher the temperature, the faster the degradation process, approximately 10 minutes at 220°C and 100 minutes at 180°C, much less than the required 15 hours. Besides, in the event of an incident with the laser, if the temperature exceeds 200°C for more than 10 minutes or 180°C for more than 100 minutes, corrective action should be taken, and the adhesive should be replaced. These models therefore provide fundamental information for laser applications and will allow the implementation of preventive solutions during use but also in case of incident
Low-temperature synthesis of mixed valence gold halide perovskites and exploration of their photoluminescence properties
No full textInternational audienceWe describe the structural and chemical properties of gold halide perovskites (Cs 2 Au I Au III X 6 , X = I, Br, Cl) synthesized at low temperatures. Photoluminescence shows bandgaps (1–1.4 eV), highlighting their potential for optoelectronic devices
Outcome of the VIKING project: status and perspectives of numerical modeling of flow-induced vibrations of nuclear power plant components
No full textInternational audienceCrucial nuclear power plant (NPP) components, such as fuel assemblies and steam generators, are exposed to flow-induced vibrations (FIV), potentially leading to fatigue problems and fretting wear of the material. Damage or failure of these components may lead to safety issues, thereby potentially necessitating unplanned outages of the reactor, resulting in substantial repair and standstill costs. With FIV being one of the leading causes of damage to these components, it is important to assess its impact on the integrity of fuel rods and steam generator tubes during the early design phase. While such an assessment has historically been done using semi-empirical models, due to the rise in computing power and capabilities, numerical tools are used more frequently, in particular in the last 10-15 years. To assess and further advance the current state-of-the-art of studying FIV in NPPs, the joint industry VIKING (Vibration ImpaKt In Nuclear power Generation) project was launched at the beginning of 2020. In this project, nine organizations collaborated for almost four years on FIV of configurations representative of steam generators and fuel rods and assemblies. This was done by performing numerical benchmark studies on five different experimental facilities. The current paper describes the main results and conclusions obtained from each numerical benchmark. Based on the individual findings, the status and perspectives of numerically simulating FIV of the aforementioned NPP components are presented
How to improve semantic interoperability? a concrete use case based on EUMED metering profile in the context of energy data space projects
No full textInternational audienceIn the context of information exchange between energy domains and across different sectors (such as Energy, Manufacturing, and Mobility) semantic interoperability between systems becomes an essential requirement. This paper addresses semantic interoperability lessons learned based on a concrete use case: Access to Metering and Customer Data. It leverages some results from Horizon Europe Energy Data Space projects, specifically OMEGA-X, EDDIE, Enershare, DataCellar and Int:Net
The influence of grain crushing and pore collapse on the formation of faults
No full textDuring an earthquake, slip occurs in a localised shear zone that features a heavily granulated fault core that can be characterised as a shear band. We study the formation of this fault core in a granular rock such as sandstone by developing a model of crushable granular media within the framework of Breakage Mechanics. This model accounts for the evolution of the grain size distribution, while also accounting for the co-evolution of the solid fraction. An enrichment with the Cosserat continuum allows for the model to predict finite-width shear bands. The model is then calibrated against experimental data taken from tests on Bentheim sandstone, and a parametric study of the mechanical parameters is conducted using linear stability analysis. We find that for deeply-buried rocks the shear bands have a compactive component, and the initial value of the solid fraction does not play a strong role in the initial band thickness, but can influence the rate of delocalisation of the band. Post-localisation behaviour is studied with the finite element method, which shows the formation of zones of dilation outside the band in addition to the compaction within the band. Using a modified Kozeny--Carman permeability law, it is shown that within the band the permeability reduces by several orders of magnitude, but can increase outside the band. Our results highlight the importance of modelling grain size and solid fraction evolution as they exert a controlling influence on hydromechanical properties that play an important role in fault formation and seismic slip.Document submitted to Journal of Geophysical Research: Solid Eart