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Development and distribution of an in situ experimental wind turbine noise database
No full textInternational audienceThe PIBE project is the first French collaborative research project on wind turbine noise. One of its objectives is to quantify the experimental dispersion observed in situ on acoustic quantities/metrics and influencing parameters, and to compare it with the numerical dispersion estimated using acoustic propagation models. A long-term experimental campaign was carried out over consecutive 410 days around a wind farm comprising eight 80-metre-high and 90-metre diameter turbines. Acoustic sensors (five Class I sound level meters) were deployed on site, recording third-octave spectra and overall A- and Z-weighted values of the Leq indicator and fractile indices (L10, L50 and L90), at distances from 325 m to 1400 m from the wind turbines row. In addition, three 3D ultrasonic anemometers and a Lidar system were used to measure meteorological variables influencing long-range sound propagation (e.g. wind and temperature verical profiles). Besides, train and aircraft passing close to the site were inventoried to identify periods of high background noise. All experimental data have been processed into an ElasticSearch database. An interactive web application has been developed in R Shiny to facilitate processing, visualization and analysis of the experimental database
Predicting the impact of wind turbine noise: general overview and results of the PIBE project
No full textInternational audiencePIBE (Prévoir l’Impact du Bruit des Éoliennes – Predicting the impact of wind-turbine noise) is a research project funded by ANR (French National Research Agency) which main objectives are to better understand the noise levels created by wind-turbines and assess noise-reduction solutions. One topic of this project focuses on the propagation of uncertainty. Code_TYMPAN™ is an open-source software for calculating industrial noise in the environment. Its open architecture, implemented by a Python API, allows advanced users to build and solve models programmatically. This open architecture made possible the implementation of a parametrical computational tool (OCP – Outil de Calcul Paramétrique). This tool generates input data, launches the calculations with Code_TYMPAN™, generates and post-processes output data. Thus, sensitivity analysis and propagation of uncertainty were performed on an industrial test case. This development demonstrates the feasability of introducing uncertainties in acoustic engineering studies
Expérience d'une mise en oeuvre de méthode d'optimisation de programmes de maintenance initiaux sur la base des méthodes OMF et AP913
No full textInternational audienceWithin EDF, the current preventive maintenance programs applied to nuclear power plant equipment have been developed using two successive methods: an OMF method (RCM) [1] and a method based on the INPO AP913 process [2]. On a power plant starting up (EPR), a method of optimizing initial maintenance programs has been implemented, by mixing the two methods. During this exercise, an audit carried out by EDF R&D showed non-regression with current methods and was considered as input data for a simplified AP913 method described in this article [5]. This method was used to review maintenance templates for valves and ventilation equipment. It has provided encouraging results, particularly in terms of program reductions, clarification of the meaning of each maintenance task, and involving local maintenance personnel in optimizing maintenance programs. This optimized AP913 method will normally be implemented on a new power plant starting up. The detailed description of the different stages of the method initially implemented will make it possible to explain the links made between the two methods OMF/RCM and AP913 but also to consider the maintenance planning constraints described in AP928 [ 3]. Concrete examples will illustrate the method with a focus on the difficulties encountered at the time. Finally, an inventory of the current method after almost ten years will highlight the improvements of the method with a justification for these changes. In conclusion, the work on the initial method showed certain interest via an audit which underlined the non-regression and the resumption of the main principles in an optimized method. A cold analysis of the initial method with the identification of the difficulties encountered and the description of the current state of the method will make it possible to best prepare for the implementation of the optimized AP913 method on a new nuclear power plant.Au sein d'EDF, les programmes de maintenance préventive actuels appliqués aux équipements des centrales nucléaires ont été développés à l'aide de deux méthodes successives : une méthode OMF (RCM) [1] et une méthode basée sur le procédé INPO AP913 [2]. Sur une centrale en démarrage (EPR), il a été mis en place une méthode d'optimisation de programmes de maintenance initiaux, en mixant les deux méthodes. Lors de cet exercice, un audit réalisé par la R&D EDF a montré la non-régression avec les méthodes actuelles et a été prise en compte comme données d'entrée pour une méthode AP913 simplifiée décrite dans cet article [5]. Cette méthode a été utilisée pour revoir les volumes de maintenance des vannes et des équipements de ventilation. Elle a fourni des résultats encourageants, notamment en termes d'allégements de programme, de clarification du sens de chaque tâche de maintenance, et d'implication du personnel de maintenance local dans l'optimisation des programmes de maintenance. Cette méthode de l'AP913 optimisée va normalement être mise en oeuvre sur une nouvelle centrale en démarrage. La description en détail des différentes étapes de la méthode mise en oeuvre initialement va permettre d'expliciter les liens réalisés entre les deux méthodes OMF/RCM et AP913 mais aussi la prise en compte des contraintes de planification de la maintenance décrites dans l'AP928 [3]. Des exemples concrets vont illustrer la méthode avec un focus sur les difficultés rencontrées à l'époque. Enfin, un état des lieux de la méthode actuelle après près de dix ans soulignera les améliorations de la méthode avec une justification de ces changements. En conclusion, les travaux sur la méthode initiale ont montré un intérêt certain via un audit qui a souligné la nonrégression et la reprise des grands principes dans une méthode optimisée. Une analyse à froid de la méthode initiale avec l'identification des difficultés rencontrées et la description de l'état actuel de la méthode permettra de préparer au mieux la mise en oeuvre de la méthode AP913 optimisée sur une nouvelle centrale nucléaire
Analysis of Embedded Numerical Programs in the Presence of Numerical Filters
No full textInternational audienceThis chapter presents how Frama-C verifies some complex loop invariant for numerical embedded code and how to produce such invariants. Numerical embedded code usually defines an endless loop that takes inputs from sensors and that emits outputs for actuators. Moreover, such a code commonly uses some floating-point global memories to keep track of the input or output values from the previous loop cycles. These memories store a summary of previous values to filter the input or the output over time. Hence, recursive linear or Infinite Impulse Response (IIR) filters are very common in such code. Among such filters, low-pass filters are challenging for Frama-C since finding a loop invariant with complex relationships between the variables is never an evident task for the engineer. Hence, this chapter presents different approaches to find and organize inductive invariants for such numerical reactive systems and shows how Frama-C can prove them with its Eva and Wp plug-ins. It also exposes optimal theoretical results for first-order and higher-order filters to compare the quality of results of the different solutions. Several examples and several concrete solutions illustrate the generation/writing of such inductive invariants and their formal verification
Phasing out energy intensive homes. Reflecting on the spatio-temporal features of a market-based policy for the energy transition
No full textInternational audienceThis paper explores the spatio-temporal dynamics of market-based government in the housing sector in the context of energy transition policies. This sector has long been a place where regulations, labels, quality signs and various economic incentive initiatives have been implemented. This public policy took a new turn in 2021, with the introduction of measures aimed at gradually banishing from the rental market a specific category of housing: ‘energy sieves’, i.e. homes responsible for excessive energy consumption. This paper looks at how space and time have been taken into account in the design of this public policy, and how markets have reacted to this development
The Paris Low-Level Jet During Paname 2022 And Its Impact On The Summertime Urban Heat Island
No full textInternational audienceThe low-level jet (LLJ) and the urban heat island (UHI) are common nocturnal phenomena. While the UHI has been studied extensively, interactions of the LLJ and the urban atmosphere in general (and the UHI in particular) have received less attention. In the framework of the PANAME (PAris region urbaN Atmospheric observations and models for Multidisciplinary rEsearch) initiative in the Paris region, continuous profiles of horizontal wind speed and vertical velocity were recorded with two Doppler wind lidars (DWLs) – for the first time allowing for a detailed investigation of the summertime LLJ characteristics in the region. Jets are detected for 70 % of the examined nights, often simultaneously at an urban and a suburban site, highlighting the LLJ regional spatial extent. Emerging at around sunset, the mean LLJ duration is ∼ 10 h, the mean wind speed is 9 m s‑1, and the average core height is 400 m above the city. The temporal evolution of many events shows signatures that indicate that the inertial oscillation mechanism plays a role in the jet development: a clockwise veering of the wind direction and a rapid acceleration followed by a slower deceleration. The horizontal wind shear below the LLJ core induces variance in the vertical velocity (σw2) above the urban canopy layer. It is shown that σw2 is a powerful predictor for regional contrast in air temperature, as the UHI intensity decreases exponentially with increasing σw2 and strong UHI values only occur when σw2 is very weak. This study demonstrates how DWL observations in cities provide valuable insights into near-surface processes relevant to human and environmental health
Exploring carbon neutrality scenarios through the life cycle assessment lens: a review of literature and methodological challenges
No full textInternational audienceAbstract National carbon neutrality scenarios usually focus on territorial greenhouse gas (GHG) emissions. Their implementation could thus possibly result in some impact transfers to life cycle steps outside the territory or to other environmental issues. Life Cycle Assessment (LCA) could help to assess comprehensively these scenarios. In this perspective, this article provides a comprehensive review of the current state of the art regarding the combination of LCA and carbon neutrality. An analysis of the identified articles covers general characteristics and methods, including the definition of carbon neutrality, the functions and boundaries of LCA, the life cycle inventory, the impact assessment, and the choices of LCA modelling. The findings indicate an increasing interest in the environmental assessment of decarbonisation options, particularly in energy transition scenarios. However, carbon neutrality strategies extend beyond energy transformation alone. They require modifications in agriculture, industrial processes, and waste treatment, among other sectors. According to the evidence collected from this research, there are very few articles that incorporate LCA within a national carbon neutrality strategy, encompassing all GHG-emitting sectors. Valuable insights can be gleaned from the identified publications that evaluate complex systems with LCA, such as policies, scenarios, cities, and other macroscopic objects, relying on advanced LCA methodologies. Some challenges are still to be found, and future work will focus on the application of LCA to a specific national scenario aiming at reaching carbon neutrality on a territory for 2050
KEMASS : jumeau (numérique) multi-agent amélioré par les connaissances pour la prise en charge de la planification énergétique
No full textInternational audienceLa transition vers une distribution d’énergie dé- centralisée, où chaque nœud peut fonctionner à la fois comme consommateur et/ou producteur, présente de nombreux défis dans la conception et le test d’algorithmes de contrôle, notamment pour garantir la production. Le modèle actuel de planification énergétique, basé sur l’uniformité des nœuds, a du mal à capturer les dynamiques et les contraintes spécifiques des unités de production individuelles. Cet article présente KEMASS, une méthode et un processus pour générer un Système Multi-Agent à partir d’Ontologies et de Graphe de Connaissances décrivant le système, afin d’adapter les algorithmes d’optimisation des centrales électriques au nouveau contexte. Appliqué au cas d’une vallée de production d’énergie française, KEMASS simule de façon réaliste le système physique et optimise le calendrier de production d’énergie, tout en te- nant compte des contraintes locales. Bien qu’il ne s’agisse pas encore d’un jumeau numérique complet pour la génération de plans de production énergétique, KEMASS, grâce à ses graphes de connaissances et ontologies dynamiques, est plus adaptable à l’évolution vers un tel jumeau numérique que la plupart des méthodes de la littérature. L’utilisation de technologies de re- présentation des connaissances rend KEMASS ouvert à de nombreuses autres applications
