CA2639648C

CA2639648C - System and method for geothermal conduit loop in-ground installation and soil penetrating head therefor

Info

Publication number: CA2639648C
Application number: CA2639648A
Authority: CA
Inventors: Alain Desmeules
Original assignee: DESANTIS BROOKE ERIN
Current assignee: DESANTIS BROOKE ERIN
Priority date: 2008-09-12
Filing date: 2008-09-12
Publication date: 2019-12-31
Anticipated expiration: 2028-09-12
Also published as: EP2334993A1; CA2639648A1; US20100139886A1; EP2334993A4; WO2010028496A1

Abstract

A geothermal in-ground conduit system and a method of constructing and installing same are described. The system comprises at least one loop of flexible tubing adapted to convect a heat exchange liquid therein. The loop has a lower end section and opposed spaced-apart elongated side sections communicating with one another. The lower end section is retained in a soil penetrating head. The soil penetrating head has a leading soil penetrating and ramming face formation. A force transmitting shaft is engageable with the soil penetrating head for transmitting a pushing force against the soil penetrating head to displace same in the soil while pulling the loop and guiding the loop into the soil as the penetrating face forms passages for permanent burial of at least a major portion of the loop together with the soil penetrating head, or the soil penetrating head can be retracted.

Description

SYSTEM AND METHOD FOR GEOTHERMAL CONDUIT
LOOP IN-GROUND INSTALLATION AND SOIL
PENETRATING HEAD THEREFOR
TECHNICAL FIELD
A geothermal, in-ground, conduit system and a method of constructing and installing same, to capture thermal energy stored in soil, are described.
BACKGROUND ART
With the high cost of electricity and gas, more and more interest is directed to the use of other sources of energy and in recent years particular attention has been given to tapping the geothermal energy stored in the ground.
Such energy is renewable as it comes from the sun, but more important such energy does not produce any harmful gas emission which is released in the atmosphere as is the case with combustible products. The use of such energy also results in a cost-saving to heat and cool a building structure. It has been calculated that by using geothermal energy, as opposed to combustible energy, an average house prevents the emission of 2.5 to 5 tons of carbon dioxide into the atmosphere, each year. Accordingly, there is a need to improve the technology to extract this geothermal energy and to develop new methods to tap this energy for existing building structures as well as new building structures.
Nearly half of the thermal energy which comes from the sun is stored in the earth and water on the planet. At a depth of approximately 2 meters, the temperature of the earth is constant during winter months, as well as summer months, and depending on the geographical location of the building it varies between 5 to 12 C.
This is the energy that a geothermal system taps into. Also, a geothermal system produces heat which is more uniform than an electrical or gas heating system. The most popular geothermal system is a

- 2 -close-circuit vertical system wherein tubes are disposed in bore holes or tubes driven into the soil and in which a conduit loop is disposed. The spacing of the tubes that form the conduit loop are very close to one another and usually spaced about 3 inches apart. The tube is then filled with Bentanitejm cement.
Because the conduits are closely spaced and located within a hole bored in rock or in tubes, the heat exchange with the surrounding soil is poor and consequently it is often necessary to have to bore many holes and install many pipes to extract sufficient amount of heat from the ground.
Accordingly, these systems have been found to be expensive.
Usually, for an average household of about 1200 square feet, there is required approximately 750 linear feet of in-ground tubing interconnected in series and into a thermo pump. The thermo pump circulates a heat exchange liquid in the closed loop circuit disposed in the ground and the liquid is used to extract and convect the heat from the soil to the thermo pump which compresses the liquid to extract heat therefrom. During hot summer months, the thermo pump operates in reverse and the geothermal circuit is used to cool the liquid convected through the closed circuit with the liquid extracting heat from inside the building by the thermo pump. It is pointed out that these tubes can extend from 100 to 400 feet into the ground. Often it is necessary, at those depths, to drill through the bedrock and this adds considerably to the cost of the installation of the system.
A vertical installation is preferred over a horizontal installation due to the fact that in a horizontal installation it is necessary to have a very large terrain and usually the tubing is installed in the ground in the form of continuous overlapped loops. A
big advantage of using a geothermal energy heating/cooling system is that the cost of the installation can be recovered within a period of 5 to 10

- 3 -years and thereafter comes the economy wherein the heating and air-conditioning costs are greatly reduced.
SUMMARY OF INVENTION
It is a feature of the present invention to provide a geothermal in-ground conduit system and method of installation which greatly reduces the disadvantage of the prior art mentioned hereinabove.
Another feature of the present invention is to provide a soil penetrating head for use in a geothermal in-ground conduit system to position a flexible tubing loop in the soil and which greatly facilitates the installation of the loop into the soil.
Another feature of the present invention is to provide a geothermal in-ground conduit system comprised of a loop of flexible tubing and a soil penetrating head secured at a lower end of the loop and wherein the head is driven into the soil by a static or dynamic force transmitting shaft which is retractable or which may be utilized as a foundation support pile or a conduit for convecting a heat exchange liquid therein and wherein the soil penetrating head remains imbedded in the soil with the loop of flexible tubing.
Another feature of the present invention is to provide a geothermal in-ground conduit system comprised of a loop of tubing material which is connectable to a soil penetrating head to position the loop of tubing material at a predetermined depth into the soil and wherein the soil penetrating head is retractable after the loop of tubing material has been positioned.
Another feature of the present invention is to provide a geothermal in-ground conduit system which can be installed under the footings of new building structures and to make it accessible to the proprietors of such building structures for future use.

- 4 -Another feature of the present invention is to provide a geothermal in-ground conduit system which can be installed into the ground from inside a foundation of an existing building and which can be placed into the soil surrounding the building at a multitude of desired angles.
Another feature of the present invention is to provide a geothermal in-ground conduit system which does not require drilling through the bedrock.
Another feature of the present invention is to provide a geothermal in-ground conduit system comprised of at least one loop of flexible tubing and wherein the elongated side sections of the loop are spaced-apart a distance sufficient to permit extraction of heat from its surrounding areas without interfering from the surrounding area of the adjacent elongated side sections and wherein there are no tubes required for housing the loop as the side sections are each in direct contact with the surrounding soil thereby greatly increasing the efficiency of such closed loop conduit systems.
According to the above features, from a broad aspect, the present invention provides a geothermal in-ground conduit system comprising at least one loop of flexible tubing material adapted to convect a heat exchange liquid therein. The loop has a lower end section and opposed spaced-apart elongated side sections communicating with the lower end section to form the loop. The lower end section is adapted to be driven in the soil for permanent burial therein with at least a major portion of the side sections and in direct contact with the soil for heat exchange therewith.
According to a further broad aspect, the present invention provides a geothermal in-ground conduit system which comprises at least one loop of flexible tubing adapted to convect a heat exchange liquid therein. The loop has a lower end section and opposed spaced-apart elongated side sections communicating with said lower end section to form

- 5 -the loop. The lower end section of the loop is secured to a soil penetrating head. The soil penetrating head has a leading soil penetrating face formation.
Coupling means is provided with the soil penetrating head to receive a force transmitting shaft to transmit a pushing force against the soil penetrating head to displace the head in the soil while pulling the loop and guiding the loop into the soil as the soil penetrating face formation forms passages in the soil.
According to a further broad aspect of the present invention there is provided a soil penetrating head for use in a geothermal in-ground conduit. The soil penetrating head has a leading soil penetrating face formation.
Coupling means is secured to the soil penetrating head rearwardly of the leading soil penetrating face formation and adapted to receive a force transmitting shaft. The leading soil penetrating and ramming face formation has a convex shaped forward sharp edge and opposed symmetrical shaped side walls tapering outwardly from an apex of the convex forward sharp edge. It also has passage means to receive a lower end section of at least one loop of flexible tubing from a rear end of the soil penetrating head.
According to a still further broad aspect of the present invention the soil penetrating head is detachably secured from the loop of flexible tubing after the loop has been positioned in the soil at a predetermined depth whereby the soil penetrating head is retractable with the loop of flexible tubing remaining buried in the soil.
According to a still further broad aspect of the present invention there is provided a method of constructing an in-ground conduit system to capture thermal energy stored in the ground. The method comprises the steps of securing a lower end section of at least one loop of flexible tubing to a soil penetrating head. The loop has opposed spaced-apart elongated side sections. The soil penetrating head has a leading soil penetrating face formation. The soil penetrating

- 6 -head is engaged by a lower end of a force transmitting shaft supported at a desired angle with respect to a soil surface adjacent a foundation of a building structure. A
pushing force is applied to the force transmitting shaft to displace the soil penetrating head in the soil with the opposed elongated side sections maintained spaced-apart. The soil penetrating head pulls the loop and guides it into the soil as the penetrating face formation forms passages for burial of at least a major portion of the loop.
BRIEF DESCRIPTION OF DRAWINGS
A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which:
FIG. 1 is a fragmented schematic view illustrat-ing the construction of the geothermal in-ground conduit system of the present invention;
FIG. 2 is a perspective view, partly exploded, showing the construction of the soil penetrating head and its connection to a loop of flexible tubing as well as to a force transmitting shaft;
FIG. 3 is a side view showing a modification of the soil penetrating head of Figure 2;
FIG. 4 is a top, rear view showing a further modification of the soil penetrating head;
FIG. 5 is a further rear view showing a still further modification of the soil penetrating head;
FIG. 6 is a schematic illustration of a still further modification of the soil penetrating head;
FIG. 7 is a schematic illustration showing the interconnection of loops of flexible tubing and the use of the force transmitting shaft as a conduit integrated with the loops of flexible tubing and for convecting the heat exchange liquid therein;

- 7 -FIG. 8 is a fragmented side view illustrating the construction of spacing elements connectable with the force transmitting shaft for maintaining the elongated side sections of the flexible tubing loop in spaced-apart relationship as it is drawn into the soil;
FIG. 9 is a simplified perspective view of a pneumatic force applying device utilized to drive the soil penetrating head and the flexible tubing loop into the soil from inside a foundation of an existing building;
FIG. 10 is a perspective view illustrating the construction of a pneumatic force applying device utilized to drive shaft sections of the force transmitting shaft into the soil;
FIG. 11 is a top view of the pneumatic force applying device;
FIG. 12 is a further perspective view of the pneumatic force applying device illustrating an assembly of protection plates secured about the clamping jaws of the device;
FIG. 13 is a fragmented sectional view showing the in-ground conduit system installed under a footing of a foundation structure;
FIG. 14 is a simplified section view illustrating various orientations of the flexible tubing loops that can be installed from inside an existing foundation structure.
FIG. 15 is a schematic illustration of a heavy equipment used to apply a dynamic force against the force transmitting shaft to drive the soil penetrating head and loop of flexible tubing into the soil;
FIG. 16A is a perspective view of a further example of the construction of a soil penetrating head which is adapted to be retracted after the loop of flexible tubing has been positioned into the soil for burial thereinto;
FIG. 168 is a side view of Figure 16A;

- 8 -FIG. 16C is a fragmented side view of the soil penetrating head showing the curved section of the loop of flexible tubing material engaged therewith;
FIGs. 17A to 17C are side views of the soil penetrating head of Figure 16A illustrating how the lower end section of the loop of tubing is positioned into the soil and the soil penetrating head retracted therefrom;
FIG. 17D is a side view similar to Figure 17A but showing a modification of the soil penetrating head wherein a soil penetrating nose member is detachably connected to the leading edge of the soil penetrating head;
FIG. 17E is a side view showing a soil penetrating nose member secured to the lower end section of the loop and engageable by the leading edge of the soil penetrating head;
FIG. 18 is a simplified perspective view showing the construction of the loop of flexible tubing material;
FIGs. 19A and 19B are perspective views showing a further embodiment of a soil penetrating head with a detachable force transmitting shaft engageable therewith;
FIG. 20 is a perspective view showing the construction of the force transmitting shaft lower end;
FIG. 21 is a simplified side view showing how the loop of flexible tubing, as shown in Figure 18, is positioned within the soil; and FIG. 22A is a top view of a hole made in a concrete floor slab of a building structure illustrating a plurality of loops driven in the soil below the slab in different directions;
FIG. 22B is a schematic side view illustrating the position of loops driven into the ground at different angles and with the property boundaries of a building lot; and FIGs. 22C and 22D are similar illustrations of different loop patterns of tubing loops driven in the soil of a building lot.

- 9 -DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings, and more particularly to Figure 1, there is shown a schematic illustration of a building structure 10, herein a residential home, equipped with the geothermal in-ground conduit system 11 of the present invention.
Essentially the system comprises of at least one, herein a plurality of flexible tubing loops 12, each loop being connected in series to form a closed loop conduit circuit which is connected to a thermo pump 13 adapted to circulate a heat exchange liquid within the circuit to extract heat from the soil 14 surrounding the loops for heating the building 10. The pump 13 is conveniently installed inside the building structure 10 or an attached structure 10'. By reversing the operation of the pump 13, heat from inside the building can be cooled by heat exchanging the heat with the heat exchange liquid and circulating into the earth where the soil surrounding the loop cools the heat exchange liquid within the tube thereby extracting heat therefrom. The operation of the thermo pump is well known in the art.
Each of the loops 12 has a pair of elongated, spaced-apart, side sections 15 and 15' and a lower end section 16, hereinshown in phantom line, which is secured to a soil penetrating head 17. The loop is formed of HDPE (high density polyethylene). The loops 12, as well as the soil penetrating head 17, are embedded within the ground at a convenient location, herein close to the foundation wall 17 of the building 10, but they could of course be located further away. The soil penetrating heads 17 of the loops are driven into the ground by a force transmitting shaft, as will be described later, to a predetermined depth or until the soil penetrating head is arrested by the bedrock 18 or otherwise.
Accordingly, the depth of the bedrock could determine how many loops are to be placed into the ground to provide heat for the square footage area of the building , .

- 10 -structure 10 to be heated.
Usually, for a residential building structure of about 2,000 square feet, there is a requirement to dispose approximately 750 feet of tubing into the ground.
However, because, as shown in Figure 1, the flexible tubing is in direct contact with the surrounding soil, it is more efficient in absorbing heat or releasing heat into the ground as opposed to conventional systems and less tubing may be required as compared with the prior art methods where the elongated side sections 15 of the loops are closely spaced and often disposed in a bore hole in a rock surface or in a metal tube driven into the ground.
With reference now to Figure 2, there will be described the construction of the soil penetrating head 17.
As hereinshown the head 17 has a leading soil penetrating and ramming face formation 18 which has a convex-shaped forward sharp edge 19 and opposed symmetrically shaped bowed side walls 20 and 20' extending outwardly from an apex of the convex forward shape edge 19. Coupling means, as hereinshown in the form of a hollow tube section 21, is secured between the symmetrically shaped side walls 20 and 20' and is positioned along a straight central axis 22 which passes through the apex of the sharp edge 19 and at mid-length of the opposed symmetrical shaped side walls and mid-length of the opposed end edges 23 and 23' of the soil penetrating heads 17. The hollow tube section 21 is dimensioned whereby to receive therein a lower end section 24 of a force transmitting shaft 25.
The soil penetrating head 17 is further provided with a curved passage therein to permit the passage of the flexible tubing to form a curved lower end section 16, as hereinshown. Alternatively, as shown in Figure 3, a curved conduit 27 of high density polyethylene may be secured inside the soil penetrating head 17 and be provided with extension portions 27' for connection with a respective one of the elongated side sections 15 and 15' of the loop by socket

- 11 -fusion, butt fusion or electrofusion.
Further, as shown in Figure 3, the tubular connector 21', as hereinshown, is in the form of a pipe section having an engageable formation, herein an inner thread 28 for detachable connection with the threaded end 29 of the force transmitting shaft 25'.
For the installation of the loops 12 into the ground surface 14', a trench 30 may be dug out from the top surface 14' of the ground and in which each loop 12 is driven into the ground by connecting or placing the free end of a force transmitting shaft 25 into the coupling tube 21 for transmitting a directional pushing force against the soil penetrating head to displace the soil penetrating head 17 into the soil 14. As the head is driven into the soil, the leading soil penetrating and ramming face formation 18 displaces the soil and obstacles in its path whereby to form a passage for the loop side sections 15 and 15' as it is pulled into the soil for permanent burial once the soil penetrating head reaches a predetermined depth or is arrested against the bedrock or other hard sub-strata. It is pointed out that the elongated side sections 15 and 15' of the loop are spaced-apart about 18 inches from one another and adjacent loops are positioned about three feet apart. After each of the loops 12 are installed below the ground surface, the loops are interconnected to one another by connectors, such as the connectors 31 shown in Figure 7 and intermediate pipe sections 32, as shown in Figure 1.
Because the tubes are formed from high density plastics, it is preferable to secure the connectors and intermediate tube sections 32 by heat fusing them together or using a melting adhesive whereby there are no leaks in the joints. Once the joints are all interconnected and the free end sections 33 are brought above ground level 14, the trench 30 may be refilled with soil.
As shown in Figure 2, the soil penetrating head 17 is preferably formed of steel or any other suitable hard material such as structural PVC material. The bowed side

- 12 -walls 20 and 20' are also reinforced by transverse rib formations or braces 35. If the soil penetrating head is constructed of a plastic material then a hard metal blade 19' is rigidly secured in the head 17 during the molding of the head 17.
As shown in Figure 4, the soil penetrating head 17 may also be provided with transverse guide flanges 36 to add stability to the head as it penetrates into the soil.
Figure 5 shows a further modification of the soil penetrating head, herein head 17'. As shown, the head 17 is in the form of a cross defined by transverse soil penetrating and ramming face formations 18 and 18' whereby to house a pair of hollow tube sections 27 and 37 which are superimposed under the coupling tube 21 whereby two of the loops can be installed into the ground surface with a single soil penetrating head 17'.
Figure 6 is a schematic illustration showing a further design of the soil penetrating head wherein the head is provided with three elongated flexible tubing sections 40 which are in communication with a hollow coupling tube 21"
through conduits 41.
With such an arrangement, the force transmitting shaft 25" is a hollow shaft permanently secured to the head for convecting the heat exchange liquid therein and into the opposed side sections 40 of the loop. The inner transverse surface area of the force transmitting shaft 25"
is equal to the totality of the inner transverse surface area of the three opposed side sections 40 of the loop.
Figure 7 illustrates an arrangement which is similar, wherein the force transmitting shaft is a hollow shaft with the two elongated side sections 15 and 15' interconnected thereto by conduit connection 15", also illustrated in phantom lines in Figure 2. The heat exchange liquid is convected into the hollow shaft 25" and out through the elongated side sections 15 and 15' whereby to feed the adjacent force transmitting hollow shaft 25"' with the

- 13 -circulation liquid flow repeating with the next section and so on until the liquid convection circuit is complete.
Referring now to Figure 8, there is shown generally at 10 a spacer element 42 which is securable to the force transmitting shaft 25. The force transmitting shaft 25 is a composite shaft consisting of shaft sections 43 interconnected end-to-end by a threaded end section at the end of one shaft section and a threaded bore 45 at the other end of each section 43. In order to maintain the elongated side sections 15 and 15' of the flexible tubing loop in a spaced-apart arrangement as it descends into the soil, the spacer element 42 is connected at selected ones of the connecting joints between the shaft sections 43. As hereinshown the spacer element 42 has projecting arms 46 which are flat with sharp edges and oriented to cut through the soil. The arms 46 are axially aligned with one another and extend transversely of the force transmitting shaft 25 for supporting a guide tube 47 at opposed free ends thereof.
Each of the guide tubes 47 are disposed to receive a respective one of the spaced-apart side sections 15 and 15' of the flexible tube therethrough to maintain the side sections spaced-apart as they are drawn into the soil. The spacer element 42 has a connecting hub 48 also formed with a threaded spigot 49 and a threaded bore 50 whereby to be coupled to the threaded end section 44 and threaded bore 45 of the opposed shaft sections 43.
With reference again to Figure 1, there is shown another use of the force transmitting shaft 25 after the loops have been installed into the soil and the soil penetrating head 17 has reached the bedrock or a solid soil strata. As hereinshown, these force transmitting shafts 25 can be used as a pile which is connected to a bracket 55 immovably secured to the foundation wall 17 to support the foundation should this be desired due to the quality of the

- 14 -soil, i.e., clay or other unstable soils on which the foundation rests.
With reference now to Figures 13 and 1, there is shown another version of the installation of the in-ground conduit circuit or system 11. As shown in these Figures, a series of loops 12', see the right-hand side of Figure 1, are disposed into the ground surface after the excavation hole has been made to build the foundation 55.
After the excavated hole has been surveyed for the footing implantation, the loops of flexible tubing 11 are installed into the ground along a straight line calculated to lie under the foundation footing 56 and offset from the center line 57 of the footing on an interior side 17' of the footing side wall 17. These loops 12 may be interconnected under the top surface 58 of the excavated hole 59 with the free ends of the loop circuit, or of the serially connected loops, extending above the top surface 58. One of these free end sections are herein designated by reference numeral 60. These tube open end sections 60 are disposed in an insulated protective sleeve 61 about which concrete 62 is to be poured and set to form the footing 56.
Accordingly, the entire circuit of a geothermal in-ground conduit system is available to the building to be erected on the foundation from the two free end sections 60 of the circuit ready to be connected by piping to a thermo pump.
Preferably, these two free end sections 60 are located at a location where the mechanical room is to be build With reference now to Figures 9 to 12, there will be described how the geothermal in-ground conduit system of the present invention is installed under an existing building structure.
Figure 9 illustrates an existing building structure foundation, herein constituted by the foundation wall 17, the footing 56 and the concrete floor slab 65. It also shows the joist 66 of an upper floor and these joists 66 form a ceiling 67 which is usually 8 to 9 feet above the

- 15 -concrete floor slab 65. Accordingly, there is very limited space in which to install equipment capable of installing drive piles to install the flexible tubing loops and their associated soil penetrating heads into the ground surface under the foundation. This is accomplished in this restricted space by a pneumatic force applying device 70 which is secured to a foundation anchor plate 71 which is temporarily secured by anchor bolt 72 onto the inner surface 17' of the foundation wall 17 or on the outer surface 65' of the concrete floor slab 65. The anchor plate 71 is provided with a pair of parallel connecting flanges 73, each having a hole 74 for connection to the pneumatic force applying device 70.
As shown in Figures 10, 11 and 12, the pneumatic force applying device has a pair of pistons 75 each having a piston cylinder 76 and a piston rod 77. The piston rods have a piston rod end 78 in the form of a fork adapted to be engaged with a respective one of the holes 74 of the plate 73 by a lock pin 79. The piston cylinders 76 are coupled together in spaced parallel relationship by a force transmission shaft engaging assembly 80. The piston cylinders are connected to a pressurized fluid supply, not shown.
The shaft engaging assembly 80 is comprised of an attachment frame 81 immovably secured to the cylinders 76 to maintain them in spaced-apart parallel relationship. A pair of clamping jaws 82 is slidingly displaceable on a respective angulated side plate 81. The slide plates 81 are retained stationary in spaced-apart facial relationship to support the clamping jaws 82 in a spaced-apart relationship to define a shaft passage 83 therebetween and extending parallel to the cylinders. The clamping jaws 82, when at a lower end of the slide plates, as hereinshown, are spaced further away from one another to define a non-engaging position with the shaft section 43 of the composite force transmitting shaft as

- 16 -previously described. The clamping jaws 82, when moving to an upper end of the slide plates by downward displacement of the cylinders 76 by the application of fluid pressure, converge towards one another and clamp the shaft section 43 in the shaft passage 83 to impart a downward pushing force on the shaft section to drive the soil penetrating head and the flexible tubing loop into the ground surface. Of course, as shown in Figure 9, a hole 90 of sufficient size is first made into the concrete floor slab at an appropriate location where the flexible tubing assembly is to be installed.
With further reference to Figures 10 to 12, the attachment frame 81 is further comprised of a first bridge plate 84 which extends between the cylinders. An aperture 85 is provided in the first bridge plate intermediate the cylinder 76 and dimensioned for receiving the shaft section 43 in close sliding fit therein. A further bridge plate 86 is secured at the top end of the cylinders 76 and extends between the cylinders above the first bridge plate and is provided with a guide edge formation 87 aligned with the aperture 85 whereby to position the shaft intermediate the cylinders and in substantially parallel relationship therewith. Accordingly, by reciprocating the pistons 75, the cylinders move up and down causing the clamping jaws to engage and disengage the pipe sections thereby driving the pipe sections 43 within the soil under the foundation.
Because the pipe sections are short pipe sections, approximately 5 feet in length, it is easy to manipulate them in the space above the concrete floor slab 65 of the foundation and by adding shaft sections and spacer elements 42, the solid penetrating head can be driven deep underground, as previously described.
In order to provide protection to the people operating the pneumatic force applying device the clamping jaws are protected by side protecting plates 89 and a top plate 88 interconnected together by fasteners extending

- 17 -through loops 91 of these plates. It also keeps foreign matter out of the clamping surfaces of the clamping jaws.
Because the piston rod ends 78 are in the form of a fork connected to the connecting flanges 73 of the anchor plates 71, the pneumatic force applying device can be hinged onto the anchor plate whereby the soil penetrating head and associated loops can be positioned into the soil at any angle, such as the angle indicated by axis 93 in Figure 14.
Of course, the anchor plate 71 can also be secured to the top surface 65' of the concrete floor slab 65, as also shown in Figure 14, whereby the soil penetrating head and flexible tubing loop can be driven into the ground along a horizontal axis 94, as shown in Figure 14. Additionally, the pneumatic force applying device 70 could be secured at any location over the concrete floor slab top surface 65' by providing two anchor plates each having a single connecting flange and positioned to each side of a hole 95 formed in the concrete floor slab 65. This would be desirable for example, if the basement area has a dedicated mechanical room in which the thermo pump is to be installed. In such an installation the soil penetrating head 17 and its flexible tubing loop would be driven vertically down through the hole 95, as also illustrated in Figure 14.
Therefore, it is possible to install the in-ground conduit system of the present invention from inside an existing foundation with the loops being directed at any desirable angle into the surrounding soil.
With reference now to Figure 15 there is shown how the geothermal in-ground loop 12 of flexible tubing material can be inserted into the soil 14 from above ground by a heavy equipment 100 having a boom 101 to which is connected an impact device 102 capable of applying a dynamic force against the free end 103 of the force transmitting shaft 25, such equipment is well known in the art. As shown in Figures 18 and 21, the loop of flexible tubing is formed by two sections 104 and 104' of such plastic tubing cut a predetermined

- 18 -length and interconnected at a free end 105 and 105' thereof to a curved lower end section 106 of rigid plastic tubing or metal tubing and sealingly engaged therewith.
This curved lower end section 106 is engaged by the soil penetrating head as illustrated in Figures 16A to 17D, namely soil penetrating head 107 and driven into the soil by the force transmitting shaft 25 as previously described. The soil penetrating head 107 is designed to be retracted from the soil 14 after the head has driven the loop to a predetermined depth or has reached the bedrock surface 18.
With reference now to Figures 16A to 17D there will be described the construction and operation of the soil penetrating head 107. Referring to Figures 16A to 160, there is shown the basic construction of the soil penetrating head 107. It comprises a pair of spaced apart interconnected side walls 108 which are preferably, but not exclusively, constructed of steel and which are interconnected together in spaced parallel relationship by an internal recessed tube abutment member 109. A channel 110 is defined between the side walls 108 in an outer peripheral portion of the soil penetrating head 107. The channel extends along opposed side edges 107' and the leading edge 107" thereof to receive the lower end section 16 and immediate lower portions of the side sections 15 and 15' therein. As shown in Figure 160, the tube abutment member 109 has an outer seating wall 111 which is configured to receive the lower end section 16 of the loop in facial contact therewith. The rear end portion of the soil penetrating head 107 is also provided with a transverse slot 112 to receive the free lower end 113 of the force transmitting shaft 25 in seated engagement therein, as better illustrated in Figure 16A. As shown in Figure 16A, the free end portion 114 of the force transmitting shaft 25 is retained captive between opposed transverse slots 112 of the opposed side walls 108.

- 19 -The free end portion 114 of the force transmitting shaft can be welded to the opposed side walls 108 to retract the soil penetrating head 107 after it has been driven to its intended depth o leave the loop of flexible tubing material buried in the soil, as shown in Figure 220. It can also be freely seated within the opposed slots 112 whereby the force transmitting shaft 25 can be retracted after the soil penetrating head 107 reaches its predetermined depth to be buried together with the lower curved end section of the loop. Figure 22A illustrates the loop buried in the soil together with the soil penetrating head 107. Figures 17A to 170 show how the lower section of the loop is buried into the soil by the displacement of the soil penetrating head, Figure 170 showing the head 107 being retracted by the force transmitting shaft 25. As herein shown, the lower section 16 of the loop is a U-shaped curved section which fits snuggly against the outer seating wall 111 which is convexly curved.
Referring now to Figure 17D, there is shown a soil penetrating nose member 120 which is detachably connected to the leading edge 107" of the opposed side walls 108 of the soil penetrating head 107 to provide ease of penetration of the soil penetrating head into the soil while protecting the curved lower end section 16 of the loop. The soil penetrating nose member is provided with a sharp leading edge 121 and a transverse locating pin 122 secured centrally behind the apex 123 of the head. A
pair of articulated anchor wings 124 is pivotally connected by pivot connection 125 to the forward end portion 126 to hinge rearwardly as the soil penetrating head is driven into the soil.
This soil penetrating nose member 120 remains in the soil under the lower curved section 16 of the loop after the soil penetrating head 107 is retracted. The soil penetrating nose member is retained captive in a slot 127 provided at the apex of the curved lower edge 107" of each of the opposed side walls 108.

, '

- 20 -Figure 17E shows a further embodiment wherein the soil penetrating nose member 120' is provided with an attachment 130 to secure same directly onto the lower curved end section 16 of the loop of flexible tubing. Again, this lower section 16 could be fabricated from a metal pipe or hard industrial plastics material. The soil penetrating nose member 120' is retained in location by the abutment member 109.
It is also made wider than the channel 110 to abut against the outer lower edge 107" of the side walls 108. Any pulling force in the direction of arrow 131 would cause the wings 124 to deploy outwardly, as illustrated in Figure 17E.
With reference now to Figures 19A, 19B and 20 there is shown a further soil penetrating head, herein soil penetrating head 135, and as herein shown, it is formed by a metal member 136 of V-shaped cross section 137 fabricated as a V-shaped soil penetrating head 135 defining a pointed leading end 138 and opposed tapered side walls 139 to provide ease of penetration in the soil. The lower end section 16 of the loop is formed by PVC tube sections 140 interconnected by connectors 141, as is well known in the art.
The side sections 15 and 15' of the loop are formed from flexible plastic tubing such as PVC.
As herein shown, the force transmitting shaft 25 is provided with a coupling 142, as better illustrated in Figure 20, which consists of opposed side walls 143, each provided with a slotted edge 144, configured to receive therein a rear edge portion 144 of the opposed side walls 139 of each side of the soil penetrating head 135 for removable engagement therewith.
The coupling 142 remains in position by the provision of a channel 145 defined between the side walls 143 and which received therebetween the lower end section 16 of the loop. After the soil penetrating head 135 has been driven to a predetermined depth in the soil, the force transmitting shaft and the coupling 142 are retracted. Accordingly, it can be seen that the soil penetrating head may have a variety of designs while

- 21 -performing the function of positioning the loop of flexible tubing material into the soil with the head remaining in the soil or being retracted therefrom.
The method of constructing and installing the in-ground conduit system of the present invention whereby to capture thermal energy stored in the ground, will be briefly summarized. The method consists in securing a curved lower end section of at least one loop of flexible tubing 12 to the soil penetrating head 17. As previously described, each loop has opposed spaced-apart elongated side sections 15 and 15' and a curved end section 16. The side sections 16 are in the form of large coils of tubes located above ground and as the head is driven into the ground these coils unwind. A force transmitting shaft is secured to coupling means of the soil penetrating head and the force transmitting shaft is supported at a desired angle with respect to a soil surface adjacent a foundation of a building or spaced from the foundation of the building or inside the foundation of the building. The force transmitting shaft applies a pushing force to displace the soil penetrating head 17 in the soil with the opposed elongated side sections of the flexible tubing being maintained spaced-apart and being drawn into the soil by the soil penetrating head pulling the loop and guiding it into the soil as the head forms passages for burial of at least a major portion of the loop together with the soil penetrating head after the head is arrested.
Depending on the material of the flexible tubing and its rigidity, the curved lower end section 16 of the loops 12 may be formed several ways as previously described. Further, in the method of installation, spacer elements 42 may be secured to the force transmitting shaft 25 between sections thereof.
The force transmitting shaft 25 may have several forms and can also act as a conduit for the passage of the heat exchange liquid therethrough and in communication with the loop of flexible tubing.

- 22 -As above described, the soil penetrating head may have different configurations and be provided with guide flanges to prevent deviation as it penetrates into the soil.
It may be formed of various materials such as steel, industrial plastics or composite materials that are rigid enough to displace small rocks as it is pushed within the ground. The force transmitting shaft 25 can be coupled to various impacting devices such as high frequency impactors acting on the top end of the force transmitting shaft sections or by a pneumatic force applying device as previously described. Such a device can exert from 5,000 to 75,000 pounds of pressure onto the force transmitting shaft sections. The soil conditions for the installation of the conduit system of the present invention must be such as to permit the displacement of the soil penetrating head therein.
Referring to Figure 22A, there is shown a top view of a hole made in a concrete floor slab, such as the slab 65 shown in Figures 13 and 14 and wherein several tubing loops 12 are driven into the soil under the building and at different radiating angles as well as vertically downwards whereby the flexible tubing loops can extend in the soil under the foundation and within the property lines of the building lot. Figure 22B is a side view showing some of the tubing loops installed in a foundation excavation or through a floor slab of an existing building at different angles and within the lot boundary lines 150. The length of the tubes can be calculated not to extend beyond the subterranean property lines 150 by calculating the angle of the loop and the distance to the property line.
Figure 22C is a further illustration showing an installation of the in-ground conduit system of the present invention and wherein the property lot is a small lot. As hereinshown all of the tubing loops 12 are disposed at different angles and radiate from a common area and at different angles. As previously described with reference to

- 23 -Figure 14, these flexible tubing loops can be driven horizontally and at different angles and can result in an installation such as shown in Figure 22D wherein the property lot is very large and therefore fewer loops may be used to extract heat from the soil.
It is within the ambit of the present invention to cover any obvious modifications of the preferred embodiment described herein provide such modifications fall within the scope of the appended claims.

Claims

- 24 -

1. A geothermal in-ground conduit system comprising:
at least one loop of tubing adapted to circulate a heat exchange liquid therein, the loop having a lower end section and opposed spaced apart elongated side sections communicating with the lower end section to form the loop, the loop being adapted to be driven in soil for permanent burial therein with at least a major portion of the loop in direct contact with the soil for heat exchange therewith; and a soil penetrating head removably retaining the lower end section of the loop and configured to simultaneously form a passage in the soil and pull the loop into the formed passage, the soil penetrating head including coupling means to receive a force transmitting shaft for transmitting a pushing force against the soil penetrating head to displace the soil penetrating head through the soil.

2. The system as defined in claim 1, wherein the soil penetrating head includes a pair of spaced apart side walls interconnected by an internal recessed tube abutment member, the tube abutment member being inwardly offset from a leading and edge and opposed side edges of each of the side walls, the lower end section of the loop being removably received against an outer seating wall of the tube abutment member in a channel defined between the side walls in an outer peripheral portion thereof along the opposed side edges and leading edges.

3. The system as defined in claim 2, wherein the lower end section of the loop is U-shaped, the outer seating wall of the tube abutment member having a convexly curved shape.

4. The system as defined in any one of claims 1 to 3, wherein the coupling means is defined at least in part by the side walls and accessible from a rear end of the soil penetrating head.

5. The system as defined in any one of claims 1 to 4, wherein the coupling means includes engageable formations formed with the soil penetrating head for removable engagement by a coupling secured to a free lower end of the force transmitting shaft.

6. The system as defined in any one of claims 1 to 5, wherein at least the side sections of the loop are formed of flexible plastic material.

7. The system as defined in any one of claims 1 to 5, wherein the loop is formed of flexible plastic material.

8. The system as defined in any one of claims 1 to 6, wherein the lower end section of the loop is formed of rigid material.

9. The system as defined in any one of claims 1 to 8, wherein the spaced-apart side sections of the loop have a free top end, a coupling connector sealingly secured to the free top end for connecting two or more of the loops in series to form a closed loop assembly.

10. The system as defined in any one of claims 1 to 9, wherein the soil penetrating head is formed from steel.

11. The system as defined in any one of claims 1 to 9, wherein the soil penetrating head is formed from high density plastics material having a forward cutting blade defining a sharp edge.

12. The system as defined in any one of claims 1 to 11, wherein a soil penetrating nose member including a sharp leading edge is detachably connected to the soil penetrating head for ease of penetration of the soil penetrating head and protection of the lower end section of the loop.

13. The system as defined in any one of claims 1 to 11, wherein a soil penetrating nose member including a sharp leading edge is secured to the lower end section of the loop and in frictional contact with the soil penetrating head for ease of penetration of the soil penetrating head and protection of the lower end section of the loop, the soil penetrating nose member remaining embedded in the soil with the loop.

14. The system as defined in claim 13, wherein the soil penetrating nose member is provided with articulated anchor wings to anchor the lower end section and the loop in the soil after retraction of the soil penetrating head.

15. The system as defined in any one of claims 1 to 14, further including at least one additional loop, the loop and at least one additional loop being interconnected in series with one another to form a closed-loop tubular conduit circuit having a pair of tube open end sections for connection to heat exchange means for circulating the heat exchange liquid in the tubular circuit, the system further including a footing of a building foundation formed over the closed-loop circuit or at least a portion thereof with the pair of tube open end sections accessible from inside foundation walls formed over the footing.

16. The system as defined in claim 15, wherein the pair of tube open end sections extend through a respective insulated protective sleeve about which concrete is poured and set to form the footing.

17. The system as defined in any one of claims 1 to 16, wherein the force transmitting shaft is detachably connected to the soil penetrating head for retraction of the force transmitting shaft after the head has driven the loop to a desired depth in the soil.

18. The system as defined in any one of claims 1 to 16, wherein the force transmitting shaft is connected to a rear section of the soil penetrating head for retraction of the soil penetrating head after the head has driven the loop to a desired depth in the soil.

19. The system as defined in any one of claims 1 to 16, further comprising the force transmitting shaft, wherein the force transmitting shaft is a solid shaft of hard material sufficient to constitute a pile to add support of a building structure foundation after the soil penetrating head has been driven into the soil to contact bedrock or dense soil, and connection means to immovably secure a top end section of the force transmitting shaft to the foundation.

20. The system as defined in any one of claims 1 to 18, further comprising the force transmitting shaft, wherein the force transmitting shaft includes two or more shaft sections removably interconnected end-to-end, the pushing force being applied against a free top end of each shaft section one after another as they are driven into the soil from inside a pre-formed foundation by a pneumatic force applying device secured to a surface of a concrete foundation wall or floor.

21. The system as defined in claim 20, wherein the pneumatic force applying device includes a pair of pneumatic pistons each having a piston cylinder and a piston rod, the cylinders being coupled together in spaced, side-by-side parallel relationship by a force transmission shaft engaging assembly, the piston rods having piston rod ends secured to a foundation anchor plate configured to be immovably secured to the surface of the foundation wall or floor.

22. The system as defined in claim 21, wherein:
the shaft engaging assembly includes an attachment frame immovably secured to the cylinders to maintain the cylinders in the spaced-apart parallel relationship, a pair of clamping jaws slidingly displaceable on a respective angulated slide plate, the slide plates being retained in spaced-apart facial relationship to support the clamping jaws in a spaced-apart facial relationship to define a shaft passage therebetween extending parallel to the cylinders;
the clamping jaws, when at a lower end of the slide plates, being spaced further away from one another to define a non-engaging position with the shaft when positioned in the shaft passage;
the clamping jaws when moving to an upper end of the slide plates by downward displacement of the cylinders converging towards one another and clamping the shaft in the shaft passage to impart the pushing force on the shaft and the soil penetrating head.

23. The system as defined in claim 22, wherein the attachment frame further comprises a first bridge plate extending between the cylinders, the first bridge plate having an aperture for receiving the shaft in close sliding fit therein, a second bridge plate secured between the cylinders and spaced above the first bridge plate, and guide means formed with the second bridge plate and aligned with the aperture whereby to position and guide the shaft intermediate the cylinders and in substantially parallel relationship therewith.

24. The system as defined in claim 22 or 23, wherein the clamping jaws are caused to move to a lower end of the slide plates to the non-engaging position by upward displacement of the cylinders.

25. The system as defined in any one of claims 21 to 24, wherein the foundation anchor plate is temporarily secured to the surface of the foundation wall or floor by anchor bolts, the anchor plate having a pair of connecting elements for securement of the piston rod ends thereto.

26. The system as defined in any one of claims 21 to 25, wherein the anchor plate is secured at a desired angle to direct the soil penetrating head and the loop in a desired angular direction in the soil.

27. A method of constructing an in-ground conduit system to capture thermal energy stored in the ground, the method comprising:
removably securing a lower end section of at least one loop of tubing to a soil penetrating head, the loop having opposed spaced-apart elongated side sections;
engaging the soil penetrating head to a lower end of a force transmitting shaft supported at a desired angle with respect to a soil surface;
applying a pushing force to the force transmitting shaft to penetrate the soil with the soil penetrating head and form a passage in the soil with the soil penetrating face;
pulling the loop and guiding same into the soil with the soil penetrating head as the soil penetrating face forms the passage for burial of at least a major portion of the loop;
and disengaging the soil penetrating head from the lower end section of the loop.

28. The method as defined in claim 27, further comprising retracting the force transmitting shaft and the soil penetrating head and maintaining the loop buried in the soil.

29. The method as defined in claim 27 or 28, further including maintaining the opposed elongated side sections of the loop in a spaced-apart manner.

30. The method as defined in any one of claims 27 to 29, wherein removably securing the lower end section of at least one loop comprises positioning the lower end section of the loop in a channel defined between side walls of the soil penetrating head and against an outer seating wall thereof.

31. The method as defined in any one of claims 27 to 30, wherein engaging the soil penetrating head comprises positioning the lower end of the force transmitting shaft in a hollow tube section secured in the rear end of the soil penetrating head.

32. The method as defined in any one of claims 27 to 31, wherein the pushing force is applied until the soil penetrating head is arrested by a bedrock surface or a dense soil layer.

33. The method as defined in any one of claims 27 to 32, further comprising, after applying the pushing force:
retracting the force transmitting shaft; and cutting the side sections of the loop above a surface of the soil for interconnection with further loops disposed in the soil and to associated heat exchange equipment.

34. The method as defined in claim 33, wherein cutting the side sections of the loop comprises exposing a predetermined length of the side sections above the surface of the soil to form tube open end sections, the method further comprising positioning an insulated protective sleeve about the tube open end sections and about which concrete is poured to form a footing, the open end sections being accessible inside concrete formation walls formed over the footing.

35. The method as defined in claim 34, further comprising sealingly securing tube connectors to the open end sections for coupling two or more loops in series with one another to form a closed loop conduit circuit when connected to the associated heat exchange equipment.

36. The method as defined in any one of claims 27 to 35, wherein there are at least two loops secured in the soil in side-by-side spaced relationship along substantially straight lines in a hole excavated in the soil and into which a concrete foundation is to be formed, the straight lines being positioned along a footing of a foundation to be formed.

37. The method as defined in any one of claims 27 to 36, further comprising, before penetrating the soil with the soil penetrating head:
forming a hole inside a foundation structure of a building through a foundation wall or floor;
securing an anchor plate to the foundation wall or floor at a desired position relative to the hole;
securing a pneumatic force applying device to the anchor plate; and positioning the force transmission shaft in the pneumatic force applying device for engagement therewith and aligned with the hole at a desired angle to displace the soil penetrating head and the loop into the soil adjacent the foundation structure through the hole.

38. The method as defined in claim 37, wherein positioning the force transmission shaft in the pneumatic force applying device comprises and applying the pushing force to the force transmitting shaft include sequentially positioning each of a plurality of sections of the force transmission shaft in the pneumatic force applying device, actuating the pneumatic force applying device to displace the section, securing a further one of the plurality of sections of the force transmission shaft to a rear end of the section and further actuating the pneumatic force applying device.