Francis Allard

• Professeur, Docteur d'Etat ès Sciences
• Professor (Full) at La Rochelle Université

Urban courtyards are well known for their potential thermal performances in vernacular urban morphology. Furthermore, in a more general approach considering various cities and locations, new building uses, and climate changes, a correct courtyard design requires an accurate understanding of the complex interactions between buildings and their surro...

The existing building stock represents a major challenge for a successful energy transition and achieving zero carbon territories. Several thermal simulation tools have integrated optimization modules for building design and retrofit. However, in these tools there are problems of convergence towards local optimum and the unknown computation time. I...

This paper presents a summary of the main developments and results achieved in the frame-work of the French research project called EVAL-SDS. This project aims to analyse the performance of Natural, i.e. without use of fan for extraction, Soil Depressurization Systems (NSDS) to protect the built indoor environment from soil gaseous pollutant (Radon...

For the energy-related issues that the world is facing nowadays, the renovation of the building stock is one of the major challenges. The objective of this study is to present an approach that helps to develop a multi-criteria decision support tool dedicated to the rehabilitation of sustainable and passive energy housing by integrating heating ener...

This study presents a fast and nonintrusive in situ methodology to characterise the Volatile Organic Compounds (VOCs) fluxes of contaminated sites and to quantify their intrusion into future buildings built on these sites. It could be used to conduct exhaustive ground pre-characterisation and indoor air assessments for future on-site buildings. The...

Containment of dispersion of particulate pollutants remains as a major concern for pharmaceutical, xerography, microelectronic and semiconductor industries. Electrostatic precipitation proves out to be the most feasible and viable technology for containing the spread of such hazardous pollutants. The present study focuses on the simulation of parti...

Dear Colleagues, on behalf of the Organizers, it is our great pleasure and an honor to welcome you to the X IAQVEC 2019: nearly Zero Energy Buildings, which will be held on September 5 to 7 in Bari, Italy. The Conference was hosted by the Politecnico di Bari and co-organized by three universities, the Ryerson University (Ontario, Canada), the Polit...

The entry of soil gas pollutants into buildings has been the subject of many studies and some analytical airflow models have been developed to estimate this entry into buildings. The existing airflow models do not include the sub-slab gravel layer that can influence significantly the airflow from soil into buildings. In this paper, an analytical ai...

In France, almost 75% to 90% of the existing buildings will always persist in 2050. In fact, the thermal refurbishment rate of the existing residential buildings which present a high potential in energy saving, is estimated less than 1% per year. In the aim of accelerating this renovation rate till 3% per year and having the autonomous energy build...

In Europe, almost 75% of the existing buildings will always persist in 2050. In fact, the thermal refurbishment rate of the existing residential buildings which present a high potential in energy saving, is estimated less than 1% per year. In the aim of accelerating this renovation rate till 3% per year, seeking optimal technical solutions taking i...

In most buildings, heating, ventilation and air conditioning (HVAC) systems are controlled by indoor air temperature. However, the temperature sensor is often misplaced in the building and the measured temperature is not representative of the perceived temperature. In a context where the buildings must ensure good thermal comfort for the occupants...

High global performance in buildings (energy, environmental, economic and social) is in growing demand. The research focuses on a new assessment method to determine how an integrated system impacts the building’s global performance. This approach is tested on the External Thermal Insulation Composite Systems (ETICS). In order to define the global p...

The building sector is the largest consumer of energy in Morocco with a share of about 36% of the overall energy consumption of the country. This rate is likely to increase if the new buildings are energy consuming. In order to achieve a high energy performance of the building, an optimization of the building envelope is required. This study is oft...

The entry and the accumulation of soil gas pollutants (Radon, VOC's, …) into indoor environments can cause significant health risks. Some analytical and numerical models have been developed to quantify the soil gas indoor concentrations in order to assess their health risks. However, the different models include large uncertainties in understanding...

The entry of soil gas pollutants (Radon, VOCs,…) into buildings can cause serious health risks to inhabitants. Various systems have been developed to limit this risk. Soil Depressurization System (SDS) is one of the most efficient mitigation systems to prevent buildings against these pollutants. Two operating modes of SDS are currently used: active...

High global performance in buildings (energy, environmental, economic and social) is in growing demand. Furthermore, the construction systems, components, materials and buildings must satisfy 7 basic requirements in accordance with the European regulation. They focus on ‘mechanical resistance and stability’, ‘safety in case of fire’, ‘hygiene, heal...

The entry of soil gas pollutants (Radon, VOCs, etc.) into the buildings are known to create serious health risks to building's occupants, and various systems have been developed to lower this risk. Soil Depressurization Systems (SDS) are among the most efficient mitigation systems protecting buildings against soil gas pollutants. In a recent study...

The aim of this paper is to develop an optimization algorithm to control the temperature in the occupation zone, using reduced-order approaches based on POD. Two methods are employed here: an adjoint-equations method and a based response surface method. These are tested on the cases of a lid-driven cavity heated by the left and a 3D ventilated cavi...

In order to provide comfort in a low energy consumption building, it is preferable to use natural ventilation rather than HVAC systems. To achieve this, engineers need tools that predict the heat and mass transfer between the building's interior and exterior. This paper presents a method implemented in some building software, and the results are co...

a b s t r a c t Energy performance of air conditioned buildings and summer comfort can be improved with high solar reflectance and high emittance of building envelopes. Widely used for roofs, this technique known as cool roof, has a direct impact on the external surface temperatures peaks which reduces both heat transfer to the building and to the...

Soil gas pollutant intrusion into buildings has been the subject of many studies, but as yet no tool allows a reasonable estimation to be obtained. This is due to complex phenomenologies that need to be taken into account and particularly to the difficulty in estimating pollutant flows at ground-building interface. In this paper, analytical models...

Natural ventilation is more and more encouraged in order to reduce the costs related to air conditioning systems during summer. Natural ventilation enables to cool down buildings'indoor environment at low cost, by simply opening and closing the windows. However, it is difficult to control air flow rate which explains why mechanical ventilation syst...

Soil gas pollutants (VOCs, radon, …) have long been known to intrude into buildings through various openings, e.g., cracks and gaps in the foundations. As yet no model has been developed which can quantify this rate of flow whilst taking into account various substructure configurations. This is due to the complex phenomena that need to be consider...

The refurbishment of building roofs with cool selective coatings is already defined by some standards. Impacts on urban heat island (UHI) and thermal performance of buildings are well identified. In France, most of the developments on building thermal performances are focused on the building envelope insu-lation, especially for the winter energy pe...

Dans cette communication, une nouvelle méthode de construction de modèles d'ordre réduit, obtenus à partir de bases POD, est exposée pour des fluides incompressibles en anisotherme. Cette méthode, appelée projection optimale permet d'avoir l'évolution temporelle à la fois du champ de vitesse, de la température et de la pression. Elle est fondée sur...

a b s t r a c t The refurbishment of building roofs with cool selective coatings is already defined by some standards. Impacts on urban heat island (UHI) and thermal performance of buildings are well identified. In France, most of the developments on building thermal performances are focused on the building envelope insu-lation, especially for the...

Ventilation systems are primarily designed for ensuring good indoor air quality (IAQ). However, building energy requirements tend to put demand on reducing air change rates. The assessment of the performance of ventilation systems over long periods has thus become a subject of importance. In this framework, five ventilation systems were investigate...

The coupled heat, air and moisture transfer between building envelopes and indoor air is complicated, and has a significant influence on the indoor environment and the energy performance of buildings. In the paper, a model for predicting coupled multi-zone hygrothermal-airflow transfer is presented. Both heat and moisture transfer in the building e...

This paper presents an innovative concept for optimized air diffusion in buildings. The method uses passive control of air jet through lobed diffusers. An analysis is done experimentally at different scales for a lobed shaped geometry. A cross-shaped jet is characterized first through an isolated orifice and then at the scale of one perforated pane...

The following paper focuses on the study of the ability and the efficiency of passive Soil Depressurisation System which helps to prevent buildings from gaseous pollutants coming from the ground. The Soil Depressurisation System (S.D.S.) is one of the most effective methods of lowering gaseous pollutants (radon) levels and for remedial measures. Th...

Dispersion of ultrafine particles (less than 0.1 μm) and accumulation mode particles (0.1–2.5 μm) remains as an area of major concern to microelectronic and semiconductor industry. A possible means of containing the dispersion of particulate pollutants is to subject them to electrostatic precipitation. The present study is concerned with the disper...

In order to get a useful tool for global and long-term assessment of the performances of ventilation systems, the experimental house MARIA and ventilation systems are modeled in MATLAB/Simulink environment. This paper quickly describes the multi-zone airflow and pollutant transfer model and deals with the validation by experimental means. Firstly,...

A single-family house and its ventilation systems are simulated using SIMBAD Toolbox, a combined mass and heat transfer model implemented in MATLAB/Simulink environment. Numerical investigations are then performed with four ventilation systems for a heating period. This paper deals with the simulation results with regard to indoor air quality and e...

The French regulation on residential building ventilation relies on an overall and continuous air renewal. The fresh air should enter the building through the "habitable rooms" while the polluted air is extracted in the service rooms. In this way, internal air is drained from the lowest polluted rooms to the highest polluted ones. However, internal...

A mechanical ventilation principle used in French residential buildings was tested in the experimental house of the CSTB research centre. The experiments dealt with pollutant removal efficiency of this ventilation principle, mainly with air tightness and the influence of internal doors. Tracer gas constant injection method was used to simulate the...

A l’heure où les bâtiments doivent être construits ou rénovés en leur assurant la meilleure étanchéité à l’air, il devenait de plus en plus impératif que les systèmes de ventilation naturelle ou hybride puissent être conçus, dimensionnés et mis en œuvre dans le respect de règles communes et puissent ainsi constituer une solution alternative à la ve...

The simultaneous heat and moisture transfer in the building envelope has an important influence on the indoor environment and the overall performance of buildings. In this paper, a model for predicting whole building heat and moisture transfer was presented. Both heat and moisture transfer in the building envelope and indoor air were simultaneously...

Cooling energy refurbishment of buildings can be achieved by coating the outdoor walls with paints that have high solar reflectance (0.3-2.5µm) and high thermal emittance (4-80µm). In this presentation, the thermal performance of some paints is studied through an outdoor experiment. In a second part, the inwards conductive flux for a non-insulated...

Confined environments are indoor spaces in which the air is not renewed or very poorly renewed by fresh outdoor air (spacecraft, submarines, etc.). In these environments, indoor air quality (IAQ) is expected to be highly influenced by homogeneous and heterogeneous chemistry. This paper presents a representative example of the contribution of these...

The airflow pattern on the spectators' terrace in stadia is affected by numerous architectural factors, such as form, size, permeability, i.e. the morphology of the building. A stadium design not taking into account the prevailing environmental parameters can result in unpleasant thermal and aerodynamic environment in the stadium bowl.The present a...

To better understand the similarities and differences between moisture and volatile organic compound (VOC) diffusion through porous media, a dual chamber experimental system was developed. The diffusion and partition coefficients of moisture and selected VOCs in materials were compared. A pilot test with gypsum wallboard and oriented strand board (...

Although potentially having a significant influence on indoor air quality (IAQ), interactions between building materials and gaseous contaminants have often been neglected or crudely modelled in IAQ simulation tools. During the past 20 years, empirical source and sink models have progressively given way to physically based models; but confusion sti...

Le présent état de l'art a été établi sur la base des travaux conduits au niveau international dans tous les domaines identifiés comme nécessaires pour aborder la problématique. Cette analyse est présentée selon deux approches complémentaires : - Une analyse des phénomènes de transfert entre environnement urbain et bâtiment afin de dégager l'intera...

The design, siting and orientation of many modern poultry houses in Arab countries indicate that the principles of thermal exchange are not widely known or, if known, are too often ignored. In this paper the measures which could be used to reduce the fatal effect of the heat stress phenomenon are presented by modelling and simulating a typical poul...

The fast and uncontrolled emergence of a will to promote sustainable development in the field of building construction generates new requirements for urban development. Besides technical solutions, project managers or urban planners must take into consideration the overall impact of their project on the local and global environment as well as socia...

Confined environments are indoor spaces which are not ventilated or few ventilated due to specific use (shelters, submarines …). In such environments, homogeneous and heterogeneous chemistry are expected to play a key role in indoor air quality (IAQ). The paper presents a representative example of the contribution of these two phenomena to the prod...

In this paper a case study of building cooling-load reduction in a street canyon is studied. According to Synnefa (2005) and Levinson et Al (2006) ``cool'' paintings can be designed with a specific high reflectance and emittance in the entire solar spectrum (UV, VIS, NIR). Extensive studies showed that their surface temperatures are lower than that...

Spectators’ aerothermal comfort in stadia is affected by the stadium morphology. The morphology signifies not only the global building form, but also the dimension, the position, the porosity of the different building elements, such as the roof, the façade and the spectators’ terrace. The airflow modifying effects of these architectural parameters...

The development of air conditioning systems for summertime thermal comfort participates in an increasing proportion in the building energy demand. The objective of this study is to define the interactions between the urban microclimate, buildings and their air conditioning energy demand by the simulation of heat and mass transfer in the typical cas...

This paper describes the rehabilitation project of the Utrillo Building located in La Rochelle, France. The present project has been launched within the national frame of Urban Renovation Plan. It does not consist only of the building rehabilitation, but it aims at a real urban renovation replacing the buildings in a new urban scenario. In the pres...

The improvement of housing envelopes can play an important role to change the image of the building, to modify the use inside the dwelling, to transform the immediate surroundings of the buildings, to improve the technical and functional performance of the building and to enhance the life environment of inhabitants. In this perspective, and since 1...

The present paper aims to give an overview of the various problems, needs and solutions identified in the rehabilitation of urban building envelopes in France relatively to the important stock of social housing built during the 1950 to 1975 period. An urban case study, including urban intervention and building rehabilitation, presents briefly an on...

The total number of dwellings and apartments in France is about 25 Millions in main homes. But the building periods are closely related to the public housing policies and historical contexts. Thus, it appears that, from 1955 up to 1975, a large amount of buildings, especially in social housing, was built in mass production in order to reduce the dw...

The use of water droplet evaporation in shower towers and passive downdraft evaporative cooling needs the estimation of the time needed to completely evaporate the drops. To solve this problem, a cellular approach is proposed in which the spray is considered as a pile of rigid spheres of equal size; each sphere has multiple layers and contains a dr...