Heat exchanger

Abstract

Title: Heat Exchanger The invention relates to a heat exchanger (1), in particular of the internal heat exchanger type, also called IHX, comprising: - a plurality of first-type plates (10) provided with corrugations (12), - a plurality of second-type plates (20) provided with corrugations (22), the first-type plates (10) and second-type plates (20) being arranged alternately, the first-type plates (10) and second-type plates (20) being joined together by a plurality of contact plates (14, 16, 24, 26), - the corrugations (12, 22) defining, between consecutive plates, channels (42, 44) allowing the passage of fluid, these channels (42, 44) being distributed between channels (42) of the first fluid passage section and channels (44) of the second fluid passage section, - the first fluid passage section being smaller than the second section fluid passage of the channels (44). Figure for the abbreviation: Fig. 4

Description

Title of the invention: Heat exchanger

[0001] The field of the present invention relates to heat exchangers.

[0002] In an air conditioning loop, it is known to use an internal heat exchanger (IHX). This is used to ensure that the refrigerant is completely evaporated at the compressor inlet and also to increase evaporation capacity by increasing subcooling. This type of internal heat exchanger operates with a low-pressure side (also called the LP side) and a high-pressure side (also called the HP side).

[0003] Generally, a low pressure drop is required on the low-pressure side, namely the side where the fluid is in the vapor phase. To achieve this, a large flow area is needed to reduce the pressure drop.

[0004] During operation, pressures of 27 or 28 bar can be reached for certain refrigerants. For a refrigerant such as propane, even higher pressures are required, particularly above 30 bar. This necessitates a substantial increase in the burst pressure resistance of these heat exchangers.

[0005] Heat exchangers that meet this burst pressure constraint are, for example, plate exchangers with crossed chevrons and "Dimples" which allow brazing points that are regular.

[0006] The invention proposes in particular to further improve heat exchangers which include two fluid circuits.

[0007] The invention thus relates to an internal heat exchanger, also called an IHX, comprising: - a plurality of first-type plates equipped with corrugations, - a plurality of second-type plates equipped with corrugations, the plates of the first type and plates of the second type being arranged alternately in a stack of plates, the plates of the first type and plates of the second type being joined together, preferably brazed together, by a plurality of contact plates at the junction between two consecutive plates of the stack, - the corrugations of the plates, generally elongated in shape, defining channels between consecutive plates that allow fluid to pass between a fluid inlet zone and a fluid outlet zone. These channels are distributed between first-section fluid passage channels and second-section fluid passage channels, the first-section passage channels of the heat exchanger, and the channels of the second section of the heat exchanger being alternated on either side of the stack plates, the channels of the first section of the heat exchanger being configured to form a first fluid circuit for a first heat transfer fluid and the channels of the second section of the heat exchanger being configured to form a second fluid circuit for a second heat transfer fluid, - the first fluid passage section, especially on the HP side, of the channels being smaller than the second fluid passage section, especially on the LP side, of the channels.

[0008] According to an example of the invention, the first fluid passage section corresponds to the high pressure (HP) side of an internal heat exchanger (IHX) and the second fluid passage section corresponds to the low pressure (LP) side of the internal heat exchanger (IHX).

[0009] According to the present invention, the first heat transfer fluid and the second heat transfer fluid can be the same heat transfer fluid from the same fluid circuit but at different pressures / states (liquid / gaseous), or be different heat transfer fluids belonging to two separate fluid circuits.

[0010] In the case where the first type plates and the second type plates are brazed, the contact surfaces are brazing surfaces. Instead of being brazed together, the plates can, in alternative configurations, be welded or bonded together.

[0011] Thanks to the invention, due to the difference between the first fluid passage section and the second fluid passage section, an asymmetry is obtained in the plates in order to obtain a reduction in fluid volume in one of the fluid circuits compared to the other fluid circuit.

[0012] This difference between the fluid volumes also makes it possible to adjust the pressure losses between the first fluid circuit and the second fluid circuit, in particular to reduce the pressure losses on the low pressure (LP) side by increasing the pressure losses on the high pressure (HP) side.

[0013] The fact that the first section passage channels of the heat exchanger and the second section passage channels of the heat exchanger are alternated on either side of the stacking plates means that the first section passage channels are formed by assembling a first type plate with a second type plate according to a predetermined stacking direction of the plates, and the second section passage channels are formed by assembling a second type plate with a first type plate according to said predetermined stacking direction of the plates.

[0014] For example, in the case of an IHX type heat exchanger (which has a high-pressure (HP) circuit and a low-pressure (LP) circuit), we obtain thanks The invention involves a reduction in fluid volume on the high-pressure (HP) side and an increase in volume on the low-pressure (LP) side. On the high-pressure side, the refrigerant is in the liquid phase, resulting in a high fluid density and therefore a low fluid velocity. On the low-pressure side, the refrigerant is in the gaseous phase. To achieve the same flow rate in the gaseous phase, a much higher velocity is required. This velocity creates a pressure drop. Thanks to the invention, this pressure drop is reduced (by increasing the volume on the low-pressure side).

[0015] In the case of an IHX type heat exchanger, advantageously, the heat exchanger is configured so that the fluid volume distribution ratio between the first fluid circuit and the second fluid circuit is between 1.5 and 3.

[0016] For example, we can have 1.5 times more fluid on the low pressure (LP) side than on the high pressure (HP) side, for a heat exchanger of type IHX.

[0017] According to one aspect of the invention, the contact plates on each plate have widths which vary from one contact plate to the next, the width being measured, in the plane of the plate, perpendicular to a direction of elongation of the corrugations of this plate.

[0018] In particular, the contact surfaces of the plate alternate from one face to the other of the plate.

[0019] According to one aspect of the invention, the different widths of the contact plates on the plates allow in particular to have different widths between the channels of first passage section and the channels of second passage section.

[0020] This difference in width creates an asymmetry in the plates, resulting in a volume reduction in one fluid circuit and a volume increase in the other. By modifying the dimensions of the contact plates, different fluid volumes can be obtained for the two circuits of a heat exchanger of a given volume.

[0021] We can thus define, for example, high pressure side contact plates and low pressure side contact plates, for a heat exchanger of type IHX.

[0022] According to one aspect of the invention, each plate has a plurality of contact plates, including contact plates of a first width and contact plates of a second width, the second width being greater than the first width.

[0023] According to one aspect of the invention, on each plate, the first width contact plates and the second width contact plates are arranged alternately.

[0024] According to one aspect of the invention, the contact surfaces on one face of a plate may be on a vertex of a corrugation, or be on the base of a corrugation. For example, the vertex of a corrugation of one plate is brazed onto the base of a corrugation of the opposite plate.

[0025] According to one aspect of the invention, the corrugations are embossed areas of the plate.

[0026] According to one aspect of the invention, the corrugations are rectilinear.

[0027] According to one aspect of the invention, the corrugations of a plate are spaced between them with a regular pace.

[0028] Preferably, the respective corrugations of two consecutive plates are not crossed.

[0029] This allows obtaining the first section passage channels and the second section passage channels.

[0030] According to one aspect of the invention, the corrugations extend in a central area of ​​the heat exchanger, between the fluid inlet and outlet areas.

[0031] In other words, the corrugations have a length that is less than, for example at least twice less than, the length of the largest side of the perimeter of the heat exchanger.

[0032] According to one aspect of the invention, the corrugations on a plate can be of the same length, or have different lengths.

[0033] According to one aspect of the invention, the corrugations are set back from the fluid inlet and outlet area.

[0034] According to one aspect of the invention, the fluid inlet and outlet areas are also called the heat exchanger collection areas.

[0035] According to one aspect of the invention, the corrugations are arranged parallel to one side of the perimeter of the heat exchanger.

[0036] Alternatively, the corrugations can be arranged obliquely with respect to one side of the perimeter of the heat exchanger.

[0037] Preferably, the corrugations are parallel to each other for each of the plates.

[0038] According to one aspect of the invention, the corrugations are parallel to each other when moving from one plate to another.

[0039] According to one aspect of the invention, all the corrugations, and therefore the contact surfaces as well, of the heat exchanger are parallel to each other. In other words, all the corrugations and contact surfaces of the heat exchanger have the same orientation.

[0040] In one embodiment, the corrugations may have a non-zero angle between the contact flats of two consecutive plates of the stack.

[0041] For example, the contact plates of a first plate are parallel to each other and the contact plates of the next plate have a non-zero angle with the contact plates of the first plate.

[0042] According to one aspect of the invention, the contact plates are arranged so that they can be brazed together along their entire length, and, despite an inclination mutual, these contact plates are arranged to leave the channels free (and not obstruct them).

[0043] In particular, the corrugation of one plaque does not obstruct the channel formed between two corrugations of the other consecutive plaque.

[0044] In any event, the contact surfaces of one plate to the other do not cross in a cross shape.

[0045] According to one aspect of the invention, the first section passage channels and the second section passage channels have an identical height.

[0046] The height is measured perpendicular to the plane of the plates.

[0047] According to one aspect of the invention, the corrugations have an identical height when moving from one plate to the next.

[0048] Alternatively, the corrugations have different heights when moving from one plate to the next.

[0049] According to one aspect of the invention, for each fluid circuit, all the fluid inlet areas of the plate stack are connected to each other by openings in the plates which form a fluid inlet conduit.

[0050] According to one aspect of the invention, for each fluid circuit, all the fluid outlet areas of the plate stack are connected to each other by openings in the plates which form a fluid outlet conduit.

[0051] According to one aspect of the invention, for each fluid circuit, the fluid inlet area and the fluid outlet area can be diagonally opposite, or alternatively, can be on the same side of the heat exchanger.

[0052] According to one aspect of the invention, the diagonal arrangement allows for improved performance because, in this case, the fluids of the two circuits have cross-flow directions, on either side of the stack plates.

[0053] According to one aspect of the invention, the plates are made of aluminum.

[0054] According to another aspect of the invention, the heat exchanger can be a A water-cooled condenser has two fluids circulating within it: a refrigerant and a coolant, such as a water-based liquid (particularly glycol water) or a dielectric fluid. In this case, the aim is to reduce the pressure drop on the coolant side to lower the pump's energy consumption on that side.

[0055] According to one aspect of the invention, the heat exchanger can also be a liquid evaporator, or "Chiller" in English, of an air conditioning loop.

[0056] Other features, details and advantages of the invention will become clearer upon reading the following description on the one hand, and several illustrative and non-limiting examples of embodiments given with reference to the accompanying schematic drawings on the other hand, in which:

[0057] [Fig.1] Fig.1 is a schematic, perspective representation of an IHX type heat exchanger;

[0058] [Fig.2] Fig.2 is a top view of a first-type plate of the heat exchanger heat of the [Fig.l];

[0059] [Fig.3] Fig.3 is a top view of a second type plate the heat exchanger of [Fig.1];

[0060] [Fig.4] Fig.4 is a cross-sectional view of the plates of the heat exchanger heat of the [Fig.l];

[0061] [Fig. 5] Fig. 5 is a cross-sectional view of the plates of the heat exchanger. heat according to a variant;

[0062] [Fig.6] Fig.6 is a schematic top view representation of corrugations according to another embodiment of the invention.

[0063] The features, variants, and different embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of features, described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0064] Figures 1 to 3 show an internal heat exchanger 1 (also called an IHX). This type of internal heat exchanger operates with a low-pressure side (also called the LP side) and a high-pressure side (also called the HP side). In the case of an internal heat exchanger (IHX), the first and second heat transfer fluids are the same refrigerant (for example, propane for a heat pump) from the same fluid circuit but at different pressures / states (liquid / gaseous). The heat exchanger 1 is generally a block with a roughly rectangular perimeter.

[0065] The heat exchanger 1 includes inlet zones 15 and outlet zones 17 of fluid forming collecting zones of the heat exchanger 1 for the high pressure (HP) side of the refrigerant fluid.

[0066] Similarly, on the low pressure (LP) side, the heat exchanger 1 includes inlet zones 25 and outlet zones 27 of fluid forming collecting zones of the heat exchanger 1 for this low pressure (LP) side of the refrigerant fluid.

[0067] The heat exchanger 1 comprises, on the one hand, a plurality of first-type plates 10 having parallel corrugations 12 and, on the other hand, a plurality of second-type plates 20 having parallel corrugations 22. Plates of the first type 10 and plates of the second type 20 are parallel to each other and are arranged alternately to form a stack.

[0068] Corrugations 12 and 22 are parallel to each other when moving from one plate to the other.

[0069] The corrugations 12 are stamped areas of the first type plate 10. Similarly, the corrugations 22 are stamped areas of the second type plate 20.

[0070] On the first-type plates 10, the corrugations 12 have a straight, elongated shape. The corrugations 12 are parallel and spaced from each other at a regular pitch. Similarly, on the second-type plates 20, the corrugations 22 have a straight, elongated shape. The corrugations 22 are parallel and spaced from each other at a regular pitch.

[0071] Corrugations 12 and 22 extend into a central zone 30 of the heat exchanger 1, between the inlet zones 15 and 25 and the outlet zones 17 and 27.

[0072] The corrugations 12 and 22 have a length at least twice less than the length of a larger side 6 of the perimeter of the heat exchanger 1.

[0073] Corrugations 12 and 22 are set back from the inlet zones 15 and 25 and the outlet zones 17 and 27 of fluid and are arranged parallel to side 6 of the perimeter of the heat exchanger 1.

[0074] As illustrated in [Fig.4], the first type plates 10 and the second type plates 20 are arranged alternately, forming a stack of these first type plates 10 and second type plates 20. These first type plates 10 and second type plates 20, which are made of aluminum, are brazed together by a plurality of contact plates, which are here brazing plates 14, 16, 24 and 26 at the junction between consecutive first type plates 10 and second type plates 20 of the stack.

[0075] The first type plates 10 have a plurality of brazing plates 14 and 16, including brazing plates 14 of a first width and brazing plates 16 of a second width. The second width is greater than the first width. The first-width brazing plates 14 and the second-width brazing plates 16 are arranged alternately on the first type plate 10.

[0076] Similarly, the second type plates 20 have a plurality of brazing plates 24 and 26, including brazing plates 24 of a first width and brazing plates 26 of a second width. The second width is greater than the first width. The first-width brazing plates 24 and the second-width brazing plates 16 are arranged alternately on the second type plate 20.

[0077] The width is measured, in a plane P of the first type plates 10 and second type plates 20, and perpendicular to an elongation direction EL of the corrugations 12 and 22.

[0078] The corrugations 12 and 22 and therefore also the brazing plates 14, 16, 24 and 26, are parallel to each other, and consequently, are in the same orientation.

[0079] On the first type plate 10, the first width brazing plates 14 are formed on one face of this first type plate 10 and on a vertex 120 of the corrugation 12. The second width brazing plates 16 are formed on an opposite face of the first type plate 10 and on a base 122 of the corrugation 12.

[0080] On the other hand, on the second type plate 20, the first width brazing plates 24 are formed on one face of the second type plate 20 and on a base 222 of the corrugation 22. The second width brazing plates 26 are formed on an opposite face of the second type plate 20 and on a vertex 220 of the corrugation 22. For example, the vertex 120 of the corrugation 12 of the first type plate 10, relative to the first width brazing plate 14, is brazed onto the base 222 of the corrugation 22 of the second type plate 20 opposite, relative to the first width brazing plate 24.

[0081] Corrugations 12 and 22 define channels 42 and 44 between the consecutive first-type plates 10 and second-type plates 20. The channels 42 allow fluid to pass between a fluid inlet zone 15 and a fluid outlet zone 17 on the high-pressure (HP) side. On the low-pressure (LP) side, the channels 44 allow fluid to pass between the fluid inlet zone 25 and the fluid outlet zone 27.

[0082] The channels 42 of the first passage section are configured to form the high-pressure side 52. The channels 44 of the second passage section, larger than the first passage section of the channels 42, are configured to form the low-pressure side 54.

[0083] The brazing plates 14 and 24 of the first width are on the high pressure side 52 and the brazing plates 16 and 26 of the second width are on the low pressure side 54, for the heat exchanger 1.

[0084] Thus, the difference in width of the brazing plates 14, 16, 24, and 26 creates a difference between the first fluid passage section of the channels 42 and the second fluid passage section of the channels 44. This results in an asymmetry in the first-type plates 10 and second-type plates 20 in order to reduce the fluid volume on the high-pressure side 52 compared to the low-pressure side 54. The fluid volume distribution ratio between the high-pressure side 52 and the low-pressure side 54 is between 1.5 and 3. For example, there is 1.5 times more fluid on the low-pressure side 54 than on the high-pressure side 52.

[0085] The first fluid passage channel 42 and the second fluid passage channel 44 alternate on either side of the first type plates 10 and second type plates 20. This means that the first passage channel 42 is formed by joining the first type plate 10 with the second type plate 20 in a predetermined stacking direction. The second passage channel 44 is also formed by joining the first type plate 10 with the second type plate 20 in a predetermined stacking direction.

[0086] In the example described, as can be seen in particular in Figures 2 and 3, the fluid inlet zones 15 and 25 and the fluid outlet zones 17 and 27 have fluid flow disturbance features 70, called "Dimples" in English. The disturbance features 70 are distinct from the corrugations 12 and 22 which form the channels 42 and 44.

[0087] The disturbance reliefs 70 are formed by stamped shapes and are rounded or oval in shape, for example in the shape of a cap. These disturbance reliefs 70 increase the heat transfer coefficient.

[0088] Figures 2 and 3 show that, for the high pressure side 54, the inlet areas 25 are connected to each other by openings 74 in the first type plates 10 and second type plates 20 which form a fluid inlet conduit 78.

[0089] For the low pressure side 52, the inlet areas 15 are connected to each other by openings 72 in the first type plates 10 and second type plates 20 which form a fluid inlet conduit 76.

[0090] For the high pressure side 52, the outlet areas 17 are connected to each other by openings 71 in the first type plates 10 and second type plates 20 which form a fluid outlet conduit 75.

[0091] For the low pressure side 54, the outlet areas 27 are connected to each other by openings 73 in the first type plates 10 and second type plates 20 which form a fluid outlet conduit 77.

[0092] Finally, the fluid inlet zones 15 and 25 and the fluid outlet zones 17 and 27 are diagonally opposed. The diagonal arrangement allows for improved performance because, in this case, the high-pressure side 52 and low-pressure side 54 have cross flow directions, on either side of the first-type plates 10 and second-type plates 20 of the stack.

[0093] Figure 4 shows that the corrugations 12 of the first-type plate 10 and the corrugations 22 of the second-type plate 20 have different heights. The corrugations 12 and 22 have, respectively, a large height called H1 and the same small height called H2. The heights H1 and H2 are measured perpendicular to the plane P of the plates.

[0094] The channels 42 of the first passage section and the channels 44 of the second passage section have the same height HC. The height HC of channels 42 and 44 is equal to the sum of the major height H1 of the corrugation 12 and the minor height H2 of the corrugation 22.

[0095] In a variant illustrated in [Fig. 5], the corrugations 12 of the first-type plate 10 and the corrugations 22 of the second-type plate 20 have an identical height H5. The height H5 is measured perpendicular to the plane P of the plates.

[0096] In this variant, channels 42 and 44 have an identical height HC which is equal to the sum of the height H5 of the corrugation 12 and the height H5 of the corrugation 22.

[0097] According to another embodiment of the invention illustrated in [Fig.6], the corrugations 22 are arranged obliquely with respect to the side 6 of the periphery of the heat exchanger 1. The corrugations 22 are oriented along an elongation axis ELI of the second type plate 20 and the corrugations 12 are oriented along an elongation axis EL2 of the first type plate 10.

[0098] The elongation axis ELI of the second type plate 20 is inclined with respect to the elongation axis EL2 of the first type plate 10 at a non-zero angle ANG, for example of about 10° or 20°.

[0099] The corrugations 12 and 22 do not obstruct the channels 42 and 44 formed between two corrugations 12 and 22 of the first type plates 10 and second type plates 20.

[0100] The brazing plates 14 and 24 of first width and the brazing plates 16 and 26 of second width, between the plate of first type 10 and the plate of second type 20, do not cross to form a cross.

Claims

Demands

1. A heat exchanger (1), in particular of the internal heat exchanger type, also called an IHX, comprising: - a plurality of first-type plates (10) provided with corrugations (12), - a plurality of second-type plates (20) provided with corrugations (22), the first-type plates (10) and the second-type plates (20) being arranged alternately in a plate stack, the first-type plates (10) and the second-type plates (20) being joined together, in particular brazed together, by a plurality of contact plates (14, 16, 24, 26) at the junction between two consecutive plates of the stack, - the corrugations (12, 22) of the plates having a generally elongated shape and defining, between consecutive plates, channels (42, 44) allowing the passage of fluid between a fluid inlet zone (15, 25) and an outlet zone (17, 27) of fluid, these channels (42,44) being distributed between channels (42) of the first fluid passage section and channels (44) of the second fluid passage section, the channels (42) of the first passage section of the heat exchanger (1) and the channels (44) of the second passage section of the heat exchanger (1) being alternated on either side of the stack plates, the channels (42) of the first passage section of the heat exchanger (1) being configured to form a first fluid circuit for a first heat transfer fluid and the channels (44) of the second passage section of the heat exchanger (1) being configured to form a second fluid circuit for a second heat transfer fluid, - the first fluid passage section of the channels (42) being smaller than the second fluid passage section of the channels (44).

2. Heat exchanger (1) according to claim 1, wherein the contact plates (14, 16, 24, 26) on each plate have widths that vary from one contact plate (14, 16, 24, 26) to the next, the width being measured, in the plane of the plate, perpendicular to a direction of elongation of the corrugations (12, 22) of this plate.

3. Heat exchanger (1) according to claim 2, wherein each plate has a plurality of contact plates (14, 16, 24, 26), including contact plates (14, 24) of a first width and contact plates (16, 26) of a second width, the second width being greater than the first width, preferably, the contact plates (14, 24) of first width and the contact plates (16, 26) of second width are arranged alternately.

4. Heat exchanger (1) according to any one of the preceding claims, wherein the contact plates (14, 16, 24, 26) on one face of the plate are on a crest (120, 220) of the corrugation (12, 22), or on a base (122, 222) of the corrugation (12, 22), for example, the crest (120, 220) of the corrugation (12, 22) of the plate is brazed onto the base (122, 222) of a corrugation (12, 22) of the other plate opposite.

5. Heat exchanger (1) according to any one of the preceding claims, wherein the corrugations (12, 22) are stamped areas of the plate.

6. Heat exchanger (1) according to any one of the preceding claims, wherein the corrugations (12, 22) are straight, and preferably extend in a central area (30) of the heat exchanger (1), between the fluid inlet area (15, 25) and outlet area (17, 27).

7. Heat exchanger (1) according to any one of the preceding claims, wherein the corrugations (12, 22) of the plate are spaced from each other with a regular pitch, and preferably, the respective corrugations (12, 22) of two consecutive plates are not crossed.

8. Heat exchanger (1) according to any one of the preceding claims, wherein the corrugations (12, 22) have the same height when moving from one plate to the next.

9. Heat exchanger (1) according to any one of claims 1 to 8, wherein the corrugations (12, 22) have different heights when moving from one plate to the next.

10. Heat exchanger (1) according to any one of the preceding claims, defining an internal heat exchanger, also called IHX.

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