Autonomous solar cooker with photovoltaic energy

In this paper, we propose the design and operation of solar cookers (hot plates and box ovens) using photovoltaic energy. The electrical energy to feed the thermal resistances of these cookers is provided by the photovoltaic (PV) panels, via a DC/DC power converter of Boost type equipped with a specific electronic control. The typical experimental results, during the heating of one liter of water, show, for a photovoltaic power of 600 Wp, a frequency of the DC/DC converters of 30 kHz, an illumination and an ambient temperature of the order of 998 W/m2 and 22°C, very satisfactory performances: powers at the input and there at the output of the converter respectively of the order of  476. 8 W and 465.1 W (i.e. an efficiency of 97 %), temperature of the thermal resistances of 660°C after 20 seconds, rise of the water heating temperature from 24°C to 49°C after 5 minutes and boiling temperature of 98°C after 18 minutes of heating.  All these results show the feasibility of operation of the proposed cooker and thus its use inside or outside the homes for heating and daily cooking (water, meals,…)

Studies on a multi-stage solar desalination plant (MSD)

A solar desalination system composed of an evaporation/condensation chamber formed by a lower basin and eight horizontal stages, coupled with a field of four flat thermal collectors with a total surface of 8.4 m2 and a field of panel to supply a pump, which supplies system with saline water from wells was installed in Douar Al Hamri, in the rural commune of Boughriba of the Province of Berkane and tested under the meteorological conditions of this region. A simulation model of the desalination system has been developed and validated with experimental measurements of the system. The simulation model uses a numerical solution to a set of differential equations describing the system. The objective of this installation is to produce pure (drinking) water, from a well of high conductivity (4050 µs/cm) and salt content (>2,720 mg/L), to the inhabitants, isolated and not connected to the national drinking water network. The experimental results of the MSD system show, during season of 2020, under an irradiance and ambient temperature condition of Oriental region, maximum values of the stage temperatures of  90°C and maximum production of 48 litres with low conductivity (88 µs/cm) and salt content (<0.045 mg/L).  The main objective of this pilot station in Morocco is to ensure the production of drinking water to the inhabitants of the Douar by solar energy. The modelling of these experimental results, from the thermal equations, set up during this work, shows a very good agreement between the experiment and the simulations. The analysis of all the results and their comparisons with the literature clearly show the good functioning of the MSD system blocks, set up during this work.

Operation of Photovoltaic Panels in Stand-alone Applications

In this chapter, we propose the analysis of the maximum power point (MPP) of photovoltaic panels (PV) in a renewable energy application. From the current–voltage characteristics, we deduced the MPP of a PV panel and specified the use of a power block (DC/DC converter) controlled by an MPPT control. In the case of an MPPT control of type perturb and observe, we realized the photovoltaic system that heats a photovoltaic solar cooker, taking into account this MPPT command. The experimentation of this application, during a sunny day, shows that the MPPT control carries out its role correctly, such as optimal operation of the PV panels and heating of the cooker by the maximum power supplied by the PV panels. The analysis of all the results shows an excellent agreement between the experiment and the simulation of the operation of the photovoltaic system which made it possible to operate the photovoltaic panels around their MPP, over the course of the sun. Under these conditions, the efficiency of the proposed DC/DC converter, with a power of 500 Wp, is of the order of 97%

Morphological and electric characterizations of a nanometric materialα-CuMoO4for photovoltaic application

The work presented in this publication concerns the elaboration by soft chemistry and the structural, morphological and physical characterizations of semiconductors with metallic Oxides CuMoO4. Particularly, we study the caking of powders of molybdate of copper: conventional sintering and Spark Plasma Sintering (SPS). The characterization by X-rays diffraction analyses (DRX) and scanning electronic microscopy (SEM) show that the ceramic obtained by SPS at 300°C for 5 min hasa densificationof 98.0 %, superior to that of the ceramic sintered in a conventional way (94.8 %), with a grainsize (0.2μm) significantlylower than thatobtained by conventional sintering(2.0 μm).The study of the electric properties by the method of the current-voltage measurements (I-V) of the nondoped ceramic CuMoO4showsonone hand, the semiconductor character of the material and on the other hand, a clear improvement of the thermal activationof the carriers in the case of the ceramic obtained by SPS at 300°C. The width of the forbidden gap (Eg) deducted from these measurements is 1.8 ± 0.1 eV

Proprietes electriques des structures metal/isolant ultra-mince/semiconducteur

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 78579 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Control and management of energy in a PV system equipped with batteries storage

<p class="Abstract"><em>In this paper we present a work concerning the conception, implementation and testing of a photovoltaic system that is equipped with a new concept of control and manage the energy in a PV system with a battery storage. The objective is to exploit the maximum of power using Hill climbing improved algorithm that considers optimal electrical characteristics of PV panels regardless of the system perturbation, to manage the energy between blocs of PV system in order to control the charge/discharge process and inject the energy surplus into the grid and also to estimate the state of charge with precision. Moreover, the system guarantees the acquisition and presentation of results on computer, supervision and so on. The results obtained show the robustness of the PV system, good control and protection of batteries under the maximum of energy provided by the PV panels. The state of charge estimation is evaluated by using measured parameters in real time; it shows an improvement of around 5% compared to the conventional technique.</em></p

Conception and realization of a PV system provided with a sun tracker operating at dual axis

In this paper, we present the conception, the realization and the experimentation of  a photovoltaic (PV) system provided with a sun tracker reliable and low cost operating at dual axis. The tracker's role is to orient the PV generator, whose weight may reach 9 Kg, perpendicular to the sun with very good accuracy. This tracking  based on the use of four LDR sensors, which detect the intensity of light scattered by the sun a processing unit, from  command and control (UTCC), which manages all of the sun tracking tasks (the end detection of parcours, regulation of the power supplied by the PV panels (Command MPPT), ... ). The results obtained show a significant improvement of the energy produced, compared to conventional PV installations where generators are fixed and oriented south at a  tilt 45°. During a day of operation, improvement could reach 41% and consumption of the tracking does not exceed 0.55% of the energy production produced by the PV generator (an improvement of 5 % compared to existing trackers)

Control and management of energy in a PV system equipped with batteries storage

In this paper we present a work concerning the conception, implementation and testing of a photovoltaic system that is equipped with a new concept of control and manage the energy in a PV system with a battery storage. The objective is to exploit the maximum of power using Hill climbing improved algorithm that considers optimal electrical characteristics of PV panels regardless of the system perturbation, to manage the energy between blocs of PV system in order to control the charge/discharge process and inject the energy surplus into the grid and also to estimate the state of charge with precision. Moreover, the system guarantees the acquisition and presentation of results on computer, supervision and so on. The results obtained show the robustness of the PV system, good control and protection of batteries under the maximum of energy provided by the PV panels. The state of charge estimation is evaluated by using measured parameters in real time; it shows an improvement of around 5% compared to the conventional technique.</p

Control and management of energy in a PV system equipped with batteries storage

<p class="Abstract"><em>In this paper we present a work concerning the conception, implementation and testing of a photovoltaic system that is equipped with a new concept of control and manage the energy in a PV system with a battery storage. The objective is to exploit the maximum of power using Hill climbing improved algorithm that considers optimal electrical characteristics of PV panels regardless of the system perturbation, to manage the energy between blocs of PV system in order to control the charge/discharge process and inject the energy surplus into the grid and also to estimate the state of charge with precision. Moreover, the system guarantees the acquisition and presentation of results on computer, supervision and so on. The results obtained show the robustness of the PV system, good control and protection of batteries under the maximum of energy provided by the PV panels. The state of charge estimation is evaluated by using measured parameters in real time; it shows an improvement of around 5% compared to the conventional technique.</em></p

Propriétés électriques des diodes Schottky en Polymères

Le travail présenté dans cette communication concerne la réalisation et la caractérisation électrique (courant-tension I/V) des diodes Schottky en polymère (P3OT) de type P. Les résultats obtenus montrent que les structures réalisés sont stables : après plusieurs passages I/V, les caractéristiques obtenues passent par la même courbe. Concernant le mécanisme de conduction de ces structures, nous avons montré qu'il peut être modélisé par celui des structures Schottky inorganique (Silicium) en régime direct : se manifeste le mécanisme de conduction par effet Thermoélectronique et Fowler-Nordheim. L'ensemble des résultats obtenus montre d'une part la faisabilité du processus technologique de réalisation des diodes Schottky en polymère, et d'autre part une contribution intéressante permettant une meilleure compréhension du mécanisme de conduction des polymères