Generating
More Heat
Product aims to maximize
the effectiveness of geothermal systems.
___________________________________________________ By Lana Straub
remember attending a conference on green energy in 1997
and bringing the ideas home
to west Texas. I was told,
“Those are nice ideas but they won’t
ever come to pass out here—this is oil
country.”
But when oil prices began to skyrocket
in 2004, more and more green technology
began to prosper. I look out my window and
the flat west Texas land of my childhood
that used to be home to only cotton fields
and pump jacks are no longer flat. I see
wind turbines as well.
And even though the price of oil has
recovered from its skyrocketed prices, it
is undeniable that green technology has
made its mark and will continue to be in
our futures. Homeowners across the country
are finding comfort in green technology and are using it to
heat their homes in the form of radiant geothermal heat.
I
What Is a GeoClip?
GeoClip™ is a vertical heat exchanger enhancement system. As you know, the goal of a geothermal heat loop system
is to exchange as much heat with the earth as possible to
maintain an ambient temperature in the facility using the system. The heat generated from the system can be used as an
alternative method of heating or cooling a home or business.
As the exchange takes place, excess hot air is released into the
earth and cool air is brought back to the surface. In the alternative, warm air is pulled from the earth and brought to the
surface to create heat in a room that might otherwise feel cool.
To achieve this heat exchange, a series of U-bend pipes are
placed inside a borehole and energy generated from the earth
is put into the exchange system. The basic objective of the
GeoClip product is to space the piping in such a manner as to
maximize the effectiveness of the heat exchanger and help the
Lana Straub, with a background in legal and financial aspects
of small business, is the office manager of Straub Corp. in
Stanton, Texas, an environmental and water well drilling firm
owned and operated by her family for more than 50 years.
She can be reached at [email protected].
contractor achieve the highest heat transfer
rate possible.
It was designed by Kris Jeppesen and
patented in 1999. GeoClip is manufactured
and distributed by Geothermal Bore Technologies Inc., which is located in Loretto,
Minnesota. The product is available in two sizes,
those fitting ¾-inch and 1-inch U-bend pipe.
Advantages of Using GeoClip
Opinions vary in the water well industry as to the
benefits of GeoClip in the installation of a geothermal heating system. Low thermal conductivity
grout is one problem that GeoClip attempts to
solve. Research studies have shown that bentonite grout alone has a low thermal conductivity.
When geothermal pipes are buried in the bentonite
grout, the heat transfer rate diminishes and the system becomes less efficient.
To compensate for the loss of energy exchange, often the
solution is to drill a deeper borehole and use more piping in
an attempt to create more surface area for the system to compensate for the lost heat exchange. A deeper borehole and
increased piping can mean greater expense to the customer
and added time and cost to the project.
GeoClip attempts to solve this problem by “placing the pipe
next to the borehole wall, eliminating the insulating effects of
backfill grout,” explains GBT in its literature. The position of
the pipe could be the most important part of the geothermal
heating system. “Pipe positioning near the borehole wall ensures maximum energy transfer in a geothermal application.”
The closer the pipe is to the borehole wall, the more effective
the heat exchange and the more efficient your heating/cooling
system (see borehole on right in figure on this page).
Energy interaction between the parallel piping in the Ubend system has also become an issue. If the pipes are too
close together, they will exchange energy with each other,
limiting the efficiency of the system. GeoClip products are
designed to keep taunt piping in the borehole and position
the parallel pipes as close to the borehole wall as possible.
This alignment allows the geothermal fluid to interact with the
borehole wall and keeps the piping separated to minimize the
interaction between the fluids in the pipes.
HEAT/continues on page 26
24/ February 2009 Water Well Journal
NGWA.org
Proper Installation of GeoClip
HEAT/from page 24
Research and testing have shown that the
pipe positioning created by the use of the
GeoClip “provides superior heat transfer
characteristics compared to a standard installation,” according to GBT, including
installations that use thermally enhanced bentonite grout. When using
the GeoClip in field testing, improved heat transfer rates have been
recorded for both the ¾-inch Ubend and the 1-inch U-bend pipe.
Likewise, increased heat exchange has also
been recorded in varying borehole sizes, those ranging from
4½ inches to 6 inches in diameter.
The table prepared by GBT illustrates what the company
says are the increased heat exchange percentages realized
when using GeoClip in a vertical heat exchanger.
Literature provided by GBT adds that testing has proven
that the right combination of borehole size, GeoClip use, and
grouting material
can increase your
output from 0.76
Btu/hr ft °F to 1.55
Btu/hr ft °F in the
Pipe positioning near the bore wall
same size bore—
ensures maximum energy transfer in
doubling your heat
a geothermal application, according
exchange and your
to GBT.
efficiency.
26/ February 2009 Water Well Journal
Use of GeoClip in the installation process
has been an issue debated by contractors at
industry conventions and shows. Some individuals swear by them; others do not.
One issue that might stir the debate
is understanding the proper installation of GeoClip. GBT provides indepth installation instructions with
step-by-step photos as well as a
video demonstration of GeoClip installation on its Web site at www.
geoclip.com. You can also find
GeoClip installation videos of varying caliber on Mefeedia, a
new video search engine similar to Google, at
www.mefeedia.com.
Here is the extremely quick version of GeoClip installation
without pictures.
1.
2.
3.
4.
5.
Drill a 4½-inch, 5-inch, or 6-inch borehole.
Attach anchors or iron (sinker) bars to the base of each
U-bend.
Attach GeoClips while pipe is on the ground or while
uncoiling U-bend pipe and inserting it into the borehole.
Take out compressed GeoClip and attach one to the U-bend
pipe about every 10 feet, starting 10 feet above the base of
the U-bend.
Snap each pipe of the U-bend to the GeoClip with the
spring wire facing upward and the tremie hooks facing
toward you.
NGWA.org
Snap tremie pipe into the GeoClip’s tremie hooks.
7. Remove plastic retaining clip before insertion into the
borehole.
8. Install GeoClip assembly into the borehole until desired
depth.
9. Pull tremie pipe out of the borehole slowly as grout level
rises.
10. As tremie pipe is removed, GeoClip springs are tripped and
pipes are pushed against the borehole wall.
6.
Proper installation is important to achieve superior performance from your geothermal system. The GeoClips spring
into action once the grout piping is removed, guaranteeing
Increase in heat transfer rate of borehole
using the GeoClip
¾-inch U-bend
4½-inch
bore
5-inch
bore
6-inch
bore
74.45%
78.65%
86.15%
1-inch U-bend
NGWA.org
4½-inch
bore
5-inch
bore
6-inch
bore
65.82%
69.81%
76.94%
Tooling Up
For more information on GeoClip and its applications,
contact:
Geothermal Boring Technologies Inc.
Attn: Rick Nash
6450 Pioneer Trail ● Loretto, MN 55357
(800) 588-0608 ● (763) 432-4019 ● (763) 432-4021 (fax)
that the borehole is completely grouted, eliminating air pockets and voids in the grout. The spring action also ensures
pipe positioning close to the borehole wall that facilitates
maximum heat transfer and eliminates the problem of heat
exchanger insulation commonly caused by standard grouts.
Its V-shaped design positions the U-bend piping as far apart as
possible, preventing and virtually eliminating any heat transfer interference between the piping.
If we learned anything from the last election, it was the
drumbeat of the energy crisis and our personal effect on the
way energy is used globally. We have to find alternatives that
use less energy and use the energy we produce in the most
efficient way possible. Efficiency is the key to any energy
application.
Oftentimes, optimum efficiency is unobtainable and we
must settle for less. But help might just be on the horizon.
GeoClip products aim to provide a remedy to the dilemma of
efficiency loss. Who knows? You just might generate more
heat for your customers—and more profit for your wallet.
WWJ
Water Well Journal February 2009 27/