Arlington to Debut Net-Zero Energy Elementary School

ARLINGTON, Va. — Measure the soon-to-be-completed Discovery Elementary School in Arlington against nearly any other school in the region, and the differences will quickly become apparent. Where a traditional school would likely feature energy-hogging boiler and chiller systems and a veritable fleet of florescent lighting, the $35 million Discovery Elementary School has chosen another approach for its debut in August 2015. Instead, the facility will rely on a number of energy-efficient systems projected to earn it net-zero energy status.
Discovery Elementary School is expected to become the first net-zero energy school on the East Coast and is one of a series of school projects aimed at transforming 21st century education in Arlington County. The project’s primary objective is to set a new standard for sustainability, efficiency, flexibility and learning environment design, according to project architect VMDO Architects of Charlottesville, Va.
The two-story school building will encompass 98,000 square feet and include approximately 45 classroom spaces. It will accommodate up to 630, pre-kindergarten through fifth-grade students. Because the new school will also share a 25-acre site with the existing Williamsburg Middle School, according to VMDO, considerations for site footprint, solar orientation, building construction and energy use were given top priority.
The school will glean its heating and cooling from a 150-geothermal well-field, while a solar array will cover almost every square inch of available roof space. VMDO Associate Wyck Knox, who has worked extensively on the project, said these sustainable systems will result in an Energy Use Intensity (EUI) of just 23. Meanwhile, traditional elementary schools in Arlington have an average EUI of 68, and the national average is 70. This ultra-low EUI makes on-site photovoltaic energy generation possible within a traditional school budget.
“A typical school of this size would have a first-year energy cost of $124,000,” Knox said. “Our school is projected to have a first-year energy cost of $72,000. Over 20 years, the average school is going to cost $3.3 million in energy bills; this school will cost $1.9 million.”
The integration of green systems and materials will also require less effort from maintenance staff, according to Knox. “There is no boiler or chiller to maintain, just a series of residential size heat pump units floor mounted inside the building,” he said. He added that these smaller pump units can generally be serviced by a wider set of people, making it easier for the school to hire qualified maintenance staff.
The use of LED lighting also allowed the VMDO team to ease maintenance expectations and streamline building automation. “Wherever possible, we tried to simplify the building, so there are no complicated lighting controls for example,” Knox added. “We can get the watt per square footage down so low with LED lighting that we don’t need to try to save money through automatic dimming. There are less systems to break, less things to maintain, less things to not be scheduled properly.”
SIGAL Construction Corporation of Arlington was awarded the construction contract for Discovery Elementary School and expects to complete the structure by fall 2015. According to SIGAL Vice President Michael Shevitz, the firm has a wealth of experience in green construction, but this project presented an important first. “We’ve built solar systems and geothermal fields, but this is our first time building an Insulated Concrete Form (ICF) wall system,” Shevitz said.
Rather than using concrete forms that are then removed after the wall has set, ICF formwork is actually part of the permanent installation, according to Shevitz. The formwork is made of a rigid insulation that gives the walls an extremely high R-value and an incredible amount of thermal mass. As such, the amount of time it takes for energy to move the school walls will be much longer than traditional construction. Shevitz said this aspect in particular sets the project apart from most construction in the area. “I think it exciting for everybody to be a part of something that’s innovative,” he added.
Building on the theme of innovation, the VMDO team also looked for opportunities to use light and energy in creative and educational ways. A whimsical spiral slide connects the school’s first and second floors, and an educational rooftop solar lab is linked to the school’s energy dashboard for use in curriculum. An oculus located in a covered walkway — designed partially to add more roof space for the photovoltaic array — will even help students learn about the solar calendar and coordinate with an inlaid stone pattern on the school plaza.