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.

This study explores the depollution activity of a photocatalytic cementitious composite comprising various compositions of n-TiO₂ and CaCO₃. The photocatalytic activity of the CaCO₃–TiO₂ composite material is assessed for the aqueous photodegradation efficiency of MB dye solution and NO_x under UV light exposure. The catalyst CaCO₃–TiO₂ exhibits the importance of an optimal balance between CaCO₃ and n-TiO₂ for the highest NO_x removal of 60% and MB dye removal of 74.6%. The observed trends in the photodegradation of NO_x removal efficiencies suggest a complex interplay between CaCO₃ and TiO₂ content in the CaCO₃–n-TiO₂ composite catalysts. This pollutant removal efficiency is attributed to the synergistic effect between CaCO₃ and n-TiO_2, where a higher percentage of n-TiO₂ appeared to enhance the photocatalytic activity. It is recommended that CaCO₃–TiO₂ photocatalysts are effectiveness in water and air purification, as well as for being cost-effective construction materials.

Rise in PV module temperature (TPV) majorly drops the electrical output of the PV system. This research presents a novel cylindrical tube PCM matrix that is not in physical contact with the PV module back surface unlike the existing PCM based PV module cooling techniques. This contactless PCM matrix prevents the PV module from thermal and physical stress, also it blocks thermal energy re-conduction from PCM to PV module. While stored thermal energy from PCM retransferred to the PV module during off-sunshine hours and also when the PCM turns to liquid TPV starts to rise abruptly, this contactless PCM matrix minimizes these issues as PCM matrix receives thermal energy by the mode of radiation and convection; Besides, PCM matrix surface area is not enclosed with the PV module back surface area that reduces the thermal stress and re-conduction. Developed PCM matrix is integrated beneath the PV module at particular distances of 6 mm, 9 mm and 12 mm to optimize the spacing between PV module and PCM matrix. It is found that 6 mm spacing PCM matrix reduced the TPV maximum of 2.5 °C compared to 9 mm and 12 mm spacing. This TPV reduction enhanced the PV module electrical output by 0.2 % than PV without PCM and it is observed that 6 mm is an optimal spacing for the radiation source PCM matrix.

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.