Largest zero-energy office building opens in Colorado
According to an article by Jim Witkin with the New York Times, the federal government recently finished construction on a zero-energy office building. The 222,000-sq-ft Research Support Facility is located on the National Renewable Energy Laboratory campus in Golden, Colo. The building will officially open to its 800 employees in late August.
Due to the passive design techniques and technologies, the facility will consume 50% less energy than buildings constructed to current commercial codes. The remaining power will be generated onsite from solar panels, which allows the building to operate at an annual net-zero energy basis.
The building’s east-to-west orientation and narrow 60-ft width bring daylight into the interior work spaces and one of the building’s automation systems sends the occupants a message to notify them when to open or close their windows, based on a comparison between inside and outside temperatures.
The firm Stantec was the sustainable design consultants for the project and they designed a smooth concrete layer facing the interior office space, which absorbs heat during the day to keep the interior cool and then releases the heat when the temperature drops at night.
A low-energy radiant heating and cooling system will further control the interior temperatures. Instead of a traditional forced air system to heat and cool the building, the radiant system heats or chills the building mass itself using water pipes in the concrete floor slabs that circulate hot or cold water.
Corrugated metal panels cover much of the building’s south exterior, capturing solar heat and funneling it to a concrete thermal labyrinth beneath the building that also serves as the foundation. The labyrinth stores the heat or can release it into the building when additional heating is required during the coldest months.
Much of the building is composed of recycled materials, including some from the runway of Denver’s defunct Stapleton Airport. Reclaimed steel natural gas pipes are used as structural columns. The lobby is lined with wood recovered from Colorado pine trees destroyed by a bark beetle infestation.
The Department of Energy expects the project to get a platinum rating from the USGBC’s LEED program. Although more expensive than conventional commercial buildings, the new building’s cost, $259 per square foot, is in line with that of other LEED buildings.