Finned heat exchanger and heat pump unit

Abstract

The application discloses a finned heat exchanger and a heat pump unit, which comprises a body part, a gas collecting pipe assembly, a distributor assembly and a plurality of flow paths, the plurality of flow paths are respectively arranged in the body part, one end of each flow path is communicated with the distributor assembly, and the other end is communicated with the gas collecting pipe assembly; each flow path comprises a first U-shaped pipe, a connecting pipe, a second U-shaped pipe, a tee joint, a third U-shaped pipe and a fourth U-shaped pipe, one end of the first U-shaped pipe is connected with the distributor assembly, the other end is connected with one end of the second U-shaped pipe through the connecting pipe, the other end of the second U-shaped pipe is connected with one port of the tee joint, the other two ports of the tee joint are respectively connected with the third U-shaped pipe and the fourth U-shaped pipe, and the third U-shaped pipe and the fourth U-shaped pipe are further connected with the gas collecting pipe assembly. The application considers the cost and does not increase the number of rows, reasonably sets the total length of each branch, makes the refrigerant fully exchange heat, and makes the refrigerant distribution more uniform due to the reduction of the number of distribution holes at the front end, reduces the pressure drop by being divided into two paths at the rear end, and makes the whole fin play a better energy efficiency.

Description

Technical Field

[0001] This application relates to the technical field of heat exchangers, and more particularly to a finned heat exchanger and a heat pump unit. Background Technology

[0002] As the heat pump industry continues to upgrade towards higher energy efficiency and lower energy consumption, optimizing the heat exchange performance of air source heat pump systems has become one of the core research and development directions. In air source heat pump systems, the finned heat exchanger, as the core heat exchange component on the air side, primarily functions to efficiently absorb low-grade heat energy from the air through heat exchange. Therefore, improving the heat exchange capacity on the finned side directly determines the overall energy efficiency level of the unit.

[0003] To enhance heat exchange, existing technologies commonly employ a design that reduces the diameter of the copper tubes. This increases the refrigerant's mass flow rate within the tubes, thereby improving the heat transfer coefficient and enhancing the overall heat exchange effect. However, this approach has inherent drawbacks: the increased refrigerant mass flow rate inevitably leads to a significant increase in system pressure drop. Especially for small-capacity units, balancing pressure drop control with heat exchange performance becomes a critical technical challenge. To address this issue, existing solutions propose a multi-row finned structure with a single-inlet, single-outlet flow path. While this can ensure a certain degree of uniformity in refrigerant distribution across the flow paths and control the pressure drop within a reasonable range, it requires additional complexity in the flow path layout and increases the cost of related components, leading to a rise in the overall unit design cost and hindering product market promotion and design optimization. Utility Model Content

[0004] The purpose of this application is to provide a finned heat exchanger and a heat pump unit to solve the technical problems existing in the prior art.

[0005] To achieve the above objectives, this application adopts the following technical solution: On the one hand, a finned heat exchanger and a heat pump unit are provided, including: a body, a gas collecting pipe assembly, a distributor assembly and multiple flow paths, wherein the multiple flow paths are respectively disposed in the body, and one end of each flow path is connected to the distributor assembly and the other end is connected to the gas collecting pipe assembly; The flow path includes a first U-tube, a connecting tube, a second U-tube, a tee, a third U-tube, and a fourth U-tube. One end of the first U-tube is connected to the distributor assembly, and the other end is connected to one end of the second U-tube through the connecting tube. The other end of the second U-tube is connected to one port of the tee. The other two ports of the tee are respectively connected to the third U-tube and the fourth U-tube. The third U-tube and the fourth U-tube are also respectively connected to the gas collecting pipe assembly.

[0006] Furthermore, the dispenser assembly includes one of a conical dispenser, a reflective dispenser, and a venturi dispenser.

[0007] Furthermore, the diameter of the pipes used in the flow path is between 4mm and 8mm.

[0008] Furthermore, the total length of the flow path is 7m-8m.

[0009] Furthermore, the gas collection pipe assembly includes a main pipe and a plurality of branch pipes, the plurality of branch pipes being arranged at intervals along the length direction of the main pipe; The two adjacent branch pipes are respectively connected to the third U-pipe and the fourth U-pipe.

[0010] Furthermore, the distributor assembly includes a plurality of diversion capillaries connected to the first U-tube.

[0011] Furthermore, the connecting pipe is a U-shaped pipe.

[0012] Furthermore, a cooling pipe is also provided at the bottom of the main body.

[0013] On the other hand, a heat pump unit is also provided, including: a finned heat exchanger as described above.

[0014] Furthermore, it also includes: a compressor, a plate heat exchanger, a throttling plate heat exchanger, a throttling assembly, and a four-way valve. One port of the compressor is connected to the four-way valve, and the four-way valve is connected to the other port of the compressor, the plate heat exchanger, and the gas collecting pipe assembly. The throttling plate heat exchanger and the throttling assembly are respectively disposed in the pipeline between the plate heat exchanger and the distributor assembly. The throttling plate heat exchanger is also connected to the compressor.

[0015] The beneficial effects of this application are as follows: a significant portion of the refrigerant becomes gaseous after heat exchange through multiple copper tubes at the front end, effectively reducing the refrigerant circulation pressure drop. Then, it forms a dual parallel channel through a three-way split at the rear end. While using small pipe diameters to enhance the heat transfer coefficient, it significantly reduces the refrigerant flow resistance, adapting to the stringent pressure drop control requirements of small-horsepower units. Moreover, it optimizes cost control, eliminating the need to increase the number of fin rows, avoiding the high cost defects of existing multi-row finned and single-inlet single-outlet flow paths, and reducing the unit design and manufacturing costs while ensuring performance. Attached Figure Description

[0016] The present application will now be described in further detail with reference to the accompanying drawings and embodiments.

[0017] Figure 1 This is a schematic diagram of the flow path of the finned heat exchanger described in the embodiments of this application; Figure 2 This is a schematic diagram of the heat pump unit described in the embodiments of this application.

[0018] In the diagram: 110, Finned heat exchanger; 1, Main body; 2, Gas collecting pipe assembly; 3, Distributor assembly; 4, Flow path; 401, First U-tube; 402, Connecting pipe; 403, Second U-tube; 404, Tee; 405, Third U-tube; 406, Fourth U-tube; 5, Subcooling pipe; 120. Compressor; 130. Plate heat exchanger; 140. Heat exchanger with increasing galvanic capacity; 150. Throttling assembly; 160. Four-way valve. Detailed Implementation

[0019] To make the technical problems solved by this application, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of this application are further described in detail below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0021] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0022] like Figure 1 As shown, this embodiment provides a finned heat exchanger, including: a body part 1, a gas collecting pipe assembly 2, a distributor assembly 3, and a plurality of flow paths 4. The plurality of flow paths 4 are respectively disposed on the body part 1, and one end of each flow path 4 is connected to the distributor assembly 3, and the other end is connected to the gas collecting pipe assembly 2. The flow path 4 includes a first U-tube 401, a connecting pipe 402, a second U-tube 403, a tee 404, a third U-tube 405, and a fourth U-tube 406. One end of the first U-tube 401 is connected to the distributor assembly 3, and the other end is connected to one end of the second U-tube 403 through the connecting pipe 402. The other end of the second U-tube 403 is connected to one port of the tee 404. The other two ports of the tee 404 are respectively connected to the third U-tube 405 and the fourth U-tube. The third U-tube 405 and the fourth U-tube 406 are also respectively connected to the gas collecting pipe assembly 2.

[0023] Based on the above scheme, the refrigerant is compressed into a high-temperature, high-pressure gaseous state by compressor 120, and then compressed into a low-temperature, low-pressure liquid refrigerant containing a small amount of gas after passing through condenser and throttling component 150. The refrigerant is then evenly distributed by distributor component 3. The refrigerant in each branch reaches the first U-tube 401, loops once, and then goes to connecting pipe 402. Connecting pipe 402 allows the refrigerant to pass through the second U-tube 403, loops once more, and then goes to tee 404. Through the structure of tee 404, it is split into the third U-tube 405 and the fourth U-tube 406, forming a dual-path parallel heat exchange channel at the rear. This design effectively... The increased refrigerant flow cross-sectional area reduces the frictional resistance generated by the high-speed flow of refrigerant under small pipe diameter, thus solving the core contradiction of increasing mass flow rate to enhance heat transfer and increasing pressure drop in existing technologies. At the same time, the combination design of four copper tubes at the front end and two U-tubes at the rear end can flexibly match the structural layout of two rows of fins. Through the reasonable combination of series and parallel, the total length of the single flow path 4 meets the requirement of refrigerant to fully exchange heat to the superheated state, while avoiding the problem of insufficient or excessive total length of the traditional flow path 4 under two rows of fins. Finally, after completing the heat exchange of the entire process, the refrigerant flows into the gas collecting pipe assembly 2 and returns to the compressor 120 through the four-way valve to complete the cycle.

[0024] In this process, a significant portion of the refrigerant becomes gaseous after heat exchange through four copper tubes. If it were still a single flow path 4, the resistance would be greater for the same copper tube diameter. If the refrigerant is diverted into two long U-tubes at this point, the refrigerant circulation pressure drop can be reduced until heat exchange is complete and the refrigerant reaches a superheated state, then proceeds to the gas collection pipe assembly 2, and finally enters the compressor 120 through a four-way valve for compression, completing the refrigerant circulation. Moreover, compared to the common single-inlet, single-outlet flow path 4, when a single tube exceeds one meter, if two rows are considered, each branch path may have four or eight copper tubes, resulting in either insufficient or excessive total length for a single flow path 4. Assuming three rows are considered, the cost increases for small-horsepower machines, and there is too much margin. This solution considers cost without increasing the number of rows, rationally sets the total length of each branch path to ensure sufficient heat exchange for the refrigerant, and the presence of four copper tubes at the front end reduces the number of liquid distribution holes, resulting in more even refrigerant distribution. The two-way diversion at the rear end reduces the pressure drop, allowing the entire finned system to achieve better energy efficiency.

[0025] Optionally, the distributor assembly 3 includes one of a conical distributor, a reflective distributor, and a Venturi distributor. The conical distributor uses the guiding effect of its internal conical surface to ensure uniform diffusion of the throttled gas-liquid two-phase refrigerant along the conical wall. Utilizing the coupling effect of centrifugal force and gravity, it distributes the refrigerant to each output channel, avoiding uneven distribution caused by gas-liquid stratification. The reflective distributor uses an internal reflector to change the refrigerant flow direction, causing the refrigerant to impact the reflector and form a uniform jet field. The refrigerant is then distributed through symmetrically arranged output ports, adapting to the precise distribution requirements under low-flow conditions.

[0026] In a preferred embodiment, a Venturi distributor is used. This preferred Venturi distributor, with its classic constriction-throat-expansion structure, works in conjunction with the front-end design of flow path 4 in this application to form a synergistic pressure reduction and uniform liquid distribution mechanism. The throttled gas-liquid two-phase refrigerant first enters the constriction section of the distributor, where the reduced cross-sectional area gradually increases the refrigerant velocity. At the throat, the velocity reaches its maximum, and the resulting negative pressure environment enhances the turbulent mixing of the gas and liquid phases, preventing increased local flow resistance due to gas-liquid stratification. Subsequently, the refrigerant enters the expansion section, where the cross-sectional area gradually increases, the velocity slowly decreases, and the pressure gradually stabilizes. Simultaneously, through the symmetrically arranged outlets at the end of the expansion section, the uniformly mixed refrigerant is precisely distributed to the four copper tubes connected in series in the front-end flow path 4. During this process, the Venturi structure achieves efficient liquid distribution while minimizing the local resistance loss of the refrigerant in the distributor through flow control of acceleration-stabilization-pressure reduction, directly reducing the pressure drop of the refrigerant at the front end. It is also compatible with the flow path 4 design of this application, which reduces the number of liquid distribution holes, and further avoids the additional flow resistance caused by multiple liquid distribution holes.

[0027] Furthermore, the pipe diameter used in flow path 4 is between 4mm and 8mm. The selection of 4mm-8mm pipe diameter for flow path 4 is based on a balanced design between heat exchange performance and pressure drop control for small-horsepower units. Its core principle is deeply compatible with the front-end series heat exchange and rear-end diversion pressure reduction flow path 4 structure of this application, specifically 5mm or 7mm. A 5mm pipe diameter, as a representative of small pipe diameters, allows for increased mass flow velocity within the pipe at the same refrigerant flow rate due to its smaller cross-sectional area. According to heat transfer principles, increased flow velocity enhances the convective heat transfer coefficient within the pipe, improving the initial heat exchange effect of the four copper pipes in series at the front end. Simultaneously, the dual parallel channels formed by the rear-end 404 tee diversion can offset the pressure drop increase caused by the small pipe diameter, preventing the total system pressure drop from exceeding limits.

[0028] Compared to 5mm pipe diameter, 7mm pipe diameter has a larger flow cross-sectional area. While ensuring a certain mass flow rate to maintain the heat transfer coefficient, it can significantly reduce the resistance along the flow path of the refrigerant, making it especially suitable for small-horsepower units that are more sensitive to pressure drop. Furthermore, the combination of 7mm pipe diameter and the total length of flow path 4 can reduce the number of flow paths 4 while ensuring that the refrigerant can fully exchange heat to a superheated state, avoiding the decrease in heat exchange efficiency caused by excessively large pipe diameter.

[0029] In addition, the 4mm-8mm pipe diameter range provides an adaptation range for different operating conditions. Both specific pipe diameters can work in synergy with the liquid distribution characteristics and fin arrangement of the distributor assembly 3, taking into account both heat transfer enhancement and pressure drop control.

[0030] Furthermore, the total length of the flow path 4 is 7m-8m. This solution precisely solves the problem of adapting the total length of the two-row finned flow path 4, directly avoiding the problems of insufficient heat exchange due to excessively short total length or excessive pressure drop due to excessively long total length in single-inlet single-outlet designs. With the two-row finned layout, it achieves the dual goals of sufficient heat exchange path and controllable flow resistance, ensuring the heat exchange requirements of the refrigerant throughout the entire process from liquid to superheated gas.

[0031] For small pipe diameters of 5mm / 7mm, a total length of 7m-8m can be kept within a reasonable mass flow rate range to avoid excessive pressure drop caused by high flow rate. By extending the heat exchange time, the insufficient heat exchange area of ​​a single small pipe is compensated to ensure that the overall heat exchange is not lower than that of a large-diameter long flow path design.

[0032] In some embodiments, the gas collection pipe assembly 2 includes a main pipe and several branch pipes, which are spaced apart along the length of the main pipe. Two adjacent branch pipes are connected to the third U-pipe 405 and the fourth U-pipe 406, respectively. The superheated gaseous refrigerant output from the rear third U-pipe 405 and fourth U-pipe 406 enters the adjacent branch pipes spaced apart along the length of the main pipe in the gas collection pipe assembly 2. Because the two branch pipes are spaced apart, the two refrigerant streams can converge synchronously from different axial positions in the main pipe, avoiding eddies and pressure losses caused by direct collision of the two airflows at the same cross-section. Simultaneously, the spaced branch pipes create a distributed convergence path for the refrigerant along the length of the main pipe. The refrigerant can gradually merge within the main pipe through axial diffusion and radial mixing, rather than concentrating violently at a single point, thus ensuring stable pressure and uniform flow rate during the merging process and avoiding additional pressure drops or airflow pulsations due to improper merging.

[0033] Meanwhile, the distributor assembly 3 includes several diversion capillary tubes, which are connected to the first U-tube 401. A transition tube is also sleeved between the diversion capillary tubes and the first U-tube 401. Utilizing the throttling and distribution characteristics of its narrow diameter structure, the diversion capillary tubes receive the uniform gas-liquid mixture refrigerant output from the Venturi distributor. Through the flow-limiting effect of the capillary tubes, the refrigerant is further precisely distributed to the first U-tube 401 of each flow path 4. Each branch capillary corresponds to a first U-tube 401. Through precise matching of the capillary's inner diameter and length, equal distribution of refrigerant flow is achieved in each flow path 4, avoiding flow deviations caused by differences in flow path 4 resistance. A transition tube fitted between the branch capillary and the first U-tube 401 serves to adapt the tube diameter and ensure a smooth flow transition. This is because the branch capillary's diameter is typically smaller than the first U-tube 401. The transition tube employs a gradually changing inner diameter structure, allowing the cross-sectional area of ​​the flow channel to expand smoothly after the refrigerant flows out of the capillary, avoiding abrupt changes in the flow channel caused by direct connection, thereby reducing local eddies and resistance losses. Simultaneously, the tight-fitting installation of the transition tube ensures a tight seal between the capillary and the first U-tube 401, preventing refrigerant leakage or external air infiltration, and guaranteeing the airtightness and heat exchange stability of the flow path 4 system.

[0034] Specifically, the connecting pipe 402 is a U-shaped pipe, which can also be understood as a short U-shaped pipe. The smooth turn of the U-shaped structure avoids the local eddies and resistance surges caused by right-angle bends or long pipe turns. The short length design reduces the friction resistance of the refrigerant flowing through the connecting pipe 402, forming a full-process pressure reduction synergy with the Venturi distributor, the diversion capillary tube, and the dual-path diversion at the rear end, further optimizing the system pressure drop of small-horsepower units. Moreover, the short U-shaped pipe achieves pipe turning without adding extra length to the front-end series section, ensuring that the refrigerant maintains a reasonable mass flow rate and heat exchange time throughout the flow process of the first U-shaped pipe 401 - short U-shaped pipe - second U-shaped pipe 403, laying a sufficient gas-liquid conversion foundation for the subsequent tee 404 diversion and dual-path heat exchange, and avoiding heat exchange path imbalance caused by excessive length of the connecting pipe 402.

[0035] Generally, a subcooling pipe 5 is also provided at the bottom of the main body 1. In the heating cycle of the heat pump unit, the high-pressure liquid refrigerant condensed by the condenser first flows through the subcooling pipe 5 at the bottom of the main body 1. At this time, the main flow path 4 of the main body 1 is absorbing low-grade heat energy from the air through the fins, so that a stable low-temperature environment is formed around the main body 1. The subcooling pipe 5 uses this low-temperature environment to exchange heat with the liquid refrigerant inside the pipe, further reducing the temperature of the refrigerant to below the saturation temperature, forming a subcooled refrigerant. The subcooled refrigerant then enters the throttling component 150 for throttling, and is converted into a low-temperature, low-pressure liquid refrigerant containing a small amount of gas. Subsequently, it enters the distributor component 3 to complete the liquid distribution. In this design, the subcooling pipe 5 utilizes the existing low-temperature field of the main body 1 to achieve the subcooling function without the need for additional refrigeration or heat exchange mechanisms. Furthermore, the bottom installation method avoids heat exchange interference with the main flow path 4. At the same time, the flash gas content of the refrigerant is significantly reduced after subcooling, and the gas-liquid two-phase flow is more stable. This allows it to work synergistically with the two-stage liquid distribution structure of the Venturi distributor and the split capillary, avoiding liquid distribution deviation and increased flow resistance caused by flash gas.

[0036] On the other hand, such as Figure 2 As shown, a heat pump unit is also provided, including: a finned heat exchanger 110 as described above.

[0037] Furthermore, it also includes: a compressor 120, a plate heat exchanger 130, a throttling plate heat exchanger 140, a throttling assembly 150, and a four-way valve. One port of the compressor 120 is connected to the four-way valve, and the four-way valve is connected to the other port of the compressor 120, the plate heat exchanger 130, and the gas collecting pipe assembly 2. The throttling plate heat exchanger 140 and the throttling assembly 150 are respectively disposed in the pipeline between the plate heat exchanger 130 and the distributor assembly 3. The throttling plate heat exchanger 140 is also connected to the compressor 120.

[0038] Based on the above scheme, the main process of the heating cycle is as follows: The high-temperature and high-pressure gaseous refrigerant discharged from the compressor 120 is guided by a four-way valve to the plate heat exchanger 130, which is a condenser at this time. After heat exchange with the water side or other heat exchange media, it condenses into high-pressure liquid refrigerant; the liquid refrigerant enters the anodic plate heat exchanger 140 and undergoes secondary heat exchange with the low-temperature gaseous refrigerant at the suction end of the compressor 120, further increasing the subcooling degree and forming anodic subcooling; then it is throttled and depressurized by the throttling component 150 and converted into low-temperature and low-pressure liquid refrigerant containing a small amount of gas; the refrigerant enters the distributor component 3 of the finned heat exchanger 110, and after two-stage liquid separation, it enters the flow path 4 to complete evaporation and heat absorption, and is converted into superheated gaseous refrigerant; finally, after being smoothly merged by the gas collecting pipe component 2, it returns to the suction end of the compressor 120 through the four-way valve to complete the cycle.

[0039] The Zenghan plate heat exchanger 140 enhances the subcooling of the condensing refrigerant and preheats the suction refrigerant through heat exchange between the condensing and suction refrigerants, thereby reducing the compression power consumption of the compressor 120. The throttling component 150 is adapted to the 5mm / 7mm small pipe diameter and 7m-8m flow path 4 of the finned heat exchanger 110 to ensure stable refrigerant flow after throttling. The four-way valve realizes the switching of circulation direction, and its interface layout matches the pipeline connection of the compressor 120, plate heat exchanger 130, and finned heat exchanger 110 to ensure small pressure fluctuations when the refrigerant switches directions.

[0040] In the description herein, it should be understood that the terms "upper," "lower," "left," "right," and other orientations or positional relationships are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used merely for descriptive distinction and have no special meaning.

[0041] In the description of this specification, references to terms such as "an embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0042] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0043] The technical principles of this application have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of this application without inventive effort, and these embodiments will all fall within the scope of protection of this application.

Claims

1. A finned heat exchanger, characterized in that, include: The body (1), the gas collection pipe assembly (2), the distributor assembly (3) and a plurality of flow paths (4) are respectively provided on the body (1), and one end of the flow path (4) is connected to the distributor assembly (3) and the other end is connected to the gas collection pipe assembly (2); The flow path (4) includes a first U-tube (401), a connecting pipe (402), a second U-tube (403), a tee (404), a third U-tube (405), and a fourth U-tube (406). One end of the first U-tube (401) is connected to the distributor assembly (3), and the other end is connected to one end of the second U-tube (403) through the connecting pipe (402). The other end of the second U-tube (403) is connected to one port of the tee (404). The other two ports of the tee (404) are respectively connected to the third U-tube (405) and the fourth U-tube. The third U-tube (405) and the fourth U-tube (406) are also respectively connected to the gas collecting pipe assembly (2).

2. The finned heat exchanger according to claim 1, characterized in that, The dispenser assembly (3) includes one of a conical dispenser, a reflective dispenser, and a venturi dispenser.

3. The finned heat exchanger according to claim 1 or 2, characterized in that, The diameter of the pipe used in the flow path (4) is between 4mm and 8mm.

4. The finned heat exchanger according to claim 1 or 2, characterized in that, The total length of the flow path (4) is 7m-8m.

5. The finned heat exchanger according to claim 1 or 2, characterized in that, The gas collection pipe assembly (2) includes a main pipe and several branch pipes, with the branch pipes arranged at intervals along the length of the main pipe. The two adjacent branch pipes are respectively connected to the third U-pipe (405) and the fourth U-pipe (406).

6. The finned heat exchanger according to claim 1 or 2, characterized in that, The distributor assembly (3) includes a plurality of shunt capillaries connected to the first U-tube (401).

7. The finned heat exchanger according to claim 1 or 2, characterized in that, The connecting pipe (402) is a U-shaped pipe.

8. The finned heat exchanger according to claim 1 or 2, characterized in that, The bottom of the main body (1) is also provided with a cooling pipe (5).

9. A heat pump unit, characterized in that, include: The finned heat exchanger (110) as described in any one of claims 1-8.

10. The heat pump unit according to claim 9, characterized in that, Also includes: The compressor (120), plate heat exchanger (130), throttling plate heat exchanger (140), throttling assembly (150), and four-way valve are provided. One port of the compressor (120) is connected to the four-way valve. The four-way valve is connected to the other port of the compressor (120), the plate heat exchanger (130), and the gas collecting pipe assembly (2). The throttling plate heat exchanger (140) and the throttling assembly (150) are respectively arranged in the pipeline between the plate heat exchanger (130) and the distributor assembly (3). The throttling plate heat exchanger (140) is also connected to the compressor (120).

Images