A multi-split air conditioning system

Abstract

The application discloses a multi-connected air conditioner system, relates to the technical field of home appliances, and can make the recovery and utilization of leaked refrigerant more thorough. The multi-connected air conditioner system comprises an outdoor unit, an indoor heat exchanger and a refrigerant recovery device. The outdoor unit comprises a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve; the indoor unit set comprises a plurality of parallel indoor units, each indoor unit comprises an indoor heat exchanger and an indoor expansion valve, and the indoor heat exchanger is connected with the four-way valve through a first pipeline; the refrigerant recovery device comprises a first electromagnetic valve, a second electromagnetic valve, a third electromagnetic valve, a first expansion valve and a liquid storage tank; a first opening of the liquid storage tank is connected with the outdoor expansion valve through the first electromagnetic valve, a second opening of the liquid storage tank is connected with the indoor expansion valve through the second electromagnetic valve, and a third opening of the liquid storage tank is communicated with the first pipeline through the first expansion valve; a first end of the third electromagnetic valve is connected with the outdoor expansion valve, and a second end of the third electromagnetic valve is connected with the indoor expansion valve.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of household appliances, and in particular to a multi-split air conditioning system. BACKGROUND

[0002] With the development of the economy and society, air conditioners are increasingly widely used in entertainment, home and work, and other places. When multiple small areas in the same area need to use air conditioners, in view of the saving of electric energy, a multi-split air conditioning system composed of one outdoor unit and multiple indoor units is often used to achieve the regulation and control of the room temperature of multiple areas. In the use of the multi-split air conditioning system, a heat transfer pipe (such as a copper pipe or an aluminum pipe) on a heat exchanger is used for heat transfer. However, the heat transfer pipe is exposed to the outdoor environment for a long time and may be corroded, which may cause refrigerant leakage.

[0003] To avoid the risk of refrigerant leakage, a pair of electronic expansion valves is added to the inlet and outlet of each indoor unit of the multi-split air conditioning system in the related art to block the refrigerant leaked in the indoor unit from flowing into the indoor environment. However, in the above-mentioned related art, the leaked refrigerant cannot be completely recovered and utilized, and may be directly discharged into the outdoor environment to cause environmental pollution. SUMMARY

[0004] Embodiments of the present application provide a multi-split air conditioning system for more complete recovery and utilization of leaked refrigerant to improve the environmental protection and energy saving of the multi-split air conditioning system.

[0005] In a first aspect, embodiments of the present application provide a multi-split air conditioning system, comprising: an outdoor unit, the outdoor unit comprising a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve; an indoor unit group, the indoor unit group comprising a plurality of indoor units connected in parallel, each indoor unit comprising an indoor heat exchanger and an indoor expansion valve, the indoor heat exchanger being connected to the four-way valve through a first pipe; a refrigerant recovery device, the refrigerant recovery device comprising: a first electromagnetic valve, a second electromagnetic valve, a third electromagnetic valve, a first expansion valve, and a liquid storage tank; a first opening of the liquid storage tank being connected to the outdoor expansion valve through the first electromagnetic valve, a second opening of the liquid storage tank being connected to the indoor expansion valve through the second electromagnetic valve, a third opening of the liquid storage tank being in communication with the first pipe through the first expansion valve, the third opening of the liquid storage tank being arranged at the bottom of the liquid storage tank; a first end of the third electromagnetic valve being connected to the outdoor expansion valve, and a second end of the third electromagnetic valve being connected to the indoor expansion valve.

[0006] The technical scheme provided by the embodiments of the present application brings at least the following beneficial effects: in the multi-split air conditioning system, the refrigerant recovery device is arranged between the outdoor unit and the indoor unit group. When refrigerant leakage occurs, the closing and opening states of the first electromagnetic valve, the second electromagnetic valve and the third electromagnetic valve in the refrigerant recovery device and the closing and opening state of the first expansion valve are controlled in combination with the running modes to be entered by the outdoor unit and the indoor unit group, so that the direction of the refrigerant flow in the multi-split air conditioning system is controlled, the refrigerant in the multi-split air conditioning system is introduced into the liquid storage tank of the refrigerant recovery device from the first opening or the second opening, and the leaked refrigerant is completely recovered, thereby avoiding the problem that the refrigerant is discharged into the outdoor environment to pollute the environment, and the environmental protection performance of the multi-split air conditioning system is improved. Further, when the multi-split air conditioning system enters the normal refrigeration or heating running mode again after the refrigerant leakage is repaired, the refrigerant recovered by the refrigerant recovery device is released into the first pipeline of the multi-split air conditioning system from the third opening, the recovered refrigerant is reasonably utilized, the consumption of refrigerant resources is saved, and the environmental protection performance of the multi-split air conditioning system is improved.

[0007] In addition, in order to improve the release efficiency of the released refrigerant, the third opening is usually arranged at the bottom of the liquid storage tank.

[0008] In some embodiments, the multi-split air conditioning system has multiple working modes, and the multiple working modes include a first refrigerant recovery mode, a second refrigerant recovery mode and a refrigerant release mode. When the multi-split air conditioning system is in the first refrigerant recovery mode, the outdoor heat exchanger works as a condenser, the indoor heat exchanger works as an evaporator, the first electromagnetic valve is in an open state, the second electromagnetic valve is in a closed state, the third electromagnetic valve is in a closed state, and the first expansion valve is in a closed state. When the multi-split air conditioning system is in the second refrigerant recovery mode, the outdoor heat exchanger works as an evaporator, the indoor heat exchanger works as a condenser, the first electromagnetic valve is in a closed state, the second electromagnetic valve is in an open state, the third electromagnetic valve is in a closed state, and the first expansion valve is in a closed state. When the multi-split air conditioning system is in the refrigerant release mode, the first electromagnetic valve is in a closed state, the second electromagnetic valve is in a closed state, the third electromagnetic valve is in an open state, the first expansion valve is in an open state, one of the outdoor heat exchanger and the indoor heat exchanger works as an evaporator, and the other works as a condenser.

[0009] Based on this, the multi-split air conditioning system can provide a working mode corresponding to different scenes. Specifically, when it is necessary to recover the refrigerant leaked by the indoor unit, the multi-split air conditioning system can be switched to the first refrigerant recovery mode, and the refrigerant leaked by the indoor unit is recovered by the refrigerant recovery device. When it is necessary to recover the refrigerant leaked by the outdoor unit, the multi-split air conditioning system can be switched to the second refrigerant recovery mode, and the refrigerant leaked by the outdoor unit is recovered by the refrigerant recovery device. When it is necessary to utilize the refrigerant recovered by the refrigerant recovery device, the multi-split air conditioning system can be adjusted to the refrigerant release mode, and the recovered refrigerant is released into the first pipeline for use by the multi-split air conditioning system during refrigeration operation or heating operation.

[0010] It should be noted that the plurality of working modes also include a refrigeration mode and a heating mode. Specifically, when refrigeration is needed (e.g., the room temperature is too high), the operating mode of the multi-split air conditioning system is switched to the refrigeration mode to reduce the indoor environment temperature. When heating is needed (e.g., the room temperature is too low), the operating mode of the multi-split air conditioning system is switched to the heating mode to increase the indoor environment temperature.

[0011] In addition, when the multi-split air conditioning system is in the refrigeration working mode and the recovered refrigerant needs to be released, the outdoor heat exchanger works as a condenser, the indoor heat exchanger works as an evaporator, the first electromagnetic valve is in a closed state, the second electromagnetic valve is in a closed state, the third electromagnetic valve is in an open state, and the first expansion valve is in an open state. When the multi-split air conditioning system is in the heating working mode and the refrigerant recovered by the recovery device needs to be released, the outdoor heat exchanger works as an evaporator, the indoor heat exchanger works as a condenser, the first electromagnetic valve is in a closed state, the second electromagnetic valve is in a closed state, the third electromagnetic valve is in an open state, and the expansion valve is in an open state.

[0012] In some embodiments, the refrigerant recovery device further includes a first subcooling heat exchanger, the first subcooling heat exchanger including a first passage and a second passage; the third opening of the liquid storage tank is in communication with the first pipeline through the first expansion valve and the first passage of the first subcooling heat exchanger in sequence; and the first end of the third electromagnetic valve is connected with the outdoor expansion valve through the second passage of the first subcooling heat exchanger.

[0013] Based on this, the refrigerant recovered by the refrigerant recovery device flows through the first channel of the first cold heat exchanger, and the multi-split air conditioning system flows through the second channel of the first cold heat exchanger during operation. The second channel cools the refrigerant flowing through the second channel to release corresponding heat. The first channel uses the heat released by the second channel to heat the recovered refrigerant flowing through the first channel, so that the liquid refrigerant in the recovered refrigerant of two-phase state (gas state and liquid state) is converted into gas state refrigerant, reducing the content of liquid refrigerant in the refrigerant released by the refrigerant recovery device, and increasing the content of gas state refrigerant in the recovered refrigerant released, to ensure the use efficiency of the recovered refrigerant.

[0014] It should be noted that, on the one hand, during the process of releasing the recovered refrigerant in the multi-split air conditioning system in the refrigeration mode, the refrigerant recovery device releases the recovered refrigerant to the compressor of the outdoor unit, and the content of liquid refrigerant in the refrigerant released by the refrigerant recovery device is reduced, which reduces the liquid return of the compressor and improves the service life of the compressor. On the other hand, during the process of releasing the recovered refrigerant in the multi-split air conditioning system in the heating mode, the refrigerant recovery device releases the recovered refrigerant to the indoor heat exchanger of the indoor unit, and the content of gas state refrigerant in the recovered refrigerant released is increased, which increases the amount of recovered refrigerant entering the indoor heat exchanger and improves the utilization rate of the recovered refrigerant.

[0015] In some embodiments, the refrigerant recovery device further comprises a first temperature sensor for detecting the temperature value of the refrigerant flowing out of the first channel of the first supercooling heat exchanger; the outdoor unit further comprises a gas-liquid separator and a first outdoor pressure sensor for detecting the pressure value of the refrigerant at the inlet of the gas-liquid separator; the multi-split air conditioning system further comprises a controller configured to: when the multi-split air conditioning system operates in the refrigerant release mode, obtain the first temperature value detected by the first temperature sensor and the pressure value detected by the first outdoor pressure sensor; if the difference between the first temperature value and the second temperature value is greater than or equal to the first preset temperature value, control the first expansion valve to increase the opening degree, and the second temperature value is the saturation temperature value corresponding to the pressure value detected by the first outdoor pressure sensor; or, if the difference between the first temperature value and the second temperature value is greater than the first preset temperature value, control the first expansion valve to reduce the opening degree.

[0016] In this embodiment, the temperature difference between the first temperature value and the saturation temperature value is obtained by comparing the first temperature value of the refrigerant flowing out of the first channel of the first subcooling heat exchanger with the saturation temperature (i.e., the second temperature value) corresponding to the pressure value of the refrigerant at the inlet of the gas-liquid separator. The opening of the first expansion valve is controlled based on the relationship between the temperature difference and the first preset temperature value to ensure that the opening of the first expansion valve is within a reasonable range, thereby ensuring that the amount of refrigerant released by the refrigerant recovery device is within a reasonable range. On the one hand, it avoids the refrigerant recovery device from releasing too much refrigerant, resulting in too much refrigerant in the pipeline of the entire multi-split air-conditioning system, which leads to the multi-split air-conditioning system not processing the refrigerant in time; on the other hand, it avoids the refrigerant recovery device from releasing too little refrigerant, resulting in too little refrigerant in the pipeline of the entire multi-split air-conditioning system, which reduces the working efficiency of the multi-split air-conditioning system, such as reducing the cooling speed or heating speed.

[0017] In some embodiments, the refrigerant recovery device also includes a throttling device and a second subcooling heat exchanger; the second subcooling heat exchanger includes a third channel and a fourth channel; the third opening of the liquid storage tank is also connected to the first pipeline through the throttling device and the third channel of the second subcooling heat exchanger in sequence; the second end of the third solenoid valve is connected to the indoor expansion valve through the fourth channel of the second subcooling heat exchanger.

[0018] Based on this, the refrigerant recovered in the refrigerant recovery device is throttled by the throttling device and flows through the third channel of the cold heat exchanger; during the operation of the multi-split air-conditioning system, the refrigerant flows through the fourth channel of the cold heat exchanger. The fourth channel cools the refrigerant flowing through the fourth channel to release the corresponding heat. The third channel uses the heat released by the fourth channel to heat the recovered refrigerant flowing through the third channel, so that the liquid refrigerant in the two-phase (gaseous and liquid) recovered refrigerant is converted into gaseous refrigerant, reducing the content of liquid refrigerant in the refrigerant released by the refrigerant recovery device and increasing the content of gaseous refrigerant in the released recovered refrigerant to ensure the use efficiency of the recovered refrigerant.

[0019] In some embodiments, the refrigerant recovery device also includes a second temperature sensor, which is used to detect the temperature value of the refrigerant flowing out of the third channel of the second subcooling heat exchanger; the controller is also configured to: when the multi-split air-conditioning system operates in the refrigerant release mode, obtain the third temperature value detected by the second temperature sensor and the pressure value detected by the first outdoor pressure sensor; if the difference between the third temperature value and the second temperature value is greater than or equal to the second preset temperature value, then end the operation of the refrigerant release mode, and the second temperature value is the saturation temperature value corresponding to the pressure value detected by the first outdoor pressure sensor; or, if the difference between the third temperature value and the second temperature value is less than the second preset temperature value, then continue to operate the refrigerant release mode.

[0020] In this embodiment, the temperature difference between the first temperature value of the refrigerant flowing out of the third passage of the second subcooling heat exchanger and the second temperature value corresponding to the pressure value of the refrigerant at the inlet of the gas-liquid separator is obtained by comparing the first temperature value with the second temperature value. Based on the size relationship between the temperature difference and the second preset temperature value, the release process of the refrigerant recovery device is reasonably controlled to ensure that the refrigerant recovery device can only release refrigerant when there is sufficient refrigerant, thereby avoiding the situation that the refrigerant recovery device still executes the refrigerant release mode when there is no refrigerant in the refrigerant recovery device, so that the amount of refrigerant in the multi-split air conditioning system is abnormally small, thereby reducing the working efficiency of the multi-split air conditioning system.

[0021] In some embodiments, the refrigerant recovery device further comprises a fourth electromagnetic valve, the fourth electromagnetic valve is arranged on the first pipeline, a first end of the fourth electromagnetic valve is connected with the four-way valve, and a second end of the fourth electromagnetic valve is connected with the indoor heat exchanger.

[0022] Based on this, when the multi-split air conditioning system is in any one of the refrigeration mode, the heating mode, the first refrigerant recovery mode, the second refrigerant recovery mode, and the refrigerant release mode, the fourth electromagnetic valve is controlled to be in an open state to ensure that the refrigerant can circulate in the corresponding pipeline.

[0023] It should be noted that the controller is further configured to: in the first refrigerant recovery mode and the second refrigerant recovery mode, when the refrigerant recovery stop condition is met, the fourth electromagnetic valve is controlled to be closed; wherein the refrigerant recovery stop condition comprises one or more of the following: the duration of the multi-split air conditioning system operating in the first refrigerant recovery mode or the second refrigerant recovery mode reaches a preset duration; or the pressure of the refrigerant entering the compressor is within a preset pressure range. Based on this, by setting the refrigerant recovery stop condition, the timing of ending the refrigerant recovery can be determined, so that the refrigerant is recovered when the amount of refrigerant in the pipeline of the multi-split air conditioning system is within a reasonable range, thereby avoiding the situation that the first refrigerant recovery mode or the second refrigerant recovery mode is still executed when there is no refrigerant in the pipeline of the multi-split air conditioning system, causing the multi-split air conditioning system to be abnormal or damaged, and thereby improving the safety and service life of the multi-split air conditioning system.

[0024] In some embodiments, the refrigerant recovery device further comprises a fifth electromagnetic valve, the fifth electromagnetic valve is arranged on the first pipeline, a first end of the fifth electromagnetic valve is connected with the second end of the fourth electromagnetic valve, and a second end of the fifth electromagnetic valve is connected with the indoor heat exchanger.

[0025] Based on this, when the multi-split air conditioning system is in any one of the refrigeration mode, the heating mode, the first refrigerant recovery mode, the second refrigerant recovery mode, and the refrigerant release mode, the fifth electromagnetic valve is controlled to be in an open state to ensure that the refrigerant can circulate in the corresponding pipeline.

[0026] It should be noted that the controller is further configured to: in the first refrigerant recovery mode or the second refrigerant recovery mode, when the refrigerant recovery stop condition is met, control the fifth electromagnetic valve to be closed; wherein the refrigerant recovery stop condition includes one or more of the following: the multi-split air conditioning system has run in the first refrigerant recovery mode or the second refrigerant recovery mode for a preset time length; or the pressure of the refrigerant entering the compressor is within a preset pressure range. Based on this, the indoor unit corresponding to the indoor unit that leaks refrigerant in the indoor unit group is in a closed state. After the refrigerant recovery is completed, by controlling the fourth electromagnetic valve and the fifth electromagnetic valve to be closed, the indoor unit that leaks refrigerant in the indoor unit group is all free from the refrigerant recovery device and the outdoor unit, so as to not be affected by the refrigerant recovery device and the outdoor unit during replacement of the indoor unit that leaks refrigerant, and the convenience of installing or replacing the indoor unit is improved.

[0027] In some embodiments, the refrigerant recovery device further comprises a second expansion valve, a first end of the second expansion valve is connected with the fourth opening of the liquid storage tank, and a second end of the second expansion valve is in communication with the second pipeline, the second pipeline being a pipeline between the fourth electromagnetic valve and the fifth electromagnetic valve; or the first end of the second expansion valve is in communication with the third pipeline, and the second end of the second expansion valve is in communication with the second pipeline, the third pipeline being a pipeline between the first electromagnetic valve and the first opening of the liquid storage tank.

[0028] In this embodiment, during the refrigerant recovery process, the amount of refrigerant circulating in the multi-split air conditioning system becomes less and less, and the low pressure of the multi-split air conditioning system becomes closer and closer to the case where it is within a preset pressure range (usually referring to the atmospheric pressure of the environment in which the multi-split air conditioning system is located). In this case, the discharge temperature of the compressor will become higher and higher, which will affect the reliability of the compressor. Based on this, a second expansion valve is added between the first electromagnetic valve and the fourth electromagnetic valve, or a second expansion valve is added between the fourth electromagnetic valve and the liquid storage tank. During the refrigerant recovery process, the second expansion valve is opened to bypass a part of the refrigerant to the compressor, which is used to reduce the discharge temperature of the compressor, thereby reducing the temperature of the compressor, to ensure the reliability of the compressor during the refrigerant recovery process.

[0029] In addition, during the refrigerant recovery process, the refrigerant entering the liquid storage tank can be two-phase refrigerant of gas and liquid states. In the case where the refrigerant entering the liquid storage tank is two-phase refrigerant, the average density of the two-phase refrigerant is small, so the amount of refrigerant stored in the liquid storage tank will be reduced, thereby affecting the effect of refrigerant recovery. Therefore, during the refrigerant recovery process, the expansion valve is opened to bypass the gaseous refrigerant to enter, so as to improve the effect of refrigerant recovery.

[0030] In some embodiments, the refrigerant recovery device further includes: a first stop valve, the first stop valve being arranged on the pipeline between the four-way valve and the fourth solenoid valve, the first end of the first stop valve being connected to the four-way valve through a pipeline, and the second end of the first stop valve being connected to the first end of the fourth solenoid valve through a pipeline; a second stop valve, the second stop valve being arranged on the pipeline between the fourth solenoid valve and the indoor heat exchanger, the first end of the second stop valve being connected to the second end of the fourth solenoid valve through a pipeline, and the second end of the second stop valve being connected to the indoor heat exchanger in each indoor unit through a pipeline; a third stop valve, the third stop valve being arranged on the pipeline between the outdoor expansion valve and the first solenoid valve, the first end of the third stop valve being connected to the outdoor expansion valve through a pipeline, and the second end of the third stop valve being connected to the first end of the first solenoid valve through a pipeline; a fourth stop valve, the fourth stop valve being arranged on the pipeline between the second solenoid valve and the indoor heat exchanger, the first end of the fourth stop valve being connected to the second end of the second solenoid valve through a pipeline, and the second end of the fourth stop valve being connected to the indoor expansion valve in each indoor unit through a pipeline.

[0031] In this embodiment, while the multi-split air conditioning system is operating in the first refrigerant recovery mode or the second refrigerant recovery mode, the first, second, third, and fourth stop valves are in an open state. After the first or second refrigerant recovery mode is complete, the first, second, and third solenoid valves are closed, and the first, second, third, and fourth stop valves are also closed to better prevent the flow of refrigerant in the pipelines corresponding to the stop valves.

[0032] In some embodiments, the outdoor unit further includes: a fifth stop valve, which is arranged on the pipeline between the four-way valve and the first stop valve, the first end of the fifth stop valve is connected to the four-way valve through a pipeline, and the second end of the fifth stop valve is connected to the first end of the first stop valve through a pipeline; a sixth stop valve, which is arranged on the pipeline between the outdoor expansion valve and the third stop valve, the first end of the sixth stop valve is connected to the outdoor expansion valve through a pipeline, and the second end of the sixth stop valve is connected to the first end of the third stop valve through a pipeline.

[0033] In this embodiment, while the multi-split air conditioning system is operating in the first or second refrigerant recovery mode, the fifth and sixth stop valves are open. After the first or second refrigerant recovery mode is complete, the fifth and sixth solenoid valves are closed to better prevent refrigerant from flowing through the pipelines corresponding to the stop valves.

[0034] In some embodiments, the outdoor unit further comprises: a sixth electromagnetic valve, the sixth electromagnetic valve is arranged on the pipeline between the four-way valve and the fifth stop valve, a first end of the sixth electromagnetic valve is connected to the four-way valve through the pipeline, and a second end of the sixth electromagnetic valve is connected to the first end of the fifth stop valve through the pipeline; and a seventh electromagnetic valve, the seventh electromagnetic valve is arranged on the pipeline between the outdoor expansion valve and the sixth stop valve, a first end of the seventh electromagnetic valve is connected to the outdoor expansion valve through the pipeline, and a second end of the seventh electromagnetic valve is connected to the first end of the sixth stop valve through the pipeline.

[0035] Based on the sixth electromagnetic valve and the seventh electromagnetic valve, after the refrigerant recovery is completed, the sixth electromagnetic valve and the seventh electromagnetic valve are controlled to be closed, so that the outdoor unit is freely separated from the refrigerant recovery device and the indoor unit group, thereby avoiding the influence of the refrigerant recovery device and the indoor unit group on the replacement of the outdoor unit, and improving the convenience of installing or replacing the outdoor unit.

[0036] In some embodiments, each indoor unit further comprises an indoor refrigerant leakage detection device; and the multi-split air conditioning system further comprises a controller electrically connected to the indoor refrigerant leakage detection device in each indoor unit; the controller is configured to: acquire detection results of each indoor refrigerant leakage detection device, the detection result of one indoor refrigerant leakage detection device being used to indicate whether the indoor unit where the refrigerant leakage detection device is located has refrigerant leakage; and determine whether there is an indoor unit having refrigerant leakage in the indoor unit group according to the detection results of each indoor refrigerant leakage detection device; and if there is, control the multi-split air conditioning system to run the first refrigerant recovery mode.

[0037] In this way, the multi-split air conditioning system can determine the indoor unit having refrigerant leakage in the indoor unit group through the detection results of the indoor refrigerant leakage detection device. In the case that there is an indoor unit having refrigerant leakage in the indoor unit group, the multi-split air conditioning system is controlled to switch to the first refrigerant recovery mode to recover the refrigerant leaked in the indoor unit to the refrigerant recovery device. On the one hand, this avoids the refrigerant leakage in the indoor unit from causing risks to the indoor environment, thereby improving the safety of the multi-split air conditioning system; on the other hand, the refrigerant recovery device is used to recover the refrigerant, which greatly reduces the amount of refrigerant discharged from the outdoor unit to the outdoor environment, thereby improving the environmental protection performance of the multi-split air conditioning system.

[0038] In some embodiments, the outdoor unit further comprises an outdoor refrigerant leakage detection device, and the controller is electrically connected to the outdoor refrigerant leakage detection device of the outdoor unit; the controller is configured to: acquire a detection result of the outdoor refrigerant leakage detection device, the detection result of the outdoor refrigerant leakage detection device being used to indicate whether the outdoor unit has refrigerant leakage; and if the detection result of the outdoor refrigerant leakage detection device indicates that the outdoor unit has refrigerant leakage, control the multi-split air conditioning system to run the second refrigerant recovery mode.

[0039] In this way, the multi-split air conditioning system can determine whether the outdoor unit has leaked refrigerant through the detection result of the outdoor refrigerant leakage detection device. In the case where the outdoor unit has leaked refrigerant, the multi-split air conditioning system is controlled to switch to the second refrigerant recovery mode and operate, and the refrigerant leaked from the outdoor unit is recovered into the refrigerant recovery device, so that the refrigerant is recovered through the refrigerant recovery device, greatly reducing the amount of refrigerant discharged from the outdoor unit to the outdoor environment, and improving the environmental protection of the multi-split air conditioning system.

[0040] In some embodiments, the controller is further configured to: close the indoor expansion valve in the indoor unit that has leaked refrigerant when the multi-split air conditioning system operates in the first refrigerant recovery mode; and control the outdoor expansion valve to be at a maximum opening value when the multi-split air conditioning system operates in the second refrigerant recovery mode.

[0041] In this embodiment, when the multi-split air conditioning system operates in the first refrigerant recovery mode, the indoor expansion valve in the indoor unit that has leaked refrigerant is closed to prevent the refrigerant from continuing to enter the indoor unit that has leaked refrigerant, thereby avoiding the refrigerant in the indoor unit that has leaked refrigerant from leaking into the indoor environment, and further ensuring the safe use of the multi-split air conditioning system by the user. When the multi-split air conditioning system operates in the second refrigerant recovery mode, the outdoor expansion valve is controlled to be at a maximum opening value, so that the refrigerant in the pipeline connected to the outdoor expansion valve is more quickly recovered to the refrigerant recovery device through the outdoor unit and the indoor unit, thereby improving the recovery speed of the refrigerant leaked from the outdoor unit and ensuring the refrigerant recovery efficiency of the multi-split air conditioning system.

[0042] In a second aspect, the embodiments of the present application provide a control method of a multi-split air conditioning system, applied to the multi-split air conditioning system of the first aspect, and the method comprises:

[0043] In response to a start signal of the multi-split air conditioning system, when it is detected that there is refrigerant in the liquid storage tank of the refrigerant recovery device, the multi-split air conditioning system is controlled to be in a refrigerant release mode.

[0044] When the multi-split air conditioning system is in the refrigerant release mode, the first electromagnetic valve is in a closed state, the second electromagnetic valve is in a closed state, the third electromagnetic valve is in an open state, the first expansion valve is in an open state, and one of the outdoor heat exchanger and the indoor heat exchanger works as an evaporator and the other works as a condenser.

[0045] In some embodiments, the refrigerant recovery device further comprises a first subcooling heat exchanger and the outdoor unit further comprises a gas-liquid separator, and the method comprises: obtaining a first temperature value of the refrigerant flowing out of the first subcooling heat exchanger and a pressure value of the refrigerant at the inlet of the gas-liquid separator; if a difference between the first temperature value and a second temperature value is greater than or equal to a first preset temperature value, controlling the first expansion valve to increase the opening degree, the second temperature value being a saturation temperature value corresponding to the pressure value of the refrigerant at the inlet of the gas-liquid separator; or, if the difference between the first temperature value and the second temperature value is greater than the first preset temperature value, controlling the first expansion valve to decrease the opening degree.

[0046] In some embodiments, the refrigerant recovery device further comprises a second subcooling heat exchanger, and the method further comprises: when the multi-split air conditioning system is running in the refrigerant release mode, obtaining a third temperature value of the refrigerant flowing out of the third passage of the second subcooling heat exchanger and a pressure value of the refrigerant at the inlet of the gas-liquid separator; if a difference between the third temperature value and the second temperature value is greater than or equal to a second preset temperature value, ending the running in the refrigerant release mode, the second temperature value being a saturation temperature value corresponding to the pressure value of the refrigerant at the inlet of the gas-liquid separator; or, if the difference between the third temperature value and the second temperature value is less than the second preset temperature value, continuing the running in the refrigerant release mode.

[0047] In a third aspect, the embodiments of the present application provide a controller of a multi-split air conditioning system, 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 method provided in the second aspect and possible implementation manners.

[0048] In a fourth aspect, the embodiments of the present application provide a computer readable storage medium, the computer readable storage medium comprising computer instructions, when the computer instructions run on a computer, the computer instructions make the computer execute the method provided in the second aspect and possible implementation manners.

[0049] In a fifth aspect, the embodiments of the present application provide a computer program product comprising computer instructions, when the computer instructions run on a computer, the computer instructions make the computer execute the method provided in the second aspect and possible implementation manners.

[0050] It should be noted that the above computer instructions 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 this.

[0051] The beneficial effects of the second aspect to the fifth aspect described in the present application can be referred to the beneficial effect analysis of the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0052] The accompanying drawings are included to provide a further understanding of the technical solutions of the present application, constitute a part of the specification and are used to explain the technical solutions of the present application together with the embodiments of the present application, and do not constitute a limitation on the technical solutions of the present application.

[0053] FIG. 1 A structural schematic diagram of a multi-split air conditioning system according to some embodiments;

[0054] FIG. 2 A structural schematic diagram of another multi-split air conditioning system according to some embodiments;

[0055] FIG. 3 A structural schematic diagram of another multi-split air conditioning system according to some embodiments;

[0056] FIG. 4 A structural schematic diagram of another multi-split air conditioning system according to some embodiments;

[0057] FIG. 5 A structural schematic diagram of another multi-split air conditioning system according to some embodiments;

[0058] FIG. 6 A control flowchart of a multi-split air conditioning system according to some embodiments;

[0059] FIG. 7 A control flowchart of another multi-split air conditioning system according to some embodiments;

[0060] FIG. 8 A refrigerant circulation principle schematic diagram of a multi-split air conditioning system according to some embodiments;

[0061] FIG. 9 A refrigerant circulation principle schematic diagram of another multi-split air conditioning system according to some embodiments;

[0062] FIG. 10 A refrigerant circulation principle schematic diagram of another multi-split air conditioning system according to some embodiments;

[0063] FIG. 11 A refrigerant circulation principle schematic diagram of another multi-split air conditioning system according to some embodiments;

[0064] FIG. 12 A refrigerant circulation principle schematic diagram of another multi-split air conditioning system according to some embodiments;

[0065] FIG. 13 A refrigerant circulation principle schematic diagram of another multi-split air conditioning system according to some embodiments;

[0066] FIG. 14 Structure diagram of another multi-split air conditioning system according to some embodiments;

[0067] FIG. 15 Control flow diagram of a multi-split air conditioning system according to some embodiments;

[0068] FIG. 16 Control flow diagram of another multi-split air conditioning system according to some embodiments;

[0069] FIG. 17 Hardware structure diagram of a controller according to some embodiments.

[0070] Reference signs: 100-multi-split air conditioning system; 200-outdoor unit: 201-compressor; 202-four-way valve; 203-outdoor heat exchanger; 204-outdoor expansion valve; 205-gas-liquid separator; 206-oil separator; 207-oil return capillary; 208-outdoor check valve; 209-first outdoor pressure sensor; 210-second outdoor pressure sensor; 211-fifth stop valve; 212-sixth stop valve; 213-sixth solenoid valve; 214-seventh solenoid valve; 215-outdoor fan; 300-indoor unit; 300A-first indoor unit; 300B-second indoor unit; 301A-first indoor heat exchanger; 302A-first indoor expansion valve; 303A-first indoor fan; 301B-second indoor heat exchanger; 302B-second indoor expansion valve; 303B-second indoor fan; seventh stop valve 304; eighth stop valve 305; 400- refrigerant recovery device; 401-first solenoid valve; 402-second solenoid valve; 403-third solenoid valve; 404-liquid storage tank; 405-fourth solenoid valve; 406-fifth solenoid valve; 407-first stop valve; 408-second stop valve; 409-third stop valve; 410-fourth stop valve; 411-first expansion valve; 412-second expansion valve; 413-first subcooling heat exchanger; 414-throttling device; 415-second subcooling heat exchanger; 416-first passage; 417-second passage; 418-third passage; 419-fourth passage. DETAILED DESCRIPTION

[0071] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0072] The terms "first", "second", etc. are used only for the purpose of description and do not imply or suggest relative importance or a number of the technical features indicated. Thus, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0073] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, 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, the "connected" and "connected" used in the present application have the meaning of conducting. The specific meaning needs to be understood in combination with the context.

[0074] Unless otherwise required by the context, the term "comprise" and other forms such as "comprises", "comprises" and "comprises" are interpreted as open, inclusive meaning, i.e. "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" and the like are intended to indicate that the specific features, structures, materials or characteristics related to the embodiment or example are included in at least one embodiment or example of the present disclosure. The illustrative representation of the above terms does not necessarily mean the same embodiment or example. In addition, the specific features, structures, materials or characteristics can be included in any one or more embodiments or examples in any appropriate manner.

[0075] In the embodiments of the present application, the words "exemplary" or "for example" are used to mean serving as an example, instance, or illustration. Any embodiment or design presented as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Rather, the use of "exemplary" or "for example" is intended to present concepts in a particular manner. The term "exemplary" or "for example" is used to present concepts in a particular manner.

[0076] As described in the background, in order to avoid the risk of refrigerant leakage, a pair of electronic expansion valves is added to the inlet and outlet of each indoor unit in a multi-split air conditioning system to block the leakage of refrigerant in the indoor unit from flowing into the indoor environment. However, in the above-mentioned related art, the leaked refrigerant cannot be completely recovered and utilized, and may be directly discharged into the outdoor environment, causing environmental pollution.

[0077] To this end, the embodiments of the present application provide a multi-split air conditioning system. In the multi-split air conditioning system, a refrigerant recovery device is arranged between the outdoor unit and the indoor unit group. When refrigerant leakage occurs, the closing and opening states of the first, second and third electromagnetic valves in the refrigerant recovery device and the closing and opening state of the first expansion valve are controlled according to the operating mode of the outdoor unit and the indoor unit group, so as to control the direction of the refrigerant flow in the multi-split air conditioning system. The refrigerant in the multi-split air conditioning system is introduced into the liquid storage tank of the refrigerant recovery device from the first opening or the second opening, so as to completely recover the leaked refrigerant, thereby avoiding the problem of environmental pollution caused by the discharge of refrigerant into the outdoor environment, and further improving the environmental protection of the multi-split air conditioning system. Furthermore, when the multi-split air conditioning system enters the normal cooling or heating operating mode again after the refrigerant leakage is repaired, the refrigerant recovered by the refrigerant recovery device is released from the third opening into the first pipeline of the multi-split air conditioning system, so as to reasonably utilize the recovered refrigerant, save the consumption of refrigerant resources, and improve the environmental protection of the multi-split air conditioning system.

[0078] In addition, in order to improve the release efficiency of the released refrigerant, the third opening is usually arranged at the bottom of the liquid storage tank.

[0079] To further describe the scheme of the present application, as shown in FIG. 1 FIG. 1 is a structural schematic diagram of a multi-split air conditioning system provided by an embodiment of the present application.

[0080] Outdoor unit 200

[0081] Referring to FIG. 1 The multi-split air conditioning system 100 includes an outdoor unit 200, a plurality of indoor units (such as FIG. 1 a first indoor unit 300A and a second indoor unit 300B) in an indoor unit group 300, and a refrigerant recovery device 400.

[0082] The outdoor unit 200 includes, in sequence, a compressor 201, a four-way valve 202, an outdoor heat exchanger 203, and an outdoor expansion valve 204.

[0083] In some embodiments, the outdoor unit 200 further includes a gas-liquid separator 205, an oil separator 206, an oil return capillary tube 207, and an outdoor one-way valve 208.

[0084] In detail, as shown in FIG. 1 , an outlet of the compressor 201 is connected to a first end of the oil separator 206 through a pipeline, a second end of the oil separator 206 is connected to the outdoor one-way valve 208 through a pipeline, the outdoor one-way valve 208 is connected to the four-way valve 202 through a pipeline, the four-way valve 202 is connected to the outdoor heat exchanger 203 through a pipeline, and the outdoor heat exchanger 203 is connected to the outdoor expansion valve 204 through a pipeline. Among them, a third end of the oil separator 206 is connected to a first opening of the gas-liquid separator 205 through a pipeline; a second opening of the gas-liquid separator 205 is connected to the four-way valve 202 through a pipeline.

[0085] In some other embodiments, the outdoor unit 200 further comprises an outdoor refrigerant leakage detection device (not shown in the figure).

[0086] In some other embodiments, the outdoor unit 200 further comprises a first outdoor pressure sensor 209 and a second outdoor pressure sensor 210, wherein the first outdoor pressure sensor 209 is arranged at a first port of the gas-liquid separator 205 and is used to detect the pressure of the refrigerant entering the compressor 201, as shown in FIG. 1 , the pressure of the refrigerant entering the compressor 201 is characterized by detecting the pressure value of the refrigerant at the inlet of the gas-liquid separator through the first outdoor pressure sensor 209; the second outdoor pressure sensor 210 is arranged at the pipeline connecting the outdoor one-way valve 208 and the four-way valve 202, and is used to detect the pressure of the refrigerant flowing out of the compressor 201. Generally, the first outdoor pressure sensor 209 can be a low pressure sensor, and the second outdoor pressure sensor 209 can be a high pressure sensor.

[0087] In some embodiments, one end of the outdoor heat exchanger 203 is connected to the compressor 201 through the four-way valve 202, and the other end is connected to the refrigerant recovery device 400. The outdoor heat exchanger 203 is used for heat exchange between the refrigerant flowing in the heat transfer pipe of the outdoor heat exchanger 203 and outdoor air. Among them, the compressor 201 is arranged between the indoor heat exchanger and the outdoor heat exchanger 203, and is used to provide power for refrigerant circulation. Taking the refrigeration cycle as an example, the compressor 201 delivers the compressed refrigerant to the outdoor heat exchanger 203 through the four-way valve 202.

[0088] Optionally, the compressor 201 can be an inverter compressor 201 with variable capacity based on speed control of an inverter.

[0089] In some embodiments, as shown in FIG. 1The four ports (i.e., the C port, the D port, the S port and the E port) of the four-way valve 202 are respectively connected to the discharge port of the compressor 201, the outdoor heat exchanger 203, the suction port of the compressor 201 and the indoor heat exchanger of each indoor unit. The four-way valve 202 is used to realize mutual conversion between the cooling mode and the heating mode by changing the flow direction of the refrigerant in the system pipeline.

[0090] In some embodiments, the outdoor unit 200 further comprises an outdoor fan 215, which generates an air flow of outdoor air through the outdoor heat exchanger 203 to facilitate heat exchange between the refrigerant flowing in the heat transfer pipe of the outdoor heat exchanger 203 and the outdoor air.

[0091] In some embodiments, the outdoor unit 200 further comprises an outdoor fan 215 motor (not shown in the figure) connected to the outdoor fan 215 for driving or changing the rotating speed of the outdoor fan 215.

[0092] In some embodiments, the outdoor unit 200 further comprises a high-pressure pressure switch (not shown in the figure) electrically connected to the controller for monitoring the pressure of the multi-split air conditioning system pipeline. When the pipeline pressure of the multi-split air conditioning system is abnormal, the controller is sent an abnormal information to control the system to stop running, so as to ensure the normal operation of the multi-split air conditioning system.

[0093] Based on the above-mentioned embodiments, the outdoor unit 200 is further provided with a sixth electromagnetic valve 213 and a seventh electromagnetic valve 214. The sixth electromagnetic valve 213 is arranged on the pipeline between the four-way valve 202 and the fifth stop valve 211. The first end of the sixth electromagnetic valve 213 is connected to the four-way valve 202 through the pipeline, and the second end of the sixth electromagnetic valve 213 is connected to the first end of the fifth stop valve 211 through the pipeline. The seventh electromagnetic valve 214 is arranged on the pipeline between the outdoor expansion valve 204 and the sixth stop valve 212. The first end of the seventh electromagnetic valve 214 is connected to the outdoor expansion valve 204 through the pipeline, and the second end of the seventh electromagnetic valve 214 is connected to the first end of the sixth stop valve 212 through the pipeline.

[0094] Based on the above-mentioned sixth electromagnetic valve 213 and seventh electromagnetic valve 214, after the refrigerant recovery is completed, the sixth electromagnetic valve 213 and the seventh electromagnetic valve 214 are controlled to be closed, so that the outdoor unit 200 is freely separated from the refrigerant recovery device 400 and the indoor unit group 300, so as to facilitate the replacement of the outdoor unit 200 without being affected by the refrigerant recovery device 400 and the indoor unit group 300, and improve the convenience of installing or replacing the outdoor unit 200.

[0095] Based on the above embodiments, in some embodiments, the outdoor unit 200 further comprises a fifth stop valve 211 and a sixth stop valve 212, wherein the fifth stop valve 211 is arranged on the pipeline between the four-way valve 202 and the first stop valve 407, the first end of the fifth stop valve 211 is connected to the four-way valve 202 through the pipeline, and the second end of the fifth stop valve 211 is connected to the first end of the first stop valve 407 through the pipeline; the sixth stop valve 212 is arranged on the pipeline between the outdoor expansion valve 204 and the third stop valve 409, the first end of the sixth stop valve 212 is connected to the outdoor expansion valve 204 through the pipeline, and the second end of the sixth stop valve 212 is connected to the first end of the third stop valve 409 through the pipeline.

[0096] In this embodiment, during the operation of the multi-split air conditioning system in the first refrigerant recovery mode or the second refrigerant recovery mode, the fifth stop valve 211 and the sixth stop valve 212 described above are in an open state. After the first refrigerant recovery mode or the second refrigerant recovery mode is completed, the fifth stop valve 211 and the sixth stop valve 212 are in a closed state to better prevent the circulation of refrigerant in the pipeline corresponding to the stop valve.

[0097] Indoor unit group 300

[0098] The indoor unit group 300 comprises a plurality of indoor units connected in parallel, each indoor unit comprising an indoor heat exchanger and an indoor expansion valve. Wherein, the indoor heat exchanger is connected to the four-way valve 202 of the outdoor unit through a first pipeline. For example, the first pipeline is as shown in (14)→(15)→(16)→(17)→(18) in FIG. 1. FIG. 1

[0099] In some embodiments, the indoor unit group 300 further comprises an indoor refrigerant leakage detection device corresponding to each indoor unit. The indoor refrigerant leakage detection device (not shown in the figure) is used to detect whether the indoor unit of the indoor unit group 300 corresponding to the indoor refrigerant leakage detection device leaks refrigerant. The indoor refrigerant leakage detection device is commonly referred to as an indoor refrigerant leakage detection sensor.

[0100] For example, the first indoor unit 300A comprises a first indoor heat exchanger 301A, a first indoor expansion valve 302A, and a first indoor refrigerant leakage detection device.

[0101] In some embodiments, the first indoor unit 300A further comprises a first indoor liquid pipe temperature sensor, a first indoor return air temperature sensor, and a first indoor fan 303A.

[0102] For another example, the second indoor unit 300B comprises a second indoor heat exchanger 301B, a second indoor expansion valve 302B, and a second indoor refrigerant leakage detection device.

[0103] ​In some embodiments, the second indoor unit 300B further comprises a second indoor liquid pipe temperature sensor (not shown in the figure), a second indoor return air temperature sensor (not shown in the figure), and a second indoor fan 303B. The second indoor liquid pipe temperature sensor is configured to detect the refrigerant temperature of the indoor unit pipe; and the second indoor return air temperature sensor is configured to detect the return air temperature of the indoor unit.

[0104] The functions and settings of the various components of the indoor unit are described in detail below.

[0105] In some embodiments, the first indoor heat exchanger 301A is configured to exchange heat between the refrigerant flowing in the heat transfer pipe of the first indoor heat exchanger 301A and the indoor air.

[0106] In some embodiments, the first indoor expansion valve 302A is configured between the first indoor heat exchanger 301A and the refrigerant recovery device 400, and has the function of expanding and reducing the pressure of the refrigerant flowing through the first indoor expansion valve 302A, and can be used to adjust the supply amount of the refrigerant in the pipe.

[0107] Optionally, the multi-split air conditioning system can be provided with a plurality of first indoor expansion valves 302A, such as a plurality of electronic expansion valves. If the opening degree of the first indoor expansion valve 302A is reduced, the flow path resistance of the refrigerant passing through the first indoor expansion valve 302A increases. If the opening degree of the first indoor expansion valve 302A is increased, the flow path resistance of the refrigerant passing through the first indoor expansion valve 302A decreases. In this way, even if the state of other devices in the circuit does not change, when the opening degree of the first indoor expansion valve 302A changes, the flow rate of the refrigerant flowing to the first indoor heat exchanger 301A or the outdoor heat exchanger 203 will also change. It should be noted that, FIG. 1 The number of indoor expansion valves and the number of outdoor expansion valves 204 shown are only examples, and the present application does not make specific limitations thereto.

[0108] In some embodiments, the first indoor fan 303A generates an air flow of the indoor air passing through the first indoor heat exchanger 301A to facilitate heat exchange between the refrigerant flowing in the heat transfer pipe of the first indoor heat exchanger 301A and the indoor air.

[0109] In some embodiments, the first indoor unit 300A further comprises an indoor fan motor (not shown in the figure) connected with the indoor fan, configured to drive or change the rotation speed of the indoor fan.

[0110] In some embodiments, the first indoor unit 300A further comprises a plurality of capillary tubes (not shown in the figure) configured to reduce the pressure of the refrigerant in the pipe, and to reduce the pressure of the high-pressure refrigerant delivered by the condenser and deliver it to the evaporator.

[0111] In some embodiments, the first indoor unit 300A further comprises a humidity sensor (not shown in the figure) configured to detect the relative humidity of the indoor air.

[0112] In some embodiments, the first indoor unit 300A further comprises a dew point meter (not shown in the figure) for detecting the ambient dew point temperature near the indoor heat exchanger.

[0113] In some embodiments, the first indoor unit 300A further comprises a display (not shown in the figure). The display is electrically connected to the controller. Optionally, the display is used to display the control panel of the multi-split air conditioning system. For example, the display can be used to display the indoor temperature or the current operation mode. Optionally, the display is connected to the controller, and the user can perform operations on the control panel and set programs through the display. Optionally, the display further comprises a pressure sensor or a temperature sensor, and the display can transmit user instructions to the controller according to user gestures such as pressing a button, etc., to realize the human-computer interaction function. Optionally, the display can be a liquid crystal display, an organic light-emitting diode (OLED) display. The specific type, size and resolution of the display are not limited, and those skilled in the art can understand that the display can be changed in performance and configuration as needed.

[0114] It should be noted that the number of indoor units described above is only an example, and the number of indoor units of the multi-split air conditioning system shown in the present application can be two or more, which is not limited by the present application.

[0115] Refrigerant recovery device 400

[0116] As shown in FIG. 1 The refrigerant recovery device 400 comprises a first electromagnetic valve 401, a second electromagnetic valve 402, a third electromagnetic valve 403, a first expansion valve 411 and a liquid storage tank 404. The first opening of the liquid storage tank 404 is connected to the outdoor expansion valve through the first electromagnetic valve 401, the second opening of the liquid storage tank 404 is connected to the indoor expansion valve through the second electromagnetic valve 402, the third opening of the liquid storage tank 404 is communicated with the first pipeline through the first expansion valve 411, and the third opening of the liquid storage tank 404 is arranged at the bottom of the liquid storage tank 404; the first end of the third electromagnetic valve 403 is connected to the outdoor expansion valve, and the second end of the third electromagnetic valve 403 is connected to the indoor expansion valve. In some embodiments, the refrigerant recovery device 400 further comprises a fourth electromagnetic valve 405, which is arranged on the first pipeline, the first end of the fourth electromagnetic valve 405 is connected to the four-way valve, and the second end of the fourth electromagnetic valve 405 is connected to the indoor heat exchanger.

[0117] In some embodiments, the refrigerant recovery device 400 further comprises a fifth solenoid valve 406, which is arranged on the first pipeline, the first end of the fifth solenoid valve 406 is connected with the second end of the fourth solenoid valve 405, and the second end of the fifth solenoid valve 406 is connected with the indoor heat exchanger.

[0118] In combination FIG. 1 As shown in FIG. 2 and FIG. 3 , in some embodiments, the refrigerant recovery device 400 further comprises a second expansion valve 412. As shown in FIG. 2 , the first end of the second expansion valve 412 is connected with the fourth opening of the liquid accumulator 404, and the second end of the second expansion valve 412 is communicated with the second pipeline, which is the pipeline between the fourth solenoid valve 405 and the fifth solenoid valve 406. For example, the second pipeline is the pipeline (16) as shown in FIG. 3 . As shown in FIG. 3 , the first end of the second expansion valve 412 is communicated with the third pipeline, and the second end of the second expansion valve 412 is communicated with the second pipeline, and the third pipeline is the pipeline between the first solenoid valve 401 and the first opening of the liquid accumulator 404.

[0119] The above-mentioned second expansion valve can have two arrangement modes as shown in FIG. 2 and FIG. 3 , (1) the first end of the second expansion valve 412 is connected with the second end of the fourth solenoid valve 405 through a pipeline, and the second end of the second expansion valve 412 is connected with the second end of the first solenoid valve 401 through a pipeline. (2) the first end of the second expansion valve 412 is connected with the second end of the fourth solenoid valve 405 through a pipeline, and the second end of the second expansion valve 412 is connected with the fourth opening of the liquid accumulator 404 through a pipeline.

[0120] Based on this, during the refrigerant recovery process, the amount of refrigerant circulating in the multi-split air conditioning system is getting smaller and smaller, and the low pressure of the multi-split air conditioning system is getting closer to the preset pressure range (usually referring to the atmospheric pressure of the environment where the multi-split air conditioning system is located). In this case, the discharge temperature of the compressor 201 will be higher and higher, which will affect the reliability of the compressor 201. Based on this, the second expansion valve 412 is added between the first solenoid valve 401 and the fourth solenoid valve 405, or the second expansion valve 412 is added between the fourth solenoid valve 405 and the liquid accumulator 404. During the refrigerant recovery process, the second expansion valve 412 is opened to bypass a part of the refrigerant to the compressor 201, which is used to reduce the discharge temperature of the compressor 201, thereby reducing the temperature of the compressor 201, to ensure the reliability of the compressor 201 during the refrigerant recovery process.

[0121] In addition, during the refrigerant recovery process, the refrigerant entering the liquid storage tank 404 can be in a gaseous and liquid two-phase state, and in the case of two-phase refrigerant entering the liquid storage tank 404, the average density of the two-phase refrigerant is small, so the amount of refrigerant stored in the liquid storage tank 404 will be reduced, thereby affecting the effect of refrigerant recovery. Therefore, during the refrigerant recovery process, the second expansion valve 412 is opened to bypass the gaseous refrigerant to improve the effect of refrigerant recovery.

[0122] It should be noted that the above-mentioned second expansion valve 412 setting mode (1) is suitable for the first refrigerant recovery mode. The above-mentioned second expansion valve 412 setting mode (2) is suitable for both the first refrigerant recovery mode and the second refrigerant recovery mode. Of course, the two modes can also be used in combination, and the specific opening is based on the specific situation. The present application does not specifically limit the setting mode of the second expansion valve 412.

[0123] In addition, the above-mentioned FIG. 2 or FIG. 3 The setting mode of the second expansion valve 412 can be used to improve the refrigerant recovery device 400 in FIG. 4 and FIG. 5 .

[0124] In combination with FIG. 1 , as shown in FIG. 4 , in some embodiments, the refrigerant recovery device 400 further comprises a first subcooling heat exchanger 413. The first subcooling heat exchanger 413 comprises a first passage 416 and a second passage 417; the third opening of the liquid storage tank 404 is in communication with the first pipeline through the first expansion valve 411 and the first passage 416 of the first subcooling heat exchanger 413 in turn; the first end of the third solenoid valve 403 is connected with the outdoor expansion valve through the second passage 417 of the first subcooling heat exchanger 413.

[0125] In combination with FIG. 1 , as shown in FIG. 4 , in some embodiments, the refrigerant recovery device 400 further comprises a first temperature sensor (not shown in the figure). For example, the first temperature sensor is arranged on the pipeline (22) as shown in FIG. 4. The first temperature sensor is used to detect the temperature value of the refrigerant flowing out of the first passage 416 of the first subcooling heat exchanger 413.

[0126] The first outdoor pressure sensor The first outdoor pressure sensor The first outdoor pressure sensor The first outdoor pressure sensor In combination with FIG. 1 , as shown in FIG. 5As shown, in some embodiments, the refrigerant recovery device 400 further includes a throttling device 414 and a second subcooling heat exchanger 415. The second subcooling heat exchanger includes a third channel 418 and a fourth channel 419. The third opening of the liquid storage tank 404 is further connected to the first pipeline via the throttling device 414 and the third channel 418 of the second subcooling heat exchanger 415 in sequence. The second end of the third solenoid valve 403 is connected to the indoor expansion valve via the fourth channel 419 of the second subcooling heat exchanger 415.

[0127] Combine FIG. 1 ,like FIG. 5 As shown, in some embodiments, the refrigerant recovery device 400 further includes a second temperature sensor (not shown in the figure, the second temperature sensor can be located at point c), which is used to detect the temperature of the refrigerant flowing out of the third channel of the second subcooling heat exchanger. First outdoor pressure sensor First outdoor pressure sensor The functions and settings of the various components of the refrigerant recovery device 400 are described in detail below.

[0128] The liquid storage tank 404 is used to store the refrigerant recovered by the multi-split air-conditioning system in the refrigerant recovery mode (ie, the first refrigerant recovery mode and the second refrigerant recovery mode); and to release the recovered refrigerant.

[0129] Based on the above embodiment, FIG. 4 The first subcooling heat exchanger 413 in the multi-connected air conditioning system is used. The refrigerant recovered in the refrigerant recovery device flows through the first channel 416 of the first subcooling heat exchanger 413. During the operation of the multi-connected air conditioning system, the refrigerant flows through the second channel 417 of the first subcooling heat exchanger 413. The second channel 417 cools the refrigerant flowing through the second channel 417 to release the corresponding heat. The first channel 416 uses the heat released by the second channel 417 to heat the recovered refrigerant flowing through the first channel 416, so that the liquid refrigerant in the two-phase (gaseous and liquid) recovered refrigerant is converted into a gaseous refrigerant, reducing the content of the liquid refrigerant in the refrigerant released by the refrigerant recovery device and increasing the content of the gaseous refrigerant in the released recovered refrigerant to ensure the use efficiency of the recovered refrigerant.

[0130] It should be noted that, based on the first supercooling heat exchanger 413, on the one hand, in the process of releasing the recovered refrigerant in the multi-split air conditioning system in the refrigeration mode, the refrigerant recovery device releases the recovered refrigerant to the compressor of the outdoor unit 200, and the content of the liquid refrigerant in the refrigerant released by the refrigerant recovery device is reduced, which reduces the liquid return of the compressor and improves the service life of the compressor. On the other hand, in the process of releasing the recovered refrigerant in the multi-split air conditioning system in the heating mode, the refrigerant recovery device 400 releases the recovered refrigerant to the indoor heat exchanger of the indoor unit, and the content of the gaseous refrigerant in the released recovered refrigerant is increased, which increases the amount of refrigerant entering the indoor heat exchanger for recovery and improves the utilization rate of the recovered refrigerant.

[0131] Based on the first temperature sensor, the opening of the first expansion valve can be reasonably controlled. For example, the following steps S11 to S13 are performed. FIG. 6

[0132] In step S11, when the multi-split air conditioning system operates in the refrigerant release mode, the first temperature value detected by the first temperature sensor and the pressure value detected by the first outdoor pressure sensor are obtained.

[0133] In step S12, if the difference between the first temperature value and the second temperature value is greater than or equal to the first preset temperature value, the opening of the first expansion valve is increased.

[0134] The second temperature value is the saturation temperature value corresponding to the pressure value detected by the first outdoor pressure sensor.

[0135] In step S13, if the difference between the first temperature value and the second temperature value is greater than the first preset temperature value, the opening of the first expansion valve is reduced.

[0136] In this example, by comparing the first temperature value of the refrigerant flowing out of the first channel of the first supercooling heat exchanger with the saturation temperature (i.e., the second temperature value) of the refrigerant at the inlet of the gas-liquid separator corresponding to the pressure value, the temperature difference between the first temperature value and the saturation temperature value is obtained. Based on the size relationship between the temperature difference and the first preset temperature value, the opening of the first expansion valve is controlled to ensure that the opening of the first expansion valve is within a reasonable range, so as to ensure that the amount of refrigerant released by the refrigerant recovery device is within a reasonable range. On the one hand, it avoids that the amount of refrigerant released by the refrigerant recovery device is too much, so that the amount of refrigerant in the entire multi-split air conditioning system pipeline is too much, which leads to that the multi-split air conditioning system cannot handle the refrigerant in time; on the other hand, it avoids that the amount of refrigerant released by the refrigerant recovery device is too small, so that the amount of refrigerant in the entire multi-split air conditioning system pipeline is too small, which reduces the working efficiency of the multi-split air conditioning system, such as reducing the refrigeration speed or the heating speed. Based on the above FIG. 5 ​The throttling device 414 and the second cold heat exchanger 415 are shown. The refrigerant recovered in the refrigerant recovery device is throttled by the throttling device 414 and then flows through the third passage 418 of the second supercooling heat exchanger 415. The multi-split air conditioning system flows through the fourth passage 419 of the second cold heat exchanger 415 during operation. The fourth passage cools the refrigerant flowing through the fourth passage 419 to release corresponding heat. The third passage 418 uses the heat released by the fourth passage 419 to heat the recovered refrigerant flowing through the third passage 418, so that the liquid refrigerant in the recovered refrigerant of two-phase state (gas and liquid) is converted into gaseous refrigerant, reducing the content of liquid refrigerant in the refrigerant released by the refrigerant recovery device, and increasing the content of gaseous refrigerant in the recovered refrigerant released, to ensure the use efficiency of the recovered refrigerant.

[0137] Based on the second temperature sensor in the above embodiment, the refrigerant release process in the refrigerant recovery device 400 can be reasonably controlled.

[0138] For example, the following process FIG. 7 Steps S21 to S23.

[0139] Step S21, when the multi-split air conditioning system operates in the refrigerant release mode, the third temperature value detected by the second temperature sensor and the pressure value detected by the first outdoor pressure sensor are obtained.

[0140] Step S22, if the difference between the third temperature value and the second temperature value is greater than or equal to the second preset temperature value, the refrigerant release mode is ended.

[0141] Wherein, the second temperature value is the saturation temperature value corresponding to the pressure value detected by the first outdoor pressure sensor.

[0142] Step S23, if the difference between the third temperature value and the second temperature value is less than the second preset temperature value, the refrigerant release mode is continued.

[0143] It should be noted that the above-mentioned second preset temperature value is a very small value.

[0144] In addition, the refrigerant released from the liquid storage tank flows through FIG. 5 The refrigerant temperatures at points a and b are the same, and the refrigerant temperatures at points b and c vary due to the change in the amount of refrigerant in the liquid storage tank. Specifically, when there is refrigerant in the liquid storage tank, the refrigerant temperatures at points b and c are equal or the refrigerant temperature at point b is not much different from the refrigerant temperature at point c; when there is no refrigerant release in the liquid storage tank, the refrigerant temperature at point c is greater than the refrigerant temperature at point b.

[0145] In this example, the temperature difference between the first temperature value of the refrigerant flowing out of the third channel 418 of the second subcooling heat exchanger 415 and the second temperature value corresponding to the pressure value of the refrigerant at the gas-liquid separator inlet, i.e. the saturation temperature, is obtained. Based on the size relationship between the temperature difference and the second preset temperature value, the release process of the refrigerant recovery device is reasonably controlled to ensure that the refrigerant recovery device 400 can only release refrigerant when there is sufficient refrigerant, avoiding the situation that the refrigerant recovery device still executes the refrigerant release mode when there is no refrigerant in the refrigerant recovery device, so that the amount of refrigerant in the multi-split air conditioning system is abnormally small, thereby reducing the working efficiency of the multi-split air conditioning system.

[0146] The fourth electromagnetic valve 405 in the above FIGS. 1 to 5 is used to control whether the refrigerant can flow through the first pipeline connected between the indoor unit 300 and the four-way valve 202 of the outdoor unit 200.

[0147] For example, when the multi-split air conditioning system is in any one of the cooling mode, the heating mode, the first refrigerant recovery mode, the second refrigerant recovery mode or the refrigerant release mode, the fourth electromagnetic valve is controlled to be in an open state to ensure that the refrigerant can circulate and flow through the corresponding pipeline.

[0148] The fifth electromagnetic valve in the above FIGS. 1 to 5 is also used to control whether the refrigerant can flow through the first pipeline connected between the indoor unit 300 and the four-way valve 202 of the outdoor unit 200.

[0149] It should be noted that the independence of the refrigerant recovery device and the outdoor unit 200 and the indoor unit 300 can be ensured by closing the first electromagnetic valve 401, the second electromagnetic valve 402, the third electromagnetic valve 403, the fourth electromagnetic valve 405 and the fifth electromagnetic valve 406.

[0150] For example, when the multi-split air conditioning system is in any one of the cooling mode, the heating mode, the first refrigerant recovery mode, the second refrigerant recovery mode or the refrigerant release mode, the fifth electromagnetic valve is controlled to be in an open state to ensure that the refrigerant can circulate and flow through the corresponding pipeline.

[0151] Based on the above embodiments, as FIGS. 1 to 5As shown, the refrigerant recovery device 400 further comprises: a first stop valve 407, which is arranged on the pipeline between the four-way valve 202 and the fourth electromagnetic valve 405, the first end of the first stop valve 407 is connected with the four-way valve 202 through the pipeline, and the second end of the first stop valve 407 is connected with the first end of the fourth electromagnetic valve 405 through the pipeline; a second stop valve 408, which is arranged on the pipeline between the fourth electromagnetic valve 405 and the indoor heat exchanger, the first end of the second stop valve 408 is connected with the second end of the fourth electromagnetic valve 405 through the pipeline, and the second end of the second stop valve 408 is connected with the indoor heat exchanger in each indoor unit through the pipeline; a third stop valve 409, which is arranged on the pipeline between the outdoor expansion valve 204 and the first electromagnetic valve 401, the first end of the third stop valve 409 is connected with the outdoor expansion valve 204 through the pipeline, and the second end of the third stop valve 409 is connected with the first end of the first electromagnetic valve 401 through the pipeline; and a fourth stop valve 410, which is arranged on the pipeline between the second electromagnetic valve 402 and the indoor heat exchanger, the first end of the fourth stop valve 410 is connected with the second end of the second electromagnetic valve 402 through the pipeline, and the second end of the fourth stop valve 410 is connected with the indoor expansion valve in each indoor unit through the pipeline.

[0152] In this embodiment, during the operation of the multi-split air conditioning system in the first refrigerant recovery mode or the second refrigerant recovery mode, the first stop valve 407, the second stop valve 408, the third stop valve 409 and the fourth stop valve 410 are in the open state. After the first refrigerant recovery mode or the second refrigerant recovery mode is completed, the first electromagnetic valve 401, the second electromagnetic valve 402 and the third electromagnetic valve 403 are in the closed state, and at the same time, the first stop valve 407, the second stop valve 408, the third stop valve 409 and the fourth stop valve 410 are in the closed state, so as to better prevent the circulation of the refrigerant in the pipelines corresponding to the stop valves.

[0153] It should be noted that the number of stop valves arranged in the multi-split air conditioning system can be determined according to specific requirements. For example, two stop valves can be arranged at both ends of the indoor unit group 300, i.e., one stop valve is arranged at the end of the indoor unit group 300 connected with the four-way valve 202, i.e., the stop valve is arranged on the pipeline (14) as shown in FIG. 8, such as the eighth stop valve 305 in FIG. 8; and the other stop valve is arranged at the end of the indoor unit group 300 connected with the refrigerant recovery device 400, i.e., the stop valve is arranged on the pipeline (9) as shown in FIG. 8, such as the eighth stop valve 304 in FIG. 8. FIGS. 2 to 7 FIG. 14 FIGS. 2 to 5 FIG. 14

[0154] ​​​​In some embodiments, the multi-split air conditioning system has at least one or more of the following operating modes: cooling mode, heating mode, first refrigerant recovery mode, second refrigerant recovery mode, and refrigerant release mode. Each of these operating modes is described in detail below.

[0155] 1. Cooling mode

[0156] When the multi-split air-conditioning system is in cooling mode, the outdoor heat exchanger 203 works as a condenser, the indoor heat exchanger works as an evaporator, the first solenoid valve 401 is in a closed state, the second solenoid valve 402 is in a closed state, and the third solenoid valve 403 is in an open state; the first expansion valve 411 is in a closed state.

[0157] In some embodiments, the four-way valve 202 may be a four-way reversing valve.

[0158] Taking the first indoor unit 300A and the second indoor unit 300B as an example, both of which require cooling, the operation cycle of the cooling mode of the air-conditioning system is described in detail. FIG. 1 ,like FIG. 8 As shown, the D port of the four-way reversing valve is connected to the C port, and the E port is connected to the S port; the first solenoid valve 401, the second solenoid valve 402 and the first expansion valve 411 are closed, the third solenoid valve 403 and the fourth solenoid valve 405 are opened, and the other solenoid valves, indoor expansion valve, outdoor expansion valve, expansion valve and stop valve are all opened.

[0159] The refrigerant circuit flowing through the first indoor unit 300A in the indoor unit group 300 is: (1)→(2)→(3)→(4)→(5)→(6)→(7)→(8)→(9)→(10)→(12)→(14)→(15)→(16)→(17)→(18)→(19)→(1).

[0160] The refrigerant circuit flowing through the second indoor unit 300B in the indoor unit group 300 is: (1)→(2)→(3)→(4)→(5)→(6)→(7)→(8)→(9)→(11)→(13)→(14)→(15)→(16)→(17)→(18)→(19)→(1).

[0161] It should be noted that (14) → (15) → (16) → (17) is only an example. The (14) → (15) → (16) → (17) shown in this application can be replaced by one or more pipelines. For example, it can be replaced by pipeline (16), that is, there is only the fourth solenoid valve 405 or the fourth solenoid valve 405 and the first stop valve 407 on the pipeline. The number of solenoid valves and the number of stop valves provided on this section of pipeline are set according to specific needs.

[0162] Specifically, the high-temperature, high-pressure gaseous refrigerant discharged from compressor 201 enters oil separator 206. The refrigerant entering oil separator 206 is divided into two parts. One part enters the inlet of gas-liquid separator 205 through oil return capillary tube 207. The other part of the high-temperature, high-pressure gaseous refrigerant exiting oil separator 206 passes through a one-way valve and a four-way valve 202 and enters outdoor heat exchanger 203. This high-temperature, high-pressure gaseous refrigerant is condensed in outdoor heat exchanger 203 into medium-temperature, high-pressure liquid refrigerant. Furthermore, the medium-temperature and high-pressure liquid refrigerant passes through the outdoor electronic expansion valve and the third solenoid valve 403 of the refrigerant recovery device 400 in sequence, and is then divided into two parts. One part flows into the first indoor solenoid valve of the first indoor unit 300A to form a low-temperature and low-pressure liquid refrigerant, and the low-temperature and low-pressure liquid refrigerant then flows into the first indoor heat exchanger 301A, and evaporates into a low-temperature and low-pressure gaseous refrigerant through the first indoor heat exchanger 301A; the other part flows into the second indoor solenoid valve of the second indoor unit 300B to form a low-temperature and low-pressure liquid refrigerant, and the low-temperature and low-pressure liquid refrigerant then flows into the second indoor heat exchanger 301B, and evaporates into a low-temperature and low-pressure gaseous refrigerant through the second indoor heat exchanger 301B. The low-temperature, low-pressure gaseous refrigerant evaporated through the first indoor heat exchanger 301A and the second indoor heat exchanger 301B and merged, and entered the four-way reversing valve through the fourth solenoid valve 405, and the low-temperature, low-pressure gaseous refrigerant entered the gas-liquid separator 205; the low-temperature, low-pressure gaseous refrigerant flowing out of the gas-liquid separator 205 entered the suction port of the compressor 201, and the low-temperature, low-pressure gaseous refrigerant was compressed into high-temperature, high-pressure gaseous refrigerant by the compressor 201, and discharged from the compressor 201, thereby completing the refrigeration operation of the air-conditioning system.

[0163] 2. Heating mode

[0164] When the multi-split air-conditioning system is in heating mode, the outdoor heat exchanger 203 works as an evaporator, the indoor heat exchanger works as a condenser, the first solenoid valve 401 is in a closed state, the second solenoid valve 402 is in a closed state, the third solenoid valve 403 is in an open state, and the first expansion valve 411 is in an open state.

[0165] Taking the first indoor unit 300A and the second indoor unit 300B as an example, both of which are indoor units that need to heat, the operation cycle of the heating mode of the air-conditioning system is described in detail. FIG. 1 ,like FIG. 9 As shown, the S port of the four-way reversing valve is connected to the C port, and the E port is connected to the D port; the first solenoid valve 401, the second solenoid valve 402 and the first expansion valve 411 are closed, the third solenoid valve 403 and the fourth solenoid valve 405 are opened, and the other solenoid valves, expansion valves and stop valves are all opened.

[0166] The refrigerant circuit flowing through the first indoor unit 300A in the indoor unit group 300 is: (1)→(2)→(18)→(17)→(16)→(15)→(14)→(12)→(10)→(9)→(8)→(7)→(6)→(5)→(4)→(3)→(19)→(1).

[0167] The refrigerant circuit flowing through the second indoor unit 300B in the indoor unit group 300 is: (1)→(2)→(18)→(17)→(16)→(15)→(14)→(13)→(11)→(9)→(8)→(7)→(6)→(5)→(4)→(3)→(19)→(1).

[0168] It should be noted that (14)→(15)→(16)→(17) is only an example, and the (14)→(15)→(16)→(17) shown in the present application can be replaced by one pipe or multiple pipes. For example, replace it with pipe (16), that is, only the fourth electromagnetic valve 405 or the fourth electromagnetic valve 405 and the first stop valve 407 on the pipe. The number of electromagnetic valves and stop valves provided on this section of pipe is set according to specific needs.

[0169] Specifically, the high-temperature and high-pressure gaseous refrigerant discharged by the compressor 201 enters the oil separator 206. The refrigerant entering the oil separator 206 is divided into two parts. One part enters the inlet of the gas-liquid separator 205 through the oil return capillary tube 207; the other part of the high-temperature and high-pressure gaseous refrigerant discharged by the oil separator 206 is sequentially divided into the first indoor heat exchanger 301A of the first indoor unit 300A and the second indoor heat exchanger 301B of the second indoor unit 300B through the one-way valve, the four-way valve 202 and the fourth electromagnetic valve 405. The first indoor heat exchanger 301A and the second indoor heat exchanger 301B respectively condense the entering high-temperature and high-pressure gaseous refrigerant into medium-temperature and high-pressure liquid refrigerant. The condensed medium-temperature and high-pressure liquid refrigerant respectively passes through the first indoor expansion valve 302A and the second indoor expansion valve 302B and then converges. The converged refrigerant sequentially passes through the third electromagnetic valve 403 and the outdoor expansion valve 204 and is throttled to form low-temperature and low-pressure liquid refrigerant. The low-temperature and low-pressure liquid refrigerant evaporates into low-temperature and low-pressure gaseous refrigerant through the outdoor heat exchanger 203, and the low-temperature and low-pressure gaseous refrigerant enters the gas-liquid separator 205; the low-temperature and low-pressure gaseous refrigerant flowing out of the gas-liquid separator 205 enters the suction port of the compressor 201; the low-temperature and low-pressure gaseous refrigerant is compressed into high-temperature and high-pressure gaseous refrigerant by the compressor 201, and is discharged from the compressor 201, thereby completing the operation of the air conditioning system in the heating mode.

[0170] 3. First refrigerant recovery mode

[0171] When the multi-split air conditioning system is in the first refrigerant recovery mode, the outdoor heat exchanger 203 works as a condenser, the indoor heat exchanger works as an evaporator, the first electromagnetic valve 401 is in an open state, the second electromagnetic valve 402 is in a closed state, the third electromagnetic valve 403 is in a closed state, and the first expansion valve 411 is in a closed state.

[0172] As a possible implementation, when the indoor unit is detected to have refrigerant leakage, whether the multi-split air conditioning system is in a cooling mode or a heating mode, the multi-split air conditioning system is switched to the cooling mode operation while the first electromagnetic valve 401 is in an open state, the second electromagnetic valve 402 is in a closed state, and the third electromagnetic valve 403 is in a closed state.

[0173] Taking the first indoor unit 300A having refrigerant leakage and the second indoor unit 300B not having refrigerant leakage as an example, the operation cycle of the first refrigerant recovery mode of the air conditioning system is described in detail. FIG. 2 As shown in FIG. 6, the D port of the four-way reversing valve is connected with the C port, and the E port is connected with the S port; the first indoor expansion valve 302A is closed, the second electromagnetic valve 402 is closed, and the third electromagnetic valve 403 is closed, the first electromagnetic valve 401 and the fourth electromagnetic valve 405 are both open, and other electromagnetic valves, other expansion valves, and stop valves are all open. FIG. 10

[0174] The refrigerant flowing through the outdoor unit 200 flows in the following direction: (1)→(2)→(3)→(4)→(5)→(6)→(20).

[0175] The refrigerant flowing through the second indoor unit 300B in the indoor unit group 300 flows in the following direction: (8)→(9)→(11)→(13)→(14)→(15)→(16)→(17)→(18)→(19)→(1)→(2)→(3)→(4)→(5)→(6)→(20).

[0176] It should be noted that the refrigerant in the pipeline (8) and the pipeline (9) can run through the second indoor unit 300B (the indoor unit not having refrigerant leakage) to the compressor 201, be discharged by the compressor 201, or be recovered to the refrigerant recovery device 400.

[0177] ​Specifically, the high-temperature and high-pressure gaseous refrigerant discharged by the compressor 201 enters the oil separator 206, and the refrigerant entering the oil separator 206 is divided into two parts. One part enters the inlet of the gas-liquid separator 205 through the oil return capillary tube 207; the other part of the high-temperature and high-pressure gaseous refrigerant discharged by the oil separator 206 enters the outdoor heat exchanger 203 through the one-way valve and the four-way valve 202. The high-temperature and high-pressure gaseous refrigerant condenses into medium-temperature and high-pressure liquid refrigerant in the outdoor heat exchanger 203. Further, the medium-temperature and high-pressure liquid refrigerant successively passes through the outdoor electronic expansion valve and the first solenoid valve 401 of the refrigerant recovery device 400, and the medium-temperature and high-pressure liquid refrigerant is stored in the liquid storage tank 404. The low-temperature and low-pressure liquid refrigerant in the pipeline (8) and the pipeline (9) flows into the second indoor solenoid valve of the second indoor unit 300B to form low-temperature and low-pressure liquid refrigerant, and then the low-temperature and low-pressure liquid refrigerant flows into the second indoor heat exchanger 301B and evaporates into low-temperature and low-pressure gaseous refrigerant through the second indoor heat exchanger 301B. The low-temperature and low-pressure gaseous refrigerant enters the four-way valve through the fourth solenoid valve 405, and the low-temperature and low-pressure gaseous refrigerant enters the gas-liquid separator 205; the low-temperature and low-pressure gaseous refrigerant flowing out of the gas-liquid separator 205 enters the suction inlet of the compressor 201, and the low-temperature and low-pressure gaseous refrigerant is compressed into high-temperature and high-pressure gaseous refrigerant by the compressor 201, and is discharged from the compressor 201, thereby completing the operation of the first refrigerant recovery mode of the air conditioning system.

[0178] Optionally, during the operation of the first refrigerant recovery mode, the indoor expansion valve corresponding to the indoor unit where refrigerant leakage occurs is closed, and the opening degree of the indoor expansion valve corresponding to the indoor unit where refrigerant leakage does not occur is opened to the maximum opening degree.

[0179] For example, when the first indoor unit 300A leaks refrigerant and the second indoor unit 300B does not leak refrigerant, the first indoor expansion valve 302A is closed, and the opening degree of the second indoor expansion valve 302B is opened to the maximum value.

[0180] 4. Second refrigerant recovery mode

[0181] When the multi-split air conditioning system is in the second refrigerant recovery mode, the outdoor heat exchanger 203 works as an evaporator, the indoor heat exchanger works as a condenser, the first solenoid valve 401 is in a closed state, the second solenoid valve 402 is in an open state, and the third solenoid valve 403 is in a closed state.

[0182] Taking the outdoor unit 200 as an example, as a possible implementation, when it is detected that the outdoor unit 200 leaks refrigerant, whether the multi-split air conditioning system is in a cooling mode or a heating mode, the multi-split air conditioning system is switched to operate in the heating mode while the first solenoid valve 401 is in a closed state, the second solenoid valve 402 is in an open state, and the third solenoid valve 403 is in a closed state.

[0183] The operation cycle of the second refrigerant recovery mode of the air conditioning system is described in detail. FIG. 1 ,like FIG. 11 As shown, the S port of the four-way reversing valve is connected to the C port, and the E port is connected to the D port; the first solenoid valve 401, the third solenoid valve 403 and the first expansion valve 411 are closed, the second solenoid valve 402 and the fourth solenoid valve 405 are opened, and the other solenoid valves, expansion valves and stop valves are all opened.

[0184] The refrigerant flow direction through the first indoor unit 300A in the indoor unit group 300 is: (1)→(2)→(18)→(17)→(16)→(15)→(14)→(12)→(10)→(9)→(21).

[0185] The refrigerant flow direction through the second indoor unit 300B in the indoor unit group 300 is: (1)→(2)→(18)→(17)→(16)→(15)→(14)→(13)→(11)→(9)→(21).

[0186] The refrigerant flow direction of the outdoor unit 200 is: (3) → (19) → (1).

[0187] Specifically, the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 201 enters the oil separator 206. The refrigerant entering the oil separator 206 is divided into two parts. One part passes through the oil return capillary tube 207 and enters the inlet of the gas-liquid separator 205. The other part of the high-temperature, high-pressure gaseous refrigerant exiting the oil separator 206 is diverted through the one-way valve, the four-way valve 202, and the fourth solenoid valve 405, entering the first indoor heat exchanger 301A of the first indoor unit 300A and the second indoor heat exchanger 301B of the second indoor unit 300B. The first indoor heat exchanger 301A and the second indoor heat exchanger 301B respectively condense the incoming high-temperature, high-pressure gaseous refrigerant into medium-temperature, high-pressure liquid refrigerant. The condensed medium-temperature, high-pressure liquid refrigerant passes through the first indoor expansion valve 302A and the second indoor expansion valve 302B, respectively, before being combined. The combined refrigerant passes through the second solenoid valve 402 and is stored in the liquid storage tank 404. The refrigerant in the outdoor unit 200 evaporates into a low-temperature, low-pressure gaseous refrigerant through the outdoor heat exchanger 203, and the low-temperature, low-pressure gaseous refrigerant enters the gas-liquid separator 205; the low-temperature, low-pressure gaseous refrigerant flowing out of the gas-liquid separator 205 enters the suction port of the compressor 201; the low-temperature, low-pressure gaseous refrigerant is compressed by the compressor 201 into a high-temperature, high-pressure gaseous refrigerant, and is discharged from the compressor 201, thereby completing the operation of the second refrigerant recovery mode of the air-conditioning system.

[0188] 5. Refrigerant release mode

[0189] When the multi-split air conditioning system is in the refrigerant release mode, the first electromagnetic valve 401 is in the closed state, the second electromagnetic valve 402 is in the closed state, the third electromagnetic valve 403 is in the open state, and the first expansion valve 411 is in the open state. One of the outdoor heat exchanger 203 and the indoor heat exchanger (such as 301A and 301B) works as an evaporator, and the other works as a condenser.

[0190] Specifically, there are two application scenarios: 1. When the multi-split air conditioning system is in the refrigeration mode and the recovered refrigerant needs to be released, the outdoor heat exchanger works as a condenser, the indoor heat exchanger works as an evaporator, the first electromagnetic valve is in the closed state, the second electromagnetic valve is in the closed state, the third electromagnetic valve is in the open state, and the first expansion valve is in the open state. 2. When the multi-split air conditioning system is in the heating mode and the recovered refrigerant needs to be released, the outdoor heat exchanger works as an evaporator, the indoor heat exchanger works as a condenser, the first electromagnetic valve is in the closed state, the second electromagnetic valve is in the closed state, the third electromagnetic valve is in the open state, and the expansion valve is in the open state.

[0191] In scenario 1, as shown in FIG. 12 , the outdoor heat exchanger 203 works as a condenser, the indoor heat exchanger works as an evaporator, the first electromagnetic valve 401 is in the closed state, the second electromagnetic valve 402 is in the closed state, and the third electromagnetic valve 403 is in the open state. The first expansion valve 411 is in the open state. Taking the first indoor unit 300A and the second indoor unit 300B as examples, the operation cycle of the refrigerant release mode of the air conditioning system is described in detail. FIG. 1 , as shown in FIG. 12 , the D port of the four-way reversing valve is connected with the C port, and the E port is connected with the S port; the first electromagnetic valve 401 and the second electromagnetic valve 402 are closed, the third electromagnetic valve 403, the fourth electromagnetic valve 405, and the first expansion valve 411 are opened, and other electromagnetic valves, indoor expansion valves, outdoor expansion valves, expansion valves, and shut-off valves are opened.

[0192] The refrigerant circuit flowing through the first indoor unit 300A in the indoor unit group 300 is: (1)→(2)→(3)→(4)→(5)→(6)→(7)→(8)→(9)→(10)→(12)→(14)→(15)→(16)→(17)→(18)→(19)→(1).

[0193] The refrigerant circuit flowing through the second indoor unit 300B in the indoor unit group 300 is: (1)→(2)→(3)→(4)→(5)→(6)→(7)→(8)→(9)→(11)→(13)→(14)→(15)→(16)→(17)→(18)→(19)→(1).

[0194] The refrigerant branch flowing through the outdoor unit is: (15)→(16)→(17)→(18)→(19)→(1)→(2)→(3)→(4)→(22)→(17)→(18)→(19)→(1)→(2)→(3)→(4).

[0195] It should be noted that (14)→(15)→(16)→(17) is only an example, and the (14)→(15)→(16)→(17) shown in the present application can be replaced by one pipe or multiple pipes. For example, replace it with pipe (16), that is, there is only the fourth electromagnetic valve 405 or the fourth electromagnetic valve 405 and the first stop valve 407 on the pipe. The number of electromagnetic valves and stop valves provided on this section of pipe is set according to specific needs.

[0196] Specifically, the high-temperature and high-pressure gaseous refrigerant discharged by the compressor 201 enters the oil separator 206, and the refrigerant entering the oil separator 206 is divided into two parts. One part enters the inlet of the gas-liquid separator 205 through the oil return capillary tube 207; the other part of the high-temperature and high-pressure gaseous refrigerant discharged by the oil separator 206 passes through the one-way valve and the four-way valve 202 into the outdoor heat exchanger 203. The high-temperature and high-pressure gaseous refrigerant condenses into medium-temperature and high-pressure liquid refrigerant in the outdoor heat exchanger 203. Further, the medium-temperature and high-pressure liquid refrigerant successively passes through the outdoor electronic expansion valve, the third electromagnetic valve 403 of the refrigerant recovery device 400, and is divided into two parts. One part flows into the first indoor electromagnetic valve of the first indoor unit 300A to form low-temperature and low-pressure liquid refrigerant, and then the low-temperature and low-pressure liquid refrigerant flows into the first indoor heat exchanger 301A and evaporates into low-temperature and low-pressure gaseous refrigerant through the first indoor heat exchanger 301A; the other part flows into the second indoor electromagnetic valve of the second indoor unit 300B to form low-temperature and low-pressure liquid refrigerant, and then the low-temperature and low-pressure liquid refrigerant flows into the second indoor heat exchanger 301B and evaporates into low-temperature and low-pressure gaseous refrigerant through the second indoor heat exchanger 301B. The low-temperature and low-pressure gaseous refrigerant evaporated through the first indoor heat exchanger 301A and the second indoor heat exchanger 301B is combined, and the liquid refrigerant stored in the liquid accumulator 404 is throttled into low-temperature and low-pressure refrigerant through the first expansion valve 411. The low-temperature and low-pressure refrigerant is combined with the refrigerant flowing out of each indoor unit in the indoor unit group, and then combined again with the low-temperature and low-pressure gaseous refrigerant entering the four-way valve through the fourth electromagnetic valve 405. The low-temperature and low-pressure gaseous refrigerant enters the gas-liquid separator 205; the low-temperature and low-pressure gaseous refrigerant flowing out of the gas-liquid separator 205 enters the suction port of the compressor 201, and the low-temperature and low-pressure gaseous refrigerant is compressed into high-temperature and high-pressure gaseous refrigerant by the compressor 201 and discharged from the compressor 201, thereby completing the refrigeration operation of the air conditioning system.

[0197] In scenario 2, as FIG. 13As shown, the outdoor heat exchanger 203 works as an evaporator, the indoor heat exchanger works as a condenser, the first electromagnetic valve 401 is in a closed state, the second electromagnetic valve 402 is in a closed state, the third electromagnetic valve 403 is in an open state, and the first expansion valve 411 is in an open state.

[0198] Taking the first indoor unit 300A and the second indoor unit 300B as examples, the operation cycle of the refrigerant release mode of the air conditioning system is described in detail. It is combined with FIG. 1 As shown in FIG. 6, the S port and the C port of the four-way reversing valve are connected, the E port and the D port are connected, the first electromagnetic valve 401 and the second electromagnetic valve 402 are closed, the first expansion valve 411 is open, the third electromagnetic valve 403 and the fourth electromagnetic valve 405 are open, and the other electromagnetic valves, expansion valves and stop valves are open. FIG. 13 The refrigerant circuit flowing through the first indoor unit 300A in the indoor unit group 300 is: (1)→(2)→(18)→(17)→(16)→(15)→(14)→(12)→(10)→(9)→(8)→(7)→(6)→(5)→(4)→(3)→(19)→(1) and (22)→(15)→(14)→(12)→(10)→(9)→(8)→(7)→(6)→(5)→(4)→(3)→(19)→(1).

[0199] The refrigerant circuit flowing through the second indoor unit 300B in the indoor unit group 300 is: (1)→(2)→(18)→(17)→(16)→(15)→(14)→(13)→(11)→(9)→(8)→(7)→(6)→(5)→(4)→(3)→(19)→(1) and (22)→(15)→(14)→(13)→(11)→(9)→(8)→(7)→(6)→(5)→(4)→(3)→(19)→(1).

[0200] It should be noted that (14)→(15)→(16)→(17) is only an example, and the (14)→(15)→(16)→(17) shown in the present application can be replaced by one pipe or multiple pipes. For example, replace it with pipe (16), that is, only the fourth electromagnetic valve 405 or the fourth electromagnetic valve 405 and the first stop valve 407 on the pipe. The number of electromagnetic valves and stop valves provided on the pipe is set according to specific needs.

[0201]

[0202] ​Specifically, the high-temperature and high-pressure gaseous refrigerant discharged by the compressor 201 enters the oil separator 206. The refrigerant entering the oil separator 206 is divided into two parts. One part enters the inlet of the gas-liquid separator 205 through the oil return capillary tube 207; the other part of the high-temperature and high-pressure gaseous refrigerant discharged by the oil separator 206 passes through the one-way valve, the four-way valve 202 and the fourth electromagnetic valve 405 in turn. At the same time, the liquid refrigerant stored in the liquid storage tank 404 is throttled into low-temperature and low-pressure refrigerant by the first expansion valve 411. The high-temperature and high-pressure gaseous refrigerant passing through the four-way valve 202 and the fourth electromagnetic valve 405 in turn and the refrigerant throttled into low-temperature and low-pressure refrigerant by the first expansion valve 411 are combined and then divided into the first indoor heat exchanger 301A of the first indoor unit 300A and the second indoor heat exchanger 301B of the second indoor unit 300B. The first indoor heat exchanger 301A and the second indoor heat exchanger 301B condense the entering high-temperature and high-pressure gaseous refrigerant into medium-temperature and high-pressure liquid refrigerant respectively. The condensed medium-temperature and high-pressure liquid refrigerant is combined after passing through the first indoor expansion valve 302A and the second indoor expansion valve 302B respectively. The combined refrigerant is throttled into low-temperature and low-pressure liquid refrigerant after passing through the third electromagnetic valve 403 and the outdoor expansion valve 204 in turn. The low-temperature and low-pressure liquid refrigerant evaporates into low-temperature and low-pressure gaseous refrigerant after passing through the outdoor heat exchanger 203. The low-temperature and low-pressure gaseous refrigerant enters the gas-liquid separator 205; the low-temperature and low-pressure gaseous refrigerant flowing out of the gas-liquid separator 205 enters the suction port of the compressor 201; the low-temperature and low-pressure gaseous refrigerant is compressed into high-temperature and high-pressure gaseous refrigerant by the compressor 201, and is discharged from the compressor 201, thereby completing the heating mode operation of the air conditioning system. It should be noted that the above two scenarios are only examples and are not all scenarios. Other application scenarios can also be combined to adjust the release of refrigerant flow direction, such as changing the refrigeration mode and heating mode in the above scenario 1 and scenario 2 to other working modes such as dehumidification mode, dry mode, etc. When the refrigerant recovery device is detected to have refrigerant, the refrigerant release mode is first started to completely release the refrigerant in the refrigerant recovery device, and then other working modes (such as refrigeration mode, heating mode, dehumidification mode, dry mode) are operated.

[0203] Based on the above five different operating modes, the multi-split air conditioning system can provide the corresponding working mode for different scenes. Specifically, when cooling is needed (e.g., the room temperature is too high), the operating mode of the multi-split air conditioning system is switched to the cooling mode to reduce the indoor environment temperature. When heating is needed (e.g., the room temperature is too low), the operating mode of the multi-split air conditioning system is switched to the heating mode to increase the indoor environment temperature. When the leaked refrigerant of the indoor unit needs to be recovered, the multi-split air conditioning system can be switched to the first refrigerant recovery mode to recover the leaked refrigerant of the indoor unit through the refrigerant recovery device 400. When the leaked refrigerant of the outdoor unit 200 needs to be recovered, the multi-split air conditioning system can be switched to the second refrigerant recovery mode to recover the leaked refrigerant of the outdoor unit 200 through the refrigerant recovery device 400. When the recovered refrigerant in the refrigerant recovery device 400 needs to be utilized, the multi-split air conditioning system can be adjusted to the refrigerant release mode to release the recovered refrigerant into the first pipeline for use of the recovered refrigerant in the cooling operation or the heating operation of the multi-split air conditioning system. In some embodiments, the multi-split air conditioning system 100 further includes a controller (not shown in the figure). FIG. 1

[0204] In some embodiments, the controller refers to a device that can generate operation control signals according to instruction operation codes and timing signals to instruct the multi-split 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.

[0205] Although FIG. 1 not shown, the multi-split air conditioning system can further include a power supply device (such as a battery and a power management chip) for supplying power to each component. The battery can be connected to the controller logic through the power management chip, so as to realize the power consumption management and other functions of the multi-split air conditioning system through the power supply device.

[0206] ​In some embodiments, the controller is electrically connected with the indoor refrigerant leakage detection device in each indoor unit; the controller is configured to: acquire the detection result of each indoor refrigerant leakage detection device, the detection result of one indoor refrigerant leakage detection device being used to indicate whether the indoor unit where the refrigerant leakage detection device is located has refrigerant leakage; determine whether there is an indoor unit having refrigerant leakage in the indoor unit group 300 according to the detection result of each indoor refrigerant leakage detection device; and if so, control the multi-split air conditioning system to run in the first refrigerant recovery mode.

[0207] In this way, the multi-split air conditioning system can determine the indoor unit having refrigerant leakage in the indoor unit group 300 according to the detection result of the indoor refrigerant leakage detection device. In the case that there is an indoor unit having refrigerant leakage in the indoor unit group 300, the multi-split air conditioning system is controlled to switch to the first refrigerant recovery mode for operation, so as to recover the refrigerant leaked from the indoor unit into the refrigerant recovery device 400. On the one hand, this avoids the refrigerant leakage from the indoor unit to the indoor environment, thereby improving the safety of the multi-split air conditioning system; on the other hand, the refrigerant recovery device 400 is used to recover the refrigerant, which greatly reduces the amount of refrigerant discharged from the outdoor unit 200 to the outdoor environment, thereby improving the environmental protection performance of the multi-split air conditioning system.

[0208] In some embodiments, the controller is further configured to: close the indoor expansion valve in the indoor unit having refrigerant leakage when the multi-split air conditioning system runs in the first refrigerant recovery mode.

[0209] In this embodiment, the indoor expansion valve in the indoor unit having refrigerant leakage is closed when the multi-split air conditioning system runs in the first refrigerant recovery mode, so as to prevent the refrigerant from continuously entering the indoor unit having refrigerant leakage, thereby avoiding the refrigerant leaked from the indoor unit having refrigerant leakage to the indoor environment, and further ensuring the safe use of the multi-split air conditioning system by the user.

[0210] Optionally, the opening degree of the indoor expansion valve in the indoor unit not having refrigerant leakage in the indoor unit group 300 is adjusted to the maximum opening degree when the multi-split air conditioning system runs in the first refrigerant recovery mode, so as to make the refrigerant in the pipeline connected with the indoor expansion valve in the indoor unit having refrigerant leakage pass through the indoor unit and the outdoor unit 200 more quickly to be recovered into the refrigerant recovery device 400, thereby improving the recovery speed of the refrigerant leaked from the indoor unit and ensuring the refrigerant recovery efficiency of the multi-split air conditioning system.

[0211] In some embodiments, the controller is further configured to: in the first refrigerant recovery mode, control the fourth electromagnetic valve 405 to be closed when a refrigerant recovery stop condition is met; wherein the refrigerant recovery stop condition includes one or more of the following: the time length for which the multi-split air conditioning system runs in the first refrigerant recovery mode reaches a preset time length; or the pressure of the refrigerant entering the compressor 201 is within a preset pressure range.

[0212] It should be noted that the above-mentioned preset pressure range is determined according to the atmospheric pressure of the outdoor environment.

[0213] Optionally, the pressure of the refrigerant of the compressor 201 is detected by a first outdoor pressure sensor 209 arranged at the suction port of the compressor 201. FIG. 2

[0214] Based on this, by setting the refrigerant recovery stop condition, the timing of ending the refrigerant recovery can be determined, so that the refrigerant is recovered when the amount of refrigerant in the pipeline of the multi-split air conditioning system is in a reasonable range, thereby avoiding the execution of the first refrigerant recovery mode in the case that there is no refrigerant in the pipeline of the multi-split air conditioning system, causing the multi-split air conditioning system to be abnormal or damaged, and thus improving the safety and service life of the multi-split air conditioning system.

[0215] Based on the above embodiment, the refrigerant recovery device 400 is further provided with a fifth electromagnetic valve 406, a first end of the fifth electromagnetic valve 406 is connected to a second end of the fourth electromagnetic valve 405 through a pipeline, and a second end of the fifth electromagnetic valve 406 is connected to the indoor heat exchanger in each indoor unit through a pipeline; when the multi-split air conditioning system is in the refrigeration mode, the heating mode, or the first refrigerant recovery mode, the fifth electromagnetic valve 406 is in an open state.

[0216] Based on the above embodiment, the controller is further configured to: in the first refrigerant recovery mode, when the refrigerant recovery stop condition is met, control the fifth electromagnetic valve 406 to be closed; wherein the refrigerant recovery stop condition includes one or more of the following: the duration of the multi-split air conditioning system operating in the first refrigerant recovery mode has reached a preset duration; or the pressure of the refrigerant entering the compressor 201 is within a preset pressure range.

[0217] In some embodiments, the outdoor unit 200 controller is electrically connected with an outdoor refrigerant leakage detection device of the outdoor unit 200; the controller is configured to: obtain a detection result of the outdoor refrigerant leakage detection device, the detection result of the outdoor refrigerant leakage detection device being used to indicate whether the outdoor unit 200 has leaked refrigerant; if the detection result of the outdoor refrigerant leakage detection device indicates that the outdoor unit 200 has leaked refrigerant, control the multi-split air conditioning system to operate in the second refrigerant recovery mode.

[0218] In this way, the multi-split air conditioning system can determine whether the outdoor unit 200 has leaked refrigerant through the detection result of the outdoor refrigerant leakage detection device. In the case that the outdoor unit 200 has leaked refrigerant, the multi-split air conditioning system is controlled to switch to the second refrigerant recovery mode and operate, and the leaked refrigerant of the outdoor unit 200 is recovered into the refrigerant recovery device 400, so that the refrigerant is recovered by the refrigerant recovery device 400, greatly reducing the amount of refrigerant discharged from the outdoor unit 200 to the outdoor environment, and improving the environmental protection of the multi-split air conditioning system. ​

[0219] In some embodiments, the outdoor expansion valve 204 is controlled to be at a maximum opening value when the multi-split air conditioning system is operating in the second refrigerant recovery mode.

[0220] In this embodiment, the outdoor expansion valve 204 is controlled to be at a maximum opening value when the multi-split air conditioning system is operating in the second refrigerant recovery mode, so that the refrigerant in the pipeline connected to the outdoor expansion valve 204 passes through the outdoor unit 200 and the indoor unit more quickly and is recovered to the refrigerant recovery device 400, thereby improving the recovery speed of the refrigerant leaked from the outdoor unit 200 and ensuring the refrigerant recovery efficiency of the multi-split air conditioning system.

[0221] In some embodiments, the controller is further configured to, in the second refrigerant recovery mode, control the fourth electromagnetic valve 405 to be closed when a refrigerant recovery stop condition is met, wherein the refrigerant recovery stop condition includes one or more of the following: the multi-split air conditioning system has operated in the second refrigerant recovery mode for a preset time length; or the pressure of the refrigerant entering the compressor 201 is within a preset pressure range.

[0222] It should be noted that the above-mentioned preset pressure range is determined according to the atmospheric pressure of the outdoor environment.

[0223] Optionally, the pressure of the refrigerant of the compressor 201 is detected by the first outdoor pressure sensor 209 arranged at the inlet of the compressor 201 as shown in the figure. FIG. 2

[0224] Based on this, by setting the refrigerant recovery stop condition, the timing of ending the refrigerant recovery can be determined, so that the refrigerant is recovered when the amount of refrigerant in the pipeline of the multi-split air conditioning system is within a reasonable range, thereby avoiding the execution of the second refrigerant recovery mode when there is no refrigerant in the pipeline of the multi-split air conditioning system, causing the multi-split air conditioning system to be abnormal or damaged, and thereby improving the safety and service life of the multi-split air conditioning system.

[0225] Based on the above-mentioned embodiments, the controller is further configured to, in the second refrigerant recovery mode, control the fifth electromagnetic valve 406 to be closed when a refrigerant recovery stop condition is met, wherein the refrigerant recovery stop condition includes one or more of the following: the multi-split air conditioning system has operated in the second refrigerant recovery mode for a preset time length; or the pressure of the refrigerant entering the compressor 201 is within a preset pressure range.

[0226] ​In this embodiment, the indoor unit group 300 corresponding to the indoor unit where the refrigerant leakage occurs is in a closed state. After the refrigerant recovery is completed, by controlling the fourth electromagnetic valve 405 and the fifth electromagnetic valve 406 to be closed, the indoor unit group 300 corresponding to the indoor unit where the refrigerant leakage occurs is free from the refrigerant recovery device 400 and the outdoor unit 200, so as to facilitate the replacement of the indoor unit where the refrigerant leakage occurs without being affected by the refrigerant recovery device 400 and the outdoor unit 200, and improve the convenience of installing or replacing the indoor unit.

[0227] As shown in the control flowchart of the multi-split air conditioning system, the refrigerant recovery process is further described. FIG. 15

[0228] S141, detecting the refrigerant leakage in the indoor unit group and the outdoor unit.

[0229] S142, in the case that the indoor unit group where the refrigerant leakage occurs is detected, controlling the multi-split air conditioning system to run the first refrigerant recovery mode.

[0230] S143, in the case that the outdoor unit where the refrigerant leakage occurs is detected, controlling the multi-split air conditioning system to run the second refrigerant recovery mode.

[0231] S144, in the case that the indoor unit group and the outdoor unit where the refrigerant leakage occurs are detected, keeping the original running mode.

[0232] It should be noted that the original running mode can be a refrigeration mode, a heating mode, a dehumidification mode, and the like.

[0233] In the first refrigerant recovery mode, the outdoor heat exchanger works as a condenser, the indoor heat exchanger works as an evaporator, the first electromagnetic valve is in an open state, the second electromagnetic valve is in a closed state, and the third electromagnetic valve is in a closed state. In the second refrigerant recovery mode, the outdoor heat exchanger works as an evaporator, the indoor heat exchanger works as a condenser, the first electromagnetic valve is in a closed state, the second electromagnetic valve is in an open state, and the third electromagnetic valve is in a closed state.

[0234] Further, the following is the control process of the multi-split air conditioning system in the first refrigerant recovery mode.

[0235] (1) detecting the indoor unit group where the refrigerant leakage occurs. The indoor unit where the refrigerant leakage occurs usually issues a warning information. The warning information is used to indicate that the indoor unit where the refrigerant leakage occurs. The warning information can be in the form of voice, text or light.

[0236] (2) judging whether the multi-split air conditioning system is in a refrigeration mode.​

[0237] (3) If not, switch the multi-split air conditioning system to the cooling mode, and then control the indoor expansion valve corresponding to the indoor unit where the refrigerant leakage occurs to be in the closed state, the first electromagnetic valve to be in the open state, the second electromagnetic valve to be in the closed state, and the third electromagnetic valve to be in the closed state.

[0238] (4) If yes, control the first electromagnetic valve to be in the open state, and control the indoor expansion valve corresponding to the indoor unit where the refrigerant leakage occurs to be in the closed state, the first electromagnetic valve to be in the open state, the second electromagnetic valve to be in the closed state, and the third electromagnetic valve to be in the closed state.

[0239] (5) When the multi-split air conditioning system runs the first refrigerant recovery mode for a preset duration; or when the pressure of the refrigerant entering the compressor is within a preset pressure range, control the fourth electromagnetic valve to be closed, and issue a first replacement information. The first replacement information is used to prompt the user to replace the indoor unit where the refrigerant leakage occurs.

[0240] (6) Control the multi-split air conditioning system to stop running.

[0241] Further, the following is a control process of the multi-split air conditioning system in the second refrigerant recovery mode.

[0242] (1) It is detected that the outdoor unit where the refrigerant leakage occurs exists. The outdoor unit usually issues a warning information. The warning information is used to indicate that the outdoor unit where the refrigerant leakage occurs exists. The warning information can be in the form of voice, text or light.

[0243] (2) It is judged whether the multi-split air conditioning system is in the heating mode.

[0244] (3) If not, switch the multi-split air conditioning system to the heating mode, and then control the first electromagnetic valve to be in the closed state, the second electromagnetic valve to be in the open state, and the third electromagnetic valve to be in the closed state.

[0245] (4) If yes, control the first electromagnetic valve to be in the closed state, the second electromagnetic valve to be in the open state, and the third electromagnetic valve to be in the closed state.

[0246] (5) When the multi-split air conditioning system runs the second refrigerant recovery mode for a preset duration; or when the pressure of the refrigerant entering the compressor is within a preset pressure range, control the fourth electromagnetic valve to be closed, and issue a second replacement information. The second replacement information is used to prompt the user to replace the outdoor unit.

[0247] (6) Control the multi-split air conditioning system to stop running.

[0248] As FIG. 16The control flow chart of the multi-connected air conditioning system is shown, and the refrigerant release process is further explained.

[0249] S151, in the case of completing the first refrigerant recovery mode or completing the second refrigerant recovery mode, if receiving an operation signal for indicating that the multi-connected air conditioning system operates in the cooling mode, controlling the multi-connected air conditioning system in the first refrigerant release mode.

[0250] Wherein, when the multi-connected air conditioning system is in the first refrigerant release mode, the outdoor heat exchanger works as a condenser, the indoor heat exchanger works as an evaporator, the first electromagnetic valve is in the closed state, the second electromagnetic valve is in the closed state, the third electromagnetic valve is in the open state, and the first expansion valve is in the open state.

[0251] S152, in the case of completing the first refrigerant recovery mode or completing the second refrigerant recovery mode, if receiving an operation signal for indicating that the multi-connected air conditioning system operates in the heating mode, controlling the multi-connected air conditioning system in the second refrigerant release mode.

[0252] Wherein, when the multi-connected air conditioning system is in the second refrigerant release mode, the outdoor heat exchanger works as an evaporator, the indoor heat exchanger works as a condenser, the first electromagnetic valve is in the closed state, the second electromagnetic valve is in the closed state, the third electromagnetic valve is in the open state, and the expansion valve is in the open state.

[0253] In addition, the embodiments of the present application provide the hardware structure and / or software module corresponding to the execution of each function. Those skilled in the art should easily realize that, in combination with the modules and algorithm steps of the examples described in the embodiments disclosed in the present application, the embodiments of the present application can be realized in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered beyond the scope of the present application.

[0254] The embodiments of the present application can divide the functional modules of the controller according to the above-mentioned method examples, for example, each functional module can be divided according to each function, or two or more functions can be integrated in one processing module. The above-mentioned integrated module can be realized in the form of hardware or software functional module. Optionally, the division of the modules in the embodiments of the present application is illustrative, and is only a logical functional division. When actually implemented, there can be another division method.

[0255] The embodiments of the present application also provide a hardware structure diagram of a controller, as shown in FIG. 17As shown, the controller 2000 includes a processor 2001, and optionally, a memory 2002 and a communication interface 2003 connected to the processor 2001. The processor 2001, the memory 2002 and the communication interface 2003 are connected through a bus 2004.

[0256] The processor 2001 can be a central processing unit (CPU), a general-purpose processor, a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The processor 2001 can also be other devices that have processing capabilities, such as a circuit, a device, or a software module. The processor 2001 can include multiple CPUs, and the processor 2001 can be a single-CPU processor or a multi-CPU processor. The processor herein can refer to one or more devices, circuits, or processing cores for processing data (e.g., computer program instructions).

[0257] The memory 2002 can be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disk storage, a magnetic disk storage or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and that can be accessed by a computer, without limitation. The memory 2002 can exist independently or be integrated with the processor 2001. The memory 2002 can include computer program code. The processor 2001 is configured to execute the computer program code stored in the memory 2002, thereby implementing the control method provided by the embodiments of the present application.

[0258] The communication interface 2003 can be used to communicate with other devices or communication networks (e.g., Ethernet, radio access network (RAN), wireless local area networks (WLAN), etc.). The communication interface 2003 can be a module, a circuit, a transceiver, or any device capable of enabling communication.

[0259] The bus 2004 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus 2004 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, FIG. 17 Only one thick line is used in the figure to represent the bus, but it does not mean that there is only one bus or only one type of bus.

[0260] The embodiment of the present application further provides a computer readable storage medium, which comprises computer execution instructions, and when the computer execution instructions run on a computer, the computer execution instructions make the computer execute the method provided by the above embodiment.

[0261] The embodiment of the present application further provides a computer program product, which can be directly loaded into a memory and contains software codes, and the computer program product can realize the method provided by the above embodiment after being loaded and executed by a computer.

[0262] Those skilled in the art can realize that the functions described in the above one or more examples can be realized by hardware, software, firmware or any combination thereof. When realized by software, the functions can be stored in a computer readable medium or transmitted as one or more instructions or codes on a computer readable medium. The computer readable medium includes a computer storage medium and a communication medium, wherein the communication medium includes any medium that facilitates the transmission of computer programs from one place to another. The storage medium can be any available medium that can be accessed by a general or special purpose computer.

[0263] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional modules is taken as an example for illustration, and in actual application, the above functions can be completed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.

[0264] In several embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented in other manners. For example, the division of the apparatus embodiments is merely an example, and for example, the division of the modules or units can be different, and each module or unit can include some or all of the functions of the other modules or units. For example, a plurality of modules or components can be combined or integrated into another device, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or modules, and can be in electrical, mechanical or other forms.

[0265] In addition, each function unit in the various embodiments of the present application can be integrated into a processing unit, or each unit can exist physically as a separate entity, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware, or in the form of a software function unit. When the integrated unit is implemented in the form of a software function unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on such an understanding, the technical solutions of the embodiments of the present application essentially, or the part that contributes to the prior art, or all or a part of the technical solutions can be embodied in the form of a software product. The software product is stored in a storage medium, and includes several instructions for causing an apparatus (which can be a single chip, a chip set, or the like) or a processor to perform all or part of the steps of the methods in the various embodiments of the present application. The foregoing storage medium includes: U disk, mobile hard disk, ROM, RAM, magnetic disk, or optical disk, and the like, which are used to store program codes.

[0266] The above is merely specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any change or replacement within the technical scope disclosed in 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. A multi-split air conditioning system, characterized in that, The application relates to a multi-connected air conditioning system, which comprises the following parts: an outdoor unit, which comprises a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve; a plurality of indoor units connected in parallel, each of which comprises an indoor heat exchanger and an indoor expansion valve, and the indoor heat exchanger is connected with the four-way valve through a first pipeline; a refrigerant recovery device, which comprises a first electromagnetic valve, a second electromagnetic valve, a third electromagnetic valve, a first expansion valve and a liquid storage tank; the first opening of the liquid storage tank is connected with the outdoor expansion valve through the first electromagnetic valve, the second opening of the liquid storage tank is connected with the indoor expansion valve through the second electromagnetic valve, the third opening of the liquid storage tank is communicated with the first pipeline through the first expansion valve, and the third opening of the liquid storage tank is arranged at the bottom of the liquid storage tank; the first end of the third electromagnetic valve is connected with the outdoor expansion valve, and the second end of the third electromagnetic valve is connected with the indoor expansion valve; the working modes of the multi-connected air conditioning system comprise a refrigerant release mode; when the multi-connected air conditioning system is in the refrigerant release mode, the first electromagnetic valve is in a closed state, the second electromagnetic valve is in a closed state, the third electromagnetic valve is in an open state, the first expansion valve is in an open state, and one of the outdoor heat exchanger and the indoor heat exchanger works as an evaporator and the other works as a condenser; the refrigerant recovery device further comprises a first supercooling heat exchanger, which comprises a first channel and a second channel; the third opening of the liquid storage tank is communicated with the first pipeline through the first expansion valve and the first channel of the first supercooling heat exchanger; the first end of the third electromagnetic valve is connected with the outdoor expansion valve through the second channel of the first supercooling heat exchanger; the refrigerant recovery device further comprises a first temperature sensor, which is used for detecting the temperature value of the refrigerant flowing out of the first channel of the first supercooling heat exchanger; the outdoor unit further comprises a gas-liquid separator and a first outdoor pressure sensor, which is used for detecting the pressure value of the refrigerant at the inlet of the gas-liquid separator; the multi-connected air conditioning system further comprises a controller, which is configured to: when the multi-connected air conditioning system runs in the refrigerant release mode, the first temperature value detected by the first temperature sensor and the pressure value detected by the first outdoor pressure sensor are acquired; if the difference between the first temperature value and a second temperature value is greater than or equal to a first preset temperature value, the opening degree of the first expansion valve is controlled to be increased, and the second temperature value is a saturated temperature value corresponding to the pressure value detected by the first outdoor pressure sensor; or if the difference between the first temperature value and the second temperature value is greater than the first preset temperature value, the opening degree of the first expansion valve is controlled to be reduced.

2. The multi-split air conditioning system according to claim 1, wherein, The multi-connected air conditioning system has a plurality of working modes, and the plurality of working modes further comprise a first refrigerant recovery mode and a second refrigerant recovery mode. In the first refrigerant recovery mode of the multi-split air conditioning system, the outdoor heat exchanger works as a condenser, the indoor heat exchanger works as an evaporator, the first electromagnetic valve is in an open state, the second electromagnetic valve is in a closed state, the third electromagnetic valve is in a closed state, and the first expansion valve is in a closed state; In the second refrigerant recovery mode of the multi-split air conditioning system, the outdoor heat exchanger works as an evaporator, the indoor heat exchanger works as a condenser, the first electromagnetic valve is in a closed state, the second electromagnetic valve is in an open state, the third electromagnetic valve is in a closed state, and the first expansion valve is in a closed state.

3. The multi-split air conditioning system of claim 2, wherein the refrigerant recovery device further comprises a throttling device and a second subcooling heat exchanger; the second subcooling heat exchanger comprises a third passage and a fourth passage; the third opening of the liquid accumulator further communicates with the first pipeline through the throttling device and the third passage of the second subcooling heat exchanger in sequence; and the second end of the third electromagnetic valve is connected with the indoor expansion valve through the fourth passage of the second subcooling heat exchanger.

4. The multi-split air conditioning system of claim 3, wherein the refrigerant recovery device further comprises a second temperature sensor for detecting a temperature value of the refrigerant flowing out of the third passage of the second subcooling heat exchanger; and the controller is further configured to: obtain a third temperature value detected by the second temperature sensor and a pressure value detected by the first outdoor pressure sensor when the multi-split air conditioning system operates in the refrigerant release mode; end the operation of the refrigerant release mode if a difference between the third temperature value and a second temperature value is greater than or equal to a second preset temperature value, the second temperature value being a saturation temperature value corresponding to the pressure value detected by the first outdoor pressure sensor; or continue the operation of the refrigerant release mode if the difference between the third temperature value and the second temperature value is less than the second preset temperature value.

5. The multi-split air conditioning system of claim 1, wherein the refrigerant recovery device further comprises a fourth electromagnetic valve provided on the first pipeline, a first end of the fourth electromagnetic valve being connected with the four-way valve, and a second end of the fourth electromagnetic valve being connected with the indoor heat exchanger.

6. The multi-split air conditioning system of claim 5, wherein the refrigerant recovery device further comprises a fifth electromagnetic valve provided on the first pipeline, a first end of the fifth electromagnetic valve being connected with the second end of the fourth electromagnetic valve, and a second end of the fifth electromagnetic valve being connected with the indoor heat exchanger.

7. The multi-split air conditioning system of claim 6, wherein the refrigerant recovery device further comprises a second expansion valve; a first end of the second expansion valve is connected with the fourth opening of the liquid accumulator, and a second end of the second expansion valve communicates with a second pipeline between the fourth electromagnetic valve and the fifth electromagnetic valve; or the second pipeline is a pipeline between the fourth electromagnetic valve and the fifth electromagnetic valve. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A first end of the second expansion valve is communicated with the third pipeline, and a second end of the second expansion valve is communicated with the second pipeline.

8. The multi-split air conditioning system according to claim 6, wherein, The refrigerant recovery device further comprises: A first stop valve is arranged on a pipeline between the four-way valve and the fourth electromagnetic valve, a first end of the first stop valve is connected with the four-way valve through the pipeline, and a second end of the first stop valve is connected with a first end of the fourth electromagnetic valve through the pipeline; A second stop valve is arranged on a pipeline between the fourth electromagnetic valve and the indoor heat exchanger, a first end of the second stop valve is connected with a second end of the fourth electromagnetic valve through the pipeline, and a second end of the second stop valve is connected with the indoor heat exchanger of each indoor unit through the pipeline; A third stop valve is arranged on a pipeline between the outdoor expansion valve and the first electromagnetic valve, a first end of the third stop valve is connected with the outdoor expansion valve through the pipeline, and a second end of the third stop valve is connected with a first end of the first electromagnetic valve through the pipeline; A fourth stop valve is arranged on a pipeline between the second electromagnetic valve and the indoor heat exchanger, a first end of the fourth stop valve is connected with a second end of the second electromagnetic valve through the pipeline, and a second end of the fourth stop valve is connected with the indoor expansion valve of each indoor unit through the pipeline.

9. The multi-split air conditioning system according to claim 8, wherein, The outdoor unit further comprises: A fifth stop valve is arranged on a pipeline between the four-way valve and the first stop valve, a first end of the fifth stop valve is connected with the four-way valve through the pipeline, and a second end of the fifth stop valve is connected with a first end of the first stop valve through the pipeline; A sixth stop valve is arranged on a pipeline between the outdoor expansion valve and the third stop valve, a first end of the sixth stop valve is connected with the outdoor expansion valve through the pipeline, and a second end of the sixth stop valve is connected with a first end of the third stop valve through the pipeline.

10. The multi-split air conditioning system according to claim 9, wherein, The outdoor unit further comprises: A sixth electromagnetic valve is arranged on a pipeline between the four-way valve and the fifth stop valve, a first end of the sixth electromagnetic valve is connected with the four-way valve through the pipeline, and a second end of the sixth electromagnetic valve is connected with a first end of the fifth stop valve through the pipeline; A seventh electromagnetic valve is arranged on a pipeline between the outdoor expansion valve and the sixth stop valve, a first end of the seventh electromagnetic valve is connected with the outdoor expansion valve through the pipeline, and a second end of the seventh electromagnetic valve is connected with a first end of the sixth stop valve through the pipeline.

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