EMPIRICAL MODELS FOR LOSSES CALCULATION IN A RECTANGULAR DUCT EQUIPPED BY ARTIFICIAL ROUGHNESS

The objective of this work is to find empirical models linking load losses to the geometric characteristics of artificial roughnesscalled baffles and different modes of provisions of these fluids in the vein of a rectangular channel.An experimental design was set up to measure the losses Load caused by baffles between the upstream and downstream of thechannel. The experimental measurements made have enabled us to establish empirical relationships to evaluate losses inaccordance with load losses configuration and arrangement of baffles and for different flow regimes

EMPIRICAL MODELS FORLOSSES CALCULATION IN A RECTANGULAR DUCT EQUIPPED BYARTIFICIALROUGHNESS

The objective of this work is to find empirical models linking load losses to the geometric characteristics of artificial roughness called baffles and different modes of provisions of these fluids in the vein of a rectangular channel.An experimental design was set up to measure the lossesLoadcausedby baffles between the upstream and downstream of the channel. The experimental measurements made have enabled us to establish empirical relationships to evaluate losses in accordance with load losses configuration and arrangement of baffles and for different flow regimes

SIMULATION OF A SOLAR DRIVEN AIR CONDITIONING SYSTEM FOR A HOUSE IN DRY AND HOT CLIMATE OF ALGERIA

Solar cooling technology is environmentally friendly and contributes to a significant decrease of the CO2 emissions which cause the green house effect .Currently, most of the solar cooling systems commonly used are the hot water driven lithium bromide absorption chillers. According to the operating temperature of driving thermal source, single – effect Li Br/H2O absorption chillers have the advantage of being powered by ordinary flat-plate or evacuated tubular solar collectors available in the market. The main objective of this work is to develop a computational model that allows the simulation of an hourly basis for an absorption refrigeration - single - effect used the LiBr/H2O as solution working fluid- system assisted by solar energy and natural gas as auxiliary fuel coupled with the residential building located in the hot and dry climate of Algeria. This model will be developed using the dynamic simulation program TRNSYS, considering three specifics areas of work: determination of the cooling loads for a building, implementation of the computational model for the absorption refrigeration system and the parametric optimization of components, which will make possible an approach to optimal sizing of the solar absorption system. The results of the simulation of the absorption chiller indicate that an area of 28 m2 of flat plat collectors with an inclination of 35° and 800 L for hot storage tank provides an annual solar fraction of 80% and a thermal performance coefficient COP of 0.73, getting to cover demand of air conditioning in a house of 120 m2 located in Biskra (Algeria)

REALISATION D’UNE INTERFACE DE SIMULATION DES PERFORMANCES DES INSOLATEURS PLANS

L’utilisation des énergies renouvelables comme sources d’énergie dans lesprocessus énergétiques industrielspermet de réduire la demande énergétique en matière d’hydrocarburesetla diminution des gaz à effet de serre ainsi qued’encourager l’utilisation des ressources durables en énergies propres. Dans ce travailnous nous intéressons à la valorisation du gisement solaire dans divers sites, de climats différents, par la réalisation de cet outil de simulation du rayonnement solaire, de la température ambiante et de la température de sortie de l’insolateur. Il permettra à tout utilisateur simple ou potentiel d’avoir des informations préalables avant d’entamer un projet solaire

SIMULATION DU COMPORTEMENT ENERGETIQUEDES BATIMENTS RESIDENTIELS AU SUD ALGERIEN

Le programme d'amélioration de la performance énergétique des bâtiments résidentiels obéit à la volonté de l 'Algérie,de favoriser une utilisation plus responsable de l'énergie et d'explorer toutes les voies pour préserver les ressources et systématise r la consommation utile et optimale. Au niveau national le secteur résidentiel estle secteur le plus énergivore,il représente42 % de la consommation finale.L'objectif de ce travail est de contribuer à l'amélioration de l'efficacité énergétique des bâtiments résidentiels situés au climat chaud et sec.En premier lieu un état de l'art sur le bilan de consommation énergétique au niveau national et en particulier à la ville de Biskra est donné.Ensuite et dans le but de simuler le comportement énergétique du bâtiment, on a utilisé le logiciel TRNSYS. Deux types de bâtiment ont été simulés et comparés, l'un est considéré comme étant un bâtiment de référence BR et l'autre un bâtiment basse consommation BBCdont une enveloppe isolée (murs, terrasse et vitrage).Les résultats de la simulation montrent que les besoins énergétiques en refroidissement du bâtiment BBC font quasiment le 1/ 3 de ceux du bâtiment BR et que la différence de l'Intensité Energétique IE entre les deux bâtiments est de l'ordre de 70,62 KWh/m²

Thermal energy storage using desert sand : a numerical study of the thermofluidic performances

The Thermal Energy Storage (TES) enhances the availability of renewable energy plants. It reduces the mismatch between the production and the demand of the electric energy. However, the high cost of the TES leads to a high overall cost of the produced electric kWh. In the case of solar power plants built in Saharan regions, the use of sand as the storing medium in the TES is a priori a suitable technique that can solve this problem. In fact, the sand presents good physical and chemical properties and it is locally available with a very low cost. In this paper, a numerical study has been conducted to assess the thermal and fluidic performances of a fixed bed and of a fluidized bed by using sand as storing medium. The heat is transferred to, and from, the sand by air. 2D and 3D simulations are conducted. The temperature profiles of the bed are examined as well as the storing rates. Parametric studies with the air speed and the height of the bed were considered. The results gained in this paper indicate that it is very viable and promising to integrate sand as storing media in the solar thermal applications especially where this material is plentiful.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

STUDY AND NUMERICAL SIMULATION OF SOLAR SYSTEM FOR AIR HEATING

<p>The use of solar energy in sunny countries, is an effective outil for compensate the lack in the energy, their benefits are not related only to its economic benefits but especially for the environmental protection, so we must find solutions to the problems of pollution. This work is a theoretical study of a solar flat plate collector ; air is used as the heat transfer fluid. In this study, we established in first step the calculation of solar radiation in various sites in Algeria (Adrar, El Oued, Bechar, Biskra and Tamanrasset). The second step is the parameters influence study of the sites and climate on the performance of our collector. The results obtained are encouraging for the use of this type in the heating in the winter, also it can be used in different kinds of drying.</p