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The cost of manufacturing and electricity consumption are key considerations in encouraging the adoption of solar air heaters (SAH) in sunny and low‐income areas. These parameters can have a significant impact on promoting the use of these devices. In this study, solar air heating was designed with the objective of achieving the highest possible efficiency/cost ratio. It is a corrugated channel SAH whose structure is equipped with two barriers perforated with a sufficient number of holes for a good airflow distribution. A new model was developed to evaluate the qualitative parameters that describe the thermos‐energetic behavior of a heating system. These parameters were measured using experimental data obtained under real operating conditions. The thermal model assumes a uniform temperature for the glass, absorber, and insulation of the collector, while the temperature of the circulating air is assumed to vary linearly along the collector. To ensure that these assumptions were valid, the collector was cut into a number of 0.1 m sections in the direction of flow. By comparing the numerical results with the experimental data, the model was validated and then used to calculate the temperature profiles of the different elements of the collector, as well as to estimate the impact of certain operational parameters on its thermal performance. Relative percentage error values, between the numerical and the experimental results, of 1.7517%, 1.0750%, 0.8577%, 2.2371%, and 2.3637% for absorber plate temperature, outlet airflow temperature, useful power, thermal, and effective efficiencies, respectively, are recorded. [ABSTRACT FROM AUTHOR]

The work presented in this article proposes the design and the realization of a PWM controller, which allows the control of the power switches of DC-DC converters of discrete two-stage photovoltaic systems in series. The method employed is based on the use of two drivers by exploiting their functionalities in order to improve and control the two power switches of the discretized photovoltaic system. The proposed technique is validated by experimentation on a photovoltaic system, the upper stage of which can request a floating voltage on the MOSFET drain of up to 30V. the studied PV installation is equipped by a protection circuit block for protect the PV equipments in the event of poor connection or deterioration of elements in system blocks. The simulations and the experiments showed a good functioning of the control unit which ensured: An amplitude of the PWM signals large enough to control the power switches, optimal system operation regardless of load and weather changes and good efficiency, and protection of the installation in the event of malfunction.

Transferring images in a wireless multimedia sensor network (WMSN) knows a fast development in both research and fields of application. Nevertheless, this area of research faces many problems such as the low quality of the received images after their decompression, the limited number of reconstructed images at the base station, and the high-energy consumption used in the process of compression and decompression. In order to fix these problems, we proposed a compression method based on the classic discrete wavelet transform (DWT). Our method applies the wavelet compression technique multiple times on the same image. As a result, we found that the number of received images is higher than using the classic DWT. In addition, the quality of the received images is much higher compared to the standard DWT. Finally, the energy consumption is lower when we use our technique. Therefore, we can say that our proposed compression technique is more adapted to the WMSN environment. [ABSTRACT FROM AUTHOR]

In this paper, we present the results concerning the design, the realization and the characterization of a photovoltaic system (PV), medium power (100 W), equipped with a MPPT control, a controller battery, a system for tracking the sun and a system for the acquisition and supervision, based on a microcontroller. The experiment of each block, show that: (1) The digital MPPT control convergence instantly operating point of the PV panels around the maximum power point, independently of rapid changes in the illumination and the load, (2) Regulating the charging and discharging of batteries is carried using an algorithm including the specificities of the PV system, (3) The need for a sun tracker to increase the power supplied by the PV panels. All the results show the reliability of a complete PV system and an operation exploiting the maximum of solar energy. [ABSTRACT FROM AUTHOR]