EP4311989A1 - Refrigerant circuit - Google Patents

Abstract

In order to improve the heat transfer from the heat exchanger body to the sublimating refrigerant flowing into the heat exchanger channel, it is proposed that a mixture of refrigerant and a functional conveying agent flows through the heat exchanger channel, so that the functional conveying agent is still present as a liquid functional conveying agent during the sublimation of the refrigerant, which is in the heat exchanger channel improves heat transfer between the sublimating refrigerant and the heat exchanger body having the heat exchanger channel.

Description

The invention relates to a refrigerant circuit, comprising a refrigerant compressor, which compresses refrigerant to a high pressure level that is above the triple point of the refrigerant, and from which the compressed refrigerant is fed to a heat exchanger unit, which extracts heat from the refrigerant, an expansion element arranged downstream of the heat exchanger unit , which is followed by at least one heat exchanger channel, wherein the expansion element expands the compressed refrigerant in such a way that the triple point in the expansion element itself is not exceeded and that the refrigerant, after leaving the expansion element, falls below the triple point in the subsequent heat exchanger channel and sublimes, thereby generating heat from a receives a heat source surrounding the heat exchanger body having the heat exchanger channel, as well as a collecting line which receives the refrigerant after leaving the heat exchanger channel and supplies it to the refrigerant compressor.

Such refrigerant circuits are known from the prior art.

The problem with these is that heat transfer from the heat exchanger body to the refrigerant, in particular CO2, flowing and sublimating in the heat exchanger channel limits the heat absorption of the heat exchanger body.

The invention is therefore based on the object of improving the heat transfer from the heat exchanger body to the sublimating refrigerant flowing into the heat exchanger channel.

This object is achieved according to the invention in a refrigerant circuit of the type described above in that a mixture of refrigerant and a functional conveying medium flows through the heat exchanger channel During the sublimation of the refrigerant, the functional conveying agent is still present as a liquid functional conveying agent, which improves heat transfer in the heat exchanger channel between the sublimating refrigerant and the heat exchanger body having the heat transfer channel.

The advantage of the solution according to the invention can therefore be seen in the fact that the functional conveying agent, which is still liquid during the sublimation of the refrigerant, opens up the possibility of improving the heat transfer between them by wetting, on the one hand, the sublimating refrigerant and, on the other hand, walls of the heat exchanger body surrounding the heat exchanger channel, and thus in particular the To increase heat absorption by the sublimating refrigerant per unit of time.

In order to create defined conditions in the refrigerant circuit, it is preferably provided that a lubricant separator is arranged between the refrigerant compressor and the high-pressure side heat exchanger unit, which ensures that the lubricant from the refrigerant compressor does not circulate in undefined quantities in the refrigerant circuit, but after the refrigerant compressor in the refrigerant circuit is largely withdrawn again.

This can prevent undefined large amounts of lubricant from circulating in the refrigerant circuit and causing blockages in the heat exchanger channel.

It is particularly advantageous if the lubricant separator is a coalescence separator, since with such a coalescence separator a very high separation rate of lubricant can be achieved in order to largely remove it from the refrigerant, which subsequently enters the heat exchanger channel, and thus problems due to blockages in the heat exchanger channel avoid.

On the other hand, the functional conveying agent should not change and/or impair the operating conditions of the refrigerant circuit with the refrigerant intended for sublimation without the addition of the functional conveying agent.

For this reason, it is preferably provided that the functional conveying agent is selected such that the mixture of the refrigerant, in particular CO2, and the functional conveying agent is non-flammable, preferably also non-toxic, so that the addition of the functional conveying agent does not create any additional risk potential due to the refrigerant circuit arises.

The "non-flammable" requirement requires that the mixture be classified as "1" or "A1" according to the ANSI/ASHRAE Standard 34 based on ASTM E681, where "1" is non-flammable and "A1" is non-toxic and not means flammable.

A further advantageous specification provides that the functional conveying agent is selected such that the mixture of the refrigerant and the functional conveying agent has a triple point that is lowered by a maximum of 5 K, preferably a maximum of 3 K, compared to the triple point of the pure refrigerant.

This specification for the functional conveying means allows the operating conditions for the refrigerant circuit to be maintained unchanged, so that no additional measures are required to maintain the functions and/or operating conditions of the refrigerant circuit.

Furthermore, it is preferably provided that the functional conveying agent is selected such that the mixture of the refrigerant and the functional conveying agent has a temperature glide, that is to say a difference between the dew temperature and the boiling temperature, of a maximum of 5 K in the area between the triple point and the critical point , preferably a maximum of 3 K.

This measure ensures that no additional measures are required for optimal heat transfer when operating the refrigerant circuit, since the difference between the dew temperature and the boiling temperature of the mixture of refrigerant and functional fluid has no significant impact on the operating conditions.

A further advantageous condition provides that the functional conveying agent is selected such that the mixture of the refrigerant and the functional conveying agent has a global warming potential, hereinafter referred to as “global warming potential,” of less than 150.

This measure can ensure that the mixture of refrigerant and functional conveying agent has a minimal impact on the environmental compatibility of operating such a refrigerant circuit.

It is preferably provided that the proportion of the functional conveying agent in the mixture of refrigerant and functional conveying agent is selected such that no blockage occurs in the heat exchanger channel during the sublimation of the refrigerant.

This measure excludes functional conveying agents that separate out of the mixture in the heat exchanger channel and settle or become viscous in such a way that the flow conditions in the heat exchanger channel are significantly impaired.

For example, it is provided that the functional conveying agent in the refrigerant circuit has a circulating lubricant with a defined mass proportion of the total mass of the mixture of refrigerant and functional conveying agent.

It is particularly advantageous if the refrigerant circuit is supplied with metered lubricant from the lubricant separator as a functional conveying medium by means of a supply line and a metering unit assigned to it.

This makes it possible to achieve a defined circulation rate of lubricant in the area of the refrigerant circuit that takes place on the lubricant separator.

As an alternative or in addition to the direct supply of lubricant from the lubricant separator as a functional conveying agent, a further advantageous solution provides that a mixture of refrigerant and lubricant is fed to the refrigerant circuit as a functional conveying agent in a metered manner by means of a feed line branching off between the refrigerant compressor and the lubricant separator and a metering unit assigned to this.

This solution has the advantage that the lubricant is present in a reduced proportion in the refrigerant and the exact lubricant dosage can therefore be achieved even more easily by metering this combination of refrigerant and lubricant.

Since the lubricant is present in the high-pressure and hot refrigerant, a condenser or gas cooler is preferably provided in the supply line, which makes it possible to cool the mixture of refrigerant and lubricant before it is fed back into the refrigerant circuit.

A wide variety of options for supplying the lubricant as a functional conveyor are conceivable.

One possibility provides that the refrigerant circuit in the area of the high-pressure side heat exchanger unit is supplied with metered lubricant as a functional conveyor so that the lubricant can mix well with the refrigerant before it enters the heat exchanger channel.

Another supplementary or alternative advantageous possibility of supplying lubricant as a functional conveying agent provides that lubricant is supplied in a metered manner as a functional conveying agent to the refrigerant circuit in the area of the expansion element.

The lubricant could be supplied to the refrigerant as a functional conveying agent upstream of the expansion element.

A particularly advantageous solution provides that lubricant is supplied in metered quantities as a functional conveying agent to the refrigerant circuit following the expansion element, in particular immediately following the expansion element.

This can be done, for example, in an area of the heat exchanger channel, which is arranged close to the respective expansion element, preferably in direct connection to this expansion element, so that the lubricant mixes with the solid phase of the refrigerant that is forming or the already sublimating refrigerant and then becomes effective can be.

In particular, the lubricant present in the mixture can be a lubricant for the refrigerant compressor, which, however, must be selected so that it does not settle in a viscous form in the heat exchanger channel and clog it.

With regard to the amount of lubricant added, it is preferably provided that the mass fraction of the lubricant present in the mixture in the heat exchanger channel is based on the mixture of refrigerant and functional promoting means is more than 0.02% by mass, preferably more than 0.04% by mass.

Furthermore, it is preferably provided that in the heat exchanger channel the mass fraction of the lubricant present in the mixture, based on the mixture of refrigerant and functional conveying agent, is a maximum of 1 mass%, better a maximum of 0.11 mass%, even better a maximum of 0.05 mass%.

With such mass proportions of the lubricant it is ensured that on the one hand it acts as a functional conveying medium, but on the other hand it cannot settle in the heat exchanger channel and cause a blockage.

Alternatively or in addition to the use of lubricant as a functional conveying agent, an advantageous solution for a functional conveying agent according to the invention provides that the functional conveying agent comprises at least one additional refrigerant.

Such an additional refrigerant is a refrigerant which differs from the refrigerant, for example CO2, which is intended for the basic function of the refrigerant circuit and in particular sublimates in the heat exchanger channel.

In the case of such an additional refrigerant, it is particularly required that the proportion of the additional refrigerant representing the functional conveying agent in the mixture of refrigerant and functional conveying agent is selected such that the mixture of refrigerant and functional conveying agent has a temperature glide that is smaller both in the area between the triple point and the critical point than 5 K, and, based on the pure refrigerant, has a triple point depression that is less than 5 K, and in particular is not combustible and in particular also has a “global warming potential” of less than 150.

A further advantageous selection of such functional funding means that the functional funding means contains one or more of the additional refrigerants (E)-1,3,3,3-tetrafluoropropene, 1,1,1,2-tetrafluoroethane, 1,1-difluoroethene, 2,3 ,3,3-Tetrafluoropropene, difluoromethane, ethane, ethene, ethyne, fluoroethene, fluoromethane, pentafluoroethane, propane, propene, xenon.

This means that the functional conveying agent can not only be formed from an additional refrigerant, but can also be a mixture of several such additional refrigerants, with the overall mixture of additional refrigerants formed as a functional conveying agent fulfilling in particular one or more or preferably all of the above-mentioned conditions.

It is particularly advantageous if the refrigerant in the refrigerant circuit according to the invention is COz.

When COz is used as a refrigerant, it is preferably provided that it has a mass proportion in the range of 80% by mass to 99% by mass based on the total mass of the mixture of the refrigerant COz and the functional conveying agent.

Furthermore, it is preferably provided that the refrigerant COz has a molar proportion in the range from 88 mol% to 99.6 mol% based on 100 mol% of the mixture of the refrigerant COz and the functional conveying agent.

1. 1. Kältemittelkreislauf (10), umfassend einen Kältemittelverdichter (12), welcher Kältemittel auf ein Hochdruckniveau verdichtet, das über dem Tripelpunkt des Kältemittels liegt, und von welchem ausgehend das verdichtete Kältemittel einer Wärmeübertragereinheit (18) zugeführt wird, welche dem Kältemittel Wärme entzieht, ein auf die Wärmeübertragereinheit (18) nachfolgend angeordnetes Expansionsorgan (34), an welches sich mindestens ein Wärmeübertragerkanal (36) anschließt, wobei das Expansionsorgan (34) das verdichtete Kältemittel derart expandiert, dass der Tripelpunkt in dem Expansionsorgan (34) selbst nicht unterschritten wird und dass das Kältemittel nach Verlassen des Expansionsorgans (34) in dem nachfolgenden Wärmeübertragerkanal (36) den Tripelpunkt unterschreitet und sublimiert und dabei Wärme von einer einen den Wärmeübertragerkanal (36) aufweisenden Wärmeübertragerkörper (40) umgebenden Wärmequelle (28) aufnimmt, sowie eine das Kältemittel nach Verlassen des Wärmeübertragerkanals (36) aufnehmende und dem Kältemittelverdichter (12) zuführende Sammelleitung (38), wobei den Wärmeübertragerkanal (36) ein Gemisch aus Kältemittel und einem Funktionsfördermittel (FFM) durchströmt, dass das Funktionsfördermittel (FFM) bei der Sublimation des Kältemittels noch als flüssiges Funktionsfördermittel (FFM) vorliegt, welches in dem Wärmeübertragerkanal (36) einen Wärmeübergang zwischen dem sublimierenden Kältemittel und dem den Wärmeübertragerkanal (36) aufweisenden Wärmeübertragerkörper (40) verbessert.
2. 2. Kältemittelkreislauf nach Ausführungsform 1, wobei zwischen dem Kältemittelverdichter (12) und der hochdruckseitigen Wärmeübertragereinheit (18) ein Schmiermittelabscheider (50) angeordnet ist.
3. 3. Kältemittelkreislauf nach Ausführungsform 2, wobei der Schmiermittelabscheider (50) ein Koaleszenzabscheider ist.
4. 4. Kältemittelkreislauf nach einer der voranstehenden Ausführungsformen, das Funktionsfördermittel (FFM) so gewählt ist, dass das Gemisch aus dem Kältemittel und dem Funktionsfördermittel (FFM) nicht brennbar ist.
5. 5. Kältemittelkreislauf nach einer der voranstehenden Ausführungsformen, wobei das Funktionsfördermittel (FFM) derart ausgewählt ist, dass das Gemisch aus dem Kältemittel und dem Funktionsfördermittel (FFM) einen Tripelpunkt aufweist, der gegenüber dem Tripelpunkt des reinen Kältemittels um maximal 5 K, vorzugsweise maximal 3 K, abgesenkt ist.
6. 6. Kältemittelkreislauf nach einer der voranstehenden Ausführungsformen, wobei das Funktionsfördermittel (FFM) derart ausgewählt ist, dass das Gemisch aus dem Kältemittel und dem Funktionsfördermittel (FFM) im Bereich zwischen dem Tripelpunkt und dem kritischen Punkt einen Temperaturgleit (TG), das heißt eine Differenz zwischen der Tautemperatur (T") und der Siedetemperatur (T), aufweist, der maximal 5 K, vorzugsweise maximal 3 K, beträgt.
7. 7. Kältemittelkreislauf nach einer der voranstehenden Ausführungsformen, wobei das Funktionsfördermittel (FFM) derart ausgewählt ist, dass das Gemisch aus dem Kältemittel und dem Funktionsfördermittel (FFM) ein "global warming potential" (GWP) von weniger als 150 aufweist.
8. 8. Kältemittelkreislauf nach einer der voranstehenden Ausführungsformen, wobei der Anteil des Funktionsfördermittels (FFM) in dem Gemisch aus Kältemittel und Funktionsfördermittel (FFM) derart gewählt ist, dass bei der Sublimation des Kältemittels keine Verstopfung im Wärmeübertragerkanal (36) auftritt.
9. 9. Kältemittelkreislauf nach einer der voranstehenden Ausführungsformen, wobei das Funktionsfördermittel (FFM) im Kältemittelkreislauf (10) ein, insbesondere mit einem definierten Masseanteil an der Gesamtmasse des Gemischs aus Kältemittel und Funktionsfördermittel (FFM), zumindest den Wärmeübertragerkanal durchströmendes Schmiermittel umfasst.
10. 10. Kältemittelkreislauf nach Ausführungsform 9, wobei dem Kältemittelkreislauf (10) mittels einer Zufuhrleitung (62, 72, 82, 92, 102) und einer dieser zugeordneten Dosiereinheit (64, 74, 84, 94, 104) dosiert Schmiermittel aus dem Schmiermittelabscheider (50) als Funktionsfördermittel (FFM) zugeführt wird.
11. 11. Kältemittelkreislauf nach einer der Ausführungsformen 9 oder 10, wobei dem Kältemittelkreislauf (10) mittels einer zwischen dem Kältemittelverdichter (12) und dem Schmiermittelabscheider (50) abzweigenden Zufuhrleitung (112, 122, 132, 142, 152) und einer dieser zugeordneten Dosiereinheit (114, 124, 134, 144, 154) dosiert eine Mischung aus Kältemittel und Schmiermittel als Funktionsfördermittel zugeführt wird.
12. 12. Kältemittelkreislauf nach einer der Ausführungsformen 9 bis 11, wobei dem Kältemittelkreislauf (10) im Bereich der hochdruckseitigen Wärmeüberträgereinheit (18) dosiert Schmiermittel als Funktionsfördermittel (FFM) zugeführt wird.
13. 13. Kältemittelkreislauf nach einer der Ausführungsformen 9 bis 12, wobei dem Kältemittelkreislauf (10) im Bereich des Expansionsorgans (34) Schmiermittel als Funktionsfördermittel (FFM) dosiert zugeführt wird.
14. 14. Kältemittelkreislauf nach einer der Ausführungsformen 9 bis 13, wobei dem Kältemittelkreislauf (10) im Ausschluss an das Expansionsorgan (34) Schmiermittel als Funktionsfördermittel (FFM) dosiert zugeführt wird.
15. 15. Kältemittelkreislauf nach einer der Ausführungsformen 9 bis 14, wobei im Wärmeübertragerkanal (36) der Masseanteil des in dem Gemisch vorhandenen Schmiermittels bezogen auf die Gesamtmasse des Gemischs aus Kältemittel und Funktionsfördermittel (FFM) mehr als 0,02 Masse %, vorzugsweise mehr als 0,04 Masse %, beträgt.
16. 16. Kältemittelkreislauf nach Ausführungsform 15, wobei im Wärmeübertragerkanal (36) der Masseanteil des in dem Gemisch vorhandenen Schmiermittel bezogen auf die Gesamtmasse des Gemischs aus Kältemittel und Funktionsfördermittel (FFM) maximal 1 Masse %, besser maximal 0,11 Masse %, noch besser maximal 0,05 Masse %, beträgt.
17. 17. Kältemittelkreislauf nach einer der voranstehenden Ausführungsformen, wobei das Funktionsfördermittel (FFM) mindestens ein Zusatzkältemittel umfasst.
18. 18. Kältemittelkreislauf nach Ausführungsform 17, wobei der Anteil des das Funktionsfördermittel (FFM) darstellenden Zusatzkältemittels in dem Gemisch aus Kältemittel und Funktionsfördermittel (FFM) derart ausgewählt ist, dass das Gemisch aus Kältemittel und Funktionsfördermittel (FFM) im Bereich zwischen dem Tripelpunkt und dem kritischen Punkt einen Temperaturgleit (TG) aufweist, der kleiner als 5 K ist, und bezogen auf das reine Kältemittel eine Tripelpunktabsenkung aufweist, die kleiner als 5 K ist, und insbesondere nicht brennbar ist und insbesondere außerdem ein "global warming potential" (GWP) kleiner 150 aufweist.
19. 19. Kältemittelkreislauf nach einer der Ausführungsformen 17 oder 18, wobei das Funktionsfördermittel (FFM) eines oder mehrere der Zusatzkältemittel (E)-1,3,3,3-Tetrafluorpropen, 1,1,1,2-Tetrafluorethan, 1,1-Diflourethen, 2,3,3,3-Tetrafluorpropen, Difluormethan, Ethan, Ethen, Ethin, Fluorethen, Fluormethan, Pentafluorethan, Propan, Propen, Xenon umfasst.
20. 20. Kältemittelkreislauf nach einer der voranstehenden Ausführungsformen, wobei das Kältemittel COz ist.
21. 21. Kältemittelkreislauf nach Ausführungsform 20, wobei das Kältemittel COz einen Masseanteil im Bereich von 80 Masse % bis 99 Masse % bezogen auf die Gesamtmasse des Gemischs aus dem Kältemittel COz und dem Funktionsfördermittel (FFM) aufweist.
22. 22. Kältemittelkreislauf nach einer der Ausführungsformen 20 oder 21, wobei das Kältemittel COz einen Molanteil im Bereich von 88 Mol % bis 99,6 Mol % bezogen auf 100 Mol % des Gemischs aus dem Kältemittel COz und dem Funktionsfördermittel (FFM) aufweist.

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

1. 1. Refrigerant circuit (10), comprising a refrigerant compressor (12), which compresses refrigerant to a high pressure level that is above the triple point of the refrigerant, and from which the compressed refrigerant is fed to a heat exchanger unit (18), which is the Heat is removed from the refrigerant, an expansion element (34) arranged downstream of the heat exchanger unit (18), to which at least one heat exchanger channel (36) is connected, the expansion element (34) expanding the compressed refrigerant in such a way that the triple point in the expansion element (34) itself is not fallen below and that the refrigerant, after leaving the expansion element (34), falls below the triple point in the subsequent heat exchanger channel (36) and sublimes and thereby absorbs heat from a heat source (28) surrounding a heat exchanger body (40) having the heat exchanger channel (36), and a collecting line (38) which receives the refrigerant after leaving the heat exchanger channel (36) and supplies it to the refrigerant compressor (12), with a mixture of refrigerant and a functional conveying medium (FFM) flowing through the heat exchanger channel (36) so that the functional conveying medium (FFM) flows through the Sublimation of the refrigerant is still present as a liquid functional conveying medium (FFM), which improves heat transfer in the heat exchanger channel (36) between the sublimating refrigerant and the heat exchanger body (40) having the heat exchanger channel (36).
2. 2. Refrigerant circuit according to embodiment 1, wherein a lubricant separator (50) is arranged between the refrigerant compressor (12) and the high-pressure side heat exchanger unit (18).
3. 3. Refrigerant circuit according to embodiment 2, wherein the lubricant separator (50) is a coalescence separator.
4. 4. Refrigerant circuit according to one of the preceding embodiments, the functional conveying medium (FFM) is selected so that the mixture of the refrigerant and the functional conveying medium (FFM) is non-flammable.
5. 5. Refrigerant circuit according to one of the preceding embodiments, wherein the functional conveying agent (FFM) is selected such that the mixture of the refrigerant and the functional conveying agent (FFM). Has triple point, which is lowered by a maximum of 5 K, preferably a maximum of 3 K, compared to the triple point of the pure refrigerant.
6. 6. Refrigerant circuit according to one of the preceding embodiments, wherein the functional conveying agent (FFM) is selected such that the mixture of the refrigerant and the functional conveying agent (FFM) has a temperature glide (TG), i.e. a difference, in the area between the triple point and the critical point between the dew temperature (T") and the boiling temperature (T), which is a maximum of 5 K, preferably a maximum of 3 K.
7. 7. Refrigerant circuit according to one of the preceding embodiments, wherein the functional conveying agent (FFM) is selected such that the mixture of the refrigerant and the functional conveying agent (FFM) has a “global warming potential” (GWP) of less than 150.
8. 8. Refrigerant circuit according to one of the preceding embodiments, wherein the proportion of the functional conveying agent (FFM) in the mixture of refrigerant and functional conveying agent (FFM) is selected such that no blockage occurs in the heat exchanger channel (36) during the sublimation of the refrigerant.
9. 9. Refrigerant circuit according to one of the preceding embodiments, wherein the functional conveying agent (FFM) in the refrigerant circuit (10) comprises a lubricant flowing through at least the heat exchanger channel, in particular with a defined mass proportion of the total mass of the mixture of refrigerant and functional conveying agent (FFM).
10. 10. Refrigerant circuit according to embodiment 9, wherein the refrigerant circuit (10) is metered with lubricant from the lubricant separator (50 ) is supplied as a functional support agent (FFM).
11. 11. Refrigerant circuit according to one of embodiments 9 or 10, wherein the refrigerant circuit (10) is supplied by means of a supply line (112, 122, 132, 142, 152) branching off between the refrigerant compressor (12) and the lubricant separator (50) and a metering unit assigned to this ( 114, 124, 134, 144, 154) a mixture of refrigerant and lubricant is metered in as a functional conveying medium.
12. 12. Refrigerant circuit according to one of embodiments 9 to 11, wherein the refrigerant circuit (10) in the area of the high-pressure side heat exchanger unit (18) is supplied with metered lubricant as a functional conveying medium (FFM).
13. 13. Refrigerant circuit according to one of embodiments 9 to 12, wherein the refrigerant circuit (10) in the area of the expansion element (34) is supplied with lubricant in a metered manner as a functional conveying medium (FFM).
14. 14. Refrigerant circuit according to one of embodiments 9 to 13, wherein the refrigerant circuit (10) is supplied in metered quantities as a functional conveying medium (FFM) to the exclusion of the expansion element (34).
15. 15. Refrigerant circuit according to one of embodiments 9 to 14, wherein in the heat exchanger channel (36) the mass fraction of the lubricant present in the mixture, based on the total mass of the mixture of refrigerant and functional conveying agent (FFM), is more than 0.02 mass%, preferably more than 0 .04 mass%.
16. 16. Refrigerant circuit according to embodiment 15, wherein in the heat exchanger channel (36) the mass fraction of the lubricant present in the mixture based on the total mass of the mixture of refrigerant and functional conveying agent (FFM) is a maximum of 1 mass%, better a maximum of 0.11 mass%, even better a maximum 0.05% by mass.
17. 17. Refrigerant circuit according to one of the preceding embodiments, wherein the functional conveying medium (FFM) comprises at least one additional refrigerant.
18. 18. Refrigerant circuit according to embodiment 17, wherein the proportion of the additional refrigerant representing the functional conveying agent (FFM) in the mixture of refrigerant and functional conveying agent (FFM) is selected such that the mixture of refrigerant and functional conveying agent (FFM) is in the area between the triple point and the critical Point has a temperature glide (TG) that is less than 5 K, and, based on the pure refrigerant, has a triple point depression that is less than 5 K, and in particular is not combustible and in particular also has a “global warming potential” (GWP) smaller 150.
19. 19. Refrigerant circuit according to one of embodiments 17 or 18, wherein the functional conveying agent (FFM) contains one or more of the additional refrigerants (E)-1,3,3,3-tetrafluoropropene, 1,1,1,2-tetrafluoroethane, 1,1- Difluoroethene, 2,3,3,3-tetrafluoropropene, difluoromethane, ethane, ethene, ethyne, fluoroethene, fluoromethane, pentafluoroethane, propane, propene, xenon.
20. 20. Refrigerant circuit according to one of the preceding embodiments, wherein the refrigerant is COz.
21. 21. Refrigerant circuit according to embodiment 20, wherein the refrigerant COz has a mass fraction in the range from 80 mass% to 99 mass% based on the total mass of the mixture of the refrigerant COz and the functional conveying medium (FFM).
22. 22. Refrigerant circuit according to one of embodiments 20 or 21, wherein the refrigerant COz has a molar proportion in the range from 88 mol% to 99.6 mol% based on 100 mol% of the mixture of the refrigerant COz and the functional conveying agent (FFM).

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

Fig. 1

ein erstes Ausführungsbeispiel eines erfindungsgemäßen Kältemittelkreislaufs;

Fig. 2

eine vergrößerte Darstellung eines erfindungsgemäßen Wärmeübertragers mit Kältemittelverteiler und Kältemittelsammler;

Fig. 3

ein zweites Ausführungsbeispiel eines erfindungsgemäßen Kältemittelkreislaufs für die Anwendung von Schmiermittel für den Kältemittelverdichter als Funktionsfördermittel;

Fig. 4

ein drittes Ausführungsbeispiel eines erfindungsgemäßen Kältemittelkreislaufs für die Anwendung von Schmiermittel für den Kältemittelverdichter als Funktionsfördermittel;

Fig. 5

ein viertes Ausführungsbeispiel eines erfindungsgemäßen Kältemittelkreislaufs für die Anwendung von Schmiermittel für den Kältemittelverdichter als Funktionsfördermittel;

Fig. 6

ein fünftes Ausführungsbeispiel eines erfindungsgemäßen Kältemittelkreislaufs für die Anwendung von Schmiermittel für den Kältemittelverdichter als Funktionsfördermittel;

Fig. 7

ein sechstes Ausführungsbeispiel eines erfindungsgemäßen Kältemittelkreislaufs für die Anwendung von Schmiermittel für den Kältemittelverdichter als Funktionsfördermittel;

Fig. 8

ein siebtes Ausführungsbeispiel eines erfindungsgemäßen Kältemittelkreislaufs für die Anwendung von Schmiermittel für den Kältemittelverdichter als Funktionsfördermittel;

Fig. 9

ein achtes Ausführungsbeispiel eines erfindungsgemäßen Kältemittelkreislaufs für die Anwendung von Schmiermittel für den Kältemittelverdichter als Funktionsfördermittel;

Fig. 10

ein neuntes Ausführungsbeispiel eines erfindungsgemäßen Kältemittelkreislaufs für die Anwendung von Schmiermittel für den Kältemittelverdichter als Funktionsfördermittel;

Fig. 11

ein zehntes Ausführungsbeispiel eines erfindungsgemäßen Kältemittelkreislaufs für die Anwendung von Schmiermittel für den Kältemittelverdichter als Funktionsfördermittel und

Fig. 12

ein elftes Ausführungsbeispiel eines erfindungsgemäßen Kältemittelkreislaufs für die Anwendung von Schmiermittel für den Kältemittelverdichter als Funktionsfördermittel.

Show in the drawing:

Fig. 1

a first exemplary embodiment of a refrigerant circuit according to the invention;

Fig. 2

an enlarged view of a heat exchanger according to the invention with refrigerant distributor and refrigerant collector;

Fig. 3

a second exemplary embodiment of a refrigerant circuit according to the invention for the use of lubricant for the refrigerant compressor as a functional conveying medium;

Fig. 4

a third embodiment of a refrigerant circuit according to the invention for the use of lubricant for the refrigerant compressor as a functional conveying agent;

Fig. 5

a fourth exemplary embodiment of a refrigerant circuit according to the invention for the use of lubricant for the refrigerant compressor as a functional conveying agent;

Fig. 6

a fifth exemplary embodiment of a refrigerant circuit according to the invention for the use of lubricant for the refrigerant compressor as a functional conveying agent;

Fig. 7

a sixth exemplary embodiment of a refrigerant circuit according to the invention for the use of lubricant for the refrigerant compressor as a functional conveying agent;

Fig. 8

a seventh embodiment of a refrigerant circuit according to the invention for the use of lubricant for the refrigerant compressor as a functional conveying agent;

Fig. 9

an eighth embodiment of a refrigerant circuit according to the invention for the use of lubricant for the refrigerant compressor as a functional conveying agent;

Fig. 10

a ninth exemplary embodiment of a refrigerant circuit according to the invention for the use of lubricant for the refrigerant compressor as a functional conveying agent;

Fig. 11

a tenth exemplary embodiment of a refrigerant circuit according to the invention for the use of lubricant for the refrigerant compressor as a functional conveying agent and

Fig. 12

an eleventh exemplary embodiment of a refrigerant circuit according to the invention for the use of lubricant for the refrigerant compressor as a functional conveying medium.

An in Fig. 1 Illustrated embodiment of a refrigerant circuit designated as a whole by 10 comprises a refrigerant compressor 12, which compresses refrigerant supplied to a suction side 14 and discharges it to a high-pressure side 16, the refrigerant compressed to high pressure being supplied from the refrigerant circuit 10 to a high-pressure-side heat exchanger unit 18, which is in the position is to extract heat from the refrigerant that is compressed to high pressure.

For example, the heat exchanger unit 18 comprises a desuperheater 19 and a condenser or gas cooler 20, each of which dissipates a heat flow 21 and 22, respectively.

The compressed refrigerant cooled by dissipating the heat flow 22 is fed to a control valve 24, which thus makes it possible to supply 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 Fig. 1 characterized as fluid stream 28, takes place.

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 the refrigerant is subsequently supplied via nozzle channels 34 to the heat exchanger channels 36, in which the refrigerant expands while absorbing heat from the fluid stream 28 , which runs in particular transversely or perpendicular 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 heat exchanger channels 36 and from which the refrigerant is then supplied to the suction side 14 of the refrigerant compressor 12.

As in Fig. 2 shown enlarged, in a first, simple embodiment of the heat exchanger 30 according to the invention, for example, 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, 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 that the heat exchanger bodies 40 protrude with the first end region 42 into an interior 46 of the refrigerant distributor 32 and are also provided at the first end region 42 with the nozzle channel 34, which thus on the one hand receives refrigerant from the interior 46 of the refrigerant distributor 32 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 from a heat flowing around the respective heat exchanger body.

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

For example, the nozzle channels 34 are designed with regard to their cross-sectional area in such a way that the refrigerant flows in them at the critical speed, that is, 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, the expansion leading to cooling of the refrigerant takes place in the respective heat exchanger channels 36 only after the refrigerant has exited the nozzle channels 34.

In particular when using COz as a refrigerant, optionally as a mixture with additional functional conveying agents FFM explained below, for example 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 of COz, 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 is then reduced in the nozzle channel 34, but until the transition from the nozzle channel 34 into 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 essentially sublimation occurs the nozzle channel 34 is prevented.

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

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

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 48 of the refrigerant collector and is collected by it and fed to the suction side 14 of the refrigerant compressor 12 via the refrigerant circuit 10.

In order to achieve this function, the nozzle channels 34 have, for example, a diameter of less than 0.55 mm, preferably less than 0.1 mm, and, for example, a length in the range of 0.05 mm to 5 mm

The above dimensioning of the nozzle elements 34, in particular the nozzle channels 34, as well as the above-mentioned operating conditions also apply in particular to all of the exemplary embodiments described below.

In order to achieve a defined operating state of the refrigerant, in particular the CO ₂ , the refrigerant compressor 12 on the high pressure side 16 is followed by a lubricant separator 50, which consists of the compressed refrigerant, in particular CO2, lubricant, in particular oil, with the highest possible lubricant separation efficiency, for example larger 99%, in order to achieve a defined and as low as possible lubricant circulation rate in the refrigerant circuit.

Such a lubricant separator 50 is preferably a coalescence separator with which a separation efficiency of more than 99.99% can be achieved.

In order to ensure reliable and low-wear operation of the refrigerant compressor 12, a part, in particular a predominant part, of the lubricant collecting in the lubricant separator 50 in a lubricant bath 54 from the lubricant bath 54 is supplied to the refrigerant compressor 12 via a feed line 58 provided with a metering unit 56 Suction side 14 or directly to a lubricant sump of the refrigerant compressor 12. For example, the metering unit 56 is controlled according to the lubricant level of the lubricant bath 54.

In order to improve the heat absorption of the refrigerant sublimating in the heat transfer channels 36, for example COz, from the walls of the respective heat exchanger body 40 delimiting the heat transfer channel 36 and thus also from the fluid stream 28 flowing around the heat exchanger body 40, without thereby increasing the heat absorption primarily caused by the sublimating refrigerant, in particular COz To significantly change predetermined operating conditions and properties, a functional conveying agent FFM, which increases the heat transfer between the sublimating refrigerant and the walls of the heat exchanger body 40 and is still liquid at the sublimation temperatures of the refrigerant, is preferably added to the refrigerant, in particular COz, in the heat exchanger channels 36 to form a mixture , which preferably performs an effective wetting function in the heat exchanger channels 36 between the sublimenting refrigerant, in particular refrigerant COz, and the walls of the heat exchanger body 40, in order to ensure that the solid state of the refrigerant changes more quickly into the gaseous state, so that the refrigerant in able to absorb larger amounts of heat in a shorter period of time.

Such a functional conveying agent FFM is designed in particular in such a way that the triple point of the mixture of the refrigerant and the functional conveying agent FFM is only insignificantly lowered relative to the pure refrigerant, for example by less than 5 K.

A further requirement for such a functional conveying agent FFM is that the mixture of the refrigerant and the functional conveying agent FFM should be non-flammable, whereby the mixture according to ANSI/ASHRAE Standard 34, based on ASTM E681, is used for the “non-flammable” requirement must be classifiable as “1” or “A1”.

Furthermore, the requirement for such a functional conveying agent FFM is that the mixture of the refrigerant and the functional conveying agent FFM has a temperature glide TG in the area between the triple point and the critical point, that is, a difference between the dew temperature T "and the boiling temperature T ' which is smaller than 5 K.

In addition, it is expediently also provided that the functional conveying agent FFM is selected such that the mixture of the refrigerant and the functional conveying agent FFM has a “global warming potential” GWP that is less than 150.

A further requirement for a functional conveying agent FFM according to the invention is that the mixture of the refrigerant and the functional conveying agent FFM is selected such that no blockage occurs during the sublimation of the refrigerant in the heat exchanger channel 36.

One possibility is to use a known refrigerant, referred to in this context as an additional refrigerant, as such a functional conveying agent FFM, whereby the mixture of the refrigerant and the additional refrigerant serving as a functional conveying agent FFM preferably not only has the triple point of the mixture relative to the triple point of the refrigerant by less than 5 K should be reduced, but also as low as possible “global warming potential” GWP should have, for example preferably a “global warming potential” GWP of less than 150.

Such additional refrigerants to be used as FFM functional conveying agents in the solution according to the invention are listed in Table 1.

Table 1 shows, on the one hand, the designation of additional refrigerants, the GWP and the ASHRAE designation of the same.

Furthermore, Table 1 shows how large the minimum mass proportion and proportion of the functional conveying agent FFM used should be in relation to the total mass of the mixture of refrigerant and functional conveying agent FFM, and how large the maximum mass proportion and quantitative proportion of this functional conveying agent FFM based on the total mass of the mixture of refrigerant and functional conveying agent should be, how large the GWP of the mixture of refrigerant and functional conveying agent FFM is at the maximum mass fraction of functional conveying agent, how large the temperature glide TG (T" - T) at minus 56 ° C of the mixture of refrigerant and functional conveying agent FFM at the maximum mass fraction of the Functional conveying agent FFM is and how large the maximum triple point reduction of the mixture of refrigerant and functional conveying agent FFM is at the maximum mass fraction based on the pure refrigerant.

However, it is even more advantageous if the FFM functional conveying agent mixed with the refrigerant only causes a triple point reduction compared to the pure refrigerant of less than 3 K and the other specifications remain the same.

Such FFM functional conveyors with the corresponding parameters are listed in Table 2.

It is even more advantageous if the functional conveying agent FFM in the mixture with the refrigerant only results in a reduction of the temperature glide TG (T" - T) by 3 K, as listed in Table 3.

However, it is also possible to allow a larger temperature glide TG (T" - T); these FFM functional conveyors with the corresponding parameters for the respective mixture are listed in Table 4.

Tables 1 to 4 only list data for functional conveyors and lubricants are not taken into account as functional conveyors.

In further embodiments, shown in the Fig. 3 to 12 Additionally or alternatively, the lubricant itself is used as the functional conveying agent FFM, which can be added in doses at various points in the refrigerant circuit.

This is the case in the exemplary embodiment Fig. 3 It is provided to supply the lubricant on the high-pressure side, specifically after the lubricant separator 50 and before the desuperheater 19, to the high-pressure-side refrigerant, which then guides the lubricant through the refrigerant circuit 10 and in particular also through the nozzle channels 34 into the heat exchanger channels 36, so that the lubricant is then introduced into these can carry out its wetting function and improve heat transfer.

To precisely determine the mass fraction of the lubricant in the mixture of lubricant and refrigerant, a lubricant supply line 62 is provided with a metering unit 64 arranged therein, which supplies the lubricant to the refrigerant circuit between the oil separator 50 and the desuperheater 19, so that a via the metering unit 64 precisely metered lubricant circulation rate can be specified.

In a third embodiment, shown in Fig. 4 , the supply of lubricant from the lubricant bath 54 takes place via a supply line 72, in which a metering unit 74 is also provided, the supply line 72 opening into the refrigerant circuit between the desuperheater 19 and the condenser 20 and thus the refrigerant entering the condenser 20 then carries the exactly metered amount of lubricant in the refrigerant circuit, so that the lubricant then also can develop its wetting effect in the heat exchanger channels 36.

In a fourth embodiment, shown in Fig. 5 a supply line 82 is provided, in which a metering unit 84 is also provided, the supply line 82 supplying the lubricant to the refrigerant circuit between the condenser 20 and the control valve 24.

In a fifth embodiment, shown in Fig. 6 a supply line 92 is provided, which is also provided with a metering unit 94 and supplies lubricant from the lubricant bath 54 between the control valve 24 and the heat exchanger 30 or on the input side of the heat exchanger 30 to the refrigerant circuit, so that metering of the lubricant and lubricant is unaffected by the previous components Thus, a very precise lubricant circulation rate in the heat exchanger 30 can be achieved and the wetting function of the lubricant serving as a function-promoting agent can be precisely specified.

In a sixth embodiment, shown in Fig. 7 , the lubricant is supplied from a supply line 102 with a metering unit 104 from the lubricant bath 54 directly to the respective heat exchanger channel 36, for example an area 106 thereof, which is arranged close to the respective nozzle channel 34, preferably following it, so that the Lubricant can mix with the solid phase of the refrigerant that is forming or the refrigerant that is already sublimating and can then have a wetting effect.

For example, in the second to sixth exemplary embodiments, the mass proportions of the lubricant in the heat exchanger channel 36 are at values of 0.11% by mass to 0.05% by mass of the mixture of refrigerant and lubricant entering the heat exchanger 30.

Otherwise, insofar as the second to sixth exemplary embodiments are concerned, reference is made in full to the comments on the first exemplary embodiment.

This is the case in the seventh exemplary embodiment Fig. 8 It is intended to supply refrigerant and the lubricant carried by it to the high-pressure side, namely after the lubricant separator 50 and before the desuperheater 19, to the high-pressure side refrigerant, which then guides the lubricant through the refrigerant circuit 10 and in particular also through the nozzle channels 34 into the heat exchanger channels 36, so that in The lubricant can then carry out its wetting function and improve heat transfer.

To precisely determine the mass fraction of the lubricant in the mixture of lubricant and refrigerant, a supply line 112 with a metering unit 114 arranged therein is provided, which branches off the refrigerant compressed to high pressure with lubricant between the high-pressure side 16 of the refrigerant compressor 12 and the lubricant separator 50 from the refrigerant circuit and, bypassing the lubricant separator 50, supplies it to the refrigerant circuit between the lubricant separator 50 and the desuperheater 19, so that a lubricant circulation rate that can be precisely metered via the metering unit 114 can be specified.

In an eighth embodiment, shown in Fig. 9 , the supply of refrigerant and lubricant branched off in the same way as in the seventh exemplary embodiment takes place via a supply line 122, in which a metering unit 124 is also provided, the supply line 122 opening into the refrigerant circuit between the desuperheater 19 and the condenser 20 and thus the in The refrigerant entering the condenser 20 then precisely metered amount of lubricant is carried in the refrigerant circuit, so that the lubricant can then also develop its wetting effect in the heat exchanger channels 36.

In a ninth embodiment, shown in Fig. 10 a supply line 132 is provided, in which a metering unit 134 is also provided, the supply line 132 supplying the refrigerant and lubricant branched off in the same way as in the seventh exemplary embodiment to the refrigerant circuit between the condenser 20 and the control valve 24, whereby an additional one is optionally used to cool it down Condenser or gas cooler 136 is provided in the supply line 132.

In a tenth embodiment, shown in Fig. 11 a supply line 142 is provided, which is also provided with a metering unit 144 and, in the same way as in the seventh exemplary embodiment, supplies diverted refrigerant and lubricant between the control valve 24 and the heat exchanger 30 or on the inlet side of the heat exchanger 30 to the refrigerant circuit, whereby an additional one is optionally used to cool it down Condenser or gas cooler 136 is provided in the supply line 142, so that a metering of the lubricant that is uninfluenced by the previous components and thus a very precise lubricant circulation rate in the heat exchanger 30 can be achieved and thus the wetting function of the lubricant serving as a function-promoting agent can be precisely specified.

In an eleventh embodiment, shown in Fig. 12 , the refrigerant and lubricant branched off in the same way as in the seventh exemplary embodiment is supplied from a supply line 152 with a metering unit 154 directly to the respective heat exchanger channel 36, for example an area 106 thereof, which is close to the respective nozzle channel 34, preferably following it, is arranged so that the lubricant mixes with the forming solid phase of the refrigerant or the already sublimating refrigerant and then has a wetting effect can be, whereby a condenser or gas cooler 136 is optionally provided in the supply line 152 to cool it down.

For example, in the seventh to eleventh exemplary embodiments, the mass proportions of the lubricant in the heat exchanger channel 36 are between 0.11% by mass and 0.05% by mass of the mixture of refrigerant and lubricant entering the heat exchanger 30.

Tabelle 1

eine Zusammenstellung einer Reihe von Funktionsfördermitteln als Zusatzkältemittel für COz als Kältemittel mit Angabe von deren Masse % und Mol %, des sich dabei für das jeweilige Gemisch aus COz als Kältemittel und Funktionsfördermittel ergebenden "global warming potential", des sich dabei bezogen auf COz ergebenden Temperaturgleits und der sich dabei ergebenden Tripelpunktabsenkung ohne Berücksichtigung von Schmiermittel als Funktionsfördermittel;

Tabelle 2

eine Auswahl der Funktionsfördermittel gemäß Tabelle 1 insoweit, als diese der Vorgabe Rechnung tragen, dass bezogen auf COz als Kältemittel die Tripelpunktabsenkung kleiner 3 K ist;

Tabelle 3

eine Auswahl der Funktionsfördermittel gemäß Tabelle 2 mit der Vorgabe, dass bezogen auf COz als Kältemittel die Tripelpunktabsenkung kleiner 3 K und der Temperaturgleit kleiner 3 K ist;

Tabelle 4

eine Auswahl der Funktionsfördermittel gemäß Tabelle 1, wobei bezogen auf COz als Kältemittel der zulässige Temperaturgleit größer 5 K und kleiner 10 K sein kann;

Otherwise, insofar as the seventh to eleventh exemplary embodiments are concerned, reference is made in full to the statements regarding the first exemplary embodiment.

Table 1

a compilation of a series of functional conveying agents as additional refrigerants for COz as a refrigerant with details of their mass % and mole %, the resulting "global warming potential" for the respective mixture of COz as a refrigerant and functional conveying agent, and the resulting temperature glide based on COz and the resulting triple point reduction without taking lubricant into account as a functional promoting agent;

Table 2

a selection of the functional conveying means according to Table 1 insofar as they take into account the requirement that, based on COz as a refrigerant, the triple point reduction is less than 3 K;

Table 3

a selection of the functional conveying means according to Table 2 with the requirement that, based on COz as a refrigerant, the triple point reduction is less than 3 K and the temperature glide is less than 3 K;

Table 4

a selection of the functional conveying means according to Table 1, whereby, based on COz as a refrigerant, the permissible temperature glide can be greater than 5 K and less than 10 K;

• Nicht giftig, nicht brennbar
• Tripelpunktabsenkung ≤ 5 K
• TG ≤ 5 K
• GWP Gemisch < 150

Tabelle 1 Bezeichnung Gemischkomponente GWP Ashrae 34 Bez. Masseanteil min Masseanteil max Mengenanteil min Mengenanteil max GWP Gemisch TG Tripelpunktabsenkung max - - - Masse % Masse % Mol % Mol % - K K (E)-1,3,3,3-Tetrafluorpropen 1 R1234ze 1 2,0 0,4 0,8 1 5,0 0,3 1,1,1,2-Tetrafluorethan 1430 R134a 1 4,0 0,4 1,8 58 5,0 0,7 1,1-Diflourethen 1 R1132a 1 15,6 0,7 11,3 1 0,0 5,0 2,3,3,3-Tetrafluorpropen 1 R1234yf 1 5,7 0,4 2,3 1 5,0 0,9 Difluormethan 675 R32 1 8,8 0,8 7,5 60 5,0 3,3 Ethan 3 R170 1 8,0 1,5 11,3 1 2,6 5,0 Ethen 4 R1150 1 6,6 1,6 10,0 1 2,6 4,4 Ethin 3 1 3,0 1,7 5,0 1 2,2 2,1 Fluorethen 1 R1141 - 1 8,3 1,0 8,0 0 2,0 3,5 Fluormethan 92 R41 1 8,9 1,3 11,3 9 0,5 5,0 Pentafluorethan 3500 R125 1 4,3 0,4 1,6 150 1,7 0,7 Propan 3 R290 1 7,0 1,0 7,0 1 1,7 3,0 Propen 3 R1270 1 7,7 1,0 8,0 1 3,3 3,5 Xenon 0 1 10,6 0,3 3,8 1 5,0 1,6 Mixtures based on CO ₂

• Non-toxic, non-flammable
• Triple point reduction ≤ 5 K
• TG ≤ 5K
• GWP mixture < 150

Table 1 Name of mixture component GWP Ashrae 34 Ref. Mass fraction min Mass fraction max Proportion min Proportion max GWP mixture TG Triple point reduction max - - - Dimensions % Dimensions % Mol% Mol% - K K (E)-1,3,3,3-Tetrafluoropropene 1 R1234ze 1 2.0 0.4 0.8 1 5.0 0.3 1,1,1,2-Tetrafluoroethane 1430 R134a 1 4.0 0.4 1.8 58 5.0 0.7 1,1-Difluorourethene 1 R1132a 1 15.6 0.7 11.3 1 0.0 5.0 2,3,3,3-Tetrafluoropropene 1 R1234yf 1 5.7 0.4 2.3 1 5.0 0.9 Difluoromethane 675 R32 1 8.8 0.8 7.5 60 5.0 3.3 Ethan 3 R170 1 8.0 1.5 11.3 1 2.6 5.0 Ethen 4 R1150 1 6.6 1.6 10.0 1 2.6 4.4 Ethine 3 1 3.0 1.7 5.0 1 2.2 2.1 Fluoroethene 1 R1141 - 1 8.3 1.0 8.0 0 2.0 3.5 Fluoromethane 92 R41 1 8.9 1.3 11.3 9 0.5 5.0 Pentafluoroethane 3500 R125 1 4.3 0.4 1.6 150 1.7 0.7 propane 3 R290 1 7.0 1.0 7.0 1 1.7 3.0 Propene 3 R1270 1 7.7 1.0 8.0 1 3.3 3.5 xenon 0 1 10.6 0.3 3.8 1 5.0 1.6

• Nicht giftig, nicht brennbar
• Tripelpunktabsenkung ≤ 3 K
• TG ≤ 5 K
• GWP Gemisch < 150

Tabelle 2 Bezeichnung Gemischkomponente GWP Ashrae 34 Bez. Masseanteil min Masseanteil max Mengenanteil min Mengenanteil max GWP Gemisch TG Tripelpunktabsenkung max - - - Masse % Masse % Mol % Mol% - K K (E)-1,3,3,3-Tetrafluorpropen 1 R1234ze 1 2,0 0,4 0,8 1 5,0 0,3 1,1,1,2-Tetrafluorethan 1430 R134a 1 4,0 0,4 1,8 58 5,0 0,7 1,1-Diflourethen 1 R1132a 1 9,7 0,7 6,9 1 0,0 3,0 2,3,3,3-Tetrafluorpropen 1 R1234yf 1 5,7 0,4 2,3 1 5,0 0,9 Difluormethan 675 R32 1 8,0 0,8 6,9 55 4,6 3,0 Ethan 3 R170 1 4,8 1,5 6,9 1 2,3 3,0 Ethen 4 R1150 1 4,5 1,6 6,9 1 2,0 3,0 Ethin 3 1 3,0 1,7 5,0 1 2,2 2,1 Fluorethen 1 R1141 1 7,1 1,0 6,8 0 2,0 3,0 Fluormethan 92 R41 1 5,4 1,3 6,9 6 0,3 3,0 Pentafluorethan 3500 R125 1 4,3 0,4 1,6 150 1,7 0,7 Propan 3 R290 1 7,0 1,0 7,0 1 1,7 3,0 Propen 3 R1270 1 6,6 1,0 6,9 1 2,7 3,0 Xenon 0 1 10,6 0,3 3,8 1 5,0 1,6 Mixtures based on CO ₂

• Non-toxic, non-flammable
• Triple point reduction ≤ 3 K
• TG ≤ 5K
• GWP mixture < 150

Table 2 Name of mixture component GWP Ashrae 34 Ref. Mass fraction min Mass fraction max Proportion min Proportion max GWP mixture TG Triple point reduction max - - - Dimensions % Dimensions % Mol% mol% - K K (E)-1,3,3,3-Tetrafluoropropene 1 R1234ze 1 2.0 0.4 0.8 1 5.0 0.3 1,1,1,2-Tetrafluoroethane 1430 R134a 1 4.0 0.4 1.8 58 5.0 0.7 1,1-Difluorourethene 1 R1132a 1 9.7 0.7 6.9 1 0.0 3.0 2,3,3,3-Tetrafluoropropene 1 R1234yf 1 5.7 0.4 2.3 1 5.0 0.9 Difluoromethane 675 R32 1 8.0 0.8 6.9 55 4.6 3.0 Ethan 3 R170 1 4.8 1.5 6.9 1 2.3 3.0 Ethen 4 R1150 1 4.5 1.6 6.9 1 2.0 3.0 Ethine 3 1 3.0 1.7 5.0 1 2.2 2.1 Fluoroethene 1 R1141 1 7.1 1.0 6.8 0 2.0 3.0 Fluoromethane 92 R41 1 5.4 1.3 6.9 6 0.3 3.0 Pentafluoroethane 3500 R125 1 4.3 0.4 1.6 150 1.7 0.7 propane 3 R290 1 7.0 1.0 7.0 1 1.7 3.0 Propene 3 R1270 1 6.6 1.0 6.9 1 2.7 3.0 xenon 0 1 10.6 0.3 3.8 1 5.0 1.6

• Nicht giftig, nicht brennbar
• Tripelpunktabsenkung ≤ 3 K
• TG ≤ 3 K
• GWP Gemisch < 150

Tabelle 3 Bezeichnung Gemischkomponente GWP Ashrae 34 Bez. Masseanteil min Masseanteil max Mengenanteil min Mengenanteil max GWP Gemisch TG Tripelpunktabsenkung max - - - Masse % Masse % Mol % Mol % - K K (E)-1,3,3,3-Tetrafluorpropen 1 R1234ze 1 1,1 0,4 0,4 1 3,0 0,1 1,1,1,2-Tetrafluorethan 1430 R134a 1 2,3 0,4 1,0 34 3,0 0,4 1,1-Diflourethen 1 R1132a 1 9,7 0,7 6,9 1 0,0 3,0 2,3,3,3-Tetrafluorpropen 1 R1234yf 1 3,3 0,4 1,3 1 3,0 0,5 Difluormethan 675 R32 1 5,0 0,8 4,2 34 3,0 1,8 Ethan 3 R170 1 4,8 1,5 6,9 1 2,3 3,0 Ethen 4 R1150 1 4,5 1,6 6,9 1 2,0 3,0 Ethin 3 1 3,0 1,7 5,0 1 2,2 2,1 Fluorethen 1 R1141 1 7,1 1,0 6,8 0 2,0 3,0 Fluormethan 92 R41 1 5,4 1,3 6,9 6 0,3 3,0 Pentafluorethan 3500 R125 1 4,3 0,4 1,6 150 1,7 0,7 Propan 3 R290 1 7,0 1,0 7,0 1 1,7 3,0 Propen 3 R1270 1 6,6 1,0 6,9 1 2,7 3,0 Xenon 0 1 5,6 0,3 2,0 1 3,0 0,8 Mixtures based on CO ₂

• Non-toxic, non-flammable
• Triple point reduction ≤ 3 K
• TG ≤ 3 K
• GWP mixture < 150

Table 3 Name of mixture component GWP Ashrae 34 Ref. Mass fraction min Mass fraction max Proportion min Proportion max GWP mixture TG Triple point reduction max - - - Dimensions % Dimensions % Mol% Mol% - K K (E)-1,3,3,3-Tetrafluoropropene 1 R1234ze 1 1.1 0.4 0.4 1 3.0 0.1 1,1,1,2-Tetrafluoroethane 1430 R134a 1 2.3 0.4 1.0 34 3.0 0.4 1,1-Difluorourethene 1 R1132a 1 9.7 0.7 6.9 1 0.0 3.0 2,3,3,3-Tetrafluoropropene 1 R1234yf 1 3.3 0.4 1.3 1 3.0 0.5 Difluoromethane 675 R32 1 5.0 0.8 4.2 34 3.0 1.8 Ethan 3 R170 1 4.8 1.5 6.9 1 2.3 3.0 Ethen 4 R1150 1 4.5 1.6 6.9 1 2.0 3.0 Ethine 3 1 3.0 1.7 5.0 1 2.2 2.1 Fluoroethene 1 R1141 1 7.1 1.0 6.8 0 2.0 3.0 Fluoromethane 92 R41 1 5.4 1.3 6.9 6 0.3 3.0 Pentafluoroethane 3500 R125 1 4.3 0.4 1.6 150 1.7 0.7 propane 3 R290 1 7.0 1.0 7.0 1 1.7 3.0 Propene 3 R1270 1 6.6 1.0 6.9 1 2.7 3.0 xenon 0 1 5.6 0.3 2.0 1 3.0 0.8

• Nicht giftig, nicht brennbar
• Tripelpunktabsenkung ≤ 5 K
• T6 < 10 K und ≥ 5 K
• GWP Gemisch < 150

Tabelle 4 Bezeichnung Gemischkomponente GWP Ashrae 34 Bez. Masseanteil min Masseanteil max Mengenanteil min Mengenanteil max GWP Gemisch TG Tripelpunktabsenkung max - - - Masse % Masse % Mol % Mol% - K K (E)-1,3,3,3-Tetrafluorpropen 1 R1234ze 1 5 0 2 1 10,0 0,8 1,1,1,2-Tetrafluorethan 1430 R134a 1 9 0 4 124 10,0 1,7 2,3,3,3-Tetrafluorpropen 1 R1234yf 1 12 0 5 1 10,0 2,2 Xenon 0 1 20 0 8 1 7,5 3,4 Mixtures based on CO ₂

• Non-toxic, non-flammable
• Triple point reduction ≤ 5 K
• T6 < 10 K and ≥ 5 K
• GWP mixture < 150

Table 4 Name of mixture component GWP Ashrae 34 Ref. Mass fraction min Mass fraction max Proportion min Proportion max GWP mixture TG Triple point reduction max - - - Dimensions % Dimensions % Mol% mol% - K K (E)-1,3,3,3-Tetrafluoropropene 1 R1234ze 1 5 0 2 1 10.0 0.8 1,1,1,2-Tetrafluoroethane 1430 R134a 1 9 0 4 124 10.0 1.7 2,3,3,3-Tetrafluoropropene 1 R1234yf 1 12 0 5 1 10.0 2.2 xenon 0 1 20 0 8th 1 7.5 3.4

Claims (16)

Refrigerant circuit (10), comprising a refrigerant compressor (12), which compresses refrigerant to a high pressure level that is above the triple point of the refrigerant, and from which the compressed refrigerant is fed to a heat exchanger unit (18), which removes heat from the refrigerant the heat exchanger unit (18) has an expansion element (34) arranged subsequently, to which at least one heat exchanger channel (36) is connected, the expansion element (34) expanding the compressed refrigerant in such a way that the triple point in the expansion element itself is not exceeded and that the refrigerant Leaving the expansion element in the subsequent heat exchanger channel (36) falls below the triple point and sublimates and thereby absorbs heat from a heat source (28) surrounding a heat exchanger body (40) having the heat exchanger channel (36), as well as a heat source which absorbs the refrigerant after leaving the heat exchanger channel (36). and the collecting line (38) supplying the refrigerant compressor (12),
characterized in that a mixture of refrigerant and a functional conveying agent (FFM) flows through the heat exchanger channel (36), that when the refrigerant sublimates, the functional conveying agent (FFM) is still present as a liquid functional conveying agent (FFM), which undergoes heat transfer in the heat exchanger channel (36). between the sublimating refrigerant and the heat exchanger body (40) having the heat exchanger channel (36). Refrigerant circuit according to claim 1, characterized in that a lubricant separator (50) is arranged between the refrigerant compressor (12) and the high-pressure side heat exchanger unit (18), in particular that the lubricant separator (50) is a coalescence separator. Refrigerant circuit according to one of the preceding claims,
characterized in that the functional conveying agent (FFM) is selected so that the mixture of the refrigerant and the functional conveying agent (FFM) is non-flammable. Refrigerant circuit according to one of the preceding claims,
characterized in that the functional conveying agent (FFM) is selected such that the mixture of the refrigerant and the functional conveying agent (FFM) has a triple point that is lowered by a maximum of 5 K, preferably a maximum of 3 K, compared to the triple point of the pure refrigerant. Refrigerant circuit according to one of the preceding claims,
characterized in that the functional conveying agent (FFM) is selected such that the mixture of the refrigerant and the functional conveying agent (FFM) in the area between the triple point and the critical point has a temperature glide (TG), that is, a difference between the dew temperature (T " ) and the boiling temperature (T), which is a maximum of 5 K, preferably a maximum of 3 K. Refrigerant circuit according to one of the preceding claims,
characterized in that the functional conveying agent (FFM) is selected such that the mixture of the refrigerant and the functional conveying agent (FFM) has a “global warming potential” (GWP) of less than 150. Refrigerant circuit according to one of the preceding claims,
characterized in that the proportion of the functional conveying agent (FFM) in the mixture of refrigerant and functional conveying agent (FFM) is selected such that no blockage occurs in the heat exchanger channel (36) during the sublimation of the refrigerant. Refrigerant circuit according to one of the preceding claims,
characterized in that the functional conveying agent (FFM) in the refrigerant circuit (10) comprises a lubricant flowing through at least the heat exchanger channel (36), in particular with a defined mass proportion of the total mass of the mixture of refrigerant and functional conveying agent (FFM). Refrigerant circuit according to claim 8, characterized in that the refrigerant circuit (10) is metered with lubricant from the lubricant separator ( 50) is supplied as a functional support agent (FFM). Refrigerant circuit according to claim 8 or 9, characterized in that the refrigerant circuit (10) is supplied by means of a supply line (112, 122, 132, 142, 152) branching off between the refrigerant compressor (12) and the lubricant separator (50) and a metering unit (114) assigned thereto , 124, 134, 144, 154) a mixture of refrigerant and lubricant is metered in as a functional conveying medium (FFM). Refrigerant circuit according to one of claims 8 to 10, characterized in that the refrigerant circuit (10) is supplied with metered lubricant as a functional conveying medium (FFM) in the area of the high-pressure side heat exchanger unit (18). Refrigerant circuit according to one of claims 8 to 11, characterized in that the refrigerant circuit (10) in the area of the expansion element (34) is supplied with lubricant in a metered manner as a functional conveying agent (FFM). Refrigerant circuit according to one of claims 8 to 12, characterized in that lubricant is fed to the refrigerant circuit (10) in a metered manner as a functional conveying medium (FFM) to the exclusion of the expansion element (34). Refrigerant circuit according to one of the preceding claims, characterized in that in the heat exchanger channel (36) the mass fraction of the lubricant present in the mixture, based on the total mass of the mixture of refrigerant and functional conveying agent (FFM), is more than 0.02 mass%, preferably more than 0, 04 mass%, in particular that a heat exchanger channel (36) the mass proportion of the lubricant present in the mixture based on the total mass of the mixture of refrigerant and functional conveying agent (FFM) is a maximum of 1 mass%, better maximum 0.11 mass%, even better maximum 0.05% by mass. Refrigerant circuit according to one of the preceding claims, characterized in that the functional conveying agent (FFM) comprises at least one additional refrigerant, in particular that the proportion of the additional refrigerant representing the functional conveying agent (FFM) in the mixture of refrigerant and functional conveying agent (FFM) is selected such that the mixture of refrigerant and functional conveying agent (FFM) in the area between the triple point and the critical point has a temperature glide (TG) that is less than 5 K, and, based on the pure refrigerant, has a triple point reduction that is less than 5 K, and in particular not is flammable and in particular also a "global warming potential" (GWP) is less than 150, in particular that the functional conveying agent (FFM) has one or more of the additional refrigerants (E)-1,3,3,3-tetrafluoropropene, 1,1,1,2-tetrafluoroethane, 1,1-difluoroethene , 2,3,3,3-tetrafluoropropene, difluoromethane, ethane, ethene, ethyne, fluoroethene, fluoromethane, pentafluoroethane, propane, propene, xenon. Refrigerant circuit according to one of the preceding claims, characterized in that the refrigerant is COz, in particular that the refrigerant COz has a mass fraction in the range from 80 mass% to 99 mass% based on the total mass of the mixture of the refrigerant COz and the functional conveying agent (FFM). , and/or that the refrigerant COz has a molar proportion in the range of 88 mol% to 99.6 mol% based on 100 mol% of the mixture of the refrigerant COz and the functional conveying agent (FFM).

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