U.S. patent application number 12/783084 was filed with the patent office on 2010-11-25 for geothermal heat pump system.
This patent application is currently assigned to THERMAPAN INDUSTRIES INC.. Invention is credited to Emil M. Taraba, Jeffrey M. Taraba.
Application Number | 20100294456 12/783084 |
Document ID | / |
Family ID | 42506115 |
Filed Date | 2010-11-25 |
United States Patent
Application |
20100294456 |
Kind Code |
A1 |
Taraba; Jeffrey M. ; et
al. |
November 25, 2010 |
GEOTHERMAL HEAT PUMP SYSTEM
Abstract
A geothermal heat pump system comprises at least one heat
exchange unit and a ground loop in fluid communication with the at
least one heat exchange unit. The ground loop has a feed into which
heat exchange fluid is delivered by the at least one heat exchange
unit and has a discharge via which circulated heat exchange fluid
is returned to the at least one heat exchange unit. The ground loop
comprises at least one fluid circuit formed of tubing arranged to
define a plurality of laterally spaced, vertical coils buried in
earth beneath a foundation slab of a building structure.
Inventors: |
Taraba; Jeffrey M.; (Fort
Erie, CA) ; Taraba; Emil M.; (Fort Erie, CA) |
Correspondence
Address: |
YOUNG BASILE
3001 WEST BIG BEAVER ROAD, SUITE 624
TROY
MI
48084
US
|
Assignee: |
THERMAPAN INDUSTRIES INC.
Fort Erie
CA
|
Family ID: |
42506115 |
Appl. No.: |
12/783084 |
Filed: |
May 19, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61179497 |
May 19, 2009 |
|
|
|
61304988 |
Feb 16, 2010 |
|
|
|
Current U.S.
Class: |
165/45 ; 165/184;
166/384; 62/260 |
Current CPC
Class: |
F24D 2200/11 20130101;
Y02B 30/12 20130101; Y02B 10/40 20130101; Y02E 10/12 20130101; F24D
3/18 20130101; Y02E 70/30 20130101; Y02E 60/14 20130101; Y02E 10/10
20130101; Y02E 60/142 20130101; F24T 10/10 20180501; F28D 20/0052
20130101 |
Class at
Publication: |
165/45 ; 165/184;
62/260; 166/384 |
International
Class: |
F24J 3/08 20060101
F24J003/08; F28F 1/10 20060101 F28F001/10; F25D 31/00 20060101
F25D031/00; E21B 19/00 20060101 E21B019/00 |
Claims
1. A geothermal heat pump system comprising: at least one heat
exchange unit; and a ground loop in fluid communication with said
at least one heat exchange unit, said ground loop having a feed
into which heat exchange fluid is delivered by said at least one
heat exchange unit and having a discharge via which circulated heat
exchange fluid is returned to said at least one heat exchange unit,
said ground loop comprising at least one fluid circuit formed of
tubing arranged to define a plurality of laterally spaced, vertical
coils buried in earth beneath a foundation slab of a building
structure.
2. A heat pump system according to claim 1 wherein said vertical
coils are connected in series.
3. A heat pump system according to claim 2 wherein said vertical
coils are arranged in at least one row.
4. A heat pump system according to claim 3 wherein said vertical
coils are generally evenly spaced.
5. A heat pump system according to claim 1 wherein said ground loop
comprises a plurality of fluid circuits, each fluid circuit
comprising a plurality of laterally spaced, vertical coils
connected in series.
6. A heat pump system according to claim 5 wherein the vertical
coils of each fluid circuit are arranged in at least one row.
7. A heat pump system according to claim 6 wherein the vertical
coils of each fluid circuit are generally evenly spaced.
8. A heat pump system according to claim 1 wherein each of said
vertical coils generally has the same diameter.
9. A heat pump system according to claim 1 wherein each of said
vertical coils generally has the same number of windings.
10. A heat pump system according to claim 1 wherein the ground loop
further comprises helical tubing wound about foundation walls of
said building structure.
11. A heat pump system according to claim 10 wherein said helical
tubing is in series with said vertical coils.
12. A heat pump system according to claim 11 wherein said helical
tubing is intermediate at least one of said feed and said vertical
coils and said vertical coils and discharge.
13. A heat pump system according to claim 1 wherein the heat
exchange unit comprises a heat pump.
14. A heat pump system according to claim 1 wherein the foundation
slab is a slab on grade.
15. A building structure comprising a foundation having foundation
walls about a foundation slab and a heat pump system according to
claim 1 to control the climate therein.
16. A method of installing a ground loop of a geothermal heat pump
system comprising: excavating earth to create a foundation
excavation; excavating a plurality of laterally spaced, generally
vertical boreholes within the foundation excavation; inserting a
coil of tubing into each borehole, the coils being connected in
series; applying backfill over the coils; and laying a foundation
slab over the backfill.
17. The method of claim 16 further comprising winding a portion of
the ground loop about foundation walls.
18. A method according to claim 17 wherein the winding is performed
prior to construction of the foundation walls.
19. A method according to claim 17 wherein the winding is performed
following construction of the foundation walls.
20. A method according to claim 16 wherein the slab is a slab on
grade.
21. A ground loop for a geothermal heat pump system comprising: a
feed into which heat exchange fluid is delivered by at least one
heat exchange unit; a discharge to return circulated heat exchange
fluid to said at least one heat exchange unit; and at least one
fluid circuit formed of tubing arranged to define a plurality of
laterally spaced, vertical coils buried in earth beneath a
foundation slab of a building structure.
22. A ground loop according to claim 21, wherein the foundation
slab is a slab on grade.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/179,497 to Taraba et al. filed on May 19, 2009
and U.S. Provisional Application No. 61/304,988 to Taraba et al.
filed on Feb. 16, 2010, the contents of which are incorporated
herein by reference in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to geothermal
heating and in particular, to a geothermal heat pump system, to a
building structure incorporating the same and to a method of
installing a geothermal heat pump system ground loop.
BACKGROUND OF THE INVENTION
[0003] Geothermal heat pump systems utilize the natural difference
between the temperature of the earth below the ground surface and
the temperature of the air above the ground surface to create a
thermal driving force for the operation of a heat exchange unit,
which in turn is operated to control the internal climate of a
building structure or the like. Geothermal heat pump systems are
generally considered to be an environmentally-friendly alternative
or supplement to conventional heating and cooling systems, such as
furnaces and air conditioners, due to the fact that geothermal heat
pump systems rely partially on a natural energy source.
[0004] Conventional geothermal heat pump systems comprise a heat
exchange unit that is in fluid communication with a loop of tubing
buried in the ground, commonly referred to as a ground loop. A
heat-exchange fluid, such as a water/ethylene glycol mixture, is
circulated through the ground loop, during which heat is exchanged
between the earth proximate the ground loop and the heat exchange
fluid. When the heat exchange fluid returns to the heat exchange
unit after having circulated through the ground loop, the
temperature difference between the heat exchange fluid being fed to
the ground loop and the heat exchange fluid returning from the
ground loop is used by the heat exchange unit to generate either
heated or cooled air. This heated or cooled air is then pumped into
the interior of a building structure to control its internal
climate.
[0005] A variety of ground loop configurations can be used with
geothermal heat pump systems. For "closed-loop" configurations, in
which the ground loop provides a closed circuit for the circulating
heat exchange fluid, two known configurations are commonly
employed, namely horizontal closed-loop and vertical closed-loop
configurations. In the horizontal closed-loop configuration, the
ground loop is typically laid horizontally in a shallow trench dug
into the ground adjacent the building structure to be serviced by
the geothermal heat pump system. In the vertical closed-loop
configuration, the ground loop is typically placed in a 100 foot to
400 foot deep well formed in ground adjacent the building structure
to be serviced by the geothermal heat pump system.
[0006] Various geothermal heat pump systems have been considered.
For example, U.S. Pat. No. 5,533,356 to DeMasters discloses an
in-ground conduit system for a ground source heat pump. The
in-ground conduit system comprises a conduit loop buried in the
earth to one side of a building. At least one wing member is
mounted on the conduit loop to contact the ground and resist upward
movement of the conduit loop.
[0007] U.S. Pat. No. 5,339,890 to Rawlings discloses a ground
source heat pump system comprising a subterranean piping
installation constructed of a plurality of modular heat exchange
units. The subterranean piping installation is buried to one side
of a building structure.
[0008] As will be appreciated, it can be costly to install a
geothermal heat pump system for servicing a building structure once
the building structure has been constructed, owing to the effort
required to excavate the yard surrounding building structure to
install the ground loop. In cases where sufficient land or yard
space is not available to accommodate the ground loop, other
non-conventional provisions need to be made to install the ground
loop, which can require complex and costly excavation adding to the
cost of the geothermal heat pump system. As a result, there exists
a need for a geothermal heat pump system that has a low
installation cost and that is compatible with building structures
associated with limited yard space.
[0009] It is therefore an object of the present invention to
provide a novel geothermal heat pump system, a novel building
structure incorporating the geothermal heat pump system and a novel
method of installing a geothermal heat pump system ground loop.
SUMMARY OF THE INVENTION
[0010] Accordingly, in one aspect there is provided a geothermal
heat pump system comprising at least one heat exchange unit; and a
ground loop in fluid communication with said at least one heat
exchange unit, said ground loop having a feed into which heat
exchange fluid is delivered by said at least one heat exchange unit
and having a discharge via which circulated heat exchange fluid is
returned to said at least one heat exchange unit, said ground loop
comprising at least one fluid circuit formed of tubing arranged to
define a plurality of laterally spaced vertical coils buried in
earth beneath a foundation slab of a building structure.
[0011] In one embodiment, the vertical coils are connected in
series and are arranged in at least one row. The vertical coils may
also be generally evenly spaced.
[0012] In another embodiment, the ground loop comprises a plurality
of fluid circuits with each fluid circuit comprising a plurality of
laterally spaced, vertical coils connected in series. The vertical
coils of each fluid circuit are arranged in at least one row and
are generally evenly spaced.
[0013] In yet another embodiment, the ground loop further comprises
helical tubing wound about the foundation walls of the building
structure.
[0014] According to another aspect, there is provided a method of
installing a ground loop of a geothermal heat pump system
comprising excavating earth to create a foundation excavation;
excavating a plurality of laterally spaced, generally vertical
boreholes within the foundation excavation; inserting a coil of
tubing into each borehole, the coils being connected in series;
applying backfill over the coils; and laying a foundation slab over
the backfill.
[0015] In one embodiment, a portion of the ground loop is wound
about foundation walls. The winding may be performed prior to
construction of the foundation walls or after construction of the
foundation walls.
[0016] According to yet another aspect, there is provided a ground
loop for a geothermal heat pump system comprising a feed into which
heat exchange fluid is delivered by at least one heat exchange
unit; a discharge to return circulated heat exchange fluid to said
at least one heat exchange unit; and at least one fluid circuit
formed of tubing arranged to define a plurality of laterally
spaced, vertical coils buried in earth beneath a foundation slab of
a building structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Embodiments will now be described more fully with reference
to the accompanying drawings in which:
[0018] FIG. 1 is a cross-sectional view of a building structure
serviced by a geothermal heat pump system;
[0019] FIG. 2 is another cross-sectional view of the building
structure of FIG. 1, partially cut away, showing the geothermal
heat pump system in top plan;
[0020] FIG. 3 is a cross-sectional view, similar to FIG. 2, showing
another embodiment of a geothermal heat pump system;
[0021] FIG. 4 is a cross-sectional view, similar to FIG. 2, showing
yet another embodiment of a geothermal heat pump system;
[0022] FIG. 5 is a cross-sectional view of a building structure
serviced by yet another embodiment of a geothermal heat pump
system;
[0023] FIG. 6 is another cross-sectional view of the building
structure of FIG. 5, partially cut away, showing the geothermal
heat pump system in top plan;
[0024] FIG. 7 is a cross-sectional view of a building structure
serviced by yet another embodiment of a geothermal heat pump
system;
[0025] FIG. 8 is another cross-sectional view of the building
structure of FIG. 7, partially cut away, showing the geothermal
heat pump system in top plan;
[0026] FIG. 9 is a cross-sectional view, similar to FIG. 8, showing
yet another embodiment of a geothermal heat pump system;
[0027] FIG. 10 is a cross-sectional view, similar to FIG. 8,
showing yet another embodiment of a geothermal heat pump
system;
[0028] FIG. 11 is a cross-sectional view of a building structure
serviced by yet another embodiment of a geothermal heat pump
system;
[0029] FIG. 12 is another cross-sectional view of the building
structure of FIG. 11, partially cut away, showing the geothermal
heat pump system in top plan;
[0030] FIG. 13 is a cross-sectional view of a building structure
serviced by yet another embodiment of a geothermal heat pump
system;
[0031] FIG. 14 is another cross-sectional view of the building
structure of FIG. 13, partially cut away, showing the geothermal
heat pump system in top plan;
[0032] FIG. 15 is a cross-sectional view of a building structure
serviced by still yet another embodiment of a geothermal heat pump
system; and
[0033] FIG. 16 is another cross-sectional view of the building
structure of FIG. 15, partially cut away, showing the geothermal
heat pump system in top plan.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0034] The following description is directed to a geothermal heat
pump system that comprises a ground loop inserted into the earth
directly beneath the foundation slab of a building structure or the
like. The ground loop is inserted into the earth after the
foundation excavation has been completed, but before the foundation
has been constructed, and more specifically before the foundation
slab has been laid. This construction sequence takes advantage of
the excavation carried out for the foundation, and therefore
obviates the need for significant further excavation for the ground
loop, which reduces the cost of installation of the geothermal heat
pump system. The ground loop comprises a plurality of laterally
spaced, generally vertical coils, the boreholes for which can be
easily excavated and arranged during the installation stage. As the
characteristics of the vertical coils, such as their number,
density of windings, and spacing, are related to the quantity of
heat transferred between the earth and the heat exchange fluid
circulating within the ground loop, the use of coils in this
arrangement provides a simple way to control the quantity of heat
transfer, allowing the design requirements of different individual
geothermal heat pump systems to be met. Various embodiments of
geothermal heat pump systems will now be described with particular
reference to FIGS. 1 to 16.
[0035] Turning now to FIGS. 1 and 2, a geothermal heat pump system
is shown and is generally indicated by reference numeral 20. In
this example, geothermal heat pump system 20 services a building
structure 50 in the form of a house. Those of skill in the art will
appreciate that the building structure 50 need not be residential
and in fact can be virtually any building structure whose internal
climate needs to be controlled. Geothermal heat pump system 20
comprises a heat exchange unit 24 and a ground loop 26 in fluid
communication with the heat exchange unit 24. The heat exchange
unit 24 is located in the basement 52 of the building structure 50
and rests on the foundation slab 54 of the building structure 50.
The ground loop 26 is buried in the earth 28 directly beneath the
foundation slab 54. Heat exchange fluid circulates through the heat
exchange unit 24 and the ground loop 26. The heat exchange fluid
can be any suitable heat exchange medium and in this embodiment is
a water/ethylene glycol mixture.
[0036] In this embodiment, the ground loop 26 is formed of
high-density polyethylene tubing that is arranged to form a single
fluid circuit so that heat exchange fluid fed into the ground loop
26 by the heat exchange unit 24 follows a serial path through the
tubing before returning to the heat exchange unit. To that end, the
ground loop 26 comprises a feed conduit 30 receiving the heat
exchange fluid discharged by the heat exchange unit 24, a discharge
conduit 32 returning the heat exchange fluid that has circulated
through the ground loop 26 back to the heat exchange unit 24 and a
plurality of generally equally spaced, vertical coils 34, in this
embodiment five (5) coils, connected in series and arranged in a
row that is intermediate the feed conduit 30 and the discharge
conduit 32. Each vertical coil 34 in this embodiment has generally
the same diameter and the same number of windings. Making use of
vertical coils 34 enables the total length of the ground loop 26 to
be increased while reducing the amount of excavation required to
install the ground loop 26.
[0037] In operation, the heat exchange unit 24 delivers heat
exchange fluid to the feed conduit 30 of the ground loop 26. Heat
exchange fluid entering the feed conduit 30 flows through the
tubing passing through each of the vertical coils 34 in succession
before being returned to the heat exchange unit 24 via the
discharge conduit 32. During flow of the heat exchange fluid
through the ground loop 26, heat is transferred between the earth
28 surrounding the ground loop 26 and the heat exchange fluid. The
difference in temperature between the heat exchange fluid being fed
into the ground loop 26 by the heat exchange unit 24 and the heat
exchange fluid being returned to the heat exchange unit 24 from the
ground loop 26 creates a thermal driving force that is used by the
heat exchange unit 24. In particular, the heat exchange unit 24
comprises a second internal loop containing a refrigerant (not
shown). The thermal driving force is utilized by the heat exchange
unit 24 to drive the refrigerant through a vapor-compression
refrigeration cycle, which in turn is used to generate heated or
cooled air, as is well known to those of skill in the art. This
heated or cooled air is then pumped by heat exchange unit 24 into
the interior of building structure 50 to control the internal
climate within the building structure 50.
[0038] During installation of the geothermal heat pump system 20,
after the ground for the foundation of the building structure 50
has been excavated, vertical boreholes sized to accommodate the
vertical coils 34 are formed in the earth. As each vertical coil 34
has generally the same diameter, the boreholes can be readily
formed using a single auger or other suitable excavation tool. Once
the boreholes have been formed, each vertical coil 34 is positioned
in a respective borehole. The vertical coils 34 are then backfilled
thereby covering the vertical coils with earth 28. Once the
appropriate amount of backfilling has been achieved, the foundation
slab 54 is laid on the earth 28 and the remainder of the foundation
constructed. The feed and discharge conduits 30 and 32
respectively, of the ground loop 26 are then fed through one of the
foundation walls 56 and backfill is placed around the foundation
walls 56. As will be appreciated, this construction sequence takes
advantage of the excavation that is required for constructing the
foundation of the building structure 50 eliminating the requirement
for separate excavation for the ground loop 26. As the ground loop
26 is positioned directly below the foundation slab 54 of the
building structure 50, the geothermal heat pump system 20 is
compatible for use with building structures associated with limited
or no yard space.
[0039] As will be appreciated, many factors determine the
effectiveness and efficiency of the geothermal heat pump system 20.
For example, the quantity of heat transferred between the earth 28
surrounding the ground loop 26 and the heat exchange fluid
circulating through ground loop 26, the efficiency of the heat
exchange unit 24, and the size and energy efficiency of the
building structure 50 all contribute to the effectiveness and
efficiency of the geothermal heat pump system 20. With regard to
the first factor, the quantity of heat transferred between the
earth 28 surrounding the ground loop 26 and the heat exchange fluid
flowing through the ground loop 26 is itself determined by a number
of different factors, including but not limited to the average
seasonal temperature of the earth 28, the average temperature
difference between the earth 28 and the air above the ground
surface 28a, the soil characteristics and groundwater content of
the earth, and the configuration of the ground loop 26.
Consequently, and as will be appreciated, the configuration of the
ground loop 26, such as the total length of the ground loop 26, the
depth of the vertical coils 34, the density of the vertical coil
windings, the lateral spacing of the vertical coils 34, and the
number of vertical coils 34, impacts the efficiency of the
geothermal heat pump system 20. Depending on the environment, for a
given geothermal heat pump system installation one or more of these
configuration parameters may be varied to suit particular
needs.
[0040] FIG. 3 shows an alternative embodiment of a geothermal heat
pump system 120 servicing the building structure 50. In this
embodiment, similar to the previous embodiment, the ground loop 126
is formed of high-density polyethylene tubing that is arranged to
form a single fluid circuit so that heat exchange fluid fed into
the ground loop 126 by the heat exchange unit 124 follows a serial
path through the tubing before returning to the heat exchange unit.
The ground loop 126 comprises a feed conduit 130 receiving the heat
exchange fluid discharged by the heat exchange unit 124, a
discharge conduit 132 returning the heat exchange fluid that has
circulated through the ground loop 126 back to the heat exchange
unit 124 and a plurality of generally equally spaced, vertical
coils 134 connected in series and arranged in two generally
parallel rows. Each row of vertical coils 134 comprises five (5)
coils. Similar to the previous embodiment, each vertical coil 134
has generally the same diameter and the same number of
windings.
[0041] Yet another embodiment of a geothermal heat pump system 220
servicing the building structure 50 is shown in FIG. 4. In this
embodiment similar to the previous embodiments, the ground loop 226
is formed of high-density polyethylene tubing. Unlike the previous
embodiments however, the tubing is arranged to form a pair of
parallel fluid circuits 229a and 229b with each fluid circuit being
in communication with the heat exchange unit 224. Each fluid
circuit comprises a feed conduit 230 receiving heat exchange fluid
discharged by the heat exchange unit 224, a discharge conduit 232
returning the heat exchange fluid that has circulated through the
tubing of the fluid circuit back to the heat exchange unit 224 and
a plurality of generally equally spaced, vertical coils 234, in
this embodiment five (5) coils, connected in series and arranged in
a row. Each vertical coil 234 in this embodiment has generally the
same diameter and the same number of windings. The two rows of
vertical coils 234 of the fluid circuits 229a and 229b are
generally parallel. The use of two separate parallel fluid circuits
provides the ground loop 226 with an increased total length and
allows each fluid circuit to be operated individually. Thus, when
only a small quantity of heat transfer is required to control the
climate of the building structure 50, for example, such as in mild
weather, only one of the fluid circuits needs to be used to
circulate heat exchange fluid.
[0042] FIGS. 5 and 6 show still yet another embodiment of a
geothermal heat pump system 320 servicing a building structure 350
in the form of a house. Geothermal heat pump system 320 comprises a
heat exchange unit 324 and a ground loop 326 in fluid communication
with the heat exchange unit 324. The heat exchange unit 324 is
located in the basement 352 of the building structure 350 and rests
on the foundation slab 354 of the building structure 350. The
ground loop 326 receives heat exchange fluid discharged by the heat
exchange unit 324 and returns the heat exchange fluid to the heat
exchange unit 324 after the heat exchange fluid has circulated
through the ground loop 326.
[0043] Similar to the previous embodiments, the ground loop 326 is
formed of high-density polyethylene tubing. The ground loop 326 is
arranged to form a single fluid circuit so that heat exchange fluid
fed into the ground loop 326 by the heat exchange unit 324 follows
a serial path through the tubing before returning to the heat
exchange unit 324. In this embodiment, the ground loop 326
comprises a feed conduit 330 receiving the heat exchange fluid
discharged by the heat exchange unit 324, a discharge conduit 332
returning the heat exchange fluid that has circulated through the
ground loop 326 back to the heat exchange unit 324, a helical
winding 340 coupled to the feed conduit 320 that is buried in the
earth 328 below the frost line 342 and is wound about the
foundation walls 356 of the building structure 350, a helical
winding 344 coupled to the discharge conduit 332 that is buried in
the earth 328 below the frost line 342 and is wound about the
foundation walls 356 and a plurality of generally equally spaced,
vertical coils 334 connected in series and arranged in a row that
interconnects the helical windings 340 and 344. Each vertical coil
334 has generally the same diameter and the same number of
windings. The helical windings 340 and 344 enable the length of the
ground loop 326 to be extended, and enable any heat transferred
between earth 328 surrounding the foundation walls 356 and the heat
exchange fluid being circulated through ground loop 226 to
contribute to the total heat transfer. In one scenario, the length
of the ground loop 326 as compared to the previous embodiments
could be kept constant, and as a result use of the helical windings
340 and 344 allows the number of vertical coils 334 to be reduced,
thus reducing the amount of excavation required to install the
vertical coils 334.
[0044] The installation of the ground loop 326 can be carried out
in one or more stages. For single stage installation, ground loop
326 is installed following the foundation excavation but prior to
both the laying of the foundation slab 354 and the construction of
the foundation walls 356. In other words, both the vertical coils
334 and the helical windings 340 and 344 are installed in the earth
328 before the foundation slab 354 is laid and before the
foundation walls 356 are built. Alternatively, for multiple stage
installation, the vertical coils 334 are initially inserted into
boreholes formed in the earth 328 and the construction of the
foundation proceeds so that the foundation slab 354 is laid and the
foundation walls 356 built. Once the foundation walls are built,
the helical windings 340 and 344 are installed.
[0045] If desired, the helical windings 340 and 344 may form an
individual fluid circuit that is in parallel with the vertical
coils 334 rather than being connected in series with the vertical
coils.
[0046] FIGS. 7 and 8 show yet another embodiment of a geothermal
heat pump system, which is generally indicated by reference numeral
420. In this example, geothermal heat pump system 420 services a
building structure 450 in the form of a commercial building. Those
of skill in the art will appreciate that the building structure 450
need not be commercial and in fact can be virtually any building
structure whose internal climate needs to be controlled. Geothermal
heat pump system 420 comprises a heat exchange unit 424 and a
ground loop 426 in fluid communication with the heat exchange unit
424. The heat exchange unit 424 is located in the building
structure 450 and rests on a foundation slab 454, which in this
case is a slab on grade. The foundation walls 456 extend downwardly
beneath the foundation slab 454, and are supported by footings 458.
The ground loop 426 is buried in the earth 428 directly beneath the
foundation slab 454. Heat exchange fluid circulates through the
heat exchange unit 424 and the ground loop 426. The heat exchange
fluid can be any suitable heat exchange medium and in this
embodiment is a water/ethylene glycol mixture.
[0047] Similar to the previous embodiments, the ground loop 426 is
formed of high-density polyethylene tubing that is arranged to form
a single fluid circuit so that heat exchange fluid fed into the
ground loop 426 by the heat exchange unit 424 follows a serial path
through the tubing before returning to the heat exchange unit. To
that end, the ground loop 426 comprises a feed conduit 430
receiving the heat exchange fluid discharged by the heat exchange
unit 424, a discharge conduit 432 returning the heat exchange fluid
that has circulated through the ground loop 426 back to the heat
exchange unit 424 and a plurality of generally equally spaced,
vertical coils 434, in this embodiment five (5) coils, connected in
series and arranged in a row that is intermediate the feed conduit
430 and the discharge conduit 432. Each vertical coil 434 in this
embodiment has generally the same diameter and the same number of
windings.
[0048] During installation of the geothermal heat pump system 420,
after the ground for the foundation of the building structure 450
has been excavated and foundation walls 456 have been constructed,
vertical boreholes sized to accommodate the vertical coils 434 are
formed in the earth. As each vertical coil 434 has generally the
same diameter, the bores can be readily formed using a single auger
or other suitable excavation tool. The boreholes extend below the
bottoms of foundation walls 456 and associated footings. Once the
boreholes have been formed, each vertical coil 434 is positioned in
a respective borehole and the feed and discharge conduits 430 and
432 are positioned to extend above the foundation slab location.
The volume between foundation walls 456 is then backfilled, thereby
covering the vertical coils 434 with earth 428. Once the
appropriate amount of backfilling has been achieved, the foundation
slab 454 is laid on the earth 428 at ground surface level 428a, and
the remainder of the building structure 450 is constructed. The
feed and discharge conduits 430 and 432 respectively, of the ground
loop 426 which extend through the foundation slab 454 are then
connected to the heat exchange unit 424. As will be appreciated,
this construction sequence takes advantage of the excavation that
is required for constructing the foundation of the building
structure 450 eliminating the requirement for separate excavation
for the ground loop 426. As the ground loop 426 is positioned
directly below the foundation slab 454 of the building structure
450, the geothermal heat pump system 420 is compatible for use with
building structures associated with limited or no yard space.
[0049] FIG. 9 shows an alternative embodiment of a geothermal heat
pump system 520 servicing the building structure 450. In this
embodiment, similar to the previous embodiment, the ground loop 526
is formed of high-density polyethylene tubing that is arranged to
form a single fluid circuit so that heat exchange fluid fed into
the ground loop 526 by the heat exchange unit 524 follows a serial
path through the tubing before returning to the heat exchange unit.
The ground loop 526 comprises a feed conduit 530 receiving the heat
exchange fluid discharged by the heat exchange unit 524, a
discharge conduit 532 returning the heat exchange fluid that has
circulated through the ground loop 526 back to the heat exchange
unit 524 and a plurality of generally equally spaced, vertical
coils 534 connected in series and arranged in two generally
parallel rows. Each row of vertical coils 534 comprises five (5)
coils. Similar to the previous embodiment, each vertical coil 534
has generally the same diameter and the same number of
windings.
[0050] Yet another embodiment of a geothermal heat pump system 620
servicing the building structure 450 is shown in FIG. 10. In this
embodiment similar to the previous embodiments, the ground loop 626
is formed of high-density polyethylene tubing. The tubing is
arranged to form a pair of parallel fluid circuits 629a and 629b
with each fluid circuit being in communication with the heat
exchange unit 624. Each fluid circuit comprises a feed conduit 630
receiving heat exchange fluid discharged by the heat exchange unit
624, a discharge conduit 632 returning the heat exchange fluid that
has circulated through the tubing of the fluid circuit back to the
heat exchange unit 624 and a plurality of generally equally spaced,
vertical coils 634, in this embodiment five (5) coils, connected in
series and arranged in a row. Each vertical coil 634 in this
embodiment has generally the same diameter and the same number of
windings. The two rows of vertical coils 634 of the fluid circuits
629a and 629b are generally parallel. The use of two separate
parallel fluid circuits provides the ground loop 626 with an
increased total length and allows each fluid circuit to be operated
individually. Thus, when only a small quantity of heat transfer is
required to control the climate of the building structure 450, for
example, such as in mild weather, only one of the fluid circuits
needs to be used to circulate heat exchange fluid.
[0051] FIGS. 11 and 12 show yet another embodiment of a geothermal
heat pump system 720 servicing a building structure 750. Geothermal
heat pump system 720 comprises a heat exchange unit 724 and a
ground loop 726 in fluid communication with the heat exchange unit
724. The heat exchange unit 724 is located in the building
structure 750 and rests on a foundation slab 754 of the building
structure 750, which is a slab on grade. The ground loop 726
receives heat exchange fluid discharged by the heat exchange unit
724 and returns the heat exchange fluid to the heat exchange unit
724 after the heat exchange fluid has circulated through the ground
loop 726.
[0052] Similar to the previous embodiments, the ground loop 726 is
formed of high-density polyethylene tubing. The ground loop 726 is
arranged to form a single fluid circuit so that heat exchange fluid
fed into the ground loop 726 by the heat exchange unit 724 follows
a serial path through the tubing before returning to the heat
exchange unit 724. In this embodiment, the ground loop 726
comprises a feed conduit 730 receiving the heat exchange fluid
discharged by the heat exchange unit 724, a discharge conduit 732
returning the heat exchange fluid that has circulated through the
ground loop 726 back to the heat exchange unit 724, a helical
winding 740 coupled to the feed conduit 730 that is buried in the
earth 728 below the frost line 742 and is wound about the exterior
of the foundation walls 756 of the building structure 750, and a
plurality of generally equally spaced, vertical coils 734 connected
in series and arranged in a row. Each vertical coil 734 has
generally the same diameter and the same number of windings. The
helical winding 740 enables the length of the ground loop 726 to be
extended, and enables any heat transferred between earth 728
surrounding the foundation walls 756 and the heat exchange fluid
being circulated through ground loop 726 to contribute to the total
heat transfer. In one scenario, the length of the ground loop 726
as compared to the embodiments of FIGS. 7 to 10 could be kept
constant, and as a result use of the helical winding 740 allows the
number of vertical coils 734 to be reduced, thus reducing the
amount of excavation required to install the vertical coils
734.
[0053] The installation of the ground loop 726 can be carried out
in one or more stages. For single stage installation, ground loop
726 is installed following the foundation excavation but prior to
the construction of the foundation walls 756. In other words, both
the vertical coils 734 and the helical winding 740 are installed in
the earth 728 before the foundation walls 756 are built.
Alternatively, for multiple stage installation, the vertical coils
734 are initially inserted into boreholes formed in the earth 728
and the construction of the foundation proceeds so that the
foundation walls are constructed, the volume between foundation
walls is backfilled, and the foundation slab 754 is laid. Once the
foundation has been constructed, the helical winding 740 is
installed. Those of skill in the art will appreciate that still
other alternative installation sequences are possible.
[0054] If desired, the helical winding 740 may form an individual
fluid circuit that is in parallel with the vertical coils 734
rather than being connected in series with the vertical coils.
[0055] In the embodiment of FIGS. 11 and 12, the helical winding is
wound about the exterior of the foundation walls. Alternatively,
the helical winding may be wound within the interior of the
foundation walls. For example, FIGS. 13 and 14 show yet another
embodiment of a geothermal heat pump system 820 servicing a
building structure 850. Geothermal heat pump system 820 comprises a
heat exchange unit 824 and a ground loop 826 in fluid communication
with the heat exchange unit 824. The heat exchange unit 824 is
located in the building structure 850 and rests on the foundation
slab 854, which is a slab on grade. The ground loop 826 receives
heat exchange fluid discharged by the heat exchange unit 824 and
returns the heat exchange fluid to the heat exchange unit 824 after
the heat exchange fluid has circulated through the ground loop
826.
[0056] Similar to the previous embodiments, the ground loop 826 is
formed of high-density polyethylene tubing. The ground loop 826 is
arranged to form a single fluid circuit so that heat exchange fluid
fed into the ground loop 826 by the heat exchange unit 824 follows
a serial path through the tubing before returning to the heat
exchange unit 824. In this embodiment, the ground loop 826
comprises a feed conduit 830 receiving the heat exchange fluid
discharged by the heat exchange unit 824, a discharge conduit 832
returning the heat exchange fluid that has circulated through the
ground loop 826 back to the heat exchange unit 824, a helical
winding 844 coupled to the feed conduit 830 that is buried in the
earth 828 and is wound within the interior of foundation walls 856
of the building structure 850, and a plurality of generally equally
spaced, vertical coils 834 connected in series and arranged in a
row.
[0057] The installation of the ground loop 826 can be carried out
in one or more stages. For single stage installation, ground loop
826 is installed following the foundation excavation and the
construction of the foundation walls 856. In other words, both the
vertical coils 834 and the helical winding 844 are installed in the
earth 828 prior to backfilling and therefore prior to the laying of
the foundation slab 854. Alternatively, for multiple stage
installation, the vertical coils 834 are initially inserted into
boreholes formed in the earth 828 and the foundation walls 856 are
then constructed. Once the foundation walls are built, the helical
winding 844 is installed and the volume between foundation walls
856 is backfilled. Those of skill in the art will appreciate that
still other alternative installation sequences are possible.
[0058] FIGS. 15 and 16 show still yet another embodiment of a
geothermal heat pump system 920 servicing a building structure 950.
Geothermal heat pump system 920 comprises a heat exchange unit 924
and a ground loop 926 in fluid communication with the heat exchange
unit 924. The heat exchange unit 924 is located in the building
structure 950 and rests on the foundation slab 954, which is a slab
on grade. The ground loop 926 receives heat exchange fluid
discharged by the heat exchange unit 924 and returns the heat
exchange fluid to the heat exchange unit 924 after the heat
exchange fluid has circulated through the ground loop 926.
[0059] Similar to the previous embodiments, the ground loop 926 is
formed of high-density polyethylene tubing. The ground loop 926 is
arranged to form a single fluid circuit so that heat exchange fluid
fed into the ground loop 926 by the heat exchange unit 924 follows
a serial path through the tubing before returning to the heat
exchange unit 924. In this embodiment, the ground loop 926
comprises a feed conduit 930 receiving the heat exchange fluid
discharged by the heat exchange unit 924, a discharge conduit 932
returning the heat exchange fluid that has circulated through the
ground loop 926 back to the heat exchange unit 924, a helical
winding 940 coupled to the feed conduit 930 that is buried in the
earth 928 below the frost line 942 and is wound about the exterior
of foundation walls 956 of the building structure 950, a helical
winding 944 coupled to the feed conduit 930 that is buried in the
earth 928 and is wound within the interior of foundation walls 956
of the building structure 950, and a plurality of generally equally
spaced, vertical coils 934 connected in series and arranged in a
row.
[0060] The installation of the ground loop 926 can be carried out
in one or more stages. For single stage installation, ground loop
926 is installed following the foundation excavation and the
construction of the foundation walls 956. In other words, the
vertical coils 934 and the helical windings 940 and 944 are
installed in the earth 928 prior to backfilling and therefore prior
to the laying of the foundation slab 954. Alternatively, for
multiple stage installation, the vertical coils 934 are initially
inserted into boreholes formed in the earth 928 and the helical
winding 940 is installed, and the foundation walls 956 are then
constructed. Once the foundation walls are built, the interior
helical winding 944 is installed. Those of skill in the art will
appreciate that still other alternative installation sequences are
possible.
[0061] The tubing of each fluid circuit may comprise a single,
integral length of tubing or alternatively may comprise two or more
lengths of interconnected tubing segments.
[0062] Although the heat exchange fluid is described above as being
a water/ethylene glycol mixture, the heat exchange fluid may be any
suitable material or substance. Alternatively, the system may be a
direct exchange (DX) heat pump system, in which the ground loop is
configured to have refrigerant circulated therethrough.
[0063] In the embodiments described above, the vertical coils of
each fluid circuit are described and shown as being of generally
the same diameter and having the same number of windings. Those of
skill in the art will appreciate that the fluid circuits may
comprise vertical coils of differing dimensions. Also, the spacing
between adjacent vertical coils as well as the number of vertical
coils in each fluid circuit may vary.
[0064] Although embodiments have been described above with
reference to the accompanying drawings, those of skill in the art
will appreciate that variations and modifications may be made
without departing from the spirit and scope thereof as defined by
the appended claims.
* * * * *