The Innovative Initiatives to Meet the Living Building Challenge Energy Petal Requirements
The Chesapeake Bay Foundation Brock Environmental Center is striving to be Virginia’s first “net zero” facility. The Preconstruction phase of the project has been critical to meet the needs of the “Energy” Petal of the Living Building Challenge.
The Living Building Challenge is raising the bar of sustainability–providing a framework for improving the relationship between people and all aspects of the built environment. It consists of seven performance areas, or “Petals” – Materials, Site, Water, Energy, Health, Equity and Beauty.
We previously described how Hourigan Construction is helping this CBF project meet the requirements of the Materials Petal and the Site Petal. Next, we will explain the innovative initiatives that will help the facility meet the needs of the Energy Petal.
Intent of the Energy Petal
The Living Building Challenge “envisions a safe, reliable and decentralized power grid, founded on renewable energy.” The Energy Petal represents a new age of design in which the built environment relies solely on renewable forms of energy and operates in a pollution-free manner. It aims to eliminate wasteful expense of energy, resources and dollars to produce buildings that are extremely efficient without the crutch of combustion.
The majority of energy created today comes from combustible sources like coal, gas and oil that are highly unsustainable. The effects of these energy sources are becoming increasingly evident through climate change, a worrisome global trend.
Renewable energy sources contribute to Net Zero Energy of the Center
According to the Energy Petal specifications, one hundred percent of a project’s energy needs must be supplied by on-site renewable energy sources on a net annual basis. This means that the building must generate at least as much energy as it uses— including electricity, heating and cooling requirements.
Hourigan Construction has worked closely with its project partners in the Preconstruction phase to ensure the Center will be a net zero energy facility. The following three technologies will produce renewable energy sources to contribute to this goal:
1. Photovoltaic array provides solar energy
Photovoltaic arrays contain solar cells that convert sunlight directly into electricity. These “solar panels” will collect the energy created by natural sunlight and distribute it for use throughout the building, as each electrical and mechanical operating system requires. The Brock Environmental Center will require a 39 KW photovoltaic array mounted on the roof of the main building. It will consist of 162 panels creating a total annual output of 124,000 kbtu and will be mounted directly to the standing seam roof panels.
2. Wind turbines produce energy from off-shore winds
The Brock Environmental Center’s location adjacent to the Chesapeake Bay is ideal for harnessing wind energy. Two 70’ tall wind turbines with 29’ diameter rotor blades will be powered by the consistent velocity of the off-shore winds from the Chesapeake Bay and will create a total annual output of 84,000 kbtu. The turbines will collect and distribute the wind energy to the building’s electrical and mechanical operating systems in a similar fashion to the photovoltaic system.
3. Geothermal wells create cool water for the mechanical system
Geothermal energy uses heat from the Earth to heat and cool buildings. The Brock Environmental Center will take advantage of this renewable energy resource by building eighteen 300’ deep geothermal wells, 6” in diameter. Located adjacent to the building’s north side, each will produce 1.5 tons of cooling (total of 27 tons) for the building’s mechanical system.
The geothermal system works by circulating cool ground water through the wells and into the mechanical system. The water is used for the cooling cycle of the HVAC system and then recycled back through the wells, which rejects the heat back into the ground that was gained through the cooling process of the mechanical equipment. This system replaces the need for a “cooling tower” or a “chiller” to create cool water for the mechanical system, thereby eliminating the electrical requirements to operate the equipment and saving energy.
The Energy Petal has been one of the main focuses of the Living Building Challenge due to the extensive research required by Hourigan Construction and the team to meet the requirements. These three renewable energy resources will provide much of the energy needs of the Center. In our next post we will review two additional strategies that will be used to address the requirements of the Energy Petal.