Heat storage system and heat exchanger for the heat storage system

Abstract

The invention relates to a heat reservoir (1) and a heat exchanger (7) therefor, having a first and second connection (8, 9), having a corrugated pipe (12) which is provided in the flow path (10) between the first and second connections (8, 9) and has a first pipe portion (13a) which is connected to the first connection (8), and a second pipe portion (13b) which adjoins said first pipe portion (13a) and extends helically. According to the invention, in order to ensure high pressure resistance, the heat exchanger (7) has a reinforcement (14) which is provided in the corrugated pipe (12), extends in the first pipe portion (13a) and ends in the second pipe portion (13b).

Description

Technical field

[0001] The invention relates to a heat storage device and a heat exchanger for this heat storage device with a first and second connection, with a corrugated pipe provided in the flow path between the first and second connection, which has a first pipe section connected to the first connection and a second pipe section adjoining this first pipe section, which runs in a helical shape. State of the art

[0002] To heat a heat transfer fluid in a thermal storage tank, it is known (EP2489945A2) to provide a flow channel within the tank containing a corrugated heat exchanger tube. The heat exchanger has two external connections on the tank, through which the corrugated tube can be supplied with a liquid medium. The corrugated tube within the tank has a first pipe section connected to the external connection. A second pipe section, located within the flow channel and running in a helical shape, connects to this first pipe section. The design of the second pipe section ensures high efficiency at the heat exchanger – due, among other things, to the turbulent flow created by the corrugated tube. A disadvantage of corrugated tubes is their tendency to expand longitudinally under increased fluid pressure, which impairs the tube's path within the flow channel and thus compromises the heat exchanger's efficiency.Furthermore, uncontrolled longitudinal expansion of the corrugated pipe can compromise the design, service life, and functionality of the heat storage system. EP 1 835 214 A1 discloses a heat storage system with a corrugated pipe according to the preamble of claim 1. The corrugated pipe is supported by externally mounted brackets. Description of the invention

[0003] The invention therefore aims to improve the stability of a heat storage device of the type described above in a structurally simple way with regard to higher media pressures at the heat exchanger, in order to make this heat storage device more versatile in its use.

[0004] The invention solves the stated problem through the features of claim 1.

[0005] By incorporating a stiffening element within the corrugated tube, extending through the first tube section and terminating in the second, the heat exchanger can withstand even higher pressures from media conveyed within it. This stiffening element ensures a defined path for the corrugated tube between the connection and the coil, preventing longitudinal expansion and thus instabilities. This significantly improves the pressure resistance of the heat exchanger. The heat exchanger according to the invention is therefore more versatile and, in particular, suitable for transferring media from a district heating network for heat exchange.

[0006] To further increase the pressure stability of the heat exchanger, the stiffening element can be designed to end after the second turn of the helix in the second pipe section. This stiffening element can also stabilize the shape of the corrugated pipe's helix. Due to the relatively high dimensional stability of the pipe helix, it may be sufficient, for example, if the stiffening element ends after the first turn of the helix in the second pipe section. It may even be sufficient if the stiffening element ends within the second turn of the helix.

[0007] The design of the heat exchanger can be simplified if the stiffening element is designed as an inner tube running inside the corrugated pipe. Furthermore, an inner tube is easy to handle in the first pipe section, which can further simplify the manufacturing of the heat storage unit.

[0008] If the first and / or second connection has a connector, and a fluid-tight press fit is provided between the connector and the corrugated pipe, this can further simplify the design.

[0009] This is particularly relevant when the corrugated pipe is positioned between the fitting and the stiffener, creating a press fit between the fitting, corrugated pipe, and stiffener. Furthermore, this ensures a particularly pressure-resistant transition between the fitting and the corrugated pipe, which can further increase the pressure stability of the heat exchanger.

[0010] Preferably, the stiffening in the pipe sections rests loosely against the corrugated pipe, which particularly stabilizes the pipe sections along their length and can thus further increase the stability of the heat exchanger.

[0011] If the corrugated pipe has a third pipe section connected to the second connection, and if the heat exchanger also has an additional stiffening element within the corrugated pipe that runs through the third pipe section and terminates in the second pipe section, a heat exchanger with excellent pressure resistance along its entire length can be created.

[0012] The heat exchanger according to the invention may be particularly suitable for use in a heat storage system with a container for holding a heat transfer medium.

[0013] The connections of the heat exchanger can form external connections on the heat storage tank or be connected to external connections of the heat storage tank.

[0014] The heat exchanger according to the invention can be particularly advantageous in a heat storage device which has a flow channel provided in the container, which is designed to form free convection of the heat transfer medium, wherein the second pipe section is located in the flow channel.

[0015] The efficiency of the heat exchanger can be increased if the flow channel in the area of ​​the second pipe section is designed to run vertically in one direction.

[0016] If the wall of the flow channel has thermal insulation, this can further increase the efficiency of the heat exchanger. Brief description of the drawing

[0017] The figures illustrate, for example, the invention in more detail using one embodiment as an example. They show Fig. 1 a sectional view of a heat storage unit with a heat exchanger and Fig. 2 an enlarged partial view of the heat exchanger of the after Fig. 1 depicted heat storage system. Method for implementing the invention

[0018] The after Fig. 1 The heat storage unit 1, as illustrated, has a container 2 which is enclosed by a container wall 3. An external insulation is attached to this container wall 3.

[0019] The heat transfer medium 4 of the heat-charged container 2 has a vertical temperature gradient that can be used for free convection 5. For this purpose, a flow channel 6 is provided in the heat storage container 1.

[0020] The heat storage unit 1 is charged or discharged via an indirect heat exchanger 7. This heat exchanger 7 has a first connection 8 and a second connection 9, between which connections 8, 9 a flow path 10 for a liquid medium 11 is formed.

[0021] The connections 8, 9 of the heat exchanger 7 are provided in the heat storage tank 1 and connected to the external connections 80, 90 of the heat storage tank 1 via connecting lines 81, 91. However, it is also conceivable that the connections 8, 9 of the heat exchanger on the heat storage tank 1 form external connections 80, 90 – which is not shown.

[0022] Furthermore, the heat exchanger 7 includes a corrugated pipe 12, namely a spiral corrugated pipe – preferably made of stainless steel. The corrugated pipe 12 runs inside the container 2 and is connected to the two ports 8 and 9.

[0023] The corrugated pipe 12 has several pipe sections 13a, 13b, 13c. The first pipe section 13a connects to the first connection 8. The third pipe section 13c connects to the second connection 9. The first and third pipe sections 13a, 13c each connect to the second pipe section 13b, which second pipe section 13b is provided in the flow channel 6 – as shown in Fig. 1 to recognize.

[0024] The second pipe section 13b also has a helical shape. As is known, this, in conjunction with the corrugated pipe shape, allows turbulent flow to be generated in the flow channel 6, resulting in high efficiency at the heat exchanger 7.

[0025] To eliminate the known disadvantage of a corrugated pipe 12 with regard to low pressure resistance in the longitudinal direction, the heat exchanger 7 has a stiffening element 14. This stiffening element 14 runs along the entire first pipe section 13a and ends in the second pipe section 13b with a stiffening end 14b, in particular a blunt one. Fig. 2 to be seen in detail.

[0026] This prevents the corrugated pipe 12 from deflecting laterally even under higher internal pressure of the liquid medium 11, thus preventing longitudinal expansion of the corrugated pipe 12. This makes the heat exchanger 7 more resistant to high hydraulic pressure, expanding the possible uses of the heat storage unit 1 and the heat exchanger 7 – for example, also for connection to a district heating network (not shown).

[0027] Again Fig. 2 This stiffening element 14, which can be removed, ends after the first turn 15a of the helix 15 of the second pipe section 13b. Thus, the corrugated pipe 12 is fixed along its path until the helix becomes self-stabilizing. This ensures high pressure resistance of the heat exchanger 7, as the stiffening element absorbs, among other things, an axial load on the corrugated pipe 12. The corrugated pipe 12 is therefore particularly resistant to axial, tensile, and / or compressive stresses.

[0028] However, it is also conceivable that this stiffening 14 ends after a second turn 15b of the helix 15 of the second pipe section 13b - which is not shown.

[0029] How also the Fig. 2 As can be seen, the stiffening 14 is designed as an inner tube 14a, preferably smooth on the outside and / or inside.

[0030] This stiffening element 14 runs with the corrugated tube 12 into a connecting piece 16 of the first connection 8, as shown in Fig. 2 to be recognized. A fluid-tight press fit 17 is provided between the connecting piece 16, the corrugated pipe 12 and the stiffening 14 in order to ensure a pressure-resistant hydraulic transition into the corrugated pipe 12 at the heat exchanger 7.

[0031] Furthermore, the stiffening element 14 rests loosely against the corrugated pipe 12 in pipe sections 13a and 13b at most – which is in the Fig. 2 This is evident. This allows a certain degree of flexibility in the corrugated pipe 12, for example to compensate for pressure fluctuations in the liquid medium 11, but the course of the corrugated pipe 12 remains fixed in these sections. The second helically shaped pipe section 13b is therefore provided with a stiffener 14 at both ends. This ensures high dimensional and pressure stability.

[0032] The same structure is also provided at the second connection 9 of the heat exchanger, from which the corrugated pipe 12 has a third pipe section 13c.

[0033] Here too, a stiffening element 14 is provided in the corrugated pipe 12, which runs in the third pipe section 13c and ends in the second pipe section 13b.

[0034] The effective power of the heat exchanger 7 in the heat storage unit is further increased by the fact that the flow channel 6 in the area of ​​the second pipe section 13b runs vertically in a single direction. In addition, the wall 6a of the flow channel 6 has thermal insulation 18, as shown in Fig. 1 to recognize.

Claims

1. Heat exchanger having a first and second connection (8, 9), having a corrugated pipe (12) which is provided in the flow path (10) between the first and second connections (8, 9) and has a first pipe portion (13a) which is connected to the first connection (8) and a second pipe portion (13b) which adjoins this first pipe portion (13a) and extends helically, characterized in that the heat exchanger (7) has a stiffener (14) provided in the corrugated pipe (12), which runs in the first pipe portion (13a) and ends in the second pipe portion (13b).

2. Heat exchanger according to claim 1, characterized in that the stiffener (14) ends after a first, preferably in the second, turn (15a) of the helix (15) of the second pipe portion (13b).

3. Heat exchanger according to claim 1 or 2, characterized in that the stiffener (14) is designed as an inner pipe (14a).

4. Heat exchanger according to claim 1, 2, or 3, characterized in that the first and / or second connection (8, 9) has a connecting piece (16), and in that a fluid-tight press fit (17) is provided between the connecting piece (16) and the corrugated pipe (12).

5. Heat exchanger according to claim 4, characterized in that the corrugated pipe (12) is provided between the connecting piece (16) and the stiffener (14), and in that the press fit (17) is formed between the connecting piece (16), the corrugated pipe (12) and the stiffener (14).

6. Heat exchanger according to one of claims 1 to 5, characterized in that the stiffener (14) in the pipe portions (13a, 13b) rests loosely against the corrugated pipe (12).

7. Heat exchanger according to one of claims 1 to 6, characterized in that the corrugated pipe (12) has a third pipe portion (13c) which is connected to the second connection (9), and in that the heat exchanger (7) has a further stiffener (14) provided in the corrugated pipe (12), which extends in the third pipe portion (13c) and ends in the second pipe portion (13b).

8. Heat accumulator having a container (2) for accommodating a heat transfer medium (4) and having the heat exchanger (7) according to one of claims 1 to 7.

9. Heat accumulator according to claim 8, characterized in that the connections (8, 9) of the heat exchanger (7) are connected to external connections (80, 90) of the heat accumulator (1).

10. Heat accumulator according to claim 8 or 9, characterized in that the heat accumulator has a flow channel (6) provided in the container (2), which is designed to form free convection of the heat transfer medium (4), wherein the second pipe portion (13b) is located in the flow channel (6).

11. Heat accumulator according to one of claims 8 to 10, characterized in that the flow channel (6) is designed to extend in a direction vertically in the area of the second pipe portion (13b).

12. Heat accumulator according to one of claims 8 to 11, characterized in that the wall (6a) of the flow channel (6) has thermal insulation (18).

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