“We like big, open spaces that aren’t constrained by the highway department.” That’s how Adam Tibbs describes the pre-engineered buildings produced by Project Frog. Because prefabricated systems are assembled in a factory in three-dimensional modules, “your dimensions are constrained by shipping. You lose a lot of flexibility that parts systems allow.” Project Frog instead produces giant jigsaw puzzles, flat-packing structural-steel panels and shipping them to a construction site. Since its launch in April 2006, it has turned approximately 20 kits of parts into operational projects.
Photo © Robert Benson Photography
The two-year-old Center for Science and Global Citizenship at the Watkinson School in Hartford, Connecticut, is one of them. Also known as the Solarium, the building is a venue for secondary level lectures, seminars, and laboratory work dedicated to interdisciplinary science and global studies. The 3,500-square-foot facility comprises three classrooms linked by a central lobby; each room occupies a taller canted volume that accents the building like a mod turret. The exterior is clad in reclaimed redwood.
To embody lessons of ecological responsibility, the Solarium is energy-neutral. The coeducational school’s headmaster John Bracker, “knew he needed a building that would catalyze the culture on campus around issues of global citizenship,” says Project Frog’s vice president of program development Marijke Smit.
While the pre-engineered system is geared toward high performance, Tibbs, who is president of Project Frog, says that the San Francisco–based company hits those marks with help. “There’s still a lot of work for the architect to perform, from working with the client to making sure the interior programming makes sense and that the specs are appropriate for it,” he says. In this case the Harford office of JCJ Architecture joined the Frog–Watkinson team.
While JCJ provided intimate understanding of code criteria and weather conditions for the Solarium, Project Frog supplied the architectural tools and technical assistance needed to, in Smit’s words, “formulate the design parameters and develop the building permit set for the project.” In particular, working with energy consultant Loisos + Ubbelohde, Frog defined the criteria for net-zero energy performance—finding the right balance of solar heat gain, daylighting, energy consumption, thermal comfort, and photovoltaic production. “Predictive modeling enabled the team to run multi-dimensional analysis that not only anticipated building energy usage, but also helped optimize materials like insulation, shading, and glazing,” Smit adds.
“We oriented the Solarium due south, because the school is occupied most regularly during the cooler times of the year: It’s more beneficial to absorb the heat gain in winter,” Tibbs says. Overhangs and sunshades mitigate glare, and a three-well ground source heat pump kicks into service during the few times when active heating or cooling is required. (The walls and roof contain R-19 and R-33 insulation, with additional material at the foundation.)
The building’s emphasis on solar gain seemingly worked against its canted rooftop form, with its PVs facing north. Tibbs says “the [predictive model] weighed the energy savings of southward orientation against the loss of energy production. Simultaneously we’re running a cost-benefit analysis, so that we stop investing in energy efficiency prior to the point of diminishing returns.” The calculators determined that a 60-panel PV array marked the break-even point between solar benefits and setbacks.
The predictions’ outcomes are now being monitored on Web-based energy dashboards, that differentiate the energy consumption of lighting, plug loads, and mechanicals. It meters PV generation, and records the temperature of the water in the ground source heat pump. “We also track thermal comfort by measuring temperature and humidity from classroom to classroom via several sensors located throughout the building,” Smit adds. In addition to providing students and teachers with this minute-by-minute learning tool, Project Frog equipped Watkinson faculty with an illustrated guide detailing the specifications and performance of every building feature, from those sensors down to the recycled carpet. (Some of those floor tiles are replaced by clear panels that reveal the building guts in the floor plenum.)
Both the Watkinson family and Project Frog are learning from the experience. The Solarium was the company’s first energy-neutral building platform and the first project armed with a web-based dashboard. Smit says, “Because John and his staff have been such cooperative, ongoing partners, we have been able to incorporate many of our lessons at Watkinson into subsequent product iterations for other projects.”