The world’s energy consumption is outpacing supply due to population growth and technological advancements. For future energy demands, it is critical to progress toward a dependable, cost-effective, and sustainable renewable energy source. Solar energy, along with all other alternative energy sources, is a potential renewable resource to manage these enduring challenges in the energy crisis. Solar power generation is expanding globally as a result of growing energy demands and depleting fossil fuel reserves, which are presently the primary sources of power generation. In the realm of solar power generation, photovoltaic (PV) panels are used to convert solar radiation into energy. They are subjected to the constantly changing state of the environment, resulting in a wide range of defects. These defects should be discovered and remedied as soon as possible so that PV panels efficiency, endurance, and durability are not compromised. This paper focuses on five aspects, namely, (i) the various possible faults that occur in PV panels, (ii) the online/remote supervision of PV panels, (iii) the role of machine learning techniques in the fault diagnosis of PV panels, (iv) the various sensors used for different fault detections in PV panels, and (v) the benefits of fault identification in PV panels. Based on the investigated studies, recommendations for future research directions are suggested.

Several studies state that phase change material (PCM) improves the electrical power and efficiency of the photovoltaic (PV) module. To find the suitable PCM for tropical climatic conditions, multi-PCMs are examined simultaneously with melting temperatures of 31 °C, 35 °C, 37 °C, and 42 °C. In this study, PCM containers are integrated behind the PV module with a thickness of 50 mm. The performance of the multi PV-PCMs is monitored year-round and compared with PV-noPCM. The experimental results show that the selected four PCMs performed the cooling process autonomously in all the climates, such as PCM with a melting temperature of 37 °C and 42 °C enhanced the higher cooling rate in summer, and the same PCMs failed to achieve a higher cooling rate in winter. The lowest temperature drop was noted for pre-monsoon and monsoon seasons due to the low irradiance. On the other hand, the highest temperature drop of 16.33 °C is observed for pre-summer (March) and 15.7 °C, and 17.14 °C for summer (April) as compared to PV-noPCM. The results of the present investigation highlight the requirement for choosing the proper PCM melting temperature based on optimal year-round performance. Further, it is recommended that a single PCM melting temperature for cooling the PV modules year-round in tropical climates is inappropriate, and instead, a cascaded structure with different PCM melting temperatures is recommended.

Several studies have concentrated on cooling the PV module temperature (T_PV) to enhance the system’s electrical output power and efficiency in recent years. In this review study, PCM-based cooling techniques are reviewed majorly classified into three techniques: (i) incorporating raw/pure PCM behind the PV module is one of the most straightforward techniques; (ii) thermal additives such as inter-fin, nano-compound, expanded graphite (EG), and others are infused in PCM to enhance the heat transfer rate between PV module and PCM; and (iii) thermal collectors that are placed behind the PV module or inside the PCM container to minimize the PCM usage. Advantageously, these techniques favor reusing the waste heat from the PV module. Further, in this study, PCM thermophysical properties are straightforwardly discussed. It is found that the PCM melting temperature (T_melt) and thermal conductivity (K_PCM) become the major concerns in cooling the PV module. Based on the literature review, experimentally proven PV-PCM temperatures are analyzed over a year for UAE and Islamabad locations using typical meteorological year (TMY) data from the National Renewable Energy Laboratory (NREL) data source in 1 h frequency.

The solar photovoltaic (PV) system is emerging energetically in meeting the present energy demands. A rise in PV module temperature reduces the electrical efficiency, which fails to meet the expected energy demand. The main objective of this research was to study the nature of OM29, which is an organic phase change material (PCM) used for PV module cooling during the summer season. A heat transfer network was developed to minimize the experimental difficulties and represent the working model as an electrical resistance circuit. Most existing PV module temperature (T_PV) reduction technology fails to achieve the effective heat transfer from the PV module to PCM because there is an intermediate layer between the PV module and PCM. In this proposed method, liquid PCM is filled directly on the back surface of the PV module to overcome the conduction barrier and PCM attains the thermal energy directly from the PV module. Further, the rear side of the PCM is enclosed by tin combined with aluminium to avoid any leakages during phase change. Experimental results show that the PV module temperature decreased by a maximum of 1.2 °C using OM29 until 08:30. However, after 09:00, the OM29 PCM was unable to lower the T_PV because OM29 is not capable of maintaining the latent heat property for a longer time and total amount of the PCM experimented in this study was not sufficient to store the PV module generated thermal energy for an entire day. The inability of the presented PCM to lower the temperature of the PV panel was attributed to the lower melting point of OM29. PCM back sheet was incapable of dissipating the stored PCM’s thermal energy to the ambient, and this makes the experimented PCM unsuitable for the selected location during summer.

Photovoltaic–thermal (PVT) applications have been widely studied in recent years, though commercialisation has become critical due to their operational characteristics and size. In this study, a portable PVT system was developed for mobilisation with assistance from an organic phase-change material (PCM). Two different PCM composites were developed using the PCM with charcoal (PCM + C) and charcoal and metal flakes (PCM + C + M). Considering the portability of the PVT system, conventional metal-container-based PCM storage units were avoided, and the shape-stabilised PCMs (SS-PCMs) were fitted directly on the back surface of the PV module. Further, a serpentine copper tube was placed on the SS-PCMs to extract heat energy for hot water applications. It was found that PV_PCM+C+M exhibited a higher cooling rate, with peak reductions of 24.82 °C and 4.19 °C compared to the PV_noPCM and PV_PCM+C, respectively. However, PV_PCM+C exhibited a higher outlet water temperature difference of 11.62 °C. Secondly, an increase of more than 0.2 litres per minute showed a declining trend in cooling in the PV module. Considering the primary concern of electrical power generation, it was concluded that PV_PCM+C+M is suitable for PVT mobilisation applications, owing to it having shown the highest thermal cooling per 190 g of PCM and a 1-Watt (TCPW) cooling effect of 2.482 °C. In comparison, PV_PCM+C achieved a TCPW cooling effect of 1.399 °C.