Geothermal probe with mixing elements

Abstract

A geothermal probe for exchanging heat between ground surrounding the geothermal probe, in which the geothermal probe is arranged in the operating state, and a heat transfer fluid includes inflow and outflow pipes. The inflow pipe has an inflow pipe inner surface and the outflow pipe, arranged therein, has an outflow pipe outer surface. Between the inflow pipe inner surface and the outflow pipe outer surface and annular space is formed that is entered by the heat transfer fluid in laminar flow. At least two mixing elements are arranged at a distance from one another in the annular space. The mixing elements bring about a repeated alternation between laminar flow of the heat transfer fluid and mixing.

Claims

1. A geothermal probe for the exchange of heat between a ground surrounding the geothermal probe, in which the geothermal probe is arranged in the operating state, and a heat transfer fluid, comprising: 1.1 an inlet pipe with an inlet pipe inner surface, 1.2 an outlet pipe arranged therein with an outlet pipe outer surface, wherein between the inlet pipe inner surface and the outlet pipe outer surface an annular space is formed, into which the heat transfer fluid laminarly flows, and 1.3 at least two mixing elements which are arranged spaced from one another in the annular space along a longitudinal axis of the outlet pipe, 1.3.1 comprising at least one first part ring disc and one second part ring disc with a part ring surface each, which is delimited by an inner edge, which butts against the outlet pipe outer surface, an outer edge and two free ends, wherein 1.3.1.1 the part ring discs are arranged differently obliquely to an orthogonal plane of the longitudinal axis of the outlet pipe, so that a first flow path with a rotatory component runs over the part ring surfaces about the outlet pipe, 1.3.1.2 one each of the free ends of the first part ring disc and one of the free ends of the second part ring disc are arranged substantially spaced from one another and thus form an opening, through which a second flow path with a component that is parallel to the longitudinal axis of the outlet pipe leads, and 1.3.1.3 the outer edge of the part ring discs with the inlet pipe inner surface forms an annular gap, through which a third flow path with a component along the inlet pipe inner surface lead, 1.3.1.4 the first flow path intersects the second flow path and the third flow path and results in an intermixing of the heat transfer fluid, wherein the distance between the mixing elements is selected so that the heat transfer fluid following the intermixing by one of the mixing elements again flows almost laminarly to the next mixing element, such that a change between intermixing and almost laminar flow of the heat transfer fluid takes place in the geothermal probe.

2. The geothermal probe according to claim 1, wherein the meter volume of the annular space is greater than 8 1.

3. The geothermal probe according to claim 1, wherein the mixing elements are displaceably arranged in the annular space in a direction along the longitudinal axis (x-x).

4. The geothermal probe according to claim 3, wherein the mixing elements each comprise a sleeve with bores, which via grub screws can be arranged in different positions on the outlet pipe.

5. The geothermal probe according to claims 1, wherein the part ring discs of adjacent mixing elements are arranged differently in an orthogonal plane of the longitudinal axis in such a manner that the direction of the rotatory component of the first flow path of the adjacent mixing elements differs.

6. The geothermal probe according to claim 1, wherein the free ends of a part ring disc include among them an angle of 100 to 220.

7. The geothermal probe according to claim 1, wherein the distance between the outer edge of the part ring discs and the inlet pipe inner surface in an orthogonal plane in radial direction to the longitudinal axis amounts to 1 mm to 2.5 mm.

8. A geothermal probe heat circuit, comprising a connection heat circuit with at least one geothermal probe according to claim 1, a consumer heat circuit with a heat pump for satisfying a heat request, and a heat exchanger for transferring heat between the connection heat circuit and the consumer heat circuit, and a circulating pipe for generating a circulation of the heat transfer fluid within the geothermal probe, which causes the heat transfer fluid to circulate at short time intervals independently of a heat request of the consumer heat circuit.

9. A method for operating a geothermal probe heat circuit with a geothermal probe according to claim 1, a circulating pump for generating a circulation of the heat transfer fluid within the geothermal probe, and a consumer heat circuit with a heat pump, wherein the circulating causes the heat transfer fluid to circulate at short time intervals independently of a heat request of the consumer heat circuit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the disclosure are obtained from the following description of an exemplary embodiment which is not to be understood as being restrictive, which is explained in more detail in the following making reference to the figures. In the drawings:

(2) FIG. 1: a perspective representation of a mixing element on an outlet pipe;

(3) FIG. 2: a cross section through an inlet pipe in a region in which a mixing element is arranged;

(4) FIG. 3: a cross section through an inlet pipe, in a region, in which three mixing elements are arranged; and FIG. 4: a schematic drawing of a geothermal probe heat circuit.

DETAILED DESCRIPTION OF THE DRAWINGS

(5) FIG. 1 schematically shows a section of an outlet pipe 18 on which a mixing element 20 is arranged. In the shown exemplary embodiment, the same comprises five part ring discs 22 with a part ring surface 21 each, which is delimited by an outer edge 25, an inner edge 23 and two free ends 26 each.

(6) The part ring discs 22 are arranged differently obliquely to an orthogonal plane of a longitudinal axis x-x of the outlet pipe 18, wherein in each case one of the free ends 26 is arranged spaced from one of the free ends 26 of the adjacent part ring disc 22. Because of this, the two free ends 26 of adjacent part ring discs 22 form an opening 24, which extends in a vertical direction along the longitudinal axis x-x of the outlet pipe 18. The free ends 26 of adjacent part ring disc 22 are substantially arranged spaced from one another and here contact one another only in the region of their outer edge 25. Through the oblique arrangement of the part ring discs 22, the appearance of the mixing element 20 resembles that of a helix winding about the outlet pipe 18 in clockwise direction in a top view in the direction of the longitudinal axis x-x.

(7) FIG. 2 shows a simplified cross section through an inlet pipe 12 of a geothermal probe 10 according to the disclosure in a region in which a mixing element 20 is arranged in the annular space 15 between an inlet pipe inner surface 16 and an outlet pipe outer surface 19. The mixing element 20 shown in FIG. 2 corresponds to the mixing element 20 illustrated in FIG. 1 in a schematic representation. In the cross section it is noticeable that between the outer edges 25 of the part ring discs 22 and the inlet pipe inner surface 16 an annular gap 28 is formed.

(8) In the region of the annular space 15, in which the mixing element 20 is arranged, the heat transfer fluid substantially flows along three different flow paths. Before this, the heat transfer fluid flows towards the mixing element 20 in the annular space 15 in an (approximately) laminar manner. The direction of the heat transfer fluid flowing in a laminar manner is shown by large open arrows. The direction of the arrows corresponds to the inlet direction of the heat transfer fluid.

(9) When the laminar-flow heat transfer fluid in inlet direction strikes the part ring surface 21 of the first part ring disc 22, it is directed over the further part ring surfaces 21 in a rotatory movement about the outlet pipe 18 in clockwise direction. This first flow path is shown as a dashed spiral with arrows about the outlet pipe 18.

(10) Through the openings 24 already shown in FIG. 1 between two part discs 22 a second flow path with a vertical component is obtained, wherein a part leads directly along the outlet pipe outer surface 19. This second flow path in each case is shown by a small open arrow in the opening 24. For the sake of clarity, the representation of the small open arrow was omitted in one of the openings 24a, instead of this a small turbulence 29 is shown, which signifies the intermixing of the heat transfer fluid at this point.

(11) The annular gap 28 between the outer edges 25 of the part circular discs 22 and the inlet pipe inner surface 16 constitutes a third flow path. This is indicated by narrow long arrows. In this region, too, the intermixing of the heat transfer fluid is partly shown by small turbulences 29.

(12) In a connecting region in the lower end of the inlet pipe 12 which is not shown here, the heat transfer fluid flows into the outlet pipe 18. The flow direction within the outlet pipe 18 is shown by a black arrow. It is directed opposite to the inlet direction.

(13) FIG. 3 likewise shows a cross section through an inlet pipe 12. In the shown region, three mixing elements 20I, 20II, 20III are arranged within the annular space 15. The representation of the mixing elements 20I-III in the annular space 15 corresponds to the representation from FIG. 2. It is to be illustrated that the distance between the individual mixing elements 20I, 20II, 20III is selected in such a manner that a substantially laminarly flowing heat transfer fluid, indicated by large open arrows, always strikes the part ring surface 21 of the first part ring disc 22 of the respective mixing elements 20I, 20II, 20III. Furthermore it is noted that the first mixing element 20I brings about a rotatory movement of the heat transfer fluid about the outlet pipe 18 in anti-clockwise direction, while the mixing element 20II causes such in clockwise direction, and the mixing element 20III again conducts the heat transfer fluid about the outlet pipe 18 in anti-clockwise direction. Because of the multiple mixing elements 20I-III, a repeating change between laminar flow and intermixing of the heat transfer fluid takes place.