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

Abstract

The present invention relates to a microchannel heat exchanger, a refrigerant circulation system and a heat pump water heater. The microchannel heat exchanger comprises: a refrigerant inlet (4) for introducing a refrigerant for heat exchange with an external medium; a refrigerant outlet (5) for outputting the refrigerant after heat exchange with the external medium; a plurality of flat tubes (3) arranged side by side along a first direction, the flat tubes (3) extending along a second direction perpendicular to the first direction, one end of the flat tube (3) along the second direction being connected to the refrigerant inlet (4), and the other end being connected to the refrigerant outlet (5); a 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.

Description

Technical Field

[0001] The present invention relates to, in particular to, a microchannel heat exchanger, a refrigerant circulation system and a heat pump water heater. Background Art

[0002] 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. Summary of the Invention

[0003] The present invention aims to provide a microchannel heat exchanger, a refrigerant circulation system and a heat pump water heater which are conducive to improving the utilization rate of the refrigerant.

[0004] According to one aspect of an embodiment of the present invention, the present invention provides a microchannel heat exchanger, the microchannel heat exchanger comprising:

[0005] a first header extending along a first direction;

[0006] a second header, arranged side by side with and spaced apart from the first header;

[0007] A plurality of flat tubes are arranged side by side along a first direction between a first header and a second header, the flat tubes extending along a second direction perpendicular to the first direction, one end of the flat tube along the second direction being connected to the first header, and the other end being connected to the second header;

[0008] 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 microchannel heat exchanger comprises:

[0010] A first heat exchange zone includes at least one flat tube;

[0011] A second heat exchange zone includes at least one flat tube, and the second heat exchange zone is located downstream of the first heat exchange zone along the flow direction of the refrigerant;

[0012] 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.

[0013] In some embodiments,

[0014] 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

[0015] 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.

[0016] 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, arranged side by side along the length direction of the strip and extending along the second direction.

[0017] The number of channels in the flat tubes of the first heat exchange zone is greater than the number of channels in the flat tubes of the second heat exchange zone; and / or

[0018] The cross-sectional area of ​​the channels of the flat tubes in the first heat exchange zone is larger than the cross-sectional area of ​​at least part of the channels of the flat tubes in the second heat exchange zone.

[0019] In some embodiments,

[0020] The flat tubes in the first heat exchange zone are configured to circulate a superheated refrigerant having a temperature higher than the saturation temperature;

[0021] The flat tubes in the second heat exchange zone are configured to circulate refrigerants in both gaseous and liquid states.

[0022] In some embodiments, a protrusion structure is provided on the inner wall of the hole in the flat tube of the second heat exchange zone.

[0023] In some embodiments, the protrusion structure extends along the second direction or extends spirally on the inner wall of the hole.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] In some embodiments, the flat tubes in the second heat exchange zone are configured to flow a refrigerant having a temperature lower than a saturation temperature.

[0029] In some embodiments, it further includes:

[0030] a first isolation component, provided in the first manifold to block the inner cavity of the first manifold;

[0031] The microchannel heat exchanger includes a first group of flat tubes located on one side of a 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 a second collecting pipe.

[0032] According to another aspect of the present invention, a refrigerant circulation system is provided, including the above-mentioned microchannel heat exchanger.

[0033] According to another aspect of the present invention, a heat pump water heater is provided. The heat pump water heater includes the above-mentioned refrigerant circulation system.

[0034] By applying the technical solution of this application, the ratio of the total volume of the multiple flat tubes to the heat exchange surface area of ​​the microchannel heat exchanger is optimized, allowing the refrigerant in the flat tubes to 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 low-temperature performance of the system.

[0035] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1A schematic structural diagram of a heat pump water heater according to an embodiment of the present invention is shown;

[0038] Figure 2 A schematic structural diagram of a microchannel heat exchanger according to an embodiment of the present invention is shown;

[0039] Figure 3 A schematic diagram showing the structure of heat exchange tubes in a first heat exchange zone of a microchannel heat exchanger according to an embodiment of the present invention; and

[0040] Figure 4 A schematic structural diagram showing the heat exchange tubes in the second heat exchange zone of the microchannel heat exchanger according to an embodiment of the present invention is shown;

[0041] Figure 5 A schematic structural diagram showing the heat exchange tubes in the third heat exchange zone of the microchannel heat exchanger according to an embodiment of the present invention is shown;

[0042] Figure 6 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 invention is shown;

[0043] Figure 7 A schematic diagram showing the structure of heat exchange tubes in the second heat exchange zone of a microchannel heat exchanger according to another optional embodiment of the present invention; and

[0044] Figure 8 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 invention is shown. DETAILED DESCRIPTION

[0045] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0046] like Figure 1As shown, 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 serves as a condenser, and the other serves 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.

[0047] In some embodiments, the heat exchange medium includes water. The heat exchange medium housing 70 includes a water tank.

[0048] 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.

[0049] 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 .

[0050] 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.

[0051] In this embodiment, the second heat exchanger 60 is a microchannel heat exchanger, also known as a microchannel heat exchanger.

[0052] like Figure 2As shown, 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.

[0053] 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.

[0054] The following table shows the performance parameter comparison of microchannel condensers with different flat tube specifications:

[0055]

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] The number of holes 31 of the flat tubes 3 in the first heat exchange zone 3 a is greater than the number of holes 31 of the flat tubes 3 in the second heat exchange zone 3 b ; Figure 3 A schematic structural diagram showing a cross section of the flat tube 3 in the first heat exchange zone 3a is shown. Figure 4 A schematic structural diagram of a cross section of the flat tubes 3 of the second heat exchange zone 3b is shown. The number of channels in the flat tubes 3 of the first heat exchange zone 3a is greater than the number of channels 31 in the flat tubes 3 of 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.

[0065] 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. Figure 3 A schematic structural diagram showing a cross section of the flat tube 3 in the first heat exchange zone 3a is shown. Figure 4 A schematic structural diagram of a cross section of the flat tubes 3 of the second heat exchange zone 3b is shown. The cross-sectional area of ​​the pores of the flat tubes 3 of the first heat exchange zone 3a is larger than the cross-sectional area of ​​the pores 31 of the flat tubes 3 of the second heat exchange zone 3b, so that the volume of the flat tubes 3 of the first heat exchange zone 3a is larger than the volume of the flat tubes 3 of the second heat exchange zone 3b.

[0066] In some embodiments, raised structures 32 are provided on the inner walls of the channels 31 in the second heat exchange region 3b to increase the volume of the flat tubes 3 in the first heat exchange region 3a relative to the volume of the flat tubes 3 in the second heat exchange region 3b. Furthermore, providing raised structures on the inner walls of the channels 31 facilitates enhanced 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 channels 31, thereby enhancing heat exchange performance.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] The refrigerant within the flat tubes 3 of the third heat exchange zone 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 exchange zone 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.

[0073] 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.

[0074] 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.

[0075] The number of holes 31 of the flat tubes 3 in the first heat exchange zone 3 a is greater than the number of holes 31 of the flat tubes 3 in the third heat exchange zone 3 c ; Figure 3 A schematic structural diagram showing a cross section of the flat tube 3 in the first heat exchange zone 3a is shown. Figure 5 A schematic structural diagram of a cross section of the flat tubes 3 of the third heat exchange zone 3c is shown. The number of channels in the flat tubes 3 of the first heat exchange zone 3a is greater than the number of channels 31 in the flat tubes 3 of the third heat exchange zone 3c, so that the volume of the flat tubes 3 of the first heat exchange zone 3a is greater than the volume of the flat tubes 3 of the third heat exchange zone 3c.

[0076] The cross-sectional area of ​​the channels 31 of the flat tubes 3 in the first heat exchange zone 3 a is larger than the cross-sectional area of ​​at least part of the channels 31 of the flat tubes 3 in the third heat exchange zone 3 c . Figure 3 A schematic structural diagram showing a cross section of the flat tube 3 in the first heat exchange zone 3a is shown. Figure 5 A schematic structural diagram of a cross section of the flat tubes 3 of the third heat exchange zone 3c is shown. The cross-sectional area of ​​the channels of the flat tubes 3 of the first heat exchange zone 3a is larger than the cross-sectional area of ​​the channels 31 of the flat tubes 3 of the third heat exchange zone 3c, so that the volume of the flat tubes 3 of the first heat exchange zone 3a is larger than the volume of the flat tubes 3 of the third heat exchange zone 3c.

[0077] like Figure 6 and 8 As shown, 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 holes 31 than the flat tubes 3 of the first heat exchange zone 3 a .

[0078] like Figure 7 As shown, 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 .

[0079] 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.

[0080] 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.

[0081] 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.

[0082] Specifically, the optimal ratio of the inner volume to the outer surface area of ​​the flat tube 3 in the first heat exchange zone 3a is 0.46. Taking the flat tube specification of 25.4mm (width) × 1.3mm (height) (with a square inner hole) as an example, the optimal number of holes is 26, see Figure 3 .

[0083] The optimal ratio of the inner volume to the outer surface area of ​​the flat tube 3 in the second heat exchange zone 3b or the third heat exchange zone 3c is 0.33. Taking the flat tube with a size of 25.4mm (width) × 1.3mm (height) as an example, the optimal solution is to design the inner hole into an inner tooth shape with 21 holes, see Figure 4 and Figure 5 .

[0084] According to another aspect of the present invention, a refrigerant circulation system is provided. The refrigerant circulation system includes the above-mentioned microchannel heat exchanger.

[0085] According to another aspect of the present invention, a heat pump water heater is provided. The heat pump water heater includes the above-mentioned refrigerant circulation system.

[0086] The above are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A microchannel heat exchanger, characterized in that: include: A first collecting pipe (1) extending in a first direction; A second header (2) is arranged side by side with and spaced apart from the first header (1); A plurality of flat tubes (3) are arranged side by side along a first direction between the first header (1) and the second header (2); the flat tubes (3) extend along a second direction perpendicular to the first direction; one end of the flat tubes (3) along the second direction is connected to the first header (1), and the other end is connected to the second header (2); 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.

2. The microchannel heat exchanger according to claim 1, characterized in that: include: A first heat exchange zone (3a) comprising at least one of the flat tubes (3); A second heat exchange zone (3b) comprising at least one of the flat tubes (3), wherein the second heat exchange zone (3b) is located downstream of the first heat exchange zone (3a) along the flow direction of the refrigerant; 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).

3. The microchannel heat exchanger according to claim 2, characterized in that: The ratio of the total volume of the flat tubes (3) of the first heat exchange zone (3a) to the area of ​​the heat exchange outer surface of the first heat exchange zone (3a) is 0.4 to 0.5; and / or 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) is 0.28-0.

37.

4. The microchannel heat exchanger according to claim 2, characterized in that: The flat tube (3) has a strip-shaped cross section perpendicular to the second direction. The flat tube (3) includes a plurality of channels (31) for flowing refrigerant, which are arranged side by side along the length direction of the strip and extend along the second direction. The number of holes (31) of the flat tube (3) in the first heat exchange zone (3a) is greater than the number of holes (31) of the flat tube (3) in the second heat exchange zone (3b); and / or The cross-sectional area of ​​the pores (31) of the flat tubes (3) in the first heat exchange zone (3a) is greater 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).

5. The microchannel heat exchanger according to claim 2, characterized in that: The flat tubes (3) of the first heat exchange zone (3a) are configured to circulate a superheated refrigerant having a temperature higher than a saturation temperature; The flat tubes (3) of the second heat exchange zone (3b) are configured to circulate refrigerants in both gaseous and liquid states.

6. The microchannel heat exchanger according to any one of claims 2 to 4, characterized in that: A protruding structure (32) is provided on the inner wall of the hole (31) in the flat tube (3) of the second heat exchange zone (3b).

7. The microchannel heat exchanger according to any one of claim 6, characterized in that: The protruding structure (32) extends along the second direction or spirally extends on the inner wall of the hole (31).

8. The microchannel heat exchanger according to claim 2, characterized in that: It also includes a third heat exchange zone (3c) located downstream of the second heat exchange zone (3b) along the flow direction of the refrigerant, the third heat exchange zone (3c) including at least one of the flat tubes (3), and 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).

9. The microchannel heat exchanger according to claim 8, characterized in that: 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 smaller 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).

10. The microchannel heat exchanger according to claim 9, characterized in that: 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 0.28-0.

37.

11. The microchannel heat exchanger according to claim 9 or 10, characterized in that: 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 0.25-0.

33.

12. The microchannel heat exchanger according to claim 8, characterized in that: The flat tubes (3) of the second heat exchange zone (3b) are configured to circulate a refrigerant having a temperature lower than the saturation temperature.

13. The microchannel heat exchanger according to claim 1, characterized in that: Also includes: a first isolation component (6) provided in the first header (1) to block the inner cavity of the first header (1); The microchannel heat exchanger comprises a first group of flat tubes (3) located on one side of the first isolation component (6) and a second group of flat tubes (3) located on the other side of the first isolation component (6); a first end of the first group of flat tubes (3) along the second direction and a first end of the second group of flat tubes (3) along the second direction are separated by the first isolation component (6); and a second end of the first group of flat tubes (3) along the second direction and a second end of the second group of flat tubes (3) are connected via the second collecting pipe (2).

14. A refrigerant circulation system, characterized in that: The microchannel heat exchanger comprises the microchannel heat exchanger according to any one of claims 1 to 13.

15. A heat pump water heater, characterized in that: Includes the refrigerant circulation system according to claim 14.

Images