DE19929697A1 - Filling material for ground heat transmitter comprises up to 50 per cent by weight of powder, granulate-form graphite or distended graphite with granule sizes between 0.001 mm and 1 mm - Google Patents

Filling material for ground heat transmitter comprises up to 50 per cent by weight of powder, granulate-form graphite or distended graphite with granule sizes between 0.001 mm and 1 mm

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Publication number
DE19929697A1
DE19929697A1 DE19929697A DE19929697A DE19929697A1 DE 19929697 A1 DE19929697 A1 DE 19929697A1 DE 19929697 A DE19929697 A DE 19929697A DE 19929697 A DE19929697 A DE 19929697A DE 19929697 A1 DE19929697 A1 DE 19929697A1
Authority
DE
Germany
Prior art keywords
graphite
weight
distended
granulate
powder
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Withdrawn
Application number
DE19929697A
Other languages
German (de)
Inventor
Hans-Peter Ebert
Volker Drach
Jochen Fricke
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bayerisches Zentrum fuer Angewandte Energieforschung eV
ZAE Bayern Bayerisches Zentrum fuer Angewandte Energieforschung eV
Original Assignee
Bayerisches Zentrum fuer Angewandte Energieforschung eV
ZAE Bayern Bayerisches Zentrum fuer Angewandte Energieforschung eV
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Bayerisches Zentrum fuer Angewandte Energieforschung eV, ZAE Bayern Bayerisches Zentrum fuer Angewandte Energieforschung eV filed Critical Bayerisches Zentrum fuer Angewandte Energieforschung eV
Priority to DE19929697A priority Critical patent/DE19929697A1/en
Priority to DE19958765A priority patent/DE19958765A1/en
Priority to EP00112861A priority patent/EP1065451B1/en
Priority to DE50004133T priority patent/DE50004133D1/en
Priority to AT00112861T priority patent/ATE252713T1/en
Publication of DE19929697A1 publication Critical patent/DE19929697A1/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • 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
    • F24T10/15—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 using bent tubes; using tubes assembled with connectors or with return headers
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00663—Uses not provided for elsewhere in C04B2111/00 as filling material for cavities or the like
    • 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)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Ceramic Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Combustion & Propulsion (AREA)
  • Structural Engineering (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)

Abstract

The filling material for a ground heat transmitter comprises up to 50 per cent by weight of powder or granulate-form graphite or distended graphite with granule sizes between 0.001mm and 1 mm. A ground heat probe accumulator is pushed into the ground (1), lying freely beneath a cultivated earth area (2). Then, various earth bores (3) are sunk, space apart by 1.5 to 2.5 m, the bore diameter being 20 cm and the bore depth 50 to 70 m. All bore holes accommodate U-shaped probes, U-shaped pipe conduits (4) being used. The pipe conduits form part of a network and are connected to a heat collector, suitable heating bodies and a hot water tank. One conduit part (5) forms the forward flow and another conduit part (7) the back flow of the network. A heat insulation (8) protects against excessive heat loss upwards.

Description

Gegenstand der Erfindung ist ein Bohrlochverfüllmaterial für Erdwärmesonden nach Patentanspruch 1. Durch den Einsatz von Graphit als Bestandteil des Verfüllmaterials wird dessen Wärmeleitfähigkeit erhöht und somit die Fähigkeit der Erdwär­ mesonde verbessert, große Wärmeleistungen zu übertragen.The invention relates to a borehole filling material for Geothermal probes according to claim 1. By using Graphite becomes part of the backfill material Thermal conductivity increases and thus the ability of geothermal energy mesonde improved to transmit large heat outputs.

Stand der TechnikState of the art

Zur Langzeitspeicherung von Wärmeenergie stellt der Erdwärme­ sondenspeicher eine erfolgreich eingesetzte Variante der erdgekoppelten Wärmepumpen dar. Die Erdwärmesonden ermögli­ chen die Zuführung und Abführung von Wärmeenergie im Erdreich durch Wasser oder einer anderen Wärmeträgerflüssigkeit in einem geschlossenen Kreislauf.Geothermal energy provides long-term storage of thermal energy probe storage a successfully used variant of the geothermal heat pumps. The geothermal probes allow the supply and discharge of thermal energy in the ground by water or another heat transfer fluid in a closed cycle.

In geeigneten Bodenzonen werden vertikale Löcher ausgebohrt, die in der Regel eine Länge von weit mehr als 10 m aufweisen und deren Durchmesser ungefähr 20 cm beträgt. In diese Bohr­ löcher werden geeignete Wasserrohre (z. B. U-Rohre oder Koa­ xialrohre aus PVC) eingesetzt. Mit einem Bohrlochverfüllmate­ rial aus speziellem Beton wird der thermische Kontakt zwi­ schen der Erdwärmesonde und dem umgebenden Erdreich gewähr­ leistet und die Rohre mechanisch fixiert.Vertical holes are drilled in suitable soil zones, which generally have a length of far more than 10 m and whose diameter is approximately 20 cm. In this Bohr Holes become suitable water pipes (e.g. U pipes or Koa xial pipes made of PVC). With a borehole filler rial made of special concrete, the thermal contact between the geothermal probe and the surrounding earth performs and mechanically fixes the pipes.

Als Verfüllmaterial werden üblicherweise Mischungen aus Wasser, Bentonit, Zement und Quarzsand verwendet. Die Be­ standteile Wasser, Bentonit und Zement bilden das eigentliche Bindemittel; die Zusammensetzung dieser Mischung bewirkt im abgebundenen Zustand im wesentlichen die mechanische und chemische Resistenz des Verfüllmaterials. Der Quarzsand dient als Füllstoff und zur Erhöhung der Wärmeleitfähigkeit der Gesamtmischung. Die Sandkörnchen werden nach dem Abbinden der Bindemittelmischung (Wasser, Bentonit, Zement) mehr oder weniger von dem Bindemittel eingehüllt. Durch leichte Schrumpfung des Bindemittels beim Aushärteprozeß und unter­ schiedliche Ausdehnungskoeffizienten von Bindemittel und Quarzsand ist eine vollständige Anlagerung des Bindemittels an die Oberfläche des Sandkorns nicht immer gegeben. Es treten damit thermische Kontaktwiderstände an den Grenzen zwischen Kornoberfläche und Bindemittel auf.Mixtures of are usually used as backfill material Water, bentonite, cement and quartz sand are used. The Be Ingredients water, bentonite and cement form the real thing  Binder; the composition of this mixture causes set state essentially the mechanical and chemical resistance of the backfill material. The quartz sand serves as a filler and to increase the thermal conductivity of the Total mix. The grains of sand are removed after the setting Binder mixture (water, bentonite, cement) more or less enveloped by the binder. By light Shrinkage of the binder during the curing process and under different expansion coefficients of binder and Quartz sand is a complete accumulation of the binder not always given to the surface of the grain of sand. It thermal contact resistances occur at the limits between grain surface and binder.

Quarzsand besitzt eine Festkörperwärmeleitfähigkeit von etwa 1,5 W/(mK); das abgebundene Verfüllmaterial hat jedoch wegen der oben genannten Probleme bei der thermischen Ankopplung von Bindemittel und Sand, sowie wegen der geringen Wärmeleit­ fähigkeit der bindenden Komponenten Bentonit und Zement eine effektive Gesamtwärmeleitfähigkeit von etwa nur 1 W/(mK). Diese relativ niedrige Wärmeleitfähigkeit vermindert die Leistungsfähigkeit der Erdwärmesonde, d. h. die Fähigkeit große Wärmeleistungen zu übertragen. Dies ist entscheidend für die Effizienz des gesamten Speichersystems.Quartz sand has a solid-state thermal conductivity of approximately 1.5 W / (mK); however, the set backfill material is due to of the above problems with thermal coupling of binders and sand, and because of the low thermal conductivity ability of the binding components bentonite and cement effective total thermal conductivity of only 1 W / (mK). This relatively low thermal conductivity reduces the Efficiency of the geothermal probe, d. H. the ability transfer large heat outputs. This is crucial for the efficiency of the entire storage system.

Aufgabe der ErfindungObject of the invention

Die Aufgabe der Erfindung ist es, die Wärmeleitfähigkeit des Verfüllmaterials für Erdwärmesonden merklich zu erhöhen. Als Lösung des Problems wird die Zumischung von Graphit vorgeschlagen. Graphit besitzt in reiner Form eine Wärmeleit­ fähigkeit von etwa 170 W/(mK). Der Quarzsand im Verfüllmate­ rial kann zum Teil oder vollständig durch Graphitpulver ersetzt werden. Um die mechanischen Eigenschaften des Ver­ füllmaterials nicht zu verändern, kommt bevorzugt Graphitpul­ ver bzw. Graphitgranulat zum Einsatz, deren Partikelgröße etwa 0,1 bis 1 mm beträgt, das entspricht in etwa der Korn­ größe des üblicherweise verwendeten Sandes. Graphitpulver in grober Fraktion ist auch billiger erhältlich als feinkörniges Graphit.The object of the invention is to improve the thermal conductivity of the Noticeably increase the backfill material for geothermal probes. The solution to the problem is the addition of graphite suggested. In its pure form, graphite has thermal conductivity ability of about 170 W / (mK). The quartz sand in the backfill rial can be partially or completely by graphite powder be replaced. To the mechanical properties of the Ver Graphite pulp is preferred, not to change the filler material  ver or graphite granules are used, their particle size is about 0.1 to 1 mm, which corresponds approximately to the grain size of the commonly used sand. Graphite powder in coarse fraction is also available cheaper than fine-grained Graphite.

Um eine noch bessere thermische Anbindung der Graphitparti­ kel an das umgebende Bindemittelmaterial zu gewährleisten wird vorgeschlagen, als Graphit Blähgraphit zu verwenden. Blähgraphit besitzt zwar durch die offenporige schaumartige Struktur eine niedrigere Wärmeleitfähigkeit als das massive Graphitkorn, verbindet sich aber aufgrund seiner elastischen Eigenschaften und seiner Oberflächenstruktur inniger mit dem umgebenden Bindemittel.For an even better thermal connection of the graphite parts ensure the surrounding binder material it is proposed to use expanded graphite as the graphite. Expandable graphite has foam-like due to the open-pore Structure a lower thermal conductivity than the massive Graphite grain, but combines due to its elastic Properties and its surface structure more intimate with the surrounding binder.

Das Bindemittel dringt zum Teil in das Blähgraphitteilchen ein; die elastischen Eigenschaften des Blähgraphits kompen­ sieren das Problem der unterschiedlichen Ausdehnungskoeffizi­ enten von Bindemittel und Graphitteilchen und reduzieren damit den Effekt der thermischen Kontaktwiderstände an den Korngrenzen.The binder partially penetrates the expandable graphite particle on; compensate for the elastic properties of expanded graphite the problem of the different expansion coefficients ent of binders and graphite particles and reduce thus the effect of the thermal contact resistances on the Grain boundaries.

Die typische Zusammensetzung des Verfüllmaterials besteht aus etwa 50 Gew.-% (Gewichtsprozent) Wasser, 10 Gew.-% Bento­ nit, 10 Gew.-% Zement und 30 Gew.-% Sand. Wenn der Sand kom­ plett durch Graphit ersetzt wird erreicht man eine Wärme­ leitfähigkeit von mehr als 2 W/(mK), d. h. durch den Einsatz des Graphits im Verfüllmaterial wird die Wärmeleitfähigkeit verdoppelt.The typical composition of the backfill material exists from about 50% by weight (weight percent) water, 10% by weight bento nit, 10 wt% cement and 30 wt% sand. When the sand comes If graphite is replaced, heat is achieved conductivity of more than 2 W / (mK), d. H. because of the engagement of the graphite in the backfill material becomes the thermal conductivity doubled.

An der gesamten Zusammensetzung des Verfüllmaterials kann Graphit zwischen 5 Gew.-% und 50 Gew.-% betragen.On the entire composition of the backfill material Graphite be between 5 wt .-% and 50 wt .-%.

Claims (3)

1. Verfüllmaterial für Erdwärmesonden, dadurch gekennzeich­ net, daß 10 Gewichtsprozente bis 50 Gewichtsprozente der Zusammensetzung des Verfüllmaterials aus pulver- oder granulatförmigem Graphit oder Blähgraphit bestehen.1. Backfill material for geothermal probes, characterized in that 10 percent by weight to 50 percent by weight of the composition of the backfill material consist of powdered or granular graphite or expanded graphite. 2. Verfüllmaterial nach Anspruch 1, dadurch gekennzeichnet, daß der Graphit oder der Blähgraphit Korngrößen zwischen 0,1 mm und 1 mm aufweist.2. Filling material according to claim 1, characterized in that the graphite or the expanded graphite grain sizes between 0.1 mm and 1 mm. 3. Verfüllmaterial nach Anspruch 1 oder 2, dadurch gekenn­ zeichnet, daß das Bindemittel im Verfüllmaterial aus min­ destens zwei der Bestandteile Wasser, Bentonit, Zement und Sand besteht.3. backfill material according to claim 1 or 2, characterized records that the binder in the backfill material from min at least two of the components water, bentonite, cement and there is sand.
DE19929697A 1999-06-29 1999-06-29 Filling material for ground heat transmitter comprises up to 50 per cent by weight of powder, granulate-form graphite or distended graphite with granule sizes between 0.001 mm and 1 mm Withdrawn DE19929697A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
DE19929697A DE19929697A1 (en) 1999-06-29 1999-06-29 Filling material for ground heat transmitter comprises up to 50 per cent by weight of powder, granulate-form graphite or distended graphite with granule sizes between 0.001 mm and 1 mm
DE19958765A DE19958765A1 (en) 1999-06-29 1999-12-07 Backfill material containing graphite for geothermal heat exchangers and earth power cables
EP00112861A EP1065451B1 (en) 1999-06-29 2000-06-17 Filling material comprising graphite for ground heat exchanger
DE50004133T DE50004133D1 (en) 1999-06-29 2000-06-17 Backfill material containing graphite for geothermal heat exchangers
AT00112861T ATE252713T1 (en) 1999-06-29 2000-06-17 GRAPHITE-CONTAINING FILLING MATERIAL FOR GROUND HEAT EXCHANGERS

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19929697A DE19929697A1 (en) 1999-06-29 1999-06-29 Filling material for ground heat transmitter comprises up to 50 per cent by weight of powder, granulate-form graphite or distended graphite with granule sizes between 0.001 mm and 1 mm

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DE19929697A1 true DE19929697A1 (en) 2001-01-04

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DE19929697A Withdrawn DE19929697A1 (en) 1999-06-29 1999-06-29 Filling material for ground heat transmitter comprises up to 50 per cent by weight of powder, granulate-form graphite or distended graphite with granule sizes between 0.001 mm and 1 mm

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10317664B3 (en) * 2003-04-17 2004-10-28 Perforator Gmbh Process for inserting geothermal probe into an underground borehole comprises decoupling a hollow bore screw from, guiding the probe into the screw, removing the tip from the screw, removing the screw and introducing a filler
DE102011108821A1 (en) 2011-07-29 2013-01-31 Bayerisches Zentrum für Angewandte Energieforschung e.V. Filling material, useful e.g. for underground cable, comprises three materials, where first material is base material, preferably cement and/or bentonite, second material is heat-conducting particle, and third material is displacer
DE102015101342A1 (en) * 2015-01-29 2016-08-04 Universität Kassel Earth line bedding material and grounding area
CN108088102A (en) * 2017-11-17 2018-05-29 绿城装饰工程集团有限公司 A kind of corrugated stainless steel tubing geothermal source heat-exchange system and its setting method

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10317664B3 (en) * 2003-04-17 2004-10-28 Perforator Gmbh Process for inserting geothermal probe into an underground borehole comprises decoupling a hollow bore screw from, guiding the probe into the screw, removing the tip from the screw, removing the screw and introducing a filler
DE102011108821A1 (en) 2011-07-29 2013-01-31 Bayerisches Zentrum für Angewandte Energieforschung e.V. Filling material, useful e.g. for underground cable, comprises three materials, where first material is base material, preferably cement and/or bentonite, second material is heat-conducting particle, and third material is displacer
DE102015101342A1 (en) * 2015-01-29 2016-08-04 Universität Kassel Earth line bedding material and grounding area
EP3050860B1 (en) * 2015-01-29 2021-03-03 Universität Kassel Earth line bedding material and earth line section
CN108088102A (en) * 2017-11-17 2018-05-29 绿城装饰工程集团有限公司 A kind of corrugated stainless steel tubing geothermal source heat-exchange system and its setting method

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