The effects of row spacing and ground clearance on the wind load of photovoltaic (PV) arrays

The accuracy of wind loads is vital for the security and economy of PV power stations. The majority of existing studies focus on the importance of the tilt angle, wind direction, and interference effect on PV modules. However, very few studies investigate the effects of row spacing and ground clearance on wind loads of PV arrays, which probably have considerable influences. The present study combines numerical simulations and wind tunnel tests to explore the impact of row spacing and ground clearance on wind loads. The results reveal that the row spacing considerably influences wind loads, and the influence of ground clearance is inconsiderable. Increasing row spacing notably diminishes the shielding effect of the windward row on subsequent ones. The second row experiences the most noticeable wind load variation when row spacing changes, with the amplitude of wind load variation in the second row being two to three-fold that of the third to eighth rows. The change of ground clearance varies the vortex size and form but exerts an inconsiderable influence on wind loads. The reduction factor is defined to describe the wind loads after the third row, which is suggested to be 0.7 for all tilt angles (beta >= 15 degrees or beta <= - 15 degrees) in row spacing from chord length to 5 times chord length in the practice. It should be noted that the wind load on the second row may change the direction at different row spacing. When the row spacing is between double and triple chord lengths, the pressure and torque coefficients obtain the minimum in the present study.