Microchannel heat exchanger and heat pump system having the same

Abstract

The present invention provides a microchannel heat exchanger and a heat pump system having the same, wherein the microchannel heat exchanger comprises: a manifold (1) and an inner insert (2), wherein the inner insert (2) is inserted into the inner cavity (10) of the manifold and can introduce a fluid into the inner cavity of the manifold (1) or guide the fluid in the inner cavity of the manifold (1) out through the inner insert (2), and the portion of the inner insert (2) extending into the inner cavity is bent and extends upward, and the free end of the inner insert (2) or the pipe section near the free end is formed into a tapered pipe section (21), so that the tapered pipe section (21) is formed into a pipe section with a gradually decreasing cross-sectional area from bottom to top, and a plurality of injection holes (22) are provided on the free end. According to the present invention, the flow velocity of the refrigerant can be effectively increased, the degree of mixing of the refrigerant after being ejected from the injection hole can be increased, and the phenomenon that the gas-liquid two-phase refrigerant is easily stratified can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchange, and in particular to a microchannel heat exchanger and a heat pump system having the same. Background Art

[0002] Microchannel heat exchanger is a new type of high-efficiency heat exchanger with the advantages of high heat transfer efficiency, small size, light weight, and small filling volume. When the microchannel heat exchanger is used as an evaporator, the inlet is generally gas-liquid two-phase, and the manifold of the traditional microchannel heat exchanger has no diversion measures. After entering the manifold, the gas-liquid two-phase stratification phenomenon is obvious, resulting in uneven distribution of the refrigerant entering the flat tube and poor heat exchange performance of the heat exchanger.

[0003] Patent CN203798032U provides a microchannel heat exchanger with a header and an inner tube with uniform flow holes, and multiple partition plates are set to evenly flow the refrigerant flowing out of the flow holes of the inner tube into the space formed between the partition plates, which is used to improve the uniformity of refrigerant distribution and the heat exchange efficiency of the heat exchanger. However, the inner tube structure of this solution is a straight circular tube. Although it can improve the diversion effect of the imported gas-liquid two-phase refrigerant, the outlet refrigerant is still likely to be stratified.

[0004] When the microchannel heat exchanger in the prior art is used as an evaporator, the inlet is generally gas-liquid two-phase, and the gas-liquid two-phase stratification phenomenon is obvious after entering the collecting pipe, resulting in uneven distribution of the refrigerant entering the flat tube and poor heat exchange performance of the heat exchanger. Therefore, the present invention studies and designs a microchannel heat exchanger and a heat pump system having the same. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the prior art that the gas-liquid two-phase stratification phenomenon is obvious after the inlet of the microchannel heat exchanger enters the collecting pipe, resulting in uneven distribution of the refrigerant entering the flat tube and poor heat exchange performance of the heat exchanger, thereby providing a microchannel heat exchanger and a heat pump system having the same.

[0006] In order to solve the above problems, the present invention provides a microchannel heat exchanger, which comprises:

[0007] A collecting pipe and an inner tube, wherein the inner tube is inserted into the inner cavity of the collecting pipe and can introduce fluid into the inner cavity of the collecting pipe or discharge the fluid in the inner cavity of the collecting pipe through the inner tube, and the part of the inner tube extending into the inner cavity is bent and extends upward, and the free end of the inner tube or the pipe section near the free end is formed as a tapered pipe section, so that the tapered pipe section is formed into a pipe section with a gradually decreasing cross-sectional area from bottom to top, and a plurality of injection holes are arranged on the free end.

[0008] Preferably,

[0009] The free end is the first straight pipe section, and the plurality of injection holes are provided on the peripheral wall of the first straight pipe section and are connected to the interior thereof. At least one injection hole is also provided on the top of the first straight pipe section. The upper end of the tapered pipe section is connected to the first straight pipe section, the two are internally connected, and / or the tapered pipe section is a nozzle with a smooth curved transition on the outer wall.

[0010] Preferably,

[0011] The collecting pipe extends in a vertical direction and includes a plurality of inner chambers, and the plurality of inner chambers are arranged in sequence up and down. At least one partition is provided inside the collecting pipe, and adjacent inner chambers are separated by the partition.

[0012] Preferably,

[0013] An inner cannula is arranged in each inner cavity.

[0014] Preferably,

[0015] The inner insert tube also includes a second straight pipe section, which is arranged at the lower end of the tapered pipe section and communicated with the interior of the tapered pipe section.

[0016] Preferably,

[0017] The second straight pipe section is longer than the first straight pipe section.

[0018] Preferably,

[0019] The inner insert pipe also includes an outer pipe section located outside the collecting pipe, one end of the outer pipe section is connected to the second straight pipe section, and the other end of the outer pipe section can also be connected to the diverter.

[0020] Preferably,

[0021] It also includes at least one flat tube, one end of which is inserted into the inner cavity of the collecting tube and communicated with the inner cavity, and at least two flat tubes are correspondingly arranged in each inner cavity, and there is a preset distance between adjacent flat tubes.

[0022] Preferably,

[0023] It also includes a second header, the other end of the flat tube is inserted into the second header, and the second header is also connected to an air intake pipe.

[0024] The present invention also provides a heat pump system, which includes the microchannel heat exchanger described in any of the preceding items, and also includes a compressor, a throttling device and a second heat exchanger, wherein the compressor, the second heat exchanger, the throttling device and the microchannel heat exchanger are connected in sequence.

[0025] The microchannel heat exchanger and the heat pump system having the same provided by the present invention have the following beneficial effects:

[0026] The present invention inserts an inner tube into the inner cavity of the collecting tube, and the free end of the inner tube or the tube section near the free end is formed into a tapered tube section with a gradually decreasing cross-sectional area from bottom to top. The tapered tube section cross-section can effectively increase the flow velocity of the refrigerant, thereby increasing the degree of mixing of the refrigerant after being sprayed out of the injection hole, and the injection effect is better. The refrigerant coming out of the tapered tube is small mist droplets, which helps to improve the phenomenon that the gas-liquid two-phase refrigerant is easy to stratify, so that the two-phase refrigerant entering the flat tube can be distributed more evenly, effectively improving the heat exchange performance in the flat tube and improving the heat exchange effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the microchannel heat exchanger of the present invention;

[0028] Figure 2 for Figure 1 A partial enlarged structural diagram of part A;

[0029] Figure 3 It is a three-dimensional structural diagram of the inner tube in the microchannel heat exchanger of the present invention;

[0030] Figure 4 for Figure 3 A partial enlarged structural diagram of part B;

[0031] Figure 5 It is a system cycle diagram of the heat pump system with a microchannel heat exchanger of the present invention.

[0032] The reference numerals are as follows:

[0033] 1. Manifold; 10. Inner cavity; 11. Partition; 2. Inner insert; 21. Tapered pipe section; 22. Injection hole; 23. First straight pipe section; 24. Second straight pipe section; 25. Outer pipe section; 3. Flat tube; 4. Second manifold; 5. Inlet pipe; 6. Diverter; 7. Compressor; 8. Throttling device; 9. Second heat exchanger; 100. Microchannel heat exchanger; 200. Four-way valve. DETAILED DESCRIPTION

[0034] like Figure 1-5 As shown, the present invention provides a microchannel heat exchanger, which includes:

[0035] A collecting pipe 1 and an inner tube 2, wherein the inner tube 2 is inserted into the inner cavity 10 of the collecting pipe and can introduce fluid into the inner cavity of the collecting pipe 1 or discharge the fluid in the inner cavity of the collecting pipe 1 through the inner tube 2, and the part of the inner tube 2 extending into the inner cavity is bent and extends upward, and the free end of the inner tube 2 or the pipe section near the free end is formed as a tapered pipe section 21, so that the tapered pipe section 21 is formed into a pipe section with a gradually decreasing cross-sectional area from bottom to top, and a plurality of injection holes 22 are arranged on the free end.

[0036] The present invention inserts an inner tube into the inner cavity of the collecting tube, and the free end of the inner tube or the tube section near the free end is formed into a tapered tube section with a gradually decreasing cross-sectional area from bottom to top. The tapered tube section cross-section can effectively increase the flow velocity of the refrigerant, thereby increasing the degree of mixing of the refrigerant after being sprayed out of the injection hole, and the injection effect is better. The refrigerant coming out of the tapered tube is small mist droplets, which helps to improve the phenomenon that the gas-liquid two-phase refrigerant is easy to stratify, so that the two-phase refrigerant entering the flat tube can be distributed more evenly, effectively improving the heat exchange performance in the flat tube and improving the heat exchange effect.

[0037] Preferably,

[0038] The free end is the first straight pipe section 23, and the plurality of injection holes 22 are provided on the peripheral wall of the first straight pipe section 23 and are connected to the interior thereof. At the same time, at least one injection hole 22 is also provided on the top of the first straight pipe section 23; the upper end of the tapered pipe section 21 is connected to the first straight pipe section 23, the two are connected to the interior thereof, and / or the tapered pipe section 21 is a nozzle with a smooth curved surface transition on the outer wall. This is the preferred structural form of the tapered pipe section of the present invention, that is, it is provided at the portion where the free ends are connected, the free ends are used to provide injection holes to spray the refrigerant into the inner cavity of the manifold, and the tapered pipe section is a nozzle with a smooth curved surface transition, which can effectively accelerate the refrigerant, and the speed is gradually increased, which can effectively enhance the mixing between the gas-liquid two-phase refrigerant.

[0039] Preferably,

[0040] The manifold 1 extends in the vertical direction and includes a plurality of inner chambers 10, and the plurality of inner chambers 10 are arranged in sequence up and down, and at least one partition 11 is provided inside the manifold 1, and adjacent inner chambers 10 are separated by the partition 11. This is the preferred structural form of the plurality of inner chambers of the manifold of the present invention, and the plurality of inner chambers can be effectively formed by the arrangement of the plurality of partitions, and the manifold extends in the vertical direction so that the inner chambers are arranged in sequence in the up and down directions, and the outlet free end of the inner insert tube is arranged upward so that the ejected refrigerant can be ejected upward, further effectively mixing the gas-liquid two-phase, and preventing the liquid phase refrigerant from being deposited below due to its high density when ejected downward, thereby further improving the uniformity of the two-phase mixing.

[0041] Preferably,

[0042] An inner insert tube 2 is disposed in each inner cavity 10. This is a further preferred structural form of the present invention, that is, each inner cavity is correspondingly provided with an inner insert tube, which can effectively introduce fluid into each inner cavity, or can drain refrigerant from each inner cavity.

[0043] Preferably,

[0044] The inner insert tube 2 further includes a second straight tube section 24, which is disposed at the lower end of the tapered tube section 21 and communicates with the interior of the tapered tube section 21. This is a further preferred structural form of the inner insert tube of the present invention, and the tapered tube section can be connected and effectively communicated with the outside through the second straight tube section, and the fluid is conducted and the refrigerant at the bottom is directed upward to the upper end and sprayed out, thereby improving the uniform mixing degree of the gas-liquid two-phase refrigerant.

[0045] Preferably, the length of the second straight pipe section 24 is greater than that of the first straight pipe section 23. The second straight pipe section is mainly used for conducting the fluid and guiding the refrigerant at the bottom upward to the upper end and spraying it out, and the first straight pipe section is mainly used for discharging the refrigerant. The relationship between the two is set as above to enhance the upward conduction effect.

[0046] Preferably, the inner insert tube 2 further comprises an outer tube section 25 located outside the manifold 1, one end of the outer tube section 25 is connected to the second straight tube section 24, and the other end can also be connected to the diverter 6. This is a further preferred structural form of the inner insert tube of the present invention, and the external refrigerant can be conducted to the second straight tube section through the outer tube section.

[0047] Preferably,

[0048] It also includes at least one flat tube 3, one end of which is inserted into the inner cavity 10 of the header 1 and communicated with the inner cavity 10, and at least two flat tubes 3 are correspondingly arranged in each inner cavity 10, and there is a preset distance between adjacent flat tubes 3. The flat tube and at least two flat tubes communicated with the inner cavity can effectively guide the refrigerant in the header to the inside of the flat tube, thereby completing the heat exchange on the flat tube.

[0049] Preferably, a second header 4 is further included, the other end of the flat tube 3 is inserted into the second header 4, and the second header 4 is also connected to an air intake pipe 5. The second header can effectively connect the other end of the flat tube to guide the refrigerant after heat exchange in the flat tube to the second header and discharge it, or guide the external refrigerant to the flat tube through the second header for heat exchange.

[0050] The present invention also provides a heat pump system, which includes the microchannel heat exchanger 100 described in any of the preceding items, and also includes a compressor 7, a throttling device 8 and a second heat exchanger 9, wherein the compressor 7, the second heat exchanger 9, the throttling device 8 and the microchannel heat exchanger 100 are connected in sequence.

[0051] The microchannel heat exchanger of the present invention adopts the form of inserting tapered tubes in the manifold, which can increase the flow rate of the refrigerant. The refrigerant coming out of the inserting tapered tube and entering each manifold cavity is a mist-like small droplet, which improves the stratification of the gas-liquid two-phase refrigerant in the manifold, is conducive to uniform flow distribution, and improves the heat exchange performance of the heat exchanger. Compared with the ordinary round straight insert copper tube, the use of the inserting tube in the tapered tube section increases the flow rate of the refrigerant in the tube, has a better injection effect, and the refrigerant outlet is a mist, and the speed is relatively large, which is conducive to uniform flow distribution.

[0052] Figure 1 The microchannel heat exchanger of the present invention is a schematic diagram of the structure. The microchannel heat exchanger of the present invention mainly includes an inner tube 2 with a tapered tube section 21, a flat tube 3, a left header (a second header 4), an inlet / outlet pipe (an inlet pipe 5), a partition 11 and a right header (a header 1). The header 1 is divided into N cavities, each of which contains an inner tube 2, and the refrigerant is divided into N paths from the splitter to flow to each cavity.

[0053] Figure 2 The schematic diagram of the internal structure of a cavity of the right manifold of the microchannel heat exchanger of the present invention is shown in FIG. When the heat exchanger is used as an evaporator, the gas-liquid two-phase refrigerant enters the microchannel heat exchanger through the L-shaped inner tube 2, and the refrigerant first flows through a long straight pipe section, then through the tapered pipe section 21, and finally through the outer periphery of the first straight pipe section 23 and the injection hole 22 (small hole) opened at the top, and is sprayed into the cavity (inner cavity 10) of the right manifold in the form of mist droplets. The flow velocity of the gas-liquid two-phase refrigerant increases after passing through the tapered pipe section 21. The refrigerant flow velocity is relatively large, and the pressure of the tapered pipe section 21 is also relatively large (since the top end is approximately closed, the refrigerant accelerated through the tapered pipe can reach a very high pressure at the outlet of the tapered pipe due to high-speed movement, which is more conducive to the conversion of the refrigerant from gas phase to liquid phase), which is beneficial to the conversion of the gas phase in the gas-liquid two-phase refrigerant to the liquid phase, thereby reducing the dryness of the two-phase refrigerant. Finally, the refrigerant is ejected from the small hole of the tapered pipe (injection hole 22) in the form of small mist droplets, which helps to improve the uneven diversion phenomenon caused by the easy stratification of the gas-liquid two-phase refrigerant inside the collecting pipe cavity.

[0054] Figure 3-4 The structure diagram of the microchannel heat exchanger with an internally inserted reducer of the present invention is shown. Small holes are provided in the straight opening section and the top opening section of the reducer, and the refrigerant is finally sprayed out in the form of mist droplets through the small holes.

[0055] Figure 5The heat pump system of the microchannel heat exchanger of the present invention comprises a microchannel heat exchanger 100, a throttling device 8, a second heat exchanger 9, a four-way valve 200, a compressor 7, and a diverter 6, and the above components are interconnected through pipelines.

[0056] When the microchannel heat exchanger is used as a condenser, a and b of the four-way valve 200 are connected, and c and d are connected. The refrigerant discharged from the compressor 7 passes through the four-way valve 200, and then enters the microchannel heat exchanger 100 for condensation and heat release, and then flows out through the right collecting pipe in N ways, and after being merged by the diverter 6, enters the throttling device 8 for throttling, and then enters the second heat exchanger 9 for evaporation and heat absorption, and then returns to the compressor 7 through the four-way valve 200 to complete the cycle.

[0057] When the microchannel heat exchanger is used as an evaporator, ac and bd of the four-way valve 200 are connected, and the refrigerant discharged from the compressor 7 passes through the four-way valve 200 into the second heat exchanger 9 for condensation and heat release, and then enters the throttling device 8 for throttling, and then is split into N paths through the splitter 6 to enter the microchannel heat exchanger 100 for evaporation and heat absorption, and then flows out from the left collector outlet, and finally returns to the compressor 7 through the four-way valve 200 to complete the cycle.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A microchannel heat exchanger, characterized in that: include: A manifold (1) and an inner insert tube (2), wherein the inner insert tube (2) is inserted into the inner cavity (10) of the manifold and is capable of introducing fluid into the inner cavity of the manifold (1) or of guiding fluid in the inner cavity of the manifold (1) out through the inner insert tube (2), and the portion of the inner insert tube (2) extending into the inner cavity is bent and extends upward along the length direction of the manifold, and a tube section at the free end or close to the free end of the inner insert tube (2) is formed into a tapered tube section (21), so that the tapered tube section (21) is formed into a tube section whose cross-sectional area gradually decreases from bottom to top, and a plurality of injection holes (22) are provided on the free end; The manifold (1) extends in a vertical direction and comprises a plurality of inner cavities (10), and the plurality of inner cavities (10) are arranged in sequence in an upper and lower manner; at least one partition (11) is provided inside the manifold (1), and adjacent inner cavities (10) are separated by the partition (11); and one inner insert tube (2) is provided in each of the inner cavities (10); The free end is a first straight pipe section (23), a plurality of the injection holes (22) are provided on the peripheral wall of the first straight pipe section (23) and are connected to the interior thereof, and at least one injection hole (22) is also provided on the top end of the first straight pipe section (23); the upper end of the tapered pipe section (21) is connected to the first straight pipe section (23), the two are connected to each other internally, and / or the tapered pipe section (21) is a nozzle with a smooth curved transition on the outer wall.

2. The microchannel heat exchanger according to claim 1, characterized in that: The inner insert pipe (2) further comprises a second straight pipe section (24), wherein the second straight pipe section (24) is arranged at the lower end of the tapered pipe section (21) and is in communication with the interior of the tapered pipe section (21).

3. The microchannel heat exchanger according to claim 2, characterized in that: The second straight pipe section (24) is longer than the first straight pipe section (23).

4. The microchannel heat exchanger according to claim 2, characterized in that: The inner insert pipe (2) further comprises an outer pipe section (25) located outside the collecting pipe (1), one end of the outer pipe section (25) being connected to the second straight pipe section (24) and the other end of the outer pipe section (25) being connected to the flow divider (6).

5. The microchannel heat exchanger according to any one of claims 1 to 4, characterized in that: It also comprises at least one flat tube (3), one end of the flat tube (3) being inserted into the inner cavity (10) of the collecting tube (1) and being in communication with the inner cavity (10), and at least two flat tubes (3) being arranged correspondingly to each inner cavity (10), with a preset spacing between adjacent flat tubes (3).

6. The microchannel heat exchanger according to claim 5, characterized in that: It also comprises a second header (4), the other end of the flat tube (3) being inserted into the second header (4), and the second header (4) is also connected to an air intake pipe (5).

7. A heat pump system, characterized in that: The microchannel heat exchanger (100) comprises the microchannel heat exchanger (100) according to any one of claims 1 to 6, and further comprises a compressor (7), a throttling device (8) and a second heat exchanger (9), wherein the compressor (7), the second heat exchanger (9), the throttling device (8) and the microchannel heat exchanger (100) are connected in sequence.

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