WO2015169576A1

WO2015169576A1 - Cooling device for at least two components to be cooled, rail vehicle and method for cooling

Info

Publication number: WO2015169576A1
Application number: PCT/EP2015/058512
Authority: WO
Inventors: Tabea Arndt; Jörn GRUNDMANN; Anne KUHNERT; Peter Kummeth
Original assignee: Siemens Aktiengesellschaft
Priority date: 2014-05-06
Filing date: 2015-04-20
Publication date: 2015-11-12
Also published as: DE102014208437A1

Abstract

The invention relates to a cooling device (19) for at least two components to be cooled, at least one of said components comprising a superconductor, and all components being sequentially cooled by the same cooling medium that is guided in a closed refrigeration circuit (3).

Description

description

Cooling device for at least two components to be cooled, rail vehicle and method of cooling

The invention relates to a cooling device for at least two components to be cooled, at least one of which comprises a superconductor. In addition, the invention comprises a rail vehicle and a method for cooling.

Components of devices comprising a superconductor are often referred to as superconducting components. For example, in electric machines used for driving or as a generator, a superconducting machine is used when superconductors are used inside the stator or, more commonly, the rotor. High-temperature superconductors now allow the use of superconducting technology due to the smaller installation space required in mobile units, such as vehicles, as well as wherever there is less space available due to the design.

An example of such mobile units are rail vehicles, ie rail vehicles, in particular locomotives and power cars, which require efficient drives and small, efficient transformers. Due to their advantages, superconducting and in particular high-temperature superconducting applications such as HTS transformers and HTS motors (high-temperature superconducting machines) are suitable for this purpose. All superconducting components must be cooled to temperatures below their critical temperature for operation so that a cooling system is required for each superconducting component. Other applications that have already demonstrated the benefits of HTS engines are 4MW marine propulsion engines.

Superconducting components are realized in a rail vehicle, in addition to the superconducting machine often a transformer is needed, which is then advantageously realized superconducting. However, in other applications, it may happen that several superconducting components require cooling or, in addition to a superconducting component, other components are present which do not contain superconductors but still require cooling. In all cases it is known to associate each of these components with their own independent cooling system. Then, in the example of the rail vehicle with a superconducting machine as a drive motor and a superconducting transformer, a plurality of compressors with cold heads and a plurality of lines necessary to cool components to the required operating temperature can. The invention is therefore based on the object, on the other hand, improved and in particular space-saving options for cooling components, in particular superconducting components in rail vehicles specify. To solve this problem, it is provided according to the invention in a cooling device of the type mentioned that all components are cooled sequentially by the same in a closed cooling circuit guided cooling medium. It is therefore proposed a combined cooling system, which allows a cascaded cooling of several components by the same cooling medium. Thus, not all components, in particular all superconducting components, have to be cooled separately from each other by separate cooling devices, but a single cooling device with a closed cooling circuit is used, in which the cooling medium initially cools at least one first, in particular superconducting, component , In the already slightly heated state, to be used for cooling other, in particular also superconducting components. In a special embodiment, the cooling medium is evaporated by the cooling of at least one component, whereupon at least one further component with the cold, gaseous Cooling medium is also cooled in this closed cooling circuit. After the finally heated, in particular gaseous cooling medium exits from the last component to be cooled or one of the last component to be cooled heat exchanger exits, it is fed to a cooled by at least one cold head condenser (or more condensers) to cooled again, in particular liquefied to become available again for cooling the components to be cooled.

In particular, the components to be cooled are a superconducting machine, in particular a HTS drive machine, and a superconducting transformer, in particular a HTS transformer, for rail vehicles which are accommodated, for example, in the power train of a train or in a locomotive.

Overall, a large number of advantages results from this embodiment according to the invention. On the one hand, the investment costs for cooling the at least two to be cooled

Components which in particular comprise all superconductors, preferably high-temperature superconductors, are significantly lower, since only one cooling device is required. The required cooling medium cools several components, for example the superconducting prime mover in liquid form and a superconducting transformer and / or a further component as a cold gas, so that substantially less volume of liquid cooling medium, for example expensive neon, is needed to supply the components of the Cool overall system. Accordingly, two storage tanks are not necessary as a buffer volume for gaseous cooling medium, for example neon or nitrogen. Thus, the space required for cooling the components to be cooled is significantly lower. Also by saving at least one other cooling device space and weight is additionally saved. These advantages are particularly important in the context of mobile applications, such as a rail vehicle, extremely important. The cooling medium used is therefore used much more efficiently. One and the same cooling medium cools all components one after the other in a closed cooling circuit. Incidentally, as will be explained in more detail below, the operating parameters of the cooling device can be adapted accordingly in order to match the operation of the cooling device to the operating temperatures of the components to be cooled. For example, an adjustment of the operating pressure (vapor pressure of the gaseous cooling medium) can be made according to the required application.

The present invention makes use of the fact that different operating temperature requirements are frequently imposed by different components to be cooled, for example, different critical temperatures or operating temperatures can be present for superconducting components to be cooled, so that heat loss to one component can result in the use of the cooling medium does not necessarily exclude another component. If one considers the example of the rail vehicle in which a superconducting machine and a superconducting transformer are built, the superconducting machine usually has a rather high magnetic field, which can lower the design operating temperature, so that cooling to a low temperature is necessary here , Consequently, the superconducting machine can first be cooled by liquid cooling medium, in particular with its evaporation, but the gaseous cooling medium can then be used without problems in order to cool the superconducting transformer arranged in a significantly lower magnetic field, the operating temperature of which may be correspondingly higher.

If at least one component having no superconductor is present, it can be provided that it is cooled by the component having at least one superconductor component of the cooling medium. Components that are not superconducting are usually operated at a higher operating temperature, so that they are secondarily protected by the already at least one superconducting component heated cooling medium can be cooled.

However, embodiments are also conceivable, in particular as already explained with regard to the rail vehicle, in which at least two, in particular all, components have superconductors. In this case, it is expedient for the cooling sequence of the superconductor components to be selected as a function of a possible operating temperature based on the boundary conditions of their arrangement and / or their use such that the superconductor components of lower critical temperature or operating temperature are cooled earlier by the cooling medium are considered to be those of higher critical temperature or operating temperature. For example, therefore, the magnetic field in the region of the superconductor and / or the current, in particular the current density, can be evaluated by the superconductor, resulting in certain maximum permissible operating temperatures which are to be undercut for the components during operation. It then goes without saying that it is advisable first to cool the superconducting components which have the lower maximum permissible operating temperature and then those which have a higher maximum permissible operating temperature. It should also be noted in this context that not only the cooling sequence, but also operating parameters of the cooling device can be selected according to the present requirements, in particular the vapor pressure of the gaseous cooling medium. If, for example, a cold head used is operated in this way and its operating temperature, for example by means of a controlled, in particular electrical heater on the condenser, controlled so that the cooling medium, for example neon or nitrogen at an absolute pressure below atmospheric pressure, that is less than about 1 bar , is present in the cooling circuit, so advantageously the available lower cooling temperature can be used to better exploit the superconducting components used, that is to operate in particular with a higher operating current (due to the higher critical current). Alternatively, however, it is also conceivable and may be advantageous to keep the absolute operating pressure (vapor pressure) above the atmospheric pressure, ie above about 1 bar. This ensures that although the temperature of the cooling medium higher, thus the achievable operating current is somewhat lower, especially in cooled by liquid cooling medium components, however, is due to the higher vapor pressure and thus the higher density in the gaseous cooling medium a more effective heat exchange and thus a more effective Cooling of the component favors, which are cooled by the gaseous cooling medium. The heat exchange between the gaseous cooling medium and the component or components to be cooled is increased by a higher gas density and can thus lead to a lower operating temperature of the gas-cooled components.

In summary, by adapting the vapor pressure of the cooling medium in the cooling system, it is thus possible to achieve a skillful utilization of the existing freedoms in the state diagram which satisfies the requirements, and in particular to coordinate the operating temperatures of the components to be cooled. As already mentioned, the cooling device according to the invention can be used particularly advantageously if the components comprise at least one superconductive component of a superconducting machine, in particular a rotor and / or a stator, and / or a superconducting transformer. The superconductors are preferably high-temperature superconductors.

In a further embodiment of the invention, it can be provided that the cooling circuit comprises a supply pipe for liquid cooling medium to a component to be cooled, in particular a rotor and / or stator of a superconducting machine, and an exhaust pipe for gaseous cooling medium on a particular first to be cooled component , Such Embodiment is particularly useful when at least partially the Thermosi- phon effect is used to transport the cooling medium, as then by the aforementioned embodiment, a so-called two-tube thermosiphon is realized Siert. Cooling devices, which after the thermosyphon

Working principle, are used particularly frequently in superconducting machines. In the present case, it is therefore proposed to use separate tubes for the liquid and the gaseous cooling medium, so that a simpler way exists to separate the gaseous cooling medium and in particular to supply it to a further component to be cooled. Therefore, a particularly advantageous embodiment provides that at least one further component is cooled by the gaseous cooling medium, in particular a superconducting transformer.

If the component to be cooled is a rotor of a superconducting machine, it is already known from the prior art to guide the liquid coolant into an interior space of the hollow rotor which acts as an evaporator and thereby cools the rotor and thus the superconductors provided therein. The evaporated cooling medium is correspondingly discharged again in the direction of the condenser, in this case via the exhaust pipe. The two tubes can be suitably carried out concentrically. A gas-tight rotary feedthrough, for example a ferrofluid seal, can be used to allow the tubes to protrude into the interior of the rotor. There have also been proposed solutions in which co-rotating feed tubes are used for cooling medium. An example of possibilities for realizing the cooling of a superconducting machine with superconducting rotor winding can be found in the applicant's DE 10 2007 030 474 AI, although, of course, other concrete configurations with respect to a superconducting machine as a component to be cooled are also conceivable.

Thus, it follows that a particularly advantageous embodiment of the present invention is present when in a mobile unit, in particular a rail vehicle, as Components of a superconducting machine and a superconducting transformer are cooled by a single cooling device, wherein a two-tube thermosyphon is used in which the liquid cooling medium in the corresponding portion of the superconducting machine is coolingly evaporated, after which the cold gaseous cooling medium supplied to the superconducting transformer is further heated there by its cooling effect and then returned to the condenser, where it is re-liquefied and fed to the superconducting machine. Especially in mobile units, the space is limited, so that the described advantages of using a single cooling device pay particular attention; Moreover, due to the special properties of the superconducting machine and of the superconducting transformer, which has a higher critical temperature or operating temperature, such an embodiment can only be realized in the described manner, in which the gaseous, cold cooling medium cools the transformer. As already mentioned, the operating pressure, ie the

Vapor pressure of the gaseous cooling medium to be selected according to the requirements of the components to be cooled. Consequently, the cooling device can expediently also have a vapor pressure regulating device, in particular comprising a heating device, in particular in the region of the condenser or the condensers. Such control options are already known in principle in the prior art and usually include the choice of a suitable operating temperature at the condenser, which can be adjusted by means of a particular electric heater on the condenser so that the vapor pressure remains in a certain desired pressure range. In this way, for example, an operation at a pressure <1 bar can be provided, for example, if components are to be operated with a higher operating current, or even steam pressures above atmospheric pressure are selected, for example, if a more effective heat exchange in gas-cooled Components should be achieved. In addition to the cooling device, the invention also relates to a rail vehicle, in particular a locomotive or a power train of a train, comprising a superconducting machine and a superconducting transformer as components to be cooled and a cooling device of the type according to the invention. As already mentioned, the present invention is particularly useful use such mobile units, in which a space and weight savings is particularly advantageous and profitable. All statements regarding the cooling device according to the invention can be analogously transferred to the rail vehicle according to the invention, so that the advantages mentioned are obtained with this.

Finally, the invention also relates to a method for cooling at least two components to be cooled, at least one of which comprises a superconductor, which is characterized in that a circulating in a closed cooling circuit cooling medium after heating by cooling a component for cooling the at least one another component is used. Also on the inventive method, which describes the cascaded cooling of at least two components to be cooled by a single cooling device, the previous statements can be applied and it can be achieved the advantages mentioned.

As already stated with respect to the cooling device, it is particularly advantageous if, in the case of at least two components to be cooled, with a superconductor, the cooling sequence

and / or the vapor pressure of the cooling medium is selected as a function of a critical temperature or operating temperature which is possible due to the magnetic field in the region of the superconductor and / or the current through the superconductors. It is of course expedient to cool components to be cooled with a lower critical temperature or operating temperature before components with a higher critical temperature or operating temperature. Another set screw for optimizing tion of the overall cooling process represents the vapor pressure after it has been shown to have opposite effects on liquid cooled and gas cooled components. At operating pressures <1 bar, the temperature of the liquid cooling medium is lower, which is liquid-cooled

Components lower operating temperatures (and thus possibly higher operating currents) allowed, while a higher vapor pressure favors the cooling of gas-cooled components.

Accordingly, it is also generally, as stated, advantageous that at least one component is cooled by vaporized on another liquid-cooled component gaseous cooling medium.

Further advantages and details of the present invention will become apparent from the embodiments described below and with reference to the drawing. 1 shows a schematic diagram of a cooling device according to the invention, and FIG

Fig. 2 is a schematic diagram of a rail vehicle according to the invention.

Fig. 1 shows a schematic diagram of an embodiment of a cooling device according to the invention, as it can be used in a rail vehicle, such as a locomotive, the HTS a prime mover, so a superconducting machine, with a rotor 1 with superconducting windings and a superconducting transformer 2, whose windings also consist of a high-temperature superconducting material. In order to cool these two components, the cooling device according to the invention is used, in which a cooling medium, for example neon or nitrogen, is used. The cooling medium circulates in a cooling system formed from tubes. circuit 3 and is transported by the thermosiphon effect. In the present example, the cold head 4 and the condenser 5 to convert gaseous cooling medium by condensation back to liquid cooling medium, arranged higher than the evaporator, which is in the present case formed by an inner space 6 of the hollow rotor 1 of the superconducting machine. Of course, more than one cold head 4 and / or more than one condenser 5 can be provided, as is basically known in the prior art. After the gaseous cooling medium has been liquefied in the condenser 5, it is guided via a corresponding line 7 for liquid cooling medium to the rotor 1 as the component to be cooled first. The line 7 terminates in a feed tube 8, around which concentrically extends a discharge pipe 9 for gaseous cooling medium. The supply pipe 8 and the discharge pipe 9 are fixed relative to the rotor 1 and are therefore guided through a rotary leadthrough 10, for example a ferrofluid seal, into the interior 6. Thus, there is a total of a two-pipe thermosiphon, in the flow and return of the liquid or gaseous cooling medium, at least in partial areas, here in the region of the tubes 8, 9, run separately.

More concrete embodiments for cooling rotors 1 of superconducting machines are already known in the prior art, reference being made, by way of example only, to the already mentioned DE 10 2007 030 474 A1.

In the rotor 1, the liquid cooling medium evaporates and thus cools the rotor 1 and the superconductor material located on or in the rotor 1, not shown here.

The cold, gaseous cooling medium, thus, for example

Neon gas or nitrogen gas, leaves the rotor 1 via the discharge pipe 9 and is guided via a line 11 for gaseous cooling medium to the HTS transformer 2 as another component to be cooled. As shown schematically in FIG. 1, in the present case the entire transformer 2 is arranged within a cryostat 12, that is to say that in the present exemplary embodiment the iron core 13 and the superconducting windings 14 are equally flowed around by the gaseous cooling medium.

Alternatively, embodiments are also conceivable in which a separate cryostat, for example made of plastic, is formed for each winding, so that only these have to be cooled.

After the gaseous cooling medium has flowed through the superconducting transformer 2, it is again supplied via a connecting further line 15 to the condenser 5, so that the circuit is closed.

It should be noted that, of course, in addition to the superconducting transformer 2 also other components that need not necessarily be superconducting, can be cooled by the gaseous cooling medium if necessary.

In the present case, first the rotor 1 of the superconducting machine is cooled, since there is a lower maximum permissible operating temperature due to the high magnetic fields. This problem is in the field of superconducting

Transformer 2 is not given, so that the gaseous cooling medium is sufficient to sufficiently cool this component higher maximum permissible operating temperature. In this case, the vapor pressure of the gaseous cooling medium represents a further optimization variable which can be set, for example, via the operating temperature of the cold head 4 / condenser 5, in particular to a specific desired value, for which purpose a vapor pressure control device with an electric heater 16 is used. If a supercooled operation of the cooling device is selected, a lower temperature for the liquid cooling medium is possible, so that the rotor and its superconductor on a lower temperature can be maintained, which may allow, for example, larger operating currents. However, then the cooling capacity is in the range of superconducting

Transformers 2 to evaluate something worse. However, if a vapor pressure is chosen that is higher than the atmospheric one

Pressure is the cooling effect due to the higher temperature of the liquid cooling medium in the region of the rotor 1 to classify as worse, however, the high vapor pressure promotes the heat exchange in the region of the superconducting transformer 2, which is therefore given a better cooling efficiency. The concrete choice of the vapor pressure of the gaseous cooling medium is therefore mainly dependent on the requirements and the specific design and represents an optimization variable for the operation of the cooling system.

Fig. 2 shows schematically a railway vehicle according to the invention 17. This has, as mentioned, the superconducting machine 18 with the rotor 1 and the superconducting transformer 2. Both components are cooled by the common cooling device 19 according to the invention, as was explained in FIG.

Although the invention has been further illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Claims

claims

1. Cooling device (19) for at least two components to be cooled, at least one of which comprises a superconductor, characterized in that all components are cooled sequentially by the same in a closed cooling circuit (3) guided cooling medium.

2. The method according to claim 1, characterized in that at least one non-superconducting component is present, which is cooled by the at least one superconductor having component of the cooling medium.

3. Cooling device according to claim 1 or 2, characterized in that at least two, in particular all, components have superconductors.

4. Cooling device according to claim 3, characterized in that the cooling order of the superconducting components depending on a there due to the boundary conditions of their

Arrangement and / or their possible maximum operating temperature is selected so that the superconducting components lower maximum permissible operating temperature are cooled earlier by the cooling medium than those higher maximum permissible operating temperature.

5. Cooling device according to one of the preceding claims, characterized in that the components comprise at least one superconducting portion of a superconducting machine (18), in particular a rotor (1) and / or a stator, and / or a superconducting transformer (2).

6. Cooling device according to one of the preceding claims, characterized in that the cooling circuit (3) on a particular first to be cooled component a supply pipe (8) for liquid cooling medium to a component to be cooled, in particular a rotor (1) and / or Stator one Superconducting machine (18), and a discharge pipe (9) for gaseous cooling medium.

7. Cooling device according to claim 6, characterized in that at least one further component by the gaseous

Cooling medium is cooled, in particular a superconducting transformer (2).

8. Cooling device according to one of the preceding claims, characterized in that for the transport of the cooling medium, at least partially the thermosiphon effect is used.

9. Cooling device according to one of the preceding claims, characterized in that a

Vapor pressure regulating device, in particular comprising a heating device (16), in particular in the range of one or more condensers (5), is provided.

10. Rail vehicle (17), comprising a superconducting machine (18) and a superconducting transformer (2) as components to be cooled and a cooling device (19) according to one of the preceding claims.

11. A method for cooling at least two components to be cooled, at least one of which comprises a superconductor, characterized in that a circulating in a closed cooling circuit (3) cooling medium used after heating by cooling a component for cooling the at least one further component becomes.

12. The method according to claim 11, characterized in that at least two components to be cooled with a superconductor, the cooling order and / or the vapor pressure of the cooling medium as a function of a due to the magnetic field in the region of the superconductor and / or the current through the Superconductor maximum operating temperature is selected.

13. The method according to claim 11 or 12, characterized in that at least one component is cooled by vaporized at another liquid-cooled component gaseous cooling medium.