U.S. patent application number 12/504240 was filed with the patent office on 2010-02-18 for geothermal hybrid heat exchange system.
Invention is credited to James R. Johnson, Jason R. Johnson.
Application Number | 20100038052 12/504240 |
Document ID | / |
Family ID | 41680457 |
Filed Date | 2010-02-18 |
United States Patent
Application |
20100038052 |
Kind Code |
A1 |
Johnson; James R. ; et
al. |
February 18, 2010 |
GEOTHERMAL HYBRID HEAT EXCHANGE SYSTEM
Abstract
A geothermal hybrid heat exchange system is provided. The system
includes a heat pump having a first fluid port and a second fluid
port, a fluid reservoir, and at least one earth loop. A first end
of the earth loop is connected to the first fluid port of the heat
pump and the second fluid port of the heat pump and the second end
of the earth loop are coupled in fluid communication with the
reservoir so that fluid in the reservoir passes through the earth
loop and the heat pump during heating/cooling operation of the heat
pump.
Inventors: |
Johnson; James R.;
(Chandler, AZ) ; Johnson; Jason R.; (Spokane,
WA) |
Correspondence
Address: |
ROBERT A. PARSONS
4000 N. CENTRAL AVENUE, SUITE 1220
PHOENIX
AZ
85012
US
|
Family ID: |
41680457 |
Appl. No.: |
12/504240 |
Filed: |
July 16, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61081202 |
Jul 16, 2008 |
|
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Current U.S.
Class: |
165/45 |
Current CPC
Class: |
F24T 10/30 20180501;
F24T 10/10 20180501; Y02E 10/10 20130101 |
Class at
Publication: |
165/45 |
International
Class: |
F24J 3/08 20060101
F24J003/08 |
Claims
1. A geothermal hybrid heat exchange system comprising: a heat pump
having a first fluid port and a second fluid port; a fluid
reservoir; and at least one earth loop having first and second
ends, the first end being connected to the first fluid port of the
heat pump, and the second fluid port of the heat pump and the
second end of the at least one earth loop coupled in fluid
communication with the reservoir so that fluid in the reservoir
passes through the earth loop and the heat pump during
heating/cooling operation of the heat pump.
2. A geothermal hybrid heat exchange system as claimed in claim 1
wherein the reservoir is a relatively large underground tank.
3. A geothermal hybrid heat exchange system as claimed in claim 2
wherein the relatively large underground tank has a fluid capacity
ten times the fluid capacity of the heat pump and the earth loop or
more.
4. A geothermal hybrid heat exchange system as claimed in claim 1
further including a circulating pump coupled to circulate fluid
from the reservoir through the earth loop when the heat pump is not
operating.
5. A geothermal hybrid heat exchange system as claimed in claim 4
wherein the circulating pump is a component of the heat pump.
6. A geothermal hybrid heat exchange system as claimed in claim 1
wherein the reservoir further includes a fresh fluid inlet and a
hot/cold saturated fluid outlet.
7. A geothermal hybrid heat exchange system as claimed in claim 6
wherein the reservoir further includes a flow of fresh fluid into
the inlet of the reservoir and a flow of hot/cold saturated fluid
through the fluid outlet of the reservoir controlled by a sensor
and a circulating pump.
8. A geothermal hybrid heat exchange system comprising: a heat pump
having a first fluid port and a second fluid port, the heat pump
including heating and cooling operations; a relatively large
underground fluid reservoir; at least one earth loop having first
and second ends, the first end being connected to the first fluid
port of the heat pump, and the second fluid port of the heat pump
and the second end of the at least one earth loop coupled in fluid
communication with the reservoir so that fluid in the reservoir
passes through the earth loop and the heat pump during
heating/cooling operations of the heat pump; and a circulating pump
coupled to circulate fluid from the reservoir through the earth
loop when the heat pump is not operating.
9. A geothermal hybrid heat exchange system as claimed in claim 8
wherein the circulating pump is a component of the heat pump.
10. A geothermal hybrid heat exchange system as claimed in claim 8
wherein the reservoir further includes a fresh fluid inlet and a
hot/cold saturated fluid outlet.
11. A geothermal hybrid heat exchange system as claimed in claim 10
wherein the reservoir further includes a flow of fresh fluid into
the inlet of the reservoir and a flow of hot/cold saturated fluid
through the fluid outlet of the reservoir controlled by a sensor
and a circulating pump.
12. A method of heating/cooling an area comprising the steps of:
providing a heat pump including a heat exchanger situated within
the area to be heated/cooled, a relatively large underground fluid
reservoir, and at least one earth loop; filling the heat pump, the
earth loop, and the reservoir to capacity with a fluid; circulating
the fluid from the reservoir through the heat pump and the at least
one earth loop during heating/cooling operation.
13. A method as claimed in claim 12 including the steps of
circulating the fluid from the reservoir through the heat pump and
the at least one earth loop at a high rate during heating/cooling
operation and circulating the fluid from the reservoir through the
at least one earth loop at a lower rate during non-heating/cooling
operation.
14. A method as claimed in claim 12 including a step of providing a
circulating pump and connecting the circulating pump to circulate
fluid from the reservoir through the earth loop, and further
connecting the circulating pump to operate when the heat pump is
not operating so as to utilize the reservoir as a heat sink.
15. A method as claimed in claim 12 including a step of providing a
fluid inlet to the reservoir and coupling the fluid inlet to a
source of fresh fluid, providing a saturated fluid outlet from the
reservoir and coupling the saturated fluid outlet to a fluid
disposal, and introducing fresh fluid from the fluid inlet to the
reservoir and removing saturated fluid from the reservoir through
the saturated fluid outlet when the fluid in the reservoir has
reached a saturated state.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/081,202, filed 16 July 2008.
FIELD OF THE INVENTION
[0002] This invention generally relates to a geothermal heat
exchange system and more specifically to a hybrid heat exchange
system.
BACKGROUND OF THE INVENTION
[0003] Geothermal heating/cooling systems utilize the constant
temperature of the earth to provide heating in the winter and
cooling in the summer. Geothermal heating/cooling systems can
greatly reduce consumption of electricity, natural gas, propane, or
heating oil, typically by one third or more. This reduction in
carbon based energy results in a decrease in pollution and
dependence on foreign oil. Though widespread experience has shown
geothermal systems do save money, much of the market place has not
embraced the technology. Were geothermal systems better accepted,
not only would the users reap monetary benefit, but our environment
and our economy would be enhanced by their use. The majority of new
homes constructed could benefit from a geothermal system, but
though use is increasing, significant numbers of users are lacking.
This lack of use can be attributed to several factors. There is
little promotion or advertising of such systems and there is very
little detailed system information available, except for the
geothermal heat pump itself. Manufacturers of geothermal heat pumps
provide volumes of information pertinent to their equipment, but
the heat pump is just one component of a system. Very little
information can be found as to ground-to-line btu transfer rates,
btu rates for heating versus cooling, etc. Several other major
factors influence potential purchasers, such as cost, land space
required, water supply, pump size requirements, and operating
pressures.
[0004] There are other valid reasons many have not installed
geothermal heating/cooling systems. Many property owners either
cannot afford the installation cost or have property space
restrictions that will not accommodate closed loop systems. Some
property owners do not have adequate well water available for an
open loop system, or local regulation does not allow injecting
return water back down into the ground water. Other property owners
are not comfortable with geothermal systems as they recognize
ground source systems do have limitations and are concerned with
consequences once a system has reached those limitations. To
accommodate those limitations typically a secondary heating and/or
cooling system is installed. Natural gas, propane, electricity, or
heating oil usually powers the secondary backup system.
[0005] An open loop system is fairly simple. Water is pumped out of
a ground source well at approximately 15 gallons per minute
(g.p.m.), introduced into and through a heat pump where heat or
cold is extracted from the water. The water then passes out of the
heat pump, approximately 10 degrees colder or warmer than it was
when it entered the heat pump, and is injected back into either the
well it came from or into a second well or it enters some other
use, such as irrigation. Some locales do not allow water to be
injected back down into the ground water, possibly due to
contamination issues due to the decrease or increase in
temperature. The volume of water can be substantial. As an example,
if the heat pump operates for 20 minutes, then 300 gallons of water
must be both pumped from the ground and then disposed of. Pump
operation can be expensive and, due to the high volume of water
being pumped, pump maintenance can be another expense. A large
percentage of properties do not have the required capability for
this type system.
[0006] A closed loop system is somewhat more complicated and has a
significantly higher cost. In a closed loop system the heat pump
either extracts heat from within a closed loop or passes heat to
the closed loop when in the cooling mode. Water (or other
convenient liquid) is pumped through a ground loop, similar to a
radiator, made up of high density polyethylene pipe (HDPE), which
is buried in the ground. Much as air cools the water in a radiator,
the constant temperature of the ground either heats or cools the
water inside the closed HDPE loop. Typically, one closed loop is
used for every ton capacity of the heat pump. For example, a 5 ton
heat pump uses 5 closed loops and a 7 ton unit uses 7 closed loops.
These multiple loops are connected to the heat pump by means of a
manifold. These loops typically operate at a fairly high pressure
and at a high flow volume. Both pressure and flow volume are
adjusted for the individual system. When closed loops are utilized
cost becomes a major factor. Space also becomes a factor as the
typical individual loop requires a 3 foot wide trench for
installation plus 30 inches of ground space on each side for
adequate ground contact to perform the heat transfer. The average
closed loop requires about 800 square foot of surface area. These
loops most commonly consist of 600 foot of 3/4 inch HDPE pipe
installed in a 3 foot by 100 foot trench. This plastic pipe is
generally installed in loops, like a Slinky toy, in such a way as
each successive loop is 3 foot in diameter and overlaps the
previous loop by about 18 inches. In this manner, 600 foot of pipe
is installed in 100 foot of trench. A standard 5 ton system
requires a surface area of approximately 4,000 square feet. A 7 ton
system requires approximately 5,600 square feet. A closed loop
system has a limitation in that if the water within the loop is
cooled faster than the ground will heat it, then the heat pump
stops generating heat. In reverse, if the water is heated by the
heat pump faster than the ground will cool it, the heat pump stops
providing cooling capacity. Another factor in the closed loop
system is that the water is only pumped through the loops when the
heat pump is operating.
[0007] A somewhat modified closed loop system is disclosed in U.S.
Pat. No. 4,257,239, entitled "Earth Coil Heating and Cooling
System", issued Mar. 24, 1981. In this system the compressor and
evaporator of the heat pump are separated with one acting as a
compressor and the other acting as an evaporator during one mode of
operation and a switch is included to reverse the operation in a
second mode.
[0008] A somewhat modified closed loop system is disclosed in U.S.
Pat. Nos. 2,529,154 and 2,689,090, both entitled "Heating System",
and issued Nov. 7, 1950 and Sep. 14, 1954, respectively. In this
system an additional loop is included and positioned in the air or
sunshine to compensate for undue ground cooling. Thus, basically a
solar heater is included to compensate for periods when the ground
is too cool.
[0009] It would be highly advantageous, therefore, to remedy the
foregoing and other deficiencies inherent in the prior art.
[0010] Accordingly, it is an object of the present invention to
provide a new and improved geothermal hybrid heating/cooling
system.
[0011] Another object of the invention is to provide a new and
improved geothermal hybrid heating/cooling system that is less
expensive to install and to maintain.
[0012] Another object of the invention is to provide a new and
improved geothermal hybrid heating/cooling system that is more
efficient and requires less space.
[0013] Another object of the invention is to provide a new and
improved geothermal hybrid heating/cooling system that offers
increased capacity.
[0014] Another object of the invention is to provide a new and
improved geothermal hybrid heating/cooling system that can be
utilized to retrofit existing geothermal systems for increased
capacity.
[0015] Another object of the invention is to provide a new and
improved geothermal hybrid heating/cooling system that allows solar
heating panels to be employed in conjunction to the closed
loops.
SUMMARY OF THE INVENTION
[0016] Briefly, to achieve the desired objects of the instant
invention in accordance with a preferred embodiment thereof, a
novel geothermal hybrid heat exchange system is provided. The
system includes a heat pump having a first fluid port and a second
fluid port, a fluid reservoir, and at least one earth loop. A first
end of the earth loop is connected to the first fluid port of the
heat pump and the second fluid port of the heat pump and the second
end of the earth loop are coupled in fluid communication with the
reservoir so that fluid in the reservoir passes through the earth
loop and the heat pump during heating/cooling operation of the heat
pump.
[0017] In a specific embodiment of the present invention, the
geothermal hybrid heat exchange system includes a heat pump, a
relatively large underground fluid reservoir, and at least one
earth loop. A first end of the earth loop is connected to the first
fluid port of the heat pump and the second fluid port of the heat
pump and the second end of the earth loop are coupled in fluid
communication with the reservoir so that fluid in the reservoir
passes through the earth loop and the heat pump during
heating/cooling operation of the heat pump. In this embodiment the
system further includes a circulating pump coupled to circulate
fluid from the reservoir through the earth loop when the heat pump
is not operating so that the reservoir operates like a heat sink
and absorbs excess heat or cold from the fluid.
[0018] A specific method of the present invention includes the
steps of providing a heat pump with a heat exchanger situated
within an area to be heated/cooled and providing a relatively large
underground fluid reservoir and at least one earth loop. The method
then includes the steps of filling the heat pump, the earth loop,
and the reservoir to capacity with a fluid and circulating the
fluid from the reservoir through the heat pump and the at least one
earth loop during heating/cooling operation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The foregoing and further and more specific objects and
advantages of the instant invention will become readily apparent to
those skilled in the art from the following detailed description of
a preferred embodiment thereof taken in conjunction with the
drawings in which:
[0020] FIG.1 illustrates a simplified schematic view of a
geothermal hybrid heating/cooling system in accordance with the
present invention;
[0021] FIG. 2 illustrates a simplified schematic view of another
embodiment of a geothermal hybrid heating/cooling system in
accordance with the present invention; and
[0022] FIG. 3 illustrates a simplified schematic view of another
embodiment of a geothermal hybrid heating/cooling system in
accordance with the present invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0023] Heat pumps, sometimes referred to as reverse cycle
refrigeration units, are well known in the art. Basically, heat
pumps include a compressor, an expansion valve, and two heat
exchangers with one heat exchanger positioned within the enclosure
to be heated/cooled and the other heat exchanger positioned
outside. In the heating mode, for example, the inside heat
exchanger operates as a condenser and is positioned to heat the air
in the enclosure while the outside heat exchanger operates as an
evaporator and is positioned to absorb heat from the low grade heat
source (generally the atmosphere). In the cooling mode the system
is switched so that the inside heat exchanger operates as an
evaporator and is positioned to cool the air in the enclosure while
the outside heat exchanger operates as a condenser and is
positioned to transfer heat to the low grade cooling source
[0024] In, for example, a geothermal closed loop system the heat
pump operates the same as described above but fluid circulating
through the heat pump, or a portion of the heat pump, is circulated
through one or more closed loops positioned to take advantage of
the relatively constant temperature of the ground or earth
(hereinafter an "earth loop"). It will be understood that the fluid
circulating through the closed loop preferably heats or cools fluid
within the heat pump itself by means of a heat exchanger but could
in some specific applications actually be circulated through the
heat exchangers of the heat pump as the sole driving fluid. Either
or both of these configurations are included in the description of
a heat pump in the following disclosure.
[0025] Turning now to FIG. 1, a simplified drawing is illustrated
of a geothermal hybrid heating/cooling system 10 in accordance with
the present invention. System 10 includes a heat pump 12, which may
be a heat pump as described above or some modification thereof, and
which includes two inlet/outlet liquid ports 14 and 16. System 10
also includes one or more earth loops 18 having one end in fluid
communication with liquid port 14 of heat pump 12. The other end of
earth loops 18 is positioned in communication with a liquid 20 in a
reservoir 22. As understood in the geothermal heating/cooling art,
earth loops 18 are positioned in the ground in a relatively
constant temperature position. Reservoir 22 will generally be a
relatively large underground tank positioned to take advantage of
the substantially constant temperature of the ground or earth. As
an example, reservoir 22 will have a capacity many times more than
the capacity of the system without the reservoir (i.e. the fluid
capacity of heat pump 12 and earth loop 18). Thus, not only does
the earth insulate liquid 20 in reservoir 22 from the fluctuations
of the atmosphere but it also protects and maintains the
temperature relatively constant.
[0026] Second liquid port 16 of heat pump 12 is connected in liquid
communication with liquid 20 in reservoir 22 to complete the
circuit. Thus, as liquid 20 is pumped from reservoir 22 through
earth loops 18, it is returned to reservoir 22 by way of port 16
and vice versa. It will of course be understood that additional
earth loops (similar to loops 18 and either in series or in
parallel with loops 18) could be included in the line from
reservoir 22 to port 14, if desired and convenient. Also, while
reservoir 22 is described as `large`, it will be understood that
the size will generally be determined by the size and capacity of
system 10. For example, the reservoir of a two ton system might be
at least twice as large as the reservoir for a one ton system.
[0027] Thus, in operation, water (or other convenient liquid) is
stored generally underground in reservoir 22. Heat pump 12 is
supplied with water from reservoir 22. The water is circulated
through heat pump 12 and earth loops 18, which provide heating or
cooling of the water, and is then returned to reservoir 22. The
relatively large volume of water in reservoir 22 acts as a heat
sink and absorbs any excess cold or heat from the water. The heat
sink action of reservoir 22 allows excess btu transfer from heating
at night (for example) to be absorbed by the water volume contained
in reservoir 22 and disbursed later at off peak hours during the
day. The opposite occurs when cooling is performed. The hot water
is dumped into reservoir 22 and the heat is absorbed allowing it to
be disbursed during off peak hours at night.
[0028] Reservoir 22 further allows water to be circulated
constantly through loops 18, providing additional operating time
for the ground to either heat or cool the water within loops 18. It
will be understood that a lower circulating pressure or flow might
be conveniently utilized during off times (i.e. non-heating/cooling
operation) for heat pump 12 if desired. As an example of this
structure, a control box 24 is electrically and physically attached
to heat pump 12 to provide it with different circulating pressures
or flows, e.g. a heating/cooling operation and a setting in which
fluid is simply pumped from port 14 to port 16 or vice versa.
[0029] Referring to FIG. 2, a simplified drawing is illustrated of
another embodiment of a geothermal hybrid heating/cooling system
200 in accordance with the present invention. System 200 includes a
heat pump 212, which may be a heat pump as described above, or some
modification thereof, and which includes two inlet/outlet liquid
ports 214 and 216. System 200 also includes one or more earth loops
218 having one end in fluid communication with liquid port 214 of
heat pump 212. The other end of loops 218 is positioned in
communication with a liquid 220 in a reservoir 222. In this
specific example, a smaller circulating pump 224 is included in the
system fluid circuit and activated when heat pump 212 is
deactivated (i.e. between heating/cooling operation). By utilizing
reservoir 222 and constant circulation, fewer loops 218 are
required in any specific system, thereby reducing the space
required and the cost.
[0030] Referring to FIG. 3, a simplified drawing is illustrated of
another embodiment of a geothermal hybrid heating/cooling system
300 in accordance with the present invention. System 300 includes a
heat pump 312, which may be a heat pump as described above, or some
modification thereof, and which includes two inlet/outlet liquid
ports 314 and 316. System 300 also includes one or more earth loops
318 having one end in fluid communication with liquid port 314 of
heat pump 312. The other end of loops 318 is positioned in
communication with a liquid 320 in a reservoir 322. In this
specific example, reservoir 322 also includes a water inlet 324
with a control valve 326 and a pump 328 connected to a water outlet
330. It will be understood that control valve 326 and pump 328
operate together and in conjunction with a sensor 332 in reservoir
320 or a sensor associated with heat pump 312. Alternatively, pump
224 (see FIG. 2) providing constant circulation or the pump in heat
pump 312 can conveniently be connected to pump water from reservoir
322 through water outlet 330 to an external destination. If an
operating temperature limit is reached (i.e. a saturation point),
then hot or cold saturated water 320 is pumped out of reservoir 322
by way of water outlet 328 and reservoir 322 is refilled with fresh
water by way of water inlet 324 coupled to some convenient source,
such as municipal water, well water, etc. This feature overcomes
the limitation factor commonly associated with a closed loop
system.
[0031] Other methods of dealing with hot or cold saturated water in
the reservoir are also contemplated. These methods include using
auxiliary heating systems to heat the water in the reservoir if it
becomes cold saturated. These auxiliary systems can include solar
water heating panels which can heat water stored in the reservoir,
or even gas or electric water heaters if necessary. In these
instances, instead of using a pump to dump water, the water from
the reservoir is run through, for example, solar heating panels and
returned to the reservoir.
[0032] Thus, a new and improved geothermal hybrid heating/cooling
system is disclosed. The new system overcomes many limitations
commonly associated with standard closed loop systems. The new and
improved geothermal hybrid heating/cooling system provides at least
the following benefits: the ground space requirement is reduced by
almost 50%; the cost of ground loops and installation are reduced
by about 40%, overall efficiency is improved and the hybrid system
provides for backup operation should the limitation point be
reached, which reduces dependency on a secondary backup system.
[0033] Various changes and modifications to the embodiment herein
chosen for purposes of illustration will readily occur to those
skilled in the art. To the extent that such modifications and
variations do not depart from the spirit of the invention, they are
intended to be included within the scope thereof which is assessed
only by a fair interpretation of the following claims.
[0034] Having fully described the invention in such clear and
concise terms as to enable those skilled in the art to understand
and practice the same, the invention claimed is:
* * * * *