Open & Closed Loop Geoexchange Systems
Additional Information
Commercial
Case Studies/Projects
Geothermal Energy
Energy Resource Station
NBCIP
Lighting Research Center
Open Loop System
This type of system uses wells or a body of water as the source of heat exchange fluid that circulates directly through a heat exchanger in the building. Once it has circulated through the heat exchanger, the water returns to the ground through the recharge well or the body of water. This option is practical only where there is an adequate supply of relatively clean water, and all local codes and regulations regarding groundwater discharge are met.
Closed/Pond Loop System
Since water transfers heat much better than soil, closed loop systems are often located in lakes or ponds by submerging GeoExchange loop coils in the water. Since these types of loops usually require minimal excavation, installation costs can be reduced. Impacts on aquatic systems have been found to be minimal. For commercial applications a minimum pond depth of 12 feet is recommended. Generally, thermal loading should not exceed 10 tons per acre; however, some specially designed installations may approach 100 tons per acre.
Facts
- Both the heat pump and the piping systems of GeoExchange systems are built to last. All piping is connected by a special heat fusion process to form strong joints. Properly installed, the underground/underwater piping systems will last 75 years or longer.
- The heat pump equipment inside the building needs no combustion fuel and is safer and more reliable than other types of conventional heating equipment. The economic service life of the heat pump equipment is considered to be 19 years.
- Iowa has an excellent balance between heating and cooling seasons which increases the effectiveness of a GeoExchange system. Iowa case studies indicate a 30% to 50% reduction in site energy use
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Facts
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