DE202012003480U1 - geothermal probe - Google Patents

Abstract

Geothermal probe (1), at least consisting of
a main probe (2), which comprises at least:
- An evaporator chamber (2.1), which consists of at least one refrigerant chamber (4.1) of a counterflow evaporator (4) and a closed refrigerant circuit (5) is arranged,
A riser (2.2) which is connected to the lower end (2.21) of the evaporator space (2.1),
- A supply line (2.5), which is connected to the evaporator chamber (2.1) and in the refrigerant circuit (5) is arranged,
- A heat exchanger chamber (2.3), which consists of at least one heat medium chamber (4.2) of the counterflow evaporator (4) and is arranged in a main probe heat medium circuit (6) of a heating means, and
a feeder probe (3), which comprises at least:
- An outer jacket (3.1), which is enclosed on its outer side from the soil,
- A probe gap (3.2) which is at least partially bounded by the inner side of the outer jacket (3.1) and a probe bottom (3.3), in which the main probe (2) is arranged, and
- at least one inlet (7.1), ...

Description

The invention relates to a geothermal probe, which serves to provide geothermal energy.

Such devices for the production of geothermal energy are known in principle from the prior art, whereby there is currently a great need for improved and more efficient geothermal probes for different applications. One of these applications relates to the extraction of mechanical energy from geothermal energy, in particular a relaxation of geothermal evaporated refrigerant is used in a turbomachine for this purpose.

Such known geothermal probes are, for example. In EP 1194 723 B1 and in DE 203 20 409 U1 described. These geothermal probes essentially comprise an inner tube, through which vaporized refrigerant can rise, and a channel arranged around the inner tube, through which liquid refrigerant can be supplied to the lower region of the geothermal probe.

From the DE 10 2005 049 215 A1 is a plant for geothermal energy with a geothermal probe known. This geothermal probe is a so-called "fall probe", ie that liquid refrigerant flows mainly to the outer wall of the annulus to the evaporation chamber. In this case, a throttle valve for adjusting the pressure is arranged at the transition from the annular space and the evaporation space. The outer wall of the annular space is only partially wetted, wherein the maximum wetted surface is only about 25% of the total wettable surface. The primary effect of this is that only a part of the surface is available for the heat transfer to the refrigerant and thus only a corresponding amount of heat per unit time is transferable. The existing potential is thus only insufficiently utilized.

• – Entziehen von Wärme aus einer Wärmequelle, wobei die diese das Erdreich ist;
• – Übertragen der entzogenen Wärme auf ein in einem geschlossenen Wärmekreislauf zirkulierendes Wärmefluid und Verdampfen des Wärmefluids mittels der übertragenen Wärme unter Erhöhung des Druckes im verdampften Wärmefluid; wobei das unter hohem Druck stehende Wärmefluid eine Strömungsmaschine durchströmt und dabei unter Abkühlung und Entspannung Arbeit leistet; das nach dem Durchströmen der Strömungsmaschine entspannte und abgekühlte Wärmefluid wieder kondensiert wird und der Druck des kondensierten Wärmefluids wieder mittels der Wärme der Erdwärme erhöht wird und das Wärmefluid derart ausgewählt ist, dass sich durch Ausnutzung einer Temperaturspreizung mit einer Maximaltemperatur von nicht mehr als 130°C eine Dampfdruckdifferenz von wenigstens 0,5 MPa realisieren lässt.

In addition, in the DE 10 2005 049 215 A1 discloses a method of recovering mechanical energy from heat. This method comprises the steps:

• - removing heat from a heat source, this being the soil;
• - Transferring the extracted heat to a circulating in a closed heat cycle thermal fluid and evaporation of the heat fluid by means of the heat transferred with increasing the pressure in the evaporated heat fluid; wherein the high-pressure thermal fluid flows through a turbomachine while performing work under cooling and relaxation; the condensed and cooled after flowing through the turbomachine heat fluid is condensed again and the pressure of the condensed heat fluid is increased again by means of the heat of geothermal heat and the heat fluid is selected such that by utilizing a temperature spread with a maximum temperature of not more than 130 ° C. can realize a vapor pressure difference of at least 0.5 MPa.

From the EP 1923 569 A1 is another geothermal probe known. This has the following basic structure: a nuclear probe, which comprises at least: an evaporation space and a rising space, which is formed as a riser and is arranged centrally within an outer tube of the core probe. The rising space allows the rise of the evaporation space from the vaporized refrigerant. The sheath probe surrounds the core probe at least radially completely. Between the cylinder wall and the core probe, a gap is present, which is filled with a liquid with heat, namely a water-ethanol mixture.

Suitable refrigerants are those which evaporate at low pressure in a temperature range from 0 ° C to -30 ° C, such as ammonia (NH ₃ ), propane (C ₃ H ₈ ), butane (C ₄ H ₁₀ ), carbon dioxide ( CO ₂ ), etc.

Likewise, combinations of the substances mentioned can be used.

If the temperature of the soil in the area of the evaporation chamber is about 20 ° C, then the refrigerant evaporates. Due to the low density of the gaseous refrigerant this rises independently from the evaporation space via the riser.

If the refrigerant used is ammonia (NH ₃ ), which can damage the environment if it penetrates from the geothermal probe into the surrounding soil, special precautions must be taken. Penetration of ammonia into the surrounding soil is particularly harmful if there is a risk that the ammonia gets into water-bearing layers or outgassing into the atmosphere; this is to be effectively prevented.

From the prior art it is also known that geothermal probes are also used to permanently or temporarily accumulating excess heat energy to enter the probe in the usual manner and deliver to the surrounding soil by heat conduction.

The object of the invention is to provide a geothermal probe, which has a higher efficiency with respect to the heat transfer from the heat medium to the refrigerant, which in technical a simple way realized enlargement of the heat transfer surface and allows a continuous flow of gas of the vaporized refrigerant. If ammonia (NH ₃ ) is used as the refrigerant, the required safety with regard to possible environmental damage should exist.

The object of the invention is achieved by a heat probe with the features according to claim 1.

Essential to the invention is that the geothermal probe at least consisting of a main probe, which comprises at least:
an evaporator space, which consists of at least one refrigerant chamber of a countercurrent evaporator and a closed refrigerant circuit is arranged, a riser, which is connected to the lower end of the evaporator chamber, a supply line which is connected to the evaporator chamber and arranged in the refrigerant circuit is a heat exchanger space, which consists of at least one heat medium chamber of the counterflow evaporator and is arranged in a main probe heat medium circuit of a heating means, and a feeder probe, which comprises at least:
an outer sheath which is enclosed on its outer side by the soil, a probe gap, which is at least partially bounded by the inner side of the outer sheath and a probe bottom, in which the main probe is arranged, and at least one inlet, for the liquid heating means, which in at least one open feeder-probe-heater circuit of a heating means is arranged.

A geothermal probe according to the invention is sunk in a conventional manner from the surface of the earth into a borehole, has an upper end to be arranged in the region of the earth's surface and a lower end to be sunk into the borehole.

The dependent claims 2 to 8 contain advantageous embodiments of the invention without limiting this.

It is preferred that the at least one refrigerant chamber 4.1 through the heat medium chamber 4.2 in countercurrent evaporator 4 is enclosed. This arrangement is particularly effective with respect to the heat transfer to be realized.

It is furthermore preferred that the geothermal probe 1 a measuring and control device 8th has, which is integrated into the process control for providing a continuous gaseous refrigerant flow.

The measured data obtained in the usual manner, for example temperature and pressure data determined by temperature and pressure measuring devices, are used by the measuring and control device in particular to at least the circuits: refrigerant circuit, main probe heat medium cycle and feeder probe Wärmemittel- Circuit, the type to match that over the riser, coming from the evaporator room, as constant as possible media flow is applied. This constant flow of media is particularly necessary to use the geothermal probe according to the invention as part of a continuously operable geothermal recovery plant for generating mechanical energy, this system has at least one turbomachine.

The feeder probe 3 the geothermal probe according to the invention 1 can, at least in a possible accident, as a catch basin for out of the main probe 2 exiting refrigerant fluid, for example ammonia (NH ₃ ) serve.

The feeder probe 3 has an outer jacket 3.1 in particular having a hollow cylindrical shape, and a probe bottom 3.3 , The dimensions of the outer jacket 3.1 are the kind chosen, that is the main probe 2 contactless in the feeder probe 3 bring in.

Functionally, the probe gap 3.2 between the outer jacket 3.1 and the main probe 2 filled with a liquid medium containing at least a liquid heat carrier and an antifreeze.

The antifreeze, such as alcohol or glycol, thereby preventing freezing of the liquid heat carrier, such as water, in this regard, low evaporation temperatures.

This liquid medium is primarily used as a heat transfer medium, which primarily serves the heat conduction, is used, with which geothermal heat to the main probe or excess heat to the main probe and / or out of the geothermal probe is conducted into the surrounding soil by heat conduction. The liquid heating means is thus both in the preferably closed main probe-heating medium cycle 6 and also in the preferably open shuttle probe thermal circuit 7 used according to the invention.

Excess waste heat can thus be conducted in the simplest way in the soil, whereby, for example, the formation of a frost jacket to the geothermal probe 1 repressed or excess heat is stored in the soil.

The suction line 7.1 of the feeder probe heat recovery circuit 7 In addition to its primary function in this circuit, it can also perform the function of completely removing the liquid medium from the probe gap in the event of contamination 3.2 suck. This suction power 7.1 preferably extends to the bottom of the feeder probe 3 ,

The feed 7.1 of the feeder probe heat recovery circuit 7 is preferably in the upper part of the feeder probe 3 arranged.

Alternatively, there is the possibility of more than one inlet 7.1 to use, which can be arranged offset in height. Thus, there is a possibility to introduce different amounts of heat with possibly different temperature level to a desired temperature distribution in the geothermal probe 1 to obtain, for example, is required to a continuous method for operating a geothermal probe 1 to get.

As a liquid medium, for example, a harmless from an environmental point of view water-alcohol mixture, for example. A water-ethanol mixture, a water-glycol mixture or a combination of both serve. The alcohol or glycol prevents freezing of the water in this regard low evaporation temperatures.

The components of the geothermal probe 1 are made of conventional corrosion-resistant materials, which allow as possible a good heat conduction.

The geothermal probe 1 is determined in particular for borehole depths of up to 42 m depth, wherein greater depths in the context of the invention are basically possible, but not technologically necessary.

The object of the invention is also achieved by a geothermal recovery plant with the features of claim 9.

The dependent claims 10 to 11 contain advantageous embodiments of the geothermal recovery plant according to the invention without this limit.

Further features, characteristics and advantages of the present invention will become apparent from the following description of embodiments with reference to the accompanying 1 ,

1 shows an embodiment of a geothermal probe according to the invention.

The embodiment of the geothermal probe according to the invention will be described below with reference to 1 described.

The geothermal probe 1 includes at least one feeder probe 3 , which have a cylindrical base body, the outer sheath 3.1 for example, a steel tube: 355.6 mm × 5.6 mm, and one in the feeder probe 3 arranged main probe 2 , In the radial direction, the feeder probe touches, at least in the installed position 3 and the outer jacket 3.1 not so that there is a gap between them, the probe gap 3.2 , The outer jacket 3.1 is at its lower end 3.11 with the probe bottom 3.3 connected and sealed liquid-tight.

For the purposes of the invention can outer jacket 3.1 and probe bottom 3.3 also be integrally formed, for example, if they are made of a plastic material which allows good heat conduction in the context of the invention.

Usually, the outer jacket 3.1 composed of pipe sections, which are successively sunk and connected in the usual way in the hole in the ground. When sinking into a borehole, the pipe sections, for example, by welding in the case of metallic pipe sections are liquid-tightly interconnected, so that the Zubringersonde 3 forms a liquid-tight cavity to the surrounding soil.

The in the feeder probe 3 preferably centrically arranged main probe 2 extends close to the probe bottom 3.3 and is spaced therefrom.

The main probe 2 , arranged in the feeder probe 3 , requires mechanical fixation, in 1 not shown, this being done in the usual manner.

At least in the functional state of the geothermal probe 1 is at least the probe gap 3.2 filled with a liquid medium; in the exemplary embodiment with about 3,000 liters of a water-glycol mixture.

The liquid medium is chosen in the usual way with regard to the type and composition so that it can escape if it leaves the feeder probe 3 into the ground is no danger to the environment.

In addition, the composition of the liquid medium is chosen so that this at Temperatures of up to -20 ° C and preferably up to -30 ° C in the probe gap 3.2 not frozen. A liquid medium which meets these requirements and is used in the present embodiment is, for example, a mixture of water and glycol (water-glycol mixture) in the ratio of 5: 1 by volume.

The glycol serves as antifreeze to freeze the water in the main probe 2 to avoid.

As an alternative to glycol, any other antifreeze available on the open market can be used, as well as salt water or light oil, which also prevents freezing.

Instead of glycol, however, it is also possible to use other additives which prevent freezing of the water, for example other alcohols or ethanol.

The main probe 2 represents the actual working probe of the geothermal probe 1 It includes, inter alia, an evaporation chamber 2.1 in at least one area of the countercurrent evaporator 4 is arranged. The evaporator room 2.1 , which consists of at least one refrigerant chamber 4.1 a countercurrent evaporator 4 exists, is in a closed refrigerant circuit 5 arranged.

The countercurrent evaporator 4 has a heat transfer chamber 4.2 , which at least one refrigerant chamber 4.1 encloses. The refrigerant chamber 4.1 serves as evaporation chamber 2.1 ,

The countercurrent evaporator 4 is in this embodiment, a multipart counterflow evaporator 4 , which consists of three segments 4.31 . 4:32 and 4:33 , each with 10 KW power, consists, each of which has an analog structure and are arranged and connected in series.

This is the evaporator room 2.1 in this embodiment of three arranged in series portions of the evaporator chamber 2.1 where each of these subregions is in one of the segments 4.31 . 4:32 and 4:33 is arranged. The segments 4.31 . 4:32 and 4:33 of the countercurrent evaporator 4 are connected by connecting lines with each other, which are integral components of the closed refrigerant circuit 5 are. The segments 4.31 . 4:32 and 4:33 are preferably in the lower part of the main probe 2 arranged and by struts and at the probe bottom 3.3 , in 1 not shown, attached.

The countercurrent evaporator 4 has at least one heat exchanger space 2.3 , which consists of at least one heat medium chamber 4.2 of the countercurrent evaporator 4 exists and in a closed main probe-warming-circuit 6 a heating means is arranged.

The heat exchanger room 2.3 consists in this embodiment of three arranged in series portions of the heat exchanger chamber 2.3 where each of these subregions is in one of the segments 4.31 . 4:32 and 4:33 is arranged. The segments 4.31 . 4:32 and 4:33 of the countercurrent evaporator 4 are interconnected by interconnecting lines and are integral parts of the closed main probe heat sink circuit 6 , At the bottom of the segment 4:33 is at the heat exchanger room 2.3 a suction line 6.1 arranged, which for sucking the heating means in the main probe heat medium circuit 6 serves. The suction of the heating agent is thereby realized by at least one conventional suction device, such as a conventional liquid pump, which is also an integral part of the main probe heat medium circuit 6 is like heat exchangers and the like., Which in 1 are not shown. The reflux of the heating agent in the main probe-warming-circuit 6 via an inlet 6.2 , The reflux of the heating agent from an open shuttle probe thermal fluid circuit 7 coming into the probe gap 3.2 via at least one inlet 7.1 ,

In addition, the outer sheath 3.1 , the feeder probe 3 in the range of the first 10 meters, seen from the surface of the earth, with a common thermal insulation 1.11 be provided.

The geothermal probe can be a measuring and control device 8th , in 1 not shown, which is integrated into the process control for providing a continuous gaseous refrigerant flow. This measuring and control device 8th records and evaluates all relevant process data, such as temperature, pressure and volume flows, the geothermal probe 1 in the usual way and in particular regulates the main probe-warming-circuit 6 , Feed probe heat sink circuit 7 and the refrigerant circuit 5 , This makes it possible to ensure the provision of a continuous gaseous refrigerant flow, which is required in particular for use of the geothermal probe as part of a continuously operable plant for generating mechanical energy, in which the generation of mechanical energy primarily by expansion of a gaseous medium in a turbomachine he follows.

Below is the basic operation of the geothermal probe 1 explained in more detail:
The at least two chambers possessing countercurrent evaporator 4 is in the evaporator room 2.1 with the coolant, for example ammonia (NH ₃ ), at a temperature of about -15 ° C flows through, and in the heat exchanger chamber 2.3 filled with a water-glycol mixture at a temperature of about + 4 ° C to + 7 ° C.

Alternatively, any other coolant, e.g. As CO ² , propane, etc., are used as a substitute for NH ₃ , but this reduces the effectiveness and thus the gas flow. Due to the temperature spread of the two liquids in the counterflow evaporator 4 creates a chemical reaction, which provides the required ammonia gas in the result.

The evaporation begins in the flow direction in the first segment 4.31 , the three in series 4.31 . 4:32 and 4:33 switched segments of the countercurrent evaporator 4 (Tube exchanger) and forms wet steam.

This wet steam is in the second segment 4:32 of the countercurrent evaporator 4 (Tube exchanger) again evaporated and in the third segment 4:33 of the countercurrent evaporator 4 (Tube exchanger) transferred for the last evaporation. The pumped amount of the now the last evaporation now gaseous refrigerant in the third segment 4:33 of the countercurrent evaporator 4 is about 60 m ³ / h and is available as saturated steam at a pressure of about 2 to 3 bar.

At the bottom of the third segment 4:33 of the countercurrent evaporator 4 The saturated steam rises naturally through the ascending riser 2.2 to the earth's surface.

LIST OF REFERENCE NUMBERS

1

geothermal probe

2

main probe

2.1

evaporation chamber

2.2

riser

2.21

Riser, lower end

2.3

heat exchanger space

3

Shuttle probe

3.1

outer sheath

3.11

Isolation, thermal

3.2

Probe gap

3.3

probe ground

4

Counterflow evaporator

4.1

Refrigerant chamber

4.2

Heat agent chamber

4.31, 4.32 and 4.33

Segments of the countercurrent evaporator

5

Refrigerant circulation

5.1

Refrigerant line

6

Main probe heat medium circuit

6.1

suction

6.2

Intake

7

Shuttle probe heat medium circuit

7.1

Intake

7.2

suction

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1194723 B1 [0003]
• DE 20320409 U1 [0003]
• DE 102005049215 A1 [0004, 0005]
• EP 1923569 A1 [0006]

Claims (11)

Geothermal probe ( 1 ), at least consisting of a main probe ( 2 ), which comprises at least: - an evaporator space ( 2.1 ), which consists of at least one refrigerant chamber ( 4.1 ) of a countercurrent evaporator ( 4 ) and a closed refrigerant circuit ( 5 ), - a riser ( 2.2 ), which with the lower end ( 2.21 ) of the evaporator space ( 2.1 ), - a supply line ( 2.5 ), which with the evaporator space ( 2.1 ) and in the refrigerant circuit ( 5 ), - a heat exchanger space ( 2.3 ), which consists of at least one heat medium chamber ( 4.2 ) of the countercurrent evaporator ( 4 ) and in a main probe heat cycle ( 6 ) of a heating means, and a feeder probe ( 3 ), which comprises at least: - an outer jacket ( 3.1 ), which is enclosed on its outer side from the soil, - a probe gap ( 3.2 ), which at least partially through the inner side of the outer shell ( 3.1 ) and a probe bottom ( 3.3 ), in which the main probe ( 2 ), and - at least one inlet ( 7.1 ), for the liquid heating means, which in at least one open feeder-probe-heating-circuit ( 7 ) is arranged a heating means. Geothermal probe according to claim 1, characterized in that the evaporator space ( 2.1 ) of three arranged in series portions of the evaporator space ( 2.1 ) consists. Geothermal probe according to claim 1, characterized in that the countercurrent evaporator ( 4 ) a multipart countercurrent evaporator ( 4 ). Geothermal probe according to claim 1, characterized in that the at least one refrigerant chamber ( 4.1 ) through the heat medium chamber ( 4.2 ) in a counterflow evaporator ( 4 ) is enclosed. Geothermal probe according to claim 1, characterized in that the refrigerant (A) in the refrigerant circuit ( 5 ) contains at least ammonia (NH ₃ ). Geothermal probe according to claim 1, characterized in that the heating means (A) in the main probe heat medium circuit ( 6 ) and in the feeder-probe heating-medium circuit ( 7 ) contains at least water and an antifreeze. Geothermal probe according to claim 1, characterized in that the geothermal probe ( 1 ) a measuring and control device ( 8th ), which is integrated into the process controller for providing a continuous gaseous refrigerant flow. Geothermal probe according to claim 1, characterized in that the geothermal probe ( 1 ) is a hermetic safety probe. Geothermal heat recovery plant, this at least one geothermal probe ( 1 ) according to at least one of claims 1 to 8. Geothermal recovery plant according to claim 9, characterized in that it is a continuously operable geothermal recovery plant for generating mechanical energy. Geothermal recovery plant according to claim 9, characterized in that this system has at least one turbomachine.

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