Impact of Wind Speed and Direction on Cooling of a Pontoon-Based Floating Photovoltaic System

Floating photovoltaics (FPVs) are gaining traction as a land-saving alternative to ground-mounted photovoltaics (GPV). A commonly cited advantage of FPVs is their potential for lower operating temperatures due to the cooling effect of water. However, existing literature shows that the thermal performance of FPV systems may not consistently exceed that of GPV systems, as it is influenced by technology and location. Consequently, studying the thermal properties of a range of FPV systems is crucial to optimize power output and enable accurate energy yield modeling for new sites. This work investigates the thermal properties and calculated heat loss coefficients, or U-values, associated with the Faiman model for an FPV system using Ciel & Terre's Hydrelio Air floats, located in a pond in South Africa. A dependence of U-values on wind direction was observed, with improved cooling when the wind approaches from the rear side of the system. The estimated U-value components were U0 = 21.6 W/m2·K and U1 = 3.60 W·s/m3·K for wind from the front and U0 = 19.4 W/m2·K and U1 = 7.10 W·s/m3·K for wind from the rear side. The impact of the observed cooling variation due to wind direction on system performance was also evaluated, revealing a 1.7% increase in median performance ratio when the wind originates from the rear side.