Comparative Techno-Economic Analysis of Novel Closed-Loop Hydronic Cooling of PV Panels in Hot and Arid Regions

The elevated operating temperature of photovoltaic (PV) modules in hot and arid regions accelerates performance degradation, reduces electricity generation, and adversely affects long-term economic viability. This study presents a comprehensive long-term comparative thermo-economic assessment of a closed-loop hydronic PV cooling system integrated with an above-ground water tank (PV-AGWT) and a common PV system (PV-Com) under hot and arid climatic conditions of Basra, Iraq. A three-dimensional transient model was developed using COMSOL Multiphysics to evaluate the thermal and electrical performance of both systems. The numerical results were subsequently integrated with degradation, environmental, and economic models to assess long-term system performance over a 25-year project evaluation period. The results indicate that PV-AGWT system effectively reduces PV operating temperatures, leading to an average increase of 2.07% in monthly net energy output compared with PV-Com. The improved thermal regulation decreases the annual degradation rate from 1.458%/year to 1.001%/year, extending the operational lifetime from 16.5 to 24.03 years. For a 1 MWp PV power plant, the PV-AGWT system achieves an annual net power production of 1559.78 MWh, representing an increase of 27.53 MWh/year (1.80%) relative to PV-Com, while cumulative electricity generation reaches 33.80 GWh over the project lifetime. Economic analysis shows that both configurations are financially viable, with PV-AGWT system achieving a net present value of US$1.67 million, a discounted payback period of 5.49 years, and a levelized cost of energy of 0.06 US$/kWh. The findings demonstrate that integrating an above-ground water tank with a closed-loop hydronic cooling system can simultaneously improve PV thermal regulation, mitigate long-term degradation, and enhance lifetime energy and economic performance, although these benefits should be considered alongside the additional capital and O&M requirements of the cooling system.