Air conditioning system

Abstract

Provided is an air conditioning system (100), comprising an indoor unit (20), an outdoor unit (10) and a controller (50), which are connected to each other. The outdoor unit (10) comprises a first gas-liquid separator (120) and a second gas-liquid separator (121). The first gas-liquid separator (120) comprises a first container (140), multiple liquid branches, and an auxiliary throttling component. The multiple liquid branches are led out from a bottom portion of the first container (140), and are each connected to a compressor. The auxiliary throttling component is arranged on any one of the multiple liquid branches. The second gas-liquid separator (121) comprises a second container (142) and multiple outlet lines, the multiple outlet lines being led out from a lower portion of the second container (142) and each being connected to a compressor. The controller (50) is configured to, on the basis of an auxiliary throttling component operation parameter corresponding to a frequency band condition, drive the auxiliary throttling component to execute a corresponding action when a compressor exhaust superheat exceeds a reference exhaust superheat, and a compressor operation frequency meets a frequency band condition corresponding to various transition operation states.

Description

Air conditioning system

[0001] This application claims priority to Chinese Patent Application No. 202410549140.8, filed on May 06, 2024, Chinese Patent Application No. 202420822513.X, filed on April 19, 2024, and Chinese Patent Application No. 202420822794.9, filed on April 19, 2024, the contents of all of which are incorporated by reference in their entirety. TECHNICAL FIELD

[0002] The present disclosure relates to the field of air conditioning technology, and in particular, to an air conditioning system. BACKGROUND

[0003] A multi-split air conditioning system is a large refrigerant circulation system that can be connected to different types and different numbers of indoor units. The multi-split air conditioning system can independently adjust the cooling and heating of multiple rooms or areas, and the temperature of different rooms or areas can be independently controlled or combined control. The multi-split air conditioning system is suitable for buildings that require independent temperature control, including multiple rooms or areas, such as office buildings, schools, hotels, and large residences, etc.

[0004] SUMMARY

[0005] In one aspect, an air conditioning system is provided, comprising an indoor unit and at least one outdoor unit, the indoor unit being in communication with the at least one outdoor unit to form a refrigerant circuit. Any one of the at least one outdoor unit comprises a plurality of compressors, a switching valve, a first gas-liquid separator, a second gas-liquid separator, and a gas communication pipe. The plurality of compressors are configured to compress refrigerant so that low-pressure refrigerant is compressed to form high-pressure refrigerant. The switching valve is configured to switch the flow direction of the refrigerant in the refrigerant circuit. The first gas-liquid separator comprises a first container, a plurality of liquid branches, and an auxiliary throttling component. The plurality of liquid branches are arranged corresponding to the plurality of compressors, any one of the plurality of liquid branches being led out from the bottom of the first container and being in communication with one of the plurality of compressors. The auxiliary throttling component is arranged corresponding to the plurality of liquid branches, the auxiliary throttling component being arranged on any one of the plurality of liquid branches. The second gas-liquid separator comprises a second container and a plurality of outlet pipelines. Any one of the plurality of outlet pipelines is led out from the bottom of the second container and is connected to one of the plurality of compressors, respectively. The top of the first gas-liquid separator and the top of the second gas-liquid separator are in communication through the gas communication pipe. The outdoor unit further comprises a controller, the controller being configured to: in a case where any one of the plurality of compressors satisfies: the discharge superheat of the compressor is greater than a reference discharge superheat, and the operating frequency of the compressor is located in any one of a plurality of frequency band conditions corresponding to a plurality of transition operating states of the air conditioning system, drive the auxiliary throttling component to perform a corresponding action according to a first preset operating parameter of the auxiliary throttling component corresponding to the frequency band condition; wherein the reference discharge superheat serves as a reference value for identifying whether the discharge superheat of the compressor is too high.

[0006] In another aspect, an air conditioning system is provided, including a plurality of indoor units, an outdoor unit, and a liquid pipe. The indoor unit is connected to the plurality of indoor units. The liquid pipe connects the outdoor unit and the plurality of indoor units. The outdoor unit includes a compressor, an outdoor heat exchanger, a subcooler, an auxiliary pipeline, and an auxiliary valve. The compressor is configured to compress a refrigerant to form high-pressure refrigerant from low-pressure refrigerant. The outdoor heat exchanger is configured to exchange heat between outdoor air and the refrigerant passing through the outdoor heat exchanger. The subcooler is disposed between the outdoor heat exchanger and the plurality of indoor units, and is configured to separate a portion of high-temperature high-pressure liquid refrigerant in the liquid pipe. The subcooler includes an auxiliary pipeline, an auxiliary valve, a first gas-liquid separator, and a second gas-liquid separator. The first end of the auxiliary pipeline is connected to the outdoor heat exchanger. The auxiliary valve is disposed in the auxiliary pipeline. The second end of the auxiliary pipeline is connected to the first gas-liquid separator and connected to the suction side of the compressor through the first gas-liquid separator. The second gas-liquid separator is connected to the suction side of the compressor. When the auxiliary valve is in a fully open state, the refrigerant is guided into the first gas-liquid separator through the auxiliary pipeline. BRIEF DESCRIPTION OF DRAWINGS

[0007] FIG. 1 is a structural diagram of two gas-liquid separators arranged in parallel in the related art;

[0008] FIG. 2 is a structural diagram of an air conditioning system according to some embodiments;

[0009] FIG. 3 is a structural diagram of an outdoor unit of an air conditioning system according to some embodiments;

[0010] FIG. 4 is a refrigerant flow diagram of an outdoor unit of an air conditioning system in a cooling mode according to some embodiments;

[0011] FIG. 5 is a refrigerant flow diagram of an outdoor unit of an air conditioning system in a heating mode according to some embodiments;

[0012] FIG. 6 is another structural diagram of an air conditioning system according to some embodiments;

[0013] FIG. 7 is a pressure loss ratio diagram of a gas-liquid separator according to some embodiments;

[0014] FIG. 8 is a comparison diagram of total pressure loss of a gas-liquid separator of an air conditioning system in the present disclosure and the related art according to some embodiments;

[0015] FIG. 9 is a diagram of the relationship between oil discharge rate and operating frequency of a compressor according to some embodiments;

[0016] FIG. 10 is an example diagram of a polynomial fitting curve between adjustment ratio and discharge superheat of a compressor according to some embodiments;

[0017] FIG. 11 is another example graph of a polynomial fit curve between a modulation ratio and a discharge superheat of a compressor, according to some embodiments;

[0018] FIG. 12 is a block diagram of a controller, according to some embodiments;

[0019] FIG. 13 is a block diagram of a first gas-liquid separator and a second gas-liquid separator, according to some embodiments;

[0020] FIG. 14 is yet another block diagram of an air conditioning system, according to some embodiments;

[0021] FIG. 15 is yet another block diagram of an air conditioning system, according to some embodiments;

[0022] FIG. 16 is a block diagram of another air conditioning system, according to some embodiments;

[0023] FIG. 17 is a refrigerant flow diagram of another air conditioning system in a cooling mode, according to some embodiments;

[0024] FIG. 18 is a refrigerant flow diagram of another air conditioning system in a heating mode, according to some embodiments;

[0025] FIG. 19 is a refrigerant flow diagram of another air conditioning system in a cooling mode with unloading, according to some embodiments;

[0026] FIG. 20 is a refrigerant flow diagram of another air conditioning system in a heating mode with unloading, according to some embodiments;

[0027] FIG. 21 is a partial enlarged view of circle A in FIG. 16, with the auxiliary valve in a non-unloading state;

[0028] FIG. 22 is a partial enlarged view of circle A in FIG. 16, with the auxiliary valve in an unloading state;

[0029] FIG. 23 is a partial enlarged view of circle B in FIG. 16, with the circuit valve in a non-unloading state;

[0030] FIG. 24 is a partial enlarged view of circle B in FIG. 16, with the circuit valve in an unloading state;

[0031] FIG. 25 is a block diagram of yet another air conditioning system, according to some embodiments;

[0032] FIG. 26 is a refrigerant flow diagram of yet another air conditioning system in a cooling mode, according to some embodiments;

[0033] FIG. 27 is a refrigerant flow diagram of yet another air conditioning system in a heating mode, according to some embodiments;

[0034] FIG. 28 is a refrigerant flow diagram for yet another air conditioning system when unloading in cooling mode, according to some embodiments;

[0035] FIG. 29 is a refrigerant flow diagram for yet another air conditioning system when unloading in heating mode, according to some embodiments;

[0036] FIG. 30 is a partial enlarged view of circle C in FIG. 25, with the circuit valve in a non-unloading state;

[0037] FIG. 31 is a partial enlarged view of circle C in FIG. 25, with the circuit valve in an unloading state;

[0038] FIG. 32 is a partial enlarged view of circle D in FIG. 25. DETAILED DESCRIPTION

[0039] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. However, various implementation of the present disclosure can be practiced without the specific details, which are not described in detail, or are intended to be particular to the implementation described herein. In other instances, well-known methods, procedures, components, and networks have not been described in detail as not to unnecessarily obscure pertinent aspects of the implementations.

[0040] Unless otherwise required by context, as used herein and throughout this specification, the term "comprise" and variations of the term, such as "comprises" (third person singular), "comprising" (present participle verb) and "comprise" (third person plural) are to be construed as open-ended, i.e. as "including, but not limited to." In the description of the specification, the terms "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific example" or "some examples" are not necessarily referring to the same embodiment or example. Furthermore, the described features, structures, materials or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0041] Hereinafter, the terms "first", "second", etc. are used only for the purpose of description and should not be construed as indicating or implying relative importance or implying the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0042] In describing some embodiments, "coupled" and "connected," along with their derivatives, can be used. It should be understood that these terms are not intended as synonyms for each other. Rather, "connected" can be used to indicate that two or more elements are in direct physical or electrical contact with each other. "Coupled" can be used to indicate that two or more elements are in either physical or electrical contact with each other, even at a remote location from each other. The term "coupled" as used herein encompasses the case where one or more intervening elements can exist. The embodiments disclosed herein are not necessarily limited to the details of the description.

[0043] "A, B, and C at least one of" has the same meaning as "at least one of A, B, or C," and includes the following combinations: only A, only B, only C, A and B, A and C, B and C, and A and B and C.

[0044] "A and / or B" includes the following combinations: A alone, B alone, and A and B together.

[0045] The use of "adapted to" or "configured to," as used herein, means open and inclusive language that does not exclude additional devices or steps not explicitly described.

[0046] As used herein, "about," "approximately," or "around" includes the recited value and the average value within an acceptable range of deviation from the recited value, as determined by one of ordinary skill in the art considering the measurement in question and the error in measuring the particular quantity (i.e., the limitations of the measurement system).

[0047] As used herein, "parallel," "perpendicular," and "equal" include the recited condition and conditions that approximate the recited condition, the approximation being within an acceptable range of deviation, as determined by one of ordinary skill in the art considering the measurement in question and the error in measuring the particular quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallel and near parallel, where near parallel can be within an acceptable deviation range of, for example, 5°; "perpendicular" includes absolute perpendicular and near perpendicular, where near perpendicular can also be within an acceptable deviation range of, for example, 5°. "Equal" includes absolute equality and near equality, where near equality can be within an acceptable deviation range of, for example, less than or equal to 5% of either of the two quantities being compared.

[0048] With the development of multi-split air conditioning technology and the iteration of market products, the capacity of a single modular unit is getting larger and larger. The capacity of the largest single modular unit currently on the market has exceeded 40 horsepower (HP), and the maximum modular combined capacity has reached 168 HP.

[0049] The installation of a multi-split air conditioning system has the characteristics of high drop and long piping. The maximum installation drop between the outdoor unit and the indoor unit is greater than or equal to 20 m, and the one-way piping between the outdoor unit and the farthest indoor unit is greater than or equal to 60 m. Due to the use of high drop and long piping installation method, the total amount of refrigerant in the multi-split air conditioning system is greatly increased. The refrigerant charge in a large multi-split air conditioning system has reached hundreds of kilograms.

[0050] The capacity of the indoor unit in a multi-split air conditioning system spans a wide range, and the ratio of the total capacity of the indoor unit to the rated capacity of the outdoor unit (i.e., the ratio of the total capacity of the indoor unit to the rated capacity of the outdoor unit) in a multi-split air conditioning system is wide. The capacity of a single indoor unit spans 15 kW to 560 kW, and the ratio of the total capacity of the indoor unit to the rated capacity of the outdoor unit ranges from 30% to 200%.

[0051] The design characteristics of high drop, long piping, and over-proportioning require a large-capacity liquid storage container to be provided in the outdoor unit of a multi-split air conditioning system. However, the liquid storage container of the current multi-split air conditioning system is designed according to a small pressure vessel (standard capacity less than 30 L), which cannot meet the design requirements of large multi-split air conditioning systems.

[0052] A set of parallel gas-liquid separators is usually used in related technologies to solve the above problems. As shown in FIG. 1, the top of the two gas-liquid separators is provided with a gas communication pipe, and the gaseous refrigerant is uniformly distributed in the two gas-liquid separators through the gas communication pipe. The bottom of the two gas-liquid separators is provided with a liquid communication pipe, and the liquid refrigerant is uniformly distributed in the two gas-liquid separators through the liquid communication pipe. The two gas-liquid separators are respectively provided with independent gas inlet pipes and gas return pipes.

[0053] However, since the two gas-liquid separators are respectively connected to a compressor, and the working conditions of the compressor cannot be completely synchronized during the transition stage of the air conditioning system (including start-stop, load change, defrosting, and refrigerant charging stages), it is easy to cause uneven distribution of liquid and gas between the two gas-liquid separators. At this time, only the liquid communication pipe cannot solve this problem.

[0054] In addition, the pressure loss of the air conditioning system on the low-pressure side has five times the impact on the overall air conditioning system than the pressure loss on the high-pressure side, and the pressure loss of the two gas-liquid separators accounts for about 30% of the pressure loss on the low-pressure side. Pressure loss increases the resistance and energy loss of refrigerant flow in the air conditioning system. If the pressure loss increases, the compressor needs to increase the power to provide the refrigeration or heating capacity of the air conditioning system, i.e. more energy is needed to maintain the operation of the air conditioning system, thereby increasing the energy consumption of the air conditioning system.

[0055] It should be noted that the air conditioning load refers to the amount of cooling, heating and humidity required to compensate for the heat lost by the room or maintain the relative humidity in the room to maintain the set temperature in the room.

[0056] Some embodiments of the present disclosure provide an air conditioning system, which is provided with two gas-liquid separators, i.e. a first gas-liquid separator and a second gas-liquid separator. A gas communication pipe is provided at the top of the two parallel gas-liquid separators, so that the gaseous refrigerant can be uniformly distributed in the two gas-liquid separators through the gas communication pipe. The bottom of the first gas-liquid separator is provided with a plurality of liquid branches, and any one of the plurality of liquid branches is connected to a compressor. The arrangement of the liquid branch can guide the oil to return to the compressor, which can reduce the oil content correction coefficient, thereby reducing the pressure loss of the air conditioning system. In addition, the second gas-liquid separator includes a plurality of outlet pipes, and any one of the plurality of outlet pipes is connected to a compressor to guide the gaseous refrigerant to the compressor. The outlet pipe is designed as a straight pipe in the second gas-liquid separator, which further reduces the pressure loss of the gas-liquid separator, thereby reducing the energy consumption of the air conditioning system.

[0057] The present disclosure provides an air conditioning system 100, for example, the air conditioning system 100 is a multi-split air conditioning system.

[0058] The air conditioning system 100 performs a refrigerant cycle of the air conditioning system 100 by using a compressor, a condenser, a throttling device and an evaporator. The refrigerant cycle includes a series of processes involving compression, condensation, expansion and evaporation, and refrigeration or heating of an indoor space.

[0059] From a principle point of view, the low-temperature and low-pressure refrigerant enters the compressor, which compresses the low-temperature and low-pressure refrigerant into a high-temperature and high-pressure refrigerant gas and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant gas into a liquid phase, and the heat of the refrigerant gas is released to the surrounding environment through the condensation process.

[0060] The throttling device expands the high-temperature and high-pressure liquid-phase refrigerant formed in the condenser into low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the throttling device and returns refrigerant gas in a low-temperature and low-pressure state to the compressor. The evaporator can achieve a refrigeration effect by exchanging heat with a material to be cooled using latent heat of evaporation of the refrigerant. Throughout the cycle, the air conditioning system 100 can adjust the temperature of the indoor space.

[0061] In some embodiments, referring to FIGS. 2-6, the air conditioning system 100 includes an outdoor unit 10.

[0062] In some embodiments, the air conditioning system 100 further includes an indoor unit 20. The indoor unit 20 is connected to the outdoor unit 10. The indoor unit 20 can be disposed in an indoor space.

[0063] In some embodiments, the outdoor unit 10 includes at least one compressor. Any of the at least one compressor is configured to compress refrigerant such that low-pressure refrigerant is compressed to form high-pressure refrigerant.

[0064] In some embodiments, the outdoor unit 10 further includes an outdoor heat exchanger 111. The outdoor heat exchanger 111 is configured to exchange heat between outdoor air and refrigerant transferred in the outdoor heat exchanger 111. For example, the outdoor heat exchanger 111 works as a condenser in a refrigeration mode of the air conditioning system 100, such that refrigerant compressed by the compressor is condensed by emitting heat to outdoor air through the outdoor heat exchanger 111. The outdoor heat exchanger 111 works as an evaporator in a heating mode of the air conditioning system 100, such that decompressed refrigerant is evaporated by absorbing heat of outdoor air through the outdoor heat exchanger 111.

[0065] In some embodiments, the outdoor unit 10 further includes a first fan (outdoor fan). The first fan is configured to draw outdoor air into the outdoor unit 10 through an outdoor air inlet of the outdoor unit 10 and send outdoor air exchanged with the outdoor heat exchanger 111 out of the outdoor unit 10 through an outdoor air outlet of the outdoor unit 10. The first fan provides power for the flow of outdoor air.

[0066] The rotation speed of the first fan can be controlled, and the air conditioning system 100 changes the flow of air exchanged with the outdoor heat exchanger 111 by adjusting the rotation speed of the first fan. The first fan can be any optional fan form such as an axial fan, a cross-flow fan, etc. The first fan can be disposed near the outdoor heat exchanger 111.

[0067] In some embodiments, the indoor unit 20 comprises an indoor heat exchanger 201. The indoor heat exchanger 201 is configured to exchange heat between indoor air and refrigerant transmitted in the indoor heat exchanger 201. For example, the indoor heat exchanger 201 works as an evaporator in the cooling mode of the air conditioning system 100, so that the refrigerant, which has released heat via the outdoor heat exchanger 111, evaporates by absorbing heat of the indoor air via the indoor heat exchanger 201. The indoor heat exchanger 201 works as a condenser in the heating mode of the air conditioning system 100, so that the refrigerant, which has absorbed heat via the outdoor heat exchanger 111, condenses by releasing heat to the indoor air via the indoor heat exchanger 201.

[0068] In some embodiments, the indoor unit 20 further comprises a second fan (indoor fan) configured to suck indoor air into the indoor unit 20 via an indoor air inlet of the indoor unit 20, and send indoor air, which has exchanged heat with the indoor heat exchanger 201, out of the indoor unit 20 via an air outlet of the indoor unit 20. The second fan 205 provides power for the flow of the indoor air. The second fan can be arranged near the indoor heat exchanger 201. The second fan can be a fan in the form of an axial fan, a cross-flow fan, etc.

[0069] In some embodiments, the air conditioning system 100 further comprises a throttling device configured to reduce the pressure of the refrigerant flowing therethrough and adjust the circulation flow of the refrigerant. The throttling device can be arranged in at least one of the indoor unit 20 or the outdoor unit 10.

[0070] For example, the outdoor unit 10 further comprises an outdoor throttling device, such as an outdoor expansion valve 112, which is arranged in association with the outdoor heat exchanger 111. The outdoor expansion valve 112 is arranged at one end of the outdoor heat exchanger 111 close to the indoor heat exchanger 201, to adjust the pressure and flow of the refrigerant flowing between the outdoor heat exchanger 111 and the indoor heat exchanger 201.

[0071] The outdoor expansion valve 112 can be an electronic valve. The opening degree of the outdoor expansion valve 112 is adjustable to control the flow and pressure of the refrigerant flowing through the outdoor expansion valve 112.

[0072] For example, the indoor unit 20 further comprises an indoor throttling device, such as an indoor expansion valve 202, which is arranged in association with the indoor heat exchanger 201. The indoor expansion valve 202 is arranged at one end of the indoor heat exchanger 201 close to the outdoor heat exchanger 111, to adjust the pressure and flow of the refrigerant flowing between the outdoor heat exchanger 111 and the indoor heat exchanger 201.

[0073] The indoor expansion valve 202 can be an electronic valve. The opening degree of the indoor expansion valve 202 is adjustable to control the flow and pressure of the refrigerant flowing through the indoor expansion valve 202.

[0074] In some embodiments, the compressor, the outdoor heat exchanger 111, the throttling device and the indoor heat exchanger 201 connected in sequence form a refrigerant circuit in which refrigerant circulates and exchanges heat with air through the outdoor heat exchanger 111 and the indoor heat exchanger 201 respectively to achieve the cooling mode or the heating mode of the air conditioning system 100.

[0075] In some embodiments, the indoor unit 20 and the outdoor unit 10 are connected by pipes to transmit refrigerant.

[0076] In some embodiments, the air conditioning system 100 further comprises a liquid pipe 30 located between the condenser outlet and the inlet end of the expansion valve.

[0077] In some embodiments, the air conditioning system 100 further comprises a gas pipe 40 located between the outlet of the expansion valve and the inlet of the compressor.

[0078] In some embodiments, the outdoor unit 10 and the indoor unit 20 are connected by the liquid pipe 30 and the gas pipe 40 to form a refrigerant circuit so that refrigerant can circulate in the refrigerant circuit.

[0079] It should be noted that in the cooling mode, the liquid pipe 30 of the air conditioning system 100 is high pressure, and the gas pipe 40 of the air conditioning system 100 is low pressure. In the heating mode, the liquid pipe 30 of the air conditioning system 100 is low pressure, and the gas pipe 40 of the air conditioning system 100 is high pressure.

[0080] In some embodiments, the air conditioning system 100 further comprises a liquid pipe stop valve 301 arranged in the liquid pipe 30. The liquid pipe stop valve 301 is configured to control the on-off of the liquid pipe 30.

[0081] In some embodiments, the air conditioning system 100 further comprises a gas pipe stop valve 401 arranged in the gas pipe 40. The gas pipe stop valve 401 is configured to control the on-off of the gas pipe 40.

[0082] In some embodiments, the outdoor unit 10 further comprises a switching valve 110, for example, a four-way valve. The switching valve 110 is connected in the refrigerant circuit and is configured to switch the flow direction of the refrigerant in the refrigerant circuit to make the air conditioning system 100 execute the cooling mode or the heating mode. The switching valve 110 is connected to the outdoor heat exchanger 111, the outdoor heat exchanger 111 is connected to the outdoor expansion valve 112, and the outdoor expansion valve 112 is connected to the liquid pipe stop valve 301.

[0083] The indoor heat exchanger 201 and the outdoor heat exchanger 111 can be used as a condenser or an evaporator. It can be understood that, in a cooling mode, the indoor heat exchanger serves as an evaporator and the outdoor heat exchanger serves as a condenser. The refrigerant cycle in the cooling mode is shown in FIG. 3. In a heating mode, the indoor heat exchanger serves as a condenser and the outdoor heat exchanger serves as an evaporator. The refrigerant cycle in the heating mode is shown in FIG. 4.

[0084] In some embodiments, the indoor unit 20 can adopt a separate air supply structure, such as a wall-mounted air supply structure, a floor-mounted air supply structure, a ducted air supply structure, or an air supply structure embedded in a ceiling, etc. The indoor unit 20 further includes a housing including an air return port for drawing in air and an air supply port for supplying air after heat exchange into an indoor space. The second fan and the indoor heat exchanger 201 are arranged in the housing.

[0085] In some embodiments, the air conditioning system 100 further includes a wire controller arranged correspondingly to the indoor unit 20, which can be fixedly installed on a wall of the indoor space. The wire controller is provided with an operation interface for inputting a set temperature and a running mode, and a display interface for displaying a current temperature of the indoor space, a running state of the air conditioning system 100, and other parameters.

[0086] In some embodiments, the air conditioning system 100 further includes a remote controller arranged correspondingly to the indoor unit 20, which is in communication connection with the indoor unit 20. The remote controller is provided with a key for inputting a set temperature and a running mode, and a display interface for displaying a current temperature of the indoor space and a running state of the air conditioning system 100.

[0087] In some embodiments, the air conditioning system 100 further includes a mobile control terminal arranged correspondingly to the indoor unit, which is in communication connection with the indoor unit 20. The mobile control terminal includes an application interface, through which a user can input a set temperature and a running mode and display a current temperature or a running state of the indoor space.

[0088] In some embodiments, the mobile control terminal can be a computer, a tablet computer, a smart phone, a wearable device, etc.

[0089] In some embodiments, the at least one compressor can include one compressor.

[0090] Referring to FIGS. 2 to 6, the at least one compressor can include two compressors, i.e., a first compressor 101 and a second compressor 102. The first compressor 101 and the second compressor 102 are arranged in parallel.

[0091] In some embodiments, the first compressor 101 and the second compressor 102 each comprise a hermetic structure with an in-built motor. The low-temperature and low-pressure refrigerant enters the first compressor 101 and the second compressor 102, respectively, and the first compressor 101 and the second compressor 102 compress the low-temperature and low-pressure refrigerant into a high-temperature and high-pressure refrigerant gas and discharge it.

[0092] In some embodiments, the first compressor 101 and the second compressor 102 are provided with lubricating oil (refrigerator oil) configured to reduce the friction and wear of the first compressor 101 and the second compressor 102 to ensure the operational reliability of the first compressor 101 and the second compressor 102.

[0093] In some embodiments, the outdoor unit 10 is provided with more compressors and operates in a group working mode.

[0094] The air conditioning system 100 is described below with the first compressor 101 and the second compressor 102 provided in the outdoor unit 10 as an example.

[0095] In some embodiments, the air conditioning system 100 supplies alternating current to the first compressor 101 or the second compressor 102 in the working state through a frequency conversion component. When the output frequency of the frequency conversion component changes, the rotational speed of the motor in the first compressor 101 and the second compressor 102 also changes, thereby adjusting the size of the cooling or heating capacity of the air conditioning system 100.

[0096] In some embodiments, the first compressor 101 and the second compressor 102 have the same capacity and performance, and when the load of the air conditioning system 100 is evenly distributed, the first compressor 101 and the second compressor 102 can operate at the same frequency.

[0097] In some embodiments, the first compressor 101 and the second compressor 102 have the same capacity and performance. One of the first compressor 101 and the second compressor 102 serves as a main compressor, and the other serves as a standby compressor. The main compressor is responsible for meeting the load (such as the cooling capacity, the heating capacity, etc.) of the air conditioning system 100 within a preset range when the air conditioning system 100 is operating, and the standby compressor is in standby state. The standby compressor starts when the load needs to be increased, for example, during the load exceeding the preset range, to provide additional cooling capacity or heating capacity.

[0098] In some embodiments, the first compressor 101 and the second compressor 102 have the same capacity and performance. The air conditioning system 100 alternately sets one of the first compressor 101 and the second compressor 102 as a main compressor and the other as a standby compressor, and switches the main compressor and the standby compressor after a preset interval of time, thereby prolonging the service life and operational stability of the air conditioning system 100.

[0099] In some embodiments, the first compressor 101 and the second compressor 102 have the same capacity and performance. The air conditioning system 100 dynamically adjusts the operating frequency of the two compressors according to the current load demand, so as to improve the energy efficiency of the air conditioning system 100 and the comfort of the supply air temperature.

[0100] For example, the process of dynamically adjusting the operating frequency of the two compressors according to the current load demand of the air conditioning system 100 can be realized by using the algorithm disclosed in the related art, or by analyzing the historical data and current information of the air conditioning system 100, predicting the future load change trend, and generating the operating frequency of the two compressors.

[0101] In this way, the air conditioning system 100 can adjust the compressor frequency in advance to cope with the upcoming load change, thereby avoiding energy efficiency reduction and maintaining system stability. Alternatively, a load balancing strategy can also be adopted to make the two compressors share different parts of the load according to the distribution and working characteristics of the indoor units 20.

[0102] In some embodiments, the air conditioning system 100 further comprises a first sensor 103 disposed at the discharge end of the first compressor 101. The first sensor 103 is configured to detect the discharge temperature of the first compressor 101.

[0103] In some embodiments, the air conditioning system 100 further comprises a second sensor 104 disposed at the discharge end of the second compressor 102. The second sensor 104 is configured to detect the discharge temperature of the second compressor 102.

[0104] In some embodiments, the air conditioning system 100 further comprises a first switch 105 disposed at the discharge end of the first compressor 101. The first switch 105 is configured to monitor the pressure in the air conditioning system 100 and control the opening and closing of the first compressor 101 according to the pressure of the air conditioning system 100.

[0105] In the case where the pressure in the air conditioning system 100 is greater than the set pressure threshold, the first switch 105 will automatically cut off the power supply and stop the operation of the first compressor 101, so as to protect the equipment and components in the air conditioning system 100 from being damaged by high pressure.

[0106] In some embodiments, the air conditioning system 100 further comprises a second switch 106 disposed at the discharge end of the second compressor 102. The second switch 106 is configured to monitor the pressure of the air conditioning system 100 and control the opening and closing of the second compressor 102 according to the pressure of the air conditioning system 100.

[0107] In the event that the pressure in the air conditioning system 100 is greater than a set pressure threshold, the second switch 106 will automatically cut off power and stop the operation of the second compressor 102 to protect the equipment and components in the air conditioning system 100 from damage caused by high pressure.

[0108] The pressure threshold of the first switch 105 and the second switch 106 can be set according to the design parameters and operating conditions of the air conditioning system 100. Once the pressure in the air conditioning system 100 is reduced below the set pressure threshold, the first switch 105 and the second switch 106 will restore power to allow the first compressor 101 or the second compressor 102 to restart.

[0109] In some embodiments, the outdoor unit 10 further comprises a first oil separator 107 connected to the discharge end of the first compressor 101. The first oil separator 107 is configured to separate lubricating oil from refrigerant.

[0110] In some embodiments, the outdoor unit 10 further comprises a second oil separator 108 connected to the discharge end of the second compressor 102. The second oil separator 108 is configured to separate lubricating oil from refrigerant.

[0111] It can be understood that the first compressor 101 and the second compressor 102 require lubricating oil to reduce friction and wear to ensure the reliability of operation, and the lubricating oil will mix with the refrigerant when the first compressor 101 and the second compressor 102 are working. The first oil separator 107 and the second oil separator 108 separate the lubricating oil from the refrigerant by, for example, the principle of physical separation (such as centrifugal force or gravity). The separated lubricating oil is recycled and reused, while the refrigerant continues to flow.

[0112] It should be noted that when a compressor is set, the oil separator also corresponds to only one set.

[0113] In some embodiments, the outdoor unit 10 further comprises a third sensor 109. The refrigerant flowing out of the first oil separator 107 and the second oil separator 108 converges and flows through the third sensor 109. The third sensor 109 is configured to detect the refrigerant pressure on the high pressure side of the compressor, i.e. the discharge end of the compressor.

[0114] In some embodiments, the outdoor unit 10 further comprises an unloading branch 115. The inlet end of the unloading branch 115 is connected to the pipeline after the first oil separator 107 and the second oil separator 108 converge. The outlet end of the unloading branch 115 is connected to the low pressure side of the first compressor 101 and the second compressor 102.

[0115] In some embodiments, the outdoor unit 10 further comprises an unload branch solenoid valve 117 disposed in the unload branch 115. The unload branch solenoid valve 117 is configured to control the opening and closing of the unload branch 115, and to regulate the flow rate of the refrigerant in the unload branch 115.

[0116] In some embodiments, the outdoor unit 10 further comprises a third pressure reducer 116. The third pressure reducer 116 is disposed between the unload branch solenoid valve 117 and the outlet end of the unload branch 115. The third pressure reducer 116 is configured to throttle the refrigerant in the unload branch 115 to reduce the pressure and temperature of the refrigerant.

[0117] In some embodiments, the outdoor unit 10 further comprises a third filter 118 (unload branch filter). The third filter 118 can be disposed between the unload branch solenoid valve 117 and the inlet end of the unload branch 115. The third filter 118 is configured to remove impurities in the refrigerant, thereby preventing the third pressure reducer 116 downstream from being blocked.

[0118] In some embodiments, the third filter 118, the unload branch solenoid valve 117, and the third pressure reducer 116 are connected in series.

[0119] The unload branch 115 is configured to balance the pressure of the air conditioning system 100 by releasing part of the high-pressure refrigerant to the low-pressure side when the pressure on the high-pressure side of the air conditioning system 100 is greater than a preset pressure, thereby protecting the air conditioning system 100. For example, when the pressure on the high-pressure side of the air conditioning system 100 is greater than a preset pressure threshold, the air conditioning system 100 controls the unload branch solenoid valve 117 to open, allowing high-pressure refrigerant to enter the unload branch 115. The high-pressure refrigerant entering the unload branch 115 first passes through the third filter 118 and enters the third pressure reducer 116 after being filtered by the third filter 118. After being throttled by the third pressure reducer 116, the pressure and temperature of the high-pressure refrigerant will decrease.

[0120] As the high-pressure refrigerant is diverted, the pressure and temperature of the high-pressure refrigerant continuously decrease. After the pressure on the high-pressure side decreases to within the preset pressure threshold, the air conditioning system 100 controls the unload branch solenoid valve 117 to close. In this way, the pressure on the high-pressure side is balanced through the operation of the unload branch 115.

[0121] In some embodiments, the outdoor unit 10 further comprises a fourth sensor 119. The fourth sensor 119 is disposed on the low-pressure side of the compressor. The fourth sensor 119 is configured to detect the refrigerant pressure on the low-pressure side of the compressor. For example, on the low-pressure side of the compressor, the switching valve 110 is connected to the inlet pipeline 135. The fourth sensor 119 is disposed at the inlet pipeline 135.

[0122] In some embodiments, the outdoor unit 10 further comprises a first gas-liquid separator 120. The first gas-liquid separator 120 separates the gas and the liquid according to the difference in density. When the refrigerant mixed with the gas and the liquid flows out of the evaporator and enters the first gas-liquid separator 120, the liquid with a larger density will sink to the bottom of the first gas-liquid separator 120 due to the gravity, and the gas with a smaller density will gather at the top of the first gas-liquid separator 120. Thus, the preliminary gas-liquid separation is achieved through the first gas-liquid separator 120.

[0123] It can be understood that the bottom of the gas-liquid separator is the side where the liquid sinks, and the top of the gas-liquid separator is the side where the gas gathers.

[0124] In some embodiments, the outdoor unit 10 further comprises a second gas-liquid separator 121. The second gas-liquid separator 121 is configured to further improve the separation effect. In this way, the gas-liquid separator can separate the liquid refrigerant and the gaseous refrigerant.

[0125] In some embodiments, the outdoor unit 10 further comprises a gas communication pipe 122, the first gas-liquid separator 120 and the second gas-liquid separator 121 are connected through the gas communication pipe 122, the first gas-liquid separator 120 can store the liquid refrigerant, and the second gas-liquid separator 121 can store the gaseous refrigerant.

[0126] In some embodiments, the first gas-liquid separator 120 and the second gas-liquid separator 121 are arranged at the suction side of the compressor, and the first gas-liquid separator 120, the second gas-liquid separator 121 and the suction side of the compressor are connected in sequence, i.e., the second gas-liquid separator 121 is connected to the suction side of the compressor. One of the main functions of the first gas-liquid separator 120 and the second gas-liquid separator 121 is to separate the refrigerant gas and the refrigerant liquid, and to ensure that the liquid entering the suction side of the compressor is within a predetermined range.

[0127] Referring to FIG. 2 and FIG. 13, the first gas-liquid separator 120 comprises a first container 140. The first container 140 is internally formed with a first space configured to store the refrigerant.

[0128] In some embodiments, the first gas-liquid separator 120 further comprises an inlet pipe 135. The inlet pipe 135 is configured to introduce the gaseous refrigerant, the liquid refrigerant and the lubricating oil in the refrigerant circulation into the first space. The inlet pipe 135 is bent after entering the first space, so as to prevent the mixture from flowing back and improve the separation efficiency.

[0129] In some embodiments, the first gas-liquid separator 120 further comprises a plurality of liquid branches, the bottom of the first container 140 is respectively connected to the plurality of liquid branches, and any one of the plurality of liquid branches is connected to one of the plurality of compressors.

[0130] In some embodiments, an auxiliary throttling component is arranged on any of the liquid branch. The auxiliary throttling component is configured to control the on-off of the liquid branch where it is arranged, and to adjust the pressure and flow rate of the refrigerant flowing through the liquid branch.

[0131] In some embodiments, the first gas-liquid separator 120 further comprises an oil return pipe 136 arranged at the bottom of the first container 140.

[0132] For example, the plurality of liquid branches comprises two liquid branches, i.e. a first liquid branch 131 and a second liquid branch 133. The oil return pipe 136 is connected to the first liquid branch 131 and the second liquid branch 133 respectively after being led out from the lower part of the first container 140. The first liquid branch 131 is connected to the first compressor 101, and the second liquid branch 133 is connected to the second compressor 102.

[0133] Of course, in some embodiments, the first liquid branch 131 can be connected to the second compressor 102, and the second liquid branch 133 can be connected to the first compressor 101 (see FIG. 2).

[0134] The first auxiliary throttling component 132 is arranged on the first liquid branch 131, and is configured to control the on-off of the first liquid branch 131, and to adjust the pressure and flow rate of the refrigerant flowing through the first liquid branch 131.

[0135] The second auxiliary throttling component 134 is arranged on the second liquid branch 133, and is configured to control the on-off of the second liquid branch 133, and to adjust the pressure and flow rate of the refrigerant flowing through the second liquid branch 133.

[0136] It should be noted that the design of the oil return pipe 136 and the first liquid branch 131 and the second liquid branch 133 can guide the oil to the compressor, so as to reduce the oil content correction coefficient.

[0137] In some embodiments, the second gas-liquid separator 121 comprises a second container 142. The second container 142 has a second space configured to store refrigerant formed inside.

[0138] In some embodiments, the second gas-liquid separator 121 further comprises a plurality of outlet pipes configured to introduce the gaseous refrigerant entering and stored in the second space through the gas communication pipe 122 into the first compressor 101 and the second compressor 102.

[0139] In some embodiments, the plurality of outlet pipes comprises two outlet pipes, i.e. a first outlet pipe 123 and a second outlet pipe 124.

[0140] The first outlet pipe 123 communicates with the first compressor 101, and is configured to introduce the gaseous refrigerant entering and stored in the second space through the gas communication pipe 122 into the first compressor 101.

[0141] The second outlet pipe 124 communicates with the second compressor 102, and is configured to introduce the gaseous refrigerant entering and stored in the second space through the gas communication pipe 122 into the second compressor 102.

[0142] Of course, in some embodiments, the first outlet pipe 123 can also communicate with the second compressor 102, and the second outlet pipe 124 can communicate with the first compressor 101 (see FIG. 25).

[0143] In some embodiments, the outlet pipe includes a draft tube, which is a straight pipe in the second container 142.

[0144] For example, the first outlet pipe 123 includes a first draft tube 138, and the second outlet pipe 124 includes a second draft tube 139, which are straight pipes in the second container 142.

[0145] It should be noted that the first draft tube 138 and the second draft tube 139 are designed to be straight pipes in the second container 142, so that the diameters of the first draft tube 138 and the second draft tube 139 are equal at different positions inside the draft tubes, and the refrigerant can flow uniformly in the draft tubes, which is beneficial to reduce the pressure loss of the outlet pipe, thereby reducing the pressure loss of the gas-liquid separator.

[0146] Referring to FIGS. 7 to 10, the pressure loss of the gas-liquid separator mainly includes four parts, i.e., the inlet pipe (for example, the inlet pipe 135) pressure loss P1, the outlet pipe (for example, the outlet pipe) pressure loss P2, the sudden expansion pressure loss P3, and the sudden contraction pressure loss P4.

[0147] The inlet pipe pressure loss P1 includes two parts, i.e., the frictional pressure loss P11 and the local pressure loss P12. P1=P11+P12 (Formula 1)

[0148] The frictional pressure loss P11 and the local pressure loss P12 can be represented by the following formulas, respectively.

[0149] λ is the frictional resistance coefficient, ε is the local resistance coefficient, L 进 is the length of the inlet pipe, d 进D is the inner diameter of the inlet pipe, u is the flow velocity in the pipe, p is the density of the liquid mixture entering the gas-liquid separator, and μ is the oil content correction factor. The oil content correction factor is a parameter that corrects for the effect of the oil content in the circulating working fluid (typically refrigerant) in the air conditioning system 100 on the properties of the refrigerant and the performance of the system.

[0150] It can be appreciated that a small amount of oil can be present in the refrigerant circulation loop in the air conditioning system 100, which can come from the lubricating oil of the compressor or from the oil in the air conditioning system 100 outside the compressor. The presence of the oil affects the properties of the refrigerant, such as the density, viscosity, and heat transfer capacity, thereby affecting the performance of the entire air conditioning system 100. The higher the oil content in the refrigeration cycle, the more important the oil content correction factor, which can affect the flow characteristics and pressure loss of the fluid in the pipe. The presence of the oil changes the flow behavior of the refrigerant, which can cause an increase in the viscosity of the fluid, thereby affecting the Reynolds number and the turbulent characteristics of the fluid, causing additional pressure loss and energy consumption.

[0151] The pressure loss P2 of the return pipe also includes two parts, the frictional pressure loss P21 and the local pressure loss P22. P2 = P21 + P22 (Equation 4)

[0152] The frictional pressure loss P21 and the local pressure loss P22 can be represented by the following equations, respectively.

[0153] L 回 D is the inner diameter of the return pipe. 回 D is the inner diameter of the return pipe.

[0154] The sudden expansion pressure loss P3 is represented by the following equation.

[0155] The sudden contraction pressure loss P4 is represented by the following equation.

[0156] A1 is the inlet cross-sectional area of the gas-liquid separator, such as the inlet cross-sectional area of the inlet pipe 135. A2 is the outlet cross-sectional area of the gas-liquid separator, such as the outlet cross-sectional area of the outlet pipe. The sudden expansion pressure loss P3 refers to the pressure loss caused by the sudden decrease in flow velocity when the fluid flows through the sudden expansion portion. This pressure loss is due to the sudden increase in kinetic energy, which leads to a decrease in static pressure. The flow through the sudden expansion portion generates vortexes and turbulence, further increasing the energy loss. Conversely, when the cross-sectional area of the pipe suddenly decreases, the sudden contraction pressure loss is caused by the sudden increase in flow velocity when the fluid flows through the sudden contraction portion. This is due to the sudden decrease in kinetic energy, which leads to an increase in static pressure. The sudden contraction portion also causes vortexes and turbulence, increasing the energy loss. In a multi-split air conditioning system, the cross-sectional area of the pipe changes greatly, so the sudden expansion pressure loss can be taken as 1, and the sudden contraction pressure loss can be taken as 0.5.

[0157] Under the same working conditions, the effects of the inlet pipe pressure loss P1, the return pipe pressure loss P2, the sudden expansion pressure loss P3, and the sudden contraction pressure loss P4 on the overall pressure loss of the gas-liquid separator can be obtained according to the above formula, as shown in FIG. 7. As can be seen from FIG. 7, the return pipe pressure loss P2 accounts for the largest proportion.

[0158] In some embodiments of the present disclosure, the first outlet pipe 123 and the second outlet pipe 124 are designed as straight pipes in the second container 142. In this way, as long as the length of the straight pipe is designed according to the working conditions, the pressure loss of the gas-liquid separator can be reduced while meeting the use conditions of the gas-liquid separator. The design of the oil return pipe 136 and the first liquid branch 131 and the second liquid branch 133 can guide the oil separation back to the compressor, thereby reducing the oil content correction coefficient.

[0159] Referring to Table 1, Table 2, and FIG. 10, in some embodiments, the pipe length, the oil content correction coefficient, and the pressure loss can be reduced, and the reduction rate of the pressure loss of the gas-liquid separator can reach 21%. Table 1 is a comparison table of the pipe length and the oil content correction coefficient of the air conditioning system 100 in some embodiments of the present disclosure and the air conditioning system in the related art. Table 2 is a comparison table of the pressure loss of the air conditioning system in some embodiments of the present disclosure and the air conditioning system in the related art.

[0160] Table 1 Comparison table of pipe length and oil content correction coefficient

[0161] Table 2 Comparison table of pressure loss

[0162] Referring to FIG. 6, in some embodiments, the air conditioning system 100 further includes a controller 50.

[0163] Referring to FIG. 12, the controller 50 includes a processor 501 that can access a storage component to execute instructions or applications stored in the storage component to implement related functions. For example, the processor can be a general-purpose central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), etc.

[0164] In some embodiments, the controller 50 further includes a memory, which can include at least one of a volatile memory 502 or a non-volatile memory 503. The volatile memory 502 has a fast access speed. The non-volatile memory 503 can still save data after power off. The processor 501 can access the memory to execute instructions or applications stored in the memory to implement related functions.

[0165] In some embodiments, the controller 50 further includes a display device 504 configured to display various information of the air conditioning system 100.

[0166] In some embodiments, the controller 50 further includes an operation device 505 configured to receive various operations.

[0167] In some embodiments, the controller 50 further includes a communication interface 506 through which the controller 50 can communicate with external devices.

[0168] The communication interface 506 can include a wireless communication interface that can support different wireless communication protocols, such as wireless fidelity (Wi-Fi), Bluetooth, near field communication, and narrow band internet of things (NB-IoT), etc., to communicate with external devices. Here, the external devices include a cloud server, a computer (host computer), a programmable logic controller, a smart phone, a tablet computer, a PDA, a smart control tool, a wearable device, and a vehicle-mounted device, etc.

[0169] The communication interface 506 can also include a wired communication interface, such as an input / output (I / O) interface, which can be in communication connection with various sensors arranged in the outdoor unit 10 to receive detection values of the various sensors arranged in the outdoor unit 10, such as a pressure sensor arranged at the discharge end of the compressor.

[0170] In some embodiments, the controller 50 further includes a drive device 507, which is a hardware terminal interacting with a storage medium.

[0171] In some embodiments, the controller 50 further includes the above-mentioned components connected to each other through a bus 508.

[0172] In some embodiments, the controller 50 further includes a storage medium, which includes a medium recording information in an optical, electrical or magnetic manner, such as a Compact Disc Read-Only Memory (CD-ROM), a floppy disk, a magneto-optical disk, and the like (as shown as 509 in FIG. 12). The storage medium can also be a semiconductor memory recording information in a point-by-point manner, such as a Read-Only Memory (ROM), a flash memory, and the like (as shown as 510 in FIG. 12).

[0173] In some embodiments, the outdoor unit further includes an outdoor control circuit. The outdoor control circuit is arranged in an electrical box with good sealing performance. The structure of the outdoor control circuit is similar to that of the controller 50, and the outdoor control circuit is configured to drive the first fan and the compressor to work, receive and process sampling signals of connected sensors, and realize the communication function between the outdoor unit 10 and external devices, and the like.

[0174] In some embodiments, the indoor unit 20 further includes an indoor control circuit configured to drive the second fan to work, display various parameters of the air conditioning system 100 on a display interface, realize human-computer interaction, receive and process sampling signals of connected sensors, and realize the communication function between the indoor unit 20 and external devices, and the like.

[0175] In some embodiments, the controller 50 can be integrated into the outdoor control circuit in the outdoor unit 10, for example, the controller 50 is a system-on-chip based on a Microcontroller Unit (MCU).

[0176] It should be noted that in the transition running state of the large multi-split air conditioning system, that is, in the process of switching from one running state to another running state, the fluid flow in the air conditioning system 100 is unstable, which also causes energy loss. For example, in the process of starting the compressor, the fluid circulation and pressure balance need a period of time to establish a stable state, at this time, there can be large pressure fluctuations and liquid inertia in the pipeline, resulting in increased pressure loss and the exhaust temperature is prone to be higher than the preset exhaust temperature threshold. When the load of the air conditioning system 100 changes suddenly, the refrigerant flow and flow rate will also change, and the flow state will also change, for example, the mutual conversion amount of liquid and gas changes or uneven distribution, and the compressor can exceed the preset operating range, resulting in an increase in the exhaust temperature.

[0177] In some embodiments, the controller 50 is configured to, in a case that the exhaust gas superheat of the compressor is greater than the reference exhaust gas superheat and the operating frequency of the compressor satisfies one frequency band condition corresponding to the plurality of transition operating states of the air conditioning system 100, drive the auxiliary throttling component to perform a corresponding action according to the first preset operating parameter of the auxiliary throttling component corresponding to the frequency band condition. The reference exhaust gas superheat is a reference value used to identify whether the exhaust gas superheat of the compressor is too high.

[0178] In some embodiments, the controller 50 is configured to, in a case that the exhaust gas superheat of the first compressor 101 is greater than the reference exhaust gas superheat and the operating frequency of the first compressor 101 satisfies one frequency band condition corresponding to the plurality of transition operating states of the air conditioning system 100, drive the first auxiliary throttling component 132 to perform a corresponding action according to the first preset operating parameter of the auxiliary throttling component corresponding to the frequency band condition.

[0179] In some embodiments, the controller 50 is configured to, in a case that the exhaust gas superheat of the second compressor 102 is greater than the reference exhaust gas superheat and the operating frequency of the second compressor 102 satisfies one frequency band condition corresponding to the plurality of transition operating states of the air conditioning system 100, drive the second auxiliary throttling component 134 to perform a corresponding action according to the first preset operating parameter of the auxiliary throttling component corresponding to the frequency band condition.

[0180] In some embodiments of the present disclosure, the air conditioning system 100 determines whether the air conditioning system 100 is in a transition operating state by identifying the exhaust gas superheat of the compressor and the operating frequency of the compressor. Since the exhaust gas superheat of the compressor is positively correlated with the suction gas amount of the compressor, after determining that the air conditioning system 100 is in an operating state, the controller 50 can control the first auxiliary throttling component 132 and the second auxiliary throttling component 134 to perform corresponding actions to reduce the pressure loss of the air conditioning system 100 in the transition stage, so as to maintain the exhaust gas superheat of the compressor within a preset superheat range. In this way, the stability of the operating state of the compressor and the system performance can be maintained, and the problems of reduced refrigeration efficiency and increased energy consumption can be avoided.

[0181] In the air conditioning system 100 provided by some embodiments of the present disclosure, the first gas-liquid separator 120 and the second gas-liquid separator 121 can realize gas-liquid separation on the one hand, and can reduce the pressure loss and the oil content correction coefficient on the other hand, thereby realizing separation of the oil gas at the low-pressure end of the air conditioning system 100. In addition, the controller 50 drives the operation of the auxiliary throttling component according to the frequency band condition corresponding to the plurality of transition operating states, thereby managing the separated oil gas, so that the air conditioning system 100 can operate efficiently, reliably and stably in different transition operating states, and the refrigeration or heating effect of the air conditioning system 100 is improved.

[0182] In some embodiments, the compressor discharge superheat T dSH1 is calculated by the following equation. dSH1 = T d1 - P dt (Formula 11)

[0183] T d1 is the detected temperature of the first sensor 103, and P dt is the saturated temperature corresponding to the detected pressure of the third sensor 109.

[0184] In some embodiments, the compressor discharge superheat T dSH2 is calculated by the following equation. dSH2 = T d2 - P dt (Formula 12)

[0185] T d2 is the detected temperature of the first sensor 103, and P dt is the saturated temperature corresponding to the detected pressure of the third sensor 109.

[0186] In some embodiments, the reference discharge superheat can be obtained under experimental conditions. For example, the process of obtaining the reference discharge superheat can include the following steps: determining the type and working conditions of the refrigerant used in the air conditioning system 100, including the model of the compressor, the working pressure range, the condensing temperature, and the properties and performance parameters of the refrigerant. Look up the refrigerant table or the pressure-temperature curve to determine the corresponding refrigerant saturation temperature, set a reference discharge superheat, for example, 35°C, according to the calculated refrigerant saturation temperature. Correct the reference discharge superheat according to the working environment, load condition and design parameters of the compressor of the air conditioning system 100.

[0187] In some embodiments, the reference discharge superheat can be obtained by changing at least one of the refrigerant type, the discharge pressure, the condensing temperature, the compressor load, the ambient temperature and the ambient humidity as an action option to perform reinforcement learning.

[0188] In some embodiments, the first preset operating parameter of the auxiliary throttling component corresponding to the frequency band condition includes an adjustment ratio and an adjustment period. The controller 50 is further configured to drive the auxiliary throttling component to be in an open valve state. The current opening degree of the auxiliary throttling component is generated according to the product of the maximum opening degree of the auxiliary throttling component and the adjustment ratio, and the auxiliary throttling component is driven to return to a closed valve state after the corresponding auxiliary throttling component adjustment period ends.

[0189] In some embodiments, the multiple frequency band conditions are sequentially divided according to the high and low of the operating frequency threshold of the compressor in the transition operating state.

[0190] In some embodiments, the transition operation state can include a first transition operation state (low frequency transition operation state) corresponding to a load change, a second transition operation state (medium frequency transition operation state) corresponding to a load change, and a third transition operation state (high frequency transition operation state) corresponding to a load change. It should be noted that the operating frequency of the compressor in the first transition operation state is less than the operating frequency of the compressor in the second transition operation state, and the operating frequency of the compressor in the second transition operation state is less than the operating frequency of the compressor in the third transition operation state.

[0191] In some embodiments, the controller 50 of the air conditioning system 100 in the transition operation state is taken as an example for description. It is assumed that N1 is the operating frequency of the first compressor 101, and N2 is the operating frequency of the second compressor 102. The frequency band condition corresponding to the first transition operation state can be set as 60Hz>N1>0Hz or N2<60Hz, the frequency band condition corresponding to the second transition operation state can be set as 90Hz>N1≥60Hz or 60Hz≤N2<90Hz, and the frequency band condition corresponding to the third transition operation state can be set as N1≥90Hz or N2≥90Hz.

[0192] It can be understood that in the transition operation state, N1 changes from low to high, and N2 changes from high to low. The frequency band condition corresponding to the first transition operation state can be set as N1 increases from 0Hz to N1>0Hz, and N2 decreases from 60Hz or more to N2<60Hz. The frequency band condition corresponding to the second transition operation state can be set as N1 increases from 60Hz or less to N1≥60Hz, and N2 decreases from 90Hz or more to N2<90Hz. The frequency band condition corresponding to the third transition operation state can be set as N1 increases from 90Hz or less to N1≥90Hz, and N2 maintains N2≥90Hz. That is, the frequency band corresponding to the transition operation state is a mutation point, and the energy loss is more likely to occur at the mutation point.

[0193] In some embodiments, the higher the operating frequency threshold of the compressor, the shorter the adjustment period of the auxiliary throttling component corresponding to the frequency band condition.

[0194] In some embodiments, if the first compressor 101 or the second compressor 102 meets the frequency band condition corresponding to the plurality of transition operation states, the controller 50 can set a time interval T, drive the auxiliary throttling component to perform the corresponding action according to the first preset operating parameter of the auxiliary throttling component corresponding to the frequency band condition, and control the auxiliary throttling component to perform the corresponding action for a preset adjustment period.

[0195] For example, if the running frequency of the first compressor 101 or the second compressor 102 meets the frequency band condition corresponding to the first transition running state, the adjustment period can be set as T-Amin. If the running frequency of the first compressor 101 or the second compressor 102 meets the frequency band condition corresponding to the second transition running state, the adjustment period can be set as T-Bmin. If the running frequency of the first compressor 101 or the second compressor 102 meets the frequency band condition corresponding to the third transition running state, the adjustment period can be set as T-Cmin. A, B, C are constants and satisfy A>B>C, for example, 10, 7 and 5 respectively.

[0196] Table 3 Operation parameters of auxiliary throttling device

[0197] It should be noted that the adjustment ratio is generated according to the exhaust superheat of the compressor. In this way, the controller 50 can generate the current opening of the auxiliary throttling component according to the exhaust superheat of the compressor, so as to realize dynamic response adjustment.

[0198] In some embodiments, the controller 50 stores a polynomial fitting curve between the adjustment ratio and the exhaust superheat of the compressor.

[0199] In some embodiments, the controller 50 is further configured to determine the adjustment ratio corresponding to the exhaust superheat of the compressor according to the polynomial fitting curve and the exhaust superheat of the compressor, and generate the current opening of the auxiliary throttling component according to the product of the maximum opening of the auxiliary throttling component and the adjustment ratio.

[0200] FIG. 10 is an example of a polynomial fitting curve between the adjustment ratio and the exhaust superheat of the compressor. The expression of the polynomial fitting curve in FIG. 10 is y=0.0726x 2 -3.3155x+36.429, x is the exhaust superheat T of the compressor dsH , y is the adjustment ratio ΔEV. The current opening of the auxiliary throttling component is the product of the maximum opening and the adjustment ratio.

[0201] In some embodiments, if it is determined that T dSH1 >35 and 60Hz>N1>0Hz, it is determined that the air conditioning system 100 is in the first transition running state, and the controller 50 drives the first auxiliary throttling component 132 to perform the corresponding action at an interval of a set time T. The controller 50 drives the first auxiliary throttling component 132 to be in the open valve state, generates the current opening of the first auxiliary throttling component 132 according to the product of the maximum opening of the first auxiliary throttling component 132 and the adjustment ratio, and the adjustment ratio is obtained according to the polynomial fitting curve. dSH1 According to the polynomial fitting curve.

[0202] Similarly, if it is determined that T dSH2> 35 and N2 < 60 Hz, it is determined that the air conditioning system 100 is in a first transition operating state, at this time, the interval setting time T is set, the second auxiliary throttling component 134 is driven to perform corresponding action, the second auxiliary throttling component 134 is driven to be in an open valve state, a current opening degree of the second auxiliary throttling component 134 is generated according to a product of a maximum opening degree of the second auxiliary throttling component 134 and an adjustment ratio, and the adjustment ratio is adjusted according to T dSH2 The adjustment period can be T-10 min.

[0203] In some embodiments, if it is determined that T dSH1 > 35 and 90 Hz > N1 ≥ 60 Hz, it is determined that the air conditioning system 100 is in a second transition operating state, at this time, the interval setting time T is set, the first auxiliary throttling component 132 is driven to perform corresponding action, the first auxiliary throttling component 132 is driven to be in an open valve state, a current opening degree of the first auxiliary throttling component 132 is generated according to a product of a maximum opening degree of the first auxiliary throttling component 132 and an adjustment ratio, and the adjustment ratio is adjusted according to T dSH1 The adjustment period can be T-10 min.

[0204] Similarly, if it is determined that T dSH2 > 35 and 60 Hz ≤ N2 < 90 Hz, it is determined that the air conditioning system 100 is in a second transition operating state, at this time, the interval setting time T is set, the second auxiliary throttling component 134 is driven to perform corresponding action, the second auxiliary throttling component 134 is driven to be in an open valve state, a current opening degree of the second auxiliary throttling component 134 is generated according to a product of a maximum opening degree of the second auxiliary throttling component 134 and an adjustment ratio, and the adjustment ratio is adjusted according to T dSH2 The adjustment period can be T-7 min.

[0205] In some embodiments, if it is determined that T dSH1 > 35 and N1 ≥ 90 Hz, it is determined that the air conditioning system 100 is in a third transition operating state, at this time, the interval setting time T is set, the first auxiliary throttling component 132 is driven to perform corresponding action, the first auxiliary throttling component 132 is driven to be in an open valve state, a current opening degree of the first auxiliary throttling component 132 is generated according to a product of a maximum opening degree of the first auxiliary throttling component 132 and an adjustment ratio, and the adjustment ratio is adjusted according to T dSH1 The adjustment period can be T-10 min.

[0206] Similarly, if it is determined that T dSH2>35and N2≥ 90 Hz, it is determined that the air conditioning system 100 is in the third transition operating state, at this time, the interval setting time T is set, the second auxiliary throttling component 134 is driven to perform the corresponding action, the second auxiliary throttling component 134 is driven to be in the open valve state, the current opening degree of the second auxiliary throttling component 134 is generated according to the product of the maximum opening degree of the second auxiliary throttling component 134 and the adjustment ratio, and the adjustment ratio is adjusted according to T dSH2 The length of the adjustment period can be T-5 min.

[0207] In some embodiments, the outdoor unit 10 further comprises a plurality of oil return branches. The oil return branches are respectively connected to the oil separators and the liquid branches. An oil return adjusting component is arranged on any of the plurality of oil return branches. The oil return adjusting component is configured to adjust the pressure and flow of the refrigerant flowing through the oil return branch.

[0208] In some embodiments, the outlet pipeline further comprises a communication pipe section, the communication pipe section is arranged outside the second container 142, the oil return branch, the liquid branch and the communication pipe section of the outlet pipeline converge and are connected to the compressor. The first end of the communication pipe section communicates with the drainage pipe, and the second end of the communication pipe section communicates with a compressor.

[0209] For example, the plurality of oil return branches comprises two oil return branches, i.e. a first oil return branch 125 and a second oil return branch 128. The first oil return branch 125 is connected to the first oil separator 107 and the first liquid branch 131. The second oil return branch 128 is connected to the second oil separator 108 and the second liquid branch 133.

[0210] Of course, the first oil return branch 125 can also be arranged between the second oil separator 108 and the second liquid branch 133. The second oil return branch 128 can also be arranged between the first oil separator 107 and the first liquid branch 131.

[0211] In some embodiments, the first oil return branch 125 is provided with a first oil return adjusting component 141. The second oil return branch 128 is provided with a second oil return adjusting component 137.

[0212] It can be understood that the first oil return branch 125 and the second oil return branch 128 can help to balance the distribution of lubricating oil in the air conditioning system 100, so as to ensure that the separated lubricating oil can continuously return to the gas-liquid separator from the oil separator, and then return to the compressor, so as to maintain the lubrication of the compressor.

[0213] In some embodiments, the outdoor unit 10 further comprises a first pressure reducer 126, which is arranged in the first oil return branch 125. For example, the first pressure reducer 126 is arranged in conjunction with the first oil separator 107, i.e. the first pressure reducer 126 is connected between the first compressor 101 and the first oil separator 107.

[0214] In some embodiments, the outdoor unit 10 further comprises a second pressure reducer 130, which is arranged in the second oil return branch 128. For example, the second pressure reducer 130 is arranged in cooperation with the second oil separator 108, i.e. the second pressure reducer 130 is connected between the second compressor 102 and the second oil separator 108.

[0215] The first pressure reducer 126 and the second pressure reducer 130 recycle and guide the deposited lubricating oil into the lubricating system of the first compressor 101 and the second compressor 102 by the principle of adsorption and guidance, so as to realize the recycling use of the lubricating oil in the air conditioning system 100.

[0216] By arranging the first pressure reducer 126 and the second pressure reducer 130, the oil separator located at the high-pressure side and the gas-liquid separator located at the low-pressure side can maintain a stable pressure difference, so that the lubricating oil can smoothly flow from the first oil separator 107 and the second oil separator 108 to the first gas-liquid separator 120 through the first oil return branch 125 and the second oil return branch 128, and the liquid mixture can also be prevented from entering the first gas-liquid separator 120, thereby ensuring the operation reliability of the air conditioning system 100.

[0217] In some embodiments, the outdoor unit 10 further comprises a first filter 127 (first oil return branch filter). The first filter 127 is arranged in the first oil return branch 125.

[0218] In some embodiments, the outdoor unit 10 further comprises a second filter 129 (second oil return branch filter). The second filter 129 is arranged in the second oil return branch 128.

[0219] It can be understood that the first filter 127 and the second filter 129 can filter small-particle impurities to prevent the impurities from entering the gas-liquid separator and the compressor.

[0220] In some embodiments, the first outlet pipeline 123 comprises a first communication pipe section 175, which is arranged outside the second container 142. The refrigerant in the first oil return branch 125, the first liquid branch 131 and the first communication pipe section 175 of the first outlet pipeline 123 can flow together to the first compressor 101.

[0221] In some embodiments, the second outlet pipeline 124 comprises a second communication pipe section 176, which is arranged outside the second container 142. The refrigerant in the second oil return branch 128, the second liquid branch 133 and the second communication pipe section 176 of the second outlet pipeline 124 can flow together to the second compressor 102.

[0222] Referring to FIG. 9, the compressor oil discharge rate is positively correlated with the compressor frequency, i.e., the higher the compressor frequency, the greater the oil discharge rate. When the compressor is running, the oil discharge rate is greater than 0. The compressor discharges oil from the compressor oil pool into the air conditioning system 100, and part of the oil will be retained in the pipeline and the heat exchanger.

[0223] In some embodiments, the controller is further configured to, in a case where the operating frequency of the compressor meets a frequency band condition corresponding to a plurality of transition operating states, drive the oil return adjusting component to perform an action corresponding to a second preset operating parameter of the oil return adjusting component according to the second preset operating parameter of the oil return adjusting component corresponding to the frequency band condition.

[0224] In some embodiments, the second preset operating parameter of the oil return adjusting component corresponding to the frequency band condition includes driving the oil return adjusting component to be in an open valve state. The oil return adjusting component is kept in the open valve state until the end of the corresponding oil return adjusting component adjustment period, and then the oil return adjusting component is driven to return to a closed valve state.

[0225] In some embodiments, the higher the operating frequency threshold of the compressor corresponding to the frequency band condition, the longer the adjustment period of the oil return adjusting component corresponding to the frequency band condition.

[0226] For example, the frequency band condition corresponding to the first transition operating state can be set as 35Hz>N1>0Hz or N2<35Hz. The frequency band condition corresponding to the second transition operating state can be set as N1≥35Hz or 35Hz≤N2<60Hz. The frequency band condition corresponding to the third transition operating state can be set as 95Hz>N1≥60Hz or 60Hz≤N2<95Hz. The frequency band condition corresponding to the fourth transition operating state can be set as N1≥95Hz or N2≥95Hz.

[0227] In some embodiments, in a case where the first compressor 101 or the second compressor 102 meets the frequency band condition corresponding to the first transition operating state, the controller 50 can drive the oil return adjusting component to perform the corresponding action according to the second preset operating parameter of the oil return adjusting component corresponding to the frequency band condition at an interval of a set time T, and control the oil return adjusting component to perform the corresponding action for a preset adjustment period.

[0228] For example, if it is determined that the operating frequency of the first compressor 101 or the second compressor 102 meets the frequency band condition corresponding to the first transition operating state, the adjustment period can be set as T+Dmin.

[0229] If it is determined that the operating frequency of the first compressor 101 or the second compressor 102 meets the frequency band condition corresponding to the second transition operating state, the adjustment period can be set as T+Emin.

[0230] If it is determined that the operating frequency of the first compressor 101 or the second compressor 102 meets the frequency band condition corresponding to the third transition operating state, the adjustment period can be set as T+Fmin.

[0231] If it is determined that the operating frequency of the first compressor 101 or the second compressor 102 meets the frequency band condition corresponding to the fourth transition operating state, the adjustment period can be set as GXT.

[0232] Table 4 Operating parameters of the oil return adjustment component

[0233] In some embodiments, if it is determined that 35Hz>N1>0Hz, the interval setting time T is set, the first oil return adjustment component 141 is driven to be in the open valve state, the first oil return adjustment component 141 is kept in the open valve state, and after the corresponding adjustment component adjustment period ends, the first oil return adjustment component 141 is driven to return to the closed valve state. If it is determined that N2<35Hz, the interval setting time T is set, the second oil return adjustment component 137 is driven to be in the open valve state, the second oil return adjustment component 137 is kept in the open valve state, and after the corresponding adjustment component adjustment period ends, the second oil return adjustment component 137 is driven to return to the closed valve state. The length of the adjustment period is T+1min.

[0234] In some embodiments, if it is determined that N1>35Hz, the interval setting time T is set, the first oil return adjustment component 141 is driven to be in the open valve state, the first oil return adjustment component 141 is kept in the open valve state, and after the corresponding adjustment component adjustment period ends, the first oil return adjustment component 141 is driven to return to the closed valve state. If it is determined that N2<60Hz, the interval setting time T is set, the second oil return adjustment component 137 is driven to be in the open valve state, the second oil return adjustment component 137 is kept in the open valve state, and after the corresponding adjustment component adjustment period ends, the second oil return adjustment component 137 is driven to return to the closed valve state. The length of the adjustment period is T+3min.

[0235] In some embodiments, if it is determined that N1>60Hz, the interval setting time T is set, the first oil return adjustment component 141 is driven to be in the open valve state, the first oil return adjustment component 141 is kept in the open valve state, and after the corresponding adjustment component adjustment period ends, the first oil return adjustment component 141 is driven to return to the closed valve state. If it is determined that N2<95Hz, the interval setting time T is set, the second oil return adjustment component 137 is driven to be in the open valve state, the second oil return adjustment component 137 is kept in the open valve state, and after the corresponding adjustment component adjustment period ends, the second oil return adjustment component 137 is driven to return to the closed valve state. The length of the adjustment period is T+5min.

[0236] In some embodiments, if it is determined that N1≥ 95 Hz, the interval setting time T is set, the first oil return adjusting component 141 is driven to be in the open valve state, the first oil return adjusting component 141 is kept in the open valve state, and after the corresponding adjusting component adjusting period ends, the first oil return adjusting component 141 is driven to return to the closed valve state. If it is determined that N2≥ 95 Hz, the interval setting time T is set, the second oil return adjusting component 137 is driven to be in the open valve state, the second oil return adjusting component 137 is kept in the open valve state, and after the corresponding adjusting component adjusting period ends, the second oil return adjusting component 137 is driven to return to the closed valve state. The length of the adjusting period is 1.5T.

[0237] In some embodiments, as shown in FIGS. 14 and 15, the air conditioning system 100 includes at least two outdoor units 10, for example, the air conditioning system 100 includes two outdoor units 10, which are a first outdoor unit 11 and a second outdoor unit 12, respectively. The first outdoor unit 11 and the second outdoor unit 12 are the same in structure.

[0238] The controller 50 is further configured to, in a case where the discharge superheat of the compressor of any one of the at least two outdoor units 10 is greater than the oil equalization discharge superheat, and the operating frequency of the compressor meets a preset load frequency band condition, drive the auxiliary throttling component to perform a corresponding action according to a first preset operating parameter of the auxiliary throttling component corresponding to the preset load frequency band condition. The oil equalization discharge superheat is a reference value configured to identify whether the refrigeration capacity of the refrigeration system is relatively excessive.

[0239] It should be noted that the preset load frequency band condition here is a low load frequency band condition.

[0240] In some embodiments, the third preset operating parameter of the auxiliary throttling component corresponding to the low load frequency band condition includes an adjusting ratio and an adjusting period.

[0241] The controller 50 is further configured to drive the auxiliary throttling component to be in the open valve state. A current opening degree of the auxiliary throttling component is generated according to the product of the maximum opening degree of the auxiliary throttling component and the adjusting ratio, and after the corresponding auxiliary throttling component adjusting period ends, the auxiliary throttling component is driven to return to the closed valve state. The adjusting ratio is generated according to the discharge superheat of the compressor.

[0242] In some embodiments, the oil equalization discharge superheat is less than a reference discharge superheat. For example, the oil equalization discharge superheat is 25, and the reference discharge superheat is 35.

[0243] In some embodiments, the frequency threshold corresponding to the condition of the low load frequency band is lower than the frequency threshold corresponding to the frequency band condition corresponding to the low frequency transition operating state, for example, 30 Hz.

[0244] In some embodiments, the controller 50 stores a polynomial fitting curve between the adjustment ratio and the discharge superheat of the compressor.

[0245] The controller 50 is further configured to determine, according to the polynomial fitting curve, the adjustment ratio corresponding to the discharge superheat of the compressor according to the discharge superheat of the compressor, and generate the current opening degree of the auxiliary throttling component according to the product of the maximum opening degree of the auxiliary throttling component and the adjustment ratio.

[0246] In some embodiments, if it is determined that T dSH1 > 25 and N1 < N Hz , the controller 50 drives the first auxiliary throttling component 132 to perform the corresponding action at intervals of the set time T, drives the first auxiliary throttling component 132 to be in the open valve state, generates the current opening degree of the first auxiliary throttling component 132 according to the product of the maximum opening degree of the first auxiliary throttling component 132 and the adjustment ratio, and the adjustment ratio is obtained according to the low-load condition polynomial fitting curve. dSH1

[0247] If it is determined that T dSH2 > 25 and N2 < N Hz , the controller 50 drives the second auxiliary throttling component 134 to perform the corresponding action at intervals of the set time T, drives the second auxiliary throttling component 134 to be in the open valve state, generates the current opening degree of the second auxiliary throttling component 134 according to the product of the maximum opening degree of the second auxiliary throttling component 134 and the adjustment ratio, and the adjustment ratio is obtained according to the low-load condition polynomial fitting curve. dSH2

[0248] FIG. 11 is an example of a polynomial fitting curve between the adjustment ratio and the discharge superheat of the compressor in a low-load condition. The expression of the polynomial fitting curve is y = 0.0355x 2 -1.8049x + 31.133, x is the discharge superheat TdsH of the compressor, and y is the adjustment ratio ΔEV. The current opening degree of the auxiliary throttling component is the product of the maximum opening degree and the adjustment ratio.

[0249] Some embodiments of the present disclosure can improve the oil distribution uniformity of the entire air conditioning system 100 by adjusting the first auxiliary throttling component 132 and the second auxiliary throttling component 134, so as to improve the operation stability of the air conditioning system 100.

[0250] Some embodiments of the present disclosure also provide another air conditioning system 100, which improves the unloading branch 115, as shown in FIGS. 16 to 24. ​​

[0251] In some embodiments, referring to FIG. 16, the air conditioning system 100 includes four indoor units, which are respectively shown as a first indoor unit 21, a second indoor unit 22, a third indoor unit 23, and a fourth indoor unit 24. The indoor heat exchanger is provided in correspondence with the indoor expansion valve. For example, the first indoor unit 21 includes a first sub-heat exchanger 211 and a first sub-expansion valve 212. The second indoor unit 22 includes a second sub-heat exchanger 221 and a second sub-expansion valve 222. The third indoor unit 23 includes a third sub-heat exchanger 231 and a third sub-expansion valve 232. The fourth indoor unit 24 includes a fourth sub-heat exchanger 241 and a fourth sub-expansion valve 242.

[0252] It should be noted that this is only an example, and more or fewer indoor units can be included in an air conditioning system 100.

[0253] In some embodiments, a first one-way valve 173 is provided downstream of the first oil separator 107 (i.e., away from the compressor side), and a second one-way valve 174 is provided downstream of the second oil separator 108 (i.e., away from the compressor side). In this way, the refrigerant is prevented from flowing back to the compressor.

[0254] In some embodiments, the outdoor unit 10 further includes a sub-cooler 151. The sub-cooler 151 is configured to separate a portion of the high-temperature and high-pressure liquid refrigerant in the liquid pipe 30. By adjusting the opening degree of the auxiliary valve 153, the temperature and pressure of the separated refrigerant can be controlled, so that the separated refrigerant exchanges heat with the refrigerant in the main pipe. In this way, the heat exchange efficiency of the refrigerant is improved, and the energy consumption of the entire air conditioning system 100 is saved.

[0255] In some embodiments, the outdoor unit 10 further includes a main pipe, one end of the main pipe being connected to the outdoor heat exchanger 111, and the other end of the main pipe being connected to the liquid pipe 30, i.e., being arranged across the liquid side pipe of the outdoor heat exchanger 111 and the liquid pipe 30.

[0256] In some embodiments, the outdoor unit 10 further includes an auxiliary pipe 152, a first end of the auxiliary pipe 152 being connected to the outdoor heat exchanger 111, and a second end of the auxiliary pipe 152 being connected to the suction side of the compressor. That is, the first end of the auxiliary pipe 152 is connected to the liquid side pipe of the outdoor heat exchanger 111, and the second end of the auxiliary pipe 152 is connected to the suction side of the compressor. For example, the second end of the auxiliary pipe 152 is connected to a gas-liquid separator located at the suction side of the compressor. The main pipe and the auxiliary pipe 152 are arranged in parallel adjacent to each other.

[0257] In some embodiments, the main pipe and the auxiliary pipe 152 are arranged in parallel adjacent to each other. Here, the parallel adjacent arrangement can be understood as that the main pipe and the auxiliary pipe 152 are connected in parallel.

[0258] In some embodiments, the auxiliary pipeline 152 is provided with an auxiliary valve 153. The auxiliary valve 153 is selected from valves having the same function, such as an expansion valve.

[0259] In some embodiments, the top portions of the first gas-liquid separator 120 and the second gas-liquid separator 121 are connected by a gas communication pipe 122, i.e., one end of the gas communication pipe 122 is connected to the upper portion of the first gas-liquid separator 120, and the other end is connected to the upper portion of the second gas-liquid separator 121.

[0260] In some embodiments, the bottom portions of the first gas-liquid separator 120 and the second gas-liquid separator 121 are connected by a liquid communication pipe 171, i.e., one end of the liquid communication pipe 171 is connected to the bottom portion of the first gas-liquid separator 120, and the other end is connected to the bottom portion of the second gas-liquid separator 121. The liquid communication pipe 171 is provided with a loop valve 172.

[0261] In some embodiments, the auxiliary pipeline 152 communicates with the first gas-liquid separator 120. For example, the auxiliary pipeline 152 extends into the first gas-liquid separator 120.

[0262] In some embodiments, the second gas-liquid separator 121 is provided with a first drainage pipe 138 and a second drainage pipe 139. The first drainage pipe 138 communicates with the first compressor 101, and the second drainage pipe 139 communicates with the second compressor 102.

[0263] In some embodiments, in order to avoid uneven distribution of lubricating oil in the first compressor 101 and the second compressor 102, the first drainage pipe 138 and the second drainage pipe 139 have the same pipe length in the second gas-liquid separator 121, i.e., the lengths of the first drainage pipe 138 and the second drainage pipe 139 in the second container are equal.

[0264] For example, two identical straight pipes can be selected as the first drainage pipe 138 and the second drainage pipe 139. The first drainage pipe 138 and the second drainage pipe 139 are short straight pipes. One end of the first drainage pipe 138 communicates with the suction side of the first compressor 101. At least one oil return hole can be formed in the vertical pipe section of the first drainage pipe 138. For example, the at least one oil return hole is formed in the bottom portion of the first drainage pipe 138, or in the vertical pipe section away from the suction side of the first compressor 101. One end of the second drainage pipe 139 communicates with the suction side of the second compressor 102. Similarly, at least one oil return hole can be formed in the vertical pipe section of the second drainage pipe 139, for example, the at least one oil return hole is formed in the bottom portion of the second drainage pipe 139, or in the vertical pipe section away from the suction side of the second compressor 102.

[0265] The gaseous refrigerant separated by the first gas-liquid separator 120 is gathered in the upper space of the second gas-liquid separator 121, and can enter the first and second flow guide pipes 138 and 139, and then flow to the suction sides of the first and second compressors 101 and 102, respectively. Due to the small density of the gaseous refrigerant, the pressure difference generated in the suction process of the first and second compressors 101 and 102 can allow the gaseous refrigerant to smoothly enter the first and second compressors 101 and 102.

[0266] When the circuit valve 172 is in the open state, the liquid mixture containing lubricating oil also enters and deposits at the bottom of the second gas-liquid separator 121. The liquid mixture can enter the first and second flow guide pipes 138 and 139 through the oil return holes provided on the vertical pipe sections of the first and second flow guide pipes 138 and 139. As the first and second compressors 101 and 102 continue to suck, the gaseous refrigerant in the first and second flow guide pipes 138 and 139 is continuously sucked, forming a negative pressure, and eventually allowing part of the liquid mixture to return to the first and second compressors 101 and 102, ensuring the reliability of the operation of the first and second compressors 101 and 102.

[0267] In some embodiments, the circuit valve 172 is selected as an expansion valve, which can adjust the opening degree of the circuit valve 172 according to the liquid level height of the first and second gas-liquid separators 120 and 121.

[0268] Referring to FIG. 17, in the refrigeration operation, the outdoor unit can form a refrigerant circuit configured for refrigeration operation, and two parallel branches are connected in sequence from the gas pipe 40 to the liquid pipe 30: the switching valve 110 (e.g., one passage of a four-way valve), the first gas-liquid separator 120, the first compressor 101, the switching valve 110 (e.g., another passage of the four-way valve), the outdoor heat exchanger 111, the outdoor expansion valve 112, and the subcooler 151. The switching valve 110 (e.g., one passage of a four-way valve), the second gas-liquid separator 121, the second compressor 102, the switching valve 110 (e.g., another passage of the four-way valve), the outdoor heat exchanger 111, the outdoor expansion valve 112, and the subcooler 151.

[0269] Referring to FIG. 18, in the heating operation, the outdoor unit can form a refrigerant circuit configured for the heating operation, and two parallel branches are connected in order from the liquid pipe 30 to the gas pipe 40: the subcooler 151, the outdoor expansion valve 112, the outdoor heat exchanger 111, the switching valve 110 (for example, one passage of a four-way valve), the first gas-liquid separator 120, the first compressor 101, and the switching valve 110 (for example, the other passage of the four-way valve). The subcooler 151, the outdoor expansion valve 112, the outdoor heat exchanger 111, the switching valve 110 (for example, one passage of a four-way valve), the second gas-liquid separator 121, the second compressor 102, and the switching valve 110 (for example, the other passage of the four-way valve).

[0270] In the cooling mode, the discharge sides of the first and second compressors 101 and 102 are connected to one end of the outdoor heat exchanger 111 via a four-way valve or the like, and the suction sides of the first and second compressors 101 and 102 are connected to one end of the indoor heat exchangers (211, 221, 231, and 241) via a four-way valve or the like, whereby the outdoor heat exchanger 111 functions as a condenser, and the indoor heat exchangers (211, 221, 231, and 241) function as evaporators.

[0271] Similarly, in the heating mode, the discharge sides of the first and second compressors 101 and 102 are connected to one end of the indoor heat exchangers (211, 221, 231, and 241) via a four-way valve or the like, and the suction sides of the first and second compressors 101 and 102 are connected to one side of the outdoor heat exchanger 111 via a four-way valve or the like, whereby the indoor heat exchangers (211, 221, 231, and 241) function as condensers, and the outdoor heat exchanger 111 functions as an evaporator.

[0272] Due to the large amount of refrigerant charge, the wide range of operating temperatures (in cooling mode, in the range of -10°C to 55°C, in heating mode, in the range of -25°C to 30°C), and the need to adjust a wide range of operating load (minimum load 1.5kW, maximum load up to 1.5 times the capacity of the outdoor unit), the multi-split air conditioning system may have an abnormally high pressure problem during operation. Some embodiments of the present disclosure can solve this problem by setting the auxiliary valve 153 and the first gas-liquid separator 120. The auxiliary valve 153 is in the full open state, and the refrigerant is guided into the first gas-liquid separator 120 through the auxiliary pipeline 152, avoiding unloading through gaseous refrigerant, while ensuring the stable operation of the air conditioning system 100, reducing system noise. At the same time, the system pressure between the first one-way valve 173 and the exhaust side of the first compressor 101, and the system pressure between the second one-way valve 174 and the exhaust side of the second compressor 102, can be unloaded to the first gas-liquid separator 120 through the first oil separator 107 and the first pressure reducer 126, and the second oil separator 108 and the second pressure reducer 130, respectively.

[0273] Referring to FIG. 22, in cooling mode, the auxiliary valve 153 can be in the full open state, and the liquid refrigerant is unloaded to the first gas-liquid separator 120 through the auxiliary pipeline 152 of the subcooler 151, and the unloading of the system and the temporary storage of the refrigerant are realized through the first gas-liquid separator 120.

[0274] In some embodiments, the controller 50 can drive the auxiliary valve 153 to be in the full open state during the start-up phase of the cooling mode, and unload a part of the liquid refrigerant to the first gas-liquid separator 120 through the auxiliary pipeline 152 of the subcooler 151, and realize the unloading of the system and the temporary storage of the refrigerant through the first gas-liquid separator 120.

[0275] In some embodiments, the auxiliary valve 153 can be driven to be in the full open state when the compressor discharge pressure is greater than the set pressure in the cooling mode, and a part of the liquid refrigerant is unloaded to the first gas-liquid separator 120 through the auxiliary pipeline 152 of the subcooler 151, and the unloading of the system and the temporary storage of the refrigerant are realized through the first gas-liquid separator 120.

[0276] The comparison between the compressor discharge pressure and the set pressure can be realized by a comparator circuit, or by two I / O ports of a processor. For example, when a comparator circuit is used, the compressor discharge pressure can be converted into an electrical signal and input to one input terminal of the comparator circuit, and the set pressure can be converted into an electrical signal and input to the other input terminal of the comparator circuit, then when the compressor discharge pressure is greater than the set pressure, the comparator circuit can output an active level signal to drive the auxiliary valve 153 to be in the full open state.

[0277] Similarly, in the heating mode, the auxiliary valve 153 can be in the fully open state, and a portion of the liquid refrigerant is unloaded to the first gas-liquid separator 120 through the auxiliary pipeline 152 of the sub-cooler 151, and the system is unloaded and the refrigerant is temporarily stored through the first gas-liquid separator 120.

[0278] In some embodiments, the auxiliary valve 153 can be driven to be in the fully open state when the compressor discharge pressure is greater than the set pressure in the heating mode, and a portion of the liquid refrigerant is unloaded to the first gas-liquid separator 120 through the auxiliary pipeline 152 of the sub-cooler 151, and the system is unloaded and the refrigerant is temporarily stored through the first gas-liquid separator 120.

[0279] The comparison between the compressor discharge pressure and the set pressure can also be realized by a comparator circuit, or by two I / O ports of a processor.

[0280] During the unloading process, the second gas-liquid separator 121 can play a buffering role, and can avoid a large amount of liquid entering the compressor to cause liquid hammer. In some embodiments, the circuit valve 172 is in the fully closed state when the auxiliary valve 153 is driven to be in the fully open state. That is, the auxiliary valve 153 is in the fully open state, and the circuit valve 172 is in the fully closed state, and the refrigerant is guided into the first gas-liquid separator 120 through the auxiliary pipeline 152.

[0281] In some embodiments, the auxiliary valve 153 is driven to exit the fully open state after the start-up phase of the cooling mode and the heating mode ends. The auxiliary valve 153 after exiting the fully open state can be controlled according to the control algorithm used in the related art, which will not be described here.

[0282] In some embodiments, the auxiliary valve 153 is driven to exit the fully open state when the compressor discharge pressure is less than or equal to the set pressure in the cooling mode. For example, when the comparator circuit is used to compare the compressor discharge pressure and the set pressure, the comparator circuit stops outputting the valid level signal when the compressor discharge pressure is less than or equal to the set pressure, and the auxiliary valve 153 is driven to exit the fully open state. The valid level signal can be one of a high level signal and a low level signal.

[0283] In some embodiments, the circuit valve 172 is driven to exit the fully closed state after the start-up phase of the cooling mode and the heating mode ends. The circuit valve 172 after exiting the fully closed state can be controlled according to the control algorithm used in the related art, which will not be described here.

[0284] In some embodiments, the drive circuit valve 172134 exits the fully closed state when the refrigeration mode is on and the compressor discharge pressure is less than or equal to the set pressure. For example, when a comparator circuit is used to compare the compressor discharge pressure and the set pressure, the comparator circuit stops outputting a valid level signal when the compressor discharge pressure is less than or equal to the set pressure, and the drive circuit valve 172134 exits the fully closed state.

[0285] After the circuit valve 172 exits the fully closed state, the liquid mixture flows more smoothly through the liquid communication pipe 171, and gradually reaches a liquid level balance between the first gas-liquid separator 120 and the second gas-liquid separator 121.

[0286] Some embodiments of the present disclosure also provide yet another air conditioning system 100 that includes both a liquid branch and an oil return branch, and an improved unloading component.

[0287] In some embodiments, the first gas-liquid separator 120 is connected to the compressor through a liquid branch. The first gas-liquid separator 120 is connected to the first compressor 101 through a first liquid branch 131, and is connected to the second compressor 102 through a second liquid branch 133.

[0288] In some embodiments, the second gas-liquid separator includes a draft tube. The draft tube includes a straight pipe section that is arranged in the second gas-liquid separator and extends outward from the second gas-liquid separator and is connected to the suction side of the compressor.

[0289] In some embodiments, the liquid branch is connected to the first gas-liquid separator and the draft tube, and an auxiliary throttling component is arranged on the liquid branch.

[0290] In some embodiments, the first liquid branch 131 is connected to the first gas-liquid separator 120 and the first draft tube 138, and the second liquid branch 133 is connected to the second gas-liquid separator 121 and the second draft tube 139. A first auxiliary throttling component 132 is arranged on the first liquid branch 131, and a second auxiliary throttling component 134 is arranged on the second liquid branch 133.

[0291] In some embodiments, an oil separator is connected to the compressor and the draft tube, respectively. An oil return adjusting component is arranged between the oil separator and the draft tube.

[0292] In some embodiments, the first oil separator 107 is connected to the first compressor 101 and the first draft tube 138, respectively, and the second oil separator 108 is connected to the second compressor 102 and the second draft tube 139, respectively. A first oil return adjusting component 141 is arranged between the first oil separator 107 and the first draft tube 138, and a second oil return adjusting component 137 is arranged between the second oil separator 108 and the second draft tube 139.

[0293] During the unloading process, the second gas-liquid separator 121 can act as a buffer, which can avoid a large amount of liquid entering the compressor to cause liquid hammer.

[0294] In some embodiments, during the unloading process, the controller 50 drives the auxiliary valve 153 to be in the fully open state, and drives the auxiliary throttling components to be in the fully closed state. That is, the auxiliary valve 153 is in the fully open state, the first auxiliary throttling component 132 and the second auxiliary throttling component 134 are in the fully closed state, and the refrigerant is guided into the first gas-liquid separator 120 via the auxiliary pipeline 152.

[0295] In some embodiments, after the start-up phase of the cooling mode and the heating mode ends, the controller 50 drives the auxiliary throttling components to exit the fully closed state. That is, the controller 50 drives the first auxiliary throttling component 132 and the second auxiliary throttling component 134 to exit the fully closed state. The first auxiliary throttling component 132 and the second auxiliary throttling component 134 after exiting the fully closed state can be controlled according to the control algorithm used in the related art, which will not be described here.

[0296] In some embodiments, in the cooling mode, and when the compressor discharge pressure is less than or equal to the set pressure, the first auxiliary throttling component 132 and the second auxiliary throttling component 134 are driven to exit the fully closed state. For example, when a comparator circuit is used to compare the compressor discharge pressure and the set pressure, then when the compressor discharge pressure is less than or equal to the set pressure, the comparator circuit stops outputting a valid level signal, and the first auxiliary throttling component 132 and the second auxiliary throttling component 134 are driven to exit the fully closed state.

[0297] After the first auxiliary throttling component 132 and the second auxiliary throttling component 134 exit the fully closed state, the liquid mixture will flow more smoothly through the liquid communication pipe 171, and the liquid level balance between the first gas-liquid separator 120 and the second gas-liquid separator 121 will gradually be reached.

[0298] In some embodiments, the auxiliary valve 153 is in the fully open state, the first auxiliary throttling component 132 and the second auxiliary throttling component 134 are in the fully closed state, the first oil return adjusting component 141 and the second oil return adjusting component 137 are in the open valve state, the refrigerant is guided into the first gas-liquid separator 120 via the auxiliary pipeline 152, and the refrigerant between the first one-way valve 173 and the second one-way valve 174 is unloaded to the second gas-liquid separator 121 through the first oil return adjusting component 141 and the second oil return adjusting component 137.

[0299] It should be noted that any one of the technical solutions disclosed in the present disclosure can solve one or more of the above technical problems and achieve certain disclosed purposes; multiple technical disclosures can also be combined into one overall scheme to solve one or more of the above technical problems and achieve certain disclosed purposes; or some technical disclosures can be combined into one overall scheme, while related technologies and degraded schemes are used, but the degraded trend can be compensated for by the disclosed technical means, which can solve one or more of the above technical problems and achieve certain disclosed purposes to a certain extent. Each technical disclosure is combined into a complete technical scheme, which constitutes an organic and indivisible overall scheme, solves technical problems and achieves certain disclosed purposes.

[0300] Any one of the technical solutions disclosed in the present disclosure, and the recombination of multiple technical disclosures can form a complete technical scheme, and can solve one or more of the above technical problems to achieve the disclosed purposes, which belongs to the content of the present disclosure and is directly and without doubt determined according to the content of the present disclosure.

[0301] Those skilled in the art will understand that the scope of the disclosure of the present disclosure is not limited to the above specific embodiments, and certain elements of the embodiments can be modified and replaced without departing from the spirit of the present application. The scope of the present application is limited by the appended claims.

Claims

1. An air conditioning system, comprising: an indoor unit; and at least one outdoor unit, the indoor unit and the outdoor unit being connected to form a refrigerant circuit; any one of the at least one outdoor unit comprising: a plurality of compressors configured to compress refrigerant so that low-pressure refrigerant is compressed to form high-pressure refrigerant; a switching valve configured to switch the flow direction of refrigerant in the refrigerant circuit; a first gas-liquid separator, the first gas-liquid separator comprising: a first container; a plurality of liquid branches corresponding to the plurality of compressors, any one of the plurality of liquid branches being led out from the bottom of the first container and connected to one of the plurality of compressors; and an auxiliary throttling component corresponding to the plurality of liquid branches, the auxiliary throttling component being provided on any one of the liquid branches; a second gas-liquid separator, the second gas-liquid separator comprising: a second container; and a plurality of outlet pipelines, any one of the plurality of outlet pipelines being led out from the bottom of the second container and connected to one of the plurality of compressors; and a gas communication pipe, the top of the first gas-liquid separator and the top of the second gas-liquid separator being connected by the gas communication pipe; wherein the outdoor unit further comprises a controller configured to: in a case where any one of the plurality of compressors satisfies: the discharge superheat of the compressor is greater than a reference discharge superheat, and the operating frequency of the compressor is located in any one of a plurality of frequency band conditions corresponding to a plurality of transition operating states of the air conditioning system, drive the auxiliary throttling component to perform a corresponding action according to a first preset operating parameter of the auxiliary throttling component corresponding to the frequency band condition; wherein the reference discharge superheat serves as a reference value for identifying whether the discharge superheat of the compressor is too high.

2. The air conditioning system of claim 1, wherein, the first preset operating parameter comprises an adjustment ratio of the auxiliary throttling component and an adjustment period of the auxiliary throttling component, and the controller is further configured to: drive the auxiliary throttling component to be in an open valve state; determine a current opening degree of the auxiliary throttling component according to the product of the maximum opening degree of the auxiliary throttling component and the adjustment ratio; drive the auxiliary throttling component to open to the current opening degree; drive the auxiliary throttling component to return to a closed valve state after the adjustment period of the corresponding auxiliary throttling component ends; wherein the adjustment ratio is generated according to the discharge superheat of the compressor.

3. The air conditioning system of claim 2, wherein: the plurality of frequency band conditions are sequentially divided according to the operating frequency threshold of the compressor under different transition operating states; the higher the operating frequency threshold of the compressor, the shorter the adjustment period of the auxiliary throttling component corresponding to the frequency band condition.

4. The air conditioning system according to claim 2 or 3, wherein a polynomial fitting curve between the adjustment ratio and the discharge superheat of the compressor is stored in the controller; The controller is further configured to determine an adjustment ratio corresponding to the discharge superheat of the compressor according to the polynomial fitting curve and the discharge superheat of the compressor, and to generate the current opening degree of the auxiliary throttling component according to the product of the maximum opening degree of the auxiliary throttling component and the adjustment ratio.

5. The air conditioning system of any one of claims 1 to 4, wherein, The outdoor unit further comprises: a plurality of oil separators, which are arranged correspondingly to the plurality of compressors, and are respectively connected to the discharge ends of the plurality of compressors; a plurality of oil return branches, which are arranged correspondingly to the oil separators, and have two ends respectively connected to one oil separator and one liquid branch; an oil return adjusting component arranged on any one of the plurality of oil return branches; the refrigerant in the plurality of oil return branches, the plurality of liquid branches and the plurality of outlet pipelines converges into the compressor; The controller is further configured to: when the operating frequency of the compressor is in any one of the plurality of frequency bands corresponding to the plurality of transition operating states drive the oil return adjusting component to perform a corresponding action according to a second preset operating parameter of the oil return adjusting component corresponding to the frequency band condition.

6. The air conditioning system of claim 5, wherein, The second preset operating parameter includes an adjustment period of the oil return adjusting component, and the controller is further configured to: drive the oil return adjusting component to be in an open valve state; maintain the oil return adjusting component in the open valve state, and then drive the oil return adjusting component to return to a closed valve state after the adjustment period of the corresponding oil return adjusting component ends.

7. The air conditioning system of claim 5 or 6, wherein the plurality of frequency band conditions are sequentially divided according to the operating frequency thresholds of the compressor in different transition operating states; the higher the operating frequency threshold of the compressor, the longer the adjustment period of the oil return adjusting component corresponding to the frequency band condition.

8. The air conditioning system of any one of claims 1 to 7, wherein, The indoor unit comprises an indoor heat exchanger configured to exchange heat with indoor air; and the any one outdoor unit further comprises an outdoor heat exchanger configured to exchange heat with outdoor air; The air conditioning system has a cooling mode and a heating mode, in the cooling mode, the indoor heat exchanger serves as an evaporator, and the outdoor heat exchanger serves as a condenser; in the heating mode, the indoor heat exchanger serves as a condenser, and the outdoor heat exchanger serves as an evaporator; The first gas-liquid separator further comprises an inlet pipeline, a first end of the inlet pipeline is connected to the switching valve, and a second end of the inlet pipeline is located in the first container; the inlet pipeline is configured to introduce refrigerant flowing out of the evaporator into the first container.

9. The air conditioning system of any one of claims 1 to 8, wherein, The any one outlet pipeline comprises: a drainage pipe, which is arranged in the second container and is a straight pipe in the second container; and a communication pipe section, which is arranged outside the second container; a first end of the communication pipe section communicates with the drainage pipe, and a second end of the communication pipe section communicates with one compressor.

10. The air conditioning system of any one of claims 1 to 9, wherein, The at least one outdoor unit includes a plurality of outdoor units in communication with the indoor unit to form a refrigerant circuit; The controller is further configured to: In a case where the discharge superheat of the compressor of any one of the plurality of outdoor units is greater than the oil equalization discharge superheat, and the operating frequency of the compressor satisfies a preset load frequency condition, driving the auxiliary throttling component to perform a corresponding action according to a third preset operating parameter of the auxiliary throttling component corresponding to the preset load frequency condition; The oil equalization discharge superheat serves as a reference value for identifying whether the air conditioning system is relatively over-capacitated in refrigeration or heating.

11. The air conditioning system of claim 10, wherein, The third preset operating parameter includes an adjustment ratio and an adjustment period; the controller is further configured to: drive the auxiliary throttling component to be in an open valve state; generate a current opening degree of the auxiliary throttling component according to the product of the maximum opening degree of the auxiliary throttling component and the adjustment ratio; drive the auxiliary throttling component to open to the current opening degree; drive the auxiliary throttling component to return to a closed valve state after the adjustment period of the corresponding auxiliary throttling component ends; The adjustment ratio is generated according to the discharge superheat of the compressor.

12. An air conditioning system, comprising: a plurality of indoor units; an outdoor unit connected to the plurality of indoor units; and a liquid pipe connecting the outdoor unit and the plurality of indoor units; The outdoor unit includes: a compressor configured to compress refrigerant to form high-pressure refrigerant from low-pressure refrigerant; an outdoor heat exchanger configured to exchange heat between outdoor air and refrigerant transmitted in the outdoor heat exchanger; an over-cooler arranged between the outdoor heat exchanger and the plurality of indoor units, the over-cooler being configured to separate a portion of high-temperature high-pressure liquid refrigerant in the liquid pipe; the over-cooler includes: an auxiliary pipeline, a first end of the auxiliary pipeline being connected to the outdoor heat exchanger; and an auxiliary valve arranged in the auxiliary pipeline; a first gas-liquid separator, a second end of the auxiliary pipeline being connected to the first gas-liquid separator and connected to the suction side of the compressor through the first gas-liquid separator; and a second gas-liquid separator connected to the suction side of the compressor; The auxiliary valve is in a fully open state, and the refrigerant is guided into the first gas-liquid separator through the auxiliary pipeline. The outdoor unit further includes:

13. The air conditioning system of claim 12, wherein, a liquid communication pipe, a first end of the liquid communication pipe being connected to the bottom of the first gas-liquid separator, and a second end of the liquid communication pipe being connected to the bottom of the second gas-liquid separator; and a circuit valve arranged in the liquid communication pipe; The auxiliary valve is in a fully open state, and the circuit valve is in a fully closed state, and the refrigerant is guided into the first gas-liquid separator through the auxiliary pipeline. The outdoor unit further includes:

14. The air conditioning system of claim 13, wherein, a gas communication pipe, a first end of the gas communication pipe being connected to the top of the first gas-liquid separator, and a second end of the gas communication pipe being connected to the top of the second gas-liquid separator. ​ 15. The air conditioning system of any one of claims 12 to 14, wherein, The second gas-liquid separator further comprises an outlet pipeline, a first end of the outlet pipeline being communicated with the second gas-liquid separator, and a second end of the outlet pipeline being communicated with the suction side of the compressor.

16. The air conditioning system of claim 15, wherein, The outlet pipeline comprises a drainage pipe, the drainage pipe being arranged in the second gas-liquid separator, and the drainage pipe being arranged in a bent manner in the second gas-liquid separator.

17. The air conditioning system of any one of claims 12 to 16, wherein, The subcooler further comprises a main pipeline, the main pipeline and the auxiliary pipeline being arranged in parallel and adjacent to each other; A first end of the main pipeline is connected to the liquid side pipe of the outdoor heat exchanger, and a second end of the main pipeline is connected to the liquid pipe; The first end of the auxiliary pipeline is connected to the liquid side pipe of the outdoor heat exchanger, and the second end of the auxiliary pipeline is connected to the first gas-liquid separator and communicated with the suction side of the compressor through the first gas-liquid separator.

18. The air conditioning system of claim 17, wherein, The outdoor unit comprises: a first compressor; a second compressor; a first oil separator arranged at an exhaust end of the first compressor; a second oil separator arranged at an exhaust end of the second compressor; a first pressure reducer connected between the first compressor and the first oil separator; and a second pressure reducer connected between the second compressor and the second oil separator; The second gas-liquid separator comprises: a first outlet pipeline, a first end of the first outlet pipeline being communicated with the second gas-liquid separator, and a second end of the first outlet pipeline being communicated with the suction side of the first compressor; the first outlet pipeline comprises a first drainage pipe, the first drainage pipe being arranged in the second gas-liquid separator; a second outlet pipeline, a first end of the second outlet pipeline being arranged in the second gas-liquid separator, and a second end of the second outlet pipeline being communicated with the suction side of the second compressor; the second outlet pipeline comprises a second drainage pipe, the second drainage pipe being arranged in the second gas-liquid separator.

19. The air conditioning system of claim 18, wherein, The first outlet pipeline and the second outlet pipeline have the same pipe length in the second gas-liquid separator.

20. The air conditioning system of claim 18 or 19, wherein, At least one oil return hole is arranged on the first outlet pipeline and the second outlet pipeline.

21. The air conditioning system of any of claims 12 to 20, wherein, The first gas-liquid separator further comprises a liquid branch, the first gas-liquid separator being connected to the compressor through the liquid branch; the second gas-liquid separator is connected to the suction side of the compressor and the first gas-liquid separator, respectively; The auxiliary valve is in a fully open state, and the refrigerant is guided into the first gas-liquid separator through the auxiliary pipeline.

22. The air conditioning system of claim 21, wherein, The second gas-liquid separator further comprises an outlet pipeline, a first end of the outlet pipeline being communicated with the second gas-liquid separator, and a second end of the outlet pipeline being communicated with the suction side of the compressor; The liquid branch is connected to the first gas-liquid separator and the outlet pipeline; the first gas-liquid separator further comprises an auxiliary throttling component, the auxiliary throttling component being arranged in the liquid branch; The auxiliary valve is in a fully open state, and the auxiliary throttling component is in a fully closed state, and the refrigerant is guided into the first gas-liquid separator through the auxiliary pipeline.

23. The air conditioning system of claim 22, wherein, The outdoor unit further comprises: an oil separator, the oil separator being connected to an exhaust end of the compressor; An oil return branch connecting the oil separator and the outlet pipeline; and An oil return regulating component arranged between the oil separator and the outlet pipeline; Wherein, the auxiliary valve is in a fully open state, the auxiliary throttling component is in a fully closed state, the oil return regulating component is in an open valve state, and the refrigerant is guided into the first gas-liquid separator via the auxiliary pipeline.

24. The air conditioning system of claim 23, wherein, The outdoor unit comprises: A first compressor, A second compressor; A first outlet pipeline, a first end of the first outlet pipeline being communicated with the second gas-liquid separator, and a second end of the first outlet pipeline being communicated with a suction side of the first compressor; the first outlet pipeline comprises a first flow guide pipe arranged in the second gas-liquid separator; A second outlet pipeline, a first end of the second outlet pipeline being arranged in the second gas-liquid separator, and a second end of the second outlet pipeline being communicated with a suction side of the second compressor; the second outlet pipeline comprises a second flow guide pipe arranged in the second gas-liquid separator; A first liquid branch connecting the first gas-liquid separator and the first outlet pipeline, and a first auxiliary throttling component being arranged on the first liquid branch; and A second liquid branch connecting the second gas-liquid separator and the second outlet pipeline, and a second auxiliary throttling component being arranged on the second liquid branch; Wherein, the auxiliary valve is in a fully open state, the first auxiliary throttling component and the second auxiliary throttling component are in a fully closed state, and the refrigerant is guided into the first gas-liquid separator via the auxiliary pipeline.

25. The air conditioning system of claim 24, wherein, The outdoor unit comprises: A first oil separator connecting a first compressor and the first outlet pipeline; A first oil return regulating component arranged between the first oil separator and the first outlet pipeline; A second oil separator connecting a second compressor and the second outlet pipeline; and A second oil return regulating component arranged between the second oil separator and the second outlet pipeline; Wherein, the auxiliary valve is in a fully open state, the first auxiliary throttling component and the second auxiliary throttling component are in a fully closed state, the first oil return regulating component and the second oil return regulating component are in an open valve state, a part of the refrigerant is guided into the first gas-liquid separator via the auxiliary pipeline, and another part of the refrigerant is guided into the second gas-liquid separator via the first oil return regulating component and the second oil return regulating component.

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