Aerodynamic mechanisms for wind loads on tilted, roof-mounted, solar arrays

A wind tunnel study has been performed on roof-mounted solar arrays of two different panel tilt angles. One of the arrays was also placed on the ground in order to distinguish array generated aerodynamic effects from building generated effects. It is shown that there are two main mechanisms causing the aerodynamic loads: (i) turbulence generated by the panels and (ii) pressure equalization. For higher tilt angles, significant array generated turbulence increases the net wind loads, while for low tilt angles, pressure equalization dominates. In addition, it is observed that the presence of the building changes the aerodynamic loads substantially compared to ground-mounted systems. There is a complex interaction between building generated vortices and the flow induced by the array, which depends on building height, the setback of the array from the roof edge, and other building parameters.