Comparison of the thermal performance between conventional and cob building

The appliance of sustainable development approach in building has urged construction industry to adopt proper measurements to protect environment and reduce residential building energy consumption and CO2 emissions. Thus, an increasing interest in alternative building materials has developed including the use of bio-based materials such as cob which is studied in this paper. In the previous work, many experimental and numerical studies have been carried out to characterize thermal behaviour of earth buildings, reduce its thermal conductivity and water content. In this paper, an experimental study is carried out to determine the thermal properties and energy performance of cob building. Cob samples within different soil and fiber contents are studied using an experimental set up instrumented with flux meters and micro-thermocouples in order to evaluate the local heat flux and thermal conductivity during stationary regime. The results are analysed and compared to deduce the performant mixes in terms of thermal behaviour while respecting the French thermal regulation. A static thermal simulation based on RT 2012 calculation method (the official French calculation method for the energy performance of new residential and commercial buildings according to France thermal regulation) is used to compare energy performance between conventional and cob building using the French climate data base

Realization and thermal characterization of thin-film optothermal microsensor

The aim of this investigation is to study thin-film thermoelectric linear arrays for high spatial temperature measurements and to analyze power laser energy profile. The sensitive area consists of a planar of 16 individual thin-film Au-Pd thermocouple junctions with 8 μm × 8 μm of surface area. This sensor allows 16 temperature measurements per 288 μm. It is processed by means of standard integrated circuit techniques. Thermal simulation of heat conduction in gold and palladium layers has been carried out. The sensor thermoelectric response has been characterized in transient regime and steady state. The time constant of thermocouple response is of the order of 140 μs. A linear relationship between the thermoelectric voltage and the incident power laser has been put in evidence. Using the linear array, a Gaussian profile of the incident laser beam is obtained

Unsteady steam condensation flow patterns inside a miniature tube

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Modeling and control of the offshore wind energy system based on 5MW DFIG connected to grid

International audienceThis paper presents the control strategies of an offshore wind energy system based on 5MW Doubly Fed Induction Generator (DFIG). The DFIG seems to be interesting for such high power wind generator systems. The proposed control strategies include the Maximum Power Tracking (MPPT) for the DFIG speed control, the active/reactive power control, and the DC-bus voltage control method. To show the performances of the control strategies, some simulation results are presented and analyzed using Matlab/Simulink software

Experimental Study of Unsteady Local Heat Transfer for Impinging Miniature Jet

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Experimental study of void fraction profils in pool boiling on a vertical surface

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Adaptive Fuzzy Logic Control for a Class of Unknown Nonlinear Dynamic Systems with Guaranteed Stability

In this paper, a stability analysis is suggested for adaptive fuzzy logic systems (FLSs) without the requirement of states measurement or estimation. Fuzzy logic is viewed as a powerful tool in providing accurate approximation of systems with uncertainties. The proposed methodology exploits the power of adaptive control theory to find a Lyapunov-based adaptation law for FLSs. As such, both stability and tracking problems are addressed for a class of nonlinear dynamic systems. The proposed method yields reduced complexity with respect to many adaptive FLSs available in the literature. In addition, the use of an observer to estimate immeasurable states is not required as in other methods. First, a stability analysis is presented for adaptive control. Then, results are extended to adaptive FLSs with unknown dynamics. A numeric illustrative example highlights the implementation details and the performance of the suggested scheme

Experimental and numerical investigations of local condensation heat transfer in a single square microchannel under variable heat flux

International audienceThis paper presents an experimental investigation on the local and average condensation heat transfer in a single noncircular microchannel. Furthermore, it develops one dimensional model for annular condensation flow in a microchannel under variable heat flux condition. The condensate film thickness is calculated for each location in a microchannel including the effects of capillary number, Boiling number, contact angle, heat flux, vapor pressure, and hydraulic diameter. A comparative study shows that the present model well predicts the experimental data concerning local condensation heat transfer coefficient. The mean deviation between the local predictions of the theoretical model with the measurements for local heat transfer coefficient is 20%. It is found that the correlation of Quan et al. (2008) [19] gives the good predictions of the measurements with maximum deviation of 13% at high Reynolds number

Réalisation d'un simulateur de gestion d'énergie électrique embarquée

L'objectif de l'article est la présentation d'un simulateur pour la gestion de l'énergie électrique embarquée à bord d'un véhicule. Ce simulateur se présente sous la forme d'une maquette pédagogique réalisée par des étudiants dans le cadre des projets du Master PROTEE (production et traitement de l'énergie électrique) de l'université de franche-comté. Il intègre des éléments issus de technologies récentes telles que l'alternodémareur qui équipe la Citroën C3, des supercondensateurs, un convertisseur d'énergie statique réversible (onduleur/redresseur), un volant d'inertie ainsi qu'une batterie classique. Ces divers éléments sont interconnectés entre eux de façon électrique ou mécanique. Le bon fonctionnement de l'ensemble a nécessité la réalisation de plusieurs cartes électroniques autour des microcontrôleurs PIC permettant l'exploitation dans un cadre pédagogique de la maquette. En effet, ces différentes cartes électroniques permettent de traiter les informations issues des différents capteurs, le contrôle du convertisseur statique, l'interface de dialogue avec l'utilisateur et un système informatique telle que dSPACE. Ces derniers sont introduits afin d'assurer, d'une part la supervision, la surveillance et la sûreté de fonctionnement de l'ensemble, et d'autre part, la mise en oeuvre de différentes stratégies de gestion de l'énergie. L'évaluation des différents rendements et puissances mécaniques et électriques mises en jeu est possible aussi bien en ligne qu'en différé puisque le système assure le stockage des différentes mesures. Ce projet est pluridisciplinaire et permet aux étudiants de faire le lien entre les différents modules enseignés en Master PROTEE

Numerical Modeling of Annular Film Condensation Inside a Miniature Tube

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