Claude-Alain Roulet

Swiss Federal Institute of Technology in Lausanne | EPFL · Solar Energy and Building Physics Laboratory

The Scol’air-FR project is issued from the need to establish an inventory of indoor air quality conditions in primary schools of the canton of Fribourg, Switzerland. In Fribourg, the official trend is to promote mechanical ventilation systems in schools to ensure a good air quality. A properly designed, built, commissioned, and operated mechanical...

The aim of this work is to examine the thermohydric behavior of a building made of compressed stabilized earth bricks (CSEB), by testing its effectiveness in stabilizing the quality of indoor air, compared to four conventional materials. The study is carried out using TRNSYS-COMIS software with its Buffer Storage Humidity Model for three types of c...

This study tested the effectiveness of some natural ventilation basic configurations for the thermal comfort of occupants in different local climates in Algeria. Due to the diverse Algerian climate, the study was performed during the mid-season period that includes three months of May, September, and October and the summer that includes the months...

The building should be designed and constructed first to bring a good indoor environment to its occupants. This chapter addresses thermal comfort and passive means to improve ensure it. These are thermal insulation and inertia, solar collecting area and their solar protections, natural ventilation and combinations of them allowing passive solar hea...

This study tested the effectiveness of some natural ventilation basic configurations for the thermal comfort of occupants in different local climates in Algeria. Due to the diverse Algerian climate, the study was performed during the mid-season period that includes three months of May, September, and October and the summer that includes the months...

Sustainable construction has become a real issue in Algeria and in the whole world. The compressed and cement stabilized earth blocks remain among the materials that contribute to a healthy, ecological and sustainable environment, as well as a source of interior comfort. In this work, an experimental investigation is performed on hygrothermal chara...

Stakeholders in the design, construction and use of a building have different objectives (profitability, prestige, comfort, well-being, sustainability, environmental impact, etc.). In fact, these issues-which are not necessarily contradictory-must be all considered from the early beginning of a project, then during the design, construction and use...

Stakeholders in the design, construction and use of a building have different objectives (profitability, prestige, comfort, well-being, sustainability, environmental impact, etc.). In fact, these issues - which are not necessarily contradictory - must be all considered by the architect from the early beginning of a project, then during the design,...

L'exposé, malgré son titre provocant, montre tout de même comment réussir et exploiter un bâtiment où il fait bon vivre ! Les progrès de la physique du bâtiment pendant ces 50 dernières années permettent actuellement de concevoir et de construire – voire rénover-des locaux confortables et à faible impact environnemental. Après une définition du con...

The research project was initiated in 1993 by the Commission of European Communities. Its general objective was to improve the knowledge on indoor air quality in relationship with energy consumption in large office buildings. Seven countries of the European Community and three EFTA countries participate to this project. To gain knowledge, at least...

The aim of this article is to study by numerical simulation with the TRNSYS-COMIS software, the thermo-aeraulic behavior of a traditional house with a horizontal opening in the central space of the house, and in the city of Kenadsa (southwestern Algeria, hot dry climate). In these regions with hot, dry climates, traditional architecture was develop...

This manual intends to help newcomers in a laboratory to measure the main characteristics of thermal insulation materials, i.e. thickness, density and thermal conductivity. Such materials are first presented, together with their applications in the building envelope. The instruments used to measure the thermal conductivity are described, followed b...

This paper addresses the effect of the type of habitat on thermal comfort and energy requirements for heating and cooling s for 7 Algerian cities located in different climatic zones of the country. Our choice is focused on four buildings: two traditional houses: a home with overhead ceiling opening (covered patio), an open patio house; and two repr...

Nous passons le plus clair de notre temps dans les bâtiments, qui doivent donc être confor-tables et sains. Dans une optique de développement durable, cet objectif doit être atteint en utilisant de l’énergie exclusivement renouvelable, ce qui implique une limitation des besoins. Une conception basée sur les mesures passives, adaptée au climat et à...

The ventilation of buildings is used to maintain indoor air quality and thermal comfort. The purpose of ventilation is to eliminate airborne contaminants, which are generated both by human activity and by the building itself. Most mechanical ventilation systems are designed to fulfil this condition. The adaptive comfort model only provides design r...

In order to ensure good indoor air quality in buildings at reasonable energy and financial cost, ventilation performance should be checked to detect potential problems early enough, and to optimise the overall performance of the ventilation system. This includes appropriate airflow rates, negligible leakage and shortcuts, high ventilation efficienc...

The HOPE European research project aimed to look at a possible relationship between the energy performance of a building and the well-being (health and comfort) of their occupants. An interdisciplinary survey resulted in guidelines to increase the number of energy-efficient buildings that are at the same time healthy and comfortable. These guidelin...

Concevoir et réaliser un bâtiment à la fois sain, confortable, à basse consommation d’énergie et à faible impact sur l’environnement? Oui, c’est possible! Claude Alain Roulet, ingénieur spécialiste du domaine et Professeur honoraire à l'EPFL, dévoile dans son nouveau livre "ECO-CONFORT - Pour une maison saine et à basse consommation 'énergie" l’ens...

Un bâtiment construit doit être avant tout confortable et sain. C'est en fait sa raison d'être. Il doit protéger les occupants de l'environnement extérieur, assurer un climat agréable à l'intérieur et fournir des services tels que communications et transports. L'objectif principal de cet ouvrage est de faciliter l'expression et la création artistiq...

Environmental conditions play a crucial role in mite growth, and optimal environmental control is key in the prevention of airway inflammation in chronic allergic rhinoconjunctivitis or asthma. To evaluate the relationship between building energy performance and indoor mite allergen concentration in a cross-sectional study. Major allergen concentra...

Ces notes de cours présentent le conditions de confort thermique, aéraulique, acoustique et visuel et les moyens de les réaliser en priorité par des mesures architecturales et constructives..

Afin de promouvoir l'efficacité énergétique dans la construction, la SIA va publier prochainement une méthode standard pour la certification du comportement énergétique des bâtiments. L’objectif est de proposer un outil qui permette de connaitre la consommation d’énergie annuelle de chaque bâtiment. Cet outil sera présenté sous la forme d’un certif...

Afin de promouvoir l'efficacité énergétique dans la construction, la SIA va pu-blier prochainement une méthode standard pour la certification du comportement énergétique des bâtiments. L’objectif est de proposer un outil qui permette de connaitre la consommation d’énergie annuelle de chaque bâtiment. Cet outil sera présenté sous la forme d’un certi...

Afin de promouvoir l'efficacité énergétique dans la construction, la SIA va pu-blier prochainement une méthode standard pour la certification du comportement énergétique des bâtiments. L’objectif est de proposer un outil qui permette de connaitre la consommation d’énergie annuelle de chaque bâtiment. Cet outil sera présenté sous la forme d’un certi...

Energy efficiency in buildings requires, among other things, that ventilation be appropriately dimensioned: too much ventilation wastes energy, and insufficient ventilation leads to poor indoor air quality and low comfort. Studies have shown that ventilation systems seldom function according to their commissioned design. This key handbook explains...

Le bâtiment est (ou en tous cas devrait être) conçu et construit avant tout pour être confortable et sain. L'économie d'énergie n'est pas un but en soi, car si c'était le cas, le plus efficace serait de ne pas construire le bâtiment. Dans les bâtiments, on utilise de l'énergie pour améliorer le confort et la qualité de l'environnement intérieur (ch...

The European Directive on Building Energy Performance aims "to promote the improvement of the energy performance of buildings within the Community, taking into account outdoor climatic and local conditions, as well as indoor climate requirements and cost-effectiveness." Therefore, it requires several different measures to achieve sustainable and ra...

This chapter of a book published by Taylor and Francis in 2007 (Ventilation Systems, Design and Performance) addresses the human requirements for an acceptable indoor air quality and thermal comfort,

A qualidade do ar interior (QAI) requer arejamento. Oependendo do clima, a energia perde-se corn o ar que sai ou é exfiltrado e também pode ser utilizada para condicionar ar nova e movimentar o ar num sistema de ventilaçao mecânica. Depois da primeira crise do preço do petr61eo (1973), foram tomadas precipitadamente medidas de poupança de energia,...

In order to promote the reduction of the energy use in buildings, the Swiss society of Architects and Engineers (SIA) decided to publish a standard methodology for building energy certification. According to a sustainable development strategy, this method also evaluates the emissions of greenhouse gases related to energy use. Both calculations and...

This chapter of a book ( Ventilation Systems, Design and Performance9 edited by Azim Awbi and published by Taylor and Francis in 2007 describes the various types of ventilation systems, their components and control methods. Methods for measuring the airflow rates in the mechanical ventiolation systems are also described, together with actual exampl...

The causes of SBS are likely multiple and may come from building fabric, activity, building systems, management and even general mood. Several chemicals are known to cause all the SBS symptoms if the exposure is strong enough. However, SBS may appear even when the concentrations of dangerous chemicals in indoor air are much smaller than limits at w...

Ventilation systems often host bacteria and fungi that may be dangerous for the health of exposed people. Essential oils are one means among others to prevent microbial development. Used as a basis for many traditional therapies, these odorant plant extracts have been studied extensively in the medical domain and their effectiveness in the treatmen...

Dans les pays industrialisés, les bâtiments consomment une partie importante de l'énergie utilisée par la société et, en conséquence, ils sont source d'une partie non négligeable de la pollution. Cette énergie est utilisée pour de nombreux usages, notamment:  le chauffage et/ou le refroidissement, pour assurer un climat intérieur confortable  la...

Energy is used in buildings to improve well being of occupants. Discomfort generally results from lack of energy. However, is well being better in buildings using much energy? In other words, are low energy buildings uncomfortable? Within the European research project HOPE, 97 apartment buildings and 67 office buildings-of which approximately 50% a...

In order to comply with sustainable development policy, the minimum that buildings should achieve are a healthy, comfortable and energy-efficient environment. Criteria for individually assessing each of the many criteria are known: the occupant's perceived health; the provided thermal, visual and acoustical comfort; and the indoor air quality and e...

Within the European research project Health Optimisation Protocol for Energy-efficient Building (HOPE), 96 apartment buildings and 64 office buildings (of which approximately 75% have been designed to be energy-efficient) were investigated. The building characteristics were assessed according to a checklist during a walk-through survey. Occupant qu...

Methods to measure airflow rates using tracer gas in single air-handling units are well known. In some buildings, however, in particular in Singapore, rooms are often ventilated with two or more units and present large recirculation rates. Large recirculation ratios homogenize the concentrations, so concentrations in supply and extract ducts are cl...

A method is proposed to assess the natural ventilation potential by taking into account the most comprehensive set of factors involved in natural ventilation. These factors are either driving forces, such as wind pressure and stack effect, or constraints, like noise pollution and atmospheric pollution. The process considers these factors in an ordi...

This study compares the characteristics of volatile organic compounds (VOCs) and the associated factors affecting them within European (EU) and Singapore buildings. Generally, concentrations of target VOCs determined in the two types of buildings were within health and comfort guidelines. This study found that concentrations of 2-methylpentane and...

The Sick Building Syndrom (SBS) is often supposed to be an IAQ problem. In fact, it seems much more complex, since SBS may be present even when IAQ standards are met.

Methods to measure airflow rates using tracer gas in single air handling units are well known. In some buildings however, in particular in Singapore, rooms are often ventilated with two or more units and present large recirculation rates. Large recirculation ratio homogenise the concentrations, so concentrations in supply and extract ducts are clos...

Within the European research project HOPE, 97 apartmentbuildings and 67 office buildings were investigated using checklists addressing the building characteristics and self-administered questionnaires to the occupants asking their perceived comfort (thermal visual, acoustical and indoor air quality) and health(sick building syndrome symptoms and al...

ABSTRACT : The Energy Performance of Buildings Directive (EPBD) requires EU member states to establish a methodology for calculating the energy performance of buildings within a framework that includes the effect of active and passive solar systems as well as other characteristics of buildings and their installed energy systems. Member states must...

Buildings should be comfortable and healthy. They are a shelter for their occupants and should not be a source of problems. The architect widely influences the indoor environment quality by his design,. Ensuring a good indoor environment through appropriate architectural measures is one of the stakes of sustainable architecture. For that purpose an...

The Energy Performance of Buildings Directive (EPBD) requires EU member states to establish a methodology for calculating the energy performance of buildings within a framework that includes the effect of active and passive solar systems as well as other characteristics of buildings and their installed energy systems. Member states must also implem...

Within the European research project HOPE, 97 apartment buildings and 67 office buildings - of which approximately 75% have been designed to be energy-efficient, and half of them are indeed - were investigated using checklists addressing the building characteristics and ques-tionnaires to the occupants asking their perceived comfort (thermal visual...

One of the aims of the HOPE project is to develop a method to assess healthiness and energy efficiency of buildings and strategies to optimise their performance towards health and energy efficiency. In this project, a building is defined "Healthy and Energy Efficient" if: it does not cause or aggravate illnesses of the building occupants; it assure...

The application of natural ventilation is more difficult in urban than in rural environment, especially in street canyons due to reduced wind velocity, urban heat island, noise and pollution, which are considered to be important barriers to the application of natural ventilation. The wind, temperature, noise attenuation and outdoor-indoor pollution...

The design of a building should provide the flow paths needed for natural ventilation. Therefore, the decision to apply natural ventilation should be taken early in the building design process, when little information is available for airflow estimation. To deal with this lack of data, a semi-qualitative method to assess the potential of an urban s...

The architectural decisions for building that use natural ventilation should be taken in the initial stages of design when little information is avail- able. A new approach is to compare the poten- tial natural ventilation of known buildings in a new site and to adapt the design of the known example. The potential of natural ventilation may be chan...

The design of a building should provide the flow paths needed for natural ventilation. Therefore, the decision to apply natural ventilation should be taken early in the building design process, when little information is available for airflow estimation. To deal with this lack of data, a semi-qualitative method to assess the potential of an urban s...

A method is proposed to assess the natural ventilation potential by taking into account the most comprehensive set of factors involved in natural ventilation. These factors are either driving forces, such as wind pressure and stack effect, or constraints, like noise pollution and atmospheric pollution. The process considers these factors in an ordi...

Within the European research project HOPE, 64 office buildings were audited regarding in-door environment quality and building characteristics. Of those buildings, two groups are se-lected: 21 buildings with low prevalence of the sick building syndrome, and 21 buildings with the largest prevalence. However, none of these buildings was considered a...

The main airflow and contaminant paths or the spatial distribution of the age of air (or contaminant) in a room are of great interest in estimating venrilation efficiency. A simple meusurement method is presented which consists of injecting one or more tracer gases at locations of interest and analysing the concentration at several other locations,...

The European AIRLESS programme was started to identify the pollution sources in air-handling units, to characterise these sources using measurement protocols developed on purpose, to propose measures to avoid or eliminate this pollution, and to assess the effect of such measures on the energy use. This paper addresses the energy use in air-handling...

Le bâtiment est construit pour être habité et donc pour offrir à ses occupants un environnement intérieur agréable et sain. Les conditions de confort thermique, acoustique, visuel ainsi que les exigences relatives à la qualité de l'air doivent donc être toutes satisfaites. Une bonne manière d'y parvenir est de concevoir le bâtiment de manière qu'il...

From 1998 to 2000, a European project named AIRLESS was conducted by 12 institutes, universities and companies from seven European countries. The objective was to develop strategies, principles and protocols to improve and control the performance of HVAC-systems and its components for incorporation in codes and guidelines. The first step was to def...

This study highlights the presence of dominant source/s of several VOCs and their geographical similarities and differences within EU and Singapore buildings. Concentrations and emission rates of 2-methylpentane and heptane are higher in EU buildings as compared to the ones in Singapore. Also, lower alkanes are observed to be higher in levels in EU...

Tracer gases are often used to assess airflow rates in air handling units. Published methods are mostly designed for units with recirculation ratios lower than those commonly found in Sin-gapore and other tropical countries. Large recirculation ratio homogenise the concentrations, so that concentrations in supply and extract ducts are close to each...

Many studies have shown that ventilation systems often host bacteria and fungi that may be dangerous for the health of exposed people. This problem may be particularly acute in hospi-tals, where exposed people are more sensitive. The paper presents the methodology developed to study the effectiveness of some plant's extract, the essential oils to h...

In January 2002, a new European project named HOPE (Health Optimisation Protocol for Energy-efficient Buildings) started with 14 participants from nine European countries. The final goal of the project is to provide the means to increase the number of energy-efficient buildings, i.e. buildings that are at the same time healthy and low energy users....

Many studies have shown that ventilation systems often host bacteria and fungi that may be dangerous for the health of exposed people. This problem may be particularly acute in hospitals , where exposed people are more sensitive. The paper presents the first results of the methodology developed to study the effectiveness of some plant's extract, th...