This work is a multidisciplinary approach of natural ventilation in hot and humid climates. Our a... more This work is a multidisciplinary approach of natural ventilation in hot and humid climates. Our aim is the control of thermal comfort in tropical towns. We evaluate the natural ventilation potential of different shapes of the dense housing. We present here the result we obtained in the case of areas in chequered plan of colonial type ( . We model the quarter and simulate the airflow induced by wind around the buildings using a CFD code. This allows us to calculate the difference of pressure that appears between upwind and downwind sides of each house. From this result, we establish simple rules that can be used by designers. Figure 1: Details of a cluster of buildings within the historical district of Cayenne, French Guyana.
Vertigo La Revue Electronique En Sciences De L Environnement, May 15, 2012
Dans cette contribution, nous positionnons le champ de recherche qui concerne l'étude des microcl... more Dans cette contribution, nous positionnons le champ de recherche qui concerne l'étude des microclimats urbains par rapport aux problématiques actuelles du développement urbain durable et par rapport aux champs de recherche voisins. En effet, pour proposer des solutions en réponse au changement climatique, ce champ de recherche doit aborder ses objets de recherche (forme urbaine, occupation des sols, trame vert, activités humaines…) différemment. Par ailleurs, dans un contexte de développement durable, ces objets sont maintenant étudiés comme étant au croisement de multiples enjeux environnementaux, sociaux et économiques. Nous explorons ces échanges entre disciplines en nous intéressant plus particulièrement au cas de l'objet de recherche que constituent les trames vertes. Dans un premier temps, nous expliquons en quoi les trames vertes intéressent les sciences du microclimat urbain. Nous faisons à cette occasion un point sur les connaissances actuelles du rôle climatique des trames vertes et les perspectives de recherche. Ces perspectives mettent en évidence la nécessité qui s'impose aux chercheurs de disposer de connaissances, méthodes et techniques venant d'autres champs disciplinaires. Nous explicitons certains des points d'articulation avec la géomatique, la biologie végétale, l'hydrologie, etc. occasionnés par cet objet d'étude. Nous montrons également en quoi les connaissances issues de la micro-climatologie urbaine peuvent être utiles dans d'autres domaines.
This study consists in showing that it is possible to automatically build zonal models that allow... more This study consists in showing that it is possible to automatically build zonal models that allow to predict air movement, temperature distribution and air quality in the whole building. Zonal models are based on a rough partitioning of the rooms. It is an intermediate approach between one-node models and CFD models. One-node models consider an homogeneous temperature in each room, and for that reason, do not permit to predict the thermal comfort in a room whereas CFD models require a great amount of simulation time To achieve this aim, the zonal model was entirely reformulated as the connection of small sets of equations. The equations describe, either the state of a sub-zone of the partitioning (such sets of equations are called « cells »), or mass and energy transfers that occur between two sub-zones (then, they are called « interfaces »). There are various « cells » and « interfaces » to represent different air flows that occur in buildings. They all have been translated into SPARK objects that form a model library. Building a simulation consists in choosing the appropriate models to represent the rooms, and connecting them. The last stage has been automated. So, the only thing the user has to do is to give the partitioning and to choose the models to be implemented. The resulting set of equations is solved iteratively with SPARK. Results of simulations in 3D-rooms are presented and compared with experimental data. Examples of zonal models are also given. They are applied to the study of a group of two rooms, a building, and a room the geometry of which is complex.
Sustainable urban development requires a reconfiguration of the traditional processes towards a n... more Sustainable urban development requires a reconfiguration of the traditional processes towards a new approach that raises the question of the integration of environmental data in the design, as well as the evaluation of urban projects. This new approach implies to manage heterogeneous parameters and to improve concertation processes. Therefore, the place of the Geographical Information Systems (GIS) in such a process has to be questioned. In the first section, this paper explores the issue of the sustainability indicators. The results of a survey are presented and discussed. This survey of urban research stackeholders highlighted their various waitings for GIS tools, and the complexity of the set of problems. The description of benefits and limits of GIS in this context is discussed in the second section.
The radiative characteristics of buildings' envelops and their geometrical arrangement in the cit... more The radiative characteristics of buildings' envelops and their geometrical arrangement in the city play an important role in the urban heat island (UHI) phenomenon that modifies buildings' energy consumption. We focus on one parameter of direct relevance to UHI: the albedo. The albedo of a city or a district depends on surfaces' arrangement, materials, and solar position. We study these dependences through the calculation of the albedo for urban blocks in the case of a real urban project in France. After having regrouped the radiative characteristics of materials used in this project, we computed solar fluxes over a day, at several dates in a year with the SOLENE software to obtain albedos. This study, can be used to increase the awareness of urban planners, designers and decision makers on the importance of the choice of coating, paving and roof materials related to their effect on local climate and on energy consumption of buildings. Materials' albedo should be chosen differently in function of surface's location. For these urban blocks, morphological parameters are evaluated and correlations researched between them and calculated albedos to propose an indicator that characterizes the contribution of a district (real or at planning stage) to UHI.
This paper introduces a 3D environmental urban information system which is to help urban designer... more This paper introduces a 3D environmental urban information system which is to help urban designers and developers to analysing and evaluating the environmental impacts of their urban projects. Where urban data is acquired from 3D urban models and environmental data is often coming from simulation software. For realizing environmental impacts analysis, the environmental urban information must be embedded into urban information system. However, environmental data from different simulations is heterogeneous, especially in geometry. It is not easy to modelling common geometrical descriptions for all kinds of environmental data. In this case, the data of simulations can be inputted in different geo-database, but some queries basing on different environmental conditions will be not applied. Therefore, basing on regular meshes (both in 2D and in 3D), an approach for integrating environmental data in a same geo-database will be proposed. The approaches for integrating these data into one geo-database bring out some uncertainty. Looking for an approach for integrating environmental data that causes less uncertainty in the result is necessary. We discuss some uncertainty of integration process and introduce a solution for reducing the uncertainty.
The aim of this paper is to present an automatic generator of zonal models that makes it possible... more The aim of this paper is to present an automatic generator of zonal models that makes it possible to free the user from the choice of the specific flows models that have to be implemented in the zonal model and from the partitioning stage. The dynamic simulation tool called "O-Zone" is based on an advanced formulation of zonal models. It uses on a new way of sub-dividing the room that allows us to obtain a dynamic partitioning based on airflow patterns. The partitioning method chosen is the Octree method. It is a hierarchical representation of the space based on the successive and recursive subdivision of a cube in eight smaller cubes.
This paper develops a method to study how the performance at urban districts scale arranges the b... more This paper develops a method to study how the performance at urban districts scale arranges the building heights regularly such as the weighted façade area of solar duration ( oriented façades to predict and quantify the impact of furthermore on buildings' energy consumption
This paper provides a synthesis of three complementary research works that contribute to the same... more This paper provides a synthesis of three complementary research works that contribute to the same objective: proposing solutions to reduce building energy consumption by modifying local climate. The first work explores urban forms: it proposes methods to describe them and analyze the climatic performances of classified urban forms. The second one focuses on one parameter of direct relevance to urban heat island phenomenon: the surface albedo. The albedo of a city or a district depends on surfaces' arrangement, materials used for roofs, paving, coatings, etc., and solar position. The third one proposes a simulation tool that permits to evaluate the impact outdoor urban environment on buildings' energy consumption. This analysis permits us to propose morphology indicators to compare the relative efficiencies of different typologies. The conclusion discusses the relevance of using indicators (based on physics or morphology, related to site or to built form) in urban design process and proposes a methodology to produce indicators.
This paper presents the concept of a tool adapted to zonal models and devoted to the simulation o... more This paper presents the concept of a tool adapted to zonal models and devoted to the simulation of thermal dynamic phenomena in buildings. The aim of this tool is the automatic generation of zonal models requiring the minimum user's expertise.
This paper discusses how to make urban climatology a better help for the formulation of urban des... more This paper discusses how to make urban climatology a better help for the formulation of urban design guidelines. Therefore it restudies the relationship between urban climatology and urban design. It proposes a cooperation mode to make more effective communication between urban climatology and urban design: the appropriate urban form description methods at the beginning and the pertinent expression form of guidelines at the end of the mode. And then it suggests a research frame dedicated to urban design guidelines in hot-summer and cold-winter area, and takes the Sixin project for example to explore how to express climatic design guidelines for urban forms control.
This paper presents the conception of a tri-dimensional geographical information system applied t... more This paper presents the conception of a tri-dimensional geographical information system applied to domains of architectural & urban planning, and introduces an approach to integrate the environmental urban data into this system. The development of this system aims at being able to store, manage, analyze and visualize urban objects (buildings, streets, external spaces, etc.), urban morphology (density, form, orientation, etc.) and environmental information (temperature, sunlight and sunshine duration, air movement, sound, etc.). This approach will help architects and urban designers to evaluating the environmental impacts of their urban projects (e.g., creation a new building block, renovation of housing, operation of urban renewal, etc).
In our formulation of zonal models for calculating room air temperature and flow distributions, t... more In our formulation of zonal models for calculating room air temperature and flow distributions, the behavior of a room is represented by the connection of SPARK calculation modules. Modules to describe the building walls and various systems have been created. They form the models library. By assembling the appropriate modules, a zonal model of an entire building can be constructed. A model-generating tool called GenSPARK automates this process. SPARK solves the set of equations resulting from this construction to obtain the air flow and temperature distribution in the building. We describe our formulation of zonal models, show how GenSPARK works and give examples of configurations we are able to analyze.
Plume's convector modeling for object-oriented thermal building s... more Plume's convector modeling for object-oriented thermal building simulation software SPARK. In this paper, a zonal model used to predict air movement and temperature distribution in a room is presented. This model is based on a rough partitioning of the room: it is an intermediate approach between one-node models (that consider a homogeneous temperature in each room) and CFD models. Flow
Les systèmes d'information géographique ont un rôle important à jouer en matière de développement... more Les systèmes d'information géographique ont un rôle important à jouer en matière de développement durable urbain, tant pour ce qui concerne la collecte et l'analyse des propriétés environnementales des constructions et des espaces urbains, qu'en matière de communication et de concertation autour de ces enjeux dans les projets d'aménagement. À cette fin, les SIG doivent savoir prendre en compte la troisième dimension et s'interfacer avec des outils de simulation des phénomènes physiques urbains. Cet article présente une tentative de réponse à ces objectifs. Nous exposons la structure d'un SIG 3D environnemental urbain, actuellement développé et mis en oeuvre dans des situations concrètes à Nantes, ainsi que les modalités d'intégration des données environnementales urbaines dans ce système.
ABSTRACT To streamline the design of the energy efficient buildings, appropriate tools are needed... more ABSTRACT To streamline the design of the energy efficient buildings, appropriate tools are needed to assess their energy performance taking into account the microclimatic context.Numerical simulation seems to be the most suitable issue, but none tool is dedicate to the direct evaluation of the microclimate influence on the building energy consumption. A complete solution could be to use both CFD and thermoradiative simulation tools complementary with the coupling technique perspective. This paper presents both a developed CFD–thermoradiative coupled simulation tool and a typical application on an urban fragment.The results lead to two kind of observations:•Integration of the thermal model of a building in the microclimatic simulation platform enable a quantitative evaluation of the building energy demand regarding different urban design scenarii (e.g. mineralized vs vegetated).•Different physical phenomena do not contribute as much in the energy balance and it is important to compute precisely each one to obtain the small scale microclimatic influence.
The necessity of focus on more large integration of passive concepts for indoor climate condition... more The necessity of focus on more large integration of passive concepts for indoor climate conditioning is today a reality. Through this study, a contribution to fill the lack of useful design guidelines for natural ventilation is proposed, in order to develop the passive ventilation systems implementation. Besides a methodological approach, the paper proposes conceptual tools. The implementation of a natural ventilation strategy includes the envelope building design, the indoor spaces layout and the component sizing. This study explores an architectural classification of ventilation systems. The ventilation system involvement is underlined through evaluation of ventilation efficiency concerning two natural ventilation systems using ducts.
This work is a multidisciplinary approach of natural ventilation in hot and humid climates. Our a... more This work is a multidisciplinary approach of natural ventilation in hot and humid climates. Our aim is the control of thermal comfort in tropical towns. We evaluate the natural ventilation potential of different shapes of the dense housing. We present here the result we obtained in the case of areas in chequered plan of colonial type ( . We model the quarter and simulate the airflow induced by wind around the buildings using a CFD code. This allows us to calculate the difference of pressure that appears between upwind and downwind sides of each house. From this result, we establish simple rules that can be used by designers. Figure 1: Details of a cluster of buildings within the historical district of Cayenne, French Guyana.
Vertigo La Revue Electronique En Sciences De L Environnement, May 15, 2012
Dans cette contribution, nous positionnons le champ de recherche qui concerne l'étude des microcl... more Dans cette contribution, nous positionnons le champ de recherche qui concerne l'étude des microclimats urbains par rapport aux problématiques actuelles du développement urbain durable et par rapport aux champs de recherche voisins. En effet, pour proposer des solutions en réponse au changement climatique, ce champ de recherche doit aborder ses objets de recherche (forme urbaine, occupation des sols, trame vert, activités humaines…) différemment. Par ailleurs, dans un contexte de développement durable, ces objets sont maintenant étudiés comme étant au croisement de multiples enjeux environnementaux, sociaux et économiques. Nous explorons ces échanges entre disciplines en nous intéressant plus particulièrement au cas de l'objet de recherche que constituent les trames vertes. Dans un premier temps, nous expliquons en quoi les trames vertes intéressent les sciences du microclimat urbain. Nous faisons à cette occasion un point sur les connaissances actuelles du rôle climatique des trames vertes et les perspectives de recherche. Ces perspectives mettent en évidence la nécessité qui s'impose aux chercheurs de disposer de connaissances, méthodes et techniques venant d'autres champs disciplinaires. Nous explicitons certains des points d'articulation avec la géomatique, la biologie végétale, l'hydrologie, etc. occasionnés par cet objet d'étude. Nous montrons également en quoi les connaissances issues de la micro-climatologie urbaine peuvent être utiles dans d'autres domaines.
This study consists in showing that it is possible to automatically build zonal models that allow... more This study consists in showing that it is possible to automatically build zonal models that allow to predict air movement, temperature distribution and air quality in the whole building. Zonal models are based on a rough partitioning of the rooms. It is an intermediate approach between one-node models and CFD models. One-node models consider an homogeneous temperature in each room, and for that reason, do not permit to predict the thermal comfort in a room whereas CFD models require a great amount of simulation time To achieve this aim, the zonal model was entirely reformulated as the connection of small sets of equations. The equations describe, either the state of a sub-zone of the partitioning (such sets of equations are called « cells »), or mass and energy transfers that occur between two sub-zones (then, they are called « interfaces »). There are various « cells » and « interfaces » to represent different air flows that occur in buildings. They all have been translated into SPARK objects that form a model library. Building a simulation consists in choosing the appropriate models to represent the rooms, and connecting them. The last stage has been automated. So, the only thing the user has to do is to give the partitioning and to choose the models to be implemented. The resulting set of equations is solved iteratively with SPARK. Results of simulations in 3D-rooms are presented and compared with experimental data. Examples of zonal models are also given. They are applied to the study of a group of two rooms, a building, and a room the geometry of which is complex.
Sustainable urban development requires a reconfiguration of the traditional processes towards a n... more Sustainable urban development requires a reconfiguration of the traditional processes towards a new approach that raises the question of the integration of environmental data in the design, as well as the evaluation of urban projects. This new approach implies to manage heterogeneous parameters and to improve concertation processes. Therefore, the place of the Geographical Information Systems (GIS) in such a process has to be questioned. In the first section, this paper explores the issue of the sustainability indicators. The results of a survey are presented and discussed. This survey of urban research stackeholders highlighted their various waitings for GIS tools, and the complexity of the set of problems. The description of benefits and limits of GIS in this context is discussed in the second section.
The radiative characteristics of buildings' envelops and their geometrical arrangement in the cit... more The radiative characteristics of buildings' envelops and their geometrical arrangement in the city play an important role in the urban heat island (UHI) phenomenon that modifies buildings' energy consumption. We focus on one parameter of direct relevance to UHI: the albedo. The albedo of a city or a district depends on surfaces' arrangement, materials, and solar position. We study these dependences through the calculation of the albedo for urban blocks in the case of a real urban project in France. After having regrouped the radiative characteristics of materials used in this project, we computed solar fluxes over a day, at several dates in a year with the SOLENE software to obtain albedos. This study, can be used to increase the awareness of urban planners, designers and decision makers on the importance of the choice of coating, paving and roof materials related to their effect on local climate and on energy consumption of buildings. Materials' albedo should be chosen differently in function of surface's location. For these urban blocks, morphological parameters are evaluated and correlations researched between them and calculated albedos to propose an indicator that characterizes the contribution of a district (real or at planning stage) to UHI.
This paper introduces a 3D environmental urban information system which is to help urban designer... more This paper introduces a 3D environmental urban information system which is to help urban designers and developers to analysing and evaluating the environmental impacts of their urban projects. Where urban data is acquired from 3D urban models and environmental data is often coming from simulation software. For realizing environmental impacts analysis, the environmental urban information must be embedded into urban information system. However, environmental data from different simulations is heterogeneous, especially in geometry. It is not easy to modelling common geometrical descriptions for all kinds of environmental data. In this case, the data of simulations can be inputted in different geo-database, but some queries basing on different environmental conditions will be not applied. Therefore, basing on regular meshes (both in 2D and in 3D), an approach for integrating environmental data in a same geo-database will be proposed. The approaches for integrating these data into one geo-database bring out some uncertainty. Looking for an approach for integrating environmental data that causes less uncertainty in the result is necessary. We discuss some uncertainty of integration process and introduce a solution for reducing the uncertainty.
The aim of this paper is to present an automatic generator of zonal models that makes it possible... more The aim of this paper is to present an automatic generator of zonal models that makes it possible to free the user from the choice of the specific flows models that have to be implemented in the zonal model and from the partitioning stage. The dynamic simulation tool called "O-Zone" is based on an advanced formulation of zonal models. It uses on a new way of sub-dividing the room that allows us to obtain a dynamic partitioning based on airflow patterns. The partitioning method chosen is the Octree method. It is a hierarchical representation of the space based on the successive and recursive subdivision of a cube in eight smaller cubes.
This paper develops a method to study how the performance at urban districts scale arranges the b... more This paper develops a method to study how the performance at urban districts scale arranges the building heights regularly such as the weighted façade area of solar duration ( oriented façades to predict and quantify the impact of furthermore on buildings' energy consumption
This paper provides a synthesis of three complementary research works that contribute to the same... more This paper provides a synthesis of three complementary research works that contribute to the same objective: proposing solutions to reduce building energy consumption by modifying local climate. The first work explores urban forms: it proposes methods to describe them and analyze the climatic performances of classified urban forms. The second one focuses on one parameter of direct relevance to urban heat island phenomenon: the surface albedo. The albedo of a city or a district depends on surfaces' arrangement, materials used for roofs, paving, coatings, etc., and solar position. The third one proposes a simulation tool that permits to evaluate the impact outdoor urban environment on buildings' energy consumption. This analysis permits us to propose morphology indicators to compare the relative efficiencies of different typologies. The conclusion discusses the relevance of using indicators (based on physics or morphology, related to site or to built form) in urban design process and proposes a methodology to produce indicators.
This paper presents the concept of a tool adapted to zonal models and devoted to the simulation o... more This paper presents the concept of a tool adapted to zonal models and devoted to the simulation of thermal dynamic phenomena in buildings. The aim of this tool is the automatic generation of zonal models requiring the minimum user's expertise.
This paper discusses how to make urban climatology a better help for the formulation of urban des... more This paper discusses how to make urban climatology a better help for the formulation of urban design guidelines. Therefore it restudies the relationship between urban climatology and urban design. It proposes a cooperation mode to make more effective communication between urban climatology and urban design: the appropriate urban form description methods at the beginning and the pertinent expression form of guidelines at the end of the mode. And then it suggests a research frame dedicated to urban design guidelines in hot-summer and cold-winter area, and takes the Sixin project for example to explore how to express climatic design guidelines for urban forms control.
This paper presents the conception of a tri-dimensional geographical information system applied t... more This paper presents the conception of a tri-dimensional geographical information system applied to domains of architectural & urban planning, and introduces an approach to integrate the environmental urban data into this system. The development of this system aims at being able to store, manage, analyze and visualize urban objects (buildings, streets, external spaces, etc.), urban morphology (density, form, orientation, etc.) and environmental information (temperature, sunlight and sunshine duration, air movement, sound, etc.). This approach will help architects and urban designers to evaluating the environmental impacts of their urban projects (e.g., creation a new building block, renovation of housing, operation of urban renewal, etc).
In our formulation of zonal models for calculating room air temperature and flow distributions, t... more In our formulation of zonal models for calculating room air temperature and flow distributions, the behavior of a room is represented by the connection of SPARK calculation modules. Modules to describe the building walls and various systems have been created. They form the models library. By assembling the appropriate modules, a zonal model of an entire building can be constructed. A model-generating tool called GenSPARK automates this process. SPARK solves the set of equations resulting from this construction to obtain the air flow and temperature distribution in the building. We describe our formulation of zonal models, show how GenSPARK works and give examples of configurations we are able to analyze.
Plume's convector modeling for object-oriented thermal building s... more Plume's convector modeling for object-oriented thermal building simulation software SPARK. In this paper, a zonal model used to predict air movement and temperature distribution in a room is presented. This model is based on a rough partitioning of the room: it is an intermediate approach between one-node models (that consider a homogeneous temperature in each room) and CFD models. Flow
Les systèmes d'information géographique ont un rôle important à jouer en matière de développement... more Les systèmes d'information géographique ont un rôle important à jouer en matière de développement durable urbain, tant pour ce qui concerne la collecte et l'analyse des propriétés environnementales des constructions et des espaces urbains, qu'en matière de communication et de concertation autour de ces enjeux dans les projets d'aménagement. À cette fin, les SIG doivent savoir prendre en compte la troisième dimension et s'interfacer avec des outils de simulation des phénomènes physiques urbains. Cet article présente une tentative de réponse à ces objectifs. Nous exposons la structure d'un SIG 3D environnemental urbain, actuellement développé et mis en oeuvre dans des situations concrètes à Nantes, ainsi que les modalités d'intégration des données environnementales urbaines dans ce système.
ABSTRACT To streamline the design of the energy efficient buildings, appropriate tools are needed... more ABSTRACT To streamline the design of the energy efficient buildings, appropriate tools are needed to assess their energy performance taking into account the microclimatic context.Numerical simulation seems to be the most suitable issue, but none tool is dedicate to the direct evaluation of the microclimate influence on the building energy consumption. A complete solution could be to use both CFD and thermoradiative simulation tools complementary with the coupling technique perspective. This paper presents both a developed CFD–thermoradiative coupled simulation tool and a typical application on an urban fragment.The results lead to two kind of observations:•Integration of the thermal model of a building in the microclimatic simulation platform enable a quantitative evaluation of the building energy demand regarding different urban design scenarii (e.g. mineralized vs vegetated).•Different physical phenomena do not contribute as much in the energy balance and it is important to compute precisely each one to obtain the small scale microclimatic influence.
The necessity of focus on more large integration of passive concepts for indoor climate condition... more The necessity of focus on more large integration of passive concepts for indoor climate conditioning is today a reality. Through this study, a contribution to fill the lack of useful design guidelines for natural ventilation is proposed, in order to develop the passive ventilation systems implementation. Besides a methodological approach, the paper proposes conceptual tools. The implementation of a natural ventilation strategy includes the envelope building design, the indoor spaces layout and the component sizing. This study explores an architectural classification of ventilation systems. The ventilation system involvement is underlined through evaluation of ventilation efficiency concerning two natural ventilation systems using ducts.
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Papers by Marjorie Musy