Surface Of Photovoltaic Modules Research Articles

A framework to identify guano on photovoltaic modules in offshore floating photovoltaic power plants

Guano are an important factor affecting the cleanliness of photovoltaic modules on floating solar power plants at sea. It can lead to a decrease in photoelectric conversion efficiency, power loss, and even the occurrence of “hot spots”, thereby causing damage to the components. Therefore, the segmentation and detection of guano are crucial for visual automation in the cleaning and inspection processes. However, the composition, density, and thickness of guano naturally vary, leading to inconsistent levels of transparency and color. The uneven intensity of guano images greatly reduces the accuracy of segmentation and detection. Addressing this issue, this study proposes a segmentation algorithm based on combining different color channels to segment guano on the surface of photovoltaic modules. The mean shift method is used for adaptive segmentation to facilitate the detection of guano. Furthermore, the segmentation results obtained by this method are introduced into the input space to improve the traditional Mask RCNN. In addition, this study successfully produced a dataset of guano on the surface of photovoltaic modules using on-site data collection and with the help of a platform built in-house in the laboratory. The experimental results on the self-constructed dataset demonstrate that the enhanced Mask R-CNN model has shown an approximate increase of 5.9% and 6.0% in mAP values for object recognition and segmentation compared to the traditional Mask R-CNN model. This indicates the effectiveness of the methodology proposed in this study.

Experimental investigation of nonuniform PV soiling

Photovoltaic (PV) module soiling, i.e., the accumulation of dust on PV module surfaces, poses several challenges to PV system performance. Among these challenges, the nonuniform deposition of soiling across the module surface has received scarce attention. Soiling is directly associated with an overall performance loss, but can also potentially give rise to localised hotspots that can lead to long-term PV module failure. Therefore, addressing the issues arising from this nonuniformity is not only important for optimising energy production, but also for enhancing system reliability, and ensuring the long-term operation of relevant power generation systems. In this study, the impact of nonuniform soiling on PV performance is investigated experimentally by examining soil deposition on the upper surfaces of low-iron glass samples. Samples positioned at four different tilt angles were collected on a monthly basis over a one-year study period. Since the horizontal samples were found to represent the worst-case conditions, the most soiled sample at horizontal tilt was divided into four zones, each housing a single monocrystalline solar cell and examined further. The findings reveal that the soiled sample experiences an average transmittance deterioration of 13% relative to a clean sample, and a maximum (relative) spatial variation of 4% between the four zones. These optical losses affect the amount of sunlight received by the cells, resulting in a power deterioration of ∼6–7% per 5% drop in transmittance. The soiled sample experienced an average temperature rise of 2 °C, and an average power output (and efficiency) reduction of 30% relative to the clean sample, and a maximum (relative) spatial variation of 7% between the zones. The 30% average power loss measured in this nonuniform soiling case is more than double that which would be expected theoretically for a transmittance loss of 13% but from uniform soiling, so these results highlight the importance of addressing PV soiling for optimal PV performance, and of accounting for spatial soiling nonuniformity.

Simulation of particle deposition on solar photovoltaic panels based on a new critical capture velocity criterion

Solar energy, as a clean energy source, is becoming increasingly important in the global energy mix. However, particle deposition on the surface of photovoltaic (PV) panels can significantly reduce their power generation efficiency. In this study, the collision-deposition behaviour between silica particles and the surface of PV modules is investigated. The impact process of 13 μm silica particles on the glass surface was recorded by using a high-speed digital camera at various incident velocities and angles. A particle dynamics model was developed to predict the critical capture velocity of particles at different incident angles. It was observed that the critical capture velocity of the particles decreases as the angle of incidence increases. Subsequently, a correlation equation was established between the incident angle and the critical capture velocity, serving as the deposition criterion. Computational Fluid Dynamics (CFD) numerical simulation was employed to simulate particle deposition on PV surfaces under different wind speeds and installation tilting angles. The simulation results demonstrate that the mass of 13 μm silica particles deposited on the surface of PV panels decreases with increasing wind speed. Moreover, under identical inlet wind speeds, the particle deposition mass exhibits an initial decrease followed by a subsequent increase as the installation tilt angle of the PV panel increases. The distribution pattern of particle deposition on PV panel surfaces is diverse; however, predominantly concentrated at the mid-bottom region.

Empirical and numerical-based predictive analysis of a single-axis PV system under semi-arid climate conditions of Pakistan

Power generation from fossil fuels is the biggest challenge in the next half of the century. Alternative power generation techniques such as solar photovoltaic (PV) show potential to act as a future fuel with a challenge to efficiently convert the harvested solar energy into electrical power. This investigation conclusively focused on setting a 2.160-kW solar PV system capable of working at a higher efficiency by developing a mechanical structure that optimizes power production and minimizes energy losses. In addition to that, solar PV system efficiencies at various tracking positions, performance coefficients during rainy and sunny days, and system degradation rates have also been investigated. The PVsyst v6.8 simulation tool was used to obtain the simulated results, which were compared with the actual experimental results. The parameters considered for the investigations include ambient temperature, irradiance, solar PV module surface temperature, solar PV voltage and current, wind velocity, and atmospheric turbidity. The solar PV system was evaluated based on two modes, namely, M1 (no tracking/fixed type) and M2 (manual tracking by changing the position of the solar PV system every hour). The predictive results obtained using PVsyst v6.8 concluded that total energy production from the installed system was 3,242 kWh/yr and 3,984 kWh/yr for M1 and M2, respectively. The performance ratio (PR), obtained from simulation, was 72% and 78% for M1 and M2, respectively, which was consistent with the experimental results, i.e., 70% and 72% for M1 and M2, respectively. Similarly, the power conversion efficiencies under standard temperature and conditions for both modes, simulated and experimental, were found to be 16.50% and 12.75%, respectively. The estimated degradation rate was observed in the range of −0.6% to −5.0%.

Solar Photovoltaic Energy as a Promising Enhanced Share of Clean Energy Sources in the Future—A Comprehensive Review

The use of solar energy is now a common and modern alternative that many countries throughout the world have adopted. Different studies on PV systems have been documented in the literature; however, several reviews focus excessively on particular facets of solar modules. In this paper, the literature on PV systems published between 2000 and 2023 was reviewed thoroughly. This review is structured in three main parts. Primarily, the main factors impacting dust deposition on solar modules are discussed. These include temperature, wind speed, inclination angle, location, climatic conditions, photovoltaic module surface characteristics, and dust characteristics. Many methods for mitigating and reducing dust as well as approaches to cleaning PV modules are also reviewed in this study. The many types of solar modules, together with their most important characteristics and operational effectiveness, are presented. As more solar photovoltaic panels expand their end of life (EOL), solutions are required to recycle and dispose of solar photovoltaic panels at the lowest economic cost and with the least environmental damage through reduced carbon emissions and greenhouse gases. Subsequently, this paper further reviews solar PV energy for a green environment and PV waste recycling and its costs. Moreover, integrating solar energy with other clean energy constituting an energy source for hard-to-reach areas and an alternative to fuel are discussed. Therefore, this comprehensive review of the use of photovoltaic systems for green energy production is helpful in an increased share of clean energy for various energy sectors in the future.

Analysis of the Deposition of Pollutants on the Surface of Photovoltaic Modules

Analysis of the Deposition of Pollutants on the Surface of Photovoltaic Modules

Experimental study on the effect of dust particle deposition on photovoltaic performance of urban buildings

The output characteristics of photovoltaic (PV) modules can be negatively affected by the density of snowfall in winter and ash accumulation in summer. In order to solve this problem, an experimental platform for PV power generation with four angles of 0°, 30°, 45° and 60° was built in Shenbei New District, Shenyang City, China. The characteristics of ash accumulation on the surface of PV modules were studied and analyzed by SEM and XRD. The effects of snowfall, ash accumulation density and PV module angle on the output power and power attenuation rate of PV modules were investigated. The experimental results show that snowfall had both positive and negative effects on PV modules. The output power of the PV module decreases as the ash density increases. Based on the dust coverage density and tilt angle in the test data, empirical formulas are proposed to predict the average power reduction rate.

Characterisation of soiling on glass surfaces and their impact on optical and solar photovoltaic performance

Photovoltaic (PV) module soiling, i.e., the accumulation of soil deposits on the surface of a PV module, directly affects the amount of solar energy received by the PV cells in that module and has also been suggested as a mechanism that can give rise to additional heating, leading to significant power generation losses or even physical degradation, damage and lifetime reduction. Investigations of PV soiling are challenging and limited. We present results from an extensive outdoor experimental testing campaign of soiling, apply detailed characterisation techniques, and consider the resulting losses. Soil from sixty low-iron glass coupons was collected at various tilt angles over a study period of 12 months to capture monthly, seasonal and annual variations. The coupons were exposed to outdoor conditions to mimic the upper surface of PV modules. Transmittance measurements showed that the horizontal coupons experienced the highest degree of soiling. The horizontal wet-season, dry-season and full-year samples experienced a relative transmittance decrease of 62 %, 66 %, and 60 %, respectively, which corresponds to a predicted relative decrease of 62 %, 66 %, and 60 % in electrical power generation. An analysis of the soiling matter using an X-ray diffractometer and a scanning electron microscope showed the presence of particulate matter with diameters <10 μm (PM10), which was the most prevalent in the studied region. The findings of this study lay the groundwork for research into soiling mitigation practices.

The Effect of Dust Deposition on the Performance of Photovoltaic Panels

Given the energy crisis and climate change due to pollution, and given that the largest emissions of greenhouse gases are produced by the energy industry, we must turn our attention to the efficient use of solar energy, which is the cleanest and most abundant of all renewable energies. In this paper, based on an analysis of the specialized literature, we studied the effect of dust accumulation on the surface of photovoltaic modules on some performance characteristics and on the efficiency of these panels and modules compared to the efficiency of clean modules. We analyzed the cause of dust accumulation and the influence of the tilt angles of the photovoltaic panels on the dust deposition rate. We highlighted the influence of atmospheric temperature, solar radiation, wind speed, and relative humidity depending on the density of the dust deposited on the surface of the photovoltaic panel, and we found a decrease in the efficiency of the panel based on the increase in dust density for slightly high values of solar radiation, wind speed, and relative humidity. We highlighted the reduction in CO2 emissions by replacing electricity from fossil fuels with solar energy. The efficient use of solar energy is a solution for the decarbonization of the energy sector.

Research on dust deposition of PV modules based on three-dimensional numerical simulation and its application in installation parameter optimization

Dust deposition on the surface of photovoltaic (PV) modules leads to a decrease in photoelectric conversion efficiency and output power. To identify the dust deposition factors and laws, scholars have conducted numerous field experiments or numerical simulations. However, few scholars have studied the mechanism of dust deposition with three-dimensional (3D) simulation models. The parameters affecting dust deposition vary in different geographical regions, which limits the applicability of research findings on dust deposition to specific geographical areas. To address these issues, this paper first proposes dust adsorption conditions on the surface of PV modules. Based on the main dust deposition factors, a 3D simulation model for dust deposition is established, and the accuracy and effectiveness of the adsorption conditions and simulation model are verified. Then, with a combined approach of orthogonal experiments and 3D simulation analysis, the main dust deposition factors and laws are analyzed. Finally, regional clustering is conducted by dust deposition factors, and the simulation results are applied to the regional optimization of installation parameters. The case study results show that the PV modules have a maximum power generation of 231.91 kWh with an optimal installation angle of 17° and an installation height of 0.5 m in the I category region.

An Approach Towards Performance Evaluation of Solar Photovoltaic Module through Energy and Exergy Analysis

The pressure on the agriculture sector has significantly grown due to the fast rising trend of global population growth, which is predicted to reach more than 9 billion by 2050. In the meantime, the issues related with emission of greenhouse gases (GHG) and the decreasing supply of fossil resources are eliminating traditional farming practices. The agriculture sector is looking to feed the increasing population in more sustainable way with the access of technology based on renewable energy. Solar energy is one of the most accessible types of renewable energy when applied to farm uses. Solar photovoltaic (PV) technology has been used to generate the necessary energy to operate number of equipment used in agricultural throughout the years, including drying of crop, irrigation through pumping, greenhouse and dairy farming. In present work, an attempt has been made to evaluate the performance of solar photovoltaic system. The parameters such as ambient temperature, panel temperature, open-circuit voltage, short-circuit current, energy and exergy efficiencies were determined during experiment. Energy and exergy efficiencies during the day was ranged from 10.11–13.35% and 10-13.29%, respectively. It has been found that the exergy efficiency of PV modules was significantly influenced by the temperature, and that the exergy efficiency may be increased by removing heat from the PV module surface.

Experimental study of the effect of fallen leaf shading on the polarization characteristics of photovoltaic modules

Coverings have an important impact on the output and safety of photovoltaic (PV) modules. However, due to the complex on-site environment and difficult identification, it is difficult to obtain timely and effective cleaning. In this paper, the optical polarization characteristics of fallen leaf are studied to find the difference for the PV modules with or without fallen leaves covered, which is one of the typical coverings, based on the basic theory of polarization imaging. Firstly, a polarimetric imaging platform with a SALSA camera for PV modules is built. Then, several experiments are conducted and the corresponding images of PV modules shaded by heather or camphor leaves are obtained. Finally, shaded by the impacts on the polarization characteristics of the PV module from fallen leaves, the waveband of the incident light, and the observation angle are analyzed. The results show that the optical polarization characteristics of PV modules at bands of 420 nm and 546 nm are significantly different from others, wherever there existed shading leaves or not; The degree of polarization decreases and then increases with the observation angle from 0° to 70° at 9:00–12:00 a.m. on sunny days; At 0° observation angle, the stokes parameter S_{0} of PV modules with or without fallen leaves has the greatest difference. HighlightsThe influence of fallen leaves on the polarization characteristics of PV modules is studied.The polarization characteristic parameter with the largest difference between the PV modules with and without fallen leaves is obtained.This parameter is more conducive to detecting fallen leaves on the surface of PV modules.

Revolutionizing Photovoltaic Systems: An Innovative Approach to Maximum Power Point Tracking Using Enhanced Dandelion Optimizer in Partial Shading Conditions

Partial shading (PS) is a prevalent phenomenon that often affects photovoltaic (PV) installations, leads to the appearance of numerous peaks in the power-voltage characteristics of PV cells, caused by the uneven distribution of solar irradiance on the PV module surface, known as global and local maximum power point (GMPP and LMPP). In this paper, a new technique for achieving GMPP based on the dandelion optimizer (DO) algorithm is proposed, inspired by the movement of dandelion seeds in the wind. The proposed technique aimed to enhance the efficiency of power generation in PV systems, particularly under PS conditions. However, the DO-based MPPT is compared with other advanced maximum power point tracker (MPPT) algorithms, such as Particle Swarm Optimization (PSO), Grey Wolf Optimization (GWO), Artificial Bee Colony (ABC), Cuckoo Search Algorithm (CSA), and Bat Algorithm (BA). Simulation results establish the superiority and effectiveness of the used MPPT in terms of tracking efficiency, speed, robustness, and simplicity of implementation. Additionally, these results reveal that the DO algorithm exhibits higher performance, with a root mean square error (RMSE) of 1.09 watts, a convergence time of 2.3 milliseconds, and mean absolute error (MAE) of 0.13 watts.

Experimental Measurement and Numerical Simulation on the Snow-Cover Process of Solar Photovoltaic Modules and Its Impact on Photoelectric Conversion Efficiency

The snow falling on the surface of photovoltaic modules tends to reduce the output power. In order to understand the process of snow accumulating on solar photovoltaic modules and reveal the impact of snow accumulation on photovoltaic conversion efficiency, the snow-cover process was simulated on the surface of photovoltaic modules with different tilt angles by computational fluid dynamics (CFD). On this basis, the relationship between the amount of snow and tilt angle was explored. The snow effect of photovoltaic modules on photoelectric conversion efficiency was studied by building a test platform. At the same time, a measurement platform of snow accumulation on photovoltaic modules and photoelectric conversion efficiency was constructed. Through the experiment of the relationship between snow thickness and snow sliding distance and the power generation efficiency of photovoltaic (PV) modules, the influence of snow thickness and snow area on the power generation efficiency of PV modules is discussed. The results show that the larger angle between the photovoltaic panel and the ground is adverse to the accumulation of snow on the panel. When the thickness of snow reaches 1 cm, the power generation efficiency of the entire photovoltaic module reduces to 7.1% of that as normal. At the same time, the sliding of snow on the photovoltaic panel improves the efficiency of photoelectric conversion. Through the analysis of numerical simulation and experimental results, targeted suggestions are made on how to improve the efficiency of power generation for photovoltaic power stations under snowy conditions, which may provide a reference for engineering work.

On the uncertainty of estimating photovoltaic soiling using nearby soiling data

The accumulation of dust on the surface of photovoltaic modules can reduce their performance and affect the cost competitiveness of this technology. This phenomenon is known as soiling and can be mitigated through appropriate corrective and/or preventive actions. In order to maximize its effectiveness, it is important to plan the soiling mitigation strategy even before the PV system is operational. This is typically done through a nearest neighbor approach, by estimating soiling using data from the nearest operational photovoltaic system. This work focuses on understanding the uncertainty related to this practice. For this purpose, the semi-variance function is used to study the dissimilarity between the soiling losses of two locations in California depending on their distance. The results show that, when the soiling loss at a nearby system is used to estimate soiling of a site, the uncertainty can be approximated to increase linearly at a rate of 0.08–0.10%/km up to 60 or 80 km. After this distance, the use of a nearest neighbor approach is no longer justified, as it produces an uncertainty as big as the average soiling loss of the sites in the dataset used in this study. In some conditions, uncertainties > 0% are found also for sites located within 25 km, meaning that even close-by systems might soil differently.

Photovoltaics literature survey (No. 181)

Photovoltaics literature survey (No. 181)

Experimental investigation of the soiling effect on the PV systems performance and the cleaning intervals in Oman

The trend toward diminishing dependence on fossil fuels as an energy source has become a government obsession, resulting in the acceptance of renewable energy as an alternative green energy source. Photovoltaic energy is considered the most viable renewable energy source in the MENA region due to the high solar irradiation level and the number of clear sky days during the year. However, environmental factors such as dust limit the optimum utilization of the source. In this paper, the effect of the accumulated dust on the Photovoltaic module surface has been studied for six months in Oman's weather conditions to suggest an economical cleaning interval. The experiment was conducted on a 5.85 kW grid-tie ground mount system with two strings of 9 modules in series. Two manual cleaning intervals have been applied on each string to observe the effect of the dust on the PV system performance. The results show that the dust accumulation reduced the PV modules' current performance by up to 28 %, with the average current output of the uncleaned string measured at 4.1 A compared to 5.6 A from the cleaned string. Based on the study results, the recommended economic interval in Oman is 8–12 cycles annually, and it is expected to increase in the summer compared to the winter season. This work offers valuable insight to investors, consultants, PV plant O&M companies, PV engineers, and researchers offering prosecutable strategies for optimizing PV system efficiency in Oman.

New models for the influence of rainwater on the performance of photovoltaic modules under different rainfall conditions

Solar photovoltaic (PV) technology is considered one of the most promising clean energy technologies. Dust accumulation on the surface of photovoltaic modules is one of the important reasons for the decline of photovoltaic system performance, and the influence of rainfall is particularly significant. The purpose of this paper is to investigate the influence of rainwater on the output power of photovoltaic modules under different rainfall conditions. In this paper, a prediction model for dust density under different inclination angles is established based on outdoor test data, and the control variable method is used to design three different PV module performance testing schemes under different rainfall conditions, and a dimensionless model for output power is proposed. Empirical models of global solar radiation are combined, and thus output power prediction models under different rainfall conditions are developed. It is found that rainstorm conditions (Rainfall 50–100 mm) increased the peak PV module output power by 16.1%–28.2% compared to light rainfall conditions (Rainfall less than 10 mm), with the rain showing better cleaning effects for PV modules with higher dust densities. It is worth noting that PV module surface dust does not necessarily have only a negative effect on system performance. The influence mechanism of rainwater on the output power of photovoltaic modules and the prediction model established in this paper is helpful in improving the prediction accuracy of the output power of photovoltaic modules under rainfall conditions, and thus the efficient cleaning strategy is formulated.

Deposition Characteristics of Aerosol Particles on the Surface of PV Modules: Numerical Study

AbstractThe deposition of aerosol particles can significantly affect the surface transmittance of photovoltaic (PV) modules and thus reduce photoelectric efficiency. With the aid of the control variable method, orthogonal experimental design, and stepwise linear regression method, a numerical simulation study of the deposition process of aerosol particles on the surface of a PV module is carried out in this paper. The influence laws of inflow wind velocity (v), particle diameter (d), installation angle (α), and particle concentration (c) on the deposition process of aerosol particles are analyzed, respectively. The deposition mechanism of aerosol particles on the surface of the PV module is disclosed, and the prediction model of deposition rate (n) is proposed. The results show that v, d, and c all positively affect n of the aerosol particles within the value ranges of each investigation variable in this study. α positively affects n of the aerosol particles when v is less than 3.65 m s−1. α negatively affects the n of the aerosol particles when v is larger than 3.65 m s−1. The prediction model could accurately predict the n of aerosol particles. This research has a theoretical guiding significance for the formulation process of cleaning strategies for the surface of PV modules.

Introduction of the rectangular hole plate in favor the performance of photovoltaic thermal solar air heaters with baffles

To further favor the performance of photovoltaic thermal solar air heaters with baffles, the simulated models of three types of photovoltaic thermal solar air heaters with baffles were established by Fluent software to analyze the effect of the arrangement of the rectangular hole plates on the flow and heat transfer characteristics of photovoltaic thermal solar air heaters with baffles. The results showed that the decrease in the intensity and the area of the separated vortex caused by the arrangement of the hole plate in photovoltaic thermal solar air heaters with baffles could decrease the pressure loss and increase the convective heat transfer coefficient between the air and the photovoltaic module surface. For the specific air volume rate ranging from 27.0 to 81.0 m3·h−1·m−2, compared with Type I, the pressure losses of Type II and Type III decreased by 6.1 % ∼ 17.4 % and 7.8 % ∼ 20.3 %, respectively. In addition, when the specific air volume rate ranged from 13.5 to 81.0 m3·h−1·m−2, compared with Type I, the power efficiency, the thermal efficiency and the exergy efficiency of Type III increased by 2.4 % ∼ 4.3 %, 12.9 % ∼ 20.0 % and 5.6 % ∼ 8.9 %, respectively. Given the above analysis, Type III had the lowest pressure loss and the highest efficiency. Thus, Type III was the optimal structure to improve the performance of photovoltaic thermal solar air heaters with baffles.