Police Station Proposal - Part IV - Geothermal

This is the fourth in a series of posts covering the proposed Gilford Police Station Addition and Renovation.

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While the plans for the expanded police station show the use of geothermal heating and cooling, also called a ground-source heat pump system, not too many people are familiar with the concept or how it will be applied.

Such geothermal systems have been around for decades, and the concept has been around for almost a century. Basically stated, a geothermal heating/cooling system either draws heat from the ground to heat a building, or dumps heat into the ground to cool it. An excellent overview of geothermal systems can be found here, showing systems large and small.

Basic heating and cooling systems of the type presently used at the town hall/police station usually consist of a furnace (or three in this case), a circulating pump, an external air conditioning chiller (combination compressor and heat exchanger), heating/cooling registers (the heating/cooling/fan units in each room), and a water loop. Water heated by the furnaces or cooled by the chiller is circulated through the water loop, providing either hot or cold air from the register units, depending upon the season.

Geothermal systems replace the furnaces and the external air conditioning chiller with a well, a well pump, and a liquid-to-liquid heat exchanger/compressor. There's no combustion needed to heat (meaning no heating oil, natural gas, or propane needed) and no big clunky, noisy, inefficient air conditioning condenser outside for cooling.

Because of the efficiency of geothermal systems, heating and cooling costs are considerably lower than conventional systems. A comparison of heating and cooling costs can be seen here. Though based on slightly outdated information (heating oil is assumed to cost $3/gallon, propane is assumed to cost $3.32/gallon) it isn't unreasonable to assume energy prices will be the same or higher by the time the police station addition and renovation is completed.

For a somewhat more in-depth look at geothermal heating and cooling systems, a presentation made to the New Hampshire State Employees Association by Water Energy this past December can be seen here (It's approximately 3.3MB in size). While it is aimed more at residential systems, the same principles and efficiencies apply to the police station addition and renovation.

If there are any questions about the proposed geothermal HVAC system for the police station, please feel free to use the comment system or e-mail us at the link under Contact Us.