Search Results (30)

This review provides a comprehensive and multidisciplinary overview of recent advancements in solar tracking systems (STSs) aimed at improving the efficiency and adaptability of photovoltaic (PV) technologies. The study systematically classifies solar trackers based on tracking axes (fixed, single-axis, and dual-axis), drive mechanisms (active, passive, semi-passive, manual, and chronological), and control strategies (open-loop, closed-loop, hybrid, and AI-based). Fixed-tilt PV systems serve as a baseline, with single-axis trackers achieving 20–35% higher energy yield, and dual-axis trackers offering energy gains ranging from 30% to 45% depending on geographic and climatic conditions. In particular, dual-axis systems outperform others in high-latitude and equatorial regions due to their ability to follow both azimuth and elevation angles throughout the year. Sensor technologies such as LDRs, UV sensors, and fiber-optic sensors are compared in terms of precision and environmental adaptability, while microcontroller platforms—including Arduino, ATmega, and PLC-based controllers—are evaluated for their scalability and application scope. Intelligent tracking systems, especially those leveraging machine learning and predictive analytics, demonstrate additional energy gains up to 7.83% under cloudy conditions compared to conventional algorithms. The review also emphasizes adaptive tracking strategies for backtracking, high-latitude conditions, and cloudy weather, alongside emerging applications in agrivoltaics, where solar tracking not only enhances energy capture but also improves shading control, crop productivity, and rainwater distribution. The findings underscore the importance of selecting appropriate tracking strategies based on site-specific factors, economic constraints, and climatic conditions, while highlighting the central role of solar tracking technologies in achieving greater solar penetration and supporting global sustainability goals, particularly SDG 7 (Affordable and Clean Energy) and SDG 13 (Climate Action). Full article

The aim of this paper was to delve deeper into the nuances of incident solar irradiance on the photovoltaic field of a fixed tilt angle system versus a horizontal single-axis tracker. The fixed tilt angle system was used as a baseline for comparison. Three assessment indicators were analysed (annual energy gain ($AEG$), monthly energy gain ($MEG$), daily energy gain ($DEG$)). The procedure used comprised the following steps: (i) choice of solar irradiance estimation model; (ii) theoretical study; (iii) study under real operating conditions—for this purpose, an experimental setup was used; and (iv) comparison of these studies. The experimental setup was installed at the Department of Electrical Engineering of the University of Oviedo (Gijón, Spain) (latitude $43°{31}^{\prime }{22}^{″}$ N, longitude $05°{43}^{\prime }{07}^{″}$ W, elevation 28 (m) above sea level). Gijón is characterised by a temperate oceanic climate typical of Spain’s Atlantic coast, with cool summers and wet and mostly mild winters. The code assigned to Gijón under the Köppen climate classification is $C_{fb}$. The horizontal single-axis trackers that comprise photovoltaic power plants have three operating modes (Scenario 1). Some studies consider a unique mode of operation from sunrise to sunset (Scenario 2). The following conclusions can be drawn from the results obtained: (i) although the results obtained in the theoretical study and in the study under real operating conditions were different, a trend can be seen in the results; for example, the $AEG$ obtained was approximately $13\%$ and $8.5\%$ in the theoretical study and in the real study, respectively, in Scenario 1 and approximately $18\%$ and $10.5\%$, respectively, in Scenario 2; Scenario 2 obtained higher results than Scenario 1 in all the assessment indicators; but it must be considered that Scenario 1 is the real mode of operation; (ii) from March to September, the horizontal single-axis tracker generates more electrical energy; as this period contains the months of greatest solar irradiance, the horizontal single-axis tracker performs better annually; considering the theoretical study and Scenario 1, the highest value of $MEG$ was in June ($43\%$) and the lowest was in December ($-29\%$); when the study was considered under real operating conditions, the highest result was in July ($30\%$) and the lowest was in December ($-24\%$); (iii) on the days between 70 and 277 in Scenario 1, the horizontal single-axis tracker generated more electrical energy; on the other days the opposite occurred; taking into account the theoretical study, the highest and lowest $DEG$ values were $43\%$ and $-30\%$, respectively; when the study was considered under real operating conditions, the highest and lowest $DEG$ values were $58\%$ and $-47\%$, respectively. Full article

Inspired by C. Alexandru, to achieve a balance between tracking accuracy and equipment cost and between single-axis tracking brackets and dual-axis tracking brackets, a kind of quasi-biaxial solar tracker, whose approximate two-axis motions are driven by a single motor, is studied in this paper. Firstly, considering the changes in the total number of sunny days and declination angle in a certain period of time, the characteristic day of the tracker in this period is set. Then, based on the variations in the Sun’s azimuth and elevation angle on the characteristic day, a quasi-biaxial solar tracker mechanism is designed. Its azimuth angle movement is directly driven by a single motor, while the elevation angle movement is driven by the same motor through a bevel gear and a cam mechanism. The solar irradiance of the photovoltaic module of the solar tracker is analyzed using PVsyst software. Through 3D modeling-aided design, a prototype of the solar tracker is built and then relative experiments are conducted to study the performance of the quasi-biaxial solar tracker. Simulation analysis and physical model experiments show that the quasi-biaxial solar tracker works and achieves a relative compromise between tracking accuracy and cost. Full article

This paper presents an energy analysis of the influence of the movement limit of a horizontal single-axis tracker on the incident energy on the photovoltaic field. The procedure used comprises the following steps: (i) the determination of the periods of operation of a horizontal single-axis tracking; (ii) the analytical determination of the annual, daily, and hourly incident solar irradiance on the photovoltaic field; (iii) the validation of the model; and (iv) the definition of the evaluation indicators. The study focused on three photovoltaic power plants in Spain (Miraflores $PV$ power plant, Basir $PV$ power plant, and Canredondo $PV$ power plant). Four evaluation indicators (annual energy loss, daily energy loss, beam component, and diffuse component) and ten movement limits, ranging from $\pm 50$ (°) to $\pm 60$ (°), were analysed. In Spain, photovoltaic power plants usually have a movement limit of $\pm 60$ (°), which is why it has been called the current scenario. According to this study, the following conclusions can be drawn: (i) It is necessary to calculate the optimal movement limit for each site under study at the design stage of the PV power plant. Although the energy loss per square metre for not using the optimal boundary movement is small, due to the large surface of the photovoltaic field, these energy losses cannot be neglected. For example, in the Canredondo photovoltaic power plant, the limit movement is not optimised and the annual energy loss is 18.49 (MWh). (ii) The higher the range of the limiting movement, the shorter the duration of the static operating period. Therefore, when the current scenario starts the normal tracking mode (where the beam component is maximised), the other scenarios remain in the static mode of operation in a horizontal position, which impairs the incidence of the beam component and favours the diffuse component. (iii) The type of day, in terms of cloudiness index, prevailing at a given location affects the choice of the movement limit. If the beam component is predominant, it favours the performance of the current scenario. In contrast, if the diffuse component is predominant, it favours scenarios other than the current scenario. Full article

Solar trackers represent a significant advancement in enhancing the efficiency of solar energy collection. This study describes the development and implementation of a passive solar tracker featuring a single horizontal axis of rotation and an innovative guide slot mechanism. The tracker is designed to be used with solar radiation-capturing devices. The guide slot mechanism is specifically engineered for a designated date, location, and period to follow the solar trajectory accurately. A contact follower moves along the guide slot, which drives a tracker disk to rotate by the solar trajectory. The mechanism is activated by the movement of a liquid container attached to a spring, thereby storing potential energy. The container releases the liquid through a mechanical valve that regulates the container’s movement, while the guide slot mechanism converts this movement into controlled rotational motion, which is transferred to a mobile structure mounting the solar panel. Notably, the majority of materials utilized in this construction are recycled. Furthermore, the solar tracker proposed in this work is designed to be operable by individuals with limited prior knowledge on the topic, emphasizing the primary contribution of this study: its potential to revolutionize energy collection in developing countries and marginalized urban areas. No similar systems are found upon comparison with existing models in the literature. Experiments conducted with a static solar panel and the same panel integrated into the passive solar tracker revealed a 30.87% improvement in energy collection efficiency over static solar panels. Full article

Ecuador is grappling with a severe energy crisis, marked by frequent power outages. A recent study explored solar energy efficiency in the coastal city of Manta using an IoT real-time monitoring system to compare static photovoltaic (PV) systems with two single-axis solar tracking systems: one based on astronomical programming and the other using light-dependent resistor (LDR) sensors. Results showed that both tracking systems outperformed the static PV system, with net gains of 31.8% and 37.0%, respectively. The astronomical-programming-based system had a slight edge, operating its stepper motor intermittently for two minutes per hour, while the LDR system required continuous motor energization. The single-axis tracker using astronomical programming demonstrated notable advantages in energy efficiency and complexity, making it suitable for equatorial regions like Manta. The study also suggested potential further gains by adjusting solar positioning at shorter intervals, such as every 15 or 30 min. These findings enhance our understanding of solar tracking performance in equatorial environments, offering valuable insights for optimizing solar energy systems in regions with high solar radiation. By emphasizing customized solar tracking mechanisms, this research presents promising solutions to Ecuador’s energy crisis and advances sustainable energy practices. Full article

This study investigates the performance of isotropic and anisotropic diffuse models to estimate the total solar energy received on flat-plate collectors fixed on dual-axis trackers. These estimations are applied at twelve sites selected in both hemispheres with different terrain and environmental conditions. The diffuse (or transposition) models used in this study are the isotropic Liu-Jordan (L&J), Koronakis (KOR), Badescu (BAD), and Tian (TIA), and the anisotropic Hay (HAY), Reindl (REI), Klucher (KLU), Skartveit and Olseth (S&O), and Steven and Unsworth (S&U). These models were chosen because of their simplicity in the calculations and minimum number of input values. The results show that a single transposition model is not efficient for all sites; therefore, the most appropriate models are selected for each site under all, clear, intermediate, and overcast conditions in skies. On the other hand, an increase in the ground albedo in the vicinity of the solar installation can increase the annual inclined solar availability on a two-axis tracker by at least 9% on average. Further, a linear dependence of the annual inclined solar energy on the variation of the ground albedo was found. Also, a linear relationship exists between the annual diffuse-fraction and cloud-modification factor values at the 12 sites. Full article

This paper proposes a new technique for a single-direction solar tracker. The proposed design is based on a sun sensor system that controls the position of the solar panel. The sun sensors of the proposed design contain four photodiodes that are placed on the solar panel in specific angles and directions. The proposed system has several advantages such as the simplicity of implementing the system. This system combines the real-time tracking of sunlight and the low cost of applying a single-direction tracker. The prototyping experiment and Simulink MATLAB were applied to show the advantages of applying a single-direction tracker by following the angle of sunlight during the day. Real-time sun position and irradiation data were applied. The experimental results show that the proposed single-axis sun sensor PV tracker system generates around 20 more electric power than a fixed-structure PV system. Full article

Nearly Zero Energy Buildings (NZEBs) play a key role in the world energy transition. This is motivating the scientific community to develop innovative electrical and thermal systems characterized by very high efficiency to specifically address the energy needs of modern buildings. Naturally, the integration of the latest generation photovoltaic (PV) systems into buildings helps to satisfy this need, and, with this objective in mind, an innovative and highly efficient building-integrated photovoltaic (BIPV) system is presented and discussed in this paper. The proposed PV system is purpose-built to be fully integrated into a variety of buildings (preferably into their rooftops) and assumes the form of a PV skylight. It is based on a certain number of innovative rotating bifacial PV modules, which are specifically made to be installed “under-glass” within a custom-made transparent casing. Thanks to their properties, the PV modules can be rotated using a very low-power, reliable, and efficient mono-axial solar tracking system, fully protected against adverse atmospheric agents. Once the proposed PV skylight is fully integrated into a building, it generates electricity and, additionally, helps to improve both the energy performance and the aesthetic appearance of the building. The electricity generation and illuminance performances of the proposed PV skylight are experimentally tested using a low-power homemade prototype driven by different solar tracking logics and under different operating conditions; the most relevant results are summarized and extensively discussed. The main outcome of the experimental study is that the most effective performance of the PV skylight is obtained by installing, in its available surface, the maximum possible number of rotating bifacial PV modules, side by side and with no empty spaces between them. Full article

The increasing environmental concerns and dependence on fossil fuel-based energy sectors necessitate a shift towards renewable energy. Off-grid communities can particularly benefit from standalone, scaled renewable power plants. This study developed a comprehensive techno-economic framework, analyzed the objective metrics, and assessed the influence of economies of scale in solar PV power plants to electrify off-grid communities, taking Baluchistan, Pakistan, as a pilot case. Simulations and analyses were performed using the System Advisor Model (SAM). The results indicate a noteworthy reduction in the levelized cost of energy (LCOE) with increased power generation capacity. It was observed that utilizing bi-facial modules with single-axis tracking leads to a more cost-effective LCOE compared to the relatively expensive dual-axis trackers. The main cost factors identified in the analysis were capital costs, installed balance of plant (BOP), mechanical, and electrical costs. Notably, the disparity between the highest and lowest LCOE values across the six different power generation pathways amounted to approximately 38.5%. The average LCOE was determined to be 2.14 USD/kWh for fixed-mounted plants, 1.79 USD/kWh for single-axis plants, and 1.74 USD/kWh for dual-axis plants across the examined power generation capacity range. The findings can serve as a valuable benchmark, specifically for regional key stakeholders, in making informed investment decisions, formulating effective policies, and devising appropriate strategies for off-grid electrification and the development of renewable energy value chains. Full article

Solar energy is the cleanest and most abundant form of energy that can be obtained from the Sun. Solar panels convert this energy to generate solar power, which can be used for various electrical purposes, particularly in rural areas. Maximum solar power can be generated only when the Sun is perpendicular to the panel, which can be achieved only for a few hours when using a fixed solar panel system, hence the development of an automatic solar tracking system. Over the years, different solar tracking systems have been proposed and developed, and a few have been reviewed in the literature. However, the existing review works have not adequately provided a comprehensive survey and taxonomies of these solar tracking systems to show the trends and possible further research direction. This paper aims to bridge these gaps by extensively reviewing these time-based solar tracking systems based on axis rotation and drive types. Lessons learned from the comprehensive review have been highlighted and discussed. Finally, critical open research issues are identified and elaborated. Full article

The use of solar trackers can help increase the production and time period of electricity generation in photovoltaic power plants. Different types of trackers in terms of rotation mechanisms and sun tracking systems have been used in these types of power plants in recent years. In this article, a comparison has made between the electricity produced of fixed and tracking structures in a number of power plants which are located in different cities of Iran but in similar geographical locations. Following this, software modeling is used to evaluate various sun tracking scenarios in the design of sample power plants. Finally, a techno-economic analysis has been made to evaluate the decision-making regarding the construction of such power plants in Iran using this technology. Using east-west detectors has had a positive effect on increasing the production of power plants, especially in summer. Due to the higher initial costs of using this technology in the power plants, as well as the higher maintenance costs, the economization of the power plants’ business plan is extremely dependent on other economic conditions governing the project. Using trackers alone cannot lead to a better situation in a project’s lifetime. From the national point of view, if domestic companies can produce east-west single-axis tracking technology at an acceptable cost and provide related services in the long term, it would be beneficial for the power grid. One of the attractive proposals for the power plants under construction will be the use of this technology, because of additional electricity production in peak hours in summer. Annual experimental data from different tracking/fixed PV power plant have been used for the first time in this techno-economic investigations, they are validated with the simulation process, and the results have been predicted for a wide range of tracking scenarios. Techno-economic analyses of this type of power plant are an essential need for policy makers and investors in Iran’s energy market. Full article

After installing a solar panel system, the orientation problem arises because of the sun’s position variation relative to a collection point throughout the day. It is, therefore, necessary to change the position of the photovoltaic panels to follow the sun and capture the maximum incident beam. This work describes our methodology for the simulation and the design of a solar tracker system using the advantages that the orientation and efficiency of the PV panel offer due to the latitude and the number of hours of sunshine in the testing area. This proposed methodology is experimentally validated through the implementation of a single-axis solar tracker at a specific location (36.261° latitude), which allowed the incorporation of a high-availability tracking mechanism, low precision, and low cost. Based on the results, the feasibility of this type of solar tracker for latitudes close to 36° was demonstrated, as this tracking system costs less than traditional commercial systems. Furthermore, this system increased the collection efficiency compared to a fixed device. Our results provide an excellent platform for engineering technology researchers and students to study the design theory of a sun-tracking solar system. Full article

The problem of 3D gaze estimation can be viewed as inferring the visual axes from eye images. It remains a challenge especially for the head-mounted gaze tracker (HMGT) with a simple camera setup due to the complexity of the human visual system. Although the mainstream regression-based methods could establish the mapping relationship between eye image features and the gaze point to calculate the visual axes, it may lead to inadequate fitting performance and appreciable extrapolation errors. Moreover, regression-based methods suffer from a degraded user experience because of the increased burden in recalibration procedures when slippage occurs between HMGT and head. To address these issues, a high-accuracy 3D gaze estimation method along with an efficient recalibration approach is proposed with head pose tracking in this paper. The two key parameters, eyeball center and camera optical center, are estimated in head frame with geometry-based method, so that a mapping relationship between two direction features is proposed to calculate the direction of the visual axis. As the direction features are formulated with the accurately estimated parameters, the complexity of mapping relationship could be reduced and a better fitting performance can be achieved. To prevent the noticeable extrapolation errors, direction features with uniform angular intervals for fitting the mapping are retrieved over human’s field of view. Additionally, an efficient single-point recalibration method is proposed with an updated eyeball coordinate system, which reduces the burden of calibration procedures significantly. Our experiment results show that the calibration and recalibration methods could improve the gaze estimation accuracy by 35 percent (from a mean error of 2.00 degrees to 1.31 degrees) and 30 percent (from a mean error of 2.00 degrees to 1.41 degrees), respectively, compared with the state-of-the-art methods. Full article

Today, the world continuously investigates the promising potential of advanced and optimized technologies for harvesting green renewable energy sources, such as a solar tracking system (STS). This study presents an actual implementation of a single-axis solar tracking system (SAST), where an azimuth control scheme is developed to precisely follow the sun’s orientation. This is demonstrated by computing in real-time the optimal azimuth angle based on the actual altitude, date, and time using an embedded microcontroller. At the same time, experimental comparisons using the azimuth-based control method compared with the proportional, integral, derivative (PID) control scheme and fixed-tilt PV systems (FTPV) are derived. Experimental results show that the developed azimuth solar tracker can autonomously follow the sun’s orientation primarily from time and location-based information and independent from the actual solar irradiance. Nevertheless, the electrical energies gained from all three tested systems revealed that using the sensor-based STS would increase the net energy production by 12.68% compared to the azimuth-based SAST, with an energy production increase of 7.7%. In addition, energy consumption by the azimuth-based STS is 65% greater than the energy consumption of a sensor-based STS due to the continuous movements of the tracker, regardless of the increase or change in power production within short periods. Full article