Photovoltaic (PV) cells can absorb up to 80% of the incident solar radiation available in the solar spectrum, however, only a certain percentage of the absorbed incident energy is converted into ...electricity depending on the conversion efficiency of the PV cell technology. The remainder of the energy is dissipated as heat accumulating on the surface of the cells causing elevated temperatures. Temperature rise of PV cells is considered as one of the most critical issues influencing their performance, causing serious degradation and shortening the life-time of the cells. Hence cooling of PV modules during operation is essential and must be an integral part of PV systems particularly in sun-drenched locations. Many researches have been conducted investigating a range of methods that can be employed to provide thermal management for PV systems. Among these designs, systems utilizing air, liquid, heat pipes, phase change materials (PCMs), and thermoelectric (TE) devices to aid cooling of PV cells. This paper provides a comprehensive review of various methods reported in the literature and discusses various design and operating parameters influencing the cooling capacity for PV systems leading to an enhanced performance.
This study proposes a methodology to predict the self-extinction of electric arcs occurring in the series circuit between modules and power converters in photovoltaic systems, considering the ...influence of control strategies of the power converters on the electric arc. The study aimed to evaluate the main concepts of power conditioning employed in photovoltaic converters, ensuring behaviors similar to constant resistance, voltage, current, or power loads. Initially, the voltage–current characteristic of the electric arc is modeled with experimental data from tests using the electrodes described in the IEC 63027 standard. Then, the methodology is presented, which analyzes the intersection between the circuit model and the predictive range of the electric arc to anticipate self-extinction under different voltages, currents, electrode distances, and behaviors of the power converter in photovoltaic systems. The experimental results validate the developed methodology, especially in limit cases. The main results indicate that the implementation of current or power controls in static converters allows for the sustained arcing, even at voltage levels previously considered safe for photovoltaic systems. It is considered that these results can contribute to the improvement of standards regarding protections against series electric arcs, as well as offer new insights into effective control strategies of converters for extinguishing electric arcs, without the need for arc fault detection.
•Dc series arcs defined by standard IEC 63027 modeled experimentally.•Photovoltaic curve and converter control influence on series dc electric arc.•Observation that converter control scheme influences arc self-extinguishing.•Current or power-based controls sustain arcs at lower voltages.
This paper proposes an electric vehicle (EV) charge-discharge management framework for the effective utilization of photovoltaic (PV) output through coordination based on information exchange between ...home energy management system (HEMS) and grid energy management system (GEMS). In our proposed framework, the HEMS determines an EV charge-discharge plan for reducing the residential operation cost and PV curtailment without disturbing EV usage for driving, on the basis of voltage constraint information in the grid provided by the GEMS and forecasted power profiles. Then, the HEMS controls the EV charge-discharge according to the determined plan and real-time monitored data, which is utilized for mitigating the negative effect caused by forecast errors of power profiles. The proposed framework was evaluated on the basis of the Japanese distribution system simulation model. The simulation results show the effectiveness of our proposed framework from the viewpoint of reduction of the residential operation cost and PV curtailment.
This study aims to design a renewable energy system that can meet the desired electrical load of households with low energy cost, high renewable energy fraction and low CO2 emissions. Photovoltaic ...solar power systems used to electrify typical households in Iraq were investigated through simulation and optimisation. One-minute resolution simulations and optimisations were performed to determine the performance and net present cost of two photovoltaic power system configurations, namely (i) off-grid and (ii) on-grid solar photovoltaic power systems. Results show that the two systems exhibit excellent performance, but the on-grid photovoltaic power system requires cheaper cost compared with the off-grid photovoltaic power system. The total energy generated from the off-grid photovoltaic power system meets the desired electrical load of households and recharges the batteries, whereas the excess electricity from the on-grid photovoltaic power system feeds the grid. The two designed systems are environmentally friendly and economically viable. The total net present cost of the off-grid solution is $6,244, and its energy cost is $0.196/kWh. By contrast, the total net present cost of the on-grid system is $6,115, with energy cost equal to $0.183/kWh. The obtained results confirm the suitability of photovoltaic power systems for electrifying single households in addition to feeding the national grid.
•Photovoltaic power system for household application.•Simulation-based economic optimisation approach.•Local weather resources highly influence on the optimal design.•Established optimal Off/On grid photovoltaic systems configurations.•Promising solution to decrease CO2 emissions.
Cascaded multilevel converter structure can be appealing for high-power solar photovoltaic (PV) systems thanks to its modularity, scalability, and distributed maximum power point tracking (MPPT). ...However, the power mismatch from cascaded individual PV converter modules can bring in voltage and system operation issues. This paper addresses these issues, explores the effects of reactive power compensation and optimization on system reliability and power quality, and proposes coordinated active and reactive power distribution to mitigate this issue. A vector method is first developed to illustrate the principle of power distribution. Accordingly, the relationship between power and voltage is analyzed with a wide operation range. Then, an optimized reactive power compensation algorithm (RPCA) is proposed to improve the system operation stability and reliability, and facilitate MPPT implementation for each converter module simultaneously. Furthermore, a comprehensive control system with the RPCA is designed to achieve effective power distribution and dynamic voltage regulation. Simulation and experimental results are presented to demonstrate the effectiveness of the proposed reactive power compensation approach in grid-interactive cascaded PV systems.
•Integration of TE generators with a heat pipe-based PV module as a hybrid system is proposed.•Numerical transient modeling based on the energy balance equations of the system was ...performed.•Integration of TE generators with PV module aid operating the solar cells at a steady level in harsh conditions.
Photovoltaic (PV) cells are able to absorb about 80% of the solar spectral irradiance, however, certain percentage accounts for electricity conversion depending on the cell technology employed. The remainder energy however, can elevate the silicon junction temperature in the PV encapsulation perilously, resulting in deteriorated performance. Temperature rise at the PV cell level is addressed as one of the most critical issues that can seriously degrade and shortens the life-time of the PV cells, hence thermal management of the PV module during operation is considered essential. Hybrid PV designs which are able to simultaneously generate electrical energy and utilize the waste heat have been proven to be the most promising solution. In this study, theoretical investigation of a hybrid system comprising of thermoelectric generator integration with a heat pipe-based Photovoltaic/Thermal (PV/T) absorber is proposed and evaluated. The system presented incorporates a PV panel for direct electricity generation, a heat pipe for excessive heat absorption from the PV cells and a thermoelectric generator (TEG) performing direct heat-to-electricity conversion. A mathematical model based on the energy balance within the system is developed to evaluate the performance of the hybrid integration and the improvements associated with the thermal management of PV cells. Results are presented in terms of the overall system efficiency compared to a conventional PV panel under identical operating conditions. The integration of TEG modules with PV cells in such way aid improving the performance of the PV cells in addition to utilizing the waste-heat available, leading to enhanced output power. The system presented can be applied in regions with hot-desert climates where electricity is considered of a higher demand than thermal energy.
Solar energy is expected to be a significant contributor to meet the increasing global energy demand. Rooftop photovoltaic (PV) systems account for a substantial portion of the global solar energy ...potential. However, optimizing the size and layout of these systems remains challenging. Existing approaches either focus on maximizing energy generation, heavily restrict the space of potential layouts, ignore inverter-type implications, or neglect practical aspects, such as minimizing self-shading. This paper presents a mixed-integer programming (MIP) model to address these limitations for PV systems installed on flat rooftops. The proposed model optimizes the net present value (NPV) and can produce multi-azimuth layouts while accounting for practical considerations, including mitigating self-shading, and ensuring rooftop walkability. The proposed model is adapted for systems that utilize micro-inverters or string-inverters. Two case studies are conducted to evaluate the performance of the proposed model. In one case study, the model is applied to a residential area. It is numerically shown that in some instances of capital costs and billing policies, the use of multi-azimuth layouts could significantly improve the NPV compared to the use of single-azimuth layouts with parallel rows of panels. The proposed model solutions are compared to an existing optimized installation in the second case study. The proposed model multi-azimuth layout solution improves the NPV by 10.17%. When restricted to single-azimuth layouts, the proposed model produces the same design as that of the existing installation in only a few seconds.
•A novel model for optimizing the size and layout of rooftop PV systems is presented.•Sizing is obtained by optimizing the NPV of the PV system.•A graph representation allows the model to produce solutions with multi-azimuth layouts.•The produced solutions mitigate self-shading, ensure rooftop walkability, and consider inverter type.•Two case studies demonstrated the advantages of systems with multi-azimuth layouts.
The present work represents a detailed performance analysis of a 5-kW
p
on-grid solar photovoltaic rooftop system installed on a flat roof of a hospital building at a height of 12 m from the ground ...level, located at Perambalur (latitude 11° 23′ N and longitude 78° 93′ E), Tamilnadu, India. The daily, monthly and annual average performance parameters of the PV system including energy output, final yield, reference yield, array yield, photovoltaic array efficiency, system efficiency, inverter efficiency, performance ratio and capacity utilization factor have been analysed. The environmental benefit analysis and the payback period of the installed solar photovoltaic plant are also discussed. This solar photovoltaic power plant generates around 7144 kWh per annum of electrical energy, which is fed into the grid, and the annual average array, inverter, system efficiency, capacity utilization factor and performance ratio of the plant are found to be 12.15%, 97.12%, 11.72%, 16.31% and 76.83%, respectively, during the year 2019. The overall PV module electrical efficiency has been increased by 1.21% by applying the forced air circulation mechanism and 2.31% by applying the forced water circulation mechanism. Subsequently, the heat gained by the system can be utilized for heat load application. The installed solar photovoltaic power plant has a positive impact on greenhouse gas emissions with a reduction of 11.287 t of CO
2
, 8.86 kg of SO
2
, 18.50 kg of NO
x
and 485.792 kg of ash per annum. The water-based cooling in photovoltaics can potentially generate an output energy of 7310 kWh, which is relatively higher than the energy generated by the photovoltaic module with air cooling.
Faults in any components (modules, connection lines, converters, inverters, etc.) of photovoltaic (PV) systems (stand-alone, grid-connected or hybrid PV systems) can seriously affect the efficiency, ...energy yield as well as the security and reliability of the entire PV plant, if not detected and corrected quickly. In addition, if some faults persist (e.g. arc fault, ground fault and line-to-line fault) they can lead to risk of fire. Fault detection and diagnosis (FDD) methods are indispensable for the system reliability, operation at high efficiency, and safety of the PV plant. In this paper, the types and causes of PV systems (PVS) failures are presented, then different methods proposed in literature for FDD of PVS are reviewed and discussed; particularly faults occurring in PV arrays (PVA). Special attention is paid to methods that can accurately detect, localise and classify possible faults occurring in a PVA. The advantages and limits of FDD methods in terms of feasibility, complexity, cost-effectiveness and generalisation capability for large-scale integration are highlighted. Based on the reviewed papers, challenges and recommendations for future research direction are also provided.
•Different type of faults including affected components, causes and effects are reported.•Fault detection and diagnosis (FDD) methods of PVSs are extensively reviewed.•Advantages and limits of different FDD methods are illustrated and discussed.•A challenging issue in fault detection and diagnosis of PVS are reported.•Recommendations for future research direction in FDD methods are provided.
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