GB2521623A - Coaxial borehole heat exchangers and installation thereof - Google Patents
Coaxial borehole heat exchangers and installation thereof Download PDFInfo
- Publication number
- GB2521623A GB2521623A GB1322910.9A GB201322910A GB2521623A GB 2521623 A GB2521623 A GB 2521623A GB 201322910 A GB201322910 A GB 201322910A GB 2521623 A GB2521623 A GB 2521623A
- Authority
- GB
- United Kingdom
- Prior art keywords
- borehole
- outer tubular
- tubular casing
- heat exchanger
- grout
- 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.)
- Withdrawn
Links
- 238000009434 installation Methods 0.000 title abstract description 8
- 239000011440 grout Substances 0.000 abstract description 29
- 238000005260 corrosion Methods 0.000 abstract description 15
- 230000007797 corrosion Effects 0.000 abstract description 15
- 238000000034 method Methods 0.000 abstract description 14
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 abstract description 10
- 230000008569 process Effects 0.000 abstract description 9
- 239000002184 metal Substances 0.000 abstract description 7
- 229910052751 metal Inorganic materials 0.000 abstract description 7
- 239000011787 zinc oxide Substances 0.000 abstract description 5
- 239000012530 fluid Substances 0.000 description 12
- 239000003112 inhibitor Substances 0.000 description 10
- 229910000831 Steel Inorganic materials 0.000 description 9
- 239000010959 steel Substances 0.000 description 9
- 238000012546 transfer Methods 0.000 description 8
- 238000005553 drilling Methods 0.000 description 7
- 238000003466 welding Methods 0.000 description 7
- 239000000203 mixture Substances 0.000 description 5
- 238000009472 formulation Methods 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000004513 sizing Methods 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical group 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/13—Methods or devices for cementing, for plugging holes, crevices or the like
- E21B33/14—Methods or devices for cementing, for plugging holes, crevices or the like for cementing casings into boreholes
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B36/00—Heating, cooling or insulating arrangements for boreholes or wells, e.g. for use in permafrost zones
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24T—GEOTHERMAL COLLECTORS; GEOTHERMAL SYSTEMS
- F24T10/00—Geothermal collectors
-
- 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
- F24T10/13—Geothermal collectors with circulation of working fluids through underground channels, the working fluids not coming into direct contact with the ground using tube assemblies suitable for insertion into boreholes in the ground, e.g. geothermal probes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24T—GEOTHERMAL COLLECTORS; GEOTHERMAL SYSTEMS
- F24T10/00—Geothermal collectors
- F24T2010/50—Component parts, details or accessories
- F24T2010/53—Methods for installation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F2275/00—Fastening; Joining
- F28F2275/06—Fastening; Joining by welding
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Fluid Mechanics (AREA)
- Environmental & Geological Engineering (AREA)
- Physics & Mathematics (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
- Earth Drilling (AREA)
Abstract
A coaxial borehole heat exchanger 58 comprising an outer tubular metal casing 54 located in a borehole 66, the outer tubular metal casing comprising a series of tubular sections 50, 52 which have opposed ends interconnected by an annular weld 56. The method of installation involves the lower section 50 being placed into the borehole 66 and the upper section 52 being welded to the upper end of the lower section, this process is repeated with multiple sections to reach the required casing length. The casing is surrounded in the borehole by a grout layer (10, fig 5), the grout is corrosion resistant preferably by the inclusion of zinc oxide in the grout.
Description
Coaxial Borehok heat Exchangers and lnstaliathm Thereof The present invention relates to a coaxial borehole heat exchanger and to a method of installing a coaxial borebde heat exchanger. in particular the present invention relates to the surface welding together of steel tubes to connect together muitipk tubes utilized to form an outer casing in coaxi& borehole heat exchangers in order to improve the thermal transfer properties of the heat exchanger.
As part of the constrdction process of a coaxial borehole heat exchanger (BHF.) of a geothermal energy system, in accordance with known practice in borehole technology, multiple steel tubes are connected together and installed in the borehole to act as the outer tubular casing of the coaxial design.
As shown in Figure 1, the resultant steel outer tubular casing 2 provides a thermally conductive interthce 4 between the circulated fluid, within the central bore 6 of the outer tubular casing 2, and the surrounding earth 8, to enable thermal energy heat exchange therebetween, The outer tubular casing 2 is grouted in place with thennally enhanced grout co provide thermal continuity between the outer tubular casing 2 and the borehole wall 12.
In addition, the grout 10 provides a protective bather for the outer tubular casing 2 to protect the outer tubular casing 2 from corrosion. The thermally enhanced grout 10 is the area of potentially the lowest thermal conductivity. Consequently, it would be desirable to minimise the grout thickness in order to improve the thermal energy transfer between the outer tubular casing 2 and the borehole wall 12.
The outer tubular casing dimensions are determined in order to balance the needs to provide (I) an outer tubular casing surface area to achieve high thermal energy transfer; (2) an internal Fluid capacity to achieve the desired flow rates of the working fluid in the geothermal system; and (3) a mechanical strength to achieve structural integrity of the outer tubular casing during the process of inserting the coaxial borehole heat exchanger into a borehole.
1-lowever, as part of the insertion process in which the borehole heat exchanger in inserted into a predrilled borehole which may be hundreds of metres in depth and may significantly vary in inclination along its length. individual lengths of the outer tubular casing are successively joined together inmtediateiy prior to be inserted into the ground. in current geothermal borehole practice, a threaded connection is provided to interconnect successive lengths of the outer tubular casing.
As shown in Figure 2, a known threaded connection is of a flush type in which one tube end 14 has a male thread 16 and the other tube end 18 has a female thread 20. Th.e male and female ends 14, 18 are threaded together to form a flush type connection therebetween in which the outer diameter of the connection is the same as that of the outer tubular casings 2.
Such a flush type connection requires the steel outer tubular casing 2 to be of a minimum thickness to enable threadng, especially on the female connection to retain mechanical strength. However, such a thickness is not necessarily the optimum wall thickness for thermal energy transfer or for achieving points (1) to (3) identified above.
Alternatively, as shown in Figure 3, another known outer casing threaded connection provides a female threaded collar 22 which connects together two opposed male threaded ends 24, TIc collar has an outer diameter which is greater than that of the outer tubes 2, and so the connection is not flush with the outer tubular casings 2. If such a nonJiush type or collar type threaded connection s utilized, then although a thinner wall thickness can be used for the male connection on the outer tubular casing, the structure and dimensions of the external collar 22 required to maintain mechanical strength of the female connection in turn requires a thick external collar 22 which necessitates an effective increase in the outer diameter of the steel outer casing 2 at each connection. This in turn requires a larger borehole diameter to have been drilled in order to safely install the borehole heat exchange. The use of a diametrically larger collar also results in an increased thickness of the grout between the borehole and the outer tubular casing. Increased grout thickness may reduce the thermal energy transfer between the outer tubular casing and the borehole wail.
There is consequently a need in the art for a borehole heat exchanger which can at least partially obviate these problems with the outer casings of known borehole heat exchangers.
In particular, there is a need in the art for a borehole heat exchanger incorporating an outer tubular casing which can provide (1) an outer casing surface area to achieve high thermal energy transfer; (2) an internal fluid capacity to achieve the desired flow rates of the working fluid in the geothermal system; and (3) a mechanical strength to achieve structural integrity of the outer casing during the process of inserting the coaxial borehole heat exchanger into a borehole.
The present invention aims al least partially to meet these needs iii the art, Accordingly, the present invention provides a coaxial borehole heat exchanger comprising an outer tubuar casing located in a borehole, the outer tUbular metal casing comprising a series of tubular sections, wherein opposed ends of adjacent tubular sections are interconnected by a respective annular weld.
The present invention further provides a method of installing a coaxial borehole heat exchanger in a borehole, the method comprising the steps oh a. providing a plurality of tubular metal sections; b. successively disposing the tubular metal sections in the borehole; and c. welding a respective annular weld between opposed ends of adjacent tubular sections to serially interconnect the plurality of tubular metal sections to form an outer tubular casing of coaxial borehole heat exchanger located in the borehole.
The present invention thrther provides a coaxial borehole heat exchanger comprising an outer tubular casing located in a borehole having a diameter of from 160 to 180mm, the outer tubular metal casing comprising a series of tubular sections, wherein the tubular sections have a wall thickness of from 4 to 6mm, typically about 5mm, the tubular sections have an external diameter of from 120 to I 30mm, and an annular grout layer is located between the outer tubular casing and a wall of the borehole, wherein the annular grout layer comprises a grout tbrmulation which incorporates a corrosion inhibitor.
Preferred features are defined in the dependent claims.
The present invention is predicated on the finding by the present inventors that outer tubular casings of a borehole heat exchanger carE be interconnected by welded connections resulting in the elimination of threaded connections. The use of welded connections obviates the dimensional and structural restrictions of threaded connections. as discussed above, which consequently can enable optimum sizing of all key dimensions of the outer tubular casings.
Such optimum sizing can in turn not only enable optimum thermal energy transfer within the borehole heat exchanger but also maintain mechanical integrity of the outer tubular casing.
Furthermore, the costs of installation of the geothennal energy system can be signiflcantiy reduced A smaller drilling bit size can be employed to drill a borehole for accommodating a borehole heat exchanger according to the present invention of similar thermal capacity to the known threaded borehole heat exchanger. Drilling bits sizes are standardised in the oil and gas industry. For instance, a common drill bit size has a diameter of 7 7/8 inches (200 mm) with the next smaller drill bit size having a diameter of 6 3/4 inches (17L5 mm). The present invention can achieve a similar thermal capacity of the installed borehole heat exchanger using a drill hit size one size smaller, which results in significant cost savings, both in capital costs and. installation costs.
Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 illustrates a cross-section through a known borehole heat exchanger of a geothermal energy system installed in a borehole in the ground; Figure 2 illustrates an exploded side view of two sections of an outer t-uhular casing, prior to being interconnected together, of a first known borehole heat exchanger; Figure 3 illustrates a side view of two sections of an outer tubular casing, interconnected together by a threaded collar, of a second known borehole heat exchanger; Figure 4 illustrates a side view of two sections of an outer tubular casing, interconnected together by a weld, of a borehole heat exchanger in accordance with an embodiment of the present invention; and Figure 5 illustrates a cross-section through the borehole heat exchanger of Figure 4 when installed in a borehole in the ground as a component of a geothermal energy system, Referring to Figures 4 and 5, there is shown two sections 50, 52 of an outer tubular casing 54, interconnected together by an annular weld 56, of a coaxial borehole heat exchanger 58 in accordance with an embodiment of the present invention, The borehole heat exchanger (BITE) 58 is incorporated into a geothermal energy system and includes very many such outer tubular casing sections interconnected by successive welds to form an elongate outer tubular casing, typically hundreds of metres in length.
The outer tubular casing 54 is typically composed of steel, and the steel composition is selected so as to he readily weldable on-site during the construction process for the borehole heat exchanger 58. A conventional welding process is employed to form the annular weld 56, for example orbital welding.
The outer tubular casing 54 provides a thermally conductive interface 60 between the circulated fluid, within the central bore 62 of the outer tubular casing 54 and typically comprising ethylene glycol incorporating a corrosion inhibitor, and the surrounding earth 8, to enable thermal energy heat exchange therehetween, The outer tubular casing 54 is grouted in place with thermally enhanced grout 10 to provide thermal continuity between the outer tubular casing 54 and the borehole wall 12. In addition, the grout 10 provides a protective barrier for the outer tubular casing 54 to protect the outer tubular casing 54 from corrosion, for example by containing zinc oxide.
During the construction process, the lower section 50 is inserted into the upper end of the borehole 66. Then the lower end 68 of the subsequent upper section 52 is welded to the upper end 70 of the lower section 50 forming the annular weld 56. This welding cycle is repeated to interconnect plural sections together to form an elongate outer tubular casing 54 of the desired length which extends the entire length of the predrilled borehole 66.
The inventors have found that by welding the outer tubular casing sections 50, 52 together, thereby eliminating the need for threaded connections of the known interconnection systems as illustrated in Figures 2 and 3., this allows a thinner walled outer tubular casing 54 to he used. This in turn can provide an optimum design for the structure and dimensions of the outer tubular casing, which can overcome the ahovedescrihed problems of the known outer tubular casings and in particular can pravide, in combination, (1) an outer tubular casing sw-face area to achieve high thermal energy transfer; (2) an internal fluid capacity to achieve the desired flow rates of the working fluid in the geothermal system; and (3) a mechanical strength to achieve structural integrity of the outer tubular casing during the process of inserting the coaxial borehole heat exchanger into a borehole.
Typically, the tubular sections 50, 52 have a wall thickness of from 3 to Stunt preferably from 4 to 6mm, typically about 5mm, These thicknesses provide that the wall of the borehole heat exchanger can survive being subjected to an internal hydraulic pressure of up to about 20 bar at a typical depth of 200 metres. Typically, the tubular sections 50, 52 have an external diameter of from 120 to 130mm. preferably from 125 to 128mm, Typically, the tubular sections 50, 52 have an internal diameter of from 115 to 120mm. Typically, the coaxial borehole heat exchanger 58 is located in a borehole 66 having a diameter of from 1 60 to 180mm, preferably from 145 to i 75mm. Typically, the annular grout layer 10 located between the outer tubular casing 54 and the wail of the borehole 66 has a thickness of from to 27mm, preferably from 20 to 25mm.
The annular grout layer 10 comprises a grout formulation which incorporates a corrosion inhibitor, and the corrosion inhibitor typically comprises or includes zinc oxide at a corrosion inhibitor or zinc oxide concentration of from 0,1 to 0.8 wt%, typically from 0.3 to 0.5 wt%, based on the weight of the grout formulation. The corrosion inhibitor, particularly when the corrosion inhibitor is a metal oxide such as zinc oxide, may also increase the thermal conductivity of the grout. The maximum concentration of the corrosion inhibitor within the grout formulation is determined so as not negatively to affect the ability of the grout to set in situ within the borehole, and the maximum amount of the corrosion inhibitor is detennined so as to provide an effective improvement in the resistance of the outer surface of the steel tubular casing to corrosion.
The annular grout layer 10 has a reduced diameter as compared to the known borehok/grout iayericasing stmcture as shown in Figure i. The reduced diameter permits the achievement of costeffective, and technically effective, corrosion inhibition of the outer surface of the casing 54 by incorporation of the corrosion inhibitor, as a substantially unithrm dispersion thereof throughout the thickness of the grout layer in at least one longitudinal region of the grout layer, into the grout formulation.
in one particular example, a welded outer tubular casing having an external diameter of 127mm and a wall thickness of 4mm may be employed to replace a known threaded tubular casing having an external diameter of 139,7mm and a waIl thickness of 10mm, The use of welding to interconnect the tubular casing sections rather than a threaded joint allows the wal! thickness to be reduced from I 0mm to as low as 4mm, although the wail thickness is typically about 5mm, without compromising the structural integrity of the outer tubular casing and the interconnections when used as a component of a borehole heat exchanger.
Furthermore, in addition to reducing the wall thickness, the outside diameter of the outer tubular casing is reduced, while maintaining the maintaining internal fluid capacity of the central bore 62 of the outer tubular casing 54. In this example, the internal fluid diameter may be reduced by only 0.7mm to 119 mm. The mass of steel per unit length of the borehole can be significantly reduced as compared to the known threaded outer tubular casing systems described above, The borehole diameter can correspondingly he reduced from 200mm to 171.5mm.. in addition, the welded outer tubular casing 54 of constant external diameter permits the thickness of the grout 10 barrier to be reduced. The reduced grout thickness not only improves the thermal conductivity of the thermal connection between the borehole heat exchanger and the ground. but also reduces the carbon dioxide (C02) footprint of the installed geothennal energy system.
lit addition to increasing the thermal performance per mete length of the installed borehole heat exchanger (SHE) as compared to the known threaded outer tube, a number of additional benefits are achieved by the welded outer tubular easing of the borehole heat exchanger according to the present invention. The welded outer tubular casing permits a reduction in tubing size, which reduces the cost of the tubing and may increase the speed of installation of the borehole heat exchanger A smaller borehole can permit an increased rate of penetration during installation, and iess cost per metre drilled of the borehole. Correspondingly, there is permitted a reduction in the amount of grout required, the borehole diameter, the size of the drilling equipment required and the volume of drilling fluids required during the drilling operation. A reduced borehole diameter can provide a reduction of waste cuttings volume during the drilling operations and therefore can reduce the impact on the environment from cuttings disposal and reduce the cost of disposal of the cuttings and drilling fluid waste disposal.
Such a reduction in the size of the borehole arid the outer casing can be achieved without sacrificing any loss in Bi-IE volume.
By avoiding threaded couplings between the outer easing sections, there is a significantly reduced in risk of failure of threaded connections, especially over the extended life time of the SI-IS, which is excess of 25 years. Fu*herniorc, no tubing thread lubricant compounds are required during installation, which would otherwise leach into the subsurface environment. Various modifications to the coaxial borehole heat exchanger and installation method of the invention as defined in the appendant claims will be apparent to those skilled in the art.
V
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1322910.9A GB2521623A (en) | 2013-12-23 | 2013-12-23 | Coaxial borehole heat exchangers and installation thereof |
| PCT/EP2014/079185 WO2015097229A2 (en) | 2013-12-23 | 2014-12-23 | Coaxial borehole heat exchangers and installation thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1322910.9A GB2521623A (en) | 2013-12-23 | 2013-12-23 | Coaxial borehole heat exchangers and installation thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201322910D0 GB201322910D0 (en) | 2014-02-12 |
| GB2521623A true GB2521623A (en) | 2015-07-01 |
Family
ID=50114673
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1322910.9A Withdrawn GB2521623A (en) | 2013-12-23 | 2013-12-23 | Coaxial borehole heat exchangers and installation thereof |
Country Status (2)
| Country | Link |
|---|---|
| GB (1) | GB2521623A (en) |
| WO (1) | WO2015097229A2 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7832220B1 (en) * | 2003-01-14 | 2010-11-16 | Earth To Air Systems, Llc | Deep well direct expansion heating and cooling system |
| US20110167819A1 (en) * | 2007-06-28 | 2011-07-14 | Nikola Lakic | Self-Contained In-Ground Geothermal Generator |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0124303A3 (en) * | 1983-04-29 | 1985-07-31 | Halliburton Company | Cement composition for sealing a subterranean formation |
| GB2160306B (en) * | 1984-06-14 | 1987-12-09 | Total Energy Conservation And | Method of geothermal energy recovery |
| CH689402A5 (en) * | 1992-10-13 | 1999-03-31 | Foralith Ag | Method of inserting an earth probe and earth probe. |
| US6702040B1 (en) * | 2001-04-26 | 2004-03-09 | Floyd R. Sensenig | Telescopic drilling method |
| JP3936963B2 (en) * | 2001-10-18 | 2007-06-27 | 独立行政法人産業技術総合研究所 | Underground heat exchanger |
| US8058328B2 (en) * | 2003-11-05 | 2011-11-15 | Nippon Shokubai Co., Ltd. | Cement admixture |
| DE102005005971B3 (en) * | 2004-04-07 | 2006-03-16 | Blz Geotechnik Gmbh | Operating method e.g. for heating building components, involves operating heat extracting plant for heating up construction units and work surfaces with evaporating working material takes up heat over probe system brought into base |
| FR2918086B1 (en) * | 2007-06-26 | 2013-02-08 | Climatisation Par Puits Canadiens | HEAT EXCHANGER VERTICAL BURNER FOR HEATING OR REFRESHING INSTALLATION |
-
2013
- 2013-12-23 GB GB1322910.9A patent/GB2521623A/en not_active Withdrawn
-
2014
- 2014-12-23 WO PCT/EP2014/079185 patent/WO2015097229A2/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7832220B1 (en) * | 2003-01-14 | 2010-11-16 | Earth To Air Systems, Llc | Deep well direct expansion heating and cooling system |
| US20110167819A1 (en) * | 2007-06-28 | 2011-07-14 | Nikola Lakic | Self-Contained In-Ground Geothermal Generator |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2015097229A3 (en) | 2015-10-15 |
| WO2015097229A2 (en) | 2015-07-02 |
| GB201322910D0 (en) | 2014-02-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |