Geothermal Heat Pump Case Study: Greensburg, Kansas, City Hall

A Modern Oz: Better, Stronger, Greener

In May 2007, a violent tornado pummeled Greensburg, Kansas, a farming community of 1,200 residents at the time. When the tornado’s 200-mile-per-hour winds settled, 95% of the city had been destroyed or severely damaged—including City Hall. However, Greensburg turned this disaster into an opportunity to rebuild “better, stronger, and greener,” implementing renewable energy and energy-efficient practices in new and reconstructed buildings.

Greensburg’s new City Hall is one of these better, stronger, greener buildings. Rebuilt between 2008 and 2009 to LEED Platinum standards, the 4,700-square foot building boasts an open-loop, vertical geothermal system, which heats and cools the building’s council chambers, administrative offices, and gathering spaces. 

Lessons and Learning Curves

City Hall’s open-loop geothermal system—the only open-loop system in town—pumps groundwater up from a well, uses the water to transfer heat to or from the building, and then discharges the water back into the ground. Other Greensburg buildings, including the hospital, county courthouse, sheriff’s office, and K-12 school, have closed-loop geothermal systems, which transfer heat by circulating fluid through a closed network of pipes buried in the ground without any groundwater being added or removed.

The city chose the open-loop system because it was the most affordable. In addition, open-loop geothermal systems can be more efficient and cost-effective, simpler to install, and require less land. However, the open-loop system had its maintenance challenges. When it was installed in 2009, not many heating, ventilating, and air-conditioning contractors in the area had experience working on a geothermal system, nor did Greensburg municipal building staff. 

However, today, geothermal heat pump (GHP) systems are more common, and more contractors know how to maintain and repair them. The city also trained building staff on the system’s day-to-day upkeep and to be familiar enough with the system to know what needs to be fixed when issues arise. Overall, Greensburg’s city officials have been satisfied with City Hall’s geothermal system. 

“In our specific case, even though we’ve experienced some challenges with our open-loop system, it has still been energy-efficient and worthwhile,” said Greensburg City Administrator Stacy Barnes.

From Post-Cyclone Ruins to “Emerald City” of Sustainability

The 2007 tornado was devastating, but it came with a silver lining: It gave the city a chance to design a new building with features that will make the building clean, comfortable, and efficient well into the future. Greensburg City Hall’s geothermal system is just one of the building’s several eco-friendly features. Humidity sensors prompt the building’s geothermal heat pumps to slow fan speeds and dehumidify the building, windows and skylights maximize sunlight and reduce the building’s electricity consumption, and a rooftop solar photovoltaic system generates 4.8 kW of on-site electricity. 

Beyond City Hall, low-flow fixtures, native plantings, and rainwater collection systems minimize Greensburg’s water consumption. Wind—the same force of nature that nearly wiped the city off the map in 2007—now provides all of Greensburg’s electricity. In fact, the city has run on 100% renewable energy since 2008. Thanks in part to its adoption of geothermal and these other eco-friendly practices, Greensburg has become a model for communities recovering from disasters—or simply looking to go better, stronger, and greener. 

“The City of Greensburg is very pleased with the geothermal heat pumps we have deployed in our City Hall and other municipal facilities. Their reliability and efficiency have saved the city tens of thousands of dollars in energy costs over the past 15 years, and we expect them to continue to pay dividends for the city and its residents for many years to come.”

Matt Christenson, Mayor, City of Greensburg

Contacts: 

For questions about this case study, contact Matt Christenson, mayor@greensburgks.org.

For any website technical issues or general questions about geothermal heat pumps, contact DOE.Geothermal@ee.doe.gov.