Flow Control in Solar Photovoltaic Farms: Impacts on Soiling and Cooling

In utility-scale solar photovoltaics (PV), efficiency and panel-life drop with extreme heating, high winds, and wind-flung debris. Changes to panel configuration modify the hazard impacts by altering canopy turbulence and influencing wind loading, heat transfer and particle trajectories. Panel-mounted vortex generators (VGs) and flow control (FC) devices can promote panel cooling without costly system-level changes, but how these devices specifically affect PV panel surface cooling and particle transport is minimally known. Here we discuss the interplay of panel-scale turbulent structures and their influence on heat and debris transport, focusing on the influence of VG- and FC-imposed turbulence. For a model two-panel PV array, wind tunnel experiments considered a range of VG and FC designs subjected to neutrally-buoyant and, separately, inertial particle-laden flow (φ_v∈ [0 → 2.1 x 10^-5]). Time-resolved particle image velocimetry shows modified mean and spatio-temporal statistics with VG and FC presence. Spectral proper orthogonal decomposition uncovers variations in localized coherent structures, correlating to panel wake particle clustering. Results highlight the role of coherent structures in PV system transport and motivate panel-scale flow control toward potential hazard mitigation.