EP2926073B1 - Heat exchanger - Google Patents

Description

Technical area

The invention relates to a heat exchanger with a first flow channel for a refrigerant, with a second flow channel for a refrigerant and with a third flow channel for a coolant, wherein the first flow channel a first region for first cooling of the refrigerant and a second region for further cooling of the refrigerant wherein, in the first flow channel, the refrigerant can be flowed in a high-pressure phase and in the second flow channel, the refrigerant can be flowed in a low-pressure phase. A heat exchanger with the features of the preamble of claim 1 is made FR 2 924 490 known.

State of the art

In automotive vehicle air conditioning refrigerant circuits, condensers are used to cool a refrigerant to the condensation temperature and then condense the refrigerant. This occurs in particular with refrigerants which experience at least one phase transition from gaseous to liquid within the refrigerant circuit. Regularly, capacitors have a collector, in which a volume of refrigerant can be kept in order to compensate for volume fluctuations in the refrigerant circuit. As a result, a stable supercooling of the refrigerant can be achieved.

Often, additional means for drying and / or filtering the refrigerant are provided in the collector. The collector is usually arranged on the capacitor. It is flowed through by the refrigerant, which has already flowed through part of the condenser. After flowing through the collector, the refrigerant is returned to the condenser and subcooled in a subcooling below the condensation temperature.

Also, capacitors are known in which the refrigerant undergoes no phase transition. These capacitors regularly have only one cooling section, in which the refrigerant is brought into thermal contact with a coolant.

Furthermore, heat exchangers are known, which after the condensation section and the subcooling an internal heat exchanger is connected downstream. A collector is preferably arranged between the condensation section and the subcooling section. While heat transfer takes place between a refrigerant and a coolant within the condensation section and the subcooling section, a heat transfer takes place in the internal heat exchanger between the refrigerant in two different states, namely in a high pressure phase and a low pressure phase.

A disadvantage of the devices known from the prior art is in particular that when using CO ₂ (R744) as refrigerant high pressures within the refrigerant circuit occur, which burden the previously known heat exchanger beyond their load limits.

Presentation of the invention, object, solution, advantages

It is therefore the object of the present invention to provide a heat exchanger which can be subjected to high pressures, as occur, for example, when CO ₂ (R 744) is used. In addition, the heat exchanger should characterized by a compact design and cost-effective production.

The object of the present invention is achieved by a heat exchanger with the features of claim 1.

An embodiment of the invention relates to a heat exchanger with a first flow channel for a refrigerant, with a second flow channel for a refrigerant and with a third flow channel for a coolant, wherein the first flow channel has a first region for first cooling of the refrigerant and a second region for further cooling of the refrigerant, wherein in the first flow channel, the refrigerant is flowable in a high pressure phase and in the second flow channel, the refrigerant is flowable in a low pressure phase, wherein a first heat transfer between the refrigerant in the first region of the first flow channel and the coolant takes place in the third flow channel and a second Heat transfer between the refrigerant takes place in the second region of the first flow channel and the refrigerant in the second flow channel.

By an additional heat transfer between the refrigerant in its high pressure phase and the refrigerant in its low pressure phase, the temperature of the refrigerant can be further lowered in the high pressure phase. As a result, the cooling capacity in the refrigerant circuit can be increased overall.

In a further embodiment of the invention, it may be provided that the second region of the first flow channel and the second flow channel form a first unit and the first region of the first flow channel and the third flow channel form a second unit, wherein the first unit and the second unit can be connected as a unit.

According to the invention, the heat exchanger has an accumulator which stores a storage volume of the refrigerant and / or means for filtering and / or means for drying the refrigerant.

The accumulator serves as a storage medium for the refrigerant. Advantageously, it stores the refrigerant in the low pressure phase between. This is used to compensate for volume fluctuations of the refrigerant or to compensate for refrigerant losses, which may arise for example due to leaks. In addition, the accumulator may advantageously comprise means for drying and / or filtering the refrigerant. This has an advantageous effect on the quality of the refrigerant and thus also on the efficiency of the refrigerant circuit.

It may also be advantageous if the accumulator is assigned to the heat exchanger.

By assigning the additional accumulator to the heat exchanger may be particularly advantageous if the heat exchanger itself must be made as compact as possible. The accumulator can be installed independently of the heat exchanger in the vehicle.

According to the invention, the passage of refrigerant out of the second region of the first flow channel leads into the second flow channel via the accumulator.

By the refrigerant passing through the accumulator can be ensured that volume fluctuations of the refrigerant can be fully compensated at any time. Overall, it improves the efficiency of the refrigerant circuit.

Furthermore, it may be expedient if the third flow channel is adjacent to the first region of the first flow channel and the second flow channel is adjacent to the second region of the first flow channel.

By arranging the flow channels in this way, the heat transfer between the refrigerant in the first region of the first flow channel and the coolant in the third flow channel and also the heat transfer between the refrigerant in the second region of the first flow channel and the refrigerant in the second flow channel is favored.

In addition, it may be advantageous if the first unit and / or the second unit is formed in stacked disc design.

A construction in stacking disk design is particularly simple and particularly cost-effective due to the small number of different elements.

It is also preferable if the first unit and / or the second unit is formed in tube-rib construction.

In a further embodiment of the invention, it may be provided that the first unit and / or the second unit is formed by a plurality of tubes, wherein the tubes are adjacent to each other and at least partially in thermal contact with each other, wherein the tubes of each the refrigerant and / or the coolant can flow through.

The flow of the refrigerant and the coolant in pipes is particularly advantageous, in particular with regard to the pressure resistance of the heat exchanger. By using pipes, a particularly high compressive strength can be achieved.

Furthermore, it may be advantageous if the first unit and / or the second unit is formed by a plurality of tubes, wherein between the tubes turbulence inserts are arranged, wherein the arrangement of tubes and turbulence inserts is encased by a housing, wherein the tubes of a Coolant and / or a refrigerant can flow through and can be flowed around by a coolant and / or a refrigerant.

A structure in which a part of the tubes is flowed through by a first fluid and at the same time flows around a second fluid is particularly advantageous, since in this way a particularly high heat transfer can be realized.

In particular, by a mixed construction of a unit which is formed in stacked disk construction and a unit which is formed in tube-rib construction, the advantages of both designs can be combined.

A preferred embodiment of the invention is characterized in that the heat exchanger is formed in a stacked disk construction, wherein the stacking of individual disc elements, a heat exchanger block is formed and formed between the disc elements channels, wherein a first number of channels is associated with the first flow channel, a second number the channels is associated with the second flow channel and a third number of the channels is associated with the third flow channel.

The construction in a Stapelscheibenbauwese is particularly advantageous because a large number of identical parts can be used. Depending on the design of the heat exchanger, only the two respective outer disk elements must deviate from the others. As a result, the costs and the production costs can be significantly reduced.

In addition, it may be advantageous if one or more of the flow channels experience one or more deflections of their flow direction, as a result of which the fluid flows in the flow channels can run in cocurrent and / or countercurrent and / or crosstalk.

By deflections in the interior of the heat exchanger, the fluid flows can be advantageously controlled. As a result, the heat transfer can be significantly increased and the efficiency of the refrigerant circuit can be improved.

According to the Invention, the accumulator has the second region of the first flow channel and the second flow channel, wherein heat transfer takes place within the accumulator between the second region of the first flow channel and the second flow channel.

Such a design is advantageous because the heat exchanger can be made even more compact, which is particularly advantageous in terms of the available space.

A further preferred embodiment is characterized in that the accumulator and the heat exchanger are designed as a structural unit.

An assembly of the accumulator and the heat exchanger is advantageous because the required space can be reduced overall. In addition, a simpler installation in the vehicle is possible because no additional piping between the heat exchanger and the accumulator must be provided.

Furthermore, it is advantageous if the refrigerant is CO ₂ (R744).

It may also be expedient if the heat exchanger has a compressive strength that allows internal pressures greater than 100 bar.

In particular, when using CO ₂ (R744) as a refrigerant, it is advantageous if the heat exchanger can withstand high internal pressures. When operating with CO ₂ (R744) as a refrigerant, pressures of 100 bar and more can occur.

The compressive strength of 100 bar and more is particularly advantageous for the areas through which the high-pressure refrigerant flows. Also for the areas through which the low-pressure refrigerant and the coolant flow, this pressure resistance may be advantageous.

Advantageous developments of the present invention are described in the subclaims and the following description of the figures.

Brief description of the drawings

Fig.1

eine perspektivische Ansicht eines Wärmeübertragers mit einer inneren Abkühlstrecke und einem inneren Wärmeübertrager,

Fig. 2

eine perspektivische Ansicht eines Wärmeübertragers gemäß Figur 1 und einen zusätzlichen Akkumulator,

Fig. 3

eine Schnittansicht durch einen Wärmeübertrager mit einer Mehrzahl von Strömungskanälen für ein Niederdruckkältemittel, ein Hochdruckkältemittel und ein Kühlmittel, und

Fig. 4

eine perspektivische Ansicht eines Wärmeübertragers mit einer Abkühlstrecke und einen Akkumulator, in den ein innerer Wärmeübertrager integriert ist.

In the following the invention will be explained in detail by means of embodiments with reference to the drawings. In the drawings show:

Fig.1

a perspective view of a heat exchanger with an inner cooling path and an internal heat exchanger,

Fig. 2

a perspective view of a heat exchanger according to FIG. 1 and an additional accumulator,

Fig. 3

a sectional view through a heat exchanger having a plurality of flow channels for a low-pressure refrigerant, a high-pressure refrigerant and a coolant, and

Fig. 4

a perspective view of a heat exchanger with a cooling line and an accumulator, in which an internal heat exchanger is integrated.

Preferred embodiment of the invention

The Fig. 1 shows a schematic view of a heat exchanger 1. The heat exchanger 1 is divided into a cooling section 6 and in an inner heat exchanger 5. Within the cooling section 6, a refrigerant in a high-pressure phase (high-pressure refrigerant) 2 is brought into thermal contact with a coolant 3, so that a heat transfer from the high-pressure refrigerant 2 to the coolant 3 is formed. In the internal heat exchanger 5, the high-pressure refrigerant 2 with the same refrigerant, but in a low-pressure phase (low-pressure refrigerant) 4 in thermal Brought in contact. In the inner heat exchanger 5, the Hochdrucckältemittel 2 is thus further cooled.

The high-pressure refrigerant 2 flows via a fluid inlet 7 into the cooling section 6. Inside the cooling section 6, a plurality of flow channels are arranged, which are partially flowed through by the high-pressure refrigerant 2 and through which the coolant 3 flows. Within the internal heat exchanger 5 also a plurality of flow channels are arranged, wherein a number of these flow channels is associated with the low-pressure refrigerant 4 and a further number of channels is associated with the high-pressure refrigerant 2. Both the flow channels in the internal heat exchanger 5 and in the cooling section 6 are not shown for reasons of clarity.

The flow channels for the high-pressure refrigerant 2, the coolant 3 and the low-pressure refrigerant 4 may be arranged within the heat exchanger in any order. In this case, the flow channels of the different fluids can be arranged, for example, alternately. Alternatively, an arrangement may be provided in which a plurality of flow channels for the same fluid are arranged adjacent to each other.

The flow of the high-pressure refrigerant 2 through the heat exchanger 1 runs along the fluid inlet 7 through the flow channels in the interior of the cooling section 6 along the flow channels in the inner heat exchanger 5 and finally out of the heat exchanger 1 from the fluid outlet 8. The coolant 3 flows via the fluid inlet 9 into the cooling section 6 of the heat exchanger 1 and there along the flow channels within the cooling section 6 to the fluid outlet 10. There, it flows out of the heat exchanger 1 from.

The low-pressure refrigerant 4 flows via a fluid inlet 11 into the inner heat exchanger 5 and there along the flow channels associated therewith through the inner heat exchanger 5. It finally flows out of the inner heat exchanger 5 via the fluid outlet 12.

In the interior of the heat exchanger 1 deflections may be provided, whereby the flow direction of the individual fluids is deflected. In this case, areas can be generated in which two fluids flow in cocurrent or in countercurrent to each other. By a clever arrangement of the flow channels and deflections in the interior of the heat exchanger 1 is also achievable that two fluids flow in a cross flow to each other.

The high-pressure refrigerant 2 is within the refrigerant circuit, softer in the Fig. 1 is not shown, transferred via a likewise not shown expansion valve in a low pressure phase and thus to the low pressure refrigerant 4.

The Fig. 2 shows a further schematic view of the heat exchanger 1, as already in Fig. 1 was shown. The with the Fig. 1 identical features of the heat exchanger 1 are denoted by identical reference numerals.

Additionally is in Fig. 2 an accumulator 13 is shown. This accumulator 13 serves to store the low-pressure refrigerant 4, which flows into the accumulator 13 via a fluid inlet 14 and flows out of the accumulator 13 via a fluid outlet 15. In addition, the accumulator 13 may include means for filtering, cleaning and drying the low-pressure refrigerant 4. Via a storage volume in the interior of the accumulator 13, a fluctuation of the refrigerant volume within the refrigerant circuit can be compensated. This ensures a stable cooling of the refrigerant 2, 4 within the refrigerant circuit. Likewise, leaks within the refrigerant circuit can be at least partially compensated.

The accumulator 13 is arranged immediately in front of the fluid inlet 11 of the heat exchanger 1. The low-pressure refrigerant 4 thus flows directly from the accumulator 13 into the internal heat exchanger 5 of the heat exchanger 1.

The accumulator 13 can as in Fig. 2 be shown as a separate component, which is arranged in the vicinity of the heat exchanger 1. In alternative embodiments, an integration of the accumulator in the heat exchanger is providable. The design of the heat exchanger and the accumulator in a unit is particularly advantageous in terms of the required installation space of the unit.

The Fig. 3 shows a sectional view through a heat exchanger. The arrangement of the various flow channels 23, 24, 25 is shown. The high-pressure refrigerant 20 is assigned the first flow channel 23, which divides into a first region 23a and a second region 23b. At the first region 23 a of the first flow channel 23, the high-pressure refrigerant 20 comes into thermal contact with a coolant 21, whereby a heat transfer between the high-pressure refrigerant 20 and the coolant 21 is formed. At the second region 23b of the first flow channel 23, the heat transfer between the high-pressure refrigerant 20 and the low-pressure refrigerant 22 takes place.

In order to represent a heat transfer between the first region 23a of the first flow channel 23 and the high-pressure refrigerant 20 and the coolant 21 flowing therein, the flow channel 23 is in thermal contact with another flow channel 24. The flow channel 24 in this case has a plurality of rib elements 26, which serve to increase the heat transfer surface.

This in Fig. 3 shown example of the arrangement of the flow channels within a heat exchanger provides that the heat transfer between the high-pressure refrigerant 20 and the coolant 21 via flow channels in pipe rib design. In this case, the first region 23a of the flow channels 23 flows through the refrigerant, wherein the flow channels 24 are arranged between the flow channels 23 and by a coolant, such as the ambient air or cooling water, flows through. As a result, the first region 23a flows around the coolant 21.

The first regions 23a of the flow channels 23 are substantially bypassed by the coolant 21 while flowing through the high-pressure refrigerant 20. The operation of the cooling section 27 corresponds to the ordinary pipe-fin type heat exchanger in which a fluid flows through a first number of pipes while a second fluid flows around this number of pipes.

In the Fig. 3 shown arrangement can be covered by a housing. The housing can be flowed through by the coolant whereby the tubes through which the refrigerant flows, are flowed around.

The heat transfer between the high-pressure refrigerant 20 and the low-pressure refrigerant 22 takes place between the second region 23b of the flow channels 23 of the high-pressure refrigerant 20 and the flow channels 25 of the low-pressure refrigerant 22. The area of Fig. 3 , which is formed by the flow channels 24 and the first region 23 of the first flow channels 23, corresponds to the Abkühlstrecke 27. The range of Fig. 3 , which is formed by the second region 23b of the first flow channels 23 and the flow channels 25, corresponds to the internal heat exchanger 28.

In alternative embodiments, the cooling section 27 can be represented by flow channels brought together in thermally conductive contact. It is also conceivable to use a liquid coolant.

The first unit of the heat exchanger, which is formed by the second region 23b of the first flow channel 23 and the second flow channel 25 and the second unit of the heat exchanger, which is formed from the first region 23a of the first flow channel 23 and the third flow channel 24 can optionally by a construction in stacking disk construction, in pipe-fin construction or by a juxtaposition of pipes, which are flowed through by the refrigerant or the coolant to be formed.

Alternatively, an arrangement of tubes, between which turbulence liners are arranged, providable, wherein the tubes and turbulence inserts are then flowed around by either the refrigerant or the coolant. In this case, a housing is advantageously provided, which surrounds the arrangement of tubes and turbulence inserts.

The Fig. 4 shows an alternative embodiment of the heat exchanger 30. The heat exchanger 30 now consists only of a cooling section, in which the high-pressure refrigerant 39 is brought into thermal contact with the coolant 40. The structure of the heat exchanger 30 corresponds essentially to the cooling section 6 of the heat exchanger 1 of Fig. 1 ,

Similar to in Fig. 2 is in Fig. 4 an additional accumulator 31 is arranged. Through this, a low-pressure refrigerant 41 flows in via the fluid inlet 32 and out of the accumulator 31 out of the fluid outlet 33. In addition, the high-pressure refrigerant 39, which has flowed out of the fluid outlet 36 of the heat exchanger 30, flows into the accumulator 31.

For this purpose, the accumulator 31 has in particular the second region 34 of the first flow channel, which is brought into thermally conductive contact with the low-pressure refrigerant 41. For this purpose, the accumulator 31 may have in its interior a plurality of flow channels.

As well as in Fig. 2 already described, the accumulator 31 of the Fig. 4 be designed as a separate component as shown. In alternative embodiments, it may also be integrated directly into the heat exchanger 30.

In particular, the positioning of the fluid inlets and the fluid outlets represents only one possibility of the arrangement. The fluid inlets and fluid outlets can be arbitrarily arranged on the heat exchanger and the accumulator. Advantageous solutions result in particular by the choice of the internal structure of the Heat exchanger. Thus, in an embodiment in stacked disc design, the fluid inlets and the fluid outlets are advantageously arranged on the two outer disc elements closing off the stack.

In all Fig. 1 to 4 the refrigerant circuit surrounding each heat exchanger is not shown. The embodiments of the Fig. 1 to 4 are merely exemplary in nature and are not an exhaustive list and representation of the embodiments. They are not of a restrictive nature.

Claims (10)

1. A heat exchanger (1, 30) with a first flow channel (23) for a refrigerant (2, 20, 39), a second flow channel (25) for a refrigerant (4, 22, 41), and a third flow channel (24) for a coolant (3, 21, 40), wherein the first flow channel (23) has a first region (23a) for the initial cooling of the refrigerant (2, 20, 39) and a second region (23b) for the further cooling of the refrigerant (2, 20, 39), wherein the refrigerant (2, 20, 39) can flow in a high-pressure phase in the first flow channel (23) and the refrigerant (4, 22, 41) can flow in a low-pressure phase in the second flow channel (25), wherein a first heat transfer occurs between the refrigerant in the first region (23a) of the first flow channel (23) and the coolant in the third flow channel (24) and a second heat transfer occurs between the refrigerant in the second region (23b) of the first flow channel (23) and the refrigerant in the second flow channel (25), wherein the heat exchanger (1, 30) has an accumulator (13, 31) which has a storage volume for storing the refrigerant (4, 22, 41) and/or means for filtering and/or means for drying the refrigerant (4, 22, 41), wherein the refrigerant transfer from the second region (23b) of the first flow channel (23) to the second flow channel (25) passes through the accumulator (13, 31), and characterised in that the accumulator (31) has the second region (23b, 34) of the first flow channel (23) and the second flow channel (25), wherein a heat transfer occurs between the second region (23b, 34) of the first flow channel (23) and the second flow channel (25) within the accumulator (31).
2. The heat exchanger (1, 30) according to claim 1, characterised in that the second region (23b) of the first flow channel (23) and the second flow channel (25) form a first unit and the first region (23a) of the first flow channel (23) and the third flow channel (24) form a second unit, wherein the first unit and the second unit can be connected as a structural unit.
3. The heat exchanger (1, 30) according to claim 1 or 2, characterised in that the third flow channel (24) is adjacent to the first region (23a) of the first flow channel (23) and the second flow channel (25) is adjacent to the second region (23b) of the first flow channel (23).
4. The heat exchanger (1, 30) according to one of claims 1 to 3, characterised in that the first unit and/or the second unit are formed with a stacked plate design.
5. The heat exchanger (1, 30) according to one of claims 1 to 4, characterised in that the first unit and/or the second unit are formed with a tube-fin design.
6. The heat exchanger (1, 30) according to one of claims 1 to 5, characterised in that the first unit and/or the second unit are formed by a plurality of tubes, wherein the tubes are arranged adjacent to one another and are at least partially in thermal contact with one another, wherein the refrigerant (2, 4, 20, 22, 39, 41) and/or the coolant (3, 21, 40) can flow through the tubes.
7. The heat exchanger (1, 30) according to one of claims 1 to 6, characterised in that the first unit and/or the second unit are formed by a plurality of tubes, wherein turbulence inserts (26) are arranged between the tubes, wherein the arrangement of tubes and turbulence inserts (26) is encased by a housing, wherein a coolant (3, 21, 40) and/or a refrigerant (2, 4, 20, 22, 39, 41) can flow through the tubes and a coolant (3, 21, 40) and/or a refrigerant (2, 4, 20, 22, 39, 41) can flow around them.
8. The heat exchanger (1, 30) according to one of the preceding claims, characterised in that one or more of the flow channels (23, 24, 25) experience one or more redirections in their flow direction, as a result of which the fluid flows in the flow channels (23, 24, 25) can run in a co-current flow and/or in a counter-flow and/or in a cross-flow to one another.
9. The heat exchanger (1, 30) according to one of the preceding claims, characterised in that the accumulator (13, 31) and the heat exchanger (1, 30) are made as a structural unit.
10. Use of the heat exchanger according to one of the preceding claims, wherein CO₂ (R744) is used as the refrigerant.

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