Montana/Dakotas

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Missoula Field Office Goes Green 

Story and photo by Marilyn Krause, Western Montana Zone

Chuck Bridgement with HVAC system 

 Chuck Bridgeman, Missoula assistant field manager, explains how the ground source heat pump system works. The unit in the foreground is the actual “heat exchanger.”

The Missoula Field Office spent a good share of the winter in an office undergoing a major upgrade to the heating and cooling system. As inconvenient as it was, the employees knew their sacrifice would pay off in the future with less energy consumption.

Johnson Controls installed a ground-source heating/cooling system under an “Energy Saving Performance Contract” (ESPC). The BLM did not pay any up-front costs for the system – the contractor is paid over the next 20 years through the energy savings (reduced utility usage) the new system provides. ESPCs are an option only for BLM-owned buildings, not leased offices. To measure and verify the changes and utility reductions, a new electrical metering system was also installed.

Ground-source heat pumps are electrically powered systems that tap into the stored energy of the earth. These systems use the earth’s relatively constant temperature to cool the building in the summer and heat it in the winter.

The Missoula system is state of the art. It is run by a stand-alone computer that manages the two zones – east and west halves of the building. An additional feature is the carbon dioxide detection system – when more employees are in the building and the C02 level rises, dampers automatically open to let in fresh air. In addition, sensors monitor the temperature at different places in the building and adjust airflow accordingly. 

“With this system, we have increased air movement around the office, compared to the old system,” stated Chuck Bridgeman, assistant field manager. “It takes some getting used to, but our employees are comfortable.” 

To save additional energy, the Missoula Field Office also had an on-demand hot water heating system installed and replaced all the ceiling fluorescent lights with two bulb units rather than four. The new light fixtures have the same amount of lighting capability but use much less energy.