The American Institute of Architects (AIA) and the Committee on the Environment (COTE) have named 10 of the most sustainable architecture and design projects in the United States (US).
Each recipient of the 2017 COTE Top Ten awards had to submit post-occupancy data and sustainability narratives for their projects across 10 areas, including community, resources, water and energy. The winners were chosen for their proven ESD measures rather than their predicted performance.
We explore the success stories of five of the winners, all education projects setting new standards in the green building arena.
Chatham University Eden Hall Campus by Mithun, Pennsylvania
The project’s goal was “audacious”: to create the world’s first net-positive campus. Home to the institution’s Falk School of Sustainability, Eden Hall has proven that it generates more energy than it uses; produces food; is a water resource; recycles nutrients; and supports habitat and healthy soils.
The 388-acre campus features linked buildings, landscapes and infrastructure that support an active and experiential research environment. A local ‘low-impact’ material palette was selected for its durability, low maintenance and low environmental impact. Some innovations in the materials aisle include rainscreen cladding by TAKTL, a local business that developed a low embodied energy method for manufacturing the durable exterior panels. The design team also worked with PPG to specify a cost-effective, double-glazed product that out-performs triple glazed options.
Altogether, 1,017 metric tons of CO2 were released during the building’s construction, while 75 percent of construction waste was diverted from the landfill.
Discovery Elementary School by VMDO Architects, Virginia
As the largest zero-energy school in the US, Discovery Elementary School’s main challenge was to integrate a 98,000-square-foot building into a residential neighbourhood in Arlington, Virginia, while keeping its entire PV array on the roof. It is the first project to add a significant amount of new school construction in the country’s smallest county, and in a suburb hostile to urbanisation.
According to the AIA, these issues were resolved by terracing the mass into a south-facing hill. This allowed the project to meet local goals of scale, community goals of the preservation of flat, open recreation space, and global goals for ideal orientation for solar generation.
“Two important design process criteria were paramount: challenge the tendency of low expectations, and focus on children first,” the architects say. “The resulting primary design goal was to provide a joyful and engaging environment for learning – a place students couldn’t wait to get to in the morning and didn’t want to leave in the afternoon.
“The secondary goal was to design a building that would not just use less resources, but make a regenerative contribution to the well-being of its occupants, site and the world at large—specifically regarding the crisis of climate change.”
Discovery Elementary School’s actual annual consumed energy use intensity (EUI) is 16.2 kBtu/sq ft. Its actual annual net-carbon emissions are -0.29 lb/sq ft.
Following the success of the project, Arlington Public Schools are now asking for net-zero energy for all new schools. The US Department of Energy has also launched a Net Zero Accelerator program at the school to demonstrate that zero-energy schools can be constructed with today’s technologies at the cost of a conventional code-compliant school.
Bristol Community College John J. Sbrega Health and Science Building by Sasaki, Massachusetts
By now you should have guessed the running theme of net-zero energy across the AIA’s list of sustainable buildings. Bristol Community College is another project that sets a new standard, as the first zero-net academic science building in the Northeast. The 50,000-square-foot building sought to replace outdated labs with hands-on learning environments, such as labs, clinics, and ‘soft spaces’ for science and health science students.
The college had launched a power purchase agreement after its budget-setting feasibility study, building a 3.2-Megawatt solar array over its parking lot. However, this prompted a reassessment of its original ‘high-performance design’, which the team admits would not have kept pace with the college’s climate commitment. So, the goal was changed: to deliver a net-zero energy building without increasing the project budget. This was ultimately achieved. According to the team’s statement:
“In the ‘high-performance’ design, energy demand was driven largely by 18 fume hoods that exhaust 100 percent outside air. Switching to filtration fume hoods and air-quality monitoring unlocked a series of strategies that reduce the EUI by roughly 80 percent, including:
- 33-67 percent reduction in air changes
- Enthalpy wheel heat recovery
- Decoupling cooling/heating from ventilation
- Using fan coil units for local control
- 67 percent reduction in airflow
- High-performance envelope
- Expansion of interior temperature range to 70-76 degrees
- Natural ventilation
- 22 percent window-to-wall ratio
- Self-shading and 40 percent reduction in LPD
“For heating and hot water, the design integrates a dual-source heat pump and a solar-powered hot water system. Together with the solar arrays (site and roof), carbon-based energy sources have been eliminated.”
Milken Institute School of Public Health by Payette & Ayers Saint Gross, Washington, DC
This new LEED Platinum building at George Washington University is designed around the core values of public health: movement, air and light, connection to place, greenery, social interaction, and community engagement. Its research offices, classrooms and study areas are clustered around an array of multi-floor voice spaces that open the building’s dense core to daylight and views.
The project’s central challenge was accommodating the program on an awkward brownfield site while maintaining occupants’ connections with daylight, air and views.
“To achieve this, the design team extensively manipulated the building section. While the required program would have fit on six above-grade floors, the floor-to-floor height was squeezed to 12 feet and a seventh level was inserted within the allowable zoning envelope instead,” the AIA notes.
“This single move, only made possible through the optimisation and integration of the building’s structural and mechanical systems, was the genesis of an unconventional sky-lit atrium, in which classrooms and study areas overlook the city through an open latticework of floor openings, inviting exploration and discovery.
“An open stairway at the building’s center connects all eight occupied floors, promoting health and wellness by encouraging building occupants to forgo use of the elevators, which are screened from view.”
Materials were selected to reduce product-cycle environment impacts and optimise occupant health. The building’s vertically oriented terracotta paneled façade is one of the first of such applications in the US. Pre-assembled on a unitised curtain wall system to minimise on-site installation times, the system prevents pressure-driven moisture from entering the building. This in turn minimises the risk of corrosion and of mildew developing on the metal support system.
Eighty-five percent of construction waste (by weight) was diverted from landfill, while 20 percent of materials (by cost) from the original buildings were reused.
R.W. Kern Center by Bruner/Cott & Associates, Massachusetts
Designed as the gateway to Hampshire College’s Amherst campus, the R.W. Kern Center is a 17,000-square-foot, self-sustaining, multi-purpose facility. It generates its own energy, captures its own water, and processes its own waste.
One of the project’s major challenges was the cold climate, but the net-zero building features energy initiatives that mitigate the temperature and humidity fluctuations typical of New England: passive solar orientation, robust insulation, an air-tight envelope, exterior shades and triple-glazed windows. Strategic placements of operable window openings take advantage of daylight harvesting, while maintaining a 30 percent window-to-wall ratio.
“An inverter-driven heat pump system provides heating and cooling to the spaces, separate from the heat recovery ventilation system. By reducing the building’s design energy use, a rooftop solar array can generate more than enough energy on an annual basis,” the team adds.
Meanwhile, the cellulose-filled double stud cavity wall and roof achieve assembly values of R-40 and R-60, respectively.
Not only is the building Living Building Challenge certified, it also seeks to educate. Exposed electrical conduit, ductwork and piping showcase the active and passive systems of the net-zero building, in conjunction with a digital dashboard prominently displayed in the central commons and café spaces.
Source: American Institute of Architects