School Could Become Largest Net-Zero Campus
IRVING, Texas — The Irving Independent School District broke ground on what will be the nation’s largest net-zero public school, according to reports.
The first of its kind in Texas, the Irving ISD’s Lady Bird Johnson Middle School is designed to produce as much energy as it uses, and at about 50 percent less than a similarly sized school.
Named after the wife of former U.S. President Lyndon B. Johnson, the $29 million, two-story middle school epitomizes the former First Lady’s commitment to conservation and environmental protection by using a 600-kilowatt rooftop solar array and 12 2.4-kw wind turbines to generate power. Any excess energy the 151,000-square-foot school produces will be sold back to a local electricity provider.
The zero-energy school will use a 530-well geothermal system, efficient lighting and water fixtures, and a rainwater harvesting setup that collects greywater for use in irrigation to drive down energy usage by an estimated 50 percent.
Adding design changes and components to achieve net zero increased building costs by about 15 percent — which was expected, says Scott Layne, Assistant Superintendent for Support Services.
“From the beginning, we clearly communicated with our board that to erect a building structure of this magnitude and efficiency meant costs between 15 and 20 percent over and above that of a typical middle school,” Layne says. “Within our base bid of $25 million, there was an estimated $2 million associated with infrastructure needs engineered to decrease energy consumption.”
“We will spend an estimated $3.2 million on the solar panels and wind turbines,” Layne added. “But without that initial $2 million in energy efficient infrastructure improvements, we wouldn’t be able to reach net-zero since the building load would be too high.”
The school district predicts a 12-15 year payback on construction costs.
IISD’s goal was two-pronged in building a zero-energy facility: First, to achieve a cost savings on utilities, and second, to reduce its environmental footprint while serving as a model of efficiency.
“We want to positively affect our environment by reducing our carbon footprint and utilizing renewable energies to dramatically decrease our annual utility costs,” says Layne. “We are fortunate indeed to be in a position to take this positive step now; many school districts nationwide are financially unable to do more than maintain existing systems. By making this concept a reality within the public school sector, we hope to lead the way for other districts over the course of time.”
When completed in the summer of 2011, the Lady Bird Johnson school will have to produce more than 800,000-kilowatt hours of electricity per year to be a net-zero facility.
The school’s 3,000 cylindrical module solar panels, manufactured by Solyndra, of Fremont, Calif., will produce most of that energy from direct, indirect and ambient sunlight, says Susan Smith, vice president of the architecture firm Corgan Associates, based in Dallas. The small commercial wind turbines, built by Skystream, will produce only a fraction of the energy needed to operate the building, Smith says. Convia Inc., of Buffalo Grove, Ill., will provide its energy management technology for the integrated control of lighting, plug loads, and HVAC/thermostat set points — an area that can account for as much as 93 percent of energy use in a school.
The middle school will include not only specialized components, like the wind turbines and the solar panels, but also many elements that are considered standard in building energy-efficient schools today. Lighting will incorporate occupancy and daylight harvesting sensors, the latter of which is meant to measure natural light coming in and balance that with powered lighting. Heavily insulated walls, high efficiency glazed windows, and an Energy Star-rated kitchen will reduce operating costs, while permeable paving will cut back on storm water runoff.
“What’s unusual about this project is that we have the typical increased daylighting and other components that we do on many of our sustainable projects, but this net-zero project also incorporates wind turbines, solar panels and a power management system that are not common on schools,” says Mike Parkos, senior project manager with Charter Builders of Dallas, the construction manager at-risk for the project.
“A major challenge is coordinating the intricate nature of the systems,” adds Aaron Scates, vice president of operations at Charter, which is a subsidiary of Balfour Beatty Construction.
“We’re creating renewable energy sources from wind and solar systems and we’re trying to lower the net power the building needs to operate by incorporating in the energy efficient design of the mechanical, electrical, and plumbing systems, along with a highly insulated building envelope,” says Scates.
The use of Building Information Modeling has alleviated some of that challenge.
“BIM is being utilized on this project to help coordinate the various elements of the entire building before the materials are fabricated,” says Scates. “Once the building has been ‘built’ in the model, we will look for opportunities to prefabricate elements of the school to help cut down on time spent on installation in the field.”
In addition to aiming for net-zero on the project, developers are hoping to achieve at least LEED Gold, possibly LEED Platinum. The two goals go largely hand-in-hand, Smith says.
“When the district started this project, their goal was a net-zero building. Their end goal really had nothing to do with LEED,” Smith says. “The way we have approached LEED on this project is by determining the district’s goals for sustainability and energy consumption first. Once those benchmarks were established, we better understood how LEED fit into the program.”
The net-zero goal and the LEED program worked collaboratively in that LEED further recognized what the district had already decided to do, says Smith. To achieve the last few points needed for LEED Platinum, the district will have to decide whether it wants to spend the extra money.
Lady Bird Johnson Middle School will incorporate a variety of monitoring technologies designed to both audit solar and wind energy production and to integrate renewable energy data into classroom curriculum.
“The school’s advanced monitoring system will benefit the district, allowing facility personnel to track energy performance and determine if something is underperforming,” says Smith. “This data will integrate meaningfully within the science curriculum. Additionally, we’ve designed learning areas within the school that feature monitors displaying real-time data.”
Assistant Superintendent Scott Layne sees the new middle school becoming a part of the science curriculum for students throughout the region.
“The board of trustees was very clear from the beginning that it didn’t want the project to be isolated to the sixth, seventh and eighth graders at that school, but rather integrated into the coursework for all of our students in the district,” Layne says.
The middle school’s interactive exhibits will make the building a field-trip destination, essentially, for the entire district. Developed much like a living lab, the school will house a large instructional omni room and four learning areas — or nodes — each of which teaches about a different technology: solar panels, wind turbines, geothermal system and water conservation. Currently, the district’s Teaching and Learning Division is developing K-12 curriculum that focuses on the new school, Layne says.
“Our desire is that people from all over the U.S. will visit us to gain a greater perspective of what this innovative school will mean to the future of education, the economy, and to the environment,” says Layne. “In the process, they will see how we in Irving ISD are redefining the 21st century model for learning spaces. We look at this recognition — having this net-zero school — as an achievement for the entire district, and we want to share that.”