Air side heat exchanger, refrigerant circulation system, defrosting control method and air conditioner

Abstract

The invention provides an air side heat exchanger, a refrigerant circulation system, a defrosting control method and an air conditioner, and relates to the technical field of refrigeration equipment, the air side heat exchanger comprises an upper subarea, a lower subarea, an air collecting pipe and an on-off valve, and the upper subarea comprises a plurality of first branch pipes arranged side by side; the lower partition comprises a plurality of second branch pipes which are arranged in parallel; the gas collecting pipe is connected with the plurality of first branch pipes and the plurality of second branch pipes, and the output end of the gas collecting pipe is directly connected with the lower subarea; the on-off valve is arranged on the gas collecting pipe and used for controlling communication or isolation of the upper subarea and the lower subarea. And when the air side heat exchanger performs defrosting, the on-off valve is opened. When defrosting of the upper subarea is completed, the on-off valve in the middle of the gas collecting pipe is closed, high-temperature refrigerants enter the lower subarea in a concentrated mode, invalid work is not conducted on the upper subarea without a frost layer any more, the frost layer on the surface of the heat exchanger on the lower portion is rapidly and efficiently melted, the heat exchange effect of the air side heat exchanger is good, a compressor is not prone to being damaged, and the service life is long.

Description

Technical Field

[0001] This invention relates to the field of refrigeration equipment technology, and in particular to an air-side heat exchanger, a refrigerant circulation system, a defrosting control method, and an air conditioner. Background Technology

[0002] Air source heat pumps, as a primary method of winter heating in non-centralized heating areas, are widely accepted and extensively applied due to their energy efficiency and cost-effectiveness. However, due to the inherent characteristics of air source heat pumps, when heating is required in ambient temperatures below 10°C, evaporative frosting inevitably occurs on the finned coil heat exchanger on the air source side. As the frost layer thickens, the heat exchange efficiency drops sharply, necessitating defrosting at appropriate times. Current defrosting methods primarily involve the entire system operating in reverse circulation, with hot refrigerant directly entering the outdoor air-side heat exchanger to remove the frost layer. Extensive experimental verification under various environmental conditions has identified the complete defrosting process as determined by the outlet temperature of one of the heat exchanger's circuits. Once defrosting is complete, the system switches to the heating cycle for heating.

[0003] In actual defrosting, the temperature of the bottom heat exchanger circuit is usually difficult to rise to the defrost exit temperature point. Therefore, the representative circuits obtained from experiments are all bottom circuits, while the upper heat exchanger part has already defrosted. The bottom pipe temperature is slow to rise, causing other protection conditions to be triggered. The commonly used exit protection mechanism is that the system high pressure reaches the protection disconnect value, and defrosting must be stopped, otherwise the compressor will be damaged. In fact, defrosting is not completely thorough. After one incomplete defrosting, after multiple heating-defrosting-heating-defrosting cycles, the unclean frost layer accumulates into ice, eventually causing the heat exchange effect of the air source heat exchanger to become worse and worse, the evaporation heat absorption is incomplete, the unit operates at a low pressure, the operating pressure ratio increases, and the power consumption and reliability all become worse. Moreover, the bottom pipe temperature is also very easy to reach the defrost trigger condition, causing frequent defrosting, resulting in a worse and worse heating effect. In addition, the defrost exit in this process often triggers the high pressure protection, which will inevitably lead to compressor damage in the long run.

[0004] In view of this, a new technical solution is needed to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide an air-side heat exchanger, a defrosting method, and an air conditioner, which have stable and reliable heat exchange effects and long compressor service life, in order to solve the problems of increasingly poor heat exchange effects of heat exchangers and easy damage to compressors.

[0006] To achieve the above objectives, the present invention employs the following technical means:

[0007] A first aspect of the present invention provides an air-side heat exchanger, comprising:

[0008] The upper section includes multiple first branches arranged in parallel;

[0009] The lower section is located below the upper section in the direction of gravity, and the lower section includes a plurality of second branch pipes arranged in parallel.

[0010] A gas collecting pipe is connected to multiple first branch pipes and multiple second branch pipes, and the output end of the gas collecting pipe is directly connected to the lower partition.

[0011] An on / off valve, located on the gas collection pipe, is used to control the connection or isolation between the upper and lower partitions.

[0012] Optionally, the air-side heat exchanger has a first operating mode and a second operating mode, and can switch between the first operating mode and the second operating mode;

[0013] In the first operating mode, the on / off valve is open to allow refrigerant to be input through the gas collection pipe, and then enter the upper and lower partitions through the gas collection pipe; in the second operating mode, the on / off valve is closed to isolate the upper and lower partitions from each other, and the refrigerant is input only from the output end of the gas collection pipe, and then passes through the lower partition.

[0014] Optionally, the system also includes a distributor, which is connected to the upper partition by a plurality of first branches, each of which is connected to a first branch pipe in a one-to-one correspondence; and the distributor is connected to the lower partition by a plurality of second branches, each of which is connected to a second branch pipe in a one-to-one correspondence.

[0015] Optionally, the system further includes a control module, a first temperature sensor, and a second temperature sensor. The first temperature sensor is located on the first branch pipe and is used to acquire the surface temperature T1 of the upper partition. The second temperature sensor is located on the second branch pipe and is used to acquire the surface temperature T2 of the lower partition. The control module is used to control the on-off valve to close when the surface temperature T1 of the upper partition is continuously detected by Δtsmin ≥ the preset defrosting end temperature Ts, and to control the on-off valve to open when the surface temperature T2 of the lower partition is continuously detected by Δtsmin ≥ the preset defrosting end temperature Ts. Here, Δtsmin represents the minimum detection time.

[0016] Optionally, the on / off valve is an electric ball valve.

[0017] A second aspect of the present invention provides a refrigerant circulation system comprising any of the air-side heat exchangers described above.

[0018] Optionally, it includes a refrigerant circulation loop, which is equipped with a compressor, a user-side heat exchanger, a throttling mechanism, an air-side heat exchanger four-way valve, and an outdoor fan. The four-way valve is located between the compressor and the user-side heat exchanger, and the air-side heat exchanger is located inside the outdoor fan.

[0019] Optionally, it also includes a gas-liquid separator disposed between the compressor and the air-side heat exchanger.

[0020] A third aspect of the present invention provides a defrosting control method for any of the above-described refrigerant circulation systems, comprising:

[0021] During the heating cycle, the electric ball valve is kept in the open position.

[0022] When Δtkmin continuously detects that both T1 and T2 are less than the preset defrosting start temperature Tk, the throttling mechanism is adjusted to the preset defrosting position, the four-way valve is switched to the defrosting state, and the outdoor fan is controlled to stop running and enter the defrosting operation state.

[0023] When Δtsmin continuously detects that T1 ≥ preset defrosting end temperature Ts, the electric ball valve is controlled to close.

[0024] When Δtsmin continuously detects that T2 ≥ preset defrosting end temperature Ts, the electric ball valve is opened, the four-way valve is switched to heating operation mode, the outdoor fan is started, the throttling mechanism is adjusted to the heating operation position, and defrosting is completed.

[0025] A fourth aspect of the present invention provides an air conditioner comprising any of the refrigerant circulation systems described above.

[0026] Compared with existing technologies, the present invention brings the following technical effects:

[0027] The air-side heat exchanger of this invention includes an upper section and a lower section, both connected to a gas collecting pipe. A channel valve is provided on the gas collecting pipe to control the connection between the upper and lower sections. When the air-side heat exchanger is defrosting, the on / off valve is opened to allow refrigerant to pass through the upper and lower sections. When the upper section has finished defrosting, the on / off valve in the middle of the gas collecting pipe is closed, allowing the high-temperature refrigerant to concentrate in the lower section, thus preventing ineffective work on the upper section where there is no frost and quickly and efficiently melting the frost layer on the surface of the lower heat exchanger. The air-side heat exchanger has good heat exchange performance; the lower section receives concentrated heat exchange, preventing frequent defrosting that could trigger low-pressure protection, reducing compressor damage, and extending service life. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic diagram of the structure of an air-side heat exchanger according to some embodiments of the present invention is shown;

[0030] Figure 2 A schematic diagram illustrating the heating cycle state of a refrigerant circulation system according to some embodiments of the present invention is shown.

[0031] Figure 3 A schematic diagram illustrating the defrosting cycle state of a refrigerant circulation system according to some embodiments of the present invention is shown.

[0032] Figure 4 A schematic flowchart of a defrosting method according to some embodiments of the present invention is shown.

[0033] Explanation of key component symbols:

[0034] 10-Compressor; 20-Usage-side heat exchanger; 30-Throttling mechanism; 40-Air-side heat exchanger; 41-Distributor; 42-Upper section; 421-First branch pipe; 43-Lower section; 431-Second branch pipe; 44-Gas collection pipe; 441-First branch; 442-Second branch; 45-Electric ball valve; 46-First temperature sensor; 47-Second temperature sensor; 50-Gas-liquid separator; 60-Four-way valve; 70-Outdoor fan. Detailed Implementation

[0035] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0037] Please see Figure 1In a first aspect, the present invention provides an air-side heat exchanger 40, comprising: an upper section 42, a lower section 43, an air collecting pipe 44, and an on / off valve. The upper section 42 includes a plurality of first branch pipes 421 arranged in parallel. The lower section 43 is located below the upper section 42 in the direction of gravity and includes a plurality of second branch pipes 431 arranged in parallel. The air collecting pipe 44 is connected to the plurality of first branch pipes 421 and to the plurality of second branch pipes 431, and the output end of the air collecting pipe 44 is directly connected to the lower section 43. The on / off valve is provided on the air collecting pipe 44 for controlling the connection or isolation between the upper section 42 and the lower section 43.

[0038] The air-side heat exchanger 40 of the present invention includes an upper section 42 and a lower section 43, both of which are connected to a gas collecting pipe 44. A channel valve is provided on the gas collecting pipe 44 to control the connection between the upper section 42 and the lower section 43. When the air-side heat exchanger 40 defrosts, the on / off valve is opened to allow refrigerant to pass through the upper section 42 and the lower section 43. When the upper section 42 has finished defrosting, the on / off valve in the middle of the gas collecting pipe 44 is closed, allowing the high-temperature refrigerant to concentrate in the lower section 43, thus eliminating ineffective work on the upper section 42 which is no longer frost-free, and quickly and efficiently melting the frost layer on the lower heat exchanger surface. The air-side heat exchanger 40 has good heat exchange performance; the lower section 43 receives concentrated heat exchange, preventing frequent defrosting and triggering low-pressure protection, reducing the risk of damage to the compressor 10, and extending its service life.

[0039] Figure 1 The direction of the middle arrow indicates one of the flow directions of the refrigerant in the air-side heat exchanger 40.

[0040] Understandably, by modularly configuring the upper section 42 and lower section 43 of the air-side heat exchanger 40, and then controlling the disconnection between the upper section 42 and lower section 43 via on / off valves, the refrigerant is concentrated to flow through the lower section 43, thereby improving the heat exchange efficiency of the lower section 43. The control-side heat exchanger is located in the outdoor fan 70 and needs to be exposed to the low-temperature environment of the outside. Specifically, the on / off valve is located between the lowermost first branch pipe 421 and the uppermost second branch pipe 431.

[0041] In a conventional air-side heat exchanger 40, the refrigerant flows through multiple branch pipes on average. In practical application, the inventors observed that the upper section 42 of the air-side heat exchanger 40 has a relatively higher heat exchange efficiency, while the lower section 43 has a lower efficiency. Analysis of the above technical issues revealed the following three reasons:

[0042] Firstly, during the defrosting process, the high-temperature gaseous refrigerant flows upward from the bottom of the manifold 44 and enters the branch circuit from the branch pipe. At the beginning of defrosting, because there is still a lot of liquid refrigerant in the branch pipe, the resistance is relatively large. Therefore, the branch pipe near the bottom of the manifold naturally receives less refrigerant, and more high-temperature gaseous refrigerant enters the upper section 42, resulting in a faster and more efficient defrosting speed in the upper section 42.

[0043] Secondly, as defrosting proceeds, the defrosting water on the surface of the upper section 42 of the heat exchanger will flow downwards and pass through the surface of the lower section 43 of the heat exchanger. Since water has a high specific heat capacity, the heat on the surface of the lower section 43 will be carried away by this water and cannot be used entirely for defrosting.

[0044] Thirdly, after defrosting of the upper section 42, the inside of the branch pipe is full of gaseous refrigerant, and the flow resistance is small, which causes the gaseous refrigerant to pass through the upper section 42 quickly. Because the flow resistance is small, more refrigerant will flow through that flow path.

[0045] Based on the above reasons, the air-side heat exchanger 40 has an upper section 42 and a lower section 43 with significant differences in heat exchange efficiency. Its principle is fundamentally different from that of the uneven heat exchange of multiple branch pipes in a shell-and-tube heat exchanger.

[0046] It should be noted that the lower section 43 is located below the upper section 42 in the direction of gravity. The high-temperature gaseous refrigerant flows upward from the bottom of the gas collecting pipe 44, while the defrosting water on the surface of the upper section 42 of the heat exchanger flows downward. This is why there is a significant difference in heat exchange efficiency between the upper section 42 and the lower section 43, with the lower section 43 exhibiting insufficient heat exchange efficiency.

[0047] In this embodiment, the upper section 42 includes four first branch pipes 421, and the lower section 43 includes four second branch pipes 431. The scope of protection of the present invention is not limited to the specific number of the first branch pipes 421 and the second branch pipes 431.

[0048] Combination Figure 2 and Figure 3 , Figure 2 The direction of the solid arrow indicates the direction of refrigerant flow. Figure 3 The direction of the dashed arrow indicates the direction of refrigerant flow. The air-side heat exchanger 40 has a first operating mode and a second operating mode, and can switch between the first operating mode and the second operating mode;

[0049] Specifically, in the first working mode, the on / off valve is open so that the refrigerant is input through the gas collection pipe 44 and then enters the upper partition 42 and the lower partition 43 through the gas collection pipe 44; in the second working mode, the on / off valve is closed so that the upper partition 42 and the lower partition 43 are isolated from each other, and the refrigerant is only input from the output end of the gas collection pipe 44 and then passes through the lower partition 43.

[0050] Understandably, the air-side heat exchanger 40 is used in the refrigerant circulation system. The refrigerant circulation system has a heating cycle mode and a defrosting cycle mode. Switching between the first and second operating modes on the air side is only controlled in the defrosting cycle mode.

[0051] The air side can be switched between the first and second operating modes simply by opening or closing the on / off valve. The operation is simple and highly interactive.

[0052] In one specific embodiment, it also includes a distributor 41, which is connected to the upper partition 42 by a plurality of first branches 441, and the first branches 441 are connected to the first branch pipes 421 in a one-to-one correspondence; the distributor 41 is connected to the lower partition 43 by a plurality of second branches 442, and the second branches 442 are connected to the second branch pipes 431 in a one-to-one correspondence.

[0053] The distributor 41 has one input port and multiple output ports, each corresponding to either a first branch 441 or a second branch 442. By configuring the distributor 41, the refrigerant can be converted from a single flow to multiple flows, allowing the refrigerant to enter the first branch pipe 421 or the second branch pipe 431, thereby increasing the contact area between the refrigerant and the heat exchanger and improving the heat exchange efficiency. Alternatively, the distributor 41 can merge multiple refrigerant flows into a single flow.

[0054] Please refer to it again. Figure 1 In one specific embodiment, the air-side heat exchanger 40 further includes a control module, a first temperature sensor 46, and a second temperature sensor 47. The first temperature sensor 46 is located on the first branch pipe 421 and is used to obtain the surface temperature T1 of the upper partition 42. The second temperature sensor 47 is located on the second branch pipe 431 and is used to obtain the surface temperature T2 of the lower partition 43. The control module is used to control the on-off valve to close when the surface temperature T1 of the upper partition 42 is continuously detected by Δtsmin ≥ the preset defrosting end temperature Ts, and to control the on-off valve to open when the surface temperature T2 of the lower partition 43 is continuously detected by Δtsmin ≥ the preset defrosting end temperature Ts.

[0055] It is understandable that the on / off valve is an actuator used to receive and respond to signals output by the control module to open or close. Δtsmin characterizes the minimum detection time;

[0056] By setting up a control module, a first temperature sensor 46, and a second temperature sensor 47, and by connecting the control module to the first temperature sensor 46, the second temperature sensor 47, and the on / off valve, the automated control of the on / off valve is achieved, thereby improving the automation and intelligence of the air-side heat exchanger 40.

[0057] In one specific embodiment, the on / off valve is an electric ball valve 45.

[0058] The electric ball valve 45 can be used with the control module for automatic remote control, with fast response speed and more precise positioning of the opening degree.

[0059] Please see Figure 2 and Figure 3 In a second aspect, the present invention provides a refrigerant circulation system including any of the above-mentioned air-side heat exchangers 40.

[0060] The refrigerant circulation system of this embodiment includes the air-side heat exchanger 40 of any of the above embodiments. The air-side heat exchanger 40 of this invention includes an upper section 42 and a lower section 43, both of which are connected to a gas collecting pipe 44. A channel valve is provided on the gas collecting pipe 44 to control the connection between the upper section 42 and the lower section 43. When the air-side heat exchanger 40 defrosts, the on / off valve is opened to allow refrigerant to pass through the upper section 42 and the lower section 43. When the upper section 42 has finished defrosting, the on / off valve in the middle of the gas collecting pipe 44 is closed, allowing the high-temperature refrigerant to concentrate in the lower section 43, thus eliminating the need for ineffective work on the upper section 42, which is now free of frost, and quickly and efficiently melting the frost layer on the surface of the lower heat exchanger. The air-side heat exchanger 40 has good heat exchange effect, and the lower section 43 receives concentrated heat exchange, preventing frequent defrosting and triggering of low-pressure protection. The compressor 10 is less prone to damage and has a long service life. The refrigerant circulation system has high defrosting efficiency and strong operational stability.

[0061] In one specific embodiment, it includes a refrigerant circulation loop, on which a compressor 10, a user-side heat exchanger 20, a throttling mechanism 30, an air-side heat exchanger 40, a four-way valve 60, and an outdoor fan 70 are provided. The four-way valve 60 is located between the compressor 10 and the user-side heat exchanger 20, and the air-side heat exchanger 40 is located inside the outdoor fan 70.

[0062] The refrigerant circulation loop has a heating circulation mode and a defrosting circulation mode, and can switch between the two modes.

[0063] In heating cycle mode, compressor 10 draws in low-pressure superheated refrigerant vapor from air-side heat exchanger 40, compresses it into high-temperature and high-pressure superheated vapor, and enters the user-side heat exchanger 20 through four-way valve 60. The air (or water) flowing through user-side heat exchanger 20 absorbs heat from the refrigerant and heats up to achieve the purpose of heating. Meanwhile, the refrigerant in user-side heat exchanger 20 releases heat and condenses into subcooled refrigerant liquid, which flows into air-side heat exchanger 40 after being throttled and depressurized by electronic expansion valve.

[0064] After absorbing heat from the outdoor ambient air, the refrigerant vaporizes into low-pressure superheated refrigerant vapor, which flows into the gas-liquid separator after passing through the four-way valve 60. The gas-liquid separator 50 separates the incompletely evaporated liquid refrigerant from the gaseous refrigerant (the liquid refrigerant remains at the bottom of the separator), and the gaseous refrigerant is then drawn into the compressor 10 for compression, starting a new cycle.

[0065] During the defrosting cycle, compressor 10 draws in low-pressure superheated refrigerant vapor from the heat exchanger on the user side. The compressor 10 compresses the vapor into high-temperature, high-pressure superheated vapor, which then enters the air-side heat exchanger 40 through the four-way valve 60 to dissipate heat onto the surface of the heat exchanger, melting the frost layer on the surface. The refrigerant then condenses into subcooled liquid refrigerant, which flows into the user-side heat exchanger 20 after being throttled and depressurized by the electronic expansion valve. There, it absorbs heat from the air (or water) flowing through the user-side heat exchanger 20 and vaporizes into low-pressure superheated refrigerant vapor, which is then drawn in and compressed by compressor 10 to begin a new defrosting cycle.

[0066] It should be noted that the four-way valve 60 has four connection terminals: S, E, D, and C. In heating cycle mode, terminals S and C of the four-way valve 60 are connected, and terminals D and E are connected. In defrost cycle mode, the four-way valve 60 switches to a configuration where terminals S and E are connected, and terminals C and D are connected.

[0067] In one specific embodiment, the refrigerant circulation loop further includes a gas-liquid separator 50, which is disposed between the compressor 10 and the air-side heat exchanger 40.

[0068] The gas-liquid separator 50 separates liquid and gaseous refrigerant through its internal structure, ensuring that the compressor 10 draws in gaseous refrigerant while the liquid refrigerant remains at the bottom of the separator. Since liquid is an incompressible fluid, its entry into the compressor 10 would cause liquid slugging and damage. The gas-liquid separator 50 significantly improves the operational stability of the compressor 10.

[0069] Please see Figures 1-4 A third aspect of the present invention provides a defrosting control method for any of the above-mentioned refrigerant circulation systems, comprising:

[0070] The first temperature sensor 46 acquires the surface temperature in the upper partition 42, and the second temperature sensor acquires the surface temperature in the lower partition 43.

[0071] S10: In the heating cycle state, control the electric ball valve 45 to be in the open state;

[0072] S20: When Δtkmin continuously detects that T1 and T2 are both < preset defrosting start temperature Tk, adjust the throttling mechanism 30 to the preset defrosting position, switch the four-way valve 60 to the defrosting state, and control the outdoor fan 70 to stop running and enter the defrosting operation state.

[0073] S30: When Δtsmin continuously detects that T1 ≥ preset defrosting end temperature Ts, control the electric ball valve 45 to close;

[0074] S40: When Δtsmin continuously detects that T2 ≥ the preset defrosting end temperature Ts, the electric ball valve 45 is opened, the four-way valve 60 is switched to heating operation, the outdoor fan 70 is started, the throttling mechanism 30 is adjusted to the heating operation position, and defrosting is completed. T1 is the temperature of the upper zone 42 detected by the first temperature sensor 46, T2 is the temperature of the lower zone 43 detected by the second temperature sensor 47, and Δtsmin represents the minimum detection time.

[0075] By using two temperature sensors in conjunction with the electric ball valve 45, the refrigerant flow during the defrosting process is utilized more efficiently. In the later stages of defrosting, a large amount of high-heat refrigerant is concentrated and flows to the heat exchanger at the bottom, increasing the refrigerant flow by nearly double and quickly completing the defrosting of the bottom.

[0076] In a fourth aspect, the present invention provides an air conditioner comprising any of the above-mentioned refrigerant circulation systems.

[0077] The air conditioner in this embodiment employs any of the aforementioned refrigerant circulation systems. This system includes an air-side heat exchanger 40, with its upper section 42 and lower section 43 both connected to a gas collection pipe 44. A channel valve is installed on the gas collection pipe 44 to control the connection between the upper section 42 and the lower section 43. When the air-side heat exchanger 40 defrosts, the on / off valve is opened to allow refrigerant to pass through the upper section 42 and the lower section 43. When the upper section 42 has finished defrosting, the on / off valve in the middle of the gas collection pipe 44 is closed, allowing the high-temperature refrigerant to concentrate in the lower section 43. This prevents unnecessary work on the upper section 42, which is now free of frost, and quickly and efficiently melts the frost layer on the surface of the lower heat exchanger. The air-side heat exchanger 40 has good heat exchange efficiency, and the lower section 43 receives concentrated heat exchange, preventing frequent defrosting and triggering low-pressure protection. This reduces the risk of damage to the compressor 10, extends its service life, and results in a long overall lifespan and low operating costs for the air conditioner.

[0078] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom still fall within the scope of protection of this invention.

Claims

1. An air-side heat exchanger, characterized in that, include: The upper section includes multiple first branches arranged in parallel; The lower section is located below the upper section in the direction of gravity, and the lower section includes a plurality of second branch pipes arranged in parallel. A gas collecting pipe is connected to multiple first branch pipes and multiple second branch pipes, and the output end of the gas collecting pipe is directly connected to the lower partition. An on / off valve, located on the gas collection pipe, is used to control the connection or isolation between the upper and lower partitions.

2. The air-side heat exchanger according to claim 1, characterized in that, The air-side heat exchanger has a first operating mode and a second operating mode, and can switch between the first operating mode and the second operating mode; In the first operating mode, the on / off valve is open to allow refrigerant to be input through the gas collection pipe, and then enter the upper and lower partitions through the gas collection pipe; in the second operating mode, the on / off valve is closed to isolate the upper and lower partitions from each other, and the refrigerant is input only from the output end of the gas collection pipe, and then passes through the lower partition.

3. The air-side heat exchanger according to claim 1, characterized in that, It also includes a distributor, which is connected to the upper partition by a plurality of first branches, and the first branches are connected one-to-one with the first branch pipes; The distributor is connected to the lower partition by multiple second branches, and each second branch is connected to a corresponding second branch pipe.

4. The air-side heat exchanger according to claim 1, characterized in that, It also includes a control module, a first temperature sensor, and a second temperature sensor. The first temperature sensor is located on the first branch pipe and is used to acquire the surface temperature T1 of the upper partition. The second temperature sensor is located on the second branch pipe and is used to acquire the surface temperature T2 of the lower partition. The control module is used to control the on-off valve to close when the surface temperature T1 of the upper partition is continuously detected by Δtsmin ≥ the preset defrosting end temperature Ts, and to control the on-off valve to open when the surface temperature T2 of the lower partition is continuously detected by Δtsmin ≥ the preset defrosting end temperature Ts. Here, Δtsmin represents the minimum detection time.

5. The air-side heat exchanger according to claim 4, characterized in that, The on / off valve is an electric ball valve.

6. A refrigerant circulation system, characterized in that, Includes the air-side heat exchanger as described in any one of claims 1 to 5.

7. The refrigerant circulation system according to claim 6, characterized in that, It includes a refrigerant circulation loop, which is equipped with a compressor, a user-side heat exchanger, a throttling mechanism, an air-side heat exchanger, a four-way valve, and an outdoor fan. The four-way valve is located between the compressor and the user-side heat exchanger, and the air-side heat exchanger is located inside the outdoor fan.

8. The refrigerant circulation system according to claim 7, characterized in that, It also includes a gas-liquid separator, which is located between the compressor and the air-side heat exchanger.

9. A defrosting control method, used in the refrigerant circulation system according to any one of claims 7-8, characterized in that, include: During the heating cycle, the electric ball valve is kept in the open position. When Δtkmin continuously detects that both T1 and T2 are less than the preset defrosting start temperature Tk, the throttling mechanism is adjusted to the preset defrosting position, the four-way valve is switched to the defrosting state, and the outdoor fan is controlled to stop running and enter the defrosting operation state. When Δtsmin continuously detects that T1 ≥ preset defrosting end temperature Ts, the electric ball valve is controlled to close. When Δtsmin continuously detects that T2 ≥ preset defrosting end temperature Ts, the electric ball valve is opened, the four-way valve is switched to heating operation mode, the outdoor fan is started, the throttling mechanism is adjusted to the heating operation position, and defrosting is completed.

10. An air conditioner, characterized in that, Includes the refrigerant circulation system as described in any one of claims 6 to 8.

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