Abdelhafid Moummi

Systematic forecasts of solar collector's performance in various sites of different climates in Algeria

This paper presents the results of theoretical models suggesting investigation of the performance of a solar air flat plate collector. The model can predict the temperature of the outlet air. This will be compared with the results obtained by the experimental results. The range of experimental results related to the thermal performances of plane–air solar collectors and various practical uses, inspires us to undertake this work in the context of a rational exploitation of local solar field. Indeed the setting up of a solar system to satisfy a well-determined need in a given site has to be done only after first having estimated the system productivity relative to the solar field actually available by fine weather (bright sky) or by bad days (covered sky) and then having an exact knowledge of the evolution of the climatic parameters.

Performance investigation of single- and double-pass solar air heaters through the use of various fin geometries

This paper presents an experimental comparative study on the thermal performance of the following three single-pass types of solar air heaters (SAHs): (i) without obstacles, (ii) with rectangular obstacles and (iii) with a new form of obstacles in the air flow duct. Thus, we carried out studies to compare the best system with (iiii) a double-pass flat plate collector having the same type of obstacles in order to determine the best-performing model. All collectors were designed, constructed and tested in the University of Biskra (Algeria) in a stand facing South at an inclination angle equal to the local latitude. In comparison with the recent literature, at different air mass flows, the highest efficiencies were obtained from the double-pass SAH with trapezoidal obstacles. In addition, this study has allowed us to show that the use of obstacles, in the air flow duct of the SAHs, is an efficient method to improve their performances.

Experimental study of new solar air heater design

ABSTRACT The suitable design is the most important key to a cost-effective solar air heater. Although there are many techniques that have been proposed to improve the solar air heaters’ performance by means of different turbulence promoters, they cannot ensure a compromise between the cost and the effectiveness. The aim of this study is to find simple and tolerable solution to get rid of the inconvenience resulting from the widely adopted heat-transfer-enhancement techniques by providing an optimized solar air heater design. The proposed design consists of a slightly curved smooth flow channel with an absorber plate of convex shape. A prototype of a curved solar air heater of 1.28 m2 collector area was built and tested under summer outdoor conditions in Biskra (Algeria). The performance was evaluated in terms of thermal and effective efficiency for mass flow rates of 0.0172, 0.029, and 0.0472 kg/sm2. It is observed that the overall efficiency of this solar air heater is considerably higher in comparison with the efficiency range of the conventional smooth flat plate heaters reported in the literature for similar operating conditions.

A numerical study of the phenomena of heat transfer in plane air solar collectors

To understand the mechanisms of propagation of heat in different parts of the solar air plane, we present in this work a numerical study concerning the heat exchange between the different parts of a plane air solar collector with a smooth duct. This simulation allows us to provide almost exact information. It depends on the models used for the evaluation of the losses on the distribution of temperature in the principal components of the collector in the case of a steady regime. This work is carried out in order to develop a flexible method of energy analysis which can be exploited further in comparative studies of various structural and conceptual configurations of these converters of energy.

Dynamic and thermal study of air flow control by chicanes with inclined upper parts in solar air collectors

A dynamic and thermal simulation for two-dimensional model is developed on air flow and heat transfer control by chicanes in solar air collectors. New chicane form is adopted with two parts: the first is orthogonal to the air flow direction and the second is titled (α=60°). It is apparent that the turbulence created by introducing chicanes, resulting in greater increase in heat transfer inside the dynamic air vein with a rise of 23%. The effect of the variation of the Reynolds number in the range of 100<Re<4500, on the convective heat transfer coefficient, the pressure drop and Nusselt number are analysed and have shown good agreements with the literature results. Therefore, the mass flow rates effect on the velocity magnitude, temperature and the turbulent intensity is analysed. The Reynolds number variation showed a substantial effect on the mechanism of vortex development and separation phenomenon.

Experimental investigation and exergy analysis of an air heater with a solar concentrator used for drying processes

1 Centre de Développement des Energies Renouvelables, CDER, Algiers 16340, Algeria 2 Laboratory of Civil engineering, Hydraulics, Sustainable development and Environment (LAR-GHYDE), University of Biskra 07000, Algeria 3 Laboratoire de Génie Mécanique (LGM), Université de Biskra BP 145, Biskra 07000, Algeria 4 Laboratoire de Génie Energétique et Matériaux (LGEM) Biskra, Biskra 07000, Algeria 5 Laboratoire de Génie Mécanique, Université d’Amar Telidji, Laghouat 07000, Algeria

An experimental study of a new Solar Air Heater with a Linear Fresnel Reflector

In this experimental study two solar technologies concentration and the flat plate collector were combined in one solar air heater with a Linear Fresnel Reflector (SAHLFR). A rectangular useful duct with 2.32 [m] length and 0.2 [m] width is equipped with and without artificial roughness. This roughness has wrought of steel galvanized 0.4 [mm] thickness to create a turbulent flow of air and ensure a good heat transfer. An experimental study have started to improve the SAHLFR collector efficiency especially for the drying and heating process. The measured parameters were the ambient, inlet and outlet temperatures, the absorber plate temperatures, and the solar radiation. All this measured have performed at different values of mass flow rate of air. The results show that we can go to a higher outlet temperature of air about 150 °C.