The renovation of the Todd County Historic Courthouse in Long Prairie, completed in June 2012, includes a new heating and cooling system, making use of the latest energy-efficient technology. The Historic Courthouse joins several other public buildings in Central Minnesota including the Wilkin County Courthouse and Onamia Public Schools using geothermal energy systems to heat and cool their buildings.
Ground-source heat pumps provide whole-building heating and cooling using the earth’s heat, hence the name “geo-thermal”. The earth’s temperature near the surface is 58 degrees year round.
More than two dozen geothermal heat-exchanger wells were sunk under the Historic Courthouse parking lot by KJohnson Construction at the beginning of the renovation project during the summer of 2011. Four heating and cooling loops composed of 15,500 feet of geothermal piping were installed in the ground connecting the wells. The loops are filled with an environmentally safe antifreeze solution which transfers heat or cold fluid through the system, and run into and out of the building, bringing heat in winter and cooling in summer. Click here to see more info and photos.
Twenty-seven heat pumps are installed in the ceilings of the first and second levels of the Historic Courthouse. They transfer the heat or cooling from the antifreeze solution to the air, and an air handling system circulates the heated or cooled air throughout the building. There is no need for a furnace or for an air conditioning system.
A Metasys computerized building management system (BMS) designed by Johnson Controls allows county custodial staff to operate the Historic Courthouse heating and cooling system, as well as the systems of three other related county buildings, from one computer station. Staff can change temperature settings, change the mix of warm and cool air circulating in the building, and monitor motor speeds.
The new equipment in the HVAC system includes six new energy-efficient motors equipped with variable frequency drives, or VFDs. The VFDs allow the motors to run at a range of speeds, not just “on” or “off”. This feature saves thousands of kilowatts of electricity over a year’s time.
In addition to the geothermal system, the Historic Courthouse now has historically accurate, energy-efficient windows paid for by a grant from the Minnesota Historical Society.
The construction managers for the Historic Courthouse renovation were Contegrity Group, Inc., of Little Falls. Earl Fuechtmann of Contegrity supervised the renovation. In a letter dated July 3, 2012, congratulating Todd County Commissioners on the completion of the renovation, Fuechtmann wrote that the firm felt “pleasure and pride that we were chosen to help” with the massive project. Collaborative Design Group Inc. were architects for the project.
The renovation of all levels of the Historic Courthouse, originally built in 1883, cost about $4.3 million. Most of the cost was covered by bonds sold by Todd County, following a 2010 voter referendum that approved renovating the Courthouse and selling bonds to pay for the work. Many county offices are now located in the Historic Courthouse, which reopened on July 3, 2012 after being closed since 2006.
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