Air conditioning system and control method thereof

Abstract

The embodiment of the application provides an air conditioning system and a control method thereof, relates to the technical field of air conditioning, and is used for preventing abnormal noise during defrosting of the air conditioning system. The air conditioning system comprises: an outdoor unit and at least one indoor unit; the outdoor unit comprises: a compressor, a solenoid valve, a first expansion valve, a first heat exchanger and a second heat exchanger; the indoor unit comprises a third heat exchanger; the gas outlet end of the compressor is connected with the first end of the first expansion valve and the second heat exchanger; the second end of the first expansion valve is connected with the first end of the solenoid valve and the first heat exchanger; the second end of the solenoid valve is connected with the third heat exchanger and a gas-liquid separator; and a controller is configured to: acquire an operating parameter of the air conditioning system in the case that the air conditioning system operates in a heating water mode; determine whether the air conditioning system meets a defrosting condition according to the operating parameter; and control the solenoid valve to be closed and the first expansion valve to be opened in the case that the defrosting condition is met, so that the air conditioning system starts defrosting.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioning, in particular to an air conditioning system and a control method thereof. BACKGROUND

[0002] With the continuous development of air conditioning technology, users have put forward higher and higher requirements for the comprehensive performance of air conditioning systems.

[0003] When the air conditioning system is in heating operation, frost will inevitably appear on the outdoor heat exchanger, and the frost thickness will gradually increase over time, which will cause the air conditioning capacity to gradually decrease. Therefore, in order to maintain the heat exchange capacity of the system, defrosting needs to be performed. At present, when the air conditioning system is defrosting, abnormal noise will occur, thereby causing the user experience to deteriorate. SUMMARY

[0004] The embodiments of the present application provide an air conditioning system and a control method thereof, which are used to prevent abnormal noise during defrosting of the air conditioning system.

[0005] In order to achieve the above-mentioned purpose, the technical scheme is adopted as follows.

[0006] In a first aspect, the embodiments of the present application provide an air conditioning system, which comprises: an outdoor unit and at least one indoor unit; the outdoor unit comprises: a compressor, a solenoid valve, a first expansion valve, a first heat exchanger and a second heat exchanger; the indoor unit comprises a third heat exchanger; the gas outlet end of the compressor is connected to the first end of the first expansion valve and the second heat exchanger; the second end of the first expansion valve is connected to the first end of the solenoid valve and the first heat exchanger; the second end of the solenoid valve is connected to the third heat exchanger and a gas-liquid separator; a controller is configured to: acquire an operating parameter of the air conditioning system in the case that the air conditioning system is in a heating water mode; determine whether the air conditioning system meets a defrosting condition according to the operating parameter; and control the solenoid valve to be closed and the first expansion valve to be opened in the case that the air conditioning system meets the defrosting condition, so as to make the air conditioning system start defrosting.

[0007] The technical scheme provided by the embodiments of the present application at least brings the following beneficial effects: the embodiments of the present application provide an air conditioning system, in the case that the air conditioning system is in a heating water mode, according to the operating parameter of the air conditioning system, whether the air conditioning system meets a defrosting condition is determined, and in the case that the air conditioning system meets the defrosting condition, the solenoid valve is controlled to be closed and the first expansion valve is controlled to be opened. It can be understood that the four-way valve inside the outdoor unit of the air conditioning system is cancelled, and the solenoid valve and the first expansion valve are added to replace the four-way valve to control the flow direction of the refrigerant in the system pipeline. Therefore, in the case that the defrosting condition is met, only the solenoid valve and the first expansion valve need to be controlled. In this way, not only can the abnormal noise caused by the reversing of the four-way valve during defrosting be prevented, but also the cost can be reduced.

[0008] In some embodiments, the controller is further configured to: in a case that the air conditioning system operates in the hot water production mode, control the electromagnetic valve to open and the first expansion valve to close.

[0009] In some embodiments, the controller is further configured to: in a case that the air conditioning system operates in the cooling mode, control the first expansion valve to open and the electromagnetic valve to close.

[0010] In some embodiments, the outdoor unit further comprises a second expansion valve, a first end of the second expansion valve being connected to the second heat exchanger, and a second end of the second expansion valve being connected to the third heat exchanger; the controller is further configured to: in a case that the air conditioning system operates in the cooling mode and the hot water production mode, acquire a load of the indoor unit; in a case that the load of the indoor unit is equal to a preset load, control the electromagnetic valve to close and the second expansion valve to open, and adjust an opening degree of the first expansion valve to a first preset opening degree; or, in a case that the load of the indoor unit is greater than the preset load, control the electromagnetic valve to close, and adjust the opening degree of the first expansion valve to a second preset opening degree, an opening degree of the second expansion valve to a third preset opening degree, and a rotating speed of the outdoor fan to a preset rotating speed; or, in a case that the load of the indoor unit is less than the preset load, control the first expansion valve to close and the electromagnetic valve to open, and adjust an opening degree of the second expansion valve to a fourth preset opening degree.

[0011] In some embodiments, the air conditioning system further comprises: a circulating water pump, the circulating water pump being connected to the second heat exchanger to form a water system, and being configured to provide power for circulation of water in the water system; a temperature sensor, the temperature sensor being arranged on the first heat exchanger, and being configured to detect an ambient temperature; a high-pressure pressure sensor, the high-pressure pressure sensor being arranged on an exhaust pipeline of the compressor, and being configured to detect a high-pressure pressure of the air conditioning system; the controller is further configured to: acquire the ambient temperature by the temperature sensor, and acquire the high-pressure pressure of the air conditioning system by the high-pressure pressure sensor; in a case that the ambient temperature is greater than or equal to a preset temperature, and the high-pressure pressure is greater than or equal to a preset threshold value, control the second expansion valve to throttle and the circulating water pump to open; or, in a case that the ambient temperature is greater than or equal to the preset temperature, and the high-pressure pressure is less than the preset threshold value, control the second expansion valve and the circulating water pump to close.

[0012] In some embodiments, the controller is further configured to: in a case that the ambient temperature is less than the preset temperature, control the second expansion valve and the circulating water pump to close.

[0013] In a second aspect, the embodiments of the present application provide a control method of an air conditioning system, the method being applied to the air conditioning system, and the method comprising: in a case that the air conditioning system operates in a hot water production mode, acquiring an operating parameter of the air conditioning system; determining whether the air conditioning system satisfies a defrosting condition according to the operating parameter; in a case that the defrosting condition is satisfied, controlling an electromagnetic valve to close and a first expansion valve to open, so that the air conditioning system starts defrosting.

[0014] In a third aspect, an embodiment of the present application provides a controller, comprising: one or more processors; one or more memories; wherein the one or more memories are configured to store computer program codes, the computer program codes comprising computer instructions, when the one or more processors execute the computer instructions, the controller executes the control method of the air conditioning system according to any one of the second aspect.

[0015] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, the computer readable storage medium comprising computer instructions, when the computer instructions are executed on a computer, the computer executes the control method of the air conditioning system according to any one of the second aspect.

[0016] In a fifth aspect, an embodiment of the present application provides a computer program product, the computer program product being directly loadable into a memory and containing software code, when the computer program product is loaded and executed by a computer, the computer program product can implement the control method of the air conditioning system according to any one of the second aspect.

[0017] It should be noted that the computer instructions described above can be stored on the computer readable storage medium in whole or in part. The computer readable storage medium can be packaged together with the processor of the controller or packaged separately from the processor of the controller, and the present application does not limit the same.

[0018] The beneficial effects of the second aspect to the fifth aspect of the present application are described above, and the beneficial effects of the first aspect are not repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings are included to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification, and are used together with the embodiments of the present application to explain the technical solutions of the present application, and do not constitute a limitation on the technical solutions of the present application.

[0020] Figure 1 A schematic diagram of the composition of an air conditioning system provided by an embodiment of the present application is shown in the following figure:

[0021] Figure 2 A schematic diagram of the structure of an air conditioning system provided by an embodiment of the present application is shown in the following figure:

[0022] Figure 3 A schematic diagram of the structure of another air conditioning system provided by an embodiment of the present application is shown in the following figure:

[0023] Figure 4 A hardware configuration block diagram of an air conditioning system provided by an embodiment of the present application is shown in the following figure:

[0024] Figure 5 A schematic diagram of the structure of another air conditioning system provided by an embodiment of the present application is shown in the following figure:

[0025] Figure 6 A circulation principle schematic diagram of an air conditioning system is provided for the embodiment of the present application;

[0026] Figure 7 Another circulation principle schematic diagram of an air conditioning system is provided for the embodiment of the present application;

[0027] Figure 8 A flow chart of a control method of an air conditioning system is provided for the embodiment of the present application;

[0028] Figure 9 Another circulation principle schematic diagram of an air conditioning system is provided for the embodiment of the present application;

[0029] Figure 10 Another circulation principle schematic diagram of an air conditioning system is provided for the embodiment of the present application;

[0030] Figure 11 A component state schematic diagram of an air conditioning system is provided for the embodiment of the present application;

[0031] Figure 12 Another component state schematic diagram of an air conditioning system is provided for the embodiment of the present application;

[0032] Figure 13 A flow chart of a control method of an air conditioning system is provided for the embodiment of the present application;

[0033] Figure 14 A flow chart of a control method of an air conditioning system is provided for the embodiment of the present application;

[0034] Figure 15 A flow chart of a control method of an air conditioning system is provided for the embodiment of the present application;

[0035] Figure 16 Another circulation principle schematic diagram of an air conditioning system is provided for the embodiment of the present application;

[0036] Figure 17 Another circulation principle schematic diagram of an air conditioning system is provided for the embodiment of the present application;

[0037] Figure 18 Another circulation principle schematic diagram of an air conditioning system is provided for the embodiment of the present application. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be described clearly and completely below with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0039] It should be noted that all directional indications, such as upper, lower, left, right, front, back, and the like, are used to describe the relative positions between the components shown in the figures and the motion conditions thereof, and if the specific posture changes, the directional indications will also change accordingly.

[0040] The terms "first", "second", "third", "fourth", "fifth", "sixth", "seventh" and "eighth" are used only to describe purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second", "third", "fourth", "fifth", "sixth", "seventh" and "eighth" can include one or more of the features explicitly or implicitly. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0041] In the description of the present application, it should be noted that unless otherwise specified and limited, the terms "connected", "connected" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. In addition, when describing the pipeline, "connected" and "connected" in the present application have the meaning of conducting. The specific meaning needs to be understood in combination with the context.

[0042] In the embodiments of the present application, the words such as "exemplary" or "for example" are used to represent as an example, illustration or description. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the words such as "exemplary" or "for example" are intended to present the relevant concept in a specific manner.

[0043] The defrosting process of the air conditioning system in the heating process is very important. Especially in winter, in the environment of low outdoor temperature and high humidity, the coil of the outdoor heat exchanger is easy to frost. If the frost is thick, it is easy to block the heat exchange channel of the outdoor heat exchanger and the air, and seriously reduce the heat exchange effect of the outdoor heat exchanger. The current defrosting process is generally realized by using four-way valve reversing to realize defrosting. The four-way valve reversing makes the refrigerant flow reversely, thereby realizing rapid defrosting. When the four-way valve reverses, the pressure and flow direction of the refrigerant in the air conditioning system change instantaneously, which is easy to cause the air conditioning system to produce a kind of impact sound similar to "ding". This noise is sometimes even very large, thus it is easy to cause the problem of poor user experience.

[0044] Based on this, the embodiment of the present application provides a control method of an air conditioning system. In the case that the air conditioning system operates in a hot water mode, whether the air conditioning system meets defrosting conditions is determined according to operating parameters of the air conditioning system, and in the case that the air conditioning system meets the defrosting conditions, the electromagnetic valve is controlled to be closed and the first expansion valve is controlled to be opened. In this way, abnormal noise caused by reversing of the four-way valve during defrosting can be prevented.

[0045] Figure 1 A schematic diagram of an air conditioning system according to an exemplary embodiment is provided in the present application. As shown in the figure, Figure 1 the air conditioning system 100 includes an outdoor unit 10, at least one indoor unit 20, and a water terminal 30.

[0046] The outdoor unit 10 is usually arranged outdoors, and the interior thereof can be provided with a compressor, a first heat exchanger, a second heat exchanger, a gas-liquid separator, and the like. The outdoor unit 10 is connected with the indoor unit 20 through a refrigerant circulation pipeline, and the outdoor unit 10 is connected with the water terminal 30 through a water supply pipeline.

[0047] The indoor unit 20 is usually arranged indoors, and the interior thereof can be provided with a third heat exchanger and the like.

[0048] The water terminal 30 guides warm water or hot water to a water-using area, such as a floor radiant heating device, through the water supply pipeline, and can also guide the warm water or hot water to a water tank for storage or re-heating, such as a water heater and the like.

[0049] In some embodiments, the indoor unit 20 is arranged in one-to-one correspondence with the floor radiant heating device. For example, one indoor unit 20 and one floor radiant heating device are arranged in each room.

[0050] Figure 2 A structural schematic diagram of an air conditioning system according to an exemplary embodiment is provided in the present application. As shown in the figure, Figure 2 the air conditioning system 100 further includes a compressor 111, a gas-liquid separator 112, a first heat exchanger 113, a second heat exchanger 114, a first expansion valve 115, an electromagnetic valve 116, a second expansion valve 117, a liquid-side stop valve 118, a gas-side stop valve 119, a circulating water pump 120 (not shown in the figure), an indoor expansion valve 121, a third heat exchanger 122, a floor radiant heating device 123, and a controller 124 (not shown in the figure). Figure 2 Figure 2

[0051] ​​In some embodiments, the compressor 111 is arranged between the first expansion valve 115 and the gas-liquid separator 112, compresses the refrigerant delivered by the gas-liquid separator 112, and delivers the compressed refrigerant to the circulation system through the first expansion valve 115 to provide power for the circulation of the refrigerant. The compressor 111 can be an inverter compressor with variable capacity based on inverter speed control.

[0052] In some embodiments, one end of the gas-liquid separator 112 is connected to the compressor 111, and the other end is connected to the first heat exchanger 113 through the electromagnetic valve 116. In the gas-liquid separator 112, the refrigerant flowing from the first heat exchanger 113 to the compressor 111 through the electromagnetic valve 116 is separated into gaseous refrigerant and liquid refrigerant. And the suction port of the compressor 111 is mainly supplied with gaseous refrigerant from the gas-liquid separator 112.

[0053] In some embodiments, the first heat exchanger 113 can also be referred to as an outdoor heat exchanger. One end of the first heat exchanger 113 is connected to the compressor 111 through the first expansion valve 115, and the other end is connected to the second heat exchanger 114. The first heat exchanger 113 has a first inlet and outlet for the circulation of refrigerant between the first heat exchanger 113 and the suction port of the compressor 111 through the gas-liquid separator 112, and has a second inlet and outlet for the circulation of refrigerant between the first heat exchanger 113 and the third heat exchanger 122. The first heat exchanger 113 exchanges heat between the refrigerant flowing in the heat transfer pipe connected between the first inlet and outlet and the outdoor air, and works as a condenser in the cold cycle.

[0054] In some embodiments, the second heat exchanger 114 can also be referred to as a water-fluorine heat exchanger. The refrigerant side of the second heat exchanger is connected to the compressor 111 and the third heat exchanger 122, and the other side of the second heat exchanger 114 is provided with a water inlet and a water outlet, and is connected to the circulating water pump 120 to form a circulation loop of the water system. The second heat exchanger 114 is used for exchanging heat between the refrigerant and the water in the water system to achieve the purpose of heating using the water system.

[0055] In some embodiments, the first end of the first expansion valve 115 is connected to the gas outlet of the compressor 111, and the second end of the first expansion valve 115 is connected to the first end of the electromagnetic valve. The first expansion valve 115 is used to control the flow direction of the refrigerant in the system pipeline.

[0056] In some embodiments, the first end of the electromagnetic valve 116 is connected to the first expansion valve 115, and the second end of the electromagnetic valve 116 is connected to the third heat exchanger and the gas-liquid separator. The electromagnetic valve 116 is used to control the flow direction of the refrigerant in the system pipeline.

[0057] Optionally, the electromagnetic valve 116 can be replaced by an electronic expansion valve to control the flow of refrigerant in the system pipeline.

[0058] In some embodiments, the second expansion valve 117 has a function of expanding and reducing the pressure of the refrigerant flowing through the second expansion valve 117, and can be used to adjust the supply amount of the refrigerant in the system pipeline. If the opening degree of the second expansion valve 117 is reduced, the flow path resistance of the refrigerant passing through the second expansion valve 117 is increased. If the opening degree of the electronic expansion valve 121 is increased, the flow path resistance of the refrigerant passing through the second expansion valve 117 is reduced. In this way, even if the state of other devices in the circuit does not change, when the opening degree of the second expansion valve 117 changes, the refrigerant flow to the indoor unit 20 will also change.

[0059] In some embodiments, the liquid-side stop valve 118 and the gas-side stop valve 119 are used to control the opening and closing of the valve core to control the passage and stop of the refrigerant. The liquid-side stop valve 118 is arranged on the liquid pipe, and the gas-side stop valve 119 is arranged on the gas pipe. The liquid pipe and the gas pipe are part of the refrigerant circulation pipeline for connecting the indoor unit and the outdoor unit, the liquid pipe is used to transport two-phase refrigerant, and the gas pipe is used to transport gaseous refrigerant.

[0060] In addition, the liquid-side stop valve 118 and the gas-side stop valve 119 can be arranged in the outdoor unit 10 as part of the outdoor unit 10, or can be arranged outside the outdoor unit 10, and the embodiments of the present application do not limit the installation position of the liquid-side stop valve 118 and the gas-side stop valve 119.

[0061] In some embodiments, the circulating water pump 120 is connected with the second heat exchanger 114 to form a water system, and is used to provide power for the circulation of water in the water system. The circulating water pump can be installed in the indoor unit 20 as a built-in circulating water pump, or can be installed outside the indoor unit 10 as an external circulating water pump, and the embodiments of the present application do not limit the installation position of the circulating water pump.

[0062] In some embodiments, the indoor expansion valve 121 is arranged on the connecting pipeline between the first heat exchanger 113 and the third heat exchanger 122.

[0063] In some embodiments, the third heat exchanger 122 can also be referred to as an indoor heat exchanger. The third heat exchanger 122 has a third inlet and outlet for the liquid refrigerant to flow between the first heat exchanger 113, and has a fourth inlet and outlet for the gaseous refrigerant to flow between the discharge port of the compressor 111. The third heat exchanger 122 exchanges heat between the refrigerant flowing in the heat transfer pipe connected between the third inlet and outlet and the indoor air.

[0064] The floor radiant heating device 123 is connected with the outdoor unit 10 through a water supply pipeline, and the outdoor unit 10 transmits hot water to the floor radiant heating device 123 to heat the floor of the indoor room.

[0065] In the embodiments shown in the present application, the controller 124 refers to a device that can generate operation control signals according to instruction operation codes and timing signals to instruct the air conditioning system to execute control instructions. For example, the controller can be a central processing unit (CPU), a general processor network processor (NP), a digital signal processing (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The controller can also be other devices with processing functions, such as circuits, devices, or software modules, and the embodiments of the present application do not make any limitation thereto.

[0066] In addition, the controller 124 can be used to control the operation of each component in the air conditioning system 100, so that each component of the air conditioning system 100 operates to achieve each predetermined function of the air conditioning system.

[0067] In some embodiments, the controller 124 can be integrated in the outdoor unit 10, that is, the outdoor unit 10 can control the operation of each component in the air conditioning system 100.

[0068] In some other embodiments, the air conditioning system can further include a third expansion valve 125, as shown in Figure 3 The first end of the third expansion valve 125 is connected with the first heat exchanger 113, and the second end is connected with the second expansion valve in parallel to the third heat exchanger 122. The third expansion valve 125 has the function of expanding and reducing the pressure of the refrigerant flowing through it, and can be used to adjust the supply amount of refrigerant in the system pipeline.

[0069] It should be noted that the first expansion valve 115, the second expansion valve 117, the third expansion valve 125, and the indoor expansion valve 121 all have three working states:

[0070] (1) Throttling state: In the throttling state, it plays a role of throttling and reducing the pressure of the refrigerant flowing in the air conditioning circulation system pipeline. When high-pressure refrigerant flows through any one of the first expansion valve 115, the second expansion valve 117, the third expansion valve 125, and the indoor expansion valve 121 in the throttling state, it becomes low-pressure refrigerant.

[0071] (2) Open state, which can be fully open or open to a preset opening degree, which is not limited.

[0072] (3) a closed state, in which the refrigerant flowing in the pipeline cannot pass through any of the first expansion valve 115, the second expansion valve 117, the third expansion valve 125, and the indoor expansion valve 121.

[0073] Figure 4 A hardware configuration block diagram of an air conditioning system according to an exemplary embodiment is provided for the present application. As shown in Figure 5 The air conditioning system 100 can further include a high-pressure pressure sensor 201, a first temperature sensor 202, a second temperature sensor 203, a third temperature sensor 204, an outdoor fan 205, an outdoor fan motor 206, a display 207, an indoor fan 208, and an indoor fan motor 209.

[0074] In some embodiments, as shown in Figure 5 The high-pressure pressure sensor 201 is disposed on the compressor 111 for detecting the high-pressure pressure of the air conditioning system 100.

[0075] In some embodiments, as shown in Figure 5 The first temperature sensor 202 is disposed on the first heat exchanger 113 for detecting the ambient temperature.

[0076] In some embodiments, as shown in Figure 5 The second temperature sensor 203 is disposed at the water outlet of the second heat exchanger 114 for detecting the water outlet temperature of the second heat exchanger 114.

[0077] In some embodiments, as shown in Figure 5 The third temperature sensor 204 is disposed at the water inlet of the second heat exchanger 114 for detecting the water inlet temperature of the second heat exchanger 114.

[0078] In some embodiments, the outdoor fan 205 generates an airflow of outdoor air through the first heat exchanger 113 to facilitate heat exchange between the refrigerant flowing in the heat transfer pipe between the first inlet and the second inlet and the outdoor air.

[0079] In some embodiments, the outdoor fan motor 206 is used to drive or change the rotation speed of the outdoor fan 205.

[0080] In some embodiments, the display 207 is used to display the indoor temperature or the operating mode of the air conditioning system. The operating mode of the air conditioning system includes a cooling mode and a hot water mode. The hot water mode can include a floor heating mode and a heat recovery mode.

[0081] In some embodiments, the indoor fan 208 generates an airflow of indoor air through the third heat exchanger 122 to facilitate heat exchange between the refrigerant flowing in the heat transfer pipe between the third inlet and the fourth inlet and the indoor air.

[0082] In some embodiments, the indoor fan motor 209 is used to drive or change the rotating speed of the indoor fan 208.

[0083] In some embodiments, the air conditioning system 100 is also attached with a remote controller, which has the function of communicating with the controller 124, for example, using infrared rays or other communication methods. The remote controller is used for the user to control various controls of the air conditioning system, realizing the interaction between the user and the air conditioning system 100.

[0084] Those skilled in the art can understand that, Figure 3 The hardware structure shown in the above figure does not constitute a limitation on the multi-split air conditioning system, and the multi-split air conditioning system can include more or fewer components than the figure, or combine certain components, or different component arrangements.

[0085] Figure 6 A schematic diagram of the circulation principle of an air conditioning system according to an exemplary embodiment is provided in the present application. As shown in the figure, Figure 5 When the air conditioning system is cooling alone, the first expansion valve 115 is in an open state, and the electromagnetic valve 116 is in a closed state. The high-temperature and high-pressure gaseous refrigerant discharged from the compressor 111 enters the first heat exchanger 113 through the first expansion valve 115, and becomes a medium-temperature and high-pressure liquid refrigerant after heat exchange with air in the first heat exchanger 113. The refrigerant flowing out of the first heat exchanger 113 becomes a low-temperature and low-pressure liquid refrigerant after throttling and pressure reduction by the throttling device. The refrigerant after throttling and pressure reduction exchanges heat with air in the third heat exchanger 122, and becomes a low-temperature and low-pressure gaseous refrigerant. The refrigerant flowing out of the third heat exchanger 122 enters the gas-liquid separator 112 through the indoor expansion valve 121 and the gas-side stop valve 119 in turn, and returns to the compressor 111 again.

[0086] Figure 7 A schematic diagram of the circulation principle of an air conditioning system according to an exemplary embodiment is provided in the present application. As shown in the figure, Figure 6 When the air conditioning system is cooling alone, the first expansion valve 115 is in an open state, and the electromagnetic valve 116 is in a closed state. The high-temperature and high-pressure gaseous refrigerant discharged from the compressor 111 enters the first heat exchanger 113 through the first expansion valve 115, and becomes a medium-temperature and high-pressure liquid refrigerant after heat exchange with air in the first heat exchanger 113. The refrigerant flowing out of the first heat exchanger 113 becomes a low-temperature and low-pressure liquid refrigerant after throttling and pressure reduction by the throttling device. The refrigerant after throttling and pressure reduction exchanges heat with air in the third heat exchanger 122, and becomes a low-temperature and low-pressure gaseous refrigerant. The refrigerant flowing out of the third heat exchanger 122 enters the gas-liquid separator 112 through the indoor expansion valve 121 and the gas-side stop valve 119 in turn, and returns to the compressor 111 again.

[0087] The embodiments provided in the present application will be specifically introduced below in conjunction with the drawings of the specification.

[0088] AsFigure 8 As shown, the embodiment of the present application provides a control method of an air conditioning system, which comprises:

[0089] S101, the controller acquires the operation parameters of the air conditioning system in the case that the air conditioning system runs the hot water heating mode.

[0090] In some embodiments, when the user needs to use the air conditioner for hot water heating, the user can issue a start-up instruction to the air conditioning system through a terminal device, or issue a start-up instruction to the air conditioning system through a remote controller of the air conditioning system. In response to the start-up instruction, the controller controls the components of the air conditioning system to start working. Further, the user issues a mode control instruction to the air conditioning system through the terminal device or the remote controller of the air conditioning system to instruct the air conditioning system to run a corresponding operation mode. For example, the user issues a hot water heating mode control instruction to the air conditioning system, and then the air conditioning system runs the hot water heating mode.

[0091] In other embodiments, in the case that the air conditioning system has already run the refrigeration mode, if the user needs to use the air conditioner for hot water heating, the user can issue a mode switching instruction to the air conditioning system through a terminal device or a remote controller of the air conditioning system to instruct the air conditioning system to switch to a corresponding operation mode, for example, an instruction to switch from the refrigeration mode to the hot water heating mode, and in response to the mode switching instruction, the air conditioning system switches to the hot water heating mode.

[0092] In some embodiments, in the case that the air conditioning system runs the hot water heating mode, the operation parameters of the air conditioning system are acquired. For example, the operation parameters can include the continuous heating running time length of the compressor, the continuous heating time length of the compressor, the outdoor environment temperature, the condensation temperature of the second heat exchanger, etc.

[0093] It should be noted that one or more of the operation parameters can be acquired to determine whether the air conditioning system meets the defrosting condition.

[0094] S102, the controller determines whether the air conditioning system meets the defrosting condition according to the operation parameters.

[0095] In some embodiments, whether the air conditioning system meets the defrosting condition is determined according to the operation parameters of the air conditioning system.

[0096] For example, in the case that the cumulative heating time length of the compressor is greater than or equal to a first preset heating time length, the continuous heating time length of the compressor is greater than or equal to a second preset heating time length, the outdoor environment temperature is greater than a preset environment temperature, the condensation temperature of the second heat exchanger is less than a first preset condensation temperature, and the condensation temperature of the second heat exchanger is less than a preset condensation temperature for a time reaching a first preset time length, it is determined that the air conditioning system meets the defrosting condition.

[0097] Or, in the case that the cumulative heating time of the compressor is greater than or equal to the first preset heating time, the continuous heating time of the compressor is greater than or equal to the second preset heating time, the temperature difference between the outdoor environment temperature and the condensing temperature of the second heat exchanger is greater than the preset threshold, and the temperature difference between the outdoor environment temperature and the condensing temperature of the second heat exchanger is greater than the preset threshold for a duration reaching the first preset duration, it is determined that the air conditioning system meets the defrosting condition.

[0098] Or, in the case that the cumulative heating time of the compressor is greater than or equal to the first preset heating time, the continuous heating time of the compressor is greater than or equal to the second preset heating time, the condensing temperature of the second heat exchanger is less than the second preset condensing temperature, and the condensing temperature of the second heat exchanger is less than the second preset condensing temperature for a duration reaching the second preset duration, it is determined that the air conditioning system meets the defrosting condition.

[0099] Optionally, the first preset heating time ranges from 10 minutes to 30 minutes, the second preset heating time is 5 minutes, the preset environment temperature ranges from 1 degree Celsius to 6 degrees Celsius, the first preset condensing temperature is -3 degrees Celsius, the second preset condensing temperature ranges from -13 degrees Celsius to -11 degrees Celsius, the first preset duration ranges from 3 minutes to 5 minutes, the preset threshold ranges from 5 degrees Celsius to 12 degrees Celsius, the first preset duration ranges from 3 minutes to 5 minutes, and the second preset duration ranges from 3 hours to 9 hours.

[0100] S103, in the case that the defrosting condition is met, the controller controls the electromagnetic valve to be closed and the first expansion valve to be opened, so that the air conditioning system starts defrosting.

[0101] In some embodiments, in the case that the defrosting condition is met, the electromagnetic valve is controlled to be closed and the first expansion valve is controlled to be opened, so that the air conditioning system starts defrosting.

[0102] In some embodiments, in order to prevent noise caused by pressure mutation of the air conditioning system, the first expansion valve is slowly opened.

[0103] In some embodiments, as shown in Figure 9 In the case that the defrosting condition is met, the indoor expansion valve is also throttled.

[0104] It can be understood that, based on the air conditioning system shown in Figure 6 Because the first heat exchanger is frosted, in order to eliminate the frost layer on the first heat exchanger, defrosting can be performed by using high-temperature refrigerant. Since the air conditioning system cancels the four-way valve, in the case that the defrosting condition is met, only the electromagnetic valve needs to be controlled to be closed and the first expansion valve needs to be controlled to be opened, so as to control the flow direction of the refrigerant in the system pipeline, that is, the air conditioning system can be controlled to start defrosting, thereby preventing abnormal noise caused by the four-way valve reversing during defrosting.

[0105] As shown in Figure 10 As shown in FIG. 1, when the defrosting condition is met, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor enters the first heat exchanger through the first expansion valve, is liquefied into low-temperature and high-pressure liquid refrigerant in the first heat exchanger, and realizes defrosting of the first heat exchanger. Then, the refrigerant flows out of the outdoor heat exchanger, flows to the third heat exchanger through the liquid-side stop valve, and becomes low-temperature and low-pressure gaseous refrigerant after heat exchange with air. The refrigerant flowing out of the third heat exchanger enters the gas-liquid separator through the indoor expansion valve and the gas-side stop valve in sequence, and returns to the compressor again.

[0106] As shown in Figure 11 As shown in FIG. 2, when the air conditioning system runs in the hot water mode, the electromagnetic valve is controlled to be opened, the first expansion valve is controlled to be closed, the second expansion valve is controlled to be opened, and the indoor expansion valve is controlled to be throttled.

[0107] As shown in Figure 12 As shown in FIG. 3, when the air conditioning system runs in the cooling mode, the first expansion valve is controlled to be opened, the electromagnetic valve is controlled to be closed, the second expansion valve is controlled to be opened, and the indoor expansion valve is controlled to be closed.

[0108] Based on the embodiment shown in Figure 8 The embodiment of the present application provides a control method of an air conditioning system. When the air conditioning system runs in the hot water mode, whether the air conditioning system meets the defrosting condition is determined according to the operating parameters of the air conditioning system. When the defrosting condition is met, the electromagnetic valve is controlled to be closed and the first expansion valve is controlled to be opened. It can be understood that the four-way valve inside the outdoor unit of the air conditioning system is cancelled, and the electromagnetic valve and the first expansion valve are added to replace the four-way valve to control the flow direction of the refrigerant in the system pipeline. Therefore, when the defrosting condition is met, only the electromagnetic valve and the first expansion valve need to be controlled. In this way, not only can the abnormal noise caused by the reversing of the four-way valve during defrosting be prevented, but also the cost can be reduced.

[0109] As shown in Figure 13 As shown in FIG. 4, when the defrosting condition is met, after the electromagnetic valve is controlled to be closed and the first expansion valve is controlled to be opened, the control method further includes the following steps:

[0110] S201, the controller acquires the environment temperature and the high-pressure of the air conditioning system.

[0111] In some embodiments, the environment temperature is acquired by a temperature sensor, and the high-pressure of the air conditioning system is acquired by a high-pressure sensor.

[0112] Optionally, when the air conditioning system is in the defrosting mode, the controller can periodically acquire the environment temperature and the high-pressure of the air conditioning system according to a preset period.

[0113] S202, the controller controls the second expansion valve to throttle and the circulating water pump to start, in a case that the ambient temperature is greater than or equal to a preset temperature and the high-pressure pressure is greater than or equal to a preset threshold.

[0114] Optionally, the preset temperature can be pre-set by the air conditioning system when it is manufactured, or can be obtained by the controller from other air conditioning systems, which is not limited. For example, the preset temperature is 3℃. The preset pressure can be pre-set by the air conditioning system when it is manufactured, or can be obtained by the controller from other air conditioning systems, which is not limited. For example, the preset pressure is 1.5MPa.

[0115] It should be noted that, in a case that the ambient temperature is greater than or equal to a preset temperature and the high-pressure pressure is greater than or equal to a preset pressure, it can be determined that the high-pressure pressure of the air conditioning system is moderate, and it can be determined that the defrosting speed can reach the expectation, therefore, only the second expansion valve needs to be controlled to throttle, that is, the second expansion valve throttles the refrigerant flowing in the circulating pipeline in the throttling state, so as to reasonably distribute the refrigerant flow. In addition, the circulating water pump can also be controlled to keep in the open state to continue heating water.

[0116] S203, the controller controls the second expansion valve and the circulating water pump to close, in a case that the ambient temperature is greater than or equal to a preset temperature and the high-pressure pressure is less than a preset threshold.

[0117] It should be noted that, in a case that the ambient temperature is greater than or equal to a preset temperature and the high-pressure pressure is less than a preset threshold, it can be determined that the high-pressure pressure of the air conditioning system is low, and it can be determined that the defrosting speed of the first heat exchanger is serious, at this time, the defrosting speed cannot reach the expectation. Therefore, in order to improve the defrosting speed, the second expansion valve is controlled to close, so that the high-temperature and high-pressure refrigerant flowing out of the compressor stays in the first heat exchanger for a longer time, and the high-temperature and high-pressure refrigerant has a longer time to melt the frost layer on the second heat exchanger, so that the defrosting speed is improved. In addition, the circulating water pump can also be controlled to close to stop heating water, so that the low-temperature and low-pressure refrigerant flowing out of the first heat exchanger will not enter the second heat exchanger, so that only the high-temperature and high-pressure refrigerant is in the first heat exchanger, which can improve the defrosting speed.

[0118] In one possible implementation, in a case that the ambient temperature is greater than or equal to a preset temperature and the high-pressure pressure is less than a preset threshold, the third expansion valve is periodically controlled to close according to a preset period.

[0119] In another possible implementation, in a case that the ambient temperature is greater than or equal to a preset temperature and the high-pressure pressure is less than a preset threshold, the third expansion valve is controlled to close to a preset opening degree, that is, the opening degree of the third expansion valve is adjusted to a preset opening degree.

[0120] It can be understood that the preset opening degree is small, and the purpose is also to increase the residence time of the high-temperature and high-pressure refrigerant flowing out of the compressor in the second heat exchanger, thereby improving the defrosting speed.

[0121] S204, the controller controls the second expansion valve and the circulating water pump to be closed in the case that the ambient temperature is less than the preset temperature.

[0122] It should be noted that in the case that the ambient temperature is less than the preset temperature, it can be determined that the first heat exchanger is seriously frosted, at this time, the defrosting speed cannot meet the expectation, therefore, in order to improve the defrosting speed, the second expansion valve and the circulating water pump are also controlled to be closed. Here, reference is made to the detailed description of controlling the second expansion valve and the circulating water pump to be closed in step S203.

[0123] The complete process of the control method of the air conditioning system will be introduced exemplarily in combination with a flow chart as shown in Figure 14

[0124] As shown in Figure 14 , the control process starts:

[0125] S1, the air conditioning system runs in a heating water mode.

[0126] It is judged whether the air conditioning system meets the defrosting condition.

[0127] If yes, the following step S2 and step S3 are executed.

[0128] If no, the following step S7 and step S8 are executed.

[0129] S2, the electromagnetic valve is controlled to be closed and the first expansion valve is controlled to be opened.

[0130] S3, the indoor expansion valve is throttled.

[0131] It is judged whether the ambient temperature is greater than or equal to the preset temperature.

[0132] If yes, the following step S4 is executed.

[0133] If no, the following step S6 is executed.

[0134] S4, it is judged whether the high-pressure pressure is greater than or equal to the preset pressure.

[0135] If yes, the following step S5 is executed.

[0136] If no, the following step S6 is executed.

[0137] S5, the second expansion valve is throttled and the circulating water pump is controlled to be kept opened.

[0138] S6, the second expansion valve is controlled to be closed and the circulating water pump is controlled to be closed. ​

[0139] S7, controlling the first expansion valve to close and the electromagnetic valve to open.

[0140] S8, controlling the second expansion valve to open and the indoor expansion valve to close.

[0141] In some embodiments, as shown in FIG. 1, the control method further comprises the following steps: Figure 15

[0142] S301, the controller acquires the indoor unit load when the air conditioning system is running in the cooling mode and the hot water mode.

[0143] The indoor unit load is a load generated by the inconsistency between the user set temperature and the current indoor environment temperature for the indoor unit. For example, in the cooling mode, the user sets the temperature to 20°C, and the actual indoor temperature is 26°C, thus a load is generated, which is the indoor unit load.

[0144] Optionally, the parameters affecting the indoor unit load include the indoor environment temperature, the outdoor environment temperature, the number of indoor units, the building area, the indoor humidity, the set temperature, etc.

[0145] S302, the controller controls the electromagnetic valve to close and the second expansion valve to open, and adjusts the opening degree of the first expansion valve to a first preset opening degree when the indoor unit load is equal to a preset load.

[0146] Optionally, the first preset opening degree is small, and the first preset opening degree can be preset by the air conditioning system when it is manufactured, or can be acquired by the controller from other air conditioning systems, which is not limited.

[0147] In some embodiments, when the indoor unit load is equal to the preset load, the outdoor fan is also controlled to close to reduce the flow speed of the refrigerant in the first heat exchanger.

[0148] It can be understood that when the indoor unit load is equal to the preset load, the electromagnetic valve is controlled to close, and the opening degree of the first expansion valve is adjusted to the first preset opening degree to prevent the refrigerant from staying in the first heat exchanger. As shown in FIG. 1, the first heat exchanger and the second heat exchanger are connected in parallel as a condenser, and the third heat exchanger is used as an evaporator. However, due to the closing of the outdoor fan and the small first preset opening degree, the heat exchange effect of the first heat exchanger is not obvious, so that most of the circulating refrigerant flows into the second heat exchanger, so that the amount of circulating refrigerant entering the second heat exchanger increases, thereby being able to produce enough hot water. Figure 16

[0149] S303, the controller controls the electromagnetic valve to close, adjusts the opening degree of the first expansion valve to a second preset opening degree, the opening degree of the second expansion valve to a third preset opening degree, and the rotating speed of the outdoor fan to a preset rotating speed when the indoor unit load is greater than the preset load. ​​

[0150] Optionally, the second preset opening, the third preset opening and the preset speed may be preset by the air-conditioning system when it leaves the factory, or may be obtained by the controller from other air-conditioning systems, which is not limited to this.

[0151] It is understandable that when the load of the indoor unit is greater than the preset load, it can be determined that the amount of refrigerant involved in the cycle is larger, and accordingly, the amount of refrigerant involved in the cycle in the first heat exchanger is larger. In order to maximize the amount of refrigerant used for heat recovery and hot water production in the second heat exchanger, after controlling the first expansion valve to open and the solenoid valve to close, such as Figure 17 As shown, the first heat exchanger and the second heat exchanger are connected in parallel as a condenser, and the third heat exchanger is used as an evaporator, so that the refrigerant discharged from the compressor is split into two paths and enters the second heat exchanger and the first heat exchanger respectively. Furthermore, by adjusting the opening of the second expansion valve and the speed of the outdoor fan, the refrigerant flow entering the first heat exchanger and the second heat exchanger is distributed to maximize the refrigerant flow in the second heat exchanger for heat recovery to produce hot water, thereby maximizing the production of hot water.

[0152] S304: When the load of the indoor unit is less than the preset load, the controller controls the first expansion valve to close and the solenoid valve to open, and adjusts the opening of the second expansion valve to a fourth preset opening.

[0153] Optionally, the fourth preset opening degree may be pre-set by the air-conditioning system when it leaves the factory, or may be obtained by the controller from other air-conditioning systems, which is not limited to this.

[0154] Optionally, the user turns on an indoor unit with a smaller internal capacity. When the ambient temperature is lower than a preset threshold, the load of the indoor unit is lower than the preset load.

[0155] It is understandable that when the indoor unit load is less than the preset load, the amount of refrigerant circulating in the third heat exchanger is small. If the first heat exchanger and the second heat exchanger are connected in parallel, the refrigerant is split into two paths and enters the first heat exchanger and the second heat exchanger respectively, and the first heat exchanger is almost entirely liquid refrigerant, and the liquid refrigerant flow rate is small, resulting in insufficient amount of refrigerant circulating in the second heat exchanger. Therefore, the amount of refrigerant used for heat recovery to produce hot water in the second heat exchanger is small, and the pressure is low, resulting in poor effect of using heat recovery to produce hot water, or even failure to produce hot water.

[0156] Therefore, after controlling the first expansion valve to close and the solenoid valve to open, Figure 18 As shown, the third heat exchanger and the first heat exchanger are connected in parallel as an evaporator, and the second heat exchanger serves as a condenser. The refrigerant flowing out of the third heat exchanger and the first heat exchanger will enter the second heat exchanger, so that the amount of refrigerant participating in the circulation entering the second heat exchanger increases, thereby being able to produce sufficient hot water.

[0157] Based on Figure 15 According to the air conditioning system provided by the embodiments of the present application, the water in the second heat exchanger is heated by the sensible heat of the refrigerant, so that the prepared hot water can reach a high temperature, and other energy (such as electric energy) is not needed to prepare the hot water. In addition, by controlling various valves, sufficient hot water can be prepared regardless of the load of the indoor unit.

[0158] In some embodiments, based on Figure 3 According to the air conditioning system shown in the embodiments of the present application, when the load of the indoor unit is equal to the preset load, the first expansion valve is controlled to be closed, the electromagnetic valve is controlled to be opened, the third expansion valve is controlled to be closed, and the opening degree of the second expansion valve is adjusted to the first opening degree.

[0159] Alternatively, when the load of the indoor unit is less than the preset load, the first expansion valve is controlled to be closed, the electromagnetic valve is controlled to be opened, and the opening degree of the second expansion valve is adjusted to the second opening degree and the opening degree of the third expansion valve is adjusted to the third opening degree.

[0160] Alternatively, when the load of the indoor unit is greater than the preset load, the first expansion valve is controlled to be opened, the electromagnetic valve is controlled to be closed, the opening degree of the second expansion valve is adjusted to the fourth opening degree, the opening degree of the third expansion valve is adjusted to the fifth opening degree, and the rotating speed of the outdoor fan is adjusted to the preset rotating speed.

[0161] It can be seen that the above mainly introduces the scheme provided by the embodiments of the present application from the perspective of method. In order to realize the above functions, the embodiments of the present application provide corresponding hardware structures and / or software modules for executing various functions. Those skilled in the art should easily realize that the modules and algorithm steps of the examples described in combination with the embodiments disclosed in the present text can be realized in the form of hardware or a combination of hardware and computer software. Whether a certain function is realized in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical scheme. Professional technicians can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0162] The embodiments of the present application also provide a computer readable storage medium, including computer execution instructions, when running on a computer, causing the computer to execute the control method of any one of the air conditioning systems provided by the above embodiments.

[0163] The embodiments of the present application also provide a computer program product including computer execution instructions, when running on a computer, causing the computer to execute the control method of any one of the air conditioning systems provided by the above embodiments.

[0164] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any change or replacement within the technical scope disclosed by the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An air conditioning system, characterized by, Comprise: An outdoor unit and at least one indoor unit; the outdoor unit comprises: a compressor, a solenoid valve, a first expansion valve, a second expansion valve, an outdoor fan, a first heat exchanger and a second heat exchanger; the indoor unit comprises a third heat exchanger; The gas outlet end of the compressor is connected to the first end of the first expansion valve and the second heat exchanger; The second end of the first expansion valve is connected to the first end of the solenoid valve and the first heat exchanger; The first end of the second expansion valve is connected to the second heat exchanger, and the second end is connected to the third heat exchanger; The second end of the solenoid valve is connected to the third heat exchanger and a gas-liquid separator; The controller is configured to: In the case of the air conditioning system running the hot water mode, obtain the operating parameters of the air conditioning system; According to the operating parameters, determine whether the air conditioning system meets the defrosting condition; In the case of meeting the defrosting condition, control the solenoid valve to close and the first expansion valve to open, so that the air conditioning system starts defrosting; In the case of the air conditioning system running the cooling mode and the hot water mode, obtain the indoor unit load; the indoor unit load is the load generated when the user set temperature is inconsistent with the current indoor environment temperature; When the indoor unit load is equal to the preset load, control the solenoid valve to close and the second expansion valve to open, and adjust the opening degree of the first expansion valve to a first preset opening degree; or, When the indoor unit load is greater than the preset load, control the solenoid valve to close, and adjust the opening degree of the first expansion valve to a second preset opening degree, the opening degree of the second expansion valve to a third preset opening degree, and the rotating speed of the outdoor fan to a preset rotating speed; or, When the indoor unit load is less than the preset load, control the first expansion valve to close and the solenoid valve to open, and adjust the opening degree of the second expansion valve to a fourth preset opening degree.

2. The air conditioning system of claim 1, wherein, The controller is further configured to: In the case of the air conditioning system running the hot water mode, control the solenoid valve to open and the first expansion valve to close.

3. The air conditioning system of claim 2, wherein, The controller is further configured to: In the case of the air conditioning system running the cooling mode, control the first expansion valve to open and the solenoid valve to close.

4. The air conditioning system according to any one of claims 1 to 3, wherein The air conditioning system further comprises: A circulating water pump connected with the second heat exchanger to form a water system, for providing power for the circulation of water in the water system; A temperature sensor arranged on the first heat exchanger for detecting the environment temperature; A high-pressure pressure sensor arranged on the exhaust pipe of the compressor for detecting the high-pressure pressure of the air conditioning system; The controller is further configured to: Obtain the environment temperature through the temperature sensor and the high-pressure pressure of the air conditioning system through the high-pressure pressure sensor; In the case of the environment temperature being greater than or equal to a preset temperature and the high-pressure pressure being greater than or equal to a preset threshold, control the second expansion valve to throttle and the circulating water pump to open; or, In the case of the environment temperature being greater than or equal to a preset temperature and the high-pressure pressure being less than a preset threshold, control the second expansion valve and the circulating water pump to close.

5. The air conditioning system of claim 4, wherein, The controller is further configured to: In a case where the ambient temperature is less than a preset temperature, the second expansion valve and the circulating water pump are controlled to be closed.

6. A control method of an air conditioning system, characterized by, The application is applied to an air conditioning system, which comprises an outdoor unit and at least one indoor unit; the outdoor unit comprises a compressor, a solenoid valve, a first expansion valve, a second expansion valve, an outdoor fan, a first heat exchanger and a second heat exchanger; the indoor unit comprises a third heat exchanger; An air outlet end of the compressor is connected to a first end of the first expansion valve and the second heat exchanger; A second end of the first expansion valve is connected to the first heat exchanger and a first end of the solenoid valve; A first end of the second expansion valve is connected to the second heat exchanger, and a second end thereof is connected to the third heat exchanger; A second end of the solenoid valve is connected to the third heat exchanger and a gas-liquid separator; The method comprises: In a case where the air conditioning system operates in a hot water mode, an operating parameter of the air conditioning system is acquired; According to the operating parameter, it is determined whether the air conditioning system satisfies a defrosting condition; In a case where the defrosting condition is satisfied, the solenoid valve is controlled to be closed and the first expansion valve is controlled to be opened, so that the air conditioning system starts defrosting; In a case where the air conditioning system operates in a cooling mode and a hot water mode, an indoor unit load is acquired; the indoor unit load is a load generated when a user-set temperature is inconsistent with a current indoor ambient temperature; In a case where the indoor unit load is equal to a preset load, the solenoid valve is controlled to be closed and the second expansion valve is controlled to be opened, and an opening degree of the first expansion valve is adjusted to a first preset opening degree; or In a case where the indoor unit load is greater than the preset load, the solenoid valve is controlled to be closed, an opening degree of the first expansion valve is adjusted to a second preset opening degree, an opening degree of the second expansion valve is adjusted to a third preset opening degree, and a rotating speed of the outdoor fan is adjusted to a preset rotating speed; or In a case where the indoor unit load is less than the preset load, the first expansion valve is controlled to be closed and the solenoid valve is controlled to be opened, and an opening degree of the second expansion valve is adjusted to a fourth preset opening degree.

7. The method of claim 6, wherein, The method further comprises: In a case where the air conditioning system operates in the hot water mode, the solenoid valve is controlled to be opened and the first expansion valve is controlled to be closed.

8. The method of claim 6, wherein, The method further comprises: In a case where the air conditioning system operates in the cooling mode, the first expansion valve is controlled to be opened and the solenoid valve is controlled to be closed.

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