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(11) | EP 2 865 980 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Heat exchanger |
| (57) A heat exchanger including a plurality of tubes disposed horizontally, a pair of
vertical headers connecting the tubes, and at least one flow distribution baffle mounted
to a header at one group of the plurality of tubes such that the flow distribution
baffle is positioned between tubes of the one group. Each of the at least one flow
distribution baffle is provided with at least one distribution hole allowing a refrigerant
to pass therethrough. The heat exchanger prevents unbalanced distribution of the refrigerant
when it operates as an evaporator of an outdoor unit.
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[0001] The present invention relates to a heat exchanger, particularly to a heat exchanger provided with a header having an improved performance of distribution of a refrigerant.
[0002] A heat exchanger, which is an apparatus causing a refrigerant to exchange heat with external air, generally includes tubes having a refrigerant flowing therethrough and arranged to exchange heat with external air, a heat exchange fin contacting the tubes to increase the heat dissipation area, and a header allowing ends of the tubes to communicate with each other in order to guide the refrigerant to the tubes and adapted to support the tubes.
[0003] Heat exchangers include a fin tube type heat exchanger, which is configured by inserting a heat transfer pipe formed of copper into a thin heat exchange fin formed of aluminum, and a parallel flow type heat exchanger, which is configured by disposing the heat exchange fin between the tubes having multiple micro-channels and formed of aluminum and arranging the tubes such that they are supported by a pair of headers. The parallel flow type heat exchanger is known to be relatively inexpensive and have high efficiency.
[0004] In the case that a parallel flow type heat exchanger with vertical headers is used as an evaporator of an outdoor unit, distribution of a refrigerant from the vertical headers to the tubes becomes unbalanced due to gravity and variation of physical properties of the refrigerant according to a physical phase of the refrigerant. Thereby, the refrigerant may be distributed only to some of the tubes. For this reason, the parallel flow type heat exchanger is often used only as a condenser.
[0005] Therefore, it is an aspect of the present invention to provide a parallel flow type heat exchanger having vertical headers which allow a refrigerant introduced into the headers to be uniformly distributed to the tubes even when the heat exchanger operates as an evaporator of an outdoor unit, thereby preventing degradation of heat exchange performance.
[0006] Additional aspects of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
[0007] In accordance with one aspect of the present invention, a heat exchanger includes a plurality of tubes disposed horizontally, a heat exchange fin to contact the tubes, a first header vertically disposed to communicate with one end of each of the tubes, a second header vertically disposed to communicate with the other end of each of the tubes, at least one flow passage defining baffle mounted to at least one header of the first header and the second header and adapted to define a flow passage of a refrigerant by interrupting flow of the refrigerant in the at least one header in a longitudinal direction and to divide the tubes into n (n ≥ 2, where n is an even number) groups, each of the groups having tubes adjoining each other and allowing the refrigerant to flow in one direction therethrough and the number of the at least one flow passage defining baffle being n-1, and at least one flow distribution baffle mounted to a corresponding header of the first header and the second header arranged at an inlet of one group of the n groups such that the flow distribution baffle is positioned between the tubes belonging to the one group, each of the at least one flow distribution baffle being provided with at least one distribution hole allowing the refrigerant to pass therethrough.
[0008] The flow distribution baffle may be positioned between the tubes belonging to the last group of the n groups arranged in a direction of flow of the refrigerant when the heat exchanger operates as an evaporator.
[0009] The distribution hole may be spaced from an inner side surface of the corresponding header at an opposite side to the tubes of the corresponding header such that flow of the refrigerant along the inner side surface at the opposite side is interrupted.
[0010] A cross section of each of the at least one distribution hole may have a shape of one of polygon, circle, and other different closed figures.
[0011] The at least one distribution hole may include a hole formed in the flow distribution baffle and a hole formed between the flow distribution baffle and the inner side surface of the corresponding header by mounting the flow distribution baffle to the corresponding header.
[0012] A total cross-sectional area of the at least one distribution hole may be 1 % to 40 % of a cross-sectional area of an inner surface of the corresponding header.
[0014] Here, n = 4, the number of the at least one flow passage defining baffle may be 3, and the tubes may be divided into four groups.
[0015] One header of the first header and the second header may be provided with an inlet pipe and an outlet pipe, and the flow distribution baffle may be mounted to the other header of the first header and the second header.
[0016] The refrigerant may flow upward in the first header and the second header when the heat exchanger operates as an evaporator, and the refrigerant may flow downward in the first header and the second header when the heat exchanger operates as a condenser.
[0017] The heat exchanger may further include at least one flow speed boosting baffle mounted to a corresponding header of the first header and the second header arranged at an inlet of one group of the n groups such that the flow speed boosting baffle is positioned between the one group and another group positioned immediately ahead of the one group in a direction of flow of the refrigerant when the heat exchanger operates as an evaporator, each of the at least one flow speed boosting baffle being provided with at least one boosting hole allowing the refrigerant to pass therethrough.
[0018] The at least one flow speed boosting baffle may be positioned between the last group of the n groups arranged in the direction of flow of the refrigerant and another group immediately ahead of the last group when the heat exchanger operates as the evaporator.
[0019] A cross section of each of the at least one boosting hole may have a shape of one of polygon, circle, and other different closed figures.
[0020] A total cross-sectional area of the at least one boosting hole may be 5 % to 70 % of a cross-sectional area of an inner space of the corresponding header.
[0021] A total cross-sectional area of the at least one boosting hole may be greater than the total cross-sectional area of the at least one distribution hole.
[0022] In accordance with another aspect of the present invention, a heat exchanger includes a plurality of tubes disposed horizontally, a heat exchange fin to contact the tubes, a first header vertically disposed to communicate with one end of each of the tubes, a second header vertically disposed to communicate with the other end of each of the tubes, at least one flow passage defining baffle mounted to at least one header of the first header and the second header and adapted to define a flow passage of a refrigerant by interrupting flow of the refrigerant in the at least one header in a longitudinal direction and to divide the tubes into n (n ≥ 2, where n is an even number) groups, each of the groups having tubes adjoining each other and allowing the refrigerant to flow in one direction therethrough and the number of the at least one flow passage defining baffle being n-1, and at least one flow speed boosting baffle mounted to a corresponding header of the first header and the second header arranged at an inlet of one group of the n groups such that the flow speed boosting baffle is positioned between the one group and another group positioned immediately ahead of the one group in a direction of flow of the refrigerant when the heat exchanger operates as an evaporator, each of the at least one flow speed boosting baffle being provided with at least one boosting hole allowing the refrigerant to pass therethrough.
[0023] The at least one flow speed boosting baffle may be positioned between the last group of the n groups arranged in the direction of flow of the refrigerant and another group immediately ahead of the last group when the heat exchanger operates as the evaporator.
[0024] A cross section of each of the at least one boosting hole may have a shape of one of polygon, circle, and other different closed figures.
[0025] A total cross-sectional area of the at least one boosting hole may be 5 % to 70 % of a cross-sectional area of an inner space of the corresponding header.
[0026] In accordance with another aspect of the present invention, a heat exchanger includes a plurality of tubes disposed horizontally, a heat exchange fin to contact the tubes, a first header vertically disposed to communicate with one end of each of the tubes and provided with an inlet pipe and an outlet pipe, a second header vertically disposed to communicate with the other end of each of the tubes, at least one flow passage defining baffle mounted to at least one header of the first header and the second header and adapted to define a flow passage of a refrigerant by interrupting flow of the refrigerant in the at least one header in a longitudinal direction and to divide the tubes into a plurality of groups, each of the groups having tubes adjoining each other and allowing the refrigerant to flow in one direction therethrough, and at least one flow distribution baffle mounted to the second header such that a supply section of the second header to supply the refrigerant to the tubes belonging to one of the groups positioned at an uppermost side is partitioned into an upper section communicating one portion of the tubes and a lower section communicating with the other portion of the tubes, each of the at least one flow distribution baffle being provided with at least one distribution hole allowing the refrigerant to pass therethrough, wherein one portion of the refrigerant directed from the lower section to the upper section is distributed to the one portion of the tubes communicating with the upper section through the at least distribution hole, and the other portion of the refrigerant fails to pass through the at least one distribution hole and is distributed to the other portion of the tubes communicating with the lower section.
[0027] The heat exchanger may further include a flow speed boosting baffle mounted to the second header to be positioned between the supply section and an introduction section of the second header and provided with at least one boosting hole allowing the refrigerant to flow therethrough, the introduction section being positioned immediately under the supply section to receive the refrigerant from the tubes of another one of the groups positioned immediately under the group positioned at the uppermost side, wherein a flow speed of the refrigerant flowing from the introduction section to the supply section through the at least one boosting hole is boosted by boosting pressure in the introduction section.
[0028] These and/or other aspects of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:
FIG. 1 is a view illustrating an external appearance of a heat exchanger according to an exemplary embodiment of the present invention;
FIG. 2 is an exploded view illustrating constituents of a second header of the heat exchanger shown in FIG. 1;
FIG. 3 is an exploded view illustrating constituents of a first header of the heat exchanger shown in FIG. 1;
FIG. 4 is a front view illustrating the heat exchanger of FIG. 1;
FIG. 5 is a view illustrating main parts of the heat exchanger of FIG. 1;
FIG. 6 is a cross-sectional view taken along line I-I of FIG. 1;
FIGS. 7 to 11 are cross-sectional views illustrating flow distribution baffles according to other embodiments of the present invention;
FIG. 12 is a cross-sectional view illustrating a flow speed boosting baffle of the heat exchanger of FIG. 1;
FIG. 13 is a cross-sectional view illustrating a header and a flow distribution baffle according to another embodiment of the present invention;
FIG. 14 is a view illustrating overall flow of a refrigerant in a cooling and heating system according to an embodiment of the present invention;
FIG. 15 is a view illustrating flow of the refrigerant when the heat exchanger of FIG. 1 operates as a condenser; and
FIG. 16 is a view illustrating flow of the refrigerant when the heat exchanger of FIG. 1 operates as an evaporator.
[0029] Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.
[0030] Referring to FIGS. 1 to 3, the heat exchanger 10 is a parallel flow type heat exchanger having a vertical header. The heat exchanger 10 includes a plurality of tubes 60 having a refrigerant flowing therethrough and may be horizontally disposed to exchange heat with external air, a pair of headers 20 and 30 vertically disposed to guide the refrigerant to the tubes 60 and communicate with the tubes 60, and a heat exchange fin 50 to contact the tubes 60.
[0031] The tubes 60 may be formed of aluminum in a flat shape and provided therein with microchannels 61 allowing the refrigerant to flow therethrough. The tubes 60 are horizontally disposed and spaced a certain distance from each other.
[0032] The heat exchange fin 50 may take various forms that increase the heat transfer area and facilitate drainage of condensated water, and may be formed of aluminum. The heat exchange fin 50 may be arranged between the tubes 60 and joined to the tubes 60 by brazing.
[0033] Headers 20 and 30 may be vertically disposed and spaced a predetermined distance from each other, with the tubes 60 placed therebetween. Hereinafter, for simplicity of illustration, the header 20 disposed on the right side of the tubes 60 in FIG. 1 will be defined as a first header 20 and the header 30 disposed on the left side of the tubes 60 will be defined as a second header 30.
[0034] The first header 20 and the second header 30 may be formed approximately in the shape of a cylinder having an inner space. Accordingly, the cross sections of the first header 20 and the second header 30 are approximately formed in the shape of a circle. However, embodiments of the present invention are not limited thereto. The cross sections may be formed approximately in a "D" shape or other shapes.
[0035] The first header 20 and the second header 30 may be respectively formed by coupling cylindrical bodies 21 and 31 with inner spaces 22 and 32 and open opposites ends to upper caps 25 and 35 and lower caps 26 and 36 covering open opposite ends of the bodies 21 and 31. The bodies 21 and 31, the upper caps 25 and 35, and the lower caps 26 and 36 may all be formed of aluminum and coupled by brazing.
[0036] Tube insertion holes 23 and 33 allowing the tubes 60 to be inserted thereinto are formed on one side surface of each of the bodies 21 and 31. Opposite ends of each of the tubes 60 may be inserted into and joined to the tube insertion holes 23 and 33 by brazing. Thereby, the microchannels 61 of the tubes 60 may communicate with the inner space 22 and 32 of the first header 20 and the second header 30, and the refrigerant may flow between the headers 20 and 30 and the tubes 60.
[0037] The other side surfaces of the bodies 21 and 31 are provided with baffle insertion holes 24 and 34 allowing baffles 70, 80, 90 and 100 to be inserted thereinto. Flow passage defining baffles 70 may be inserted into the baffle insertion holes 24 of the first header 20. A flow passage defining baffle 70, a flow speed boosting baffle 100, and flow distribution baffles 80 and 90 may be inserted into the baffle insertion holes 34 of the second header 30.
[0038] Configurations and functions of the flow passage defining baffle 70, the flow speed boosting baffle 100, and the flow distribution baffles 80 and 90 will be described in detail later. The baffles 70, 80, 90 and 100 may be inserted into the baffle insertion holes 24 of the first header 20 or the second header 30 in the direction inwardly extending from the exterior of the heat exchanger 10.
[0039] The baffles 70, 80, 90 and 100 may all be formed of aluminum and joined to the baffle insertion holes 24 by brazing after being inserted into the baffle insertion holes 24. Meanwhile, the first header 20 may be provided with an inlet pipe 27 and an outlet pipe 28 through which the refrigerant flows into and out of the first header 20. The inlet pipe 27 may be provided to a lower portion of the first header 20, and the outlet pipe 28 may be provided to an upper portion of the first header 20.
[0040] When the heat exchanger 10 operates as an evaporator of the outdoor unit in this embodiment, the refrigerant in a liquid state or gaseous state may be introduced through the inlet pipe 27. The introduced refrigerant may be evaporated after absorbing heat from external air while passing through the tubes 60. There, it may be discharged through the outlet pipe 28 in the gaseous state.
[0041] When the heat exchanger 10 operates as a condenser of the outdoor unit in this embodiment, the refrigerant in the gaseous state may be introduced through the outlet pipe 28. The introduced refrigerant may lose heat to the external air while passing through the tubes 60. Then, the refrigerant may be condensed into the liquid state and discharged through the inlet pipe 27.
[0042] The heat exchanger 10, which may operate as an evaporator and condenser of the outdoor unit vertical headers 20 and 30 as described above, is a parallel flow type heat exchanger. Particularly, when the heat exchanger 10 operates as the evaporator of the outdoor unit, the flow distribution baffles 80 and 90 and flow speed boosting baffle 100 provided to the second header 30 may ensure that the refrigerant is evenly distributed, thereby enhancing heat exchange efficiency.
[0043] Hereinafter, a detailed description will be given of configurations and functions of the flow passage defining baffle 70, the flow distribution baffles 80 and 90 and the flow speed boosting baffle 100.
[0044] FIG. 4 is a front view illustrating the heat exchanger of FIG. 1, FIG. 5 is a view illustrating main parts of the heat exchanger of FIG. 1, and FIG. 6 is a cross-sectional view taken along line I-I of FIG. 1. FIGS. 7 to 11 are cross-sectional views illustrating flow distribution baffles according to other embodiments of the present invention. FIG. 12 is a cross-sectional view illustrating a flow speed boosting baffle of the heat exchanger of FIG. 1. FIG. 13 is a cross-sectional view illustrating a header and a flow distribution baffle according to another embodiment of the present invention.
[0045] The arrows shown in FIGS. 4 and 5 indicate flow of the refrigerant when the heat exchanger 10 operates as the evaporator of the outdoor unit.
[0046] Referring to FIGS. 4 to 6, two flow passage defining baffles 70 are mounted to the first header 20, and one flow passage defining baffles 70 is mounted to the second header 30. Thereby, the heat exchanger 10 is provided with three flow passage defining baffles 70, which are disposed at different vertical levels.
[0047] The three flow passage defining baffles 70 interrupt flow of the refrigerant in the headers 20 and 30 in the longitudinal direction of the headers 20 and 30. Accordingly, the refrigerant introduced into the first header 20 through the inlet pipe 27 provided to a lower portion of the first header 20 rises in a zigzag form, repeatedly passing through the first header 20, the tubes 60 and the second header 30 as indicated by arrows in FIG. 4.
[0048] That is, the flow passage defining baffles 70 define a flow passage of the refrigerant. At this time, the tubes 60 are classified into a plurality of groups A, B, C and D. Tubes classified into the same group adjoin each other and allow the refrigerant to flow therethrough in the same direction.
[0049] In this embodiment, the tubes 60 are divided into tubes of one group (hereinafter, group A) disposed adjacent to each other at the lowest position and causing the refrigerant to flow from the first header 20 to the second header 30 therethrough, tubes of another group (hereinafter, group B) disposed adjacent to each other on the tubes of group A and causing the refrigerant to flow from the second header 30 to the first header 20 therethrough, tubes of another group (hereinafter, group C) disposed adjacent to each other on the tubes of group B and causing the refrigerant to flow from the first header 20 to the second header 30 therethrough, and tubes of the other group (hereinafter, group D) disposed adjacent to each other on the tubes of group C and causing the refrigerant to flow from the second header 30 to the first header 20 therethrough. Herein, each of the groups may include 2 to 15 tubes.
[0050] As described above, the heat exchanger 10 of this embodiment is provided with three flow passage defining baffles 70, and the tubes 60 are divided into four groups by the three flow passage defining baffles 70.
[0051] Herein, the first header 20 of the pair of headers 20 and 30 is provided with both the inlet pipe 27 and the outlet pipe 28. In this context, when the number of the flow passage defining baffles 70 is n - 1, the number of groups of tubes is n, where n is an even number greater than 2. The number of the flow passage defining baffles 70 may be greater or less than 3, and the number of groups of the tubes may also be greater or less than the number illustrated in FIG. 4.
[0052] In short, the heat exchanger according to an embodiment of the present invention may have n - 1 flow passage defining baffles that divide the tubes 60 into n (n ≥ 2, where n is an even number) groups, each of which has tubes adjoining each other and causing the refrigerant to flow in one direction.
[0053] Meanwhile, the flow distribution baffles 80 and 90 are provided to ensure that the refrigerant in the header 30 is evenly distributed to the tubes 60. In this embodiment, two flow distribution baffles 80 and 90 are mounted to an upper portion of the second header 30.
[0054] The number of the flow distribution baffles is not limited. Depending upon various factors such as the number and length of the tubes 60 and pressure of the refrigerant, one flow distribution baffle may be provided, or two, three or more flow distribution baffles may be provided.
[0055] The two flow distribution baffles 80 and 90 of this embodiment substantially have the same shape and function, and therefore only the flow distribution baffle 80 disposed at a lower position of the two flow distribution baffles 80 and 90 will be described.
[0056] The shape of the flow distribution baffle 80 will be discussed first. As shown in FIG. 6, the flow distribution baffle 80 may include an interruption wall 89 arranged perpendicular to the longitudinal direction of the header to interrupt flow of the refrigerant in the header in the longitudinal direction of the header, a distribution hole 81 (91 for the flow distribution baffle 90) formed in the interruption wall 89 to allow the refrigerant to flow in the header in the longitudinal direction of the header, and a stopper 88 protruding from opposite sides of the interruption wall 89 to restrict the insertion depth of the flow distribution baffle 80.
[0057] The interruption wall 89 may closely contact the inner side surface of the header to interrupt flow of the refrigerant, and thus the refrigerant directed to the flow distribution baffle 80 may be allowed to flow via the flow distribution baffle 80 only by passing through the distribution hole 81.
[0058] Particularly, the distribution hole 81 needs to be spaced a predetermined distance G from the inner side surface 37 on the opposite side facing the tubes in the header such that flow of the liquid refrigerant along the inner side surface 37 on the opposite side facing the tubes is interrupted.
[0059] The distribution hole 81 may be formed in any shape. In addition, the number of the distribution holes is not limited. That is, the distribution hole shown in FIG. 6 has a rectangular cross section. However, embodiments of the present invention are not limited thereto. For example, the flow distribution baffle 82 may be provided with a distribution hole 82a having a circular cross section as shown in FIG. 7. Alternatively, a flow distribution baffle 83 may be provided with a distribution hole 83a whose cross section is formed in the shape of multiple slits, as shown in FIG. 8. Alternatively, a flow distribution baffle 84 may be provided with a distribution hole 84a whose cross section has the shape of a closed figure different from a circle and a rectangle, as shown in FIG. 9. Alternatively, a flow distribution baffle 85 may have a porous distribution hole 85a as shown in FIG. 10.
[0060] The distribution hole of the flow distribution baffle 82 may include not only the hole formed in the flow distribution baffle 82 but also a hole defined between the flow distribution baffle 82 and the header. That is, a hole 86a defined between one surface 86b of the flow distribution baffle 82 and the inner side surface 38 of the header 31 by mounting the flow distribution baffle 86 to the header 31 is also provided as a distribution hole 86a of the flow distribution baffle 86, as shown in FIG. 11.
[0061] Meanwhile, the flow distribution baffle 80 is applicable not only to a header having a circular cross section but also to a header having a cross section formed in a shape different from a circle.
[0062] That is, even in the case that the cross section of the header 39 is approximately formed in a "D" shape as shown in FIG. 13, a flow distribution baffle 87 with a distribution hole 87a may be mounted to the header 39.
The sum of the cross-sectional area of the distribution hole 81 in the flow distribution baffle 80 may be 1 to 40 % of the cross-sectional area of the inner space of the header.
[0063] Hereinafter, the mounting position and function of the flow distribution baffle 80 will be described with reference to FIG. 5.
[0064] For simplicity of illustration, a portion of the inner space of the second header 30 that supplies the refrigerant to the tubes of group D will be defined as a supply section 40. Thereby, the lower end of the supply section 40 in the second header is limited by the flow speed boosting baffle 100, and the upper end thereof is limited by the upper cap 35. In the supply section 40, the refrigerant generally rapidly flows upward. Particularly, the liquid refrigerant rapidly rises along the inner side surface of the second header 30 facing the tube 60. Accordingly, the refrigerant is not evenly distributed to the tubes of the group D in the supply section 40. That is, most of the refrigerant is distributed to some of the tubes of group D which are positioned at the upper side, and little refrigerant is distributed to the other tubes of group D positioned at the lower side.
[0065] The flow distribution baffle 80 according to one embodiment is mounted in the supply section 40 to ensure that the refrigerant of the supply section 40 is evenly distributed to all the tubes of group D.
[0066] Specifically, the flow distribution baffle 80 is mounted to the second header 30 such that it is positioned between the tubes of group D. Herein, positioning the flow distribution baffle 80 between the tubes of group D means that at least one of the tubes of group D is positioned over the flow distribution baffle 80, and at least one of the tubes of group D is positioned under the flow distribution baffle 80.
[0067] The supply section 40 is partitioned into two spaces by the flow distribution baffle 80. For simplicity of illustration, one of the two spaces positioned over the flow distribution baffle 80 is defined as an upper section 41, and the other space positioned under the flow distribution baffle 80 is defined as a lower section 42.
[0068] Flow of the refrigerant is directed upward in the supply section 40, and thus the refrigerant flows from the lower section 42 to the upper section 41. At this time, the refrigerant flowing from the lower section 42 to the upper section 41 is interrupted by the flow distribution baffle 80 since the flow distribution baffle 80 is installed between the lower section 42 and the upper section 41. Thereby, only a portion of the refrigerant flows into the upper section 41 through the distribution hole 81, the other portion of the refrigerant fails to pass through the distribution hole 81 and is caused to horizontally flow into the tubes communicating with the lower section 42.
[0069] Particularly, the liquid refrigerant rising fast along the inner side surface of the header facing the tubes is resisted by the flow distribution baffle 80, and mixing of the refrigerant may occur in the lower section 42.
[0070] Through the above structural configuration, the flow distribution baffle 80 may improve distribution of the refrigerant to the tubes 60 in the header 30.
[0071] While the flow distribution baffle 80 of this embodiment is illustrated as being mounted to an upper portion of the second header communicating with the tubes of group D, embodiments of the present invention are not limited thereto. The flow distribution baffle may be mounted to any portion of the second header where fast flow causes uneven distribution of the refrigerant, according to the specifications of the heat exchanger refrigerant.
[0072] Meanwhile, the flow speed boosting baffle 100 is provided to increase the flow speed of the refrigerant in the header 30 to improve distribution of the refrigerant. In this embodiment, one flow speed boosting baffle 100 is mounted to the middle portion of the second header 30.
[0073] The number of the flow speed boosting baffles 100 is not limited thereto. Depending upon the specifications of the heat exchanger, two or more flow speed boosting baffles may be provided. If unnecessary, they may not be provided.
[0074] Regarding the configuration of the flow speed boosting baffle 100, the flow speed boosting baffle 100 has at least one boosting hole 101 allowing the refrigerant to pass therethrough, as shown in FIG. 12. The flow speed boosting baffle 100 has almost the same shape as the flow distribution baffle 80.
[0075] The sum of the cross-sectional area of the at least one boosting hole 101 in the flow speed boosting baffle 100 may occupy 5 % to 70 % of the cross-sectional area of the inner space of the header. Accordingly, the sum of the cross-sectional area of the at least one boosting hole 101 in the flow speed boosting baffle 100 is generally greater than the sum of the cross-sectional area of the at least one distribution hole 81 in the flow distribution baffle 80.
[0076] The shape of the boosting hole 101 in the flow speed boosting baffle 100 is not limited. Unlike the distribution hole 81 in the flow distribution baffle 80, the boosting hole 101 in the flow speed boosting baffle 100 is not necessarily spaced from the inner side surface of the header facing the tubes.
[0077] Hereinafter, the mounting position and function of the flow speed boosting baffle 100 will be described with reference to FIG. 5.
[0078] For simplicity of illustration, a portion of the inner space of the second header 30 positioned under the supply section 40 to receive the refrigerant from the tubes of group C will be defined as an introduction section 43.
[0079] The flow speed boosting baffle 100 is mounted to the second header 30 such that it is positioned between the supply section 40 and the introduction section 43. That is, the flow speed boosting baffle 100 is mounted to the second header 30 such that it is positioned between the tubes of group D and the tubes of group C.
[0080] In the introduction section 43, the refrigerant is caused to flow upward to the supply section 40 by the refrigerant introduced from the tubes of group C. At this time, the refrigerant flowing from the introduction section 43 to the supply section 40 is interrupted since the flow speed boosting baffle 100 is installed between the supply section 40 and the introduction section 43. Thereby, the pressure of the refrigerant in the introduction section 43 increases.
[0081] Accordingly, the flow speed of the refrigerant flowing from the introduction section 43 to the supply section 40 is boosted when the refrigerant passes through the boosting hole 101 in the flow speed boosting baffle 100.
[0082] As such, in the case that the refrigerant flows in the header 30 at low speed and is thus insufficiently supplied to the upper end of the header 30 and concentrated at the lower portion of the header, the flow speed may be increased by installing the flow speed boosting baffle. In the case that the refrigerant is sufficiently supplied to the upper end, the flow speed boosting baffle may not be necessary.
[0083] FIG. 14 is a view illustrating overall flow of a refrigerant in a cooling and heating system according to an embodiment of the present invention, FIG. 15 is a view illustrating flow of the refrigerant when the heat exchanger of FIG. 1 operates as a condenser, and FIG. 16 is a view illustrating flow of the refrigerant when the heat exchanger of FIG. 1 operates as an evaporator.
[0084] Hereinafter, operation of a cooling and heating system with the heat exchanger according to an embodiment of the present invention will be described with reference to FIGS. 14 to 16.
[0085] A two-way heat pump cooling and heating system may include an outdoor unit 1 and an indoor unit 2. The outdoor unit 1 may include a first heat exchanger 10 according to one embodiment, a compressor 3 to compress the refrigerant, and an expansion unit 4 to expand the refrigerant and a switching valve 5 to switch the flow passage of the refrigerant, and the indoor unit 2 may include a second heat exchanger 11.
[0086] In a cooling mode, the refrigerant flows sequentially through the compressor 3, the first heat exchanger 10, expansion unit 4, and the second heat exchanger 11 along the solid arrows. Accordingly, the first heat exchanger 10 operates as a condenser, and the second heat exchanger 11 operates as an evaporator.
[0087] As shown in FIG. 15, in the cooling mode, the gaseous refrigerant turned to a high-temperature and high-pressure refrigerant by being compressed in the compressor 3 is introduced into the outlet pipe 28 of the first heat exchanger 10. The introduced refrigerant is condensed by losing heat to the external air as it flows down in a zigzag pattern. The condensed refrigerant is discharged through the inlet pipe 27.
[0088] In a heating mode, the refrigerant flows sequentially through the compressor 3, the second heat exchanger 11, expansion unit 4, and the first heat exchanger 10 along the dotted arrows. Accordingly, the first heat exchanger 10 operates as an evaporator, and the second heat exchanger 11 operates as a condenser.
[0089] As shown in FIG. 16, in the heating mode, the liquid or gaseous refrigerant turned into a low-temperature and low-pressure refrigerant by being expanded in the expansion unit 4 is introduced into the inlet pipe 27 of the first heat exchanger 10. The introduced refrigerant is evaporated by absorbing heat as it flows upward in a zigzag pattern. The evaporated refrigerant is discharged through the outlet pipe 28.
[0090] When the first heat exchanger 10 of the parallel flow type having vertical headers operates as an evaporator, distribution of the refrigerant may become unbalanced due to the physical properties of the liquid refrigerant and gravity.
[0091] Particularly, the flow speed of the refrigerant rising up in the second header 30 may be high and thus the refrigerant may show a tendency of being concentrated at the upper end of the second header 30. To prevent this unbalanced flow, at least one flow distribution baffle 80, 90 may be mounted to the second header 30 of the first heat exchanger 10.
[0092] In addition, the flow speed of the refrigerant rising up in the second header 30 may be low and thus the refrigerant may not be sufficiently supplied to the upper end of the second header 30. To prevent this unbalanced flow, at least one flow speed boosting baffle 100 may be mounted to the second header 30 of the first heat exchanger 10.
[0093] Thereby, even when the first heat exchanger 10 operates as the evaporator of the outdoor unit, the refrigerant is smoothly distributed. The unbalanced performance of the heat pump cooling and heating system in the cooing mode and the heating mode may be addressed.
[0094] As is apparent from the above description, a parallel flow type heat exchanger with vertical headers according to an embodiment of the present invention may ensure balanced distribution of a refrigerant from the headers to the tubes even when the heat exchanger operates as an evaporator of an outdoor unit. Thereby, degradation of heat exchange performance may not occur.
[0095] Therefore, when the parallel flow type heat exchanger with vertical headers is used in an outdoor unit of a heat pump type heating and cooling system, it may exhibit constant performance in both cooling and heating.
1. A heat exchanger comprising:
a plurality of tubes, each having first and second ends;
a first header disposed to communicate with the first end of each of the tubes;
a second header disposed to communicate with the second end of each of the tubes;
one or more flow passage defining baffles mounted to at least one of the first header and the second header to prevent flow of the refrigerant in the at least one header in a longitudinal direction and to divide the tubes into n groups (n ≥ 2, where n is an even number), each of the groups having tubes allowing the refrigerant to flow in one direction therethrough and the number of the one or more flow passage defining baffles being n-1; and
one or more flow distribution baffles mounted to at least one of the first header and the second header and arranged at one group of the n groups such that the one or more flow distribution baffles are positioned between the tubes belonging to the one group, each of the one or more flow distribution baffles being provided with at least one distribution hole allowing the refrigerant to pass therethrough.
2. The heat exchanger according to claim 1, wherein the flow distribution baffle positioned
between the tubes belonging to the last group of the n groups is arranged in a direction
of flow of the refrigerant when the heat exchanger operates as an evaporator.
3. The heat exchanger according to claim 1 or 2, wherein the distribution hole is spaced
from an inner side surface of the at least one header at an opposite side to the tubes
of the at least one header such that flow of the refrigerant along the inner side
surface at the opposite side is prevented.
4. The heat exchanger according to any one of the preceding claims, wherein a cross section
of each of the at least one distribution hole is a polygon, circle, or other closed
figure.
5. The heat exchanger according to any one of the preceding claims, wherein the at least
one distribution hole comprises either a hole formed in the flow distribution baffle
or a hole formed between the flow distribution baffle and an inner side surface of
the at least one header.
6. The heat exchanger according to any one of the preceding claims, wherein the total
cross-sectional area of the at least one distribution hole is 1 % to 40 % of the cross-sectional
area of an inner surface of the at least one header.
7. The heat exchanger according to any one of the preceding claims, wherein each of the
groups has 2 to 15 tubes.
8. The heat exchanger according to any one of the preceding claims, wherein n = 4, there
are three flow passage defining baffles and the tubes are divided into four groups.
9. The heat exchanger according to any one of the preceding claims, wherein:
the first header is provided with an inlet pipe and an outlet pipe; and
the flow distribution baffle is mounted to the second header.
10. The heat exchanger according to any one of the preceding claims, wherein:
the refrigerant flows upward in the first header and the second header when the heat exchanger operates as an evaporator; and
the refrigerant flows downward in the first header and the second header when the heat exchanger operates as a condenser.
11. The heat exchanger according to any one of the preceding claims, further comprising
one or more flow speed boosting baffles mounted to at least one header of the first
header and the second header arranged at an inlet of one group of the n groups such
that the flow speed boosting baffle is positioned between the one group and another
group positioned immediately ahead of the one group in a direction of flow of the
refrigerant when the heat exchanger operates as an evaporator, each of the one or
more flow speed boosting baffles being provided with at least one boosting hole allowing
the refrigerant to pass therethrough.
12. The heat exchanger according to claim 11, wherein the one or more flow speed boosting
baffles are positioned between the last group of the n groups arranged in the direction
of flow of the refrigerant and another group immediately ahead of the last group when
the heat exchanger operates as the evaporator.
13. The heat exchanger according to claim 11 or 12, wherein the cross section of each
of the one or more boosting holes is a polygon, circle, or other closed figure.
14. The heat exchanger according to claim 11, 12 or 13, wherein a total cross-sectional
area of the one or more boosting holes is 5 % to 70 % of a cross-sectional area of
an inner space of the at least one header.
15. The heat exchanger according to claim 11, 12, 13 or 14, wherein the total cross-sectional
area of the one or more boosting holes is greater than the total cross-sectional area
of the at least one distribution hole.