Three-dimensional multi-physics modelling and optimisation of a hybrid of radiation filtering and passive cooling strategy for floating photovoltaic systems.

This study presents the development of a three-dimensional multi-physics thermal model for a novel design of a floating photovoltaic system, which incorporates a natural convection cooling loop where the coolant also acts as solar radiation filter. The thermal model is employed to investigate the combined effects of the passive cooling loop and the radiation filtering of the cooling channel located above the photovoltaic module, by varying the height of the cooling channel and the spacing between connecting tubes, with a view at optimising the cooling loop geometry. Simulation results indicate that the combination of radiation filtering and passive cooling is remarkably effective at improving the electrical performance of the floating photovoltaic system, by filtering out, from solar radiation, the non-useful range of wavelengths for crystalline silicon photovoltaic cells and, at the same time, reducing operational temperatures. Specifically, the daily average temperature of the floating photovoltaic system can be reduced by up to 15 °C, leading to a 3% increase in electrical efficiency and a contribution in thermal convective cooling by up to 64.48%. Additionally, the system's performance is assessed under varying global solar irradiance levels, representing possible maximum and minimum conditions worldwide at any time of the year. The results demonstrate the practical feasibility of the proposed design, which can reduce the operating temperature of the solar panels even under minimum irradiance levels.