By Patricia Kirk
A new school in Palm Bay, FL, proves the adage "need is the mother of invention."
A bare-bones budget drove Spacecoast Architects P.A. of Indialantic, FL, to deliver a sustainable building full of construction and operational cost efficiencies.
Opening in 2005, the first school built with the Odyssey design prototype cost $70 per square foot, compared to typical school construction at $150 per square foot, and uses 30 percent as much energy to operate as a conventional school building, including "plug-in loads."
The Odyssey design prototype incorporates principles of building orientation, daylighting, natural ventilation, advanced thermal envelope design, active and passive thermal storage, and demand management.
The measures have earned the school the Designed to Earn the ENERGY STAR® rating, an outreach effort of the Environmental Protection Agency (EPA) aimed at helping architects design buildings intended to achieve ENERGY STAR performance standards once the facilities are built and in operation. The overall ENERGY STAR program awards the ENERGY STAR label to buildings that meet the EPA's high-energy performance requirements so consumers can identify energy-efficient products, homes, and buildings.
Lead architect and Spacecoast President Lawrence Maxwell says that there is no choice but to economize in constructing and operating charter schools in Florida because the state does not fund charter school construction, which therefore must be financed. Charter schools provide opportunities to use alternative educational curriculum and teaching methods to meet the needs of exceptional or special needs children but receive less than half as much in state funding per student as traditional public schools in Florida.
The 47,000-square-foot Odyssey school serves 550 prekindergarten through eighth-grade students and houses 26 classrooms, a library, cafetorium, music and science rooms, and administrative offices.
This school design is so successful because high energy performance was programmed into the building's DNA rather than relying on expensive technologies. "Energy performance was achieved with natural, simplistic means using everything we know about how things work [energy-wise]," Maxwell says. The first step in sustainability, he says, is to reduce energy load; technology can then reduce it farther.
Exterior Efficiency
Designers started their quest for energy performance outside, with proper site orientation; a thermally efficient building envelope with an exterior insulation and finishing system on tilt-up concrete; use of light-colored, reflective metal roofing; and maximum levels of roof insulation.
Placing the insulation on the exterior wall protects the building from heat gain, Maxwell says, and offered the option to expose concrete walls on the interior. There, the building team painted walls in bright colors, saving money on interior finishings while giving indoor spaces an artsy feel. Instead of linoleum, stained concrete floors proved to be a superior alternative to vinyl, providing a more durable, attractive, easy-to-maintain flooring.
Windows on a long east-west axis maximize daylighting while minimizing the air-conditioning load. Classrooms have north-facing high "daylight" and low "vision" apertures, or windows, to capture light from the north, which is considered high-quality lighting because there is no direct solar gain or glare. The lower north-facing windows are 36 inches off the floor to a height of 7 feet.
The sloped ceilings in classrooms increase daylight penetration from the north and south and help balance the level of light distribution in classrooms. Ceilings start at 9 feet and slope up to 11 feet; at the rooms' midpoint ceilings shoot straight up 14 feet, where a row of clerestory windows facing north create a skylight effect. A light-color roof overhang shades and reflects indirect light through a row of 12-inch, clerestory, south-facing windows to maximize daylight while minimizing heat gain.
"Bouncing light off the roof deck strips heat out of long-wave radiation, creating a reverse greenhouse effect," explains Maxwell. "This way you bring in the visible light spectrum, but the heat doesn't pass through the window."
Roof overhangs, small apertures, and light shelves in appropriate places capture and bounce light up into classroom and office spaces, providing additional daylighting without glare on tabletops or computer screens. Shading devices were mounted above windows in south-facing offices, and a light shelf reflects and bounces light up on the ceiling, scattering it throughout the room. A similar strategy is used to light up computer corridors, where direct sunlight entering through small upper apertures is bounced off the ceiling to provide a high level of light without the glare.
The sloped ceilings improve sound acoustics because classroom floors and ceilings are not parallel surfaces. Varied surfaces give spaces tone and resonance yet allow absorption of sounds so rooms are neither dead nor overly lively and reverberant, notes Maxwell.
The design criteria minimized the building's impact on the site by placing the structure on an area previously disrupted by a pile of soil left from digging of a drainage canal many years earlier. Indigenious plants were used to landscape, and a 100-foot strip of existing vegetation was preserved around the school to provide a natural view and place to teach students about native plants and their habitat.
Climate Control
The HVAC design was the one thing the architect refused to modify to save first costs, as it is essential to controlling energy costs, attaining the desired high indoor air quality standards, and maintaining efficiency of systems. The high-ticket item is a digital, fully computerized AMES Energy Management System (EMS) that controls all mechanical and electrical systems, including HVAC and lighting, and offers individual temperature control in classrooms. The EMS also allows staff to monitor systems remotely from a computer terminal, notes Clif Runkel, the mechanical engineer for the project.
Outside air units maintain ventilation. These units cool the outside air down to 50 degrees F, dehumidifying the air before it enters the air-handling units. Variable speed frequency controllers match ventilation requirements with the actual building occupancy loads. The air-handling units have 90 percent filters, providing the school with hospital-grade air quality.
Odyssey's chilled-water cooling system includes a thermal storage system that produces ice at night during low electrical peak times and uses the ice to cool the school during the day, when power demand peaks. Runkel estimates that the cooling system saves $2,000 to $2,500 per month in electricity costs.
EPA Accolades
Spacecoast architects used 3-D ArchiCAD modeling to evaluate the effectiveness of key design strategies functioning together and to validate energy-saving design decisions. The Odyssey school easily qualified for the ENERGY STAR rating, earning 95 out of 100 possible points for energy performance. To qualify for the ENERGY STAR label, a building must earn at least 70 points.
A second Odyssey school, proposed for Orlando but still in design, has been prequalified for 100 out of 100 points. The design adds photovoltaic collectors on rooftops and an automated lighting control system that adjusts artificial lighting based on natural light levels present.
Maxwell, however, fully expects this building to perform in the negative net energy zone, producing more energy than needed and adding electricity back to the grid. He notes that with building energy use in the built school already less than 29 percent of a conventionally built school, the addition of renewable energy and conservation technologies is "icing on the cake."
Noting that this project demonstrates how to achieve sustainability using fundamental design principles, Maxwell concludes, "I have always felt that good architecture is not about style as much as substance. The truly exciting thing about good, sustainable design is that it strives to find the best the earth has to offer to elevate the human experience."
He adds, "It is not just about saving energy but more about preserving what is beautiful in this world, not taking more than you need, and designing spaces and ‘experiences' that elevate the spirit."
