Dubuque County Courthouse – Dubuque, Iowa
38,000-square-foot, five-story, 105-year-old structure listed on the National Register of Historic Places
Geothermal heat pump system:
- 106-ton Mammoth brand.
- 100 console-type water source heat pumps sized from ¾ to four tons each.
- COPs of 3.88 and EERs ranging from 17.7 to 22.6.
Geothermal loop system:
- Open loop well at 94 feet deep.
- 350 gallon-per-minute capacity.
- Variable speed drive on well pump.
Annual energy costs:
First-year savings to taxpayers was $6,000 in natural gas, $3,000 in water and $2,000 in electricity.
At a glance:
- Former boiler and cooling tower heap pump system provided existing piping to each console, minimizing disruption of building and occupants.
- Building now has increased comfort with simultaneous heating and cooling – critical in Iowa’s volatile spring and fall weather.
- New system uses only 10 percent of the old, gaining valuable floor space in a historic building.
- Maintenance needs were reduced considerably, allowing staff spread time at other county facilities.
System performance report:
GeoExchange System Monitored Performance: Dubuque County Courthouse – Final Report by CDH Energy
[PDF format – 20 pages, 393KB]
Steven Ulstad Architects – Dubuque, Iowa
Gilmor & Doyle, Ltd. – Waterloo, Iowa
Giesler Brothers – Dubuque, Iowa