DE102004049571A1 - Ground heat storage reservoir comprises an insulating wall consisting of heat insulating building elements which are arranged side by side and are located in a ground slit filled with a hardenable material - Google Patents

Abstract

The ground heat storage reservoir comprises an insulating wall consisting of heat insulating building elements which are arranged side by side and are located in a ground slit filled with a hardenable material. Independent claims are also included for: (A) a sandwich building element for the proposed storage reservoir; (B) a method for producing the proposed ground heat storage reservoir; (C) a deep well for the proposed ground storage reservoir.

Description

Technical area

The The invention relates to the construction of a geothermal storage tank.

It is known, heat with relatively low temperature (less than 95 ° C, usually less than 60 ° C) in large geothermal storage tanks to "store" and by means of heat exchangers and optionally heat pumps also higher quality recover again.

These Geothermal storage tanks are opposite closed laterally to the surrounding soil and contained in the soil material preferably also water, which due to its high heat capacity especially a lot of energy in the form of heat can record.

One Water content also increases the thermal conductivity of the soil clearly, so that the Heat then better over the heat exchangers in the ground and can be discharged again.

The Production of such storage tanks by means of a pit, whose Concrete walls and with a thermal insulation be provided is expensive.

To below, the storage tanks are usually left open, as heat is lost rises above.

Object of the invention

task The invention is the manufacture and operation of an insulating Geothermal storage basin and the heat supply and extraction devices to simplify it and thus from such a Bekken to cheapen energy gained.

Presentation of the invention

The The object is achieved by the in the characterizing part of the claims and dependent claims 1, 3, 4, 8 and 9 specified characteristics solved.

An essential feature of the invention is the use of sandwich components which, insofar as physically and statically required, consist of one or more protective and weight-bearing layers (US Pat. 1 ) and in any case one or more associated thermal insulation layers ( 2 ) consist. The protective and weighting layers ( 1 ) are preferably made of concrete, with low buoyancy also made of metal.

These sandwich components are for this purpose in a slit wall construction prepared slot ( 3 ) containing the soil mass ( 4 ) of the storage pool surrounds. The sandwich components are in the thermosetting diaphragm wall mass ( 5 ) embedded.

Such Slits can by means of appropriate civil engineering equipment such as excavators or milling in the usual Trench wall construction can be created.

The Sandwich components, which are introduced into this slot, have preferably at least one of these Total weight on that they in a filled with sealing wall mass Slot experienced no boost. Your specific weight is therefore preferred at least as big as that of the embedding mass. Otherwise, they have to cure the they kept surrounding mass submerged by ballast or anchoring become.

In a preferred embodiment, the sandwich component according to the invention consists in cross section only of two or three main layers: protective and weight layer / heat insulation material or protective and weight layer / heat insulation material / protective and weight layer. However, additional thin layers with a different function may also be present, eg barrier layers against moisture ( 6 ).

As thermal insulation materials are z. As polystyrene foam, foam glass, rigid polyurethane foam or evacuated microporous support cores (see, eg EP 1114960 A2 ).

The entire heat-insulating wall ( 7 ) of the geothermal reservoir is made up of smaller adjoining sandwich components. The erection of these plates is preferably carried out by means of traverses or frame structures, as far as the inherent bending stiffness is not sufficient for transport conditions. For deep walls, these components are also arranged one above the other.

In the joint area ( 8th ), they are preferably connected together by suitable means. This can along the slot, for example, on the protective and weight layer mounted sheet pile locks ( 9 ), which ensure that the thermal insulation materials are as close together as possible in a form-fitting manner. The horizontal impacts ( 10 ) of superimposed plates in the case of very deep walls can during insertion into the slot, for example by interception of the lower plate and bolting ( 11a ) are realized with the overlying plate or by in sleeves ( 11c ) within the Be continuous cross section of the sound cross section, milled on the joints ( 11b ).

The distances to the slot wall can be achieved by means of spacers ( 12 ) be respected.

The heat stored in the geothermal reservoir accumulates in the upper part of the basin ( 4 ) and there is a thermal gradient down.

The walls of the geothermal storage tank are guided so deep that virtually no heat escapes down. For this purpose, the wall must shield the area of the reservoir of groundwater currents that can hijack considerable amounts of heat, especially at full storage load by convection. The depth of insulation ( 13 ) is therefore preferably greater than the useful depth ( 14 ) of the memory. The fact that the walls reach down deeply, it is then no longer necessary to provide the reservoir with a bottom.

However, it is possible, for example, in the presence of a water-impermeable layer ( 15 ) in the underground the walls into this layer into lead ( 16 ), so that virtually a hydraulically sealed basin (also 17 ) arises. This is advantageous, above all, in the case of wholly or partly dry, non-binding soils, since this increases their storage capacity and effectiveness when the downwardly closed storage volume thus created (FIG. 17 ) then to above the original groundwater level ( 18 ) is loaded with water addition.

The entry or discharge of heat energy takes place by means of heat exchangers ( 19 ), mostly in either separately prepared self-hardening 20 ) backfilled small bores ( 21 ) or, in part, can also be installed in the slot together with the sandwich component or as part of the sandwich component ( 22 ).

In non-binding soils of sufficient water permeability, instead of the transfer of heat energy by heat conduction between probes and soil, the groundwater itself as a mobile heat transfer medium to the earth body by means of filter wells ( 23 ) and later fed again. Due to the naturally occurring temperature stratification of the water takes place the introduction or removal of warm water at the top of the storage volume, the simultaneous removal or discharge of cold water at the bottom of the storage volume.

The riser ( 24 ) for cold water is preferably also thermally insulated from the surrounding hot water.

The production of such a well, for example, takes place in such a way that after drilling the well ( 25 ) well below the lower edge of the planned Speicherutzhöhe in the protection of a well casing ( 26 ) the well pipe into the hole ( 25 ) is set. The well pipe consists from top to bottom of a at the bottom edge with brackets ( 27 ) and just above it with circumferential, outer sealing collars ( 28 ) provided with an extension tube ( 29 ), a filter tube ( 30 ) and an all-round slit, open at the bottom and not to the borehole sole reaching subset tube ( 31 ).

The monorail ( 32 ) below the planned Speicherutzhöhe is filled through the well pipe in a conventional manner with pile concrete, with an intimate bond to the surrounding soil and to the Untersatzrohr ( 31 ) arises. The above adjoining filter section ( 33 ) is filled with a hydraulically suitable (filter-stable) gravel-sand mixture. Then the drill pipe ( 26 ) to the upper edge of the filter section ( 33 ) pulled up.

A thin, waterproof, low heat-conducting, in the lower area with inside sealing collars ( 34 ) provided pipe ( 35 ) is placed on the consoles ( 27 ), in the alternative to the filter section ( 33 ), put on. This tube ( 35 ) has an outer diameter which is slightly smaller than the inner diameter of the Bohrverrohrung ( 26 ), and it is on its underside with a perforated disc ( 36 ), whose inner diameter is slightly larger than the outer diameter of the attachment tube ( 29 ).

The lower part of the annulus between the top tube ( 29 ) and pipe ( 35 ) is filled at a height of a few meters with swellable mortar of flowable consistency and high early strength ( 37 ). After hardening of the mortar, a circumferentially watertight connection ("concrete seal") is created between the pipes ( 29 ) and ( 35 ).

The drill pipe is now pulled up, the resulting annulus ( 40 ) is filled by the displaced during drilling, now slipping soil. After setting the concrete seal ( 37 ), the above remaining annulus ( 41 ) between the pipes ( 29 ) and ( 35 ) pumped out of water. The here on the lower edge of the perforated disc ( 36 ) acting buoyancy force is due to friction between the pipe ( 35 ) on the one hand and the surrounding soil on the other hand, or - by means of a support tube ( 31 ) - through the network ( 42 ) between concrete foot ( 32 ) and soil carried off. The emptied annulus ( 41 ) is dried if necessary with hot air and with egg free-flowing, sufficiently temperature- and pressure-resistant insulation ( 38 ). Finally, the riser ( 24 ) with a submersible pump installed at its lower end ( 39 ) introduced.

• – kein Aushub, kein Verbau, keine Wiederverfüllung erforderlich
• – die einbettende Dichtwandmasse ist nach dem Aushärten noch plastisch verformbar, Risse heilen sich selbst
• – die Dichtwand ist wasserdicht (k_S ca. 10^–9 bis 10^–10 m/s); Wasser kann bei wasserdurchlässigen Böden zur Verbesserung der Speicherfähigkeit auch nach der Wandherstellung in das Speicherbecken zugefügt werden, sofern die Dichtwandunterkante in grundwasserstauenden Boden einbindet
• – praktisch in allen Böden und bis in große Tiefen (>50 m) herstellbar, mit Fräsen auch im Felsgestein
• – ein Teil der Wärmeaustauscher kann gleich mit der Sandwichplatte eingebaut werden, so daß weniger Bohrungen benötigt werden.

The construction according to the invention has the following advantages:

• - No excavation, no shoring, no refilling required
• - The embedding sealant mass is still plastically deformable after curing, cracks heal themselves
• - the sealing wall is watertight (k _S approx. 10 ^-9 to 10 ^-10 m / s); Water can be added in water-permeable soils to improve the storage capacity even after the wall has been produced in the reservoir, provided that the bottom edge of the sealing wall encloses groundwater-damaging soil
• - practically in all soils and down to great depths (> 50 m) can be produced, with milling in the rock
• - A part of the heat exchanger can be installed equal to the sandwich plate, so that fewer holes are needed.

The Figures give exemplarily a possible embodiment the invention again:

1 shows in section the simple case of a sandwich component, which consists essentially of a heat-insulating layer ( 2 ) and a weighting and stabilizing layer ( 1 ) consists. In addition, it has in this case a water and water vapor-tight, sufficiently temperature-resistant layer ( 6 ) on.

2 shows in vertical section such elements, installed in a slot ( 3 ), which is also optional ( 16 ) into a waterproof layer ( 15 ) can descend.

3 shows in horizontal section two adjoining elements in a corner region, here exemplified by sheet pile locks ( 9 ) are connected.

4 and 5 show in vertical section how two sandwich components can be arranged one above the other and connected to one another.

6 shows the location of heat exchangers ( 19 respectively. 22 ) relative to a sealing and insulating wall according to the invention.

7 also shows an upwardly insulated storage tank which is watertight downwards, whereby the water level ( 18 ) can be raised in memory over the groundwater level outside. The storage tank has wells for heat supply and extraction ( 23 ) on.

9 shows a possible thermally insulated well and 8th an intermediate stage in the manufacture thereof, in which the casing of the borehole is being progressively pulled and a sealing concrete seal has been produced at the foot of the extension pipe. This sealing seal allows the space between the top tube ( 29 ) and pipe ( 35 ) and then fill with insulating material before the well casing ( 26 ) is pulled further.

1

protective and weighting layer

2

Thermal insulation layer

3

slot

4

Including soil mass

5

Slit wall material

6

junction against moisture

7

all Wall of geothermal storage tank

8th

joint area between two sandwich components

9

sheet pile lock

10

joint area with one above the other arranged sandwich components

11a

bolting

11b

Steel threaded rod

11c

shell

12

spacer

13

Dämmtiefe

14

Usable

15

water-impermeable layer

16

Diaphragm wall base in a water-impermeable layer

17

storage volume

18

water level inside the store

19

heat exchangers

20

supporting liquid for small bore

21

small hole

22

heat exchangers combined with sandwich component

23

filter wells

24

riser

25

drilling for filter wells

26

well casing

27

console

28

sealing collar

29

tower tube

30

filter pipe

31

Pedestal tube

32

binding line, concrete base

33

filter section

34

sealing collar

35

pipe

36

perforated disc

37

Betonplombe

38

insulation

39

submersible pump

40

annulus

41

annulus above the concrete seal

42

composite between concrete foot and soil

Claims (10)

A geothermal reservoir with a heat-insulating lateral wall delimiting the basin from the environment, characterized in that said wall consists of a number of contiguous heat-insulating components located in a buried space filled with hardening material. Storage tank according to claim 1, characterized that it at the heat-insulating Structural elements to prefabricated parts in sandwich construction of thermally insulating as well as protective and / or weighted material. Sandwich component for a storage tank after at least one of the claims 1 and 2, characterized in that it is in the protective and / or weighting material of the sandwich component to concrete or metal. Sandwich component for a storage tank after at least one of the claims 1 and 2, characterized in that it is in the heat-insulating Material of the sandwich component to polystyrene foam, foam glass, Rigid polyurethane foam and / or evacuated microporous support cores is. Sandwich component according to at least one of claims 3 and 4, characterized in that it viewed in cross section from a protective and / or weighting Layer and an associated heat-insulating layer consists. Sandwich component according to at least one of claims 3 and 4, characterized in that it viewed in cross section from a protective and / or weighting Layer and an associated heat-insulating layer and a so connected protective and / or weighting layer. Sandwich component according to at least one of claims 3 to 6, characterized in that it on the side facing the storage inside over a Wärmezufuhr- and / or heat removal device features. Process for the production of a geothermal storage tank with a thermo-isolating the basin from the environment lateral wall, characterized in that the heat-insulating lateral wall means Trench wall method is prepared, wherein subsequently in the slit made in such a way closely adjacent sandwich components be sunk, consisting of at least one protective and / or weighting Layer and at least one heat-insulating Layer exist. Deep well for a geothermal storage tank, thereby characterized in that Heat insulation buoyant is installed dry, hydraulic in the operating condition against the ground ge is encapsulated and that the encapsulating material no significant heat conduction along the Riser or downpipe permits. Well according to claim 9, characterized that his Opposite the climbing or downpipe is thermally insulated from the surrounding soil.