PCM-to-Air Heat Exchangers for Free Cooling Applications

Applications of PCM-to-air heat exchangers (PAHXs) were discussed in literature for free cooling application due to their latent thermal storage abilities. This paper aims to justify the generalization of a numerical model of PAHX and to compare the thermal performance of two different configurations of PAHX system. A generalized numerical model is developed and validated based on general apparent heat capacity method. The validation results show good agreement of the generalized approach in terms of averaged error with the experimental data. Model potential and limitations are discussed, and further recommendations are proposed to improve model accuracy. The paper ensures the significant potential of a PAHX ventilated façade configuration in free cooling applications

Contribution to the Thermal Renovation of Old Buildings: Numerical and Experimental Approach for Characterizing a Double Window

AbstractIn a global context of climate change and greenhouse gas emissions, the construction sector has a great potential for energy savings and environmental impact reduction. Nearly two-thirds of French buildings were built without any existing thermal regulation: thermal renovation of these buildings is a priority. However, some of these buildings are classified as “historical heritage remarkable architecture”; this strong constraint does not allow the use of traditional renovation methods. This study aims to characterize the thermal behavior of a double window. A numerical thermal model is developed taking into account the heat and mass transfer in the double window. A specific experimental platform has also been designed and built to experimentally characterize the behavior of the double window and to validate the developed numerical model. A simulation protocol was then defined and implemented in order to outline the key parameters and therefore make recommendations for double window implementation and their design.The numerical and experimental results were used to characterize the influence of the thickness of the air gap of the double window, the thermal inertia of the facade and the ventilation strategies

Numerical assessment of mechanical ventilation filtration

The improvements in living standards and air-conditioning have widely been applied, however, the health effects of indoor air pollution have been increasing, especially in the last three years with the coronavirus. To get clean air through the building, filtration is one of the most efficient strategies to optimize indoor air quality. In this regard, a comparative study was done in a classroom at ENTPE laboratory to emphasize filtration’s importance and to test the efficiency of analyzed type PM10_50. The results highlighted allows us to see the impact of control strategy on the efficiency of filtration (air conditions and ventilation systems performances). The numerical feedback has also been analyzed and the results allowed us to find an efficient filter and draw recommendations for their use

Comfort-Oriented Metamorphic House (COMETAE)

Publications Internes de l'IRISA ISSN : 2102-6327This proposal aims at challenging the existing design paradigm of residential building architecture with insights from pervasive computing, robotics, human-computer interaction and cognitive ergonomics. ICT and architecture will be holistically integrated in order to realize a radical advancement leading to metamorphic houses. Supported by ICT, domestic environments will self-adapt to the ongoing activities of inhabitants, to increase the comfort of living and optimize the use of space and energy. The same physical space will be transformed for diff erent uses, giving inhabitants the illusion of living in a bigger, more adapted and more comfortable place. The traditional tradeoff between comfort and energy conservation will also be revisited, thanks to an optimal exploitation of natural light, heat and ventilation. The realization of the targeted breakthrough will be achieved through cross-fertilization between involved disciplines and by the support of a panel of final users, architects and building engineers in the design, development and evaluation phases. COMETAE will introduce a novel approach to smart spaces research, where the space is itself an actuator of the system. Indoor environment, space and energy use will be optimized with respect to environmental factors, occupants' activities and life cycle, by orchestrating adaptive robotic building components, while ensuring occupants' safety. New coupling between inhabitants and their environment will be enabled by combining human-computer interaction and space recon guration, considering beauty of interaction and multi-user scenarios. This proposal opens the way towards a radically new use of ICT, needed to address future limitations of space and energy in the domestic environment, imposed by the ongoing and future evolutions of technology, environmental questions and socio-demographic factors

Mouvements d'air

National audienc

Numerical modelling and experimental validation of pcm-to-air heat exchangers: application of ventilated building envelopes

International audienc

Développement et évaluation numérique et expérimentale de stratégies de régulation de la ventilation hybride

Les systèmes de ventilation sont des composants essentiels à prendre en compte lors de la conception des bâtiments. En effet, alors que la ventilation a longtemps été associée à la qualité de l'air intérieur, on constate un intérêt grandissant pour la ventilation pour le confort d'été. Dans le cas des systèmes de ventilation hybride, la coexistence de deux modes de ventilation différents associée à des objectifs d'économie d'énergie nécessitent une meilleure évoluée. Notre étude vise le développement et l'évaluation sur le plan numérique et expérimental de plusieurs architectures de contrôleurs pour la gestion de la ventilation hybride. Dans un premier temps, nous effectuons un choix des paramètres, des types de contrôleurs et de la méthode d'évaluation à travers un rappel des principes fondamentaux des différents composants intervenant dans cette gestion (confort thermique, qualité de l'air, systèmes de ventilation et techniques de contrôle). Nous présentons ensuite les outils numériques (modèle thermoaéraulique HYBCELL1.0) et expérimentaux (cellule HYBCELL) développés afin d'élaborer et d'évaluer les architectures de contrôle. Une première approche de stratégies de contrôle de la ventilation hybride basées sur des contrôleurs simples pour un cas fictif montre les limites des techniques de contrôle et des méthodes d'évaluation simples. Nous nous intéressons ensuite au développement d'architectures de contrôle plus complexes (contrôleurs logiques, contrôleurs flous hiérarchiques). Pour permettre une évaluation objective sur plusieurs critères, nous avons construit deux fonctions de performance. Les performances relatives des différentes architectures sont étudiées grâce à une étude de sensibilité. Enfin, sont présentés les résultats d'une évaluation expérimentale des contrôleurs développés, en conditions hivernales.Whereas in the past, ventilation was automatically linked to indoor air quality control, there is nowadays more interest in ventilation as an energy efficient strategy to achieve thermal comfort in summer. To reach these targets and manage hybrid ventilation systems, advanced control strategies are therefore needed. In this study, we aim to develop and to assess several architectures of controllers for hybrid ventilation numerically and experimentally. In order to carry out a choice of control parameters and evaluation techniques, we first make a review of thermal comfort, indoor air quality and control principles. Then, we present the numerical tool (HYBCELL1.0) and the experimental device (HYBCELL test cell) conceived in order to develop and to assess architectures of controller for hybrid ventilation. As a first approach, simple control strategies are tested using a fictive building. More complex control strategies based on logical and hierarchical fuzzy controllers are then developed. To allow an objective evaluation of the controllers using comfort, indoor air quality, energy and stability creterias, two fitness functions were used. The relative performances of developped architectures are then studied using a sensitivity study. Finaly, the results of an experimental evaluation of the developed controllers under winter climat are presentedVILLEURBANNE-DOC'INSA LYON (692662301) / SudocSudocFranceF

Thermal performance of PCM-to-air heat exchangers in hot desert climate

International audienc

Experimental and numerical analysis of a new wind tunnel for building and mechanical ventilation components performance assessment

Aeraulic, air movement, and wind effects studies are of high importance when assessing building performances. Indeed, several studies have been conducted using wind tunnels to better understand aerodynamics inside and around buildings. The objective of this study is to accurately characterize the air velocity field inside the test chamber of a wind tunnel at different locations using the Hot-Wire-Anemometry technique and propose an experimental protocol to extend the use of wind tunnels to study mechanical ventilation systems’ performances. To this end, a first intercomparing protocol involving six hot-wire anemometers was carried out to verify the accuracy of measurements. In addition, we have developed a CFD numerical model of the wind tunnel under the Ansys Fluent environment. Several turbulence models, numerical schemes, and mesh types were studied to analyze the air velocity distribution and identify the appropriate model fitting experimental results. As a result, the CFD model uses the Quadrilateral Structured Fine Mapped mesh, Standard k−ε as a turbulence model, and MUSCL as a discretization scheme with a relative error of 5.21% to experiment values. Both wind tunnel and its numerical model are designated to establish on-demand building and ventilation components performance assessment using a hybrid approach, numerical and experimental

Heating, ventilating and cooling impacts of double windows on historic buildings in Mediterranean area

International audienc