Net Zero Library

San Diego opens its first net zero library, combining sustainable design and technological innovation

Earlier this year, the County of San Diego opened its first zero net energy building, the Alpine Library in Alpine, Calif. The new, $10.2 million, state-of-the-art facility combines sustainable design and technological innovation and is pursuing both LEED Gold certification and Living Building Challenge‘s Net Zero Energy Building Certification from the
International Living Future Institute.

The 12,700-square-foot library is four times the size of the original facility, and offers a variety of services, including daily story time, programs for all ages, and free access to a network of 42 million books, DVD movies and music CDs. The library also includes automated book check-out and returns, a MakerBot 3-D printer, study rooms, a resource room for programs and exhibits, an approximately 700-square-foot Friends of the Library bookstore, early learning Discover Zone provided in part by First 5 of San Diego, and special areas for tweens and teens.

The new library is located adjacent to the Alpine Community Center, which sold a portion of its property, along with parking lots, to the county. Construction on the design-build project began in late-2009 and it opened on May 21, 2016, with more
than 2,215 visitors on the first day. C.W. Driver, San Diego, was the general contractor, Ferguson Pape Baldwin Architects, San Diego, was the executive architect and Manuel Oncina Architects Inc., La Jolla, Calif., was the design architect.

Manuel Oncina, president, architect and principal designer at Manuel Oncina Architects, says the design goal was to attain the rigorous programmatic needs, fit the library into a tight site while respecting the existing oaks, respond to neighbors graciously, express an exciting, yet contextual architecture, and meet the client’s goals for excellent sustainable principles.

Building Strategies

Amanda Schultz, LEED AP, architect at Ferguson Pape Baldwin Architects, was the chief administrator of the sustainable element of the project. According to Schultz, to achieve net zero energy, all of the library’s energy is produced on-site through rooftop solar panels. Passive design strategies, such as building orientation, vertical and horizontal shade fins, deep roof overhangs, thermal insulation in the roof and walls, high-performance glazing, and more, help reduce energy to cool and heat the space.

As Oncina explains, his firm’s principal role was to design a building that met the programmatic needs of the county’s library department, by creating a form and volume that would engage the public with its interior, while creating excitement with the exterior. “In addition,” Oncina says, “the form had to deal with solar orientation, shading, daylighting, and offer enough roof area for photovoltaic cells.”

By orientating the long side of the building along the east-west axis, indirect daylight is maximized on the north façade and indirect, controlled daylight on the south, with minimal exposure on the east and west façades to post a challenge in overheating hours of the day. Ideal for the summer, outdoor reading spaces and the Poets Patio are oriented to the north, and are sheltered by roof overhangs, the building mass and oak trees, providing comfort to visitors. Optimizing thermal comfort and buffering sound travel to readers, the serrated building geometry increases the northeast-facing surface area that is less susceptible to overheating compared to western exposures and obstructs westerly prevailing winds.

Ideal for the library’s environment in an area of hot climates with mild winters, the designers maximized the north windows at the ground and clerestory levels, allowing indirect daylight to flood the space, while minimizing glare with even distribution, and energizing the marketplace, living room, adult, teen and children’s areas.

To shade the south, west and east façades with direct sunlight potential, the building features horizontal louvers, concrete vertical fins, deep recesses of storefront systems, roof overhangs and careful massing of building extensions. These result in filtered, diffused light, which is ideal for reading and viewing activities. To control the amount of light entering the northwest-facing façades, small, circular apertures were used.

On the northern exposure, the library features PPG Industries Inc.‘s high-performance Altantica and Solarban 60 glazing, which boasts a solar heat gain coefficient (SHGC) of 0.31, and on the south, east and west exposures, PPG’s Atlantica and Solarban 70XL glazing, which boasts a 0.27 SHGC.

A Model of Conservation

According to Oncina, “The biggest challenge was the correct orientation of the roof, which needed to provide an interesting interior form, in addition to providing enough area for the NZE requirements.”

Clark Dietrich Building Systems, West Chester, Ohio, supplied the steel framing for the library, which was chosen for its long spans with minimum interior columns. “[Steel framing] also allows for durability, extreme flexibility in form creatively, and responds well to seismic constraints,” Oncina explains. “The standing seam metal roof is also the choice material when it comes to durability, maintenance, aesthetics and thermal accountability.”

Louisville, Ky.-based Metal Sales Manufacturing Corp.‘s provided approximately 12,800 square feet of its standing seam metal roofing, and Chicago-based JamesHardie supplied approximately 6,000 square feet of its HardiePlank Lap Siding.

SunTerra Solar Inc., Novato, Calif., supplied a 72kW photovoltaic system located on the library’s southwest-sloping roof above the children and staff areas, which is optimally sited for solar generation with minimal environmental shading. The system is anticipated to generate 108,515 kWh per year, equating to an offset of 108 percent of the library’s anticipated annual energy use.

Rmax, Dallas, provided its TSX-8500 rigid polyiso insulation and Johns Manville, Denver, provided its formaldehyde-free fiberglass batt insulation. The exterior wall insulation is R-19 between 6-inch metal studs with R-5 continuous insulation. The roof contains R-20 insulation.

Plug loads and lighting are expected to account for half of the library’s energy use. Oncina explains that things like TVs, emergency lighting, sinks with automatic shut-offs, and book sorters with small transformers in them draw energy 24 hours a day, seven days a week, regardless of whether or not they’re in operation. “These phantom loads are singularly small but can add up to nearly 2 to 3 percent of the building’s energy use, which is significant when you’re dealing with a net zero facility,” he says. “Phantom loads are not automatically accounted for in an energy model, so the design team had to complete a finite analysis to put a value to each of these and ensure the corresponding amount of energy was offset through solar generation.”

Oncina notes that the Alpine Library is the third project for the client that has had the same team of builders and designers. “This combination allowed our team to hone our skills considerably and deliver an excellent product,” he says. “Far from irrelevant in today’s digital world, libraries have become community and social centers for multigenerational patrons and as such, demand architecture that is inviting, friendly, durable and sustainable. As the county’s first net zero energy building, the Alpine Branch is the epitome of the county’s facilities and a great example for bright young minds.”

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Alpine Library, Alpine, Calif.
Owner: San Diego County Library, San Diego
Executive architect: Ferguson Pape Baldwin Architects, San Diego
Design architect: Manuel Oncina Architects Inc., La Jolla, Calif.
General contractor: C.W. Driver, San Diego
Fiber cement board siding: JamesHardie, Chicago
Metal roof fabricator: Challenger Sheet Metal Inc., Santee, Calif., www.challengersm.com
Glazing: PPG Industries Inc., Pittsburgh, www.ppgideascapes.com
Insulation: Johns Manville, Denver, www.jm.com, and Rmax, Dallas, www.rmax.com
Metal roofing panels: Metal Sales Manufacturing Corp., Louisville, Ky., www.metalsales.us.com
Photovoltaics: SunTerra Solar Inc., Novato, Calif., www.sunterrasolar.com
Steel framing: Clark Dietrich Building Systems, West Chester, Ohio, www.clarkdietrich.com
Structural steel: South Bay Welding Inc., El Cajon, Calif., www.southbaywelding.com