EP4244549A1

EP4244549A1 - Heat exchanger and refrigerant circuit

Info

Publication number: EP4244549A1
Application number: EP21810302.6A
Authority: EP
Inventors: Andreas Wagner; Thomas Rieger; Philipp JEHS
Original assignee: CTS Clima Temperatur Systeme GmbH
Current assignee: CTS Clima Temperatur Systeme GmbH
Priority date: 2020-11-13
Filing date: 2021-11-08
Publication date: 2023-09-20
Also published as: DE102020130061A1; WO2022101140A1

Abstract

The invention relates to a heat exchanger, comprising: - a refrigerant distributor located at the input side of the heat exchanger; - at least one nozzle element which extends from the refrigerant distributor and delimits a mass flow of the refrigerant; - at least one heat exchanger channel which is attached to the at least one nozzle element and extends in a heat exchanger body; and - a refrigerant collector, which is attached to the at least one heat exchanger channel on the side thereof that is opposite the nozzle element, and which is located at the output side of the heat exchanger.

Description

HEAT EXCHANGER AND REFRIGERANT CIRCUIT

The invention relates to a heat exchanger for generating temperatures below a temperature of approximately 223 K.

In connection with this application, the statement: a temperature of approximately 223 K is to be understood as a temperature in the range from 220 K to 230 K, preferably 220 K to 225 K.

In order to be able to use a refrigerant - in particular carbon dioxide - which tends to form a solid phase at these temperatures, which then converts to the gaseous phase by sublimation, there is the problem that blockages can occur in the heat exchanger due to the solid phase that forms.

The invention is therefore based on the object of creating a heat exchanger in which problems caused by sublimating refrigerants are avoided as far as possible.

According to the invention, this object is achieved by a heat exchanger which has a refrigerant distributor arranged on the inlet side of the heat exchanger, at least one nozzle element running from the refrigerant distributor and limiting a mass flow of the refrigerant, at least one heat exchanger channel which is connected to the at least one nozzle element and which in turn runs in a heat exchanger body, and a refrigerant collector arranged on the output side of the heat exchanger and adjoining the at least one heat exchanger channel on its side opposite the nozzle element. The advantage of the solution according to the invention can be seen in the fact that the mass flow limitation required for the formation of a solid phase of the refrigerant takes place through the nozzle element immediately before entry into the heat exchanger channel, so that there is the possibility of the formation of the solid phase of the refrigerant as possible before entry into the heat exchanger channel and then in the heat exchanger channel, due to the expansion following the nozzle element, essentially only allowing a formation of solid and gaseous phases to take place, with the solid phase and the gaseous phase of the refrigerant in the course of the heat exchanger channel through sublimation of heat record, tape.

Thus, with the solution according to the invention, the formation of a solid phase and thus the problem of blockages due to the formation of the solid phase of the refrigerant can essentially be avoided both in the refrigerant distributor and in the nozzle element.

In particular, one advantageous solution provides that the nozzle element limiting the mass flow of the refrigerant has a cross-sectional area which, in relation to a subsequent heat exchanger channel supplied with refrigerant, is at most 0.05 mm ² or less, preferably at most 0.01 mm ² or less , and more preferably at most 0.005 mm ² or less.

If several nozzle elements carry refrigerant to a heat exchanger channel, the maximum cross-sectional areas should be made even smaller by a factor corresponding to the number of nozzle elements.

If a nozzle element leads refrigerant to several heat exchanger channels, the maximum cross-sectional areas must be increased by a factor corresponding to the number of heat exchanger channels. With regard to the design of the heat exchanger channels, it is preferably provided that they have a cross-sectional area of less than 8 mm ² , preferably 4 mm ² and even better 1.5 mm ² in order to obtain optimum heat transfer, particularly with the sublimating refrigerant.

In principle, any sublimating refrigerant is conceivable as the refrigerant. In particular, carbon dioxide is provided as a refrigerant within the scope of this invention, to which additives, for example hydrocarbons, can also be added if necessary.

With regard to the design of the heat exchanger body, no further details have so far been given.

An advantageous solution provides that the heat exchanger body is designed to enclose the at least one heat exchanger channel on the peripheral side.

In the simplest case, the heat exchanger body is designed as a tubular body.

For example, a heat exchanger channel can run in the heat exchanger body.

Another possibility provides for a multiplicity of heat exchanger channels to run in the heat exchanger body.

In order to achieve the best possible heat transfer to the solid phase of the refrigerant also in the heat exchanger channels, it is preferably provided that the at least one heat exchanger channel has at least one flow deflection area. Such a flow deflection area serves to prevent the solid phase of the refrigerant from settling in the heat exchanger channel by changing or varying the flow conditions, for example by generating turbulence.

It is expediently provided that the flow deflection area brings about a flow deflection at an angle of at least 30° with respect to a rectilinear direction of flow propagation.

It is even better if the flow deflection region effects a flow deflection at an angle of at least 40° with respect to a straight flow propagation.

It is advantageous if the at least one heat exchanger channel has flow deflection areas that connect channel sections running at an angle to one another.

It is particularly favorable if the at least one heat exchanger channel has at least one curved flow deflection area, since this makes it possible to change the flow conditions to a sufficiently large extent.

For example, it is provided here that the at least one curved flow deflection area has a radius of curvature that is at most 40 times the mean diameter of the heat exchanger channel.

It is particularly advantageous if a plurality of flow deflection areas are arranged one after the other in the respective heat exchanger channel, so that the flow conditions are constantly changed in order to prevent the solid phase of the refrigerant from settling along the heat exchanger channel. With regard to the design of the respective heat exchanger channel, no further details have been given so far.

An advantageous embodiment provides that the respective heat exchanger channel extends between a first end area associated with it and formed by the heat exchanger body and connected to the refrigerant distributor and a second end area connected to the refrigerant collector.

With regard to the connection of the heat exchanger body to the refrigerant distributor, no further details have been given so far.

An advantageous solution provides that the first end area of the heat exchanger is arranged such that it engages in the coolant distributor.

This can be realized, for example, by the first end region engaging in a receptacle of the refrigerant distributor, the receptacle receiving and in particular closing the first end region.

In this case, the receptacle can be arranged, in particular formed, on the refrigerant distributor.

A particularly advantageous solution provides for the receptacle to be arranged on a wall of the refrigerant distributor and, in particular, to be formed into the wall by machining it.

In order to connect the receptacle to the heat exchanger body, an expedient solution provides that the receptacle accommodates an end wall area of the heat exchanger body.

In particular, it is provided that the end wall area of the heat exchanger body rests against a base of the receptacle. Furthermore, it is preferably provided that the receptacle encompasses the heat exchanger body in the area of its outer contour at least in a peripheral segment, in particular completely.

With regard to the arrangement of the nozzle element in this exemplary embodiment, no further details were given either.

An advantageous solution provides that the nozzle element, in particular the nozzle channel, extends from a region of the receptacle adjoining the heat exchanger channel to the interior of the refrigerant distributor.

As an alternative to the provision of a receptacle, it is provided in a further advantageous embodiment that the first end region of the heat exchanger body extends into an interior space of the coolant distributor and is in particular arranged in it.

In particular, the heat exchanger channel is closed at the first end area by an embossing of at least one wall area of the heat exchanger body, so that the heat exchanger channel does not open directly into the refrigerant distributor, but instead refrigerant is supplied from the refrigerant distributor via the nozzle element.

It is particularly favorable if the respective heat exchanger channel is closed at the first end area by an embossing of at least one wall area of the heat exchanger body.

The embossing is expediently carried out in such a way that the at least one wall area of the heat exchanger body deformed by the embossing lies within an outer contour of the heat exchanger body in order to be able to easily establish a connection between the refrigerant distributor and the heat exchanger body in the area of the outer contour that is unchanged by such an embossing. In one embodiment, the embossing of the wall area of the heat exchanger body takes place as a one-sided embossing with partial preservation of an outer contour of the heat exchanger body opposite this wall area.

Another solution provides that the embossing is formed as a multi-sided embossing of a plurality of wall areas, in particular two wall areas lying opposite one another, of the heat exchanger body.

Even with such a multi-sided embossing of wall areas of the heat exchanger body, it is preferably provided that this lies within an outer contour of the heat exchanger body.

With regard to the formation of the shape of the nozzle element, no further details have so far been given.

For example, the nozzle element could be designed as a gap which limits the mass flow of the refrigerant.

An advantageous solution provides that the nozzle element is designed as a nozzle channel.

In principle, the nozzle element could be arranged outside of the end area of the heat exchanger channel.

An advantageous solution provides that at least one nozzle element for supplying refrigerant to the respective heat exchanger channel is arranged on the first end area, so that the end area is also used to form the nozzle element. In this case, there is in particular the possibility that the nozzle element is incorporated into the end area, for example this can take place before or after the embossing in the end area.

Advantageously, the nozzle element can be incorporated by laser processing.

Another advantageous solution provides that the nozzle element is arranged in the area of a wall area deformed by the embossing.

A further advantageous solution provides that the nozzle element is incorporated into an end wall area formed by the embossing.

Another advantageous solution provides that the nozzle element is formed by a nozzle channel shaped body against which the at least one wall area is embossed, with the nozzle channel having the shape specified by the nozzle channel shaped body after the removal of the nozzle channel shaped body after embossing.

Alternatively or additionally, the object mentioned at the outset is achieved according to the invention in that a further advantageous solution provides for several heat exchanger channels to lie next to one another in the heat exchanger body, for example in a plane in which the heat exchanger body extends in the form of a plate.

A plate heat exchanger can thus be produced in a simple manner.

In particular, this is possible in that a plurality of heat exchanger bodies are arranged one above the other in a stacking direction with extension planes parallel to one another. Provision is preferably made here for the plurality of heat exchanger bodies to be connected to a refrigerant distributor which extends in the stacking direction.

In principle, it would be conceivable to also produce closed end regions of the heat exchanger channels in a heat exchanger body of this type.

However, it is particularly advantageous with this form of heat exchanger if a nozzle element, in particular a nozzle channel, for feeding refrigerant into the respective heat exchanger channel is arranged in a wall region of the refrigerant distributor, which is adjoined by at least one heat exchanger channel of the heat exchanger body.

In this case, it is further provided that the heat exchanger channels connect to the nozzle elements with their first end area and open into the refrigerant collector with their second end area.

In this case, it is also preferable that the refrigerant collector extends in the stacking direction.

Alternatively or additionally, the object mentioned at the beginning is achieved in that in a further advantageous embodiment of a heat exchanger according to the invention it is provided that the heat exchanger channels run between an inner body enclosing a channel for heat-emitting medium and an outer body enclosing the inner body on its side opposite the heat-emitting medium and which is arranged in the area of a first end side of the inner body and the outer body of the refrigerant distributor and is arranged in the area of a second end side of the inner body and the outer body of the refrigerant collector opposite the first end side. In particular, the nozzle elements, e.g. designed as nozzle ducts, can be arranged in a nozzle element carrier located between the inner body and the outer body, wherein the nozzle element carrier can be embodied, for example, as a distribution ring and with at least one nozzle element, in particular a nozzle duct, opening into one of the heat exchanger ducts.

As an alternative to this, however, it is also conceivable with such a heat exchanger that a nozzle element that limits the mass flow of the refrigerant is arranged in the refrigerant distributor and supplies refrigerant to all of the heat exchanger channels.

This means that in this case the nozzle element has a sufficiently large cross section so that it can act to limit the mass flow for the total number of heat exchanger channels.

Such a nozzle element can be formed, for example, by an annular gap, with the annular gap preferably being formed by two concentric, for example conical, surfaces that can be adjusted relative to one another for setting the annular gap.

In all of the exemplary embodiments, it is preferably provided that the heat-emitting medium supplies heat to the refrigerant in the respective heat-exchanger channel through the respective heat-exchanger body.

Furthermore, it is preferably provided that the at least one heat exchanger body is in direct contact with the heat-exchanging medium in order to ensure optimal heat conduction. Furthermore, to avoid evaporation processes in the refrigerant distributor, it is preferably provided that the heat exchanger in the area of the refrigerant distributor is provided with thermal insulation that encloses it in particular, so that the refrigerant is not cooled to such an extent that it is at least partially converted into a solid before it enters the nozzle element phase can pass.

In addition, the invention relates to a refrigerant circuit, comprising a refrigerant compressor, a heat exchanger extracting heat from the compressed refrigerant and a heat-absorbing heat exchanger fed with the compressed refrigerant, which heat exchanger is designed according to one of the preceding features.

Furthermore, it is preferably provided in this case that the refrigerant supplied to the refrigerant distributor in the refrigerant circuit during operation thereof has a pressure above a triple point of the refrigerant and enters the refrigerant distributor with this pressure.

Furthermore, in such a refrigerant circuit, it is provided that when it is in operation, the pressure of the refrigerant in the heat exchanger channels is below the triple point of the refrigerant and that the refrigerant collector is connected to a suction side of the refrigerant compressor and is kept at this pressure by the refrigerant compressor.

Furthermore, it is preferably provided during the operation of the refrigerant circuit according to the invention that refrigerant is fed into the refrigerant distributor in a supercritical state of the latter.

As an alternative to this, however, it is also conceivable that, during operation of the refrigerant circuit, refrigerant with a liquid phase and a gaseous phase is supplied to the refrigerant distributor. A further embodiment of the solution according to the invention provides that when the refrigerant circuit is in operation, refrigerant in the liquid phase is supplied to the refrigerant distributor.

In order to achieve the lowest possible temperatures with the heat-absorbing heat exchanger according to the invention, the refrigerant circuit according to the invention provides for the refrigerant in the heat exchanger channels to be present at a pressure below the pressure of the triple point of the refrigerant during operation of the refrigerant circuit.

Such a pressure has the consequence that part of the refrigerant changes into the solid phase and another part of the refrigerant into the gas phase and that the refrigerant present in the solid phase then also changes into the gas phase by sublimation.

With regard to the nozzle element, no further details have been given in connection with the previous description either.

In particular, it is advantageous if the nozzle element is dimensioned in such a way that there is essentially no expansion of the refrigerant to a pressure below the triple point of the same during operation of the refrigerant circuit, so that the refrigerant only has the opportunity in the heat exchanger channels to get into the solid To pass phase and then to sublimate.

Furthermore, the invention relates to a temperature testing system, in which a refrigerant circuit is provided according to one of the above features and in which the heat-absorbing heat exchanger interacts with a medium acting on a test object, which is arranged, for example, in a test chamber of the testing system, so that in the test chamber allow the desired low temperatures to be generated. In a further embodiment of the temperature testing system according to the invention, it is preferably provided that the refrigerant circuit supplies compressed refrigerant to a second heat exchanger, in which it evaporates at a pressure which is above the pressure of the triple point of the refrigerant.

Such a second heat exchanger offers the advantage that, due to its higher efficiency, the medium in the test chamber and thus also the test object can initially be cooled with it, and only then when temperatures below approximately 223° K are required, the first heat exchanger for use comes.

The temperature testing system according to the invention can thus be operated with improved efficiency.

In addition, the invention relates to a method for operating a refrigerant circuit and a temperature testing system.

The above description of solutions according to the invention thus includes in particular the various feature combinations defined by the following numbered embodiments:

1. Heat exchanger (30), comprising a refrigerant distributor arranged on the inlet side of the heat exchanger, at least one nozzle element (34, 146) running from the refrigerant distributor (32) and limiting a mass flow of the refrigerant, at least one nozzle element (34, 146) attached to the at least one nozzle element adjoining heat exchanger channel (36), which in turn runs in a heat exchanger body (40), and a refrigerant collector (38) arranged on the outlet side of the heat exchanger (30) and adjoining the at least one heat exchanger channel (36) on its side opposite the nozzle element (34, 146) . 2. Heat exchanger according to embodiment 1, wherein the heat exchanger body (40) is designed to enclose the at least one heat exchanger channel (36) on the peripheral side.

3. Heat exchanger according to embodiment 1 or 2, wherein the heat exchanger body (40) is designed as a tubular body (50).

4. Heat exchanger according to one of the preceding embodiments, wherein a heat exchanger channel (36) runs in the heat exchanger body (40).

5. Heat exchanger according to one of embodiments 1 to 3, wherein a plurality of heat exchanger channels (36) runs in the heat exchanger body (40).

6. Heat exchanger according to one of the preceding embodiments, wherein the at least one heat exchanger channel (36) has at least one flow deflection area (92).

7. The heat exchanger according to embodiment 6, wherein each flow deflection area (92) effects a flow deflection at an angle of at least 20° with respect to a rectilinear direction of flow propagation.

8. The heat exchanger according to embodiment 7, wherein the respective flow deflection region (92) brings about a flow deflection at an angle of at least 40° with respect to a rectilinear direction of flow propagation.

9. Heat exchanger according to one of the embodiments 6 to 8, wherein the at least one heat exchanger channel (36) has flow deflection areas (92) which connect channel sections (94) running at an angle to one another. 10. Heat exchanger according to one of embodiments 6 to 9, wherein the at least one heat exchanger channel (36) has at least one flow deflection area (92') running in a curved manner.

11. The heat exchanger according to embodiment 10, wherein the at least one curved flow deflection area (92') has a radius of curvature (R.) which is at most 40 times an average diameter of the heat exchanger channel (36).

12. Heat exchanger according to embodiment 10 or 11, wherein several flow deflection areas (92) are arranged in succession in the respective heat exchanger channel (36).

13. The heat exchanger according to one of the preceding embodiments, wherein the respective heat exchanger channel (36) is connected between a first end region (42) assigned to it and formed by the heat exchanger body (40) and connected to the coolant distributor (32) and a first end region (42) connected to the coolant collector (38). second end region (44).

14. The heat exchanger according to embodiment 13, wherein the first end region (42) of the heat exchanger body (40) is arranged such that it engages in the coolant distributor (32).

15. Heat exchanger according to embodiment 13 or 14, wherein the first end region (42) engages in a receptacle (35) of the coolant distributor (32).

16. Heat exchanger according to embodiment 15, wherein the receptacle (35) is arranged on a wall (33) of the refrigerant distributor (32).

17. Heat exchanger according to embodiment 15 or 16, wherein the receptacle (35) accommodates an end wall area (64) of the heat exchanger body (40). 18. Heat exchanger according to one of embodiments 15 to 17, wherein the receptacle (35) encompasses the heat exchanger body (40) in the area of its outer contour (52) at least in the area of a peripheral segment.

19. Heat exchanger according to one of embodiments 15 to 18, wherein the nozzle element (34) extends from an area of the receptacle (35) adjoining the heat exchanger channel (36) to the interior (46) of the refrigerant distributor (32).

20. Heat exchanger according to one of the preceding embodiments, wherein the first end region (42) of the heat exchanger body (40) extends into an interior space (46) of the refrigerant distributor (32).

21. Heat exchanger according to embodiment 20, wherein the respective heat exchanger channel (36) is closed at the first end area by an embossing of at least one wall area (56) of the heat exchanger body (40).

22. Heat exchanger according to embodiment 21, wherein the at least one wall area (56) of the heat exchanger body (40) formed by the embossing lies within an outer contour (52) of the heat exchanger body (50).

23. Heat exchanger according to embodiment 21 or 22, wherein the embossing of the wall area (56) of the heat exchanger body (40) is designed as a one-sided embossing with partial preservation of an opposite outer contour (52) of the heat exchanger body (50).

24. Heat exchanger according to one of embodiments 21 to 23, wherein the embossing is designed as a multi-sided embossing of wall regions (56a, 56b) of the heat exchanger body (50'). 25. Heat exchanger according to one of the preceding embodiments, wherein the nozzle element is designed as a nozzle channel (34).

26. Heat exchanger according to one of embodiments 19 to 25, wherein at least one nozzle element (40, 146) for supplying refrigerant to the respective heat exchanger channel (36) is arranged on the first end region (42).

27. Heat exchanger according to embodiment 26, wherein the nozzle element (34) is incorporated into the end area (42).

28. Heat exchanger according to one of the embodiments 21 to 27, wherein the nozzle element (34) is arranged in the area of a wall area (56, 64) deformed by the embossing.

29. Heat exchanger according to embodiment 28, wherein the nozzle element (34) is incorporated into an end wall area (64) formed by the embossing.

30. Heat exchanger according to embodiment 28, wherein the nozzle element (34) is formed by a nozzle channel shaped body (72), against which the embossing of the at least one wall region (56) takes place.

31. Heat exchanger according to the preamble of embodiment 1 or according to one of the preceding embodiments, wherein a plurality of heat exchanger channels (36) lie next to the heat exchanger body (40') in a plane in which the heat exchanger body (40') extends in the form of a plate.

32. The heat exchanger according to embodiment 31, wherein a plurality of heat exchanger bodies (40') are arranged one above the other in a stacking direction (102) with extension planes parallel to one another. 33. Heat exchanger according to embodiment 31 or 32, wherein the plurality of heat exchanger bodies (40') are connected to a refrigerant distributor (32') extending in the stacking direction (102).

34. Heat exchanger according to embodiment 33, wherein in a wall area of the refrigerant distributor (32), to which at least one heat exchanger channel (36) of the heat exchanger body (40') adjoins, a nozzle element (34) for supplying refrigerant into the respective heat exchanger channel (36) is arranged.

35. Heat exchanger according to one of the preceding embodiments, wherein the heat exchanger channels (36) connect to the nozzle elements (34) with their first end areas (42) and open into the refrigerant collector (38') with their second end areas (44').

36. The heat exchanger according to embodiment 35, wherein the refrigerant collector (38') extends in the stacking direction (102).

37. Heat exchanger according to the preamble of embodiment 1 or according to one of the preceding embodiments, wherein the heat exchanger channels (36) between an inner body (122) enclosing a channel for heat-emitting medium and an outer body enclosing the inner body (122) on its side opposite the heat-emitting medium (124) and that the refrigerant distributor (32'') is arranged in the area of a first end side of the inner body (122) and the outer body (124) and in the area of a second end side of the inner body (122) and the outer body opposite the first end side (124) the coolant collector (38''") is arranged. 38. Heat exchanger according to embodiment 37, wherein the nozzle elements (34) are arranged in a nozzle element carrier (128) located between the inner body (122) and the outer body (124) and that in each case at least one nozzle element (34) is inserted into one of the heat exchanger channels (36) flows.

39. Heat exchanger according to embodiment 37, wherein a nozzle element (146) limiting the mass flow of the refrigerant is arranged in the refrigerant distributor (32″″) and supplies refrigerant to all heat exchanger channels (36).

40. Heat exchanger according to one of the preceding embodiments, wherein a heat-emitting medium supplies heat to the coolant in the respective heat-exchanger channel (36) through the respective heat-exchanger body (40).

41. Heat exchanger according to embodiment 40, wherein the at least one heat exchanger body (40) is in direct contact with the heat-exchanging medium.

42. The heat exchanger according to one of the preceding embodiments, wherein the heat exchanger (30) is provided in the area of the refrigerant distributor (32) with thermal insulation (86) enclosing it in particular.

43. Refrigerant circuit (10) comprising a refrigerant compressor (12), a heat exchanger (18) extracting heat from the compressed refrigerant, and a heat-absorbing heat exchanger (30) fed with the compressed refrigerant, which is designed according to one of the preceding embodiments. 44. Refrigerant circuit according to embodiment 43, wherein the refrigerant supplied to the refrigerant distributor (32) in the refrigerant circuit (10) has a pressure above a triple point of the refrigerant and enters the refrigerant distributor (32) with it.

45. Refrigerant circuit according to embodiment 43 or 44, wherein the pressure of the refrigerant in the heat exchanger channels (36) is below the triple point of the refrigerant and the refrigerant collector (38) is connected to a suction side (14) of the refrigerant compressor (12).

46. Refrigerant circuit according to embodiment 43 to 45, wherein in the refrigerant circuit (10), refrigerant is supplied into the refrigerant distributor (32) in a supercritical state thereof.

47. Refrigerant circuit according to one of the embodiments 43 to 46, wherein in the refrigerant circuit (10) a supply of refrigerant with a liquid and a gaseous phase takes place in the refrigerant distributor (32).

48. Refrigerant circuit according to one of the embodiments 43 to 47, wherein in the refrigerant circuit (10) a supply of refrigerant in the liquid phase takes place in the refrigerant distributor (32).

49. Refrigerant circuit according to one of embodiments 43 to 48, wherein the refrigerant in the heat exchanger channels (36) is at a pressure corresponding to a sublimation pressure of the refrigerant.

50. Refrigerant circuit according to one of the embodiments 43 to 49, wherein the nozzle element (34) is dimensioned such that there is no expansion of the refrigerant at a pressure below the triple point thereof. 51. Temperature testing system, wherein this has a refrigerant circuit (10) according to one of the embodiments 43 to 50, and that the heat-absorbing first heat exchanger (30) according to one of the embodiments 1 to 42 with a medium (214) acting on a test object, in particular arranged in a test chamber (210).

52. Temperature testing system according to embodiment 51, wherein the refrigerant circuit supplies compressed refrigerant to a second heat exchanger (230), in which this refrigerant evaporates at a pressure which is above the pressure of the triple point of the refrigerant.

53. A method for operating a refrigerant circuit (10) comprising a refrigerant compressor (12), a heat exchanger (18) extracting heat from the compressed refrigerant and a heat-absorbing heat exchanger (30) fed with the compressed refrigerant, which is designed according to one of the preceding embodiments, wherein in the refrigerant circuit (10) the refrigerant is supplied to the refrigerant distributor (32) at a pressure above a triple point of the refrigerant.

54. The method according to embodiment 53, wherein a pressure of the refrigerant which is below the triple point of the refrigerant is maintained in the heat exchanger channels (36).

55. The method according to embodiment 53 or 54, wherein in the refrigerant circuit (10), the refrigerant is supplied to the refrigerant distributor (32) in a supercritical state thereof.

56. The method according to any one of embodiments 53 to 55, wherein in the refrigerant circuit (10) the refrigerant is supplied with a liquid and a gaseous phase to the refrigerant distributor (32). 57. The method according to any one of embodiments 53 to 56, wherein in the refrigerant circuit (10) the refrigerant is supplied in the liquid phase to the refrigerant distributor (32).

58. The method according to any one of embodiments 53 to 57, wherein the refrigerant in the heat exchanger channels (36) is kept at a pressure corresponding to a sublimation pressure of the refrigerant.

59. The method according to any one of embodiments 53 to 58, wherein the refrigerant is fed to and guided in the nozzle element (34) at such a pressure that there is no expansion of the refrigerant at a pressure below the triple point thereof.

60. Method for operating a temperature testing system, which has a refrigerant circuit (10') according to one of the embodiments 43 to 50, and a heat-absorbing first heat exchanger (30) according to one of the embodiments 1 to 42, which is connected to a medium (214), in particular in a test chamber (210) thereof, and in which the refrigerant circuit (10') is operated according to a method according to one of the embodiments 53 to 59.

61. Method for operating a temperature testing system according to embodiment 60, wherein compressed refrigerant from the refrigerant circuit (10') is fed to a second heat exchanger (230) that interacts with the medium (214) and is evaporated therein at a pressure which, in particular, is above the pressure of the triple point of the refrigerant.

62. The method according to embodiment 61, wherein either the first heat exchanger (30) or the second heat exchanger (230) is fed with refrigerant from the refrigerant circuit (10'). 63. The method according to embodiment 62, wherein the first heat exchanger (30) or the second heat exchanger (230) are fed with refrigerant by a controller depending on the temperature of the medium (214).

Further features and advantages of the invention are the subject of the following description and the graphic representation of some exemplary embodiments.

Show in the drawing:

1 shows a schematic representation of a first embodiment of a refrigerant circuit according to the invention;

2 shows a first exemplary embodiment of a heat exchanger according to the invention;

3 shows a schematic representation of a first end region of a heat exchanger body designed as a tubular body, wherein

Fig. 3a is a plan view of the end portion and

Figure 3b shows a longitudinal section through the end portion;

4 shows a representation of a closure of the heat exchanger channel of the tubular body in the first end area, wherein

Figure 4a is a front plan view;

Fig. 4b is a longitudinal section and Fig. 4c shows the final shape of a closure of the tubular body achieved by stamping;

5 shows a schematic representation similar to FIG. 4 of the production of a nozzle channel by inserting a nozzle channel shaped body during embossing and removing the same after embossing

5a shows the embossing with the nozzle channel shaped body in a plan view from the front

5b shows the embossing with the nozzle channel shaped body in longitudinal section

5c shows the end shape of the nozzle channel after removal of the nozzle channel shaped body;

6 an introduction of a nozzle channel into an end wall area of the end area produced by embossing

6a shows the embossing in a plan view from the front

6b shows the embossing in a longitudinal section when the nozzle channel is incorporated

6c shows the incorporated nozzle channel;

FIG. 7 shows a closure of a heat exchanger channel by stamping the tubular body on two sides analogously to FIG. 4;

8 shows the production of a nozzle channel by multi-sided stamping of the tubular body using a nozzle channel shaped body analogous to FIG. 5 and FIG. 9 shows the introduction of a nozzle channel into an end wall area of the embossed end area analogous to FIG. 6;

10 shows a longitudinal section through a second embodiment of a closure of heat exchanger channels in the first end area of a heat exchanger body;

11 shows a representation of a further exemplary embodiment of a closure of a plurality of heat exchanger channels of the tubular body in the first end region,

11a is a plan view of the end area,

11b shows a longitudinal section through the end area;

FIG. 12 shows a representation of a closure of the multiple heat exchanger channels by embossing on one side analogously to FIG. 4;

FIG. 13 shows a schematic representation similar to FIG. 12 of a production of a nozzle channel by means of a nozzle channel shaped body and removal of the same after stamping analogous to FIG. 5;

FIG. 14 shows the introduction of a nozzle channel into the end wall area of the end area produced by embossing analogously to FIG. 6;

FIG. 15 shows a closure of the heat exchanger channels by stamping the tubular body on two sides analogously to FIG. 7;

FIG. 16 shows the production of a nozzle channel by stamping the tubular body on two sides using a nozzle channel shaped body analogous to FIG. 8 ; FIG. 17 an introduction of a nozzle channel into an end wall area of the embossed end area analogously to FIG. 9;

18 shows a partial side view of a further exemplary embodiment of a heat exchanger according to the invention;

Figure 19 is a section taken along line 19-19 of Figure 18;

FIG. 20 shows a section similar to FIG. 19 through a further exemplary embodiment of a heat exchanger according to the invention;

21 shows a first exemplary embodiment of a heat exchanger channel with flow deflection elements;

22 shows a second exemplary embodiment of a heat exchanger channel with flow deflection elements;

23 shows a third exemplary embodiment of a heat exchanger channel with flow deflection elements;

24 shows a fourth exemplary embodiment of a heat exchanger channel with flow deflection elements;

25 shows a fifth exemplary embodiment of a heat exchanger channel with flow deflection elements;

26 shows a sixth exemplary embodiment of a heat exchanger channel with flow deflection elements;

27 shows a schematic representation of a partial section along line 27-27 in FIG. 28 through a further exemplary embodiment of a heat exchanger according to the invention, designed as a plate heat exchanger; FIG. 28 shows a position of the plate heat exchanger according to FIG. 27;

29 shows a representation of a distribution ring with nozzle channels for supplying refrigerant to the heat exchanger channels of a layer of the plate heat exchanger;

30 shows an exemplary embodiment of a refrigerant distributor which is routed through all layers of the plate heat exchanger;

31 shows an exploded view of a further exemplary embodiment of a heat exchanger according to the invention, designed as a coaxial heat exchanger;

32 shows a longitudinal section through a further exemplary embodiment of a heat exchanger according to the invention, also designed as a coaxial heat exchanger and

33 shows a schematic representation of an exemplary embodiment of a temperature testing system.

An exemplary embodiment shown in Fig. 1 of a refrigerant circuit designated as a whole by 10 comprises a refrigerant compressor 12, which compresses refrigerant supplied on a suction side 14 and discharges it on a high-pressure side 16, with the refrigerant compressed to high pressure being fed from the refrigerant circuit 10 to a heat exchanger 18 on the high-pressure side , which is capable of extracting heat from the refrigerant compressed to high pressure and dissipating it in the form of a heat flow 22 . The compressed refrigerant, which has been cooled by removing the heat flow 22, is fed to a control valve 24, which thus makes it possible to feed the refrigerant, which is still under pressure, to a heat exchanger, designated as a whole by 30, in which, after expansion of the refrigerant, heat is absorbed, in Fig. 1 identified as fluid stream 28.

For this purpose, the heat exchanger has a refrigerant distributor 32 connected to the control valve 24, to which the pressurized refrigerant is supplied and from which the refrigerant is supplied via nozzle channels 34 to the heat exchanger channels 36, in which the refrigerant expands while absorbing heat from the fluid flow 28 takes place, which runs in particular transversely or perpendicularly to the plane of the drawing.

After flowing through the heat exchanger channels 36 , the refrigerant enters a refrigerant collector 38 which collects the refrigerant from all the heat exchanger channels 36 and from which the refrigerant is then supplied to the suction side 14 of the refrigerant compressor 12 .

As shown enlarged in Fig. 2, in a first, simple embodiment of the heat exchanger 30 according to the invention, the heat exchanger channels 36 are formed by heat exchanger bodies 40 running parallel to one another, which extend from the refrigerant distributor 32 to the refrigerant collector 38, with the heat exchanger bodies 40 having a first end region 42 for connection to the refrigerant distributor 32 and a second end region 44 for connection to the refrigerant collector. A preferred design solution provides for the first end area 42 of the heat exchanger bodies 40 to protrude into an interior space 46 of the refrigerant distributor 32 and also for the first end area 42 to be provided with the nozzle duct 34, which thus leads out of the interior space 46 of the refrigerant distributor 32 refrigerant absorbs and delivers it to the heat exchanger channel 36, in which the refrigerant then expands and cools the heat exchanger body 40, so that it can absorb heat from the heat flow 28 flowing around the respective heat exchanger body.

The nozzle channels 34 are formed in the end regions 42 in such a way that they limit a mass flow of the refrigerant flowing from the interior 46 to the respective heat exchanger channel 36 .

For example, the design of the nozzle channels 34 with regard to their cross-sectional area is such that the refrigerant flows in them at the critical speed, ie in this case the speed of sound, and thus essentially an isenthalpic expansion of the refrigerant takes place in the nozzle channels 34 .

This means that in particular only after the refrigerant has exited the nozzle channels 34 in the respective heat exchanger channels 36 does the expansion leading to the cooling of the refrigerant take place.

In particular when using CO2 as the refrigerant, optionally with additives such as hydrocarbons, the refrigerant is supplied in the refrigerant circuit 10 to the refrigerant distributor 32 at a pressure level which is above the triple point, for example in the range between 10 bar and 160 bar, preferably in the range from 70 bar to about 140 bar and in particular in the range from 10 bar to about 70 bar. The pressure in the nozzle channel 34 is then reduced, but at the transition from the nozzle channel 34 to the heat exchanger channel 36 it is preferably still above the triple point of the refrigerant, in this case above the triple point of CO2, so that there is essentially a sublimation in the nozzle channel 34 is prevented.

The pressure in the nozzle channel 34 and in particular also up to the outlet of the nozzle channel 34 is preferably in the range of greater than 6 bar, for example in the range from approximately 6 bar to approximately 40 bar.

Thus, it is only in the heat exchanger channel 36 that the pressure is below the pressure of the refrigerant at the triple point, so that a solid phase of the refrigerant forms and sublimation of the refrigerant, i.e. in this case CO2 for example, occurs, so that the refrigerant on its way passes completely into the gaseous state through the heat exchanger channel 36 in the respective heat exchanger body 40 and can absorb heat from the fluid flow 28 in the process.

Gaseous refrigerant is preferably present at the second connection 44 of the heat exchanger body 40, which passes from the heat exchanger channel 36, in particular with its cross section, into an interior space 48 of the refrigerant collector and is collected by the latter and fed via the refrigerant circuit 10 to the suction side 14 of the refrigerant compressor 12.

In order to achieve this function, the nozzle channels 34 have, for example, a diameter of less than 0.1 mm and a length in the range of 0.05 mm to 5 mm.

The above dimensioning of the nozzle elements 34, in particular of the nozzle channels 34, and the above-mentioned operating conditions also apply in particular to all the exemplary embodiments described below. In the first exemplary embodiment according to Fig. 2, the heat exchanger body 40 is designed, for example, as a tubular body 50, which extends from the first end region 42 to the second end region 44 and has, for example, a substantially circular outer contour 52, with a tube wall 54 forming the outer contour 52 encloses the heat exchanger channel 36 on the peripheral side, as shown in FIGS. 3a and 3b.

When forming the first end region 42, it is necessary, as shown in FIGS. 4a to 4c, to close the heat exchanger channel 36. This is done, for example, by embossing the tubular body 50 on one side, with a first tubular wall area 56, which forms, for example, one half of the tubular body 50, being deformed in such a way that it comes to rest against an opposite, undeformed tubular wall area 58, so that the embossing of the tubular body 50 the embossed tube wall area 56 lies tightly against the undeformed tube wall area 58 along a contact surface 62 and thus closes the heat exchanger channel 36 in the area of the connection section 42, this taking place in particular with the formation of an end wall area 64 closing the heat exchanger channel 36, as shown in FIGS. 4a to 4c .

In order to supply the heat exchanger channel 36 with refrigerant, however, it is necessary to introduce the nozzle channel 34 .

This can be done in many different ways.

As shown in Fig. 5, for example, it is possible to arrange a nozzle channel shaped body 72 in the region of contact surface 62 when stamping tube wall region 56 into tube wall region 58 before laying tube wall region 56 against tube wall region 58, which has the dimensions of the 5a to 5b, so that the tube wall area 56 rests against the tube wall area 58 along the contact surface 62, but not in the area of the nozzle channel shaped body 72.

If the molded nozzle channel body 72 is subsequently removed, for example by pulling it out axially, the nozzle channel 34 remains in the end section 42, as shown in FIG.

As an alternative to providing the nozzle channel shaped body, there is also the possibility, as shown in Fig. 6a to c, of introducing the nozzle channel 34 into the end wall area 64 after closing the heat exchanger channel 36 in the area of the first connection section 42 by machining, for example laser machining, so that the nozzle channel 34 passes through the end wall area 64 and thus the pipe wall area 56 bears against the pipe wall area 58 over the entire surface along the contact surface 62 formed during the embossing.

Starting from the tubular body 50 according to FIG. 3, however, there is also the possibility of closing the heat exchanger channel 36 in that, for example, two opposite tube wall regions 56a and 56b are stamped, or possibly more towards one another, so that between these tube wall regions 56a and 56b each undeformed tube wall areas 58a and 58b remain and thus end wall areas 64a and 64b are formed by the embossing of the tube wall areas 56a and 56b towards one another, which close the heat exchanger channel 36 of the heat exchanger body 40, as shown in FIGS. 7a, 7b and 7c. Even with such an embossing of the tubular body 50 to form the end region 42, there are two options for introducing the nozzle duct, namely on the one hand, as shown in Fig. 8, by inserting the nozzle duct shaped body 72 during the embossing, so that the embossing of the tube wall regions 56a and 56b leads to this 8a and 8b and after removing the nozzle channel Iformed body 72, the nozzle channel 34 remains between the tube wall regions 56a and 56b stamped together.

Alternatively, it is also possible, as shown in Fig. 9, to incorporate a nozzle channel 34 in one of the end wall areas 64a, 64b after stamping the tube wall areas 56a and 56b together to form the end wall areas 64a and 64b, for example by machining, in particular laser machining then penetrates the respective end wall area 64a or 64b.

With all the options for producing the nozzle channel 34 according to FIGS. 5 and 6 as well as 8 and 9, the embossing of the pipe wall areas 56 and 58 takes place within the outer contour 52, so that the heat exchanger body 40 in the area of the first end area 42 does not extend beyond the outer contour 52 of the tube body 50 extends out, but the deformed tube wall areas 56 are all within the outer contour 52.

This allows the end region 42 to be easily inserted into the refrigerant distributor 32, since an opening 82 in a wall 84 of the refrigerant distributor 32 can be dimensioned according to the outer contour 52 of the respective tubular body 50 and a connection between the wall 84 of the refrigerant distributor 32 and the tubular body 50 can take place in an area outside of the end area 42, so that a simplified production of the connection between the tubular bodies 50 and the refrigerant distributor 32 is possible, as shown in FIG. 10 using the solution according to FIG. It is preferably also provided that the refrigerant distributor 32 is provided with thermal insulation 86, which prevents unwanted cooling of the refrigerant already in the interior 46 of the refrigerant distributor 32, so that this occurs even at a pressure that is higher than the pressure at the triple point a solid phase of the refrigerant before it enters the nozzle channels 34 is prevented as far as possible.

In a further exemplary embodiment, shown in FIG. 11, the heat exchanger body 40' is designed such that it has a tubular body 50' in which a plurality of heat exchanger channels 36 are arranged, with each heat exchanger channel 36 being surrounded by tube walls 54'.

To form the first end area 42' of the connecting channels 36, as shown in Fig. 12a to c, analogously to the procedure according to Fig. 4, the tube wall area 56 belonging to the respective heat exchanger channel 36 is embossed in the direction of an undeformed tube wall area 58, forming the contact surface 62 such that there is also a tight seal in the area of the contact surface 62 .

An end wall area 64 is thus formed for each heat exchanger channel 36, which closes this heat exchanger channel 36 in a similar way to that described in detail in connection with FIG. 4, to which reference is made in this regard.

Analogously to the procedure according to Fig. 5, a nozzle channel 34 can be formed on the respective end region 42', in particular by inserting a nozzle channel shaped body 72 between the tube wall regions 56 and 58 to be stamped in order to stamp the tube wall region 56, so that when the tube wall region is molded on 56 to the tube wall area 58 the Contact surface 62 in the area of the molded nozzle channel body 72 does not close tightly, but after the molded nozzle channel body 72 has been pulled out, as shown in FIG.

As an alternative to this, it is also possible, as shown in connection with Fig. 14, to work the nozzle channel 34 into the end wall region 64 formed during stamping by machining, for example with a laser beam, in a procedure analogous to that in detail in connection with Fig. 6 described, reference being made to the full content of the description for this purpose.

Analogously to the procedure for the formation of the first connection section 42 in the tubular body 50, there is the possibility in the tubular body 50' with a plurality of heat exchanger channels 36 to also close the individual end regions 42' by embossing two opposite tube wall regions 56a and 56b in the direction towards one another, with as also already described in connection with FIG. 7 - form the end wall areas 64a and 64b lying between the undeformed tube wall areas 58a and 58b.

Thus, with regard to the closure of the heat exchanger channels 36 by embossing the tube wall regions 56a and 56b lying opposite one another, reference can be made in full to the explanations in connection with FIG. 7 .

The respective nozzle channel 34 can also be provided in a manner similar to that described in connection with the tubular body 50 . According to Fig. 16, for example, in order to press pipe wall areas 56a and 56b together, the nozzle channel shaped body 72 is to be inserted between the pipe wall areas 56a and 56b to be pressed and to be removed after the stamping has taken place, so that the nozzle channel 34 corresponding to the nozzle channel gauge 72 is placed between the stamped ones Tube wall portions 56a and 56b remains.

In this regard, too, reference can be made in full to the corresponding explanations in connection with FIG. 8 .

As an alternative to this, it is also conceivable, as shown in Fig. 17, to incorporate a nozzle channel 34, for example by laser machining, into the end wall regions 64a and 64b that form when the tube wall regions 56a and 56b are stamped together, for example in one of them or optionally in both , as shown in Fig. 17b.

In this regard, too, full reference can be made to the explanations in connection with FIG. 9 .

In all exemplary embodiments comprising a tubular body 50', the tubular wall regions 56a and 56b are also embossed in such a way that their final shape does not protrude beyond the outer contour 52' of the tubular body 50', so that the tubular body 50' can, analogously to the solution according to FIG. 10, be placed in openings 82 of the wall 84 of the refrigerant distributor 32 can be introduced and connected to the wall 84 outside of the first end region 42 in order to be able to produce the heat exchanger 30 as simply as possible. In a further exemplary embodiment of a heat exchanger 30 according to the invention, shown in Figs. 18 and 19, the refrigerant distributor 32 comprises an elongate, for example tube-like body with a wall 33 which, preferably, accommodates a receptacle 35 for the end region 42 of the heat exchanger body 40 designed as a tubular body 50 is adapted in a form-fitting manner to the first end region 42, which is designed in particular as a blunt end of the tubular body 50, so that the end region 42 rests with its end wall region 54 on a base 37 of the receptacle 35 and a side wall 39 of the receptacle 35 has an outer contour 52 of the tubular body 50 , In particular the circular outer contour of the tubular body 50 includes.

After the end region 42 has been inserted into the receptacle 35, it can be tightly connected to the wall 33 of the distributor 32 in a simple manner, for example by joining.

Furthermore, a nozzle channel 34, which is designed according to the dimensions corresponding to the above exemplary embodiments and functions according to the operating conditions mentioned, is preferably incorporated in an area of the base 37 that covers the front side of the heat exchanger channel 36 and, starting from this, which extends into the interior space 46 of the refrigerant distributor 32 extends, the incorporation of the nozzle channel 34 being carried out, for example, by mechanical drilling or laser machining.

Furthermore, in particular the receptacle 35 in the wall 33 of the refrigerant distributor 32 is incorporated by mechanical processing, for example drilling or milling, and in particular is dimensionally precisely matched to the outer contour 52 of the tubular body. In a further exemplary embodiment of such a heat exchanger, shown in FIG. 20, two receptacles 35 can be incorporated into a side wall 33s of the refrigerant distributor 32, for example with an oval cross-sectional shape, with a tubular body 50 being inserted in the same way in each of these receptacles 35. as described in connection with the previous embodiment.

Furthermore, the respective nozzle channel 34 , which extends into the interior 46 , is also worked out in the respective bottom 37 of the respective receptacle.

In this exemplary embodiment as well, the dimensions of the nozzle channel 34 and the pressures in the refrigerant distributor 32 and in the respective nozzle channel 34 are therefore identical to those of the preceding exemplary embodiments.

In the case of the elongated heat exchanger channels 36 required according to the invention, there is the problem, in particular when the refrigerant, in particular CO2, sublimes in them, that there is no good heat transfer to the solid refrigerant.

For this reason, in an advantageous embodiment of the solution according to the invention, it is provided that the heat exchanger channels 36 have flow deflection areas 92, as shown in FIG the solid refrigerant takes place.

For example, the flow deflection areas 92 could be arranged in such a way that they are each arranged between channel sections 94 running in a straight line. The flow deflection areas 92 are preferably designed in such a way that they cause a flow deflection, for example in relation to a straight flow propagation direction 96, of for example at least 20°, preferably at least 40°, in order to achieve sufficiently large turbulence of the sublimating refrigerant.

In the simplest case, the respective flow deflection area 92 could be designed as a kinked course of the heat exchanger channel 36 .

Another advantageous solution, shown for example in Fig. 22, provides between the straight channel sections 94 flow deflection areas 92 ', which do not represent a kinking course of the heat exchanger channel 36, but a curved course with a radius of curvature R, which is a multiple of a central channel cross section. preferably less than 40 times the mean channel cross-section.

The change in curvature causes, for example, a direction deflection of the order of 90° with respect to the rectilinear propagation of the flow 96.

In the case of the exemplary embodiment illustrated in FIG. 22, deflections in alternating directions take place in successive flow deflection regions 92'.

However, the flow deflection areas 92' can also be arranged, as for example in Fig. 23, so that two consecutive flow deflection areas 92' with their curvature cause a deflection in the same direction and then again in the opposite direction, whereby in each case between two flow deflection areas deflecting in the same direction 92' straight channel sections 94 lie. In a further embodiment, shown in Fig. 24, the flow deflection areas 92" are curved in such a way that they each cause a flow deflection by an angle of the order of approximately 180°, with successive flow deflection areas 92" being connected to one another by straight channel sections 94 .

As an alternative to this, it is provided in the exemplary embodiment according to FIG. 25 that the flow deflection regions 92', which have a radius of curvature, are arranged directly one after the other, so that there are no longer any channel sections 94 running in a straight line between them.

In the embodiment according to FIG. 25, the flow deflection sections 92' lead to flow deflections in the order of approximately 20° to 90°.

In a further exemplary embodiment, shown in Fig. 26, the flow deflection areas 92" also follow one another directly, with these flow deflection areas 92" each causing a flow deflection with the radius of curvature R., which, however, is in the order of approximately 180°, so that in particular the Course of the heat exchanger channel 36 can also be referred to as meandering.

In a further exemplary embodiment of a heat exchanger 30" according to the invention, shown in FIGS. 27, 28 and 29, this is designed as a plate heat exchanger 100, which has layers 104 lying one above the other in a stacking direction 102, in which on the one hand the heat exchanger channels 36 run and on the other hand separated from This medium to be cooled, in this case preferably a fluid, such as a liquid, a gas or a phase-changing fluid, such as brine, is guided. For example, each layer 104 comprises two layered metal sheets 104a, 104b lying one on top of the other, which enclose the heat exchanger channels 36 between them and together form the heat exchanger bodies 40" in the layers 104, with the heat-emitting medium flowing through the layers 104 between the heat exchanger bodies 40".

On the one hand, the refrigerant distributor 32" runs parallel to the stacking direction 102 and/or the refrigerant collector 38" runs parallel to the stacking direction 102 and penetrates the various layers 104.

Such a layer 104 for forming the heat exchanger channels 36 is shown in FIG. 28, the channels 36 in the respective layer 104 being separated from one another by channel separations 106 provided in this layer 104, for example formed by the layer plates 104a, 104b.

Furthermore, starting from the refrigerant distributor 32", at least one nozzle duct 34 leads to the respective heat exchanger duct 36, in which case all of the nozzle ducts 34 are formed in the wall 84" of the refrigerant distributor 32" and not in the heat exchanger ducts 36.

For example, the wall 84" is formed in the respective layer by a distributor body 108, in which the individual nozzle channels 34 are incorporated, whereby this distributor body 108 can also be aligned relative to the respective layer 104 of the plate heat exchanger by means of an orientation element, for example a nose 112 .

The distributor bodies 108 are each part of the coolant distributor 32" and form the wall 84" in the respective position as shown in FIG.

The distributor bodies 108 can be formed in one piece, with the nozzle channels 34 being incorporated into the wall 84'' by laser machining. As an alternative to this, the distributor body 108 is divided in two, with the separating plane T between the distributor body elements 108a and 108b running through the nozzle channels 34 and these being produced in that the distributor body elements 108a and 108b are embossed with one another and for embossing in the separating plane T at the points of the to be produced Nozzle channels 34 are arranged nozzle moldings 72, so that when the distribution body elements 108, 108b are stamped in the area of the parting plane T, the nozzle channels 34 are formed, as described in connection with the production of a nozzle channel 34 with FIGS. 5, 8, 13 and 16, whereupon content is referred to.

Alternatively, it is also conceivable, as shown in Fig. 30, to form the refrigerant distributor 32" by a tubular body 114, which passes through all layers 104 and in each of the layers 104 in which the heat exchanger channels 36 are arranged, with heat exchanger channels to these 36 leading nozzle channels 34 are provided.

In a further exemplary embodiment of a heat exchanger 30"' according to the invention, shown in Fig. 31, the heat exchanger channels 36 run between an inner body 122 and an outer body 124 enclosing the inner body 122, or they are incorporated into one of the same, with the inner body 122 enclosing a space 126 , In which a heat-emitting medium is arranged, in particular flows through it.

The inner body 122 and the outer body 124 thus together form the heat exchanger body 40'''.

However, it is also possible to arrange several such inner bodies 122 and outer bodies 124, in particular coaxially with one another. To feed the heat exchanger channels 136, a distribution body 128 is provided, which is provided with the nozzle channels 34 and extends between the inner body 122 and the outer body 124 and thus an interior space 46"' located between the inner body 122 and the outer body 124 of the also in this area by the inner body 122 and the outer body 124 formed coolant distributor 32"' delimited, wherein opposite the distributor body 128 the interior 46"" is closed by an annular body 132.

In this case, for example, the refrigerant is supplied to the interior 46'' via a connection 134 from the refrigerant circuit.

In the same way as in the previous exemplary embodiments, the heat exchanger channels 36 in this exemplary embodiment also preferably run in a meandering manner, similar to the course in FIG. 25, so that reference can be made to the explanations relating to FIG. 25 in this regard.

Furthermore, the outer body 124 is provided with a connection 136 for the expanded refrigerant to be discharged, with the interior 48 of the refrigerant collector 38" forming between the inner body 122 and the outer body 124 following the second end regions 44" of the heat exchanger channels 36.

In a further exemplary embodiment of a heat exchanger 30"" according to the invention, shown in FIG. 32, the heat exchanger channels 36 are also located between the inner body 122 and the outer body 124, and the heat-emitting fluid also flows through the inner space 126. In contrast to the above exemplary embodiment, the refrigerant distributor 32"" is formed by a conical inner body 142 and a conical outer body 144 running at a distance from this, which form an annular gap or conical gap 146 between them, the flow cross section of which also limits the mass flow to via a connection 148 incoming pressurized refrigerant acts and thus has the same effect as the plurality of nozzle channels 34 in the distribution ring 128 of the previous embodiment.

Thus, the interior space 46"" of the coolant distributor 32"" simultaneously serves as a flow-restricting element for the inflowing coolant.

Alternatively, a distribution body similar to the distribution body 128 with nozzle channels 34 can also be provided between the conical inner body 142 and the conical outer body 144 .

In addition, the interior space 48 of the refrigerant collector 38 ″ for discharging the refrigerant expanded in the heat exchanger channels 36 is also formed between the inner body 122 and the outer body 124 following the second end region 44 of the heat exchanger channels 36 .

A variant of a refrigerant circuit 10' according to the invention is, as shown in Fig. 33, part of a temperature testing system designated as a whole by 200, in particular for carrying out temperature tests, which has, for example, a thermally insulated test chamber 210 in which a test object 212 is arranged, which cold , in particular low temperatures below a temperature of about 223 K is to be exposed.

For this purpose, a gaseous medium 214 , for example, is arranged in the test chamber 210 , which medium surrounds the test object 12 and is circulated, for example, by means of a blower unit 216 . The gaseous medium 214 is cooled in order to reach the low temperatures by the first heat exchanger 30, which is circulated in particular in the refrigerant circuit 10 'and compressed by the compressor 12 refrigerant in the same way and with the same operating conditions, as explained in connection with Fig. 1, is operated and in particular the heat exchanger is designed and operated according to one of the preceding exemplary embodiments.

However, in this case the heat exchanger 18 is divided into two, namely comprising a heat exchanger 18a, in which the refrigerant compressed by the compressor 12 is first cooled by ambient air in order to release the heat flow 22a, and subsequently comprising the heat exchanger 18b, which is not through a whole Refrigeration system 220 explained in more detail is cooled in order to absorb the heat flow 220b and to liquefy the refrigerant.

However, in this exemplary embodiment, a supply line to a second heat exchanger 230 branches off from the refrigeration circuit downstream of heat exchanger 18b, in which a control valve 232 is arranged, which controls an inflow of the refrigerant to the second heat exchanger 230, with a return flow from the heat exchanger 230 to the suction connection 14 of the refrigerant compressor has a non-return valve 234 .

The second heat exchanger 230 is operated at a higher pressure level, so that when the heat flow 228 is absorbed from the medium 214 in the test chamber 210, there is no sublimation of the refrigerant, but conventional evaporation thereof. A controller 250 controls the inflow of refrigerant from refrigerant circuit 10 via control valve 24 and control valve 232 so that, depending on the required temperature of medium 214, either second heat exchanger 230, for example at temperatures above 220 K, or first heat exchanger 30, for example at temperatures below 220 K, is used.

Furthermore, for example, the test chamber 10 is also assigned a heater 214 which allows the test chamber 210 and thus the test object 212 to also be heated if necessary in order to implement temperature cycles for testing the test object 212 .

The controller 250 preferably also controls the heating 240 in such a way that there is the possibility of exposing the medium 214 and also the object 212 to predetermined temperature cycles.

Alternatively, another solution provides for the heat exchangers 30 and 230 to interact with a test medium that is liquid, for example a brine, or gaseous or a phase-changing medium, in that this medium flows through the heat exchangers 30, 230 and the heater 214 and to it the test object 212 is guided.

Claims

- 47 -

WO 2022/101140 PCT/EP2021/080954

P A T E N T A N T L A G E S

1. Heat exchanger (30), comprising a refrigerant distributor arranged on the inlet side of the heat exchanger, at least one nozzle element (34, 146) running from the refrigerant distributor (32) and limiting a mass flow of the refrigerant, at least one nozzle element (34, 146) attached to the at least one nozzle element adjoining heat exchanger channel (36), which in turn runs in a heat exchanger body (40), and a refrigerant collector (38) arranged on the outlet side of the heat exchanger (30) and adjoining the at least one heat exchanger channel (36) on its side opposite the nozzle element (34, 146) .

2. The heat exchanger as claimed in claim 1, characterized in that the heat exchanger body (40) is designed to enclose the at least one heat exchanger channel (36) on the peripheral side.

3. Heat exchanger according to claim 1 or 2, characterized in that the heat exchanger body (40) is designed as a tubular body (50). . Heat exchanger according to one of the preceding claims, characterized in that a heat exchanger channel (36) runs in the heat exchanger body (40).

5. Heat exchanger according to one of claims 1 to 3, characterized in that a plurality of heat exchanger channels (36) runs in the heat exchanger body (40).

6. Heat exchanger according to one of the preceding claims, characterized in that the at least one heat exchanger channel (36) has at least one flow deflection area (92). - 48 -

WO 2022/101140 PCT/EP2021/080954

7. The heat exchanger as claimed in claim 6, characterized in that each flow deflection region (92) effects a flow deflection at an angle of at least 20° with respect to a rectilinear direction of flow propagation.

8. The heat exchanger as claimed in claim 7, characterized in that the respective flow deflection region (92) effects a flow deflection at an angle of at least 40° with respect to a rectilinear direction of flow propagation.

9. Heat exchanger according to one of claims 6 to 8, characterized in that the at least one heat exchanger channel (36) has flow deflection regions (92) which connect channel sections (94) running at an angle to one another.

10. Heat exchanger according to one of claims 6 to 9, characterized in that the at least one heat exchanger channel (36) has at least one curved flow deflection area (92').

11. The heat exchanger as claimed in claim 10, characterized in that the at least one curved flow deflection area (92') has a radius of curvature (R.) which is at most 40 times an average diameter of the heat exchanger channel (36).

12. Heat exchanger according to claim 10 or 11, characterized in that several flow deflection areas (92) are arranged in succession in the respective heat exchanger channel (36). - 49 -

WO 2022/101140 PCT/EP2021/080954

13. Heat exchanger according to one of the preceding claims, characterized in that the respective heat exchanger channel (36) is formed between a first end region (42) associated therewith and formed by the heat exchanger body (40) and connected to the refrigerant distributor (32) and a first end region (42) connected to the refrigerant collector ( 38) connected second end region (44).

14. Heat exchanger according to claim 13, characterized in that the first end region (42) of the heat exchanger body (40) is arranged engaging in the refrigerant distributor (32).

15. Heat exchanger according to claim 13 or 14, characterized in that the first end region (42) engages in a receptacle (35) of the coolant distributor (32).

16. Heat exchanger according to claim 15, characterized in that the receptacle (35) is arranged on a wall (33) of the refrigerant distributor (32).

17. Heat exchanger according to claim 15 or 16, characterized in that the receptacle (35) accommodates an end wall area (64) of the heat exchanger body (40).

18. Heat exchanger according to one of claims 15 to 17, characterized in that the receptacle (35) comprises the heat exchanger body (40) in the area of its outer contour (52) at least in the area of a peripheral segment.

19. Heat exchanger according to one of claims 15 to 18, characterized in that the nozzle element (34) extends from a region of the receptacle (35) adjoining the heat exchanger channel (36) to the interior (46) of the refrigerant distributor (32). - 50 -

WO 2022/101140 PCT/EP2021/080954

20. Heat exchanger according to one of the preceding claims, characterized in that the first end region (42) of the heat exchanger body (40) extends into an interior (46) of the refrigerant distributor (32).

21. Heat exchanger according to claim 20, characterized in that the respective heat exchanger channel (36) is closed at the first end area by an embossing of at least one wall area (56) of the heat exchanger body (40).

22. Heat exchanger according to claim 21, characterized in that the at least one wall region (56) of the heat exchanger body (40) formed by the embossing lies within an outer contour (52) of the heat exchanger body (50).

23. Heat exchanger according to claim 21 or 22, characterized in that the embossing of the wall region (56) of the heat exchanger body (40) is designed as a one-sided embossing with partial preservation of an outer contour (52) of the heat exchanger body (50) opposite thereto.

24. Heat exchanger according to one of claims 21 to 23, characterized in that the embossing is designed as a multi-sided embossing of wall regions (56a, 56b) of the heat exchanger body (50').

25. Heat exchanger according to one of the preceding claims, characterized in that the nozzle element is designed as a nozzle channel (34). 26. Heat exchanger according to one of claims 19 to 25, characterized in that at least one nozzle element (40, 146) for supplying refrigerant to the respective heat exchanger channel (36) is arranged on the first end region (42).

27. Heat exchanger according to claim 26, characterized in that the nozzle element (34) is incorporated into the end region (42).

28. Heat exchanger according to one of claims 21 to 27, characterized in that the nozzle element (34) is arranged in the area of a wall area (56, 64) deformed by the embossing.

29. Heat exchanger according to claim 28, characterized in that the nozzle element (34) is incorporated into an end wall region (64) formed by the embossing.

30. Heat exchanger according to claim 28, characterized in that the nozzle element (34) is formed by a nozzle channel shaped body (72), against which the embossing of the at least one wall region (56) has taken place.

31. Heat exchanger according to the preamble of claim 1 or according to one of the preceding claims, characterized in that a plurality of heat exchanger channels (36) lie next to the heat exchanger body (40') in a plane in which the heat exchanger body (40') extends in the form of a plate.

32. The heat exchanger as claimed in claim 31, characterized in that a plurality of heat exchanger bodies (40′) are arranged one above the other in a stacking direction (102) with extension planes parallel to one another. 33. Heat exchanger according to claim 31 or 32, characterized in that the plurality of heat exchanger bodies (40') are connected to a refrigerant distributor (32') extending in the stacking direction (102).

34. Heat exchanger according to claim 33, characterized in that in a wall area of the refrigerant distributor (32) on which at least one heat exchanger channel (36) of the heat exchanger body (40') adjoins, a nozzle element (34) for supplying refrigerant into the respective heat exchanger channel (36) is arranged.

35. Heat exchanger according to one of the preceding claims, characterized in that the heat exchanger channels (36) connect with their first end regions (42) to the nozzle elements (34) and with their second end regions (44') open into the refrigerant collector (38'). .

36. Heat exchanger according to claim 35, characterized in that the refrigerant collector (38') extends in the stacking direction (102).

37. Heat exchanger according to the preamble of claim 1 or according to one of the preceding claims, characterized in that the heat exchanger channels (36) between an inner body (122) enclosing a channel for heat-emitting medium and an inner body (122) on its side opposite the heat-emitting medium side enclosing the outer body (124), and that the refrigerant distributor (32'') is arranged in the area of a first end side of the inner body (122) and the outer body (124) and in the area of a second end side of the inner body (122) opposite the first end side and of the outer body (124) the refrigerant collector (38''') is arranged. - 53 -

WO 2022/101140 PCT/EP2021/080954

38. The heat exchanger according to claim 37, characterized in that the nozzle elements (34) are arranged in a nozzle element carrier (128) located between the inner body (122) and the outer body (124) and that at least one nozzle element (34) in each case is in one of the heat exchanger channels (36) flows.

39. Heat exchanger according to claim 37, characterized in that a nozzle element (146) limiting the mass flow of the refrigerant is arranged in the refrigerant distributor (32''') and supplies refrigerant to all heat exchanger channels (36). 0. Heat exchanger according to one of the preceding claims, characterized that a heat-emitting medium supplies heat through the respective heat exchanger body (40) to the refrigerant in the respective heat exchanger channel (36) 1. Heat exchanger according to Claim 40, characterized in that the at least one heat exchanger body (40) is in direct contact with the heat-exchanging medium 2. Heat exchanger according to one of the preceding claims, characterized in that the heat exchanger (30) is provided in the region of the refrigerant distributor (32) with thermal insulation (86) surrounding it in particular (12), one to the verdic Heten refrigerant heat extracting heat exchanger (18), and fed with the compressed refrigerant heat absorbing heat exchanger (30), which is designed according to one of the preceding claims. - 54 -

WO 2022/101140 PCT/EP2021/080954 4. Refrigerant circuit according to Claim 43, characterized in that the refrigerant supplied to the refrigerant circuit (10) has a pressure above a triple point of the refrigerant distributor (32) and with this in the refrigerant distributor ( 32) occurs. 5. Refrigerant circuit according to Claim 43 or 44, characterized in that the pressure of the refrigerant in the heat exchanger channels (36) is below the triple point of the refrigerant and that the refrigerant collector (38) is connected to a suction side (14) of the refrigerant compressor (12) connected is. 6. Refrigerant circuit according to claim 43 to 45, characterized in that in the refrigerant circuit (10) a supply of refrigerant into the refrigerant distributor (32) takes place in a supercritical state of the same. 7. Refrigerant circuit according to one of claims 43 to 46, characterized in that in the refrigerant circuit (10) there is a supply of refrigerant with a liquid and a gaseous phase in the refrigerant distributor (32). 8. Refrigerant circuit according to one of claims 43 to 47, characterized in that in the refrigerant circuit (10) there is a supply of refrigerant in the liquid phase in the refrigerant distributor (32). 9. Refrigerant circuit according to one of claims 43 to 48, characterized in that the refrigerant in the heat exchanger channels (36) is present at a pressure corresponding to a sublimation pressure of the refrigerant. - 55 -

WO 2022/101140 PCT/EP2021/080954

50. Refrigerant circuit according to one of claims 43 to 49, characterized in that the nozzle element (34) is dimensioned such that there is no expansion of the refrigerant at a pressure below the triple point of the same.

51. Temperature testing system, characterized in that it has a refrigerant circuit (10) according to one of claims 43 to 50, and that the heat-absorbing first heat exchanger (30) according to one of claims 1 to 42 with a medium acting on a test object (214), arranged in particular in a test chamber (210).

52. Temperature test system according to claim 51, characterized in that the refrigerant circuit supplies compressed refrigerant to a second heat exchanger (230), in which this evaporates at a pressure which is above the pressure of the triple point of the refrigerant.

53. A method for operating a refrigerant circuit (10) comprising a refrigerant compressor (12), a heat exchanger (18) extracting heat from the compressed refrigerant and a heat-absorbing heat exchanger (30) fed with the compressed refrigerant, which is designed according to one of the preceding claims, wherein in the refrigerant circuit (10), the refrigerant is supplied to the refrigerant distributor (32) at a pressure above a triple point of the refrigerant.

54. The method according to claim 53, characterized in that a pressure of the refrigerant is maintained in the heat exchanger channels (36), which is below the triple point of the refrigerant. - 56 -

WO 2022/101140 PCT/EP2021/080954

55. The method according to claim 53 or 54, characterized in that in the refrigerant circuit (10) the refrigerant is supplied to the refrigerant distributor (32) in a supercritical state thereof.

56. The method according to any one of claims 53 to 55, characterized in that in the refrigerant circuit (10) the refrigerant is supplied with a liquid and a gaseous phase to the refrigerant distributor (32).

57. The method according to any one of claims 53 to 56, characterized in that in the refrigerant circuit (10) the refrigerant is supplied in the liquid phase to the refrigerant distributor (32).

58. The method according to any one of claims 53 to 57, characterized in that the refrigerant in the heat exchanger channels (36) is kept at a pressure corresponding to a sublimation pressure of the refrigerant.

59. The method according to any one of claims 53 to 58, characterized in that the nozzle element (34) is supplied with the refrigerant at such a pressure and is guided in this that there is no expansion of the refrigerant to a pressure below the triple point of the same.

60. Method for operating a temperature testing system, which has a refrigerant circuit (10') according to one of Claims 43 to 50, and a heat-absorbing first heat exchanger (30) according to one of Claims 1 to 42, which is connected to a medium (214), in particular in a test chamber (210) thereof, and in which the refrigerant circuit (10') is operated according to a method according to one of Claims 53 to 59. - 57 -

WO 2022/101140 PCT/EP2021/080954

61. Procedure for operating a temperature testing system

Claim 60, characterized in that compressed refrigerant is fed from the refrigerant circuit (10') to a second heat exchanger (230) interacting with the medium (214) and is evaporated therein at a pressure which is in particular above the pressure of the triple point of the refrigerant.

62. The method according to claim 61, characterized in that either the first heat exchanger (30) or the second heat exchanger (230) is fed with refrigerant from the refrigerant circuit (10').

63. The method as claimed in claim 62, characterized in that the first heat exchanger (30) or the second heat exchanger (230) is fed with refrigerant by a controller depending on the temperature of the medium (214).