Air conditioning system and control method

Abstract

The present invention provides an air conditioning system and control method. The heat exchange piping of the first heat exchanger is divided into a first heat exchange tube group located near the heat exchange blower and a second heat exchange tube group located farther from the heat exchange blower. The first heat exchange tube group is connected on one side to the first throttle valve and on the other side to the C end of the four-way valve. The second heat exchange tube group is connected on one side to the first heat exchange tube group and on the other side to the E end of the four-way valve via a switchable bypass pipe. During heating operation, the bypass pipe can be connected, allowing some of the high-temperature, high-pressure refrigerant gas discharged from the compressor to pass through the bypass pipe and enter the second heat exchange tube group (i.e., the fin area prone to ice formation). The heat from the high-temperature gas quickly melts the ice, achieving a defrost function. This extends the operating time of the heating mode, ensures clean fin defrosting, and reduces dilution of the refrigeration oil by the liquid refrigerant, thereby increasing the service life of the compressor.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to an air conditioning system and a control method. Background Art

[0002] In the after-sales application link, the unit equipment has problems with incomplete defrosting and ice accumulation at the bottom of the fins. Such problems have a significant negative impact on product reliability and brand reputation. Through factory simulation test analysis, it was found that during the switching process from heating mode to defrost mode, there was a phenomenon of heat exchange efficiency degradation in the flow path area at the end of the fin: specifically, the frost layer in the upper area of the fin melted before the bottom area. When the defrost water flowed downward to the bottom of the fin under the action of gravity, the temperature of the bottom flow path had not yet reached the threshold required for the phase change of the ice layer, resulting in secondary condensation of liquid water on the low-temperature surface. Because the defrost process has a preset time limit, when the temperature of the bottom area of the fin rises to the threshold required for defrost, more than 50% of the defrost cycle time has been consumed, and the remaining time is insufficient to complete the complete phase change process of ice accumulation at the bottom. After verification of the cumulative effect of multiple cycles, the residual ice layer that has not been completely melted forms an ice blockage structure at the bottom of the fin, which may eventually cause stress concentration and frost heave cracking risks in the copper tube. Summary of the Invention

[0003] In order to solve the technical problem of low defrosting efficiency at the bottom of a heat exchanger in the prior art, the present invention provides an air conditioning system and a control method.

[0004] The technical solution adopted in the present invention is:

[0005] The present invention provides an air conditioning system, comprising a compressor, a first heat exchanger, a second heat exchanger, a first throttle valve, and a four-way valve, wherein the exhaust end and the intake end of the compressor are connected to the D end and the S end of the four-way valve respectively through pipes, and the C end of the four-way valve is connected to the first heat exchanger, the first throttle valve, the second heat exchanger, and the E end of the four-way valve in sequence through pipes;

[0006] The heat exchange pipes of the first heat exchanger are divided into a first heat exchange pipe group close to the heat exchange blower and a second heat exchange pipe group far away from the heat exchange blower. One side of the first heat exchange pipe group is connected to the first throttle valve and the other side is connected to the C end of the four-way valve. One side of the second heat exchange pipe group is connected to one side of the first heat exchange pipe group, and the other side is connected to the E end of the four-way valve through a switchable bypass pipe.

[0007] Furthermore, a second throttle valve is provided on the side of the second heat exchange tube group connected to the first heat exchange tube group.

[0008] Furthermore, the heat exchange fan is arranged at the top of the first heat exchanger, and the second heat exchange tube group is at least one layer of heat exchange pipes at the bottom of the first heat exchanger.

[0009] Furthermore, the heat exchange pipes of the second heat exchange tube group are arranged alternately with the heat exchange pipes at the bottom of the first heat exchange tube group.

[0010] The present invention also provides a method for controlling an air conditioning system, using the above-mentioned air conditioning system; the method comprises the following steps:

[0011] When the air conditioner operates in heating mode, determining whether the temperature difference ΔTc between the first heat exchanger and the ambient temperature is greater than a first set value A;

[0012] If so, the bypass pipe is connected to connect the pipes of the second heat exchange pipe group; if not, the bypass pipe is closed or remains closed.

[0013] Furthermore, the method further includes the following steps: after the bypass pipe is connected, when the temperature difference ΔTc between the first heat exchanger and the ambient temperature is less than or equal to the first set value A, the bypass pipe is closed.

[0014] When the air conditioner operates in cooling mode, determining whether the temperature difference ΔTe between the first heat exchanger and the ambient temperature is less than a second set value B;

[0015] If so, the bypass pipe is connected to connect the pipes of the second heat exchange pipe group; if not, the bypass pipe is closed or remains closed.

[0016] Furthermore, the method further includes the following steps: after the bypass pipe is connected, when the temperature difference ΔTe between the first heat exchanger and the ambient temperature is greater than or equal to the second set value B, the bypass pipe is closed.

[0017] Furthermore, after the bypass pipe is connected, the opening of the second throttle valve is controlled so that the temperature of the second heat exchange tube group after throttling is consistent with the temperature on one side of the first heat exchange tube group.

[0018] The present invention also provides a computer-readable storage medium for storing a computer program, which executes the above-mentioned control method when running.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] During heating operation, the bypass pipe can be connected, allowing some of the high-temperature, high-pressure refrigerant gas discharged from the compressor to pass through the bypass pipe and enter the second heat exchange tube group (the fin area prone to ice formation). The heat from the high-temperature gas quickly melts the ice layer, achieving a defrost function. This extends the operating time of the heating mode, ensures clean defrosting of the fins, and reduces the dilution of the refrigeration oil by the liquid refrigerant, thereby extending the life of the compressor. During cooling operation, the refrigerant is throttled by the first throttle valve to a low-temperature, low-pressure state. At this time, the bypass pipe is also connected, allowing some of the low-temperature refrigerant to directly enter the second heat exchange tube group, further reducing the fin temperature in this area and improving overall heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, 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.

[0022] Figure 1 is a system diagram of an embodiment of the present invention;

[0023] Figure 2 is a system diagram of a heating mode in an embodiment of the present invention;

[0024] Figure 3 is a system diagram of a cooling mode in an embodiment of the present invention;

[0025] Figure 4 is a front view of a first heat exchanger according to an embodiment of the present invention;

[0026] Figure 5 is a side view of a first heat exchanger according to an embodiment of the present invention;

[0027] Figure 6 is a top view of the first heat exchanger in an embodiment of the present invention;

[0028] Figure 7 is a flow chart in an embodiment of the present invention;

[0029] 1. Compressor;

[0030] 2. The first heat exchanger;

[0031] 3. Heat exchange fan;

[0032] 4. Second heat exchanger;

[0033] 5. Four-way valve;

[0034] 6. Gas-liquid separator;

[0035] 71. First throttle valve; 72. Second throttle valve;

[0036] 8. Bypass pipe; 81. Solenoid valve;

[0037] 9. Filter. DETAILED DESCRIPTION

[0038] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0039] The principle and structure of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

[0040] In existing technology, when switching from heating mode to defrost mode, heat exchange efficiency decreases in the flow path area at the end of the fins. Specifically, the frost layer on the upper fins melts before the bottom. When the defrosted water flows downward under gravity to the bottom of the fins, the temperature in the flow path at the bottom has not yet reached the threshold required for the ice layer to transition to a new phase, causing secondary condensation of the liquid water on the cold surface. Because the defrost process has a preset time limit, by the time the temperature in the area at the bottom of the fins reaches the required defrost threshold, more than 50% of the defrost cycle time has been consumed, leaving insufficient time for the complete phase transition of the ice at the bottom.

[0041] In this regard, Figures 1 to 3 As shown, the present invention provides an air conditioning system, comprising a compressor 1, a first heat exchanger 2 (a finned heat exchanger), a second heat exchanger 4 (specifically, a water-side heat exchanger), a first throttle valve 71, and a four-way valve 5. The exhaust and intake ends of the compressor 1 are connected to the D and S ends of the four-way valve 5, respectively, via pipes. The C end of the four-way valve 5 is sequentially connected to the first heat exchanger 2, the first throttle valve 71, the second heat exchanger 4, and the E end of the four-way valve 5 via pipes.

[0042] The heat exchange pipes of the first heat exchanger 2 are divided into a first heat exchange pipe group 21 located near the heat exchange blower 3 and a second heat exchange pipe group 22 located farther away from the heat exchange blower 3. One side of the first heat exchange pipe group is connected to the first throttle valve 71, and the other side is connected to the C end of the four-way valve 5. The second heat exchange pipe group is connected to the pipeline between the first throttle valve 71 and the first heat exchange pipe group on one side, and directly connected to the E end of the four-way valve 5 via a bypass pipe 8 on the other side. A solenoid valve 81 is provided on the bypass pipe 8 for opening and closing the bypass pipe 8.

[0043] During heating operation, if the ambient temperature is low and ice forms on the fins, the bypass pipe can be connected, allowing some of the high-temperature, high-pressure refrigerant gas discharged from the compressor to pass through the bypass pipe and enter the second heat exchange tube group (the fin area prone to ice formation). The heat from the high-temperature gas quickly melts the ice, achieving a defrost function and extending the operating time of the heating mode. During cooling operation, the refrigerant becomes low-temperature and low-pressure after being throttled by the first throttle valve. At this time, the bypass pipe is also connected, allowing some of the low-temperature refrigerant to enter the second heat exchange tube group directly, further reducing the fin temperature in this area and improving overall heat exchange efficiency.

[0044] By dividing the first heat exchanger's heat exchange tubes into two groups, one closer to the heat exchange fan and one farther away, and providing a bypass pipe between the second heat exchange tube group and the E end of the four-way valve, the system can dynamically adjust the refrigerant flow path in different operating modes. During heating, high-temperature refrigerant bypass is used to achieve defrost; during cooling, low-temperature refrigerant bypass is used to enhance heat exchange and reduce energy loss.

[0045] In a specific embodiment, Figure 3 、 4 As shown, the air conditioning system is equipped with a second throttle valve 72 in the connection line between the second heat exchange tube group 22 and the first heat exchange tube group 21. This valve independently adjusts the flow rate and pressure of the refrigerant in the second heat exchange tube group so that the temperature of the throttled refrigerant is balanced with the temperature of the refrigerant on the corresponding side of the first heat exchange tube group.

[0046] In heating mode, when the bypass pipe is opened, the high-temperature refrigerant flows through the second heat exchange tube group, and the second throttle valve can adjust the throttling area to ensure that its temperature drop rate matches that of the refrigerant in the first heat exchange tube group; in cooling mode, when the low-temperature refrigerant is diverted to the second heat exchange tube group, the second throttle valve adjusts the throttling area to avoid overcooling caused by excessive accumulation of cold energy, so that the two refrigerants reach temperature equilibrium before merging.

[0047] This design eliminates the low refrigerant mixing efficiency and high flow resistance caused by temperature differences in traditional systems by forcing the two refrigerant lines to balance their temperatures. Once refrigerants are combined, they flow more stably into subsequent pipelines, minimizing heat transfer attenuation caused by phase differences and reducing energy losses in the refrigerant circulation system.

[0048] Specifically, the outdoor unit's heat exchange fan is located at the top of the first heat exchanger, with its air outlet facing upward, forming a bottom-up air circulation path. At least one layer of heat exchange pipes in the bottom region of the first heat exchanger constitutes the second heat exchange tube group. Part of the heat exchange pipes at the bottom of the first heat exchange tube group may or may not overlap with the heat exchange pipes of the second heat exchange tube group.

[0049] In a preferred embodiment, Figures 4 to 6 As shown, part of the heat exchange pipes at the bottom of the first heat exchange tube group 21 and the heat exchange pipes of the second heat exchange tube group 22 are highly overlapped and staggered, thereby improving the heat exchange efficiency at the bottom of the heat exchanger.

[0050] The top-mounted heat exchanger fan positions the airflow upward from the bottom of the heat exchanger, preferentially passing through the second heat exchange area (i.e., the bottom-level pipes, which are prone to frost and condensation). In heating mode, when the high-temperature refrigerant enters the second heat exchange tube group through the bypass pipe, it heats and defrosts the fins of the bottom-level pipes, which are prone to frost, improving defrosting efficiency and extending heating time. In cooling mode, after the low-temperature refrigerant releases its cooling capacity in the second heat exchange area, the rising airflow is cooled by the refrigerant before reaching the first heat exchange tube group, enhancing the actual heat exchange efficiency of the first heat exchanger.

[0051] In a specific embodiment, filters 9 are provided on the connecting pipes between the first heat exchanger 2 and the second heat exchanger 4. Specifically, a filter 9 can be provided between the first throttle valve 71 and the first heat exchanger 2, a filter 9 can be provided between the first throttle valve 71 and the second heat exchanger 4, and a filter 9 can be provided between the second heat exchanger 4 and the E end of the four-way valve 5. The filters can intercept foreign particles and wear debris in the refrigerant, ensuring that the refrigerant remains clean during the pipeline circulation process.

[0052] The filter preferably features a replaceable filter element and is installed on the main refrigerant pipeline from the first heat exchanger to the second heat exchanger to reduce any additional impact on refrigerant flow resistance. During system operation, the filter continuously intercepts impurities such as metal debris and oxides, preventing them from entering the heat exchange tube assembly and potentially clogging microchannels or damaging valve seals.

[0053] In addition, it should be noted that the two sides of the first heat exchange tube group converge to form two main pipes, namely the main liquid pipe and the main gas pipe. During cooling, the refrigerant flows from the main gas pipe to the main liquid pipe; during heating, due to the switching direction of the four-way valve, the direction of the flow path becomes the main liquid pipe → the main gas pipe, and specifically the first heat exchange tube group is provided with a main liquid pipe inlet.

[0054] The second heat exchange tube group has the same convergence form as the first heat exchange tube group, specifically a liquid branch tube and a bronchial tube.

[0055] In a specific embodiment, a gas-liquid separator is further provided on the suction side of the compressor to reduce energy loss and pressure fluctuation.

[0056] like Figure 7 As shown, the present invention also proposes a control method for an air conditioning system; specifically comprising:

[0057] During heating operation, the temperature difference △Tc between the first heat exchanger (specifically, the temperature of the main liquid pipe, the fin temperature, or the conventional defrost detection position, etc.) and the environment is monitored in real time and compared with the preset threshold A, which is used as the basis for determining whether to open or close the bypass pipe.

[0058] The specific implementation process is as follows: The system continuously collects real-time data from the first heat exchanger's temperature and the ambient temperature, and calculates the temperature difference, ΔTc, between the two. When this temperature difference exceeds a preset value, A, it indicates that the first heat exchanger may be at risk of frost formation or localized overcooling due to low ambient temperature or excessive load. At this point, the control system immediately activates a bypass pipe, diverting the high-temperature refrigerant to the second heat exchange tube group. The high-temperature refrigerant releases heat in the second heat exchange area, directly raising the fin surface temperature there, melting existing frost or inhibiting new frost formation.

[0059] If ΔTc is detected to be below threshold A, the bypass remains closed, and the refrigerant flows along the main circulation path to maintain basic heating efficiency. This segmented control strategy precisely matches the needs of different operating conditions: in low-temperature, high-load scenarios, opening the bypass redistributes heat to prevent frost on the heat exchanger surface and the resulting decrease in heat transfer efficiency; in mild environments, unnecessary refrigerant diversion is avoided, reducing energy loss.

[0060] This method achieves preventative management of heat exchanger frost by directly linking temperature differential monitoring with bypass control. The second heat exchanger tube group continuously receives heat from the high-temperature refrigerant, allowing for defrosting. Simultaneously, the on-demand opening and closing of the bypass pipe dynamically balances refrigerant distribution between the main heat exchange area and the second heat exchanger tube group, ensuring an optimal combination of overall heating capacity and energy efficiency. Compared to traditional timed defrosting methods, this method reduces ineffective heating energy consumption and avoids room temperature fluctuations caused by excessive defrosting, improving system operational stability and user comfort.

[0061] In a further embodiment, during heating, when it is monitored that the temperature difference ΔTc between the first heat exchanger and the ambient temperature is restored to be less than or equal to the set threshold A, the system will close the solenoid valve and the second throttle valve associated with the bypass pipe.

[0062] When the ambient temperature rises or the heating load decreases, causing ΔTc to return to the normal range, the control system determines that the risk of frost on the first heat exchanger has been eliminated, immediately shutting off the power to the solenoid valve and closing the second throttle valve. This terminates the refrigerant diversion to the second heat exchange tube group, refocusing the refrigerant flow on the main heat exchange area. This allows the air conditioning system to achieve a dynamic balance between heat distribution and energy consumption in heating mode, ensuring frost protection in extreme environments while avoiding resource waste, ultimately improving overall energy efficiency and equipment life.

[0063] In a specific embodiment, the control method of the air-conditioning system further includes the steps of:

[0064] During cooling operation, the bypass pipe is opened and closed and the heat dissipation capacity is dynamically adjusted by monitoring the temperature difference △Te between the first heat exchanger and the ambient temperature and setting the threshold B as the trigger condition.

[0065] The specific execution process is as follows: When it is detected that △Te is lower than the set value B, it indicates that the ambient temperature is high and the current heat exchange load of the fins is high. When the load of the fins is exceeded, the burden on the fan will be increased simultaneously, which will increase the electric power of the fan and the power consumption of the whole machine will increase sharply. At this time, the control system connects the bypass pipe to divert part of the low-temperature refrigerant to the second heat exchange tube group, reducing the temperature of the fins, thereby reducing the power consumption of the whole machine. If △Te is not lower than the threshold value B, the bypass pipe is closed and the refrigerant circulates along the main path to maintain efficient cooling. If △Te is not lower than the threshold value B, the bypass pipe is closed and the refrigerant runs along the main path to maintain an efficient refrigeration cycle.

[0066] This control achieves heat dissipation redundancy by diverting the low-temperature refrigerant: in high-temperature operating conditions, the second heat exchange area serves as a supplementary heat dissipation module, using the low-temperature refrigerant to preferentially exchange heat with the environment, reducing the load on the first heat exchanger. It can also prevent the compressor exhaust temperature from abnormally increasing due to overheating of the refrigerant.

[0067] In a further embodiment, when it is monitored that the temperature difference ΔTe between the first heat exchanger and the ambient temperature rises to be greater than or equal to a set threshold value B, the system will close the solenoid valve and the second throttle valve associated with the bypass pipe.

[0068] In practice, when the ambient temperature drops or the cooling load decreases, causing ΔTe to reach or exceed threshold B again, the control system determines that the heat dissipation capacity of the main heat exchange area has been restored, immediately shuts off the power to the solenoid valve, and closes the second throttle valve. This terminates the diversion of the low-temperature refrigerant to the second heat exchange tube group, allowing the refrigerant flow to be refocused on the main heat exchange area. In other words, when the ambient temperature returns to a reasonable range, the low-temperature refrigerant diversion operation is promptly stopped, reducing the additional pressure drop caused by the bypass path. At the same time, the refrigerant flow rate in the main heat exchange area is restored to its optimal state, maintaining an efficient condensation process.

[0069] In a specific embodiment, after the bypass pipe is opened, the opening of the second throttle valve is dynamically adjusted to synchronize the refrigerant temperature after throttling of the second heat exchange tube group with the temperature of the first heat exchange tube group connected to the first throttle valve.

[0070] During implementation, the system collects real-time temperatures from the outlet side of the second heat exchange tube group (i.e., the branch liquid pipe) and the main liquid pipe of the first heat exchange tube group (connected to the first throttle valve). Based on the temperature difference, ΔTevb, the system adjusts the opening of the second throttle valve. The control system increases the opening of the second throttle valve to increase refrigerant flow, and decreases the opening to limit refrigerant flow if the flow rate is too low, ultimately aligning the two temperatures. This closed-loop control mechanism ensures balanced heat exchange efficiency within the refrigerant's diversion paths, preventing localized overcooling or overheating due to temperature differences.

[0071] Through temperature consistency control, the system achieves coordinated heat dissipation in multiple heat exchange areas: eliminating the temperature difference between the refrigerant in the first heat exchange tube group and the second heat exchange tube group can reduce the uneven phase change of the refrigerant or local pressure fluctuations caused by the temperature difference, and reduce the risk of abnormal vibration of the compressor caused by overheating or overcooling of the refrigerant.

[0072] The present invention also provides a computer-readable storage medium for storing a computer program, which executes the above-mentioned control method when running.

[0073] It should be noted that the terms used above are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0074] Unless otherwise specifically stated, the relative arrangement of the parts and steps, the numerical expressions and the numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values should be interpreted as being merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0075] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0076] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0077] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An air conditioning system comprising a compressor, a first heat exchanger, a second heat exchanger, a first throttle valve, and a four-way valve, wherein the exhaust end and the intake end of the compressor are connected to the D end and the S end of the four-way valve respectively via pipes, and the C end of the four-way valve is connected to the first heat exchanger, the first throttle valve, the second heat exchanger, and the E end of the four-way valve in sequence via pipes; characterized in that: The heat exchange pipes of the first heat exchanger are divided into a first heat exchange pipe group close to the heat exchange blower and a second heat exchange pipe group far away from the heat exchange blower. One side of the first heat exchange pipe group is connected to the first throttle valve and the other side is connected to the C end of the four-way valve. One side of the second heat exchange pipe group is connected to one side of the first heat exchange pipe group, and the other side is connected to the E end of the four-way valve through a switchable bypass pipe. When the air conditioner operates in heating mode, determining whether the temperature difference ΔTc between the first heat exchanger and the ambient temperature is greater than a first set value A; If yes, the bypass pipe is connected to connect the pipes of the second heat exchange pipe group; if no, the bypass pipe is closed or remains closed; A second throttle valve is further provided on the side of the second heat exchange tube group connected to the first heat exchange tube group; when the bypass pipe is opened, the opening of the second throttle valve is controlled to make the temperature of the second heat exchange tube group after throttling consistent with the temperature on one side of the first heat exchange tube group.

2. The air conditioning system according to claim 1, wherein: The heat exchange fan is arranged on the top of the first heat exchanger, and the second heat exchange tube group is at least one layer of heat exchange pipes arranged at the bottom of the first heat exchanger.

3. The air conditioning system according to claim 2, wherein: The heat exchange pipes of the second heat exchange tube group are arranged alternately with the heat exchange pipes at the bottom of the first heat exchange tube group.

4. A method for controlling an air conditioning system, characterized in that: An air conditioning system according to any one of claims 1 to 3; comprising step: When the air conditioner operates in cooling mode, determining whether the temperature difference ΔTe between the first heat exchanger and the ambient temperature is less than a second set value B; If so, the bypass pipe is connected to connect the pipes of the second heat exchange pipe group; if not, the bypass pipe is closed or remains closed.

5. The control method of the air conditioning system according to claim 4, further comprising the step of: after the bypass pipe is connected in the heating mode, when the temperature difference ΔTc between the first heat exchanger and the ambient temperature is less than or equal to a first set value A, closing the bypass pipe.

6. The control method of the air conditioning system according to claim 4, further comprising the step of: after the bypass pipe is connected in cooling mode, when the temperature difference ΔTe between the first heat exchanger and the ambient temperature is greater than or equal to a second set value B, closing the bypass pipe.

7. A computer-readable storage medium for storing a computer program, wherein the computer program executes the control method according to any one of claims 4 to 6 when executed.

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