26 research outputs found
Towards New Metrics for the Characterisation of the Dynamic Performance of Adaptive Façade Systems
No full textTraditional façade characterisation metrics such as U-value and g-value are of limited value in the design process of buildings with adaptive façades. This issue is particularly important for adaptive façade components that have the capability of controlling thermal energy storage in the construction thermal mass. Building performance simulations can help to analyse the performance of buildings with adaptive façades, but such studies usually only provide information about the energy and comfort performance at room level. Consequently, there is a need for development and testing of new façade-level performance metrics that can be used to compare the performance of different adaptive façade components. This paper presents experiences and lessons learned from four European R&D projects that have introduced novel metrics to capture the dynamic performance of adaptive opaque façades. Characteristics of the different metrics are described, and their similarities and differences are compared and contrasted. The paper highlights the main benefits of metrics that can capture dynamic effects, and concludes by providing directions for future work.publishedVersionThis work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. Author(s) hold their copyright without restrictions
Dataset of the EnergyPlus model used in the assessment of natural ventilation potential through building simulation
No full textInternational audienceThe data set compiled in this file refers to the Multizone EnergyPlus model, used in the investigations of the research article entitled "Natural ventilation potential from weather analyses and building simulation". The technical information regarding the model has been grouped into tables, which include: the general simulation settings, the properties of the building materials, the Airflow Network opening settings used in the annual investigation, in addition to the controls established in the Energy Management System (EMS) for hybrid ventilation system operation. The user behaviour, regarding the living and bedrooms occupancy schedule, is also presented in a graph. This data set is made available to the public to clarify details of the EnergyPlus model and how the hybrid operation was defined. In this way, other researchers can perform an extended analysis of the information
CONTRIBUTION EXPERIMENTALE ET NUMERIQUE A L'ETUDE DU DEPOT DES PARTICULES FINES DANS LES CAVITES VENTILEES
No full textOur contribution to particle pollution studies brings at the same time an experimental and a numerical complement to the existing knowledge on indoor air quality in buildings. At the beginning we made a state of art of previous studies on fine particle dispersion and deposition in ventilated cavities. Our experimental studies were dedicated to carrying out measurements on particle deposition in two test chambers in 1 to 4 size scale relation. Our contribution highlighted the dispersion of bibliographic results and the comparison difficulty between results coming from different scale chambers. In each case, we studied simultaneously the particle deposition in function of ventilation strategy and of air change rate. During a more detailed numerical analysis, first we determined the fluid flow pattern and then particle dispersion and deposition in the ventilated cavity. At the beginning we used a Lagrangian numerical code developed in our laboratory where we integrated Brownian diffusion effects, but this approach becomes rapidly too expensive thus ineffective for simulations concerning particles smaller than 0.5 µm diameter. For this reason we tested an Eulerian approach which seemed to be more adapted for submicron sized particles. In fact, the calculated values in comparison with measured ones prove a better performance of the Eulerian method for this particle size interval.Notre contribution à l'étude des polluants particulaires apporte un complément à la fois expérimental et numérique à la connaissance existante sur la qualité de l'air intérieur dans les locaux ventilés. Dans un premier temps, nous avons réalisé un état de l'art des études existantes sur la dispersion et le dépôt des particules fines dans les cavités ventilées. Notre contribution expérimentale a été dédiée à la réalisation d'expérimentations sur le dépôt des particules dans deux cellules de rapport d'échelle 1 à 4. Nos travaux mettent en évidence la dispersion des résultats issus de la bibliographie et la difficulté de comparer des résultats issus de cellules de tailles différentes. Dans chaque cas nous avons étudié le dépôt, en fonction à la fois de la configuration de ventilation et du taux de renouvellement d'air. Au cours d'une analyse numérique plus détaillée, nous avons déterminé d'abord le mouvement de la phase fluide puis la dispersion et le dépôt des particules fines dans des cavités ventilées. Dans un premier temps, nous avons utilisé une méthode lagrangienne développée au laboratoire où nous avons intégré les effets de la diffusion brownienne, mais cette approche devient rapidement trop onéreuse et donc inopérante pour des particules de taille inférieure à 0,5 micromètres. C'est pour cette raison que nous avons testé par la suite une approche eulérienne qui paraît mieux adaptée pour les particules submicroniques. En effet, la comparaison des valeurs calculées avec celles mesurées dans les mêmes configurations souligne les bonnes performances de la méthode eulérienne pour cette taille de particule
Identification of Envelope Hygrothermal Properties Based on In-situ Sensor Measurements and Stochastic Inverse Methods
No full textAbstractThe present paper investigates the performance of gradient-free inversion methods applied to the characterisation of hygrothermal properties of building materials. Two classes of techniques were implemented to solve the inverse problem of envelope parameter identification: the Covariance Matrix Adaptation evolution strategy, and Bayesian inference. The comparison was made on the basis of a numerical benchmark, which showed that such advanced characterisation techniques can learn from incomplete or noisy data and provide reliable material characteristics, given sufficient sensor measurements. A possible application is the improvement of traditional experimental techniques for hygrothermal characterisation in labs
Study of Two Hemp Concrete Walls in Real Weather Conditions
No full textAbstractThe use of bio-based materials in construction is significantly improving. One of the bio-based materials is hemp concrete which is a composite obtained by mixing a binder and the non-fibrous part of hemp, called shiv. This specific hemp concrete developed by Vicat is made with Prompt Natural Cement (PNC) as binder. In situ hygro-thermal performance assessment of this material was performed in this paper. For this both simulation and experimental measurements are conducted in parallel. In the experimental study two PASSYS test facilities are used. They are parallelepiped test cells around 30 m3 volume each. One test wall is built with the interesting façade while the five other walls are highly insulated and are non-tested walls. Test walls are subject to weather solicitations outside and hydrothermal regulation inside. The two test cells are next to each other, and the hempcrete wall is south oriented. The only difference between cells is the external coating in order to analyze the coating effect on moisture transfer: one cell is supplied with traditional hemp lime render and the other one with cement based render. In parallel, 2D numerical simulation of hygrothermal behavior of the wall was carried out using a coupled heat and moisture transport model with boundary condition from the monitored data (outside weather conditions and inside regulation). Results show a good agreement between measured and simulated data
Développement d’un procédé pour l’épuration de l’air intérieur par couplage de la décharge couronne et de l’adsorption
No full textInternational audienc
Using CFD to evaluate natural ventilation through a 3D parametric modeling approach
No full textPredicting building air change rates is a challenge for designers seeking to deal with natural ventilation, a more and more popular passive strategy. Among the methods available for this task, computational fluid dynamics (CFD) appears the most compelling, in ascending use. However, CFD simulations require a range of settings and skills that inhibit its wide application. With the primary goal of providing a pragmatic CFD application to promote wind-driven ventilation assessments at the design phase, this paper presents a study that investigates natural ventilation integrating 3D parametric modeling and CFD. From pre- to post-processing, the workflow addresses all simulation steps: geometry and weather definition, including incident wind directions, a model set up, control, results’ edition, and visualization. Both indoor air velocities and air change rates (ACH) were calculated within the procedure, which used a test house and air measurements as a reference. The study explores alternatives in the 3D design platform’s frame to display and compute ACH and parametrically generate surfaces where air velocities are computed. The paper also discusses the effectiveness of the reference building’s natural ventilation by analyzing the CFD outputs. The proposed approach assists the practical use of CFD by designers, providing detailed information about the numerical model, as well as enabling the means to generate the cases, visualize, and post-process the results
Non-Thermal Plasma for indoor air treatment: Toluene degradation in a corona discharge at ppbv levels
No full textInternational audienc
Transparent siloxane-based polyolefin vitrimer and its use as encapsulant for recyclable photovoltaic modules
No full textInternational audiencePhotovoltaic (PV) modules are one of the core future solutions for producing large amounts of renewable energy to overcome the ongoing climate crisis. While PV modules use extensively critical materials such as monocrystalline silicon and silver, their recyclability is still poorly addressed, and the few existing processes are limited by their recovery yields and their environmental impacts. To cope with this recyclability issues, developing materials enabling adequate module properties while guaranteeing easy dismantling ability appear as mandatory to promote a wider use of PV modules as energy production mean. In this study, a new transparent vitrimer polyolefin based on siloxane bonds exchange was prepared through melt grafting. Grafting efficiency was evaluated using FTIR analyses and the materials were characterized through thermal analyses, tensile testing, dynamical mechanical analyses and creep. The vitrimer showed high transparency and reversible adhesion onto glass through a simple localized heating process. Vitrimer encapsulants based PV modules were prepared and showed promising dismantling ability, paving the way for recyclable vitrimer encapsulant based PV modules
Using CFD to Evaluate Natural Ventilation through a 3D Parametric Modeling Approach
No full textPredicting building air change rates is a challenge for designers seeking to deal with natural ventilation, a more and more popular passive strategy. Among the methods available for this task, computational fluid dynamics (CFD) appears the most compelling, in ascending use. However, CFD simulations require a range of settings and skills that inhibit its wide application. With the primary goal of providing a pragmatic CFD application to promote wind-driven ventilation assessments at the design phase, this paper presents a study that investigates natural ventilation integrating 3D parametric modeling and CFD. From pre- to post-processing, the workflow addresses all simulation steps: geometry and weather definition, including incident wind directions, a model set up, control, results’ edition, and visualization. Both indoor air velocities and air change rates (ACH) were calculated within the procedure, which used a test house and air measurements as a reference. The study explores alternatives in the 3D design platform’s frame to display and compute ACH and parametrically generate surfaces where air velocities are computed. The paper also discusses the effectiveness of the reference building’s natural ventilation by analyzing the CFD outputs. The proposed approach assists the practical use of CFD by designers, providing detailed information about the numerical model, as well as enabling the means to generate the cases, visualize, and post-process the results
