EP2606291B1 - Coolant condenser assembly - Google Patents

Description

The present invention relates to a refrigerant condenser assembly according to the preambles of claim 1.

In refrigerant condenser assemblies for a power tool air conditioning system, vaporous refrigerant is converted into a liquid state of aggregation and then the liquid refrigerant is further "subcooled" in a subcooling region. The refrigerant condenser assembly forms part of a refrigeration circuit of an automotive air conditioning system with an evaporator, an expansion device and a compressor.

The DE 10 2007 018 722 A1 shows a condenser for the air conditioning system of a motor vehicle having two manifolds and a container arranged adjacent to the one collecting tube for receiving the desiccant of the refrigerant of the air conditioner.

When using the new refrigerant R1234yf in comparison to the previous refrigerant R134a, due to changed material properties of the new refrigerant R1234yf, the refrigeration cycle of an automotive air conditioning system is reduced by up to 10%. The performance of a refrigeration circuit in a Kraftfahrzeugklirnaanlage can be increased inter alia, that at a subcooling of the refrigerant condenser assembly, the already liquefied refrigerant is cooled more.

In a refrigerant condenser assembly, the refrigerant in gaseous form enters the refrigerant condenser assembly at an inlet port and is cooled to a saturation temperature at an overheat region. Subsequently, the refrigerant flows into a condensation region and in this the gaseous refrigerant is further cooled and liquefied. Subsequently, the liquid refrigerant flows into a subcooling region and is cooled below the boiling point, for example to a temperature of 6 or 7 K below the boiling temperature of the refrigerant. By a greater cooling of the refrigerant in the Uhterkühlungsbereich below the boiling point of the refrigerant higher power of the refrigerant circuit can be achieved. In general, however, the refrigerant capacitor assembly within the motor vehicle, a predetermined space, for example given by a certain depth, height and width available, so that although a greater cooling of the refrigerant at the subcooling by a larger surface at the subcooling and a larger space associated therewith Although refrigerant condenser assembly is possible, but in general due to the predetermined dimensions of the space for the refrigerant condenser assembly no larger space is available.

To increase the performance of the refrigerant circuit or to compensate for the reduced performance of the refrigerant, in particular the refrigerant R1234yf, the aim is to increase the subcooling to, for example, 15 K. For this purpose, more cooling tubes or proportionally more area required by the capacitor. This has the consequence that less space is available for the condensation area, the cooling takes place at a higher saturation temperature and the associated saturation pressure increases. This causes a negative effect on the cooling capacity in the refrigeration cycle, which reduces or even nullifies the desired advantage.

Therefore, the object of the present invention is to provide a refrigerant condenser assembly in which the refrigerant is strongly cooled in a subcooling region of the refrigerant condenser assembly without substantially increasing the condensing pressure in the refrigerant condenser assembly.

This object is achieved with a refrigerant condenser assembly for an automotive air conditioning system comprising cooling tubes for passing a refrigerant, two header tubes for fluidly connecting the cooling tubes, preferably a header with at least one overflow opening by means of which the header is in fluid communication with the cooling tubes and / or a header, the cooling tubes an overheating section for cooling the vapor refrigerant, a condensing section for condensing the refrigerant as at least a parallel section, and a subcooling section as a subcooler parallel section for cooling the liquid refrigerant, wherein the flow cross sectional areas of the cooling tubes, particularly all of the cooling tubes, of the subcooling section are smaller than the product of 0.9 or 0.7 or 0.5 and the flow cross-sectional areas of the cooling tubes, in particular of all cooling tubes, the overheating area and / or the condensation area. The flow cross-sectional area is the cross-sectional area of the cooling tubes for passing the refrigerant. The cooling tubes of the subcooling region thus have a smaller flow cross-sectional area than the cooling tubes of the overheating region and / or the condensation region. A smaller flow cross-sectional area can be achieved, for example, by cooling tubes with a smaller cross-sectional area or by cooling tubes with the same cross-sectional area, wherein turbulence inserts in the cooling tubes of the sub-cooling area reduce the flow cross-sectional area.

As a result, an equal volume flow of the refrigerant occurs in the cooling tubes of the subcooling region as in the cooling tubes of the overheating region and / or the condensation region, so that the heat can be better transferred from the refrigerant to the air. Thus, the refrigerant can be cooled more advantageously at the subcooling, for example, to a temperature of 14 K below the boiling temperature of the refrigerant without thereby increasing the dimensions of the refrigerant condenser assembly and thus the refrigerant condenser assembly finds place in a given space of a motor vehicle. Thus, the performance of a refrigeration circuit of an automotive air conditioning system can be improved and thereby the power reduction when using the new refrigerant R1234yf be at least partially compensated.

An increased pressure drop in the subcooling area is not detrimental to the performance of the refrigerant condenser assembly or performance reducing. This is due to the fact that the pressure drop takes place after the wet steam area, while the system's high pressure is oriented at the saturation temperature before the subcooling area or after the condensation area.

In a variant, in the subcooling region, at least two cooling tubes act as the first subcooler in parallel with the refrigerant, the refrigerant flowing out of the first subcooler enters into a first subcooling passage and the first subcooling passage opens into at least two cooling tubes as the second subcooler and preferably flows into the subcooling region second subcooling parallel section into a second subcooling intermediate flow channel and the second subcooling intermediate flow channel opens into at least two cooling tubes as the third subcooler parallel section. The subcooling region of the refrigerant condenser assembly is thus divided into a total of two or three subcooler parallel sections, each interconnected by the subcooling intercooler passage. As a result, the refrigerant at the subcooling region can be cooled even further below the boiling point of the refrigerant.

The subcooling region of the refrigerant condenser assembly is thus subdivided into a first and a second subcooler parallel section, and in the subcooler parallel sections, at least two cooling tubes are respectively hydraulically or fluid-conductively supplied in parallel with the refrigerant. In this case, the refrigerant exiting from the first subcooler parallel section is introduced into and mixed in a first subcooling intermediate flow channel, and the refrigerant is introduced into the second subcooler parallel section from the first subcooling intermediate flow channel. In the refrigerant condenser assemblies known from the prior art, the refrigerant is conducted in parallel in the subcooling region, for example, by four, seven or nine cooling tubes. In the refrigerant condenser assembly according to the invention, the first and second subcooler parallel sections have, for example, two, three or five cooling tubes. As a result, the refrigerant has a smaller flow cross-sectional area at the first and second subcooler parallel sections as in the refrigerant condenser assembly known in the art, thereby causing a larger flow velocity of the refrigerant to occur at the subcooling region and thereby improve or increase the heat transfer from the refrigerant to the air flowing around the refrigerant condenser assembly.

In a further embodiment, one subcooler parallel section or the subcooling region between two or eight cooling tubes acted upon in parallel and / or the surface of the cooling tubes and preferably the headers of the subcooling region is less than 50%, 40%, 35%, 30%, 25% or 15% of the surface of the heat exchanger of the refrigerant condenser assembly and in particular, the heat exchanger consists of the cooling tubes and preferably the headers.

In a supplementary embodiment, in the flow direction of the refrigerant before the first subcool parallel section, at least two cooling tubes are acted upon as a first parallel section in a fluid-conducting manner in parallel. The refrigerant flowing out of the first parallel section opens into a first intermediate flow channel and the first intermediate flow channel opens into at least two cooling tubes as the second parallel section. In the flow direction of the refrigerant before the first subcooler parallel section, ie before the subcooling region of the refrigerant condenser group, ie thus at the overheating region and / or at the condensation region of the refrigerant condenser assembly is thus arranged a first and a second parallel section. Thus, the overheating region and / or the condensation region are subdivided into the first and second subcooler parallel sections between which the refrigerant is conducted through the first intermediate flow channel.

In a supplementary embodiment, in the flow direction of the refrigerant before the first subcooler parallel section, the refrigerant flowing out of the second parallel section opens into a second intermediate flow channel and the second intermediate flow channel opens into at least two cooling tubes as the third parallel section. Before the subcooling area, d. H. Thus, at the overheating region and / or at the condensation region of the refrigerant condenser assembly, thus the refrigerant condenser assembly is divided into a total of three parallel sections with at least two, preferably at least four or six or eight, cooling tubes, which are each fluid-conductively connected to each other through the intermediate flow channel. Preferably, a parallel section has a greater number of cooling tubes than a subcooler parallel section, and preferably the number of cooling tubes of a parallel section is two, three, five or seven cooling tubes greater than the number of cooling tubes of a subcooler parallel section.

Preferably, the second parallel section opens into a second intermediate flow channel and the second intermediate flow channel opens into the collecting container or the third parallel section opens into a third intermediate flow channel and the third intermediate flow channel opens into the collecting container. If the overheating and / or condensation region of the refrigerant condenser assembly has the first and second parallel sections, then the refrigerant discharged from the second parallel section is introduced into the first subcooler section, or the overheating and / or condenser section has three parallel sections, that of the third parallel section discharged refrigerant introduced into the first subcooler parallel section, wherein in each case between condensing region and subcooling of the collecting container is arranged. This also applies analogously if the overheating and / or condensation region is subdivided into more than three parallel sections, for example four or five parallel sections.

In one variant, the sum of the flow cross-sectional areas of all the cooling tubes of a subcooler parallel section is smaller than the product of 1.0 or 0.9 or 0.7 or 0.5 or 0.3 or 0.1 and the sum of the flow cross-sectional areas of all the cooling tubes of a parallel section and / or the cooling tubes are formed as flat tubes and corrugated ribs are arranged between the flat tubes. Thus, in particular, the filling amount of refrigerant can be reduced. Thus, especially for refrigerant circuits with the expensive refrigerant R1234yf the cost can be reduced.

In one variant, the width of the cooling tubes, in particular of all cooling tubes, a subcooling parallel section or the subcooling region is smaller than the product of 1.0 or 0.9 or 0.7 or 0.5 or 0.3 or 0.1 and the width of the Cooling tubes, in particular all cooling tubes, a parallel section.

Regardless, the heat transfer in the subcooling can also be controlled by the individual corrugated fins, which are arranged between the individual cooling tubes. According to the invention, it is therefore proposed that the corrugated fins have a different geometry in the subcooling region than the corrugated fins in the overheating region and / or condensation region. In this case, the corrugated fins in the subcooling region are preferably designed such that the air-side heat transfer in this region increases or improves.

For example, the corrugated fins in the subcooling region could be of the same height as in the overheating region and / or condensation region, but have a different geometry due to increased corrugated rib density or gill fields, which improves the heat transfer in this region.

Alternatively, the corrugated fins in the subcooling region could be designed with a lower height than in the overheating region and / or condensation region.

Alternatively, narrower cooling tubes could be used in the subcooling area in order to increase the flow velocity and thus the heat transfer.

Alternatively, the corrugated fins could be designed in the subcooling with a higher height than in the overheating area and / or condensation area. In this case, the air-side heat transfer would be deteriorated. However, since fewer cooling tubes are arranged in parallel on the refrigerant side, the heat transfer on the refrigerant side would increase.

Also described is a method for operating a refrigeration cycle of an automotive air conditioning system comprising the steps of: passing refrigerant through conduits of a refrigerant circuit, compressing the gaseous refrigerant in a compressor so that the pressure of the gaseous refrigerant is increased, cooling and condensing the gaseous refrigerant in a refrigerant condenser assembly passed through cooling tubes by cooling the gaseous refrigerant in an overheating region to a saturation temperature, then cooling and liquefying the gaseous refrigerant to a boiling temperature in a condensation region and cooling the liquid refrigerant below the boiling temperature in a subcooling region; expanding the liquid Refrigerant on an expansion device, so that the pressure of the liquid refrigerant is reduced, heating and evaporation of the refrigerant in an evaporator, Le In the subcooling region, the refrigerant flows through cooling tubes with a smaller flow cross-sectional area into the gaseous refrigerant exiting from the evaporator to the compressor is passed as the refrigerant which is passed through the cooling tubes of the superheating region and / or the condensation region, so that the refrigerant passed through the cooling tubes in the subcooling region has an equal volume flow as the refrigerant conducted in the superheating region and / or the condensation region through the cooling tubes ,

Conveniently, in the subcooling area, the refrigerant is passed in parallel through at least two cooling pipes of a first subcooler parallel section, the refrigerant flowing out of the first subcooling section is directed into a first subcooling intermediate channel, and the refrigerant passed through the first subcooling air channel is then passed in parallel through at least two cooling pipes of a second subcooler parallel section / or the condensation region and / or the refrigerant in the subcooling region is cooled by more than 7, 10, 12 or 14 K and is preferably cooled by less than 30 K or 20 K. Due to the large volume flow of the refrigerant in the cooling tubes of the subcooling region and the associated greater flow velocity of the refrigerant in the subcooling region, this can achieve better heat transfer from the refrigerant to the air flowing around the refrigerant condenser assembly.

In a further development, an automotive air conditioning system comprises a refrigerant condenser assembly, an evaporator, a compressor, preferably a blower, preferably a housing for accommodating the blower and the evaporator, the chill condenser assembly being a refrigerant condenser assembly described in this specification is formed and / or the vehicle air conditioning system described in this description method is executable.

In an additional embodiment, the refrigerant is R1234yf or R134a.

In a variant, the refrigerant condenser assembly has a closure device formed on the collecting container for closing a closure opening of the collecting container.

Preferably, a dryer and / or a filter are arranged in the collecting container and / or in the closure device.

Fig. 1

eine perspektivische Ansicht einer Kältemittelkondensatorbaugruppe,

Fig. 2

eine perspektivische Teilansicht der Kältemittelkondensatorbaugruppe gemäß Fig. 1 und

Fig. 3

ein Strömungsschaltbild des Kältemittels in der Kältemittelkondensatorbaugruppe gemäß Fig. 1.

In the following, an embodiment of the invention will be described in more detail with reference to the accompanying drawings. It shows:

Fig. 1

a perspective view of a refrigerant condenser assembly,

Fig. 2

a partial perspective view of the refrigerant condenser assembly according to Fig. 1 and

Fig. 3

a flow diagram of the refrigerant in the refrigerant condenser assembly according to Fig. 1 ,

In FIG. 1 and 2 a refrigerant condenser assembly 1 is shown in a perspective view. The refrigerant condenser assembly 1 is part of an automotive air conditioning system with an evaporator and a compressor (not shown). By horizontally arranged cooling tubes 2 as flat tubes 3 flows to be condensed and cooled refrigerant ( Fig. 1 and 2 ). The cooling tubes 2 open at their respective ends in a vertical manifold 5, that is, there are two manifolds 5 respectively at the ends of the cooling tubes 2. In Fig. 2 only one manifold 5 is shown. For this purpose, the collecting tube 5 has cooling tube openings through which the ends of the cooling tubes 2 project into the collecting tube 5. Within the manifolds 5 baffles (not shown) are formed with which a certain flow path of the refrigerant can be achieved through the cooling tubes 2, so that the refrigerant through the cooling tubes 2 according to the flow diagram in Fig. 3 flows through the cooling tubes 2.

Between the cooling tubes 2 meandering corrugated fins 4 are arranged, which are in thermal communication with the cooling tubes 2 by means of heat conduction. This increases the area available for cooling the refrigerant. The cooling tubes 2, the corrugated fins 4 and the two manifolds 4 are generally made of metal, in particular aluminum, and are materially connected together as a solder joint. In four corner regions of the Kältemittelkondensalorbaugruppe 1, a fastening device 8 is arranged, with which the Kälternittelkondensatorbaugruppe on a motor vehicle, in particular on a body of a motor vehicle, can be attached.

At the manifold 4, also vertically aligned, a collecting container 6 is arranged ( Fig. 1 . 2 ). The collecting container 6 is by means of two overflow openings (not shown) in fluid communication with the collecting tube 5 and thus also indirectly in fluid communication with the cooling tubes 2. In the collecting container 6, a dryer and a filter (not shown) is arranged. The dryer is hygroscopic and can absorb water or moisture from the refrigerant. The collecting container 6 is mechanically connected to the collecting tube 5 at the lower and upper ends with a concave support region. At the lower end of the collecting container 6 is closed by a closure device 7 fluid-tight. The removable closure device 7 allows replacement of the dryer and filter in the sump 6.

The refrigerant condenser assembly 1 has an inlet port 9 for introducing the refrigerant R1234yf into the refrigerant condenser assembly 1, and an outlet port 10 for discharging the refrigerant from the refrigerant condenser assembly 1 (FIG. Fig. 1 and 3 ). The ends of the cooling tubes 2 terminate in the manifolds 5. In the manifolds 5 baffles or flow guide plates, not shown, are arranged by means of which a certain predetermined flow diagram of the refrigerant can be achieved, ie with which flow path the refrigerant through the plurality of stacked Cooling tubes 2 of the refrigerant condenser assembly 1 flows. This in Fig. 3 The illustrated flow pattern serves only to illustrate the flow path of the refrigerant through the cooling tubes 2 and does not represent a geometric orientation of the cooling tubes 2 to each other in the refrigerant capacitor assembly 1. A first intermediate flow passage 20, a second intermediate flow passage 22, a third intermediate flow passage 24 and a first sub-cooling intermediate flow passage 15th , what a Fig. 3 are shown are thus formed within the manifolds 5 of the flow guide plates, not shown.

The refrigerant condenser assembly 1 constitutes a heat exchanger for transferring heat from the refrigerant to air surrounding and circulating around the refrigerant condenser assembly 1. In this case, the heat exchanger is essentially formed by the cooling tubes 2 and the two manifolds 5. The heat exchanger as part of the refrigerant condenser assembly 1 in this case has an inlet opening 9 through which gaseous refrigerant is passed from a compressor, not shown, to the refrigerant condenser assembly 1. The gaseous refrigerant is at an overheating region 11 to a saturation temperature cooled, ie at the saturation temperature occurs according to the existing pressure, a condensation of the refrigerant. In the flow direction of the refrigerant after the overheating region 11, a condensation region 12 follows, in which the refrigerant is condensed and thus liquefied. The refrigerant liquefied in the condensation region 12 is supplied as liquid to the subcooling region 13 and cooled in the subcooling region 13 below the boiling temperature of the refrigerant. In the Fig. 3 predetermined clear separation in the overheating region 11, condensation region 12 and subcooling region 13 may differ slightly during operation of an automotive air conditioning system, so that, for example, in a modification of the illustration in FIG Fig. 3 the overheating region 11 is slightly larger and thereby the condensation region 12 becomes smaller, so that, for example, a second parallel section 21 also partially forms the overheating region 11.

Alternatively, it is also possible for the overheating region and the condensation region to be arranged in exactly one parallel section.

This applies analogously to the separation between the condensation region 12 and the subcooling region 13, which can either shift into a first subcooling parallel section 14 in the flow direction of the refrigerant or in a third parallel section 23 against the flow direction of the refrigerant.

The overheating region 11 is formed by the first parallel section 19. The first parallel section 19 has eleven cooling tubes which are connected in parallel or flow through in a fluid-conducting or hydraulic manner. After flowing out of the refrigerant from the eleven cooling tubes 2 of the first parallel section 19, the refrigerant is introduced into the first intermediate flow passage 20 and introduced from the first intermediate flow passage 20 into the second parallel section 21. The second parallel section 21 has eight cooling tubes 2, through which the refrigerant flows simultaneously in parallel. The refrigerant flowing out of the second parallel section 21 is introduced into the second intermediate flow passage 22 and introduced therefrom into the third parallel section 23 with likewise eight cooling tubes 2.

The refrigerant flowing out of the third parallel section 23 is introduced into the third intermediate flow passage 24, and is then supplied to the subcooling section 13 of the refrigerant condenser assembly 1. The subcooling region 13 comprises a first subcooling parallel section 14 and a second subcooling parallel section 16. The two subcooler parallel sections 14, 16 each have six cooling tubes 2. The first sub-cooling parallel section 14 is connected to the second sub-cooling parallel section 16 through the first sub-cooling intermediate flow passage 15. Thus, in the refrigerant condenser assembly 1, the parallel sections 19, 21 and 23 and the subcooler parallel sections 14, 16 are fluidly connected in series and the cooling tubes 2 at the parallel sections 19, 21 and 23 and at the subcool parallel sections 14, 16 and 18 are hydraulically or fluidly parallel connected.

The entire refrigerant passed through the refrigerant condenser assembly 1 thus flows through the respective parallel sections 19, 21 and 23 and the subcooler parallel sections 14, 16. The subcooler parallel sections 14, 16 have a smaller number of cooling tubes 2 than the parallel sections 19, 21 and 23. In addition the flow cross-sectional area of the cooling tubes 2 of the subcooler parallel sections 14, 16 smaller than the flow cross-sectional area of the cooling tubes 2 of the parallel sections 19, 21 and 23, because the width of the cooling tubes 2 as flat tubes 3 at the parallel sections 19, 21, 23 1.8 mm and the width of Cooling tubes 2 at the subcooler parallel sections 14, 16 is 1.3 mm. Further, the distance between the cooling tubes 2 in the sub-cooling parallel sections 14, 16 with 6 mm smaller than the distance between the cooling tubes of the parallel sections 19, 21, 23 with 8 mm, so that the height of the corrugated fins 4 at the parallel sections 19, 21, 23 with 8 mm is greater than the height of the corrugated fins 4 at the sub-cooling parallel sections 14, 16 with 6 mm. The width of the cooling tubes 2 in this case represents the expansion in a cross section of the cooling tubes 2 and the length of the cooling tubes 2 in the cross section corresponds to the depth of the refrigerant condenser assembly 1 to the cooling tubes 2, ie the expansion in the flow direction of the air passing through between the cooling tubes 2 the refrigerant condenser assembly 1 flows.

Due to the fluid-conducting or hydraulic circuit of the refrigerant condenser assembly 1 is thus the refrigerant at the subcooler parallel sections 14, 16 a much smaller flow cross-sectional area than at the parallel sections 19, 21 and 23, because the cooling tubes 2 have different flow cross-sectional areas and further the number of cooling tubes. 2 is preferably smaller at the subcooler parallel sections 14, 16 than at the parallel sections 19, 21, and 23. As a result, the flow velocity is adjusted according to the density change. Due to the high velocity of the refrigerant at the subcooling region 13 compared to a subcooling region having only one subcooling parallel portion, the heat transfer from the refrigerant to the air in the subcooling region 13 can be increased, thereby transferring more heat from the refrigerant to the air flowing around the refrigerant condenser assembly 1 Thus, the refrigerant in the subcooling 13 are cooled more below the boiling temperature of the refrigerant, for example, be cooled by 14 K below the boiling temperature of the refrigerant. This can be increased advantageously the COP of a refrigerant circuit. Due to the adequately dimensioned flow cross-sectional area at the subcooling region 13, the pressure drop in the refrigerant condenser assembly 1 is not or only very slightly increased, so that the high pressure at the inlet opening 9 only slightly increases and thus the performance increase of the refrigeration circuit due to the greater cooling at the subcooling region 13 is substantially greater than the power reduction due to the possible increase of the high pressure at the inlet opening 9 is.

In a further exemplary embodiment (not shown), the subcooling region 13, in addition to the first and second subcooling parallel sections 14, 16, also has a third subcooling parallel section. In an additional embodiment, not shown, the overheating and condensation region 11, 12 may have only one or two parallel sections 19, 21.

Overall, significant advantages are associated with the inventive refrigerant capacitor assembly 1. The volume flow at the subcooling region 13 is greatly increased due to the smaller flow cross sectional area of the cooling tubes 2 in the subcooling region 13, and preferably because of the predetermined flow diagram, so that a stronger subcooling or cooling of the refrigerant can be achieved at the subcooling region 13 without the refrigerant condenser assembly 1 more Required space or surface, because due to the larger volume flow, the heat transfer from the refrigerant per surface unit of the refrigerant condenser assembly 1, in particular to the cooling tubes 2, the corrugated fins 4 or the manifolds 5 as a heat exchanger of the refrigerant condenser assembly 1, is increased. As a result, with an unchanged installation space for the refrigerant condenser assembly 1, the COP of a refrigeration circuit with the refrigerant condenser assembly 1 can be increased without requiring additional space for the refrigerant condenser assembly 1. Thus, the reduction in COP due to the use of the refrigerant R1234yf can be at least partially compensated.

LIST OF REFERENCE NUMBERS

1

Refrigerant condenser assembly

2

cooling pipe

3

flat tube

4

corrugated fin

5

manifold

6

Clippings

7

Closing device on the collecting container

8th

fastening device

9

inlet port

10

outlet

11

overheating area

12

condensation region

13

Unterkühlungshereich

14

First subcooler parallel section

15

First subcooler intermediate flow channel

16

Second subcooling parallel step

17

-

18

-

19

First parallel section

20

First intermediate flow channel

21

Second parallel section

22

Second intermediate flow channel

23

Third parallel section

24

Third intermediate flow channel

Claims (9)

1. A refrigerant condenser assembly (1) for a motor vehicle air-conditioning system, comprising

   - cooling tubes (2) for conducting a refrigerant,

   - two collecting tubes (5) for fluidically connecting the cooling tubes (2),

   - preferably a collecting tank (6) having at least one flow transfer opening via which the collecting tank (6) is fluidically connected to the cooling tubes (2) and/or to the collecting tube (5),

   - the cooling tubes (2) have a superheat region (11) for cooling the vaporous refrigerant, a condensation region (12) for condensing the refrigerant as at least one parallel portion (19, 21, 23), and a supercooling region (13) as a supercooling parallel portion for cooling the liquid refrigerant,

   characterised in that
   the flow cross-sectional areas of the cooling tubes (2) of the supercooling region (13) are less than the product of 0.9 or 0.7 or 0.5 and the flow cross-sectional areas of the cooling tubes (2) of the superheat region (11) and the condensation region (12) .
2. The refrigerant condenser assembly as claimed in claim 1, characterised in that in the supercooling region (13), at least two cooling tubes (2) as a first supercooling parallel portion (14) are charged with the refrigerant in parallel in terms of fluid conduction, the refrigerant flowing out of the first supercooling parallel portion (14) issues into a first supercooling intermediate flow duct (15), and the first supercooling intermediate flow duct (15) issues into at least two cooling tubes (2) as a second supercooling parallel portion (16) and preferably, in the supercooling region (13), the second supercooling parallel portion (16) issues into a second supercooling intermediate flow duct and the second supercooling intermediate flow duct issues into at least two cooling tubes (2) as a third supercooling parallel portion.
3. The refrigerant condenser assembly as claimed in claim 1 or 2, characterised in that in each case one supercooling parallel portion (14, 16) or the supercooling region (13) has between two or eight cooling tubes (2) which are charged in parallel, and/or the surface area of the cooling tubes (2) and preferably of the collecting tubes (5) of the supercooling region (13) amounts to less than 50%, 40%, 35%, 30%, 25% or 15% of the surface area of the heat exchanger of the refrigerant condenser assembly (1), and in particular, the heat exchanger is composed of the cooling tubes (2) and preferably the collecting tubes (5).
4. The refrigerant condenser assembly as claimed in one or more of the preceding claims, characterised in that, upstream of the first supercooling parallel portion (14) as viewed in the flow direction of the refrigerant, at least two cooling tubes (2) as a first parallel portion (19) are charged in parallel in terms of fluid conduction, the refrigerant flowing out of the first parallel portion (19) issues into a first intermediate flow duct (20), and the first intermediate flow duct (20) issues into at least two cooling tubes (2) as a second parallel portion (21).
5. The refrigerant condenser assembly as claimed in claim 4, characterised in that, upstream of the first supercooling parallel portion (14) as viewed in the flow direction of the refrigerant, the refrigerant flowing out of the second parallel portion (21) issues into a second intermediate flow duct (22), and the second intermediate flow duct (22) issues into at least two cooling tubes (2) as a third parallel portion (23).
6. The refrigerant condenser assembly as claimed in claim 4 or 5, characterised in that the second parallel portion (21) issues into a second intermediate flow duct (22) and the second intermediate flow duct (22) issues into the collecting tank, or the third parallel portion (23) issues into a third intermediate flow duct (24) and the third intermediate flow duct (24) issues into the collecting tank.
7. The refrigerant condenser assembly as claimed in one or more of the preceding claims, characterised in that the sum total of the flow cross-sectional areas of all cooling tubes (2) of a supercooling parallel portion (14, 16, 18) is less than the product of 0.9 or 0.7 or 0.5 or 0.3 or 0.1 and the sum total of the flow cross-sectional areas of all cooling tubes (2) of a parallel portion (19, 21, 23), and/or the cooling tubes (2) are formed as flat tubes (3) and corrugated fins (4) are arranged between the flat tubes.
8. The refrigerant condenser assembly (1) for a motor vehicle air-conditioning system as claimed in one of the preceding claims, comprising

   - corrugated fins which are arranged between the cooling tubes,

   characterised in that
   the geometry of the corrugated fins of the supercooling region (13) differs from the geometry of the corrugated fins of the superheat region (11) and/or the condensation region (12).
9. A motor vehicle air-conditioning system, comprising

   - a refrigerant condenser assembly (1),

   - an evaporator,

   - a compressor,

   - preferably a fan,

   - preferably a housing for accommodating the fan and the evaporator,

   characterised in that
   the refrigerant condenser assembly (1) is designed as claimed in one or more of claims 1 to 8.

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