EP4139943A1

EP4139943A1 - Power supply and method for production thereof

Info

Publication number: EP4139943A1
Application number: EP21721065.7A
Authority: EP
Inventors: Steffen Grohmann; Eugen SHABAGIN; David GOMSE; Heinz LAMBACH; Georg RABSCH; Thomas Gietzelt; Michael Stamm; Cornelia SCHORLE
Original assignee: Karlsruher Institut fuer Technologie KIT
Current assignee: Karlsruher Institut fuer Technologie KIT
Priority date: 2020-04-23
Filing date: 2021-04-22
Publication date: 2023-03-01
Also published as: JP2023522464A; DE102020205184A1; US20230155363A1; KR20220158010A; WO2021214213A1

Abstract

The invention relates to a power supply (110, 110' …) for transporting electrical energy from an energy source (144) to a device (148) or from the device (148) to the energy source (144), the energy source (144) being arranged in a warm region (142) and the device (148) being arranged in a cold region (146). The power supply (110, 110') has a stack (118) comprising at least two films (120, 120' …), each film (120, 120' …) comprising an electrically conductive material which is designed to transport the electrical energy, each film (120, 120' …) having an electrical connection which is designed to receive the electrical energy or to deliver the electrical energy, and each film (120, 120' …) comprising a plurality of flow channels (128) for conveying a fluid stream, and the fluid stream comprising a refrigerant mixture or a gas stream to be cooled or a gas stream to be liquefied. The films (120, 120', …) comprised by the stack (118) have a first flow path (134) through the flow channels (128) which is designed to receive the fluid stream at a high-pressure level from the warm region (142), and a second flow path (134') through the flow channels (128) which is designed to receive the fluid stream at a low-pressure level from the cold region (146).

Description

Power supply and process for their manufacture

Field of invention

The invention relates to a power supply and a method for its production. Furthermore, the present invention relates to at least one device comprising such a power supply for generating cryogenic temperatures and for transporting electrical energy as well as its use, in particular for cooling and operating high-temperature superconductors at a cryogenic temperature of 15 K to 90 K. However, other applications are possible. State of the art

Closed cooling to cryogenic temperatures of 15 K to 90 K is of great importance for many applications in energy technology, in particular of power supply lines for high-temperature superconductor applications. As in T. Kochburger, Cryogenic mixed refrigeration circuits for high-temperature superconductor applications,

Doctoral thesis, Karlsruhe Institute of Technology, 2019, ISBN 978-3-8439-3987-4, explained in more detail, cryogenic mixed cooling circuits are preferred for this. With the Linde-Hampson cycle in particular, cryogenic temperatures below 120 K can be achieved. The desired cooling is achieved here by the Joule-Thomson effect, which describes a temperature change during adiabatic, isenthalpic expansion of a real fluid. So that cooling can be achieved, the Joule-Thomson coefficient defined according to equation (1) has where the term (-) denotes a partial derivative of the temperature T with respect to the pressure p at constant enthalpy H and thus the expansion, has a positive value. This condition is given over a wide range of states of many fluids or can be achieved by precooling fluids. Since a reduction in temperature by more than 100 K cannot be achieved in practice or can only be achieved with low efficiency, even with large pressure differences, cryogenic temperatures below 120 K are required the fluid is pre-cooled by means of an internal countercurrent heat exchanger (recuperator) prior to expansion.

The Linde-Hampson cycle begins in a compressor in which a fluid refrigerant is compressed to a high pressure, with the resulting compression heat being released in an aftercooler to the surroundings of the compressor. The refrigerant is then cooled in a counterflow heat exchanger. In an expansion device, preferably selected from an expansion valve, a throttle capillary, an orifice and a sintered element, the refrigerant expands adiabatically to a low pressure level and, given positive _{Joule-Thomson coefficients \ i JT,} continues to cool by means of the Joule-Thomson effect away. A heat flow from an application to be cooled, in particular the high-temperature superconductor, can then be absorbed in an evaporator. Finally, the refrigerant is reheated to ambient temperature in the counterflow heat exchanger before it flows back to the compressor. If this cycle is used to cool power supplies or to liquefy low-boiling fluids such as hydrogen, a heat flow from the power supply or the fluid to be cooled is also absorbed by the refrigerant within the countercurrent heat exchanger.

In order to improve the efficiency of the Linde-Hampson cycle, the entropy generated as a result can be reduced by changes in the cycle, for example the use of multi-stage compressions, several heat exchangers or turbines for expansion. Alternatively or additionally, the thermodynamic properties of the refrigerant can be changed by adding at least one further refrigerant which has a boiling point that differs from the refrigerant. In a so-called “cryogenic mixed refrigeration cycle”, the Linde-Hampson cycle is operated with a high-boiling multicomponent mixture as the refrigerant instead of a pure substance, the cycle mainly taking place in a two-phase region of the mixture. In the event that the cycle is carried out in the form of at least two cooling stages, each cooling stage can preferably have its own high-boiling multicomponent mixture, so that the cycle in each cooling stage takes place predominantly in a two-phase region of the respective refrigerant mixture. As a result, the refrigerant mixture can reach its dew point at the warm end of its cooling stage, e.g. in the first cooling stage near the ambient temperature, whereby it is then successively condensed during the cooling process and further subcooled after passing the boiling point. The Joule-Thomson expansion thus takes place partly undercooled, partly with high proportions of liquid. By choosing the composition of the refrigerant mixture of a cooling stage, the effective heat capacity of the Refrigerant flows of the relevant cooling stage in the countercurrent heat exchanger are controlled in such a way that the temperature difference between the refrigerant flows of the cooling stage, preferably to a refrigerant mixture of at least one further cooling stage or to a gas flow to be liquefied or cooled, preferably over the entire flow length of the countercurrent heat exchanger, reduced to a minimum. Another aspect can be the disintegration of the fluid into two liquid phases, which occurs with some refrigerant mixtures. The two liquid phases can differ in terms of polarity, degree of fluorination or chain length of their components.

In order to achieve efficient cooling, the thermodynamic properties of the refrigerant mixture used can be adjusted accordingly for a cooling stage. An efficient refrigerant mixture has a dew point which, at high pressure level, is close to the recooling temperature of the relevant cooling stage. While the re-cooling temperature in the first cooling stage is usually in the range of the ambient temperature, in multi-stage processes the re-cooling temperature of a cooling stage is in the range of the cooling temperature generated by the isenthalpic expansion of the upstream cooling stage. The temperature of the dew point of a cooling stage can be influenced in particular by the choice and proportions of higher-boiling components for the cooling stage in question. The boiling temperature of the refrigerant mixture of a cooling stage should preferably be at the low pressure level just below the cooling temperature in order to keep the entropy generation as low as possible due to a high proportion of liquid during expansion in the expansion device. The selection and proportions of lower-boiling components have a considerable influence on the boiling temperature. In order to achieve the desired high efficiency at the temperature ranges specified above, the refrigerant mixture of a cooling stage thus comprises both higher-boiling components and lower-boiling components, whereby the refrigerant mixture of a cooling stage is high-boiling overall. In practice, the refrigerant mixture of the first stage can therefore preferably comprise about four to five refrigerants with higher boiling points and lower boiling points, preferably selected from hydrocarbons and fluorinated hydrocarbons, which are mixed in a ratio adapted for the intended application, and preferably proportions of low-boiling components, in particular selected from oxygen, nitrogen, argon, neon, hydrogen and helium. The refrigerant mixture that is used for a further cooling stage, which is precooled by a preceding cooling stage, can in practice comprise about two to four refrigerants with higher and lower boiling points, preferably selected from oxygen, nitrogen, argon, neon, hydrogen and helium that are in a customized for the intended application Ratio are mixed, in each case no components are selected that can freeze out at temperatures in the cooling stage in question.

The use of a high-boiling refrigerant mixture thus enables the refrigerant mixture to successively partially condense on the high-pressure side of a countercurrent heat exchanger, while it successively partially evaporates on the low-pressure side of the countercurrent heat exchanger. By selecting the components for the refrigerant mixture and adjusting their concentrations, an advantageous adjustment of capacity flows on the high pressure side and on the low pressure side of the countercurrent heat exchanger can thus take place. The composition of the refrigerant mixture can be optimized to such an extent that the heat transfer can take place over the entire temperature range with a minimal temperature difference DT between the material flows, whereby a considerable increase in efficiency can be achieved.

To transfer the highest possible power Q from the warm side to the cold side of the cooling stage, based on heat transfer kinetics according to equation (2)

Q = a A AT, (2) where a is a heat transfer coefficient, it can be derived that, due to a minimal temperature difference DT, a counterflow heat exchanger which has a very large transfer area A is preferred. It would therefore be advantageous to specify a countercurrent heat exchanger which has a transfer area A which is as large as possible.

Furthermore, current leads are known from the prior art which are used to transfer electrical energy, in particular in the form of an electrical current, from an energy source which is located in a warm area of the cooling stage, in particular at room temperature, to an application which is arranged in a cold area, in particular at a cryogenic temperature of 15 K to 90 K. Here, depending on the cooling method used, a power supply can be cooled with exhaust gas or operated with cooling. In power-cooled power supply lines, cooling is usually carried out in a simple but inefficient manner only at the cold end, in particular by means of a cryocooler or a low-boiling liquid. By using multi-stage cooling, efficiency can be gradually improved, but the technical effort increases at the same time. In addition, other types of cooling are known, in particular using Peltier elements, see, for example, S. Yamaguchi, M. Emoto, T. Kawahara, M. Hamabe, H. Watanabe, Y. Ivanov, Jian Sun, N. Yamamoto, A. Iiyoshi, A Proposal of Multi-stage current lead for reduction of heat leak, Physics Procedia 27 (2012) 448-451.

E. Shabagin and S. Grohmann, Development of 10 kA Current Leads Cooled by a Cryogenic Mixed-Refrigerant Cycle, IOP Conf. Series: Materials Science and Engineering 502 (2019) 012138, doi: 10.1088 / 1757-899X / 502 / l / 012138, describe a multi-tube-in-tube countercurrent heat exchanger that is wrapped around a copper core whose length is more than 1.2 m. To cool a superconducting application to a temperature level of approx. 80 K, the cold end is also placed in a cryocooler or liquid nitrogen. A shorter connection to the cold end would cause a temperature reduction, which could lead to an undesirable freezing out of the refrigerant mixture.

Dmitri Goloubev, cooling a resistive HTSL short-circuit current limiter with a mixture Joule-Thomson refrigeration machine, dissertation, Technical University Dresden, 2003, after analyzing and optimizing the power supply at liquid nitrogen temperature level, is mainly concerned with investigating a mixture nitrogen cascade as a cooling supply system for a resistive HTSL current limiter. In the summary, it is proposed to avoid direct contact between the power supply and the mixture-cooling flow, which contains combustible components, and to reduce pressure losses on the low-pressure side of the mixture-cooling machine. The optimal combination is a relatively long power supply and a nitrogen cooling stream with a relatively small liquid content of approx. 15% at the cold end of the power supply.

D. Gomse, A. Reiner, G. Rabsch, T. Gietzelt, JJ Brandner, S. Grohmann, Micro-structured heat exchanger for cryogenic mixed refrigerant cycles, IOP Conf. Series: Materials Science and Engineering 278 (2017) 012061, doi: 10.1088 / 1757-899X / 278 / l / 012061, describe a microstructured counterflow heat exchanger that comprises 60 thin plates made of stainless steel that are connected by diffusion welding in the form of a stack. By means of an etching process, 50 parallel flow channels with a channel width of 400 μm, a channel depth of 200 μm and a channel length of 20 cm are introduced into each plate pm train. Furthermore, each plate has four positioning holes for aligning the plates and four cut-out areas that form headers. DE 10 2016 011 311 A1 discloses a method for cooling a power supply of a consumer with cryogenic gas, the power supply being designed as a plate heat exchanger and the cryogenic gas being passed through the plate heat exchanger as a coolant. The structure of a gas-cooled power supply, which is designed as a plate heat exchanger, is also described.

DE 102005 005 780 A1 discloses a current-carrying device for a low-temperature conductor with at least one electrical conductor which has a warm and a cold contact point connected to the low-temperature conductor and with at least one coolant channel which is delimited at least on one side by the conductor. It is proposed that the coolant channel has guide elements with which a directed convection of the coolant in the coolant channel from the cold contact point to the warm contact point can be enforced and the speed of the coolant can be adjusted locally.

DE 199 04 822 CI discloses that in one method, a cryogenic gas is conducted as the first refrigerant in a first circuit and that the power supply lines or the consumers with power supply lines are cooled directly with the aid of the cryogenic gas, with the cryogenic gas flowing in countercurrent to the inflowing Heat is passed along the Stromzu guides and wherein the first refrigerant is cooled with a second refrigerant, which second refrigerant is guided in a second, separate circuit.

DE 21 63 270 C discloses a power supply for electrical devices with conductors cooled to low temperature, the end of which is connected to a normal conductor which is arranged in a gas flow of an evaporated cooling medium, the gas flow of the evaporated cooling medium being divided into individual flows, each one Flow through the flow channel, which is limited by at least two walls made of electrically insulating material, the distance between which is not more than 30 mm.

US 4,992,623 A discloses an electronic system with low temperature components at different locations within the system, with cryogenic fluid and electrical power being distributed by means of the same conduit. The line consists of a feed section and a return section, each section comprising a channel for conveying the cryogenic fluid with superconducting walls for conveying the electrical power. Alternatively, the line can comprise a copper rod with channels formed therein for the transport of the cryogenic fluid and a channel for receiving a rod made of superconducting material. The superconducting rod conducts the electrical current to a subsystem while it is cooled by the cryogenic fluid where the cryogenic fluid continues to be used for cooling purposes at its destination. Still alternatively, cryogenic fluid can be transported by a pair of concentric conduits, with the walls of each conduit comprising superconducting material for simultaneously providing electrical power to the subsystems using the cryogenic fluid.

WO 2003/081104 A2 discloses a method for producing a sheath for a high-temperature multifilament superconductor cable. The jacket is produced by co-extrusion of a cylindrical blank with at least two concentric cylinders. Furthermore, a sheath for a high-temperature multifilament superconductor cable is proposed, which is produced according to the method mentioned. The jacket consists of a tube with a multilayer wall comprising: a pure silver inner layer and at least one second silver-based alloy layer.

Based on this, the object of the present invention is to provide a power supply and a method for its production as well as a device for generating cryogenic temperatures and for transporting electrical energy and its use, which at least partially overcome the listed disadvantages and limitations of the prior art .

In particular, in comparison to the prior art, significantly more compact and efficient power supply lines are to be provided, which make it possible to dissipate any power loss that occurs as directly as possible at the location where it can be converted into heat. Here, the heat should be able to be dissipated at the highest possible temperature level in each case, in order to achieve a thermodynamic increase in efficiency compared to the prior art, according to which the cooling of the power supply takes place either only at its cold end or with higher temperature differences to a gas flow.

Disclosure of the invention

This object is achieved by a power supply and a method for its production as well as a device for generating cryogenic temperatures and for transporting electrical energy and its use according to the features of the independent claims. Advantageous developments, which can be implemented individually or in any combination, are presented in the dependent claims. In the following, the terms “have”, “have”, “comprise” or “include” or any grammatical deviations therefrom are used in a non-exclusive manner. Accordingly, these terms can relate to situations in which, apart from the features introduced by these terms, no further features are present, or to situations in which one or more further features are present. For example, the term "A has B", "A has B", "A comprises B" or "A includes B" can refer to the situation in which, apart from B, no further element is present in A (ie on a situation in which A consists exclusively of B), as well as on the situation in which, in addition to B, one or more further elements are present in A, for example element C, elements C and D or even further elements .

It is also pointed out that the terms “at least one” and “one or more” as well as grammatical modifications of these terms, if they are used in connection with one or more elements or features and are intended to express that the element or feature is provided once or several times can be used, as a rule, only once, for example when the feature or element is introduced for the first time. If the feature or element is subsequently mentioned again, the corresponding term “at least one” or “one or more” is generally no longer used, without this limiting the possibility that the feature or element can be provided once or several times.

Furthermore, the terms “preferably”, “in particular”, “for example” or similar terms are used below in connection with optional features, without this limiting alternative embodiments. Features introduced by these terms are optional features, and it is not intended to use these features to restrict the scope of protection of the claims and in particular of the independent claims. Thus, as the person skilled in the art will recognize, the invention can also be carried out using other configurations. In a similar way, features which are introduced by “in an embodiment of the invention” or by “in an exemplary embodiment of the invention” are understood as optional features, without any intention hereby to limit alternative configurations or the scope of protection of the independent claims. Furthermore, these introductory expressions are intended to leave unaffected all possibilities for combining the features introduced thereby with other features, be they optional or non-optional features. In a first aspect, the present invention relates to a power supply for transporting electrical energy from an energy source to an application or from the application to the energy source, the energy source being arranged in a warm area and the application being arranged in a cold area,

- wherein the power supply has a stack comprising at least two foils,

- wherein each film comprises an electrically conductive material which is set up to transport the electrical energy,

- each film having an electrical connection which is set up to receive the electrical energy or to output the electrical energy,

- wherein each film comprises a plurality of flow channels for guiding a fluid flow.

Here, the term “power supply” denotes a device that is set up to transport electrical energy, in particular in the form of an electrical current, from at least one energy source to at least one application or from the at least one application to the at least one energy source. With regard to the present invention, the power supply is set up in particular to transport an electric current from a normally conducting circuit that includes the at least one energy source into an electric circuit that includes at least one superconductor, in particular a high-temperature superconductor, preferably around one To enable loss-free further transport of the electrical current in the at least one superconductor, in particular in the at least one high-temperature superconductor. However, other types of applications are conceivable.

According to the invention, the energy source is located in a warm area of a cooling stage of a device for generating cryogenic temperatures, which can also be referred to as a “refrigeration system”, while the application is arranged in a cold area. In principle, every device for generating cryogenic temperatures comprises at least one cooling stage, each of which has a cold area and a warm area. Here, the “warm area” denotes a first sub-area of the device which has a higher temperature compared to the cold area. In the case of at least two cooling stages, the device can be designed in such a way that at least part of the warm area of the respective subsequent cooling stage can correspond to the cold area of the respective preceding stage. The warm area of the first cooling stage, also referred to as the “pre-cooling stage”, is preferably set up for ambient temperature and is usually kept at least at ambient temperature, with higher temperatures, for example up to 150 ° C., also occurring in a compressor in particular. The term the “ambient temperature” here relates to a temperature of 273 K, preferably 288 K, particularly preferably 293 K, to 313 K, preferably up to 303 K, particularly preferably up to 298 K.

In contrast, the “cold area” denotes a further sub-area of the relevant cooling stage of the device, which is set up for a cryogenic temperature and is intended to be used to generate the respective cryogenic temperature. The term “cryogenic temperature” here includes a temperature of 10 K, preferably 15 K, to 120 K, preferably up to 90 K. In particular, the cold area is used to bring the cold area to a cryogenic temperature and to keep it at a cryogenic temperature Area in a cryostat, preferably a vacuum-insulated cryostat, introduced. However, other types of cryostat are possible.

According to the invention, the power supply has a stack which comprises at least two foils. The term “foil” here refers to a thin, expanded body of an electrically conductive material that is designed to transport electrical energy. The film can preferably have a surface in the form of a lateral extension, comprising a film length and a film width, the film width being a film thickness formed perpendicular to the lateral extension by a factor of at least 10, preferably at least 25, particularly preferably at least 50, in particular at least 100 can exceed. Preferably, the film

a film length of at least 5 cm, preferably of at least 10 cm, in particular from 20 cm to 25 cm, up to at most 1 m, preferably up to at most 50 cm;

a film width of at least 2 cm, preferably of at least 5 cm, in particular from 10 cm to 20 cm, at most up to 50 cm, preferably at most up to 25 cm; and

- have a film thickness of at least 200 μm, preferably of at least 250 μm, in particular from 400 μm to 500 μm, at most up to 2 mm, preferably at most up to 1 mm. Particularly for the selection of the film thickness, it is advantageous to note that, as explained in more detail below, these are connected to one another by means of diffusion welding and are therefore designed in such a way that they can withstand the associated energy input without damage or even destruction. In principle, however, other values for the film length, film width and film thickness are also conceivable; However, it is particularly advantageous if the film thickness does not exceed the specified value of 1 mm, from which it would more likely be referred to as “plate thickness”.

The term “stack” relates to an arrangement which contains the at least two foils, each of which is placed on top of one another in the lateral extent parallel to their surfaces are preferably connected to one another by means of diffusion welding, comprises. In particular, in order to avoid a protrusion between adjacently arranged foils in the stack, all foils of the stack can preferably have the same foil length and the same foil width. In order, as explained in more detail below, to enable the electrical current to be distributed as uniformly as possible in accordance with Kirchhoff's laws to as many foils in the stack as possible, all foils in the stack can also preferably have the same foil thickness. The stack can comprise at least two foils, preferably at least 10 foils, particularly preferably at least 25 foils, in particular 50 to 60 foils, up to 250 foils, preferably up to 200 foils, particularly preferably up to 100 foils. However, another value for the number of slides in the stack is possible. As a result, in particular the number, film length, film width and film thickness of the films can be adapted to a level of electrical energy to be transported by means of the power supply, in particular an expected current strength.

As already mentioned, each film comprises an electrically conductive material that is designed to transport electrical energy. A material is “electrically conductive” if it enables the transport of electrical energy, in particular electrical charge carriers in the form of an electrical current, through the material. In a particularly preferred embodiment, the electrically conductive material comprises a metal, in particular a highly conductive metal, which has an electrical conductivity s of at least 10 ⁶ S / m, preferably of at least 10 ⁷ S / m, preferably of at least 2 · 10 ⁷ S / m , having. These metals include in particular copper (s ~ 5.8 · 10 ⁷ S / m), aluminum (s ~ 3.7 · 10 ⁷ S / m) and brass (s ~ 2.4 · 10 ⁷ S / m), copper and aluminum are particularly preferred. Due to its lower electrical conductivity s <10 ⁷ S / m, stainless steel is less preferred.

Furthermore, copper is particularly preferred over aluminum, since a power supply made of copper foils has a specific surface area above 1000 m ² / m ³ up to 10,000 m ² / m ³ , while the specific surface area for aluminum plates is only 100 m ² / m ³ up to 1000 m ² / m ³ .

In order to enable the electrical energy to be absorbed from the energy source and the electrical energy to be delivered to the application, each film has an electrical connection. The term “electrical connection” here relates to a device of a film which is set up to receive electrical energy into the film and / or to output electrical energy from the film. In particular, a separate electrical connection is attached to each transverse side of the film, so that the electrical energy from the energy source or the electrical energy can be received on a first transverse side of the film the delivery of the electrical energy to the energy source and the delivery of the electrical energy to the application or the absorption of the electrical energy from the application is possible on the other transverse side of the film. The electrical connection on at least one of the transverse sides, particularly preferably on both transverse sides, of the film can preferably be designed in the form of an electrically conductive connection lug. In the context of the present invention, the term “connection lug” denotes an electrically conductive connection part set up on the relevant transverse side of the film, which is preferably in a movable shape, particularly preferably in a tapered and / or conically tapered shape, the connection part preferably being of the respective film is included. With regard to the term “electrically conductive”, reference is made to the definition above. Advantageously, each film in the stack can be contacted individually in order to allow the most uniform possible distribution of the electrical current in accordance with Kirchhoff's laws to as many films as possible in the stack. However, other types of configuration of the electrical connection are conceivable.

In a preferred embodiment, the electrical connection of the film facing the application in the cold area can have an electrically conductive connection to a high-temperature superconductor, the high-temperature superconductor being arranged between the electrical connection of the power supply and the application. The high-temperature superconductor can in particular be designed as a tape or a cable. In this way, the electrically conductive connection between the power supply and the application can be designed to be superconducting, in particular in the form of a high-temperature superconductor, in order to ensure that the electrical current is transported onward as loss-free as possible from the power supply to the application or from the application to the power supply enable. The term “high-temperature superconductor tape” here refers to an electrical conductor configured in the form of a tape, which at least partially comprises a high-temperature superconductor. The term “high-temperature superconductor cable” here refers to a cable-shaped electrical conductor which at least partially comprises a high-temperature superconductor. A high-temperature superconductor cable can comprise several filaments which can be connected in an electrically conductive manner individually or in groups to the foil or to several foils.

According to the invention, each film furthermore comprises a multiplicity of flow channels for guiding a fluid flow. In this case, the fluid flow can preferably comprise a refrigerant mixture or a gas flow to be cooled or a gas flow to be liquefied. The gas flow can here comprise a gas or any mixture of at least two gases, wherein the gas can be selected in particular from oxygen, nitrogen, argon, neon, hydrogen and helium. As mentioned at the beginning, the term des “Refrigerant mixture” means a mixture of at least two components of refrigerants, with at least two of the components having a different boiling point from one another. In the context of the present invention, the term “refrigerant” relates to a preferably inert fluid that has a positive Joule-Thomson coefficient \ i _JT > 0 when it enters the cold area of the relevant cooling stage, and is therefore used as a means for Generation of the cryogenic temperature in a cooling stage of the Linde-Hampson cycle is suitable. In order to be able to achieve a high level of efficiency, especially when cooling around the above-mentioned temperature range from around 300 K to 15 K to 90 K, the refrigerant mixture for the respective cooling stage comprises both higher-boiling components and lower-boiling components, which means that the refrigerant mixture as a whole is " far-boiling "can be designated. The refrigerant mixture for each cooling stage therefore preferably comprises at least two, preferably at least three, particularly preferably at least four, to eight, preferably up to six, preferably up to five refrigerants, with at least one of the refrigerants being a higher-boiling component and at least one other refrigerant being a lower-boiling component . The term “higher boiling” refers to fluids whose boiling point is at the temperature at the entry into the cold area of the respective cooling stage. For the term “cold area”, reference is made to the definition above. The term “lower-boiling” refers to fluids whose boiling point is below the temperature of the higher-boiling component of the respective cooling stage. The lowest-boiling component of the refrigerant mixture of the respective cooling stage has a boiling temperature which is below the temperature after the isenthalpic expansion of the respective cooling stage and can thus in particular be a cryogenic temperature. For the term “cryogenic temperature”, reference is made to the definition above. For the pre-cooling stage in particular, the at least one higher-boiling component can preferably be selected from a hydrocarbon and a fluorinated hydrocarbon, while the at least one lower-boiling component can preferably be selected from oxygen, nitrogen, argon, neon, hydrogen and helium. The refrigerant mixture for a further cooling stage, which is precooled by a preceding pre-cooling stage, can preferably comprise a refrigerant selected from oxygen, nitrogen, argon, neon, hydrogen and helium, which are preferably mixed in a ratio adapted for the intended application, preferably In each case those components are avoided which can freeze out at the temperatures in the relevant cooling stage. Other types of refrigerants are possible.

As already mentioned, each film for guiding the fluid flow comprises a multiplicity of flow channels. The term “flow channel” here refers to an elongated depression made in the respective film, which extends over the entire length in particular Film length of the film in question, in particular minus at least one entry area and at least one exit area, and which is therefore for receiving the fluid flow from a first area, selected from the warm area or the cold area of a cooling stage, for guiding the fluid flow over the film and is set up to deliver the fluid flow to a second area selected from the respective other area of the relevant cooling stage. Particularly preferably, the number, shape and configuration of the flow channels can be selected in such a way that the fluid flow flows through the plurality of flow channels in the foils in a laminar flow as far as possible.

The plurality of flow channels can preferably be incorporated into the respective film by means of a subtractive process, in particular selected from an etching process or from micro-milling, whereby the film in question can also be referred to as a “microstructured film”. In this case, each flow channel can in principle have any channel cross-section which has an opening towards the surface of the film. Particularly when the etching process is used, a semicircular channel cross-section is created due to the manufacturing process, while other types of channel cross-sections are also possible with micro-milling; however, production of the flow channels by means of micromilling requires a higher expenditure of time than the etching process.

Each film can comprise at least 10 flow channels, preferably at least 20 flow channels, particularly preferably at least 25 flow channels, in particular 50 to 100 flow channels, up to 500 flow channels, preferably up to 250 flow channels, particularly preferably up to 200 flow channels. However, a different number of flow channels in the film is possible. In particular, in order to simplify the production of the flow channels, all flow channels in a film, preferably in each film, can preferably have the same channel length, channel width, channel depth and web width and be arranged parallel to one another in periodic succession in the film, with

the channel length can preferably correspond to the film length of the associated film, in particular less at least one entry area and at least one exit area;

the channel width can be at least 100 μm, preferably at least 250 μm, in particular 400 μm to 500 μm, at most up to 2 mm, preferably at most up to 1 mm, a web width with which adjacent flow channels are spaced apart from one another, at least 0.5, preferably can be at least 1.0, in particular from 1.0 to 2.0, at most 5.0, preferably at most 2.5 of the channel width of the flow channels; and the channel depth at least 50 μm, preferably at least 100 gm, in particular from 200 gm to 250 gm, at most 1 mm, preferably at most 500 gm, but less than the film thickness, preferably less than 75% of the film thickness, particularly preferably less than 50% the film thickness, so that a sufficient bottom thickness of the film can remain, wherein a ratio of channel width to channel depth, in particular when using an etching process, can be preferably from 1.0 to 3.0, in particular from about 2.0, while other values are possible when using micro-milling. However, other values for the channel length, channel width and channel depth of the flow channels are conceivable.

As already mentioned above, it can also be advantageous to ensure that the foils are connected to one another by means of diffusion welding and therefore in particular have a sufficient base thickness and web width so that the foils can withstand the associated energy input without damage or even destruction. Diffusion welding also has the advantage that as a result the stack of foils comprises only one uniform material; in particular, a solder can be dispensed with as a further material in the stack. In this way, a monolithic design can be provided with which thermal voltages, which can lead to leaks during the operation of the power supply lines, can be effectively prevented.

Regardless of the type of configuration of the flow channels, the flow channels are each preferably introduced exclusively on a single side of the surface of each film. Adjacent foils, in particular foils which are assigned to different flow paths, can thus be introduced into the stack in such a way that the openings of the flow channels on the surface of the foils are arranged facing away from one another. In this way, an offset, as described in Gomse et al., See above, between flow channels of adjacent foils arranged facing one another can be avoided. Reference is made to the exemplary embodiments for further details of the arrangement of the foils in the stack, which can also be referred to as “stacking”. In principle, however, a different arrangement of the flow channels in individual or all foils is also conceivable, including an arrangement of the flow channels on both sides of a foil, which, however, is usually associated with disadvantages, in particular an offset or higher manufacturing costs.

The foils included in the stack have

- A first flow path through the flow channels, which is set up to receive the refrigerant mixture at high pressure level from the warm area of the cooling stage; and - A second flow path through the flow channels, which is set up to receive the refrigerant mixture at low pressure level from the cold area of the cooling stage, or to receive a liquid phase of the refrigerant mixture at low pressure level from the cold area of the cooling stage. In contrast to the known prior art, it is a countercurrent heat exchanger with high pressure flow and low pressure flow of the cooling medium, the high pressure flow from the warm area into the cold area in the direction of flow of the electrical current, while the low pressure flow in the opposite direction from the cold Area flows into the warm area.

In addition, the foils comprised by the stack can preferably have at least one further flow path selected from:

- A third flow path through the flow channels, which is set up to receive a vapor phase of the refrigerant mixture at low pressure level from the cold region of the cooling stage;

- A fourth flow path through the flow channels, which is set up to receive the gas flow to be cooled or the gas flow to be liquefied from the warm region of the cooling stage.

In this embodiment, a vapor phase and a liquid phase of the refrigerant mixture can preferably be recorded separately.

In a preferred embodiment, the flow channels of each film can be used either as a first flow path for receiving the refrigerant mixture at high pressure level from the warm area, as a second or third flow path for receiving the refrigerant mixture at low pressure level from the cold area, or as a fourth flow path for Be set up to accommodate the gas flow to be cooled or liquefied from the warm area of the cooling stage. By adapting the geometry of the flow channels and / or a ratio of the number of foils which comprise the first flow path to the number of foils which comprise the second, third or fourth flow path, pressure losses and heat transfer surfaces can be adjusted in a simple manner.

With regard to an order of the arrangement of the foils in the stack, the following configurations in particular can be preferred:

The flow channels of adjacent stacked foils in the stack can be set up alternately as a first flow path for receiving the refrigerant mixture at high pressure level and as a second flow path for receiving the refrigerant mixture at low pressure level. - The flow channels at most two adjacent stacked foils in the stack can be set up as a first flow path for receiving the refrigerant mixture at high pressure level, while an adjoining further foil has second or third flow paths for receiving the refrigerant mixture at low pressure level.

- The flow channels at most two adjacent stacked foils in the stack can be set up as a second or third flow path for receiving the refrigerant mixture at low pressure level, while a further foil adjoining them flow channels in the first flow path for receiving the refrigerant mixture at high pressure level or in the fourth Has flow path for receiving the gas flow to be cooled or liquefied from the warm area of the cooling stage.

- The flow channels at most two adjacent stacked foils in the stack can be set up as a fourth flow path for receiving the gas flow to be cooled or liquefied from the warm area of the cooling stage, while an adjoining further foil flow channels in the first flow path for receiving the refrigerant mixture at high pressure Level, or in the second or third flow path for receiving the refrigerant mixture at low pressure level.

However, further configurations of the arrangement of the foils in the stack are possible. Such a layered or intermittent alternating arrangement of the first and second flow paths, and optionally the third flow paths and / or the fourth flow paths, enables countercurrent flow through the stack to be achieved.

Each foil has an entry area and exit area for the flow channels, the "entry area" denoting a first section of the foil which adjoins a first area of the flow channels that is set up for the fluid flow to enter the flow channels, while the "exit area" denotes a second section of the film which adjoins a second region of the flow channels which is set up for an exit of the fluid flow from the flow channels. In a preferred embodiment, the inlet area and / or the outlet area can have a distribution element which is set up to divide the fluid flow over the flow channels of the film, which are preferably arranged in parallel. In particular to achieve uniform distribution of the fluid flow over the flow channels, the distribution element can preferably have a plurality of periodically arranged elevations and depressions located between them. The elevations can preferably assume the same level as the surface of the film, while the depressions can preferably have the same channel depth as the flow channels. The distribution elements can advantageously serve in particular to prevent a maldistribution of the flow during operation during the distribution of the fluid flow over several parallel flow channels. The distribution element can be introduced into the film together with the introduction of the flow channels.

In a preferred embodiment of the present invention, one side, preferably both sides, of the stack can be provided with a cover plate. Here, at least one of the cover plates can have at least one feed line for feeding the fluid flow into the flow channels of the stack and one discharge line for discharging the fluid flow from the flow channels of the stack. To produce the supply line and / or the discharge line, the cover plate can initially only have corresponding nozzles, to which the supply line and / or the discharge line are fastened, before it is used in the power supply. A brazed connection to a pipe section and a subsequent pipe screw connection, in particular by means of cutting ring seals or clamping ring seals, or a welded connection can preferably be used here.

In a further aspect, the present invention relates to a device for generating cryogenic temperatures and for transporting electrical energy from an energy source to an application or from the application to the energy source, comprising at least one cooling stage which has a warm area and a cold area, wherein in the warm area is provided with a refrigerant mixture set up for the respective cooling stage and an energy source, the refrigerant mixture having at least two components with boiling temperatures that differ from one another, the cold region comprising at least one cooling stage:

- At least one power supply as described above or below, the power supply having at least one first flow path for receiving the refrigerant mixture at high pressure level from the warm area of the cooling stage and at least one second flow path for receiving the refrigerant mixture at low pressure level from the cold region of the cooling stage having, wherein the at least one power supply is set up as a first heat exchanger at the same time;

- At least one expansion device which is set up to expand and cool the refrigerant mixture to the low-pressure level; and

- The application that is set up to receive the electrical energy and / or to deliver the electrical energy. In this case, the cold area of at least one cooling stage, which is set up for a cryogenic temperature and is used as intended to generate the cryogenic temperature, can preferably be introduced into a cryostat, in particular into a vacuum-insulated cryostat.

First of all, the cold area of the relevant cooling stage comprises at least one power supply, described in more detail above or below, which is simultaneously set up as a first heat exchanger, which is designed in particular as a countercurrent heat exchanger. The term “heat exchanger” refers to any device configured to bring about a transfer of thermal energy from at least one high-pressure substance flow to at least one low-pressure substance flow. The term “thermal energy” here relates to an energy of the respective material flow, which can essentially be described as a function of the temperature of the relevant material flow. In the context of the present invention, both the at least one high-pressure substance flow and the at least one low-pressure substance flow comprise the refrigerant mixture used for the respective cooling stage, the substance flows differing from one another in a temperature of the refrigerant mixture or the refrigerant mixtures. In addition, the at least one high-pressure substance flow can comprise a gas flow to be cooled or a gas flow to be liquefied. The at least one low-pressure material flow of the lowest stage has a lowest temperature in each section of the heat exchanger, followed by the temperature of the at least one low-pressure material flow of an optional precooling stage. The at least one high-pressure material flow has a temperature in each section of the heat exchanger which is above the at least one low-pressure material flow. Furthermore, the term “counterflow heat exchanger” relates to a special type of heat exchanger in which the high-pressure substance flow adopts a direction that is opposite to the direction of the low-pressure substance flow. A particularly cold material flow can thus advantageously meet a particularly warm material flow, whereby a transfer of thermal energy from the at least one high-pressure material flow to the at least one low-pressure material flow can be configured as efficiently as possible.

The first heat exchanger comprised according to the invention by the cold area of the relevant cooling stage accordingly has a first sub-area designated as the “high pressure side” and a second sub-area designated as the “low pressure side”, the high-pressure side for receiving the refrigerant mixture and optionally the gas flow from the warm area of the relevant Cooling stage and the low-pressure side set up for the delivery of the refrigerant mixture to the warm area of the relevant cooling stage are. Thus, the refrigerant mixture supplied on the high pressure side from the associated warm area has a higher temperature compared to the refrigerant mixture provided on the low pressure side for delivery to the associated warm area. Consequently, the refrigerant mixture provided on the low-pressure side contributes significantly to cooling the refrigerant mixture supplied on the high-pressure side from the associated warm area and the optionally supplied gas flow, whereby the transfer of thermal energy can be made more efficient by the counterflow heat exchanger preferably used. In addition to the thermal energy from the high pressure side of the relevant stage, the refrigerant mixture on the low pressure side of the relevant stage can absorb thermal energy from further material flows, for example from the high pressure side of a downstream cooling stage or from the cooling or liquefaction of a gas flow to be cooled or liquefied.

The refrigerant mixture enters the first heat exchanger at the high pressure level on the high pressure side, while the refrigerant mixture is provided on the low pressure side at the low pressure level. The term “high pressure level” here denotes a pressure level that acts on the refrigerant mixture present there, the pressure of which has a value that exceeds the value of the pressure that acts on the refrigerant mixture provided on the low-pressure side. In particular, the high pressure level of the cooling stage can have an absolute pressure of 1 bar, preferably 10 bar, particularly preferably 25 bar, to 150 bar, preferably up to 25 bar, particularly preferably up to 20 bar, while the low pressure level of the cooling stage may have an absolute pressure of 100 mbar, preferably 1 bar, particularly preferably 2 bar, to 50 bar, preferably up to 10 bar, particularly preferably up to 5 bar. However, other values both for the high pressure level and for the low pressure level are possible, in particular depending on the refrigerant mixture used for the respective cooling stage.

Furthermore, the cold area of the relevant cooling stage comprises at least one expansion device which is set up to expand and cool the refrigerant mixture to the low-pressure level. Here, the desired cooling of the refrigerant mixture may preferably by the Joule-Thomson effect can be obtained, wherein the equation (1) defined Joule-Thomson coefficient \ i _JT of the refrigerant mixture becomes a positive value. The at least one expansion device thus causes, on the one hand, the reduction of the pressure acting on the refrigerant mixture from the high pressure level to the low pressure level and, on the other hand, the desired further cooling of the refrigerant mixture. The at least one expansion device can preferably be selected from an expansion valve, a throttle capillary, a Aperture and a sintered body. However, it is conceivable to use a different expansion device.

In addition, the cold area of the at least one cooling stage can preferably comprise at least one second heat exchanger, which is set up to cool the application, preferably the superconducting application, which is arranged in the cold area.

In a further aspect, the present invention relates to a method for producing a power supply, in particular a power supply described above or below, which is set up to transport electrical energy from an energy source to an application or from the application to the energy source, the energy source being in a warm Area is arranged and wherein the application is arranged in a cold area, wherein the method comprises the following steps: a) Providing at least two foils, wherein each foil comprises an electrically conductive material which is set up to transport electrical energy, wherein each film has an electrical connection at each end which is set up to receive electrical energy from an energy source or to deliver electrical energy to an application; b) introducing a multiplicity of flow channels, which are set up to receive a fluid flow, into the at least two foils; c) Arranging the at least two foils in the form of a stack and diffusion welding the at least two foils, the electrical connection of each foil remaining unwelded in the cold area.

The introduction of the multiplicity of flow channels into the at least two foils in accordance with step b) can here preferably take place by means of an etching process or by means of micro-milling. As mentioned above, the fluid flow can preferably comprise a refrigerant mixture or a gas flow to be cooled or a gas flow to be liquefied.

While the electrical connections of the foils can be welded to one another in the warm area, the electrical connections of the foils in the cold area remain unwelded so that the high-temperature superconductors, as mentioned above, can advantageously be contacted individually.

Arranging the at least two foils in the form of a stack in accordance with step c) can preferably include attaching at least one cover plate to at least one side of the stack, preferably one cover plate on both sides of the stack, wherein the diffusion welding of the at least two foils also includes the at least one cover plate, preferably the two cover plates, wherein the method can have the further step: d) introducing in each case at least one feed line, which is set up to feed the fluid flow, and at least one Discharge, which is set up to discharge the fluid flow, into at least one of the cover plates.

Furthermore, the present method can preferably have the following further step: e) Attaching at least one high-temperature superconductor to the electrical connection of the foils at the cold end, which is set up to deliver the electrical energy to the application.

The high-temperature superconductor can in particular be designed as a tape or a cable.

For further details with regard to the present method and the terms used here, reference is made to the description of the power supply according to the invention.

In a further aspect, the present invention relates to a use of a device for generating cryogenic temperatures and for transporting electrical energy for cooling and operating high-temperature superconductors at a temperature of 15 K to 90 K.

For further details with regard to the present use, reference is made to the description of the device according to the invention.

The power supply according to the invention, the method for its production and the device for generating cryogenic temperatures and for transporting electrical energy from an energy source and its use have a number of advantages over known power supplies, associated methods and corresponding devices. The power supply proposed here, as a uniform component, performs a double function, which at the same time includes a power supply and a heat transfer. In comparison to the prior art, in particular, significantly more compact and efficient power supply lines can be provided, which allow power loss that occurs to be dissipated directly at the location where it can be converted into heat. Here, the heat can be dissipated at the highest possible temperature level, so that there is an increase in efficiency an exclusive cooling at the cold end of the power supply, a step-by-step cooling or cooling by a gas flow occurs.

Brief description of the figures

Further details and features of the present invention emerge from the following description of preferred exemplary embodiments, in particular in connection with the dependent claims. The respective features can be implemented individually or in combination with one another. However, the invention is not restricted to the exemplary embodiments. The exemplary embodiments are shown schematically in the following figures. Here, the same reference numbers in the figures denote the same or functionally identical elements or elements that correspond to one another with regard to their functions.

Show in detail:

FIG. 1 shows schematic representations of preferred exemplary embodiments of a power supply according to the invention;

FIG. 2 shows schematic representations of preferred exemplary embodiments of an arrangement of foils within a stack in the power supply according to the invention;

FIG. 3 shows schematic representations of a preferred exemplary embodiment of a distribution element in an inlet area or outlet area for dividing a refrigerant mixture into flow channels in one of the foils of the power supply according to the invention;

FIG. 4 shows schematic representations of preferred exemplary embodiments of a single-stage device for generating cryogenic temperatures and for transporting electrical energy, the device comprising power supply lines according to the invention; and

FIG. 5 shows schematic representations of preferred exemplary embodiments of a two-stage device for generating cryogenic temperatures and for transporting electrical energy, the device comprising power supply lines according to the invention. Description of the exemplary embodiments

In the figures la and lb is a schematic representation of a preferred embodiment of a power supply 110 according to the invention shown in the form of an exploded drawing. A stack 118, the comprises a multiplicity of foils 120, as well as two individual foils 120 ′, 120 ″ (FIG. 1 a) or three individual foils 120 ′, 120 ″, 120 ′ ″ drawn, which are also set up for inclusion in the stack 118.

As can be seen from FIGS. 1 a and 1 b, the foils 120 are each placed on top of one another in the lateral extent parallel to their surfaces and can preferably be connected to one another by means of diffusion welding. In particular, all foils 120 of the stack 118 can preferably have the same foil length and the same foil width in order to avoid a protrusion between adjacent foils 120 in the stack 118. In addition, in order to distribute a flow of electrical energy as evenly as possible over all foils 120 in the stack 118, all foils 120 of the stack 118 can also preferably have the same foil thickness. The number, film length, film width and film thickness of the films 120 can preferably be adapted to the level of the electrical energy to be transported by means of the power supply 110. As mentioned above, the stack 118 can in particular comprise 10 to 100 foils 120; however, another value for the number of foils 120 in the stack 118 is possible.

Each film 120, 120 ', 120 ", 120'" has an electrically conductive material that is designed to transport electrical energy. With regard to the term “electrically conductive”, reference is made to the definition above. For this purpose, the electrically conductive material preferably comprises copper, other electrically conductive materials also being conceivable, as well as a separate electrical connection on each transverse side of each film 120, 120 ', 120 ", 120'". As FIGS. 1 a and 1 b show, a first transverse side of each film 120, 120 ', 120 ", 120'" can have a first electrical connection 122, 122 ', 122 ", 122"' for receiving electrical energy from an energy source and the other transverse side of the film 120, 120 ', 120 ", 120'" each have a second electrical connection 124, 124 ', 124 ", 124"' for delivering the electrical energy to an application to be cooled, which is used to receive the electrical energy provided in this way Energy is set up, have, wherein each first electrical connection 122, 122 ', 122 ", 122"' and every second electrical connection 124, 124 ', 124 ", 124"' is encompassed by the film in question. As also shown in FIGS. 124 ', 124 ", 124'" of each film 120, 120 ', 120 ", 120'" has an electrically conductive connection part, which is preferably movable and in a position relative to the rest of the body of the film 120, 120 ', 120 ", 120' “Is at least partially tapered. However, other types of arrangement and configuration of the electrical connections of the foils 120, 120 ', 120 ", 120'" are conceivable.

As can be seen particularly well in the exemplary foils 120 ', 120' 'on the basis of the illustration in FIGS. 114 '"of the upper cover plate 112 arranged passage 126, 126', 126", 126 '", which are set up for the supply and / or discharge of the refrigerant mixture in each individual film 120, 120', 120", 120 '". Between the openings 126 'and 126 "' in the film 120 'as well as between the openings 126 and 126" in the film 120 ", in each film 120, 120', 120", 120 '"are a plurality of preferably arranged in parallel Flow channels 128, which preferably have a plurality of periodically arranged depressions and elevations located between them for guiding a refrigerant mixture on the lateral extent of the surface along the length of the film 120, 120 ', 120 ", 120'". For details of the arrangement and configuration of the flow channels 128, reference is made to the above description and to the illustration according to FIGS. 2a and 2b.

As also shown in FIGS. 1 a and 1 b, there is an inlet area 130 and an outlet area 130 'for the flow channels between the passages 126' and 126 "'as well as between the passages 126 and 126" and the associated plurality of flow channels 128 128, the choice of the arrangement of the inlet area 130 and the outlet area 130 'in the foils 120, 120', 120 ", 120 '" depending on a flow direction of the refrigerant mixture through the plurality of flow channels 128 selected during operation of the power supply 110. In the illustration in accordance with FIGS ", 126 '" provided refrigerant mixture is set up on the flow channels 128 of the film 120, 120', 120 ", 120 '". For details with regard to the arrangement and configuration of the distribution elements 132, 132 ', reference is made to the above description and to the illustration according to FIGS. 3a and 3b. FIGS. 2a and 2b show schematic representations of preferred exemplary embodiments of an arrangement of the foils 120, 120 ', 120 ", 120"' and that of the flow channels 128 within a stack 118 in the power supply 110 according to the invention the stack 118 comprised foils 120, 120 ', 120 ", 120'" preferably a first flow path 134 which is set up to receive the refrigerant mixture at high pressure level from a warm area of a cooling stage and a second flow path 134% which is used to receive the refrigerant mixture is set up at the low pressure level from a cold area of the cooling stage.

FIG. 2a schematically shows a first preferred sequence of the arrangement of the foils 120, 120 ', 120 ", 120'" in the stack 118. According to this arrangement, the flow channels 128 are adjacent stacked foils 120, 120 "or 120 ', 120'" alternately set up in the stack 118 as a first flow path 134 and as a second flow path 134 '.

FIG. 2b schematically shows a further preferred sequence of the arrangement of the foils 120, 120 ', 120 ", 120'" in the stack 118. According to this alternative arrangement, the flow channels 128 are two adjacently stacked foils 120 ', 120' 'in the stack 118 as second flow path 134 'and set up as a third flow path 134 ″ for the separate reception of a vapor phase and a liquid phase of the refrigerant mixture at low pressure level, while a further film 120, 120 ″ adjoining each other has a first flow path 134 for receiving the refrigerant mixture at high pressure level Area. The stack 118 can then be correspondingly further configured or can be continued according to the exemplary embodiment from FIG. 2a.

According to a further preferred sequence of the arrangement of the foils 120, 120 ', 120 ″, 120 ″' in the stack 118 (not shown), the flow channels 128 of two adjacent stacked foils 120 ′, 120 ″ in the stack 118 can be used as the first flow path 134 be set up to receive the refrigerant mixture at the high pressure level, while a further film 120, 120 ′ ″ adjoining it can have a second flow path 134 ′ for receiving the refrigerant mixture at the low pressure level. In addition, further configurations of the arrangement of the foils of foils 120, 120 ", 120", 120 "" in stack 118 are conceivable.

Figures 3a to 3c show schematic representations of a preferred embodiment for the distribution element 132 in the inlet area 130 or in the outlet area 130 'for dividing a refrigerant mixture on the flow channels 128 in one of the foils 120 of the power supply 110 according to the invention Even distribution of the refrigerant mixture in the inlet region 130 on the flow channels 128 in the film 120, the distribution element 132, as shown, can preferably have a plurality of periodically arranged elevations 136 and depressions 138 located between them. In this case, the elevations 136 can preferably assume the same level as the surface of the film 120, while the depressions 138 can preferably have the same channel depth as the flow channels 128. The distribution elements 132, 132 ′ can advantageously serve, in particular, to prevent a maldistribution of the flow during operation during the distribution of the flow over a plurality of parallel flow channels 128.

FIGS. 4a to 4c each show a schematic representation of a preferred exemplary embodiment of a single-stage device 140 for generating cryogenic temperatures and for transporting electrical energy from an energy source 142 arranged in a warm area 142 of the device 140 to one introduced in a cold area 146 of the device 140 Application 148, which in particular has at least one high-temperature superconductor 150 or a component which comprises at least one high-temperature superconductor 150. While the warm area 142 is preferably set up for ambient temperature and usually maintained at ambient temperature, the cold area 146 is typically at a cryogenic temperature during operation of the device 140. For the terms “ambient temperature” and “cryogenic temperature”, reference is made to the definitions above.

In the warm region 142, a cooler 152 provides a refrigerant mixture which comprises a mixture of at least two components of refrigerants set up for the device 140, at least two of the components having a boiling point that differs from one another. In order to be able to achieve the highest possible efficiency when the refrigerant mixture is cooled from the ambient temperature to the cryogenic temperature, a high-boiling refrigerant mixture is used which comprises both at least one higher-boiling component and at least one lower-boiling component. As mentioned above, the at least one higher-boiling component can preferably be selected from a hydrocarbon and a fluorinated hydrocarbon, while the at least one lower-boiling component can preferably be selected from oxygen, nitrogen, argon, neon, hydrogen and helium. However, other substances are possible.

As shown in FIGS. 4a to 4c, the present device 140 comprises two power supply lines 110, 110% arranged in the cold region 146, as described in particular above with regard to FIGS. 1 to 3c. The introduction of the warm refrigerant mixture the warm area 142 into the cold area 146 takes place at high pressure level by means of a respective supply line 154, 154% each of which opens into a high pressure side 156, 156 'of the power supply lines 110, 110', which are set up as first heat exchangers 158, 158 'at the same time are designed as countercurrent heat exchangers in the exemplary illustration according to FIGS. 4a to 4c. Furthermore, each of the first heat exchangers 158, 158 'has a low-pressure side 160, 160' which is designed to deliver the cold refrigerant mixture to the warm area 142 by means of a discharge line 162, 162 '. The warm refrigerant mixture supplied from the warm region 142 to each high-pressure side 156, 156 ′ thus has a higher temperature compared to the refrigerant mixture provided on each low-pressure side 160, 160 ′ for delivery to the warm region 142. Consequently, the cold refrigerant mixture provided on each low-pressure side 160, 160 'contributes significantly to the cooling of the warm refrigerant mixture supplied on each high-pressure side 156, 156' from the warm area 142, whereby a transfer of thermal energy through the countercurrent heat exchanger can be designed more efficiently, that the refrigerant mixture, which is warm on each high-pressure side 156, 156 ', flows out of the warm region 124 in a direction which is opposite to a direction of the cold refrigerant mixture provided on each low-pressure side 160, 160'.

The refrigerant mixture, which has already been partially cooled on each high-pressure side 156, 156 'in each first heat exchanger 158, 158' and originally supplied from the warm region 142, then passes via a further line 164, 164 'into a respective expansion device 166, 166', which is designed here as an expansion valve. However, an alternative embodiment of the expansion device 166, 166 'as a throttle capillary, diaphragm or sintered element is possible. The expansion device 166, 166 'is also located in the cold area 146 and is set up to cool the refrigerant mixture to the low-pressure level. Here, the expansion device 166, 166 'can preferably be set up to achieve the desired cooling of the refrigerant mixture by means of the Joule-Thomson effect, since the refrigerant mixture has been adapted in such a way that the Joule-Thomson coefficient \ i defined according to equation (1) _{JT of} the refrigerant mixture at the temperature of the cold side 146 of the device 146 has a positive value. The expansion device 166, 166 'thus causes, on the one hand, the reduction of the pressure acting on the refrigerant mixture from the high pressure level to the low pressure level and, on the other hand, the desired further cooling of the refrigerant mixture.

As already mentioned above in connection with FIGS. 1 a and 1 b, the power supply 110 includes the first electrical connection 122 for receiving the electrical connection Energy in the form of a current 1+ from the energy source 144 and the second electrical connection 124 for delivering the electrical energy in the form of the current 1+ to the application 148, which is set up to receive the electrical energy provided in this way. In the preferred embodiment according to FIGS. 4 a to 4 c, the second electrical connection 124 of the power supply 110 facing the application 148 in the cold region 146 is connected in an electrically conductive manner to a high-temperature superconductor 168. In this case, the high-temperature superconductor 168 is advantageously arranged between the second electrical connection 124 of the power supply 110 and the application 148, so that in this way a further transport of the electrical energy from the power supply 110 to the application 148 is made possible with as little loss as possible. The high-temperature superconductor 168 can in particular be designed as a tape or a cable.

In order to finally obtain a closed circuit, the electrical energy is transported in the same way as loss-free as possible in the form of a current I- from the application 148 to the power supply 110 'via an associated high-temperature superconductor 168% that is electrically conductive with that of the application 148 is connected in the cold region 146 facing second electrical connection 124 'of the power supply 110'. Furthermore, the power supply 110 ‘comprises the first electrical connection 122‘, which is set up to output the electrical energy in the form of the current I- from the application 148 via the power supply 110 ‘to the energy source 144.

Compared to the exemplary embodiment according to FIG. 4 a, the exemplary embodiment of the device 140 according to FIG. 4 b has two second heat exchangers 170, 170 ‘, which are each set up to cool the application 148 in the cold area 146. As FIG. 4b shows, the refrigerant mixture, which has already been partially cooled on each high pressure side 156, 156 'in each first heat exchanger 158, 158', reaches the respective second heat exchanger via the further line 164, 164 'and the respective expansion device 166, 166' 170, 170 '.

Compared to the exemplary embodiment according to FIG. 4b, the exemplary embodiment of the device 140 according to FIG. 4c has a single second heat exchanger 170, which is set up to cool the application 148, which is arranged in the cold region 146. For this purpose, the refrigerant mixtures already partially cooled on each high-pressure side 156, 156 'in each first heat exchanger 158, 158' are brought together via the partially common further line 164 and passed via the single expansion device 166 to the single second heat exchanger 170. In an analogous manner, the refrigerant is medium mixture from the single second heat exchanger 170 on both low-pressure sides 160, 160 'of the first heat exchangers 158, 158' and thus fed back to the warm area 142.

Figures 5a and 5b each show a schematic representation of a preferred embodiment in which the respective device 140 for generating cryogenic temperatures and for transporting electrical energy from the energy source 142 arranged in the warm area 142 of the device 140 to that in the cold area 146 of the device 140 introduced application 148 is designed in two stages.

Compared to the exemplary embodiment according to FIG. 4a, the exemplary embodiment of the device 140 according to FIG. 5a has a precooler 172 in the warm area 142, which provides a further high-boiling refrigerant mixture which comprises a mixture of at least two components of refrigerants set up for precooling, with at least two here too of the components have a different boiling point from one another. The introduction of the further refrigerant mixture from the warm area 142 into the cold area 146 takes place at high pressure level by means of a further supply line 174, 174 ', which are each set up in the high-pressure sides 156, 156' of the respective first heat exchangers 158, 158 ' Power supply lines 110, 110 'open. The further refrigerant mixture, which has already been partially cooled as a result, then arrives via a further line 176, 176 ‘in a further expansion device 178, 178‘. The delivery of the cold refrigerant mixture to the warm area 142 takes place via the respective low-pressure side 160, 160 'of the first heat exchanger 158, 158 ‘by means of a respective further discharge line 180, 180‘. Furthermore, the exemplary embodiment of the device 140 according to FIG. 5a, compared to the exemplary embodiment according to FIG ", 110 '" to cool further.

Compared to the exemplary embodiment according to FIG. 5a, the exemplary embodiment of the likewise two-stage device 140 according to FIG. For this purpose, the refrigerant mixture, which has already been partially cooled in each first heat exchanger 158, 158% 158 ", 158 '", reaches the respective second heat exchanger 170, 170' via the further line 164, 164 'and the respective expansion device 166, 166'. List of reference symbols

110, 110 ‘... power supply 144 energy source

112 upper cover plate 146 cold area

114, 114 ‘... nozzle 148 Application

116 lower cover plate 150 high temperature superconductor

118 Stack 152 Cooler

120, 120 'foil 154, 154' supply line 122, 122 'first electrical connection 156, 156' high pressure side 124, 124 'second electrical connection 158, 158' ... first heat exchanger 126, 126 'passage 160, 160' low pressure side 128 flow channel 162, 162 'outlet 130 inlet area 164, 164' further line 130 'outlet area 166, 166' first expansion device

132, 132 ‘distribution element 168, 168‘ high temperature superconductor

134 first flow path 170 second heat exchanger

134 ‘second flow path 172 precooler

134 “third flow path

134 ‘“ fourth flow path

136 Elevation 174, 174 ‘further supply line

138 specialization 176, 176 ’further leadership

140 device 178, 178 ‘further expansion device

142 warm area 180, 180 ‘further dissipation

Claims

1. Power supply (110, 110 '...) for transporting electrical energy from an energy source (144) to an application (148) or from the application (148) to the energy source (144), the energy source (144) in one warm area (142) is arranged and wherein the application (148) is arranged in a cold area (146), wherein the power supply (110, 110 ') is a stack (118) comprising at least two foils (120, 120' .. .), wherein each film (120, 120 '...) comprises an electrically conductive material which is set up to transport the electrical energy, each film (120, 120' ...) each having an electrical connection, which is set up to receive the electrical energy or to deliver the electrical energy, and wherein each film (120, 120 '...) comprises a plurality of flow channels (128) for guiding a fluid flow, the fluid flow being a refrigerant mixture or a gas flow to be cooled or a gas to be liquefied comprising the flow, wherein the foils (120, 120 ', ...) comprised by the stack (118) have a first flow path (134) through the flow channels (128) which is used to receive the fluid flow at high pressure level from the warm area ( 142) is set up, and a second flow path (134 ') through the flow channels (128), which is set up to receive the fluid flow at low pressure level from the cold area (146).

2. Power supply (110, 110 ‘...) according to the preceding claim, wherein the film (120, 120‘ ...) has at least one further flow path (134 ″, 134 ″) selected from

- A third flow path (134 ″) through the flow channels (128), which is set up to receive a vapor phase of the refrigerant mixture at low pressure level from the cold region (146);

- A fourth flow path (134 ") through the flow channels (128), which is set up to receive the gas flow to be cooled or the gas flow to be liquefied from the warm region (142).

3. Power supply (110, 110 '...) according to one of the preceding claims, wherein all flow channels (128) of each film (120, 120' ...) of a stack (118) either for To receive the fluid flow from the warm area (142) or to receive the fluid flow at low pressure level from the cold area (146).

4. Power supply (110, 110 ‘...) according to one of the preceding claims,

- The flow channels (128) of adjacent stacked foils (120, 120 ‘...) in the stack (118) are set up alternately to receive the fluid flow at the high pressure level and to receive the fluid flow at the low pressure level, or

- The flow channels (128) at most two adjacent stacked foils (120 ', 120 ") in the stack (118) for receiving the fluid flow at high pressure level and an adjoining further foil (120, 120"') for receiving of the fluid flow is set up at the low pressure level, or

- wherein the flow channels (128) at most two adjacent stacked foils (120 ', 120 "...) are set up in the stack (118) to receive the fluid flow at the low-pressure level and a further foil (120, 120"' adjoining them) ) is set up to receive the fluid flow at high pressure level.

5. Power supply (110, 110 '...) according to one of the preceding claims, wherein the flow channels (128) are each introduced on one side of each film (120, 120' ...), with adjacent stacked films (120, 120 '...) are introduced into the stack (118) in such a way that openings in the flow channels (128) are arranged facing away from one another.

6. Power supply (110, 110 '...) according to one of the preceding claims, wherein each film (120, 120' ...) has an entry area (130) and an exit area (130 ') for the flow channels (128) , at least the inlet area (130) or the outlet area (130 ') via a distribution element (132, 132' ...) which is used to distribute the fluid flow to the flow channels (128) of the film (120, 120 '...) is furnished, has.

7. Power supply (110, 110 '...) according to one of the preceding claims, wherein at least one side of the stack (118) is provided with a cover plate (112, 116), at least one of the cover plates (112) each having at least one supply line for supplying the fluid flow and a discharge line for discharging the fluid flow.

8. power supply (110, 110 ‘...) according to any one of the preceding claims, wherein the electrically conductive material is selected from copper, aluminum or brass.

9. Device (140) for generating cryogenic temperatures and for transporting electrical energy from an energy source (144) to an application (148) or from the application (148) to the energy source (144), comprising at least one cooling stage which has a warm area (142) and a cold area (146), with a refrigerant mixture set up for the cooling stage and the energy source (144) being provided in the warm area (142), the refrigerant mixture having at least two components with boiling temperatures that differ from one another, the cold area (146) of at least one cooling stage comprises the following:

- At least one power supply (110, 110 ...) according to one of the preceding claims, wherein the at least one power supply (110, 110 ‘...) is set up as a first heat exchanger (158, 158‘ ...) at the same time;

- At least one first expansion device (166, 166 ‘...), which is set up for expansion and cooling of the refrigerant mixture to the low-pressure level; and

- The application (148), which is set up to receive the electrical energy and / or to output the electrical energy.

10. The device (140) according to the preceding claim, further comprising

- A second heat exchanger (170, 170 ‘...) which is set up to cool the application (148).

11. Use of a device (140) according to one of the preceding device claims for cooling and operating high-temperature superconductors (168, 168 ‘) at a temperature of 15 K to 90 K.

12. A method for producing a power supply (110, 110 '...) according to one of the preceding claims relating to the power supply (110, 110' ...), wherein the power supply (110, 110 '...) is used to transport electrical energy from an energy source (144) to an application (148) or from the application (148) to the energy source (144), wherein the energy source (144) is arranged in a warm area (142) and wherein the application (148) placed in a cold area (146) comprising the steps of: a) providing at least two foils (120, 120 '...), each foil (120, 120' ...) comprising an electrically conductive material which is designed to transport electrical energy, each foil (120 , 120 '...) at each end has in each case an electrical connection which is set up to receive electrical energy or to output electrical energy; b) introducing a multiplicity of flow channels (128), which are set up to receive a fluid flow, into the at least two foils (120, 120 '...); c) arranging the at least two foils (120, 120 '...) in the form of a stack (118) and diffusion welding the at least two foils (120, 120' ...), the electrical connection of each foil (120, 120 '...) remains unwelded in the cold area (146).

13. The method according to the preceding claim, wherein the introduction of the plurality of flow channels (128) in the at least two foils (120, 120 ‘...) takes place by means of an etching process or by means of micro-milling.

14. The method according to any one of the preceding method claims, wherein arranging the at least two foils (120, 120 '...) in the form of the stack (118) attaching at least one cover plate (112, 116) to at least one side of the stack (118 ), wherein the diffusion welding of the at least two foils (120, 120 '...) comprises the at least one cover plate (112, 116), the method having the further step: d) introducing at least one nozzle (114, 114' in each case) ...), which is set up to supply and / or discharge the fluid flow, into at least one of the cover plates (112, 116).

15. The method according to any one of the preceding method claims, wherein the method has the further step: e) attaching at least one high-temperature superconductor (168, 168 ') to the electrical connection of the foils (120, 120' ...), which is used for delivery the electrical energy to the application (148) or to receive the electrical energy from the application (148).