Microchannel heat exchanger, refrigerant circulation system, heat pump water heater, and air conditioner

Abstract

The present disclosure relates to a microchannel heat exchanger, a heat pump water heater, and an air conditioner. The microchannel heat exchanger comprises: a first manifold; a second manifold; and a plurality of flat tubes. One end of each flat tube is connected to the first manifold, the other end thereof is connected to the second manifold, and the flat tube is provided with a plurality of micropores in communication with the first manifold and the second manifold; the plurality of flat tubes comprise at least one superheated region flat tube used for circulating a gaseous working medium in a superheated state and at least one supercooled region flat tube used for circulating a liquid working medium in a supercooled state; and the total cross-sectional area of the micropores of the superheated region flat tube is greater than the total cross-sectional area of the micropores of the supercooled region flat tube; or the first manifold extends in a first direction; the second manifold and the first manifold are arranged side by side and spaced apart from each other; the plurality of flat tubes are arranged side by side in the first direction between the first manifold and the second manifold, the flat tubes extending in a second direction perpendicular to the first direction; one end of each flat tube in the second direction is in communication with the first manifold, and the other end thereof is in communication with the second manifold; and the ratio of the total volume of the plurality of flat tubes to the area of an outer heat exchange surface of the microchannel heat exchanger is 0.3 to 0.5.

Description

Microchannel heat exchanger, refrigerant circulation system, heat pump water heater and air conditioner

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 202311239441.2 and application date September 25, 2023 and the Chinese patent application with application number 202311314281.3 and application date October 11, 2023, and claims their priority. The disclosed contents of these two Chinese patent applications are hereby introduced into this application as a whole. Technical Field

[0003] The present disclosure relates to the field of heat exchange technology, and in particular to a microchannel heat exchanger, a refrigerant circulation system, a heat pump water heater, and an air conditioner. Background Art

[0004] A microchannel heat exchanger (MCHE) transfers heat through micron-sized channels. Its compact size and high surface-to-volume ratio make it suitable for applications requiring high heat flux and compact spaces. Due to its high heat transfer efficiency, compact size and weight, and strong reliability, MCHs are widely used in automotive air conditioning, electronic device cooling, aerospace, energy, and other fields.

[0005] For a general parallel flow microchannel heat exchanger, under given design conditions, the specifications, dimensions and internal structures of the flat tubes in different heat exchange areas of the microchannel heat exchanger unit are consistent.

[0006] Refrigerant (coolant) is the "blood" of the heat pump system. The heat pump system is a closed system. The system pipes and components need to be filled with liquid and gaseous refrigerant to maintain a normal circulation state. In other words, the heat pump system pipes and components will "store" refrigerant. When the refrigerant filling volume is constant, the more refrigerant stored in the pipeline, the less "effective" refrigerant participating in the heat pump cycle, the lower the refrigerant utilization rate, and the worse the system performance. Generally speaking, increasing the refrigerant filling volume of the heat pump system can improve the nominal operating conditions and high-temperature heating capacity, but it will also cause too much refrigerant at low temperatures, resulting in poor reliability. In addition, for heat pump systems with limited refrigerant filling volume (for example, for (vertical water tank) air-to-water heaters using R290 as the refrigerant, the refrigerant filling volume must be ≤152g), it is particularly important to reduce the refrigerant storage volume in the system pipes and improve the system refrigerant utilization rate.

[0007] Summary of the Invention

[0008] In one aspect of the present disclosure, a microchannel heat exchanger is provided, comprising: a first header, a second header, and a plurality of flat tubes; wherein: each flat tube has one end connected to the first header and the other end connected to the second header, and has a plurality of micropores connecting the first and second headers. The plurality of flat tubes include: at least one superheating zone flat tube for circulating a superheated gaseous working medium and at least one subcooling zone flat tube for circulating a subcooled liquid working medium, the total cross-sectional area of ​​the micropores of the superheating zone flat tube being greater than the total cross-sectional area of ​​the micropores of the subcooling zone flat tubes; or the second header is arranged side by side and spaced apart from the first header, the plurality of flat tubes are arranged side by side along a first direction between the first and second headers, the flat tubes extend along a second direction perpendicular to the first direction, one end of the flat tube along the second direction communicating with the first header and the other end communicating with the second header, and the ratio of the total volume of the plurality of flat tubes to the area of ​​the heat exchange outer surface of the microchannel heat exchanger is 0.3 to 0.5.

[0009] In some embodiments, the number of micropores in the superheating zone flat tube is greater than the number of micropores in the supercooling zone flat tube, and / or the cross-sectional area of ​​each micropore in the superheating zone flat tube is greater than the cross-sectional area of ​​each micropore in the supercooling zone flat tube.

[0010] In some embodiments, at least a portion of the micropores of the supercooling zone flat tube are provided with an internal tooth structure.

[0011] In some embodiments, the plurality of flat tubes are arranged at intervals along a first direction, and the inner tooth structure includes at least one protrusion extending along the length direction of the micropores of the micropore cold zone flat tube, and the protrusion protrudes on at least one of the two inner walls opposite to each other along the first direction of the micropores of the supercooling zone flat tube.

[0012] In some embodiments, the inner tooth structure includes two protrusions, which protrude respectively on two inner walls of the micropores of the supercooling zone flat tube that are opposite to each other along the first direction.

[0013] In some embodiments, the two protrusions are opposite to each other in the first direction.

[0014] In some embodiments, the number of micropores in the flat tubes in the superheating zone is 24-28, and the number of micropores in the flat tubes in the supercooling zone is 19-23.

[0015] In some embodiments, the cross-sectional area of ​​each micropore in the superheated zone flat tube is 0.403-0.542 mm 2 The cross-sectional area of ​​each micropore in the supercooling zone flat tube is 0.235-0.343 mm 2 .

[0016] In some embodiments, in the second direction perpendicular to the microporous cross section, the outer cross-sectional area of ​​the superheating zone flat tube and the outer cross-sectional area of ​​the supercooling zone flat tube are both 32.38-33.53 mm 2 .

[0017] In some embodiments, the ratio of the total cross-sectional area of ​​the micropores of the flat tubes in the superheating zone to the total cross-sectional area of ​​the micropores of the flat tubes in the supercooling zone is 1.3 to 3.4.

[0018] In some embodiments, the total cross-sectional area of ​​the micropores of the superheated zone flat tube is 10.32 to 15.176 mm 2 The total cross-sectional area of ​​the micropores of the supercooling zone flat tube is 4.465 to 7.889 mm 2 .

[0019] In some embodiments, the plurality of flat tubes further include at least one gas-liquid two-phase zone flat tube for circulating a gas-liquid two-phase working medium, and the total micropore cross-sectional area of ​​the gas-liquid two-phase zone flat tube is greater than the total micropore cross-sectional area of ​​the supercooling zone flat tube.

[0020] In some embodiments, the number of micropores in the flat tubes in the gas-liquid two-phase region is greater than the number of micropores in the flat tubes in the supercooling region, and / or the cross-sectional area of ​​each micropore in the gas-liquid two-phase region is greater than the cross-sectional area of ​​each micropore in the flat tubes in the supercooling region.

[0021] In some embodiments, the number of micropores in the flat tube in the gas-liquid two-phase region is 24-28.

[0022] In some embodiments, the cross-sectional area of ​​each micropore in the gas-liquid two-phase flat tube is 0.403-0.542 mm 2 .

[0023] In some embodiments, in the second direction perpendicular to the microporous cross section, the outer contour cross-sectional area of ​​the gas-liquid two-phase region flat tube is 32.38-33.53 mm 2 .

[0024] In some embodiments, the ratio of the total cross-sectional area of ​​the micropores of the flat tubes in the gas-liquid two-phase region to the total cross-sectional area of ​​the micropores of the flat tubes in the supercooling region is 1.3 to 3.4.

[0025] In some embodiments, the total cross-sectional area of ​​the micropores of the gas-liquid two-phase flat tube is 10.32 to 15.176 mm 2 .

[0026] In some embodiments, the multiple flat tubes are arranged at intervals along a first direction. In the first direction, the at least one gas-liquid two-phase zone flat tube is located between the at least one superheat zone flat tube and the at least one subcooling zone flat tube. The number of the subcooling zone flat tubes in the microchannel heat exchanger is greater than the number of the superheat zone flat tubes, and greater than the number of the gas-liquid two-phase zone flat tubes.

[0027] In some embodiments, the microchannel heat exchanger includes: a first heat exchange zone, including at least one of the flat tubes; and a second heat exchange zone, including at least one of the flat tubes, and the second heat exchange zone is located downstream of the first heat exchange zone along the flow direction of the refrigerant; the ratio of the total volume of the flat tubes in the first heat exchange zone to the area of ​​the heat exchange outer surface of the first heat exchange zone is greater than the ratio of the total volume of the flat tubes in the second heat exchange zone to the area of ​​the heat exchange outer surface of the second heat exchange zone.

[0028] In some embodiments, the ratio of the total volume of the flat tubes in the first heat exchange zone to the area of ​​the heat exchange outer surface of the first heat exchange zone is 0.4 to 0.5; and / or the ratio of the total volume of the flat tubes in the second heat exchange zone to the area of ​​the heat exchange outer surface of the second heat exchange zone is 0.28-0.37.

[0029] In some embodiments, the cross-section of the flat tube perpendicular to the second direction is strip-shaped, and the flat tube includes a plurality of channels for flowing refrigerant, which are arranged side by side along the length direction of the bar and extend along the second direction, wherein the number of channels of the flat tube in the first heat exchange zone is greater than the number of channels of the flat tube in the second heat exchange zone; and / or the cross-sectional area of ​​the channels of the flat tube in the first heat exchange zone is greater than the cross-sectional area of ​​at least part of the channels of the flat tube in the second heat exchange zone.

[0030] In some embodiments, the flat tubes in the first heat exchange zone are configured to circulate a superheated refrigerant having a temperature higher than a saturation temperature; and the flat tubes in the second heat exchange zone are configured to circulate a refrigerant in both gaseous and liquid states.

[0031] In some embodiments, a protrusion structure is provided on the inner wall of the channel in the flat tube of the second heat exchange zone.

[0032] In some embodiments, the protrusion structure extends along the second direction or extends spirally on the inner wall of the channel.

[0033] In some embodiments, the microchannel heat exchanger also includes a third heat exchange zone located downstream of the second heat exchange zone along the refrigerant flow direction, the third heat exchange zone includes at least one flat tube, and the ratio of the total volume of the flat tubes in the third heat exchange zone to the area of ​​the heat exchange outer surface of the third heat exchange zone is smaller than the ratio of the total volume of the flat tubes in the first heat exchange zone to the area of ​​the heat exchange outer surface of the first heat exchange zone.

[0034] In some embodiments, the ratio of the total volume of the flat tubes in the third heat exchange zone to the area of ​​the heat exchange outer surface of the third heat exchange zone is equal to or smaller than the ratio of the total volume of the flat tubes in the second heat exchange zone to the area of ​​the heat exchange outer surface of the second heat exchange zone.

[0035] In some embodiments, the ratio of the total volume of the flat tubes in the third heat exchange zone to the area of ​​the heat exchange outer surface of the third heat exchange zone is 0.28-0.37.

[0036] In some embodiments, the ratio of the total volume of the flat tubes in the third heat exchange zone to the area of ​​the heat exchange outer surface of the third heat exchange zone is 0.25-0.33.

[0037] In some embodiments, the flat tubes of the second heat exchange zone are configured to circulate a refrigerant having a temperature lower than a saturation temperature.

[0038] In some embodiments, the microchannel heat exchanger further includes: a first isolation component, arranged in the first manifold to block the inner cavity of the first manifold, wherein the microchannel heat exchanger includes a first group of flat tubes located on one side of the first isolation component and a second group of flat tubes located on the other side of the first isolation component, the first end of the first group of flat tubes along the second direction and the first end of the second group of flat tubes along the second direction are separated by the first isolation component, and the second end of the first group of flat tubes along the second direction and the second end of the second group of flat tubes are connected through the second manifold.

[0039] In one aspect of the present disclosure, a refrigerant circulation system is provided, comprising the aforementioned microchannel heat exchanger.

[0040] In one aspect of the present disclosure, a heat pump water heater is provided, comprising the aforementioned refrigerant circulation system or the aforementioned microchannel heat exchanger.

[0041] In one aspect of the present disclosure, an air conditioner is provided, comprising the aforementioned refrigerant circulation system or the aforementioned microchannel heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0043] The present disclosure can be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0044] FIG1 is a schematic structural diagram of a microchannel heat exchanger according to some embodiments of the present disclosure;

[0045] FIG2 is a schematic cross-sectional view of a flat tube in a superheated zone of a microchannel heat exchanger according to some embodiments of the present disclosure;

[0046] 3 is a cross-sectional schematic diagram of a flat tube in a supercooling zone of a microchannel heat exchanger according to some embodiments of the present disclosure;

[0047] 4 is a cross-sectional schematic diagram of a flat tube in a gas-liquid two-phase region in a microchannel heat exchanger according to some embodiments of the present disclosure;

[0048] FIG5 shows a schematic structural diagram of a heat pump water heater according to an embodiment of the present disclosure;

[0049] FIG6 shows a schematic structural diagram of a microchannel heat exchanger according to an embodiment of the present disclosure;

[0050] FIG7 shows a schematic structural diagram of heat exchange tubes in the first heat exchange zone of a microchannel heat exchanger according to an embodiment of the present disclosure; and

[0051] FIG8 is a schematic structural diagram of heat exchange tubes in the second heat exchange zone of a microchannel heat exchanger according to an embodiment of the present disclosure;

[0052] FIG9 shows a schematic structural diagram of heat exchange tubes in the third heat exchange zone of a microchannel heat exchanger according to an embodiment of the present disclosure;

[0053] FIG10 is a schematic structural diagram showing heat exchange tubes in the second heat exchange zone of a microchannel heat exchanger according to another optional embodiment of the present disclosure;

[0054] FIG11 shows a schematic structural diagram of heat exchange tubes in the second heat exchange zone of a microchannel heat exchanger according to another optional embodiment of the present disclosure; and

[0055] FIG12 shows a schematic structural diagram of heat exchange tubes in the second heat exchange zone of a microchannel heat exchanger according to another optional embodiment of the present disclosure.

[0056] It should be understood that the size of each part shown in the drawings is not drawn according to the actual proportional relationship.In addition, the same or similar reference numerals represent the same or similar components. DETAILED DESCRIPTION

[0057] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the present disclosure, its application, or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of parts and steps, the composition of materials, numerical expressions, and numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary and not as limiting.

[0058] The terms "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. The terms "include" or "comprises" and similar terms mean that the elements before the term include the elements listed after the term, and do not exclude the possibility of also including other elements. The terms "upper", "lower", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0059] In the present disclosure, when a specific device is described as being located between a first device and a second device, an intervening device may or may not be present between the specific device and the first device or the second device. When a specific device is described as being connected to another device, the specific device may be directly connected to the other device without an intervening device, or may be not directly connected to the other device but with an intervening device.

[0060] All terms (including technical or scientific terms) used in this disclosure have the same meaning as those understood by one of ordinary skill in the art to which this disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in, for example, general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or highly formal sense, unless explicitly defined herein.

[0061] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0062] In order to optimize the microchannel heat exchanger, the embodiment of the present disclosure provides a microchannel heat exchanger, comprising: a first header, a second header, and a plurality of flat tubes; wherein: one end of each flat tube is connected to the first header, and the other end is connected to the second header, and has a plurality of micropores connecting the first header and the second header, and the plurality of flat tubes include: at least one superheating zone flat tube for circulating a gas working medium in a superheated state and at least one subcooling zone flat tube for circulating a liquid working medium in a subcooled state, and the superheating zone flat tube The total cross-sectional area of ​​the micropores is greater than the total cross-sectional area of ​​the micropores of the flat tubes in the supercooling zone; or the second header is arranged side by side and at intervals with the first header, the multiple flat tubes are arranged side by side along a first direction between the first header and the second header, the flat tubes extend along a second direction perpendicular to the first direction, one end of the flat tube along the second direction is connected to the first header, and the other end is connected to the second header, and the ratio of the total volume of the multiple flat tubes to the area of ​​the heat exchange outer surface of the microchannel heat exchanger is 0.3 to 0.5.

[0063] The multiple flat tubes connecting the first collecting pipe and the second collecting pipe include superheating zone flat tubes for circulating gaseous working medium in a superheated state and subcooling zone flat tubes for circulating liquid working medium in a subcooled state according to the form of the working medium flowing therethrough, and the total cross-sectional area of ​​the micropores of the superheating zone flat tubes is made larger than the total cross-sectional area of ​​the micropores of the subcooling zone flat tubes. In this way, the working medium flow rate is reduced by setting a larger total cross-sectional area of ​​the micropores of the superheating zone flat tubes to reduce the pressure drop, and the working medium flow rate is increased by using a smaller total cross-sectional area of ​​the micropores of the subcooling zone flat tubes to enhance the heat exchange effect, thereby taking into account the heat exchange performance and pressure drop of the microchannel heat exchanger and improving the overall operating performance.

[0064] By optimizing the ratio of the total volume of the multiple flat tubes to the heat exchange surface area of ​​the microchannel heat exchanger, the refrigerant within the flat tubes can fully exchange heat with the heat exchange medium. This effectively reduces the refrigerant injection volume while maintaining the heat exchange performance of the refrigerant circulation system. Even when the first heat exchanger is at a low temperature, external heat can be fully utilized, thereby improving the system's low-temperature performance.

[0065] In some related technologies, the specifications, dimensions, and internal structures of the flat tubes in different heat exchange zones of a parallel flow microchannel heat exchanger are consistent. The inventors have discovered that these flat tubes with consistent specifications, dimensions, and internal structures in related technologies do not easily achieve a balanced balance between heat exchange performance and pressure drop in the microchannel heat exchanger, thereby hindering overall operational performance.

[0066] In view of this, the embodiments of the present disclosure provide a microchannel heat exchanger, a heat pump water heater, and an air conditioner, which can take into account the heat exchange performance and pressure drop of the microchannel heat exchanger and improve the overall operating performance.

[0067] Figure 1 is a schematic diagram of the structure of a microchannel heat exchanger according to some embodiments of the present disclosure. Figure 2 is a schematic cross-sectional view of a flat tube in the superheat zone of a microchannel heat exchanger according to some embodiments of the present disclosure. Figure 3 is a schematic cross-sectional view of a flat tube in the subcooling zone of a microchannel heat exchanger according to some embodiments of the present disclosure.

[0068] Referring to Figures 1-3, embodiments of the present disclosure provide a microchannel heat exchanger. The microchannel heat exchanger includes a first manifold A-10, a second manifold A-20, and a plurality of flat tubes. Each flat tube is connected to the first manifold A-10 at one end and to the second manifold A-20 at the other end. Each flat tube has a plurality of micropores connecting the first and second manifolds A-10 and A-20. The first manifold is also referred to as the first liquid header, and the second manifold is also referred to as the second liquid header.

[0069] The plurality of flat tubes include: at least one superheating zone flat tube A-31 for circulating a gaseous working medium in a superheated state and at least one subcooling zone flat tube A-33 for circulating a liquid working medium in a subcooled state. The total micropore cross-sectional area S1 of the superheating zone flat tube A-31 is greater than the total micropore cross-sectional area S3 of the subcooling zone flat tube A-33.

[0070] The superheat zone flat tubes are flat tubes in a microchannel heat exchanger used to handle superheated (above the saturated vapor temperature) gaseous working fluids. In this zone, the working fluid's temperature rises, exceeding the saturated vapor temperature and transitioning to a saturated vapor state. The subcooling zone flat tubes are flat tubes in a microchannel heat exchanger used to handle subcooled (above the liquid saturation temperature) liquid working fluids. In this zone, the working fluid's temperature decreases, approaching the liquid's saturation temperature.

[0071] In this embodiment, the total micropore cross-sectional area S1 of the superheating zone flat tube A-31 refers to the sum of the areas formed by all micropores A-311 within the superheating zone flat tube A-31, measured perpendicular to the direction of micropore extension. This refers to the sum of the cross-sectional areas of all micropores A-311. For superheating zone flat tubes A-31 employing micropores A-311 of the same cross-sectional area, the total micropore cross-sectional area S1 is the product of the number of micropores and the cross-sectional area of ​​each micropore. For superheating zone flat tubes A-31 employing micropores of different cross-sectional areas, the total micropore cross-sectional area S1 is the sum of the cross-sectional areas of each micropore.

[0072] Similarly, the total micropore cross-sectional area S3 of the supercooling zone flat tube A-33 refers to the sum of the areas formed by all micropores A-311 within the supercooling zone flat tube A-33, measured perpendicular to the direction of micropore extension. This refers to the sum of the cross-sectional areas of all micropores A-311. For supercooling zone flat tubes A-33 employing micropores A-311 of the same cross-sectional area, the total micropore cross-sectional area S3 is the product of the number of micropores and the cross-sectional area of ​​each micropore. For supercooling zone flat tubes A-33 employing micropores of different cross-sectional areas, the total micropore cross-sectional area S3 is the sum of the cross-sectional areas of each micropore.

[0073] Considering that the gaseous working fluid flowing through the superheated flat tubes has latent heat of phase change, creates a more ample heat exchange area with the microporous inner wall, and has a higher flow rate, the heat transfer coefficient is high, resulting in a correspondingly larger pressure drop, which increases energy consumption and reduces energy efficiency. Furthermore, the high pressure drop has an adverse effect on operational stability. By using a larger total microporous cross-sectional area in the superheated flat tubes A-31, the working fluid flow rate is reduced, thereby lowering the pressure drop. This helps reduce energy consumption, improve energy efficiency, and enhance the operational stability of the heat exchanger.

[0074] Considering that the heat transfer coefficient of the liquid working fluid flowing through the subcooling zone flat tubes is smaller than that of the gaseous working fluid, resulting in lower heat transfer efficiency, enhanced heat transfer is necessary. Therefore, by using a smaller total micropore cross-sectional area in the subcooling zone flat tubes A-33, the working fluid flow rate is increased, enhancing the heat transfer effect. This embodiment thus balances the heat transfer performance and pressure drop of the microchannel heat exchanger, improving overall operational performance.

[0075] In some embodiments, the ratio of the total cross-sectional area of ​​the micropores of the superheating zone flat tube A-31 to the total cross-sectional area of ​​the micropores of the supercooling zone flat tube A-33 is 1.3 to 3.4.

[0076] In this embodiment, if the total micropore cross-sectional area of ​​the superheating zone flat tubes A-31 is too large compared to the total micropore cross-sectional area of ​​the subcooling zone flat tubes A-33, the working fluid flow rate in the superheating zone will be significantly reduced, affecting the heat exchange efficiency, while the pressure drop in the subcooling zone will increase, affecting the stability of the heat exchanger. Conversely, if the total micropore cross-sectional area of ​​the superheating zone flat tubes A-31 is too small compared to the total micropore cross-sectional area of ​​the subcooling zone flat tubes A-33, the pressure drop in the superheating zone will be higher, affecting the operational stability of the heat exchanger, while the working fluid flow rate in the subcooling zone will be reduced, affecting the heat exchange efficiency in the subcooling zone. Therefore, by setting the ratio of the total micropore cross-sectional area of ​​the superheating zone flat tubes A-31 to the total micropore cross-sectional area of ​​the subcooling zone flat tubes A-33 to 1.3-3.4, a balance between the heat exchange efficiency and operational stability of the heat exchanger is achieved.

[0077] In some embodiments, the total cross-sectional area of ​​the micropores of the superheated zone flat tube A-31 is 10.32 to 15.176 mm 2The total cross-sectional area of ​​the micropores of the supercooling zone flat tube A-33 is 4.465 to 7.889 mm 2 .

[0078] For the superheating zone flat tube A-31, if the total cross-sectional area of ​​its micropores is too large, the working fluid flow rate in the superheating zone will be reduced too much, which will affect the heat exchange effect. If the total cross-sectional area of ​​its micropores is too small, the working fluid in the superheating zone will have a higher flow rate, resulting in a higher pressure drop, which will affect the operational stability of the heat exchanger. Therefore, the total cross-sectional area of ​​the micropores of the superheating zone flat tube A-31 is set to 10.32~15.176mm 2 , thus taking into account the heat exchange effect and operation stability of the heat exchanger.

[0079] For the supercooling zone flat tube A-33, if the total cross-sectional area of ​​its micropores is too large, the working fluid flow rate of the liquid working fluid with a low heat transfer coefficient in the supercooling zone will be low, which will greatly reduce the heat transfer effect. If the total cross-sectional area of ​​its micropores is too small, the working fluid flow rate in the supercooling zone will be too fast, which will lead to a high pressure drop in the supercooling zone and affect the operating stability of the heat exchanger. Therefore, the total cross-sectional area of ​​the micropores of the supercooling zone flat tube A-33 is 4.465~7.889mm 2 , thus taking into account the heat exchange effect and operation stability of the heat exchanger.

[0080] Referring to Figures 2 and 3, in some embodiments, the number N1 of micropores in the superheating zone flat tube A-31 is greater than the number N3 of micropores in the supercooling zone flat tube A-33. The superheating zone flat tube A-31 uses a larger number of micropores, which can increase the total cross-sectional area of ​​the micropores, reduce the flow rate of the working fluid, and thus reduce the pressure drop. Furthermore, by increasing the contact area between the gaseous working fluid and the micropores, the heat transfer surface area is increased. Furthermore, more micropores can make the heat distribution more uniform, which is conducive to balanced heat exchange and reduces the risk of local overheating. The supercooling zone flat tube A-33 uses a smaller number of micropores, which can reduce the total cross-sectional area of ​​the micropores, increase the flow rate of the working fluid, improve the heat transfer efficiency, and help reduce the complexity and cost of manufacturing and processing. It is also conducive to obtaining a larger spacing between the micropores, thereby reducing the interference between adjacent micropores.

[0081] In some embodiments, the number N1 of micropores in the superheating zone flat tube A-31 is 24 to 28, for example, 24, 25, 26, 27, or 28, and the number N3 of micropores in the supercooling zone flat tube A-33 is 19 to 23, for example, 19, 20, 21, 22, or 23. By making the number N1 of micropores in the superheating zone flat tube A-31 24 to 28 and the number N3 of micropores in the supercooling zone flat tube A-33 19 to 23, the total cross-sectional area of ​​the micropores in the superheating zone flat tube A-31 can be increased, the flow rate of the gaseous working medium in the superheating zone flat tube A-31 can be reduced, the pressure drop in the superheating zone flat tube A-31 can be reduced, the heat transfer surface area of ​​the superheating zone flat tube A-31 can be increased, the risk of local overheating can be reduced, and the complexity and cost of manufacturing and processing of the supercooling zone flat tube A-33 can be reduced, and the micropores of the supercooling zone flat tube A-33 can be made to have a larger spacing, thereby reducing the interference between adjacent micropores in the supercooling zone flat tube A-33.

[0082] In some embodiments, the cross-sectional area of ​​each micropore A-311 in the superheating zone flat tube A-31 is larger than the cross-sectional area of ​​each micropore A-3A-31 in the subcooling zone flat tube A-33. Using larger micropore cross-sectional areas in the superheating zone flat tube A-31 can increase the total micropore cross-sectional area, reduce the flow rate of the working fluid, and thus reduce pressure drop. The larger micropore cross-sectional area also reduces the flow resistance of the working fluid through the micropores, which also helps reduce pressure drop. Using smaller micropore cross-sectional areas in the subcooling zone flat tube A-33 can increase the flow rate of the working fluid and improve heat transfer efficiency.

[0083] In some embodiments, the cross-sectional area of ​​each micropore A-311 in the superheated zone flat tube A-31 is 0.403-0.542 mm 2 , for example 0.403mm 2 , 0.45mm 2 , 0.5mm 2 , 0.542mm 2 The cross-sectional area of ​​each micropore A-331 in the supercooling zone flat tube A-33 is 0.235 to 0.343 mm 2 , for example 0.235mm 2 , 0.27mm 2 , 0.3mm 2 , 0.34mm 2 By making the cross-sectional area of ​​each micropore in the superheated zone flat tube A-31 0.403~0.542mm 2 , and make the cross-sectional area of ​​each micropore in the supercooling zone flat tube A-33 be 0.235~0.343mm 2, which can increase the total cross-sectional area of ​​the micropores of the superheated zone flat tube A-31, reduce the flow resistance of the working medium when passing through the micropores, reduce the flow rate of the gaseous working medium in the superheated zone flat tube A-31, reduce the pressure drop of the superheated zone flat tube A-31, and is conducive to increasing the flow rate of the working medium in the supercooled zone flat tube A-33, thereby improving the heat transfer efficiency.

[0084] In the above embodiment, in the second direction x perpendicular to the micropore cross section (which may also be the length direction or extension direction of the micropore), the outer cross-sectional area of ​​the superheating zone flat tube A-31 and the outer cross-sectional area of ​​the supercooling zone flat tube A-33 may be the same or substantially the same, for example, both are 32.38 to 33.53 mm. 2 , which is conducive to making the overall structural dimensions of the microchannel heat exchanger more consistent.

[0085] In some embodiments, the number N1 of micropores in the superheating zone flat tubes A-31 is greater than the number N3 of micropores in the subcooling zone flat tubes A-33, and the cross-sectional area S of each micropore A-311 in the superheating zone flat tubes A-31 is greater than the cross-sectional area S of each micropore A-331 in the subcooling zone flat tubes A-33. Using a larger number of micropores and a larger cross-sectional area in the superheating zone flat tubes A-31 can increase the total cross-sectional area of ​​the micropores, reduce the flow rate of the working fluid, and thus reduce pressure drop. Furthermore, a larger number of micropores and a larger cross-sectional area increase the contact area between the gaseous working fluid and the micropores, increasing the heat transfer surface area. More micropores can achieve more uniform heat distribution, facilitating balanced heat exchange and reducing the risk of localized overheating. A larger cross-sectional area of ​​the micropores reduces the flow resistance of the working fluid through the micropores, also helping to reduce pressure drop.

[0086] Referring to Figure 3, in some embodiments, at least some of the micropores A-331 of the subcooling zone flat tubes A-33 are provided with internal tooth structures A-332. The internal tooth structures A-332 of the subcooling zone flat tubes A-33 increase the surface area for heat transfer between the micropores and the liquid working medium, and can also increase the flow disturbance of the liquid working medium, promoting turbulence and increasing the flow rate of the liquid working medium.

[0087] In Figures 1 and 3 , the multiple flat tubes may be spaced apart along a first direction z. The first direction z may be perpendicular to a second direction x, and the micropores in each flat tube may be spaced apart along a third direction y perpendicular to both the first and second directions z. The internal tooth structure A-332 includes at least one protrusion extending along the length of the micropores of the micropore cold zone flat tubes (i.e., the second direction x). The protrusion protrudes from at least one of the two inner walls of the micropores A-331 of the supercooling zone flat tubes A-33 that oppose each other in the first direction z.

[0088] A protrusion is a structure that protrudes inward from the inner wall of a micropore. This protrusion extends along the length of the micropore of the micropore cold-zone flat tube and is located on one or both of the inner walls of the micropore A-331 that oppose each other in the first direction z. As shown in Figure 3, because the protrusion is located on the inner wall of the micropore corresponding to the flat outer surface (i.e., the wide side surface) of the supercooling-zone flat tube A-33, the heat exchange efficiency of the wide side surface of the flat tube is enhanced.

[0089] In Figure 3 , the internal tooth structure A-332 may include two protrusions, one disposed on two opposing inner walls of the micropores A-331 of the subcooling zone flat tubes A-33 along the first direction z. Providing protrusions on both opposing inner walls of the micropores A-331 along the first direction z facilitates increased heat exchange efficiency on the opposing wide side surfaces of the subcooling zone flat tubes A-33.

[0090] Referring to Figure 3 , in some embodiments, the two protrusions are positioned opposite each other in the first direction z. By providing two opposing protrusions on two opposing inner walls of micropore A-331 in the first direction z, the flow of the liquid working medium across the cross-section can be made more uniform, reducing energy consumption. Furthermore, the protrusions can be positioned centrally within micropore A-331 in the third direction y.

[0091] Figure 4 is a schematic cross-sectional view of a gas-liquid two-phase zone flat tube in a microchannel heat exchanger according to some embodiments of the present disclosure. Referring to Figures 1 and 4, in some embodiments, the plurality of flat tubes further includes at least one gas-liquid two-phase zone flat tube A-32 for circulating a gas-liquid two-phase working medium. The total micropore cross-sectional area S2 of gas-liquid two-phase zone flat tube A-32 is greater than the total micropore cross-sectional area S3 of the supercooling zone flat tube A-33.

[0092] Gas-liquid two-phase flat tubes are flat tubes used in microchannel heat exchangers to process mixed gas-liquid working fluids. In this region, the working fluid contains both gas and liquid phases and is typically used for gas-liquid phase change heat transfer, such as vaporization or condensation.

[0093] Taking into account the presence of liquid accumulation on the inner wall of the micropores in the gas-liquid two-phase zone, which makes the actual flow size of the micropores smaller, and the gas-liquid two-phases disturb each other during flow, resulting in energy loss, and the undulating movement of the liquid part in the micropores will also cause energy loss, thereby making the flat tube pressure drop in this area larger. By making the total micropore cross-sectional area S2 of the flat tube A-32 in the gas-liquid two-phase zone larger than the total micropore cross-sectional area S3 of the flat tube A-33 in the supercooling zone, the working fluid flow rate is reduced by the larger total micropore cross-sectional area S2 of the flat tube A-32 in the gas-liquid two-phase zone to reduce the pressure drop, thereby reducing energy consumption, improving energy utilization efficiency, and improving the operating stability of the heat exchanger.

[0094] In this embodiment, the total micropore cross-sectional area S2 of the gas-liquid two-phase flat tube A-32 refers to the sum of the areas formed by all micropores A-321 within the gas-liquid two-phase flat tube A-32, measured perpendicular to the direction of micropore extension. This refers to the sum of the cross-sectional areas of all micropores A-321. For gas-liquid two-phase flat tubes A-32 employing micropores A-321 of the same cross-sectional area, the total micropore cross-sectional area S2 is the product of the number of micropores and the cross-sectional area of ​​each micropore. For gas-liquid two-phase flat tubes A-32 employing micropores of different cross-sectional areas, the total micropore cross-sectional area S2 is the sum of the cross-sectional areas of each micropore.

[0095] In some embodiments, the ratio of the total cross-sectional area of ​​the micropores of the gas-liquid two-phase region flat tube A-32 to the total cross-sectional area of ​​the micropores of the supercooling region flat tube A-33 is 1.3 to 3.4.

[0096] In this embodiment, if the total micropore cross-sectional area of ​​the flat tubes A-32 in the gas-liquid two-phase region is too large compared to the total micropore cross-sectional area of ​​the flat tubes A-33 in the subcooling region, the working medium flow rate in the gas-liquid two-phase region will be significantly reduced, affecting the heat exchange efficiency, while the pressure drop in the subcooling region will increase, affecting the stability of the heat exchanger. Conversely, if the total micropore cross-sectional area of ​​the flat tubes A-32 in the gas-liquid two-phase region is too small compared to the total micropore cross-sectional area of ​​the flat tubes A-33 in the subcooling region, the working medium flow rate in the gas-liquid two-phase region will be too high, exacerbating the mutual disturbance between the gas and liquid phases during flow, resulting in a high pressure drop in the gas-liquid two-phase region, affecting the operational stability of the heat exchanger, and reducing the working medium flow rate in the subcooling region, affecting the heat exchange efficiency in the subcooling region. Therefore, by setting the ratio of the total micropore cross-sectional area of ​​the flat tubes A-32 in the gas-liquid two-phase region to the total micropore cross-sectional area of ​​the flat tubes A-33 in the subcooling region to 1.3-3.4, a balance between the heat exchange efficiency and operational stability of the heat exchanger is achieved.

[0097] In some embodiments, the total cross-sectional area of ​​the micropores of the gas-liquid two-phase flat tube A-32 is 10.32 to 15.176 mm 2 .

[0098] For the flat tube A-32 in the gas-liquid two-phase zone, if the total cross-sectional area of ​​its micropores is too large, the working fluid flow rate of the liquid working fluid with a low heat transfer coefficient in the gas-liquid two-phase zone will be low, which will greatly reduce the heat transfer effect. If the total cross-sectional area of ​​its micropores is too small, the working fluid flow rate in the gas-liquid two-phase zone will be too fast, which will aggravate the mutual disturbance between the gas and liquid phases during flow, resulting in a high pressure drop in the gas-liquid two-phase zone and affecting the operational stability of the heat exchanger. Therefore, the total cross-sectional area of ​​the micropores of the flat tube A-32 in the gas-liquid two-phase zone is 10.32~15.176mm 2 , thus taking into account the heat exchange effect and operation stability of the heat exchanger.

[0099] Referring to Figure 1, in some embodiments, the plurality of flat tubes are arranged at intervals along a first direction z. In the first direction z, the at least one gas-liquid two-phase flat tube A-32 is located between the at least one superheating flat tube A-31 and the at least one subcooling flat tube A-33. The number of subcooling flat tubes A-33 in the microchannel heat exchanger is greater than the number of superheating flat tubes A-31 and greater than the number of gas-liquid two-phase flat tubes A-32. The heat exchange capacity of the subcooling flat tubes A-33 is lower than that of the superheating flat tubes A-31 and the gas-liquid two-phase heat pipes A-32. Therefore, providing more subcooling flat tubes A-33 improves the heat exchange capacity of the microchannel heat exchanger.

[0100] For example, the microchannel heat exchanger can be divided into three processes, wherein the first process corresponds to the superheating zone and the gas-liquid two-phase zone of the microchannel heat exchanger, and therefore includes two superheating zone flat tubes A-31 and three gas-liquid two-phase zone heat pipes A-32; the second process and the third process both correspond to the subcooling zone of the microchannel heat exchanger, wherein the second process includes three subcooling zone flat tubes A-33, and the third process includes two subcooling zone flat tubes A-33, so the microchannel heat exchanger includes five subcooling zone flat tubes A-33.

[0101] With reference to Figures 3 and 4, in some embodiments, the number N2 of micropores in the gas-liquid two-phase region flat tubes A-32 is greater than the number N3 of micropores in the subcooling region flat tubes A-33. The use of a larger number of micropores in the gas-liquid two-phase region flat tubes A-32 increases the total cross-sectional area of ​​the micropores, reduces the flow rate of the working fluid, and thus reduces pressure drop. Furthermore, by increasing the contact area between the gas-liquid two-phase working fluid and the micropores, the heat transfer surface area is increased. Furthermore, a larger number of micropores ensures more uniform heat distribution, facilitating balanced heat exchange and reducing the risk of localized overheating.

[0102] In some embodiments, the number N2 of micropores in the gas-liquid two-phase region flat tubes A-32 is 24 to 28, for example, 24, 25, 26, 27, or 28, while the number N3 of micropores in the supercooling region flat tubes A-33 is less than N2 and can be 19 to 23, for example, 19, 20, 21, 22, or 23. By setting the number N2 of micropores in the gas-liquid two-phase region flat tubes A-32 to 24 to 28, the total cross-sectional area S2 of the micropores in the gas-liquid two-phase region flat tubes A-32 can be increased, the flow rate of the gas-liquid two-phase working medium in the gas-liquid two-phase region flat tubes A-32 can be reduced, the pressure drop in the gas-liquid two-phase region flat tubes A-32 can be reduced, the heat transfer surface area of ​​the gas-liquid two-phase region flat tubes A-32 can be increased, and the risk of local overheating can be reduced.

[0103] In some embodiments, the cross-sectional area of ​​each micropore A-321 in the gas-liquid two-phase region flat tube A-32 is larger than the cross-sectional area of ​​each micropore A-331 in the supercooling region flat tube A-33. Using larger micropore cross-sectional areas in the gas-liquid two-phase region flat tube A-32 can increase the total micropore cross-sectional area, reduce the working fluid flow rate, and thus reduce pressure drop. This can also offset, to a certain extent, the reduction in micropore flow size caused by liquid accumulation on the micropore inner wall, thereby reducing flow resistance of the working fluid through the micropores and minimizing mutual disturbance between the gas and liquid phases.

[0104] In some embodiments, the cross-sectional area of ​​each micropore in the gas-liquid two-phase region flat tube A-32 is 0.403-0.542 mm 2 , for example 0.403mm 2 , 0.45mm 2 , 0.5mm 2 , 0.542mm 2 The cross-sectional area of ​​each micropore A-331 in the supercooling zone flat tube A-33 is smaller than the micropore cross-sectional area of ​​the gas-liquid two-phase zone flat tube A-32, for example, 0.235 to 0.343 mm 2 , for example 0.235mm 2 , 0.27mm 2 , 0.3mm 2 , 0.34mm 2 By making the cross-sectional area of ​​each micropore in the gas-liquid two-phase flat tube A-32 0.403~0.542mm 2 , which can increase the total cross-sectional area of ​​the micropores of the flat tube A-32 in the gas-liquid two-phase area, reduce the flow resistance of the working fluid when passing through the micropores, reduce the flow velocity of the gas-liquid two-phase working fluid in the flat tube A-32 in the gas-liquid two-phase area, and reduce the pressure drop of the flat tube A-32 in the gas-liquid two-phase area.

[0105] In the above embodiment, in the second direction x perpendicular to the micropore cross section (which may also be the length direction or extension direction of the micropore), the outer cross-sectional area of ​​the gas-liquid two-phase zone flat tube A-32 may be the same or substantially the same as the outer cross-sectional area of ​​the superheat zone flat tube A-31 and the supercool zone flat tube A-33, for example, both are 32.38 to 33.53 mm. 2 , which is conducive to making the overall structural dimensions of the microchannel heat exchanger more consistent.

[0106] In some embodiments, the number N2 of micropores in the flat tube A-32 in the gas-liquid two-phase zone is greater than the number N3 of micropores in the flat tube A-33 in the supercooling zone, and the cross-sectional area of ​​each micropore A-321 in the flat tube A-32 in the gas-liquid two-phase zone is greater than the cross-sectional area of ​​each micropore A-3A-31 in the flat tube A-33 in the supercooling zone.

[0107] The flat tube A-32 in the gas-liquid two-phase area adopts a larger number of micropores and a larger micropore cross-sectional area, which can increase the total micropore cross-sectional area, reduce the working fluid flow rate, thereby reducing the pressure drop, and increase the heat transfer surface area by increasing the contact area between the gas-liquid two-phase working fluid and the micropores. Moreover, more micropores can make the heat distribution more uniform, which is conducive to balanced heat exchange and reduces the risk of local overheating. The larger micropore cross-sectional area can offset to a certain extent the reduction of the micropore flow size caused by liquid accumulation on the inner wall of the micropore, reduce the flow resistance when the working fluid passes through the micropore, and reduce the mutual disturbance of the gas-liquid two-phase working fluid.

[0108] Referring to the previous examples, we selected various flat tubes with varying total micropore cross-sectional areas for cross-combination of superheat zone flat tubes, gas-liquid two-phase zone flat tubes, and subcooling zone flat tubes, and conducted full-machine testing. The table below shows the test results for these 19 cross-combination schemes.

[0109] The table above shows the heat transfer, system power consumption, and system coefficient of performance (COP) achieved under different values ​​of the total micropore cross-sectional area of ​​the superheated zone flat tubes, gas-liquid two-phase zone flat tubes, and superheated zone flat tubes. Ignoring the test errors caused by test accuracy, it can be seen from the table above that in the 1st, 2nd, 8th, 9th, 12th, 13th, 15th, 16th, and 17th cross-matching schemes, the system COP can achieve a relatively good result of more than 3.1. According to the values ​​of the total micropore cross-sectional area of ​​the superheated zone flat tubes, gas-liquid two-phase zone flat tubes, and superheated zone flat tubes corresponding to these schemes, it can be seen that the total micropore cross-sectional area of ​​the superheated zone flat tubes and gas-liquid two-phase zone flat tubes ranges from 10.32 to 15.176 mm. 2 , and the total cross-sectional area of ​​the micropores of the flat tube in the superheated zone is 4.465~7.889mm 2 When the system COP is optimized, a better system COP can be achieved, thereby improving the overall operating performance.

[0110] In related technologies, when the refrigerant filling volume is constant, the more refrigerant is stored in the pipeline, the less "effective" refrigerant is involved in the heat pump cycle, the lower the refrigerant utilization rate, and the worse the system performance. Generally speaking, increasing the refrigerant filling volume of the heat pump system can improve the nominal operating conditions and high-temperature heating capacity, but it will also cause too much refrigerant at low temperatures, resulting in poor reliability. In addition, for heat pump systems with limited refrigerant filling volume (such as (vertical water tank) air-to-water heaters using R290 as refrigerant, the refrigerant filling volume must be ≤152g), it is particularly important to reduce the refrigerant storage volume in the system pipeline and improve the refrigerant utilization rate of the system.

[0111] In view of this, an embodiment of the present disclosure provides a microchannel heat exchanger that is beneficial for improving the utilization rate of refrigerant.

[0112] As shown in FIG5 , the heat pump water heater of this embodiment includes a refrigerant circulation system, which includes a compressor 10, a first heat exchanger 40, and a second heat exchanger 60. One of the first heat exchanger 40 and the second heat exchanger 60 functions as a condenser, and the other functions as an evaporator. The condenser is connected to the exhaust port of the compressor 10 to condense the compressed refrigerant discharged by the compressor 10. The evaporator is connected to the intake port of the compressor 10 to transport the evaporated refrigerant to the compressor 10 for recompression. The heat pump water heater also includes a heat exchange medium housing 70 for exchanging heat with the second heat exchanger 60. The side of the second heat exchanger 60 is attached to the heat exchange medium housing 70. The side of the second heat exchanger 60 attached to the heat exchange medium housing 70 exchanges heat with the heat exchange medium within the heat exchange medium housing 70.

[0113] In some embodiments, the heat exchange medium includes water. The heat exchange medium housing 70 includes a water tank.

[0114] In some embodiments, the refrigerant circulation system further includes a four-way valve 30, which includes an inlet D connected to the exhaust port of the compressor 10, an outlet S connected to the intake port of the compressor 10, a first working port E connected to the first heat exchanger 40, and a second working port C connected to the second heat exchanger 60. The four-way valve 30 has a first operating state and a second operating state. When the four-way valve 30 is in the first operating state, the inlet D is connected to the first working port E, the outlet S is connected to the second working port C, the first heat exchanger 40 functions as a condenser, and the second heat exchanger 60 functions as an evaporator. When the four-way valve 30 is in the second operating state, the inlet D is connected to the second working port C, the outlet S is connected to the first working port E, the first heat exchanger 40 functions as an evaporator, and the second heat exchanger 60 functions as a condenser.

[0115] In some embodiments, a gas-liquid separator 20 is further included that is connected to the air intake of the compressor 10 , the inlet of the gas-liquid separator 20 is connected to the outlet S of the four-way valve 30 , and the outlet of the gas-liquid separator 20 is connected to the air intake of the compressor 10 .

[0116] In some embodiments, the refrigerant circulation system further includes a fan 50 for driving air to exchange heat with the first heat exchanger 40. The refrigerant circulation system further includes a throttling component 80 located between the first heat exchanger 40 and the second heat exchanger 60 along the refrigerant flow direction.

[0117] In this embodiment, the second heat exchanger 60 is a microchannel heat exchanger, also known as a microchannel heat exchanger.

[0118] As shown in Figure 6, the microchannel heat exchanger includes a refrigerant inlet 4, a refrigerant outlet 5, and a plurality of flat tubes 3. The refrigerant inlet 4 is used to introduce refrigerant for heat exchange with an external medium; the refrigerant outlet 5 is used to output the refrigerant after heat exchange with the external medium. The plurality of flat tubes 3 are arranged side by side along a first direction and extend in a second direction perpendicular to the first direction. One end of the flat tube 3 along the second direction is connected to the refrigerant inlet 4, and the other end is connected to the refrigerant outlet 5. The ratio of the total volume of the plurality of flat tubes 3 to the area of ​​the heat exchange outer surface of the microchannel heat exchanger is 0.3 to 0.5.

[0119] In this embodiment, the ratio of the total volume of the multiple flat tubes 3 to the area of ​​the microchannel heat exchanger's outer heat exchange surface is optimized to ensure sufficient heat exchange between the refrigerant within the flat tubes 3 and the heat exchange medium. This effectively reduces the refrigerant injection volume while maintaining the heat exchange performance of the refrigerant circulation system. Even when the first heat exchanger is at a low temperature, external heat can be fully utilized, thereby improving the system's low-temperature performance.

[0120] The following table shows the performance parameter comparison of microchannel condensers with different flat tube specifications:

[0121] For pipes or components with the same volume, the density of liquid refrigerant is much greater than that of gaseous or gas-liquid mixed refrigerant at the same refrigerant temperature and pressure, so the amount of liquid refrigerant stored therein is greater than that of gaseous or gaseous mixed refrigerant. For example, when using R290 refrigerant, at a temperature of 60°C and a pressure of 2.1168MPa, the densities of saturated liquid and saturated gas are 427.97kg / m 3 and 49.49kg / m 3 , 1m 3 Liquid R290 refrigerant weighs 8.6 times the mass of the same volume of gaseous refrigerant. The refrigerant in the condenser condenses from gas to liquid, which contains more liquid and accounts for a larger proportion of the refrigerant mass. Therefore, the key to improving refrigerant utilization in a refrigerant system lies in reducing the refrigerant storage capacity in the water tank heat exchanger, while ensuring the heat exchange surface area of ​​the microchannel heat exchanger. This means reducing the internal volume of the second heat exchanger 60.

[0122] The microchannel heat exchanger includes a first heat exchange zone 3a and a second heat exchange zone 3b. The first heat exchange zone 3a includes at least one flat tube 3; the second heat exchange zone 3b also includes at least one flat tube 3. The second heat exchange zone 3b is located downstream of the first heat exchange zone 3a along the flow direction of the refrigerant.

[0123] The ratio of the total volume of the flat tubes 3 in the first heat exchange zone 3a to the area of ​​the heat exchange outer surface of the first heat exchange zone 3a is greater than the ratio of the total volume of the flat tubes 3 in the second heat exchange zone 3b to the area of ​​the heat exchange outer surface of the second heat exchange zone 3b.

[0124] As the refrigerant flows in the heat exchanger, it continuously exchanges heat with the external medium. The high-temperature refrigerant gradually condenses into liquid refrigerant, reducing the volume of the flat tubes in the second heat exchange area 3b located downstream, which is beneficial to reducing the refrigerant injection volume and also beneficial to increasing the refrigerant flow rate, strengthening the turbulent heat exchange in the tube and thus improving the heat transfer performance of the microchannel heat exchanger.

[0125] In this embodiment, the flat tubes 3 of the first heat exchange zone 3a are directly connected to the refrigerant inlet 4. When the second heat exchanger 60 is used as a condenser, the first heat exchange zone 3a is used to condense the high-temperature, high-pressure refrigerant compressed by the compressor. The first heat exchange zone 3a is a refrigerant superheat zone, where the refrigerant exists in a gaseous state. At the same condensing pressure, the volume occupied by gaseous refrigerant is larger than that of liquid refrigerant. If the internal volume of the microchannel flat tube heat exchanger is too small, the heat exchanger's resistance loss will increase, and excessive pressure drop will reduce heat exchange performance. The second heat exchange zone 3b contains the refrigerant condensed in the first heat exchange zone 3a. The refrigerant in the second heat exchange zone 3b is in a gas-liquid two-phase mixture. At the same condensing pressure, the volume occupied by liquid refrigerant is smaller than that of gaseous refrigerant. Appropriately reducing the internal volume of the microchannel heat exchanger's flat tubes helps increase the gas-liquid two-phase refrigerant flow rate, enhance turbulent heat exchange within the tubes, and thus improve the heat transfer performance of the microchannel heat exchanger.

[0126] In some embodiments, the ratio of the total volume of the flat tubes 3 of the first heat exchange region 3 a to the area of ​​the heat exchange outer surface of the first heat exchange region 3 a is 0.4 to 0.5.

[0127] In some embodiments, the ratio of the total volume of the flat tubes 3 in the second heat exchange region 3 b to the area of ​​the heat exchange outer surface of the second heat exchange region 3 b is 0.28-0.37.

[0128] The flat tube 3 has a strip-shaped cross section perpendicular to the second direction. The flat tube 3 includes channels 31 arranged side by side along the length of the strip and extending along the second direction for the flow of refrigerant. In some embodiments, the cross section of the flat tube 3 is a strip extending along the first direction.

[0129] The number of channels 31 of the flat tubes 3 in the first heat exchange zone 3a is greater than the number of channels 31 of the flat tubes 3 in the second heat exchange zone 3b. FIG7 shows a schematic structural diagram of a cross section of the flat tubes 3 in the first heat exchange zone 3a, and FIG8 shows a schematic structural diagram of a cross section of the flat tubes 3 in the second heat exchange zone 3b. The number of channels of the flat tubes 3 in the first heat exchange zone 3a is greater than the number of channels 31 of the flat tubes 3 in the second heat exchange zone 3b, so that the volume of the flat tubes 3 in the first heat exchange zone 3a is greater than the volume of the flat tubes 3 in the second heat exchange zone 3b.

[0130] The cross-sectional area of ​​the pores 31 of the flat tubes 3 in the first heat exchange zone 3a is larger than the cross-sectional area of ​​at least part of the pores 31 of the flat tubes 3 in the second heat exchange zone 3b. FIG7 shows a schematic structural diagram of the cross-sectional view of the flat tubes 3 in the first heat exchange zone 3a, and FIG8 shows a schematic structural diagram of the cross-sectional view of the flat tubes 3 in the second heat exchange zone 3b. The cross-sectional area of ​​the pores 31 of the flat tubes 3 in the first heat exchange zone 3a is larger than the cross-sectional area of ​​the pores 31 of the flat tubes 3 in the second heat exchange zone 3b, so that the volume of the flat tubes 3 in the first heat exchange zone 3a is larger than the volume of the flat tubes 3 in the second heat exchange zone 3b.

[0131] In some embodiments, raised structures 32 are provided on the inner walls of the pores 31 of the second heat exchange section 3b, thereby increasing the volume of the flat tubes 3 in the first heat exchange section 3a relative to the volume of the flat tubes 3 in the second heat exchange section 3b. Furthermore, providing raised structures on the inner walls 3 of the pores 31 facilitates enhancing turbulent heat transfer within the tubes, thereby improving the heat transfer performance of the microchannel heat exchanger. It also helps increase the internal surface area of ​​the pores 31, thereby improving heat exchange performance.

[0132] In some embodiments, the raised structure 32 extends along the second direction, aligning with the length of the flat tube 3, thereby simplifying the manufacturing process and reducing production costs. In other embodiments, the raised structure 32 extends spirally along the inner wall of the channel 31, thereby enhancing the turbulent flow of the refrigerant within the channel 31 and improving heat exchange performance.

[0133] The microchannel heat exchanger also includes a third heat exchange zone 3c located downstream of the second heat exchange zone 3b along the refrigerant flow direction. The third heat exchange zone 3c includes at least one flat tube 3. The ratio of the total volume of the flat tubes 3 in the third heat exchange zone 3c to the area of ​​the heat exchange outer surface of the third heat exchange zone 3c is smaller than the ratio of the total volume of the flat tubes 3 in the first heat exchange zone 3a to the area of ​​the heat exchange outer surface of the first heat exchange zone 3a.

[0134] The third heat exchange zone 3c is used to condense the refrigerant after heat exchange in the second heat exchange zone 3b. The refrigerant in the third heat exchange zone 3c is in a supercooled state. In the supercooled zone, appropriately reducing the internal volume of the microchannel heat exchanger flat tube 3 helps to increase the flow rate of the liquid refrigerant, thereby improving the heat transfer performance of the microchannel heat exchanger.

[0135] In some embodiments, the ratio of the total volume of the flat tubes 3 of the third heat exchange region 3c to the area of ​​the heat exchange outer surface of the third heat exchange region 3c is 0.28-0.37.

[0136] In some embodiments, the ratio of the total volume of the flat tubes 3 of the third heat exchange zone 3c to the area of ​​the heat exchange outer surface of the third heat exchange zone 3c is equal to or less than the ratio of the total volume of the flat tubes 3 of the second heat exchange zone 3b to the area of ​​the heat exchange outer surface of the second heat exchange zone 3b.

[0137] The refrigerant within the flat tubes 3 of the third heat exchanger section 3c is a subcooled, liquid refrigerant with a temperature below the saturation temperature. At the same condensing pressure, liquid refrigerant occupies a smaller volume than gaseous or dual-phase refrigerant. Appropriately reducing the internal volume of the flat tubes 3 in the third heat exchanger section 3c helps increase refrigerant flow rate, enhance turbulent heat transfer within the tubes, and ultimately improve the heat transfer performance of the microchannel heat exchanger.

[0138] In some embodiments, the ratio of the total volume of the flat tubes 3 of the third heat exchange region 3c to the area of ​​the heat exchange outer surface of the third heat exchange region 3c is 0.25-0.33.

[0139] In some embodiments, the cross section of the flat tube 3 perpendicular to the second direction is strip-shaped, and the flat tube 3 includes channels 31 for flowing refrigerant, which are arranged side by side along the first direction and extend along the second direction.

[0140] The number of channels 31 of the flat tubes 3 in the first heat exchange zone 3a is greater than the number of channels 31 of the flat tubes 3 in the third heat exchange zone 3c. FIG7 shows a schematic structural diagram of a cross section of the flat tubes 3 in the first heat exchange zone 3a, and FIG9 shows a schematic structural diagram of a cross section of the flat tubes 3 in the third heat exchange zone 3c. The number of channels of the flat tubes 3 in the first heat exchange zone 3a is greater than the number of channels 31 of the flat tubes 3 in the third heat exchange zone 3c, so that the volume of the flat tubes 3 in the first heat exchange zone 3a is greater than the volume of the flat tubes 3 in the third heat exchange zone 3c.

[0141] The cross-sectional area of ​​the channels 31 of the flat tubes 3 in the first heat exchange zone 3a is greater than the cross-sectional area of ​​at least a portion of the channels 31 of the flat tubes 3 in the third heat exchange zone 3c. Figure 7 shows a schematic cross-sectional structural diagram of the flat tubes 3 in the first heat exchange zone 3a, and Figure 9 shows a schematic cross-sectional structural diagram of the flat tubes 3 in the third heat exchange zone 3c. The cross-sectional area of ​​the channels 31 of the flat tubes 3 in the first heat exchange zone 3a is greater than the cross-sectional area of ​​the channels 31 of the flat tubes 3 in the third heat exchange zone 3c, so that the volume of the flat tubes 3 in the first heat exchange zone 3a is greater than the volume of the flat tubes 3 in the third heat exchange zone 3c.

[0142] As shown in FIG. 10 and FIG. 12 , in some embodiments, the flat tubes 3 of the second heat exchange zone 3 b or the third heat exchange zone 3 c have fewer channels 31 than the flat tubes 3 of the first heat exchange zone 3 a .

[0143] As shown in FIG11 , in some embodiments, the flat tube 3 of the second heat exchange zone 3b or the third heat exchange zone 3c includes a first channel 311 and a second channel 312 , and the cross-sectional area of ​​the second channel 312 is smaller than the cross-sectional area of ​​the first channel 311 .

[0144] The microchannel heat exchanger further includes a first manifold 1, a second manifold 2, and a first isolation member 6. The first manifold 1 is disposed at the first end of the flat tubes 3 along the second direction and is in communication with the first ends of the plurality of flat tubes 3 along the second direction. The second manifold 2 is disposed at the second end of the flat tubes 3 along the second direction and is connected to the second ends of the plurality of flat tubes 3 along the second direction. The first isolation member 6 is disposed within the first manifold 1 to block the inner cavity of the first manifold 1.

[0145] The microchannel heat exchanger includes a first group of flat tubes 3 located on one side of a first isolation member 6 and a second group of flat tubes 3 located on the other side of the first isolation member 6. The first end of the first group of flat tubes 3 along the second direction is separated from the first end of the second group of flat tubes 3 along the second direction by the first isolation member 6. The second end of the first group of flat tubes 3 along the second direction is connected to the second end of the second group of flat tubes 3 via a second manifold 2. This helps extend the refrigerant flow path within the heat exchanger, ensuring sufficient contact and heat exchange between the refrigerant and the external heat exchange medium.

[0146] Furthermore, a second isolation component 7 is provided in the second manifold 2. The working principle of the second isolation component 7 is similar to that of the first isolation component 6, and the second isolation component 7 cooperates with the first isolation component 6 to form a return channel for the multiple flat tubes 3 in the microchannel heat exchanger. For example, the refrigerant in the flat tubes 3 of the first heat exchange zone 3a flows from the first manifold 1 to the second manifold 2, the refrigerant in the flat tubes 3 of the second heat exchange zone 3b flows from the second manifold 2 to the first manifold 1, and the refrigerant in the flat tubes 3 of the third heat exchange zone 3c flows from the first manifold 1 to the second manifold 2.

[0147] Specifically, the optimal ratio of the inner volume to the outer surface area of ​​the flat tubes 3 in the first heat exchange zone 3a is 0.46. For a flat tube with a size of 25.4 mm (width) x 1.3 mm (height) (with a square inner hole) as an example, the optimal number of holes is 26, as shown in Figure 3.

[0148] The optimal ratio of the flat tube's internal volume to external surface area in the second heat exchange zone 3b or the third heat exchange zone 3c is 0.33. Taking a flat tube with dimensions of 25.4 mm (width) x 1.3 mm (height) as an example, a preferred solution is to design the inner holes in an internal tooth shape with 21 holes, as shown in Figures 9 and 10.

[0149] According to another aspect of the present disclosure, a refrigerant circulation system is further provided, and the refrigerant circulation system includes the above-mentioned microchannel heat exchanger.

[0150] According to another aspect of the present disclosure, a heat pump water heater is provided. The heat pump water heater includes the above-mentioned refrigerant circulation system.

[0151] The microchannel heat exchangers of the above-mentioned embodiments are applicable to various equipment or business scenarios requiring heat exchange, such as heat pump water heaters or air conditioners.

[0152] Therefore, in one aspect of the present disclosure, a heat pump water heater is provided, comprising the microchannel heat exchanger of any of the aforementioned embodiments or the refrigerant circulation system of any of the aforementioned embodiments.

[0153] In another aspect of the present disclosure, an air conditioner is provided, comprising the microchannel heat exchanger of any of the aforementioned embodiments or the refrigerant circulation system of any of the aforementioned embodiments.

[0154] Thus far, various embodiments of the present disclosure have been described in detail. To avoid obscuring the concept of the present disclosure, some details known in the art have not been described. Based on the above description, those skilled in the art can fully understand how to implement the technical solutions disclosed herein.

[0155] Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art will understand that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. Those skilled in the art will understand that the above embodiments may be modified or some technical features may be replaced with equivalents without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A microchannel heat exchanger, comprising: A first header, a second header and a plurality of flat tubes; wherein: One end of each flat tube is connected to the first header, and the other end is connected to the second header, and each flat tube has a plurality of micropores communicating with the first header and the second header, wherein the plurality of flat tubes include: at least one superheating zone flat tube for circulating a gaseous working medium in a superheated state and at least one subcooling zone flat tube for circulating a liquid working medium in a subcooled state, and the total cross-sectional area of ​​the micropores of the superheating zone flat tube is greater than the total cross-sectional area of ​​the micropores of the subcooling zone flat tube; or The first collecting pipe extends along a first direction, the second collecting pipe is arranged side by side and at intervals with the first collecting pipe, the multiple flat tubes are arranged side by side between the first collecting pipe and the second collecting pipe along the first direction, the flat tubes extend along a second direction perpendicular to the first direction, one end of the flat tube along the second direction is connected to the first collecting pipe, and the other end is connected to the second collecting pipe, and the ratio of the total volume of the multiple flat tubes to the area of ​​the heat exchange outer surface of the microchannel heat exchanger is 0.3 to 0.

5.

2. The microchannel heat exchanger according to claim 1, wherein: The number of micropores in the superheating zone flat tube is greater than the number of micropores in the supercooling zone flat tube, and / or the cross-sectional area of ​​each micropore in the superheating zone flat tube is greater than the cross-sectional area of ​​each micropore in the supercooling zone flat tube.

3. The microchannel heat exchanger according to claim 2, wherein: At least part of the micropores of the supercooling zone flat tube are provided with an internal tooth structure.

4. The microchannel heat exchanger according to claim 3, wherein: The plurality of flat tubes are arranged at intervals along a first direction, and the inner tooth structure includes at least one protrusion extending along the length direction of the micropores of the micropore cold zone flat tube, and the protrusion protrudes from at least one of the two inner walls of the micropores of the supercooling zone flat tube that are opposite to each other along the first direction.

5. The microchannel heat exchanger according to claim 4, wherein: The inner tooth structure includes two protrusions, which are respectively protruded on two inner walls opposite to each other along the first direction of the micropores of the flat tube in the supercooling zone.

6. The microchannel heat exchanger according to claim 5, wherein: The two protrusions are opposite to each other in the first direction.

7. The microchannel heat exchanger according to any one of claims 2 to 6, wherein: The number of micropores in the flat tube in the superheating zone is 24 to 28, and the number of micropores in the flat tube in the supercooling zone is 19 to 23.

8. The microchannel heat exchanger according to any one of claims 2 to 6, wherein: The cross-sectional area of ​​each micropore in the flat tube in the overheating zone is 0.403-0.542 mm 2 The cross-sectional area of ​​each micropore in the supercooling zone flat tube is 0.235-0.343 mm 2 .

9. The microchannel heat exchanger according to any one of claims 2 to 6, wherein: In the second direction perpendicular to the microporous cross section, the outer contour cross-sectional area of ​​the superheated zone flat tube and the outer contour cross-sectional area of ​​the supercooled zone flat tube are both 32.38-33.53 mm 2 .

10. The microchannel heat exchanger according to any one of claims 1 to 9, wherein: The ratio of the total cross-sectional area of ​​the micropores of the flat tubes in the superheating zone to the total cross-sectional area of ​​the micropores of the flat tubes in the supercooling zone is 1.3 to 3.

4.

11. The microchannel heat exchanger according to any one of claims 1 to 10, wherein: The total cross-sectional area of ​​the micropores of the flat tube in the overheating zone is 10.32-15.176 mm 2 The total cross-sectional area of ​​the micropores of the supercooling zone flat tube is 4.465 to 7.889 mm 2 .

12. The microchannel heat exchanger according to any one of claims 1 to 11, wherein: The plurality of flat tubes further include at least one gas-liquid two-phase zone flat tube for circulating a gas-liquid two-phase working medium, and the total micropore cross-sectional area of ​​the gas-liquid two-phase zone flat tube is greater than the total micropore cross-sectional area of ​​the supercooling zone flat tube.

13. The microchannel heat exchanger according to claim 12, wherein: The number of micropores in the flat tube in the gas-liquid two-phase region is greater than the number of micropores in the flat tube in the supercooling region, and / or the cross-sectional area of ​​each micropore in the gas-liquid two-phase region is greater than the cross-sectional area of ​​each micropore in the flat tube in the supercooling region.

14. The microchannel heat exchanger according to claim 13, wherein: The number of micropores in the flat tube in the gas-liquid two-phase region is 24 to 28.

15. The microchannel heat exchanger according to claim 13 or 14, wherein: The cross-sectional area of ​​each micropore in the flat tube of the gas-liquid two-phase region is 0.403-0.542 mm 2 .

16. The microchannel heat exchanger according to any one of claims 13 to 15, wherein: In the second direction perpendicular to the microporous cross section, the outer contour cross-sectional area of ​​the gas-liquid two-phase region flat tube is 32.38-33.53 mm 2 .

17. The microchannel heat exchanger according to any one of claims 12 to 16, wherein: The ratio of the total cross-sectional area of ​​micropores of the flat tubes in the gas-liquid two-phase zone to the total cross-sectional area of ​​micropores of the flat tubes in the supercooling zone is 1.3 to 3.

4.

18. The microchannel heat exchanger according to claim 17, wherein: The total cross-sectional area of ​​the micropores of the flat tube in the gas-liquid two-phase region is 10.32-15.176 mm 2 .

19. The microchannel heat exchanger according to any one of claims 12 to 18, wherein: The multiple flat tubes are arranged at intervals along a first direction. In the first direction, the at least one flat tube in the gas-liquid two-phase zone is located between the at least one flat tube in the superheating zone and the at least one flat tube in the subcooling zone. The number of the flat tubes in the subcooling zone in the microchannel heat exchanger is greater than the number of the flat tubes in the superheating zone, and greater than the number of the flat tubes in the gas-liquid two-phase zone.

20. The microchannel heat exchanger according to claim 1, comprising: A first heat exchange zone, comprising at least one of the flat tubes; and A second heat exchange zone, comprising at least one of the flat tubes, wherein the second heat exchange zone is located downstream of the first heat exchange zone along the flow direction of the refrigerant; The ratio of the total volume of the flat tubes in the first heat exchange zone to the area of ​​the heat exchange outer surface of the first heat exchange zone is greater than the ratio of the total volume of the flat tubes in the second heat exchange zone to the area of ​​the heat exchange outer surface of the second heat exchange zone.

21. The microchannel heat exchanger according to claim 20, wherein: The ratio of the total volume of the flat tubes in the first heat exchange zone to the area of ​​the heat exchange outer surface of the first heat exchange zone is 0.4 to 0.5; and / or The total volume of the flat tubes in the second heat exchange zone is equal to the area of ​​the heat exchange outer surface of the second heat exchange zone. The ratio is 0.28-0.

37.

22. The microchannel heat exchanger according to claim 20 or 21, wherein: The flat tube has a cross section perpendicular to the second direction in a strip shape, and the flat tube includes a plurality of channels for flowing refrigerant, which are arranged side by side along the length direction of the strip and extend along the second direction. Wherein, the number of holes of the flat tubes in the first heat exchange zone is greater than the number of holes of the flat tubes in the second heat exchange zone; and / or The cross-sectional area of ​​the pores of the flat tubes in the first heat exchange zone is greater than the cross-sectional area of ​​at least part of the pores of the flat tubes in the second heat exchange zone.

23. The microchannel heat exchanger according to any one of claims 20 to 22, wherein: The flat tubes in the first heat exchange zone are configured to flow a superheated refrigerant having a temperature higher than a saturation temperature; The flat tubes in the second heat exchange zone are configured to flow refrigerant in gaseous and liquid states.

24. The microchannel heat exchanger according to any one of claims 20 to 23, wherein: A protrusion structure is arranged on the inner wall of the hole in the flat tube of the second heat exchange zone.

25. The microchannel heat exchanger according to claim 24, wherein: The protrusion structure extends along the second direction or spirally extends on the inner wall of the channel.

26. The microchannel heat exchanger according to any one of claims 20 to 25, further comprising a third heat exchange zone located downstream of the second heat exchange zone along the refrigerant flow direction, the third heat exchange zone comprising at least one of the flat tubes, the ratio of the total volume of the flat tubes in the third heat exchange zone to the area of ​​the heat exchange outer surface of the third heat exchange zone being smaller than the ratio of the total volume of the flat tubes in the first heat exchange zone to the area of ​​the heat exchange outer surface of the first heat exchange zone.

27. The microchannel heat exchanger according to claim 26, wherein: The ratio of the total volume of the flat tubes in the third heat exchange zone to the area of ​​the heat exchange outer surface of the third heat exchange zone is equal to or smaller than the ratio of the total volume of the flat tubes in the second heat exchange zone to the area of ​​the heat exchange outer surface of the second heat exchange zone.

28. The microchannel heat exchanger according to claim 27, wherein: The ratio of the total volume of the flat tubes in the third heat exchange zone to the area of ​​the heat exchange outer surface of the third heat exchange zone is 0.28-0.

37.

29. The microchannel heat exchanger according to claim 27 or 28, wherein: The ratio of the total volume of the flat tubes in the third heat exchange zone to the area of ​​the heat exchange outer surface of the third heat exchange zone is 0.25-0.

33.

30. The microchannel heat exchanger according to any one of claims 26 to 29, wherein: The flat tubes in the second heat exchange zone are configured to flow a refrigerant having a temperature lower than a saturation temperature.

31. The microchannel heat exchanger according to any one of claims 1 and 20 to 30, further comprising: a first isolation component, disposed in the first header to block the inner cavity of the first header, Wherein, the microchannel heat exchanger includes a first group of flat tubes located on one side of the first isolation component and a second group of flat tubes located on the other side of the first isolation component, the first end of the first group of flat tubes along the second direction and the first end of the second group of flat tubes along the second direction are separated by the first isolation component, and the second end of the first group of flat tubes along the second direction and the second end of the second group of flat tubes are connected through the second collecting pipe.

32. A refrigerant circulation system, comprising the microchannel heat exchanger according to any one of claims 1 to 31.

33. A heat pump water heater, comprising: The refrigerant circulation system according to claim 32 or the microchannel heat exchanger according to any one of claims 1 to 31.

34. An air conditioner comprising: The refrigerant circulation system according to claim 32 or the microchannel heat exchanger according to any one of claims 1 to 31.

Images