Chasing Net-Zero: A school for students with learning differences reaffirms its core values with a new campus.
Design for the Chartwell School overlooking Monterey Bay in Seaside, California, began with the needs of its grades 1-8 students with learning differences. This meant placing a special focus on indoor-environmental quality, connection to the outdoors, and building educational opportunities into the design. “These students come with a challenged educational experience, and you want to give them every advantage,” says Scott Shell, AIA, a principal with EHDD Architecture in San Francisco. Early conversations between the design team and school representatives aligned everyone around the idea that high-performance education and high-performance buildings were a natural fit.
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Chartwell’s new $9.2-million campus is perched on a hilltop above Monterey Bay, on the site of the decommissioned Fort Ord military base. A native coastal oak woodland that the school chose to protect defines the edges of the campus. School activities are divided among several buildings laid out in parallel with longer northern and southern facades for optimal daylight access. Between the buildings, outdoor courtyard spaces invite play and outdoor instruction, and the site landscaping includes an educational “science garden.”
Conscious of tight water resources, the team built water conservation into the design and then took it one step further: “We said, ‘Let’s make the water story part of the larger educational story,’” Shell explains. In addition to dual-flush toilets, waterless urinals, and low-flow lavatories installed indoors, the team devised a rainwater catchment system that directs rainfall from rooftops into a 9,000-gallon cistern and back into the buildings for toilet flushing. In the wet season, a sluice in the courtyard diverts excess water from the cistern to the science garden, offering a visible lesson about water conservation and an opportunity for play. “It’s amazing what kids can learn about water just by playing in it,” Shell observes.
Classrooms are designed to optimize both daylighting and natural ventilation. Large operable windows and opposing clerestories balance natural light, minimize contrast and glare, and encourage cross-ventilation. In mechanical ventilation mode, fans in each classroom are connected to CO2 sensors and equipped with switches so that teachers can regulate ventilation to meet individual classroom needs. In the multi-purpose building, floor-to-ceiling, garage-style windows invite natural light into the open assembly space and create a striking indoor-outdoor environment when opened.
The team’s choices of building materials were facilitated, Shell says, by a fast-growing market for local and salvaged wood in California. Interior wood was salvaged from the Fort Ord barracks, while wine casks were reused for the exteriors. A local cypress trunk was incorporated into the design as both a structural support and a creative focal point. Standard lumber dimensions were utilized in the design, which helped the team reduce the amount of wood in the buildings by 30 percent—a savings that more than paid the premium for FSC-certified wood, Shell estimates.
Another educational opportunity presented itself in designing for disassembly, which involved creating exposed utility corridors near ceilings, rather than drilling through studs (thus keeping the lumber salvageable). Not only do the exposed utilities allow for easier maintenance, but students see how services are delivered to their classrooms. “We just made things visible,” says Shell.
Natural ventilation and Seaside’s mild climate make a mechanical cooling system unnecessary; radiant-floor heating provides comfort in winter. A connected lighting load below one watt per square foot keeps the electricity demand to a minimum. The team sized the photovoltaic (PV) array to meet 100 percent of the predicted annual electric needs based on energy modeling and comparisons to similar high-performance schools in the region.
In the project’s first two years of operation, however, the goal of net-zero electricity remains elusive. After measurement and verification showed higher than predicted use, the team discovered outdoor lighting left on all night was using 20 percent of the project’s electricity. A vending machine and an old, inefficient commercial refrigerator that the school received as a donation were also troublesome. These demands have since been eliminated, but meanwhile, use data from the utility isn’t consistent with the school’s measurement and verification system. “Trying to close the loop between predicted performance and actual performance is a huge, complex problem,” and the overarching lesson of the project, says Shell. The team is looking for funding to continue research on unregulated loads, and will continue pursuing net-zero electricity by eliminating hidden uses and adding more PV capacity if necessary.
“We have to find a way to stick with our buildings longer and do these kinds of forensics if we want to truly understand building performance,” concludes Shell.
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