Every year, more than 236,807 tons, equivalent to 30% of date-palm fruits produced in Algeria, is lost during picking, storage, and commercialization processes. Gasification of this huge biomass can generate biogas such as bioethanol, biodiesel, gasoline and other useful substances. Bioethanol is becoming the main biofuel produced by chemical synthesis or anaerobic fermentation from biomass and is significant for industrial development, investment, and use. It is eco-friendly, moderately costly and cleaner than other gasses. Actually, due to modern biotechnologies, it is possible to valorise the common date-palm waste (CDPW) by bioconversion and to commercialize them in local and international markets in the form of new products with an acceptable added value such as bioethanol. CDPW is a renewable and sustainable resource of energy that is not greatly used in industries. The date is rich in biodegradable sugars, providing bioethanol after fermentation during 72 h at 30°C in the presence of Saccharomyces cerevisiae yeast and the distillation of date's juice obtained. In the first experience, a solar batch fermenter (SBF) of 50L capacity, and a butane gas distiller using a cocotte (cooker) of 30L capacity was designed and constructed. The bioconversion systems led to the production of 250 mL/kg of ethanol at 90° after distillation of the CDPW juice at 78°. This is in comparison to the theoretical ethanol directly produced from sugar by chemical synthesis process. The 33% efficiency that was obtained appeared satisfactory and it encouraged the great scaling development of bioethanol based on CDPW biomass and other raw materials abundant in Algeria Sahara.

Modeling and simulation of mechanical structures in development phase are fundamental to optimize and improve the stability and reliability of the final product as well as to reduce the cost of prototyping and testing. Wind turbines are subject to critical loading to the centrifugal force due to wind speed and gravitational force. The present study discusses three-dimensional numerical simulations of combined Darrieus-Savonius wind turbine D-SWT for applications in urban and isolated areas for lighting, pumping water, etc. The Darrieus turbine is used to produce wind power and the Savonius rotor to start the system. Finite Element Analysis (FEA) using SolidWorks 2015 is employed to generate the geometry of the structure and SolidWorks Simulation to investigate the stability and reliability static on the structure of the D-WST built by two types of material of the blade Galvanized Steel (GS) and Aluminum alloys 1060-H18 (ALU). Mechanical parameter of the structure are calculated for critical loading conditions, including the gravity and wind pressure loading due to the wind speed of 23m/s. Simulations results indicate no structural failure is predicted for all components of the D-SWT for both materials used according to Von Mises criterion stresses and the factors of safety of the most fragile material are greater than (the unity) 1. The maximum displacements found (3.84 & 6.81mm), occurred at the tip blades (free ends levels). These displacements are accepted relatively to the structure size.

Wind and solar resources are diluted and intermittent on the earth; their combination allowed increasing their availability and stability. At great scale, the use of Solar Chimney Power Plant (SCPP) technique constitutes a promising alternative to fossil fuel for generating electrical power particularly in rich regions of natural resources such as solar, wind, terrain, built material, water…etc.). Recently, various research works investigate the design and optimization of these systems under operating conditions. The analysis of different studies carried out on (SCPP), allowed to develop a parametric modelization approach in steady state, founded on 1D heat and mass transfer inside the (SCPP) in order to describe, optimize and to assess its performances under the influence of geometric, operating and ambiance conditions using Matlab-Simulink code. From the present simulation results, the (SCPP) appeared feasible since the temperature gradient of the airflow between the inlet and outlet of the chimney attains 13°C and remains constant during operating cycle. The (SCPP) output is strongly influenced by solar radiation intensity, air heater surface, and chimney height. The solar air heater, the tower (chimney) and the (SCPP) efficiencies obtained are 22.6%, 19.2% and 2.6% respectively.

Sun-tracking system (STS) is a key factor for solar photovoltaic (PV) future and new answers for the solar market. It will expand large-scale PV projects (PV farms) worldwide, and it is possible to collect more energy from the sun. PV farms consist of thousands of STS that are subject to dynamic loads (wind, snow, etc.), vibrations, and gravitational loads. This paper presents the structural dynamic analysis of a 24 m2 bi-axial STS (azimuth-elevation) at different elevation angles based on its modal parameters (natural frequencies, modal shapes, and modal damping ratios) and dynamic performance indices (modal participation factors (MPF), forcing frequencies, and mechanical quality factors) by means of the finite element analysis (FEA). The simulation results show that the structural dynamic design of the STS meets the desired structural requirements and agrees well with structural dynamic standards (EN 1991-1-4 and ASHRAE). These results can be used for further analysis on optimal design and vibration safety verification for the bi-axial STS (PV applications).

This paper presents the now design, modeling and static analysis of a new two-axis solar tracker (Azimuth and Altitude). The tracker is an electro-hydraulic device that keeps photovoltaic panels in an optimum position perpendicularly to the solar radiation during daylight hours. The tracker of 24 m² panel’s size was designed using the SolidWorks 3D CAD software. The finite element method (FEM) is adopted to ensure the stability and the reliability of the tracker. COSMOSWorks was used to determine displacement, equivalent stress and safety factor of the tracker under its own weight and wind load critical, namely wind speed of 130 km/h. Simulation results show that the maximum displacement of the structure is 1.18 mm, the level of the maximum equivalent stress is 74.43 MPa and the safety factor is about 3. The tracker structure completely satisfies the design requirements.