Energy consumption patterns, the greenhouse effect, the depletion of fossil fuel supplies and fossil fuel price fluctuation all contribute to an increase in the use of renewable resources in energy generation units (Pranesh et al., 2019). Solar power, on the other hand, is one of the most widely available clean energy sources. Solar energy is typically used to generate heat energy and electric energy using thermal collectors and PV systems. While the use of solar energy has grown, some limitations, such as high installation costs (Fakouriyan et al., 2019; Srimanickam et al., 2015), low energy conversion efficiency (Srimanickam et al., 2017; Srimanickam and Saranya, 2021) and the need for storage systems due to supply and demand curves that differ (S. Christopher et al., 2021; Thakur et al., 2020) have a negative impact on its use in comparison to other renewable energy sources. An enormous amount of research articles on photovoltaic/thermal (PV/T) technologies have been published in an attempt to resolve the above said barriers (Giwa et al., 2020; Lamnatou et al., 2021; Reji Kumar et al., 2020).
A PV/T technology can meet both electricity and heat energy demand simultaneously and reduces the amount of space needed for installation as compared to traditional solar energy systems (Saitoh et al., 2003). By lowering the PV panels surface temperature, a better conversion efficiency can be attained. Different HTF flow techniques achieved the reducing surface temperature of the solar panel. For instance, (Kluth, 2008) explored the advantages of water as a cooling agent. For this reason, two small solar panel models were made. One model was left uncooled, while the others were cooled by a fan blowing water on it. It was observed that a solar panel with water cooling produces more power production compared to another one. Moreover, cooling the solar panel surface by spraying water with a fan is inefficient because the water would not be spread over the entire panel surface, leaving certain areas of the PV panels uncooled, and this approach often results in a significant amount of water loss. To reduce the heat at the panel's surface, (Odeh and Behnia, 2009) used a surface cooling system. A water system was installed on the PV panel surface to deliver water sprinkling, and the study resulted in a 15 % increase in production during the peak of solar radiation. For the months of June and December, (Bahaidarah, 2016) explored the cooling of a PV panel using jet impingement both experimentally and computationally. When compared to uncooled PV panels, the authors found that electric energy yield increased by 51.6 % in June and 49.6 % in December. (Eisapour et al., 2020) employed wavy tubes to investigate a PV/T collector's in terms of energy and exergy efficiency. The wavy tube improves energy and exergy efficiency by 6.06 % and 4.25 %, respectively, compared to the straight tube. (Farahat, 2004) looked into the electrical efficiency of a PV/T system that used both direct water and heat pipe cooling. When compared to a direct water cooling system, it is demonstrated that the heat pipe cooling technology can help in achieving improved electrical efficiency. (Rahimi et al., 2015) examined single and multi-header micro configurations for PV cell cooling. PV panels with multiple header configurations eliminated more heat and generate more electricity, than PV panels with a single header design.
The performance of a PV/T collector can be improved by using the appropriate circulating fluid (Huaxu et al., 2020; Sheikholeslami et al., 2021). For instance, (Prakash, 1994) investigated the performance of PV/T technology from two different circulating HTF viz air and water. According to the finding, when the water has been used as a cooling fluid, the thermal efficiency varied between 50 % and 67 %. As cooling water is replaced with cooling air, the enhancement ranges from 17 % to 51%. (Hissouf et al., 2020) investigated the effects of dispersed copper in pure water on PV/T collector. The electrical efficiency of copper nanomaterial dispersed in water improved by 1.9 % having a volume concentration of 2 wt % when compared to pure water result. The efficiency of a PV/T module using brine as the circulating coolant HTF was evaluated by (Saitoh et al., 2003). When the brine temperature was kept constant, the PV/T conversion efficiency increased as 10 % to 13 %, and the brine temperature at the outflow increased from 20°C to 40°C and the photo-thermal efficiency seems to be between 40 % and 50 %. In addition to the previous research, various numerical and experimental investigations were performed to reduce the surface temperature of PV using nanofluids as a coolant to improve energy efficiency and output power. (Al-Shamani et al., 2016; Al-Waeli et al., 2017; Bianco et al., 2018; Hjerrild et al., 2016; Sardarabadi and Passandideh-Fard, 2016; Yazdanifard et al., 2017).
Water has been shown to be more effective as a coolant in PV/T than air. Adding nano / micro additives in the coolant could enhance the conversion efficiency in the PV technology (Said et al., 2021, 2018). However, dispersing the particle for a large quantity of coolant HTF (water) is not practically and economically feasible. From the literature, it is understood that most of the experiments were conducted using the solar simulator as an energy source. PV panel's effect is varied based on solar radiation, surface temperature, and other factors such as shading, dust, panel height from the ground, etc (Dwivedi et al., 2020). The influence of above said parameters could not be predicted in the simulator based experimental setup. By considering the above-enhanced cooling techniques that have been made for PV panel, in this paper, initially, a PV system was fabricated with a serpentine flow pattern for cooling. The main advantages of the serpentine flow pattern are the HTF can have a high heat removal factor FR(ηo) for low mass flow rate compared to other flow patterns for the same condition(S. S. Christopher et al., 2021). Further, a fabricated PVT system is integrated with sensible TES for conducting a real-time experiment. A correlation was constructed for the PV/ STSC system based on the real time experimental data, and the proposed PVT system was created and modelled in TRNSYS, which is not available in the existence component type and validated with experimental data. Based on daily, monthly, and annual performance, the validated TRNSYS model is utilized to optimize the entire system to fulfil hot water and electricity requirements for a single residential building in Chennai.