Wind Loads on PV Panels: Impact of Panel Size, Gap, and Roof

This study investigates the influence of photovoltaic (PV) panel sizes on wind-induced loads on residential gable roofs. The motivation arises from increasing industry demand to install larger PV panels on residential buildings, an area where current standards, such as ASCE 7, provide limited guidance—particularly for panels exceeding 6.7 ft (2.04 m) in chord length. With larger PV panel sizes gaining popularity, understanding the implications of these dimensions on wind pressures and structural integrity is essential for enhancing safety and refining design standards.This research builds on previous studies which primarily focused on gable roofs with low roof slope, a configuration for which aerodynamic behavior and wind loads have been previously evaluated. In those earlier experiments, three panel sizes were tested: small panels, constrained to the maximum sizes permitted by ASCE standards, along with two larger sizes to represent medium and large configurations. A gap width of 0.75 inches (19 mm) between panels and a 3:12 roof pitch were selected, reflecting typical residential installations. These studies yielded foundational data on wind-induced pressure coefficients (Cp) and force coefficients (Cf) for various PV panel configurations at moderate roof slopes, establishing baseline wind load estimations. Nonetheless, to increase confidence on the early findings, a steeper gable roof and additional gap limits between the panels are considered in the second phase of this study. This update aims to create a more comprehensive wind load database that will assist in the codification of the outcomes.In the current study, three panel sizes will be tested, each with a fixed width of 3.77 feet (1.15 m) and lengths categorized as Small, Medium, and Large—6.56 feet (2 m), 7.38 feet (2.25 m), and 8.2 feet (2.5 m), respectively. Additionally, both landscape and portrait orientations will be examined to evaluate the impact of installation direction on wind loads. A narrower panel gap width of 0.375 inches (9.5 mm) will be introduced to assess its influence on airflow and pressure distribution between adjacent panels. Finally, experiments will be conducted with a steeper 7:12 roof pitch, contrasting with the previously tested 3:12 pitch, to better understand how roof slope affects wind-induced panel loads.Experiments will be conducted at the NSF NHERI Wall of Wind (WOW) Experimental Facility using 1:20 scale models of residential gable roofs. The facility’s turntable will allow for precise control of wind direction, with testing conducted in 15-degree increments over a full 360-degree range to simulate a variety of environmental conditions. This thorough approach aims to capture the complex wind effects on gable roofs equipped with PV systems, providing a robust dataset of Cp and Cf values across all orientations and panel sizes. Wind flow interactions with different panel sizes, orientations, and gap widths will be monitored to quantify peak pressure coefficients and force coefficients, which are critical for evaluating structural demands on residential roofs.The outcomes of this study are expected to offer valuable insights into the behavior of wind-induced loads on larger PV panel installations, informing adjustments to wind load provisions in standards such as ASCE 7. By addressing a broader range of panel sizes and roof pitches, the research aims to support the development of design guidelines that accommodate larger PV systems without compromising structural safety. The results will be directly applicable to residential PV installations on slopped roofs, a configuration widely used in low-rise residential construction. This data is expected to enable engineers and designers to make informed decisions about PV panel sizing, orientation, and installation practices, ensuring that future installations are resilient to wind loads and contributing to safer, more durable residential solar energy solutions. This work will ultimately support the industry’s transition towards larger PV panels on residential structures by establishing scientifically grounded design recommendations aligned with real-world demands and environmental considerations.