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2. Numerical evaluation of the thermal performances of roof-mounted radiant barriers

Author

Miranville, Frédéric, Boyer, Harry, Lucas, Franck, and Johan, Seriacaroupin

Subjects
Physics - Instrumentation and Detectors
Abstract

This paper deals with the thermal performances of roof-mounted radiant barriers. Using dynamic simulations of a mathematical model of a whole test cell including a radiant barrier installed between the roof top and the ceiling, the thermal performance of the roof is calculated. The mean method is more particularly used to assess the thermal resistance of the building component and lead to a value which is compared to the one obtained for a mass insulation product such as polyurethane foam. On a further stage, the thermal mathematical model is replaced by a thermo-aeraulic model which is used to evaluate the thermal resistance of the roof as a function of the airflow rate. The results shows a better performance of the roof in this new configuration, which is widely used in practice. Finally, the mathematical relation between the thermal resistance and the airflow rate is proposed.

Published
2014

3. Impact of the atmospheric boundary layer profile on the ventilation of a cubic building with two large opposite openings

Author

Bastide, Alain, Lucas, Franck, and Boyer, Harry

Subjects
Physics - Fluid Dynamics
Abstract

The aim of this paper is to show the influence of the atmospheric boundary layer profile on the distribution of velocity in a building having two large openings. The knowledge of the flow form inside a building is useful to define a thermal environment favourable with thermal comfort and good air quality. In computational fluid dynamics, several profiles of atmospheric boundary layer can be used like logarithmic profiles or power profiles. This paper shows the impact of these profiles on the indoor airflow. Non-ventilated or ventilated parts of room are found. They show respectively ineffective ventilation and effective ventilation. A qualitative and global approach allows to observe the flows in a cubic building and to show the influence of each profile according to the external ground roughness and the incidence angle of the wind. Some zones, where occupants move, are named volumes of life. Ventilation is there observed using traditional tools in order to analyze quantitatively the ventilation of these zones., Comment: Ninth International IBPSA Conference, Montr\'eal : Canada (2005)

Published
2014

4. Multiple model approach and experimental validation of a residential air-to-air heat pump

Author

Garde, François, Boyer, Harry, Pignolet, Florence, Lucas, Franck, and Brau, Jean

Subjects
Computer Science - Computational Engineering, Finance, and Science
Abstract

The beginning of this work is the achievement of a design tool, which is a multiple model software called " CODYRUN ", suitable for professionnals and usable by researchers. The original aspect of this software is that the designer has at his disposal a wide panel of choices between different heat transfer models More precisely, it consists in a multizone software integrating both natural ventilation and moisture tranfers . This software is developed on PC micro computer and gets advantage of the Microsoft WINDOWS front-end. Most of time, HVAC systems and specially domestic air conditioners, are taken into account in a very simplified way, or in a elaborated one. On one side,they are just supposed to supply the demand of cooling loads with an ideal control loop (no delay between the sollicitations and the time response of the system), The available outputs are initially the hourly cooling and heating consumptions without integrating the real caracteristics of the HVAC system This paper is also following the same multiple model approach than for the building modelling by defining different modelling levels for the air conditionning systems, from a very simplified one to a detailled one. An experimental validation is achieved in order to compare the sensitivity of each defined model and to point out the interaction between the thermal behaviour of the envelop and the electrical system consumption. For validation purposes, we will describe the data acquisition system. and the used real size test cell located in the University of Reunion island, Indian Ocean.

Published
2012

5. A Picard Newton method to solve non linear airflow networks

Author

Boyer, Harry, Bastide, Alain, Lauret, Alfred Jean Philippe, and Lucas, Franck

Subjects
Computer Science - Computational Engineering, Finance, and Science
Abstract

In detailled buiding simulation models, airflow modelling and solving are still open and crucial problems, specially in the case of open buildings as encountered in tropical climates. As a consequence, wind speed conditioning indoor thermal comfort or energy needs in case of air conditionning are uneasy to predict. A first part of the problem is the lack of reliable and usable large opening elementary modelling and another one concerns the numerical solving of airflow network. This non linear pressure system is solved by numerous methods mainly based on Newton Raphson (NR) method. This paper is adressing this part of the difficulty, in our software CODYRUN. After model checks, we propose to use Picard method (known also as fixed point) to initialise zone pressures. A linear system (extracted from the non linear set of equations) is solved around 10 times at each time step and NR uses this result for initial values. Known to be uniformly but slowly convergent, this method appears to be really powerful for the building pressure system. The comparison of the methods in terms of number of iterations is illustrated using a real test case experiment., Comment: IASTED Modelling and Simulation Conference (MS0 2005), Orangestad : Aruba (2005)

Published
2012

6. A Comparison between CODYRUN and TRNSYS, simulation models for thermal buildings behaviour

Author

Lucas, Franck, Mara, Thierry Alex, Garde, François, and Boyer, Harry

Subjects
Computer Science - Computational Engineering, Finance, and Science
Abstract

Simulation codes of thermal behaviour could significantly improve housing construction design. Among the existing software, CODYRUN and TRNSYS are calculations codes of different conceptions. CODYRUN is exclusively dedicated to housing thermal behaviour, whereas TRNSYS is more generally used on any thermal system. The purpose of this article is to compare these two instruments in two different conditions . We will first modelize a mono-zone test cell, and analyse the results by means of signal treatment methods. Then, we will modelize a real case of multi-zone housing, representative of housing in wet tropical climates. We could so evaluate influences of meteorological and building description data on model errors.

Published
2012

11. Assessing solar resource and photovoltaic production in Tahiti from ground-based measurements

Author

Hopuare Marania, Lucas-Svay Lorène, Ortega Pascal, Lucas Franck, and Laurent Victoire

Subjects
Environmental sciences, GE1-350
Abstract

This study focuses on the solar resource available at Faaa, Tahiti (17.5°S, 149.5°W) thanks to 10 year-long solar irradiance time series. Faaa’s global horizontal irradiance ranges from 14 MJ.m-2.day-1 (June) to 21 MJ.m-2.day-1 (November) in agreement with the sun’s annual path, while clearness index ranges from 0.5 (January) to 0.67 (July), in agreement with the wet and dry seasons. The Global Solar Atlas satellite-derived dataset shows acceptable relative error when compared to Faaa in situ measurements. This product could then be used for other coastal areas of Tahiti. The annual energy output of a single PV module is 256.7 kWh, which corresponds to 7 % of the annual consumption of a typical household in Tahiti. The capacity factor reaches 22.5 %, which makes Faaa a good site for harnessing solar resource.

Published
2019
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15. Using CFD simulation to improve estimation of wind pressure coefficient for naturally-ventilated buildings in tropical climate

Author

Zubialde-Elzaurdia, Matthieu, Lucas, Franck, Bastide, Alain, Université de la Polynésie Française (UPF), Géopôle du Pacifique Sud (GePaSUD), Physique et Ingénierie Mathématique pour l'Énergie, l'environnemeNt et le bâtimenT (PIMENT), Université de La Réunion (UR), and Delcambre-Maillard, Elodie

Subjects
Natural ventilation, airflow network model, [INFO]Computer Science [cs], computational fluid dynamics, [INFO] Computer Science [cs], wind pressure coefficient
Abstract

International audience; Building energy simulation (BES) and Airflow network (AFN) programs generally incorporate wind pressure coefficients (Cp) estimated from secondary sources, namely data bases or analytical models. As these coefficients are influenced by a wide range of parameters, it is difficult to obtain reliable Cp data. This leads to uncertainties in BES-AFN models results, especially for naturally ventilated building studies, where air change rate which strongly depends on Cp, is a key value for thermal comfort and energy consumption results. This study focuses on naturally ventilated buildings in tropical climate and presents an alternative approach to estimate wind pressure coefficient. Computational fluid dynamics (CFD) simulations are performed to calculate wind-driven airflow rates at building opening level. Then wind pressure coefficient difference ΔCp is calculated from large opening equation to be used as input data in BES-AFN program. Numerical simulations are performed for various wind directions on a typical cross-ventilated isolated building and a more complex building with opposite large openings. CFD results of wind pressure coefficient difference and airflow rate are compared to those obtained from AFN model using two different Cp sources. The results show that the calculated values vary greatly depending on the method used and highlight that an accurate estimation of wind pressure coefficient is a key parameter for evaluating natural ventilation in buildings.

Published
2019

17. Etude expérimentale d'un prototype ETM à La Réunion

Author

Sinama, Frantz, Journoud, Audrey, Dijoux, Alexandre, Lucas, Franck, Clauzade, Bertrand, Castaing-Lasvignottes, Jean, Marc, Olivier, Physique et Ingénierie Mathématique pour l'Énergie, l'environnemeNt et le bâtimenT (PIMENT), Université de La Réunion (UR), DCNS Group [Nantes] (DCNS-Nantes), DCNS group, SINAMA, Frantz, and Dijoux, Alexandre

Subjects
[PHYS]Physics [physics], [PHYS.MECA.THER] Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract

International audience; L'île de La Réunion, située dans l'Océan Indien, est confrontée à un contexte énergétique complexe. L'utilisation de L'Energie Thermique des Mers (ETM) offre une alternative intéressante aux énergies renouvelables classiques. En effet, en utilisant la différence de température présente entre l'eau de surface (entre 23 et 28 °C selon la saison) et l'eau en profondeur (environ 5°C à 1000 m), il est possible de produire de l'électricité grâce à un cycle organique de Rankine (ORC). Cette technologie entre dans le plan d'autonomie électrique de la Région Réunion prévu pour 2030. Cet article présente l'installation expérimentale appelée PAT ETM (Prototype A Terre Energie Thermique des Mers). L'ammoniac est le fluide de travail utilisé et le niveau de puissance échangée dans le condenseur ou l'évaporateur est d'environ 500 kW pour une production d'électricité de l'ordre de 15 kW. La qualité des résultats et de l'analyse étant très dépendante des moyens de mesure, un effort particulier a été réalisé en la matière ainsi qu'au niveau du contrôle/commande sur ce prototype et fait l'objet d'une présentation détaillée. Un seul point expérimental est présenté et analysé en termes de température, de pression, de débit, de puissance et de bilan énergétique. Du fait d'un écart de température entre sources assez faible, le rendement thermique est lui aussi faible (2,5 %) mais néanmoins supérieur aux valeurs obtenues sur d'autres prototypes. Nomenclature P pression, Pa h enthalpie spécifique, J.kg-1 s entropie spécifique, J.kg-1 .K-1  W puissance mécanique, W  Q puissance échangée, W  m débit massique, kg.s-1 T température, K Indices et exposants R Réel V Virtuel pompe Pompe

Published
2016

19. Modeling of a thermal storage system incorporated into a solar cooling installation in an office building

Author

Marc, Olivier, Guillou, Paul, Sinama, Frantz, Lucas, Franck, Praene, Jean-Philippe, Castaing-Lasvignottes, Jean, Physique et Ingénierie Mathématique pour l'Énergie, l'environnemeNt et le bâtimenT (PIMENT), Université de La Réunion (UR), and Guillou, Paul

Subjects
[PHYS]Physics [physics], Solar cooling, thermal storage, modeling, phase change material, [PHYS] Physics [physics]
Abstract

International audience; During the last twenty years, the comfort and cooling requirements of office buildings and occupants have evolved significantly in Reunion Island, particularly during the summer period. This intensive use of air conditioning has resulted in a significant increase in electricity consumption such as traditional cooling technologies (mechanical vapor compression systems). In this context, solar cooling systems are one of the more interesting alternatives to conventional air conditioning systems. Thus in 2008, the PIMENT laboratory in Reunion Island proposed to set up an experimental platform called "RAFSOL", on the University Institute of Technology of Saint-Pierre, to study the absorption solar cooling technology for a University building. Experimental and numerical investigations of RAFSOL allowed to identify several research topics to improve global performances of the installation. One of them concerns the incorporation of a new thermal storage into the solar cooling system. Indeed, the addition of thermal storage (hot and/or cold) give the following advantages: (i) sufficient cooling power to cover the entire building’s needs, (ii) intelligent use the weekend energy potential, (iii) prevents overheating of the solar loop because of lower cooling needs. This thermal storage would also improve the system performance since it brings the temperatures of the hot and cold sources closer to their nominal values and thus optimizes the running time of the absorption chiller. In this work we decided to study only the incorporation of a hot thermal storage composed of a phase change material, and to investigate the influence of this storage on the solar cooling system performances. Three different phase change temperatures are investigated according to the state of art of this echnology: 79, 84 and 90°C. Simulation results are then analyzed and discussed to identify the optimal configuration of the thermal storage. In this first approach, the results show that the most interesting melting temperature, to improve most of performance indicators is 79°C.

Published
2015

20. Assistance technique pour l'optimisation des performances thermiques et énergétiques : le cas de la médiathèque du Tampon

Author

Garde, François, Lucas, Franck, Boyer, Harry, Adelard, Laetitia, Bastide, Alain, Boyer, Harry, Physique et Ingénierie Mathématique pour l'Énergie, l'environnemeNt et le bâtimenT (PIMENT), Université de La Réunion (UR), and Contrat SODEGIS

Subjects
[PHYS.MECA.THER] Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph], assistance maîtrise ouvrage, CODYRUN, Simulation, [SPI.MECA.THER] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph]
Abstract

L'objectif des simulations est d'apporter un appui technique à l'équipe de maîtrise d'œuvre du projet pour l'optimisation du confort hygro-thermique et des consommations énergétiques. Les simulations seront effectuées sur les zones de l'Administration et du bâtiment central avec le logiciel CODYRUN et pour deux périodes de l'année (été et hiver). Elle permettront d'optimiser, sur le plan de la conception et du dimensionnement, à la fois les composants d'enveloppe et les équipements énergétiques de ventilation de traitement d'air.

Published
2012

21. Simulation of a solar absorption system

Author

Praene, Jean-Philippe, Morau, Dominique, Lucas, Franck, Garde, François, Boyer, Harry, Physique et Ingénierie Mathématique pour l'Énergie, l'environnemeNt et le bâtimenT (PIMENT), Université de La Réunion (UR), and Boyer, Harry

Subjects
solar collectors, [PHYS.MECA.THER] Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], solar energy, [PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph], solar refrigerators, CODYRUN, [SPI.MECA.THER] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph]
Abstract

International audience; This paper describes the dynamic modeling of a solar absorption cooling plant that will be built for both research and demonstration purposes by the end of 2007. The synchronizing of cooling loads with solar radiation intensity is an important advantage when utilizing solar energy in air conditioning in buildings. The first part of this work deals with the dynamic modeling of an evacuated tube collector. A field of these collectors feed a single-effect absorption chiller of 35 kW nominal cooling capacity. The simulation model has been done in a modular way under TRNSYS16. In a second part, simulation and optimization of the system has been investigated in order to determine the effect of several parameters (collector area, tank volume...) on chiller performance.

Published
2008

22. Simulation And Optimization of a Solar Absorption Cooling System Using Evacuated Tube Collectors

Author

Praene, Jean-Philippe, Bastide, Alain, Lucas, Franck, Garde, François, Boyer, Harry, Physique et Ingénierie Mathématique pour l'Énergie, l'environnemeNt et le bâtimenT (PIMENT), Université de La Réunion (UR), and Boyer, Harry

Subjects
[PHYS.MECA.THER] Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph]
Abstract

International audience; SUMMARY Summer air conditioning represents a growing market in commercial and residential buildings. Solar energy is a very interesting energy source because of its advantages. Instead of a compressor system, which uses electricity, an absorption cooling system needs only heat produced by a solar collector plant. Furthermore, Reunion Island has a high solar energy potential. The yearly average solar-radiation and is 5.4 kWh/m²/day. This paper presents a solar-powered, single stage, absorption cooling system, using a water–lithium bromide solution. The first part of this work deals with the dynamic modeling of an evacuated tube collector used for the simulation of heat production. In a second part, simulation and optimization of the system has been investigated in order to determine the optimum of solar collector plant surface, storage tank volume and nominal capacity of the absorption chiller. A new building code was added under TRNSYS16, to have dynamic coupling between building loads and cooling production.

Published
2007

23. Utilisation d'outils de simulations dynamiques pour l'optimisation des performances d'un bâtiment en climat tropical

Author

Lucas, Franck, Adelard, Laetitia, Miranville, Frédéric, Garde, François, Boyer, Harry, Physique et Ingénierie Mathématique pour l'Énergie, l'environnemeNt et le bâtimenT (PIMENT), Université de La Réunion (UR), and Boyer, Harry

Subjects
conception thermique, [PHYS.MECA.THER] Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], confort, [PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph], CODYRUN, Simulation, [SPI.MECA.THER] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph]
Abstract

Actes disposibles, http://www.esim.ca/2006; International audience; Lors de la construction d'un nouveau bâtiment, en phase d'avant projet, une procédure d'optimisation permet d'obtenir des améliorations sensibles des performances énergétiques. Dans le cadre d'une mission d'assistance à maîtrise d'ouvrage, une étude complète sur une médiathèque située en climat tropical humide montre que le confort, la consommation énergétique et la salubrité du bâtiment peuvent être amélioré grâce à l'utilisation d'outils de simulations dynamiques. Ces outils, un code de simulation dynamique, un générateur de séquences climatiques spécifiques et un logiciel d'évaluation des indices de confort, permettent d'évaluer précisément l'impact des améliorations envisagées. L'étude, basée sur une méthode d'optimisation itérative, propose un ensemble cohérent de solutions passives améliorant la gestion des énergies mais aussi les conditions de confort. Cet article traite ainsi des caractéristiques de l'enveloppe, de l'influence du taux de ventilation, de la disposition de protections solaires et de l'utilisation de systèmes de conditionnement d'air suivant différents scenarii.

Published
2006

24. Simulations de dispositifs du type Mur Trombe avec CODYRUN

Author

Boyer, Harry, Lucas, Franck, Miranville, Frédéric, Bastide, Alain, Morau, Dominique, Physique et Ingénierie Mathématique pour l'Énergie, l'environnemeNt et le bâtimenT (PIMENT), Université de La Réunion (UR), and Boyer, Harry

Subjects
[PHYS.MECA.THER] Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], Mur Trombe, [PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph], CODYRUN, Simulation, [SPI.MECA.THER] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph]
Abstract

Actes disposibles, http://www.esim.ca/2006; International audience; Les dispositifs Mur Trombe ont fait l'objet de nombreuses études en climat tempéré et ont prouvé leur efficacité en tant que système de chauffage passif. Vis à vis du détail de la modélisation associée, un couplage fin (car faisant intervenir plusieurs modes de transfert) entre la pièce et le dispositif est nécessaire. Avec CODYRUN développé à l'Université de La Réunion, des résultats de simulation sont présentés au départ d'un fichier météorologique et d'un habitat type de Madagascar. Ces murs capteurs stockeurs s'avèrent pouvoir améliorer notablement les conditions de confort En utilisant des sorties spécifiques (débits enthalpiques, apports par conduction, indices de confort, ... ), une analyse de l'efficacité du dispositif est menée et démontre les avantages de ce mode de chauffage passif et peu onéreux.

Published
2006

25. Intégration à TRNSYS du noyau de CODYRUN, code de simulation thermo-aéraulique de bâtiments : le Type 59

Author

Bastide, Alain, Boyer, Harry, Lauret, Philippe, Lucas, Franck, Garde, François, Physique et Ingénierie Mathématique pour l'Énergie, l'environnemeNt et le bâtimenT (PIMENT), Université de La Réunion (UR), and Boyer, Harry

Subjects
TRNSYS, [PHYS.MECA.THER] Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph], Physique du bâtiment, CODYRUN, simulation, [SPI.MECA.THER] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph]
Abstract

National audience; Ce papier traite de l'intégration à l'environnement TRNSYS du noyau de calcul d'un modèle développé depuis une dizaine d'années à l'Université de la Réunion, développement entrepris initialement en partenariat avec le CETHIL de l'INSA de Lyon. Il part du constat d'une segmentation des utilisateurs-développeurs en thermique des bâtiments, partagés entre un groupe sous environnement TRNSYS (type19 et 56 principalement) et l'autre mettant en œuvre des codes spécifiques (ESP, APACHE, BUS, CODYRUN, ...). Chacun de ces choix possède des avantages et/ou inconvénients, le bénéfice de l'environnement TRNSYS étant principalement celui de la ré-utilisabilité des modules construits par la communauté.

Published
2001

26. Use of a new trnsys type using neural network for non linear models creation

Author

Adelard, Laetitia, Lucas, Franck, Lauret, Philippe, Fock, Eric, Boyer, Harry, Physique et Ingénierie Mathématique pour l'Énergie, l'environnemeNt et le bâtimenT (PIMENT), and Université de La Réunion (UR)

Subjects
HVAC simulations, Non linear stochastic models, Trnsys platform, neural network, [PHYS.MECA.THER] Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph], [SPI.MECA.THER] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph]
Abstract

International audience; Model determination must sometimes be rapidly made because of missing data in a building simulation. This paper will deal about the creation of a new trnsys type using neural network method to create new non linear models. The new type 111 integrates both the models creation process, and the use of this model immediately in simulations. This new type will be used in Hvac building simulation in trnsys environment but it can also be used in a new weather data generator. Illustration of such a type is made in HVAC simulation, for the determination of the cooling power, or for missing data in meteorological data files like long wave radiation estimation.

Published
2001

27. Nécessité de l'approche multimodèle dans la modélisation des systèmes de traitement d'air

Author

Garde, François, Lucas, Franck, Boyer, Harry, Brau, Jean, Physique et Ingénierie Mathématique pour l'Énergie, l'environnemeNt et le bâtimenT (PIMENT), Université de La Réunion (UR), Centre de Thermique de Lyon (CETHIL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA), and Boyer, Harry

Subjects
STA, [PHYS.MECA.THER] Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph], Système de traitemet d'air, CODYRUN, [SPI.MECA.THER] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph]
Abstract

International audience; La modélisation des systèmes et le couplage bâtiment/systèmes permet de prédire la consommation et le dimensionnement de l'installation de climatisation. Malheureusement, les sytèmes sont souvent dimensionnés pour des conditions extrèmes et leur fonctionnement réel atteint rarement 60% de la puissance pour laquelle ils ont été dimensionnés. Dans ce cas, les modèles horaires utilisés en thermique du bâtiment se révèlent peu précis car ils ne tiennent pas compte de la régulation et du temps de fonctionnement du système. Nous nous proposons de présenter dans ce papier une approche multimodèle dans la modélisation des systèmes de traitement d'air. Trois modèles de systèmes ont été développés à différents niveaux de finesses et ont été intégrés dans un code de calcul thermo-aéraulique développé à l'Université de la Réunion. Le modèle le plus simple est un modèle horaire, le plus détaillé est un modèle à pas de temps réduit tenant compte à la fois de la régulation du système et de l'évolution en régime dynamique. Une comparaison inter-modèle réalisée à différents taux de charge de climatiseur a permis de mettre en évidence la précision de chaque modèle

Published
1999

28. A Comparison between CODYRUN and TRNSYS, simulation models for thermal buildings behaviour

Author

Lucas, Franck, Mara, Thierry Alex, Garde, François, Boyer, Harry, Physique et Ingénierie Mathématique pour l'Énergie, l'environnemeNt et le bâtimenT (PIMENT), and Université de La Réunion (UR)

Subjects
Computational Engineering, Finance, and Science (cs.CE), FOS: Computer and information sciences, TRNSYS, validation, [PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph], CODYRUN, Computer Science - Computational Engineering, Finance, and Science
Abstract

International audience; Simulation codes of thermal behaviour could significantly improve housing construction design. Among the existing software, CODYRUN and TRNSYS are calculations codes of different conceptions. CODYRUN is exclusively dedicated to housing thermal behaviour, whereas TRNSYS is more generally used on any thermal system. The purpose of this article is to compare these two instruments in two different conditions . We will first modelize a mono-zone test cell, and analyse the results by means of signal treatment methods. Then, we will modelize a real case of multi-zone housing, representative of housing in wet tropical climates. We could so evaluate influences of meteorological and building description data on model errors.

Published
1998

30. Les recepteurs aux enterotoxines bacteriennes

Author

Lucas, Franck, Corthier, G, Unité de recherche d'Écologie et Physiologie du Système Digestif (UEPSD), Institut National de la Recherche Agronomique (INRA), Revues Inra, Import, and ProdInra, Migration

Subjects
[SDV] Life Sciences [q-bio], [SDV.IMM] Life Sciences [q-bio]/Immunology, [SDV.BA] Life Sciences [q-bio]/Animal biology, [SDV.SPEE] Life Sciences [q-bio]/Santé publique et épidémiologie, [SDV]Life Sciences [q-bio], [SDV.GEN.GA] Life Sciences [q-bio]/Genetics/Animal genetics, [SDV.NEU] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC], [SDV.BC.IC] Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB], [SDV.BBM.BM] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology, [SDV.BC] Life Sciences [q-bio]/Cellular Biology, [SDV.MP] Life Sciences [q-bio]/Microbiology and Parasitology, ComputingMilieux_MISCELLANEOUS
Abstract

50 ref.

Published
1991

31. Les enterotoxines bacteriennes : structure, mode d'action

Author

Lucas, Franck, Popoff, M, Corthier, G, Unité de recherche d'Écologie et Physiologie du Système Digestif (UEPSD), Institut National de la Recherche Agronomique (INRA), Revues Inra, Import, and ProdInra, Migration

Subjects
[SDV] Life Sciences [q-bio], CYTOTONICITE, [SDV.IMM] Life Sciences [q-bio]/Immunology, [SDV.BA] Life Sciences [q-bio]/Animal biology, [SDV.SPEE] Life Sciences [q-bio]/Santé publique et épidémiologie, [SDV]Life Sciences [q-bio], [SDV.GEN.GA] Life Sciences [q-bio]/Genetics/Animal genetics, [SDV.NEU] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC], [SDV.BC.IC] Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB], [SDV.BBM.BM] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology, [SDV.BC] Life Sciences [q-bio]/Cellular Biology, [SDV.MP] Life Sciences [q-bio]/Microbiology and Parasitology, ComputingMilieux_MISCELLANEOUS
Abstract

64 ref.

Published
1991

32. Indoor Humidity Modeling and Evaluation of Condensation on Interior Surfaces.

Author

Lucas, Franck and Miranville, Frederick

Subjects
*MOISTURE, *CONDENSATION, *PHASE transitions, *THERMAL analysis, *SIMULATION methods & models, *BUILDINGS
Abstract

In tropical humid climates, moisture and condensation on walls lead to significant damage of buildings. The purpose of this article is to present a numerical model to improve the prediction of internal humidity in buildings. Thermal simulation codes usually evaluate moisture due only to airflow transfers. The model presented takes into account the moisture transfers between walls and air inside a zone. It allows a forecast of the quantities of liquid condensed on a surface. An experimental comparison is presented to appreciate the improvement of the model. [ABSTRACT FROM AUTHOR]

Published
2004

33. Energy performance assessment of Sea Water Air Conditioning (SWAC) as a solution toward net zero carbon emissions: A case study in French Polynesia

Author

Sanjivy, Kanhan, Marc, Olivier, Davies, Neil, and Lucas, Franck

Abstract

Sea Water Air Conditioning (SWAC) technology uses deep ocean water to cool buildings. It is a non-intermittent renewable thermal energy used directly without any transformation. It may replace other air-conditioning systems powered by electrical energy (mechanical vapor compression thermodynamic cycle) or powered by other renewable energies (solar heating and cooling systems). Despite its theoretical appeal as a solution to help achieve net-zero carbon emissions, and the existence of successful deployments, SWAC technology remains scarce worldwide mainly due to its investment cost (CAPEX). One reason for this failure to scale might be the absence of experimental data detailing energy performance of SWAC systems in real-world, commercial settings. Here is presented the performance of an existing 2.4 MW SWAC system, operated by The Brando resort on the atoll of Tetiaroa in French Polynesia. Under a tropical climate, experimental results show that the Coefficient of Performance (COP) of the SWAC system can reach 20 to 150 depending on the secondary loop length, compared with conventional vapor compression systems that peak at around 5 for the most efficient. To put this in terms of carbon emissions avoided, conventional unitary split systems running in similar hotels on neighboring islands in French Polynesia (COP around 3.5) emit some 860 Tons/year compared to the estimated 225 Tons/year emitted (approximated with the emissions factor of French Polynesia in 2019) operating the Tetiaroa SWAC.

Published
2022
Full Text
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34. Characteristics, management, and prognosis of elderly patients with COVID-19 admitted in the ICU during the first wave: insights from the COVID-ICU study

Author

Dres, Martin, Hajage, David, Lebbah, Said, Kimmoun, Antoine, Pham, Tai, Béduneau, Gaëtan, Combes, Alain, Mercat, Alain, Guidet, Bertrand, Demoule, Alexandre, Schmidt, Matthieu, Neurophysiologie Respiratoire Expérimentale et Clinique (UMRS 1158), Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU), CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU), Institut Pierre Louis d'Epidémiologie et de Santé Publique (iPLESP), Centre Hospitalier Régional Universitaire de Nancy (CHRU Nancy), Défaillance Cardiovasculaire Aiguë et Chronique (DCAC), Centre Hospitalier Régional Universitaire de Nancy (CHRU Nancy)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Lorraine (UL), Hôpital Bicêtre, Centre de recherche en épidémiologie et santé des populations (CESP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Paul Brousse-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Paris-Saclay, Groupe de Recherche sur le Handicap Ventilatoire et Neurologique (GRHVN), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institute for Research and Innovation in Biomedicine (IRIB), Normandie Université (NU)-Normandie Université (NU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), CHU Rouen, Normandie Université (NU), Unité de Recherche sur les Maladies Cardiovasculaires, du Métabolisme et de la Nutrition = Research Unit on Cardiovascular and Metabolic Diseases (ICAN), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Institut de Cardiométabolisme et Nutrition = Institute of Cardiometabolism and Nutrition [CHU Pitié Salpêtrière] (IHU ICAN), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-CHU Pitié-Salpêtrière [AP-HP], Centre Hospitalier Universitaire d'Angers (CHU Angers), PRES Université Nantes Angers Le Mans (UNAM), Université d'Angers (UA), CHU Saint-Antoine [AP-HP], COVID-ICU investigators: Alain Mercat, Pierre Asfar, François Beloncle, Julien Demiselle, Tài Pham, Arthur Pavot, Xavier Monnet, Christian Richard, Alexandre Demoule, Martin Dres, Julien Mayaux, Alexandra Beurton, Cédric Daubin, Richard Descamps, Aurélie Joret, Damien Du Cheyron, Frédéric Pene, Jean-Daniel Chiche, Mathieu Jozwiak, Paul Jaubert, Guillaume Voiriot, Muriel Fartoukh, Marion Teulier, Clarisse Blayau, Erwen L'Her, Cécile Aubron, Laetitia Bodenes, Nicolas Ferriere, Johann Auchabie, Anthony Le Meur, Sylvain Pignal, Thierry Mazzoni, Jean-Pierre Quenot, Pascal Andreu, Jean-Baptiste Roudau, Marie Labruyère, Saad Nseir, Sébastien Preau, Julien Poissy, Daniel Mathieu, Sarah Benhamida, Rémi Paulet, Nicolas Roucaud, Martial Thyrault, Florence Daviet, Sami Hraiech, Gabriel Parzy, Aude Sylvestre, Sébastien Jochmans, Anne-Laure Bouilland, Mehran Monchi, Marc Danguy des Déserts, Quentin Mathais, Gwendoline Rager, Pierre Pasquier, Reignier Jean, Seguin Amélie, Garret Charlotte, Canet Emmanuel, Jean Dellamonica, Clément Saccheri, Romain Lombardi, Yanis Kouchit, Sophie Jacquier, Armelle Mathonnet, Mai-AhnNay, Isabelle Runge, Frédéric Martino, Laure Flurin, Amélie Rolle, Michel Carles, Rémi Coudroy, Arnaud W Thille, Jean-Pierre Frat, Maeva Rodriguez, Pascal Beuret, Audrey Tientcheu, Arthur Vincent, Florian Michelin, Marie Anne Melone, Maxime Gauzi, Arnaud Guilbert, Geoffrey Kouadri, Valérie Gissot, Stéphan Ehrmann, Charlotte Salmon Gandonniere, Djlali Elaroussi, Agathe Delbove, Yannick Fedun, Julien Huntzinger, Eddy Lebas, Grâce Kisoka, Céline Grégoire, Stella Marchetta, Bernard Lambermont, Laurent Argaud, Thomas Baudry, Pierre-Jean Bertrand, Auguste Dargent, Christophe Guitton, Nicolas Chudeau, Mickaël Landais, Cédric Darreau, Alexis Ferre, Antoine Gros, Guillaume Lacave, Fabrice Bruneel, Mathilde Neuville, Jérôme Devaquet, Guillaume Tachon, Richard Gallot, Riad Chelha, Arnaud Galbois, Anne Jallot, Ludivine Chalumeau Lemoine, Khaldoun Kuteifan, Valentin Pointurier, Louise-Marie Jandeaux, Joy Mootien, Charles Damoisel, Benjamin Sztrymf, Matthieu Schmidt, Alain Combes, Juliette Chommeloux, Charles Edouard Luyt, Frédérique Schortgen, Leon Rusel, Camille Jung, Florent Gobert, Damien Vimpere, Lionel Lamhaut, Bertrand Sauneuf, Liliane Charrrier, Julien Calus, Isabelle Desmeules, Benoît Painvin, Jean-Marc Tadie, Vincent Castelain, Baptiste Michard, Jean-Etienne Herbrecht, Mathieu Baldacini, Nicolas Weiss, Sophie Demeret, Clémence Marois, Benjamin Rohaut, Pierre-Henri Moury, Anne-Charlotte Savida, Emmanuel Couadau, Mathieu Série, Nica Alexandru, Cédric Bruel, Candice Fontaine, Sonia Garrigou, Juliette Courtiade Mahler, Maxime Leclerc, Michel Ramakers, Pierre Garçon, Nicole Massou, Ly Van Vong, Juliane Sen, Nolwenn Lucas, Franck Chemouni, Annabelle Stoclin, Alexandre Avenel, Henri Faure, Angélie Gentilhomme, Sylvie Ricome, Paul Abraham, Céline Monard, Julien Textoris, Thomas Rimmele, Florent Montini, Gabriel Lejour, Thierry Lazard, Isabelle Etienney, Younes Kerroumi, Claire Dupuis, Marine Bereiziat, Elisabeth Coupez, François Thouy, Clémet Hoffmann, Nicolas Donat, Violaine Muller, Thibault Martinez, Antoine Kimmoun, Audrey Jacquot, Matthieu Mattei, Bruno Levy, Ramin Ravan, Loïc Dopeux, Jean-Mathias Liteaudon, Delphine Roux, Brice Rey, Radu Anghel, Deborah Schenesse, Vincent Gevrey, Jermy Castanera, Philippe Petua, Benjamin Madeux, Otto Hartman, Michael Piagnerelli, Anne Joosten, Cinderella Noel, Patrick Biston, Thibaut Noel, Gurvan L E Bouar, Messabi Boukhanza, Elsa Demarest, Marie-France Bajolet, Nathanaël Charrier, Audrey Quenet, Cécile Zylberfajn, Nicolas Dufour, Buno Mégarbane, SqébastianVoicu, Nicolas Deye, Isabelle Malissin, François Legay, Matthieu Debarre, Nicolas Barbarot, Pierre Fillatre, Bertrand Delord, Thomas Laterrade, Tahar Saghi, Wilfried Pujol, Pierre Julien Cungi, Pierre Esnault, Mickael Cardinale, Vivien Hong Tuan Ha, Grégory Fleury, Marie-Ange Brou, Daniel Zafimahazo, David Tran-Van, Patrick Avargues, Lisa Carenco, Nicolas Robin, Alexandre Ouali, Lucie Houdou, Christophe Le Terrier, Noémie Suh, Steve Primmaz, Jérome Pugin, Emmanuel Weiss, Tobias Gauss, Jean-Denis Moyer, Catherine Paugam Burtz, Béatrice La Combe, Rolland Smonig, Jade Violleau, Pauline Cailliez, Jonathan Chelly, Antoine Marchalot, Cécile Saladin, Christelle Bigot, Pierre-Marie Fayolle, Jules Fatséas, Amr Ibrahim, Dabor Resiere, Rabih Hage, Clémentine Cholet, Marie Cantier, Pierre Trouiler, Philippe Montravers, Brice Lortat-Jacob, Sebastien Tanaka, Alexy Tran Dinh, Jacques Duranteau, Anatole Harrois, Guillaume Dubreuil, Marie Werner, Anne Godier, Sophie Hamada, Diane Zlotnik, Hélène Nougue, Armand Mekontso-Dessap, Guillaume Carteaux, Keyvan Razazi, Nicolas De Prost, Nicolas Mongardon, Olivier Langeron, Eric Levesque, Arié Attias, Charles de Roquetaillade, Benjamin G Chousterman, Alexandre Mebazaa, Etienne Gayat, Marc Garnier, Emmanuel Pardo, Lea Satre-Buisson, Christophe Gutton, Elise Yvin, Clémence Marcault, Elie Azoulay, Michael Darmon, Hafid Ait Oufella, Geoffroy Hariri, Tomas Urbina, Sandie Mazerand, Nicholas Heming, Francesca Santi, Pierre Moine, Djillali Annane, Adrien Bouglé, Edris Omar, Aymeric Lancelot, Emmanuelle Begot, Gaétan Plantefeve, Damien Contou, Hervé Mentec, Olivier Pajot, Stanislas Faguer, Olivier Cointault, Laurence Lavayssiere, Marie-Béatrice Nogier, Matthieu Jamme, Claire Pichereau, Jan Hayon, Hervé Outin, François Dépret, Maxime Coutrot, Maité Chaussard, Lucie Guillemet, Pierre Goffin, Romain Thouny, Julien Guntz, Laurent Jadot, Romain Persichini, Vanessa Jean-Michel, Hugues Georges, Thomas Caulier, Gaël Pradel, Marie-Hélène Hausermann, ThiMy Hue Nguyen-Valat, Michel Boudinaud, Emmanuel Vivier, Sylvène Rosseli, Gaël Bourdin, Christian Pommier, Marc Vinclair, Simon Poignant, Sandrine Mons, Wulfran Bougouin, Franklin Bruna, Quentin Maestraggi, Christian Roth, Laurent Bitker, François Dhelft, Justine Bonnet-Chateau, Mathilde Filippelli, Tristan Morichau-Beauchant, Stéphane Thierry, Charlotte Le Roy, Mélanie Saint Jouan, Bruno Goncalves, Aurélien Mazeraud, Matthieu Daniel, Tarek Sharshar, Cyril Cadoz, RostaneGaci, Sébastien Gette, Guillaune Louis, Sophe-Caroline Sacleux, Marie-Amélie Ordan, Aurélie Cravoisy, Marie Conrad, Guilhem Courte, Sébastien Gibot, Younès Benzidi, Claudia Casella, Laurent Serpin, Jean-Lou Setti, Marie-Catherine Besse, Anna Bourreau, Jérôme Pillot, Caroline Rivera, Camille Vinclair, Marie-Aline Robaux, Chloé Achino, Marie-Charlotte Delignette, Tessa Mazard, Frédéric Aubrun, Bruno Bouchet, Aurélien Frérou, Laura Muller, Charlotte Quentin, Samuel Degoul, Xavier Stihle, Claude Sumian, Nicoletta Bergero, Bernard Lanaspre, Hervé Quintard, Eve Marie Maiziere, Pierre-Yves Egreteau, Guillaume Leloup, Florin Berteau, Marjolaine Cottrel, Marie Bouteloup, Matthieu Jeannot, Quentin Blanc, Julien Saison, Isabelle Geneau, Romaric Grenot, Abdel Ouchike, Pascal Hazera, Anne-Lyse Masse, Suela Demiri, Corinne Vezinet, Elodie Baron, Deborah Benchetrit, Antoine Monsel, Grégoire Trebbia, Emmanuelle Schaack, Raphaël Lepecq, Mathieu Bobet, Christophe Vinsonneau, Thibault Dekeyser, Quentin Delforge, Imen Rahmani, Bérengère Vivet, Jonathan Paillot, Lucie Hierle, Claire Chaignat, Sarah Valette, Benoït Her, Jennifier Brunet, Mathieu Page, Fabienne Boiste, Anthony Collin, Florent Bavozet, Aude Garin, Mohamed Dlala, Kais Mhamdi, Bassem Beilouny, Alexandra Lavalard, Severine Perez, Benoit Veber, Pierre-Gildas Guitard, Philippe Gouin, Anna Lamacz, Fabienne Plouvier, Bertrand P Delaborde, Aïssa Kherchache, Amina Chaalal, Jean-Damien Ricard, Marc Amouretti, Santiago Freita-Ramos, Damien Roux, Jean-Michel Constantin, Mona Assefi, Marine Lecore, Agathe Selves, Florian Prevost, Christian Lamer, Ruiying Shi, Lyes Knani, Sébastien PiliFloury, Lucie Vettoretti, Michael Levy, Lucile Marsac, Stéphane Dauger, Sophie Guilmin-Crépon, Hadrien Winiszewski, Gael Piton, Thibaud Soumagne, Gilles Capellier, Jean-Baptiste Putegnat, Frédérique Bayle, Maya Perrou, Ghyslaine Thao, Guillaume Géri, Cyril Charron, Xavier Repessé, Antoine Vieillard-Baron, Mathieu Guilbart, Pierre-Alexandre Roger, Sébastien Hinard, Pierre-Yves Macq, Kevin Chaulier, Sylvie Goutte, Patrick Chillet, Anaïs Pitta, Barbara Darjent, Amandine Bruneau, Sigismond Lasocki, Maxime Leger, Soizic Gergaud, Pierre Lemarie, Nicolas Terzi, Carole Schwebel, Anaïs Dartevel, Louis-Marie Galerneau, Jean-Luc Diehl, Caroline Hauw-Berlemont, Nicolas Péron, Emmanuel Guérot, Abolfazl Mohebbi Amoli, Michel Benhamou, Jean-Pierre Deyme, Olivier Andremont, Diane Lena, Julien Cady, Arnaud Causeret, Arnaud De La Chapelle, Christophe Cracco, Stéphane Rouleau, David Schnell, Camille Foucault, Cécile Lory, Thibault Chapelle, Vincent Bruckert, Julie Garcia, Abdlazize Sahraoui, Nathalie Abbosh, Caroline Bornstain, Pierre Pernet, Florent Poirson, Ahmed Pasem, Philippe Karoubi, Virginie Poupinel, Caroline Gauthier, François Bouniol, Philippe Feuchere, Florent Bavozet, Anne Heron, Serge Carreira, Malo Emery, Anne Sophie Le Floch, Luana Giovannangeli, Nicolas Herzog, Christophe Giacardi, Thibaut Baudic, Chloé Thill, Said Lebbah, Jessica Palmyre, Florence Tubach, David Hajage, Nicolas Bonnet, Nathan Ebstein, Stéphane Gaudry, Yves Cohen, Julie Noublanche, Olivier Lesieur, Arnaud Sément, Isabel Roca-Cerezo, Michel Pascal, Nesrine Sma, Gwenhaël Colin, Jean-Claude Lacherade, Gauthier Bionz, Natacha Maquigneau, Pierre Bouzat, Michel Durand, Marie-Christine Hérault, Jean-Francois Payen, and dres, martin

Subjects
[SDV] Life Sciences [q-bio], Acute respiratory distress syndrome, Frailty, [SDV]Life Sciences [q-bio], Old patients, COVID-19, Intensive care unit, Mortality, Intubation
Abstract

International audience; Abstract Background The COVID-19 pandemic is a heavy burden in terms of health care resources. Future decision-making policies require consistent data on the management and prognosis of the older patients (> 70 years old) with COVID-19 admitted in the intensive care unit (ICU). Methods Characteristics, management, and prognosis of critically ill old patients (> 70 years) were extracted from the international prospective COVID-ICU database. A propensity score weighted-comparison evaluated the impact of intubation upon admission on Day-90 mortality. Results The analysis included 1199 (28% of the COVID-ICU cohort) patients (median [interquartile] age 74 [72–78] years). Fifty-three percent, 31%, and 16% were 70–74, 75–79, and over 80 years old, respectively. The most frequent comorbidities were chronic hypertension (62%), diabetes (30%), and chronic respiratory disease (25%). Median Clinical Frailty Scale was 3 (2–3). Upon admission, the PaO 2 /FiO 2 ratio was 154 (105–222). 740 (62%) patients were intubated on Day-1 and eventually 938 (78%) during their ICU stay. Overall Day-90 mortality was 46% and reached 67% among the 193 patients over 80 years old. Mortality was higher in older patients, diabetics, and those with a lower PaO 2 /FiO 2 ratio upon admission, cardiovascular dysfunction, and a shorter time between first symptoms and ICU admission. In propensity analysis, early intubation at ICU admission was associated with a significantly higher Day-90 mortality (42% vs 28%; hazard ratio 1.68; 95% CI 1.24–2.27; p

Published
2021

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