Case system and method for operating a case system

Abstract

The invention relates to a tank system (100) for storing a cryogenic fluid, in which the tank system (100) comprises a tank (101), a heating element (103), in which the tank (101) comprises an inner tank (105) and an outer tank (107), in which the inner tank (105) is spaced from the outer tank (107) by an intermediate volume (111), in which the heating element (103) is arranged between the inner tank (105) and the outer tank (107). The heating element (103) comprises a plurality of active thermal elements (113) arranged on the outer box (107), a plurality of passive thermal regions (115) formed on the inner box (105), and a control unit configured for supplying an electrical current to the plurality of active thermal elements (113) in order to heat the plurality of passive thermal regions (115).

Description

Technical Field

[0001] The invention relates to a tank system and a method for operating a tank system. Background Art

[0002] For storing cryogenic liquids, such as hydrogen, two-part tanks are known, in which an inner tank is separated from an outer tank by an intermediate volume in which a vacuum exists.

[0003] The above-described design causes so-called “boiling off” of the tank, ie, a deformation of the tank, when the fluid stored in the tank is heated, for example, by a heating element in the tank.

[0004] However, it is necessary to heat the fluid in the tank as needed in order to keep the pressure in the tank constant by evaporation of the fluid when the fluid is withdrawn from the tank. Summary of the invention

[0005] Within the scope of the present invention, a tank system and a method for operating a tank system are proposed. Features and details relating to the method according to the invention are of course also applicable to the tank system according to the invention, and vice versa, so that the disclosures concerning the various aspects of the invention can always be mutually referenced.

[0006] The invention is particularly intended to provide the possibility of a robust tank system for storing cryogenic liquids.

[0007] Therefore, according to a first aspect of the present invention, a tank system for storing a cryogenic fluid is proposed.

[0008] The box system of the present invention comprises a box and a heating element, wherein the box comprises an inner box and an outer box, wherein the inner box is separated from the outer box by an intermediate volume, wherein the heating element comprises a plurality of active thermal elements arranged on the outer box, a plurality of passive thermal areas formed in the inner box and a control unit, and wherein the control unit is configured to supply current to the plurality of active thermal elements so as to heat the plurality of passive thermal areas.

[0009] In the context of the present invention, a cryogenic fluid is understood to be in particular a fluid which has been cooled below its normal boiling point, for example -253°C.

[0010] In the context of the present invention, a control unit is understood to be a computing unit which is configured, for example, for regulating or controlling the supply of electric current to the plurality of active thermal elements.

[0011] The invention is based on the principle that an active thermal element that can be controlled or energized by electric current is arranged on a first side or outer side of the intermediate volume, and a passive thermal region that can be heated by the active thermal element is formed on a second side or inner side of the intermediate volume. In this case, the active thermal element and the passive thermal region are not directly coupled, in particular not mechanically coupled, but are coupled, for example, inductively, so that the energy for heating the passive thermal region can be transferred from the active thermal element to the passive thermal region through a vacuum that may be present in the intermediate volume, without having to provide an interface that penetrates the intermediate volume. Thus, thermal energy can be provided contactlessly in the wall of the inner box, for example, by the heating element.

[0012] The heatable passive heat regions can heat the fluid stored in the storage volume of the tank, so that the fluid evaporates and generates pressure in the tank.

[0013] For example, the inner box may be constructed of stainless steel or aluminum.

[0014] For example, the outer box may be constructed from a fabric such as carbon fiber.

[0015] It can be provided that the inner box has a plurality of deformation regions, in which the inner box extends further into the intermediate volume than in other regions of the inner box, and that a corresponding passive thermal region is formed in each deformation region of the inner box.

[0016] By virtue of the deformation region of the inner box extending further into the intermediate volume than other regions of the inner box, the intermediate volume is locally minimized, thereby minimizing the distance between the active thermal elements and the heating regions, thereby achieving particularly efficient magnetic flux and energy-efficient heating of the passive thermal regions.

[0017] It can also be provided that the inner box is also designed in layers and comprises at least a first layer and a second layer, at least one of the layers being composed of a ferromagnetic material.

[0018] The ferromagnetic material enables efficient inductive transfer of energy between the active thermal elements and the ferromagnetic material. The ferromagnetic layer can eliminate complex ferromagnetic regions that are inserted regionally in the inner box and achieve widespread dissemination of thermal energy.

[0019] As an alternative to the ferromagnetic layer, ferromagnetic regions inserted into the inner box can be provided region-by-region, thereby providing a cost-effective supply system.

[0020] It may be provided that each active thermal element is an electromagnet and each passive thermal region comprises a magnetic material.

[0021] By means of active thermal elements in the form of electromagnets and magnetic passive thermal regions, energy can be transferred from the active thermal elements to the passive heating elements by magnetic induction, in particular so-called "back induction" or corresponding magnetic fields. In this case, the magnetic field between the active thermal element and the passive thermal region penetrates the intermediate volume, even if the intermediate volume is subjected to a vacuum.

[0022] In particular, eddy currents can be induced in the corresponding passive thermal region by the active thermal element configured as an electromagnet, so that the passive thermal region heats up due to the eddy current losses. The passive thermal region heated in this way transfers thermal energy to the fluid stored in the tank. For this purpose, a time-varying magnetic field can be generated, for example, by means of the active thermal element.

[0023] It can also be provided that a vacuum exists in the intermediate volume.

[0024] The vacuum in the intermediate volume results in effective thermal insulation of the storage volume of the tank from the surroundings of the tank.

[0025] It can also be provided that a plurality of active thermal elements are arranged in the middle region on that side of the outer box which faces the inner box.

[0026] By arranging the active thermal elements in the middle region on the side of the outer box facing the inner box, the distance between the active thermal elements and the passive thermal areas is minimized, thereby optimizing the magnetic flux between the active thermal elements and the passive thermal areas or maximizing the energy efficiency when heating multiple passive areas.

[0027] In this case, the active thermal elements arranged in the central region can be connected via electrical lines to an energy source arranged outside the central region.

[0028] It can also be provided that a plurality of active thermal elements are arranged in the central region on that side of the outer box which faces away from the inner box.

[0029] Since the active heating elements are arranged in the central region on the side of the outer box facing away from the inner box, they can be connected to an energy source directly via electrical lines and without operating the inner box.

[0030] It can also be provided that the respective passive thermal region is configured for minimizing eddy current losses in the passive thermal region.

[0031] In order to maximize the eddy current losses and the resulting heat input into the storage volume of the box, the passive thermal regions can be reshaped, for example folded, in particular folded multiple times, from the base material of the inner box. By reshaping the inner box, for example by deep drawing, pressing or extrusion, the material structure of the inner box, in particular of stainless steel, can be changed in such a way that regions with ferromagnetic properties are formed in the inner box.

[0032] It can also be provided that an intermediate element is arranged between the respective active thermal element and the respective passive thermal zone, wherein the intermediate element is configured for maximizing the heating of the corresponding passive thermal zone.

[0033] On the one hand, the intermediate element, for example a metal block made of a soft magnetic material, in particular an iron ring, causes the intermediate volume between the corresponding active thermal element and the corresponding passive thermal region to be minimized. On the other hand, the intermediate element causes an optimized magnetic flux due to its magnetic properties. Therefore, the intermediate element acts as a kind of magnetic amplifier. For this purpose, the intermediate element can be configured, for example, to bunch the magnetic field lines emitted from the active thermal element and transfer them to the passive thermal region or focus them on the passive thermal region.

[0034] It may also be provided that the control unit is configured to supply current to the plurality of active thermal elements as a function of the pressure acting in the tank.

[0035] The pressure in the tank can be controlled or regulated by supplying a plurality of active thermal elements with current as a function of the pressure acting in the tank. For this purpose, the pressure can be measured, for example, by means of a pressure sensor or can be mathematically modeled, for example, as a function of the temperature in the tank and / or the state of a fuel consumer, such as a fuel cell system, which is supplied with fuel via the tank.

[0036] According to a second aspect, the invention relates to a method for operating a possible configuration of the proposed tank system.

[0037] The proposed method includes ascertaining the pressure in the tank, ascertaining the pressure difference between the ascertained pressure and a predefined target pressure, and heating a plurality of passive heat zones until the pressure difference falls below a predefined control threshold value.

[0038] In particular, the pressure in the corresponding tank can be kept constant or quasi-stable using the proposed method.

[0039] The advantages of the tank system for storing cryogenic fluids described in detail according to the first aspect of the invention are equally applicable to the method of operating the possible configuration of the tank system proposed according to the second aspect of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Further advantages, features and details of the invention are apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the accompanying drawings. The features mentioned in the claims and the description may be essential to the invention individually or in any combination.

[0041] The following schematically shows:

[0042] Figure 1 : Overview of a possible configuration of the proposed box system,

[0043] Figure 2: An overview of one possible configuration of the proposed box system, and

[0044] Figure 3 : Possible configurations of the proposed method. DETAILED DESCRIPTION

[0045] exist Figure 1 A detailed view of a tank system 100 for storing a cryogenic fluid, presently hydrogen, is shown in FIG.

[0046] The tank system 100 includes a tank 101 and a heating element 103 .

[0047] The tank 101 comprises an inner tank 105 and an outer tank 107 , wherein the inner tank 105 surrounds a storage volume 109 for storing a fluid, and the outer tank 107 surrounds the inner tank 105 .

[0048] The inner box 105 is separated from the outer box 107 by an intermediate volume 111. In the intermediate volume 111 there is a vacuum.

[0049] The heating element 103 comprises an active thermal element 113 arranged on the outer box 107 and a passive thermal area 115 arranged on the inner box 105, as well as a control unit not shown.

[0050] The control unit is configured to supply current to the active thermal element 113 in order to thereby heat the passive thermal region 115. To this end, the control unit can, for example, induce a time-varying magnetic field in the active thermal element 113, so that the passive thermal region 115 heats up due to eddy current losses, transfers thermal energy to the fluid and generates pressure in the tank 101.

[0051] For example, the active thermal element 113 is an electromagnet that generates a magnetic field when supplied with current. By supplying current in a time-varying manner, in particular with a changing polarity, a magnetic field can be generated by the active thermal element 113, which induces eddy currents in the passive thermal region 115, so that the passive thermal region 115 is heated due to eddy current losses.

[0052] The heated passive heat area 115 causes the liquid stored in the tank 101 to evaporate, thereby causing the pressure in the storage volume 109 to increase.

[0053] exist Figure 2 1 shows the structure of the box system 100, in which the inner box 105 is modified in the area of ​​the heating element 103 so that the middle area 111 is locally smaller. In addition, the active thermal element 113 is arranged on the side of the outer box 107 facing the inner box 105, so that the distance between the active thermal element 113 and the passive thermal area 115 is minimized. Therefore, a strong magnetic flux into the passive thermal area 115 can be achieved by energizing the active thermal element 113, so that the passive thermal area 115 is heated energy-efficiently.

[0054] exist Figure 3 The following table shows the method for running Figure 1 A method 200 of the box system 100 is provided.

[0055] Method 200 comprises a first ascertainment step 201 , in which the pressure in tank 101 is ascertained; a second ascertainment step 203 , in which a pressure difference between the ascertained pressure and a predefined target pressure is ascertained; and a heating step 205 , in which passive heat region 115 is heated until the pressure difference falls below a predefined control threshold value.

Claims

1. A tank system (100) for storing cryogenic fluids, in, The box system (100) comprises: - box (101), - a heating element (103), The box (101) includes an inner box (105) and an outer box (107). The inner box (105) and the outer box (107) are separated by an intermediate volume (111). The heating element (103) comprises a plurality of active heat elements (113) arranged on the outer box (107), a plurality of passive heat areas (115) formed in the inner box (105), and a control unit. The control unit is configured to supply current to a plurality of active thermal elements (113) so as to heat a plurality of passive thermal zones (115).

2. The box system (100) according to claim 1, It is characterized in that The inner box (105) has a plurality of deformation regions, in which the inner box (105) extends further into the intermediate volume (111) than in other regions of the inner box (105), and each passive heat region (115) is formed in a corresponding deformation region of the inner box (105).

3. The box system (100) according to claim 1 or 2, It is characterized in that The inner box (105) is multi-layered and comprises at least a first layer and a second layer, wherein at least one layer is made of a ferromagnetic material.

4. The tank system (100) according to any one of the preceding claims, It is characterized in that Each active thermal element (113) is an electromagnet and each passive thermal region (115) comprises a magnetic material.

5. The tank system (100) according to any one of the preceding claims, It is characterized in that A vacuum exists in the intermediate volume (111).

6. The tank system (100) according to any one of the preceding claims, It is characterized in that A plurality of active thermal elements (113) are arranged in the middle region (111) on a side of the outer box (107) facing the inner box (105).

7. The tank system (100) according to any one of the preceding claims, It is characterized in that A plurality of active thermal elements (113) are arranged in the middle region (111) on a side of the outer box (107) facing away from the inner box (105).

8. The tank system (100) according to any one of the preceding claims, It is characterized in that Each passive thermal region (115) is configured to minimize eddy current losses in the passive thermal region (115).

9. The tank system (100) according to any one of the preceding claims, It is characterized in that An intermediate element is arranged between each active heat generating element (113) and each passive heat zone (115), wherein the intermediate element is configured to maximize the heating of the corresponding passive heat zone (115).

10. The tank system (100) according to any one of the preceding claims, It is characterized in that The control unit is configured to supply electric current to a plurality of active thermal elements (113) depending on the pressure acting in the tank (101).

11. A method (200) for operating a tank system (100) according to any one of claims 1 to 10, in, The method (200) comprises: - determining (201) the pressure in the box (101), - determining (203) the pressure difference between the determined pressure and a predetermined target pressure, - heating (205) the plurality of passive heat zones (115) until the pressure difference falls below a predefined control threshold value.

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