@article {1876, title = { Advanced materials for energy harvesting, storage, sensing and environmental engineering }, journal = { EUROPEAN PHYSICAL JOURNAL-APPLIED PHYSICS }, volume = {88}, year = {2020}, author = {M. EL-JOUAD and R. BENNACER and M. EL-GANAOUI and J.M. NUNZI} } @article {1883, title = { Some flow patterns within ventilation strategy coupled to energy efficiency }, journal = { EUROPEAN PHYSICAL JOURNAL-APPLIED PHYSICS }, volume = {88}, year = {2020}, abstract = {

Energy and buildings are increasingly becoming subjects for investigations, especially for the indoor air quality domain coupled to energy demand. The physics of fluids flowing inside enclosures bring basic models to understand and build better schemes. This paper is devoted to studying ventilation strategies in regards to Indoor Air Quality (IAQ) and energy efficiency in floor refreshing houses. A room model is considered in a simplified level, as a cavity heated on the external sidewall and cooled on the bottom ground surface. The external air injector is at variable positions and interacting with the needed cooling power; the air quality (mixing ability) and thermal comfort are also studied. The cooling efficiency inside the considered volume and the average air temperature are analyzed for a given temperature difference characterizing the natural convection level (Rayleigh number, Ra = 10(6)) and a horizontal ventilation (moderate Reynolds number Re = 10(2)). An obtained complex flow structure indicates that the natural convection and the forced flow (ventilation) act directly on the resulting patterns, mixing ability, heat exchange which in a straight line affect the thermal comfort and in fine the energy cost (cooling requirement).

}, author = {S. MORSLI and R. BENNACER and M. EL-GANAOUI and H. RAMENAH and A. CARMASOL} } @article {1832, title = { Integration of the PCM with intra-ventilation for improved thermal and inertial characteristics of the building envelope }, journal = { EUROPEAN PHYSICAL JOURNAL-APPLIED PHYSICS }, volume = {84}, year = {2019}, abstract = {

Several solutions based on phase change materials (PCM) are used for the thermal regulation of buildings. In this study, a combination of the inertial effect of PCM and intra-ventilation regulation is proposed. The purpose is to increase the thermal inertia of the building envelope leading to a fast passive and active cooling of the indoor environment. The principle of the solution is the use of a polymer-stabilized paraffin in external walls integrating ventilation pipes. For that, an experimental study of a hollow concrete block with PCM and ventilation tubes is conducted to test its thermal response. Gathered to this part, a 3D numerical model is developed under COMSOL Multiphysics (R). The obtained simulation results are in good agreement with the experimental data. A parametric study is then performed including its actual characteristics against several conditions; it is revealed that the use of PCM gathered to the ventilation tubes enhances the thermal phase shift. It is stated that the forced ventilation through the tubes makes it possible to manage the energy and contribute to the renewal of the air.

}, url = {https://hal.archives-ouvertes.fr/hal-02076663}, author = {A. LAAOUATNI and M. MARTAJI and R. BENNACER and M. EL-OMARI and L. BIN and M. EL-GANAOUI and A. Merabtine} } @article {1834, title = { Morphological Approach for Nonlinear Flow and Heat Transfer in Complex Bio-Composite Material }, journal = { HEAT TRANSFER ENGINEERING }, volume = {40}, year = {2019}, pages = {1486-1497}, abstract = {

The bio-based materials have experienced in recent years a relevant evolution in construction and for many building applications. Despite the efforts to develop new solutions to achieve the objectives of numerical characterizations a few researches in this area have been carried out using a heterogeneous wood-cement composite. This study is based on a constructive approach using the finite volume method in order to generate a numerical model capable of reproducing;the equivalent transfer properties of a wood-cement composite. The challenge is to understand, design, and control this multiphase inhornogeneous structure and predict transfers and flows within the community in order to achieve an optimal functionality. Experimental measurements and microscopic characterization using X-ray microtomography were performed to compare and demonstrate the method validation. The comparative results demonstrate a less than 100\% deviation between the measurements and the simulations of the equivalent thermal properties. Thus, thermal conductivity and permeability, under different medium configurations, were characterized. Therefore, it was observed that these properties depend strongly on the porosity and the pore distribution in the continuous phase. Moreover, these two parameters are highly dependent on cement percentages in the structure.

}, author = {R.C. DEPTULSKI and F. MNASRI and M. EL-GANAOUI and R. BENNACER} } @article {1822, title = { Thermal building control using active ventilated block integrating phase change material }, journal = { ENERGY AND BUILDINGS }, volume = {187}, year = {2019}, pages = {50-63}, abstract = {

In the context of improving energy efficiency and thermal comfort in the building, the use of phase change materials (PCMs) is one of the suggested solutions. The proposed integration solutions concern the building envelope as well as the applications related to its operation. The study of the incorporation of PCM in the walls of the building was the subject of numerous works. However, the antisymmetric character of storing/recovering energy management in the walls is less controlled and do not fit the optimal conditions. In this study, a solution based on the direct integration of a stabilized PCM (gel) in an envelope including ventilation channels, was proposed to overcome this problem of antisymmetry storing/recovering and fitting with different fixed ambient conditions. The final aim is to develop the optimization strategy of a wall combining the heavy inertia offered by the PCM, intra-ventilation control and the contribution to air renewal energy demand.

In this context, an experimental study of a concrete block system is conducted to test the thermal response of this configuration by the application of cyclic solicitations. The comprehension of this integrated constructive solution essentially passes by the possession of validated numerical tools. For this, two models have been developed. The first model using the electrical-thermal analogy, based on an RC equivalence, is distinguished by its relative simplicity and weak time computing demand. Each of these two factors, R and C summarise the system properties and has a direct influence on the building transient simulations over a year. The second one is based on direct numerical simulation DNS of the energy and fluid flow equations using commercial code COMSOL Multiphysics. Such DNS is time consuming and could not be used to simulate over a year but aims only to validate the first RC circuit approach. A comparison of these two models with the idealised experimental data was carried out and allowed the validation of the thermal behaviour of the solution based on the integration of the PCM with core ventilation.

}, author = {A. LAAOUATNI and N. MARTAJ and R. BENNACER and M. LACHI and M. EL-OMARI and M. EL-GANAOUI} } @article {1718, title = { Effect of aligned and misaligned ventilation opening affecting energy demand and air quality in buildings }, journal = { EUROPEAN PHYSICAL JOURNAL-APPLIED PHYSICS }, volume = {83}, year = {2018}, abstract = {

This work focuses on a horizontally ventilated cavity filled with air, heated on one side wall and cooled on the floor surface. Therefore, this study has been carried out for a convective loop induced for a fixed Rayleigh number Ra= 10(6) and horizontal ventilation (moderate Reynolds number Re= 100) where the injection is either in cooperating or opposing to the convective loop. The study undertaken concerns different opening position in order to analyze the energy efficiency of such ventilation and the corresponding indoor air quality. The results obtained indicate that the natural convection and the forced flow (ventilation) play an important role in the flow structure and the mixing ability, the heat exchange (cooling need) and the temperature comfort. The optimum ventilating position is a compromise in order to minimize the cooling demand, keep the mixing ability and reduce the temperature heterogeneity.

}, url = {https://hal.archives-ouvertes.fr/hal-02076687}, author = {S. MORSLI and H. RAMENAH and M. EL-GANAOUI and R. BENNACER} } @article {1768, title = { Small to large scale mixed turbulent convection: buildings application }, journal = { INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT \& FLUID FLOW }, volume = {28}, year = {2018}, pages = {188-205}, abstract = {

The use of natural ventilation by large openings to maintain thermal comfort conditions in the premises is a concept that is perfectly integrated into the traditional architecture of countries in the Mediterranean region or in tropical climates. In a temperate climate where the architecture is not usually designed to respond to the use of natural ventilation is seasonal and is done at the initiative of the occupants by making changes in the design of their doors. The European interest in natural ventilation, as a passive building air- conditioning technology, is increasing and has been the subject of a research program commissioned by the European Community. In this work, the authors consider a part of a housing compound as a refreshing floor. This floor is maintained at a constant cold temperature, the one vertical wall at hot temperature and other surfaces are adiabatic. Various scenarios are considered for this work. Mixed convection for different boundary conditions and different configurations is carried out. In addition, an airflow is injected through a window and extracted on the opposite window. Classical conclusion and transitional value on Richardson number have been completed by the new thermal configuration with nonsymmetric thermal conditions. The complex 3D flow structure is more obvious when one of the two flows (ventilation or natural convection) dominates. However, the induced heat transfer is less sensitive to the added ventilation. In this study, the authors consider a part of a housing compound as a refreshing floor. This floor is maintained at a constant cold temperature, the one vertical wall at hot temperature and other surfaces are adiabatic.

}, url = {https://hal.archives-ouvertes.fr/hal-01724258}, author = {S. MORSLI and M. BOUSSOUFI and A. SABEUR and M. EL-GANAOUI and R. BENNACER} } @article {1661, title = { Competition between the lid driven and the natural convection of nanofluids taking into consideration the Soret effect }, journal = { INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER }, volume = {114}, year = {2017}, pages = {1341-1349}, abstract = {

Natural convection, in a shallow horizontal cavity filled with a nanofluid, is studied. The flow is driven by Lid driven convection (LDC). External applied constant heat fluxes on the bottom wall of the cavity is applied, whereas the vertical walls are subjected to variable heat fluxes. The nanofluid concentration is treated as heterogeneous mixtures with a weak solutal diffusivity. A modified formulation taking into account the physical properties (thermal conductivity, viscosity) versus on nanofluids type and concentration and the spatial heterogeneous concentration induced by the Soret effect is presented. The induced nanofluid heterogeneity can affect the heat transfer. The heat transfer increases with increase of the boundary motion. The analytical solution, based on parallel flow approximation, is found to be in good agreement with numerical solution. The existence of both natural and anti-natural flows is demonstrated. Indeed, the subcritical Rayleigh number for the onset of instability tends to disappear when the supercritical threshold is largely affected.

}, author = {F.S. OUESLATI and R. BENNACER and M. EL-GANAOUI and A. EL-CAFSI} } @article {1699, title = { NUMERICAL ANALYSIS OF HEAT, AIR, AND MOISTURE TRANSFERS IN A WOODEN BUILDING MATERIAL }, journal = { THERMAL SCIENCE }, volume = {21}, year = {2017}, pages = {785-795}, abstract = {

The present paper aims to predict the hygrothermal behavior of massive wood panel considered as bio-based building material. In this context, we developed a macroscopic model coupled no linear heat, air, and moisture transfers that incorporates simultaneously the effect of thermal diffusion and infiltration phenomenon on the building material. The model inputs parameters were evaluated experimentally according to the recognized standards of material\&$\#$39;s characterization. Therefore, numerous series of hygrothermal calculation were carried out on the 1-D and 2-D configuration in order to assess the dimensionless effect on such wooden material. Two types of boundary conditions were considered and examined. The first are at the material scale of wood drying process. The second type of conditions is at the wall scale, where the conditions of the building ambiance are considered. Moreover, the model sensitivity to the driving potentials coupling and to the parameters variability was considered and examined. It has been found that the coupling in the model had a remarkable impact on both kinetics of temperature and moisture content.

}, url = {https://hal.archives-ouvertes.fr/hal-01684849}, author = {F. MNASRI and K. ABAHRI and M. EL-GANAOUI and R. BENNACER and S. GABSI} } @article {1705, title = { Thermal effects of an innovative green wall on building energy performance }, journal = { MECHANICS \& INDUSTRY }, volume = {18}, year = {2017}, abstract = {

Green walls and green roofs are innovative construction technologies involving the use environmentally friendly materials. In addition to their aesthetical and environmental benefits, green walls have significant thermal effects on buildings and heat islands within high-density urban areas. In this paper, we study the impact of an innovative green wall system on building energy performance. These green walls have specific composition and particular geometry that can lead to higher thermal performances and therefore more significant impact on building energy performance. The development, validation and prior integration of a hygrothermal green wall model in a transient building simulation tool make possible the assessment of the energy performance of buildings when covered by green walls. The used model was adapted to be the particular forms and composition of the studied green walls. In parallel, this type of green walls has been installed on a one tenth building mockup to be experimented. The aim of the experiment is to measure the thermal effects and to calibrate some parameters of the numerical model. The results highlight the thermal benefits of this kind of green walls in summer condition. They reduce annual energy demand of building up to 37\% for hot climates.

}, url = {https://hal.archives-ouvertes.fr/hal-02113149/}, author = {R. DJEDJIG and M. EL-GANAOUI and R. BELARBI and R. BENNACER} } @article {1574, title = { Analytical and numerical solution to the convection problem in a shallow cavity filled with two immiscible superposed fluids }, journal = { INTERNATIONAL JOURNAL OF THERMAL SCIENCES }, volume = {90}, year = {2015}, pages = {303-310}, abstract = {

Natural convection, in a shallow horizontal cavity filled with two layers immiscible fluids, is studied both numeric and analytic. The horizontal walls of the enclosure are heated by the bottom and cooled by the upper by a uniform heat fluxes while the verticals one are subject to heat fluxes of variable intensity. The analytical solution, based on the parallel flow approximation, is found to be in good agreement with a numerical solution. The existence of both natural and antinatural flows is demonstrated. Indeed, the critical Rayleigh number for the onset of motion is dependent on the side heating intensity. In the case where the upper fluid is more viscous than the bottom one, multiple solutions are possible as well as the a steady states in a range of ratio of the viscosity of the fluids. The fact that one of the two fluids is more heat conductive, affect not only heat transfer generated but also the intensity of flows and the existence of the third cell where we found several solutions. The present model yields explicitly the flow patterns and Nusselt numbers in terms of the governing parameters of the problem.

}, url = {https://hal.univ-lorraine.fr/hal-01597079}, author = {F.S. OUESLATI and R. BENNACER and M. EL-GANAOUI} }