The Bullitt Center in Seattle, Washington, is one of the most self-sufficient buildings on the planet. It is net zero energy and, after the water reuse system is approved by city authorities, net zero water. Net zero means that the building uses the same amount as it creates or generates – it is self-sufficient. In a series of posts here on GBE, we will look at what makes this building tick.
Solar Power
The Bullitt Center uses photovoltaic (PV) panels to generate electricity. Conventional wisdom would say that Seattle isn’t the sunniest of locations to set up a solar energy system, but it works. During the summer, when sunshine is abundant, the system sends its excess electricity out to the grid, helping the City keep up with increased demand. During the winter months, when it is overcast, the Center draws from the grid as needed. Over a year’s time, the amount of electricity generated by the PV system is above the amount used by the building and its occupants.
The solar panels, provided by SunPower, are some of the highest efficiency panels available in the world for commercial applications. 570 panels cover the distinctive mortar board roof structure that extends out over the edge of the building. The panels collectively generate approximately 230,000 KWH per year.
+ Efficiency
Tenants of the six-story, 50,000 square foot building are allotted an energy budget each month, depending on the size of the space they lease. Those tenants that stay within their budget are charged nothing for the electricity they use. This provides incentives for tenants to be energy-efficient. The building uses approximately 230,000 KWH per year, compared to a typical office building of the same size that uses 1,077,000 KWH.
The building uses daylighting, geothermal heating and cooling, operable windows, and other measures to increase its energy efficiency. The design team applied for special permission from the City of Seattle to increase the height of each floor of the building to allow for improved daylighting further into the core of the structure, reducing the need for heat-generating light fixtures. Geothermal and radiant floor heating and cooling are used to efficiently moderate temperatures within. The building management system (BMS) regulates the heating and cooling systems, and even controls the window shades and operable windows to optimize efficiency. The BMS acts as the “brain” for the entire building, controlling all processes, such as composting, water treatment, and ventilation.
= Net Zero
The combination of site-generated electricity and high energy efficiency means the Bullitt Center uses the same amount of energy as it produces. It has a net zero energy effect on the environment – the true definition of a sustainable building. The Center is seeking certification from the Living Building Challenge, which recognizes structures that go beyond “green” and take responsibility for their effects on the environment and take steps to reduce those effects and/or offset them.
Update
After one year of operation, the Bullitt Center used 147,000 KWH of electricity and generated 252,000 KWH. The project was 85% occupied during this time and tenants were extremely satisfied with the building and its greenness.
In an April 2014 press release, Denis Hayes, CEO of the Bullitt Foundation said, “After seeing how the Bullitt Center performed in its first year, I’m certain we will be net positive energy, not just net zero. If we can do this in cloudy Seattle, owners in other cities should be embarrassed if they don’t achieve zero net energy.”
Water
Rainwater Catchment System
Rainwater falling on the PV panel roof of the Bullitt Center flows through the panels and into a 56,000 gallon cistern, which is actually a room in the basement. The system supplies non-potable water for all of the toilets, hose spigots, and the irrigation system.
A treatment system to take rainwater to potable standards is provided in the building, but it has not been approved for use by the City yet. The system will send the rainwater through a series of filters, including an ultrafilter so fine it removes viruses, and an ultraviolet disinfection system. Until the treatment system is approved for use, the building gets its potable water from the city water system.
Composting Toilets and More
Foam flush toilets that use less than a cup of rainwater per flush are used in all bathrooms in the Center. A natural soap helps the waste slide to the basement, where the waste is stored in one of several composting units. Wood chips are added to the waste, and with the help of heated air circulated through the units, about 90 gallons of compost are produced per unit per year. Temperatures in the composters are kept at 135 to 165 F to ensure that pathogens and contaminants are eliminated.
The compost and a nutrient-rich leachate that is drained from the units is shipped to a nearby composting facility and will be combined with other materials to be used as a soil amendment.
Gray water, waste from the sinks and showers in the building, is distributed to a constructed wetland on the second floor roof, where the water is filtered by the soil and vegetation. Once it meets city standards, it goes to a planting strip where it eventually returns to the city’s aquifer.
Challenging the Status Quo
The Bullitt Center’s innovative plumbing and rainwater treatment systems have tested the boundaries of local building codes and jurisdictions. No project has been this advanced in its thinking. The City of Seattle has been working with the design team to provide assistance for other projects looking to use similar systems.
Advancements made through the project include a pilot program to help other projects looking for Living Building certification, the approval of the composting system, and continued work to approve the rainwater treatment system for use as potable water.
Healthy Green Materials
The Living Building Challenge requires projects to avoid as many of the chemicals and substances that are found on the Red List as possible. These substances have been recognized by government agencies, such as the US Environmental Protection Agency, the European Union Commission, and the State of California, as potentially harmful to human or animal life on Earth. Not all of the substances can be avoided, though, due to the lack of availability of materials that do not contain them.
The Bullitt Center team avoided over 360 known chemicals on this list. Some were easy to avoid, as alternatives were readily available. The team also worked with suppliers to create products that met their requirements, changing the way the products were made and making them available to others.
Most plumbing valves, even those made of brass and bronze, contain up to 7% lead. Lead free valves, with an allowable lead content of only 0.25%, were used in both the potable and non-potable water systems, including fire sprinklers.
Phthalates are commonly used in PVC and other plastic products. A high-performance water barrier company performed 6 months of research to develop a product that did not contain phthalates, just for the Bullitt Center project. The new product has now replaced the original version going forward.
Dioxins are a by-product of the manufacture, combustion, and disposal of products containing chlorine, most notably PVC products. Couplings for no-hub ductile iron pipe are commonly made with neoprene, which contains chlorine. The team worked with the manufacturer to special order couplings made of EPDM (ethylene propylene diene monomer) rubber.
The electrician was able to find electrical wire not coated in PVC that met code standards.
The fiberglass insulation in the project is held together by a plant-based polymer, not the usual one that contains formaldehyde.
Certified Wood
The Bullitt Center is a wood-framed structure. Because of its location and the importance of the timber industry in the Pacific Northwest, the project team decided this was the best choice for the project. 100% of the lumber in the building has been harvested from an Forest Stewardship Council (FSC) certified source. The project was also recognized as the only commercial project to receive the Forest Stewardship Council Project Certification, in recognition of responsible forest products use throughout the building.
Local Sourcing
Perhaps the greatest story about green materials and the Bullitt Center involves the curtain wall (window) system. Due to the high performance needs of the project, only one product could be used, and it was only manufactured in Europe. A Washington company partnered with the European manufacturer to gain the knowledge to manufacture and install the system in the US. The Washington company flew their employees over to find out how to make and install the system, and a licensing agreement was reached. Now this high performance system is available in the US for future projects to use.
The Bullitt Center team worked with contractors and suppliers to provide green materials throughout the building, some of which were not available before this project. The team changed the future of green building by asking questions and challenging the status quo.
Policy Changes
As we’ve seen in this series, the Bullitt Center project challenged many of the current building codes and concepts of how a building is built. Cooperation among competitors, installation of unapproved systems, and pushing the envelope of what is considered the “way things are done” have characterized the project from the beginning. The project has been successful in preparing the way for similar projects.
According to the media kit from the Bullitt Center Foundation: “The era of cheap abundant energy, plentiful fresh water, and localized impacts of human activities is over. Humans now affect every corner of the planet. Yet virtually no new buildings – even “green buildings” – are being built to function harmoniously in the conditions we know will prevail. The Bullitt Center is designed to still make sense 250 years from now. And it was built to ease barriers for projects yet to come. The first Prius cost more than the 10,000th. But before you can build the 10,000th of anything, you need to build the first.”
One of the biggest impacts of the Bullitt Center project is the development of the Living Building Pilot Program in the City of Seattle. This program will make the process of building future Living Buildings a bit easier. It allowed changes such as increasing the floor-to-floor height of building levels, allowing for more daylight to reach the inner sections of the building. The City will use these types of changes to revise the current building codes, therefore increasing the energy efficiency of all new buildings.
The Center team decided to provide bike-only parking on the site and developed a transportation plan for its occupants to reduce the use of single-occupant vehicles. This is the City’s first commercial building to take advantage of legislation focused on designated Urban Villages that are well served by public transportation.
The project team designed and built a fully functioning water treatment plant in the building. However, the system has yet to be approved by City and state officials. The team is actively working with these authorities to get this system approved so the Bullitt Center can be net zero water as well. It is not known when approval will be achieved. Meanwhile the building is hooked up to municipal water and waste until the treatment system can be used.
There also was no precedent for using a greywater reuse and composting system in a commercial setting. The project team worked with City, State, and county authorities to design a system and get it approved. This sets the stage for other projects to follow in their footsteps. It is good to see building teams and authorities working together to make a building more efficient.
The project team’s desire to design their project to be the most efficient building they could make, and their willingness to work with the local jurisdictions to make this happen, have led to the Bullitt Center. It is a showcase for what can be done when teams are willing to work together, and for what can come from a vision.
Previously posted on Green Building Elements in 2015.
Photo by Brad Kahn, through a Creative Commons License.
