Numerical Study of Wind Loads on Residential Roof-Mounted Solar Photovoltaic Arrays

Abstract

Residential rooftops offer attractive options for solar arrays since it makes productive use of otherwise unused space and are co-located with residential demand. However, the current installation practice in the solar panel industry is based on code (ASCE-7) that is intended to estimate the design wind loads on buildings and roofs and is not intended to apply to roof-mounted solar arrays. Conservative mounting approaches are likely to result in over designed and expensive mounting systems, while less conservative methods may jeopardize the integrity of the whole system and safety of the surrounding structure. One of the major challenges of producing affordable energy form solar photovoltaic arrays is the cost of the installation. Thus, understanding wind-induced aerodynamic loads in arrays of solar panels is an important part of designing appropriate mounting systems. This study addresses the wind load on a 1:12 scale model of a moderate (83.6 m2) residential structure with a roof pitch of 26.5° with two arrays of solar panels on one side. The wind angle is varied from 0 to 360 degrees to address front and back roof-mounted arrays. The flow is simulated using the incompressible Navier-Stokes equation and k–ε turbulent model. The wind load is estimated from numerically obtained wind-induced pressure coefficients. The model result is also compared to a roof with no panels. Depending on the air flow direction, complex maximum and minimum pressure locations are identified where the panels are exposed to extreme conditions.