Experimental and optimization study of nanofluid utilized PVT systems with hydrocarbon based PCM: An Energetic-exergetic approach

Abstract

Cooling of photovoltaic thermal (PVT) systems is crucial for enhancing electrical efficiency by reducing the operating temperature of photovoltaic modules. Elevated temperatures negatively affect the performance of PV cells, leading to a decline in energy conversion efficiency. Photovoltaic thermal (PVT) systems, hybrid technologies that generate electricity and heat, are crucial for efficient energy conversion. This study uniquely explores the performance of a PVT system by integrating phase change materials (PCMs) and nanofluids in PVT systems combined with optimization analysis. By combining these advanced cooling methods, both electrical and thermal efficiencies are significantly optimized, demonstrating the potential for improved energy conversion in PVT systems. Within this scope, three identical systems-water-cooled, nanofluid-cooled, and a combination of nanofluid cooling with PCM-were analyzed regarding electrical, thermal, and exergy efficiencies. Identical panels were placed side by side and tested. Additionally, an optimization analysis has been conducted to enhance the performance of each panel by evaluating the thermal and electrical efficiency values obtained from experimental data based on system parameters and levels. In addition, thermogravimetric analysis and differential scanning calorimetry were conducted to determine the melting point of the Hydrocarbon-Based PCM. Compared with traditional methods, these analyses conducted in conjunction with the experimental study provide a more reliable basis for performance evaluation studies of PVT systems. The results of the experimental study showed that Nanofluid-Integrated PVT with Hydrocarbon-Based PCM achieved 11.7 %, 11.6 % and 10.6 % higher electrical efficiency, overall exergy and electrical exergy respectively, compared to the water-cooling method. Additionally, a 6.6-fold increase in thermal efficiency and a 4.4-fold increase in overall efficiency were observed. Similarly, compared to the nanofluid cooling method, this combination provided 4.9 %, 5.9-fold and 3.47 % improvements in the electrical, thermal and overall exergy efficiencies metrics. The results of the optimization analysis revealed that the combination of PCM and nanofluids ensures greater stability in electrical efficiency values under high-temperature differences. It was also observed that solar irradiance is the most influential parameter affecting efficiency. The obtained results demonstrate that the nanofluid-cooled system integrated with PCM has a significant impact on enhancing the performance of PVT systems. The combined use of nanofluid and PCM considerably improves all efficiency parameters.