To improve Solar energy gain by the photovoltaic (PV) modules, a novel double-axis Solar tracker was developed in the present study. The proposed system worked based on both active and passive methods of sun tracking using electromotor and gas actuator, respectively. The electromotor oriented the module in the east-west direction based on the principle of the chronology of the sun, and in the north-south direction, the change in the gas pressure, due to the temperature change, activated a pneumatic cylinder to rotate the module. The evaluation tests were carried out at the different modes of tracking (including east-west, north-south and double axis). The results showed that the available Solar energy on the PV module increased by 5. 03%, 33. 75% and 38. 78% using the tracker at the north-south, east-west and double axis modes, respectively. This, finally, improved electricity generation of the PV module by 4. 82%, 31. 43% and 36. 25%, respectively. Moreover, employing the tracker system led to an increase in operating temperature of the PV module. Based on the operating temperature of the module with the tracking system, it was proposed for using in the photovoltaic-thermal collectors. The designed system could track the sun trajectory with the accuracies of 0. 6% and 8% in the east-west and south-north directions, respectively.

Among different renewable resources technologies associated with Solar energies, photovoltaic (PV) systems have grown significantly. The produced power of a PV system is proportional to the Solar radiation and so due to the variation in the Solar radiation during the day and a year, the generated power of the PV farms changes too. Due to the rotational motion of the earth around itself during a day and also the transitional motion of the earth around the sun during the year, the amount and angle of sunlight on PV panels’ surface change. For enhanced amount of Solar radiation on PV panels, the Solar tracker can be used to place the Solar panels perpendicular to the sun's rays. Two kinds of Solar tracker systems including single-axis and double-axis trackers can be used in PV farms. In this paper impact of Solar trackers on PV farms’ reliability is evaluated. For this purpose, a multi-state reliability model is constructed for PV farms where failure of composed elements and change in Solar radiation intensity are considered. For determining the optimal states number and associated probabilities of this model, the XB index and fuzzy c-means clustering method are implemented. The suggested reliability model is applied for the adequacy assessment of power networks containing large-capacity PV farms. Besides, the impact of Solar trackers on reliability indices of power networks integrated with PV farms is investigated.

These days, societies' need for energy increased due to the expansion of societies, industries, and technology. The production of electricity from renewable energy sources such as Solar energy, which does not harm the environment and has little pollution, has attracted the attention of many researchers and engineers. This article will present a new plan for the dual polar axis Solar tracker, its design and construction in laboratory dimensions, and the experimental evaluation of its performance using the open-loop control method. For this purpose, after examining the advantages and disadvantages of the previous designs, a new and different conceptual design for the tracker is proposed. Among the features of the proposed tracker, we can point out the ability to combine, install and operate quickly and easily, the self-locking feature, and the ability to rotate 360 ​​degrees around both axes. This tracker has no restrictions for use in different geographical areas, including areas near the North or South Pole and in the early and late hours of the day when the direction of the sun's radiation is strongly inclined. In the following, the detailed design of the proposed detector and the presentation of the open-loop control method will be discussed. Finally, by conducting experimental tests, the production power of the proposed detector is evaluated in comparison with a fixed Solar panel. Based on the results, the electricity energy produced from the proposed Solar tracker is 49% more than the fixed Solar panel.

A sun tracker system, consists of two parts (opto-electronic and hydraulic), has been designed and fabricated to be used in Solar thermal power plant. In this paper various parts of the system including optical sensors, electronic circuits, computational control and mechanical lever have been explained and the operational mechanism of each one is discussed. The parabolic mirror used in this plant has 400 cm length, 570 cm width and 170 cm focal length. Rays falling parallel to the axis of mirror are reflected and collected at the focal point, while unparallel rays are diverted. To determine the rate of divergence, a three – dimensional equation of radiation path is written. Using a computational program in "C" language the error is calculated from "0" to "0.5" degree, for modifying the operational error of the optical system. The optical sensors detect the beam deviation from the mirror,s principal axis with a precision of 0.1 degree and transfer the necessary corrections to the active mechanical system of the hydraulic type. A three phase electromotor of 0.7 kW power and one thousand revolutions per minute controls the mirror movement.

IntroductionWith increasing the world's population, the demand for supply water resources is also increasing. Nevertheless, climate change has severely impacted the accessibility of fresh water resources. Consequently, researchers have been focusing on producing drinkable water from seas and oceans. Iran, with its significant levels of Solar radiation and access to open water from the north and south, is an ideal country for fresh water production. Using Solar water desalination systems is a reliable and cost-effective solution for producing drinking water from salt water sources. The purpose of this research is to enhance the performance of the Solar water desalination system by using the latent heat storage system and a Solar tracking system. In this experimental setup for fresh water production, water was used as the working fluid, while a parabolic collector functioned as the source of thermal energy.Materials and MethodsThe Solar water desalination system was designed and built on a laboratory scale at the University of Kurdistan, and then the necessary experiments were carried out. The flowing fluid (water) inside the spiral tube in the tank is pumped into the absorber tube of the parabolic collector. Inside the receiver tube, there is a spiral copper tube with a 7 cm pitch, which contains paraffin. The parabolic mirror reflects the sunlight onto the receiver tube, causing the working fluid, water, to heat up. The cooling process is achieved using a specific source located in the upper section of the distillation tank. In this case, the steam droplets in the tank hit the bottom surface of this cooling tank, which has the shape of an inverted funnel, leading to condensation. The study was conducted over four consecutive days, from 10:00 to 14:00, under identical conditions from August 24th to August 27th, 2022. It took place at the Renewable Energy Laboratory, University of Kurdistan in Sanandaj, Iran, and was conducted for three different volume flow rates of fluid: 1.9, 3.1, and 4.2 l.min-1 with phase change materials (PCM) and 4.2 l.min-1 without phase change materials (WOPCM); the pump’s maximum flow rate was 4.2 l.min-1. Variations of outlet temperature, thermal efficiency, desalination efficiency, and produced water were investigated under different conditions.Results and DiscussionThe results reveal that by decreasing the pitch of the spiral tube, there is an increase in the amount of heat captured, due to the increase in the Nusselt number. At the beginning of data collection, a significant amount of the energy that enters the receiver tube is absorbed by both the phase change material and the spiral tube inside the receiver and as a result, the initial air temperature is lowered. The highest temperature of salt water occurs when the fluid is flowing at a rate of 4.2 l.min-1, while the lowest temperature is observed at a flow rate of 1.9 l.min-1. With a flow rate of 4.2 l.min-1, the absorbent tube rapidly transfers the absorbed heat to the salt water chamber through the fluid. The input energy to the tank has increased from 1.53 to 2.83, 1.14 to 2.18, and 0.73 to 1.48 MJ for fluid flow rates of 4.2, 3.1, and 1.9 l.min-1, respectively. At a flow rate of 4.2 l.min-1, the thermal efficiency of the system without phase change materials (3.51%) is lower compared to the case with phase change materials (5.02%). Moreover, using a Solar tracking mechanism increased the thermal efficiency of the collector by 9.86% compared to the system using a photocell sensor. Based on the water quality values, it can be stated that the level of dissolved solids in the water sample has been significantly decreased. This indicates that the water can be used for drinking.ConclusionIn this research, the process of thermal changes in a Solar water desalination system using PCM was investigated. The obtained results demonstrate that the use of PCM improved the thermal efficiency of the collector and the water obtained from the current system is safe for consumption. Furthermore, by implementing a Solar panel tracking system, the efficiency of the Solar collector is improved.

Considering that most of the information used in cognitive processing is obtained from visual attention, studies in visual attention in cognitive sciences are essential. The eyetracking analysis is a research tool used to measure visual attention. Studies of consumer behavior showed a relationship between visual attention and consumer purchasing decisions. Eye-tracking technology is used to research consumer decision-making, marketing, and advertising and diagnose cognitive disorders.

IntroductionDespite the increasing penetration of renewable energy sources in recent decades, many countries are significantly dependent on fossil fuels. The emission of regional (such as oil spills) and global (such as global warming) environmental pollution is the result of the excessive use of fossil fuels. Considering the significant reduction in the investment cost of renewable resources, Development and exploitation of these resources is one of the effective solutions to overcome these problems. In 2020, about 3.1% of the world's electrical energy was supplied by photovoltaic panels. This amount of production has caused Solar energy to rank third among renewable energy sources after water and wind.  In the past years, the levelized cost of electrical energy has decreased remarkably. This reduction is due to the decrease in the investment cost of Solar power plant components, including photovoltaic panels. Although many papers have been published on the structure and control system of the Solar tracker, few have investigated the performance of these systems in cloudy and semi-cloudy days. In this research, the Solar tracker system developed is evaluated on cloudy and semi-cloudy days.Materials and methods The Solar tracker system investigated in this research uses a structure and a control system for the optimal placement of photovoltaic panels in two lateral - vertical and polar placements. Before this and in the researches of the authors of this article, this Solar tracker has been mentioned. The number of photovoltaic panels installed on this structure will be multiple of two. The investigated system is a multi-input-multi-output system. In order to increase the reliability of the system, this system is divided into two separate systems.In order to evaluate the performance of the Solar tracker, the power and electrical energy produced by photovoltaic panels installed on a mobile structure have been compared with a similar panel installed on a fixed structure with the ability to adjust the angle to the horizon. The installation angle of the panel on the fixed structure is adjusted on a monthly basis and has been chosen in such a way that the maximum electrical energy produced during that month is obtained.ConclusionThe comparison of the tracking system and a fixed structure showed that the tracker would produce less energy on some hours of a cloudy day. The reason is the defined limitation on LDRs to follow the sun. However, on sunny days, the tracker would receive adequate Solar radiation and be in optimal positioning. The results demonstrated this system increases electricity production by 18.2 % compared to the fixed one. 

A new fuzzy maximum power point tracker (MPPT) for photovoltaic systems is proposed. Fuzzy controller input parameters dP dI, D(dP dI) and variation of duty cycle (DDC) are used to generate the optimal MPPT converter duty cycle, such that Solar panel maximum power is generated under different operating conditions. A photovoltaic system including a Solar panel, a fuzzy MPP tracker and a resistive load is designed, simulated and constructed. The fuzzy MPP tracker includes a buck dc/dc converter, fuzzy controller and interfacing circuits. Theoretical and experimental results are used to indicate the advantages and limitations of the proposed technique.