Photovoltaic Installation - Captured on Film
By Greg Nowell, CCM RA

Sometimes you have the ability to take advantage of the opportunity knocking at your door. This was the case when our firm was asked to manage the planning and installation of a rooftop photovoltaic system for a LEED silver certified building. As more owners engage green building, and the use of PV, we wanted to capture the installation on film to use as a training tool for our staff and hopefully spread the knowledge of what it takes to install this system. Turns out it was easier than we expected.

The system was installed on a flat rubber roof requiring only one roof penetration to feed power and controls to the transformer located below. A slip sheet was installed under the panels to allow the array to expand and contract without any impact to the rubber roof. This also allowed us to keep the roof warranty intact with the roofing manufacturer.

The individual PV panels are actually fairly light weight since they are composed of a composite rigid insulation board (R‐10) that acts as the base for the wafer thin PV panel which comes adhered to the base. The base edges have a tongue and groove interlocking system that allows quick installation because the panels slip together and are not fastened to each other. Each panel has its own quick connect electrical connection which is daisy chained from one panel to another. The perimeter of the array consists of a continuous weighted edge that prevents wind uplifting of the system up to 140 MPH. Airplane guide wire is connected at the weighted edges and strung across the length and width of the entire array. This provides the laterally strengthening the system needs to become a unified structural element to resist wind loads and generally tie the system together.

The 76 panel, 2,600 square foot array utilized Sanyo Assy Tiles and has an output of approximately 26 kilowatts. The system, atop the Phillipsburg Early Childhood Center, was funded through a $260,000 grant by NJBPU and under the design leadership of the Design Resources Group as part of the LEED silver certification for the building.

For the skeptics concerned about the cost required to dismantle and reinstall the array when the roof needs to be replaced 20 years from now we did some cost calculations. Over a twenty year period that net payback to the owner which includes the reinstallation work at the time of reroofing is over $25,000; and that’s based on today’s cost of electricity in the New Jersey area. Since the assembly of the panels only requires two mechanics the labor cost is low. Now that you are familiar with PV system you actually see how it was installed. Just go to http://www.stanford-creative.com/solararray.html

Greg Nowell CCM AIA
Heery International
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Reproduced with permission of USGBC NJ Chapter