WO2012051338A1

WO2012051338A1 - Systems and methods for installing geothermal energy transfer loops

Info

Publication number: WO2012051338A1
Application number: PCT/US2011/056013
Authority: WO
Inventors: Randy R. Runquist; Keith Allen Hoelting
Original assignee: Vermeer Manufacturing Company
Priority date: 2010-10-12
Filing date: 2011-10-12
Publication date: 2012-04-19

Abstract

The present disclosure relates to a system for installing an energy transfer loop in a bore. The energy transfer loop includes first and second geothermal exchange pipe sections interconnected by a U-shaped portion that couples the first geothermal exchange pipe section in fluid communication with the second geothermal exchange pipe section. The system includes the system an energy transfer loop carrier structure for directing the energy transfer loop downwardly into the bore. The system also includes an energy transfer loop support member that is connected to the energy transfer loop carrier structure. The energy transfer loop support member including a leg that projects laterally outwardly from the energy transfer loop carrier structure and that fits between the first and second geothermal exchange pipe sections adjacent to the U-shaped portion of the energy transfer loop. The system further includes a cover having a shaped distal nose and an open proximal end. The U-shaped portion of the energy transfer loop and the energy transfer loop support member can be inserted into the cover through the open proximal end of the cover.

Description

SYSTEMS AND METHODS FOR INSTALLING

GEOTHERMAL ENERGY TRANSFER LOOPS

TECHNICAL FIELD

The present disclosure relates generally to systems and methods for installing underground product. More particularly, the present disclosure relates to systems and methods for installing geothermal energy transfer loops.

BACKGROUND

Geothermal heat pump systems are increasingly being used to heat and cool residential and commercial buildings. Geothermal heat pump systems are configured to take advantage of the difference in temperature between the ambient air and the earth by transferring heat to and from the earth to provide an

environmentally friendly and cost effective means for heating and cooling buildings.

A typical geothermal heat pump system can include a plurality of geothermal energy transfer loops that are installed underground. Such geothermal energy transfer loops can be installed horizontally, vertically or at an angle. By pumping an energy transfer fluid through the geothermal energy transfer loops, energy can readily be transferred between the geothermal heat pump system and the earth in which the geothermal energy transfer loops have been installed. In conditions where the ambient air temperature is warmer than the earth in which the geothermal energy transfer loops have been installed, heat is transferred from the geothermal energy transfer loops to the earth thereby cooling the energy transfer fluid being pumped through the geothermal energy transfer loops. Energy transfer fluid cooled in this way can be used for the effective cooling of a building. In contrast, in cold weather conditions in which the ambient air is cooler than the temperature of the earth in which the geothermal energy transfer loops have been installed, heat is transferred from the earth to the energy transfer fluid being pumped through the geothermal energy transfer loops. In this way, heat drawn from the earth can readily be used for heating a building.

Installing geothermal energy loops in underground applications can be time consuming and expensive. More efficient and cost effective methods and systems for installing underground geothermal energy transfer loops are needed. SUMMARY

One aspect of the present disclosure relates to methods and systems for efficiently installing geothermal energy transfer loops.

Another aspect of the present disclosure relates to systems and methods for installing geothermal energy transfer loops in bores whereby covers are used to facilitate directing the geothermal transfer energy loops into the bores. In certain embodiments, the covers allow U-shaped portions of the geothermal energy transfer loops and lower-most end portions of energy transfer loop carrier structures to be guided together as units through the bores.

A further aspect of the present disclosure relates to a cover for use in installing a geothermal energy transfer loop with an energy transfer loop carrier structure.

Examples representative of a variety of inventive aspects are set forth in the description that follows. The inventive aspects relate to individual features as well as combinations of features. It is to be understood that both the foregoing general description and the following detailed description merely provide examples of how the inventive aspects may be put into practice, and are not intended to limit the broad spirit and scope of the inventive aspects.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. la shows a system in accordance with the principles of the present disclosure, the system is shown drilling a bore;

FIG. lb shows the system of FIG. lb with a drill string of the system being withdrawn from the bore;

FIG. lc shows the system of FIG la with the drill string equipped with an arrangement adapted for facilitating the installation of geothermal energy transfer loops, the system is shown in the process of installing a geothermal energy transfer loop in the bore;

FIG. Id shows a rail and drive unit of the drilling machine of the system of FIGS, la-lc;

FIG. 2 is a partially exploded view of the arrangement of FIG. 1 c adapted for facilitating the installation of geothermal energy transfer loops; FIG. 3 is another view of the arrangement of FIG. 2 showing an energy transfer loop carrier structure being retracted upwardly from a covered end of the geothermal energy transfer loop;

FIG. 4 is a perspective view of an end rod of the arrangement of FIGS. 2 and 3;

FIG. 5 is a proximal end view of the end rod of FIG. 4;

FIG. 6 is a distal end view of the end rod of FIG. 4;

FIG. 7 is a cross-sectional view taken along section lines 7-7 of FIG. 6; FIG. 8 is a perspective view of an energy transfer loop support member of the arrangement of FIGS. 2 and 3;

FIG. 9 is a distal end view of the energy transfer loop support member of

FIG. 8;

FIG. 10 is a side view of the energy transfer loop support member of FIG. 8; FIG. 11 is a proximal end view of the energy transfer loop support member of FIG. 8;

FIG. 12 is a cross-sectional view taken along section line 12-12 of FIG. 1;

FIG. 13 is a perspective view of another arrangement in accordance with the principles of the present disclosure for installing geothermal energy transfer loops;

FIG. 14 is an assembled view of the arrangement of FIG. 13;

FIG. 15 is a cross-sectional view taken along section line 15-15 of FIG. 14;

FIG. 16 is a distal end view of another arrangement in accordance with the principles of the present disclosure for installing geothermal energy transfer loops;

FIG. 17 is a cross-sectional view taken along section line 17-17 of Fig. 16;

FIG. 18 is a cross-sectional view of still another arrangement in accordance with the principles of the present disclosure for installing geothermal energy transfer loops;

FIG. 19 is a perspective view of another arrangement in accordance with the principles of the present disclosure for installing geothermal energy transfer loops;

FIG. 20 is a side view of the arrangement of FIG. 19 with a cover of the arrangement shown in phantom so that the interior volume of the cover can be viewed;

FIG. 21 is a top view of the arrangement of FIG. 19 with the cover shown in cross-section;

FIG. 22 is a fragmentary isometric view of the arrangement of FIG. 19; FIG. 23 is an isometric view of a first axial end of the cover of the arrangement of FIG. 19 with a first sidewall of the cover shown in an open position;

FIG. 24 is an isometric view of the second axial end of the cover of the arrangement of FIG. 19 with the first sidewall in the open position;

FIG. 25 is an end view of a second axial end of the cover of the arrangement of FIG. 19.

DETAILED DESCRIPTION

The present disclosure relates to systems and methods for installing geothermal energy transfer loops in the ground. An example geothermal energy transfer loop 12 is shown at FIG. 2. The geothermal energy transfer loop 12 includes first and second geothermal exchange pipe sections 56 and 58

interconnected by a U-shaped portion 60 that couples the first geothermal exchange pipe section 56 in fluid communication with the second geothermal exchange pipe section 58. For typical applications, the first and second geothermal exchange pipe sections 56, 58 can have outer diameters ranging from about 1 inch to about 1.7 inches. Of course, other sizes could be used as well. In certain embodiments, the U- shaped portion 60 can comprise a U-shaped fitting bonded, fused or otherwise connected to the first and second geothermal exchange pipe sections 56 and 58. Example U-shaped fittings are disclosed at United States Design Patent Nos.

D498,771 and D501 ,915, that are hereby incorporated by reference in their entireties. It will be appreciated that the phrase "U-shaped portion" means any structure for reversing a direction of fluid flow.

Typically, geothermal energy transfer loops are pre-spooled at a factory in predetermined lengths (e.g., 100 to 1,000 feet). An example spool 18 is shown at FIG lc. Coiling the geothermal energy transfer loops on spools facilitates transporting the geothermal energy transfer loops to desired installation sites and also facilitates installing the geothermal energy transfer loops in the ground. In practice, a plurality of spools each supporting a desired footage of geothermal energy transfer loop are shipped to an installation site. At the installation site, bores are formed in the ground. The bores are formed having lengths/depths

corresponding to the lengths of the geothermal energy transfer loops coiled on the spools. After the bores are formed, the geothermal energy transfer loops are installed in the bores. The geothermal energy transfer loops are gradually paid off the spools as the geothermal energy transfer loops are installed in the bores.

FIG. la is a schematic view showing a drilling system 10 for drilling bores 14 in which geothermal energy transfer loops can be installed. The system 10 includes a drilling machine 16 having a chassis 20 supported on a propulsion structure such as a plurality of tracks 22. A rail 24 is pivotally connected to the chassis 20 at a pivot axis 26. The rail 24 can be pivoted about the pivot axis 26 relative to the chassis 20 between a vertical position (as shown at FIG. la) and a horizontal position (not shown). The guide rail 24 can also be set at angled orientations between the horizontal and vertical positions. The ability to change angle the guide rail 24 relative to the ground allows the drilling machine 16 to form vertical bores, horizontal bores or angled bores. The ability to angle the guide rails 24 also facilitates installing geothermal transfer loops in horizontal bores, vertical bores or angled bores.

Still referring to FIG. la, the drilling machine 16 includes a drive unit 28 mounted on the rail 24. The drive unit 28 includes a linear drive 30 (see FIG Id) for moving the drive unit 28 longitudinally back and forth along the length of the guide rail 24. As shown at FIG. lc, the linear drive 30 includes a rack and pinion drive. However, alternative drive systems such as drive cylinders (e.g., hydraulic or pneumatic cylinder), chain drives or other arrangements can also be used. Linear movement of the drive unit 28 allows the drive unit 28 to be used to push a drill string into the ground and to withdraw a drill string from the ground. The drive unit 28 also includes a rotational driver 36 used to rotate a drill string about a central longitudinal axis of the drill string. Further details about the drilling machine 16 are provided in United States Provisional Patent Application Serial No. 61/295,535, that is hereby incorporated by reference in its entirety.

As described herein, the bore 14 is formed through a drilling process.

However, it will be appreciated that the term "bore" includes any opening formed in the ground regardless of the process by which it is formed.

To install a geothermal energy transfer loop, the drilling machine 16 is initially used to form the bore 14. For example, as shown at FIG. la, the drilling machine 16 is used to force a drill string 33 into the ground thereby forming the bore 14. In certain embodiments, the drill string includes a plurality of drill rods 35 that are strung together to form the drill string 33. During drilling operations, a drill head 37 including cutting structures (e.g., teeth, blades, edges, other structures) is mounted at a distal end of the drill string 33. The linear drive 30 of the drilling machine 16 is used to thrust the drill string 33 into the ground while the rotational drive 36 concurrently causes the drill string 33 to rotate about a central longitudinal axis 40 of the drill string 33 thereby causing the drill head to rotate in a cutting motion. It will be appreciated that the bore 14 can comprise a vertical bore, a horizontal bore, or an inclined bore.

After the bore 14 has been drilled to a desired length/depth, the drilling machine 16 is used to retract the drill string from the bore 14 (see FIG. lb). Once the drill string 33 has been fully retracted, the drill head 37 is removed and replaced an energy transfer loop installation tool 50 (see FIG. lc). The energy transfer loop installation tool 50 includes an end rod 52 that mounts to the distal end of the drill string 33 and that coaxially aligns with the drill string 33. The energy transfer loop installation tool 50 also includes an energy transfer loop support member 54 (see FIGS. 2 and 3) that projects laterally outwardly from the central longitudinal axis 40 of the drill string 33. The drilling machine 16, equipped with the energy transfer loop installation tool 50, is preferably used to move, force, or otherwise direct the geothermal energy transfer loop 12 into the bore 14. It will be appreciated that the bore 14 can be a vertical bore, a horizontal bore or an angled bore. In one embodiment, a portion of the energy transfer loop support member 54 is positioned between the first and second geothermal energy pipe sections 56, 58 adjacent to the U-shaped portion 60.

To move the geothermal energy transfer loop 12 into the bore 14, the drive unit 28 of the drilling machine 16 is used to force the drill string 33 into the bore 14 as the drive unit 28 is moved in a first direction 32 by the linear drive 30. The force in the first direction 32 provided by the drilling machine 16 is transferred from the drill string 33 to the geothermal energy transfer loop 12 by the energy transfer loop support member 54. Specifically, because the energy transfer loop support member 54 is positioned between the first and second geothermal exchange pipe sections 56, 58 adjacent to the U-shaped portion 60, movement of the drill string in the first direction 32 brings the energy transfer loop support member 54 into contact with the U-shaped portion 60 thereby forcing the U-shaped portion 60 into the bore 14 in the first direction 32. As the U-shaped portion 60 is forced in the first direction 32, the first and second geothermal exchange pipe section 56, 58 are pulled in the first direction 32 into the bore 14 behind the U-shaped portion 60. As the first and second geothermal exchange pipe sections 56, 58 are moved in the first direction 32 into the bore 14, the spool 18 turns about its central axis thereby allowing the first and second geothermal exchange pipe sections 56, 58 to be paid off from the spool 18.

To aid in manipulation/directing the geothermal energy transfer loop 12 into the bore 14 in concert with the drill string 33 and the energy transfer loop installation tool 50, a cover 62 can be placed over the U-shaped portion 60 of the geothermal energy transfer loop 12 and also over a distal most end of the energy transfer loop installation tool 50. The cover 62 can have a shaped (e.g., tapered, rounded) lower end 152 forming a nose adapted for guiding the cover 62 down the bore 14. The cover 62 assists in integrating the lower end of the geothermal energy transfer loop 12 with the energy transfer loop installation tool 50 such that the energy transfer loop installation 50 and the lower end of the geothermal energy transfer loop 12 are moved together as an integrated unit.

During direction of the geothermal energy transfer loop 12 into the bore 14, drill rods 35 are progressively added to the drill string to increase the length of the drill string. The rods 35 are progressively added until the geothermal energy transfer loop 12 has been moved to the desired depth within the bore 14. Once the geothermal energy transfer loop 12 has reached the desired depth in the bore 14, the drill string 33 is retracted from the bore 14 while the geothermal energy transfer loop 12 and the cover 62 remain positioned within the bore 14. Retraction of the drill string 33 causes the energy transfer loop installation tool 50 to be pulled from inside the cover 62 and to be disengaged from the geothermal energy transfer loop 12. The individual drill rods 35 of the drill string 33 are progressively removed from the bore 14 by the drive unit 28 as part of the retraction process.

Referring to FIGS. 4-7, the end rod 52 of the energy transfer loop installation tool 50 is adapted to connect to a distal end of the drill string (e.g., by a threaded connection). The end rod 52 includes a distal end 70 and an opposite proximal end 72. The proximal end 72 includes internal threads 73 for facilitating connecting the end rod 52 to the distal end of the drill string 33. The distal end 70 is configured for rotatably mounting the energy transfer loop support member 54 to the end rod 52 such that the end rod 52 can rotate about the central longitudinal axis 40 of the drill string relative to the energy transfer loop support member 54. As shown at FIG. 2, a cylindrical sleeve 74 of the energy transfer loop support member 54 fits over a cylindrical bearing structure 76 which is integral with the distal end 70 of the end rod 52. The cylindrical sleeve 74 includes a proximal end 78 that abuts against a shoulder 80 of the end rod 52. The cylindrical sleeve 74 also includes a distal end 82 that receives a retention cap 84 that assists in retaining the cylindrical sleeve 74 on the distal end 70 of the end rod 52. A fastener 86 extends through the retention cap 84 and the sleeve 74 and engages the distal end 70 of the end rod 52. In the depicted embodiment, the fastener 86 is shown as a cap screw that threads into an internally threaded opening 88 defined within the bearing structure 76 of the end rod 52.

Referring back to FIGS. 4-7, the end rod 52 includes a distal portion 90 positioned adjacent the distal end 70, a proximal portion 92 positioned adjacent the proximal end 72 and an intermediate portion 94 positioned between the distal and proximal portions 90, 92. The proximal portion 92 has an outer diameter Dj that generally matches the outer diameter of the drill string 33. The distal portion 90 has an outer diameter D₂ that is smaller than the outer diameter Dj. The intermediate portion 94 has an outer diameter D₃ that gradually transitions from the diameter Di to the diameter D₂. A drilling fluid discharge port 96 is defined at the intermediate portion 94. The drilling fluid discharge port 96 is in fluid communication with a fluid passage 98 that extends from the drilling fluid discharge port 96 through the intermediate and proximal portions 94, 92 to the proximal end 72 of the end rod 52. When the end rod 52 is coupled to the distal end of the drill string, the fluid passage 98 is in fluid communication with a central passage of the drill string 33 that allows drilling fluid to be pumped from an above-ground source of drilling fluid through the drill string 33 to the drilling fluid discharge port 96. A source of drilling fluid 100 and a pump 102 for pumping the drilling fluid down the drill string are schematically shown at FIG. Id.

When the cover 62 is mounted over the U-shaped portion 60 and the distal most end of the energy transfer loop installation tool 50, a proximal/upper end 154 of the cover 62 is distally offset from the drilling fluid discharge port 96.

Additionally, since the drilling fluid discharge port 96 is defined through the tapered intermediate portion 94, the drilling fluid discharge port 96 is adapted to direct a stream of drilling fluid outwardly from the end rod 52 at an angle Θ relative to the central longitudinal axis 40 of the drill string. The positioning of the cover 62 offset from the drilling fluid discharge port 96 combined with the angling of the drilling fluid stream prevents fluid from being sprayed directly into the cover 62. This is advantageous because spraying the stream of drilling fluid into the cover 62 could cause the cover to be unintentionally forced off of the U-shaped portion 60 of the geothermal energy transfer loop 12 and the distal most end of the energy transfer loop installation tool 50 prior to reaching the end of the bore 14.

The drilling fluid discharge port 96 is provided to assist in clearing debris or other obstructions from the side wall of the bore 14 during installation of the geothermal energy transfer loop 12 with the energy transfer loop installation tool 50. Rotation of the drill string 33 by the rotational drive 36 during installation of the geothermal energy transfer loop 12 causes the end rod 52 to be rotated about the central longitudinal axis 40 of the drill string which causes the drilling fluid discharge port 96 to rotate about the central longitudinal axis 40. In this way, the spray direction of the drilling fluid discharge port 96 can be rotated 360 degrees about the inside of the bore 14 to assist in clearing obstructions.

FIGS. 8-11 provide various views of the energy transfer loop support member 54 of the energy transfer loop installation tool 50. As shown in such figures, the cylindrical sleeve 74 of the energy transfer loop support member 54 defines a central opening 120 for receiving the bearing structure 76 at the distal end 70 of the end rod 52. The central opening 120 extends through the cylindrical sleeve 74 from the proximal end 78 to the distal end 82 of the sleeve 74. The central opening 120 has cylindrical shape that allows relative rotation between the sleeve 74 and the bearing structure 76.

Referring still to FIGS. 8-11, the energy transfer loop support member 54 also includes a leg 122 that projects laterally/outwardly from the cylindrical sleeve 74. The leg 122 also projects radially outwardly from the central longitudinal axis 40 of the drill string. The leg 122 has a first side 124 that faces in a direction 125 and a second side 126 that faces in a direction 127 that is opposite from the direction 125. The energy transfer loop support member 54 also includes a flange 128 positioned at an outer end of the leg 122. The flange includes a first extension 130 that extends outwardly in the direction 125 from the leg 122 and cooperates with the first side 124 of the leg to define a first open-sided pocket 132. The flange 128 also includes a second extension 134 that extends outwardly in the direction 127 from the leg 122 and cooperates with the second side 126 of the leg 122 to define a second open-sided pocket 136. The directions 125, 127 are generally perpendicular to a plane P that extends through the leg 122 and that includes the central longitudinal axis 40 of the drill string and the center axis of the sleeve 74. During installation of the geothermal energy transfer loop 12, the leg 122 is positioned between the first and second geothermal exchange pipe sections 56, 58 adjacent to the U-shaped portion 60.

As shown at FIG. 12, when the leg 122 is positioned between the first and second geothermal exchange pipe sections 56, 58 during installation of the geothermal energy transfer loop 12, the first geothermal exchange pipe section 56 is positioned within the first open-sided pocket 132 and the second geothermal exchange pipe section 58 is positioned within the second open-sided pocket 136. As so positioned, the first and second geothermal exchange pipe sections 56, 58 respectively engage the first and second sides 124, 126 of the leg 122, and a distal end of the leg 122 engages a proximal portion of the U-shaped portion 60 of the geothermal energy transfer loop 12. Thus, when the drill string 33 is forced down the bore 14 during installation of the geothermal energy transfer loop, the leg 122 is positioned to transfer force from the drill string to the proximal portion of the U- shaped portion 60. Such transferred force causes the geothermal energy transfer loop to be moved in to the bore in concert with the movement of the drill string 33.

Referring to FIG. 12, an outermost end of the flange 128 has a surface 140 that extends along a curvature defined by a radius R_\. The radius Rj is larger than a radius R₂ which defines the outer diameters of the first and second geothermal exchange pipe sections 56, 58.

Referring to FIG. 2, the cover 62 has an interior volume configured for receiving the U-shaped portion 60 of the geothermal energy transfer loop 12 and a distal-most end of the energy transfer loop installation tool 50. At least a portion of the energy transfer loop support member 54 is also received within the interior volume of the cover 62. The cover 62 defines a central longitudinal axis 151 that extends along a length of the cover 62 from the lower end 152 to the upper end 154. The upper end 154 of the cover 62 is open while the lower end 152 is rounded and closed. The cover 62 is preferably sufficiently long to also cover end portions of the first and second geothermal exchange pipe sections 56, 58. The cover 62 has a side wall 156 that surrounds the interior volume and extends between the upper and lower ends 154, 152 of the cover 62. The side wall 156 defines a hollow, generally triangular inner shape when viewed in cross-section taken along a plane

perpendicular to the central longitudinal axis 151 (see FIG. 12). The generally triangular inner shape has rounded corners.

In certain embodiments, the rounded corners of the generally triangular inner shape extend along curvatures each having a radius of curvature that corresponds to the radii of curvatures R₂ defining the outer diameters of the first and second geothermal exchange pipe sections 56, 58. Thus, the cover 62 has a shape that is contoured to match or conform to the outer shapes of the geothermal exchange pipe sections 56, 58. The shape of the cover 62 also conforms to the outer shape of the distal end 70 of the end rod 52. In one embodiment, the radii of curvatures R₂ defining the rounded corners of the generally triangular shape are in the range of .50-1.0 inches. In other embodiments, the generally triangular inner shape has a maximum cross-dimension CD that is less than 4.5 inches.

Referring again to FIG. 12, a generally triangular shape of the cover 62 has a first side 160, a second side 162 and a third side 164. The first side 160 extends from a first rounded corner 168 generally matching the curvature of the first geothermal exchange pipe section 56 to a second rounded corner 170 generally matching the curvature of the distal end 70 of the end rod 52. The second side 162 extends from a third rounded corner 172 generally matching the curvature of the second geothermal exchange pipe section 58 to the second rounded corner 170. The third side 164 extends between the first and third rounded corners 168, 172. The first and second sides 160, 162 are generally straight. In contrast, the third side 164 has a curvature that matches/conforms to the curvature of the outer surface of the flange 128. The radius of curvature along which the curved portion of the third side 164 extends is larger than the radii of curvatures R₂ defining the rounded corners of the generally triangular shape. It will be appreciated that the curved portions of the generally triangular shape include inner surfaces defining concave curvatures and outer surfaces defining convex curvatures.

In a preferred embodiment, both the energy transfer loop support 54 and the cover 62 are made of a plastic material. In certain embodiments, the cover 62 is made of a plastic material having a wall thickness in the range of .03 to .07 inches.

Figures 13-15 show an alternative system for installing a geothermal energy transfer loop. The depicted system includes a U-shaped portion 60' formed as a plastic fitting having a shaped/contoured nose. The depicted system also includes a cover 62' having a portion shaped to conform to the shaped/contoured nose of the fitting. The depicted system further includes an energy transfer loop support member 54' similar to the support member 54 except a leg 122' of the support member 54' does not include an end flange.

Figs. 16 and 17 show still another system in accordance with the principles of the present disclosure for installing a geothermal energy transfer loop 12. The system includes an end rod 252 adapted to connect to a distal end of a drill string (e.g., by a threaded connection). The end rod 252 includes a main body 253 having a distal end 270 and an opposite proximal end 272. The proximal end 272 includes internal threads 273 for facilitating connecting the end rod 252 to the distal end of the drill string 33. The end rod 252 also includes a distal extension 275 that is coaxially aligned with the main body 253 and that extends distally outwardly from the distal end 270 of the main body 253. In the depicted embodiment, the distal extension 275 is connected to the distal end 270 of the main body 253 by a threaded connection 277. The main body 253 and the distal extension 275 cooperate to define a fluid passage 298 that extends longitudinally through the end rod 252 from the proximal end 272 of the main body 253 to a distal end 279 of the distal extension

275. When the end rod 252 is coupled to the distal end of the drill string 33, the fluid passage 298 is in fluid communication with a central passage of the drill string 33 that allows drilling fluid to be pumped from an above-ground source of drilling fluid through the drill string 33 to a discharge port 296 located at the distal end 279 of the distal extension 275.

Referring to Fig. 17, a cylindrical sleeve 274 of an energy transfer loop support member 254 fits over a cylindrical bearing structure 276 defined by the distal extension 275. The cylindrical sleeve 274 is captured between the distal end

270 of the main body 253 and a shoulder 281 provided on the distal extension 275.

The cylindrical sleeve 274 is free to be rotated about the cylindrical bearing structure

276. As shown at Fig. 17, the energy transfer loop support member 254 also includes a leg 222 that projects outwardly from the cylindrical sleeve 274 and is adapted to engage the U-shaped portion 60 of the geothermal energy transfer loop 12 during installation of the geothermal energy transfer loop 12.

Referring still to Fig. 17, the system further includes a cover 262 that receives the U-shaped portion 60 of the energy transfer loop 12, the distal extension

275 and the energy transfer loop support member 254. The cover 262 defines an opening 290 that is coaxially aligned with the end rod 252. In the depicted embodiment, the opening 290 is defined through a rounded distal end of the cover 262 and receives the distal end 279 of the distal extension 275. In this way, fluid discharged through the drilling fluid discharge port 296 can be used to clear material in the bore located distally with respect to the distal end of the cover 262. In the depicted embodiment, the distal end 279 of the distal extension 275 projects distally through the opening provided in the cover 262. In alternative embodiments, the distal end 279 of the distal extension 275 may be flush with the opening 290 or may be slightly proximally recessed relative to the opening 290.

Fig. 18 shows the end rod 252 equipped with a one-way check valve 292 at the distal end of the distal extension 275. The one-way check valve allows drilling fluid to be discharged distally through the drilling fluid discharge port 296 at the distal end of the distal extension 275, but prevents material within the bore from flowing proximally into the fluid passage 298.

Referring now to Figs. 19 and 20, an alternative system for installing a geothermal energy transfer loop 12 is shown. The system includes an end rod 352 adapted to connect to a distal end of a drill string (e.g., by a threaded connection). The end rod 352 includes a main body 353 having a distal end 370 and an opposite proximal end 372. The proximal end 372 includes internal threads for facilitating connecting the end rod 352 to the distal end of the drill string 33. The end rod 352 also includes a distal extension 375 that is coaxially aligned with the main body 353 and that extends distally outwardly from the distal end 370 of the main body 353. In the depicted embodiment, the distal extension 375 has an outer diameter that is less than an outer diameter of the main body 353. A shoulder 380 is formed between the distal end 370 of the main body 353 and the distal extension 375.

Referring now to Figs. 19 and 21-23, the system further includes a U-shaped portion 360 of the energy transfer loop 12. The depicted embodiment, the U-shaped portion 360 is formed as a plastic fitting. The U-shaped portion 360 includes a first end portion 400 and a second end portion 402. The first end 400 is adapted to receive one of the first and second geothermal exchange pipe sections 56, 58 while the second end 402 is adapted to receive the other of the first and second geothermal exchange pipe sections 56, 58. The U-shaped portion 360 further includes a shaped/contoured nose 361 that extends outwardly in a direction that is opposite of the direction the first and second geothermal exchange pipe sections 56, 58 extend outwardly from the U-shaped portion 360. In the depicted embodiment, a width of the contoured nose 361 decreases as the contoured nose 361 extends outwardly from the U-shaped portion 360.

Referring now to Figs. 19, 20, 24 and 25, the system further includes a cover 362. The cover 362 includes a body 404 having a first axial end 406 and an oppositely disposed second axial end 408. The body 404 defines an interior volume 410. The first axial end 406 of the body 404 defines an opening through which the interior volume 410 can be accessed. The interior volume 410 of the cover 362 is adapted to receive at least a portion of the U-shaped portion 360 and at least a portion of the end rod 352. In the depicted embodiment, the width of the interior volume 410 decreases from the first axial end 406 to the second axial end 408.

The body 404 includes a plurality of sidewalls 412. In the depicted embodiment, the sidewalls 412 include a taper portion 414 disposed adjacent to the second axial end 408. The plurality of sidewalls 412 includes a first sidewall 412a and an oppositely disposed second sidewall 412b. In the depicted embodiment, the first and second sidewalls 412a, 412b are generally parallel.

The first sidewall 412a defines a first slot 416. The second sidewall 412b defines a second slot 418. In the depicted embodiment, a length of each of the first and second slots 416, 418 is less than a length of the first and second sidewalls, respectively. In the depicted embodiment, the first slot 416 includes a first end wall 420 while the second slot 418 includes a second end wall 422.

The body 404 further defines an opening 424 that extends through a portion of the second sidewall 412b and the second axial end 408. The opening 424 allows the distal extension 375 of the end rod 352 to pass through the cover 362.

The system further includes an energy transfer loop support member 354.

The energy transfer loop support member 354 includes a cylindrical sleeve 374. The cylindrical sleeve 374 defines a bore 425 that is adapted to receive the distal extension 375 of the end rod 352. The cylindrical sleeve 374 includes a proximal end 378 that abuts against the shoulder 380 of the end rod 352. The cylindrical sleeve 374 also includes a distal end 382 that abuts against the second end wall 422 of the second slot 418 of the cover 362.

The energy transfer loop support member 354 further includes a leg 426. The leg 426 extends outwardly from the cylindrical sleeve 374 in a generally radial direction. The leg 426 includes a distal end 428 that abuts against the first end wall 420 of the first slot 416.

Referring now to Figs. 19-25, the assembly of the system will be described. In the depicted embodiment, the distal end 382 of the energy transfer loop support member 354 is engaged to the slot 418 of the second sidewall 412b of the cover 362. In one embodiment, the energy transfer loop support member 354 is welded to the second sidewall 412b. The energy transfer loop support member 354 is positioned so that the leg 426 extends in a direction toward the first sidewall 412a.

Before the energy transfer loop 12 is installed in the cover 362, the first sidewall 412a is disposed in an open position (shown in FIGS. 23 and 24). In the open position, the interior volume 410 of the cover 362 is accessible through a side opening 430 of the cover 362. The side opening 430 extends from the first axial end 406 to the second axial end 408 and allows the first and second geothermal exchange pipe sections 56, 58 and the U-shaped portion 360 of energy transfer loop 12 to be laterally inserted into the cover 362.

The leg 426 of the energy transfer loop support member 354 is positioned between the first and second geothermal exchange pipe sections 56, 58. The distal extension 375 of the end rod 352 is inserted into the bore 425 of the cylindrical sleeve 374 of the energy transfer loop support member 354 until the proximal end 378 of the cylindrical sleeve 374 abuts against the shoulder 380 of the end rod 352.

With the first and second geothermal exchange pipe sections 56, 58 and the U-shaped portion 360 of the energy transfer loop 12 disposed in the cover 362, the first sidewall 412a can be moved to the closed position (shown in FIG. 25). In the depicted embodiment, the first sidewall 412a is folded at a fold line 432 to the closed position. In the depicted embodiment, the fold line 432 is disposed at the interface between the first sidewall 412a and the second axial end 408.

The leg 426 is aligned with the first slot 416 in the cover 362. As the first sidewall 412a is folded about the fold line 432, the leg 426 enters the first slot 416. The first sidewall 412a and the leg 426 capture the U-shaped portion 360 of the energy transfer loop 12 in the interior volume 410 of the cover 362. With the first sidewall 412a in the closed position, the first sidewall 412a can be secured to the sidewalls 412 of the cover 362. In one embodiment, the first sidewall 412a is welded to the sidewalls 412 of the cover 362. In the depicted embodiment, an end of the distal extension 375 extends outwardly from the second axial end 408 of the cover 362. In the depicted embodiment, the end of the distal extension 375 extends outwardly from the cover 362 through the opening 424. With the end extending outwardly from the cover 362, drilling fluid can be pumped through the end rod 352 as it is being pushed down the hole.

In depicted embodiments, the geothermal energy transfer loop 12 is directed down the bore with the assistance of a drill string. In other embodiments, it will be appreciated that other types of structures, whether rotatable or non-rotatable can be used to assist in carrying the energy transfer loop into the bore. Such energy transfer loop carrier structures can be formed by a plurality of structures strung together or structures having continuous, uninterrupted lengths.

Claims

CLAIMS:

1. A system for installing an energy transfer loop in a bore, the energy transfer loop including first and second geothermal exchange pipe sections interconnected by a U-shaped portion that couples the first geothermal exchange pipe section in fluid communication with the second geothermal exchange pipe section, the system comprising:

a drilling machine including a thrust drive for pushing a drill string into the ground and for retracting the drill string from the ground, the drilling machine also including a rotational drive for rotating the drill string about a central longitudinal axis of the drill string;

a source of drilling fluid for pumping drilling fluid down the drill string; an end rod that connects to a distal end of the drill string, the end rod including a proximal portion, a distal portion and an intermediate portion positioned between the proximal and distal portions, the proximal portion having a first outer diameter and the distal portion having a second outer diameter that is smaller than the first outer diameter, the intermediate portion having an outer diameter that transitions from the first outer diameter to the second outer diameter, the proximal portion and the intermediate portion defining a fluid passage for receiving the drilling fluid from the drill string, the intermediate portion defining an outlet port for discharging the drilling fluid into the bore during installation of the energy transfer loop;

an energy transfer loop support member that is rotationally connected to the distal portion of the end rod such that the end rod can be rotated relative to the energy transfer loop support member by the drill string, the energy transfer loop support member including a leg that projects laterally outwardly from the distal portion of the end rod, the leg having a first side that faces in a first direction and a second side that faces in a second direction opposite from the first direction, the energy transfer loop support member also including a flange positioned at an outer end of the leg, the flange including a first extension that extends outwardly in the first direction from the leg and cooperates with the first side of the leg to define a first open-sided pocket, the flange also including a second extension that extends outwardly in the second direction from the leg and cooperates with the second side of the leg to define a second open-sided pocket, wherein during installation of the energy transfer loop the leg of the energy transfer loop support member is positioned between the first and second geothermal exchange pipe sections adjacent to the U- shaped portion of the energy transfer loop with a distal portion of the first geothermal exchange pipe section positioned within the first open-sided pocket and a distal portion of the second geothermal exchange pipe section positioned within the second open-sided pocket; and

a cover having a rounded distal nose and an open proximal end, the U- shaped portion of the energy transfer loop and the energy transfer loop support member being insertable into the cover through the open proximal end of the cover, wherein during installation of the energy transfer loop the cover covers the U-shaped portion of the energy transfer loop as well the distal portions of the first and second geothermal exchange pipe sections that are positioned within the first and second open-sided pockets of the energy transfer loop support member.

2. A system for installing an energy transfer loop in a bore, the energy transfer loop including first and second geothermal exchange pipe sections interconnected by a U-shaped portion that couples the first geothermal exchange pipe section in fluid communication with the second geothermal exchange pipe section, the system comprising:

an energy transfer loop carrier structure for directing the energy transfer loop downwardly into the bore;

an energy transfer loop support member that is connected to the energy transfer loop carrier structure, the energy transfer loop support member including a leg that projects laterally outwardly from the energy transfer loop carrier structure and that fits between the first and second geothermal exchange pipe sections adjacent to the U-shaped portion of the energy transfer loop; and

a cover having a rounded distal nose and an open proximal end, the U- shaped portion of the energy transfer loop and the energy transfer loop support member being insertable into the cover through the open proximal end of the cover, wherein during installation of the energy transfer loop the cover covers the U-shaped portion of the energy transfer loop as well distal portions of the first and second geothermal exchange pipe sections between which the leg of the energy transfer loop support member is positioned.

3. The system of claim 2, wherein the energy transfer loop carrier structure includes a passage for delivering fluid down the bore, and wherein the cover defines an opening through the distal nose that aligns with the energy transfer loop carrier structure.

4. The system of claim 3, wherein a distal end of the energy transfer loop carrier structure defines a fluid discharge port, and wherein the distal end of the energy transfer loop carrier structure projects through the opening in the distal nose of the cover.

5. A support member for supporting an energy transfer loop, the energy transfer loop including first and second geothermal exchange pipe sections interconnected by a U-shaped portion that couples the first geothermal exchange pipe section in fluid communication with the second geothermal exchange pipe section, the support member comprising:

a leg adapted for connection to an energy transfer loop carrier structure for directing the energy transfer loop into a bore, the leg having a first side that faces in a first direction and a second side that faces in a second direction opposite from the first direction, the energy transfer loop support member also including a flange positioned at an outer end of the leg, the flange including a first extension that extends outwardly in the first direction from the leg and cooperates with the first side of the leg to define a first open-sided pocket sized for receiving the first geothermal exchange pipe section, the flange also including a second extension that extends outwardly in the second direction from the leg and cooperates with the second side of the leg to define a second open-sided pocket sized for receiving the second geothermal exchange pipe section, wherein during installation of the energy transfer loop the leg of the energy transfer loop support member is positioned between the first and second geothermal exchange pipe sections adjacent to the U- shaped portion of the energy transfer loop with a distal portion of the first geothermal exchange pipe section positioned within the first open-sided pocket and a distal portion of the second geothermal exchange pipe section positioned within the second open-sided pocket.

6. A method for installing an energy transfer loop in a bore, the energy transfer loop including first and second geothermal exchange pipe sections interconnected by a U-shaped portion that couples the first geothermal exchange pipe section in fluid communication with the second geothermal exchange pipe section, the method comprising:

positioning a leg between the first and second geothermal exchange pipe sections adjacent to the U-shaped portion, the leg projecting outwardly from an energy transfer loop carrier structure;

positioning a cover over:

a) the U-shaped portion of the energy transfer loop; b) a lower-most end of the energy transfer loop carrier structure, and c) at least a portion of the leg;

directing the energy transfer loop downwardly into the bore by moving the energy transfer loop carrier structure downwardly into the hole such that a downward force is transferred from the energy transfer loop carrier structure through the leg to the U-shaped portion of the energy transfer loop thereby causing the U- shaped portion of the energy transfer loop to be pushed downwardly into the bore and the first and second geothermal exchange pipe sections to be pulled downwardly into the bore;

maintaining the cover over the U-shaped portion of the energy transfer loop, the lower-most end of the energy transfer loop carrier structure and the at least a portion of the leg while the energy transfer loop directed downwardly into the bore, wherein the cover causes the U-shaped portion of the energy transfer lop and the lower-most end of the energy transfer loop carrier structure to be guided as a unit through the bore; and

withdrawing the energy transfer loop carrier structure and the leg from the bore after the energy transfer loop has been installed in the bore, wherein the cover remains on the U-shaped portion of the energy transfer loop after the energy transfer loop carrier structure and the leg have been withdrawn from the bore.

7. A cover for using in installing a geothermal energy transfer loop with an energy transfer loop carrier structure, the energy transfer loop including first and second geothermal exchange pipe sections interconnected by a U-shaped portion that couples the first geothermal exchange pipe section in fluid communication with the second geothermal exchange pipe section, the cover comprising:

a cover having an interior volume configured for receiving the U-shaped portion of the energy transfer loop and a distal-most end of the energy transfer loop carrier structure, the cover defining a central longitudinal axis that extends along a length of the cover from a rounded, closed lower end to an open upper end, the cover having a side- wall that surrounds the interior volume and extends between the lower and upper ends of the cover member, the side wall defining a hollow, generally triangular inner shape when viewed in cross-section taken along a plane perpendicular to the central longitudinal axis, the generally triangular inner shape having rounded corners.

8. The cover of claim 7, wherein the rounded corners of the generally triangular inner shape extend along curvatures each having a radius of curvature in the range of .50- 1.0 inches.

9. The cover of claim 8, wherein the generally triangular inner shape has a maximum cross-dimension that is less than 4.5 inches.

10. The cover of claim 7, wherein the cover member is a plastic material and the side-wall has a thickness in the range of .03 to .07 inches.

11. The cover of claim 7, wherein the generally triangular inner shape has first, second and third sides, wherein the first and second sides are generally straight and wherein the third side has a concave curvature.

12. The cover of claim 11 , wherein the rounded corners extend along curvatures each defined by a first radius of curvature, and wherein the concave curvature is defined by a second radius of curvature that is larger than the first radius of curvature.