The Lithium (Li) Doping Effect for Enhancing Thermoelectric and Optoelectronic Performances of Co2NbAl

Cobalt -rich Heusler compounds represent a very interesting family among Heusler alloys due to their performance in the field of spintronics and magnetic devices. The quaternary Heusler created by swapping of an anti-atom site by an alkali element improves the performance of physical properties for new applications. In this study, the electronic structures and magnetic properties before and after swapping cobalt (Co) by lithium (Li) in the Co2NbAl compound have been investigated using first-principle computational calculations. Our findings revealed that the swapping Co antisite by Li keeps the half-metallic character in the CoLiNbAl. Analysis of band structures show that ternary Heusler compound is ferromagnetic half-metallic with half metallic gap (band gap in minority channel ) equal 0.134 eV but the swapping Co with Li leads the material to change its behavior and becomes a semiconductor with a gap equal 1.043 eV using HSE06 approach. The results of optical and thermoelectric properties such as absorption coefficient, reflectivity or thermopower and figure of merit are very interesting in the optoelectronic field and encourages the researchers to realize photovoltaic cell and thermoelectric generator with a higher efficiency. These interesting features suggest that Co2NbAl and LiNbAlCo Heusler compounds could be good candidates for applications of antiferromagnetic spintronics and optoelectronics in commercial semiconductor industry.

Numerical Investigation for Performance Enhancement of Photovoltaic Cell by Nanofluid Cooling

The cooling fluid is a key factor in cooling photovoltaic (PV) panels especially in the case of concentrated irradiance. Maintaining the panel at low temperature increases its efficiency. This paper investigates the usage of water-Al2O3 as a nanofluid for achieving the required cooling process. The particle concentrations and sizes are investigated to record their effect on heat transfer and pressure drop in the developing and developed regions. The research was performed using ANSYS CFD software with two different approaches: the single phase with average properties, and the discrete phase with the Eulerian-Lagrangian frame-work. Both approaches are compared to experimental results found in the literature. Both approaches show good agreement with the experimental results, with some advantage for the single-phase model both in processing time and in predicting heat transfer in the concentration range of 1-6% by volume. It was shown that, the heat transfer coefficient is greatly enhanced by increasing the particle concentration or decreasing the particle size. On the other hand, the usage of nanofluid causes a severe increase in the pumping power, especially with the increase in concentration and the reduction in particle size. Thus, a system optimization was suggested in order to raise the overall system efficiency for photovoltaic applications.

MPPT Control Strategy of Photovoltaic Cells Based on Duty Cycle Disturbance

Photovoltaic cell is a key part of solar power generation system, and whether its photoelectric conversion is sufficient is also called the maximum power point tracking problem, that is, photovoltaic cell MPPT. Different from the traditional MPPT control algorithm, this paper models and analyzes the output characteristics of solar cell. on this basis, proposes a fuzzy control algorithm based on duty cycle disturbance, and simulates it with MATLAB. The result shows the algorithm can well take into account the tracking speed and control accuracy when the external environment change.

Theoretically studying the optoelectronic properties of oligomers based on 2.7-divinyl-cabazole

This work consists of theoretically studying the electronic and optical properties of 9-(4-octyloxyphenyl)-2.7-divinyl-carbazole (PCrV) oligomers. This study has been undertaken using the density functional theory (DFT) method at the B3LYP/6-31G (d,p) level and BP86/6-31G (d,p) level of theory. To evaluate the PCrV-basis systems properties, the structural optimization without geometrical restrictions was performed on the total potential energy surface (TPES). In order to ensure good absorption of radiation, the interest was in increasing the efficiency of the organic photovoltaic cell. For this effect, the (HOMO-LUMO) gap energy of such compounds was reduced in terms of geometric and electronic structure. The BP86 functional gives good results at the energy gap level, while other parameters using the B3LYP functional give the best results.

Parameter Estimation of Photovoltaic Cell/Modules Using Bonobo Optimizer

In this paper, a new application of Bonobo (BO) metaheuristic optimizer is presented for PV parameter extraction. Its processes depict a reproductive approach and the social conduct of Bonobos. The BO algorithm is employed to extract the parameters of both the single diode and double diode model. The good performance of the BO is experimentally investigated on three commercial PV modules (STM6-40 and STP6-120/36) and an R.T.C. France silicon solar cell under various operating circumstances. The algorithm is easy to implement with less computational time. BO is extensively compared to other state of the art algorithms, manta ray foraging optimization (MRFO), artificial bee colony (ABO), particle swarm optimization (PSO), flower pollination algorithm (FPA), and supply-demand-based optimization (SDO) algorithms. Throughout the 50 runs, the BO algorithm has the best performance in terms of minimal simulation time for the R.T.C. France silicon, STM6-40/36 and STP6-120/36 modules. The fitness results obtained through root mean square (RMSE), standard deviation (SD), and consistency of solution demonstrate the robustness of BO.

ON THE CAPACITY OF SOLAR CELLS UNDER PARTIAL SHADING CONDITIONS

A photovoltaic system under uniform illumination conditions has only one global maximum power point, but this same panel in the case of partial shading conditions can have more maxima on the power-voltage curve. The motivation of this work are two-fold: to show nonlinear capacitance of solar cell and to propose a determination technique for partial shading condition. The author shows the results of measurements on a photovoltaic system under different lighting conditions. Shows the effect of capacitance on the shape of the response to excitation in the form of a load. The paper also shows which photovoltaic cell parameters influence the shape of the C-V curve.

Development of an Automatic Solar-driven Hand Sanitizing System (AHSS) using Proximity Sensors

Inception of COVID ’19 has brought new normal globally. Contagious nature of various infectious diseases necessitated frequent hand washing in order to reduce rate of contamination and community transmission. The need to contain the spread of COVID-19 necessitated the development of an Automatic Hand Sanitizing System (AHSS). The AHSS employed proximity sensor (IR) to sense the hand and actuate the 5V DC submersible pumps in charge of both water and sanitizer units of the AHSS. The DC voltage that powered the system was harvested from the Sun with the help of 5v Photovoltaic cell connected to a controlled charging circuit. The system responded to presence of user object within the active zone of the IR proximity sensors. This presence sends signal to the pumps to release either the Sanitizer/water. Evaluation based on Delay Time (DT), Average DT (ADT), True Positive (TP), False Positive (FP), Unable to Detect (UTD) and Accuracy (A) was conducted. The system was tested 180 times among students of School of Engineering, Federal Polytechnic, Ile-Oluji (FEDPOLEL). Results of evaluation indicate 12s, 180, 0.00, 0.00 and 100% for ADT, TP, FP, UTD and Accuracy, respectively. Accuracy of the designed AHSS was encouraging. An AHSS that can notify user about level of water and sanitizer, also test for presence of COVID-19 infection can also be designed and constructed.