Ali Malek

Experimental study on a new hybrid photovoltaic thermal collector

A calorific energy is generated during the photovoltaic conversion of the solar module which increases the temperature of the cell and will causes a fall of its electric output. This phenomenon is due, on one hand to the partial unabsorptive solar radiation which constituted the origin of the cells heating and on the other hand, with the Joule effect caused by the passage of the photo electrical current generated in the external circuit. This heating, harmful for the photovoltaic cells 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 hybrid collector (PVT) which will generate at the same time electricity and heat. In this paper we described the design of a new type of PVT collector through its 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.

Modeling and simulation of wind energy chain conversion

Abstract Alongside the substantial market for wind generation of high power systems grows smaller power (about 100 W to several kW) which is especially dedicated to remote sites. The chain of energy conversion is very different from those of great power, they are often based on the use of a three-phase alternator with permanent magnets debiting directly through a rectifier diodes in a generally electrochemical battery low voltage (12–48 V). In this article, we propose a model of the conversion chain, few conventional, for the estimation of energy production.

Predict system efficiency of 1 MWc photovoltaic power plant interconnected to the distribution network using PVSYST software

This research is a concept study for a photovoltaic power plant on an Algerian site, this plant is connected to the electrical distribution network of low or medium voltage. It follows that the study of system simulation in its entirety, would be used for this purpose the computer software PVSYST. Our work involves the design of 1 MWc photovoltaic plant in Aïn-melh Msila where there favorable weather conditions. For system efficiency we compare between structure with a fixed tilt and structure with Seasonal tilt adjustment. The results show that for fixed tilt there is a production of 1805 MWh/year injected into grid with specific energy yield, 1744 kWh/kWc/year and performance ratio, 77.8 %, as for Seasonal tilt there is a production of 1893 MWh/year with specific energy yield, 1829 kWh/kWc/year and performance ratio, 77.8 %. This will allow us recovery about 5% of production compared to fixed tilt plane.

Generation of solar irradiation maps for various applications under Algerian clear-sky conditions

ABSTRACT The present study deals with drawing solar irradiation maps for Algeria using the r.sun solar clear-sky model. In addition to the mapping of beam and global solar irradiation, the district potentials for concentrating solar power designs, solar photovoltaic technologies and water heater systems are also assessed. The program was developed using C language. The developed program is in the position to calculate the different components of solar irradiation based on the r.sun model. To improve the accuracy of irradiation estimates, we have used one-arc-minute digital elevation model, in order to consider the topography and elevation effects associated with 1.85 km step Linkes turbidity maps as input to the program. The results reveal a high potential of solar irradiation over the entire Algerian territory, especially in the Saharan regions. Further, it was also found that the solar irradiation distribution was influenced by the topography and climatic conditions throughout the country.

Energetic and exergetic evaluation of solar box cooker in Algerian climatic conditions

This paper deals with thermodynamic analysis, which constitutes an alternative approach to evaluating the performance of solar cookers. In this experimental setup, a family–type box solar cooker (SBC) with an inclined aperture area was designed and tested during clear days of months May to June in Algerian climatic conditions. The energy and exergy outputs for the SBC both without and with one reflector were in the following ranges, respectively, during the experimental period: 0.2–29.3, and 0.03–47.64 kJ as well as 0.03–1.92 kJ and 0.02–2.12 kJ. The energy and exergy efficiency for the SBC without and with one reflector was 13.6%, 16.2%, 0.73%, and 0.90% respectively, during the experimental period. The maximum daily exergy efficiencies of the SBC were 1.8% and 2.5%. Thus developing a SBC with one sun–facing reflector (booster mirror) can improve the efficiency of the cooker.

Feasibility Study of a Novel One-Axis Sun Tracking System with Reflector Displacement in a Parabolic Trough Concentrator

The size of parabolic trough concentrators limits the mechanical sun tracking system’s solution. Generally, concentrating collectors use only one-axis or two-axis sun tracking; the sun’s position changes hourly; hence, the solar collector should be continuously adjusted in order to produce the maximum power. Single-axis tracking systems are considerably cheaper and easier to construct, but their efficiency is lower than that of the two-axis tracking systems. In this paper, we present a study that confirms the feasibility of a novel one-axis sun tracking system with reflector displacement in order to minimize the optical losses caused by the cosine effect in the small parabolic trough concentrators. Optical and thermal simulations are performed to prove the efficiency of the novel system by comparison between the two cases, with reflector displacement and the ordinary system—the results are very interesting. We have proposed a novel sun tracking system with a good annual efficiency.

Generating Temperature Maps of a Solar Receiver for a Domestic Parabolic Concentrator for Cooking Purposes Under Algerian Environment

Knowledge of solar residential devices’ thermal performance is necessary in order to optimize their output. This requires a database of solar radiation for locations for which the system is being installed. In this regard, temperature maps are generated for a realized parabolic solar cooker using an improved solar radiation model for 48 cities in Algeria. The maps are drawn for two cases: clear and cloudy skies in winter and summer seasons, which allow comparison between cooker performances. The developed approach consists in converting the obtained results from optical simulation to thermal values based on Stefan-Boltzmann law. Experimental data for receiver temperatures and solar radiation measured at Ghardaia city in December were used for validation. It was found that cooker temperature values obtained from the measurements and that estimated using the proposed approach were in good agreement. The mapping results indicate that the realized cooker is efficient in all the country throughout the summer season with temperatures exceeding 110 °C. The use of the cooker is reduced by going in South to North regions during the winter months, depending on the amount of solar radiations received. Nevertheless, the major area of the country is favorable for the use of the cooker during this period of the year even when the sky remains cloudy.

Chapter 2.18 – Integration of Reflectors to Improve Energy Production of Hybrid PVT Collectors

Abstract The idea of making the photovoltaic module and thermal system in a single collector is important. We obtain by this combination the hybrid photovoltaic thermal (PVT) collector. A hybrid PVT collector can directly convert solar energy into electrical and thermal energy. This generation allows, on one hand, the increase of the electrical efficiency of PV cells through the decrease in its operating temperature and, on the other hand, the increase of total production of solar cells by reducing heat loss. In this work, we improve the electrical and thermal production of the hybrid collector by incorporating metal reflectors. Reflectors reduce reflection losses, which are generally very large. We made a prototype of this hybrid PVT collector with reflectors and a measurement companion was conducted. The studied hybrid collector was placed on the same structure as a conventional photovoltaic module of the same dimensions in order to compare their energy performances. Integration of reflectors reduces reflection losses and the total energy production of PVT collector will be improved. The electrical power of the hybrid collector with reflector has been increased compared to the PV module because the hybrid system contains a cooling system and, in addition, a reflector improves electrical and thermal efficiency.

Correlation of hourly diffuse fraction of global horizontal solar radiation in Tamanrasset, Algeria

In order to evaluate the energy production of a solar system, the tilted global radiation is needed. Generally, only the global horizontal radiation data are available. To calculate a tilted global radiation, it is necessary to estimate the diffuse or the direct component of the horizontal solar radiation. In this article, a statistical procedure has been employed to develop correlations between the hourly measured of global radiation on horizontal surface and its diffuse component. In this context, the present work compares nine models for estimating diffuse fraction, using a 10 years data archive (1996–2005) of hourly global and diffuse solar radiation obtained at Tamanrasset meteorological station. After a first comparison of these nine models, three better performing models were selected for a more detailed analysis. The accuracy of the candidate correlations are performed in terms of the two widely used statistical indicators, MBE, RMSE and t-stat was also introduced. Thereby, new correlation coefficients are established taking into account the local data. The results suggest that some models can improve more accurately, by calibration procedure, the performance of the predictive models.

Outdoor performances of four photovoltaic technologies under four typical meteorological conditions

We present a comparative study of the behavior and performance undervarious weather conditions of four PV modules of different technologies recorded in four typical daysin summer and winter. The study is based on the simultaneous and continuous testing of PV modules under natural conditions of a site located in a coastal area of southern Mediterranean. We essentially interested to the fill factor, the conversion efficiency and the energy performance. A brief description of the experimental set up and the originally method is given after the introductive paragraph. All obtained graphical results allow, at first, the validation of the approach and at second, point out that the daily evolution curves of the fill factor and the efficiency of the PV modules adopt different paces depending on the PV technology. In addition, the results of the energy study showthat the performance ratios of the different technologies aredifferently influenced by weather environment and seasons.