Moderating the Extreme. Bismarck, North Dakota, gets seasonally frigid, but the city government continues operating during such harsh temperatures, supported by the geothermal heat pumps that circulate milder subterranean temperatures from beneath the Century Center. Photo from Century Center
Fast Facts
Location: Bismarck, North Dakota
System Size:
- Heats and cools 112,617 square feet of floor space
- Has 224 individual heat pumps
- Consists of 286 wells
- Occupies an area of about 2 acres
Download the full case study for additional fast facts.
Drilling Another Type of Well in North Dakota
Beneath North Dakota there is a rich energy reserve sufficient to heat and cool buildings across the state. With just boreholes, pipes, and heat pumps, this dormant energy source is easy to tap into. We’re not talking about the oil North Dakota is known for; geothermal is another energy option, even closer to the Earth’s surface. In 2003, the state tapped into geothermal energy for the Century Center in its capital city of Bismarck.
Although not the first North Dakota state building to use geothermal heat pumps (GHPs), the Century Center is the largest, providing enough space for about 400 employees who work in a variety of state agencies. The upfront cost of the geothermal installation was high, but the system saved enough energy to offset initial costs and be paid off within 2.5 years. More than 20 years later, the savings hum on.
Consistent and Quiet
Within the offices, perhaps employees might notice a gentle click when a pump turns on or off, but the geothermal system is otherwise imperceptible. It is also invisible: The pipes loop beneath the north parking lot and enter the building’s envelope from below. There are no unsightly boxes outside, and no droning machines inside.
Maintenance and operation have also been a breeze. Even as the building’s heat pumps meet their nominal lifetime of 20 years, the Century Center has only needed a couple dozen replaced out of 224 pumps. And in the deepest prairie freezes, the system has not needed repairs.
Heat pumps in the Century Center in Bismarck, North Dakota, keep state employees comfortable in the offices above as air circulates reliably, silently, and out of sight in pipes below. Photo from Century Center
Unique Features:
- A separate heat pump system thaws sidewalk ice
Energy Use: 781,000 kWh per year
Funding Source: State of North Dakota
Comfort in Brutal Weather
The Century Center’s full windowed facade takes in southern light year-round, such that the front often requires cool air in the winter, while the back requires heating. In the coldest weather, which sometimes reaches -40°F, the whole building needs heating, as does the sidewalk, which sits above an auxiliary heat pump system that deices during typical winter temperatures.
Summers are also not always mild, but the geothermal system cools the building up to temperature of 110°F. Through these extremes, the system is not stressed; it continues to operate and keep state employees comfortable—a testament to the suitability of geothermal for Bismarck and beyond.
“Overall, it’s a great system. It works well in extreme temperatures but is most efficient between 25 and 50° (Fahrenheit) when parts of the building are heating, and others are cooling.”
Mike Schumacher, Facilities Manager at the Century Center
Contacts:
For questions about this case study, contact Michael Schumacher, mschumacher@nd.gov.
For any website technical issues or general questions about geothermal heat pumps, contact DOE.Geothermal@ee.doe.gov.
Printable Version
Download the printable Century Center case study or visit the Geothermal Heat Pump Case Studies page to see more examples of geothermal heat pumps in action.