DE102019114100A1 - Inner heat exchanger - Google Patents

Abstract

The invention relates to an internal heat exchanger (1) of a refrigerant circuit (2), which is provided for heat exchange between refrigerant from a high pressure area (3) of the refrigerant circuit (2) and refrigerant from a low pressure area (4) of the refrigerant circuit (2), with a High-pressure pipe (5) with a first refrigerant inlet (6) and a first refrigerant outlet (7), the high-pressure pipe (5) being shaped into a high-pressure helix (8) which is arranged between an inner cylinder wall (9) and an outer cylinder wall (10) is for the flow of the refrigerant in the high pressure area (3), the space (11) between the turns (12) of the high pressure coil (8) between the inner cylinder wall (9) and the outer cylinder wall (10) as a low pressure coil (13) for the flow through the Refrigerant in the low-pressure region (4) is used, the high-pressure pipe (5) having an outer diameter D and a slope S, the cross-sectional area of the never The pressure coil (13) of one revolution of the low-pressure coil (13) A is: A = S * D − π / 4 * D2, where A is in the range from 30 to 60 mm2 and D is in the range from 6 to 9 mm.

Description

Technical area

The invention relates to an internal heat exchanger, in particular for a refrigerant circuit of an air conditioning system of a motor vehicle.

Background of the invention

In the case of air conditioning systems for motor vehicles, it is known that an internal heat exchanger is used which carries out a heat exchange between the refrigerant from the high-pressure area and the refrigerant from the low-pressure area. A high-pressure tube is typically formed into a high-pressure coil, which is arranged between an inner cylinder wall and an outer cylinder wall, for the flow of the refrigerant in the high-pressure area, the space between the turns of the high-pressure coil between the inner cylinder wall and the outer cylinder wall is used as a low-pressure coil Flow of refrigerant in the low pressure range.

The thermodynamic performance of the inner heat exchanger depends crucially on the flow cross-section of the low-pressure coil between the high-pressure coil and the inner cylinder wall and the outer cylinder wall, with manufacturing tolerances playing a decisive role. However, the diameter of the tube of the high pressure coil, the pitch and the number of turns of the high pressure coil determine the pressure loss on the low pressure side in the low pressure coil.

Presentation of the invention, task, solution, advantages

It is the object of the invention to create an internal heat exchanger which is improved over the prior art with regard to the pressure drop in the low pressure range.

The object is achieved with the features of claim 1.

wobei A im Bereich von 30 bis 60 mm² und D im Bereich von 6 bis 9 mm liegt. Dadurch wird erreicht, dass der Druckabfall im Niederdruckbereich einen akzeptablen Wert annimmt.One embodiment of the invention relates to an internal heat exchanger of a refrigerant circuit, which is provided for a heat exchange between refrigerant from a high pressure area of the refrigerant circuit and refrigerant from a low pressure area of the refrigerant circuit, with a high pressure pipe with a first refrigerant inlet and a first refrigerant outlet, the high pressure pipe leading to a high pressure coil is formed, which is arranged between an inner cylinder wall and an outer cylinder wall for the flow of refrigerant in the high pressure area, the space between the windings of the high pressure coil between the inner cylinder wall and the outer cylinder wall serves as a low pressure coil for the flow of refrigerant in the low pressure area, the high pressure pipe has an outer diameter D and a pitch S, the cross-sectional area of the low-pressure helix of one revolution of the low-pressure helix A being: $$\text{A.}=\text{S * D}-\mathrm{\pi }{\text{/ 4 * <figure-callout id="2" label="D" filenames="DE102019114100A1\_0005.png,DE102019114100A1\_0006.png" state="{{state}}">D</figure-callout>}}^{\text{2}}$$

where A is in the range from 30 to 60 mm ² and D is in the range from 6 to 9 mm. This ensures that the pressure drop in the low-pressure range assumes an acceptable value.

In particular, the optimum of A lies at a diameter D _optA of 2 * S / π.

It is particularly advantageous if A is in the range from 35 to 55 mm ² and / or D is in the range from 6 to 8.5 mm.

In another exemplary embodiment, it is also advantageous if S / D is in the range between 0.7 and 3, in particular between 1 and 2.

Furthermore, it is also advantageous if the ratio between the pitch S and the outer diameter D, that is S / D, is in the range between 1.4 and 1.6, in particular 1.57. This creates a favorable cross-sectional area for the low-pressure coil.

It is particularly advantageous if the high-pressure pipe has a wall thickness d which is in the range of 0.3 and 1.5 mm. In this way, on the one hand, a stable tube design is selected and, on the other hand, a sufficiently large free cross-sectional area for the refrigerant to flow through is achieved.

It is particularly advantageous if the inner cylinder wall is an outer wall of an accumulator container for refrigerant. This achieves an integrated design.

It is also advantageous if the outer cylinder wall is a housing wall of a surrounding housing. As a result, an integrated design is also achieved, with no separate tube being required for the low-pressure coil.

It is also advantageous if the outer cylinder wall is closed on both sides by a cover. This creates a closed vessel that houses the two coils, the high pressure coil and the low pressure coil.

It is also advantageous if first connection elements are arranged in the covers, by means of which the high pressure tube can be connected to the refrigerant circuit as a high pressure coil.

It is also advantageous if second connection elements are arranged in the covers, by means of which the low-pressure coil can be connected to the refrigerant circuit.

Further advantageous embodiments are described by the following description of the figures and by the subclaims.

Figure list

• 1 eine schematische Darstellung eines inneren Wärmeübertragers,
• 2 eine Ansicht einer Teilwendel der Hochdruckwendel des inneren Wärmeübertragers, und
• 3 ein Diagramm zur Erläuterung der Erfindung.

The invention is explained in more detail below on the basis of several exemplary embodiments with reference to the figures of the drawings. Show it:

• 1 a schematic representation of an internal heat exchanger,
• 2 a view of a partial coil of the high pressure coil of the internal heat exchanger, and
• 3 a diagram to explain the invention.

Preferred embodiment of the invention

The 1 shows a schematic representation of a partial section through an embodiment of an internal heat exchanger 1 as it is, for example, in a refrigerant circuit 2 , in particular a motor vehicle can be used.

The internal heat exchanger 1 is for heat exchange between refrigerants from a high pressure area 3 of the refrigerant circuit 2 and refrigerant from a low pressure range 4th of the refrigerant circuit 2 intended. The internal heat exchanger 1 has a high pressure pipe 5 with a first refrigerant inlet 6th and a first refrigerant outlet 7th on, with the high pressure pipe 5 to a high pressure coil 8th is shaped.

The high pressure coil 8th is between an inner cylinder wall 9 and an outer cylinder wall 10 arranged. It is used to flow through the refrigerant in the high pressure area 3 . The 2 shows a section of the high pressure coil 8th of the high pressure pipe 5 between the inner cylinder wall 9 and the outer cylinder wall 10 . Through the high pressure pipe 5 the refrigerant flows in the high pressure area 3 .

The gap 11 between the turns 12 the high pressure coil 8th between the inner cylinder wall 9 and the outer cylinder wall 10 serves as a low pressure coil 13 for the flow of the refrigerant in the low pressure range 4th .

The high pressure pipe 5 an outer diameter D and a pitch S, the cross-sectional area A of the low-pressure coil 13 one revolution of the low pressure coil 13 the following value is: $$\text{A.}=\text{S * D}-\mathrm{\pi }{\text{/ 4 * <figure-callout id="2" label="D" filenames="DE102019114100A1\_0005.png,DE102019114100A1\_0006.png" state="{{state}}">D</figure-callout>}}^{\text{2}}.$$

According to the invention, the value of A is in the range from 30 to 60 mm ² . A is advantageously in the range from 35 to 55 mm ² .

According to the invention, the value of D is in particular in the range from 6 to 9 mm, in particular in the range from 6 to 8.5 mm.

The ratio of the slope S to the outer diameter D, that is S / D, is in the range between 0.7 and 3, in particular between 1 and 2, advantageously in the range between 1.4 and 1.6, in particular 1.57.

The high pressure pipe 5 has a wall thickness d which is in the range of 0.3 and 1.5 mm.

The 1 shows that the inner cylinder wall 9 an outer wall of a battery container 14th for refrigerant is. The outer cylinder wall 10 is a housing wall of a surrounding housing 15th .

Here is the case 15th and thus the outer cylinder wall 10 on both sides of a cover 16 locked. In the two lids 16 are the first connection elements 17th arranged, by means of which the high pressure pipe 5 as a high pressure helix 8th to the refrigerant circuit 2 is connectable. Furthermore are in the lids 16 second connection elements 18th arranged, by means of which the low pressure coil 13 to the refrigerant circuit 2 is connectable.

The 3 shows a diagram in which curves 20th to 24 are shown, which is the area A of the low pressure coil 13 (ND) are plotted as a function of the diameter D at various slopes S from 11.4 mm to 13.0 mm. The curve 25th shows the course of the maximum of the curves 20th to 24 as a function of D. It can be seen that the maximum of the area A shifts towards a larger slope S towards a larger D and lies in the range from about 6.5 to 8.5.

Claims (10)

Inner heat exchanger (1) of a refrigerant circuit (2), which is used for heat exchange between refrigerants from a high-pressure area (3) of the refrigerant circuit (2) and refrigerant from a low-pressure region (4) of the refrigerant circuit (2) is provided, with a high-pressure pipe (5) with a first refrigerant inlet (6) and a first refrigerant outlet (7), the high-pressure pipe (5) becoming a High-pressure coil (8) is formed, which is arranged between an inner cylinder wall (9) and an outer cylinder wall (10) for the flow of the refrigerant in the high-pressure area (3), the space (11) between the turns (12) of the high-pressure coil (8 ) is used between the inner cylinder wall (9) and the outer cylinder wall (10) as a low-pressure helix (13) for the flow of the refrigerant in the low-pressure region (4), characterized in that the high-pressure pipe (5) has an outer diameter D and a pitch S, wherein the cross-sectional area of the low-pressure helix (13) one revolution of the low-pressure helix (13) A is: $$\text{A.}=\text{S * D}-\mathrm{\pi }{\text{/ 4 * D}}^{\text{2}}$$

where A is in the range from 30 to 60 mm ² and D is in the range from 6 to 9 mm. Inner heat exchanger (1) after Claim 1 , characterized in that A is in the range of 35 to 55 mm ² and / or D is in the range of 6 and 8.5 mm. Inner heat exchanger (1) after Claim 1 or 2 , characterized in that S / D is in the range between 0.7 and 3, in particular between 1 and 2. Inner heat exchanger (1) after Claim 3 , characterized in that S / D is in the range between 1.4 and 1.6, in particular 1.57. Inner heat exchanger (1) according to one of the preceding claims, characterized in that the high-pressure pipe (5) has a wall thickness d which is in the range of 0.3 and 1.5 mm. Inner heat exchanger (1) according to one of the preceding claims, characterized in that the inner cylinder wall (9) is an outer wall of an accumulator container (14) for refrigerant. Inner heat exchanger (1) according to one of the preceding claims, characterized in that the outer cylinder wall (10) is a housing wall of a surrounding housing (15). Inner heat exchanger (1) according to one of the preceding claims, characterized in that the outer cylinder wall (10) is closed on both sides by a cover (16). Inner heat exchanger (1) after Claim 8 , characterized in that first connection elements (17) are arranged in the covers (16), by means of which the high-pressure pipe (5) can be connected to the refrigerant circuit (2) as a high-pressure helix (8). Inner heat exchanger (1) according to one of the preceding claims, characterized in that second connection elements (18) are arranged in the covers (16), by means of which the low-pressure coil (13) can be connected to the refrigerant circuit (2).

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