Research on floating photovoltaic heat exchange mechanism and coupling with hydrodynamic and water temperature model

• A coupling model of floating photovoltaic heat exchange mechanism and hydrodynamic and water temperature software is proposed for the first time. • The coupling model constructed exhibits certain sensitivity and adaptability to key parameters. • Floating photovoltaics reduce water temperature, the long-wave heat flux emitted by the photovoltaic modules contributes to an increase in water temperature. • Using a section of the middle route of the South-to-North Water Diversion Project as a case, the coupling model predicts the optimal tilt angle of floating photovoltaics and water temperature fluctuations. The floating photovoltaic (FPV) industry has witnessed accelerated expansion globally, posing critical challenges for quantitative impact assessment on water environment and predictive computational framework development for numerical simulation. This study fills these gaps by establishing a heat exchange mechanism model of FPV module and achieving spatio-temporal coupling simulations with an open-source hydrodynamic and water temperature software. Given the model’s applicability, we analyzed the sensitivity of module temperature, output power, and water temperature to key parameters. Then, using the south section of the Zhanghe control gate in the middle route of the South-to-North Water Diversion Project as a case study, the module output power, module temperature and water temperature after FPV deployment are predicted. The optimal inclination angle of the FPV module varies with time, the optimal inclination angle for maximum annual output power is determined to be 26°. Short-wave radiation flux is intercepted 54.2 % by FPV. The total net heat flux of the water surface decreases, leading to a decrease in water temperature by approximately 0.39 °C. Additionally, long-wave heat flux is released by FPV module, which offset approximately 50 % of the water temperature decrease due to short-wave radiation deduction. The research could provide technical and theoretical support for assessing the characteristics of floating photovoltaics and their impact on the water environment.