Search

Electrochromic glazing can involve substantial energy consumption in the building sector with their optical properties driven either by various occupant needs or environmental conditions. This paper presents comparison of ten different control strategies developed for such a glazing system in terms of specific energy consumption of a PASSYS test cell where the glazing was installed. The control strategies include scheduled ON–OFF controllers, a PID and advanced fuzzy controllers which were developed using experimental data. We used energy simulation to analyse the annual heating, cooling and lighting demands investigating the influence of each control strategy to the thermal behaviour of the building.

This paper presents a state-of-the-art review of the thermal behaviour of the diffusive building envelope, through which slow and nearly uniform air flows. With the airflow through the envelope, it will exchange heat with solid parts, thus changing the thermal performance of the envelope. The fundamental heat exchange in the air cavities of the envelope is first investigated. Next, the study focuses on the airflow and heat transfer in the porous building materials, in order to assess airflow impact on the thermal performance of the dynamic insulation. The influence of moisture, especially possible phase change, is also discussed. The investigation shows that heat exchange in the envelope will have an impact on the energy consumption of the building. Meanwhile, much work is needed concerning engineering implementation; for example, to provide the suitable analytical methods and to avoid possible condensation.

The project BESTFACADE, sponsored by the Energy Intelligent Europe programme of the European Union, and led by MCE-Anlagenbau, Austria, accumulated the state of the art of double skin facades (DSFs) in seven European countries (Austria, Belgium, France, Germany, Greece, Portugal and Sweden). Twenty-eight facades of different buildings in all partner countries of BESTFACADE have been analysed for the aspects, types of facade in different countries, DSFs in different climatic regions of Europe, existing simulations and measurements, thermal behaviour, indoor air quality, comfort, user acceptance, energy demand and consumptions, control strategies, integrated building technology, cost (investment, maintenance and operation), resource conservation, environmental impact, comparison to conventional glass facades (CGFs), integration of renewable energy sources into DSFs, as well as non-energy related issues, such as, acoustics, aesthetics, fire protection, moisture, corrosion, durability, maintenance an...

The potential of controlling techniques for an electrochromic device is investigated in a systematic way, using both experimental and theoretical tools. Concerning the theoretical part a model was developed in the TRNSYS environment and validated against experimental data. These data were collected from experiments, which were carried out in a PASSYS test cell with a movable wall. Having established a good model performance several cases of window types (such as a 4 mm clear window and a low-e double glazing) and controlling strategies for the electrochromic device are simulated. Obtained results from the series of simulations were compared in terms of the heating and cooling loads of the test cell for each case. It was found that the development of a scheduled control strategy for the electrochromic glazing is better in terms of cooling loads. Finally, a more sophisticated control strategy was examined based on the adaptive fuzzy approach.

This paper presents the development and testing of a multi objective fuzzy controller. It is dedicated to the control of thermal comfort and indoor air quality while minimising energy consumption and reducing instabilities are other constraints for this controller. After a brief introduction on the difficult task of indoor climate control, the test cell and its corresponding model is described in the second section. The model has been developed within TRNSYS. Section 3 describes the architecture of the fuzzy controller applied to these control objectives in the test cell. A hierarchical architecture has finally been selected since it is a very flexible architecture and it results in reducing the total number of fuzzy rules. The rule optimisation technique, based on genetic algorithms is also presented in the third section. Simulation results are finally presented. They prove that, after optimisation, the fuzzy controller greatly outperforms a typical ON-OFF controller on all control criteria. Energy consu...

Highly-glazed spaces are attractive in many ways (solar heating, aesthetics, etc.), however, their thermal behaviour remains difficult to predict. In such spaces, the assumptions or methods generally used in building thermal simulation tools — e.g. homogeneous air temperature in the room, simplified calculations of radiative heat transfer between walls, absence of airflow modelling within the room — do not seem appropriate. We have developed a new model (AIRGLAZE) to improve the prediction of the thermal behaviour of large highly-glazed spaces. It consists of an envelope module to calculate conductive and radiative heat transfer in the building envelope. It is coupled with a zonal airflow model to predict air motion within the room. Particular attention is paid to sun patch modelling and the internal distribution of shortwave and longwave radiation within the building; direct retransmission, reflection to the outside, and transmission to other zones of the building are taken into account. The results of AIRGLAZE are compared with measurement data from two experimental test cells: the IEA Annex 26 experimental atrium, and a test cell at ENTPE. Compared to the one-air-node approach, the zonal method significantly reduces the mean discrepancy with measurement data during stratified conditions (from 3.9°C down to 0.4°C for the Annex 26 atrium). In general, experimental and numerical results tally well in both cases.

This paper is dedicated to the numerical study of natural ventilation in a room through a large external opening using the CFD code Fluent. Bidimensional numerical simulations are performed for wind speeds up to 5.55 m·s−1 (20 km·h−1). We propose a two-step solution procedure with grid refinement. When combined with appropriate thermal boundary conditions, this technique appears very efficient at limiting local convergence problems. Through an analysis of the flow pattern in the cavity, we qualitatively explain those results and define a critical Archimedes number. Calculated air change rates are compared to values deduced from empirical correlations of the literature. Agreement is in general poor, which can be explained by the differences between the conditions of our simulations and those of the experiments that lead to those correlations. However, from our simulations, we derived very clear correlations between the air change coefficient and the Archimedes number. In the last part, our results are compared with published data from two experiments. Agreement, in terms of air change coefficient, is within 26 % on average with the Porto test cell data which is closest to our numerical conditions. One should be careful about the transposition of our results to different ventilation scenarios.

L’evolution de l’humanite est fortement liee au developpement des ressources energetiques, traduite par une augmentation quasi exponentielle de la consommation energetique mondiale, celle-ci dependante de la croissance du PIB jusqu’a la premiere crise petroliere en 1974. Depuis le debut des annees 1980, les contraintes liees a I’utilisation rationnelle de l’energie ont conduit a l’optimisation des systemes energetiques. A cela s’ajoutent les exigences ecologiques et de developpement durable apparues au debut de la decennie 1990. Le domaine du genie energetique est donc un composant important du champ scientifique de l’ingenieur. Le rencherissement du cout de l’energie, la complexite technique croissante et la multiplication des problemes instationnaires ont en effet donne une importance particuliere au traitement de la thermique du bâtiment. Faut-il rappeler que le secteur du bâtiment est le plus gros consommateur d’energie en France avec 45 %, en moyenne, de la consommation totale. L’objectif de la rubrique est de contribuer a l’analyse des phenomenes et aux choix du formalisme mathematique adapte, domaine d’excellence de l’ingenieur.

This paper is not a technical paper but, instead, focuses on the methods by which information on recent advances in ventilation technology and systems may be transferred to engineers. This is important because it enables the application of these innovations in the design and maintenance of buildings. In this context, the paper describes the educational material developed by the European project Vent DisCourse. It consists of material specifically written to facilitate distance learning postgraduate study in the area of energy efficient ventilation for buildings. Vent Discourse is mainly aimed at European building professionals to facilitate the implementation of the energy performance in buildings directive (EPBD). The method of development was based on a review and evaluation of educational distance learning methods for the target audience and their application to building ventilation. The contents were based on a study concerning the collection, evaluation and classification of existing informat...

Traditional wood buildings in France and in Madagascar use abundant local forest resources in architecture. Woodcan be considered as renewable and natural material when coming from sustainably managed forest. Using wood in construction contributes significantly in controlling the atmospheric carbon cycle and the emission of greenhouse gas. This study presents the main physical characteristics of wood materials and building systems showing the influence of wood coating on indoor environment. Hygrothermal phenomena across the living space are characterized and presented in this work : the presence of water in the wood, the behavior of equilibrium moisture, heat transfer and mass transfer, the physical parameters of wood material and physical parameters of indoor environment. Thermal comfort is similarly characterised. This work contributes knowledge on the evaluation of interactions between thermal comfort, indoor air and wood coating by means of in situ and laboratory measurements and numerical model simulations., Les constructions traditionnelles en bois en France et à Madagascar témoignent de l’utilisation ancienne d’abondantes ressources forestières locales. Le bois peut être considéré comme un matériau naturel et renouvelable dans la mesure où les ressources forestières sont gérées durablement. L’utilisation du bois dans la construction contribue largement à la maîtrise du cycle du carbone atmosphérique et à la limitation des émissions de gaz à effet de serre. Ce travail présente les principales caractéristiques physiques du matériau bois et des systèmes constructifs associés, montrant l’importance et l’influence du revêtement en bois sur l’environnement intérieur des habitations. La caractérisation des phénomènes hygrothermiques à l’échelle de la pièce d’habitation a été détaillée : présence d’eau dans le bois, comportement de l’équilibre hygroscopique, transfert thermique et transfert de masse, les paramètres physiques du bois et d’une ambiance intérieure. Enfin, ce travail apporte des connaissances sur l’évaluation des interactions entre le confort thermique, l’ambiance intérieure et le revêtement en bois, grâce à des campagnes de mesure in situ, à des mesures en laboratoire et à des modélisations de scénarios numériques.

Traditional wood buildings in France and in Madagascar use abundant local forest resources in architecture. Woodcan be considered as renewable and natural material when coming from sustainably managed forest. Using wood in construction contributes significantly in controlling the atmospheric carbon cycle and the emission of greenhouse gas. This study presents the main physical characteristics of wood materials and building systems showing the influence of wood coating on indoor environment. Hygrothermal phenomena across the living space are characterized and presented in this work : the presence of water in the wood, the behavior of equilibrium moisture, heat transfer and mass transfer, the physical parameters of wood material and physical parameters of indoor environment. Thermal comfort is similarly characterised. This work contributes knowledge on the evaluation of interactions between thermal comfort, indoor air and wood coating by means of in situ and laboratory measurements and numerical model simulations., Les constructions traditionnelles en bois en France et à Madagascar témoignent de l’utilisation ancienne d’abondantes ressources forestières locales. Le bois peut être considéré comme un matériau naturel et renouvelable dans la mesure où les ressources forestières sont gérées durablement. L’utilisation du bois dans la construction contribue largement à la maîtrise du cycle du carbone atmosphérique et à la limitation des émissions de gaz à effet de serre. Ce travail présente les principales caractéristiques physiques du matériau bois et des systèmes constructifs associés, montrant l’importance et l’influence du revêtement en bois sur l’environnement intérieur des habitations. La caractérisation des phénomènes hygrothermiques à l’échelle de la pièce d’habitation a été détaillée : présence d’eau dans le bois, comportement de l’équilibre hygroscopique, transfert thermique et transfert de masse, les paramètres physiques du bois et d’une ambiance intérieure. Enfin, ce travail apporte des connaissances sur l’évaluation des interactions entre le confort thermique, l’ambiance intérieure et le revêtement en bois, grâce à des campagnes de mesure in situ, à des mesures en laboratoire et à des modélisations de scénarios numériques.