U.S. patent application number 13/602536 was filed with the patent office on 2014-01-02 for system and method of maximizing performance of a solid-state closed loop well heat exchanger.
The applicant listed for this patent is Michael J. PARRELLA. Invention is credited to Michael J. PARRELLA.
Application Number | 20140000838 13/602536 |
Document ID | / |
Family ID | 42991082 |
Filed Date | 2014-01-02 |
United States Patent
Application |
20140000838 |
Kind Code |
A1 |
PARRELLA; Michael J. |
January 2, 2014 |
SYSTEM AND METHOD OF MAXIMIZING PERFORMANCE OF A SOLID-STATE CLOSED
LOOP WELL HEAT EXCHANGER
Abstract
A heat exchanger transfers heat from solid state heat conducting
material to a fluid in a closed loop system. A heat harnessing
component includes a closed-loop solid state heat extraction system
having a heat exchanging element positioned within a heat nest in a
well designed to optimize the transfer of heat from heat conductive
material to a closed loop fluid flow. A piping system conveys
contents heated by the heat exchanging element to a surface of the
well.
Inventors: |
PARRELLA; Michael J.;
(Weston, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PARRELLA; Michael J. |
Weston |
CT |
US |
|
|
Family ID: |
42991082 |
Appl. No.: |
13/602536 |
Filed: |
September 4, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12462661 |
Aug 5, 2009 |
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13602536 |
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12456434 |
Jun 15, 2009 |
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12462661 |
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61137956 |
Aug 5, 2008 |
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61137974 |
Aug 5, 2008 |
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61137955 |
Aug 5, 2008 |
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61137975 |
Aug 5, 2008 |
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Current U.S.
Class: |
165/45 |
Current CPC
Class: |
F24T 10/10 20180501;
F24T 10/13 20180501; Y02E 10/12 20130101; Y02E 10/10 20130101; F24T
10/30 20180501; F28F 2013/006 20130101; Y02E 10/125 20130101 |
Class at
Publication: |
165/45 |
International
Class: |
F24J 3/08 20060101
F24J003/08 |
Claims
1-10. (canceled)
11. Apparatus, including a heat nest, configured to be positioned
in a bore hole at the bottom of a well for receiving fluid from a
downward-flowing feeder pipe and providing heated fluid to
upward-flowing feeder pipes, comprising: a heat conductive material
and grout configured to fill the bore hole; and a fluid heat
exchanging element configured with multiple pipes having spaces
in-between that are filled with the heat conductive material and
grout, the multiple pipes being configured in relation to one
another to increase the length of the travel path through the heat
conductive material and grout and also to increase the heat
transfer surface area increasing the transfer capability with the
heat conductive material and grout, so the fluid has a longer
period of time to pick up heat from the heat conductive
material.
12. Apparatus according to claim 11, wherein the multiple pipes are
configured as double helix pipes, each pipe having a diameter that
is equal to or greater than the downward and upward flowing feeder
pipes.
13. Apparatus according to claim 11, wherein the twisted nature of
the multiple pipes increases the length of the travel path through
the heat conductive material and also increases the heat transfer
surface area increasing the transfer capability with the heat
conductive material and grout.
14. Apparatus according to claim 11, wherein the twisted nature of
the multiple pipes increases the length of the travel path through
the heat conductive material and also increases the heat transfer
surface area increasing the transfer capability with the heat
conductive material and grout.
15. Apparatus according to claim 11, wherein the multiple pipes are
a collection of smaller heat exchanger pipes, where the sum of the
volume capacity of the smaller heat exchanger pipes is greater than
the volume capacity of the downward and upward flowing feeder
pipes.
16. Apparatus according to claim 15, wherein increased volume of
the smaller heat exchanger pipes slows the fluid flow and increased
surface area of the smaller heat exchanger pipes increases the heat
transfer capability.
17. Apparatus according to claim 15, wherein the smaller diameter
of the smaller heat exchanger pipes is configured to allow more of
the fluid to be exposed to the heat from the heat conductive
material and grout thereby increasing the capability of the
transfer of heat.
18. Apparatus according to claim 15, wherein the larger volume of
the smaller heat exchanger pipes increases the time the fluid
spends within the heat conductive material and grout, and increased
surface area of the smaller heat exchanger pipes and the smaller
diameters increases the heat transfer capability, such that the
increased time allows the fluid a longer time to pick up the heat
from the heat conductive material and grout and the increased
surface area and smaller diameters improves the transfer capability
per linear foot.
19. Apparatus according to claim 15, wherein the fluid heat
exchanging element is configured in modules and the total length is
the sum of attached modules.
20. Apparatus according to claim 19, wherein a last module located
at the bottom of the well has a downward flowing feeder pipe
attached to an upward flowing feeder pipe creating a
U-connection.
21. Apparatus according to claim 15, wherein the fluid heat
exchanging element is configured with a plurality of smaller
capillaries or heat exchanger pipes, so that the fluid enters the
fluid heat exchanging element from at least one downward-flowing
feeder pipe and is dispersed flowing through each of the plurality
of smaller capillaries or heat exchanger pipes.
22. Apparatus according to claim 15, wherein the fluid heat
exchanging element is configured from a titanium clad tube sheet,
including one formed from a high temperature nickel based alloy or
ferritic steel.
23. Apparatus according to claim 22, wherein the thickness of the
titanium clad tube sheet depends on the specific temperature and/or
pressure conditions under which the fluid heat exchanging element
operates.
24. Apparatus according to claim 15, wherein the fluid includes
antifreeze, gas or water.
25. Apparatus according to claim 15, wherein the fluid does not
contain any corrosive properties and the material of the multiple
pipes is substantially resistant to the fluid.
26. Apparatus according to claim 15, wherein the apparatus is
configured so that the fluid is pressurized within the fluid heat
exchanging element
27. Apparatus according to claim 15, wherein the heat conductive
material and grout is configured to bond and solidify within the
well.
28. Apparatus according to claim 15, wherein the fluid heat
exchanging element comprises at least one twisted pipe to increase
the distance and slow the fluid flowing through the fluid heat
exchanging element.
29. Apparatus according to claim 15, wherein the multiple piping
arrangement includes a plurality of capillaries.
30. Apparatus according to claim 29, wherein contents of the
downward-flowing pipe are dispersed through the plurality of
capillaries after entering the multiple piping arrangement.
31. Apparatus according to claim 30, wherein each capillary in the
plurality of capillaries has a diameter smaller than a diameter of
the downward-flowing pipe, thereby allowing the contents of the
apparatus to heat quickly as the contents pass through the
plurality of capillaries.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
Non-Provisional patent application Ser. No. 12/456,434 filed on
Jun. 15, 2009. This application also claims priority to 1) U.S.
Provisional Application No. 61/137,956, filed on Aug. 5, 2008; 2)
U.S. Provisional Application No. 61/137,974, filed on Aug. 5, 2008;
3) U.S. Provisional Application No. 61/137,955, filed on Aug. 5,
2008; and 4) U.S. Provisional Application No. 61/137,975, filed on
Aug. 5, 2008, the contents of all of which are hereby incorporated
in their entirety.
STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM
LISTING COMPACT DISK APPENDIX
[0003] Not applicable.
BACKGROUND OF THE INVENTION
[0004] The present invention relates generally to the field of
converting geothermal energy into electricity. More specifically,
the present invention relates to capturing geothermal heat from
deep within a drilled well and bringing this geothermal heat to the
Earth's surface to generate electricity in an environmentally
friendly process.
[0005] Wells that have been drilled for oil and gas exploration
that are either depleted, or have never produced oil or gas,
usually remain abandoned and/or unused and may eventually be
filled. Such wells were created at a large cost and create an
environmental issue when no longer needed for their initial
use.
[0006] Wells may also be drilled specifically to produce heat.
While there are known geothermal heat/electrical methods and
systems for using the geothermal heat/energy from deep within a
well (in order to produce a heated fluid (liquid or gas) and
generate electricity therefrom), these methods have significant
environmental drawbacks and are usually inefficient in oil and gas
wells due to the depth of such wells.
[0007] More specifically, geothermal heat pump (GHP) systems and
enhanced geothermal systems (EGS) are well known systems in the
prior art for recovering energy from the Earth. In GHP systems,
geothermal heat from the Earth is used to heat a fluid, such as
water, which is then used for heating and cooling. The fluid,
usually water, is actually heated to a point where it is converted
into steam in a process called flash steam conversion, which is
then used to generate electricity. These systems use existing or an
made water reservoirs to carry the heat from deep wells to the
surface. The water used for these systems is extremely harmful to
the environment, as it is full of minerals, is caustic and can
pollute water aquifers. Such deep-well implementations require that
a brine reservoir exists or that a reservoir is built by injecting
huge quantities of water into an injection well, effectively
requiring the use of at least two wells. Both methods require that
polluted dirty water is brought to the surface. In the case of EGS
systems, water injected into a well permeates the Earth as it
travels over rock and other material under the Earth's surface,
becoming polluted, caustic, and dangerous.
[0008] A water-based system for generating heat from a well
presents significant and specific issues. For example, extremely
large quantities of water are often injected into a well. This
water is heated and flows around the inside of the well to become
heated and is then extracted from the well to generate electricity.
This water becomes polluted with minerals and other harmful
substances, often is very caustic, and causes problems such as
seismic instability and disturbance of natural hydrothermal
manifestations. Additionally, there is a high potential for
pollution of surrounding aquifers. This polluted water causes
additional problems, such as depositing minerals and severely
scaling pipes.
[0009] Geothermal energy is present everywhere beneath the Earth's
surface. In general, the temperature of the Earth increases with
increasing depth, from 400.degree.-1800.degree. F. at the base of
the Earth's crust to an estimated temperature of
6300.degree.-8100.degree. F. at the center of the Earth. However,
in order to be useful as a source of energy, it must be accessible
to drilled wells. This increases the cost of drilling associated
with geothermal systems, and the cost increases with increasing
depth.
[0010] In a conventional geothermal system, such as for example and
enhanced geothermal system (EGS), water or a fluid (a liquid or
gas), is pumped into a well using a pump and piping system. The
water then travels over hot rock to a production well and the hot,
dirty water or fluid is transferred to the surface to generate
electricity.
[0011] As mentioned earlier herein, the fluid (water) may actually
be heated to the point where it is converted into gas/steam. The
heated fluid or gas/steam then travels to the surface up and out of
the well. When it reaches the surface, the heated water and/or the
gas/steam is used to power a thermal engine (electric turbine and
generator) which converts the thermal energy from the heated water
or gas/steam into electricity.
[0012] This type of conventional geothermal system is highly
inefficient in very deep wells for several of reasons. First, in
order to generate a heated fluid required to efficiently operate
several thermal engines (electric turbines and generators), the
fluid must be heated to degrees of anywhere between 190.degree. F.
and 1000.degree. F. Therefore the fluid must obtain heat from the
surrounding hot rock. As it picks up heat it also picks up
minerals, salt, and acidity, causing it to very caustic. In order
to reach such desired temperatures in areas that lack a
shallow-depth geothermal heat source (i.e. in order to heat the
fluid to this desired temperature), the well used must be very
deep. In this type of prior art system, the geologies that can be
used because of the need for large quantities of water are very
limited.
[0013] The deeper the well, the more challenging it is to implement
a water-based system. Moreover, as the well becomes deeper the gas
or fluid must travel further to reach the surface, allowing more
heat to dissipate. Therefore, using conventional geothermal
electricity-generating systems can be highly inefficient because
long lengths between the bottom of a well and the surface results
in the loss of heat more quickly. This heat loss impacts the
efficacy and economics of generating electricity from these types
of systems. Even more water is required in such deep wells, making
geothermal electricity-generating systems challenging in deep
wells.
[0014] Accordingly, prior art geothermal systems include a pump, a
piping system buried in the ground, an above ground heat transfer
device and tremendous quantities of water that circulates through
the Earth to pick up heat from the Earth's hot rock. The ground is
used as a heat source to heat the circulating water. An important
factor in determining the feasibility of such a prior art
geothermal system is the depth of wellbore, which affects the
drilling costs, the cost of the pipe and the size of the pump. If
the wellbore has to be drilled to too great a depth, a water-based
geothermal system may not be a practical alternative energy source.
Furthermore, these water-based systems often fail due to a lack of
permeability of hot rock within the Earth, as water injected into
the well never reaches the production well that retrieves the
water.
BRIEF SUMMARY OF THE INVENTION
[0015] Wells that have been drilled for oil and gas exploration
that are either depleted, or have never produced oil or gas, can
now be used to generate electricity. Wells can also be drilled
specifically for the purpose of generating electricity. The only
requirement is that the wells are deep enough to generate heat from
the bottom of the well. The invention is a process for maximizing
the performance of a heat exchanger that resides at the heat zone
of a geothermic system in a well. The heat exchanging mechanism is
a combination of a fluid heat exchanging element 3, heat conductive
material and grout 6. The fluid heat exchanging mechanism maximizes
the heat transfer from the bottom of the well to the surface. The
invention uses a heat exchanger that has a fluid component and a
sold state heat flow component where the solid state heat flow
component transfers heat to the fluid.
[0016] There are pipe(s) carrying the heat conducting fluid into
the fluid heat exchanging mechanism (fluid heat exchanging element
plus heat conductive material and grout) at the bottom of the well
from the surface and pipe(s) carrying the fluid, after being
heated, back to the surface.
[0017] The heat exchanging mechanism needs to be able to enable the
maximum amount of fluid flow while also maximizing the heat
exchange to the fluid.
[0018] The pipe(s) need to minimize heat loss while transporting
the fluid. The volume of fluid that flows through the fluid heat
exchanging element needs to be as high a multiple as possible
compared to the fluid flow of the pipe(s).
[0019] The rate of flow of the fluid in the fluid heat exchanging
element will therefore be decreased by the volume differences
between the pipe and the heat exchanger element. By slowing down
the fluid flow in the fluid heat exchanging element you increase
the time the fluid is exposed to the heat conductive material and
grout in the heat zone and increase the heat that is transferred to
the fluid. This allows the heat conductive material and grout part
of the heat exchanging mechanism time to conduct and transfer the
heat to the fluid. A standard heat exchanger transfers the heat
from one fluid to another. The following embodiments transfer a
solid state heat flow to a fluid.
[0020] Other embodiments, features and advantages of the present
invention will become more apparent from the following description
of the embodiments, taken together with the accompanying several
views of the drawings, which illustrate, by way of example, the
principles of the invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0021] FIG. 1 is a conceptual view of a system according to one
embodiment of the present invention showing a fluid heat exchanging
element having a much larger diameter than the feeder pipes;
[0022] FIG. 2 is a conceptual view of a system according to another
embodiment of the present invention showing a double helix design
of the fluid heat exchanging element;
[0023] FIG. 3 is a conceptual view of a system according to another
embodiment of the present invention showing the fluid heat
exchanging element as a collection of smaller heat exchanger pipes
where the sum of the volume capacity of the pipes is greater than
the volume capacity of the feeder pipes;
[0024] FIG. 4 is a conceptual view of a system according to another
embodiment of the present invention showing the fluid heat
exchanging element built in modules having a total length that is
the sum of the modules; and
[0025] FIG. 5 is a cross-sectional, conceptual view of pipes
according to one embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0026] In the following description of the present invention
reference is made to the accompanying drawings which form a part
thereof, and in which is shown, by way of illustration, exemplary
embodiments illustrating the principles of the present invention
and how it may be practiced. It is to be understood that other
embodiments may he utilized to practice the present invention and
structural and functional changes may be made thereto without
departing from the scope of the present invention.
[0027] FIG. 1 illustrates a first preferred embodiment for the
fluid heat exchanging element 3 where the element has a much larger
diameter then the feeder pipes 2. The larger diameter slows the
rate of flow of the fluid while it flows through the heat nest 10
portion of the system. The slower flow characteristics allow the
fluid a longer time to pick up the heat from the heat conductive
material and grout 6. The fluid travels down and up of the fluid
heat exchanging element picking up heat;
[0028] FIG. 2 illustrates a second preferred embodiment for the
fluid heat exchanging element 3 where the element is a double helix
design. The double helix pipes have an equal or larger diameter
than the feeder pipes and the twisted nature of the pipes increase
the length of the travel path within the heat nest 10. The
increased travel path (and the lager diameter if present) increase
the time the fluid spends within the heat nest 10 portion of the
system and the twisted pipe arrangement increases the heat transfer
surface area increasing the transfer capability. The increased time
allows the fluid a longer time to pick up the heat from the heat
conductive material and grout 6 and the increased surface area
increase the transfer capacity. The fluid travels down and up of
the fluid heat exchanging element picking up heat;
[0029] FIG. 3 illustrates a third preferred embodiment for the
fluid heat exchanging element 3 where the element is a collection
of smaller heat exchanger pipes 4 where the sum of the volume
capacity of the pipes is greater than the volume capacity of the
feeder pipes 2. The increased volume of the heat exchanger pipes
slows the fluid flow and the increased surface area of the pipes
(versus a single pipe) increases the heat transfer capability. The
smaller diametr of the pipes allows more of the fluid to be exposed
to the heat thereby increasing the capability of the transfer of
heat. The larger volume of the heat exchanger pipes increase the
time the fluid spends within the heat nest 10 portion of the system
and the increased surface area of he pipe surface increases and the
smaller diameters increases the heat transfer capability. The
increased time allows the fluid a longer time to pick up the heat
from the heat conductive material and grout 6 and the increased
surface area and smaller diameters improves the transfer capability
per linear foot. The fluid travels down and up of the fluid heat
exchanging element picking up heat;
[0030] FIG. 4 illustrates an embodiment of the fluid heat
exchanging element where the element cart be built in modules and
the total length is the sum of the attached modules. The last
module (FIG. 3) located at the bottom of the well has the downward
flowing feeder pipe attached to the upward flowing feeder pipe
creating a U-connection. As an example if the fluid heat exchanging
element needed to be 500 feet long we can build it by connecting
twenty five (25) twenty foot (20) modules. The module
implementation can be accomplished regardless of the design of the
heat exchanging element.
[0031] Each of the preferred embodiments is designed to maximize
the exchange of heat from a solid state heat flow environment (heat
conductive material and grout 6) to a fluid environment. This is
accomplished by designing a fluid heat exchanging element that
accomplishes one or more of the following functions: [0032] 1.
Increases the fluid volume capacity of the heat exchanging element
compared to the volume capacity of the feeder pipes. This increases
the time the fluid spends in the heat nest thereby increasing the
amount of heat that can be transferred; [0033] 2. Increase the
surface area of the fluid heat exchanging element thereby
increasing the linear capacity to exchange heat; [0034] 3.
Modularize the design so the fluid heat exchanging element can be
as long as required; [0035] 4. Decrease the diameter of the heat
exchanging pipes allowing more of the fluid to touch the heat
exchanging surface of the pipe; [0036] 5. Use heat conductive
material and gout instead of a fluid to conduct heat from the hot
rock to the heat exchanging element; [0037] 6. Use flexible
connectors to attached the fluid heat exchanging modules together.
These flexible connectors will provide a level of protection
against earth movement, tremors and earth quakes; [0038] 7. The
heat exchanger must fit into the bore hole of a well.
[0039] Referring now to FIG. 1, there is shown a preferred
embodiment for the heat exchanging element 3 utilized in the
present invention. Heat exchanging elements are devices built for
efficient heat transfer which typically transfer heat or one fluid
to another. They are widely used in many engineering processes.
Some examples include intercoolers, pre-heaters, boilers and
condensers in power plants. By applying the first law of
thermodynamics to a heat exchanger working at steady-state
condition, we obtain:
mi hi=0
where,
[0040] mi=mass flow of the i-th fluid
[0041] hi=change of specific enthalpy of the i-th fluid
[0042] In a preferred embodiment, the heat exchanging element
utilized in the present invention is a high-temperature heat
exchanger ("HTHE") comprised of a recuperative type "cross flow"
heat exchanger, in which a fluid exchanges heat with a solid state
heat flow on either side of a dividing wall. Alternatively, the
heat exchange element may be comprised of an HTHE which utilizes a
regenerative and/or evaporative design. The embodiments of the
invention replace one of the fluids with a solid state heat
flow.
[0043] In a preferred embodiment FIG. 3, the heat exchanger will
have a plurality of smaller capillaries (heat exchanger pipes 5).
The fluid enters the heat exchanger from the downward flowing
feeder pipe(s) 2, where it is then dispersed, flowing through each
of the plurality of smaller capillaries. Preferably the capillaries
are thinner (having a smaller diameter than the downward flowing
pipe(s), thereby allowing the fluid to beat more quickly as it
passes through the capillaries--increasing the overall efficacy of
the heat exchanger. In a preferred embodiment, the combined flow of
the capillaries of the heat exchanging element must be able to
accommodate an equal or greater flow then the downward and upward
flow pipe(s). This greater flow increases the time the fluid spends
in the heat exchanger.
[0044] In a preferred embodiment, the heat exchanging element may
be comprised from a titanium clad tube sheet, wherein the tube
sheet may be formed from a high temperature nickel based alloy or
ferritic steel. In this way, the heat exchanger is able to operate
efficiently under high temperature/pressure conditions. Moreover,
the thickness of the titantium may vary in accordance with specific
temperature and/or pressure conditions under which the heat
exchange element operates.
[0045] It is understood that there are other types of heat
exchanging elements known the art which may also be used in the
present invention such as parallel heat exchangers and/or reverse
flow heat exchangers. In alternative embodiments, any of these
types of exchangers may be utilized. A primary consideration in
designing the heat exchanging element will be to ensure its
efficient operation under high temperature/pressure conditions.
Further, any such heat exchanger utilized in the present invention
must be sized to fit within the bore hole of the well.
[0046] Still referring to FIG. 1, the upward flowing feeder pipe(s)
2 of the piping system are preferably coupled to the heat
exchanging element 3 on an opposite side of the element. The upward
flowing pipe(s) 2 draw the heated fluid from the heat exchanging
element 3 and bring the heated fluid upward from the "heat point"
in the well to the top surface.
[0047] In a preferred embodiment, the fluid that is used should be
optimized to carry heat. An example of such a fluid is the
antifreeze used in automobiles. Gas or water can also be used as a
fluid. Further, the fluid cannot and should not have any corrosive
properties and the piping material needs to be resistant to the
fluid. Moreover, the fluid will be pressurized within the piping
system so the system should be able to withstand the pressure
generated by the depth of the well and the pumping mechanism, as
the fluid is pumped through the system.
[0048] Referring still to FIG. 1, once the piping and heat
exchanging element are fully installed in the well, the well is
completely filled with a heat conductive material and grout 6. The
heat conductive material and grout 6 must have heat conductive
properties and preferably will bond and solidify within the well.
In the preferred embodiment wherein the well is insulated, the heat
exchanging element will be lowered into the well and then the heat
conductive material and the grout will be inserted into the well
before the insulation.
[0049] It is to be understood that other embodiments may be
utilized and structural and functional changes me be made without
departing from the scope of the present invention. The foregoing
descriptions of the embodiments of the invention have been
presented for the purposes of illustration and description. It is
not intended to be exhaustive or to limit the invention to the
precise forms disclosed. Accordingly, many modifications and
variations are possible in light of the above teachings. It is
therefore intended that the scope of the invention not be limited
by this detailed description.
* * * * *