Papers by Jean-jacques Roux
HAL (Le Centre pour la Communication Scientifique Directe), 2018
RESUME. La modélisation de la demande énergétique des bâtiments à l'échelle de la ville permet d'... more RESUME. La modélisation de la demande énergétique des bâtiments à l'échelle de la ville permet d'évaluer les stratégies de maîtrise des consommations énergétiques. A cette échelle, le manque de données détaillées et le coût numérique nécessitent de faire des hypothèses et de simplifier les modèles, ce qui rend la modélisation incertaine. Cependant l'impact des choix de modélisation sur la courbe de charge n'est pratiquement jamais analysé. De telles analyses sont menées en confrontant deux outils de modélisation et en étudiant spécifiquement l'impact de certaines simplifications courantes. Il est ainsi mis en évidence que la prise en compte des espaces non chauffés est cruciale pour une bonne modélisation des surfaces déperditives et que les simplifications courantes ont relativement peu d'impact sur le besoin annuel mais qu'elles peuvent causer des déformations de la courbe de charge localement importante. MOTS-CLÉS : modélisation énergétique quartier bottom-up, analyse de sensibilité, courbe de charge. ABSTRACT. Building energy models at city scale aim to evaluate energy management strategies. At this scale, the lack of detailed data and the computational cost imply to make some assumptions and to simplify the models, leading to uncertain modelling. However, the impact of the modelling choices on the load curve are nearly never analysed. Such analysis are carried on based on tools comparison and on some usual simplifications studies. It is highlighted that it is crucial to model un-heated spaces for a good estimation of the heat loss area, and that the impact of the usual simplifications on the annual energy needs is low but can be locally high for the load curve.
Renewable & Sustainable Energy Reviews, 2018
Many computational approaches exist to estimate heating and cooling energy demand of buildings at... more Many computational approaches exist to estimate heating and cooling energy demand of buildings at city scale, but few existing models can explicitly consider every buildings of an urban area, and even less can address hourly-or less-energy demand. However, both aspects are critical for urban energy supply designers. Therefore, this paper gives an overview of city energy simulation models from the point of view of short energy dynamics, and reviews the related modeling techniques, which generally involve detailed approaches. Analysis highlights computational costs of such simulations as key issue to overcome towards reliable microsimulation of the power demand of urban areas. Relevant physical and mathematical simplifications as well as efficient numerical and computational techniques based on uncertainties analysis and error quantification should thus be implemented.
The heat transfer characteristics in building window frame have significant three-dimensional cha... more The heat transfer characteristics in building window frame have significant three-dimensional characteristics, but window U-value model are often used in most building codes for thermal analyses to simplify the calculations. State model reduction techniques were used to develop loworder three-dimensional heat transfer model for window frame, which is efficient and accuracy. The method was validated for a envelope designs by comparing the with complete 3-D models.
HAL (Le Centre pour la Communication Scientifique Directe), 2016
Il existe de nombreuses approches permettant de modéliser la demande énergétique en chauffage-ref... more Il existe de nombreuses approches permettant de modéliser la demande énergétique en chauffage-refroidissement des bâtiments à l'échelle de la ville, mais peu sont basées sur des représentations explicites de la ville. Parmi celles-ci, encore moins permettent de calculer cette demande à un pas de temps infra-horaire. Ce défaut est mis en évidence à l'aide d'une analyse bibliographique. L'état de l'art permet aussi d'identifier les principaux axes de modélisation à améliorer dans cette optique. Nous nous intéressons en particulier à la modélisation de l'enveloppe. L'objectif est de créer un modèle de bâtiment suffisamment simple et numériquement performant pour être utilisé à l'échelle du quartier ou de la ville, tout en garantissant une précision suffisante pour la détermination de l'appel de puissance aussi bien en chauffage qu'en refroidissement. Les premiers résultats obtenus dans ce cadre sont présentés ici. MOTS-CLÉFS. chauffage et refroidissement des bâtiments ; demande de puissance ; échelle du quartier. ABSTRACT. Many approaches exist to estimate heating and cooling energy demand of buildings at city level, but few models are able to consider explicitly all buildings of the domain, and even less can determine hourly-or less-energy demand. This lack is highlighted thanks to a review of the main tools developed. The major ways of improvements are identified thanks to the state of the art of the models used, focusing on the envelope. The final objective is to develop a building model for district or city energy simulation as simple and computationally efficient as possible, able to accurately predict the heating and cooling power demand. First results obtained in this way are shown.
BS2001 vol.7, 2001
CODYBA is a software addressed to designers, teachers and research organisms. This software deter... more CODYBA is a software addressed to designers, teachers and research organisms. This software determines the energetic fluxes of a building zone. The basic data are the zones geometry and constitution. The main parameters are the climatic conditions, the internal loads and the heating and air conditioning powers, as well as their regulation mode. The graphical interface introduces concepts that are identical to those manipulated in the everyday practice by the building professionals and that are reproduced on screen by a classic "iconographical" representation in the "Windows" environment.
Fizyka Budowli w Teorii i Praktyce, 2007
Procesy przepływu masy w materiale mają wpływ nie tylko na sam materiał ale również na warunki pa... more Procesy przepływu masy w materiale mają wpływ nie tylko na sam materiał ale również na warunki panujące w pomieszczeniach z nim sąsiadujących. Opisany tutaj zostanie model transportu pary wodnej w materiale budowlanym. Po walidacji wprowadzony do niego zostanie model histerezy sorpcji. Ostatecznie zaprezentowane zostanie porównanie wyników symulacji przepływu masy w materiale dla modelu bez i z histerezą.
Energy and Buildings, 2015
Abstract High performance simulation of low energy building requires ever more accurate descripti... more Abstract High performance simulation of low energy building requires ever more accurate descriptions of the systems under study to improve the building's performance. This paper describes a numerical model to simulate a single room, using a three-dimensional description of heat conduction in the envelope with environmental conditions that vary over short time-steps are described. The simulation considers the projection of solar radiation through a window onto interior walls. The indoor air temperature is assumed to be uniform. The temperature of the inner and outer surface of the walls are calculated at each time step using a variable-step solver. Validation of the model was carried out using experimental data from a low energy cell operating in a natural climate. A set of well-calibrated temperature sensors and an infrared camera have been used to accurately measure the cell's thermal behavior. Comparison between experimental data and numerical results for free varying conditions shows good agreement and the reliability of the model is proven. These validated results were found for a highly insulated cell. Future studies for different thermal mass cells, with new materials, will be realized to show the contribution of this model. Thermal comfort will also be studied.
Elsevier eBooks, 1986
RESUME Nous presentons ici une methode d'evaluation de la qualite thermique des bâtiments dev... more RESUME Nous presentons ici une methode d'evaluation de la qualite thermique des bâtiments devant deboucher sur le calcul d'un “indice de qualite”. Cet indice est destine a renseigner le concepteur sur les ambiances thermiques qui se creent dans les locaux et vient completer l'information donnee par le besoin energetique. Ces deux grandeurs sont censees caracteriser la performance thermique. MOTS CLES, Performance thermique; indice de qualite des ambiances; confort thermique; dualite energie-confort.
Building Simulation Conference Proceedings
International audienc
Les parois legeres contenant des materiaux a changement de phase (MCP) constituent une solution a... more Les parois legeres contenant des materiaux a changement de phase (MCP) constituent une solution au manque d’inertie des bâtiments a structure legere. Cependant, aucune valeur du coefficient d’echange convectif aux abords ce type de paroi n’a encore ete determinee afin de permettre la validation numerique de leur efficacite energetique. C’est pourquoi une etude des echanges convectifs aux abords de parois MCP a ete realisee dans le cadre de cette these. La these comporte un volet theorique sur le couplage air / paroi en regime instationnaire, et un volet experimental. Le volet theorique a permis de montrer que la capacite calorifique des parois legeres de bâtiment est trop elevee pour que des phenomenes transitoire de type “effet de bord d’attaque" puisse se produire dans la couche limite. Un modele simple base sur la methode de Von-Karmann Polhaussen a ete developpe afin de quantifier les effets d’une stratification thermique lineaire sur les profils de temperature a la paroi d...
Building Simulation Conference proceedings
Explicit simulations of the building heating and cooling loads at the district scale is hard to a... more Explicit simulations of the building heating and cooling loads at the district scale is hard to achieve because of their huge computational cost and the lack of relevant data at such an urban scale. A common solution to answer both problems is to simplify the model, usually resulting in a lower accuracy. This issue rises the following question: how to design a district energy model given computational limitations ? A specific modelling and simulation platform, called MoDEM (Modular District Energy Model), was developed to answer this question. The level of details of the model is modular in order to fit the available data or the available computational resources. For both cases, the impact of the assumptions can be evaluated as well as the loss of accuracy. To illustrate the possibilities offered by the platform, a district is taken as a use case. The results are discussed regarding the effects of various model adaptations on simulation outputs. The introduced methodology evidences the steps making it possible to reach explicit simulations of the energy load of a district and demonstrates the ability, and the limitations, of current tools.
International Journal of Ventilation, 2004
Abstract This paper presents a three-dimensional zonal model, ZAER, for heat transfer and air flo... more Abstract This paper presents a three-dimensional zonal model, ZAER, for heat transfer and air flow calculations. It is based on an intermediate approach between single-air-node and CFD models. The indoor air volume is divided into macroscopic homogeneous zones. Heat and mass balance equations are written for each zone, while the mass flow rates across the interfaces are calculated by power pressure laws. The simulation tool ZAER allows the determination of temperature fields and air flow distributions inside unconditioned buildings, taking into account external boundary conditions. We also present an experimental validation of the model by comparing its predictions with experimental data obtained from measurements on the experimental cell Minibat (CETHIL, INSA Lyon Laboratory), for different configurations. The results obtained are in good agreement with experimental data, and suggest that the ZAER model is an appropriate tool to assess satisfactorily temperature heterogeneity and air movement within a room.
Revue de Physique Appliquée, 1990
L'étude présentée porte sur la comparaison des différents modèles de représentation des échanges ... more L'étude présentée porte sur la comparaison des différents modèles de représentation des échanges thermiques entre le corps humain et l'enceinte dans laquelle il se trouve. Il s'agit des modèles danois
HAL (Le Centre pour la Communication Scientifique Directe), Oct 22, 2008
Building Simulation Conference Proceedings
Roles of urban energy simulation become important for sustainable city design and energy manageme... more Roles of urban energy simulation become important for sustainable city design and energy management. In this context, a single reduced model that can describe a number of buildings is proposed and tested in this paper. Simulation results show that the proposed single reduced model for multiple buildings can give very similar results with separate reduced models in load calculation. However, the calculation time of the single reduced model is more important than the case of several reduced models because the PID controller used in Dymola to calculate building loads requires more iterations for a MIMO (multi inputs and multi outputs) system than a SISO (single input and single output). In conclusion, the use of a single reduced model can be a solution for urban energy simulation, but further work is needed to simplify calculation processes by an optimal solver.
In order to locally produce electricity in urban areas, it is important to properly assess the po... more In order to locally produce electricity in urban areas, it is important to properly assess the potential of the Buildings Integrated PhotoVoltaic (BIPV) technologies. Therefore, the evaluation of the incident solar radiative flux in dense urban areas, taking into account multiple reflections over all urban elements, is a current subject of interest. Although different models exist to evaluate the intensity of the power density on each zone of each part of an urban scene, the reflective properties of the different urban materials are generally simplified, and they are commonly supposed to reflect uniformly wavelength through the space. Henceforth, this brings up questions about the relevance of these assumptions and their influence in the numerical evaluation of the PhotoVoltaic (PV) potential. Thus, this paper reviews the different alternatives to proceed with a preliminary evaluation of the solar potential in dense urban areas, with the aim of evaluating the influence of the materi...
Journal of Central South University, 2014
ABSTRACT Multi-dimensional heat transfers modeling is crucial for building simulations of insulat... more ABSTRACT Multi-dimensional heat transfers modeling is crucial for building simulations of insulated buildings, which are widely used and have multi-dimensional heat transfers characteristics. For this work, state-model-reduction techniques were used to develop a reduced low-order model of multi-dimensional heat transfers. With hot box experiment of hollow block wall, heat flow relative errors between experiment and low-order model predication were less than 8% and the largest errors were less than 3%. Also, frequency responses of five typical walls, each with different thermal masses or insulation modes, the low-order model and the complete model showed that the low-order model results agree very well in the lower excitation frequency band with deviations appearing only at high frequency. Furthermore, low-order model was used on intersection thermal bridge of a floor slab and exterior wall. Results show that errors between the two models are very small. This low-order model could be coupled with most existing simulation software for different thermal mass envelope analyses to make up for differences between the multi-dimensional and one-dimensional models, simultaneously simplifying simulation calculations.
Proceedings of International Symposium on Convective Heat and Mass Transfer in Sustainable Energy, 2009
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Papers by Jean-jacques Roux