WO2022101139A2

WO2022101139A2 - Temperature control system and method for operating a temperature control system

Info

Publication number: WO2022101139A2
Application number: PCT/EP2021/080951
Authority: WO
Inventors: Andreas Wagner; Thomas Rieger; Philipp JEHS
Original assignee: CTS Clima Temperatur Systeme GmbH
Priority date: 2020-11-13
Filing date: 2021-11-08
Publication date: 2022-05-19
Also published as: DE102020130063A1; WO2022101139A3; EP4244548A2

Abstract

The invention relates to a temperature control system, comprising: a medium to be temperature-controlled, with which at least one heat exchanger for absorbing heat from the medium interacts; a refrigerant circuit which supplies refrigerant to the at least one heat exchanger for expansion; for this purpose, at least one compressor stage which compresses refrigerant expanded in the heat exchanger; a heat exchanger which dissipates heat from the compressed refrigerant; and a control valve for controlling the mass flow of the compressed refrigerant to the at least one heat exchanger for absorbing heat; wherein a first heat exchanger is designed such that, in said heat exchanger, the refrigerant enters a refrigerant distributor following a feed line and, proceeding from this, enters at least one heat exchanger channel through at least one nozzle element which limits the mass flow, and expands in said heat exchanger.

Description

TEMPERATURE CONTROL SYSTEM AND METHOD OF OPERATING A TEMPERATURE CONTROL SYSTEM

The invention relates to a temperature control system, comprising a medium to be temperature-controlled, with which at least one heat exchanger interacts to absorb heat from the medium, and a refrigerant circuit which supplies the at least one heat exchanger with refrigerant for expansion and, for this purpose, at least one compressor stage that compresses refrigerant expanded in the heat exchanger and a heat exchanger that dissipates heat from the compressed refrigerant and a control valve for controlling the mass flow of the compressed refrigerant to the at least one heat exchanger for absorbing heat.

Such temperature control systems are known from the prior art, but with these there is the problem that these temperatures, which are below a temperature in the range from 220 K to 230 K, in particular below approximately 223 K, cannot be reasonably implemented.

The invention is therefore based on the object of improving a temperature control system of the generic type in such a way that such temperatures can also be achieved with the least possible effort.

In a temperature control system of the type described above, this object is achieved according to the invention in that the first heat exchanger is designed in such a way that, following a supply line, the refrigerant enters a refrigerant distributor and, starting from there, enters at least one heat exchanger channel through at least one nozzle element that limits the mass flow and expanded in this.

In order to achieve the desired low temperatures, it is expediently provided that the refrigerant expands by sublimation in the heat exchanger channel that is connected to the nozzle element. For this purpose, it is preferably provided that the refrigerant is present both in the refrigerant distributor and in the nozzle element at a pressure which is above the pressure of the triple point of the refrigerant, which is in particular CO2, optionally with additives such as hydrocarbons. and which then expands on entering the heat exchanger channel to a pressure which is below the triple point of the refrigerant, so that the refrigerant changes partly into the solid phase and partly into the gas phase and from there the solid phase then changes into the gas phase by sublimation .

In a heat exchanger of this type, it is possible in particular to use environmentally friendly refrigerants, for example comprising carbon dioxide (CO2), optionally with additives, for example hydrocarbons.

Alternatively or additionally, the object mentioned at the beginning is achieved according to the invention in a temperature system of the type described at the outset in that a first and a second heat exchanger interact with the medium, that the first heat exchanger is designed to cool the medium to temperatures of less than approximately 223 K that the second heat exchanger is designed to cool the medium to temperatures above approximately 223 K and that the refrigerant circuit is designed such that during operation it feeds either refrigerant into the first heat exchanger or into the second heat exchanger.

In the context of the application, a temperature of approximately 223 K means temperatures in the range from 220 K to 230 K, preferably from 220 K to 225 K.

The advantage of this solution can be seen in the fact that temperatures above approximately 223 K can be achieved with the second heat exchanger in a simple manner and with high efficiency, and that temperatures below approximately 223 K can advantageously be realized with the first heat exchanger. A particularly favorable solution provides that the refrigerant circuit has a supply line to the first heat exchanger and a supply line to the second heat exchanger, and that a control valve controlled by a controller of the refrigerant circuit is provided in each of the supply lines for controlling the mass flow supplied to the respective heat exchanger.

A change between the operation of the first heat exchanger and the second heat exchanger can thus be implemented in a simple manner.

In addition, it is preferably provided that, depending on the required temperature of the medium to be cooled in the room, a controller feeds compressed refrigerant from the refrigerant circuit to either the second heat exchanger or the first heat exchanger in a mass flow-controlled manner in order to reduce the amount of heat absorbed by the respective heat exchanger and thus also the to control the temperature of the medium.

A simple way of operating the second heat exchanger provides that an expansion element is arranged in the supply line to the second heat exchanger, which expands the refrigerant so that it can absorb heat in the second heat exchanger.

In addition to the control valve mentioned above, the expansion element could be provided in the supply line to the second heat exchanger.

However, it is particularly advantageous if the control valve is operated in such a way that it simultaneously acts as an expansion element for the second heat exchanger. In principle, any refrigerant suitable for such temperatures can be used in the present invention. The use of carbon dioxide (CO2) as a refrigerant is particularly advantageous for reasons of environmental compatibility.

In particular, it is advantageously provided that the refrigerant in the second heat exchanger is expanded at a pressure above the sublimation range of the refrigerant, so that it can be operated in a simple manner.

The second heat exchanger is preferably designed structurally as a conventional heat exchanger, in which the supplied refrigerant expands.

With regard to the design of the temperature control system, no specific information has been given about the at least one compressor stage in connection with the previous explanation of the solution according to the invention.

With a simply designed solution, it is possible to operate the refrigerant circuit with one compressor stage.

However, another advantageous solution provides that the refrigerant circuit has a first compressor stage and at least one second compressor stage working in series with it, and that the first compressor stage compresses the refrigerant from a suction pressure corresponding to the expansion pressure in the respective heat exchanger to an intermediate pressure and that the second compressor stage compresses the refrigerant from the intermediate pressure to high pressure.

If a single compressor stage is provided, this is realized by a refrigerant compressor. If two or more compressor stages are provided, these can be realized both by a multi-stage refrigerant compressor and by multiple refrigerant compressors.

It is particularly favorable if the first compressor stage feeds the refrigerant to a heat exchanger to heat the refrigerant before it enters the second compressor stage, in order to achieve a sufficiently low temperature of the refrigerant before it enters the second compressor stage.

Furthermore, a connecting line is advantageously provided in the refrigerant circuit with a control valve controlled in particular by a controller of the refrigerant circuit, with which gaseous refrigerant compressed from the first compressor stage to an intermediate pressure can be fed to a suction line of the first refrigerant compressor stage.

Such a connecting line has the advantage that when a very small flow of refrigerant flows through the respectively active heat exchanger, it can be used to maintain a sufficiently large flow of refrigerant through the first compressor stage.

Furthermore, it is preferably provided that the refrigerant compressed to high pressure first undergoes a desuperheating in a heat exchanger and subsequently undergoes liquefaction in a heat exchanger.

As a result, a very efficient liquefaction of the refrigerant can be achieved in an advantageous manner, since the heat removal can take place in a heat exchanger cooled with ambient air, while the liquefaction takes place in a heat exchanger which may be cooled by an additional refrigeration unit.

Furthermore, it is expediently provided that the refrigerant circuit supplies the liquefied refrigerant either to the first heat exchanger or to the second heat exchanger for absorbing heat. A further advantageous solution of the temperature control system according to the invention provides that after the high-pressure side heat exchanger that liquefies the refrigerant, the refrigerant is expanded by an expansion element to a medium pressure and enters a medium-pressure separator, in which the gaseous and liquid phases are separated and that a supply the liquid phase to the first or second heat exchanger taking up heat from the medium.

This solution has the advantage that by reducing the pressure of the liquefied refrigerant to the medium pressure, the control of the first or second heat exchanger can be carried out with increased precision and efficiency.

In order to be able to maintain a defined medium pressure in the medium-pressure separator, it is preferably provided that at least one compressor stage is assigned a connecting line with a control valve, which is controlled in particular by a controller of the refrigerant circuit, with which the gaseous phase collecting in the medium-pressure separator is fed to a suction line of the at least one Compressor stage can be supplied, so that on the one hand a suction-side cooling of the respective compressor stage can take place and on the other hand the medium pressure in the medium-pressure separator can be maintained in a defined manner.

A further advantageous solution provides that at least one compressor stage is assigned a connecting line with a control valve controlled in particular by a controller of the refrigerant circuit, with which gaseous refrigerant compressed to high pressure can be fed to a suction line of the at least one compressor stage. This connecting line has the advantage that when a low cooling capacity is required in the heat exchangers and the refrigerant flow through the respective active heat exchanger is very low, a sufficiently large refrigerant flow can nevertheless be maintained through the respective refrigerant compressor stage.

Furthermore, it is preferably provided that at least one compressor stage in the refrigerant circuit is assigned a connecting line with a control valve controlled in particular by a controller of the refrigerant circuit, with which liquid refrigerant compressed to high pressure can be fed to a suction line of the at least one compressor stage.

This solution has the advantage that it makes it possible to reduce the temperature of the refrigerant sucked in through the suction line in a simple manner in order to avoid overheating of the compressor stage.

Furthermore, it is preferably provided that at least one compressor stage is assigned a connecting line with a control valve controlled in particular by a controller of the refrigerant circuit, with which compressed liquid refrigerant at medium pressure can be fed to a suction line of the at least one compressor stage.

With regard to the routing of the refrigerant emerging from the second heat exchanger, which due to the conventional expansion is at a higher pressure level than the refrigerant expanded in the first heat exchanger, it is preferably provided that the second heat exchanger is connected on the outlet side to a suction line of the first compressor stage or the second compressor stage, wherein a connection to the second compressor stage offers an efficiency advantage at a high expansion pressure in the second heat exchanger. In addition, an advantageous solution provides that a container for receiving gaseous refrigerant under high pressure is provided in the refrigerant circuit, in which this can be temporarily stored in order to temporarily withdraw refrigerant from the refrigerant circuit.

In particular, the temporarily stored refrigerant, which is temporarily stored at high pressure, can be fed to a suction line of a compressor stage.

In addition, it is preferably provided that a lubricant separator for separating lubricant is provided in the refrigerant circuit following the respective compressor stage.

The lubricant separator is expediently provided with a return for the separated refrigerant to the respective compressor stage.

The invention also relates to a temperature testing or temperature simulation system which is characterized in that it comprises a temperature control system according to one of the preceding claims and that a heater is also provided with which the medium can be heated in addition to cooling to implement temperature cycles.

In addition, the invention relates to a method for operating a temperature control system, comprising a medium to be temperature-controlled, with which at least one heat exchanger interacts to absorb heat from the medium, and a refrigerant circuit, which supplies the at least one heat exchanger with refrigerant for expansion and for this purpose comprises at least one compressor stage compressing refrigerant expanded in the heat exchanger and a heat exchanger dissipating heat from the compressed refrigerant as well as a control valve for controlling the mass flow of the compressed refrigerant to the at least one heat exchanger for absorbing heat.

Methods of this type are also known from the prior art, with these also having the problem of achieving temperatures below approximately 223 K in an efficient manner.

In a method of the type described above, this object is achieved according to the invention in that, in the first heat exchanger, the refrigerant is fed to a refrigerant distributor following a feed line and, proceeding from there, is fed through at least one nozzle element that limits the mass flow to at least one heat exchanger channel and expands there.

In this method, it is provided in particular that the refrigerant is supplied to the refrigerant distributor at a pressure above a triple point of the refrigerant.

In addition, it is preferably provided that the coolant is supplied to the coolant distributor in a supercritical state of the latter.

As an alternative to this, it is provided that the refrigerant is supplied to the refrigerant distributor in a liquid and a gaseous phase.

As an alternative to this, it can also be provided that the refrigerant is supplied to the refrigerant distributor in the liquid phase. In addition, it is provided that the refrigerant is supplied to the nozzle element at such a pressure and is guided in it that there is no expansion of the refrigerant to a pressure below the triple point of the same, so that it can be avoided in particular that in the nozzle element forms a solid phase of the refrigerant and possibly causes a partial blockage in this.

Furthermore, in order to reach the low temperatures, it is provided that the refrigerant in the heat exchanger channel adjoining the nozzle element is expanded to a pressure in the sublimation region of the refrigerant, i.e. part of the refrigerant in the heat exchanger channel changes into the gas phase and part of the refrigerant to the solid phase and from this to the gas phase by sublimation, whereby the desired low temperatures below approximately 223 K can be achieved.

Furthermore, in the solution according to the invention, it is advantageously provided that a pressure of the refrigerant which is below the triple point of the refrigerant is maintained in the at least one heat exchanger channel.

A further expedient solution provides that the refrigerant in the at least one heat exchanger channel is kept at a pressure corresponding to a sublimation pressure of the refrigerant.

The above-mentioned object is achieved alternatively or additionally in a method of the type described above according to the invention in that a first and a second heat exchanger interact with the medium, that the first heat exchanger is used to cool the medium to temperatures of less than approximately 223 K and that the second heat exchanger is used to cool the medium to temperatures above approximately 223 K and that the refrigerant circuit is operated in such a way that it feeds either refrigerant into the first heat exchanger or into the second heat exchanger.

The advantage of this solution can therefore be seen in the fact that the desired temperatures below approximately 223 K can be achieved easily and with high efficiency by using the first heat exchanger, and the temperatures above approximately 223 K can also be achieved with high efficiency using the second heat exchanger .

A particularly favorable solution provides that the refrigerant circuit has a supply line to the first heat exchanger and a supply line to the second heat exchanger and that in each of the supply lines the mass flow supplied to the respective heat exchanger is controlled by a controller of the refrigerant circuit.

In this way, a change in the operation of the first and the second heat exchanger can be implemented in a simple manner and, moreover, operation of the refrigerant circuit can also be controlled in a simple manner.

In particular, it is provided here that, depending on the required temperature of the medium to be cooled provided in the room, compressed refrigerant from the refrigerant circuit is supplied in a temperature-controlled manner either to the second heat exchanger or to the first heat exchanger.

In addition, no further details have been given in connection with the realization of the second heat exchanger.

An advantageous solution provides that the refrigerant expands in the supply line to the second heat exchanger, so that already expanded refrigerant enters the second heat exchanger. In addition, it is preferably provided that the second heat exchanger is operated in such a way that the refrigerant expands in it at a pressure above the sublimation range of the refrigerant, ie conventional expansion of the refrigerant takes place starting from an expansion pressure above a triple point of the refrigerant.

In particular, the second heat exchanger is designed as a conventional heat exchanger.

In addition, the solution according to the invention advantageously provides that a first compressor stage and at least one second compressor stage working in series with it are provided in the refrigerant circuit, that the refrigerant is compressed from a suction pressure to an intermediate pressure with the first compressor stage and that with the second Compressor stage, the refrigerant is compressed from the intermediate pressure to high pressure.

In order to be able to carry out the compression with the compressor stages as efficiently as possible, it is preferably provided that the refrigerant from the first compressor stage is fed to a heat exchanger to heat the refrigerant before it enters the second compressor stage.

In order to be able to maintain a sufficiently large flow of refrigerant through the first compressor stage, particularly when the refrigerating capacity in the first and second heat exchangers is reduced, it is preferably provided that in the refrigerant circuit, gaseous refrigerant compressed by the first compressor stage to an intermediate pressure is fed to the first compressor stage on the suction side as required. In addition, when the refrigerant circuit according to the invention is operated, it is preferably provided that the refrigerant compressed to high pressure is first deheated in a heat exchanger and then liquefied in a heat exchanger, so that the refrigerant compressed to high pressure can be efficiently cooled, in particular since the deheating can take place against ambient air, so that a refrigeration circuit may also be required only for liquefaction.

For the operation of the first or second heat exchanger, it is also preferably provided that the liquefied refrigerant, after liquefaction, is fed to either the first heat exchanger or the second heat exchanger in a temperature-controlled manner to absorb heat from the medium, with the temperature control being based on the required temperature for the medium .

A further advantageous solution provides that after the high-pressure side has been liquefied, the refrigerant is expanded to a medium pressure and collected in a medium-pressure separator, in which the gaseous and liquid phases are separated and that the liquid phase absorbs heat from the medium first or second Heat exchanger is supplied temperature-controlled, the temperature in this case also being based on the temperature required for the medium.

In order to be able to maintain a defined mean pressure in the medium-pressure separator, it is preferably provided that at least one compressor stage is supplied with a gaseous phase collecting in the medium-pressure separator on the suction side in a medium-pressure-controlled manner, i.e. the supply of the gaseous phase to the respective suction side of the compressor stage is controlled by a controller or regulation for the medium pressure, which is detected, for example, in the medium-pressure separator. A further advantageous solution provides that gaseous refrigerant compressed to high pressure is fed to at least one compressor stage on the suction side as required, with this serving in particular to ensure that a sufficiently large amount of refrigerant is available in the case in which a relatively low cooling capacity is required in the first or second heat exchanger To provide compression of the compressor stage.

In addition, an advantageous solution provides that liquid refrigerant compressed to high pressure is fed to at least one compressor stage on the suction side in a demand-controlled manner.

This solution also serves to ensure a sufficiently low temperature of the refrigerant on the suction side of the compressor stage in order to prevent the compressor stage from overheating.

In addition, an advantageous solution provides that at least one compressor stage is supplied with compressed liquid refrigerant at medium pressure on the suction side in a demand-controlled manner.

A further advantageous solution provides that expanded refrigerant from the second heat exchanger is fed to the first compressor stage or the second compressor stage on the suction side in order to achieve the most efficient possible compression of the refrigerant, which expands at a higher pressure, in the second heat exchanger.

In order to be able to advantageously control the amount of refrigerant in the refrigerant circuit, provision is preferably made for gaseous refrigerant under high pressure to be temporarily stored in a container in a demand-controlled manner in the refrigerant circuit, so that refrigerant can thereby be withdrawn from the refrigerant circuit. In order to be able to supply this refrigerant to the refrigerant circuit again, it is expediently provided that the intermediately stored refrigerant is supplied to a compressor stage on the suction side in a demand-controlled manner.

In order to keep the circulation of lubricant components in the refrigerant as low as possible in the refrigerant circuit according to the invention, provision is preferably made for lubricant to be separated in the refrigerant circuit after the respective compressor stage.

The lubricant separated in the process can in particular be returned to the respective compressor stage.

The invention also relates to a method for operating a temperature testing or temperature simulation system, the method being carried out according to one of the above features of the temperature control system and the medium being additionally heated by a heater provided in the room in order to implement temperature cycles.

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

1. Temperature control system (10), comprising a medium (14) to be temperature-controlled, with which at least one heat exchanger (32, 34) for absorbing heat from the medium (14) interacts, and a refrigerant circuit (30) which the at least one Heat exchanger (32, 34) supplies refrigerant for expansion, and for this purpose at least one compressor stage (102) compressing expanded refrigerant in the heat exchanger (32, 34) and a heat exchanger (122, 126) dissipating heat from the compressed refrigerant and a control valve (82, 84) for controlling the mass flow of the compressed refrigerant for at least one Heat exchanger (32, 34) for absorbing heat, a first heat exchanger (32) being designed such that in the first heat exchanger (32) following a supply line (33), the refrigerant enters a refrigerant distributor (36) and from this proceeding through at least one nozzle element (42) limiting the mass flow, enters at least one heat exchanger channel (44) and expands therein.

2. Temperature control system according to embodiment 1, wherein the refrigerant in the heat exchanger channel (44) adjoining the nozzle element (42) expands to a pressure which is below the triple point of the refrigerant.

3. Temperature control system (10) according to the preamble of embodiment 1 or according to one of the preceding embodiments, wherein a first (32) and a second heat exchanger (34) interact with the medium (14) so that the first heat exchanger (32) for cooling the Medium (14) is designed for temperatures of less than approximately 223 K, that the second heat exchanger (34) is designed to cool the medium to temperatures above approximately 223 K and that the refrigerant circuit (30) is designed in such a way that, during operation, it either Feeds refrigerant into the first heat exchanger (32) or into the second heat exchanger (34).

4. Temperature control system according to embodiment 3, wherein the refrigerant circuit (30) has a feed line (33) to the first heat exchanger (32) and a feed line (35) to the second heat exchanger (34), and that in each of the feed lines (33, 35 ) a control valve (82, 84) controlled by a controller (86) of the refrigerant circuit (30) is provided for controlling the mass flow fed to the respective heat exchanger (32, 34). 5. Temperature control system according to embodiment 3 or 4, wherein a controller (86) supplies compressed refrigerant to either the second heat exchanger (34) or the first heat exchanger (32), depending on the required temperature of the medium (14) to be cooled in the space (12). temperature-controlled to the refrigerant circuit (30).

6. Temperature control system according to one of the preceding embodiments, wherein an expansion element (84) is arranged in the supply line (35) to the second heat exchanger (34).

7. Temperature control system according to one of the preceding embodiments, wherein in the second heat exchanger (34) there is an expansion of the refrigerant at a pressure above the sublimation range of the refrigerant.

8. Temperature control system according to one of the preceding embodiments, wherein in the second heat exchanger (34) channels in which the supplied refrigerant evaporates, extend from a supply line (35) to a return line (74) of the second heat exchanger (34).

9. Temperature control system according to the preamble of embodiment 1 or according to one of the preceding embodiments, wherein in the refrigerant circuit (30) a first compressor stage (102a) and at least one working in series with this second compressor stage (102b) are provided and that the first compressor stage ( 102a) compresses the refrigerant from a suction pressure to an intermediate pressure and that the second compressor stage (102b) compresses the refrigerant from the intermediate pressure to high pressure.

10. Temperature control system according to embodiment 9, wherein the first compressor stage (102a) feeds the refrigerant to a heat exchanger (142) to heat the refrigerant before it enters the second compressor stage (102b). 11. Temperature control system according to one of the preceding embodiments, wherein a connecting line (152) with a control valve (154) is provided in the refrigerant circuit (30), with which from the first compressor stage (102a) compressed to intermediate pressure gaseous refrigerant of a suction line of the first refrigerant compressor stage ( 102a) can be supplied.

12. Temperature control system according to one of the preceding embodiments, wherein the refrigerant compressed to high pressure first undergoes cooling in a heat exchanger (122) and subsequently undergoes liquefaction in a heat exchanger (126).

13. Temperature control system according to embodiment 12, wherein the refrigerant circuit (30) supplies the liquefied refrigerant either to the first heat exchanger (32) or to the second heat exchanger (34) for absorbing heat.

14. Temperature control system according to the preamble of embodiment 1 or according to one of the preceding embodiments, wherein the refrigerant after the high-pressure side, the refrigerant liquefying heat exchanger (126) is expanded by an expansion element (162) to a medium pressure and enters a medium-pressure separator (164). , in which a separation of gaseous (168) and liquid phase (166) takes place, and that the liquid phase (166) is supplied to the first or second heat exchanger (32, 34) absorbing heat from the medium (14).

15. Temperature control system according to embodiment 14, wherein at least one compressor stage (102, 102a, 102b) is assigned a connecting line (172) with a control valve (174), with which the gaseous phase (168) collecting in the medium-pressure separator (164) leads to a suction line (92, 92a, 92) to which at least one compressor stage (102, 102a, 102b) can be fed. 16. Temperature control system according to one of the preceding embodiments, wherein at least one compressor stage (102a, 102a, 102b) is assigned a connecting line (132) with a control valve (134), with which gaseous refrigerant compressed to high pressure is fed to a suction line (92, 92a, 92b) the at least one compressor stage (102, 102a, 102b) can be supplied.

17. Temperature control system according to one of the preceding embodiments, wherein at least one compressor stage (102, 102a, 102b) in the refrigerant circuit (30) is assigned a connecting line (136) with a control valve (138), with which liquid refrigerant compressed to high pressure is fed to a suction line ( 92, 92a, 92b) which can be fed to the at least one compressor stage (102).

18. Temperature control system according to one of the preceding embodiments, wherein at least one compressor stage (102, 102a, 102b) is assigned a connecting line (176) with a control valve (178), with which compressed liquid refrigerant at medium pressure is fed to a suction line (92, 92a, 92b) the at least one compressor stage (102, 102a, 102b) can be supplied.

19. Temperature control system according to one of the preceding embodiments, wherein the second heat exchanger (34) is connected on the output side to a suction line (92a, 92b) of the first compressor stage (102a) or the second compressor stage (102b).

20. Temperature control system according to the preamble of embodiment 1 or according to one of the preceding embodiments, wherein in the refrigerant circuit (30) a container (142) for receiving gaseous refrigerant under high pressure is provided, in which this can be temporarily stored to the refrigerant circuit ( 30) To withdraw refrigerant temporarily. 21. Temperature control system according to embodiment 20, wherein the intermediately stored refrigerant can be fed to a suction line (92) of a compressor stage (102).

22. Temperature control system according to one of the preceding embodiments, wherein a lubricant separator (114) for separating lubricant is provided following the respective compressor stage (102) in the refrigerant circuit (30).

23. Temperature control system according to embodiment 22, wherein the lubricant separator (114) has a return (116) for the separated lubricant to the respective compressor stage (102).

24. Temperature testing system or temperature simulation system, this having a temperature control system (10) according to one of the preceding embodiments and that this additionally has a heater (180) for heating the medium (14).

25. Method for operating a temperature control system (10), comprising a medium (14) to be temperature-controlled, with which at least one heat exchanger (32, 34) for absorbing heat from the medium (14) interacts, and a refrigerant circuit (30), which supplies the at least one heat exchanger (32, 34) with refrigerant for expansion and for this purpose at least one compressor stage (102) compressing expanded refrigerant in the heat exchanger (32, 34) and a heat exchanger (122, 126) dissipating heat from the compressed refrigerant and a control valve (82, 84) for controlling the mass flow of the compressed refrigerant to the at least one heat exchanger (32, 34) for absorbing heat, with the refrigerant being fed to a refrigerant distributor (36) following a supply line (33) in the first heat exchanger (32). and starting from there through at least one nozzle element (42) limiting the mass flow, it is fed to at least one heat exchanger channel (44). t becomes and expands in this. 26. The method of embodiment 25, wherein the refrigerant is supplied to the refrigerant manifold (36) at a pressure lying above a triple point of the refrigerant.

27. The method according to embodiment 26, wherein the refrigerant is supplied to the refrigerant manifold (36) in a supercritical state thereof.

28. The method according to embodiment 26, wherein the refrigerant having a liquid phase and a gaseous phase is supplied to the refrigerant distributor (36).

29. The method of embodiment 26, wherein the refrigerant is supplied in the liquid phase to the refrigerant manifold (36).

30. The method according to any one of embodiments 25 to 29, wherein the refrigerant is fed to and guided in the nozzle element (42) at such a pressure that there is no expansion of the refrigerant at a pressure below the triple point thereof.

31. The method according to any one of embodiments 25 to 30, wherein the refrigerant in the heat exchanger channel (44) adjoining the nozzle element (42) is expanded by sublimation.

32. The method according to embodiment 31, wherein a pressure of the refrigerant which is below the triple point of the refrigerant is maintained in the at least one heat exchanger channel (44).

33. The method according to embodiment 31 or 32, wherein the refrigerant in the at least one heat exchanger channel (44) is kept at a pressure corresponding to a sublimation pressure of the refrigerant. 34. The method according to the preamble of embodiment 25 or according to one of embodiments 25 to 33, wherein a first (32) and a second heat exchanger (34) interact with the medium (14), that the first heat exchanger (32) for cooling the medium (14) at temperatures less than about 223 K, that the second heat exchanger

(34) is used to cool the medium to temperatures above approximately 223 K and that the refrigerant circuit (30) is operated in such a way that it feeds refrigerant either into the first heat exchanger (32) or into the second heat exchanger (34).

35. The method according to embodiment 34, wherein the refrigerant circuit (30) has a feed line (33) to the first heat exchanger (32) and a feed line

(35) to the second heat exchanger (34) and that in each of the feed lines (33, 35) the mass flow fed to the respective heat exchanger (32, 34) is controlled by a controller (86) of the refrigerant circuit (30).

36. The method according to embodiment 34 or 35, wherein, depending on the required temperature of the medium (14) to be cooled provided in the space (12), either the second heat exchanger (34) or the first heat exchanger (32) supplies compressed refrigerant from the refrigerant circuit (30) temperature-controlled.

37. The method according to any one of embodiments 34 to 36, wherein the refrigerant is expanded in the feed line (35) to the second heat exchanger (34).

38. The method according to any one of embodiments 34 to 37, wherein the second heat exchanger (34) is operated in such a way that the refrigerant expands therein at a pressure above the sublimation range of the refrigerant. 39. The method according to any one of embodiments 34 to 38, wherein the second heat exchanger (34) is designed as a conventional heat exchanger (34), in particular as an evaporator.

40. The method according to the preamble of embodiment 25 or according to one of embodiments 25 to 39, wherein in the refrigerant circuit (30) a first compressor stage (102a) and at least one working in series with this second compressor stage (102b) are provided that with the first compressor stage (102a) the refrigerant is compressed from a suction pressure to an intermediate pressure and that with the second compressor stage (102b) the refrigerant is compressed from the intermediate pressure to high pressure.

41. The method according to embodiment 40, wherein the refrigerant from the first compressor stage (102a) is fed to a heat exchanger (142) to heat the refrigerant before it enters the second compressor stage (102b).

42. The method according to one of the embodiments 25 to 41, wherein in the refrigerant circuit (30) from the first compressor stage (102a) compressed gaseous refrigerant to intermediate pressure is supplied to the latter on the suction side as required.

43. The method according to one of embodiments 25 to 42, wherein the refrigerant compressed to high pressure is first deheated in a heat exchanger (122) and is subsequently liquefied in a heat exchanger (126).

44. The method according to embodiment 43, wherein the refrigerant circuit (30), after liquefaction, the liquefied refrigerant is supplied under temperature control to either the first heat exchanger (32) or the second heat exchanger (34) to absorb heat from the medium (14). 45. The method according to the preamble of embodiment 25 or according to one of embodiments 25 to 44, wherein the refrigerant is expanded to a medium pressure after the high-pressure side, liquefaction and is collected in a medium-pressure separator (164), in which a separation of gaseous (168) and liquid phase (166), and that the liquid phase is fed to the first or second heat exchanger (32, 34) absorbing heat from the medium (14) in a temperature-controlled manner.

46. The method according to embodiment 45, wherein a gaseous phase (168) collecting in the medium-pressure separator is fed to at least one compressor stage (102, 102a, 102b) on the suction side in a medium-pressure-controlled manner.

47. The method according to any one of embodiments 25 to 46, wherein at least one compressor stage (102a, 102a, 102b) is supplied with gaseous refrigerant compressed to high pressure on the suction side in a demand-controlled manner.

48. The method according to any one of embodiments 25 to 47, wherein at least one compressor stage (102, 102a, 102b) is supplied with liquid refrigerant compressed to high pressure on the suction side in a demand-controlled manner.

49. The method according to one of embodiments 25 to 48, wherein compressed liquid refrigerant at medium pressure is supplied to at least one compressor stage (102, 102a, 102b) on the suction side in a demand-controlled manner.

50. The method according to any one of embodiments 25 to 49, wherein expanded refrigerant from the second heat exchanger (34) is fed to the first compressor stage (102a) or the second compressor stage (102b) on the suction side.

51. The method according to the preamble of embodiment 25 or according to one of embodiments 25 to 50, wherein in the refrigerant circuit (30) gaseous refrigerant under high pressure is temporarily stored in a container (142) as required. 52. The method according to embodiment 51, wherein the intermediately stored refrigerant is supplied to a compressor stage (102) on the suction side in a demand-controlled manner.

53. The method according to any one of embodiments 25 to 52, wherein in the refrigerant circuit (30) the respective compressor stage (102) is followed by a separation of lubricant.

54. The method of embodiment 53, wherein the separated lubricant is recycled to the respective compressor stage (102).

55. Method for operating a temperature testing system or a temperature simulation system, this being carried out according to a method according to one of the embodiments 25 to 54 and additionally the medium (14) is heated by a heater (180) in a demand-controlled manner.

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 first exemplary embodiment of a temperature control system according to the invention;

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

3 shows a second exemplary embodiment of a temperature control system according to the invention; 4 shows a third exemplary embodiment of a temperature control system according to the invention;

5 shows a fourth exemplary embodiment of a temperature control system according to the invention;

6 shows a fifth exemplary embodiment of a temperature control system according to the invention;

7 shows a sixth exemplary embodiment of a temperature control system according to the invention;

8 shows a seventh exemplary embodiment of a temperature control system according to the invention;

9 shows an eighth embodiment of a temperature control system according to the invention and

10 shows a ninth exemplary embodiment of a temperature control system according to the invention.

A first exemplary embodiment of a temperature control system according to the invention, denoted as a whole by 10, is used for tempering a thermally insulated space, denoted as a whole by 12, in which a medium 14 to be tempered is arranged.

This medium 14 can be a gas, in particular air, for example, it being possible for the gas to be circulated in the space 12 by a blower, for example, in order to temper an object 18 arranged in the space 12 , for example. In an expedient solution, the space 12 is arranged in a thermally insulated chamber 20 which represents, for example, a test chamber of a temperature test system or an environmental simulation system.

However, it is also possible for the medium 14 to be a liquid or phase-changing heat transport medium, for example a brine, or a gaseous medium with which any other objects can be cooled or tempered, for example by means of a heat exchanger.

To cool the medium 14, a refrigerant circuit designated as a whole by 30 is provided, in which a first heat exchanger 32 and a second heat exchanger 34 are arranged, in which a refrigerant circulated in the refrigerant circuit 30 expands to absorb heat from the medium 14.

As shown in Fig. 2, the first heat exchanger 32 comprises a feed line 33 for the refrigerant, from which the refrigerant enters a refrigerant distributor, designated as a whole with 36, and is supplied to a plurality of nozzle elements 42, in particular designed as nozzle channels, in an interior space of the latter , via which the refrigerant enters heat exchanger channels 44 of heat exchanger elements 46, expands in these and leaves the heat exchanger channels 44 after passing through them and enters a refrigerant collector 52, which discharges the refrigerant into a return line 54.

The nozzle elements 42 are designed, for example with regard to their cross-sectional area, 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. This means that after the refrigerant has exited from the nozzle channels 42 into the respective heat exchanger channels 44 , the expansion of the refrigerant leading to the absorption of heat takes place.

In order to achieve this, particularly when using CO2 as the refrigerant, the refrigerant is supplied via the supply line 33 to the refrigerant distributor 36 and there to the nozzle elements 42 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 respective nozzle element 42 is then reduced, but at the transition from the nozzle element 42 into the heat exchanger channel 44 it is preferably still above the triple point of the refrigerant, in the case of CO2 above the triple point of CO2, so that essentially sublimation of the refrigerant in the nozzle passage 42 is prevented.

The pressure on the outlet side of the nozzle channel is preferably in the range greater than 6 bar, for example in the range from approximately 6 bar to approximately 40 bar.

The pressure of the refrigerant is therefore only below the pressure of the refrigerant in the triple point in the heat exchanger channel 44, 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 path through the heat exchanger channel 44 in the respective heat exchanger body 46 completely changes into the gaseous state and in the process can absorb heat from a heat flow 58 flowing around the heat exchanger body 46 . After passing through the heat exchanger body 46 , gaseous refrigerant is preferably present in the refrigerant collector 52 , which emerges from the heat exchanger channel 44 , is collected by the refrigerant collector 52 and is fed to the return line 54 .

In particular, the nozzle elements 42 have a limiting effect on the mass flow of the refrigerant if they have a cross-sectional area which, based on a transition into a subsequent heat exchanger channel 44, is at most 0.05 mm ² or less, preferably at most 0.01 mm ² or less better is at most 0.05 mm ² or less.

If several nozzle elements 42 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 44, it is preferably provided that they have a cross-sectional area of less than 8 mm ² , better less than 4 mm ² and even better less than 1.5 mm ² in order to obtain optimum heat transfer, particularly with the sublimating refrigerant .

The second heat exchanger 34 is designed as a conventional heat exchanger, for example as an evaporator, which means that the refrigerant supplied via a supply line 35 in the heat exchanger 34 does not experience any mass flow limitation that significantly influences the expansion of the refrigerant and thus its function.

Thus, the second heat exchanger 34 represents a conventional refrigerant heat exchanger operating at pressures above the triple point. As shown in Fig. 1, the first heat exchanger 32 and the second heat exchanger 34 are connected in parallel in the refrigerant circuit 30, with a control valve 82 or 84 being arranged in the supply lines 33 or 35 to the first heat exchanger 32 or the second heat exchanger 34, which once serves to supply coolant to either the first heat exchanger 32 or the second heat exchanger 34 by means of a controller 86 .

Furthermore, the controller 86 is able to control the refrigerant flow to the respective heat exchanger 32 or 34 quantitatively, for example by pulse operation.

In addition, an expansion element is to be provided in the supply line 35 of the second heat exchanger 34, but this can also be formed, for example, by the control valve 84 with appropriate activation by the controller 86, in order to bring the refrigerant to the inlet side of the second heat exchanger 34 at a pressure intended for expansion to feed

Also provided in the return line 74 of the second heat exchanger 34 is a check valve, designated as a whole by 88 , which prevents coolant from flowing back into the second heat exchanger 34 .

In the refrigerant circuit 30, the return lines 54 and 74 from the two heat exchangers 32 and 34 are connected to a suction line 92 of a compressor stage 102, so that the expanded refrigerant either from the first heat exchanger 32 or from the second heat exchanger 34 through the refrigerant compressor stage 102 from the in The suction pressure present in the suction line 92 is compressed to a high pressure present in a high-pressure line 112 on the output side of the compressor stage. The first compressor stage 102 is implemented, for example, by a single-stage refrigerant compressor.

In order to collect lubricant discharged from first compressor stage 102 into high-pressure line 112, a lubricant separator 114 is preferably provided in high-pressure line 112, which leads the separated lubricant back to first compressor stage 102 via a return line 116.

Also provided in the high-pressure line 112 is a heat exchanger 122 on the high-pressure side, which is used to heat the compressed refrigerant and emits a flow of heat 124 to the environment, preferably ambient air.

Heat exchanger 122 is followed by a further heat exchanger 126, which is used to liquefy the desuperheated refrigerant compressed to high pressure, which is then fed via a supply line 128 to the supply lines 33 or 35 of the heat exchangers 32 or 34, which are supplied in the manner described by of the controller 86 can be operated.

In order to be able to operate the refrigerant circuit 30 optimally, particularly when only a small mass flow of refrigerant is required for the first heat exchanger 32 or the second heat exchanger 34, a first connecting line 132 with a control valve 134 arranged in it is provided in the refrigerant circuit compressed, gaseous and desuperheated refrigerant branches off between the desheating heat exchanger 122 and the condensing heat exchanger 126 and the suction line 92 of the compression stage 102 can perform in order to operate the compression stage with a sufficient mass flow of refrigerant. Furthermore, a second connecting line 136 is provided with a control valve 138 arranged in it, with which there is the possibility of removing liquid refrigerant from the supply line 128 and feeding it to the suction line 92 in order to prevent the compressor stage 102 from overheating on the inlet side.

Furthermore, in order to optimize the amount of refrigerant available, a tank 142 is provided for holding gaseous, in particular desuperheated, refrigerant between heat exchanger 122 and heat exchanger 126, with this taking place via a control valve 144 arranged on the inlet side of tank 142 for controlling the inflow and on the outlet side of the container 142, a control valve 146 is provided, which is able, if necessary in the refrigerant circuit, to release refrigerant from the container into the suction line 92.

In a second exemplary embodiment of a temperature control system 10′ according to the invention, shown in FIG. 3, those elements which are identical to those of the first exemplary embodiment are provided with identical reference symbols, so that with regard to the description of the same, reference can be made in full to the explanations relating to the first exemplary embodiment .

In contrast to the first exemplary embodiment, the refrigerant circuit 30' includes not only a compressor stage 102, but a first compressor stage 102a and a second compressor stage 102b, with each of the compressor stages being arranged downstream of a lubricant separator 114, as was described in connection with the first exemplary embodiment.

The first and the second compressor stage 102a and 102b can be realized either by a two-stage refrigerant compressor or by two refrigerant compressors. However, more than two compressor stages are also conceivable.

Furthermore, downstream of the lubricant separator 114 of the first compressor stage 102a, a heat exchanger 142 is provided, with which the refrigerant compressed by the first compressor stage 102a to an intermediate pressure is cooled, which is then in turn compressed by the second compressor stage 102b from the intermediate pressure to high pressure.

Furthermore, a connecting line 132a or 132b with the respective control valve 134a or 134b is provided for each of the compressor stages 102a and 102b, which makes it possible to supply gaseous refrigerant compressed to high pressure to the respective suction line 92a or 92b.

In addition, a connecting line 136a or 136b with the respective control valve 138a or 138b is provided, which makes it possible to supply liquid or supercritical refrigerant under high pressure to the respective suction line 92a or 92b of the respective compressor stage 102a or 102b.

In addition, a connecting line 152 with a control valve 154 is also provided, which makes it possible to supply gaseous refrigerant, compressed to intermediate pressure and deheated by the heat exchanger 142, to the suction line 92a and thus creating a bypass to the first compressor stage 102a.

In a third exemplary embodiment of a temperature control system 10" according to the invention, shown in Fig. 4, those elements which are identical to those of one of the preceding exemplary embodiments are provided with the same reference symbols, so that the description of the same can be fully referred to the statements relating to the preceding Embodiments can be referred. In contrast to the second exemplary embodiment, the third exemplary embodiment provides that the return line 74 of the second heat exchanger 34 is not connected to the suction line 92a of the first refrigerant compressor stage 102a, but to the suction line 92b of the second compressor stage 102b, if it is assumed that the expansion pressure in the second heat exchanger 34 is higher than that of the first heat exchanger 32, so that this solution works more efficiently.

In a fourth exemplary embodiment of a temperature control system 10"' according to the invention, shown in FIG. 5, in particular those elements which are identical to those of the preceding exemplary embodiments are provided with the same reference numerals, so that with regard to the description of the same, reference is made to the statements relating to the preceding exemplary embodiments in full can be referred to.

In contrast to the preceding exemplary embodiments, in particular the first exemplary embodiment, an expansion element 162 is provided in the temperature control system 10"' in the supply line 128 after the heat exchanger 126 that liquefies the refrigerant compressed to high pressure, which expands the liquid or supercritical refrigerant to medium pressure and a medium-pressure separator 164, in which a bath 166 of liquid refrigerant and a gas bubble 168 of gaseous refrigerant are then formed, with the liquid refrigerant from the bath 166 being fed to the feed lines 33 and 35 to the heat exchangers 32 and 34, respectively.

Furthermore, by means of a connecting line 172 provided with a control valve 174, gaseous refrigerant from the gas bubble 168 is supplied to the suction line 92 of the compressor stage 102. The expansion of the liquid refrigerant to medium pressure provided in this exemplary embodiment has the advantage that the control quality during operation of the heat exchangers 32 and 94 can be improved by means of the control valves 82 and 84, since the pressure difference to be set is lower, particularly when using CO2 as the refrigerant and resulting in efficiency gains.

In a fifth exemplary embodiment of a temperature control system 10"" according to the invention, shown in FIG the comments on the fourth exemplary embodiment can be referred to.

In contrast to the fourth exemplary embodiment, in addition to the connecting line 172 with the control valve 174, which supplies gaseous refrigerant from the gas bladder 168 to the suction line 92 of the compressor stage 102, there is also a connecting line 176 which also has a control valve 178 and is capable of supplying liquid refrigerant branch off from the bath 166, which is fed to the feed lines 33 and 35, and feed it to the suction line 92 of the compression stage 102.

This connecting line 176 creates the possibility, with a further degree of freedom, of influencing the temperature of the coolant in the suction line 92 to the compressor stage 102 in a way that is optimal for the compressor stage 102 . In a sixth exemplary embodiment of a temperature control system according to the invention shown in FIG. 7, those elements which are identical to those of the preceding exemplary embodiments are provided with the same reference symbols, so that reference can be made to the explanations relating to the preceding exemplary embodiments with regard to the description of the same.

In particular, in the sixth exemplary embodiment according to FIG. 7, two compressor stages 102a and 102b with the lubricant separators 114 are provided.

In addition, in the sixth embodiment, the connection pipe 132a with the control valve 134a and the connection pipe 132b with the control valve 134b are provided in the same manner as in the second and third embodiments.

Furthermore, the connecting lines 136a with the control valves and 136b and the associated control valves 138a and 138b are provided, with which gaseous refrigerant under high pressure can be fed to the suction lines 92a and 92b.

Furthermore, in this exemplary embodiment it is provided that the gaseous refrigerant from the gas bladder 168 is connected via the connecting line 172a to the suction line 92a of the first compressor stage 102a, controlled by the control valve 174a, and at the same time a connecting line 172b is provided with a control valve 174b. which gaseous refrigerant from the gas bubble 168 of the suction line 92b of the second compressor stage 102b can be fed.

Furthermore, in the sixth exemplary embodiment, the return line 74 of the second heat exchanger 34 is routed to the suction line 92b of the second compressor stage 102b in the same way as in the third exemplary embodiment. In a seventh exemplary embodiment of a temperature control system according to the invention, shown in FIG. 8, those elements which are identical to the preceding exemplary embodiments are provided with the same reference symbols, so that reference can be made to the explanations relating to these exemplary embodiments with regard to the description of the same.

In contrast to the sixth exemplary embodiment, the connecting lines 136a and 136b with the corresponding control valves 138a and 138b for supplying gaseous refrigerant to the respective suction lines 92a and 92b of the compressor stages 102a and 102b are missing in the seventh exemplary embodiment.

Instead of these, connecting lines 176a and 176b with the corresponding control valves 178a and 178b are provided, similar to the sixth exemplary embodiment, which enable refrigerant, which is supplied from the bath 166 of the medium-pressure separator 164 to the feed lines 54 or 64 of the first heat exchanger 32 or of the second heat exchanger 34, respectively , branched off and fed to the suction lines 92a and 92b for cooling the sucked gaseous refrigerant.

Furthermore, in the same way as in the sixth exemplary embodiment, the return line 74 of the second heat exchanger 34 is connected to the suction line 92b.

In an eighth exemplary embodiment of a temperature control system according to the invention, shown in FIG. 9, the connecting line 132a that is still present in the sixth and seventh exemplary embodiment according to FIGS Control valve 154 provided to simplify the system. Otherwise, the connecting lines 136a and 136b with the control valves 138a and 138b are still present, as are the connecting lines 172a and 172b with the control valves 174a and 174b, so that no further explanations are required for these.

As an alternative to the sixth, seventh and eighth exemplary embodiment, there is the possibility, as in a ninth exemplary embodiment of a temperature control system according to the invention, shown in FIG 72b to connect the second compressor stage 102b, but with the suction line 92a of the first compressor stage 102a.

This can also be done in a similar way in a variant of the seventh and eighth exemplary embodiment.

Thus, also in the ninth exemplary embodiment, the elements that are identical to those of the preceding exemplary embodiments are provided with the same reference symbols, so that full content can be referred to the explanations regarding these elements in the preceding exemplary embodiments.

In all of the above exemplary embodiments, it was only assumed that the medium 14 in the space 12 is to be cooled by means of the heat exchangers 32 and 34 .

However, there is also the possibility of expanding the temperature control system according to the invention into a temperature testing or temperature simulation system, in which a heater 180 is also provided in the space 12, which allows the object 18 arranged in the space 12, for example by means of the medium 14, not only to cool, but also to heat up and thus subject to temperature cycles. In particular, it is of great advantage in this case if the refrigerant circuit 30 can be operated optimally through the various connecting lines 132, 136, 172, 176, 152 in order to generate the required cooling capacity on the one hand and the individual compressor stage 102 or the two compressor stages 102a on the other and 102b to operate at optimum efficiency and operating conditions.

In all of the exemplary embodiments described above, the controller 86 expediently controls not only the control valves 82 and 84 but at least one of the other control valves 134, 138, 144, 146, 154, 174, 178, according to the required cooling capacity or temperature in the room 12 and for the Compressor stages 102, 102a, 102b suitable operating conditions by detecting the occurring pressures and temperatures.

Claims

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

1. Temperature control system (10), comprising a medium (14) to be temperature-controlled, with which at least one heat exchanger (32, 34) for absorbing heat from the medium (14) interacts, and a refrigerant circuit (30) which the at least one Heat exchanger (32, 34) supplies refrigerant for expansion, and for this purpose at least one compressor stage (102) compressing expanded refrigerant in the heat exchanger (32, 34) and a heat exchanger (122, 126) dissipating heat from the compressed refrigerant and a control valve (82, 84) for controlling the mass flow of the compressed refrigerant to the at least one heat exchanger (32, 34) for absorbing heat, d a r c h e k e n n z e i c h n e t that a first heat exchanger (32) is designed such that the first heat exchanger (32) is connected to a supply line (33 ) the refrigerant then enters a refrigerant distributor (36) and proceeds from there through at least one mass flow-limiting D üsenelement (42) in at least one heat exchanger channel (44) occurs and expands in this.

2. Temperature control system according to Claim 1, characterized in that the refrigerant in the heat exchanger channel (44) adjoining the nozzle element (42) expands to a pressure which is below the triple point of the refrigerant.

3. Temperature control system (10) according to the preamble of claim 1 or according to one of the preceding claims, characterized in that a first (32) and a second heat exchanger (34) interact with the medium (14), that the first heat exchanger (32) for cooling the medium (14) to temperatures of less than approximately 223 K, that the second heat exchanger (34) is designed to cool the medium to temperatures above approximately 223 K and that the refrigerant circuit (30) is designed in such a way that, during operation, it either feeds refrigerant into the first heat exchanger (32) or feeds into the second heat exchanger (34). . Temperature control system according to Claim 3, characterized in that the refrigerant circuit (30) has a feed line (33) to the first heat exchanger (32) and a feed line (35) to the second heat exchanger (34), and that in each of the feed lines (33, 35) a control valve (82, 84) controlled by a controller (86) of the refrigerant circuit (30) is provided for controlling the mass flow fed to the respective heat exchanger (32, 34).

5. Temperature control system according to claim 3 or 4, characterized in that a control (86) depending on the required temperature of the medium (14) to be cooled provided in the space (12) either the second heat exchanger (34) or the first heat exchanger (32) compressed refrigerant from the refrigerant circuit (30) supplies temperature-controlled.

6. Temperature control system according to one of the preceding claims, characterized in that an expansion element (84) is arranged in the supply line (35) to the second heat exchanger (34).

7. Temperature control system according to one of the preceding claims, characterized in that in the second heat exchanger (34) there is an expansion of the refrigerant at a pressure above the sublimation range of the refrigerant. 8. Temperature control system according to one of the preceding claims, characterized in that in the second heat exchanger (34) channels in which the supplied refrigerant evaporates, extend from a supply line (35) to a return line (74) of the second heat exchanger (34). .

9. Temperature control system according to the preamble of claim 1 or according to one of the preceding claims, characterized in that a first compressor stage (102a) and at least one second compressor stage (102b) working in series with this are provided in the refrigerant circuit (30) and that the first compressor stage (102a) compresses the refrigerant from a suction pressure to an intermediate pressure and that the second compressor stage (102b) compresses the refrigerant from the intermediate pressure to high pressure.

10. Temperature control system according to claim 9, characterized in that the first compressor stage (102a) feeds the refrigerant to a heat exchanger (142) to heat the refrigerant before it enters the second compressor stage (102b).

11. Temperature control system according to one of the preceding claims, characterized in that a connecting line (152) with a control valve (154) is provided in the refrigerant circuit (30), with which gaseous refrigerant compressed to intermediate pressure from the first compressor stage (102a) is fed to a suction line of the first refrigerant compressor stage (102a) can be supplied.

12. Temperature control system according to one of the preceding claims, characterized in that the refrigerant compressed to high pressure first undergoes heat dissipation in a heat exchanger (122) and subsequently undergoes liquefaction in a heat exchanger (126). 13. Temperature control system according to claim 12, characterized in that the refrigerant circuit (30) feeds the liquefied refrigerant either to the first heat exchanger (32) or to the second heat exchanger (34) for absorbing heat.

14. Temperature control system according to the preamble of claim 1 or according to one of the preceding claims, characterized in that the refrigerant after the high-pressure side, the refrigerant liquefying heat exchanger (126) undergoes an expansion by an expansion element (162) to a medium pressure and in a medium-pressure separator ( 164) occurs, in which a separation of gaseous (168) and liquid phase (166) takes place, and that the liquid phase (166) is supplied to the first or second heat exchanger (32, 34) absorbing heat from the medium (14). he follows.

15. Temperature control system according to Claim 14, characterized in that at least one compressor stage (102, 102a, 102b) is assigned a connecting line (172) with a control valve (174), with which the gaseous phase (168) collecting in the medium-pressure separator (164) to a suction line (92, 92a, 92) which can be fed to at least one compressor stage (102, 102a, 102b).

16. Temperature control system according to one of the preceding claims, characterized in that at least one compressor stage (102a, 102a, 102b) is assigned a connecting line (132) with a control valve (134), with which gaseous refrigerant compressed to high pressure is fed to a suction line (92, 92a , 92b) can be fed to the at least one compressor stage (102, 102a, 102b). 17. Temperature control system according to one of the preceding claims, characterized in that at least one compressor stage (102, 102a, 102b) in the refrigerant circuit (30) is assigned a connecting line (136) with a control valve (138), with which liquid refrigerant compressed to high pressure a suction line (92, 92a, 92b) which can be fed to the at least one compressor stage (102).

18. Temperature control system according to one of the preceding claims, characterized in that at least one compressor stage (102, 102a, 102b) is assigned a connecting line (176) with a control valve (178), with which compressed liquid refrigerant at medium pressure is fed to a suction line (92, 92a , 92b) can be fed to the at least one compressor stage (102, 102a, 102b).

19. Temperature control system according to one of the preceding claims, characterized in that the second heat exchanger (34) is connected on the output side to a suction line (92a, 92b) of the first compressor stage (102a) or the second compressor stage (102b).

20. Temperature control system according to the preamble of claim 1 or according to one of the preceding claims, characterized in that in the refrigerant circuit (30) a container (142) for receiving gaseous refrigerant under high pressure is provided, in which this can be temporarily stored in order to temporarily remove refrigerant from the refrigerant circuit (30).

21. Temperature control system according to claim 20, characterized in that the intermediately stored refrigerant can be fed to a suction line (92) of a compressor stage (102). 22. Temperature control system according to one of the preceding claims, characterized in that in the refrigerant circuit (30) on the respective compressor stage (102) following a lubricant separator (114) is provided for separating lubricant.

23. Temperature control system according to claim 22, characterized in that the lubricant separator (114) has a return (116) for the separated lubricant to the respective compressor stage (102).

24. Temperature test system or temperature simulation system, characterized in that it has a temperature control system (10) according to one of the preceding claims and that it also has a heater (180) for heating the medium (14).

25. Method for operating a temperature control system (10), comprising a medium (14) to be temperature-controlled, with which at least one heat exchanger (32, 34) for absorbing heat from the medium (14) interacts, and a refrigerant circuit (30), which supplies the at least one heat exchanger (32, 34) with refrigerant for expansion and for this purpose at least one compressor stage (102) compressing expanded refrigerant in the heat exchanger (32, 34) and a heat exchanger (122, 126) dissipating heat from the compressed refrigerant and a control valve (82, 84) for controlling the mass flow of the compressed refrigerant to the at least one heat exchanger (32, 34) for absorbing heat, characterized in that in the first heat exchanger (32), following a supply line (33), the refrigerant is fed to a refrigerant distributor (36) and, starting from there, is fed through at least one nozzle element (42) that limits the mass flow to at least one heat exchanger channel (44) and expands in it .

26. The method according to claim 25, characterized in that the refrigerant distributor (36) is supplied with the refrigerant at a pressure above a triple point of the refrigerant.

27. The method according to claim 26, characterized in that the coolant is supplied to the coolant distributor (36) in a supercritical state of the same.

28. The method according to claim 26, characterized in that the refrigerant is supplied to the refrigerant distributor (36) with a liquid phase and a gaseous phase.

29. The method according to claim 26, characterized in that the refrigerant is supplied to the refrigerant distributor (36) in the liquid phase.

30. The method according to any one of claims 25 to 29, characterized in that the nozzle element (42) 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. 31. The method according to any one of claims 25 to 30, characterized in that the refrigerant in the nozzle element (42) adjoining the heat exchanger channel (44) is expanded by sublimation.

32. The method according to claim 31, characterized in that a pressure of the refrigerant which is below the triple point of the refrigerant is maintained in the at least one heat exchanger channel (44).

33. The method according to claim 31 or 32, characterized in that the refrigerant in the at least one heat exchanger channel (44) is kept at a pressure corresponding to a sublimation pressure of the refrigerant.

34. The method according to the preamble of claim 25 or according to one of claims 25 to 33, characterized in that a first (32) and a second heat exchanger (34) interact with the medium (14), that the first heat exchanger (32) for Cooling of the medium (14) to temperatures of less than approximately 223 K is used, that the second heat exchanger (34) is used to cool the medium to temperatures above approximately 223 K and that the refrigerant circuit (30) is operated in such a way that it either Feeds refrigerant into the first heat exchanger (32) or into the second heat exchanger (34).

35. The method according to claim 34, characterized in that the refrigerant circuit (30) has a feed line (33) to the first heat exchanger (32) and a feed line (35) to the second heat exchanger (34) and that in each of the feed lines (33 , 35) by a controller (86) of the refrigerant circuit (30) of the respective heat exchanger (32, 34) fed mass flow is controlled.

36. The method according to claim 34 or 35, characterized in that depending on the required temperature of the medium (14) to be cooled provided in the space (12) either the second heat exchanger (34) or the first heat exchanger (32) compressed refrigerant from the refrigerant circuit (30) is supplied under temperature control.

37. The method according to any one of claims 34 to 36, characterized in that in the feed line (35) to the second heat exchanger (34) there is an expansion of the refrigerant.

38. The method as claimed in one of claims 34 to 37, characterized in that the second heat exchanger (34) is operated in such a way that the refrigerant expands in it at a pressure above the sublimation range of the refrigerant.

39. The method according to any one of claims 34 to 38, characterized in that the second heat exchanger (34) is designed as a conventional heat exchanger (34), in particular as an evaporator. 0. The method according to the preamble of claim 25 or according to one of claims 25 to 39, characterized in that a first compressor stage (102a) and at least one second compressor stage (102b) working in series with this are provided in the refrigerant circuit (30), that with the first compressor stage (102a) the refrigerant is compressed from a suction pressure to an intermediate pressure and that with the second compressor stage (102b) the refrigerant is compressed from the intermediate pressure to high pressure. 1. The method according to claim 40, characterized in that from the first compressor stage (102a) the refrigerant is fed to a heat exchanger (142) for desuperheating of the refrigerant before it enters the second compressor stage (102b). 2. The method according to any one of claims 25 to 41, characterized in that in the refrigerant circuit (30) of the first compressor stage (102a) compressed to intermediate pressure gaseous refrigerant is supplied to this demand-controlled on the suction side. 3. The method according to any one of claims 25 to 42, characterized in that the refrigerant compressed to high pressure is first deheated in a heat exchanger (122) and is subsequently liquefied in a heat exchanger (126). 4. The method according to claim 43, characterized in that the refrigerant circuit (30) the liquefied refrigerant after liquefaction either the first heat exchanger (32) or the second heat exchanger (34) for absorbing heat from the medium (14) is supplied temperature-controlled. - 50 -

WO 2022/101139 PCT/EP2021/080951 5. The method according to the preamble of claim 25 or according to any one of claims 25 to 44, characterized in that the refrigerant is expanded to a medium pressure after the high-pressure side, liquefaction and in a medium-pressure separator (164) is collected, in which a separation of gaseous (168) and liquid phase (166) takes place, and that the liquid phase is supplied to the first or second heat exchanger (32, 34) absorbing heat from the medium (14) under temperature control. 6. The method as claimed in claim 45, characterized in that a gaseous phase (168) collecting in the medium-pressure separator is fed to at least one compressor stage (102, 102a, 102b) on the suction side under medium-pressure control. 7. The method according to any one of claims 25 to 46, characterized in that at least one compressor stage (102a, 102a, 102b) compressed to high pressure gaseous refrigerant is supplied demand-controlled on the suction side. 8. The method according to any one of claims 25 to 47, characterized in that at least one compressor stage (102, 102a, 102b) compressed to high pressure liquid refrigerant is supplied demand-controlled on the suction side. 9. The method according to any one of claims 25 to 48, characterized in that at least one compressor stage (102, 102a, 102b) compressed liquid refrigerant is supplied at medium pressure demand-controlled on the suction side. - 51 -

WO 2022/101139 PCT/EP2021/080951

50. The method according to any one of claims 25 to 49, characterized in that expanded refrigerant from the second heat exchanger (34) of the first compressor stage (102a) or the second compressor stage (102b) is supplied on the suction side.

51. The method according to the preamble of claim 25 or according to any one of claims 25 to 50, characterized in that in the refrigerant circuit (30) under high pressure gaseous refrigerant is temporarily stored in a container (142) as required.

52. The method according to claim 51, characterized in that the intermediately stored refrigerant is supplied to a compressor stage (102) on the suction side in a demand-controlled manner.

53. The method according to any one of claims 25 to 52, characterized in that in the refrigerant circuit (30) following the respective compressor stage (102) a separation of lubricant takes place.

54. The method according to claim 53, characterized in that the separated lubricant is supplied to the respective compressor stage (102).

55. Method for operating a temperature testing system or a temperature simulation system, characterized in that this is carried out according to a method according to one of claims 25 to 54 and the medium (14) is additionally heated by a heater (180) in a demand-controlled manner.