US20110073275A1 - Geothermal system and tubing therefor - Google Patents
Geothermal system and tubing therefor Download PDFInfo
- Publication number
- US20110073275A1 US20110073275A1 US12/804,291 US80429110A US2011073275A1 US 20110073275 A1 US20110073275 A1 US 20110073275A1 US 80429110 A US80429110 A US 80429110A US 2011073275 A1 US2011073275 A1 US 2011073275A1
- Authority
- US
- United States
- Prior art keywords
- fluid
- tubing
- ground
- section
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24T—GEOTHERMAL COLLECTORS; GEOTHERMAL SYSTEMS
- F24T10/00—Geothermal collectors
- F24T10/10—Geothermal collectors with circulation of working fluids through underground channels, the working fluids not coming into direct contact with the ground
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/10—Geothermal energy
Definitions
- This invention is directed to a geothermal system, and more particularly to the fluid transfer structure therefor.
- Geothermal energy systems are known in the art.
- a geothermal heat pump utilizes the ground temperature to heat or cool a fluid through energy transfer with the ground to regulate the interior temperature of a facility.
- the system uses the earth as either a source of heat in the winter or as a coolant in the summer.
- the geothermal heat pumps take advantage of substantially consistent moderate temperatures in the shallow ground to boost efficiency and reduce operational cost.
- the temperature of the ground remains fairly constant except for very close to the surface while the temperature of the air above ground, and within a facility, changes relatively dramatically.
- the ground temperature below the surface is normally cooler than the ambient temperature above ground.
- the temperature below the ground particularly in northern climates, is warmer than the ambient temperature above ground.
- the system must take advantage of the temperature differential across all seasons.
- the geothermal heat pumps include a pump which pumps fluid through tubing.
- the tubing extends through the ground and exchanges energy with the ground to enable the fluid to either lose or gain heat dependent upon whether the temperature of the fluid is greater than or less than the temperature of the ground through which it passes.
- the fluid conveying system then carries the fluid back to the home or facility above the ground to control the environment therewithin. It is known in the art to use plastic tubing to convey the fluid through the ground.
- a system having a pump.
- the pump is operatively coupled to a tubing having made of a high thermally conductive material.
- the tubing is adapted to promote the transfer of energy between a fluid contained therein and earth surrounding the pipe.
- the tubing is made from a high density polyethylene. In another embodiment the tubing has a thermal conductivity of about 0.4 W/(m ⁇ K). In another embodiment, the pipe includes a first section made of a high density polyethylene and a second section. The first section has a thermal conductivity one and a half to five times as great as the thermal conductivity of the second section.
- FIG. 1 is a schematic drawing of a heat pump constructed in accordance with the invention.
- FIG. 2 is a schematic diagram of the fluid conveying section of the heat pump constructed in accordance with a second embodiment of the invention.
- Heat pump 10 includes a pump 12 for pumping a fluid.
- a pipe, generally indicated as 14 conveys the fluid from pump 12 in the direction of Arrow A. At least a portion of the path of pipe 14 is through ground 100 near the facility (a house, building or the like) 102 to be controlled by heat pump 10 .
- pipe 14 is a plastic tubing.
- pipe tubing 14 is formed of a high density polyethylene (above 0.940 g/cm 3 ) having a high thermal conductivity, preferably about 0.5 W/(m ⁇ K) or higher, and preferably, about 0.7 W/(m ⁇ K) or higher.
- the temperature of the earth reaches about 8° C.
- the desired temperature of the fluid approximates that of the temperature of the ground at the depth to which the tubing 14 travels.
- the temperature of the ground changes, from the ambient temperature, as seen in FIG. 2 , at the surface of the ground to the desired temperature beneath the surface. Therefore, to maximize the heat transfer efficiency in accordance with the invention, the fluid is exposed to a temperature of the ground as long as necessary until the temperature of the fluid approaches a desired temperature differential.
- tube 14 includes a first section 18 and a second section 20 .
- First section 18 has a significantly higher thermal conductivity than second section 20 significantly greater than 0.45 W/(m ⁇ K).
- Second section 20 is downstream of the fluid and sufficiently downstream of the return point of the path of tubing 14 (that point in which tubing 14 begins its final path towards surface 104 ) of ground 100 .
- second section 20 having the lower thermal conductivity less than 0.3 W/(m ⁇ K), in order to prevent such temperature exchange within a fluid, should begin at a point between the return of tubing 14 to the surface and a position where the temperature gradient will result in a changing temperature of the fluid within tubing 14 . In this way, the exposure of the fluid to the desired ground temperature is maximized and the possibility of energy transfer to lose the desired temperature is minimized.
- the thermal conductivity of first section 18 is substantially higher than that of second section 20 .
- the thermal conductivity of first section 18 is one and a half to three times greater than the thermal conductivity of second section 20 .
- the thermal conductivity of second section 20 is about 0.3 W/(m ⁇ K) or less.
- Second section 20 which thermally isolates the fluid contained therein may be made of a low density polyethylene or a polypropylene; significantly less than 0.940 g/cm 3 .
- a fluid is pumped through tubing 14 in the direction of arrow A.
- the temperature of the fluid approaches, through thermal exchange with the ground, that of the ground.
- point F in this embodiment the fluid passes through second section 20 before the temperature of the fluid has substantially changed.
Abstract
Description
- This application claims priority to U.S. Provisional Application No. 61/226,561 filed on Jul. 17, 2009 in its entirety.
- This invention is directed to a geothermal system, and more particularly to the fluid transfer structure therefor.
- Geothermal energy systems are known in the art. By way of example a geothermal heat pump utilizes the ground temperature to heat or cool a fluid through energy transfer with the ground to regulate the interior temperature of a facility. The system uses the earth as either a source of heat in the winter or as a coolant in the summer. The geothermal heat pumps take advantage of substantially consistent moderate temperatures in the shallow ground to boost efficiency and reduce operational cost. The temperature of the ground remains fairly constant except for very close to the surface while the temperature of the air above ground, and within a facility, changes relatively dramatically.
- During the summer, the ground temperature below the surface is normally cooler than the ambient temperature above ground. In the winter, for those countries above the equator, the opposite is true and the temperature below the ground, particularly in northern climates, is warmer than the ambient temperature above ground. To maximize the operation of the geothermal system, the system must take advantage of the temperature differential across all seasons.
- The geothermal heat pumps include a pump which pumps fluid through tubing. The tubing extends through the ground and exchanges energy with the ground to enable the fluid to either lose or gain heat dependent upon whether the temperature of the fluid is greater than or less than the temperature of the ground through which it passes. The fluid conveying system then carries the fluid back to the home or facility above the ground to control the environment therewithin. It is known in the art to use plastic tubing to convey the fluid through the ground.
- These systems, although rudimentary have been satisfactory, but fairly inefficient. First, the materials used have a low thermal conductivity, so that the necessary heat exchange between the ground and the fluid is difficult, requiring a longer run of tubing within the ground to maximize energy transfer.
- Furthermore, energy is wasted because the thermal conductivity is not sufficiently high to maintain the temperature of the fluid for long stretches of travel through the ground. Therefore, the transfer of energy between the ground and the fluid continues, so that on the return trip to the facility the fluid is either heating or cooling the ground. Accordingly, a system which overcomes the shortcomings of the prior art is desired.
- A system is provided having a pump. The pump is operatively coupled to a tubing having made of a high thermally conductive material. The tubing is adapted to promote the transfer of energy between a fluid contained therein and earth surrounding the pipe.
- In one embodiment, the tubing is made from a high density polyethylene. In another embodiment the tubing has a thermal conductivity of about 0.4 W/(m−K). In another embodiment, the pipe includes a first section made of a high density polyethylene and a second section. The first section has a thermal conductivity one and a half to five times as great as the thermal conductivity of the second section.
- For a fuller understanding of the invention, reference is had to the following description, taken in connection with the following drawings in which:
-
FIG. 1 is a schematic drawing of a heat pump constructed in accordance with the invention; and -
FIG. 2 is a schematic diagram of the fluid conveying section of the heat pump constructed in accordance with a second embodiment of the invention. - Reference is made to the
FIGS. 1 and 2 in which a geothermal heat pump, generally indicated as 10, is provided.Heat pump 10 includes apump 12 for pumping a fluid. A pipe, generally indicated as 14 conveys the fluid frompump 12 in the direction of Arrow A. At least a portion of the path ofpipe 14 is throughground 100 near the facility (a house, building or the like) 102 to be controlled byheat pump 10. In a preferred embodiment,pipe 14 is a plastic tubing. - In one embodiment of the invention,
pipe tubing 14 is formed of a high density polyethylene (above 0.940 g/cm3) having a high thermal conductivity, preferably about 0.5 W/(m−K) or higher, and preferably, about 0.7 W/(m−K) or higher. - At the depths through
ground 20 through whichtubing 14 will travel, the temperature of the earth reaches about 8° C. The desired temperature of the fluid approximates that of the temperature of the ground at the depth to which thetubing 14 travels. - The temperature of the ground changes, from the ambient temperature, as seen in
FIG. 2 , at the surface of the ground to the desired temperature beneath the surface. Therefore, to maximize the heat transfer efficiency in accordance with the invention, the fluid is exposed to a temperature of the ground as long as necessary until the temperature of the fluid approaches a desired temperature differential. - However, as is known in the prior art systems, the fluid traveling through
tubing 14 continues to exchange energy with the ground on its return trip as it traverses the ground temperature gradient on the return to the environment to be controlled. Accordingly, in a preferred embodiment,tube 14 includes afirst section 18 and asecond section 20.First section 18 has a significantly higher thermal conductivity thansecond section 20 significantly greater than 0.45 W/(m−K).Second section 20 is downstream of the fluid and sufficiently downstream of the return point of the path of tubing 14 (that point in whichtubing 14 begins its final path towards surface 104) ofground 100. - As
tubing 14 returns to the surface, the temperature gradient of the ground approaches that of the surface temperature. As a result, the fluid will exchange energy with the ground to either lose or gain temperature as it experiences this new temperature gradient. Accordingly,second section 20, having the lower thermal conductivity less than 0.3 W/(m−K), in order to prevent such temperature exchange within a fluid, should begin at a point between the return oftubing 14 to the surface and a position where the temperature gradient will result in a changing temperature of the fluid withintubing 14. In this way, the exposure of the fluid to the desired ground temperature is maximized and the possibility of energy transfer to lose the desired temperature is minimized. - In a preferred embodiment, the thermal conductivity of
first section 18 is substantially higher than that ofsecond section 20. In a preferred embodiment, the thermal conductivity offirst section 18 is one and a half to three times greater than the thermal conductivity ofsecond section 20. In a still further preferred embodiment, the thermal conductivity ofsecond section 20 is about 0.3 W/(m−K) or less.Second section 20 which thermally isolates the fluid contained therein may be made of a low density polyethylene or a polypropylene; significantly less than 0.940 g/cm3. - During use, a fluid is pumped through
tubing 14 in the direction of arrow A. As fluid traverses throughsection 18, the temperature of the fluid approaches, through thermal exchange with the ground, that of the ground. At the return, point F in this embodiment, the fluid passes throughsecond section 20 before the temperature of the fluid has substantially changed. - It is to be understood that although used by the invention, that the ground and the fluid make up no part of this invention.
- It will thus be seen that the objects set forth above, and those made apparent from the precedent description, are efficiently obtained and, since certain changes may be made in the above construction without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense.
- It is also to be understood that the following claims are intended to cover all generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language might be set to fall therebetween.
Claims (4)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/804,291 US20110073275A1 (en) | 2009-07-17 | 2010-07-19 | Geothermal system and tubing therefor |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US22656109P | 2009-07-17 | 2009-07-17 | |
US12/804,291 US20110073275A1 (en) | 2009-07-17 | 2010-07-19 | Geothermal system and tubing therefor |
Publications (1)
Publication Number | Publication Date |
---|---|
US20110073275A1 true US20110073275A1 (en) | 2011-03-31 |
Family
ID=43495943
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/804,291 Abandoned US20110073275A1 (en) | 2009-07-17 | 2010-07-19 | Geothermal system and tubing therefor |
Country Status (2)
Country | Link |
---|---|
US (1) | US20110073275A1 (en) |
CA (1) | CA2710219A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2013074853A1 (en) * | 2011-11-15 | 2013-05-23 | Earth To Air Systems, Llc | Dx geothermal heat pump and refrigeration systems |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4741388A (en) * | 1984-12-20 | 1988-05-03 | Kazuo Kuroiwa | Underground heat exchanging apparatus |
US4993483A (en) * | 1990-01-22 | 1991-02-19 | Charles Harris | Geothermal heat transfer system |
US5561985A (en) * | 1995-05-02 | 1996-10-08 | Ecr Technologies, Inc. | Heat pump apparatus including earth tap heat exchanger |
US7080524B2 (en) * | 2002-12-31 | 2006-07-25 | B. Ryland Wiggs | Alternate sub-surface and optionally accessible direct expansion refrigerant flow regulating device |
US7578140B1 (en) * | 2003-03-20 | 2009-08-25 | Earth To Air Systems, Llc | Deep well/long trench direct expansion heating/cooling system |
US20110011558A1 (en) * | 2009-07-15 | 2011-01-20 | Don Dorrian | Thermal conductivity pipe for geothermal applications |
US8109110B2 (en) * | 2007-10-11 | 2012-02-07 | Earth To Air Systems, Llc | Advanced DX system design improvements |
-
2010
- 2010-07-19 CA CA2710219A patent/CA2710219A1/en not_active Abandoned
- 2010-07-19 US US12/804,291 patent/US20110073275A1/en not_active Abandoned
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4741388A (en) * | 1984-12-20 | 1988-05-03 | Kazuo Kuroiwa | Underground heat exchanging apparatus |
US4993483A (en) * | 1990-01-22 | 1991-02-19 | Charles Harris | Geothermal heat transfer system |
US5561985A (en) * | 1995-05-02 | 1996-10-08 | Ecr Technologies, Inc. | Heat pump apparatus including earth tap heat exchanger |
US7080524B2 (en) * | 2002-12-31 | 2006-07-25 | B. Ryland Wiggs | Alternate sub-surface and optionally accessible direct expansion refrigerant flow regulating device |
US7578140B1 (en) * | 2003-03-20 | 2009-08-25 | Earth To Air Systems, Llc | Deep well/long trench direct expansion heating/cooling system |
US8109110B2 (en) * | 2007-10-11 | 2012-02-07 | Earth To Air Systems, Llc | Advanced DX system design improvements |
US20110011558A1 (en) * | 2009-07-15 | 2011-01-20 | Don Dorrian | Thermal conductivity pipe for geothermal applications |
Also Published As
Publication number | Publication date |
---|---|
CA2710219A1 (en) | 2011-01-17 |
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Legal Events
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AS | Assignment |
Owner name: NATIONAL BANK OF CANADA, CANADA Free format text: SECURITY AGREEMENT;ASSIGNORS:IPL, INC.;PLASTIC ENTERPRISES, CO., INC.;REEL/FRAME:027873/0070 Effective date: 20120302 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |
|
AS | Assignment |
Owner name: PLASTIC ENTERPRISES, CO., INC., CANADA Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:NATIONAL BANK OF CANADA;REEL/FRAME:054090/0777 Effective date: 20201015 Owner name: IPL, INC., CANADA Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:NATIONAL BANK OF CANADA;REEL/FRAME:054090/0777 Effective date: 20201015 |