Putting together a list of the top ten green buildings in the US is a difficult task. Everyone’s definition of “green” is colored by what aspects of a building they think affect our environment the greatest. Some say building green means saving energy, others think it means disturbing the Earth as little as possible. Knowing that we cannot please everyone, and with a focus on net-zero energy, here is a list of great US projects that have been recognized as “green” in the last two years.
1. Bristol Community College John J. Sbrega Health and Science Building
Location: Fall River, Massachusetts
Contractor: Bond Brothers
Located on the campus of Bristol Community College, this 50,000-square foot Health and Science Building is the first net-zero energy academic science building in the Northeast. Its program accommodates instructional labs and support space for field biology, biotech, microbiology, and chemistry; nursing simulation labs; clinical laboratory science and medical assisting labs; dental hygiene labs; and a teaching clinic.
By using passive strategies and harvesting renewable solar power, the building is able to reach its net-zero goal. Here are some of the strategies the project employed in order to reduce energy use in the tough New England climate:
filtration fume hoods/air-quality monitoring in laboratories
67 per cent reduction in outside air infiltration
high-performance building envelope
expansion of the interior temperature range
natural ventilation: operable windows, both automatic and manual
22 per cent window-to-wall ratio: greater proportion of opaque wall to glass
self-shading: deep roof overhangs, fritted glass, shading devices
40 per cent reduction in lighting power density (LPD): half the number of fixtures typically found in laboratories, and use of LEDs
Taking a holistic approach to the design and construction of the Sbrega Health and Science Building, the team developed innovative ways to eliminate the use of fossil fuels, increase efficiency, and dramatically reduce energy demand.
2. Brock Environmental Center
Location: Virginia Beach, Virginia
Contractor: Hourigan Construction
The Brock Environmental Center is designed to express the Chesapeake Bay Foundation’s mission of collaboration to protect one of the nation’s most valuable and threatened natural resources. The Foundation aspired to true sustainability in the building’s design and operation. The Center surpasses LEED, achieving zero-net-CO? emissions, zero waste, and Living Building Challenge certification from the International Living Future Institute.
Carefully placed and sized windows allow for heat gain when desired and cooling when needed in the heat of the day. A sheltered porch along the south side of the building allows for daylighting without heat gain. The Center also features a “dogtrot”—an open air pass-through that creates a comfortable micro-climate by promoting airflow to reduce horizontal stratification.
A variable refrigerant flow (VRF) HVAC system, with dedicated outside air ventilation, uses ground-source wells to improve heating and cooling efficiency. The Center uses two wind turbines and a 45-kW photovoltaic array to provide 80 per cent more power than the building needs.
3. Discovery Elementary School
Location: Arlington, Virginia
Discovery Elementary School is the largest net-zero energy school in the US. Terraced into a south-facing hill and nestled in a residential neighborhood, the project preserved flat, open spaces for recreation and was able to provide the perfect orientation for the roof-mounted solar panels. Discovery School offers a positive example of a solution to climate change, and encourages students to be creative participants in those solutions along the way.
Due to local limits on the size of the solar array that could be installed, it became imperative that energy use be reduced drastically. Passive design strategies included high thermal mass through insulating concrete form (ICF) construction, a terraced building section that brought light deep into the building while maximizing rooftop space for PV, and a focus on air-sealing–which produced a building that tested at .12 cfm/sq ft for air infiltration, which is 80 percent better than code.
Light is celebrated throughout the school, from colorful sunshades, to a solar lab connected to a custom designed dashboard, to a solar calendar in the front entry plaza.
The mechanical, geothermal, electrical, and control systems bid at 28 per cent of the overall construction price, which meant that the required high-performance systems were provided at the same price point as for standard construction. The building was originally budgeted for LEED Silver only, and it was able to achieve net-zero with no increase to the original budget.
4. R.W. Kern Center
Location: Amherst, Massachusetts
Contractor: Wright Builders
Hampshire College’s R.W. Kern Center is a 17,000 sq ft multi-purpose facility that was designed to meet the Living Building Challenge. The Kern Center includes classrooms, offices, a café, and gallery space. The building is truly self-sustaining—it is generating its own energy, capturing its own water, and processing its own waste.
Due to the climate in the northeast, the building’s envelope was specially designed to resist the harsh weather. Strategies include passive solar orientation, robust insulation, an air-tight envelope, exterior shades, and triple-glazed windows, all of which help mitigate swings in temperature and humidity. Building energy use was reduced to such a degree that a rooftop solar array easily produces enough power to make the project net-zero energy.
The Kern is a welcome center for the campus, and the college is taking advantage of the opportunity to provide education on green building and building systems. The exposed electrical conduit, ductwork, and piping show the active and passive systems that help create a net-zero energy building. In addition, there is a digital dashboard prominently displayed in the central commons and café space. It provides information on the building’s systems and performance to campus visitors via website and an on-site brochure.
The Kern Center was designed to work within the carrying capacity of its site, “living within its means” in terms of available resources. It provides its own energy and water, and takes responsibility for its own waste, water runoff, and environmental impact. Surprisingly, the Kern Center has no utility bills.
5. Center for Sustainable Landscapes
Location: Pittsburgh, Pennsylvania
Contractor: Turner Construction
The Center for Sustainable Landscapes is a 24,350-square-foot education, research and administration facility at Phipps Conservatory and Botanical Gardens, a public garden attraction in Pittsburgh. The facility is the first in the world to meet all four of the world’s highest green construction standards: The Living Building Challenge, awarded in March 2015; WELL Building Platinum, awarded in October 2014; Four-Stars Sustainable Sites Initiative (SITES) certification for landscapes, awarded in November 2013; and LEED Platinum, awarded in August 2013.
The building’s purpose is to educate the public about the integration of the built and natural environments and to increase knowledge of sustainable building strategies and systems. It focuses on passive strategies to reduce energy use and improve the connection to the natural world. Operable windows and access to views of nature from virtually everywhere in the building help with occupant comfort and well-being. With occupancy sensors, daylight dimming controls, and LED task lighting where needed, only the necessary amount of artificial light is provided.
Using photovoltaics and geothermal energy, the building has been able to achieve net-zero energy use, and has increased its surplus of energy each year it started operating. Having a net-zero building powered by onsite renewable energy eliminates fossil fuel use and the greenhouse gasses associated with carbon-intensive energy production.
6. The Dixon Water Foundation Josey Pavilion
Location: Decatur, Texas
Contractor: Lincoln Builders of Texas
The Josey Pavilion is an education and meeting center for the Dixon Water Foundation, whose mission is to promote healthy watersheds through sustainable land management. The center facilitates a deeper understanding of grazing livestock as well as the built environment can work to do more good than harm to the natural environment.
The main energy-saving strategy was the replacement of active mechanical systems with passive measures. Additionally, low-energy-using selections for hot water generation, ceiling fans, lighting, plugs, equipment, and appliances allowed the project to save more energy. These selections included point-of-use water heaters, LED light fixtures, and efficient appliances.
A constructed wetland system, which includes many pumps and filters, provides the largest energy draw. This system recycles all the water used at the project, and returns it to the land. All water that falls on the site is used and cleaned naturally. The system parallels how rain is collected in a watershed, used by plants and people, processed by wetlands—nature’s kidneys — and returned to aquifers belowground.
The addition of a 4-kW photovoltaic array, along with careful monitoring of the site’s energy use, allows the project to generate 150 per cent of the power used on site.
7. West Branch of the Berkeley Public Library
Location: Berkeley, California
Contractor: Kitchel CEM
The City of Berkeley sought to update its undersized West Branch Library, and decided the best way to do this was to build a new building. Amenities include a book drop-off, bike parking, and places to meet or relax that are included within a large frame that reinforces the street front and creates a sheltering alcove leading to the front entrance.
The use of extensive daylighting and natural ventilation allow the building to be used even during a power outage. Efficient windows, skylights, and glass placement allow the use of natural light and reduce the need for heating and cooling. The building is 76 per cent more efficient than the AIA 2030 energy performance baseline.
The project uses both photovoltaic power generation and solar water heating to offset the energy used. The library was net positive energy in its first year of operation. With energy use reduction and the use of renewable energy, the building contributes little to peak energy demands on the utility.
8. The Bullitt Center
Location: Seattle, Washington
Contractor: Schuchart Construction
The Bullitt Center was designed as a prototype for an urban high-performance office building. The hope was that it could be replicated and would have virtually no environmental footprint. The building is self-sustaining, and it is designed as a 'living' organism using only as much water and energy as it takes in.
All of the building’s power comes from its rooftop photovoltaic array, which is tilted slightly to allow it to achieve the maximum solar exposure. What is more, the array is mounted on a rack system that extends beyond the footprint of the building, allowing for more PV panels, and providing an overhang to shade the upper floors. A ground source heat pump system provides radiant heating and cooling. Efficient LED light fixtures reduce the amount of power needed to light work spaces. Daylighting is integrated into all floors of the building.
One of the unique features of the building is its ‘energy budget’ lease incentive that rewards its tenants for energy efficiency. Each tenant is allowed so much power for plug loads and processes, and is rewarded for savings.
The Bullitt Center meets the ultimate goal of the 2030 Challenge now—demonstrating this goal is feasible, even in a mid-rise urban office building in a cloud-covered city.
9. Exploratorium at Pier 15
Location: San Francisco, California
Contractor: Nibbi Brothers General Contractors
The Exploratorium is a hands-on science museum that focuses on natural phenomena. It is built on a rehabilitated site at the historic Pier 15 on San Francisco’s downtown waterfront. The building offers a theater, more than a dozen classrooms, labs, and teacher training rooms, wood and metal workshops, two retail stores, offices, and a large outdoor plaza. Surprisingly, it offers no parking for its more than 1,000,000 visitors a year.
The center uses bay water and heat pumps/exchangers for its radiant heating and cooling system. The building uses 55 per cent less energy than a comparable benchmark building, without the use of fossil fuels, except for cooking.
An 800-foot-long roof allows room for a photovoltaic system that offsets all of the center’s electricity use. Some exhibits had to be redesigned to reduce the energy draw to meet this goal. More than 110 power meters monitor electric loads, enabling staff to continuously improve building operation. A live display in the lobby communicates the status of the net-zero energy goal to the building’s more than half million visitors, as well as the 12 million visitors online. The building did not reach its net-zero goal the first year in operation, but changes have been made to achieve the goal in the future.
10. J. Craig Venter Institute
Location: La Jolla, California
Contractor: McCarthy Building Companies
The design team for this project was tasked with coming up with a net-zero laboratory building for their client’s new West Coast research institute. In the end, they came up with a single-story laboratory wing and a three-story office/administrative wing, surrounding a central courtyard, all sitting above a below-grade parking structure for 112 cars. It was designed to achieve LEED-Platinum certification and a net-zero energy footprint, making it the first such biological laboratory in the country.
The center utilizes a 50,000-gallon thermal energy storage (TES) system as the primary air-conditioning driver. Cooling towers cool the TES at night, allowing the building to be conditioned most days without electrical chillers. As cooling is drawn out of the TES, it is replaced with warm water that can be used at night for heating purposes. Reject heating water is captured from a separate water loop feeding a water-cooled, low temperature (-80F) freezer farm.
A large photovoltaic array is sized to over-produce electricity, allowing the center to feed power back into the grid, and thus making the net-zero energy goal possible.