“There is not a single urban office building in the United States that is truly designed for today’s environment, much less for tomorrow’s, so we set out to build one: the greenest urban office building in the world.”
– Denis Hayes, President & CEO, the Bullitt Foundation, Seattle, WA
If this is the condition of USA then imagine where we the Indians stand in terms of creating high-performance green buildings. Today on our blog we would be exploring the curious case of the Bullitt Center and what we can learn from it.
The Bullitt Center is a work-in-progress, an experiment whose results are just beginning to emerge. Unless it informs, inspires and propagates other super high-performance buildings, the experiment will have been a failure. This report is intended to inform discussions regarding the design, construction, and operation of truly sustainable 21st Century buildings.
The Bullitt Center is owned and operated by the Bullitt Foundation, a sixty-year-old Seattle Philanthropy that seeks to make the Pacific Northwest a global model for sustainable, resilient prosperity. Its mission is to safeguard the natural environment by promoting responsible human activities and sustainable communities in the Pacific Northwest.
In its early years, the Foundation supported parks and open spaces. Later,
its focus was on the preservation of natural landscapes and wildlife habitat. The
Bullitt Foundation now supports a balance of efforts to nurture the health and sustainability of both natural and built environments. It envisions a future that safeguards the vitality of natural ecosystems while accommodating a sustainable human population in healthy, vibrant, equitable, and prosperous communities.
The Bullitt Center wasn’t built to house the Foundation and its six employees, who have operated effectively for decades out of the converted carriage house of the Stimson-Bullitt mansion in Seattle’s First Hill neighborhood. The Board of the Bullitt Foundation made the bold decision to dedicate a major portion of its endowment to create this model for 21st Century sustainability. It is a physical demonstration of the foundation’s commitment to urban ecology, the idea that cities must ultimately address their resource flows locally and sustainably in order to sustain the wild places from which the majority of our resources are drawn.
The Bullitt Center is a manifestation of the vision of Denis Hayes, President, and CEO of the Bullitt Foundation. Denis has been a leading advocate for the global transition from a fossil-fueled economy to a sustainable system based on energy efficiency and renewable energy sources. He was selected by President Jimmy Carter to be the first director of the Solar Energy Research Institute (SERI), now the National Renewable Energy Laboratory (NREL), where he led the early efforts to move the US towards a renewable energy future. He was among the early voices to warn of the existential threat of global climate change caused by the burning of fossil fuels. In his 1977 book, Rays of Hope, Denis outlined a roadmap for the transition to a post-petroleum world based on energy efficiency and renewable energy sources.
But why did Denis and the Bullitt Foundation choose to develop the world’s greenest building? Emissions from cars and power plants are generally the focus of carbon-cutting efforts, but of the US contribution to global greenhouse emissions, nearly 48% can be directly attributed to buildings. Buildings are the conduits through which the majority of electricity (75%) in this country flows. Most of this energy is produced by combusting coal (37%) and natural gas (30%). Reducing atmospheric greenhouse gas emissions in this century will require both significant performance gains in our stock of existing buildings, and the design, construction, and operation of super high-performance new buildings.
While energy efficiency and renewable energy were central to the vision for this building, Denis believed it was imperative to raise the bar exceptionally high for this building and to address all of the building’s resource flows and environmental impacts. He wanted to challenge the notion of buildings as disposable commodities, instruments for speculative investment with an effective lifespan measured in decades rather than centuries. And while he chose to create a new building rather than renovate an existing building, he imagined that the lessons learned from the design, construction, and operation of this building will inform both new and existing buildings.
Buildings are the most widespread and durable artifacts of human society. They exert a tremendous influence on our lives and on the health of the biosphere for decades after their creation. Most contemporary office buildings are developed as commodities with an imperative for quick returns on their investment. The Bullitt Center is designed and built for the long-term. It will operate largely on available site resources and will pay for energy embodied in its materials and construction through carbon offsets; it will provide ecosystem services by restoring the natural hydrology of the site and return nutrients to the land; and it will provide a healthy environment to support the activities of the people who visit and work in the building for the next 250 years.
The US Green Building Council has successfully advanced LEED as the industry standard in voluntary green building certification. It has advanced the conversation about high-performance buildings well beyond regulatory codes, to voluntary adoption of much higher standards for buildings. But there are shortcomings to LEED as a mechanism to advance the super high-performance buildings needed to address the challenges of the 21st century. Among these, it is a prescriptive and a predictive standard. If a project team accumulates the requisite number of points during the design and construction process, employing both prescribed features and predicting high energy performance, the building earns its certification along with a plaque that can be displayed on its first day of operation. Unfortunately, the correlation between high levels of LEED certification (gold and platinum) and actual energy performance has not been consistently demonstrated.
The Bullitt Foundation chose to pursue the more rigorous Living Building Challenge™ (LBC) because it is performance-based. In selecting the LBC for green certification of the Bullitt Center, Denis Hayes said: “we no longer have time for good intentions, to check-off boxes that say we’ve done this and done that, but result in a building that doesn’t perform as it was designed to perform.” Under the LBC, the building must perform as designed and meet all the criteria for energy, water, materials, as well as criteria for the site, health, equity, and beauty, during a full year of operation before it can obtain Living Building certification.
NATURAL VENTILATION AND PASSIVE COOLING
The Bullitt Center is a fresh air building. When CO2 sensors detect the need for fresh air, the windows open. If it is too cold or too hot outside, the windows remain closed and the ventilation system provides 100% outside air, tempered during the heating season by energy recovered from the exhaust air leaving the building.
The natural ventilation system provides fresh air but is designed primarily as a passive cooling system. This system displaces approximately 750 hours of annual cooling that would otherwise be needed without operable windows. Motorized actuators open the windows at night, during the summer, to flush the building with cool air to keep the building from overheating the following afternoon. Night-flush cooling typically lowers the slab temperatures 3oF to 5oF, allowing this mass to absorb more unwanted heat on warm summer afternoons.
HEATING & COOLING
Heating starts with internal gains from people, lights and equipment. On cool but sunny days, the windows let in free solar heating. The building envelope is designed to keep the heat in and the cold out. Under typical occupied conditions, supplemental heating isn’t needed until outdoor temperatures drop below about 46oF, the building’s operational balance point temperature. When this happens, the building’s ground source heat pump system kicks-in to produce hot water that is circulated throughout the building and delivered as radiant warmth through the building’s concrete floor slabs.
When cooling is necessary, the windows automatically open to provide cool, outdoor air. As the day warms and outside air no longer effectively cools the building, the windows close and the building’s concrete floors and hard surfaces, cooled by night-flush ventilation the previous evening, absorb excess heat to maintain indoor comfort. If the cooling capacity of the building’s mass is exhausted, cool water is cycled through the floors, drawing in excess indoor heat and transferring it, via the ground source heat pumps, to the earth beneath the building.
These heating and cooling systems are powered by electricity produced by the building’s photovoltaic (“PV”) system, or purchased from Seattle City Light with credits from surplus PV production during the summer months. (Under the rules of the Living Building Challenge combustion can’t be used for heating and cooling.)
BUILDING CONTROL SYSTEM
The direct digital control (DDC) of this building is driven by a KMC control system. This system monitor, logs and controls the building’s mechanical heating and cooling systems, the supply and wastewater systems, the air supply and exhaust systems, and sump pumps. This system also monitors, collects and logs data from the weather station and indoor sensors, water meters, pump flows, thermal energy, fans, and window operations.
What can we all learn from this?
Well, the crux of everything here is saving tonnes of money, and at the same time, the building is also helping protect the environment. In India, we seriously need to think on these lines. Reason being, our pollution is completely out of control. Every year big office buildings create tonnes of carbon and other pollution. Add to it the cost of running a building in India is pretty high. If you have read the case study excerpt above you would notice that everything in the Bullitt Center is designed to save money and be efficient. Companies In India really need to work on those lines now.
Source: The Bullit Foundation Case Study.