Enhancing photovoltaic thermal (PVT) performance with hybrid solar collector using phase change material, porous media, and nanofluid

This study presents a novel and low-complexity cooling system designed to enhance the performance of Photovoltaic Thermal (PVT) systems integrated with a Hybrid Air-Water Solar Collector (HAWSC), termed traditional PVT-HAWSC systems. The research addresses the limitations of these systems, such as low heat transfer fluid outlet temperature, thermal exergy, thermal and electrical efficiencies, and thermal power. This is achieved by incorporating phase change material (PCM), porous media (PM), and multi-walled carbon nanotubes (MWCNT)-water nanofluid into the traditional PVT-HAWSC system, resulting in a modified PVT-HAWSC system. The modified system features a double-pass single-duct air solar collector with steel wool-PM and a sheet-tube water thermal collector integrated with paraffin wax-PCM. Experimental investigations were conducted under varying flow rates of air, water, and nanofluid. The performance analysis included exergy, energy, thermal, and electrical assessments. Results demonstrated that fluid type and flow rate significantly impact performance. The modified system with nanofluid reduced the PV panel surface temperature by 28 °C, compared to 22 °C without nanofluid. Additionally, the average daily improvements in overall efficiency, total thermal efficiency, and electrical efficiency were 16.49 %, 56.25 %, and 93.64 % for the modified system, compared to 12.80 %, 43.16 %, and 79.90 % for the traditional system. Total thermal energy gained and average daily exergy efficiency were 302.72 W and 14.32 % for the modified system, compared to 235.4 W and 14 % for the traditional system. The modified PVT-HAWSC system achieved lower levelized cost of energy (LCOE) of 0.043 $/kWh, a 4.36-year payback, 36.55 tons of CO₂ mitigation, and $529.98 in carbon credits.