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Basic objective of the GeoClip™
The GeoClip™ is used to position the
u-bend pipes of a vertical heat exchanger at the borehole
wall and is designed to separate the pipes as far apart as
possible. By achieving these objectives, you have installed
a vertical heat exchanger with the highest heat transfer rate
possible for that location, pipe size, grouting material,
borehole size and depth.
Problems associated with a standard vertical
heat exchanger installation:
Low Thermal Conductivity Grout: Most
state regulations require using a bentonite based grout to
seal the borehole. This bentonite based backfill has
a very low thermal conductivity (or low heat transfer rate).
Because the u-bend pipes are embedded in this insulating material,
a deeper borehole must be drilled to achieve the required
energy exchange with the earth.
U-bend Pipe Energy Interaction: In
a standard installation, the u-bend pipes are typically close
to each other or even touching each other within the borehole.
When the u-bend pipes are close together, they interfere with
each other's ability to exchange energy with the surrounding
soil. This effect also requires vertical heat exchanger
depths to be longer than necessary.
How the GeoClip™
eliminates the negative effects of low thermal conductivity
grouts and u-bend pipe energy interaction:
The picture below shows a standard vertical
heat exchanger installation on the left compared to a GeoClip™
installation on the right. As illustrated the GeoClip™
installation positions the pipe next to the borehole wall
eliminating the insulating effects of the backfill grout.
The GeoClip™ installation also separates the u-bend pipes
as far apart as possible within the borehole reducing energy
exchange interference between the two pipes. This pipe
positioning provides superior heat transfer characteristics
compared to a standard installation.
The diagram below, illustrates three types
of vertical heat exchanger installations. The first
configuration, has a standard installation where the pipe
placement, at its best, is evenly spaced in the borehole and
the borehole is sealed with a standard 20% solids bentonite
grout. The second configuration, also has evenly spaced
u-bend pipes in the borehole and is backfilled with a thermally
enhanced bentonite grout. The third configuration, utilizes
the GeoClip™ which positions the u-bend pipes against
the borehole wall directly across from one another and is
backfilled with a standard 20% solids bentonite grout.
As illustrated, once energy is either absorbed
or rejected through the u-bend pipes, there is a significant
difference between the three types of installations and their
ability to exchange energy with the earth. The first
installation, has difficulty exchanging energy with the earth
because it is surrounded in insulation which is the 20% bentonite
grout.
The second installation, also has difficulty
exchanging energy with the earth, even though it is surrounded
with less insulating grout because of all the energy interference
between the two u-bend pipe which are too close together.
The third installation or the GeoClip™
installation, has no difficulty in exchanging energy with
the earth, regardless of the backfill or bentonite grout used.
Because the pipes are at the borehole wall, the insulating
effects of the bentonite grout have virtually no effect on
the u-bend pipes. And, because the pipes are directly
across from one another, there is little energy interference
between the u-bend pipes.
The GeoClip™
installation is clearly the best engineering design possible. Click
on to savings
to see how much money you can save by using GeoClip™.
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