Special Issue "Photovoltaic Modules"

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "Solar Energy and Photovoltaic Systems".

Deadline for manuscript submissions: closed (31 March 2020).

Special Issue Editors

Prof. Dr. Filippo Spertino
Website
Guest Editor
Department of Energy, Politecnico di Torino, 10129 Torino, Italy
Interests: photovoltaic and wind power systems
Prof. Dr. Paolo Di Leo
Website
Guest Editor
Department of Energy, Politecnico di Torino, 10129 Torino, Italy
Interests: renewable energy technologies; electrical power engineering; power systems analysis

Special Issue Information

Dear Colleagues,

This Special Issue is dedicated to the photovoltaic (PV) modules, which are the main component of photovoltaic plants. In particular, the efficiency of the PV modules is even higher, exceeding the 20% threshold, while the cost has dramatically decreased in the last years; some years ago, this cost was 60–70 % of the total installation cost, now it is only 30–40 % of the same total cost. However, as the robustness of the cells inside the modules has been reduced together with their thickness (100–200 µm), the encapsulation process may be imperfect and, as a consequence, the presence of mechanical, electrical, and thermal defects may be increasing.

The contributions submitted to this Special Issue should deal with the following topics, as well as other potential topics that are not mentioned here:

  • Electrical mismatch of solar cell I–V curves due to imperfect sorting process, defects/failure of the solar cells, as well as partial shading.
  • Potential induced degradation and light induced degradation, visual defects like snail trails due to cracks and micro-cracks, EVA delamination and reduction of insulation resistance, and shunt defects inside the solar cells.
  • Techniques for fault-detection (e.g., electroluminescence).
  • Recycling techniques of the materials used in the encapsulation.
  • Cost–benefit analysis to evaluate the replacement of faulty PV modules.

Prof. Dr. Filippo Spertino
Prof. Dr. Paolo Di Leo
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • PV modules
  • photovoltaic plants
  • techniques for fault-detection

Published Papers (9 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Open AccessArticle
Single-Diode Models of PV Modules: A Comparison of Conventional Approaches and Proposal of a Novel Model
Energies 2020, 13(6), 1296; https://doi.org/10.3390/en13061296 - 11 Mar 2020
Abstract
In this paper, the seven traditional models of photovoltaic (PV) modules are reviewed comprehensively to find out the appropriate model for reliability. All the models are validated using the Matlab code and graphical comparisons between models are made. The accuracy and convergence of [...] Read more.
In this paper, the seven traditional models of photovoltaic (PV) modules are reviewed comprehensively to find out the appropriate model for reliability. All the models are validated using the Matlab code and graphical comparisons between models are made. The accuracy and convergence of each model is evaluated using the data of manufactured PV panels. Then, a novel model is proposed showing its consistent performance. The three most key parameters of the single-diode model are self-revised to adapt to various types of PV modules. This new method is verified in three types of PV panels’ data measured by the National Renewable Energy Laboratory (NREL), USA. The validated data show promising results when the error RMSEs’ range of the proposed model is under 0.36. Full article
(This article belongs to the Special Issue Photovoltaic Modules)
Show Figures

Figure 1

Open AccessArticle
Theoretical and Numerical Study of a Photovoltaic System with Active Fluid Cooling by a Fully-Coupled 3D Thermal and Electric Model
Energies 2020, 13(4), 852; https://doi.org/10.3390/en13040852 - 15 Feb 2020
Abstract
The paper deals with the three-dimensional theoretical and numerical investigation of the electrical performance of a Photovoltaic System (PV) with active fluid cooling (PVFC) in order to increase its efficiency in converting solar radiation into electricity. The paper represents a refinement of a [...] Read more.
The paper deals with the three-dimensional theoretical and numerical investigation of the electrical performance of a Photovoltaic System (PV) with active fluid cooling (PVFC) in order to increase its efficiency in converting solar radiation into electricity. The paper represents a refinement of a previous study by the authors in which a one-dimensional theoretical model was presented to evaluate the best compromise, in terms of fluid flow rate, of net power gain in a cooled PV system. The PV system includes 20 modules cooled by a fluid circulating on the bottom, the piping network, and the circulating pump. The fully coupled thermal and electrical model was developed in a three-dimensional geometry and the results were discussed with respect to the one-dimensional approximation and to experimental tests. Numerical simulations show that a competitive mechanism between the power gain due to the cell temperature reduction and the power consumption of the pump exists, and that a best compromise, in terms of fluid flow rate, can be found. The optimum flow rate can be automatically calculated by using a semi-analytical approach in which irradiance and ambient temperature of the site are known and the piping network losses are fully characterized. Full article
(This article belongs to the Special Issue Photovoltaic Modules)
Show Figures

Figure 1

Open AccessArticle
MPPT of a Photovoltaic Panels Array with Partial Shading Using the IPSM with Implementation Both in Simulation as in Hardware
Energies 2020, 13(4), 815; https://doi.org/10.3390/en13040815 - 13 Feb 2020
Abstract
This article presents a method for the Maximum Power Point Tracking (MPPT) of a Photovoltaic (PV) panels array with partial shading, applying an Improved Pattern Search Method (IPSM). The method is simulated in PSIM @ and then implemented in hardware in the loop [...] Read more.
This article presents a method for the Maximum Power Point Tracking (MPPT) of a Photovoltaic (PV) panels array with partial shading, applying an Improved Pattern Search Method (IPSM). The method is simulated in PSIM @ and then implemented in hardware in the loop system, emulating the PV array on an industrial computer (Speedgoat) that allows real-time emulations and the IPSM is applied in an Arduino DUE. The experiments were carried out with TP245S-20/WD, KYOCERA KC200GT, YINGLY SOLAR JS65, and MSX60 photovoltaic panels. The results are the proper MPPT with changes in partial shading over time, inducing the increase and decrease of the maximum power point. The results obtained are the search for the global maximum power point in a matrix of panels in which, due to partial shading, it might have several local maximum power points, and thanks to the IPSM algorithm, it always manages to find the global maximum power point. Finally, the results are compared with other methods where it was found that IPSM had faster answers. Full article
(This article belongs to the Special Issue Photovoltaic Modules)
Show Figures

Graphical abstract

Open AccessArticle
Experimental Evidence of PID Effect on CIGS Photovoltaic Modules
Energies 2020, 13(3), 537; https://doi.org/10.3390/en13030537 - 22 Jan 2020
Cited by 1
Abstract
As well known, potential induced degradation (PID) strongly decreases the performance of photovoltaic (PV) strings made of several crystalline silicon modules in hot and wet climates. In this paper, PID tests have been performed on commercial copper indium gallium selenide (CIGS) modules to [...] Read more.
As well known, potential induced degradation (PID) strongly decreases the performance of photovoltaic (PV) strings made of several crystalline silicon modules in hot and wet climates. In this paper, PID tests have been performed on commercial copper indium gallium selenide (CIGS) modules to investigate if this degradation may be remarkable also for CIGS technology. The tests have been conducted inside an environmental chamber where the temperature has been set to 85 °C and the relative humidity to 85%. A negative potential of 1000 V has been applied to the PV modules in different configurations. The results demonstrate that there is a degradation affecting the maximum power point and the fill factor of the current-voltage (I-V) curves. In fact, the measurement of the I-V curves at standard test condition show that all the parameters of the PV modules are influenced. This reveals that CIGS modules suffer PID under high negative voltage: this degradation occurs by different mechanisms, such as shunting, observed only in electroluminescence images of modules tested with negative bias. After the stress test, PID is partially recovered by applying a positive voltage of 1000 V and measuring the performance recovery of the degraded modules. The leakage currents flowing during the PID test in the chamber are measured with both positive and negative voltages; this analysis indicates a correlation between leakage current and power losses in case of negative potential. Full article
(This article belongs to the Special Issue Photovoltaic Modules)
Show Figures

Figure 1

Open AccessArticle
Experimental and Numerical Study on the Cooling Performance of Fins and Metal Mesh Attached on a Photovoltaic Module
Energies 2020, 13(1), 85; https://doi.org/10.3390/en13010085 - 23 Dec 2019
Cited by 1
Abstract
The electrical efficiency and durability of a photovoltaic (PV) cell degrades as its temperature increases. Accordingly, there have been continued efforts to control the cell temperature by cooling the PV module. Generally, passive PV cooling using heat sinks attached on the back of [...] Read more.
The electrical efficiency and durability of a photovoltaic (PV) cell degrades as its temperature increases. Accordingly, there have been continued efforts to control the cell temperature by cooling the PV module. Generally, passive PV cooling using heat sinks attached on the back of the PV module can improve the electrical efficiency. However, few experimental studies have evaluated the effect of the heat sink shape on PV cooling. Therefore, this study proposed a passive cooling technology using meshes made of iron and aluminum, and performed indoor tests using a solar simulator to analyze the cooling performance. The experimental results demonstrated that iron and aluminum meshes reduced the PV module temperature by approximately 4.35 °C and 6.56 °C, respectively. Additionally, numerical studies were performed using a computational fluid dynamics (CFD) simulation to compare the cooling fins and meshes. The numerical results showed that the cooling fins exhibited a better cooling performance than the metal mesh. However, meshes can be mass-produced and have a high structural stability against wind loads. Meshes are more likely be applied to PV systems than cooling fins if adhesion were improved. Full article
(This article belongs to the Special Issue Photovoltaic Modules)
Show Figures

Graphical abstract

Open AccessArticle
Detection of Typical Defects in Silicon Photovoltaic Modules and Application for Plants with Distributed MPPT Configuration
Energies 2019, 12(23), 4547; https://doi.org/10.3390/en12234547 - 29 Nov 2019
Cited by 1
Abstract
During their operational life, photovoltaic (PV) modules may exhibit various defects for poor sorting of electrical performance during manufacturing, mishandling during transportation and installation, and severe thermo-mechanical stresses. Electroluminescence testing and infrared thermographic imaging are the most common tests for checking these defects, [...] Read more.
During their operational life, photovoltaic (PV) modules may exhibit various defects for poor sorting of electrical performance during manufacturing, mishandling during transportation and installation, and severe thermo-mechanical stresses. Electroluminescence testing and infrared thermographic imaging are the most common tests for checking these defects, but they are only economically viable for large PV plants. The defects are also manifested as abnormal electrical properties of the affected PV modules. For defect diagnosis, the appropriate parameters on their I-V curves are open circuit voltage, photo-generated current, series resistance, and the shunt resistance. The health of PV modules can be assessed by calculating these values and comparing them with the reference parameters. If these defects are diagnosed in time, the power loss is avoided and safety hazards are mitigated. This paper first presents a review of common defects in PV modules and then a review of the methods used to find the above-mentioned parameters during the normal PV operation. A simple approach to determine the resistances of the equivalent circuit is discussed. Finally, through a modification in an ordinary maximum power point tracking (MPPT) algorithm, information about the state of health of PV modules is obtained. This method is effective, especially if applied to submodule-integrated MPPT architectures. Full article
(This article belongs to the Special Issue Photovoltaic Modules)
Show Figures

Figure 1

Open AccessArticle
A Novel Photovoltaic Array Outlier Cleaning Algorithm Based on Sliding Standard Deviation Mutation
Energies 2019, 12(22), 4316; https://doi.org/10.3390/en12224316 - 13 Nov 2019
Abstract
There is a large number of outliers in the operation data of photovoltaic (PV) array, which is caused by array abnormalities and faults, communication issues, sensor failure, and array shutdown during PV power plant operation. The outlier will reduce the accuracy of PV [...] Read more.
There is a large number of outliers in the operation data of photovoltaic (PV) array, which is caused by array abnormalities and faults, communication issues, sensor failure, and array shutdown during PV power plant operation. The outlier will reduce the accuracy of PV system performance analysis and modeling, and make it difficult for fault diagnosis of PV power plant. The conventional data cleaning method is affected by the outlier data distribution. In order to solve the above problems, this paper presents a method for identifying PV array outliers based on sliding standard deviation mutation. Considering the PV array output characteristics under actual environmental conditions, the distribution of array outliers is analyzed. Then, an outlier identification method is established based on sliding standard deviation calculation. This method can identify outliers by analyzing the degree of dispersion of the operational data. The verification part is illustrated by case study and algorithm comparison. In the case study, multiple sets of actual operating data of different inverters are cleaned, which is selected from a large grid-connected power station. The cleaning results illustrate the availability of the algorithm. Then, the comparison against the quantile-algorithm-based outlier identification method explains the effectiveness of the proposed algorithm. Full article
(This article belongs to the Special Issue Photovoltaic Modules)
Show Figures

Graphical abstract

Open AccessArticle
Performance and Design Optimization of a One-Axis Multiple Positions Sun-Tracked V-trough for Photovoltaic Applications
Energies 2019, 12(6), 1141; https://doi.org/10.3390/en12061141 - 23 Mar 2019
Cited by 3
Abstract
In this article, the performance of an inclined north-south axis (INSA) multiple positions sun-tracked V-trough with restricted reflections for photovoltaic applications (MP-VPVs) is investigated theoretically based on the imaging principle of mirrors, solar geometry, vector algebra and three-dimensional radiation transfer. For such a [...] Read more.
In this article, the performance of an inclined north-south axis (INSA) multiple positions sun-tracked V-trough with restricted reflections for photovoltaic applications (MP-VPVs) is investigated theoretically based on the imaging principle of mirrors, solar geometry, vector algebra and three-dimensional radiation transfer. For such a V-trough photovoltaic module, all incident radiation within the angle θ a arrives on solar cells after less than k reflections, and the azimuth angle of V-trough is daily adjusted M times about INSA to ensure incident solar rays always within θ a in a day. Calculations and analysis show that two-dimensional sky diffuse radiation can’t reasonably estimate sky diffuse radiation collected by fixed inclined north-south V-trough, but can for MP-VPVs. Results indicate that, the annual power output (Pa) of MP-VPVs in a site is sensitive to the geometry of V-trough and wall reflectivity (ρ), hence given M, k and ρ, a set of optimal θ a and φ , the opening angle of V-trough, for maximizing Pa can be found. Calculation results show that the optimal θ a is about 21°, 13.5° and 10° for 3P-, 5P- and 7P-VPV-k/ θ a (k = 1 and 2), respectively, and the optimal φ for maximizing Pa is about 30° for k = 1 and 21° for k = 2when ρ > 0.8. As compared to similar fixed south-facing PV panels, the increase of annual electricity from MP-VPVs is even larger than the geometric concentration of V-trough for ρ > 0.8 in sites with abundant solar resources, thus attractive for water pumping due to stable power output in a day. Full article
(This article belongs to the Special Issue Photovoltaic Modules)
Show Figures

Figure 1

Open AccessArticle
Study on the Cooling Effect of Attached Fins on PV Using CFD Simulation
Energies 2019, 12(4), 758; https://doi.org/10.3390/en12040758 - 25 Feb 2019
Cited by 3
Abstract
The issue of efficiency decrease according to temperature increase is a pending problem in the PV market. Several active and passive technologies have been suggested but few quantitative studies on the estimation of the cooling effect have been carried out. In this study, [...] Read more.
The issue of efficiency decrease according to temperature increase is a pending problem in the PV market. Several active and passive technologies have been suggested but few quantitative studies on the estimation of the cooling effect have been carried out. In this study, a CFD (computational fluid dynamics) simulation model was developed to analyze a passive cooling technology using fins attached to the back of the PV module. Furthermore, a method to improve airflow at the back of the PV module by forming slits in the frame was analyzed. The simulation model reproduced the indoor test that uses a solar simulator and the cooling performance was analyzed according to the shape of the fins and the presence of slits. In the simulation results, the surface temperature and expected electrical efficiency without cooling were 62.78 °C and 13.24% respectively under nominal operating cell temperature conditions. Moreover, the temperature reduced by approximately 15.13 °C because the fins attached at the bottom of the PV module increased the heat transfer area with airflow. Thus, the electrical efficiency according to the PV module temperature was predicted as 14.39%. Furthermore, when slits were installed between the fins, they increased the airflow velocity and accelerated the formation of turbulence, thereby improving the cooling performance of the fins. The simulation results showed that the temperature could be further reduced by approximately 8.62 °C at a lower air velocity. As the fins and slits can also reduce the non-uniformity of the temperature, they are expected to supplement the efficiency and durability reduction of the PV modules caused by the hot spot phenomenon. In addition, it was shown that slits in the frame could further improve the cooling performance of the fins at a low-velocity airflow. Full article
(This article belongs to the Special Issue Photovoltaic Modules)
Show Figures

Graphical abstract

Back to TopTop