geothermal absorber

Abstract

Ground source heat absorber with a cylindrical base body, characterized in that the ground source heat absorber is a prefabricated module for ground source heat absorption, that a fluid-operated heat exchanger (10) is housed within the module base body (1), and that the module has a head arrangement (2) with the aid of which the heat exchanger (10) of the module can be connected to a heat consumer.

Description

[0001] The present invention relates to a ground-source heat absorber with a cylindrical base body and a method for manufacturing the same.

[0002] Several types of devices for extracting energy from near-surface soil are currently considered state of the art. One such device is the ground source heat pump, which is installed vertically in the ground. The ground source heat pump has an outer diameter of 0.5 m. It features a helical PE pipe measuring 25 m x 2.5 m. The helix has a straight pipe length of 55 m. The heat transfer fluid requirement is relatively high, at approximately 35 l / kW. Extraction rates of 500 W / heat pump have been measured. With the required installation spacing of 4 m, this results in an area-specific extraction rate of approximately 40 W / m² at a fluid temperature of -3°C / 0°C. Consequently, ground source heat pumps are not expected to have a significant market opportunity.

[0003] These devices, also known as probes, are available in lengths of 15 m or 30 m. These lengths mean that complete assembly of the probes in a vertical position is only possible on-site, requiring the provision of appropriate lifting equipment. Welding the components of such earth energy baskets can and must only be carried out by trained, certified professionals.

[0004] In all state-of-the-art systems, the heat extraction capacity is relatively low, they exhibit insufficient economic efficiency, and the energy obtained is provided at a low and therefore inefficient temperature level for a heat pump as a form of heat consumer.

[0005] The object of the present invention is to eliminate these and other disadvantages of the prior art.

[0006] This problem is solved according to the invention as defined in the characterizing part of claim 1.

[0007] The aforementioned problem is also solved by a method which is defined in the characterizing part of claim 11.

[0008] The following section provides a more detailed explanation of embodiments of the present geothermal heat absorber – also referred to as absorber in the following description – with reference to the accompanying drawings. These show: Fig. 1 in a side view of the present geothermal heat absorber, wherein the central area of ​​a cylindrical shell of the absorber has been omitted, Fig. 2. In the future, the geothermal heat absorber according to Fig. 1, Fig. 3. Perspective view of the front of a connection area of ​​the absorber in Fig. 2, Fig. 4 in a front view the connection area Fig. 3 Fig. 5 in a cut AA the connection area of ​​the absorber from Fig. 4, Fig. 6 in a section BB the connection area of ​​the absorber from Fig. 4, and Fig. 7 in a perspective view the rear side of the connection area of ​​the absorber Fig. 3.

[0009] In Fig. Figure 1 shows a side view of the present ground-source heat absorber. This absorber has a cylindrical base and is a prefabricated module for ground-source heat absorption. One of the end sections of the cylindrical module base 1 is assigned a head assembly 2, which allows the ground-source heat absorber to be connected to surrounding devices, such as heat consumers – i.e., devices that extract heat from the ground-source heat absorber. In the illustrated case, a termination piece 3 is assigned to the opposite end section of the module base 1. A central area of ​​the module base 1 was Fig. 1 omitted so that the components of the geothermal absorber located inside this module body 1 can be at least partially visible.

[0010] Fig. Figure 2 shows the geothermal heat absorber from perspective. Fig. 1. The one in Fig. 1 and Fig. The absorber shown in section 2 can also be called a module for short. In principle, it is also possible to connect such modules in series, for example. This allows the construction of geothermal absorbers whose length is adapted to the local conditions of the installation site. The geothermal absorber can expediently consist of several interconnected modules, each with a head assembly 2 at both ends of the module base 1. Modules or rows of modules could also be connected in parallel. The modules of the geothermal absorber are arranged or joined together horizontally (i.e., in a plane), vertically (i.e., perpendicular to each other), or diagonally (i.e., perpendicular to each other) in the ground. The second head assembly 2 can have a different number of openings (described in detail later) than the first head assembly 2 of the same module.

[0011] The cylindrical module base 1 is made of solid material. It is advantageous for the cylindrical module base 1 to be formed from a metal tube, as metals are known to be good heat conductors. Alternatively, to save weight, the module base 1 can be a hollow cylinder made of thin-walled aluminum. The module base 1 could also be made of polyethylene (PE) or high-density polyethylene (HDPE) for easier assembly of the geothermal heat absorber.

[0012] The head assembly 2 and the end piece 3 are either integrally connected to the module base 1 or are liquid-tightly connected to it. This allows the interior of the module to be filled with a liquid. Such measures ensure efficient heat transfer from the surrounding soil to the components of the heat absorber located inside the module.

[0013] Fig. Figure 3 shows the head arrangement 2 of the module from a perspective view. Fig. 1 and Fig. 2. The head assembly 2 has an annular wall 21, which has the shape of a wide ring. The thickness of the wall of this annular wall 21 is comparable to the thickness of the wall of the cylindrical module base body 1. The axis E of the annular wall 21 lies on an axis E, as shown in Fig. 1 and Fig. Figure 4 shows that this annular wall 21 and the cylindrical module base 1 are common to each other. In the illustrated case, one of the lateral edge sections 22 of the annular wall 21 is firmly connected to the cylindrical module base 1. Either the annular wall 21 is integral with the cylindrical module base 1, or these components of the ground source heat absorber are fluid-tightly connected to each other.

[0014] The remaining area of ​​the ring wall 21 projects from the module base body 1. The opposite, free, ring-shaped edge section 23 of the area of ​​the ring wall 21 projecting from the module base body 1 has a first indentation 24 and a second indentation 25. In the illustrated case, the contour of the respective first indentation 24 and the second indentation 25 has the shape of the capital letter U. In the illustrated case, a first leg 26 and a second leg 27 of this U-shape, extending from the web 28 connecting these legs 26 and 27, run parallel to each other. The first indentation 24 is located in the upper area of ​​the ring wall 21. The second indentation 25 is offset from the first indentation 24 by 90 degrees counterclockwise.

[0015] The head assembly 2 further comprises a transverse wall 31 that extends transversely inside the annular wall 21. This transverse wall 31 is located at intervals from both the first, continuous edge portion 22 of the annular wall 21 and the second annular edge portion 23 of the annular wall 21, which has the first indentation 24 and second indentation 25. Passages for liquids are provided in this transverse wall 31. Each of these passages has an opening 32 – as shown in Fig. 7 shown - in the transverse wall 31. Both this transverse wall 31 and the end piece 3 are dished ends 6 - as in Fig. As shown in Figure 1, the end piece 3 comprises a curved dished end wall 4 and a seam 5 and is fluid-tight, bonded, or welded to the module base body 1. In combination with the transverse wall 31 of the head assembly 2, the absorber according to the invention forms a tank for a storage medium. Naturally, the end piece 3 can also be integrally formed with the module base body 1.

[0016] The head arrangement 2 in Fig. 3 and Fig. Figure 4 also features tubular openings 35, 36, 37, and 38. The first opening 35 is located in the central area of ​​the transverse wall 31. The second opening 36 is located to the side of the first opening 35, so that these openings 35 and 36 lie in a common horizontal plane. In the Fig. 3 and Fig. In the case shown in Figure 4, the second passage 36 is located to the left of the first passage 35. The third passage 37 is located above the first passage 35. Finally, the fourth passage 38 is also located above the first passage 35, but to the side of the third passage 37. The angular distance between the third passage 37 and the fourth passage 38 is expediently 45 degrees clockwise.

[0017] Fig. Figure 5 shows a section A - A through the head arrangement 2. Fig. 4. The Fig. Figure 6 shows a section B - B through the head arrangement 2. Fig. 4. The Fig. Figure 7 shows the rear side of head assembly 2 in perspective. Fig. 3. The first passage 35, the second passage 36 and the fourth passage 38 have tubular nozzles 30 which - as in Fig. 5 and Fig. 6 shown - pass through the transverse wall 31 of the head arrangement 2. Fig. Figure 6 further shows that a wall section 34 of the transverse wall 31 runs between the nozzles 30. Accordingly, the nozzle 30 of the passages 35, 36, and 38 consists of a first tubular section and a second tubular section 39. The first tubular passage section is located on the outside of the transverse wall 31. The second tubular section 39 is located on the inside of the transverse wall 31. In the illustrated case, these sections 39 are integral with the transverse wall 31. The opening 32 in the transverse wall 31 is limited or defined by the clear cross-section of the tubular sections 39.

[0018] A tubular extension 40 projects coaxially from the inner tubular section 39. Advantageously, these two components of the absorber are formed in one piece. The inner diameter of the extension 40 corresponds to the inner diameter of the inner tubular section 39. The outer diameter of the extension 40 is smaller than the outer diameter of the inner tubular section 39. The surface of the extension 40 is cylindrical. This allows one of the end portions of one of the tubular components of the ground-source heat absorber located in the module base 1 to be attached to this extension 40 and firmly connected to this section 39. The diameter of the interior in the outer tubular passage section decreases slightly from the outer opening of this passage section towards the transverse wall 31. The Fig. 3 and Fig. The third passage 37 shown in Figure 7 does not have an inner tubular section 39 located on the inside of the transverse wall 31. The third passage 37, located on the outside of the transverse wall 31, terminates with the opening 32 in the transverse wall 31, as shown in Figure 7. Fig. 7 shown.

[0019] Inside the module is a fluid-cooled heat exchanger 10. This heat exchanger 10 comprises a coil extending within the module body 1 between the head assembly 2 and the end piece 3. A tube, preferably made of metal, has been formed into the coil. The outer diameter of the coil turns corresponds essentially to the inner diameter of the module body 1 of the ground source heat absorber. Advantageously, the outer diameter of the coil turns in their relaxed state is even slightly larger than the inner diameter of the module body 1 of the absorber. When such a coil is then inserted into the interior of the module body 1 of the absorber, the sections of the coil turns located on the inner wall of the module body 1 are subjected to a preload on the inner wall of the housing. This significantly improves the heat transfer from the module body 1 to the tube wall of the coil.

[0020] The heat exchanger 10 further comprises an inlet pipe 12, as shown in Fig. 1 and Fig. Figure 5 shows the introduction of an operating fluid into the interior of the heat exchanger 10. This operating fluid acts as a heat transfer fluid and can be a 25% ethanol-water mixture. This inlet tube 12 is attached at one end to the extension 40 of the first passage 35 in the head assembly 2, or inserted here, see Figure 5. Fig. 5, and are permanently fluid-tightly connected to each other. A supply line for the operating fluid (not shown) can be connected to the outer nozzle 30 of the first passage 35. The other end of the inlet pipe 12 is located near the end piece 3 of the absorber, specifically inside the absorber. The end section of the coil located in this end section of the absorber is fluidly connected to this end of the inlet pipe 12. Thus, the operating fluid can be guided through the first passage 35 and the inlet pipe 12 to the end of the absorber sealed by the end piece 3. At this end of the inlet pipe 12, the operating fluid enters the coil of the heat exchanger 10. After the operating fluid has flowed through the coil, it can flow out of the heat exchanger 10 at the other end of the coil through the second passage 36 in the transverse wall 31.

[0021] The heat exchanger 10 also includes a storage device. This storage device comprises a tubular lance 15, which is located inside the module base body 1. Fig. 1) One of the end parts of this lance 15 is on the extension 40 of the fourth passage 38 in the head arrangement 2 - see Fig.3 - attached to or inserted into this and permanently fluid-tight connected to each other. The lance 15 extends from the head assembly 2 to near the end piece 3. The liquid storage medium is guided through this lance 15 to near the end piece 3. This liquid can move from the end piece 3 towards the head assembly 2 and thus fill the interior of an absorber housing, which is enclosed tank-like – like a reservoir – by the module base body 1, the head assembly 2 and the end piece 3. The storage medium can flow out of the absorber housing through the third passage 37 and through the opening 32 in the transverse wall 31 of the head assembly 2. The storage medium can be connected via the third passage 37 and fourth passage 38 to a separate tank container, which is designed as an open, unpressurized tank or as a closed tank with pressure equalization.

[0022] As an interactive storage medium, water can be filled with an additive that lowers the freezing point of water. This additive can be antifreeze or table salt. Advantageously, the antifreeze can be biodegradable and not hazardous to groundwater and / or made from renewable resources – such as sugar derivatives or ethanol.

[0023] The present geothermal heat absorber can also be designed as a prefabricated module for geothermal heat absorption. Such a module can have a length between 2.8 and 5.8 meters.

[0024] The close connection between the module base body 1 and the helix can be achieved through a suitable manufacturing process for the helix. A tube is wound onto a cylindrical jig (not shown) and treated so that it permanently assumes the shape of a helix. The outer diameter of the helix thus formed corresponds approximately to the diameter of the inner surface of the module base body 1 or is slightly larger. The helix is ​​stretched so that its outer diameter becomes smaller than the inner diameter of the module base body 1. In this stretched state, the helix is ​​inserted into the module base body 1, after which the helix is ​​released from the stretching force.

[0025] An alternative manufacturing process has proven particularly effective for geothermal absorber modules with a length exceeding 2 m and a pipe length of more than 55 m up to approximately 80 m for the helix. In this process, a pipe is wound onto a cylindrical jig and treated to permanently assume the shape of a helix. A prestress created by the deformation of the pipe is partially retained within the helix, which is wound with an outer diameter smaller than the inner diameter of the module base body 1. The helix, in this prestressed state, is inserted into the module base body 1 and then released from the prestress. During this process, the helix increases in outer diameter and conforms to an inner surface of the module base body 1.

[0026] The inlet pipe 12 is then connected to one end of the helix, and the module base 1 is closed with the end piece 3. The other end of the inlet pipe 12 and the other end of the helix are each connected to a passage of the head assembly 2. Reference symbol list 1 module base body 2 Head arrangement 3. Final piece 4 Klöpperboden wall 5 seam 6 dished heads 10 heat exchangers 12 Inlet pipe 15 lance 21 Ring wall 22 Edge section 23 ring-shaped edge section 24 first indentation 25 second indentation 26 first thigh 27 second thigh 28 Bridge 30 stubs 31 Cross wall 32 Opening 34 Wall section 35 first passage 36 second passage 37 third passage 38 fourth passage 39 tubular section 40 extension E-axis

Claims

[1] Ground source heat absorber with a cylindrical base body, characterized by , that the geothermal heat absorber is a prefabricated module for geothermal heat absorption, that a fluid-operated heat exchanger (10) is housed within the module body (1), and that the module has a head arrangement (2) by means of which the heat exchanger (10) of the module can be connected to a heat consumer. [2] Ground source heat absorber according to claim 1, characterized by , that the head arrangement (2) is located in the area of ​​at least one end part of the module base body (1), that this head arrangement (2) has a transverse wall (31), and that this transverse wall (31) carries at least one tubular passage (35, 36, 37, 38) which allows the passage of a liquid through the transverse wall (31). [3] Ground source heat absorber according to claim 1 or 2, characterized by, that the head arrangement (2) comprises at least one ring wall (21) which has the form of a wide ring, that this ring lies on an axis (E) common with the cylindrical module base body (1) and that this wide ring protrudes from the module base body (1). [4] Ground source heat absorber according to claim 3, characterized by , that an edge part (22) of the annular ring wall (21) is firmly connected to the cylindrical module base body (1), and that an annular edge part (23) of the ring wall (21) facing away from the module base body (1) is provided with a recess (24,25). [5] Ground source heat absorber according to claim 1, characterized by, that the heat exchanger (10) comprises a helix located inside the module base body (1), that an outwardly facing part of the helix of the heat exchanger (10) rests on an inner surface of the cylindrical module base body (1) with preload, and that each end of the heat exchanger (10) is fluidly connected to an internal tubular section (39) of one of the passages (35, 36). [6] Ground source heat absorber according to claim 1 or 5, characterized by , that the heat exchanger (10) is filled with an operating fluid. [7] Ground source heat absorber according to any one of claims 1 to 5, characterized by, that a storage device is arranged inside the fluid-tight module base body (1), that this storage device comprises a tubular lance (15), that an end piece of the lance (15) is fluidly connected to the inner tubular section (39) of another of the tubular passages (35, 36, 37, 38) in the head arrangement (2), that the lance (15) extends to the area of ​​the opposite end part of the cylindrical module base body (1), that the storage device comprises an opening (32) in the transverse wall (31) through which a storage medium, which contacts the majority of the heat exchanger (10), can leave an interior enclosed by the cylindrical module base body (1), and that the storage device may also include an interactive storage medium. [8] Ground source heat absorber according to claim 7, characterized bythat the interactive storage medium contains water and the water includes an additive that serves to lower the freezing point of water, whereby this additive may be an antifreeze or table salt. [9] Ground source heat absorber according to claim 2, characterized by , that both the end piece (3) and the transverse wall (31) are designed as a dished end (6). [10] Ground source heat absorber according to any of the preceding claims, characterized by that several of the modules are connected together, that the modules are connected in parallel and / or in series, and that arrangements consisting of such modules can be arranged horizontally, vertically, or at an angle.

Images