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Touafek K.,Unit of Applied Research in Renewable Energy | Haddadi M.,Polytechnic School of Algiers | Malek A.,Renewable Energy Development Center Algeria
IEEE Transactions on Energy Conversion | Year: 2011

A calorific energy is generated during the photovoltaic conversion of the solar module, which increases the temperature of the cell and will cause a fall in its electric output. This phenomenon is, on one hand, due to the partial unabsorptive solar radiation, which constituted the origin of the cells heating, and on the other hand, due to the Joule effect caused by the passage of the photo-electrical current generated in the external circuit. This heating, harmful for the photovoltaic cell output, involved many research efforts to limit its effects by evacuating this heat. There was also the idea to exploit this phenomenon by the combination of the photovoltaic module with a thermal system to form the photovoltaic thermal (PVT) hybrid collector, which will generate, at the same time, electricity and heat. In this paper, the design of a new type of PVT collector is described through its numerical modeling and experimental study. This novel collector constitutes a new technical approach to maximize the total output of conversion with lower cost compared to the traditional hybrid collectors. © 2010 IEEE. Source


Bahloul B.,University of Science and Technology Houari Boumediene | Bentabet A.,University of Bordj Bou Arreridj | Amirouche L.,University of Science and Technology Houari Boumediene | Bouhadda Y.,Unit of Applied Research in Renewable Energy | Fenineche N.,University of Technology of Belfort - Montbeliard
Physica Scripta | Year: 2011

In this paper, we aim to study the structural, electronic, elastic and thermodynamical properties of BaxSr1-xLiH3 using ab initio calculations within the generalized gradient approximation and local density approximation. In particular, the lattice constant, bulk modulus, second-order elastic constants (Cij) and electronic band structures are calculated and compared with the available experimental and other theoretical values. In addition, we have also predicted the variation of Young's modulus (E), Poisson's ratio (v), anisotropy factor (A), sound velocities, Debye temperature (D) and melting temperature (Tm) as a function of the Ba concentration (x). © 2011 The Royal Swedish Academy of Sciences. Source


Laidi M.,Blida University | Laidi M.,Dr. Yahia Fares University Center of Medea | Hanini S.,Dr. Yahia Fares University Center of Medea | Rezrazi A.,Dr. Yahia Fares University Center of Medea | And 4 more authors.
Theoretical and Applied Climatology | Year: 2016

In this study, a backpropagation artificial neural network (BP-ANN) model is used as an alternative approach to predict solar radiation on tilted surfaces (SRT) using a number of variables involved in physical process. These variables are namely the latitude of the site, mean temperature and relative humidity, Linke turbidity factor and Angstrom coefficient, extraterrestrial solar radiation, solar radiation data measured on horizontal surfaces (SRH), and solar zenith angle. Experimental solar radiation data from 13 stations spread all over Algeria around the year (2004) were used for training/validation and testing the artificial neural networks (ANNs), and one station was used to make the interpolation of the designed ANN. The ANN model was trained, validated, and tested using 60, 20, and 20 % of all data, respectively. The configuration 8-35-1 (8 inputs, 35 hidden, and 1 output neurons) presented an excellent agreement between the prediction and the experimental data during the test stage with determination coefficient of 0.99 and root meat squared error of 5.75 Wh/m2, considering a three-layer feedforward backpropagation neural network with Levenberg–Marquardt training algorithm, a hyperbolic tangent sigmoid and linear transfer function at the hidden and the output layer, respectively. This novel model could be used by researchers or scientists to design high-efficiency solar devices that are usually tilted at an optimum angle to increase the solar incident on the surface. © 2016 Springer-Verlag Wien Source


Touafek K.,Unit of Applied Research in Renewable Energy | Haddadi M.,Polytechnic School of Algiers | Malek A.,Renewable Energy Development Center Algeria
Energy and Buildings | Year: 2013

Hybrid photovoltaic thermal (or simply PV/T) collectors are devices that simultaneously convert solar energy into electricity and heat. The improving of the electrical efficiency, by reducing the photovoltaic collector's temperature, as well as taking advantage of the thermal energy produced, constitutes the basic idea in the development of hybrid PV/T collectors. A new design of hybrid collectors for air heating is presented in this paper. The theoretical study is carried out through the numerical modeling, and the results of the simulation are integrally developed; witch a prototype is realized. Experimental validation of the mathematical model as well as the study of the thermal and electric performance is detailed. The application of this new design has given a good thermal and electric performance compared to the traditional hybrid collectors. Its simplicity of implementation and its easy integration in buildings make them more competitive. © 2012 Elsevier B.V. Source


Toufek K.,Unit of Applied Research in Renewable Energy | Haddadi M.,Polytechnic School of Algiers | Mk A.,Photovoltaic Solar Energy Laboratory
Applied Solar Energy (English translation of Geliotekhnika) | Year: 2011

The combination of a thermal collector and a photovoltaic module in a single system allows for increased efficiency of the total conversion of solar energy. A synergistic effect can be obtained in a structure combining these two devices in a judicious manner to those of thermal and photovoltaic system installed separately. Production of total energy from hybrid collector depends on the input (that is to say, the. energy of solar radiation, air temperature and wind speed) and output which is the electric production and the temperature of the system. Thin production also depends on the mode of heal extraction. In this paper, an experimental Study of two configurations of hybrid collectors is described. The configuration that the absorber is made by galvanized steel and in the second, the absorber is a copper serpentine. The advantages of the first configuration are mainly due to low cost and simplicity but the second configuration has the advantage of promoting the heat transfer between cells and fluid. © Allerton Press, Inc., 2011. Source

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