Designers Create Carbon Neutral Building Prototype

ST. LOUIS – International architectural firm HOK and energy and daylighting consultant The Weidt Group have developed a prototype for a market rate, net zero emissions Class A commercial office building in St. Louis.
The speculative building, dubbed Net Zero Cou2t, is located on a potentially developable site in midtown St. Louis’s emerging biotech corridor, near Saint Louis University and the Barnes-Jewish Hospital at Washington University Medical Center. The team chose the site for its four-season weather, 81 percent coal fuel profile and cheapest electricity rates in the country, reasoning that if it could design an affordable carbon neutral building in such a harsh environment, it could replicate replicate its process in any location.
The team says that Net Zero Cou2t reduces carbon emissions by 76 percent with “only minor” additional first costs compared to a conventional office building. On-site renewable energy systems such as a 51,800 square foot rooftop and wall-mounted photovoltaic panels and 15,000 square feet of solar thermal tubes provide the remaining clean energy required to reach zero carbon emissions.
Buildings are responsible for 39 percent of the carbon emissions in the United States.
The 170,734 square foot building consists of two four-story, 300-foot long office structures oriented East-West and joined by two 60-foot links that enclose a 60-foot wide landscaped courtyard. The North and South facades feature daylight glazing with insulated opaque areas to leverage natural light and the East and West facades are largely solid, blocking glare at low sun angles, the team says.
The building’s solar thermal and photovoltaic system is projected to produce energy cost savings of $184,567 a year, leaving an annual energy cost of $2,418 at current utility rates. The building will be illuminated without electricity during daylight hours.
Payback for the investment required to reach carbon neutrality compared to a LEED-certified baseline building is projected at 12 years if the rise in fuel costs outpaced general inflation by four percent a year. The payback in many other parts of the country where electricity is more expensive is projected at less than 10 years.