Evaluate Your Site for a Geothermal System
Geology
Factors such as the composition and properties of your soil and rock (which can affect
heat transfer rates) require consideration when designing a ground loop. For example,
soil with good heat transfer properties requires less piping to gather a certain amount
of heat than soil with poor heat transfer properties.
The amount of soil available contributes to system design as well — system suppliers
in areas with extensive hard rock or soil too shallow to trench may install vertical
ground loops instead of horizontal loops.
Hydrology
Ground or surface water availability also plays a part in deciding what type of ground
loop to use. Depending on factors such as depth, volume, and water quality, bodies of
surface water can be used as a source of water for an open-loop system, or as a
repository for coils of piping in a closed-loop system.
Ground water can also be used as a source for open-loop systems, provided the water
quality is suitable and all ground water discharge regulations are met.
Before you purchase an open-loop system, you will want to be sure your system
supplier/installer has fully investigated your site's hydrology, so you can avoid
potential problems such as aquifer depletion and groundwater contamination.
Antifreeze fluids circulated through closed-loop systems generally pose little to no
environmental hazard.
Land Availability
The amount and layout of your land, your landscaping, and the location of
underground utilities or sprinkler systems also contribute to your system design.
Horizontal ground loops (generally the most economical) are typically used for newly
constructed buildings with sufficient land.
Vertical installations or more compact horizontal "Slinky™" installations are often used
for existing buildings because they minimize the disturbance to the landscape.
Alternative-Heating-Info.com
Because shallow ground
temperatures are relatively
constant throughout the
United States, geothermal
heat pumps systems can be
effectively used almost
anywhere.
However, the specific
geological, hydrological, and
spatial characteristics of
your land will help your local
system supplier or installer
determine the best type of
ground loop for your site.
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