Heat Exchanger And Heat Management System Having Such A Heat Exchanger

Abstract

A heat exchanger for heat transfer between a heat exchange medium and a surrounding liquid has first and second main lines. The first main line defines a main through-flow cross section. A heat exchanger section carries a heat exchange medium and its through-flow cross section in larger than the main through-flow cross section. The heat exchanger section is connected at a first end to the first main line and at a second end to the second main line such that the heat exchange medium is distributed hydraulically symmetrically between the first main line and the heat exchanger section and between the second main line and the heat exchanger section. A heat management system has a heat circuit, a hollow, liquid-filled pile let into the ground, and one or more heat exchangers in the hollow pile.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the priority, under 35 U.S.C. .sctn.119, of German patent application DE 10 2013 001 995.8, filed Feb. 6, 2013; the prior application is herewith incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

[0002] The invention relates to a heat exchanger for the transfer of heat between a heat exchange medium and a surrounding liquid. Furthermore, the invention relates to a heat management system which has a heat exchanger of this type.

[0003] Refrigerating machines are conventionally used for supplying cooling circuits for machines. The refrigerating machines cool the heat exchange medium (usually water), which flows in the cooling circuit, to a desired temperature. One disadvantage of the refrigerating machines, however, is their high energy consumption.

[0004] As an energy-saving alternative, the cooling circuits are partially also cooled in cooling towers via fluid/air heat exchangers or in direct contact of the fluid with the air. A limiting factor here for the cooling circuit temperature which can be achieved is the ambient temperature which is frequently subject to high fluctuations throughout the year and/or according to the time of day.

[0005] As an alternative, the cooling circuits are also cooled in cold liquids, such as groundwater or river water which is stored, for example, in pools or tanks. For this purpose, different forms of heat exchangers are known. Typically, tubular heat exchangers are frequently used which guide the heat exchange medium through tube bundles which are bent in a U-shape, and which dip into the liquid of a tank of this type.

SUMMARY OF THE INVENTION

[0006] It is accordingly an object of the invention to provide a heat exchanger and an associated management system which overcome a variety of disadvantages of the heretofore-known devices and methods of this general type and which provides for a heat exchanger that is of simple construction but is nevertheless efficient. It is a further object of the invention to provide for a heat management system which is of simple construction and is efficient.

[0007] With the foregoing and other objects in view there is provided, in accordance with the invention, a heat exchanger for heat transfer between a heat exchange medium and a surrounding liquid, the heat exchanger comprising:

[0008] a first main line having a main through-flow cross section;

[0009] a second main line;

[0010] a heat exchanger section for conducting the heat exchange medium therethrough, the heat exchanger section having a heat exchanger through-flow cross section greater than the main through-flow cross section;

[0011] the heat exchanger section having a first end connected to the first main line and a second end connected to the second main line to cause the heat exchange medium to be distributed substantially hydraulically symmetrically between the first main line and the heat exchanger section and between the second main line and the heat exchanger section.

[0012] With the above and other objects in view there is also provided, in accordance with the invention, a heat management system that comprises:

[0013] a heat circuit for a heat exchange medium;

[0014] at least one hollow pile filled with a liquid and let into the ground, the hollow pile having a substantially greater length in comparison with a width thereof, and being oriented with a longitudinal direction thereof substantially perpendicularly with respect to the ground surface;

[0015] at least one heat exchanger as summarized above and described herein; the heat exchanger is disposed with the first end of the heat exchanger section close to the ground surface in the hollow pile, and connected by way of the first and second main lines to the heat circuit, and conducting the heat exchange medium therethrough in order to transfer heat between the liquid and the heat circuit.

[0016] In other words, the heat exchanger according to the invention is provided for the transfer of heat between a heat exchange medium and a surrounding liquid. According to the invention, the heat exchanger comprises a first main line and a second main line in order to guide the heat exchange medium. Here, the through-flow cross section of the first main line is called the main through-flow cross section. Furthermore, the heat exchanger comprises a heat exchanger section, through which the heat exchange medium can flow. Here, the heat exchanger section has a through-flow cross section which is called the heat exchanger through-flow cross section, said heat exchanger through-flow cross section being enlarged in comparison with the main through-flow cross section. Moreover, the heat exchanger section is connected at a first end to the first main line and at a second end to the second main line in such a way that the heat exchange medium is divided substantially, that is to say approximately, hydraulically symmetrically between the first main line and the heat exchanger section and between the second main line and the heat exchanger section.

[0017] The term "hydraulically symmetrical distribution" is understood here and in the following text to mean that the heat exchange medium is transferred from the first and the second main line to the heat exchanger section in such a way that the heat exchange medium flows in every part cross section of the heat exchanger through-flow cross section, apart from boundary effects, constantly at an approximately identical flow speed. This (virtually) homogeneous through-flow of the heat exchanger through-flow cross section advantageously leads in the heat exchanger section to a uniform transfer of heat between the heat exchange medium and the surroundings or the liquid.

[0018] Moreover, the heat exchanger through-flow cross section which is enlarged in comparison with the main through-flow cross section advantageously achieves a situation where the heat exchange medium has a slower flow speed when flowing through the heat exchanger section in comparison with the flow through the first main line. This has the advantage that a particularly long dwell time in the heat exchanger section is available to the heat exchange medium, which particularly long dwell time results in an improved exchange of heat. To this end, the heat exchanger through-flow cross section is preferably considerably greater than the main through-flow cross section, for example at least twice as great.

[0019] The heat exchanger section is preferably manufactured from stainless steel. In the context of the invention, however, the heat exchanger section can also be manufactured from aluminum or plastic with an optimized thermal conductivity.

[0020] In one preferred embodiment, the through-flow cross section of the second main line corresponds to the main through-flow cross section, that is to say the through-flow cross section of the first main line. This has the advantage that the flow speed of the heat exchange medium is identical in the first and in the second main line.

[0021] In one particularly preferred embodiment, the heat exchanger section has an elongate shape in the flow direction of the heat exchange medium. The heat exchanger section is preferably of considerably longer configuration here than the greatest extent, perpendicular with respect to the flow direction, of the cross-sectional area of the heat-exchanger section, through which cross-sectional area the heat exchange medium flows. For example, the length is at least three times said extent. In particular, the heat exchanger section has a length of at least 4 m. The heat transfer section, formed by the heat exchanger section, for the heat exchange medium is therefore particularly large, with the result that a particularly long time for the transfer of heat to the surroundings or the surrounding liquid is available to the heat exchange medium during the through-flow of the heat exchanger section.

[0022] In the context of the invention, it is conceivable in principle that the heat exchanger section is formed from a flat tube with a rectangular through-flow cross section or by way of a plurality of tubes which are arranged next to one another in one line. In one expedient embodiment, the heat exchanger section has a hollow cylindrical geometry, however. This is understood to mean that the heat exchange medium within the heat exchanger section is guided along a cylinder shell face at a spacing from a central axis of the heat exchanger section. In other words, the heat exchanger through-flow cross section lies completely between two concentric cylinder shell faces. As a result, the heat exchanger section has at least one contact area (or one contact area section) which is directed with its surface perpendicular to the outside from the hollow cylindrical geometry, and at least one further contact area (or one further contact area section) which is directed with its surface perpendicular toward the inner side of the hollow cylindrical geometry. The heat exchange medium which flows in the heat exchanger section is therefore surrounded both on the outside and on the inside by the surrounding liquid.

[0023] In one possible embodiment of the invention, the heat exchanger section has a single flow channel which is formed by a hollow cylindrical slot as viewed in cross section. In other words, the heat exchanger section in this embodiment corresponds to a double-walled tube, the inner and outer tube walls of which form a hollow cylinder. Each of the tube walls therefore also forms an outwardly and inwardly, respectively, directed contact area of the heat exchanger section. In this case, the heat exchange medium flows in the hollow cylindrical slot, that is to say between the inner and the outer tube wall. On account of the symmetrical distribution of the heat exchange medium to the heat exchanger section, the heat exchange medium flows over the entire annular cross-sectional area of the hollow cylindrical slot (at least at a sufficient spacing from the opening points at the upper and lower end of the heat exchanger section) approximately at a homogeneous (that is to say, constant in the circumferential direction) flow speed.

[0024] In one preferred embodiment, however, the heat exchanger section has a plurality of flow channels which are arranged distributed symmetrically with respect to one another around the cylinder shell of the hollow cylindrical geometry. Here, the flow channels are, in particular, of elongate, that is to say rectilinear, configuration between the first and the second end of the heat exchanger section and run in an axially parallel manner. In the context of the invention, however, the flow channels can also in principle be set toward the axis of the hollow cylindrical heat exchanger section, in particular can run in a helical manner. Here, each of said flow channels forms, with its through-flow cross section, in each case one of the part cross sections of the heat exchanger through-flow cross section, in which the heat exchange medium flows at an identical flow speed.

[0025] In the context of the invention, it is conceivable here to form the heat exchanger section from two tubes which are made from corrugated metal and are arranged coaxially with respect to one another, the corrugation peaks and corrugation troughs of the two tubes running in the longitudinal direction of the heat exchanger section. Here, the two "corrugated metal tubes" are dimensioned in such a way that in each case one corrugation peak of the inner tube is in contact with one corrugation trough of the outer tube and is preferably connected to the latter at this point. As a result, each corrugation trough of the inner tube forms one of the flow channels with the corrugation peak of the outer tube.

[0026] In a preferable manner and in an embodiment which is expedient in terms of manufacturing technology, however, the flow channels are formed by in each case one single tube which runs in the longitudinal direction of the heat exchanger section. Here, the tubes are expediently fixed parallel to one another over the length of the heat exchanger section by at least one spacer element. The spacer element is formed, for example, by a plate or a ring, on which the tubes are secured or through which the tubes are guided.

[0027] On account of the elongate, rectilinear shape of the heat exchanger section and, in particular, of its flow channels, it is made possible in a simple way to advantageously utilize a temperature gradient of the surrounding liquid. Here, in an analogous manner to the principle of counter flow cooling, the heat exchange medium is preferably guided through the heat exchanger section in such a way that the temperature gradient which forms of the heat exchange medium is directed identically to the temperature gradient of the surrounding liquid.

[0028] In one expedient embodiment, the heat exchanger section, and, in particular, its flow channels, are connected at the first and second end centrally to the first main line and to the second main line. Here, the first and the second main line are arranged, in particular, on a center axis or axis of symmetry of the hollow cylindrical geometry of the heat exchanger section and, from there, are connected to the heat exchanger section via in each case identically long connecting channels which are called distributor channels and in each case have the same through-flow cross section.

[0029] In one preferred embodiment, the first and the second main line are coupled via in each case one distributor to the heat exchanger section in a star-shaped manner. In other words, the distributor channels extend in the shape of radial beams from the respective (central) main line in the direction of the or each flow channel. In one simple embodiment, the distributor is a plate, the base area of which corresponds to the cross-sectional area of the heat exchanger section. The first and the second main line are attached to said plate perpendicularly, that is to say in the normal direction of the (distributor) plate and are connected to the distributor channels. Here, the distributor channels are made in the plate, for example as bores, in particular perpendicularly with respect to the respective main line, that is to say in the plate plane, and open into the respective flow channel once again perpendicularly with respect to the plate plane.

[0030] As an alternative, the (distributor) plate is reduced in size in comparison with the cross-sectional area of the heat exchanger section. Here, the respective distributor channels are extended by way of distributor tubes and are guided out of the plate. Here, the flow channels are attached via in each case one angled part to the distributor tubes. The distributor plate is manufactured, for example, from aluminum.

[0031] In a further alternative embodiment, the distributor is configured as a spoked wheel. Here, the distributor channels are guided from the respective main line in the form of tubes radially to the outside to an annular disk, within which the respective distributor channel is deflected in the flow direction of the flow channels. Here, said annular disk expediently additionally serves as a spacer piece between the distributor channels and optionally between the tubes which form the flow channels.

[0032] In one preferred and space-saving embodiment, the second main line is guided in the direction of the first end of the heat exchanger section within the area which is enclosed by the heat exchanger section. Here, in particular, the second main line is guided out of the heat exchanger section between the distributor channels of the distributor in the region of the first end of the heat exchanger section.

[0033] In one expedient embodiment, the second main line is insulated thermally with respect to the surroundings or the liquid which surrounds the heat exchanger. This effectively prevents that an interaction of the heat exchange medium which flows in the second main line takes place with the surroundings or the surrounding liquid. As a result, for example, the cooled heat exchange medium can be returned in the liquid, without the heat exchange medium heating up again in the region of higher liquid temperatures.

[0034] In the context of the invention, it is conceivable in principle that the flow direction of the heat exchange medium and therefore the heat exchanger section itself are oriented substantially horizontally in the operating state. In this embodiment, the heat exchanger can be arranged, for example in order to cool the heat exchange medium, in a river or in a comparable (flat and horizontally oriented) heat sink. However, the heat exchanger is preferably used in such a way that the flow direction and therefore the heat exchanger section are oriented substantially, that is to say exactly or approximately, vertically. In this embodiment, the heat exchanger is provided, in particular, for use in a bore hole which is filled with liquid, for example a well, a cistern or preferably in an energy pile which is made in the ground. "Energy pile" is understood to mean a solid pile or a hollow pile which is filled with liquid and is equipped with a heat exchanger.

[0035] The heat management system according to the invention comprises a heat circuit for a heat exchange medium and at least one hollow pile which is filled with liquid. Here, the hollow pile is let into the ground and has a substantially greater length in comparison with its width. In addition, the hollow pile is oriented with its longitudinal direction substantially, that is to say exactly or approximately, perpendicularly with respect to the ground surface. Moreover, the heat management system comprises a heat exchanger of the type described at the outset, which heat exchanger is arranged with the first end of its heat exchanger section close to the ground surface in the hollow pile. That is to say, the heat exchanger section is arranged with its first end in the region of an upper end of the hollow pile, the second end of the heat exchanger section preferably being arranged in the hollow pile such that it is distant from the ground surface, that is to say deeper than the first end. Here, the heat exchanger section preferably reaches with its second end as far as or at least virtually as far as the lower end of the hollow pile. The heat exchanger is connected by means of its first and second main line to the heat circuit and can be flowed through by the heat exchange medium for the transfer of heat between the liquid and the heat circuit.

[0036] The liquid, with which the hollow pile is filled, advantageously makes a particularly effective transfer of heat between the heat exchange medium and the liquid possible by way of heat-induced circulation around the heat exchanger section. Furthermore, the liquid also makes an efficient transfer of heat possible between the ground which surrounds the hollow pile and the liquid itself. On account of the pronounced longitudinal extent and the perpendicular installed position of the hollow pile, an advantageous temperature stratification is additionally produced within the liquid in the hollow pile during operation of the heat management system. As a consequence of said temperature stratification, greatly different temperature levels within the liquid are formed at both longitudinal ends of the hollow pile, that is to say in the region of the upper and lower end. One advantageous effect of said temperature stratification consists here in that the low and high temperature levels at the lower and upper end of the hollow pile remain largely constant even in the case of an input of heat into the hollow pile via the heat exchanger, since a virtually mixing-free exchange of heated liquid volumes with cold liquid takes place within the hollow pile. The same applies to the removal of heat from the hollow pile.

[0037] In one preferred embodiment, the hollow pile has a length of at least 5 m, in particular a length of between 20 m and 40 m. A length of this type assists the formation of the temperature stratification and the associated temperature stability. In particular, on account of the great length of the hollow pile and the corresponding installation depth into the ground, the temperature stratification is already produced inherently by way of the exchange of heat of the liquid in the hollow pile with the surrounding ground, which leads to an equalization of the local liquid temperature to the natural temperature profile of the ground.

[0038] It is utilized here for cooling purposes that the ground as a rule has an at least approximately constant temperature which is therefore independent of the season below a depth of approximately 10 m. This temperature is typically approximately 8.degree. C. in moderate climate zones. Here, the exchange of heat with the surrounding ground extends the capacity of the hollow pile to store heat output by the liquid and makes rapid energetic regeneration of the hollow pile possible after an extensive input of heat or removal of heat.

[0039] In one preferred embodiment, the hollow pile is formed, in particular, by a reinforced concrete pipe which is closed in a liquid-tight manner at the intended lower end and which is closed by way of a cover at its upper end in the installed state.

[0040] In one expedient embodiment, the length of the heat exchanger section corresponds approximately to the length of the hollow pile or undershoots the latter slightly, with the result that the heat exchanger section can be arranged completely within the hollow pile.

[0041] On account of the stable temperature stratification in the hollow pile, it is possible, moreover, to use the hollow pile both as a heat sink for cooling purposes and as a heat source for heating. For this purpose, the first main line of the heat exchanger can be used as feed line or return line. Here, the heat exchanger is operated for cooling the heat exchange medium in such a way that the heat exchange medium is introduced via the first main line into the heat exchanger section and is guided back via the second main line at the second end of the heat exchanger section. The heat exchange medium therefore flows through the liquid column of the hollow pile from top to bottom and is cooled increasingly in the process on account of the above-described temperature stratification in the hollow pile as a result of the decreasing temperature of the liquid in the hollow pile. Here, as high an equalization as possible of the temperature of the heat exchange medium to the respective temperature level of the liquid in the hollow pile is achieved by way of suitable dimensioning of the heat exchanger through-flow cross section and the particularly slow flow speed of the heat exchange medium which is achieved as a result. When the second end of the heat exchanger section is reached, the heat exchange medium is fed via the distributor to the second main line and is guided back to the heat circuit. On account of the optionally present thermal insulation of the second main line, the heat exchange medium cannot warm up again in the region of the warmer temperature layers when flowing through the hollow pile from the bottom to the top.

[0042] For the reverse case, namely that the heat exchange medium is to be warmed up in comparison with the temperature which is present in the heat circuit, in one expedient embodiment the comparatively cold heat exchange medium is guided via the (optionally thermally insulated) second main line into the lower end of the hollow pile and is guided there into the second end of the heat exchanger section. From there, the heat exchange medium rises in the flow channel or flow channels in the direction of the first end of the heat exchanger section and is heated in the process via the transfer of heat from the increasingly warm liquid layers in the hollow pile. When the first end of the heat exchanger section is reached, the heat exchange medium which is then heated is guided via the first main line back into the heat circuit. In the context of the invention, the first main line can additionally likewise be thermally insulated.

[0043] The first heat circuit and the heat exchanger which is connected to it preferably form a closed system. For example, a heat source or a heat sink which is assigned to a consumer, in particular a machine which is to be cooled or temperature-controlled or, as an alternative, a building heating or cooling system, can be connected to said closed system.

[0044] In a further embodiment of the heat management system, a plurality of the above-described heat exchangers are arranged next to one another in the hollow pile. Depending on the cross-sectional profile of the hollow pile (polygonal or circular), the heat exchangers are arranged here in a lattice-shaped or in a circular structure in the hollow pile. In one embodiment which is expedient in terms of manufacturing technology, the hollow pile has, in particular, a circular cross-sectional profile. In this case, the heat exchangers are preferably arranged in the hollow pile in a comparable manner to rounds in a cylinder of a revolver. Here, in the context of the invention, one of the heat exchangers can also be arranged on the "rotational axis of the cylinder," that is to say the center axis of the hollow pile.

[0045] Other features which are considered as characteristic for the invention are set forth in the appended claims.

[0046] Although the invention is illustrated and described herein as embodied in a heat exchanger and heat management system having a heat exchanger of this type, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

[0047] The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0048] FIG. 1 shows a diagrammatic side view of a heat exchanger;

[0049] FIG. 2 shows an enlarged illustration with interruptions of the heat exchanger according to FIG. 1;

[0050] FIG. 3 shows the heat exchanger according to FIG. 1 in a section III-III according to FIG. 2;

[0051] FIG. 4 shows the heat exchanger according to FIG. 1 in a section IV-IV according to FIG. 2;

[0052] FIG. 5 shows a diagrammatic side view of a heat management system having a hollow pile which is arranged in the ground and a heat exchanger according to FIG. 1 which is arranged in said hollow pile;

[0053] FIG. 6 shows an alternative exemplary embodiment of the heat exchanger in a view according to FIG. 2;

[0054] FIG. 7 shows the heat exchanger according to FIG. 6 in a section VII-VII;

[0055] FIGS. 8 and 9 show two further alternative exemplary embodiments of the heat exchanger in an illustration according to FIG. 7; and

[0056] FIG. 10 shows the heat exchanger according to FIG. 9 in a view according to FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

[0057] Referring now to the figures of the drawing in detail and first, particularly, to FIGS. 1 and 2 thereof, there is shown a heat exchanger 1 which is provided for the transfer of heat between a heat exchange medium and a liquid 2 which surrounds the heat exchanger. The heat exchanger 1 comprises a first main line 3 and a second main line 4. Furthermore, the heat exchanger 1 comprises a heat exchanger section 5, through which the heat exchange medium can flow. The heat exchanger section 5 is connected at a first end 6 to the first main line 3 and at a second end 8 which lies opposite the first end 6 in the longitudinal direction 7 to the second main line 4.

[0058] Here, the first main line 3 has a main through-flow cross section D. While the delimiting arrows in the figures point to the outer diameter of the pipes, it will be understood that the diameter is the inner diameter and the corresponding cross-section D is the inner cross-section, the area that is open to the flow. Here, the through-flow cross section of the second main line 4 corresponds to the main through-flow cross section D. The heat exchanger section 5 is formed from eight tubes 9 which in each case form a flow channel for the heat exchange medium and run rectilinearly in the longitudinal direction 7 between the first end 6 and the second end 8 of the heat exchanger section 5. Here, the flow direction of the tubes 9 corresponds to the longitudinal direction 7. Moreover, the individual tube cross sections D.sub.R are dimensioned in such a way that the sum of all tube cross sections D.sub.R exceeds the main through-flow cross section D of the first and second main line 3, 4 considerably, for example by two times. As a result, the flow speed of the heat exchange medium in the heat exchanger section 5 is reduced in comparison with the main lines 3, 4.

[0059] At the first end 6 of the heat exchanger section 5, its tubes 9 are connected via a distributor, called the first distributor plate 10, or head plate 10, in the following text, to the first main line 3. At the second end 8, the tubes 9 are connected via a second distributor plate 11, or foot plate 11, to the second main line 4. As can be seen from FIGS. 3 and 4, the eight tubes 9 are arranged here in a circular ring shape on the distributor plates 10 and 11, with the result that the heat exchanger section 5 has a hollow cylindrical geometry. That is to say, the heat exchanger section 5 borders a virtually circular area section with its tubes 9.

[0060] The first main line 3 is placed onto the distributor plate 10 centrally with respect to the tubes 9 that is to say on a center axis of said (circular) distributor plate 10. The tubes 9 are connected to the first main line 3 via in each case equally long distributor channels 12 which have the same cross section and are made in each case as a bore radially in the distributor plate 10. Furthermore, the tubes 9 protrude perpendicularly in the longitudinal direction 7 from that side of the distributor plate 10 which lies opposite the first main line 3. The second main line 4 is connected in a corresponding way via the connecting plate 11 to the tubes 9 (see FIG. 4). In contrast to the first connecting plate 10, however, the second main line 4 is guided out of the connecting plate 11 on the same side as the tubes 9. As can also be seen from FIGS. 1 and 2, the second main line 4 is thus guided from the second end 8 in the direction of the first end 6 in the area section which is bordered by the tubes 9, that is to say within the heat exchanger section 5. Here, the second main line is guided through the first distributor plate 10 in the region of the first end 6 between the distributor channels 12 (see FIGS. 1 to 3).

[0061] The distribution of the heat exchange medium between the first or the second main line 3 or 4 and the tubes 9 takes place in a hydraulically symmetrical manner via the distributor plates 10 or 11, insofar as the heat exchange medium in each of the tubes 9 flows under the same flow conditions, that is to say with an identical flow speed, on account of the distributor channels 12 which are in each case homogeneous.

[0062] As can be seen from FIGS. 1 to 4, the second main line 4 is insulated thermally with respect to the liquid 2 by an insulating jacket 14.

[0063] The heat exchanger section 5 has a length L which is considerably greater than the width of the through-flow cross section of the heat exchanger section 5, that is to say greater than the sum of the tube cross sections DR. The length L of the heat exchanger section 5 is additionally also considerably greater than the (overall) diameter of the hollow cylindrical heat exchanger section 5. Here, the length L of the heat exchanger section 5 is at least 4 m, in an expedient dimensioning between 20 m and 40 m. In order to stabilize the tubes 9 and their parallel arrangement over the length L, the heat exchanger section 5 has two spacer elements 16 between the first end 6 and the second end 8. The spacer elements 16 are configured as plates, through which the tubes 9 and the second main line 4 are guided (shown by dashed lines, see FIG. 2).

[0064] FIG. 5 shows the heat exchanger 1 in the case of use in a heat management system 18. Here, the heat management system 18 comprises a heat circuit (not shown in greater detail) which feeds the heat exchange medium via the first main line 3 or the second main line 4 into the heat exchanger 1 or the heat exchanger section 5 and removes it from the heat exchanger section 5. Furthermore, the heat management system 18 comprises a hollow pile 22 which is let perpendicularly into the ground 20 and is filled with the liquid 2. The heat exchanger 1 is arranged within the hollow pile 22 in such a way that the heat exchanger section 5 is surrounded completely by the liquid 2. The length L of the heat exchanger section 5 corresponds approximately to the length of the hollow pile 22, with the result that the first end 6 of the heat exchanger section 5 is arranged in the region of the upper end 24 of the hollow pile 22 and the second end 8 of the heat exchanger section 5 reaches as far as the lower end 26 of the hollow pile 22.

[0065] The hollow pile 22 is closed in a liquid-tight manner at its lower end 26 by way of a closure plate 28. In the intended installed state which is shown in FIG. 5, the upper end 24 of the hollow pile 22 is closed by way of a cover 30, the first and second main line 3, 4 of the heat exchanger 1 being guided through the cover 30. In order to make a particularly satisfactory transfer of heat to the soil 32 possible, the hollow pile 22 is pressed with a grouting compound 34 in the soil 32.

[0066] Depending on whether the heat exchange medium is to be cooled or to be heated via the heat exchanger 1, the first and the second main line 3, 4 can be used both as a feed line and as a return line. For the case where the heat exchange medium is to be cooled, it is introduced via the first main line 3 into the first end 6 of the heat exchanger section 5 and therefore flows in the direction of the lower end 26 of the hollow pile 22. The result of the perpendicular installation of the hollow pile 22 is a temperature stratification in the liquid 2 which becomes cooler from top to bottom. This leads to the heat exchange medium being cooled increasingly during the through-flow of the heat exchanger section 5 from top to bottom. After the converging of the heat exchange medium via the distributor plate 11 into the main line 4, the insulating jacket 14 prevents the heat exchange medium which rises in the direction of the upper end 24 being warmed in the second main line 4 by interaction with the liquid 2. For the case where a cool heat exchange medium is to be heated via the heat management system 18, the heat exchange medium is introduced via the second main line 4 at the lower (cool) end 26 of the hollow pile 22 into the heat exchanger section 5. During rising through the tubes 9 in the direction of the upper (warm) end 24 of the hollow pile 22, the heat exchange medium heats up and is removed via the distributor plate 10 and the first main line 3. The suitability of the first and second main lines 3 and 4 as feed line and return line is indicated by the flow direction arrows 36.

[0067] FIG. 6 and FIG. 7 show an alternative exemplary embodiment of the heat exchanger 1. Here, in contrast to the heat exchanger 1 which is shown in FIGS. 1 to 5, the distributor plates 10 and 11 in each case have a smaller diameter compared to the area section which is bordered by the tubes 9. The tubes 9 are connected via in each case one angled part 38 to the distributor channels 12 of the distributor plates 10 and 11. Here, the angled parts 38 are guided out of the distributor plates 10 and 11 perpendicularly with respect to the longitudinal direction 7 and in an extension of the respective distributor channel 12. The second main line 4 can be fixed on the first distributor plate 10 in a way which is not shown in greater detail, for example by way of a pipe clamp.

[0068] In an alternative exemplary embodiment of the heat exchanger 1 according to FIG. 8, the heat exchanger section 5 is formed by a single double-walled tube 40. Here, the heat exchange medium flows in an intermediate space (called a hollow cylindrical slot) between the outer tube wall 41 and the inner tube wall 42 of the double-walled tube 40. Here, the cross-sectional area of the hollow cylindrical slot is greater than the cross-sectional area or the main through-flow cross section D of the first and second main line 3, 4. This therefore likewise results, in the heat exchanger section 5, in the flow speed of the heat exchange medium which is slower than in the first and second main lines 3, 4.

[0069] In order to distribute the heat exchange medium from the first main line 3 to the double-walled tube 40, the first main line 3 is connected to the double-walled tube 40 in a star-shaped manner via eight distributor tubes 44. The attachment of the second main line 4 at the second end 8 of the heat exchanger section 5 or the double-walled tube 40 takes place in an analogous manner. In this exemplary embodiment, the distribution of the heat exchange medium to the heat exchanger section 5 also takes place in a hydraulically symmetrical manner, insofar as the heat exchange medium flows within the hollow cylindrical slot with a constant flow speed in the circumferential direction at a sufficient spacing from the opening points of the distributor tubes 44.

[0070] In a further alternative exemplary embodiment according to FIG. 9, the heat exchanger section 5 is formed by a double-walled tube, which is called a corrugated metal tube 46 in the following text. Here, the inner tube wall 42 is connected to the outer tube wall 41 at eight connecting points 48. This results in a total of eight flow channels 50 which run in the longitudinal direction 7 between in each case two connecting points 48, into which flow channels 50 the main lines 3 and 4 are coupled in a hydraulically symmetrical manner by means of the distributor tubes 44. The sum of the individual through-flow cross sections of the flow channels 50 once again exceeds the main through-flow cross section D of the first and second main line 3, 4.

[0071] As can be gathered from FIG. 10, apertures 52 are made in the corrugated metal tube 46 within the (elongate) connecting points 48. The apertures 52 serve, for example, to fasten the heat exchanger section 5 in the hollow pile 22 which is shown in FIG. 5 and/or to make an exchange of the liquid 2 possible between the inner side and the outer side of the hollow cylindrical geometry of the heat exchanger section 5.

[0072] The heat exchanger section 5, in particular the tubes 9, the double-walled tube 40 and the corrugated metal tube 46, are manufactured, for example, from stainless steel which is rust-proof and resistant to salt water. As an alternative, however, the heat exchanger section 5 can also be manufactured, for example, from comparatively resistant plastic having a high thermal conductivity. The distributor plates 10 and 11 and the spacer elements 16 are manufactured, for example, from aluminum which is resistant to salt water.

[0073] The subject matter of the invention is not restricted to the above-described exemplary embodiments. Rather, further embodiments of the invention can be derived from the above description by a person skilled in the art. In particular, the individual features of the invention which are described using the various exemplary embodiments and the design variants thereof can also be combined with one another in a different way.

[0074] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: [0075] 1 Heat exchanger [0076] 2 Liquid [0077] 3 First main line [0078] 4 Second main line [0079] 5 Heat exchanger section [0080] 6 First end [0081] 7 Longitudinal direction [0082] 8 Second end [0083] 9 Tube [0084] 10 Distributor plate [0085] 11 Distributor plate [0086] 12 Distributor channel [0087] 14 Insulating jacket [0088] 16 Spacer element [0089] 18 Heat management system [0090] 20 Ground [0091] 22 Hollow pile [0092] 24 Upper end [0093] 26 Lower end [0094] 28 Closure plate [0095] 30 Cover [0096] 32 Soil [0097] 34 Grouting compound [0098] 36 Flow direction arrow [0099] 38 Angled part [0100] 40 Tube [0101] 41 Outer tube wall [0102] 42 Inner tube wall [0103] 44 Distributor tube [0104] 46 Corrugated metal tube [0105] 48 Connecting point [0106] 50 Flow channel [0107] 52 Aperture [0108] D Main through-flow cross section (inner diameter) [0109] D.sub.R Tube cross section [0110] L Length

Claims

1. A heat exchanger for heat transfer between a heat exchange medium and a surrounding liquid, the heat exchanger comprising: a first main line having a main through-flow cross section; a second main line; a heat exchanger section for conducting the heat exchange medium therethrough, said heat exchanger section having a heat exchanger through-flow cross section greater than the main through-flow cross section; said heat exchanger section having a first end connected to said first main line and a second end connected to said second main line to cause the heat exchange medium to be distributed substantially hydraulically symmetrically between said first main line and said heat exchanger section and between said second main line and said heat exchanger section.

2. The heat exchanger according to claim 1, wherein said second main line has a through-flow cross section corresponding to the main through-flow cross section.

3. The heat exchanger according to claim 1, wherein said heat exchanger section has an elongate shape in a flow direction of the heat exchange medium.

4. The heat exchanger according to claim 1, wherein said heat exchanger section has a hollow cylindrical geometry.

5. The heat exchanger according to claim 4, wherein said heat exchanger section comprises a flow channel which is formed by a hollow cylindrical slot.

6. The heat exchanger according to claim 4, wherein said heat exchanger section is formed with a plurality of elongate flow channels that are arranged symmetrically with respect to one another along a cylinder shell face.

7. The heat exchanger according to claim 4, wherein said first end of said heat exchanger section is connected centrally to said first main line and said second end is connected centrally to said second main line.

8. The heat exchanger according to claim 7, which comprises a distributor coupling said first main line to said heat exchanger section and a distributor coupling said second main line in each case with a star-shaped coupling.

9. The heat exchanger according to claim 7, wherein said second main line is guided in a direction of said first end within an area enclosed by said heat exchanger section.

10. The heat exchanger according to claim 1, wherein said second main line is thermally insulated with respect to surroundings thereof.

11. The heat exchanger according to claim 1, wherein a flow direction of the heat exchange medium in said heat exchanger section is oriented substantially vertically.

12. A heat management system, comprising: a heat circuit for a heat exchange medium; at least one hollow pile filled with a liquid and let into the ground, said hollow pile having a substantially greater length in comparison with a width thereof, and being oriented with a longitudinal direction thereof substantially perpendicularly with respect to the ground surface; at least one heat exchanger according to claim 1, disposed with the first end of the heat exchanger section close to the ground surface in said hollow pile, and connected by way of said first and second main lines to said heat circuit, and conducting the heat exchange medium therethrough in order to transfer heat between the liquid and said heat circuit.

13. The heat management system according to claim 12, wherein said first main line is selectively usable as a feed line or as a return line.

14. The heat management system according to claim 13, wherein said at least one heat exchanger is one of a plurality of heat exchangers disposed next to one another in said hollow pile.