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Benefits

The GEOCLIP u-bend pipe separator is designed to optimize vertical heat exchanger (VHE) performance both reducing costs and easing installation. more»

Research

Research performed at independent testing facilities shows the GEOCLIP maximizes heat transfer by providing optimal positioning of the u-bend within the borehole. more»

Installation

Installation is quick and easy: the GEOCLIP simply snaps onto the u-bend and tremie pipes locking the assembly into the smallest configuration possible for ease in borehole insertion. more»

GEOCLIP placement is recommended every 10 feet of linear borehole.

GEOCLIP

GEOCLIP® U-Bend Pipe Separator

The GEOCLIP is a u-bend pipe separator, developed in 1999, by GBT, Inc. It utilizes geothermal technology and is designed to enhance vertical heat exchanger (VHE) performance, improving energy efficiency or heat transfer from 20-35%.

The GEOCLIP decreases borehole resistance, thereby significantly increasing the performance of a VHE and lowering the installation costs by shortening required VHE lengths.

About Typical Standard VHE Installations: A standard VHE installation has the two pipes that make up the u-bend pipe assembly either touching or in close proximity to each other. This type of assembly is less than optimal because the two pipes interfere with each others’ ability to exchange energy with the earth.

These u-bend pipes are usually encased with a 20% solids or thermally enhanced bentonite grout (often required by State regulations) in order to seal the borehole to prevent contamination of water aquifers below ground. Although the bentonite grout mixture is excellent for sealing the borehole, it has poor heat transfer characteristics in relation to surrounding soil or rock and acts as an insulator restricting energy exchange between the u-bend pipes and the surrounding soil.

To address this inefficiency, recent technology advances have yielded the design of the GEOCLIP u-bend pipe separator.

GEOCLIP displaces 50 lbs. of thermally enhanced silica sand.

How it Works

How it Works

The GEOCLIP® is used to position the u-bend pipes of a vertical heat exchanger at the borehole wall. It is designed to separate the pipes as far apart as possible to achieve the highest heat transfer rate possible for that location, pipe size, grouting material, borehole size and depth.

Challenges of standard VHE installation:

  1. Low Thermal Conductivity Grout: Most state regulations require using a bentonite-based grout to seal the borehole. This backfill has a 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.
  2. U-Bend Pipe Energy Interaction: In a standard installation, the u-bend pipes are often close to each other or even touching each other at certain points 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 (VHE) depths to be longer than necessary.


The GEOCLIP lessens the insulating effects of bentonite-based grouts and u-bend pipe energy interaction:

Comparison

This diagram shows a typical vertical heat exchanger (VHE) installation on the left compared to a GEOCLIP installation on the right.


The GEOCLIP installation:

  • Positions the pipe next to the borehole wall eliminating the insulating effects of the backfill grout.

  • 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 typical installation.

FAQ

What is a GEOCLIP?

A GEOCLIP is a u-bend pipe separator designed to enhance vertical heat exchanger performance by ensuring consistent, optimum placement within the borehole.

How do GEOCLIPS work?

GEOCLIPS provide maximum separation of the two VHE pipes from each other and force them against the sides of the borehole. This maximizes the exposure to the earth for heat transfer, eliminates the insulating effects of bentonite-based grouts, and ensures consistent placement of the pipes throughout the borehole.

What are the benefits of using GEOCLIPS on a geothermal installation?

The use of GEOCLIPS can improve the efficiency (heat transfer) of the installation by 20% - 35% for optimal performance and reduced energy costs, making the most of the geothermal investment.

Why should I use GEOCLIPS?

The increased efficiency GEOCLIPS provide can allow for shortened required VHE lengths and reduce the need for thermally enhanced grouts therefore decreasing installation costs.

Will the benefit of the GEOCLIPS be greater if they are placed closer than 10 ft?

There is a negligible gain for placing additional GEOCLIPS; 10 ft. has proven to be the optimal distance for performance.

Is the spring tension on the GEOCLIP strong enough to force the pipes within the borehole once there's grout around it?

Yes, the force of the GEOCLIP was designed for the recommended pipe sizes within a maximum recommended borehole diameter of 8".

Is it cheaper to add GEOCLIPs and eliminate borehole depth?

Yes, the cost of additional borehole length far exceeds the cost of GEOCLIPS.

Doesn't it take more time to install using GEOCLIPS?

It takes about 10 seconds per GEOCLIP. So on a 200 ft. borehole, it would add an average of 3 minutes conservatively. Keep in mind for each GEOCLIP you can eliminate 50 lbs. of thermally enhanced silica sand.

What are the minimum required borehole diameters?

For specific information reference the GEOCLIP Required Borehole Diameter Chart.

Benefits

Benefits

The GEOCLIP® u-bend pipe separator is designed to optimize vertical heat exchanger (VHE) performance in both residential and commercial geothermal wellfield installations, reducing costs and making installation easier in a number of ways.


Increases Heat Transfer by 20-35%

By separating the u-bend pipes as far as possible within the borehole, the GEOCLIP reduces energy exchange interference between the two pipes. This pipe positioning provides superior heat transfer characteristics compared to a typical VHE installation.

Expands System Capacity

Superior heat transfer characteristics, provided by the optimal u-bend pipe positioning within the borehole, expands the system capacity without drilling additional boreholes.

Reduces Installation Costs

The GEOCLIP decreases borehole resistance, thereby reducing installation costs by shortening required VHE design lengths. Each GEOCLIP replaces approximately 50 lbs. of thermally-enhanced silica sand to achieve an equivalent heat transfer rate, eliminating the hassle of handling and saving installation time.

Increased Efficiency and Reduced Energy Costs

The spring mechanism of the GEOCLIP places the pipe next to the borehole wall, eliminating the insulating effects of the bentonite grout on the u-bend pipes and maximizing the interaction with the earth for the exchange of energy. This also provides for a more efficient system performance and reduced energy costs.

Research

Field-Proven and Independently Tested

Research performed by GBT, Inc., and independent universities indicates that positioning u-bend pipes at the borehole wall directly across from one another, significantly increases the heat transfer rate of the vertical heat exchanger (VHE) over a standard installation, regardless of the backfill or grouting material used. Studies indicate that utilizing the GEOCLIP® is the most effective installation method designed to reduce required borehole lengths leading to a reduction in vertical installation costs.


The GEOCLIP decreases borehole resistance, thereby significantly increasing the performance of a VHE and lowering the installation costs by shortening required VHE lengths.


Geothermal Borehole Resistance

A standard VHE installation has the two pipes that make up the u-bend pipe assembly that are either touching or are in close proximity of each other, thus interfering with each other’s ability to exchange energy with the earth.


These u-bend pipes are usually encased with a 20% or thermally enhanced solids bentonite grout (often required by State regulations) in order to seal the borehole to prevent contamination of water aquifers below ground. Although the bentonite grout mixture is excellent for sealing the borehole in relation to the surrounding soil or rock, it has poor heat transfer characteristics and acts as an insulator restricting energy exchange between the u-bend pipes and the surrounding soil.


This diagram illustrates how the energy flux of a VHE is affected by its configuration.

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Standard U-Bend Installation

The first configuration has a standard u-bend installation where the pipe placement, at its best, is evenly spaced in the borehole and the borehole is sealed with a standard bentonite grout. This installation has difficulty exchanging energy with the earth because:


  • It is surrounded in insulation (bentonite grout).
  • The energy interference between the two u-bend pipes (which are too close together).

GEOCLIP U-Bend Installation

The second 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 bentonite grout. This means there is:


  • No difficulty in exchanging energy with the earth, regardless of the backfill or bentonite grout used.
  • Lessens insulating effects of the bentonite grout on the u-bend pipes, because the pipes are at the borehole wall.
  • Low energy interference between the u-bend pipes, because they are as far apart as possible within the borehole.


The first configuration uses no performance-enhancing technology; therefore, the borehole resistance greatly inhibits the exchange of energy of the circulating fluid and the earth. The energy flux increases significantly with the use of u-bend pipe separators in the second configuration. A key point to consider is that there is a balance between the added cost of increasing VHE performance and the savings incurred by shortening the total VHE length.



Bore Thermal Conductivity Comparison Graph

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This graph illustrates the results from a thermal conductivity test performed by Oklahoma State University. This test verifies that there is a substantial increase in the heat transfer rate with GEOCLIP installation when compared to typical installations.

Installation

The GEOCLIP® easily snaps onto the u-bend and tremie pipes locking the assembly into the smallest configuration possible for ease in borehole insertion.

  • GEOCLIPS are fastened to the u-bend and tremie pipe assembly at 10’ intervals during u-bend insertion. After the pipes are “snapped” into the GEOCLIP, the retaining clip should be removed.
  • Once the u-bend and tremie assembly is inserted to its desired depth, grout is pumped through the tremie pipe.
  • During the grouting procedure, the tremie pipe is pulled out of the borehole which then releases the spring-activated GEOCLIPs.
  • The GEOCLIP pushes the u-bend pipes to the borehole wall positioning the pipes directly across from one another.

Please download the Installation Instructions for more detailed directions and instructional photos.