Optimizing the Performance of a New Photovoltaic/Thermal System With a Serpentine Tube Heat Exchanger in Several Configurations for Heat and Electricity Cogeneration in Hot Climates: A Case Study in Jeddah, Saudi Arabia

Abstract

Abstract. The Gulf countries have tremendous solar energy potential due to the high intensity of sunshine throughout the year, enabling them to rely on photovoltaic (PV) systems as a sustainable and clean source of electricity generation. However, high environmental temperatures during the daytime pose significant challenges that reduce the performance of these systems. This research aims to introduce a practical and economical cooling technique to enhance the performance of solar PV systems under the hot climatic conditions of Jeddah, Saudi Arabia. To achieve the highest performance from the PV system, two different coolant configurations were evaluated with the proposed heat exchanger. In the first configuration (PVT-ST_W), the outer surface of the serpentine heat exchanger was insulated from the ambient, thus cooling was achieved by forced convection of water within the tubes. In the second configuration (PVT-ST_bifluid), the serpentine heat exchanger was exposed to the ambient, providing natural convection cooling, while cooling water was passed through the serpentine tubes, providing forced convection cooling. To demonstrate the feasibility of the proposed configurations, the results obtained were compared with data from a conventional PV-standard unit and with outcomes from previous studies. Three-dimensional numerical modeling of the proposed configurations was performed using ansys fluent to implement the computational fluid dynamics code. The results showed a significant reduction in the average cell surface temperatures for the two proposed configurations, PVT-ST_W and PVT-ST_bifluid, by 3.08% (9.8 K) and 4.79% (15.0 K), respectively. Both configurations significantly increased the total power output. However, if the system required electrical power production at the expense of thermal power, the second configuration should be used, while if the system required thermal power production, the first configuration can be used. The proposed PVT-ST_W and PVT-ST_bifluid improved the electrical output by 14.83% and 23.02%, and the electrical efficiency by 14.67% and 22.87%, respectively. The total heat gain of the PVT-ST_bifluid system was 12.95% higher than that of the PVT-ST_W system. The levelized energy cost was $0.23, $0.20, and $0.59/kWh for the PVT-ST_W, PVT-ST_bifluid, and PV-standard systems, respectively. The payback time for the PVT-ST_W and PVT-ST_bifluid systems was reduced by 228.84% and 249.98%, respectively.