METHOD OF HEAT EXCHANGE SYSTEM
A method for heat exchange with a heat transfer medium including providing a ground loop circuit through which the heat transfer medium is circulatable. The circuit includes an end portion, positioned proximal to a heat exchanger, one or more pipe portions having embedded parts thereof positioned in pipe bodies. Each pipe body defines a conduit therein through which a fluid is flowable, and has an exterior surface engaged with ground material. The method also includes circulating the heat transfer medium through the ground loop circuit, to permit heat transfer between the heat transfer medium moving through the embedded part and the fluid in the conduit, and heat transfer between the heat transfer medium moving through the embedded part and the ground material engaged with the pipe body.
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This is a divisional of co-pending application Ser. No. 12/728,366, filed on Mar. 22, 2010, which claims the benefit of U.S. Provisional Patent Application No. 61/161,948, filed Mar. 20, 2009, each of which prior application is incorporated herein in its entirety by reference.
FIELD OF THE INVENTIONThe present invention is a method of heat exchange in which a heat transfer medium is circulated through a circuit for heat exchange with fluid flowing through a pipe buried in ground material, and for heat exchange with the ground material.
BACKGROUND OF THE INVENTIONHeat pumps, and in particular geothermal heat pumps, are well known in the art. In general, geothermal heat pumps are adapted to draw energy from shallow ground, i.e., energy from the sun which is stored in the ground. The shallow ground is used as a heat source (i.e., when the heat pump is used to provide heat to an indoor space in a building), or a heat sink (i.e., when the heat pump is operating to cool the indoor space), as is known.
Various geothermal heat pump systems are known. However, the known heat pump systems have a number of disadvantages. In particular, only the shallow ground is used as a heat source or a heat sink, in the typical geothermal heat system.
SUMMARY OF THE INVENTIONThere is a need for a method of heat exchange that overcomes or mitigates one or more of the disadvantages or defects of the prior art. Such disadvantages or defects are not necessarily included in those listed above.
In its broad aspect, the invention provides a method of heat exchange with a heat transfer medium including providing a heat pump assembly for controlling an indoor fluid's temperature with a heat exchanger having a heat exchange fluid circulatable therein, and providing one or more end portions of a ground loop circuit through which the heat transfer medium is circulatable. Each end portion is positioned proximal to the heat exchanger for heat exchange between the heat transfer medium moving through the end portion and the heat exchange fluid moving through the heat exchanger. One or more pipe bodies are provided, each including a substantially cylindrical main portion including a pipe wall defining a conduit therein in which a fluid is receivable. Each pipe body includes an exterior surface adapted for engagement with ground material surrounding the pipe body. One or more pipe portions of the ground loop circuit through which the heat transfer medium is movable are also provided. Each pipe portion includes an embedded part thereof positioned in the pipe wall of the pipe body. In addition, one or more connecting portions connecting the pipe portion(s) and the end portion(s) together are provided, to permit the heat transfer medium to circulate between the end portion(s) and the pipe portion(s). The connecting portion(s) are engaged with ground material in which they are at least partially buried. The heat transfer medium is circulated through the ground loop circuit. Heat transfer is permitted between the heat transfer medium in the embedded part and the fluid in the conduit. Heat is also permitted transfer between the heat transfer medium in the embedded part and the ground material surrounding the pipe body.
In another aspect, the invention provides a method of heat exchange with a heat transfer medium including moving the heat transfer medium through one or more pipe portions of a ground loop circuit. Each pipe portion includes an embedded part thereof positioned in a pipe wall of at least one pipe body defining at least one conduit therein through which a fluid is flowable, each pipe body including an exterior surface engaged with ground material surrounding the pipe body. Substantially simultaneous heat exchange is permitted through the pipe wall between: (i) the heat transfer medium and the fluid in the conduit as the heat transfer medium moves through the embedded part of the pipe portion, and (ii) the heat transfer medium and the pipe ground material as the heat transfer medium moves through the embedded part of the pipe portion. The heat transfer medium is moved through an end portion of the ground loop circuit positioned proximal to a heat exchanger with a heat exchange fluid circulated therein. Heat exchange is also permitted between the heat transfer medium and the heat exchange fluid as the heat transfer medium flows through the end portion. The heat transfer medium is moved through the connecting portion(s) of the ground loop circuit in fluid communication with the pipe portion(s) and with the end portion to allow the heat transfer medium to circulate through the ground loop circuit.
In another of its aspects, the invention provides a method for heat exchange with a heat transfer medium including providing a ground loop circuit through which the heat transfer medium is circulatable. The ground loop circuit includes an end portion, positioned proximal to a heat exchanger through which a heat exchange fluid is circulatable, and one or more pipe portions, each having an embedded part positioned in a pipe wall of a pipe body. Each pipe body defines a conduit therein through which a fluid is flowable, and has an exterior surface engaged with ground material. The ground loop circuit also includes one or more connecting portions connecting the end portion and the pipe portion(s). Each connecting portion engages the ground material. The heat transfer medium is circulated through the ground loop circuit, to permit heat transfer between the heat transfer medium moving through the end portion and the heat exchange fluid; heat transfer between the heat transfer medium moving through the embedded part and the fluid in the conduit; heat transfer between the heat transfer medium moving through the embedded part(s) and the ground material engaged with the pipe body; and heat transfer between the heat transfer medium moving through the connecting portion(s) to the end portion and the ground material engaged with the connecting portion(s).
The invention will be better understood with reference to the drawings, in which:
In the attached drawings, like reference numerals designate corresponding elements throughout. Reference is first made to
In one embodiment, each connecting portion 48 preferably is at least partially engaged with the ground material 36 for heat exchange between the ground material and the heat exchange medium in the connecting portion 48.
As shown in
As illustrated in
The conduit in the pipe body preferably is for channelling waste water, i.e., the pipe body preferably is a sewer pipe. The fluid in the conduit is waste water, which may include in fact various liquids and solids. For instance, the sewer pipe may be part of a sanitary sewer or a storm sewer system. As with relatively shallow ground material, the waste water typically is relatively warm in winter and relatively cool in summer (i.e., compared to ambient air), and the temperature differences are exploited in the invention. In summary, depending on (i) the temperatures of the ground material and the fluid in the conduit and (ii) the results intended to be achieved via controlling the indoor fluid's temperature, heat may be transferred to the heat exchange fluid in the heat exchanger from the heat exchange medium in the end portion (i.e., the ground material and the fluid may be used as heat sources), or alternatively, heat may be exchanged from the heat exchange fluid in the heat exchanger to the heat exchange medium in the end portion (i.e., the ground material and the fluid may be used as heat sinks). It will be appreciated by those skilled in the art that the pip body is not necessarily a sewer pipe, and the fluid in the conduit may be any suitable fluid (i.e., a fluid which is relatively warm in winter and relatively cool in summer).
For example, in winter, the ground material to which the pipe portion is proximal is relatively warm, as is the fluid in the conduit. Also, the indoor fluid (e.g., air) typically is required to be warmed from time to time by conventional heating means, supplemented by the heat pump. In this situation, heat is transferred to the heat transfer medium in the pipe portion (i.e., circulated through the loop circuit, including the pipe portion): (a) from the fluid in the conduit; and (b) from the ground material. However, when the warmed heat transfer medium is circulated through the end portion, such heat transfer medium is brought into proximity to the heat transfer fluid, which is circulating through the heat exchanger in the heat pump (
When the indoor fluid is to be cooled (e.g., in summer), the situation is reversed. Heat is transferred from the (relatively warmer) heat transfer fluid in the heat exchanger to the (relatively cooler) heat transfer medium as it is circulated through the end portion of the ground loop circuit. In this situation, heat is transferred from the heat transfer medium: (a) to the ground material, which is cooler than the heat transfer medium; and (b) to the fluid in the conduit, which is also cooler than the heat transfer medium.
It will be appreciated by those skilled in the art that the heat exchange medium is circulated through the ground loop circuit by one or more pumps 40 (
Depending on the circumstances, it may be advantageous to include one or more supplemental loop circuits 50, to provide additional heating or cooling, as the case may be. Accordingly, in one embodiment, the heat exchange system 20 preferably also includes one or more supplemental loop circuits 50 in which a supplemental heat exchange medium 52 is circulatable, for heat exchange between the supplemental heat exchange medium and the heat exchange fluid in the heat exchanger. As can be seen in
The pipe body 28 preferably is made of any suitable material. In one embodiment, it is preferred that the pipe body 28 includes reinforced concrete. As can be seen in
The ground loop circuit 38 preferably includes tubing made of any suitable material(s), and suitable fastening means 63 as may be required to connect parts of the ground loop circuit together. As those skilled in the art would be aware of such suitable fastening means, further description thereof is unnecessary.
The end portion(s) 44 and the pipe portions 46 may be, for example, made of high-density polyethylene (HDPE) tubing. The inner diameter of tubing is determined by a number of factors. It has been found that HDPE tubing with an inner diameter of about 19.05 mm. (¾ inch) and an outer diameter of about 25.4 mm. (1 inch) is suitable, e.g., where the wall thickness is about 76.2 mm. (3 inches). (Those skilled in the art will appreciate that, in a larger pipe body with a thicker wall, larger tubing may be preferred.) The connecting portion 48 preferably is at least partially made of cross-linked polyethylene (“PEX”) tubing, or it may be HDPE tubing.
The heat exchange medium preferably is any suitable liquid or mixture of liquids, as would be known to those skilled in the art. For example, a mixture of water and antifreeze (e.g., propylene glycol, denatured alcohol, or methanol) has been found to be suitable. Any suitable mixture may be used. For instance, the antifreeze/water mixture may be between 30% and 50% (i.e., 30% by weight antifreeze to 50% by weight antifreeze). (As is known, the mixture with higher antifreeze content has less heat storage capacity.) The supplemental heat exchange medium also preferably is any suitable liquid(s), e.g., a mixture of water and antifreeze.
Similarly, the heat exchange fluid preferably is any suitable refrigerant (e.g., for use in a vapor-compression cycle), as is known in the art.
As noted above, the pipe body 28 preferably is made of reinforced concrete. As can be seen in
It is also preferred that the embedded part 58 of the pipe portion 46 is positioned substantially in a wall 66 of the pipe body 28. For example, as shown in
It appears that the density of the concrete of the pipe body affects the thermal conductivity thereof with a higher density tending to result in a correspondingly higher thermal conductivity.
As can be seen, for example, in
It will be appreciated by those skilled in the art that the materials used in the pipe body 28, and the positioning of the pipe portion 46 relative to the pipe body 28, preferably are selected according to various factors, including cost, structural strength, and thermal conductivity. For example, instead of reinforced concrete, the pipe body may be made of any suitable plastic material. However, and as noted above, a number of factors should be considered, e.g., cost; thermal conductivity; structural strength.
As can be seen in
In use, the heat exchange medium is pumped through an outflow part 72 of the connecting portion 48 to which pipe portions 46 are connected. In
As can be seen in
The pipe portion 46Z is connected in parallel with the pipe portions 46X, 46Y relative to the connecting portion 48. The heat transfer medium exists the pipe portion 46Z via the outlet part 76Z (as indicated by arrow “F”) to move the return part 78 of the connecting portion 48, so that the heat transfer medium from the pipe portion 46Z is then returned to the end portion 44, for heat transfer with the heat transfer fluid in the heat exchanger 24 (
As can be seen in
As an example, in
The purpose of connecting pipe portions in series, to form groups, is to improve the efficiency of heat transfer between the heat transfer medium in the embedded part and the ground material, and between such heat transfer medium and the fluid in the conduit. In the arrangement illustrated in
As described above, for the heat transfer medium flowing through the embedded part 58 in each pipe portion 46, the heat source (or heat sink, as the case may be) is both the ground material 36 and the fluid 32 flowing through the conduit 30. (For the purpose hereof, the ground material 36 and the fluid 32 are collectively referred to as the “Heat Source”, regardless of whether used as a heat source or a heat sink.) For example, referring to
It can be seen, therefore, that connection the pipe portions in series (e.g., the pipe portions 46A and 46B as shown in
However, those skilled in the art will appreciate that, at a certain point, the advantage gained by connecting the pipe portions in series disappears. This happen when the ΔT between the temperature of the heat transfer medium and the Heat Source disappears, i.e., when the AT approaches zero. At that point, the heat transfer medium should be returned to the connecting portion 48 via the outlet part (e.g., 76B, in
It will be understood that the pipe assemblies 49 are installed so that the conduits 30 defined therein are positioned at an appropriate grade relative to the horizontal. Such grade preferably is in accordance with the grade at which a prior art pipe is installed, as is well known in the art. It will be understood that the pipe assemblies 49 illustrated in
It can be seen, in
Accordingly, it is believed that the arrangement illustrated in
Preferably, the connecting portion 28 includes one or more manifolds 82 for receiving the heat exchange medium from each group 80 from pipe portions 46 respectively at substantially the same pressure, to permit the heat exchange medium to flow into the manifold from the groups at substantially equal rates of flow.
An alternative heat exchange system 120 of the invention is disclosed in
As can be seen in
Another embodiment of the heat exchange system 220 of the invention is disclosed in
As can be seen in
An alternative embodiment of the pipe assembly 349 of the invention is shown in
Another embodiment of the heat exchange system 420 of the invention is disclosed in
On occasion, the flow of the heat transfer medium through the outflow part 472 is impeded by frost which can build up inside the outflow part 472. Such frost build-up typically takes place in a region at or close to the ground surface, generally identified for illustrative purposes as 488 in
Another embodiment of the heat exchange system 520 is shown in
The invention also includes a method 601 which begins with a first step 603 of providing a mold for forming one or more pipe bodies (
It will be appreciated by those skilled in the art that the invention can take many forms, and that such forms are within the scope of the invention as described above. The foregoing descriptions are exemplary, and their scope should not be limited to the embodiments referred to therein.
Claims
1. A method of heat exchange with a heat transfer medium comprising:
- (a) providing a heat pump assembly for controlling an indoor fluid's temperature comprising a heat exchanger having a heat exchange fluid circulatable therein;
- (b) providing at least one end portion of a ground loop circuit through which the heat transfer medium is circulatable, said at least one end portion being positioned proximal to the heat exchanger for heat exchange between the heat transfer medium moving through said at least one end portion and the heat exchange fluid moving through the heat exchanger;
- (c) providing at least one pipe body comprising a substantially cylindrical main portion including a pipe wall defining at least one conduit therein in which at least one fluid is receivable, said at least one pipe body comprising an exterior surface adapted for engagement with ground material surrounding said at least one pipe body;
- (d) providing at least one pipe portion of the ground loop circuit through which the heat transfer medium is movable, said at least one pipe portion comprising an embedded part thereof positioned in the pipe wall of said at least one pipe body;
- (e) providing at least one connecting portion connecting said at least one pipe portion and said at least one end portion together to permit the heat transfer medium to circulate between said at least one end portion and said at least one pipe portion, said at least one connecting portion being engaged with ground material in which said at least one connecting portion is at least partially buried;
- (f) circulating the heat transfer medium through the ground loop circuit;
- (g) permitting heat transfer between the heat transfer medium in the embedded part and said at least one fluid in said at least one conduit; and
- (h) permitting heat transfer between the heat transfer medium in the embedded part and the ground material surrounding said at least one pipe body.
2. A method of heat exchange according to claim 1 additionally comprising:
- permitting heat transfer between the ground material engaged with said at least one connecting portion and the heat transfer medium moving through said at least one connecting portion.
3. A method according to claim 1 in which:
- the fluid flows through said at least one conduit in a predetermined first direction; and
- the heat transfer medium is moved through said at least one pipe portion generally in a second direction substantially opposite to the predetermined first direction for efficient heat exchange between the fluid and the heat transfer medium.
4. A method of heat exchange with a heat transfer medium comprising:
- (a) moving the heat transfer medium through at least one pipe portion of a ground loop circuit, said at least one pipe portion comprising an embedded part thereof positioned in a pipe wall of at least one pipe body defining at least one conduit therein through which at least one fluid is flowable, said at least one pipe body comprising an exterior surface engaged with ground material surrounding said at least one pipe body;
- (b) permitting substantially simultaneous heat exchange through the pipe wall between: (i) the heat transfer medium and said at least one fluid in said at least one conduit as the heat transfer medium moves through the embedded part of said at least one pipe portion, and (ii) the heat transfer medium and the pipe ground material as the heat transfer medium moves through the embedded part of said at least one pipe portion;
- (c) moving the heat transfer medium through an end portion of the ground loop circuit positioned proximal to a heat exchanger with a heat exchange fluid circulated therein;
- (d) permitting heat exchange between the heat transfer medium and the heat exchange fluid as the heat transfer medium flows through the end portion; and
- (e) moving the heat transfer medium through at least one connecting portion of the ground loop circuit in fluid communication with said at least one pipe portion and with the end portion to allow the heat transfer medium to circulate through the ground loop circuit.
5. A method according to claim 4 additionally comprising:
- (f) permitting heat exchange between the heat transfer fluid and the ground material that is engaged with said at least one connecting portion as the heat transfer medium moves through said at least one connecting portion.
6. A method of heat exchange according to claim 5 in which:
- the fluid is flowable through a plurality of pipe bodies in a first predetermined direction, the pipe bodies comprising pipe walls in which the embedded parts of a plurality of pipe portions are positioned; and
- the heat transfer medium is moved through the pipe portions in a second direction that is generally opposed to the first predetermined direction of flow of the fluid through the conduits of the pipe bodies.
7. A method according to claim 5 in which:
- a plurality of pipe bodies is provided, the pipe bodies being connected end-to-end to substantially align the conduits defined thereby, for permitting the fluid therein to flow therethrough in a first predetermined direction;
- a plurality of pipe portions is provided, the pipe portions comprising embedded parts thereof positioned in the walls of the pipe bodies respectively, the pipe portions being arranged into respective groups;
- a plurality of connecting portions is provided for connecting the groups of pipe portions respectively to the end portion; and
- each said group being connected to the connecting portion therefor in parallel relative to the groups of pipe portions located adjacent thereto.
8. A method of heat exchange according to claim 7 in which:
- a manifold is provided for receiving the heat transfer medium from each group respectively moving from the pipe portions and toward the end portion at substantially the same pressure, to permit the heat transfer medium to flow into the manifold from the groups at substantially equal rates of flow.
9. A method of heat exchange according to claim 5 additionally comprising:
- (g) providing a supplemental loop circuit through which the heat transfer medium is circulatable; and
- (h) providing a three-way valve controlled by a controller thereof, the three-way valve being switchable between a first condition, in which the supplemental loop circuit is connected to the end portion, and a second condition, in which the supplemental loop circuit is connected to said at least one connecting portion, to permit the heat transfer medium to move through the ground loop circuit.
10. A method of heat exchange according to claim 9 additionally comprising:
- (i) providing a temperature sensor positioned for sensing at least one temperature of the heat transfer medium exiting the end portion and flowing into the connecting portion toward said at least one pipe portion;
- (j) if said at least one temperature of the heat transfer medium exiting the end portion and flowing into said at least one connecting portion is below a predetermined temperature, generating an activation signal;
- (k) transmitting said activation signal to the controller;
- (l) providing a variable speed pump, for pumping the heat transfer medium from the supplemental loop circuit to said at least one connecting portion toward said at least one pipe portion; and
- (m) upon the activation signal being received at the controller, via the controller, the three-way valve is switched into the second condition: to permit the heat transfer medium from moving from the ground loop portion directly to the end portion; and the variable speed pump is energized, to move the heat transfer medium from the supplementary loop circuit to said at least one connecting portion toward said at least one pipe portion.
11. A method according to claim 5 additionally comprising:
- (g) providing a supplemental loop circuit in fluid communication with the connecting portion, to permit the heat transfer medium to circulate: from the end portion to the supplemental loop circuit; from the supplemental loop circuit to said at least one connecting portion; from said at least one connecting portion to said at least one pipe portion; and from said at least one pipe portion, via said at least one connecting portion, to the end portion.
12. A method according to claim 4 in which said at least one pipe body comprises at least one internal wall portion positioned between the embedded part and said at least one conduit, and said at least one internal wall portion is formed for thermal conductivity therethrough.
13. A method according to claim 12 in which said at least one pipe body comprises at least one external wall portion comprising the exterior surface and positioned between the embedded part and the ground material, and said at least one external wall portion is formed for thermal conductivity therethrough.
14. A method according to claim 4 additionally comprising:
- providing at least one supplemental loop circuit in which a supplemental heat exchange medium is circulatable, said at least one supplemental loop circuit being at least partially engaged with said ground material for heat exchange between said ground material and said supplemental heat exchange medium, and for subsequent heat exchange between said supplemental heat exchange medium and the heat exchange fluid in the heat exchanger.
15. A method according to claim 4 in which the embedded part is located substantially equidistant between the exterior surface of said at least one pipe body and said at least one conduit.
16. A method for heat exchange with a heat transfer medium comprising:
- (a) providing a ground loop circuit through which the heat transfer medium is circulatable, the ground loop circuit comprising: an end portion, positioned proximal to a heat exchanger through which a heat exchange fluid is circulatable; at least one pipe portion comprising an embedded part positioned in a pipe wall of at least one pipe body, said at least one pipe body defining at least one conduit therein through which a fluid is flowable, said at least one pipe body having an exterior surface engaged with ground material; at least one connecting portion connecting the end portion and said at least one pipe portion, said at least one connecting portion engaging the ground material;
- (b) circulating the heat transfer medium through the ground loop circuit, to permit: heat transfer between the heat transfer medium moving through the end portion and the heat exchange fluid; heat transfer between the heat transfer medium moving through the embedded part and the fluid in said at least one conduit; heat transfer between the heat transfer medium moving through the embedded part and the ground material engaged with said at least one pipe body; and heat transfer between the heat transfer medium moving through said at least one connecting portion to the end portion and the ground material engaged with said at least one connecting portion.
17. A method according to claim 16 additionally comprising:
- (c) providing a supplemental loop circuit through which a supplemental heat exchange medium is circulatable therethrough and to the end portion, the supplemental loop circuit including a loop circuit for heat transfer between the supplemental heat exchange medium and the ground material engaged with the supplemental loop circuit; and
- (d) permitting heat exchange between the heat exchange fluid and the supplemental heat exchange medium as the supplemental heat exchange medium moves through the end portion.
18. A method according to claim 16 additionally comprising:
- (c) providing a supplemental loop circuit connectable with the ground loop circuit via a three-way valve controlled by a controller, the three-way valve being switchable between a first condition, in which the heat transfer medium is movable from the supplemental loop circuit directly to the end portion, and a second condition, in which the heat transfer medium is movable from the supplemental loop circuit to said at least one connecting portion toward said at least one pipe portion;
- (d) providing a temperature sensor for sensing at least one temperature of the heat transfer medium moving through said at least one connecting portion toward said at least one pipe portion;
- (e) providing a variable speed pump for moving the heat transfer medium out of the supplementary loop circuit;
- (f) upon the temperature sensor determining that said at least one temperature is less than a predetermined temperature, the temperature sensor generates a first signal to switch the three-way valve to the second condition;
- (g) upon the variable speed pump receiving the first signal, the variable speed pump is energized, and pumps the heat transfer medium from the supplementary loop circuit to said at least one connecting portion toward said at least one pipe portion; and
- (h) upon the temperature sensor determining that said at least one temperature is greater than the predetermined temperature, the temperature sensor generates a second signal to switch the three-way valve to the first condition.
19. A method according to claim 16 additionally comprising:
- (c) providing a supplemental loop circuit connected with the ground loop circuit; and
- (d) permitting the heat transfer medium to circulate from the supplemental loop circuit to said at least one connecting portion toward said at least one pipe portion and to the end portion.
Type: Application
Filed: Dec 10, 2014
Publication Date: Apr 2, 2015
Applicant: RENEWABLE RESOURCE RECOVERY CORP. (Sudbury)
Inventors: Boris P. Naneff (Sudbury), Robert Mancini (Bolton), Leslie J. Lisk (Coniston), John D. Hood (Sudbury)
Application Number: 14/565,621
International Classification: F24J 3/08 (20060101); F28F 27/02 (20060101);