Tech Q & A: All About Aerocompact

Q: Are Aerocompact standing seam clamps needed every rib or 3 per module? 2 per module?

A: How many clamps and thus attachments are needed per module is dependent on the uplift forces that are present on the modules, which is based on the environmental conditions found at the site. Some of these conditions are the design wind speed of the site, the Exposure Rating of the building, the Occupancy Risk Factor of the building, and the building height. You may see that 3 or even 4 clamps are required for a module in some conditions. Conditions may vary throughout the array, where more are required in some places near the outside or the top of the array, and less are required near the inside or the lower portions of the array. Follow the Approved Engineering Report in all cases to ensure an array that will meet all rated conditions for which the system was designed for.

Q: Would the Aerocompact ground mount racking be cost effective/competitive with SnapNrack for residential applications?

A: We are currently designing and employing Aerocompact G15 and G20 ballasted ground mount racking for smaller applications including residential grid tied and off grid installations. They take up about the same space with similar tilt profiles. The SnapNrack system allows for higher wind and snow loads, and allows for install with tilt angles higher than 20 degrees, and can accomodate some uneven terrain. The Aerocompact racking in areas of relatively flat terrain would be a lower cost alternative to the SnapNrack, as one does not need to source and cut 1-1/2″ Schedule 40 pipe, dig foundation holes or grade beams, and then source and pour concrete for the vertical support posts. Installation times can be shortened thus from a 2-3 day event for a 8kW PV Array, to a one day event. There is also the option to employ ground screws instead of ballast blocks to secure the array, and thus improve the appearance of the system for a homeowner.

Q: What is the minimum Aerocompact ballasted system size for roofs and ground mounts?

A: The absolute minimum size system that can be done is 6 panels, in either a 2×3 or a 3×2 arrangement. However, this does come with some limitations, as oftentimes the ballasting requirements for a very small array is very large, compared to the panels that are installed. It is difficult to overcome the sliding forces with such a small array, and thus sometimes the design will not be allowed. This is especially true with high wind conditions often found in Exposure C or D conditions, or with higher building heights, and also when using the higher tilt angled racking solutions such as the 15 degree roof mount system, or the 20 degree ground mount system.

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