ICREEC 2019

District Heating Networks are an economically efficient way to decarbonise our heat supply by integrating a higher share of renewables into these networks. This paper provides an overview of utilizing solar energy in district heating networks. In particular solar thermal as well as photovoltaics and central options as well as decentral ones are discussed. Although the current use of photovoltaics in district heating networks is limited, the decrease of module prizes and the increasing need for coupling the electricity with the heat markets make it an actual field of research and application. A showcase of an existing district heating network combining all four options for integrating of solar energy is presented.

Energy saving and environment protection constitute fundamentals of the modern energy efficiency concept. Following the Algeria program on renewable energy and energy efficiency dictated by its energy transition policy, it is expected that 40% of electricity production will be from renewable energy source by 2030. This paper accompanies this policy with respect the energy efficiency concept. This is why this experimental work deals with design, build and study of a friendly environmental solar collector based on the high-density polyethylene (HDPEBIO) from vegetal origin as heat absorber. This material is commonly used in a variety of industrial applications due to its low cost, ease of use, water barrier properties and chemical resistance. However, this material is sensitive to oxidative aging and investigations must be achieved to predict its durability. In this context, the HDPEBIO used in the experiment is characterized to confirm its role as a heat absorber. The objective of this work is to contribute to a better understanding of the mechanisms involved in the influence of PEHDBIO that leads to its use as heat absorber in the solar collector. Comments on this innovative design and performances of the studied solar collector are presented and the obtained results are encouraging: Use of biodegradable materials in the solar collector is an original idea, a solar collector is performed and improved by 50% using chicanes.

In this study, experiments are performed to investigate the coupling of thermoelectric module and rectangular fin heat sink subjected to an impacting air jet for cooling desktop microprocessors. A controlled thermoelectric test system was conceived and performed for this purpose. The control of the thermoelectric forced air combined cooling system was designed on the basis of electronic Arduino card. The proposed thermoelectric forced convection cooling combined system was compared with the conventional forced air cooling technique. Three electrical powers for the heat source (CPU) were adopted and compared in this experimental study: 60, 87 and 95 W. Performance of thermoelectric cooling module with three preset temperature was experimentally investigated below diverse working conditions. Effects of thermoelectric input current and air jet velocity on the case temperature (Tcase) were analysed. The thermoelectric cooler had a considerable effect on the cooling of the CPU. However, the consumption of the energy was also augmented. Experimental results indicated that the cooling effect improved with increasing of thermoelectric operating current. However, Temperature of the heat source increased with high power input of the CPU. For a power input of 95 W of the CPU, the Tcase was maintained under 50 °C with thermoelectric input power of 45 and 5.8 W for the fan, giving improvement around 15% comparing to conventional forced air cooling.

In this work, a thermoelectric refrigerator is experimented at economic mode working on reduced voltage. The aim of this study is show the performance of a refrigerator alimented with tension lower than 12 V. In this study, we realized a thermoelectric refrigerator in the center of renewable energy CDER at Algiers. Multiple test was done regarding the optimization of energy consumption and achievement of lower temperature possible. The thermoelectric module TEC1-12706 is used for cooling. This TE module can achieve the maximum of efficiency when it function with a tension of 15 V. In our experimental study, we aliment the TE module with a tension of 9 V, the result show that the temperature of 0.5 L in the refrigerator was reduced from 26 to 18 in two hours and the coefficient of performance COP is equal to 0.45. In this work, a thermoelectric refrigerator was manufactured and tested in the laboratory. The experimental study shows that its efficiency is relatively acceptable and that the prototype can operate even at low voltage. At a voltage of 9 V, the COP remains above 0.4 and the temperature in the cooler box is slightly below 14 °C.

This numerical study deals with the evolution of a buoyant axisymmetric thermal plume issued from localized source in enclosure. The geometry configuration and the physical conditions in the confined space are the same as those chosen by Abdalla et al. (Eng. Appl. Comput. Fluid Mech. 3(4):608–630, [1]). It is aimed to analyze the influence of the natural displacement on development of thermal buoyant plume in a room connected to the exterior via high and low openings. It is sought to find the critical height at which stratification disappears when varying the airflow rate value. The buoyancy driven natural ventilation in an enclosure is modeled using the ICEM-CFD software11. The numerical results are obtained for two turbulence models based on Reynolds-Averaged Navier-Stokes (RANS): standard k-ε model and SST model. The results consistency is checked by comparisons to experimental and theoretical data. It is found that before equilibrium, ventilation velocity causes a transitional and turbulent mixing. The steady state is reached when air stratification is fully established leading to interface appearance separating the dense fresh air from the light warm buoyant air in lower and upper layers respectively. Furthermore, it is noted that the interface height is independent from the thermal source strength but depends strongly on the supplying fresh air velocity.

In this work, through central composite design, the Response Surface Methodology (RSM) has been adopted to develop an empirical model to describe the effective moisture diffusivity versus the drying conditions (air temperature, velocity) and slices thickness. The instantaneous effective moisture diffusivity estimated by the inverse method based on experimental drying kinetics data for thin-layer of pumpkin slice during hot air forced convection. A range of air temperature (40–80 °C), air velocity (2–15 m/s) and slices thickness (0.4–1.4 cm) were tested. The relationships between drying conditions, slices thickness and effective moisture diffusivity were determined. The results obtained following of the efficient moisture diffusivity tests show good agreement with the predicted values. The mentioned thin-layer drying empirical model comprise the drying conditions and slices thickness can be applied in drying process simulation of pumpkin slices in a forced air convection dryer. Using diffusion model included the drying conditions and slices thickness for modeling moisture diffusivity of pumpkin slices during convective airflow drying is very significant for a better understanding development of the drying process through the obtained results on 3D, 4D surfaces and contours. An experimental design according to the central composite design (CCD) has been constructed for investigating the air temperature, velocity and thickness influences on effective moisture diffusivity. Results illustrated by the plots show that the second-order polynomial model provide an adequate description of the responses of effective moisture diffusivity in hot airflow drying processes of diffusivity of pumpkin slices in the experimental ranges.

Natural ventilation is essential for buildings, offices and dwellings occupants’ thermal comfort and good living conditions. Also, for good production in greenhouses. Earth to air heat exchanger is a renewable source based on geothermal energy of the earth. Many working parameters affect earth to air heat exchanger thermal performance were studied: pipe burial depths, length, diameter, inlet air velocity. In the present paper, an experimental investigation of EAHE hygrometric-thermal performance with two working regimes: first work naturally with zero energy consumption and the second regime with fan (33 W). EAHE with zero energy consumption was able to create 2 working modes: heating by rising the outlet air temperature by 8 °C (between from 17 to 7 h), reduce 12 °C in cooling regime (From 8 to 16 h), and rises relative humidity by 45%. EAHE with fan provide only a rise in outlet air temperature by 12 °C. In addition, relative humidity rises by 20%. The Obtained results confirm the capacities of EAHE to contribute in thermal comfort assessment not only for cold season but also across the year with less or no energy consumption.

The purpose of this work is to improve the efficiency of a photovoltaic solar panel with water cooling system circulating along the back side of a PV panel. The numerical simulation was done on CFD code, the effect of water flow rate and the ambient air temperature on the conversion efficiency of the cooled PV panel were discussed. The results showed that at a flow rate of 100 g/s or more, the average temperature of the PV panel stabilizes, the distribution of the temperature field on the cooled solar panel with a water flow rate of 100 g/s is almost homogeneous over the entire solar panel, with the exception of the fixing zone of the electrical box which prevents the evacuation of the heat absorbed by the silicon, which raises the panel temperature locally. The results show that is enough to use 100 g/s of water flow rate to ensure a sufficient cooling. For air temperatures of 25, 35 and 45 °C, this cooling technique has improved the efficiency of the solar panel by 24.25, 28.92 and 33.92%. Concerning the junction box, which is often neglected, it has been shown that it affects the distribution of the temperature field of the PV panel and constitutes a localized area that can significantly alter the performance of the solar panel.

Response spectral analysis is obviously the most considerable experience in solar cells characterizations. However, it’s proportional to the photonics luminosity function, also known as «Quantum efficiency». In process characterization system, the monochromatic light source is considered the crucial element of the spectral response measurement system. In this work, an adapted and improved automatic system, to measure the external quantum efficiency (EQE) of solar cells based on an ATMEGA328, has been designed. For this purpose and in order to perform different electro-optical measurements to assess very low current signals, a monochromator has been automated and synchronized. Moreover, a Graphical User Interface has also been developed in order to make all the procedure easy to operate. Spectral response of different samples of silicon has therefore been characterized and assessed.

In order to improve the performance and solve the problem of integration of renewable electrical powers from a photovoltaic park at the peak time, optimal production management as well as synchronization with the increase in normal consumption, not only solve the droop voltage but also minimizes the cost of producing electricity from natural gas. Using software designed and developed, the load curve for a duration of 16 h gives the objective function the set point to find the improved voltage solution and the optimal location for reactive compensation in a real electrical network. This planned solution supports the sustainable development on the radial network 225 kV of Saida-Bechar region, and increases the stability margin for the five substations positions to study in N and N-1 situations. Analysis techniques, modeling and control system are studied and confirmed by exploiting the advanced numerical simulation. In this contribution, we studied the voltage drop in remote stations due to the high electrical load, we have solved the problem of voltage drop by local reactive compensation and the use of active power from photovoltaic farms in order to relieve and reduce the production costs of the gas turbine in bus 15. Finally, a reduction of 19.23% in the total active losses of the electrical system and an optimal location of the bank of capacitors from 5 Mvar to bus 12.

Photovoltaic (PV) energy system has considerable focus during the last decade. PV is a very attractive source of renewable energy since it’s an inexhaustible source, free and clear. A lot of paper has been focused to the optimum exploitation of the PV energy in order to maximize its efficiency. MPPT based on Fuzzy logic controller is applied in this paper in order to accelerate the reaching of maximum PV power. The principal purpose of the paper is the improvement of conventional direct power control (CDPC) performance applied to grid connected photovoltaic system. In this technique, the selection of the switching state vectors of the inverter is based on the errors between the instantaneous reactive and active powers and the respective reference quantities applied to hysteresis comparators. The output of these controllers in combination with the located sector, constitute the three inputs of CDPC table. In this paper CDPC is improved using fuzzy switching table for the selection of the optimal voltage vector position namely fuzzy direct power control (FDPC). The objectives are the reduction of harmonic of grid current, the reactive power compensation and the injection of maximum PV power into the grid. In order to evaluate the fuzzy DPC performances, the global studied system is modeled and designed in MATLAB/Simulink; the obtained results show that the active power is perfectly tracked using MPPT fuzzy controller and the reactive power tends toward zero with power factor close to unity. The grid phase current waveform is sinusoidal with THD of 0.25%.

The Solar power plants with parabolic trough collectors (PTCs) represent more than 92% of the solar thermal power plants currently in operation. It is also the most suitable technology for most plants under construction and planned [1]. The present study evaluates the thermal performance of LS-2 parabolic trough collector of Solar Electric Generating System (SEGS VI) plant. A thermal model is developed for the solar receiver based on comprehensive energy analysis. The model has been validated with the experimental data from Sandia National Laboratory. Besides, the predictions from the model were compared with the published modeling studies (both on sun and off sun tests have been considered). In all cases, the results of the developed model show a good agreement with the experimental tests and the prediction results of the other models. Particular interest has been given for the impact of the glass cover diameter on the efficiency of the solar receiver.

As energy needs increase and fossil resources decrease, the development of grid-connected photovoltaic energy is becoming an important part of the energy mix in the majority of countries. In this article, our attention has been concentrated on a strategy to control and interface photovoltaic power injection systems to the grid without batteries in order to make a significant and reliable contribution to sustainable energy supply and further improve the performance and stability of the power system. Different control mechanisms are considered in power flow management, maximum power point tracking (MPPT) for a three-phase photovoltaic inverter connected to the grid, PLL design standards (Phase Locked Loop), the current and voltage regulator VDC are also presented. The simulation results demonstrate the ability of the proposed control systems to control the energy flow, ensuring a good transfer of all maximum power to the grid.

In this article, we study a supercritical mixture model enclosed in a rectangular cavity. The mixture is composed of two elements: the first is supercritical CO2 and the other is naphthalene. This article aims to study the cavity confinement effect on the mixture and the mass transfer adsorption with a heating plate and an adsorbent at the lower limit. The mathematical model used is based on the solution of the Navier-Stokes equations, associated with energy and mass diffusion equations, including the additional Peng-Robinson equation of state. These equations are solved under the assumption of a low Mach number. Under high heating of the lower plate, the results show an influence of the cavity confinement on the adsorption of the mixture and the mass transfer. Thus, an important cavity confinement for heights up to 0.25 mm leads to an increase in mass transfer. The results also showed that the convection flow is less intense and leads to an adsorption profile less homogeneous.

In this paper, the effect of stratification and integration of the storage tank of an SDHW, a storage tank containing the system behavior is analyzed with the storage tank under different thermal stratifications. There are many different types of solar collectors, but all of them are constructed with the same basic premise in mind. In general. Get simulated solar collector results By simulating (collector with surface of 2 m2 and a storage tank of 300 L), operated in Oran (Algeria), A solar collector is a device that collects and/or concentrates solar radiation from the Sun. These devices are primarily used for active solar heating and allow for the heating of water for personal use. These collectors are generally mounted on the roof and must be very sturdy as they are exposed to a variety of different weather conditions. The use of these solar collectors provides an alternative for traditional domestic water heating using a water heater, potentially reducing energy costs over time. As well as in domestic settings, a large number of these collectors can be combined in an array and used to generate electricity in solar thermal power plants. What we do in this research is to analyze the temperature inside the tank and this taking into account the changes in the temperature that come in touching the stratification of the tank. This study gives us the ideal way to obtain good results for the system by studying nodes.

This work aims to validate an analytical calculation computer programming for a flat plate thermal solar collector with experimental results. For this reason, an experiment is carried out on a flat plate thermosiphon solar water collector with closed circulation considering the weather conditions of the Renewable Energy Applied Research Unit (URAER) of Ghardaïa located at the south of Algeria, where the outdoor test is done. The analytical calculation computer programming is based on iterative loops by introducing experimental data of the global solar irradiation and the different measured temperatures of the collector as initial conditions. The calculated results show a good agreement with the measured results. The average error associated with the calculated absorber temperatures for both the clear and partly cloudy day is less than 10%. The proposed computer program may be a useful tool for the optimisation of thermal performance of a flat plate collector under several climatic situations.

Based of the difference of climatic conditions, the efficiency of solar power plant varies from one region to another; thus, a specific design is required for different locations. Solar chimney power plant (SCPP) consists of a vertical cylinder surrounded by transparent collector. The air trapped between the collector and the ground is heated by solar radiation. Hydrostatic pressure difference between the base and the top of the chimney draws air upwards with a speed that can launch a turbine driven generator located at the base of chimney. A prototype of (SCPP) in which the air temperature and velocity were recorded as a function of meteorological parameters was installed at Ouargla University. The chimney’s height is 6 m with a diameter of 0.16 m; the collector of 16.54 m2 of area is covered with plastic with four air inputs and 0.2 m high at the entrance with tilt angle of about 6° compared to the ground. The Best results are obtained on August 15th, 2016 at 13:00 h: the air velocity was 3.1 m/s; the temperature at the collector outlet was 63 °C. Where the climatic parameters were 994 W/m2, 40.5 °C, for solar irradiance and ambient temperature respectively.

The energy of sea waves is one of the Renewable Energies. The Wells turbine uses the airflow produced by the pressure change inside the oscillating water column. A visible radial drift from the main flow occurs downstream of the rotor is noticed in the turbines wells with a constant chord length of the blade. Indeed, a blade chord linearly increasing with a radius is proposed in order to minimize this phenomenon and to increase the local coefficient of lift of the blade. In this context an investigated experimental and computational method are carried out to analyze the performances of two types of Wells turbines, one with a constant chord blade (rectangular-shaped blade) and the other with the blade’s agreement increasing linearly (Swept blade). The results obtained show an improvement in the performance of the Wells turbine with a swept blade. The analysis of the obtained results shows clearly that the characteristics of the Wells turbine with sweep blades are highest.

The objective of this work is to analyze a thermal behavior of a bare plate sun-powered collector coupled with Compound Parabolic Concentrator (CPC), considering solar data of Tlemcen. To carry out this work, a program in a MATLAB environment has been developed. The nonlinear mathematical equations coupled with the boundary conditions of this problem are solved numerically. A discretization of the systems of nonlinear equations with finite difference, as well as a solution by the method of Newton-Raphson was adopted. A parametric study was performed, taking into account the effect of: CPC concentration coefficient, mass flow rate and air passage depth on collector performance coupled with a CPC either glazed or unglazed.

Since the advent of thin layers, the efficiency of manufactured photovoltaic cells continues to increase. In addition, these new materials have many advantages over crystalline silicon, such as absorption, malleability and lightness. Our study focused on a model of photovoltaic cells with multijunction. Our goal is to model, simulate and optimize this cell, in order to derive the best characteristics for the manufacture of solar cells. We have studied and modeled the triple junction (a-Si:H/μc-SiGe:H/μc-Si:H) by the Silvaco Atlas simulator. This cell was created using the actual solar cell parameters documented in different papers. To reduce manufacturing cost and improuve conversion efficiency.

In this paper, we have presented a proposed size optimization of the PV modules by selection various types of the PV modules with their cost, finally for choosing PV array at lower cost by using the MATLAB software. Mathematical approach was presented for optimal sizing of PV system components in addition to the total capital cost of the system. As a result, the system composed of 8 polycrystalline solar modules that yields the most cost-effective system among the 9 considered systems, so the optimized PV array size is 2.24 KWc with the cost of 1984$. Our results are very encouraging as they show us the significant improvements in photovoltaic performance.

Electrolysis of alkaline water is an electrochemical process that produces hydrogen and oxygen by oxidation of water at anode and reduction of proton at cathode. These two gases are used as fuel in fuel cells, in particular Alkaline Fuel Cell (AFC). Potassium hydroxide solution is used as electrolyte and platinum as catalyst in anode and cathode. The chemical reaction taking place inside the cell, is the recombination of both gases to yield water, electric energy and heat energy. One of the major challenges for the proper functioning of the fuel cell is discharging water and heat that can damage the electrolytic solution. Therefore, it is essential to master the phenomena of mass transfer of water that operates within the fuel cell, and the optimum temperature of the inlet gas, knowing that fuel cells typically operate in isothermal conditions. The modeling of these phenomena and the real-time simulation of the main factors involved in the process can be investigated in order to ensure the good cell efficiency. The influences of current density, moisture and gas initial concentration of potassium, were observed the amount of water produced and evaporated within the cell.

Transport sector is highly dependent on oil and it is responsible for the emission of significant quantities of greenhouse gases. In order to reduce the dependency on fossil energies and reduce greenhouse gas emissions, Algeria has embarked on an ambitious program for the production of renewable energies. In this context, bioethanol represents an excellent economic and ecological solution. It is produced by alcoholic fermentation from different substrates rich in simple or complex sugar. The production from biomass rich in simple sugars is the easiest method since it does not need any pre-treatment. However, this process is excluded because all used substrates are basic food products. The second way of using non-food substrates rich in complex sugars would be the most suitable, but the production process is more complex because it requires pre-treatment and hydrolysis to release sugars. This paper describes the different methods of degradation of cellulose contained in waste paper. Office paper was collected and hydrolysed according to two methods, the first biological using a fungal enzyme, the second thermochemical using diluted sulfuric acid at high temperature, the two hydrolysed solutions were analysed by HPLC to measure released glucose, and the results showed that the thermochemical method is better by releasing twice the sugar released during biological hydrolysis.

In this numerical study, the effect of hydrogen on methane combustion for swirled, turbulent diffusion flames (100% CH4, 70% CH4 + 30% H2, 50% CH4 + 50% H2, 30% CH4 + 70% H2 and 100% H2) is presented. Local mean gas properties (NO and temperature) are predicted by solving the appropriate conservation equations in the finite volume form with the corresponding boundary conditions. The k-ε two equations turbulence model is employed to describe the turbulent nature of the flow. A five-step kinetic model is assumed to govern the reaction mechanism for pure methane and pure hydrogen using the eddy dissipation concept model for description of the combustion process. The principal objective of present study is to predict the chemical compositions and then examine the validity of the mathematical models for gas turbine combustor problems. The second objective is to discuss the consequences of hydrogen addition on the emission of gas turbine can-combustor chamber. Numerical investigation offers an improvement in the analysis and design of the gas turbine can-type combustors.

A microbial fuel cell (MFC) is a device that converts organic matter to electricity using microorganisms as the biocatalyst [1]. It was demonstrated that it was possible to produce electricity in a MFC from domestic wastewater, while at the same time accomplishing biological wastewater treatment (removal of chemical oxygen demand; COD) [2]. It has been recently proved by Ketep et al., that the use of secondary biofilms has slightly improved performance of microbial fuel cells and confirms the good results obtained with paper effluents, in terms of current densities and COD abatement [3]. In our experiments, we showed also the thicker the biofilm layer, the less time and inefficient the electronic transfer to the anode, hence the need to replicate the electro-active biofilm on a new electrode and in a new leachate. This has increased bioenergy significantly and without much latency. The electrochemical characterization in terms of cyclic voltammetry and impedance spectroscopy confirms this phenomenon with oxidation current peaks and charge transfer resistance.

Microbial Fuel Cell (MFC), an emerging energy device that produces sustainable bio-energy and treats wastewater and industrial effluent. The MFC consists of two compartments separated by an ionic exchange membrane. In the anolyte, the electro-catalytic biofilm formed on the anode, degrades the organic matter into electrons and proton. Whilst in the catholyte, the cathode reduces dissolved oxygen. The carbon based material usually used at the anode because it is biocompatible and chemically stable in the electrolyte. In order to increase its active surface, its modification with conducting polymer can increase the current density produced from MFC. Besides, the materials based on carbon and graphite are widely used as cathodes, but they should be enriched with noble metals necessary for the catalysis of the electrochemical reaction. In MFC, the polymer ionic membrane can affect significantly its performance. In effect, various parameters such as membrane internal resistance, pH splitting, oxygen diffusion, and substrate loss and bio-fouling, have been investigated. In addition, the slow transfer of proton at neutral pH, creates pH gradient at electrodes. Thus, the accumulation of protons at the anode causes acidification slowing oxidation activity. Conversely, the weak proton availability near cathode reduces the rate of cathode reaction. The use of proton membrane can replaced by an anionic membrane. The adjustment of pH in anolyte and cathode compartments, influence the cell voltage. The highest value was obtained with anionic membrane.

High-density hydrogen storage is a significant challenge for stationary, mobile and transportation applications, so the storage in solid materials remains the safest way. By performing the first-principles calculations within the generalized gradient approximation (GGA) and using the pseudo-potentials and plane waves based on the density-functional theory (DFT), the effect of zintl phase hydride SrAl2H2 on the stability of the magnesium dihydride compound (MgH2) is studied for an application in the field of hydrogen storage in solid materials. Their crystal structures are known and occurs in a trigonal and tetragonal respectively. Therefore; we investigated the enthalpy of formation for three reactions between MgH2 and SrAl2H2 compounds by calculating the total energies of MgSr and SrAl2 compounds. These last compounds crystalize in cubic and orthorhombic structure respectively. We also investigated the structural and the electronic properties of these compounds and discuss the chemical bond nature using total and partial density of electronic states. Our calculated results are generally in good agreement with theoretical and experimental data.

Biological Fuel Cell (BFC) is a device that converts chemical energy into electric energy by using a biological catalyst such as enzyme, microbe, bacteria, etc.…, and a fuel. Although enzymes and microorganisms are highly efficient biocatalysts. The microbial desalination cell (MDC) a newly developed technology, integrated the Microbial Fuel Cell (MFC) process and electro-dialysis (ED) for wastewater treatment, water desalination and production of renewable energy. The cell developed herein, was composed of two compartments: anode and cathode compartments separated by a cation exchange membrane. The biocatalyst was either on the electrode and suspended in solution. The anode was in general a carbon-based electrode, while the cathode was stainless steel plate. The connection between the two electrodes via an electrical resistance allowed the flow of electrons from the anode to the cathode through the external circuit. This flow was compensated by the flow of ions through the internal circuit. Though it was relatively weak, the produced bio-energy was always enough to feed low energy devices. We have demonstrated herein the potential energy for the treatment of a wastewater. We have proved the degradation of organic matter using the bio-film, by measuring the abatement of Chemical Oxygen Demand (COD). Besides, we have eliminated the residual heavy metal traces using by electro-dialysis. In effect, we used the bio-energy produced by the (BFC) to feed the three-compartment electro-dialysis cell (EDC). Compared to electro-dialysis, our results proved the possibility to recover metal traces at approximately the same rate of abatement, using this novel biological device.

Hydrogen storage is a great challenge for material scientists to overcome for on-board applications. Current storage methods (e.g. gas/liquid form) and materials (e.g. metal or complex hydrides) are far from being practical which requires exploration of new materials. Computational methods such as density functional theory has been proven to provide extensive structural, physical and mechanical properties as well as analyzing stabilities of compounds without complexity and cost of any experiments. In this sense, this study adopts density functional theory in order to suggest and thoroughly investigate new type of perovskite materials for solid state storage of hydrogen. SrAlH3 perovskite hydride is chosen and investigated using density functional theory in terms of ground state properties, electronic, chemical bonding properties for solid state storage of hydrogen. Electronic band structures and their corresponding density of states of compounds are obtained. The results indicate that the compound is mechanically stable and has semiconductor nature with gap energy equal to 0.6 eV. The bond chemical nature was analyzed using ELF combined with total and projected DOS.

Following their successful use as novel bioanodes in Microbial Fuel Cells (MFCs) [1], Lamellar Double Hydroxides (LDH) were tested as promising cathodes for reducing electrons in the presence of dissolved oxygen. The biofilm on anode, allowed oxidation of organic matter, yielding electrons and protons. The electrons circulated in external circuit, whilst the protons circulated in internal circuit, crossing a separator between the anolyte and catholyte. The nickel-aluminium LDH material was synthesized and added by deposition on Carbon Felt fibers (CF). It was then tested as cathode in the MFC. The electrochemical performances of the material were characterized by cyclic voltammetry (VC) and electrochemical impedance spectroscopy (EIS). Moreover, the MFC performance was evaluated from its Coulomb Efficiencies (CE). Two CEs were calculated graphically from the integral of the voltage between initial and final times, i.e. the area of the domain delimited by the representative curve, the abscissa and the vertical lines. One CE was calculated over the whole voltage curve and another from the triangular peak resulting from the addition of the substrate. It was revealed that this electrode allowed much oxygen reduction and therefore much electrical energy than that using non-modified cathode with the MFC inoculated with a fruit peeling leachate. In comparison to enzymatic fuel cell [2], it seemed to be relatively lower. However, the biomolecule (enzyme) is more expensive and difficult to handle experimentally. Thus, the low-cost biomaterials (CF) used in the MFC was very promising for practical application in bioenergy production and treatment of fruit wastes.

Renewable energy is expected to be a promising alternative to current energy sources. In our PV photovoltaic system, the photovoltaic panel is the master part. Its electrical model with corresponding equations are elaborated. We determined the intrinsic descriptive parameters of the PV panel, in order to carry out our simulation, in order to better understand and predict its behavior towards external factors. We superimposed the characteristics we obtained, after our characterization, with those provided by the manufacturer. The results coincide. The RMSE calculation yielded conclusive results. A microbial fuel cell is also adopted using leachate from sheep manure. This bio-fuel replaces the platinum-based mineral catalyst for the traditional fuel cell with a bacteria that forms a biological film on the electrode surface. In this paper, we describe the protocol for developing a graphite carbon based bio-anode. This bio-anode has been characterized with the two electrochemical techniques adopted which are chronoamperometry and cyclic voltammetry. Another party is interested in characterizing and modelling the electrical behavior of the battery. The results obtained are advanced. After an analysis of the energy context, a state of the art of electrochemical components coupling hydrogen and electricity is presented, particularly on electrolysers and regenerative or unitized reversible fuel cells. Finally, this model is used to study the modularity of components, including electrical and thermal imbalances in series or parallel associations of fuel cells or electrolysers. An architecture combining these elements with a photovoltaic generator to power an electric load or an electrical grid is finally submitted.

In addition to their utilization in membrane separation processes (electrodialysis, dialysis, electro-deionization, etc.), polymer ionic membranes are utilized as a separator in fuel cells (hydrogen, biological and direct methanol fuel cells, etc.) [1]. In the latter, the oxidation of methanol generates electrons that circulate in the external circuit to feed a load (electrical resistance) and the protons migrate through the membrane, and combined with oxygen at cathode to yield droplets of water [2]. In this work, the proton transfer through the membrane was studied with voltamperometry by plotting current-voltage curves. The effect of methanol during proton transfer has also been studied by giving the limiting currents. The transport of proton through the membrane, has been investigated in two media: aqueous solution and hydro-organic solution. Moreover, the stability of applied current through the Nafion membrane, was also studied by using the Hittorf cell for determining the transport numbers of metal ions.

Light induced degradation (LID) of carrier lifetime and electrical performances were investigated in this study on Boron-doped silicon wafer and solar cells. Boron-doped P-type Silicon Czochralski monocrystalline (Cz-Si) and multicrystalline (Mc-Si) wafers are used in this work. Measured Minority carrier lifetime before and after a prolonged illumination show a very fast degradation in the first few minutes and reach a complete degradation after four hours in Si-cm wafers and after 28 h in Cz-Si one. The normalized effective density of the metastable Boron-Oxygen (BO) defects was calculated by means of the difference between the inverse of the measured lifetime before and after illumination and it is proportional to the boron concentration. Analysis of the lifetime minority vs. injection level $$ \Delta {\text{n}} $$ using Shockley-Read-Hall theory shows that the prolonged illumination generate a deep BO defects Ec-Et = 0.45 eV with a ratio of the capture cross section $$ {\text{k}} =\upsigma_{\text{n}} /\upsigma_{\text{p}} = 15 $$. The obtained results show that the Cz-Si is more sensible to the electrical degradation properties under illumination than the Mc-Si wafers and cells despite the higher boron concentration. The second phenomena related to the BO metastable defects saturation density $$ {\text{N}}_{\text{tsat}}^{*} $$ is reached rapidly in the first 4 h compared by the 28 h in the Cz-Si samples. This can be explained by the predominance of the oxygen content in the creation of the $$ {\text{N}}_{\text{t}}^{*} $$ concentration than the boron and the high density of the vacancy sites in the Mc-Si which accelerate the oxygen dimers (O2i) diffusivity and their reaction with the substitutional boron atoms.

In the framework of the Density Functional Theory (DFT) we have exploited the (FP-APW + lo) method to explore the optical properties of HgSe wurtzite unit cell and Hg1−xSex (x = 0.37, 0.50) supercells considered in a hexagonal phase and under the stoichiometry constraint. Our results, exploiting the mBJ correction, show that the HgSe wurtzite unit cell and Hg0.50Se0.50 hexagonal supercell exhibit same reflectivity behavior, however the latter is slightly less opaque. Moreover, The Hg0.37Se0.63 supercell has, optically, a semiconductor character only for electromagnetic radiations with // incidence. Our results show also that beyond 16 eV, the refractive character is insensitive to the direction of incidence for both the HgSe wurtzite unit cell and Hg1−xSex (x = 0.37, 0.50) hexagonal supercells. Also, the energy loss by absorption, for our supercells, is more important for ⊥ incident radiations within energies lower than 5 eV. Our photonic study shows that the birefringent character is more pronounced for the Hg0.37Se0.63 supercell.

In this work, a simulation of the CZTSSe solar cell with Al/ZnO: Al/ZnO(i)/CdS/CZTSSe/Mo structure have been studied using the SCAPS-1D (Solar Cell Capacitance Simulator in one Dimension). The simulation results have been validated with real experimental results. Next, a novel structure is proposed in which a CZTSe layer is stacked in the back side of the solar cell in order to boost its performances. The efficiency of CZTSSe solar cell increases from 12.3% to 15.3% by inserting the CZTSe layer. Finally, we carried out an optimization of different physical parameters (Thickness and doping concentration) of CZTSe stacked layer to determine the optimum values. The proposed structure of CZTSSe solar cells with optimum parameters showed higher functional properties. The maximum value of efficiency achieved was 16.77% with JSC = 36.81mA/cm2, VOC = 0.657V and FF = 69.19% under AM1.5G illumination at 10 nm thickness and 5E19 cm−3 doping concentration.

The technology of photovoltaic energy conversion is essentially based on semiconductors that have different physical properties, which consequently result in photovoltaic panels of different yield and lifespan but also different costs. Among these semiconductors, those belonging to the chalcopyrite family have attracted the attention of researchers around the world given their very varied physical behaviours and their syntheses, which are not too complicated. In this work, we are interested in MgGeAs2-chalcopyrite. This compound has been studied in detail by several authors except that several physical properties remain unknown including some of its elastic properties and the effect of hydrostatic pressure on its mechanical stability and its narrow band-gap. The study has been carried out with FP-LAPW method as implemented in WIEN2k code. The found results for the structural properties are in good agreement with the previous results. Structural parameters allow the determination of the elastic constants under different pressures. The mechanical stability of this compound has been studied. The value of band-gap energy of this compound has been obtained by several methods including TB-mBJ and GLLB-SC. Optical properties are also the subject of our work, from which the dielectric function and the absorption coefficient of this compound have been analyzed.

Carbothermal reduction of light metals and semiconductor such as Al, Ti and Si under argon gas not only can reduce the reaction temperatures but can also minimize the formation of carbides and oxy-carbides intermediate compounds. The calculation of the gas phase diagram of Al-O-C, Ti-O-C and Si-O-C system suggests the possibility of the enhancement of the Al, Ti and Si product yield by the increase of the ratio of the partial pressure Al2O/CO, TiO/CO and SiO/CO. Thermodynamic considerations associated with this process are discussed along with the experimental results obtained over a wide range of parameters under argon gas using an induction heating furnace (IH) in a high temperature reactor. Powder mixtures were prepared of stoichiometric mixtures using powders either of alumina or silica or Titania with carbon. Experimental results obtained in induction furnace setup such as the pure element’s yields as a function of the CO partial pressure, PCO, temperatures range in the reaction zone of 1400–1800 °C and different deposition temperatures are presented. In this research work, we calculated the thermodynamic phase diagram with the partial pressure ratio of Al2O/CO, TiO/CO and SiO/CO. This diagrams suggests the possibility of enhancement of Al, Ti and Si yield by the increase of P(Al2O, TiO and SiO)/P(CO). At the optimal condition, the Al and Si yield was improved comparably to Ti which still under research.

The most well-known solar cells are made of semiconductors, mainly based on crystalline silicon (mono- or poly-crystalline). It consists in converting solar radiation into electricity. Generally, the solar cell device that can carry out this function is essentially a single PN junction with large surface. The most of solar cells on the market today are based on silicon crystal. Currently, multiple researches are in progress in order to realize cells with multi junctions, tandem, by connecting to the silicon cell, another cell based on a material with wide gap energy in order to obtain a better efficiency. In this paper, we studied the efficiency of a silicon solar cell by using TCAD—Silvaco tools. The silicon solar cell structure was defined using Athena 2D process simulator that permit to create the structure in order to study it and use it in predictive simulation. On the other hand, the electrical simulation was performed using Atlas simulator. After simulation, the final output parameters are Voc = 0.61 V, Jsc = 23.267 mA.cm−2, FF = 0.795 and 11.30% of efficiency.

In this paper, TiO2 thin films were first deposited by RF magnetron sputtering on glass substrates at different temperatures. Then, the obtained samples were characterized by several techniques: X-ray diffraction, scanning electron microscopy, atomic force microscopy and ultraviolet-visible spectroscopy. Hence, after a brief description of the preparation conditions we investigate the effects of substrate temperature, Ts, (RT, 200, 300 and 400 °C) on structural, morphological and optical properties of all prepared TiO2 thin films. It was found that increasing Ts leads to several interesting phenomena: (i) more uniform distribution of densely packed well-defined grains (ii) the root mean square roughness increases from 3.88 to 9.56 nm, (iii) improvement of the crystalline structure, (iv) the crystallite size increases from 13.4, to 22.3 nm, (v) the films are highly transparent in the visible region and (vi) the direct optical band gap value of the films is found to decrease from 3.64 to 3.46 eV. These dependences, in agreement with literature, are of great importance in TiO2 potential material applications in optoelectronic and photovoltaic fields.

The Ag/MgPc/GaAs/Au-Ge organic heterojunction diode is fabricated by low cost spin coating technique. Dielectric and impedance measurements within 500 kHz–1 MHz range of organic heterojunction diode are investigated at room temperature for renewable energy applications. A broaden peak and decay of capacitance to negative values are recorded for 500, 700 kHz and 1 MHz applied frequencies within −2, +5 V biasing voltage range. The negative capacitance (NC) of our organic device is observed inside the forward bias voltage range. Increase of conductance with decline in frequency within forward bias voltage is recorded inside the same voltage range. Ac conductivity is frequency dependent in particular within forward voltage range and exceeds 3.5 µS/m at lower frequency. Dielectric constant of organic diode follows similar variation as that of C-V for measured frequencies. Dimensionless parameter M″ versus M′ for applied frequencies is represented in Cole-Cole diagram. It is recorded a highest value of 0.6 for 1 MHz.

In this paper, a contribution to the classification of the various categories of amorphous hydrogenated silicon oxynitride films using infrared spectroscopy has been carried out. A wide variety of these films were prepared by plasma enhanced chemical vapor deposition technique. As the gas ratio of N2O/(N2O + NH3) flow rates increases from 0 to 0.97, four categories of amorphous films were identified by infrared spectroscopy namely: the hydrogenated silicon nitride, the nitrogen-rich silicon oxynitride, the oxygen-rich silicon oxynitride and the highly oxygen-rich silicon oxynitride films. Finally, the concentration of Si-O and Si-N bonds present in the hydrogenated silicon oxynitride films were successfully correlated with the gas ratio R = N2O/(N2O + NH3), in the context to optimize of their vibrational properties for different applications.

SnO2 nanoparticle thin films are obtained using simple spray pyrolysis chemical process with 0.1 molar concentrations on glass substrate at: T = 300, 325 and 350 °C respectively. The deposited films were investigated using the appropriate method of characterization. The X-ray diffraction revolved that the deposited SnO2 nanoparticle thin films have tetragonal rutile structure. The scanning microscopy (SEM) and Atomic force microscopy (AFM) indicate that films are homogenous and uniform in all direction with small grain size (10–14) nm. The UV-visible spectrophotometry showed that the transmittance of the films is above 85% in the visible and band gap Eg around 4 eV.

Light trapping plays an important role in improving the power conversion efficiency of thin-film hydrogenated amorphous silicon solar cells. Therefore, doped microcrystalline silicon oxide has received much attention due to its versatile applicability in photovoltaic technologies. It is a mixed phase material of an oxygen rich amorphous silicon oxide phase, which supplies low refractive index, a wide band gap and high optical transparency and the doped microcrystalline silicon phase, which guaranties agreeable electrical conductivity. In order to evaluate the microcrystalline silicon oxide based single junction p-i-n solar cell efficiency, a simulation study is executed using AMPS-1D (Analysis of Microelectronic and Photonic Structures) simulator.The simulation results show that hydrogenated microcrystalline silicon oxide n-layer has a significant effect on the cell performance and that amorphous silicon a-Si:H solar cells using hydrogenated microocrystalline silicon oxide instead of the conventional hydrogenated amorphous silicon n-layer show good electrical performance, which is apparent as an increase of efficiency from 6.513% to 8.736%.

The ab intio method within the recently modified Becke-Johnson potential explore that the Ag2BaSn(Se, S)4 compounds are narrow band gap semiconductors. The lattice parameters, bulk modulus and its derivative are predicted. The calculated elastic constants satisfy Pugh’s criteria. The mBJ potential was selected for further explanation of optical properties of these compounds. The two non-zero dielectric tensor components show isotropy behavior between the perpendicular and parallel components. Based on the results our finding that the Ag2BaSn(Se, S)4 compounds are efficient materials for energy conversion.

We investigate the dielectric properties of random resistor-capacitor networks (RRCN) modelling barium titanate (BaTiO3) ceramics doped with different rare earth additives. The host matrix of BaTiO3 is regarded as a dielectric RRCN, where the effect of conductive inclusions is modelled by a random incorporation of resistors having small resistance. In order to model the effects of blending silver, nickel, etc., into barium titanate on the effective dielectric properties of the composite, Frank and Lobb algorithm is used to calculate the effective conductivity, resistivity and permittivity of the network at different proportions of conductive inclusions. This network approach indicates similar properties trends to that observed experimentally, a qualitative agreement with the Maxwell equation is obtained at low proportions of conductive inclusions.

Organic cells based on conjugated polymers such as P3HT have attracted many research interests because of their advantages and potential for continuous development. A computational study on the performances in bulk heterojunction (BHJ) organic solar cells of P3HT: graphene was done. We have used the Solar Cell Capacitance Simulator (SCAPS) intended for solar cells; we have choose the effective medium model (EMM) to simulate the active layer lightly doped P. It is assumed that the two materials are very well interpenetrated in the active layer with a distance between all points of the blend and a donor/acceptor interface being as inferior to the diffusion length of the excitons. The appropriate parameters were introduced in platform of (SCAPS) simulator. (J-V) chahracteristics, the quantum efficiency and performance parameters (Voc, Jsc, FF and η) were simulated. The organic solar cell performance parameters (Voc, Jsc, FF and η) are affected by the weight and electron affinity of Graphene in the blend P3HT:graphene.

A theoretical study of structural and electronic properties of chalcopyrite semiconducting materials is presented using the full-potential linearized augmented plane wave method implemented in Wien2k computational package. In this approach, the Generalized Gradient approximation was used for exchange correlation potentials. Our interest in these semiconductor materials is motivated by their promising roles in the manufacture of thin-film solar cells because of their interesting structural and electronic properties.Results are given for lattice constant, bulk modulus and its pressure derivative for chalcopyrite materials specifically based on copper indium sulfur (CIS), copper gallium sulfur (CGS) and copper aluminum sulphur (CAS). Band structure are also given. The results are compared with previous calculations and with experimental measurements.

The main purpose of this work is to analyze the comparison between the current voltage characteristic modeling of a mono-crystalline photovoltaic panel using classical and Design of Experiments methods. These methods based on mathematical models have been solved using numerical method, therefore, the main difference between them is in the process of the response output calculation that the classical one need several input parameters, which is obtain analytically. By cons, the design of experiments method is a fast tool to calculate the response, it consider only input and output parameters, discuss the obtained models and the associated calculation methods that we have evaluated via Matlab and Minitab development soft wares. In this contribution, we present the important steps to model the studied system, and we consider experiments concept allows finding the best possible model that both represents the experimental data and enables accurate predictions of the responses according to input variation factors in a strict definite study domain.

Zinc oxide is known for various applications because of its physicochemical, optoelectronic and piezoelectric properties which are strongly related to the size and morphology of the material. In the present work, we deposited ZnO nanofilm by sol-gel spin coating on glass substrates. X-ray grazing incidence analysis shows a wurtzite structure. The thickness measured by profilometry is about 200 nm and a strong photoluminescence in the visible range has been observed. The atomic force microscopic observation shows a regular arrangement of ZnO grains in the form of hexagonal nut, this morphology improves the roughness of the layer which increases its diffusion of light which is highly desirable for use in the field of solar cells.

In this paper we presented a numerical simulations using SCAPS-1D device model of chalcopyrite (CIG(S,Se)) solar cells. In order to increase the efficiencies of CIGS device, we simulated an alternative ZnO/CdS/CIGS/AlGaAs and ZnO/CdS/CIGS/InGaAs structure. There is an interesting enhancement of the efficiency of CIGS/AlGaAs or /InGaAs and compared to the conventional CIGS solar cells. Our simulation results show the possibility for the present solar cells give conversion efficiency of 28% for CIGS/AlGaAs and 26% for CIGS/InGaAs respectively. The present results showed that the addition of AlGaAs or InGaAs layer thin film CIGS solar cells structure has performance parameters according of Band Gap of CIGS.

The search for low-cost materials ton turn solar energy into electricity is a challenge for researchers. Lead-free perovskite solar cells have been of interest for research because of the toxicity of this material. The perovskite CH3NH3PbI3 solar cells have a conversion efficiency of about 22%. In this work lead is replaced by germanium. The solar cell analysis is performed using a digital tool «Solar Cell Capacitance Simulator (SCAPS)» Solar cell capacitance simulator was developed by Marc Burgelman at the University of Gent. SCAPS is used to analyses the micro and poly crystalline and photonic structure. SCAPS measure various parameters of a solar cell like open circuit voltage, Fill Factor, Short circuit current density, PCE. SCAPS and runs using the governing equations which includes continuity equations, Poisson equation, of electron and hole. The solar cell structures is based on the mixed perovskite compound as an absorbent layer and Pedot:Pss is used as HTM; PCBM is used as ETM. The contact materials are FTO coated glass (Front contact) and Al (back contact) is used. The total cell structure Al/Pedot:Pss/CH3NH3GeI3-PCBM/FTO. We study the influence of thickness of absorber layer on solar cell performance, efficiency (η) open circuit voltage (VOC) and short-circuit density (Jsc) and fil factor (FF).

The use of calcium hydroxide as sorbent of CO2 in low concentration streams (1% CO2 vol.) has been experimentally investigated. For that purpose, a CO2/N2 dry gas mixture, at ambient temperature and atmospheric pressure, was flowed through a bed of Ca(OH)2, and the concentration of CO2 in the effluent gas was monitored. In order to improve the fluidizability, both hydrophilic and hydrophobic nanosilica particles were added to the sorbent, and its effect on the absorption of CO2 was investigated. The results showed that the addition of nanosilica increases the capture capacity of the sorbent (compared to the raw material), and the best results were obtained when using hydrophilic nanosilica. Additionally, to elucidate how the CO2 capture process is affected by relative humidity during the storage of Ca(OH)2, the sorbent was kept in a controlled CO2-free atmosphere with constant humidity prior to the experiments. The results showed that samples stored in an atmosphere with high relative humidity exhibit a significantly higher CO2 absorption capacity.

Metal particles arranged in a powder bed or injected through a nozzle can be used in manufacturing 3D parts by selective laser irradiation or directly deposited on a base material. To obtain complex manufactured parts suitable for a use in specific application in order to improve product performance for industry, medicine, or any other advanced technology, there is still issues to be addressed in relation with the fundamental mechanisms occurring during laser-matter interaction. This can be established through investigations including mainly modeling and simulation approaches. Some results of modeling and experimental approaches are presented for the LMD (Laser Metal Deposition) and the SLM (Selective Laser Melting) processes. The experimental part uses powder jet, it was performed in collaboration with the CSIR-National Laser Center of South Africa in the framework of the ALC projects program, whereas preliminary results for powder bed use in laser additive manufacturing are given for the selective laser sintering/melting technique (SLS/SLM).

Carbon dioxide dissociation using dielectric barrier discharge has been experimentally investigated. The electrical discharge was stimulated using high voltage pulses of nanosecond duration, with a repetition rate in the range of 100–1000 Hz. The reactor consisted of two stainless steel plane circular electrodes covered with either fused silica glasses or polytetrafluoroethylene (PTFE) films. Experiments were carried in pure CO2, and the concentration of carbon monoxide and ozone in the effluent gas was determined using UV/VIS and FTIR spectrophotometry. The results have shown that using silica as dielectric layers results in a higher generation efficiency for both CO and O3.

The quality control of the solar cells in the industrial chain is necessary to detect the responsible defects on the efficiency of the solar panels. In this context, we analyzed a polycrystalline silicon solar cell by Laser Induced Breakdown Spectroscopy (LIBS). The target was irradiated by a Nd: YAG pulsed laser at the fundamental wavelength λ = 1064 nm with an energy of 20 mJ. Based on the color of the used solar cell, two zones were detected: a blue zone representing the silicon wafer and a white zone representing the contact metal ribbons. Seven elements were detected in the white zone and only four in the blue zone. The distribution of the different elements in the sample is like a depth function called “Depth profiling” which can give us useful information about the constituent layers of this sample. In this work, the depth profiling of the various detected elements versus the number of laser shots was examined to understand the distribution of the elements in the volume of the solar cell.

The Single and double frequency non-equilibrium capacitively coupled (CCP) radiofrequency plasma sources are commonly used in the laboratory for research and for a variety of processing and techniques. This study is carried out on the basis of a one-dimensional, self-consistent fluid model and corresponding governing equation are described in details in the present report. Our simulation results show that the ozone ($${\text{O}}_{3}$$) is efficiently generated in the bulk of the discharge in case of helium-oxygen admixture as compared to our recent work [1] carried out on pure oxygen. They also show that the formation of the metastable singlet molecule ($${\text{O}}_{2} \left( {{\text{a}}^{1} \Delta_{\text{g}} } \right)$$) and the atomic oxygen ($${\text{O}}$$) are important as compared with pure oxygen plasma and which has a significant influence on the electron heating process. This is due to high rate of production of these species and low rate of destruction and recombination. The rate of production of negative oxygen ($${\text{O}}^{ - }$$) and positive ($${\text{O}}_{2}^{ + }$$) molecular ions are also important but less than the neutral atoms and molecules. The formation of positive ($${\text{He}}^{ + }$$), ($${\text{He}}_{2}^{ + }$$) and ($${\text{O}}^{ + }$$) ions are almost of the same order of magnitude which is about 10−2 less than the ($${\text{O}}^{ - }$$) and ($${\text{O}}_{2}^{ + }$$) ions. This can be explained by the fact that the electron-impact ionization of oxygen molecules can dominate over helium ionization due to the lower ionization threshold of the oxygen molecule (12.6 eV for $${\text{O}}_{2}$$ vs. 24.6 eV for He).

The aim of the present work is to investigate the effect of gas heating distribution in the gap of dielectric barrier discharge DBD reactor in pure oxygen gas for ozone production. The fluid model combines the means physical processes in the DBD discharge for ozone generation, and the heat transport equation resolution were used for determining the gas temperature profile. The numerical findings of the model are able to predict the evolution of gas temperature in O2 DBD reactor. In order to clarify the influence of the operating conditions of the discharge on the gas temperature, we study this instability phenomenon by varying of the applied voltage, the pressure, the frequency, and the pressure to optimize ozone generation. The results obtained from this study show clearly the rise in gas temperature is mainly depends to the high values of deposited power in DBD reactor. The increase of gas heating in the discharge can affects significantly the efficiency of ozone production.

In this work, we determine precisely the electric wind velocity, produced by a direct current (DC) corona discharge in air, using three electrode geometrical configurations: ‘wire-to-plate’ (a), ‘two wires-to-plate’ (b) and ‘three wires-to-plate’ (c). Each electrode wire is subjected to the same high positive voltage while the plate is grounded. The electric wind velocity is determined through a mathematical model based on the resolution of Navier-Stokes equation, in which a source term consisting in the electro-hydrodynamic (EHD) force, already established by our group in the form of a simplified analytical expression, is used. The results found allow to compare the profile of the electric wind produced by the corona discharge for the three electrode geometrical configurations ((a), (b) and (c)).

The Electrical breakdown in a gas is the process of transition from the quasi-insulating state to a conducting state when a sufficiently intense electric field is applied. The value of the voltage associated with this transition is called breakdown voltage it corresponds to the first value of the voltage for which the discharge becomes autonomous or self-sustaining. The understanding of the breakdown process is necessary for the development of plasma applications. Our work consists in determining the breakdown voltage as a function of the interelectrode distance pressure product which represents the Paschen curve in a plane geometry by an analytical resolution of the self-sustaining condition coupled to the equation of the Townsend first coefficient and the electric field. The results obtained from this resolution allowed us to describe and verify and of course to test the validity of our results with experimental measurements studied by several authors. This work was the object of analysis of the effect of certain parameters which are qualitatively in agreement with that of the experience.

Laser pulse induced photo-detachment is an indirect measurement technique devoted for the estimation of plasma electronegativity, i.e. ratio of negative ion density in proportion to electron density. The technique combines the use of a laser pulse and a positively biased Langmuir probe. The laser pulse converts negative ion into electron-atom pair, while the Langmuir probe records the increase of electron saturation current due to the electron density increase induced by negative ion photo-detachment. The negative ion proportion is thereafter deduced from the recorded laser photo-detachment signal which is nothing but the temporal evolution of probe current measured from the instant when the laser pulse is fired until the probe current recovers to its nominal value (prior the laser pulse). As in any indirect measurement technique, one needs a model describing the relationship between observables (electron saturation current) and investigated quantities (electronegative plasma properties). Such model relies on a set of assumptions that are subject of discussion in the present review.

This paper presents the experiments achieved in the DPHE laboratory in collaboration with the LPPMCA laboratory for the development of mercury-free fluorescent lamp concurrent light. Mercury emits UVs photons at a wavelength of 254 nm, but due to its high toxicity, mercury (Hg) has been classified by the World Health Organization (WHO) as one of the top ten chemicals posing a major risk to public health [1]. It is thus necessary to develop new free mercury UV light sources for decontamination of wastewater and water sterilization processing. Dielectric barrier discharge (DBD) interest to “lighting designers” who, for environmental considerations (energy saving and mercury disposal), would like to replace the mercury of discharge lamps [2, 3]. The excitation of rare gases by DBD provides a beneficial arrangement for the generation of radiation in the VUV, UV and IR range. The scope of this study concerns the domain of low-pressure, low-power fluorescent lamps. We focused on the electrical characteristic, optical emission spectroscopy of plasma produced in a dielectric barrier discharge by a high pulse generator (3 kV–100 kHz). The first purpose of these measurements is to analyze the operating range of the plasma lamp and optimize it in order to improve efficiencies.

A plasma producing between tow electrodes one of them or the tow of them covered by a solid dielectric or placed between them, called a Silent discharge or dielectric barrier discharge DBD. The presence of this dielectric it’s to avoid the transition to arc. This process have a several applications, such as ozone generation, surface treatment, light source and other environmental industries. That for cold plasma characteristics, and the simple operation with atmospheric pressure. However, this paper propose contribution of modeling and simulation of dielectric barrier discharge in pure oxygen at atmospheric pressure using COMSOL Multiphysics to explain and understand physical behavior of various species created in plasma from O2, by setting the mathematical and chemical model, courant and voltage characteristics during the break down was presented in results. In addition, the number density variations of species (charged species and neutral) across the gas in special scale is shown.

In this paper, the characteristics of a xenon lamp are studied. In this lamp, the discharge is produced between two electrodes covered by dielectrics to protect them from the gas effects, to limit the current and to reduce the applied voltage. A one dimensional particle in cell model with Monte Carlo Collisions (PIC’MCC) was then used. The computer model allows to investigate two equivalent dielectric capacitances; 0.82 pF/cm2, 230 pF/cm2. The results show temporal variation of the different voltages in the simulation domain and the current density, spatiotemporal variation of electron density and electric field is also discussed. The discharge pulse is more important for 230 pF/cm2 with less applied voltage (2.7 kV). The effect of dielectric capacitance is clearly seen on energy deposition into the different collisions. For higher capacitance, electrons use more energy to excite xenon atoms. This energy is used effectively into xenon metastable, which can contribute to an efficient discharge VUV emission. The energy deposited into high levels is not significantly affected.

Recently considerable attention focused on the development of excimers and exciplexe lamp. These lamps are sources of spontaneous radiation based on the transitions of excited molecules called excimers when pure noble gas or a mixture of several noble gases is added. The excited molecules are considered to be exciplex when the gas mixture contains one or more halogens in addition to noble gases or mercury. The de-excitation of these molecules to their dissociative fundamental states induces a loss of energy in the form of UV, visible and IR radiation. The work is based on an experimental study of a pure krypton lamp and theoretical study of the Kr/Cl2 plasma chemistry in terms of the homogenous model. The lamp is excited by a dielectric barrier discharge, the gas breakdown is obtained between two flat and identical electrodes of 5 cm × 5 cm surface area, these electrodes are insulated and separated by two dielectric plates of permittivity 4 and thickness 2 mm. The space between the two dielectrics is 2 mm and is filled with gas at pressure of 129 to 460 mbar. In order to carry out a parametric study, the influence of several parameters such as applied voltage, frequency and gas pressure was studied. A spectroscopic and kinetic analysis of a pure krypton and Kr/Cl2 mixture excilamp excited by DBD is reported here. The interpretation of the experimental and theoretical results allowed to explain chemical processes responsible of the production of excimers inducing UV emission and to link these processes to the IR emissions that control the population of the excited metastable states of krypton. These states are indirectly responsible for UV emission.

In this work, nitriding by Plasma Immersion Ion Implantation (PIII) treatment of low carbon steel was performed in a plasma reactor with an inductive RF source (l3.56 MHz) at low pressure in order to investigate the influence of the process conditions on the hardness and corrosion properties. A space charge sheath region is formed in front of the sample biased with a negative DC voltage. The positive ions accelerated within this sheath reach the sample with a high kinetic energy. The micro-hardness increased by ~100% for the nitrogen-implanted samples compared to the untreated one, the nitride phases (γ’-Fe4N and ε-Fe2-3N) are believed to participate to the hardening. A low corrosion rate is obtained, which indicates that nitriding by PIII improves the corrosion resistance behavior. These results are particularly interesting since they have been obtained for short treatment time (2 h) and relatively low bias voltages.

The objective of this work is to study the effect of changing the electrode configuration (‘wire-plane’ (a), ‘two wires-plane’ (b) and ‘three wires-plane’ (c)) on the spatial distribution of the neutral chemical species generated by a positive corona discharge, with a special focus on the effect of the electric wind on the distribution of these chemical species. This task is accomplished using a mathematical model that is based on the numerical resolution of Navier-Stokes equation coupled to the continuity equations of neutral species generated by the positive corona discharge. Regarding the chemical reactions, a model of plasma chemistry, which includes the most important chemical reactions occurring between electrons, atoms and molecules in the air, has been used. One of the main results is the comparison of the ozone density produced by the positive corona discharge for the three mentioned electrode configurations.

The effect of the discharge parameters on gas temperature in Ne–Xe dielectric barrier discharge DBD is investigated for operating conditions typical to excimer lamps functioning at high pressure. The gas heating effect in the DBD of gas mixture can affects the electrical characteristics of the excilamps, and consequently the homogeneity of excimer density. The gas temperature effect is originating from Joule heating approximation. The gas temperature development in the discharge was calculated by the heat transport equation resolution. This equation was coupled with the transport equation of the electrons and the ions of fluid model for a parallel-plate dielectric barrier discharge DBD. A parametric study of the influence of some discharge parameters such as the applied voltage, the total gas pressure, the dielectric capacitance, the xenon content in mixtures, and the secondary emission coefficient at the dielectric material is essential to see the effect of these discharge parameters on the rise of gas heating and consequently to the excilamps efficiency.

In this investigation, a numerical simulation has been performed based on the SMARTS2 model to study the influence of the zenith angle on the variation of the total atmospheric transmittances. This calculation has been made for ultraviolet and visible light in the range of [0.2, 0.39 µm] and [0.4, 0.75 µm], respectively by taking into account the absorption and the scattering of radiation by the atmospheric gas molecules as well as aerosols. In order to determine the direct dependence of the total atmospheric transmittance on the light wavelength, a regression approach has been used for four values of zenith angles [0°, 25°, 35°, 57°]. The result shows that total atmospheric transmittance can be modeled by a polynomial function of sixth order which describes fairly the atmospheric transmittance as a function of wave length and zenith angle. More importantly, the comparison between our present results and Modtran’s results shows a good agreement with relative reduction ratio of transmission equals approximately to 1.

This work is devoted to studying the effects of temperature exposure on PC properties as a function of time. The samples underwent isothermal treatments at 80 °C, under air, in a thermo-regulated oven. Spectroscopic and physical-chemical analysis techniques highlight the structural modifications of the material. As a result, the maintenance generates physical and chemical aging phenomena and a crosslinking process which are causing a change in the characteristics of the aged material.

A statistical analysis of simulated road traffic in the city of Oran is used in order to propose solutions for pollution reduction. There is a large number of vehicles circulating in Oran, leading often to traffic jams. These jams are an important source of air pollution because of the high fuel consumption. A characterization of the different phases of road traffic is required to predict and prevent the congestion phase. The SUMO code is used in this work to simulate the movement of cars on the most important roads and crossroads in Oran. A flow and velocity analysis clearly shows the existence of a critical vehicle density at which congestion phase transition appears. From the results analysis, it is concluded that at high speeds a car is polluting fast compared to average speeds. It has been noticed that the closer we get to traffic jams, higher is the pollution.In a next step the effect of road signs and traffic lights would be examined to optimize the signaling as to reduce traffic jams and of course emissions of organic volatiles.

Electrocaloric cooling is an ecological refrigeration technology based on the electrocaloric effect. We don’t use HCFCs, HFCs, CFCs, and NH3, as a refrigerant. This paper reports an electrocaloric refrigeration with Al2O3/water as heat transfer nanofluid to vehiculate the fluxes between the CHEX and HHEX; the cold and hot heat exchanger; respectively, and BaTiO3 as electrocaloric material near room temperature. The electrocaloric effect ECE is the adiabatic temperature change (ΔT) of a ferroelectric material during the application or removal of applied electric fields; during the polarization and depolarization processes, The mathematical model (Thermal, Electricity, and CFD) for electrocaloric refrigeration systems is composed with comsol, to optimize the electrocaloric effect ECE in electrocaloric refrigeration system. The results obtained are; the temperature span ΔT; cooling power for different frequency of cycles and coefficient of performance.

This paper presents a performance evaluation of a grid connected photovoltaic system of 10.5 kWp installed on the roof of a building at the Renewable Energy Research Unit in the Saharan environment (URER/MS) in Adrar (Algeria) in the desert conditions. The monitoring data of the PV system over a 3 months period (26 March 2018 to 26 June 2018), are used to evaluate weekly and monthly energy yield, losses, conversion efficiency, performance ratio and capacity factor, which are the most and appropriate parameters widespread in the literature. This assessment results have been analyzed in detail in order to support the Algeria’s national renewable energy program, particularly the choice of PV plants injected into the grid in the middle of the Sahara. This study shows that the maximum Array capture losses and thermal capture losses with a weekly average 2.39 h/day and 0.51 h/day respectively. The weekly average values of the performance ratio, capacity factor, efficiency of the PV module and system were 63.67%, 33.56%, 10.07% and 9.74%, respectively. The energy generated by PV system is 3.41 MWh and 96.63% of this energy is injected into the grid.

Solar drying has been identified as a promising alternative to sun drying for drying of fruit and vegetables in developing countries because of its minimal operational cost in terms of fuel. It is also a convenient alternative for the rural sector and other areas with scarce or irregular electricity supply. Studies conducted on solar drying have proved that it is a good alternative to sun drying for the production of high-quality dried products. This paper is focused on the thermal and the economical study of a direct solar dryer. The thermal study was performed using numerical simulation while the economic evaluation was done by computing life cycle cost (LCC) and life cycle benefit (LCB) of the solar dryer. Different techniques of heat supply such as: heat exchanger, porous medium and phase change material (PCM) were tested and studied throughout this paper. The performed economic analysis proves the feasibility of our solar dryer; however, the heat supply technique of heat exchanger with geothermal water was chosen as the most recommended one forasmuch to the short payback period (0.9 year) obtained when using this technique.

South Algeria has a vast area with an arid climate. The summer season is characterized by the high-level use of conventional air in the residential sector. The stage of consumption in this sector is one of the major concerns expressed in the framework of the Algerian energy consumption model. The bioclimatic house standard is rapidly spreading across the world, it becomes necessary for Algeria to exploit this standard for facing the important increase in electricity consumption. In Algeria, fossil fuels are the largest source of electricity production. The environmental problems caused by the use of fossil fuels are well known: air pollution, greenhouse gases, and aerosol production. Ksar’s architecture has been recognized as an example of adaptation in the desert climate in Algeria. This work presents useful ancient energy technology that has been used many years for the natural cooling of ancient buildings during the summer season in the South of Algeria. The investigation finds that two vernacular bioclimatic strategies can be translated to the present constructions: massive side walls and natural ventilation.

Once installed, photovoltaic panels tend to be forgotten, and covered with a thin layer of dust due to bad weather and pollution. To this can be added bird droppings, pollen, dead leaves or dead insects. All of these elements can have a long-term impact on the performance of the panels because they are likely to compromise the uptake of the sun’s rays. Our work is essentially based on the removal of impurities deposited on the solar panels by introducing mobile wave conveyors where travelling-wave dielectrophoretic forces move the materials. In this paper, we studied the displacement of millimetric and nanometric size particles using three-phase and two-phase conveyors that are connected to the virtual instrument to follow the speed of displacement and we obtained good results or all the particles were moving off conveyors. The use of the two conveyors showed that the two-phase conveyor is more advantageous than the three-phase economy side in equipment. Both factors (voltage and frequency) are important for mobile wave creation, hence the ease of movement of particles. The advantage of this technology lies in the fact that the transport of the particles is ensured by the forces of the electric field.

Atmospheric aerosols stand for a complex mixture of microscopic solid or liquid droplets particles suspended in atmosphere, consisting of both natural and anthropogenic origin. The aim of this work is to study the atmospheric aerosols coagulation process greatly enhanced by the Van der Waals forces and monitored by the Brownian motion. We focus on the evolution of the mass concentration of particles, which is consistent with existing regulations, and we focus on the density change of the particles during the particle growth processes. We analyse an approach for solving Smoluchowski’s coagulation equation employing the Monte Carlo probabilistic method based on the use of random numbers in repeated experiments. Additionally, several numerical simulations have been implemented and evaluated regarding their CPU times and their accuracy in terms of mass concentrations. The time step influence on the zeroth moment error is verified, as well as on the total number of simulated particles.

Magnetic cooling based on magnetocaloric effect is one of the most important candidate applications as solutions for enjoying a non-polluting environment. In this work, a study of the magnetocaloric effect (EMC) in La0.67Sr0.16Ca0.17MnO3 perovskite was made from an experimental measurement of magnetization as a function of temperature under low magnetic field and using phenomenological model. The results show 0.21 J/Kg K is the value of maximum magnetic entropy (ΔSmax) in this material perovskite near room temperature (Tc = 336 K). Furthermore it, from this phenomenological model, we were also able to calculate other properties. the values of the full-width at half-maximum (δTFWHM), the maximum and the minimum specific heat were found to be, respectively, 10.19 K, 9.41 and −9.19 (J/(Kg K)) under 0.05 T field change. In addition, a relative cooling power (RCP) of about 2.12 J/Kg. Compared to other materials, La0.67Sr0.16Ca0.17MnO3 appears to be a promising candidate for magnetic cooling near room temperature.

The protection of the environment through the reduction of solid waste and the reduction of greenhouse gases especially those emissions during the heating of buildings are objectives that can be achieved through the production of glass foam. In this study, we opted to prepare foam glass-gypsum composites destined to the coating ceilings and interior walls of buildings in order to expand employment of foam glass and to improve its performance including mechanical strength and facilitate their implementation. The foam glass is prepared by sintering at 800 °C with waste glass and calcium carbonate CaCO3 in the form of a panel of 150 × 150 × 30 mm, the plaster-foam glass composites are prepared in the form of sandwiches panels or complexes. Physicochemical analysis techniques as SEM-EDS, porosity, density, thermal insulation and mechanical strength tests have been used for the characterization of these composites. The results obtained from thermal insulation and mechanical tests clearly show that the sandwich panel shows the best results with a thermal conductivity of 0.027 W/m°C and a compressive strength of 1.423 MPa.

Air pollution, which continues to increase, gives rise to considerable concern. It is generated by energy production, industrial activities, agriculture and transport. The main gases responsible for this pollution are sulfur dioxide (SO2), nitrogen oxides (NOx) and carbon dioxide (CO2). Nowadays, carbon dioxide is one of the main gases to detect. In the present work, vanadium oxide thin film has been deposited on quartz crystal microbalance (QCM) using vacuum thermal evaporating method followed by thermal treatment, for CO2 gas sensor. The QCM covered with vanadium oxide film was heated at 200 °C for different times. The annealing time effect on the morphology and surface wettability of these structures has been investigated by using atomic force microscopy (AFM) and contact angle measurements (CA). The results show that elaborated surface exhibited roughness surface and Hydrophilic character. In addition, the exposing of this structure to CO2 gas shows that the fabricated structure can be used as a CO2 sensor at room temperature.

Photovoltaic power systems are known to be a clean energy source, their implementation into the electricity grid is the current trend in technologies and research. In this work dynamic economic dispatch issue incorporating an optimal sizing of a photovoltaic power system with battery storage system is solved by using Moth-flame optimization algorithm (MFO). Several simulations cases are processed while, the MFO algorithm is performed firstly over three units then six units test system. The obtained results are compared to other published works available in the literature to confirm the validity of the proposed method. In this paper, an optimal PV-ESS system have been sized through the proposed CDEED strategy. The reduction of emission gas and operating cost have been assumed in both of IEEE 3 unit and IEEE 6 unit systems. The Moth Flames Optimization (MFO) algorithm was employed as an optimization tool to minimize the objective function previously presented. The obtained results from the performed simulation of the 3 unit and 6 unit test system show the effectiveness of the proposed approach. As a further work, this issue will be extended by including the formulation of the Levelized Cost of Electricity (LCOE) considering the degradation rate and maintenance cost of PV panel, the battery lifetime and the cycles per day of charge discharge of the ESS.

Carbon dioxide capture is a global concern because of its effect on climate change, especially as regards to global warming. Absorption using physical and chemical solvents is the commonly used method to capture CO2. Ionic liquids (ILs) as advanced solvents have been regarded as appropriate candidates for CO2 capture because of their advantages such as non-volatility potentially that makes ILs “green” solvents, negligible vapor pressure and high CO2 solubility.This work aimed to study the feasibility of CO2 separation from a gas containing methane using the low viscosity ionic liquid 1-hexyl-3-methylimidazolium tetracyanoborate [hmim][TCB] as an alternative to conventional ones by simulation using Aspen plus V.8.0. Thermophysical properties were calculated using empirical correlations, and the experimental data for CO2/CH4 in presence of [hmim][TCB] were fitted with the NRTL activity coefficient model to determine the binary interaction parameters. The results show that lower solvent flow rate and lower energy consumption are required for the absorption with [hmim][TCB] than with organic solvents, especially for gas streams with moderate acid gas content.

The aim of our work is to conduct a study on the use of thermal insulation in the building sector. A solar prototype of the solar village built in Boussaâda is chosen to carry out simulation calculations using the Trnsys 17 software, in three different climates of Algeria (Algiers, Constantine and Ouargla). The solar prototype studied is equipped with devices allowing the use of passive solar energy with improved insulation. The simulation results of the passive systems show that the use of thermal insulation allows significant energy savings estimated at 34.48, 30.44 and 21.49% respectively for the cities of Algiers, Constantine and Ouargla.The passive system simulation results show that the use of these devices, such as Trombe walls and glazed surfaces, allows significant energy savings (although considered insufficient). A reduction in heating needs of 2.12, 1.7 and 2.64 times respectively for the cities of Algiers, Constantine and Ouargla is obtained.

Geothermal is a word that refers to both the science that studies the internal thermal phenomena of the terrestrial globe, and the technology that aims to exploit it. To capture the geothermal energy and apply it directly to the buildings is made use of a network of tubes in which circulates a heat transfer fluid which allows by coupling it to a heat pump, the heat exchange with the ground. This technology is still not widespread in Algeria; hence, the objective of this study is to allow its development by providing a methodology. In order to validate this methodology, a calculation of an installation of vertical probes was conducted to meet the hot and cold needs of a family home. For its design, we will take into account the contribution of solar energy passive and the use of thermal insulation along the envelope to reduce the energy requirements to allow the geothermal installation; it will then be dimensioned for the supply of heating, cooling and hot water. This design includes geothermal drilling, heat pump equipment and radiant floor installation.

A large quantity of air pollution is caused by the combustion of fuel. The Green Capacited Vehicle Routing Problem (GCVRP) is an extension of Vehicle Touring (VRP) that aims to minimize fuel or CO2 emissions or fuel consumption instead of total distance or with it in case of bi-objective optimization. The objective of the present work is to resolve the GCVRP with heterogeneous vehicles through a rule-based approach combined to an oriented object design. This technique using an existing environment that is Optaplanner. The modularity of the environment separates design and heuristics such as tabu search in java, rules and objective function in drools language, heuristics’ setting in xml from data and results in excel files. Moreover, it appears very useful to the resolution of the Green Capacited Vehicles Routing Problem. In this paper, the resolution was investigated on a customized Belgic dataset taken from an existing benchmark. The instance contains 50 cities. The final project will allow the reusability and the flexibility to add easily soft and hard constraints depending on the case study.

The elevating problems of climate change throughout the world along with the indiscriminate consumption of natural resources are creating a sense of urgency and environmental awareness, which call for fundamental changes in many industries, and the building sector is no exception. In this questioning of our model of economic growth driven by consumption and based on a greedy fossil fuel industry. Buildings consume the larger part of worldwide energy and are therefore major contributors to global greenhouse gas emissions. As a result, the construction sector has been identified as the sector with the largest potential to reduce energy demand and decrease GHG emissions. Over the past years, the need to fight the impacts of climate change imposes on designers and architects to improve existing techniques and adopt new strategies, technologies and methods that enable to fulfill the current challenges in terms of environmental, societal and economic considerations. Thus, the motivation arose to investigate new design ideas for buildings that could help solve such problems. We suggest in this research to question biomimicry, a new field that studies and emulates the forms, functions, and process found in nature, to solve human challenges. In this regard, the main challenge is how architects could use biomimicry as a tool for energy efficiencies design to attain buildings that respond adaptively to climate change and the environment? To sum up, our research aim is to demonstrate how to use biomimicry as an approach to enhance sustainable solutions for energy-efficient building design.