Heat exchange tube and heat exchanger having the heat exchange tube

Abstract

The utility model discloses a heat exchange tube and a heat exchanger having the heat exchange tube, the heat exchange tube includes a first sidewall and a second sidewall, the heat exchange tube further includes a separating member, one end of the separating member connects to the first sidewall, the other end of the separating member connects to the second sidewall, a plurality of the separating member is provided, a plurality of the separating member are spaced apart in a width direction of the heat exchange tube, the heat exchange tube further includes a first channel, the first channel exists between two adjacent separating members, n the first channels are provided, n the first channels are spaced apart in the width direction of the heat exchange tube, a width of the first channel is w, a height of the first channel is h, wherein 0.5<(w*h*n) / 12.2<0.6, by optimizing the design, the relationship between the heat exchange area of the heat exchange tube and the internal volume of the heat exchange tube can be balanced, product reliability is high.

Description

FIELD

[0001] The present invention relates to a heat exchange technology field, specifically relates to a heat exchange tube and a heat exchanger having the heat exchange tube.BACKGROUND

[0002] With requirements of users referring to heat exchange performance of a heat exchanger improved, a heat exchange tube as an important element of the heat exchanger has an important impact to the heat exchange performance of the heat exchanger, in the related technology, in order to improve heat exchange capacity of the heat exchanger, usually heat exchange area of the heat exchanger is increased, with regard to the heat exchange tube, the contact area between the heat exchange tube and a coolant can be increased, which can realize that the heat exchange area of the heat exchange tube is increased, but the heat exchange area of the heat exchange tube is increased, at the same time, the internal volume of the heat exchange tube also can be increased, how to balance the relationship between the heat exchange area of the heat exchange tube and the internal volume of the heat exchange tube, which has become a technical problem of persons skilled in the art concerned.SUMMARY

[0003] In view of this, in one aspect of the present invention, a heat exchange tube is proposed by optimizing the design, and can balance the relationship between the heat exchange area of the heat exchange tube and the internal volume of the heat exchange tube, product reliability is high.

[0004] An embodiment of the present invention provides a heat exchange tube, the heat exchange tube comprises a plurality of separating members, a plurality of the separating members are provided to be spaced apart in a width direction of the heat exchange tube, the heat exchange tube further comprises a plurality of first channels, the first channel exists between two adjacent separating members, the number of first channels is n, n the first channels are provided to be spaced apart in the width direction of the heat exchange tube, a width of the first channel is w, a height of the first channel is h, units of the width w and the height h are mm, wherein 0.5 < w * h * n / 12.2 < 0.6 .

[0005] In the embodiment of the present application, by setting the number of first channels of the heat exchange tube as n, setting the width of the first channel as w, setting the height of the first channel as h, and the relational expression of each parameter satisfies: 0.5<(w*h*n) / 12.2<0.6, therefore, by optimizing the design, under satisfying the requirements of the heat exchange performance, by optimizing the number of first channels as well as the height and the width of the first channel, the heat exchange tube can balance the relationship between the heat exchange area of the heat exchange tube and the internal volume of the heat exchange tube, product reliability is high.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Fig. 1 is a schematic structural diagram of a heat exchange tube according to an embodiment of the present invention; Fig. 2 is a sectional diagram in E-E direction of the heat exchange tube shown in Fig. 1; Fig. 3 is a schematic diagram of the front view of the heat exchange tube shown in Fig. 1; Fig. 4 is a schematic structural diagram of a heat exchanger according to an embodiment of the present invention; Fig. 5 is an enlarged diagram of D part of the heat exchanger 1 shown in Fig. 4; Fig. 6 is a schematic diagram of the front view of the heat exchanger shown in Fig. 4; Fig. 7 is a schematic structural diagram of the heat exchanger shown in Fig. 4 after it has been bent; Fig. 8 is a schematic structural diagram of a heat exchanger according to a yet further embodiment of the present invention; Fig. 9 is a schematic structural diagram of a heat exchanger according to a still yet further embodiment of the present invention. Reference signs:

[0007] Heat exchanger 100, heat exchange tube 10, first channel 101, first sidewall 102, second sidewall 103, third sidewall 104, fourth sidewall 105, separating member 106, first sub-wall 1061, second sub-wall 1062, main body part 107, first part 108, first tube 20, third cavity 201, fourth cavity 202, fifth cavity 203, second tube 30, sixth cavity 301, seventh cavity 302, first connection tube 40, second connection tube 50, first member 60.DETAILED DESCRIPTION

[0008] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in drawings. Embodiments described below with reference to drawings are exemplary and are intended to be used to explain the present invention and are not to be construed as a limitation of the present invention. In the descriptions of the present invention, it is to be understood that the terms "center", "longitudinal", "transverse", "length ", "width", "thickness", "on", "below", "front", "rear", "left', "right", "vertical", "horizontal", "top", "bottom", "inside", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientation or positional relationships based on those shown in drawings, just intend to facilitate to describe the present invention and simplify the descriptions, and do not indicate or imply that the device or elemental fixture referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it is not construed as a limitation of the present invention.

[0009] As shown in Fig. 1 to Fig. 3, a heat exchange tube 10 according to an embodiment of the present invention has a flat cross section shape, the heat exchange tube 10 comprises a plurality of separating members 106, a plurality of separating members 106 are provided to be spaced apart in a width direction of the heat exchange tube 10, an inner cavity of the heat exchange tube 10 is divided to define n first channels 101 by a plurality of separating members 106, n first channels 101 are provided to be spaced apart in the width direction of the heat exchange tube 10, the first channel 101 exists between two adjacent separating members 106, it is noted that, as shown in Fig. 1, the width direction of the heat exchange tube 10 is the A-A direction illustrated, the length direction of the heat exchange tube 10 is the B-B direction illustrated, the thickness direction of the heat exchange tube 10 is the C-C direction illustrated, i.e., a plurality of first channels 101 are spaced apart in the A-A direction of the heat exchange tube 10, first channels 101 are available for the refrigerant to flow inside the heat exchange tube 10 to facilitate heat exchange with outside air, a width of the first channel 101 is w, a height of the first channel 101 is h, units of the width w and the height h are mm, wherein 0.5<(w*h*n) / 12.2<0.6,

[0010] The heat exchange tube 10 according to the embodiment of the present invention, by optimizing the design of the heat exchange tube 10 and setting parameters to 0.5<(w*h*n) / 12.2<0.6, is beneficial to balance the relationship between the internal volume of the heat exchange tube and the heat exchange area of the heat exchange tube, product reliability is high.

[0011] In some embodiments, specifically, the heat exchange tube 10 is shown in Fig. 1 and Fig. 2, the heat exchange tube 10 has a first part 108 and a main body part 107, a width of the first part 108 is less than a width of the main body part 107, both ends of the main body part 107 have the first part 108, an outer perimeter of the main body part 107 is more than an outer perimeter of the first part 108, the separating member 106 comprises a first sub-wall 1061 and a second sub-wall 1062, the main body part 107 has a first cavity, the first part 108 has a second cavity, the first sub-wall 1061 is located in the first cavity of the main body part 107, the second sub-wall 1062 is located in the second cavity, a plurality of second sub-walls are spaced apart in the width direction of the heat exchange tube 10, the thickness of at least one wall of the first sub-wall 1061 and the second sub-wall 1062 is t, a unit of the wall thickness t is mm, wherein 0.2<(25-2t) / (n*l)<0.9, by optimizing the design of the heat exchange tube 10, parameters of the second sub-wall 1062 of the heat exchange tube 10 are in the range of 0.2<(25-2t) / (n*l)<0.9, which is beneficial to reduce the internal volume of the heat exchange tube, beneficial to improve the pressure resistant performance of the heat exchange tube 10, beneficial to control the cost of the material, when the range of parameters of the second sub-wall 1062 of the heat exchange tube 10 is less than 0.2, which is easy to cause the pressure resistant performance of the heat exchanger tube 10 to be insufficient, when the range of parameters of the second sub-wall 1062 of the heat exchange tube 10 is more than 0.9, which increases the material cost of a heat tube of the heat exchange tube 10, therefore, when the wall thickness of the second sub-wall 1062 and / or the first sub-wall 1061 is in the range of 0.2<(25-2t) / (n*l) <0.9, an optimal relationship between the heat exchange area of the heat exchange tube 10 and the internal volume of the heat exchange tube 10 can be realized, thus some requirements of the heat exchange performance of the heat exchange tube 10 and the internal volume of the heat exchange tube 10 are satisfied.

[0012] In some embodiments, specifically, as shown in Fig. 3, the cross section of the heat exchange tube 10 is a roughly elliptical structure, the heat exchange tube 10 comprises a first sidewall 102 and a second sidewall 103 in the thickness direction (C-C direction) of the heat exchange tube 10, the heat exchange tube 10 further comprises a third sidewall 104 and a fourth sidewall 105 in the width direction (A-A direction) of the heat exchange tube 10, one end of the first sidewall 102 connects to one end of the third sidewall, the other end of the third sidewall connects to one end of the second sidewall 103, the other end of the second sidewall 103 connects to one end of the fourth sidewall 105, the other end of the fourth sidewall connects to the other end of the first sidewall 102, a thickness of at least one sidewall of the third sidewall 104 and the fourth sidewall 105 is y, wherein a unit of wall thickness y is mm, wherein 0.4<y< 0.7, when wall thicknesses y of the third sidewall 104 and the fourth sidewall 105 are in the range of 0.4 to 0.7, which is beneficial to balance the relationship between the internal volume of the heat exchange tube 10 and the heat exchange area of the heat exchange tube 10, and product reliability is high.

[0013] In some embodiments, specifically, as shown in Fig. 3, the heat exchange tube 10 is a flat tube, a difference between the width and the height of the first channel 101 of the heat exchange tube 10 is between 0.2 and 0.32, wherein units of the width w and the height h of the first channel 101 of the heat exchange tube are mm, in the parameter range, which is beneficial to balance the relationship between both the internal volume of the heat exchange tube 10 and the heat exchange area of the heat exchange tube 10, and product reliability is high.

[0014] In some embodiments, specifically, as shown in Fig. 3, the height h of the first channel 101 satisfies the following condition: 0.36<h<0.6. In the parameter range, it is beneficial to balance the relationship between both the internal volume of the heat exchange tube 10 and the heat exchange area of the heat exchange tube 10, and the product reliability is high.

[0015] In some embodiments, specifically, as shown in Fig. 3, the width w of the first channel 101 satisfies the following condition, wherein a unit of the width w is mm, 0.79<w<1.03. In the parameter range, it is beneficial to balance the relationship between both the internal volume of the heat exchange tube 10 and the heat exchange area of the heat exchange tube 10, and the product reliability is high.

[0016] A heat exchanger 100 according to an embodiment of the present invention, specifically, as shown in Fig. 4 to Fig. 8, the heat exchanger 100 comprises a first tube 20 and a second tube 30, the first tube 20 comprises a first tube body, the second tube 30 comprises a second tube body, the first tube body has a second channel, and the second tube body has a third channel, the heat exchanger 100 further comprises a plurality of heat exchange tubes 10, one end of the heat exchange tube 10 connects to the first tube 20, the other end of the heat exchange tube 10 connects to the second tube 30, a plurality of heat exchange tubes 10 are spaced apart in a length direction of the first tube 20 or the second tube 30, the heat exchange tube 10 comprises a plurality of first channels 101, a plurality of first channels 101 are spaced apart in a width direction (A-A direction) of the heat exchange tube 10.

[0017] The heat exchange tube 10 comprises a main body part 107 and a first part 108, in some designs, the first part can be a necking part, the heat exchange tube is shown in Fig. 1 to Fig. 2, both ends of the main body part 107 connect to the first part 108, when one end of the heat exchange tube 10 connects to the first tube 20, the other end of the heat exchange tube 10 connects to the second tube 30, therefore, one of two first parts 108 is located in the first tube 20, and the other first part 108 is located in the second tube 30, providing the first parts 108, on the one hand, is beneficial to improve the connection strength between the heat exchange tubes 10 and the first tube 20 / the second tube 30, on the other hand, is beneficial to control the insertion depth of the heat exchange tube 10 into the first tube 20 / second tube 30, since the sizes of slot openings on the first tube 20 / second tube 30 are matched with the sizes of first parts 108.

[0018] The heat exchanger 100 further comprises a first connection tube 40 and a second connection tube 50, under normal conditions, one tube of the first connection tube 40 and the second connection tube 50 is a refrigerant inlet tube and the other is a refrigerant outlet tube, in some designs, the first connection tube 40 connects to the first tube 20, the second connection tube 50 connects to the first tube 20, also the second connection tube 50 can connect to the second tube 30, and the first connection tube 40 can connect to the second tube 30, and two connection tubes are provided at the same side of the heat exchanger 100, which is beneficial to reduce packaging costs.

[0019] Specifically, as shown in Fig. 4 to Fig. 8, the flow cross section area of the second channel is S2, the flow cross section area of the third channel is S2, the flow cross section area of two channels is the same, in the cross section of the heat exchange tube 10, a sum of the flow cross section area of a plurality of the first channels 101 is S1, a length of the main body part 107 of the heat exchange tube 10 is L, a height of the second tube 30 is H, units of the length L of the main body part and the height H are mm, wherein 4<(S1*L*6+S2*H) / (7.33*L+12*H)<8, it is beneficial to balance the relationship between both the internal volume of the heat exchanger 100 and the heat exchange area of the heat exchanger 100, and the product reliability is high.

[0020] In some embodiments, the length of the first tube 20 of the heat exchanger 100 and the length of the second tube 30 of the heat exchanger 100 may not be same, specifically, as shown in Fig. 6, the length of the first tube 20 of the heat exchanger 100 and the length of the second tube 30 of the heat exchanger 100 are not same, the length of the second tube 30 is less than the length of the first tube 20, therefore, the H in 4<(S1*L*6+S2*H) / (7.33*L+12*H)<8 is defined a dimension length of a relatively shorter tube in the first tube 20 and the second tube 30, in addition, as shown in Fig. 9, there is also a design that the length of the first tube 20 of the heat exchanger 100 and the length of the second tube 30 of the heat exchanger 100 are same, therefore, since the length of the two tubes is same, choosing the length of any tube is acceptable.

[0021] Specifically, as shown in Fig. 4 to Fig. 6, the length of the first tube 20 is more than the length of the second tube 30, the first connection tube 40 is mounted in the length range of the first tube exceeding the second tube, therefore, compared to an usual heat exchanger, by providing the connection tube in the length range of the first tube exceeding the second tube , and by connecting the connection tube to the tube wall of the first tube 20, it is beneficial to improve the pressure resistant strength of the first connection tube, beneficial to improve the corrosion resistance performance of the first connection tube .

[0022] In some embodiments, as shown in Fig. 5, a radius of the second tube 30 is R. under normal conditions, a radius of the first tube 20 and the radius of the second tube 30 are same, thus, when the radius of at least one tube of the first tube 20 and the second tube 30 satisfies 3<π*R 2< / 12<10. In satisfying the above ranges, on the one hand, it is beneficial to improve the flow speed of the refrigerant, on the other hand, it is beneficial to enhance pressure resistance performance of the heat exchanger 100. If the radius of at least one tube of the first tube 20 and the second tube 30 is less than 3, a flow speed of refrigerant in the first tube 20 and the second tube 30 is too fast, the heat exchange performance is affected, if the radius of at least one tube of the first tube 20 and the second tube 30 is more than 10, the internal volume of the first tube 20 and the second tube 30 is too small, heat exchange capacity is insufficient and pressure resistance performance is insufficient.

[0023] In some embodiments, the heat exchanger 100 is shown in Fig. 6 to Fig. 8, in some applications, the heat exchanger 100 can be used as a condenser, in some applications, as shown in Fig. 7, the heat exchanger 100 after bent can be used to wrap some metal tanks for heating liquid (such as water) inside metal tanks, under normal conditions, a distance between adjacent heat exchange tubes 10 is equal, but the distance between some adjacent heat exchange tubes 10 in some heat exchangers 100 is more than the width of one heat exchange tube 10, in order to realize partly enhanced heat exchange, save cost and save energy.

[0024] In some embodiments, the heat exchanger 100 is shown in Fig. 8 and Fig. 9, the heat exchanger 100 further comprises a first member 60, the first member 60 connects to the side wall of the heat exchange tubes 10 for fixing the position of the heat exchange tubes 10 to reduce the offset of the heat exchange tubes 10, in some designs, the first member 60 can be foam, can be an rubber strip, also can be an aluminum plate, the first member 60 is fixedly connected to a plurality of heat exchange tubes 10 by means of pasting or welding, thereby the reliability of the heat exchanger 100 is enhanced.

[0025] In some embodiments, as shown in Fig. 8 and Fig. 9, the first channel 101 of the first tube 20 is divided into a plurality of cavities, the second channel of the second tube 30 is divided into a plurality of cavities, specifically, the first tube 20 comprises a third cavity 201, a fourth cavity and a fifth cavity 203, the second tube 30 comprises a sixth cavity 301 and a seventh cavity 302, the third cavity 201 is in communication with the inner cavity of the first connection tube 40 , the fifth cavity 203 is in communication with the inner cavity of the second connection tube 50, the fourth cavity exists between the third cavity 201 and the fifth cavity 203, the heat exchanger 100 comprises a first connection tube 40 and a second connection tube 50, the first connection tube 40 connects to the first tube 20, the second connection tube 50 connects to the first tube 20.

[0026] A plurality of heat exchange tubes 10 comprise a first set of heat exchange tubes 10, a second set of heat exchange tubes 10, a third set of heat exchange tubes 10 and a fourth set of heat exchange tubes 10, a plurality of first channels 101 of the first set of heat exchange tubes 10 are in communication with the third cavity 201 and the sixth cavity 301, a plurality of first channels 101 of the second set of heat exchange tubes 10 are in communication with the fourth cavity and the sixth cavity 301, a plurality of first channels 101 of the third set of heat exchange tubes 10 are in communication with the fourth cavity and the seventh cavity 302, a plurality of first channels 101 of the fourth set of heat exchange tubes 10 are in communication with the seventh cavity 302 and the fifth cavity 203.

[0027] In some embodiments, specifically, as shown in Fig. 8, the heat exchanger 100 comprises a plurality of heat exchange tubes 10, a plurality of heat exchange tubes 10 can divide into a first set of heat exchange tubes 10, a second set of heat exchange tubes 10, a third set of heat exchange tubes 10 and a fourth set of heat exchange tubes 10, the total number of the fourth set of heat exchange tubes 10 is less than the number of the first set of heat exchange tubes 10, since the heat exchange tubes 10 are used in a condensational process, the refrigerant changes from the high temperature high pressure gas to relatively low temperature low pressure gas, thus the number of the fourth set of heat exchange tubes 10 is reduced, it is beneficial to reduce the cost of the heat exchanger 100.

[0028] In the descriptions of the present description, descriptions with reference to the terms such as "an embodiment", "some embodiments", "examples", "a specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In the present description, schematic expressions of the above terms are not necessary referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. Furthermore, without contradicting each other, persons skilled in the art can combine and unite different embodiments or examples and features of different embodiments or examples described in the present description.

[0029] In the present application, unless otherwise expressly specified or limited, the terms "mounted", "interconnection", "connected", "fixed" and the like shall be broadly understood, for example, a fixed connection, a removable connection, or an integral connection; a mechanical connection, an electrical connection, or a communication with each other; a direct connection or an indirect connection via intermediate media; and a connectivity within the two elements or an interactive relationship between the two elements, unless otherwise expressly limited. For persons skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific situation.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and can not be understood as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with the terms "first", "second" can expressly or impliedly include at least one such feature. In the descriptions of the present application, "plurality" means at least two, e.g., two, three, etc., unless otherwise expressly and specifically limited.

[0031] In the present application, unless otherwise expressly specified and limited, a first feature "on" or "below" a second feature can be a direct contact between the first and second features, or an indirect contact between the first and second features via intermediate media. Moreover, the first feature being "on", "above" and "on the top" the second feature can be that the first feature is right or obliquely "on," "above," or "on top of" the second feature, or just means that the first feature is at a height higher than the second feature. The first feature is "below", "under" and "on bottom of" the second feature can be that the first feature is right or obliquely "below," "under," or "on bottom of" the second feature, or just means that the first feature is at a height lower than the second feature.

[0032] Although embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and can not be construed as a limitation of the present invention, and persons skilled in the art can make changes, modifications, substitutions, and variations of the above embodiments within the scope of the present invention.

Claims

1. A heat exchange tube, comprising: a first sidewall and a second sidewall, a separating member, wherein one end of the separating member connects to the first sidewall, the other end of the separating member connects to the second sidewall, a plurality of separating members are provided, a plurality of the separating members are spaced apart in a width direction of the heat exchange tube, the heat exchange tube further comprises a first channel, there is the first channel between two adjacent the separating members, n the first channels are provided, n the first channels are spaced apart in the width direction of the heat exchange tube, a width of the first channel is w, a height of the first channel is h, units of the width w and the height h are mm, wherein 0.5<(w*h*n) / 12.2<0.6.

2. The heat exchange tube according to claim 1, wherein the heat exchange tube comprises a first part and a main body part, a width of the first part is less than a width of the main body part, at least one end of the main body part has the first part, the separating member comprises a first sub-wall and a second sub-wall, the main body part has a first cavity, the first sub-wall is located in the first cavity, the first part has a second cavity, the second sub-wall is located in the second cavity, a thickness of at least one of the first sub-wall and the second sub-wall is t, a unit of the thickness t is mm, wherein 0.2<(25-2t) / (n*l)<0.9.

3. The heat exchange tube according to claim 1 or claim 2, wherein the heat exchange tube comprises a third sidewall and a fourth sidewall in the width direction of the heat exchange tube, one end of the first sidewall connects to one end of the third sidewall, the other end of the first sidewall connects to one end of the fourth sidewall, one end of the second sidewall connects to the other end of the third sidewall, the other end of the second sidewall connects to the other end of the fourth sidewall, a thickness of at least one sidewall of the third sidewall and the fourth sidewall is y, a unit of wall thickness y is mm, wherein 0.4<y<0.7.

4. The heat exchange tube according to claim 1 or claim 2, wherein the heat exchange tube is a flat tube, the heat exchange tube satisfies the following condition: 0.2<w-h<0.32.

5. The heat exchange tube according to claim 1 or claim 2, wherein the height h of the first channel satisfies the following condition: 0.36<h<0.6.

6. The heat exchange tube according to claim 1 or claim 2, wherein the width w of the first channel satisfies the following condition: 0.79<w<1.03.

7. A heat exchanger, comprising: a first tube and a second tube, wherein one tube of the first tube and the second tube comprises a tube body, the tube body comprises tube wall, the tube body has a second channel, flow cross-sectional area of the second channel is S2; a heat exchange tube, wherein one end of the heat exchange tube connects to the first tube, the other end of the heat exchange tube connects the second tube, a plurality of the heat exchange tubes are provided, a plurality of the heat exchange tubes are spaced apart in a length direction of the first tube or the second tube, the heat exchange tube comprises a plurality of first channels, the plurality of first channels are spaced apart in a width direction of the heat exchange tube, a sum of the flow cross-sectional area of a plurality of the first channels in the cross section of the heat exchange tube is S1; wherein the heat exchange tube comprises a main body part and a first part, at least one end of the main body part has the first part, the main body part connects to the first part, the first part is located in the tube body, a length of the main body part is L, a height of the second tube is H, units of the length L of the main body part and the height H of the second tube are mm, wherein 4 < S 1 * L * 6 + S 2 * H / 7.33 * L + 12 * H < 8 .

8. The heat exchanger according to claim 7, wherein a radius of at least one tube of the first tube and the second tube is R, a unit of the radius R is mm, wherein 3<π*R2 / 12<10.

9. The heat exchanger according to claim 7 or claim 8, wherein a width of the main body part of the heat exchange tube is W, the distance between at least one of the heat exchange tubes and an adjacent the heat exchange tube is more than W in the width direction of the heat exchange tube.

10. The heat exchanger according to claim 7 or claim 8, wherein the first tube comprises a third cavity, a fourth cavity and a fifth cavity, the second tube comprises a sixth cavity and a seventh cavity, the fourth cavity exists between the third cavity and the fifth cavity; wherein a plurality of the heat exchange tubes comprise a first set of heat exchange tubes, a second set of heat exchange tubes, a third set of heat exchange tubes and a fourth set of heat exchange tubes, a plurality of the first channels of the first set of heat exchange tubes are in communication with the third cavity and the sixth cavity, a plurality of the first channels of the second set of heat exchange tubes are in communication with the fourth cavity and the sixth cavity, a plurality of the first channels of the third set of heat exchange tubes are in communication with the fourth cavity and the seventh cavity, a plurality of the first channels of the fourth set of heat exchange tubes are in communication with the seventh cavity and the fifth cavity.

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