Loop Systems
A geothermal heat pump or geoexchange system is actually comprised of three separate systems:• Ground loop for extracting or rejecting heat into the ground to warm or cool the building as needed
• Heat pump itself that concentrates the heat
• Delivery system in the form of air ducts or a radiant floor system.
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Horizontal Loop When adequate land surface is available, this is the most cost effective closed loop system. |
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Vertical Loop Image The ideal choice for a geothermal heat pump when land is limited. Well drilling equipment is used to bore small diameter holes from 100 to 400 feet deep. |
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Pond (Lake) Loops Economical when a large body of water is available. Coils of pipe are simply placed on the bottom of the pond or lake to capture the geothermal energy. |
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Open Loops (Well-Water Systems) In ideal conditions, an open-loop application can be the most economical type of geothermal system. These use ground water from a well as a direct energy source. |
The term “closed loop” is used to describe a geothermal system that uses a continuous loop of special buried plastic pipe as a heat exchanger. The pipe is connected to the indoor heat pump to form a sealed, underground loop through which a heat transfer solution is circulated. Unlike an open loop system that consumes water from a well, a closed loop system recirculates its heat transferring solution in pressurized pipe.
Where can this loop be located?
That depends on land availability and terrain. Closed loops are trenched horizontally in yards adjacent to the home if the yard is large enough. For smaller yards loops can be installed vertically. Horizontal loops are typically significantly less costly to install than vertical loops.
How long will the loop last?
Closed loop systems should only be installed using the appropriate high density polyethylene pipe. Properly installed, these pipes will last over 50 years. They have good heat transfer properties and unlike copper tubes used in DX systems, they are inert to chemicals normally found in soil. PVC pipe should not be used under any circumstances.