CN115264620A

CN115264620A - Multi-split air conditioning system

Info

Publication number: CN115264620A
Application number: CN202210855318.2A
Authority: CN
Inventors: 颜鹏; 孙杨; 郭小惠; 韩飞
Original assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Current assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Priority date: 2022-07-19
Filing date: 2022-07-19
Publication date: 2022-11-01
Anticipated expiration: 2042-07-19
Also published as: CN115264620B

Abstract

The application discloses multi-split air conditioning system relates to household electrical appliances technical field, can let the refrigerant recovery that leaks and utilize more thoroughly. This multi-split air conditioning system includes: the indoor unit comprises a plurality of indoor units, each indoor unit comprises an indoor heat exchanger, a first indoor expansion valve and a second indoor expansion valve, and the first end of each indoor heat exchanger is connected with the second end of the first indoor expansion valve and the second end of the second indoor expansion valve respectively; the outdoor unit comprises a compressor, an outdoor heat exchanger, a first four-way valve and a second four-way valve; the return air port of the compressor is connected with the first pipeline; the refrigerant recovery device comprises a first electromagnetic valve, a third electromagnetic valve, a first expansion valve and a liquid storage tank; the second end of the outdoor heat exchanger is connected with the first opening of the liquid storage tank through a first electromagnetic valve and is connected with the second end of each indoor heat exchanger through a third electromagnetic valve; and a third opening of the liquid storage tank is respectively communicated with the first pipeline and the second pipeline through a first expansion valve.

Description

Multi-split air conditioning system

Technical Field

The application relates to the technical field of household appliances, in particular to a multi-split air conditioning system.

Background

With the development of economic society, air conditioners are more and more widely used in various places such as entertainment, home and work. When a plurality of small areas in the same area need to use air conditioners, a multi-split air conditioning system composed of an outdoor unit and a plurality of indoor units is often adopted to regulate and control the room temperature of multiple areas in consideration of saving of electric energy. In the use process 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 required to transfer heat. However, the heat transfer pipe may be corroded by exposure to the outdoor environment for a long time, and thus may cause leakage of the refrigerant.

In order to avoid the risk caused by refrigerant leakage, in the related art, a pair of electronic expansion valves are added to the inlet and the outlet of each indoor unit of a multi-split air conditioning system for synchronously controlling refrigeration or heating, so that the refrigerant leaked in the indoor unit is blocked from flowing into the indoor environment. However, in the above-mentioned related art method, the leaked refrigerant cannot be completely recovered and utilized, and may be directly discharged to the outdoor environment, thereby causing a problem of environmental pollution.

Disclosure of Invention

The embodiment of the application provides a multi-split air conditioning system for let the refrigerant of leakage more thoroughly retrieve and utilize, in order to improve multi-split air conditioning system's feature of environmental protection and energy-conservation nature.

In a first aspect, an embodiment of the present application provides a multi-split air conditioning system, including: the indoor unit comprises a plurality of indoor units, each indoor unit comprises an indoor heat exchanger, a first indoor expansion valve and a second indoor expansion valve, and the first end of each indoor heat exchanger is connected with the second end of the first indoor expansion valve and the second end of the second indoor expansion valve respectively; the outdoor unit comprises a compressor, an outdoor heat exchanger, a first four-way valve and a second four-way valve; the first end of the second four-way valve is connected with the first end of each first indoor expansion valve through a first pipeline, the second end of the second four-way valve is connected with the air outlet of the compressor, and the third end of the second four-way valve is connected with the first end of each second indoor expansion valve through a second pipeline; the first end of the first four-way valve is connected with the first pipeline, the second end of the first four-way valve is connected with the air outlet of the compressor, and the fourth end of the first four-way valve is connected with the first end of the outdoor heat exchanger; the return air port of the compressor is connected with the first pipeline; the refrigerant recovery device comprises a first electromagnetic valve, a third electromagnetic valve, a first expansion valve and a liquid storage tank; the second end of the outdoor heat exchanger is connected with the first opening of the liquid storage tank through a first electromagnetic valve and is connected with the second end of each indoor heat exchanger through a third electromagnetic valve; and a third opening of the liquid storage tank is respectively communicated with the first pipeline and the second pipeline through a first expansion valve.

In order to improve the refrigerant discharge efficiency, the third opening is usually provided at the bottom of the liquid storage tank.

The technical scheme provided by the embodiment of the application at least has the following beneficial effects: in the multi-split air conditioning system, a refrigerant recovery device is arranged between the outdoor unit and the indoor unit. When the refrigerant leaks, the running modes of the outdoor unit and the indoor unit to be entered are combined, the flowing direction of the refrigerant in the multi-split air-conditioning system is controlled by controlling the closing and opening states of the three electromagnetic valves, namely the first electromagnetic valve, the second electromagnetic valve and the third electromagnetic valve, and the closing and opening state of the first expansion valve in the refrigerant recovery device, the refrigerant in the multi-split air-conditioning system is firstly introduced into the liquid storage tank of the refrigerant recovery device from the first opening, the leaked refrigerant is completely recovered, the problem that the refrigerant is discharged out of the outdoor environment to cause environmental pollution is avoided, and the environmental friendliness of the multi-split air-conditioning system is improved. Furthermore, after the refrigerant leakage condition is repaired, when the multi-split air-conditioning system enters a normal refrigeration or heating operation mode again, the refrigerant recovered by the refrigerant recovery device is released into the first pipeline and the second 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.

In some embodiments, the refrigerant recovery device further includes a second solenoid valve; and a second opening of the liquid storage tank is connected with a second end of the indoor heat exchanger in each indoor unit through a second electromagnetic valve.

Therefore, the first end of the second electromagnetic valve is connected with the second opening of the liquid storage tank through a pipeline, the second end of the second electromagnetic valve is connected with the second end of the indoor heat exchanger of each indoor unit through a pipeline, a branch of the refrigerant flowing to the liquid storage tank is formed, and the refrigerant leaked from the outdoor unit in the multi-split air-conditioning system is recovered.

In some embodiments, the multi-split air conditioning system has a plurality of operation modes, and the plurality of operation modes at least 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, the first expansion valve is in a closed state, the first indoor expansion valve is in an open state, and the second indoor expansion valve is in an open 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, the first expansion valve is in a closed state, the first indoor expansion valve is in a closed state, and the second indoor expansion valve is in an open state. When the multi-split air conditioning system is in a 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 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, the first indoor expansion valve is in an open state, and the second indoor expansion valve is in an open state.

Based on the method, the multi-split air conditioning system can provide working modes corresponding to different scenes. Specifically, when the refrigerant leaked from the indoor unit needs to be recovered, the multi-split air conditioning system can be switched to the first refrigerant recovery mode, and the refrigerant leaked from the indoor unit is recovered by the refrigerant recovery device. When the refrigerant leaked from the outdoor unit needs to be recovered, the multi-split air conditioning system can be switched to the second refrigerant recovery mode, and the refrigerant leaked from the outdoor unit can be recovered through the refrigerant recovery device. When the refrigerant recovered in the refrigerant recovery device needs to be utilized, the multi-split air-conditioning system can be adjusted to the refrigerant release mode, and the recovered refrigerant is released to the first pipeline and the second pipeline so that the multi-split air-conditioning system can use the recovered refrigerant in the process of refrigerating operation or heating operation.

In addition, it should be noted that the multi-split air conditioning system may also have the following multiple operation modes: a synchronous refrigeration mode, a first asynchronous refrigeration and heating mode and a second asynchronous refrigeration and heating mode; in any mode of the first asynchronous cooling and heating mode and the second asynchronous cooling and heating mode, the indoor units comprise at least one first indoor unit to be subjected to cooling operation and at least one second indoor unit to be subjected to heating operation.

Specifically, when the multi-split air conditioning system is in a synchronous refrigeration mode, the outdoor heat exchanger works as a condenser, each 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 indoor expansion valve of each indoor unit and the second indoor expansion valve of each indoor unit are in an open state.

When the multi-split air conditioning system is in a synchronous heating mode, the outdoor heat exchanger works as an evaporator, each 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, the first indoor expansion valve of each indoor unit is in a closed state, and the second indoor expansion valve of each indoor unit is in an open state.

When the multi-split air conditioning system is in the first asynchronous cooling and heating mode, the outdoor heat exchangers work as condensers, all indoor heat exchangers of all first indoor units in the indoor group work as evaporators, and all indoor heat exchangers of all second indoor units in the indoor group work as condensers; a first indoor expansion valve of the first indoor unit is in an open state, and a second indoor expansion valve of the first indoor unit is in a closed state; a second indoor expansion valve of a second indoor unit is in an open state, and a first indoor expansion valve of the second indoor unit is in a closed state; the first solenoid valve is in a closed state, the second solenoid valve is in a closed state, and the third solenoid valve is in an open state.

Fourthly, when the multi-split air conditioning system is in the second asynchronous refrigeration and heating mode, the outdoor heat exchangers work as evaporators, all indoor heat exchangers of all first indoor units in the indoor group work as evaporators, and all indoor heat exchangers of all second indoor units in the indoor group work as condensers; a first indoor expansion valve of the first indoor unit is in an open state, and a second indoor expansion valve of the first indoor unit is in a closed state; the first indoor expansion valve of the second indoor unit is in a closed state, and the second indoor expansion valve of the first indoor unit is in an open state.

In some embodiments, each indoor unit further comprises a third indoor expansion valve; the third indoor expansion valve is arranged on a pipeline between the second electromagnetic valve and the second end of the indoor heat exchanger; when the multi-split air conditioning system is in the first refrigerant recovery mode, the third indoor expansion valve in the indoor unit, where refrigerant leakage occurs, is in a closed state.

Therefore, the first end of each third indoor expansion valve is communicated with the second end of the corresponding indoor heat exchanger through a pipeline, when the multi-split air-conditioning system is in the first refrigerant recovery mode, the third indoor expansion valve of the indoor unit with refrigerant leakage is controlled to be closed, the refrigerant is prevented from continuously entering the indoor unit with refrigerant leakage, the refrigerant in the indoor unit with refrigerant leakage is prevented from leaking into the indoor environment, and the safe use of a user on the multi-split air-conditioning system is further ensured.

In some embodiments, the refrigerant recovery device further includes a first supercooling heat exchanger, and the first supercooling heat exchanger includes a first channel and a second channel; a third opening of the liquid storage tank is respectively communicated with the first pipeline and the second pipeline through a first expansion valve and a first channel of the first supercooling heat exchanger in sequence; and the first end of the third electromagnetic valve is connected with the second end of the outdoor heat exchanger through the second channel of the first supercooling heat exchanger. Therefore, the refrigerant flow recovered in the refrigerant recovery device passes through the first channel of the first cold heat exchanger, and the refrigerant flow passes through the second channel of the first cold heat exchanger in the operation process of the multi-split air-conditioning system. The second channel cools the refrigerant flowing through the second channel to release corresponding heat. The first channel heats the recovered refrigerant flowing through the first channel by using the heat released by the second channel, so that the liquid refrigerant in the recovered refrigerant in two phases (gas state and liquid state) is converted into the gas refrigerant, the content of the liquid refrigerant in the refrigerant released by the refrigerant recovery device is reduced, the content of the gas refrigerant in the released recovered refrigerant is improved, and the use efficiency of the recovered refrigerant is ensured.

In addition, in the process of releasing the recovered refrigerant when the multi-split air conditioning system is in the synchronous refrigeration working mode, the refrigerant recovery device releases the recovered refrigerant to the compressor of the outdoor unit, the content of the liquid refrigerant in the refrigerant released by the refrigerant recovery device is reduced, the liquid return of the compressor can be reduced, and the service life of the compressor is prolonged.

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

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 supercooling 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. And controlling the opening degree of the first expansion valve based on the size relation between the temperature difference value and the first preset temperature value so as to ensure that the opening degree of the first expansion valve is in a reasonable range, thereby ensuring that the quantity of the refrigerant released by the refrigerant recovery device is in a reasonable range. On one hand, the problem that the multi-split air-conditioning system cannot process the refrigerant timely due to too much refrigerant in the pipeline of the whole multi-split air-conditioning system caused by too much refrigerant released by the refrigerant recovery device is avoided; on the other hand, the problem that the refrigerant quantity released by the refrigerant recovery device is too small, so that the refrigerant quantity in the pipeline of the whole multi-split air-conditioning system is too small, the working efficiency of the multi-split air-conditioning system is reduced, and the refrigerating speed is reduced is solved.

In some embodiments, the refrigerant recovery device further comprises a throttling device and a second supercooling heat exchanger; the second supercooling heat exchanger comprises a third channel and a fourth channel; the third opening of the liquid storage tank is also communicated with the first pipeline through a third channel of the throttling device and the second supercooling heat exchanger in sequence; and a second end of the third electromagnetic valve is connected with the indoor expansion valve through a fourth channel of the second supercooling heat exchanger.

On the basis, the refrigerant recovered in the refrigerant recovery device flows through a third channel of the supercooling heat exchanger after being throttled by the throttling device; and in the operation process of the multi-split air conditioning system, the refrigerant flows through the fourth channel of the supercooling heat exchanger. The fourth channel cools the refrigerant flowing through the fourth channel to release corresponding heat. The third channel heats the recovered refrigerant flowing through the third channel by using the heat released by the fourth channel, so that the liquid refrigerant in the recovered refrigerant in two phases (gas state and liquid state) is converted into the gaseous refrigerant, the content of the liquid refrigerant in the refrigerant released by the refrigerant recovery device is reduced, the content of the gaseous refrigerant in the released recovered refrigerant is improved, and the use efficiency of the recovered refrigerant is ensured.

In some embodiments, the refrigerant recovery device further includes a second temperature sensor, where the second temperature sensor is configured to detect a temperature value of the refrigerant flowing out of the third channel of the second supercooling heat exchanger; a controller further configured to: when the multi-split air-conditioning system operates in a refrigerant release mode, acquiring a third temperature value detected by the second temperature sensor and a pressure value detected by the first outdoor pressure sensor; if the difference value between the third temperature value and the second temperature value is greater than or equal to a second preset temperature value, ending the operation of the refrigerant release mode, wherein the second temperature value is a saturation temperature value corresponding to the pressure value detected by the first outdoor pressure sensor; or if the difference value between the third temperature value and the second temperature value is smaller than a second preset temperature value, continuing to operate the refrigerant release mode.

In this embodiment, a 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 third channel of the second supercooling heat exchanger with the saturation temperature corresponding to the pressure value of the refrigerant at the inlet of the gas-liquid separator, that is, the second temperature value. The releasing process of the refrigerant recovery device is reasonably controlled based on the size relation between the temperature difference value and the second preset temperature value, so that the refrigerant recovery device can release the refrigerant under the condition of sufficient refrigerant, the refrigerant releasing mode is still executed under the condition that no refrigerant exists in the refrigerant recovery device, the refrigerant quantity in the multi-split air-conditioning system is small, and the working efficiency of the multi-split air-conditioning system is reduced.

In some embodiments, the refrigerant recycling device further includes a fourth solenoid valve and a fifth solenoid valve, the fourth solenoid valve is disposed on the first pipe, a first end of the fourth solenoid valve is connected to the first end of the second four-way valve, a second end of the fourth solenoid valve is connected to the first end of the first indoor expansion valve, the fifth solenoid valve is disposed on the second pipe, a first end of the fifth solenoid valve is connected to the third end of the second four-way valve, and a second end of the fifth solenoid valve is connected to the first end of the second indoor expansion valve.

Based on the control method, when the multi-split air conditioning system operates in any one of a synchronous refrigeration mode, a first asynchronous refrigeration and heating mode, a second asynchronous refrigeration and heating mode, a first refrigerant recovery mode, a second refrigerant recovery mode and a refrigerant release mode, the fourth electromagnetic valve and the fifth electromagnetic valve are controlled to be in an open state, so that the refrigerant can circulate in the corresponding pipelines.

Additionally, the controller is further configured to: under a first refrigerant recovery mode and a second refrigerant recovery mode, when a refrigerant recovery stopping condition is met, controlling a fourth electromagnetic valve and a fifth electromagnetic valve to be closed; the refrigerant recovery stopping condition comprises one or more of the following conditions: the time length of the multi-split air conditioning system operating in the first refrigerant recovery mode or the second refrigerant recovery mode reaches a preset time length; or the pressure of the refrigerant entering the compressor is within a preset pressure range. Based on this, by setting the refrigerant recovery stopping condition, the time for finishing the refrigerant recovery can be determined, so that the refrigerant is recovered when the refrigerant quantity in the pipeline of the multi-split air-conditioning system is in a reasonable range, and the problem that the multi-split air-conditioning system is abnormal or damaged due to the fact that the first refrigerant recovery mode or the second refrigerant recovery mode is still executed under the condition that no refrigerant exists in the pipeline of the multi-split air-conditioning system is avoided, and the safety and the service life of the multi-split air-conditioning system are further improved.

In some embodiments, the refrigerant recovery device further includes a sixth solenoid valve and a seventh solenoid valve, the sixth solenoid valve is disposed on the first pipeline, a first end of the sixth solenoid valve is connected to a second end of the fourth solenoid valve, and a second end of the sixth solenoid valve is connected to a first end of the first indoor expansion valve; the seventh electromagnetic valve is arranged on the second pipeline, a first end of the seventh electromagnetic valve is connected with a second end of the fifth electromagnetic valve, and a second end of the seventh electromagnetic valve is connected with a first end of the second indoor expansion valve.

Based on the control method, when the multi-split air conditioning system operates in any one of a synchronous refrigeration mode, a first asynchronous refrigeration and heating mode, a second asynchronous refrigeration and heating mode, a first refrigerant recovery mode and a second refrigerant recovery mode, and a refrigerant release mode, the sixth electromagnetic valve and the seventh electromagnetic valve are controlled to be in an open state, so that the refrigerant can circulate in the corresponding pipelines.

Additionally, in some embodiments, each indoor unit further comprises a third indoor expansion valve; the third indoor expansion valve is arranged on a pipeline between the second electromagnetic valve and the second end of the indoor heat exchanger; when the multi-split air conditioning system is in the first refrigerant recovery mode, the third indoor expansion valve in the indoor unit, where refrigerant leakage occurs, is in a closed state.

In addition, in some embodiments, the outdoor unit further includes an outdoor expansion valve disposed on a pipe between the second end of the outdoor heat exchanger and the first solenoid valve; and when the multi-split air conditioning system is in the second refrigerant recovery mode, the outdoor expansion valve is in the maximum opening value.

Therefore, when the multi-split air-conditioning system operates in the second refrigerant recovery mode, the outdoor expansion valve is controlled to be in the maximum opening value, so that the refrigerant in the pipeline communicated with the outdoor expansion valve can be recovered to the refrigerant recovery device through the outdoor unit and the indoor unit more quickly, the recovery speed of the refrigerant leaked from the outdoor unit is increased, and the refrigerant recovery efficiency of the multi-split air-conditioning system is ensured.

Additionally, in some embodiments, the controller is further configured to: under the first refrigerant recovery mode or the second refrigerant recovery mode, when the refrigerant recovery stopping condition is met, controlling the sixth electromagnetic valve and the seventh electromagnetic valve to be closed; the refrigerant recovery stopping condition comprises one or more of the following conditions: the time for the multi-split air conditioning system to operate in the first refrigerant recovery mode or the second refrigerant recovery mode reaches the preset time; or the pressure of the refrigerant entering the compressor is within a preset pressure range. Therefore, the third indoor expansion valve corresponding to the indoor unit with refrigerant leakage in the indoor unit is in a closed state. After the refrigerant is recovered, the sixth electromagnetic valve and the seventh electromagnetic valve are controlled to be closed, so that indoor units with refrigerant leakage in the indoor unit are freely separated from the refrigerant recovery device and the outdoor unit, the indoor units with refrigerant leakage are not influenced by the refrigerant recovery device and the outdoor unit in the process of replacing the indoor units with refrigerant leakage, and the convenience for installing or replacing the indoor units is improved.

In some embodiments, the refrigerant recovery device further includes a second expansion valve; a first end of the second expansion valve is connected with a fourth opening of the liquid storage tank, a second end of the second expansion valve is respectively communicated with a third pipeline and a fourth pipeline, the third pipeline is a pipeline between a fourth electromagnetic valve and a sixth electromagnetic valve, and the fourth pipeline is a pipeline between a fifth electromagnetic valve and a seventh electromagnetic valve; or the first end of the second expansion valve is communicated with a fifth pipeline, the second end of the second expansion valve is respectively communicated with the third pipeline and the fourth pipeline, and the fifth pipeline is a pipeline between the first electromagnetic valve and the first opening of the liquid storage tank.

In this embodiment, in the refrigerant recovery process, when the amount of refrigerant circulating in the multi-split air conditioning system is smaller and smaller, and the low pressure of the multi-split air conditioning system is closer and closer to the preset pressure range (generally, the atmospheric pressure of the environment where the multi-split air conditioning system is located), the discharge temperature of the compressor is higher and higher, which affects the reliability of the compressor. Based on this, a second expansion valve is added between the fourth opening of the liquid storage tank and the third pipeline and between the fourth opening of the liquid storage tank and the fourth pipeline, or a second expansion valve is added between the fifth pipeline and the third pipeline and between the fifth pipeline and the fourth pipeline, so that in the refrigerant recovery process, the second expansion valve is opened, and a part of the refrigerant bypasses the compressor, thereby reducing the exhaust temperature of the compressor, achieving the purpose of reducing the temperature of the compressor, and ensuring the reliability of the compressor in the refrigerant recovery process.

In addition, in the process of refrigerant recovery, the refrigerant entering the liquid storage tank may be a gas-phase refrigerant and a liquid-phase refrigerant, and under the condition that the refrigerant entering the liquid storage tank is the two-phase refrigerant, the amount of the refrigerant stored in the liquid storage tank can be reduced due to the small average density of the two-phase refrigerant, so that the refrigerant recovery effect is influenced. Therefore, in the process of refrigerant recovery, the second expansion valve is opened, and the bypass gaseous refrigerant enters, so that the refrigerant recovery effect is improved.

In a second aspect, an embodiment of the present application provides a method for controlling a multi-split air conditioning system, where the method is applied to the multi-split air conditioning system of the first aspect, and the method includes:

and responding to a starting signal of the multi-split air conditioning system, and controlling the multi-split air conditioning system to be in a refrigerant release mode under the condition that a refrigerant is detected in a liquid storage tank of the refrigerant recovery device.

When the multi-split air conditioning system is in a 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 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, the first indoor expansion valve is in an open state, and the first indoor expansion valve is in an open state.

In some embodiments, the refrigerant recovery device further includes: the first supercooling heat exchanger and the outdoor unit further include a gas-liquid separator, and the method includes: acquiring a first temperature value of a refrigerant flowing out of a first channel of a first supercooling heat exchanger and a pressure value of the refrigerant at an inlet of a gas-liquid separator; if the difference value between the first temperature value and the second temperature value is larger than or equal to a first preset temperature value, controlling the first expansion valve to increase the opening degree, wherein the second temperature value is a saturation temperature value corresponding to the pressure value of the refrigerant at the inlet of the gas-liquid separator; or if the difference value between the first temperature value and the second temperature value is greater than a first preset temperature value, controlling the first expansion valve to reduce the opening degree.

In some embodiments, the refrigerant recovery device further includes: a second subcooling heat exchanger; the method further comprises the following steps: when the multi-split air-conditioning system operates in a refrigerant release mode, acquiring a third temperature value of a refrigerant flowing out of a third channel of the second supercooling heat exchanger and a pressure value of the refrigerant at an inlet of the gas-liquid separator; if the difference value between the third temperature value and the second temperature value is greater than or equal to a second preset temperature value, ending the operation of the refrigerant release mode, wherein the second temperature value is a saturation temperature value corresponding to the pressure value of the refrigerant at the inlet of the gas-liquid separator; or if the difference value between the third temperature value and the second temperature value is smaller than a second preset temperature value, continuing to operate the refrigerant release mode.

In a third aspect, an embodiment of the present application provides a control device for a multi-split air conditioning system, including: one or more processors; one or more memories; wherein the one or more memories are for storing computer program code comprising computer instructions which, when executed by the one or more processors, cause the controller to perform the method provided in the second aspect and possible implementations.

In a fourth aspect, embodiments of the present application provide a computer-readable storage medium including computer instructions that, when executed on a computer, cause the computer to perform the method provided in the second aspect and possible implementations.

In a fifth aspect, embodiments of the present application provide a computer program product containing computer instructions, which when executed on a computer, cause the computer to perform the method provided in the second aspect and possible implementation manners.

It should be noted that all or part of the computer instructions may be stored on the computer readable storage medium. The computer readable storage medium may be packaged with or separately from a processor of the controller, which is not limited in this application.

The beneficial effects described in the second aspect to the fifth aspect in the present application may refer to the beneficial effect analysis of the first aspect, and are not described herein again.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the example serve to explain the principles of the invention and not to limit the invention.

Fig. 1 is a schematic structural view of a multi-split air conditioning system according to some embodiments;

FIG. 2 is a schematic diagram of another multi-split air conditioning system according to some embodiments;

FIG. 3 is a schematic diagram of another multi-split air conditioning system according to some embodiments;

FIG. 4 is a schematic diagram of another multi-split air conditioning system according to some embodiments;

FIG. 5 is a schematic diagram of another multi-split air conditioning system according to some embodiments;

fig. 6 is a control flowchart of a multi-split air conditioning system according to some embodiments;

FIG. 7 is a control flow diagram of another multi-split air conditioning system according to some embodiments;

fig. 8 is a schematic diagram illustrating a refrigerant cycle of a multi-split air conditioning system according to some embodiments;

fig. 9 is a schematic diagram illustrating a refrigerant cycle of another multi-split air conditioning system according to some embodiments;

fig. 10 is a schematic diagram illustrating a refrigerant cycle of another multi-split air conditioning system according to some embodiments;

fig. 11 is a schematic diagram illustrating a refrigerant cycle of another multi-split air conditioning system according to some embodiments;

fig. 12 is a schematic diagram illustrating a refrigerant cycle of another multi-split air conditioning system according to some embodiments;

fig. 13 is a schematic diagram illustrating a refrigerant cycle of another multi-split air conditioning system according to some embodiments;

fig. 14 is a schematic diagram illustrating a refrigerant cycle of another multi-split air conditioning system according to some embodiments;

fig. 15 is a control flow diagram of a multi-split air conditioning system according to some embodiments;

FIG. 16 is a control flow diagram of another multi-split air conditioning system according to some embodiments;

fig. 17 is a schematic diagram of a hardware configuration of a controller according to some embodiments.

Reference numerals: 100-a multi-split air conditioning system; 200-outdoor unit; 201-a compressor; 202A-a first four-way valve; 202B-a second four-way valve; 203-outdoor heat exchanger; 204-outdoor expansion valve; 205-gas-liquid separator; 206-an oil separator; 207-oil return capillary; 208-a one-way valve; 209-a first outdoor pressure sensor; 210-a second outdoor pressure sensor; 211A-a seventh stop valve; 211B-eighth stop valve; 212-ninth stop valve; 213A-eighth solenoid valve; 213B-ninth solenoid valve; 214-tenth solenoid valve; 215-outdoor fan; 300-indoor unit: 300A-a first indoor unit; 300B-a second indoor unit; 301A-a first indoor heat exchanger; 302A-a third indoor expansion valve of the first indoor unit; 303A-a first indoor fan; 304A-a first indoor expansion valve of the first indoor unit; 305A-a second indoor expansion valve of the first indoor unit; 301B-a second indoor heat exchanger; 302B-a third indoor expansion valve of the second indoor unit; 303B-a second indoor fan; 304B — a first indoor expansion valve of the second indoor unit; 305B — a second indoor expansion valve of the second indoor unit; 308A-a thirteenth stop valve; 308B-a fourteenth stop valve; 400-refrigerant recovery unit; 401-a first solenoid valve; 402-a second solenoid valve; 403-a third solenoid valve; 404-a liquid storage tank; 405A-a fourth solenoid valve; 405B-a fifth solenoid valve; 406A-a sixth solenoid valve; 406B-a seventh solenoid valve; 407A-first stop valve; 408A-a third stop valve; 407B-second stop valve; 408B-a fourth stop valve; 409-a fifth stop valve; 410-a sixth stop valve; 411 — first expansion valve; 412-a second expansion valve; 413-a first subcooling heat exchanger; 414-a throttling device; 415-a second subcooling heat exchanger; 416 — a first channel; 417 — a second channel; 418 — a third channel; 419-fourth channel.

Detailed Description

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, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless otherwise specified.

In the description of the present application, it is to be noted that the terms "connected" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected, unless explicitly stated or limited otherwise. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art. In addition, when a pipeline is described, the terms "connected" and "connected" are used in this application to have a meaning of conducting. The specific meaning is to be understood in conjunction with the context.

Unless the context requires otherwise, throughout the description and the claims, the term "comprise" and its other forms, such as the third person's singular form "comprising" and the present participle form "comprising" are to be interpreted in an open, inclusive sense, i.e. as "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" and the like are intended to indicate that a particular feature, structure, material, or characteristic associated with the embodiment or example is included in at least one embodiment or example of the present disclosure. The schematic representations of the above terms are not necessarily referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics may be included in any suitable manner in any one or more embodiments or examples.

In the embodiments of the present application, words such as "exemplary" or "for example" are used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "e.g.," is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, use of the word "exemplary" or "such as" is intended to present concepts related in a concrete fashion.

As background art, in order to avoid the risk caused by refrigerant leakage, in the related art, a pair of electronic expansion valves is added to an inlet and an outlet of each indoor unit of a multi-split air conditioning system for synchronously controlling cooling or heating, so as to block the refrigerant leaking from the indoor units from flowing into an indoor environment. However, in the above-mentioned related art method, the leaked refrigerant cannot be completely recovered and utilized, and may be directly discharged to the outdoor environment, thereby causing environmental pollution.

In view of the above, an embodiment of the present application provides a multi-split air conditioning system, in which a refrigerant recovery device is disposed between an outdoor unit and an indoor unit. When the refrigerant leaks, the running modes of the outdoor unit and the indoor unit to be entered are combined, the flowing direction of the refrigerant in the multi-split air-conditioning system is controlled by controlling the closing and opening states of the three electromagnetic valves, namely the first electromagnetic valve, the second electromagnetic valve and the third electromagnetic valve, and the closing and opening state of the first expansion valve in the refrigerant recovery device, the refrigerant in the multi-split air-conditioning system is firstly introduced into the liquid storage tank of the refrigerant recovery device from the first opening, the leaked refrigerant is completely recovered, the problem that the refrigerant is discharged out of the outdoor environment to cause environmental pollution is avoided, and the environmental friendliness of the multi-split air-conditioning system is improved. Furthermore, after the refrigerant leakage condition is repaired, when the multi-split air-conditioning system enters a normal refrigeration or heating operation mode again, the refrigerant recovered by the refrigerant recovery device is released into the first pipeline and the second 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.

To further describe the solution of the present application, as shown in fig. 1, a schematic structural diagram of a multi-split air conditioning system according to an embodiment of the present application is provided. The multi-split air conditioning system 100 includes an outdoor unit 200, an indoor unit 300, and a refrigerant recovery device 400.

Outdoor unit 200

The outdoor unit 200 of the multi-split air conditioning system 100 includes: a compressor 201, a four-way valve group (a first four-way valve 202A and a second four-way valve 202B shown in fig. 1), and an outdoor heat exchanger 203, which are connected in this order. Wherein, the air outlet of compressor 201 is connected to the second end of first four-way valve 202A and the second end of second four-way valve 202B, and the air return port of compressor 201 is connected to the pipeline between the first end of first four-way valve 202A and the indoor heat exchanger; a first end of outdoor heat exchanger 203 is connected to a fourth end of first four-way valve 202A.

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 a check valve 208.

Specifically, as shown in fig. 1, the air outlet of compressor 201 is connected to a first end of oil separator 206 via a pipeline, a second end of oil separator 206 is connected to check valve 208 via a pipeline, check valve 208 is connected to a second end of first four-way valve 202A and a second end of second four-way valve 202B via pipelines, respectively, a fourth end of first four-way valve 202A is connected to outdoor heat exchanger 203 via a pipeline, and outdoor heat exchanger 203 is connected to outdoor expansion valve 204 via a pipeline. Wherein, the third end of the oil separator 206 is connected with the first opening of the gas-liquid separator 205 through a pipeline; a second opening of gas-liquid separator 205 is connected to a first end of first four-way valve 202A and a first end of second four-way valve 202B, respectively, via a pipe.

Further, the four ports of first four-way valve 202A and second four-way valve 202B as shown in FIG. 1 (i.e., the first end of first four-way valve 202A and the first end of second four-way valve 202B are S ports, the second end of first four-way valve 202A and the second end of second four-way valve 202B are D ports, the third end of first four-way valve 202A and the third end of second four-way valve 202B are E ports, and the fourth end of first four-way valve 202A and the fourth end of second four-way valve 202B are C ports) are respectively connected to the air outlet of compressor 201, outdoor heat exchanger 203, the return air inlet of compressor 201, and the indoor heat exchangers of the respective indoor units. The first four-way valve 202A and the second four-way valve 202B are used for switching between a cooling mode and a heating mode by changing a flow direction of a refrigerant in a system pipeline.

Based on the above embodiments, in some embodiments, the outdoor unit 200 further includes an outdoor refrigerant leakage detection device (not shown). The outdoor refrigerant leakage detection device is used for detecting refrigerant leakage of the outdoor unit.

Exemplarily, a detection result of the outdoor refrigerant leakage detection device is used for indicating whether refrigerant leakage occurs in the outdoor unit; and if the detection result of the outdoor refrigerant leakage detection device indicates that the outdoor unit has refrigerant leakage, the multi-split air-conditioning system should operate in a second refrigerant recovery mode.

In still other embodiments, the outdoor unit 200 further includes a first outdoor pressure sensor 209 and a second outdoor pressure sensor 210, wherein the first outdoor pressure sensor 209 is disposed at the first port of the gas-liquid separator 205 and is used for detecting the pressure of the refrigerant entering the compressor 201, and as shown in fig. 1, the pressure of the refrigerant entering the compressor 201 is represented by detecting the pressure value of the refrigerant at the inlet of the gas-liquid separator 205 through the first outdoor pressure sensor 209; the second outdoor pressure sensor 210 includes pipelines through which the check valves 208 are connected to the first four-way valve 202A and the second four-way valve 202B, respectively, and detects the pressure of the refrigerant flowing out of the compressor 201. Typically, the first outdoor pressure sensor 209 may be a low pressure sensor and the second outdoor pressure sensor 210 may be a high pressure sensor.

Based on the above embodiments, in some embodiments, one end of the outdoor heat exchanger 203 is connected to the compressor 201 through the first four-way valve 202A and the second four-way valve 202B, and the other end is connected to the refrigerant recovery device 400. The outdoor heat exchanger 203 exchanges heat between the refrigerant flowing through the heat transfer tubes of the outdoor heat exchanger 203 and the outdoor air. The compressor 201 is disposed between the indoor heat exchanger and the outdoor heat exchanger 203, and is configured to provide power for refrigerant circulation. Taking a refrigeration cycle as an example, the compressor 201 sends a compressed refrigerant to the outdoor heat exchanger 203 via the first four-way valve 202A and the second four-way valve 202B.

Alternatively, the compressor 201 may be a variable capacity inverter compressor 201 controlled based on the rotation speed of an inverter.

In still other embodiments, the outdoor unit 200 further includes an outdoor fan 215, and the outdoor fan 215 generates an airflow of the outdoor air passing through the outdoor heat exchanger 203 to promote heat exchange between the refrigerant flowing in the heat transfer pipes of the outdoor heat exchanger 203 and the outdoor air.

In some other embodiments, the outdoor unit 200 further comprises an outdoor fan 215 motor (not shown) connected to the outdoor fan 215 for driving or changing the rotation speed of the outdoor fan 215.

In still other embodiments, the outdoor unit 200 further includes a high pressure switch (not shown), and the high pressure switch is electrically connected to the controller, and is configured to monitor the pressure of the pipeline of the multi-split air conditioning system 100, and send an abnormal message when the pressure of the pipeline of the multi-split air conditioning system 100 is abnormal, so as to control the system to be shut down and ensure normal operation of the multi-split air conditioning system 100.

Based on the above embodiments, in some embodiments, the outdoor unit 200 further includes an outdoor expansion valve 204, and the outdoor expansion valve 204 is disposed on a pipeline between the second end of the outdoor heat exchanger 203 and the first solenoid valve 401; when the multi-split air conditioning system 100 is in the second refrigerant recovery mode, the outdoor expansion valve 204 is at the maximum opening value. In this way, when the multi-split air-conditioning system 100 operates in the second refrigerant recovery mode, the outdoor expansion valve 204 is controlled to be at the maximum opening value, so that the refrigerant in the pipeline communicated with the outdoor expansion valve 204 is more quickly recovered to the refrigerant recovery device 400 through the outdoor unit 200 and the indoor unit, thereby increasing 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 100.

Indoor unit 300

The indoor unit 300 of the multi-split air conditioning system 100 includes a plurality of indoor units, for example, two indoor units (e.g., a first indoor unit 300A and a second indoor unit 300B in fig. 1) in the embodiment of the present application. Each indoor unit includes an indoor heat exchanger, a first indoor expansion valve, and a second indoor expansion valve. And the first end of the indoor heat exchanger is respectively connected with the second end of the first indoor expansion valve and the second end of the second indoor expansion valve. For each indoor unit, a first end of a first indoor expansion valve is connected to a first end of first four-way valve 202A and a first end of second four-way valve 202B via a first conduit. Illustratively, the first pipe is (14B) → (15B) → (16B) → (17B) → (18B) shown in fig. 1. For each indoor unit, a first end of the second indoor expansion valve is connected to a third end of second four-way valve 202B via a second conduit. Illustratively, the second pipe is (14A) → (15A) → (16A) → (17A) → (18A) shown in fig. 1.

In some embodiments, the indoor unit 300 further includes an indoor refrigerant leakage detection device corresponding to the indoor units one to one. The indoor refrigerant leakage detection device (not shown) is used for detecting whether the refrigerant of the indoor unit 300 corresponding to the indoor unit leaks. The refrigerant leakage detecting device is generally referred to as a refrigerant leakage detecting sensor. The detection result of the indoor refrigerant leakage detection device is used for indicating whether the indoor unit where the refrigerant leakage detection device is located leaks the refrigerant or not; determining whether an indoor unit with refrigerant leakage exists in the indoor unit set according to the detection result of each indoor refrigerant leakage detection device; and if so, controlling the multi-split air conditioning system to operate in a first refrigerant recovery mode.

Illustratively, the first indoor unit 300A includes: a first indoor heat exchanger 301A, a third indoor expansion valve 302A of the first indoor unit, and a first indoor refrigerant leakage detection device.

In some embodiments, the first indoor unit 300A further includes a first indoor fluid line temperature sensor, a first indoor return air temperature sensor, and a first indoor fan 303A.

In another example, the second indoor unit 300B includes: a second indoor heat exchanger 301B, a second indoor expansion valve, and a second indoor refrigerant leakage detection device.

In some embodiments, the second indoor unit 300B further includes a second indoor liquid pipe temperature sensor (not shown), a second indoor return air temperature sensor (not shown), and a second indoor fan 303B. The second indoor liquid pipe temperature sensor is used for detecting the temperature of a refrigerant of an indoor unit pipeline; the second indoor return air temperature sensor is used for detecting the return air temperature of the indoor unit.

In some embodiments, the first indoor heat exchanger 301A is configured to exchange heat between the refrigerant flowing through the heat transfer tubes of the first indoor heat exchanger 301A and the indoor air.

In some embodiments, the third indoor expansion valve is disposed between the first indoor heat exchanger 301A and the refrigerant recovery device 400, and has a function of expanding and decompressing the refrigerant flowing through the third indoor expansion valve, and may be used to adjust the supply amount of the refrigerant in the pipeline.

Alternatively, the multi-split air conditioning system 100 may be provided with a plurality of third indoor expansion valves, such as a plurality of electronic expansion valves. When the opening degree of the third indoor expansion valve is decreased, the flow path resistance of the refrigerant passing through the third indoor expansion valve is increased. When the opening degree of the third indoor expansion valve is increased, the flow path resistance of the refrigerant passing through the third indoor expansion valve is decreased. In this way, even if the state of other components in the circuit does not change, the flow rate of the refrigerant flowing through the first indoor heat exchanger 301A or the outdoor heat exchanger 203 changes when the opening degree of the third indoor expansion valve changes.

It should be noted that the number of indoor expansion valves and the number of outdoor expansion valves 204 shown in fig. 1 are merely examples, and the present application is not limited to this.

Optionally, the third indoor expansion valve is disposed in a pipeline between the second solenoid valve 402 and the second end of the indoor heat exchanger (e.g., the first indoor heat exchanger 301A or the second indoor heat exchanger 301B); when the multi-split air conditioning system 100 is in the first refrigerant recovery mode, the third indoor expansion valve in the indoor unit, in which refrigerant leakage occurs, is in a closed state.

In this way, the first end of each third indoor expansion valve is communicated with the second end of the corresponding indoor heat exchanger through a pipeline, when the multi-split air-conditioning system 100 is in the first refrigerant recovery mode, the third indoor expansion valve of the indoor unit where refrigerant leakage occurs is controlled to be closed, so that the refrigerant is prevented from continuously entering the indoor unit where the refrigerant leakage occurs, the refrigerant in the indoor unit where the refrigerant leakage occurs is prevented from leaking into an indoor environment, and the safe use of the multi-split air-conditioning system 100 by a user is further ensured.

In some embodiments, the first indoor fan 303A generates an airflow of the indoor air passing through the first indoor heat exchanger 301A to promote heat exchange between the refrigerant flowing in the heat transfer pipes of the first indoor heat exchanger 301A and the indoor air.

In some embodiments, the first indoor unit 300A further includes an indoor fan motor (not shown) connected to the indoor fan for driving or changing the rotation speed of the indoor fan.

In some embodiments, the first indoor unit 300A further includes a plurality of capillary tubes (not shown) for reducing the pressure of the refrigerant in the pipes, and for depressurizing the high-pressure refrigerant delivered from the condenser and delivering the depressurized refrigerant to the evaporator.

In some embodiments, the first indoor unit 300A further includes a humidity sensor (not shown) for detecting the relative humidity of the indoor air.

In some embodiments, the first indoor unit 300A further includes a dew point meter (not shown) for detecting an ambient dew point temperature near the indoor heat exchanger.

In some embodiments, the first indoor unit 300A further includes a display (not shown). The display is electrically connected to the controller. Alternatively, a display may be used to display a control panel of the multi-split air conditioning system 100, for example, the display may be used to display an indoor temperature or a current operation mode. Optionally, a display is connected to the controller, and a user can perform operations on the control panel through the display to set a program. Optionally, the display further includes a pressure sensor or a temperature sensor, and the display may transmit a user instruction to the control to implement a human-computer interaction function according to a gesture operation of the user, such as pressing a key or the like. Alternatively, the display may be a liquid crystal display, an organic light-emitting diode (OLED) display. The particular type, size, resolution, etc. of the display are not limiting, and those skilled in the art will appreciate that the display may be modified in its performance and configuration as desired.

It should be noted that the number of the indoor units is only an example, the number of the indoor units of the multi-split air conditioning system 100 shown in the present application may be two or more, and each indoor unit may be in a cooling operation or a heating operation according to actual requirements, which is not limited in the present application.

Refrigerant recovery device 400

As shown in fig. 1, the refrigerant recovery device 400 includes a first solenoid valve 401, a first expansion valve 411, a third solenoid valve 403, and a reservoir tank 404. A second end of the outdoor heat exchanger 203 is connected to a first opening of the liquid storage tank 404 through a first solenoid valve 401, and is connected to a second end of an indoor heat exchanger in each indoor unit through a third solenoid valve 403 (for example, a second end of the first indoor heat exchanger 301A and a second end of the second indoor heat exchanger 301B in fig. 1), and a third opening of the liquid storage tank 404 is respectively communicated with the first pipeline and the second pipeline through a first expansion valve 411.

It should be noted that the number of the electromagnetic valves disposed in the refrigerant recovery device 400 may be specifically set according to specific requirements, and the application is not specifically limited herein. In some embodiments, as shown in fig. 1, the refrigerant recovery device 400 further includes a second solenoid valve 402; the second opening of the liquid storage tank 404 is connected to the second end of the indoor heat exchanger in each indoor unit through a second solenoid valve 402. In this way, the first end of the second solenoid valve 402 is connected to the second opening of the liquid storage tank 404 through a pipeline, and the second end of the second solenoid valve 402 is connected to the second end of the indoor heat exchanger of each indoor unit through a pipeline, so as to form a branch for the refrigerant to flow to the liquid storage tank 404, so as to recover the refrigerant leaking from the outdoor unit 200 in the multi-split air conditioning system 100.

In another embodiment, the refrigerant recovery device 400 further includes a fourth solenoid valve 405A and a fifth solenoid valve 405B, the fourth solenoid valve 405A is disposed on a first pipe between a first end of the first four-way valve 202A and a first end of an indoor heat exchanger in each indoor unit, and the fifth solenoid valve 405B is disposed on a second pipe between a third end of the second four-way valve 202B and a first end of an indoor heat exchanger in each indoor unit.

Based on this, the on-off state of the refrigerant on the pipeline between the first end of the first four-way valve 202A and the first end of the indoor heat exchanger in each indoor unit is controlled by the fourth electromagnetic valve 405A, and the on-off state of the refrigerant on the pipeline between the third end of the second four-way valve 202B and the first end of the indoor heat exchanger in each indoor unit is controlled by the fifth electromagnetic valve 405B, so that the control of the refrigerant in the pipeline is more detailed and reasonable.

The independence between the refrigerant recovery device 400 and the outdoor unit 200 can be ensured by closing the first solenoid valve 401, the second solenoid valve 402, the third solenoid valve 403, the fourth solenoid valve 405A, and the fifth solenoid valve 405B.

For example, when the multi-split air conditioning system 100 is in the first refrigerant recovery mode, both the fourth electromagnetic valve 405A and the fifth electromagnetic valve 405B are in an open state; when the multi-split air conditioning system 100 is in the second refrigerant recovery mode, both the fourth electromagnetic valve 405A and the fifth electromagnetic valve 405B are in an open state. Therefore, when the multi-split air conditioning system 100 operates in any one of the first refrigerant recovery mode and the second refrigerant recovery mode, the fourth electromagnetic valve 405A and the fifth electromagnetic valve 405B are controlled to be in an open state, so that the refrigerant can circulate in the corresponding pipeline.

In still other embodiments, the refrigerant recovery device 400 further includes a sixth solenoid valve 406A and a seventh solenoid valve 406B. The sixth electromagnetic valve 406A is disposed on the first pipeline between the fourth electromagnetic valve 405A and the first end of the indoor heat exchanger in each indoor unit; a seventh solenoid valve 406B is provided on the second pipe between the fifth solenoid valve 405B and the first end of the indoor heat exchanger in each indoor unit.

In this way, the on-off state of the refrigerant on the first pipe between the fourth solenoid valve 405A and the first end of the indoor heat exchanger in each indoor unit is controlled by the sixth solenoid valve 406A, and the on-off state of the refrigerant on the second pipe between the fifth solenoid valve 405B and the first end of the indoor heat exchanger in each indoor unit is controlled by the seventh solenoid valve 406B.

For example, when the multi-split air conditioning system 100 is in the cooling mode, the heating mode, the first refrigerant recovery mode, or the second refrigerant recovery mode, the sixth solenoid valve 406A and the seventh solenoid valve 406B are in an open state.

For example, in the first refrigerant recovery mode or the second refrigerant recovery mode, the sixth solenoid valve 406A and the seventh solenoid valve 406B are controlled to be closed when the refrigerant recovery stop condition is satisfied.

It should be noted that the independence between the refrigerant recovery device 400 and the indoor unit 300 can be ensured by closing all of the first solenoid valve 401, the second solenoid valve 402, the third solenoid valve 403, the sixth solenoid valve 406A, and the seventh solenoid valve 406B.

Therefore, when the multi-split air conditioning system 100 operates in any one of a cooling mode, a heating mode, a first refrigerant recovery mode or a second refrigerant recovery mode, the sixth electromagnetic valve 406A and the seventh electromagnetic valve 406B are controlled to be in an open state, so that the refrigerant can circulate in the corresponding pipelines. After the refrigerant recovery is completed, that is, when the refrigerant recovery stop condition is satisfied, the sixth electromagnetic valve 406A and the seventh electromagnetic valve 406B are controlled to be closed, so that the indoor units in the indoor unit 300, which have refrigerant leakage, are freely separated from the refrigerant recovery device 400 and the outdoor unit 200, and thus the indoor units, which have refrigerant leakage, are not affected by the refrigerant recovery device 400 and the outdoor unit 200 during the replacement process, and the convenience of installing or replacing the indoor units is improved.

Referring to fig. 1, as shown in fig. 2 and fig. 3, in some embodiments, the refrigerant recovery device 400 further includes a second expansion valve 412, so as to solve the problem that in the refrigerant recovery process, when the amount of refrigerant circulating in the multi-split air-conditioning system is smaller and smaller, and the low pressure of the multi-split air-conditioning system is closer and closer to a preset pressure range (generally, the atmospheric pressure of the environment where the multi-split air-conditioning system is located), the discharge temperature of the compressor is higher and higher, which results in low reliability of the compressor.

As shown in fig. 2, a first end of the second expansion valve 412 is connected to a fourth opening of the reservoir tank 404, a second end of the second expansion valve 412 is respectively communicated with a third pipeline and a fourth pipeline, the third pipeline is a pipeline between the fourth solenoid valve 405A and the sixth solenoid valve 406A, the fourth pipeline is a pipeline between the fifth solenoid valve 405B and the seventh solenoid valve 406B, and exemplarily, the third pipeline is a pipeline (16B) shown in fig. 2, and the fourth pipeline is a pipeline (16B) shown in fig. 2.

As shown in fig. 3, a first end of the second expansion valve 412 is in communication with a fifth pipeline, a second end of the second expansion valve is in communication with a third pipeline and a fourth pipeline, respectively, and the fifth pipeline is a pipeline between the first solenoid valve 401 and the first opening of the reservoir tank 404.

Based on the above-mentioned two setting manners of the second expansion valve 412 as shown in fig. 2 and fig. 3, a second expansion valve 412 may be added between the fourth opening of the liquid storage tank 404 and the third pipeline and between the fourth opening of the liquid storage tank 404 and the fourth pipeline, or a second expansion valve 412 may be added between the fifth pipeline and the third pipeline and between the fifth pipeline and the fourth pipeline, so that in the refrigerant recovery process, the second expansion valve 412 is opened to allow a part of the refrigerant to bypass the compressor 201, thereby reducing the exhaust temperature of the compressor 201, and achieving the purpose of reducing the temperature of the compressor 201, thereby ensuring the reliability of the compressor 201 in the refrigerant recovery process.

In addition, in the refrigerant recovery process, the refrigerant entering the receiver 404 may be a gas-phase refrigerant and a liquid-phase refrigerant, and in the case that the refrigerant entering the receiver 404 is a two-phase refrigerant, since the average density of the two-phase refrigerant is low, the amount of the refrigerant stored in the receiver 404 is reduced, thereby affecting the refrigerant recovery effect. Therefore, in the refrigerant recovery process, the second expansion valve 412 is opened to bypass the gaseous refrigerant to enter, so as to improve the refrigerant recovery effect.

The above-described installation mode (1) of the second expansion valve 412 is applied to the first refrigerant recovery mode. The above-described installation manner (2) of the second expansion valve 412 is applicable to both the first refrigerant recovery mode and the second refrigerant recovery mode. Of course, the two modes can also be combined for use and are specifically started according to specific conditions. The present application does not specifically limit the manner in which the second expansion valve 412 is disposed.

In addition, the arrangement of the second expansion valve 412 in fig. 2 or fig. 3 can be used for improving the refrigerant recovery device 400 in fig. 4 and fig. 5 in the following figures.

Based on the above embodiment, referring to fig. 1, as shown in fig. 4, the refrigerant recovery device 400 further includes a first supercooling heat exchanger 413, where the first supercooling heat exchanger 413 includes a first passage 416 and a second passage 417; a third opening of the liquid storage tank 404 is respectively communicated with the first pipeline and the second pipeline through a first channel of the second expansion valve 412 and the first supercooling heat exchanger 413 in sequence; a first end of the third solenoid valve 403 is connected to a second end of the outdoor heat exchanger 203 through a second passage of the first supercooling heat exchanger 413.

Based on the first supercooling heat exchanger 413, the refrigerant flow recovered in the refrigerant recovery device 400 passes through the first passage 416 of the first cold heat exchanger 413, and the refrigerant flow passes through the second passage 417 of the first cold heat exchanger 413 during the operation of the multi-split air conditioning system 100. The second channel 417 cools the refrigerant flowing through the second channel 417 to release corresponding heat. The first passage 416 heats the recovered refrigerant flowing through the first passage 416 by using the heat released from the second passage 417, so that the liquid refrigerant in the recovered refrigerant in two phases (gas and liquid) is converted into a gas refrigerant, the content of the liquid refrigerant in the refrigerant released by the refrigerant recovery device 400 is reduced, and the content of the gas refrigerant in the released recovered refrigerant is increased, thereby ensuring the use efficiency of the recovered refrigerant.

In addition, in the process of releasing the recovered refrigerant in the synchronous refrigeration operation mode of the multi-split air conditioning system 100, the refrigerant recovery device 400 releases the recovered refrigerant to the compressor 203 of the outdoor unit 200, so that the content of the liquid refrigerant in the refrigerant released by the refrigerant recovery device 400 is reduced, the liquid return of the compressor 201 is reduced, and the service life of the compressor 201 is prolonged.

In other embodiments, the refrigerant recovery device 400 further includes a first temperature sensor (not shown in fig. 4). Illustratively, the first temperature sensor is disposed on the (22) line as shown in FIG. 4. The first temperature sensor is used to detect a temperature value of the refrigerant flowing out of the first passage 416 of the first supercooling heat exchanger 413.

Referring to fig. 5 in conjunction with fig. 1, in some embodiments, the refrigerant recovery device 400 further includes a throttling device 414 and a second subcooling heat exchanger 415. Wherein the second subcooling heat exchanger 415 comprises a third pass 418 and a fourth pass 419; a third opening of the liquid storage tank is also communicated with the first pipeline through a throttling device and a third channel 418 of the second supercooling heat exchanger in sequence; and the second end of the third electromagnetic valve is connected with the indoor expansion valve through a fourth passage 419 of the second supercooling heat exchanger.

Based on the throttling device 414 and the second supercooling heat exchanger 415, the refrigerant recovered in the refrigerant recovery device 400 is throttled by the throttling device and then flows through the third channel 418 of the second supercooling heat exchanger 415; the refrigerant flow passes through the fourth passage 419 of the second cold heat exchanger 415 during operation of the multi-split air conditioning system 100. The fourth passage 419 cools the refrigerant flowing through the fourth passage 419 to release corresponding heat. The third channel 418 heats the recovered refrigerant flowing through the third channel 418 by using the heat released by the fourth channel 419, so that the liquid refrigerant in the two-phase (gas and liquid) recovered refrigerant is converted into a gas refrigerant, the content of the liquid refrigerant in the refrigerant released by the refrigerant recovery device 400 is reduced, the content of the gas refrigerant in the released recovered refrigerant is increased, and the use efficiency of the recovered refrigerant is ensured.

In some embodiments, the refrigerant recovery device 400 further includes a second temperature sensor (not shown) for detecting a temperature value of the refrigerant flowing out of the third channel 418 of the second subcooling heat exchanger 415.

Based on above-mentioned first temperature sensor, can realize carrying out reasonable control to the aperture of first expansion valve. Exemplarily, step S11 to step S13 in the following flowchart 6.

And S11, when the multi-split air conditioning system operates in a refrigerant release mode, acquiring a first temperature value detected by a first temperature sensor and a pressure value detected by a first outdoor pressure sensor.

And S12, if the difference value between the first temperature value and the second temperature value is greater than or equal to a first preset temperature value, controlling the first expansion valve to increase the opening degree.

And the second temperature value is a saturation temperature value corresponding to the pressure value detected by the first outdoor pressure sensor.

And S13, if the difference value between the first temperature value and the second temperature value is greater than a first preset temperature value, controlling the first expansion valve to reduce the opening degree.

In this example, 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 supercooling 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. And controlling the opening degree of the first expansion valve based on the size relation between the temperature difference value and the first preset temperature value so as to ensure that the opening degree of the first expansion valve is in a reasonable range, thereby ensuring that the quantity of the refrigerant released by the refrigerant recovery device is in a reasonable range. On one hand, the problem that the multi-split air-conditioning system cannot process the refrigerant timely due to too much refrigerant in the pipeline of the whole multi-split air-conditioning system caused by too much refrigerant released by the refrigerant recovery device is avoided; on the other hand, the problem that the refrigerant quantity released by the refrigerant recovery device is too small, so that the refrigerant quantity in the pipeline of the whole multi-split air-conditioning system is too small, and the working efficiency of the multi-split air-conditioning system is reduced, such as the cooling speed or the heating speed is reduced, is avoided. Based on the throttling device 414 and the second cold heat exchanger 415 shown in fig. 5, the refrigerant recovered in the refrigerant recovery device is throttled by the throttling device 414 and then flows through the third channel 418 of the second supercooling heat exchanger 415; during operation of the multi-split air conditioning system, the refrigerant flows through the fourth passage 419 of the second cooling heat exchanger 415. The fourth passage cools the refrigerant flowing through the fourth passage 419 to release corresponding heat. The third channel 418 heats the recovered refrigerant flowing through the third channel 418 by using the heat released by the fourth channel 419, so that the liquid refrigerant in the recovered refrigerant in two-phase state (gas state and liquid state) is converted into the gas refrigerant, the content of the liquid refrigerant in the refrigerant released by the refrigerant recovery device is reduced, the content of the gas refrigerant in the released recovered refrigerant is improved, and the use efficiency of the recovered refrigerant is ensured.

Based on the second temperature sensor in the above embodiment, the releasing process of the refrigerant in the refrigerant recovery device 400 can be reasonably controlled.

Exemplarily, steps S21 to S23 in the following flowchart 7.

And S21, when the multi-split air-conditioning system operates in a refrigerant release mode, acquiring a third temperature value detected by the second temperature sensor and a pressure value detected by the first outdoor pressure sensor.

In step S22, if the difference between the third temperature value and the second temperature value is greater than or equal to a second preset temperature value, the operation of the refrigerant releasing mode is ended.

And step S23, if the difference value between the third temperature value and the second temperature value is smaller than a second preset temperature value, continuing to operate the refrigerant releasing mode.

It should be noted that the second preset temperature value is a very small value.

In this example, the temperature difference between the first temperature value and the saturation temperature value is obtained by comparing a first temperature value of the refrigerant flowing out of the third channel 418 of the second supercooling heat exchanger 415 with the saturation temperature corresponding to the pressure value of the refrigerant at the inlet of the gas-liquid separator, that is, a second temperature value. The releasing process of the refrigerant recovery device is reasonably controlled based on the size relation between the temperature difference value and the second preset temperature value, so that the refrigerant recovery device 400 can release the refrigerant under the condition of sufficient refrigerant, the refrigerant releasing mode is still executed under the condition that no refrigerant exists in the refrigerant recovery device, the refrigerant quantity in the multi-split air-conditioning system is small, and the working efficiency of the multi-split air-conditioning system is reduced. In addition, it should be noted that the number of the electromagnetic valves and the number of the stop valves provided in the multi-split air conditioning system 100 in fig. 1 to 5 may be according to specific requirements.

In some embodiments, the refrigerant recovery device 400 further includes a first stop valve 407A, a second stop valve 407B, a third stop valve 408A, a fourth stop valve 408B, a fifth stop valve 409, and a sixth stop valve 410.

First stop valve 407A is disposed on a pipeline between fourth solenoid valve 405A and a first end of first four-way valve 202A, a first end of first stop valve 407A is connected to a first end of first four-way valve 202A via a pipeline, and a second end of first stop valve 407A is connected to a first end of fourth solenoid valve 405A via a pipeline.

Second stop valve 407B is provided in a connection pipe between fifth solenoid valve 405B and the third end of second four-way valve 202B, a first end of second stop valve 407B is connected to the third end of second four-way valve 202B via a pipe, and a second end of second stop valve 407B is connected to the first end of fifth solenoid valve 405B via a pipe.

The third cut-off valve 408A is disposed on a pipeline between the sixth solenoid valve 406A and the first end of the indoor heat exchanger in each indoor unit, the first end of the third cut-off valve 408A is connected to the second end of the sixth solenoid valve 406A through a pipeline, the second end of the third cut-off valve 408A is connected to the first end of the first indoor expansion valve of each indoor unit through a pipeline, the second end of the first indoor expansion valve is connected to the first end of the indoor heat exchanger of the corresponding indoor unit through a pipeline, and the second end of the fourth solenoid valve 405A is connected to the first end of the sixth solenoid valve 406A through a pipeline; a second end of the fifth solenoid valve 405B is connected to a first end of a seventh solenoid valve 406B via a conduit.

The fourth cut-off valve 408B is disposed on a pipeline between the seventh solenoid valve 406B and the first end of the indoor heat exchanger in each indoor unit, the first end of the fourth cut-off valve 408B is connected to the second end of the seventh solenoid valve 406B through a pipeline, the second end of the fourth cut-off valve 408B is connected to the first end of the second indoor expansion valve of each indoor unit through a pipeline, and the second end of the second indoor expansion valve is connected to the first end of the indoor heat exchanger of the corresponding indoor unit.

The fifth stop valve 409 is disposed on a connection pipeline between the second end of the outdoor heat exchanger 203 and the first electromagnetic valve 401, the first end of the fifth stop valve 409 is connected to the second end of the outdoor heat exchanger 203 through a pipeline, the second end of the fifth stop valve 409 is connected to the first end of the first electromagnetic valve 401 through a pipeline, and the second end of the first electromagnetic valve 401 is connected to the first opening of the liquid storage tank 404 through a pipeline.

The sixth cut-off valve 410 is disposed on a connection pipeline between the third electromagnetic valve 403 and the second end of the indoor heat exchanger in each indoor unit, a first end of the sixth cut-off valve 410 is connected to the second end of the third electromagnetic valve 403, a second end of the sixth cut-off valve 410 is connected to the second end of the third indoor expansion valve in each indoor unit, and a first end of the third indoor expansion valve in each indoor unit is connected to the second end of the indoor heat exchanger in each indoor unit.

Based on the first to sixth stop valves 407A to 410, the first, second, third, fourth, fifth and

sixth stop valves

407A, 407B, 408A, 408B, 409 and 410 are in an open state during the operation of the multi-split air conditioning system 100 in the first refrigerant recovery mode or the second refrigerant recovery mode. After the first refrigerant recovery mode or the second refrigerant recovery mode is completed, the first solenoid valve 401, the second solenoid valve 402, the third solenoid valve 403, the fourth solenoid valve 405A, the fifth solenoid valve 405B, the sixth solenoid valve 406A, and the seventh solenoid valve 406B are in a closed state, and the first stop valve 407A, the second stop valve 407B, the third stop valve 408A, the fourth stop valve 408B, the fifth stop valve 409, and the sixth stop valve 410 are in a closed state, so as to better prevent the refrigerant from flowing through the pipeline corresponding to the stop valves.

In other embodiments, the outdoor unit 200 further includes a seventh cut-off valve 211A, an eighth cut-off valve 211B, and a ninth cut-off valve 212; the seventh stop valve 211A is disposed on a pipeline between the first stop valve 407A and the first end of the first four-way valve 202A, the first end of the seventh stop valve 211A is connected to the first end of the first four-way valve 202A, and the second end of the seventh stop valve 211A is connected to the first end of the first stop valve 407A; an eighth cut-off valve 211B is provided in a connection pipe between second cut-off valve 407B and the third end of second four-way valve 202B, a first end of eighth cut-off valve 211B is connected to the third end of second four-way valve 202B, and a second end of eighth cut-off valve 211B is connected to the first end of second cut-off valve 407B; the ninth cut-off valve 212 is disposed on a connection pipe between the second end of the outdoor heat exchanger 203 and the first end of the first solenoid valve 401, the first end of the ninth cut-off valve 212 is connected to the second end of the outdoor heat exchanger 203, and the second end of the ninth cut-off valve 212 is connected to the first end of the fifth cut-off valve 409.

Based on the seventh stop valve 211A, the eighth stop valve 211B, and the ninth stop valve 212, when the air conditioner is in the cooling mode, the heating mode, the first refrigerant recovery mode, or the second refrigerant recovery mode, the seventh stop valve 211A, the eighth stop valve 211B, and the ninth stop valve 212 are controlled to be in the open state, so as to ensure that the refrigerant circulates in the pipeline. After the refrigerant is recovered, the seventh stop valve 211A, the eighth stop valve 211B and the ninth stop valve 212 are controlled to be closed, so that the outdoor unit 200 is freely separated from the refrigerant recovery device 400 and the indoor unit 300, the outdoor process is not affected by the refrigerant recovery device 400 and the indoor unit 300, and the convenience of installing or replacing the outdoor unit 200 is improved.

In still other embodiments, the outdoor unit 200 further includes an eighth solenoid valve 213A, a ninth solenoid valve 213B, and a tenth solenoid valve 214; a first end of eighth solenoid valve 213A is connected to a first end of first four-way valve 202A, and a second end of eighth solenoid valve 213A is connected to a first end of seventh stop valve 211A; a first end of ninth solenoid valve 213B is connected to a third end of second four-way valve 202B, and a second end of ninth solenoid valve 213B is connected to a first end of eighth stop valve 211B; a first end of the tenth solenoid valve 214 is connected to the second end of the outdoor heat exchanger 203, and a second end of the tenth solenoid valve 214 is connected to a first end of the ninth cutoff valve 212.

Based on the eighth solenoid valve 213A, the ninth solenoid valve 213B and the tenth solenoid valve 214, when the air conditioner is in the cooling mode, the heating mode, the first refrigerant recovery mode or the second refrigerant recovery mode, the eighth solenoid valve 213A, the ninth solenoid valve 213B and the tenth solenoid valve 214 are controlled to be in the open state, so as to ensure that the refrigerant circulates in the pipeline. After the refrigerant is recovered, the eighth solenoid valve 213A, the ninth solenoid valve 213B, and the tenth solenoid valve 214 are all controlled to be in a closed state, so that the outdoor unit 200 is freely separated from the refrigerant recovery device 400 and the indoor unit 300, and thus the outdoor unit 200 is not affected by the refrigerant recovery device 400 and the indoor unit 300 during the outdoor replacement process, and the convenience of installing or replacing the outdoor unit 200 is improved.

For example, in conjunction with fig. 1 to 5, three shut-off valves may be further provided at three ends of the indoor unit 300, respectively, that is, one shut-off valve is provided at one end of the indoor unit 300 communicating with the first end of the first four-way valve 202A and the first end of the second four-way valve 202B, that is, a shut-off valve is provided on the pipeline (14B) shown in fig. 1 to 3, and a tenth shut-off valve is provided in fig. 4; another shutoff valve is provided at one end of the indoor unit 300 communicating with the third end of the second four-way valve 202B, that is, a shutoff valve is provided on the line (14A) shown in fig. 1 to 3, and an eleventh shutoff valve is provided in fig. 4; another stop valve is disposed at one end of the indoor unit 300 and the refrigerant recovery device 400, that is, the stop valve is disposed on the pipeline (9) as shown in fig. 1 to 3. The tenth and eleventh cut-off valves are closed, so that the indoor unit 300 and the refrigerant recovery device 400 are relatively independent, and the indoor units in the indoor unit 300 can be conveniently replaced.

As still another example, as the thirteenth cut-off valve 308A and the fourteenth cut-off valve 308B provided in fig. 1 to 5, the first indoor expansion valve 304A of the first indoor unit and the second indoor expansion valve 305A of the first indoor unit are further controlled by the thirteenth cut-off valve 308A; the first indoor expansion valve 304B of the second indoor unit and the second indoor expansion valve of the second indoor unit 300B are further controlled by the fourteenth stop valve 308B.

In some embodiments, the multi-split air conditioning system 100 has at least one or more of the following operation modes: the system comprises a synchronous refrigeration mode, a synchronous heating mode, a first asynchronous refrigeration and heating mode, a second asynchronous refrigeration and heating mode, a first refrigerant recovery mode and a second refrigerant recovery mode. In any mode of the first asynchronous refrigeration and heating mode and the second asynchronous refrigeration and heating mode, at least one indoor unit in heating operation and at least one indoor unit in refrigeration operation can exist in the indoor unit.

With reference to the above embodiments, the multi-split air conditioning system 100 at least has one or more of the following operation modes: the system comprises a synchronous refrigeration mode, a synchronous heating mode, a first asynchronous refrigeration and heating mode, a second asynchronous refrigeration and heating mode, a first refrigerant recovery mode, a second refrigerant recovery mode and a refrigerant release mode.

The above operation modes are described in detail below. For convenience of understanding, the first indoor unit 300A is operated as cooling to lower the indoor temperature, and the second indoor unit 300B is operated as heating to raise the indoor temperature.

1. Synchronous cooling mode

When the multi-split air conditioning system 100 is in the synchronous cooling mode, the outdoor heat exchanger 203 operates as a condenser, each indoor heat exchanger operates as an evaporator, 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, the first expansion valve 411 is in a closed state, and the first indoor expansion valve of each indoor unit and the second indoor expansion valve of each indoor unit are in an open state.

In some embodiments, first four-way valve 202A and second four-way valve 202B may each be a four-way reversing valve.

The operation cycle of the synchronous cooling mode of the air conditioning system will be described in detail, taking as an example that both the first indoor unit 300A and the second indoor unit 300B are indoor units requiring cooling. Referring to FIG. 1, as shown in FIG. 8, a D port of first four-way valve 202A is connected to a C port, an E port is connected to an S port, a D port of second four-way valve 202B is connected to a C port, and an E port is connected to an S port; the first solenoid valve 401 is closed, the second solenoid valve 402 is closed, the third solenoid valve 403 is open, the fourth solenoid valve 405A is open, the fifth solenoid valve 405B is open, both the first indoor expansion valve 304A of the first indoor unit and the first indoor expansion valve 304B of the second indoor unit are open, the first expansion valve 411 is closed, both the second indoor expansion valve 305A of the first indoor unit and the second indoor expansion valve of the second indoor unit 300B are open, and all other solenoid valves, other indoor expansion valves, other outdoor expansion valves 204, other expansion valves, and other shutoff valves are open in the multi-split air conditioning system 100 shown in fig. 8.

As shown in fig. 8, the refrigerant circuit flowing through the first indoor unit 300A of the indoor unit 300 includes: (1) → (2) → (3) → (4) → (5) → (6) → (7) → (8) → (9) → (10) → (12A) → (14A) → (15A) → (16A) → (17A) → (18A) → (19) → (1), and (1) → (2) → (3) → (4) → (5) → (6) → (7) → (8) → (9) → (10) → (13A) → (14B) → (15B) → (16B) → (17B) → (18B) → (19) → (1).

As shown in fig. 8, the refrigerant circuit flowing through the second indoor unit 300B of the indoor unit 300 is: (1) → (2) → (3) → (4) → (5) → (6) → (7) → (8) → (9) → (11) → (12B) → (14A) → (15A) → (16A) → (17A) → (18A) → (19) → (1) and (1) → (2) → (3) → (4) → (5) → (6) → (7) → (8) → (9) → (11) → (13B) → (14B) → (15B) → (16B) → (17B) → (18B) → (19) → (1).

It should be noted that, (14B) → (15B) → (16B) → (17B) and (14A) → (15A) → (16A) → (17A) are merely examples, and the (14B) → (15B) → (16B) → (17B) shown in the present application may be replaced with one or more pipes, for example, the pipe (16B), that is, only the fourth electromagnetic valve 405A or the fourth electromagnetic valve 405A and the first cut-off valve 407A are provided in the pipe. The number of the electromagnetic valves and the number of the stop valves arranged on the section of pipeline are set according to specific requirements.

Specifically, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 201 enters the oil separator 206206, and the refrigerant entering the oil separator 206 is divided into two portions. Wherein, a part of the oil enters the inlet of the gas-liquid separator 205 through an oil return capillary 207; the other part of the high-temperature and high-pressure gaseous refrigerant passing through the oil separator 206 enters the outdoor heat exchanger 203 through the check valve 208 and the first four-way valve 202A. The high-temperature and high-pressure gaseous refrigerant is condensed into a medium-temperature and high-pressure liquid refrigerant in the outdoor heat exchanger 203. Further, the medium-temperature and high-pressure liquid refrigerant sequentially passes through the third solenoid valve 403 of the refrigerant recovery device 400, and is then split into two parts, one part of the medium-temperature and high-pressure liquid refrigerant flows into the third indoor expansion valve 302A of the first indoor unit 300A to form a low-temperature and low-pressure liquid refrigerant, and then flows into the first indoor heat exchanger 301A, and is evaporated into a low-temperature and low-pressure gaseous refrigerant by the first indoor heat exchanger 301A; after another part of the refrigerant flows into the second indoor expansion valve of the second indoor unit 300B to form a low-temperature low-pressure liquid refrigerant, the low-temperature low-pressure liquid refrigerant flows into the second indoor heat exchanger 301B again, and is evaporated into a low-temperature low-pressure gaseous refrigerant by the second indoor heat exchanger 301B. The low-temperature and low-pressure gaseous refrigerant evaporated by the first indoor heat exchanger 301A and the second indoor heat exchanger 301B is divided and then merged, specifically, divided: the low-temperature and low-pressure gaseous refrigerant evaporated by the first indoor heat exchanger 301A is distributed to the first indoor expansion valve 304A of the first indoor unit and the second indoor expansion valve 305A of the first indoor unit; and the low-temperature and low-pressure gaseous refrigerant evaporated by the second indoor heat exchanger 301B is distributed to the first indoor expansion valve 304B of the second indoor unit and the second indoor expansion valve of the second indoor unit 300B. And (3) converging: the low-temperature and low-pressure refrigerant flowing out through the first indoor expansion valve 304A of the first indoor unit, the low-temperature and low-pressure refrigerant flowing out through the first indoor expansion valve 304B of the second indoor unit, and the low-temperature and low-pressure refrigerant flowing out through the second indoor expansion valve 305A of the first indoor unit and the low-temperature and low-pressure refrigerant flowing out through the second indoor expansion valve of the second indoor unit 300B are combined into a second refrigerant. Further, the merged first refrigerant passes through the fourth solenoid valve 405A, and then, the merged second refrigerant passes through the fifth solenoid valve 405B and the second four-way selector valve in sequence, and then, the merged first refrigerant and the merged second refrigerant are merged again to form a low-temperature low-pressure gaseous refrigerant, and the low-temperature low-pressure gaseous refrigerant formed by the merging again enters the gas-liquid separator 205. The low-temperature and low-pressure gaseous refrigerant flowing out of the gas-liquid separator 205 enters the air return port of the compressor 201, and the low-temperature and low-pressure gaseous refrigerant is compressed into a high-temperature and high-pressure gaseous refrigerant by the compressor 201 and is discharged from the air outlet of the compressor 201, so that the synchronous refrigeration operation of the air conditioning system is completed.

2. Synchronous heating mode

When the multi-split air conditioning system 100 is in the synchronous heating mode, the outdoor heat exchanger 203 operates as an evaporator, each indoor heat exchanger operates 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, the first expansion valve 411 is in a closed state, the first indoor expansion valve of each indoor unit is in a closed state, and the second indoor expansion valve of each indoor unit is in an open state.

The operation cycle of the synchronous heating mode of the air conditioning system will be described in detail, taking as an example that both the first indoor unit 300A and the second indoor unit 300B are indoor units that require heating. With reference to fig. 1, as shown in fig. 9, an S port of first four-way valve 202A is connected to a C port, an E port is connected to a D port, an S port of second four-way valve 202B is connected to a C port, and an E port is connected to a D port; the first solenoid valve 401 is closed, the second solenoid valve 402 is closed, the third solenoid valve 403 is opened, the first expansion valve 411 is closed, the fifth solenoid valve 405B is opened, both the first indoor expansion valve 304A of the first indoor unit and the first indoor expansion valve 304B of the second indoor unit are closed, both the second indoor expansion valve 305A of the first indoor unit and the second indoor expansion valve of the second indoor unit 300B are opened, and other solenoid valves, other indoor expansion valves, other outdoor expansion valves 204, other expansion valves, and other shutoff valves in the multi-split air conditioning system 100 shown in fig. 9 are opened.

As shown in fig. 9, the refrigerant circuit flowing through the first indoor unit 300A of the indoor unit 300 includes: (1) → (2) → (18A) → (17A) → (16A) → (15A) → (14A) → (12A) → (10) → (9) → (8) → (7) → (6) → (5) → (4) → (3) → (19) → (1).

As shown in fig. 9, the refrigerant circuit flowing through the second indoor unit 300B of the indoor unit 300 is: (1) → (2) → (18A) → (17A) → (16A) → (15A) → (14A) → (12B) → (11) → (9) → (8) → (7) → (6) → (5) → (4) → (3) → (19) → (1).

Specifically, the high-temperature and 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 portions. Wherein, a part of the oil enters the inlet of the gas-liquid separator 205 through the oil return capillary 207; another part of the high-temperature and high-pressure gaseous refrigerant passing through the oil separator 206 passes through the check valve 208, the second four-way valve 202B, and the fifth solenoid valve 405B in sequence, and then is branched to pass through the second indoor expansion valve 305A of the first indoor unit, and then enters the first indoor heat exchanger 301A of the first indoor unit 300A, and is branched to pass through the second indoor expansion valve of the second indoor unit 300B, and then enters 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 high-temperature and high-pressure gas refrigerant, and condense the refrigerant into a medium-temperature and high-pressure liquid refrigerant. The liquid refrigerant of medium temperature and high pressure flowing out of the first indoor heat exchanger 301A passes through the third indoor expansion valve 302A of the first indoor unit 300A and the liquid refrigerant of medium temperature and high pressure flowing out of the second indoor heat exchanger 301B passes through the third indoor expansion valve 302B of the second indoor unit, and then are merged. The merged refrigerant passes through the third solenoid valve 403 and the outdoor expansion valve 204 in sequence, and is throttled to form a low-temperature and low-pressure liquid refrigerant. The low-temperature low-pressure liquid refrigerant is evaporated 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 and low-pressure gaseous refrigerant flowing out of the gas-liquid separator 205 enters a return air port (also called a suction port) of the compressor 201; the low-temperature low-pressure gaseous refrigerant is compressed into a high-temperature high-pressure gaseous refrigerant by the compressor 201, and is discharged from the compressor 201, so that the synchronous heating mode operation of the air conditioning system is completed.

3. First asynchronous cooling and heating mode

When the multi-split air conditioning system 100 is in the first asynchronous cooling and heating mode, the outdoor heat exchanger 203 serves as a condenser to work, all indoor heat exchangers of the first indoor units 300A included in the indoor group serve as evaporators to work, and all indoor heat exchangers of the second indoor units 300B included in the indoor group serve as condensers to work; the first indoor expansion valve 304A of the first indoor unit is in an open state, and the second indoor expansion valve 305A of the first indoor unit is in a closed state; the second indoor expansion valve of the second indoor unit 300B is in an open state, and the first indoor expansion valve 304B of the second indoor unit is in a closed state; 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 a closed state.

Taking the indoor units of which the first indoor unit 300A needs cooling and the second indoor units 300B all need heating as examples, the operation cycle of the first asynchronous cooling and heating mode of the air-conditioning system will be described in detail.

Referring to FIG. 1, as shown in FIG. 10, a D port of first four-way valve 202A is connected to a C port, an E port is connected to an S port, a D port of second four-way valve 202B is connected to an E port, and a C port is connected to an S port; the first solenoid valve 401 is closed, the second solenoid valve 402 is closed, the third solenoid valve 403 is open, the first expansion valve 411 is closed, both the first indoor expansion valve 304A of the first indoor unit and the second indoor expansion valve of the second indoor unit 300B are open, both the second indoor expansion valve 305A of the first indoor unit and the first indoor expansion valve 304B of the second indoor unit are closed, and other solenoid valves, other indoor expansion valves, other outdoor expansion valves 204, other expansion valves, and other shutoff valves in the multi-split air conditioning system 100 shown in fig. 10 are open.

As shown in fig. 10, the refrigerant circuit flowing through the first indoor unit 300A of the indoor unit 300 includes: (1) → (2) → (3) → (4) → (5) → (6) → (7) → (8) → (9) → (10) → (13A) → (14B) → (15B) → (16B) → (17B) → (18B) → (19) → (1), and (1) → (2) → (18A) → (17A) → (16A) → (15A) → (14A) → (12B) → (11) → (10) → (13A) → (14B) → (15B) → (16B) → (17B) → (18B) → (19) → (1).

As shown in fig. 10, the refrigerant circuit flowing through the second indoor unit 300B of the indoor unit 300 is: (1) → (2) → (18A) → (17A) → (16A) → (15A) → (14A) → (12B) → (11) → (10) → (13A) → (14B) → (15B) → (16B) → (17B) → (18B) → (19) → (1).

Specifically, the high-temperature and 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, and one part enters the inlet of the gas-liquid separator 205 through the oil return capillary tube 207; the other part passes through the check valve 208, and the high-temperature and high-pressure gaseous refrigerant from the oil separator 206 is divided into two parts by the check valve 208. A part of the refrigerant passing through the check valve 208 enters the outdoor heat exchanger 203 through the first four-way valve 202A, the high-temperature and high-pressure gaseous refrigerant is condensed by the outdoor heat exchanger 203 into a medium-temperature and high-pressure liquid refrigerant, and the medium-temperature and high-pressure liquid refrigerant sequentially passes through the outdoor electronic expansion valve and the third electromagnetic valve 403 of the refrigerant recovery device 400 and flows out; another part of the refrigerant passing through the check valve 208 flows out through the second four-way valve 202B, and the outflow high-temperature and high-pressure gaseous refrigerant sequentially passes through the fifth solenoid valve 405B and the second indoor expansion valve of the second indoor unit 300B, enters the second indoor heat exchanger 301B, is condensed into an intermediate-temperature and high-pressure liquid refrigerant by the second indoor heat exchanger 301B, and flows out through the second indoor expansion valve of the second indoor unit 300B. Further, the refrigerant flowing out of the second indoor expansion valve is merged with the refrigerant flowing out of the third solenoid valve 403 of the refrigerant recovery device 400, the merged refrigerant enters the first indoor heat exchanger 301A of the first indoor unit 300A and is evaporated into a low-temperature and low-pressure gaseous refrigerant, and the low-temperature and low-pressure gaseous refrigerant sequentially passes through the first indoor expansion valve 304A and the fourth solenoid valve 405A of the first indoor unit and then enters the gas-liquid separator 205; the low-temperature and low-pressure gaseous refrigerant flowing out of the gas-liquid separator 205 enters a suction port of the compressor 201; the low-temperature low-pressure gaseous refrigerant is compressed into a high-temperature high-pressure gaseous refrigerant by the compressor 201, and is discharged from the compressor 201, so that the refrigeration/heating of the air conditioning system is completed, and the operation of a refrigeration main body is completed, namely, the first asynchronous refrigeration and heating mode is completed.

4. Second asynchronous refrigerating and heating mode

When the multi-split air conditioning system 100 is in the second asynchronous cooling and heating mode, the outdoor heat exchanger 203 serves as an evaporator to work, all indoor heat exchangers of the first indoor units 300A included in the indoor group serve as evaporators to work, and all indoor heat exchangers of the second indoor units 300B included in the indoor group serve as condensers to work; the first indoor expansion valve 304A of the first indoor unit is in an open state, and the second indoor expansion valve 305A of the first indoor unit is in a closed state; the first indoor expansion valve 304B of the second indoor unit is in a closed state, and the second indoor expansion valve 305A of the first indoor unit is in an open state.

Taking the indoor units of which the first indoor unit 300A needs cooling and the second indoor units 300B all need heating as examples, the operation cycle of the second asynchronous cooling and heating mode of the air-conditioning system will be described in detail. With reference to fig. 1, as shown in fig. 11, a D port of first four-way valve 202A is connected to an E port, a C port is connected to an S port, a D port of second four-way valve 202B is connected to an E port, and a C port is connected to an S port; the first solenoid valve 401 is closed, the second solenoid valve 402 is closed, the third solenoid valve 403 is open, the first expansion valve 411 is closed, the fourth solenoid valve 405A is open, the fifth solenoid valve 405B is open, both the first indoor expansion valve 304A of the first indoor unit and the second indoor expansion valve of the second indoor unit 300B are open, both the second indoor expansion valve 305A of the first indoor unit and the first indoor expansion valve 304B of the second indoor unit are closed, and all other solenoid valves, other indoor expansion valves, other outdoor expansion valves 204, other expansion valves, and other shutoff valves are open in the multi-split air conditioning system 100 shown in fig. 11.

As shown in fig. 11, the refrigerant circuit flowing through the first indoor unit 300A of the indoor unit 300 includes: (1) → (2) → (18A) → (17A) → (16A) → (15A) → (14A) → (12B) → (11) → (10) → (13A) → (14B) → (15B) → (16B) → (17B) → (18B) → (19) → (1).

As shown in fig. 11, the refrigerant circuit flowing through the second indoor unit 300B of the indoor unit 300 is: (1) → (2) → (18A) → (17A) → (16A) → (15A) → (14A) → (12B) → (11) → (9) → (8) → (7) → (6) → (5) → (4) → (3) → (19) → (1); and, (1) → (2) → (18A) → (17A) → (16A) → (15A) → (14A) → (12B) → (11) → (10) → (13A) → (14B) → (15B) → (16B) → (17B) → (18B) → (19) → (1).

Specifically, the high-temperature and 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, and 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 passing through the check valve 208 and the oil separator 206 sequentially passes through the check valve 208 and the second four-way valve 202B to flow out, and the flowing high-temperature and high-pressure gaseous refrigerant sequentially passes through the fifth solenoid valve 405B and the second indoor expansion valve of the second indoor unit 300B to enter the second indoor heat exchanger 301B, is condensed into a medium-temperature and high-pressure liquid refrigerant by the second indoor heat exchanger 301B, and flows out through the second indoor expansion valve of the second indoor unit 300B. Further, the refrigerant flowing out of the second indoor expansion valve is divided into two parts, that is, a part of the refrigerant flowing out of the second indoor expansion valve enters the first indoor heat exchanger 301A through the third expansion valve of the first indoor unit 300A, is evaporated into a low-temperature and low-pressure gaseous refrigerant by the first indoor heat exchanger 301A, and enters the gas-liquid separator 205 through the fourth solenoid valve 405A; the other part of the refrigerant flowing out of the second indoor expansion valve sequentially passes through the third solenoid valve 403, enters the outdoor heat exchanger 203, is evaporated into a low-temperature and low-pressure gaseous refrigerant by the outdoor heat exchanger 203, and the low-temperature and low-pressure gaseous refrigerant flowing out of the outdoor heat exchanger 203 passes through the first four-way valve 202A and enters the gas-liquid separator 205. The low-temperature and low-pressure gaseous refrigerant flowing out of the gas-liquid separator 205 enters a suction port of the compressor 201; the low-temperature low-pressure gaseous refrigerant is compressed into a high-temperature high-pressure gaseous refrigerant by the compressor 201, and is discharged from the compressor 201, so that the operation of the cooling/heating and heating main body of the air conditioning system is completed, namely the second asynchronous cooling and heating mode is completed.

5. First refrigerant recovery mode

When the multi-split air conditioning system 100 is in the first refrigerant recovery mode, the outdoor heat exchanger 203 operates as a condenser, the indoor heat exchangers of the indoor units each operate as an evaporator, the first solenoid valve 401 is in an open state, the second solenoid valve 402 is in a closed state, the third solenoid valve 403 is in a closed state, the first expansion valve 411 is in an open state, and the second expansion valve is in an open state. The third indoor expansion valve corresponding to the indoor unit in which refrigerant leakage has occurred is closed, and the third indoor expansion valve corresponding to the indoor unit in which refrigerant leakage has not occurred is opened.

The operation cycle of the first refrigerant recovery mode of the air conditioning system will be described in detail, taking an example in which the refrigerant in the first indoor unit 300A leaks and the refrigerant in the second indoor unit 300B does not leak. Referring to fig. 1, as shown in fig. 12, a D port of first four-way valve 202A is connected to a C port, and an E port is connected to an S port; the D port of second four way valve 202B is connected to the C port and the E port is connected to the S port. The first solenoid valve 401 is in an open state, the second solenoid valve 402 is in a closed state, the third solenoid valve 403 is in a closed state, the first expansion valve 411 is in a closed state, the first indoor expansion valve is in an open state, and the second indoor expansion valve is in an open state. The third indoor expansion valve 302A of the first indoor unit 300A is closed, the third indoor expansion valve 302B of the second indoor unit is opened, and normally, the opening degree at which the third indoor expansion valve 302B of the second indoor unit is opened is at the maximum opening degree value.

As shown in fig. 12, the flow direction of the refrigerant flowing through the second indoor unit 300B of the indoor unit 300 is: (8) → (9) → (11) → (12B) → (14A) → (15A) → (16A) → (17A) → (18A) → (19) → (1) → (2) → (3) → (4) → (5) → (6) → (20) and (8) → (9) → (11) → (13B) → (14B) → (15B) → (16B) → (17B) → (18B) → (19) → (1) → (2) → (3) → (4) → (5) → (20).

As shown in fig. 12, the refrigerant flow directions of the outdoor unit 200 are: (1) → (2) → (3) → (4) → (5) → (6) → (20).

Specifically, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 201 enters the oil separator 206, and the refrigerant entering the oil separator 206 is divided into two parts. Wherein, a part of the oil enters the inlet of the gas-liquid separator 205 through the oil return capillary 207; the other part of the high-temperature and high-pressure gaseous refrigerant passing through the oil separator 206 enters the outdoor heat exchanger 203 through the check valve 208 and the first four-way valve 202A. The high-temperature and high-pressure gaseous refrigerant is condensed into a medium-temperature and high-pressure liquid refrigerant in the outdoor heat exchanger 203. Further, the medium-temperature and high-pressure liquid refrigerant passes through the outdoor expansion valve 204 and the first solenoid valve 401 of the refrigerant recovery device 400 in sequence, and then is stored in the receiver 404. After the low-temperature and low-pressure liquid refrigerant in the pipeline (8) and the pipeline (9) flows into the third indoor expansion valve 302B of the second indoor unit to form the low-temperature and low-pressure liquid refrigerant, the low-temperature and low-pressure liquid refrigerant flows into the second indoor heat exchanger 301B again and is evaporated into the low-temperature and low-pressure gaseous refrigerant by the second indoor heat exchanger 301B. After the low-temperature and low-pressure gaseous refrigerant separately passes through the second indoor expansion valve of the second indoor unit 300B and the fifth electromagnetic valve 405B and enters the second four-way reversing valve, the low-temperature and low-pressure gaseous refrigerant enters the gas-liquid separator 205; and the low-temperature and low-pressure gaseous refrigerant after passing through the first indoor expansion valve 304B and the fourth solenoid valve 405A of the second indoor unit enters the gas-liquid separator 205. The low-temperature low-pressure gaseous refrigerant flowing out of the gas-liquid separator 205 enters a suction port of the compressor 201, and the low-temperature low-pressure gaseous refrigerant is compressed into a high-temperature high-pressure gaseous refrigerant by the compressor 201 and discharged from the compressor 201, so that the operation in the first refrigerant recovery mode of the air conditioning system is completed.

Optionally, when the first refrigerant recovery mode is in operation, the third indoor expansion valve corresponding to the indoor unit with refrigerant leakage is closed, and meanwhile, the third indoor expansion valve corresponding to the indoor unit without refrigerant leakage is at the maximum opening degree.

In an exemplary case where the refrigerant of the first indoor unit 300A leaks and the refrigerant of the second indoor unit 300B does not leak, the opening degree of the third indoor expansion valve 302B of the second indoor unit is opened to the maximum value while the third indoor expansion valve 302A of the first indoor unit 300A is closed.

6. Second refrigerant recovery mode

When the multi-split air conditioning system 100 is in the second refrigerant recovery mode, the outdoor heat exchanger 203 operates as an evaporator, the indoor heat exchanger operates as a condenser, the first solenoid valve 401 is in a closed state, the second solenoid valve 402 is in an open state, the third solenoid valve 403 is in a closed state, the first expansion valve 411 is in a closed state, the first indoor expansion valve is in a closed state, and the second indoor expansion valve is in an open state.

The operation cycle of the second refrigerant recovery mode of the air conditioning system will be described in detail, taking the leakage of the outdoor unit 200 as an example. With reference to fig. 1, as shown in fig. 13, an S port of first four-way valve 202A is connected to a C port, an E port is connected to a D port, an S port of second four-way valve 202B is connected to a C port, and an E port is connected to a D port; the first solenoid valve 401 is closed, the third solenoid valve 403 is closed, the second solenoid valve 402 is opened, the fifth solenoid valve 405B is opened, both the first indoor expansion valve 304A of the first indoor unit and the first indoor expansion valve 304B of the second indoor unit are closed, both the second indoor expansion valve 305A of the first indoor unit and the second indoor expansion valve of the second indoor unit 300B are opened, and all other solenoid valves, other indoor expansion valves, other outdoor expansion valves 204, other expansion valves, and other stop valves in the multi-split air conditioning system 100 shown in fig. 13 are opened.

As shown in fig. 13, the refrigerant flowing through the first indoor unit 300A of the indoor unit 300 has the following flow directions: (7) → 6 → 5 → 4 → 3 → 19 → 1 → 2 → 18A → 17A → 16A → 15A → 14A → 12A → 10 → 9 → 21.

As shown in fig. 13, the refrigerant circuit flowing through the second indoor unit 300B of the indoor unit 300 is: (7) → (6) → (5) → (4) → (3) → (19) → (1) → (2) → (18A) → (17A) → (16A) → (15A) → (14A) → (12B) → (11) → (9) → (21).

Refrigerant flow direction of the outdoor unit 200: (3) → (19) → (1).

It should be noted that when the refrigerant leakage of the outdoor unit 200 is detected, no matter whether the multi-split air-conditioning system 100 is in the synchronous cooling mode, the synchronous heating mode, the first asynchronous cooling and heating mode or the second asynchronous cooling and heating mode, the multi-split air-conditioning system 100 is switched to the synchronous heating mode while the first electromagnetic valve 401 is controlled to be in the closed state, the second electromagnetic valve 402 is controlled to be in the open state, and the third electromagnetic valve 403 is controlled to be in the closed state.

Specifically, the high-temperature and 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 portions. Wherein, a part of the oil enters the inlet of the gas-liquid separator 205 through the oil return capillary 207; the other part of the high-temperature and high-pressure gaseous refrigerant passing through the oil separator 206 passes through the check valve 208, the second four-way valve 202B and the fifth solenoid valve 405B in sequence, and then is divided to flow through the second indoor expansion valve 305A of the first indoor unit to enter the first indoor heat exchanger 301A of the first indoor unit 300A and flow through the second indoor expansion valve of the second indoor unit 300B to enter 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 high-temperature and high-pressure gas refrigerant, and condense the refrigerant into a medium-temperature and high-pressure liquid refrigerant. The condensed medium-temperature and high-pressure liquid refrigerants respectively pass through the third indoor expansion valve 302A of the first indoor unit 300A and the third indoor expansion valve 302B of the second indoor unit, and then are merged. The merged refrigerant is stored in the accumulator 404 through the second solenoid valve 402. The refrigerant in the outdoor unit 200 is evaporated into a low-temperature and low-pressure gaseous refrigerant by 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 a suction port of the compressor 201; the low-temperature and low-pressure gaseous refrigerant is compressed into a high-temperature and high-pressure gaseous refrigerant by the compressor 201, and is discharged from the compressor 201, so that the operation of the second refrigerant recovery mode of the air conditioning system is completed.

7. Refrigerant release pattern

When the multi-split air conditioning system 100 is in the refrigerant release mode, the outdoor heat exchanger 203 operates as a condenser, each indoor heat exchanger operates as an evaporator, 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, the first expansion valve 411 is in an open state, and the first indoor expansion valve of each indoor unit and the second indoor expansion valve of each indoor unit are in an open state.

For example, an operation cycle of the refrigerant release mode of the air conditioning system will be described in detail, taking as an example that both the first indoor unit 300A and the second indoor unit 300B are indoor units requiring cooling.

Referring to FIG. 1, as shown in FIG. 14, a D port of first four-way valve 202A is connected to a C port, an E port is connected to an S port, a D port of second four-way valve 202B is connected to a C port, and an E port is connected to an S port; the first solenoid valve 401 is closed, the second solenoid valve 402 is closed, the third solenoid valve 403 is open, the fourth solenoid valve 405A is open, the fifth solenoid valve 405B is open, both the first indoor expansion valve 304A of the first indoor unit and the first indoor expansion valve 304B of the second indoor unit are open, the first expansion valve 411 is closed, both the second indoor expansion valve 305A of the first indoor unit and the second indoor expansion valve of the second indoor unit 300B are open, and all other solenoid valves, other indoor expansion valves, other outdoor expansion valves 204, other expansion valves, and other shutoff valves are open in the multi-split air conditioning system 100 shown in fig. 14.

As shown in fig. 14, the refrigerant circulation circuit flowing through the first indoor unit 300A of the indoor unit 300 includes: (1) → (2) → (3) → (4) → (5) → (6) → (7) → (8) → (9) → (10) → (12A) → (14A) → (15A) → (16A) → (17A) → (18A) → (19) → (1), and (1) → (2) → (3) → (4) → (5) → (6) → (7) → (8) → (9) → (10) → (13A) → (14B) → (15B) → (16B) → (17B) → (18B) → (19) → (1).

As shown in fig. 14, the refrigerant circulation circuit flowing through the second indoor unit 300B of the indoor unit 300 is: (1) → (2) → (3) → (4) → (5) → (6) → (7) → (8) → (9) → (11) → (12B) → (14A) → (15A) → (16A) → (17A) → (18A) → (19) → (1) and (1) → (2) → (3) → (4) → (5) → (6) → (7) → (8) → (9) → (11) → (13B) → (14B) → (15B) → (16B) → (17B) → (18B) → (19) → (1).

The refrigerant release flow path for releasing the refrigerant shown in fig. 14 is: (22) → 23 → 16A → 17A → 18A → 19 → 1 and 22 → 24 → 16B → 17B → 18B → 19 → 1.

Specifically, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 201 enters the oil separator 206, and the refrigerant entering the oil separator 206 is divided into two parts. Wherein, a part of the oil enters the inlet of the gas-liquid separator 205 through the oil return capillary 207; the other part of the high-temperature and high-pressure gaseous refrigerant passing through the oil separator 206 enters the outdoor heat exchanger 203 through the check valve 208 and the first four-way valve 202A. The high-temperature and high-pressure gaseous refrigerant is condensed into a medium-temperature and high-pressure liquid refrigerant in the outdoor heat exchanger 203. Further, the medium-temperature and high-pressure liquid refrigerant sequentially passes through the third solenoid valve 403 of the refrigerant recovery device 400, and is then split into two parts, one part of the medium-temperature and high-pressure liquid refrigerant flows into the third indoor expansion valve 302A of the first indoor unit 300A to form a low-temperature and low-pressure liquid refrigerant, and then flows into the first indoor heat exchanger 301A, and is evaporated into a low-temperature and low-pressure gaseous refrigerant by the first indoor heat exchanger 301A; after another part of the refrigerant flows into the second indoor expansion valve of the second indoor unit 300B to form a low-temperature low-pressure liquid refrigerant, the low-temperature low-pressure liquid refrigerant flows into the second indoor heat exchanger 301B again, and is evaporated into a low-temperature low-pressure gaseous refrigerant by the second indoor heat exchanger 301B. The low-temperature and low-pressure gaseous refrigerant evaporated by the first indoor heat exchanger 301A and the second indoor heat exchanger 301B is split and then merged, specifically, split is performed first: the low-temperature and low-pressure gaseous refrigerant evaporated by the first indoor heat exchanger 301A is distributed to the first indoor expansion valve 304A of the first indoor unit and the second indoor expansion valve 305A of the first indoor unit; and the low-temperature and low-pressure gaseous refrigerant evaporated by the second indoor heat exchanger 301B is distributed to the first indoor expansion valve 304B of the second indoor unit and the second indoor expansion valve of the second indoor unit 300B. And (3) converging: the low-temperature and low-pressure refrigerant flowing out through the first indoor expansion valve 304A of the first indoor unit and the low-temperature and low-pressure refrigerant flowing out through the first indoor expansion valve 304B of the second indoor unit are merged first and then merged with the refrigerant released through the first expansion valve 411 in the liquid storage tank 404 to be a first refrigerant, and the low-temperature and low-pressure refrigerant flowing out through the second indoor expansion valve 305A of the first indoor unit and the low-temperature and low-pressure refrigerant flowing out through the second indoor expansion valve of the second indoor unit 300B are merged first and then merged with the refrigerant released through the first expansion valve 411 in the liquid storage tank 404 to be a second refrigerant. Further, the merged first refrigerant passes through the fourth solenoid valve 405A, and then, the merged second refrigerant passes through the fifth solenoid valve 405B and the second four-way selector valve in sequence, and then, the merged first refrigerant and the merged second refrigerant are merged again to form a low-temperature low-pressure gaseous refrigerant, and the low-temperature low-pressure gaseous refrigerant formed by the merging again enters the gas-liquid separator 205. The low-temperature low-pressure gaseous refrigerant flowing out of the gas-liquid separator 205 enters the return air port of the compressor 201, and the low-temperature low-pressure gaseous refrigerant is compressed into a high-temperature high-pressure gaseous refrigerant by the compressor 201 and discharged from the air outlet of the compressor 201, so that the refrigerant release operation of the air conditioning system is completed.

Based on the seven different operation modes, the multi-split air conditioning system 100 may provide operation modes corresponding to different scenes. Specifically, when all the indoor environment temperatures are required to be too high and refrigeration is required, the operation mode of the multi-split air conditioning system 100 is switched to the synchronous refrigeration mode to reduce the indoor environment temperatures. When all the indoor environment temperatures are required to be too low and heating is required, the operation mode of the multi-split air conditioning system 100 is switched to the synchronous heating mode to increase the indoor environment temperatures. When different indoor environment temperatures are needed to be high and low, part of the indoor environment temperatures need to be heated, and part of the indoor environment temperatures need to be cooled, the operation mode of the multi-split air conditioning system 100 is switched to the first asynchronous cooling and heating mode or the second asynchronous cooling and heating mode, so that the indoor environment temperatures of the indoor units can be flexibly adjusted. When the refrigerant leaked from the indoor unit needs to be recovered, the multi-split air conditioning system 100 may be switched to the first refrigerant recovery mode, and the refrigerant leaked from the indoor unit may be recovered by the refrigerant recovery device 400. When it is necessary to recover the refrigerant leaked from the outdoor unit 200, the multi-split air conditioning system 100 may be switched to the second refrigerant recovery mode, and the refrigerant leaked from the outdoor unit 200 may be recovered by the refrigerant recovery device 400. When the refrigerant recovered in the refrigerant recovery device 400 needs to be utilized, the multi-split air conditioning system 100 may be adjusted to the refrigerant release mode, and the recovered refrigerant is released to the first pipeline and the second pipeline, so that the multi-split air conditioning system 100 uses the recovered refrigerant in the cooling operation or the heating operation process.

In some embodiments, the multi-split air conditioning system 100 further includes a controller (not shown in fig. 1).

In some embodiments, the controller is a device capable of generating an operation control signal according to the command operation code and the timing signal, and instructing the multi-split air conditioning system to execute the control command. For example, the controller may be a Central Processing Unit (CPU), a general purpose processor Network (NP), a Digital Signal Processor (DSP), a microprocessor, a microcontroller, a Programmable Logic Device (PLD), or any combination thereof. The controller may also be other devices with processing functions, such as a circuit, a device, or a software module, which is not limited in any way by the embodiments of the present application.

Although not shown in fig. 1, the multi-split air conditioning system may further include a power supply device (e.g., a battery and a power management chip) for supplying power to each component, and the battery may be logically connected to the controller through the power management chip, so as to implement functions such as power consumption management of the multi-split air conditioning system through the power supply device.

In some embodiments, the controller is electrically connected with the indoor refrigerant leakage detection device in each indoor unit; the controller is configured to: the method comprises the steps of obtaining a detection result of each indoor refrigerant leakage detection device, wherein the detection result of one indoor refrigerant leakage detection device is used for indicating whether the indoor unit where the refrigerant leakage detection device is located leaks refrigerant or not; determining whether an indoor unit 300 having refrigerant leakage exists according to a detection result of each indoor refrigerant leakage detection device; and if so, controlling the multi-split air conditioning system to operate in a first refrigerant recovery mode.

In this way, the multi-split air conditioning system can determine the indoor unit having refrigerant leakage in the indoor unit 300 according to the detection result of the indoor refrigerant leakage detection device. When the indoor unit 300 has a refrigerant leak, the multi-split air conditioning system is controlled to switch to the first refrigerant recovery mode, and the refrigerant leaking from the indoor unit is recovered to the refrigerant recovery device 400. On one hand, the risk of the indoor environment caused by the refrigerant of the indoor unit leaking into the indoor environment is avoided, and the safety of the multi-split air-conditioning system is improved; on the other hand, the refrigerant is recovered by the refrigerant recovery device 400, so that the amount of the refrigerant discharged from the outdoor unit 200 to the outdoor environment is greatly reduced, and the environmental friendliness of the multi-split air conditioning system is improved.

In some embodiments, the controller is further configured to: and when the multi-split air conditioning system operates in the first refrigerant recovery mode, closing an indoor expansion valve in the indoor unit with refrigerant leakage.

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 where refrigerant leakage occurs is closed to prevent the refrigerant from continuously entering the indoor unit where refrigerant leakage occurs, so that the refrigerant in the indoor unit where refrigerant leakage occurs is prevented from leaking into an indoor environment, and thus, safe use of the multi-split air conditioning system by a user is ensured.

Optionally, when the multi-split air conditioning system operates in the first refrigerant recovery mode, the opening degree of the indoor expansion valve of the indoor unit without refrigerant leakage in the indoor unit 300 is adjusted to the maximum opening degree value, so that the refrigerant in the pipeline communicated with the indoor expansion valve of the indoor unit with refrigerant leakage is more quickly recovered to the refrigerant recovery device 400 through the indoor unit and the outdoor unit 200, thereby increasing the recovery speed of the refrigerant leaked from the indoor unit and ensuring the refrigerant recovery efficiency of the multi-split air conditioning system.

In some embodiments, the controller is further configured to: in the first refrigerant recovery mode, when a refrigerant recovery stop condition is satisfied, the fourth electromagnetic valve 405 is controlled to be closed; the refrigerant recovery stopping condition comprises one or more of the following conditions: the time length of the multi-split air conditioning system operating in the first refrigerant recovery mode reaches a preset time length; alternatively, the pressure of the refrigerant entering the compressor 201 is within a preset pressure range.

It should be noted that the preset pressure range is determined according to the atmospheric pressure of the outdoor environment.

Alternatively, the pressure of the refrigerant in the compressor 201 may be detected by a first outdoor pressure sensor 209 disposed at an inlet of the compressor 201 as shown in fig. 2.

Based on this, by setting the refrigerant recovery stopping condition, the time for finishing the refrigerant recovery can be determined, so that the refrigerant is recovered when the refrigerant quantity in the pipeline of the multi-split air-conditioning system is in a reasonable range, the first refrigerant recovery mode is still executed under the condition that no refrigerant exists in the pipeline of the multi-split air-conditioning system, the abnormality or damage of the multi-split air-conditioning system is avoided, and the safety and the service life of the multi-split air-conditioning system are further improved.

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 exchangers in the indoor units through pipelines; when the multi-split air conditioning system is in a cooling mode, a heating mode, and a first refrigerant recovery mode, the fifth electromagnetic valve 406 is in an open state.

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, the fifth electromagnetic valve 406 is controlled to be closed; the refrigerant recovery stopping condition comprises one or more of the following conditions: the time length of the multi-split air conditioning system operating in the first refrigerant recovery mode reaches a preset time length; alternatively, the pressure of the refrigerant entering the compressor 201 is within a preset pressure range.

In some embodiments, the outdoor unit 200 controller is electrically connected to the outdoor refrigerant leakage detecting device of the outdoor unit 200; the controller is configured to: acquiring a detection result of an outdoor refrigerant leakage detection device, wherein the detection result of the outdoor refrigerant leakage detection device is used for indicating whether the outdoor unit 200 generates refrigerant leakage; and if the detection result of the outdoor refrigerant leakage detection device indicates that the outdoor unit 200 has refrigerant leakage, controlling the multi-split air-conditioning system to operate in a second refrigerant recovery mode.

In this way, the multi-split air conditioning system can determine whether the outdoor unit 200 has refrigerant leakage according to the detection result of the outdoor refrigerant leakage detecting device. Under the condition that the outdoor unit 200 leaks the refrigerant, the multi-split air conditioning system is controlled to be switched to the second refrigerant recovery mode to operate, and the refrigerant leaked from the outdoor unit 200 is recovered to the refrigerant recovery device 400, so that the refrigerant is recovered by the refrigerant recovery device 400, the amount of the refrigerant discharged from the outdoor unit 200 to the outdoor environment is greatly reduced, and the environmental friendliness of the multi-split air conditioning system is improved.

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

In this embodiment, when the multi-split air-conditioning system operates in the second refrigerant recovery mode, the outdoor expansion valve 204 is controlled to be at the maximum opening value, so that the refrigerant in the pipeline communicated with the outdoor expansion valve 204 is more quickly recovered to the refrigerant recovery device 400 through the outdoor unit 200 and the indoor unit, thereby increasing 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.

In some embodiments, the controller is further configured to: in the second refrigerant recovery mode, when the refrigerant recovery stop condition is satisfied, the fourth electromagnetic valve 405 is controlled to be closed; the refrigerant recovery stopping condition comprises one or more of the following conditions: the time length of the multi-split air conditioning system operating in the second refrigerant recovery mode reaches the preset time length; alternatively, the pressure of the refrigerant entering the compressor 201 is within a preset pressure range.

Based on this, by setting the refrigerant recovery stop condition, the time for finishing the refrigerant recovery can be determined, so that the refrigerant is recovered when the refrigerant quantity in the pipeline of the multi-split air-conditioning system is in a reasonable range, the problem that the multi-split air-conditioning system is abnormal or damaged due to the fact that the second refrigerant recovery mode is still executed under the condition that no refrigerant exists in the pipeline of the multi-split air-conditioning system is avoided, and the safety and the service life of the multi-split air-conditioning system are improved.

Based on the above embodiment, the controller is further configured to: in the second refrigerant recovery mode, when the refrigerant recovery stop condition is met, the fifth electromagnetic valve 406 is controlled to be closed; the refrigerant recovery stopping condition comprises one or more of the following conditions: the time length of the multi-split air conditioning system operating the second refrigerant recovery mode reaches a preset time length; alternatively, the pressure of the refrigerant entering the compressor 201 is within a preset pressure range.

In this embodiment, the indoor expansion valve corresponding to the indoor unit in which refrigerant leakage occurs in the indoor unit 300 is in a closed state. After the refrigerant is recovered, the fourth electromagnetic valve 405 and the fifth electromagnetic valve 406 are controlled to be closed, so that the indoor units with refrigerant leakage in the indoor unit 300 are freely separated from the refrigerant recovery device 400 and the outdoor unit 200, the indoor units with refrigerant leakage are not affected by the refrigerant recovery device 400 and the outdoor unit 200 in the process of replacing the indoor units with refrigerant leakage, and the convenience of installing or replacing the indoor units is improved.

A refrigerant recovery process will be described in an exemplary manner with reference to a control flowchart of the multi-split air conditioning system shown in fig. 15.

And S141, detecting the leakage condition of the refrigerant in the indoor unit and the outdoor unit.

And S142, controlling the multi-split air conditioning system to operate in a first refrigerant recovery mode under the condition that the indoor unit with refrigerant leakage is detected in the indoor unit.

And S143, controlling the multi-split air conditioning system to operate in a second refrigerant recovery mode under the condition that refrigerant leakage of the outdoor unit is detected.

And S144, keeping the original operation mode to operate under the condition that the refrigerant in the indoor unit and the outdoor unit is detected to be not leaked.

The original operation mode may be a mode in which the air conditioning system is operated, such as a cooling mode, a heating mode, and a dehumidification mode.

When the multi-split air conditioning system is in a 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; 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, and the third electromagnetic valve is in a closed state.

Further, the control process of the multi-split air conditioning system in the first refrigerant recovery mode is as follows.

(1) And detecting that an indoor unit with refrigerant leakage exists in the indoor unit. The indoor unit with refrigerant leakage usually sends out early warning information. The early warning information is used for indicating that the indoor unit has refrigerant leakage. The early warning information can be early warning in the form of voice, characters or light.

(2) And judging whether the multi-split air conditioning system is in a refrigeration mode or not.

(3) If not, after the multi-split air conditioning system is switched to the refrigerating mode, the indoor expansion valve corresponding to the indoor unit with refrigerant leakage is controlled to be in a closed state, 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.

(4) If yes, controlling the first electromagnetic valve to be in an open state, and controlling an indoor expansion valve corresponding to the indoor unit with refrigerant leakage to be in a closed state, the first electromagnetic valve to be in an open state, the second electromagnetic valve to be in a closed state and the third electromagnetic valve to be in a closed state.

(5) When the time length of the multi-split air-conditioning system running in the first refrigerant recovery mode reaches the preset time length; or when the pressure of the refrigerant entering the compressor is within a preset pressure range, controlling the fourth electromagnetic valve to be closed, and sending first replacement information. The first replacement information is used for prompting a user to replace the indoor unit with refrigerant leakage.

(6) And controlling the multi-split air conditioner system to stop running.

Further, the control process that the multi-split air conditioning system is in the second refrigerant recovery mode is described as follows.

(1) The refrigerant leakage of the outdoor unit is detected. The outdoor unit will typically send out warning information. The early warning information is used for indicating that the outdoor unit has refrigerant leakage. The early warning information can be early warning in the form of voice, characters or light.

(2) And judging whether the multi-split air conditioning system is in a heating mode or not.

(3) If not, the multi-split air-conditioning system is switched to a heating mode, then the first electromagnetic valve is controlled to be in a closed state, the second electromagnetic valve is in an open state, and the third electromagnetic valve is in a closed state.

(4) If yes, the first electromagnetic valve is controlled to be in a closed state, the second electromagnetic valve is controlled to be in an open state, and the third electromagnetic valve is controlled to be in a closed state.

(5) When the time length of the multi-split air conditioning system in the second refrigerant recovery mode reaches the preset time length; or when the pressure of the refrigerant entering the compressor is within the preset pressure range, the fourth electromagnetic valve is controlled to be closed, and second replacement information is sent. The second replacement information is used for prompting the user to replace the outdoor unit.

(6) And controlling the multi-split air conditioner system to stop running.

A refrigerant releasing process will be described with reference to a control flowchart of the multi-split air conditioning system shown in fig. 16.

And S151, under the condition that the first refrigerant recovery mode or the second refrigerant recovery mode is completed, if an operation signal for indicating that the multi-split air-conditioning system operates in the synchronous refrigeration mode is received, directly controlling the multi-split air-conditioning system to operate in the refrigerant release mode.

When the multi-split 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 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.

S152, when the first refrigerant recovery mode or the second refrigerant recovery mode is completed, if an operation signal for instructing the multi-split air conditioning system to operate in another mode of the synchronous refrigeration mode is received, the multi-split air conditioning system is switched to the synchronous refrigeration mode and then operates the refrigerant release mode.

In addition, the embodiment of the present application provides a hardware structure and/or a software module corresponding to each function. Those of skill in the art will readily appreciate that the various illustrative modules and algorithm steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

In the embodiment of the present application, the controller may be divided into the functional modules according to the above method example, for example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. Optionally, the division of the modules in the embodiment of the present application is schematic, and is only a logic function division, and there may be another division manner in actual implementation.

As shown in fig. 17, the controller 2000 includes a processor 2001, and optionally, a memory 2002 and a communication interface 2003, which are connected to the processor 2001. The processor 2001, memory 2002, and communication interface 2003 are connected by a bus 2004.

The processor 2001 may be a Central Processing Unit (CPU), a general purpose processor Network (NP), a Digital Signal Processor (DSP), a microprocessor, a microcontroller, a Programmable Logic Device (PLD), or any combination thereof. The processor 2001 may also be any other means having a processing function such as a circuit, device or software module. The processor 2001 may also include a plurality of CPUs, and the processor 2001 may be one single-core (single-CPU) processor or a multi-core (multi-CPU) processor. A processor herein may refer to one or more devices, circuits, or processing cores that process data (e.g., computer program instructions).

The memory 2002 may 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 disk read-only memory (CD-ROM) or other optical disk storage, optical disk storage (including compact disk, laser disk, optical disk, digital versatile disk, blu-ray disk, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer, which are not limited by the embodiments of the present application. The memory 2002 may be separate or integrated with the processor 2001. The memory 2002 may include, among other things, 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 embodiment of the present application.

Communication interface 2003 may be used to communicate with other devices or communication networks (e.g., an Ethernet, radio Access Network (RAN), wireless Local Area Network (WLAN), etc.. Communication interface 2003 may be a module, circuitry, transceiver, or any other device capable of communicating.

The bus 2004 may be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. The bus 2004 may be divided into an address bus, a data bus, a control bus, and the like. For ease of illustration, only one thick line is shown in FIG. 17, but this does not mean only one bus or one type of bus.

Embodiments of the present invention also provide a computer-readable storage medium, where the computer-readable storage medium includes computer-executable instructions, and when the computer-executable instructions are executed on a computer, the computer is caused to execute the method provided in the foregoing embodiments.

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

Those skilled in the art will recognize that, in one or more of the examples described above, the functions described in this invention may be implemented in hardware, software, firmware, or any combination thereof. When implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer.

Through the above description of the embodiments, it is clear to those skilled in the art that, for convenience and simplicity of description, the foregoing division of the functional modules is merely used as an example, and in practical applications, the above function distribution may be completed by different functional modules according to needs, that is, the internal structure of the device may be divided into different functional modules to complete all or part of the above described functions.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described embodiments of the apparatus are merely illustrative, and for example, a module or a unit may be divided into only one logic function, and another division may be implemented in practice. For example, multiple modules or components may be combined or may be integrated into another device, or some features may be omitted, or not implemented. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or modules, and may be in an electrical, mechanical or other form. Modules described as separate components may or may not be physically separate, and components shown as modules may be one physical module or multiple physical modules, may be located in one place, or may be distributed in multiple different places. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit may be implemented in the form of hardware, or may also be implemented in the form of a software functional unit. The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application may be essentially or partially contributed to by the prior art, or all or part of the technical solutions may be embodied in the form of a software product, where the software product is stored in a storage medium and includes several instructions to enable a device (which may be a single chip, a chip, or the like) or a processor (processor) to execute all or part of the steps of the methods according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a U disk, a removable hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

The above is only an embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions within the technical scope of the present disclosure should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A multi-split air conditioning system, comprising:

the indoor unit comprises a plurality of indoor units, each indoor unit comprises an indoor heat exchanger, a first indoor expansion valve and a second indoor expansion valve, and the first end of each indoor heat exchanger is connected with the second end of the first indoor expansion valve and the second end of the second indoor expansion valve respectively;

the outdoor unit comprises a compressor, an outdoor heat exchanger, a first four-way valve and a second four-way valve; the first end of the second four-way valve is connected with the first end of each first indoor expansion valve through a first pipeline, the second end of the second four-way valve is connected with the air outlet of the compressor, and the third end of the second four-way valve is connected with the first end of each second indoor expansion valve through a second pipeline; the first end of the first four-way valve is connected with the first pipeline, the second end of the first four-way valve is connected with the air outlet of the compressor, and the fourth end of the first four-way valve is connected with the first end of the outdoor heat exchanger; the return air port of the compressor is connected with the first pipeline;

the refrigerant recovery device comprises a first electromagnetic valve, a third electromagnetic valve, a first expansion valve and a liquid storage tank; the second end of the outdoor heat exchanger is connected with the first opening of the liquid storage tank through a first electromagnetic valve and is connected with the second end of each indoor heat exchanger through a third electromagnetic valve; and a third opening of the liquid storage tank is respectively communicated with the first pipeline and the second pipeline through a first expansion valve.

2. A multi-split air conditioning system as recited in claim 1, wherein the refrigerant recovery device further includes a second solenoid valve; and a second opening of the liquid storage tank is connected with a second end of the indoor heat exchanger in each indoor unit through the second electromagnetic valve.

3. A multi-split air conditioning system as claimed in claim 2, wherein the multi-split air conditioning system has a plurality of operation modes, and the plurality of operation modes at least 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 a 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, the first expansion valve is in a closed state, the first indoor expansion valve is in an open state, and the second indoor expansion valve is in an open state;

when the multi-split air conditioning system is in a 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, the first expansion valve is in a closed state, the first indoor expansion valve is in a closed state, and the second indoor expansion valve is in an open state;

4. A multi-split air conditioning system as set forth in claim 3,

the refrigerant recovery device also comprises a first supercooling heat exchanger, wherein the first supercooling heat exchanger comprises a first channel and a second channel; a third opening of the liquid storage tank is respectively communicated with the first pipeline and the second pipeline through the first expansion valve and a first channel of the first supercooling heat exchanger in sequence; and the first end of the third electromagnetic valve is connected with the second end of the outdoor heat exchanger through the second channel of the first supercooling heat exchanger.

5. A multi-split air conditioning system as claimed in claim 4,

the refrigerant recovery device also comprises a first temperature sensor, wherein the first temperature sensor 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 also comprises a gas-liquid separator and a first outdoor pressure sensor, wherein the first outdoor pressure sensor is used for detecting the pressure value of a refrigerant at an inlet of the gas-liquid separator;

the multi-split air conditioning system further includes: a controller configured to:

when the multi-split air-conditioning system operates in a refrigerant release mode, acquiring a first temperature value detected by the first temperature sensor and a pressure value detected by the first outdoor pressure sensor;

if the difference value between the first temperature value and the second temperature value is greater than or equal to a first preset temperature value, controlling the first expansion valve to increase the opening degree, wherein the second temperature value is a saturation temperature value corresponding to the pressure value detected by the first outdoor pressure sensor; or,

and if the difference value between the first temperature value and the second temperature value is greater than a first preset temperature value, controlling the first expansion valve to reduce the opening degree.

6. A multi-split air conditioning system as set forth in claim 5,

the refrigerant recovery device also comprises a throttling device and a second supercooling heat exchanger; the second subcooling heat exchanger comprises a third pass and a fourth pass; a third opening of the liquid storage tank is also respectively communicated with the first pipeline and the second pipeline sequentially through a third channel of the throttling device and the second supercooling heat exchanger; and the second end of the third electromagnetic valve is connected with the indoor expansion valve through a fourth channel of the second supercooling heat exchanger.

7. A multi-split air conditioning system as claimed in claim 6,

the refrigerant recovery device also comprises a second temperature sensor, wherein the second temperature sensor is used for detecting the temperature value of the refrigerant flowing out of a third channel of the second supercooling heat exchanger;

the controller further configured to:

when the multi-split air conditioning system operates in a refrigerant release mode, acquiring a third temperature value detected by the second temperature sensor and a pressure value detected by the first outdoor pressure sensor;

if the difference value between the third temperature value and the second temperature value is greater than or equal to a second preset temperature value, ending the operation of the refrigerant release mode, wherein the second temperature value is a saturation temperature value corresponding to the pressure value detected by the first outdoor pressure sensor; or,

and if the difference value between the third temperature value and the second temperature value is smaller than a second preset temperature value, continuing to operate the refrigerant release mode.

8. A multi-split air conditioning system as set forth in claim 1,

the refrigerant recovery device further comprises a fourth electromagnetic valve and a fifth electromagnetic valve, wherein the fourth electromagnetic valve is arranged on the first pipeline, the first end of the fourth electromagnetic valve is connected with the first end of the second four-way valve, the second end of the fourth electromagnetic valve is connected with the first end of the first indoor expansion valve, the fifth electromagnetic valve is arranged on the second pipeline, the first end of the fifth electromagnetic valve is connected with the third end of the second four-way valve, and the second end of the fifth electromagnetic valve is connected with the first end of the second indoor expansion valve.

9. A multi-split air conditioning system as set forth in claim 8,

the refrigerant recovery device further comprises a sixth electromagnetic valve and a seventh electromagnetic valve, the sixth electromagnetic valve is arranged on the first pipeline, a first end of the sixth electromagnetic valve is connected with a second end of the fourth electromagnetic valve, and a second end of the sixth electromagnetic valve is connected with a first end of the first indoor expansion valve; the seventh solenoid valve is disposed on the second pipeline, a first end of the seventh solenoid valve is connected to a second end of the fifth solenoid valve, and a second end of the seventh solenoid valve is connected to a first end of the second indoor expansion valve.

10. A multi-split air conditioning system as recited in claim 9,

the refrigerant recovery device also comprises a second expansion valve;

a first end of the second expansion valve is connected with a fourth opening of the liquid storage tank, a second end of the second expansion valve is respectively communicated with a third pipeline and a fourth pipeline, the third pipeline is a pipeline between the fourth electromagnetic valve and the sixth electromagnetic valve, and the fourth pipeline is a pipeline between the fifth electromagnetic valve and the seventh electromagnetic valve; or,

the first end of the second expansion valve is communicated with a fifth pipeline, the second end of the second expansion valve is respectively communicated with a third pipeline and a fourth pipeline, and the fifth pipeline is a pipeline between the first electromagnetic valve and the first opening of the liquid storage tank.