Whipple Building's $170M Rehab Already Paying Off
Geothermal wells, new mechanical systems have reduced energy and water use more than 40%.
FT. SNELLING, MN – Four years and $170 million later, the Recovery Act renovation of the Bishop Henry Whipple Federal Building – completed in August 2014 – has already provided a 40% reduction in energy use and 53% reduction in water use versus a 2009 baseline.
The building's first major upgrade since its construction in 1969, the project replaced mechanical, electrical, and plumbing systems with energy-saving technologies while also modernizing interior spaces with increased daylighting, updated lighting fixtures, and improved furniture and signage (see photo gallery).
One of the project’s most unique features was the installation of geothermal ground-source technology, which uses the near-constant temperature of the Earth to heat and cool the building.
In summer, a glycol solution circulates through the pipes in the ground and releases its heat into the earth. After cooling off below ground, the solution returns to the building, absorbs heat from the air, and returns into the ground to be cooled once more. In winter the system works in reverse, with the Earth's insulation warming the glycol before sending it on it's way to help heat the building.
The Whipple's geothermal installation is the largest in Minnesota and one of the largest for GSA. Nearly 800 vertical heat exchangers are located beneath the building’s parking lots. Each exchanger is 250 feet deep, forming a network of more than 75 miles of piping below the surface.
Back above ground, the Whipple's most noticeable changes are new landscaping and a more welcoming entryway – a taller, lighter, glass version, which improves lighting, security, and flow. The entry vestibule itself has been upgraded with all glass doors, better lighting, and enhanced security.
The primary staircase has moved to a more prominent location in the lobby for better access to the building’s amenities, which now include a new convenience store, credit unions, renovated cafeteria, and an outdoor terrace.
The project's green, energy-saving additions include:
- A solar glycol-based heating system, designed to provide 50% of the energy needed for the building’s domestic hot water system
- A rooftop photovoltaic system to reduce the building’s power usage
- New computerized lighting systems and controls
- New exterior wall insulation and windows
Expected to result in a consistent 30% reduction in energy use, the facility's improvements earned the Whipple building a Leadership in Energy and Environmental Design (LEED®) Gold certification, the second highest certification possible from the U.S. Green Building Council. The renovation also won a Top Project of 2014 Award from Finance & Commerce magazine, Minneapolis.