Last-Minute Photovoltaics: Prudent planning, plus a flexible approach to installation design, allows an architect to embrace an influx of PVs.
Based on what you have seen and read about this project, how would you grade it? Use the stars below to indicate your assessment, five stars being the highest rating.
When the Irvine, California–based architecture, design, and planning studio LPA began work on the Jerry Lewis High Desert San Bernardino County Government Center, the project team had no clue that the final product would include enough photovoltaics to produce almost 473,000 kilowatt-hours per year. The firm’s president Dan Heinfeld says, “The design intent was to always provide PV panels, whether now or in the future,” yet it was halfway through construction documentation when the now-eight-month-old government service center received Recovery Act funds to actually include them. Thanks to an Energy Efficiency and Conservation Block Grant as well as state incentives, there are photovoltaics encompassing 9,812 square feet of the 66,778-square-foot building's roof, and an additional 15,518 square feet of panels mounted on four independent canopy structures in its parking lot. They produce an estimated 61.9 percent of the facility’s needed electricity.
Heinfeld describes the strategies for optimizing a building for a photovoltaic installation had money not become available: “It’s orienting the building for optimal exposure; it’s finding ways to keep mechanical units off the roof. It’s making infrastructure like electrical closets large enough to contain inverters as well as the conduit you need to run to the roof—or wherever else there july be PVs.”
At the government center, which is located in Hesperia, California, LPA capitalized on its own planning. Rooftop panels are mounted to a pipe-and-rail system installed to float above the roof, while each parking-lot canopy comprises a series of cantilevers connected to a central column. The two installations link to separate inverters, and both are canted 17 degrees and facing directly south.
In designing these installations, LPA did not demand absolute control. Heinfeld says, “We spend our time making sure that the PVs on the roof are far enough away from the parapets or any other obstacles that would cast shadows, for example. But some manufacturers prefer their photovoltaics to be laid, others want an attachment, and so on: Since this was a public job, we came up with criteria drawings that solar providers could bid; when one was selected, we detailed the project based on that solution.” LPA works more directly with a manufacturer for a private-sector commission. Yet, in general, its process is to refine an installation system after the marketplace has revealed a source.
LPA would have pursued another sustainability strategy regardless of funding for PVs. “You really have to start with conservation first,” Heinfeld notes. Current energy models peg the government center as operating 22.7 percent more efficiently than Title-24 standards, which it achieved by a combination of good solar orientation minimizing east- and west-facing exposures, exterior shading devices that protect the south and west glazing, efficient mechanical systems, multiple daylighting techniques, an Energy Star roof, and thermal mass. “Conservation measures are the key to creating buildings that achieve high percentages of electrical production offset.”
share: more »