About Our Geothermal Heating & Cooling System
The Alpine Orthopedics and Sports Medicine building, a 10,900-square-foot medical center, is one of the first medical centers in South West Montana to install geothermal technology.
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This system was provided by Bozeman-based Energy 1.
Building Type:
The Alpine Orthopedics and Sports Medicine building, a 10,900-square-foot medical center, is one of the first medical centers in South West Montana to install geothermal technology.
System:
- 20-ton system
- 8 heat pump units with 8 heating and cooling zones
- Geothermal supply and rejection well drilled to the south east and north east of the building, respectively.
GSHP Benefits:
- Lower utility costs
- Improved comfort
- Reduced maintenance
- Environmentally safe
- Short term payback
Open Loop Geothermal
The geothermal system featured in the Alpine Orthopedics & Sports Medicine building uses open-loop technology to transfer energy from one area to another. Simply put, it uses ground water as a heat source in the winter, and as a heat sink in the summer. Such systems work in the same fundamental manner as all heat pumps (including refrigerators, air conditioners, freezers, etc.). The primary difference, and perhaps greatest fundamental advantage, that ground source heat pumps have over standard heat pumps and air conditioners, is that they utilize the relatively stable and moderate temperature of the earth or groundwater to transfer heating and cooling to a building.
In northern climates such as ours, ground source heat pumps move 3-4 times more energy than they consume in heating mode, and 5-6 times more energy than they consume in cooling mode. The energy they do consume is limited to electricity, to power pumps, compressors, and fans. As a comparison, combustion of a natural gas furnace system produces up to about 92% of the energy that it uses. Maintenance costs, a critical consideration with commercial mechanical systems, are another significant benefit to geothermal based systems. Geothermal systems maintain a significantly lower maintenance cost per square foot compared to conventional systems. This is mainly due to the heat exchanger not having to experience wide temperature variations, airborne dust contamination, or accidental damage, all of which traditional evaporator coils are very prone to.
The diagram above depicts how an open loop ground source heat pump operates while in heating mode. Groundwater is pumped from a local underground source to the heat pump. From here, it is used to warm a special fluid refrigerant that is very cold and in liquid form. As the liquid warms, it begins to boil and evaporate. The vapor is then compressed, which causes the temperature of the refrigerant to increase dramatically. This heated vapor then passes through another heat exchanger where it either heats forced air, or hot water for radiant heating, for distribution throughout the building. This transfer of heat cools the vapor causing it to condense to a liquid form. Finally, the liquid passes through an expansion valve, which causes it to cool further so it can once again absorb heat from the earth. In cooling mode, the cycle is simply reversed.
