AIR CONDITIONING SYSTEM, AND METHOD FOR CONTROLLING AIR CONDITIONING SYSTEM

Abstract

An air conditioning system includes an indoor electronic expansion valve, and at least one liquid phase branch pipe. Each liquid phase branch pipe includes a first flow pipe and a second flow pipe. An end of the second flow pipe is communicated to an end of the first flow pipe, and another end of the second flow pipe is communicated to the indoor electronic expansion valve. The liquid phase branch pipe is configured to branch or converge a refrigerant flowing through the liquid phase branch pipe. The first flow pipe includes at least one mixing member, each mixing member has a plurality of first through holes, and the plurality of first through holes are used to communicate two ends of the first flow pipe.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of International Application No. PCT/CN2022/133299, filed on Nov. 21, 2022, which claims priority to Chinese Patent Application No. 202210439309.5, filed on Apr. 25, 2022, and Chinese Patent Application No. 202210609487.8, filed on May 31, 2022, which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to the technical field of air conditioners and, in particular, to an air conditioning system and a method for controlling an air conditioning system.

BACKGROUND

With an improvement of people's living standards, more and more places have installed air conditioning systems to bring people a better life experience. An amount of refrigerant in an air conditioning system affects performance of the air conditioning system. In general, a charging amount of refrigerant in the air conditioning system is mostly obtained through experience of an installer or precise calculations. Therefore, the charging amount of refrigerant may be inaccurate, thereby leading to a decrease in performance of the air conditioning system.

SUMMARY

In an aspect, an air conditioning system is provided. The air conditioning system includes an outdoor unit, an indoor unit, and at least one liquid phase branch pipe. The outdoor unit includes a compressor, an outdoor electronic expansion valve, and an outdoor heat exchanger. The indoor unit includes an indoor electronic expansion valve and an indoor heat exchanger. The compressor compresses a refrigerant and discharges the compressed refrigerant, and the outdoor heat exchanger condenses the compressed refrigerant; the outdoor electronic expansion valve and the indoor electronic expansion valve adjust an amount of the refrigerant condensed by the outdoor heat exchanger; and the indoor heat exchanger evaporates the refrigerant adjusted by the indoor electronic expansion valve. Each liquid phase branch pipe includes a first flow pipe and a second flow pipe. An end of the second flow pipe is communicated to an end of the first flow pipe, and another end of the second flow pipe is communicated to the indoor electronic expansion valve. The liquid phase branch pipe is configured to branch or converge a refrigerant flowing through the liquid phase branch pipe. The first flow pipe includes at least one mixing member, each mixing member has a plurality of first through holes, and the plurality of first through holes are used to communicate two ends of the first flow pipe.

In another aspect, a method for controlling an air conditioning system is provided. The air conditioning system includes an outdoor unit, an indoor unit, and a controller. The outdoor unit includes a compressor, an outdoor electronic expansion valve, and an outdoor heat exchanger. The indoor unit includes an indoor electronic expansion valve and an indoor heat exchanger. The compressor compresses a refrigerant and discharges the compressed refrigerant, and the outdoor heat exchanger condenses the compressed refrigerant; the outdoor electronic expansion valve and the indoor electronic expansion valve adjust amount of the refrigerant condensed by the outdoor heat exchanger; and the indoor heat exchanger evaporates the refrigerant adjusted by the indoor electronic expansion valve. The method for controlling the air conditioning system includes: obtaining an opening degree of the indoor electronic expansion valve; in a case where a first preset condition is satisfied, adjusting an opening degree of the outdoor electronic expansion valve according to a relationship between a subcooling degree of the outdoor heat exchanger and a first target subcooling degree interval, and adjusting the opening degree of the indoor electronic expansion valve according to a relationship between an exhaust superheat degree of the compressor and a target exhaust superheat degree interval; and in a case where the first preset condition is not satisfied, adjusting the opening degree of the outdoor electronic expansion valve and the opening degree of the indoor electronic expansion valve according to a relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval. The first preset condition includes that the opening degree of the indoor electronic expansion valve is less than a first preset opening degree.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the technical solutions of the embodiments of the present disclosure more clearly, accompanying drawings to be used in some embodiments of the present disclosure will be introduced briefly below. However, the accompanying drawings to be described below are merely some embodiments of the present disclosure, and a person of ordinary skill in the art may obtain other drawings according to these drawings. In addition, the accompanying drawings in the following description may be regarded as schematic diagrams and are not limitations on actual sizes of products, actual processes of methods, and actual timings of signals to which the embodiments of the present disclosure relate.

FIG. 1 is a structural diagram of an air conditioning system, in accordance with some embodiments of the present disclosure;

FIG. 2 is a schematic diagram of a controller, in accordance with some embodiments of the present disclosure;

FIG. 3 is a schematic diagram of an air conditioning system, in accordance with some embodiments of the present disclosure;

FIG. 4A is a schematic diagram of another air conditioning system, in accordance with some embodiments of the present disclosure;

FIG. 4B is a pressure enthalpy diagram, in accordance with some embodiments of the present disclosure;

FIG. 5 is a flow diagram of a controlling mode, in accordance with some embodiments of the present disclosure;

FIG. 6 is a flow diagram of another controlling mode, in accordance with some embodiments of the present disclosure;

FIG. 7 is a flow diagram of a method for controlling an air conditioning system, in accordance with some embodiments;

FIG. 8 is a flow diagram of yet another controlling mode, in accordance with some embodiments of the present disclosure;

FIG. 9 is a flow diagram of yet another controlling mode, in accordance with some embodiments of the present disclosure;

FIG. 10 is a flow diagram of another method for controlling an air conditioning system, in accordance with some embodiments of the present disclosure;

FIG. 11 is a structural diagram of another air conditioning system, in accordance with some embodiments of the present disclosure;

FIG. 12A is a structural diagram of a liquid phase branch pipe, in accordance with some embodiments of the present disclosure;

FIG. 12B is a structural diagram of another liquid phase branch pipe, in accordance with some embodiments of the present disclosure;

FIG. 13 is a structural diagram of yet another liquid phase branch pipe, in accordance with some embodiments of the present disclosure;

FIG. 14 is a structural diagram of a first flow pipe, in accordance with some embodiments of the present disclosure;

FIG. 15 is a structural diagram of the first flow pipe shown in FIG. 14 taken along the line A-A;

FIG. 16 is a partial enlarged view of part D in FIG. 15;

FIG. 17 is another partial enlarged view of part D in FIG. 15;

FIG. 18 is yet another partial enlarged view of part D in FIG. 15;

FIG. 19 is a structural diagram of the first flow pipe shown in FIG. 14 taken along the line B-B;

FIG. 20 is a structural diagram of a first orifice plate mixing piece, in accordance with some embodiments of the present disclosure;

FIG. 21 is a structural diagram of the first flow pipe shown in FIG. 14 taken along the line C-C;

FIG. 22 is a structural diagram of a second orifice plate mixing piece, in accordance with some embodiments of the present disclosure;

FIG. 23 is a structural diagram of another second orifice plate mixing piece, in accordance with some embodiments of the present disclosure;

FIG. 24 is a structural diagram of yet another second orifice plate mixing piece, in accordance with some embodiments of the present disclosure;

FIG. 25 is a schematic diagram of a plurality of mixing members in a first flow pipe, in accordance with some embodiments of the present disclosure; and

FIG. 26 is a flow diagram of yet another control method of an air conditioning system, in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION

The technical solutions in some embodiments of the present disclosure will be described clearly and completely with reference to the accompanying drawings. However, the described embodiments are merely some, but not all, embodiments of the present disclosure. All other embodiments obtained on a basis of the embodiments of the present disclosure by a person of ordinary skill in the art shall be included in the protection scope of the present disclosure.

Unless the context requires otherwise, throughout the specification and claims, the term “comprise” and other forms thereof such as the third-person singular form “comprises” and the present participle form “comprising” are construed as an open and inclusive meaning, i.e., “including, but not limited to.” In the description of the specification, the terms such as “one embodiment,” “some embodiments,” “exemplary embodiments,” “example,” “specific example,” or “some examples” are intended to indicate that specific features, structures, materials, or characteristics related to the embodiment(s) or example(s) are included in at least one embodiment or example of the present disclosure. Schematic representations of the above terms do not necessarily refer to the same embodiment(s) or example(s). In addition, the specific features, structures, materials, or characteristics may be included in any one or more embodiments or examples in any suitable manner.

Hereinafter, the terms such as “first” and “second” are only used for descriptive purposes and cannot be construed as indicating or implying the relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with “first” and “second” may explicitly or implicitly include one or more of these features. In the description of the embodiments of the present disclosure, the term “a plurality of” means two or more unless otherwise specified.

In the description of the embodiments, the expressions “coupled” and “connected” and derivatives thereof may be used. The term “connected” should be understood in a broad sense. For example, “connected” may represent a fixed connection, a detachable connection, or connected as an integral body; and “connected” may be directly “connected” or indirectly “connected” through an intermediate means. The term “coupled” may be used in the description of some embodiments to indicate that two or more components are in direct physical or electrical contact with each other. The term “coupled” or “communicatively coupled,” however, may also mean that two or more components are not in direct contact with each other but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the content herein.

The phrase “At least one of A, B, and C” has the same meaning as the phrase “at least one of A, B, or C”, and both include the following combinations of A, B, and C: only A, only B, only C, a combination of A and B, a combination of A and C, a combination of B and C, and a combination of A, B, and C.

The phrase “A and/or B” includes the following three combinations: only A, only B, and a combination of A and B.

As used herein, depending on the context, the term “if” is optionally construed as “when” or “in a case where” or “in response to determining” or “in response to detecting.” Similarly, depending on the context, the phrase “if it is determined” or “if [a stated condition or event] is detected” is optionally construed as “in a case where it is determined,” “in response to determining,” “in a case where [the stated condition or event] is detected,” or “in response to detecting [the stated condition or event].”

The phase “applicable to” or “configured to” used herein means an open and inclusive language, which does not exclude apparatuses that are applicable to or configured to perform additional tasks or steps.

In addition, the use of the phrase “based on” is meant to be open and inclusive, since a process, step, calculation, or other action that is “based on” one or more of the stated conditions or values may, in practice, be based on additional conditions or values exceeding those stated.

Refrigerant is a substance that may turn into a gas by absorbing heat and turn into a liquid by releasing heat. In an air conditioning system, the refrigerant transfers energy through evaporation or condensation in an indoor heat exchanger and an outdoor heat exchanger respectively, so as to produce cooling or heating effects. The amount of the refrigerant contained in the air conditioning system is critical to the performance and reliability of the air conditioning system.

The amount of the refrigerant in the air conditioning system is critical to system performance and reliability. In a case where the amount of refrigerant is relatively too much, the amount of refrigerant remaining in the condenser will be large, the pressure will be high, the energy efficiency of the system will be low, and the system may have reliability problems. In a case where the amount of refrigerant is relatively too small, the amount of refrigerant remaining in the condenser will be insufficient, the subcooling degree of the refrigerant will be small, and the dryness of the refrigerant entering the evaporator will be large, thereby resulting in reduced capacity.

FIG. 1 is a structural diagram of an air conditioning system, in accordance with some embodiments of the present disclosure. As shown in FIG. 1, the air conditioning system 1 includes an outdoor unit 10 and an indoor unit 20. For example, in some embodiments of the present disclosure, the air conditioning system 1 may include a plurality of indoor units 20, such as two indoor units 20 in FIG. 1.

Referring to FIG. 1, in the air conditioning system 1, the outdoor unit 10 includes a gas-liquid separator 101, a compressor 102, an outdoor heat exchanger 103, an outdoor electronic expansion valve 104, a liquid side stop valve 105, a gas side stop valve 110, and a four-way valve 111. The indoor unit 20 includes indoor electronic expansion valves 107 (including a first indoor electronic expansion valve 1071 and a second indoor electronic expansion valve 1072) and indoor heat exchangers 108 (including a first indoor heat exchanger 1081 and a second indoor heat exchanger 1082). A first indoor unit 21 includes the first indoor electronic expansion valve 1071 and the first indoor heat exchanger 1081, and a second indoor unit 22 includes the second indoor electronic expansion valve 1072 and the second indoor heat exchanger 1082.

In some embodiments, the outdoor unit 10 and the indoor unit 20 may be communicated through a unit connecting liquid pipe 106 and a unit connecting air pipe 109.

For example, opening degrees of the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 will affect the flow speed of the refrigerant in the air conditioning system 1. For example, in a case where the opening degrees of the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 are changed, the flow rate of the refrigerant in the air conditioning system 1 is also changed.

In some embodiments, the outdoor unit 10 further includes an outdoor fan and/or outdoor fan motor. The outdoor fan motor is used to drive or change the rotational speed of the outdoor fan.

In some embodiments, the indoor unit 20 further includes one or more of the following: a display, an indoor fan, and an indoor fan motor. The display is used to display the indoor temperature or the operating mode. The indoor fan motor is used to drive or change the rotational speed of the indoor fan.

In some embodiments, the air conditioning system 1 further includes a controller. As shown in FIG. 2, the controller 30 includes an outdoor controller 31 and an indoor controller 32. The indoor controller 32 may be coupled to the outdoor controller 31 through a manner of wired or wireless communication. The outdoor controller 31 may be installed in the outdoor unit 10 or may be installed independently outside the outdoor unit 10. The outdoor controller 31 is used to control components in the outdoor unit 10 to perform relevant operations. The indoor controller 32 may be installed in the indoor unit 20 or may be installed independently outside the indoor unit 20 and is used to control components in the indoor unit 20 to perform relevant operations.

For example, the controller 30 may be a central processing unit (CPU), a network processor (NP), a digital signal processing (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The controller 30 may further be other devices with processing functions, such as a circuit, a device, or a software module. The controller 30 may be used to control the operation of each component in the air conditioning system 1, so that each component in the air conditioning system 1 operates to achieve each predetermined function.

In some embodiments, as shown in FIG. 2, the outdoor controller 31 may include a first memory 311, and the indoor controller 32 may include a second memory 321. The first memory 311 and the second memory 321 may include a high-speed random access memory respectively or may further include a non-volatile memory, such as a magnetic disk storage device, a flash memory device, or other volatile solid state storage devices. It will be noted that the division of components in some embodiments of the present disclosure is only functional division. For example, the outdoor controller 31 and the indoor controller 32 may also be integrated into a controller; and the first memory 311 and the second memory 321 may also be integrated into a memory. The present disclosure does not limit this.

For example, the first memory 311 is used to store application programs and data related to the outdoor unit 10, such as opening degree information of the outdoor electronic expansion valve 104. The outdoor controller 31 executes various functions and data processing of the air conditioning system 1 by running the application program and data stored in the first memory 311. The second memory 321 is used to store application programs and data related to the indoor unit 20, such as opening degree information of the indoor electronic expansion valve 107. The indoor controller 32 executes various functions and data processing of the air conditioning system 1 by running the application programs and data stored in the second memory 321.

In some embodiments, there is a communication connection between the outdoor controller 31 and the outdoor unit 10 for controlling the outdoor unit 10 to perform relevant operations according to relevant instructions. For example, the outdoor controller 31 may control the opening degree of the outdoor electronic expansion valve 104 according to the exhaust superheat degree of the compressor 102. The outdoor controller 31 may further obtain the outdoor ambient temperature, store the obtained outdoor ambient temperature in the first memory 311, and adjust the opening degree of the outdoor electronic expansion valve 104 according to the outdoor ambient temperature. The outdoor controller 31 may further control the rotation of the four-way valve 111 according to relevant instructions, so as to control the air conditioning system 1 to perform cooling or heating.

In some embodiments, the indoor controller 32 is communicatively connected to the indoor unit 20 and is used to control the indoor unit 20 to perform relevant operations according to relevant instructions. For example, the indoor controller 32 may control the opening degree of the indoor electronic expansion valve 107 according to the exhaust superheat degree of the compressor 102. Or, the indoor controller 32 may further obtain the indoor ambient temperature according to relevant instructions.

FIG. 3 is a schematic diagram of an air conditioning system, in accordance with some embodiments of the present disclosure. In some embodiments, as shown in FIG. 3, the air conditioning system 1 may further include a first temperature sensor 113, a compressor exhaust pressure sensor 114, a compressor exhaust temperature sensor 115, a second temperature sensor 116, a third temperature sensor 117, and a communicator 118 that are coupled to the controller 30.

For example, a position distribution of the first temperature sensor 113, the compressor exhaust pressure sensor 114, the compressor exhaust temperature sensor 115, the second temperature sensor 116, and the third temperature sensor 117 is as shown in FIG. 4A. As shown in FIG. 4A, an end of the first temperature sensor 113 is connected to the outdoor electronic expansion valve 104 and another end of the first temperature sensor 113 is connected to the outdoor heat exchanger 103. The first temperature sensor 113 is used to detect a temperature of a refrigerant at an outlet of the outdoor heat exchanger 103. The compressor exhaust pressure sensor 114 may be located at an exhaust port of the compressor 102 and used to detect a pressure of a gaseous refrigerant discharged from the compressor 102. The compressor exhaust temperature sensor 115 may also be set at the exhaust port of the compressor 102 and used to detect a temperature of the gaseous refrigerant discharged from the compressor 102. An end of the second temperature sensor 116 is connected to the indoor electronic expansion valve 107, and another end of the second temperature sensor 116 is connected to the indoor heat exchanger 108. The second temperature sensor 116 is used to detect a temperature of a refrigerant at an outlet of the indoor heat exchanger 108. An end of the third temperature sensor 117 is connected to the indoor heat exchanger 108, and another end of the third temperature sensor 117 is connected to the unit connecting air pipe 109. The third temperature sensor 117 is used to detect a temperature of a refrigerant at another outlet of the indoor unit heat exchanger.

In some embodiments, the communicator 118 is used to establish a communication connection with other network entities. For example, the communicator 118 may establish a communication connection with a terminal device. The air conditioning system 1 may receive control instructions sent by the terminal device through the communicator 118 and execute corresponding processing according the control instructions, so as to implement the interaction between the user and the air conditioning system 1. For example, the communicator 118 may include a radio frequency (RF) component, a cellular component, a wireless fidelity (WIFI) component, and a GPS component. For example, the RF component may be used to send received information to the controller 30 for processing and send signals generated by the controller 30. For example, the RF component may include, but is not limited to, an antenna, at least one amplifier, a transceiver, a coupler, a low noise amplifier (LNA), or a duplexer.

In some embodiments, the air conditioning system 1 may further include a remote control, which may communicate to the controller 30 using infrared rays or other communication methods. The user may perform various control operations on the air conditioning system 1 through the remote control, so as to implement the interaction between the user and the air conditioning system 1.

For example, the amount of refrigerant of the air conditioning system 1 includes the original amount of refrigerant in the air conditioning system 1 (such as the refrigerant charging amount of the outdoor unit 10) and the additional amount of refrigerant. The additional amount of refrigerant needs to be determined according to the unit connecting piping between the outdoor unit 10 and the indoor unit 20. For example, a length of the unit connecting liquid pipe 106 shown in FIG. 1 is related to the installation environment of the outdoor unit 10 and the indoor unit 20. Different lengths of the pipe require different additional amounts of refrigerant. Therefore, when installing the air conditioning system 1, the installer needs to calculate the additional amount of refrigerant according to information such as the unit connecting piping length, the pipe diameter, and the additional refrigerant calculation method. If the additional amount of refrigerant is inaccurate, the performance of the air conditioning system 1 will decrease.

In the related technology, the refrigerant free addition in the air conditioning system 1 may be implemented by adding components such as a liquid reservoir in the air conditioning system 1. However, it is still necessary to provide sufficient refrigerant (i.e., the original amount of refrigerant plus the additional amount of refrigerant) to ensure the normal operation of the air conditioning system 1, which has problems of complex structure and high cost of the air conditioning system 1.

The air conditioning system 1 provided by some embodiments of the present disclosure may implement the refrigerant free addition, so that the air conditioning system 1 may still operate normally with the original amount of refrigerant. In this way, a problem of performance degradation of the air conditioning system 1 after installation caused by the inaccurate calculation of refrigerant by the installer may be avoided, the structure of the air conditioning system 1 may be simplified, the cost may be reduced, and the reliability of the air conditioning system 1 may be improved.

For example, in a case where the length of the unit connecting piping (such as a maximum charging-free unit connecting piping) is L0, the corresponding charging amount of refrigerant of the air conditioning system in the related art is M1, and the charging amount of refrigerant of the air conditioning system 1 provided by some embodiments of the present disclosure is M0. M1 is greater than M0 (i.e., M1>M0).

The following describes the working process of the air conditioning system 1 with reference to FIG. 4A, taking the cooling of the air conditioning system 1 as an example. For example, in a case where the air conditioning system 1 performs cooling, the outdoor heat exchanger 103 is used as a condenser, and the indoor heat exchanger 108 is used as an evaporator. A direction of an arrow in FIG. 4A is a flow direction of the refrigerant during cooling by the air conditioning system 1. The compressor 102 controls an evaporation temperature of the indoor unit 20. The compressor 102 sucks a low-pressure superheated refrigerant (a refrigerant state at point A in FIG. 4A) from the gas-liquid separator 101 and compresses it to a high-temperature and high-pressure refrigerant, which flows through the four-way valve 111 and is discharged to the outdoor heat exchanger 103 (a refrigerant state at point B in FIG. 4A). In the outdoor heat exchanger 103, the high-temperature and high-pressure refrigerant exchanges heat with the air to be cooled into a high-pressure supercooled liquid refrigerant (a refrigerant state at point C in FIG. 4A). The outdoor electronic expansion valve 104 is in a fully open state, and the high-pressure supercooled liquid refrigerant flows through the outdoor electronic expansion valve 104 and is enthalpy-throttled to point D. The refrigerant at point D flows through the unit connecting liquid pipe 106 and is enthalpy-throttled to reduce the pressure to point E. The indoor electronic expansion valve 107 controls the superheat degree of the indoor heat exchanger 108 and the exhaust superheat degree of the compressor 102 to throttle the high-pressure liquid refrigerant to a low-pressure gas-liquid two-phase state (a refrigerant state at point F in FIG. 4A). After the refrigerant at point F enters the indoor heat exchanger 108, it may be evaporated into a low-pressure superheated gas state (a refrigerant state at point G in FIG. 4A).

FIG. 4B is a pressure enthalpy diagram, in accordance with some embodiments of the present disclosure. For example, a pressure enthalpy diagram in a case where the air conditioning system 1 operates in the cooling mode. A-B′-C′-D′-E′-F′ may be used to represent a pressure enthalpy diagram of the operation of the air conditioning system in the related art in a case where the amount of refrigerant is M0. A-B-C-D-E-F is a pressure enthalpy diagram of the operation of the air conditioning system in a case where the amount of refrigerant is M0. Referring to FIG. 4B, in a case where the air conditioning system in the related art operates with a refrigerant amount of M0, due to the insufficient refrigerant amount, the refrigerant at the outlet C′ of the condenser will be no subcooling degree, and the refrigerant at the outlet will be in the two-phase state. After flowing through fully opened outdoor electronic expansion valve 104, the pressure loss of the refrigerant is reduced to D′ state. After flowing through the unit connecting liquid pipe 106, the pressure loss of the refrigerant is reduced to E′ state. After flowing through the indoor electronic expansion valve 107, the refrigerant is throttled to F′ state. Due to lack of refrigerant, the refrigerant at the outlet of the condenser is no subcooling degree, resulting in high dryness at the inlet of the evaporator and lack of liquid refrigerant, which leads to a decrease in the evaporation capacity of the evaporator and a decrease in the refrigeration performance of the air conditioning system 1. Continuing to refer to FIG. 4B, in the air conditioning system 1, the subcooling degree of the refrigerant at point C at the outlet of the condenser is greater than that at point C′ at the outlet of the condenser, which ensures that the refrigerant flows through the outdoor electronic expansion valve 104 is in a medium-pressure two-phase state, the amount of refrigerant in the unit connecting liquid pipe 106 is decreased, and the amount of refrigerant at the outlet of condenser is increased. Therefore, the dryness of the refrigerant entering the evaporator is decreased, and the cooling capacity of the air conditioning system 1 is improved. A heating process of the air conditioning system 1 is similar, and details will not be repeated herein.

The controller 30 detects the subcooling degree of the refrigerant at the outlet of the outdoor heat exchanger 103. In a case where the subcooling degree of the refrigerant at the outlet of the outdoor heat exchanger 103 is less than a preset subcooling degree, the controller 30 may reduce the opening degree of the outdoor electronic expansion valve 104, so as to throttle the refrigerant flowing through the outdoor electronic expansion valve 104 to a gas-liquid two-phase refrigerant with medium or low pressure. That is, the refrigerant flowing through the unit connecting liquid pipe 106 is in a gas-liquid two-phase state, thereby reducing the remaining amount of refrigerant in the unit connecting liquid pipe 106, increasing the subcooling degree of refrigerant at the outlet of the outdoor heat exchanger 103, reducing the dryness of the indoor heat exchanger 108, and improving the cooling capacity of the indoor heat exchanger 108. For example, the amount of refrigerant that causes the subcooling degree of the outdoor heat exchanger 103 to be increased comes from the reduction of the refrigerant in the unit connecting liquid pipe 106.

In some embodiments, the compressor 102 compresses the refrigerant and discharges a compressed refrigerant, and the outdoor heat exchanger 103 condenses the compressed refrigerant. The outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 adjust the amount of refrigerant condensed by the outdoor heat exchanger 103 in sequence, and the indoor heat exchanger 108 evaporates the refrigerant adjusted by the indoor electronic expansion valve 107.

The controller 30 is configured to obtain the opening degree of the indoor electronic expansion valve 107, adjust the opening degree of the outdoor electronic expansion valve 104 according to a relationship between the subcooling degree of the outdoor heat exchanger 103 and a first target subcooling degree interval in a case where a first preset condition is satisfied, and adjust the opening degree of the indoor electronic expansion valve 107 according to a relationship between the exhaust superheat degree of the compressor 102 and a target exhaust superheat degree interval.

In some embodiments, the first preset condition includes that the opening degree of the indoor electronic expansion valve 107 is lesser than a first preset opening degree.

The outdoor heat exchanger 103 condenses the refrigerant. In this case, the air conditioning system 1 is in the cooling mode. In a case where the air conditioning system 1 operates in the cooling mode, the controller 30 obtains the opening degree of the indoor electronic expansion valve 107 and determines whether the opening degree of the outdoor electronic expansion valve 104 is less than the first preset opening degree.

For example, the opening degree of the indoor electronic expansion valve 107 being less than the first preset opening degree includes that the opening degrees of the indoor electronic expansion valves 107 (e.g., the first indoor electronic expansion valve 1071 and the second indoor electronic expansion valve 1072) of the indoor units 20 in an operating state in the air conditioning system 1 are all less than the first preset opening degree. In some embodiments, the first preset opening degree is less than a maximum opening degree of the indoor electronic expansion valve 107. For example, the first preset opening degree may be 90% of the maximum opening degree of the indoor electronic expansion valve 107.

The opening degrees of the indoor electronic expansion valves 107 are all less than the first preset opening degree, indicating that the indoor electronic expansion valves 107 have adjustable room. For example, the outdoor electronic expansion valve 104 may further be adjusted less. Correspondingly, the outdoor electronic expansion valve 104 further has corresponding adjustable room. In this case, the controller 30 may adjust the opening degree of the outdoor electronic expansion valve 104 according to the relationship between the subcooling degree of the outdoor heat exchanger 103 and the first target subcooling degree interval and adjust the opening degree of the indoor electronic expansion valve 107 according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval.

For example, the opening degree of the outdoor electronic expansion valve 104 may be referred to as EVO, the minimum opening degree of the outdoor electronic expansion valve 104 may be referred to as EVO_min, and the maximum opening degree of the outdoor electronic expansion valve 104 may be referred to as EVO_max. The opening degree of the indoor electronic expansion valve 107 may be referred to as EVI, the minimum opening degree of the indoor electronic expansion valve 107 may be referred to as EVI_min, and the maximum opening degree of the indoor electronic expansion valve 107 may be referred to as EVI_max.

In some embodiments, the controller 30 is configured to increase the opening degree of the outdoor electronic expansion valve 104 if the subcooling degree of the outdoor heat exchanger 103 is greater than an upper limit of the first target subcooling degree interval, reduce the opening degree of the outdoor electronic expansion valve 104 if the subcooling degree of the outdoor heat exchanger 103 is less than a lower limit of the first target subcooling degree interval, and control the opening degree of the outdoor electronic expansion valve 104 to remain unchanged if the subcooling degree of the outdoor heat exchanger 103 is greater than or equal to the lower limit of the first target subcooling degree interval and is less than or equal to the upper limit of the first target subcooling degree interval.

For example, the subcooling degree of the outdoor heat exchanger 103 may be referred to as ΔToSC, and the target subcooling degree of the outdoor heat exchanger 103 may be referred to as ΔToSCo. The subcooling degree ΔToSC of the outdoor heat exchanger 103 is equal to a difference between Tc and Te (i.e., ΔToSC=Tc−Te). Tc represents the saturation temperature corresponding to the pressure Pd detected by the compressor exhaust pressure sensor 114 and the compressor exhaust temperature sensor 115, and Te represents the temperature of the refrigerant at the outlet of the outdoor heat exchanger 103 detected by the first temperature sensor 113.

The target subcooling degree ΔToSCo of the outdoor heat exchanger 103 may be different due to different conditions of ambient temperatures. In some embodiments, the target subcooling degree ΔToSCo of the outdoor heat exchanger 103=a×Ta+b, where a and b are constants, and Ta is the outdoor ambient temperature. For example, a≥0 (e.g., 3≤a≤30), b≤0 (e.g., −2≤b≤0), and 0° C.≤ΔToSCo≤15° C.

For example, the first target subcooling degree interval is related to the target subcooling degree ΔToSCo of the outdoor heat exchanger 103. For example, the lower limit of the first target subcooling degree interval may be referred to as ΔToSCo−λ1, and the upper limit of the first target subcooling degree interval may be referred to as ΔToSCo+λ1, where λ1>0, for example, 0° C.<λ1<3° C. That is, the first target subcooling degree interval may be referred to as [ΔToSCo−λ1, ΔToSCo+λ1].

Therefore, in a case where ΔToSC is greater than a sum of ΔToSCo and λ1 (i.e., ΔToSC>ΔToSCo+λ1), it indicates that ΔToSC is too great, and EVO needs to be increased to reduce ΔToSC. In a case where ΔToSC is less than the difference between ΔToSCo and λ1 (i.e., ΔToSC<ΔToSCo−λ1), it indicates that ΔToSC is too small, and EVO needs to be reduced to increase ΔToSC. In a case where ΔToSC is greater than or equal to the difference between ΔToSCo and λ1, and less than or equal to the sum of ΔToSCo and λ1 (i.e., ΔToSCo−λ1≤ΔToSC≤ΔToSCo+λ1), ΔToSC is within the first target subcooling degree interval, and the air conditioning system 1 is operating normally, so there is no need to adjust EVO.

For example, each time the controller 30 adjusts (increases or decreases) the opening degree of the outdoor electronic expansion valve 104, the adjustment amount may be in a range from 0.1% to 10% of the maximum opening degree of the outdoor electronic expansion valve 104 (e.g., including 0.1% and/or 10%). For example, if the adjustment amount of the opening degree of the outdoor electronic expansion valve 104 is referred to as ΔEVO, then 0.1%×EVO_max≤ΔEVO≤10%×EVO_max.

In some embodiments, the controller 30 is configured to increase the opening degree of the indoor electronic expansion valve 107 if the exhaust superheat degree of the compressor 102 is greater than the upper limit of the target exhaust superheat degree interval, reduce the opening degree of the indoor electronic expansion valve 107 if the exhaust superheat degree of the compressor 102 is less than the lower limit of the target exhaust superheat degree interval, and control the opening degree of the indoor electronic expansion valve 107 to remain unchanged if the exhaust superheat degree of the compressor 102 is greater than or equal to the lower limit of the target exhaust superheat degree interval and less than or equal to the upper limit of the target exhaust superheat degree interval.

For example, the exhaust superheat degree of the compressor 102 may be referred to as ΔTdSH, and the target exhaust superheat degree of the compressor 102 may be referred to as ΔTdSHo. The exhaust superheat degree ΔTdSH of the compressor 102 is equal to a difference between Td and Tc (i.e., ΔTdSH=Td−Tc), and Td represents the exhaust temperature of the compressor 102 detected by the compressor exhaust temperature sensor 115.

For example, the target exhaust superheat degree interval is related to the target exhaust superheat degree of the compressor 102, where the unit of the superheat degree is ° C. For example, the lower limit of the target exhaust superheat degree interval may be referred to as ΔTdSHo−δ, and the upper limit of the target exhaust superheat degree interval may be referred to as ΔTdSHo+δ, where ΔTdSHo is greater than or equal to 20 and less than or equal to 30 (i.e., 20≤ΔTdSHo≤30), δ is greater than 0 (i.e., δ>0; e.g., 0<δ<3). That is, the target exhaust superheat degree interval may be referred to as [ΔTdSHo−δ, ΔTdSHo+δ].

Therefore, in a case where ΔTdSH is greater than a sum of ΔTdSHo and δ (i.e., ΔTdSH>ΔTdSHo+δ), it indicates that ΔTdSH is too great, and EVI needs to be increased to reduce ΔTdSH. In a case where ΔTdSH is less than the difference between ΔTdSHo and δ (i.e., ΔTdSH<ΔTdSHo−δ), it indicates that ΔTdSH is too small, and EVI needs to be reduced to increase ΔTdSH. In a case where ΔTdSH is greater than or equal to a difference between ΔToSCo and λ1, and less than or equal to a sum of ΔToSCo and λ1 (i.e., ΔToSCo−λ1≤ΔTdSH≤ΔToSCo+λ1), ΔTdSH is within the first target subcooling degree interval, the air conditioning system 1 is operating normally, so there is no need to adjust EVI.

For example, each time the controller 30 adjusts (increases or decreases) the opening degree of the indoor electronic expansion valve 107, the adjustment amount may be in a range from 0.1% to 10% of the maximum opening degree of the indoor electronic expansion valve 107 (e.g., including 0.1% and/or 10%). For example, if the adjustment amount of the opening degree of the indoor electronic expansion valve 107 is referred to as ΔEVI, then 0.1% EVI_max≤ΔEVI≤10% EVI_max.

For example, the control process of the controller 30 in a case where the first preset condition is satisfied may be referred to as a control mode a. In a case where the air conditioning system 1 is in the cooling mode and the first preset condition is satisfied, the controller 30 enters the control mode a, controls the subcooling degree of the outdoor heat exchanger 103 to be within the first target subcooling degree interval, and controls the exhaust superheat degree of the compressor 102 to be within the target exhaust superheat degree interval by adjusting the opening degrees of the indoor electronic expansion valve 107 and the outdoor electronic expansion valve 104. In this way, it may be ensured that the refrigerant in the unit connecting liquid pipe 106 is in the two-phase state. Therefore, in a case where the amount of refrigerant in the air conditioning system 1 is insufficient, it may further be ensured that the cooling capacity of the air conditioning system 1 is maintained at a high level, and the refrigerant free addition in the air conditioning system 1 may be implemented. In this case, stable operation of the air conditioning system 1 may further be ensured by adjusting the opening degrees of the indoor electronic expansion valve 107 and the outdoor electronic expansion valve 104.

The control mode a will be illustrated below with reference to FIG. 5.

In step 51, the indoor electronic expansion valve 107 and the outdoor electronic expansion valve 104 respectively operate at current opening degrees.

For example, in a case where the air conditioning system 1 is operating in an n-th cycle, the opening degree of the indoor electronic expansion valve 107 may be referred to as EVI(n), and the opening degree of the outdoor electronic expansion valve may be referred to as EVO(n).

In step 52, it is determined whether ΔToSC−ΔToSCo>λ1 is satisfied.

If so, it indicates that the subcooling degree ΔToSC of the outdoor heat exchanger 103 is greater than the upper limit ΔToSCo+λ1 of the first target subcooling degree interval. In this case, EVO needs to be increased to reduce the subcooling degree of the outdoor heat exchanger 103, so that the subcooling degree of the outdoor heat exchanger 103 is within the first target subcooling degree interval, therefore, step 521 is performed. If not, step 53 is performed.

In step 521, it is determined whether EVO(n)<EVO_max is satisfied.

If so, it indicates that the current opening degree EVO(n) of the outdoor electronic expansion valve 104 has not reached the maximum opening degree EVO_max of the outdoor electronic expansion valve 104, and there is room for increase, and step 522 is performed. If not, it indicates that the outdoor electronic expansion valve 104 has currently reached the maximum opening degree EVO_max, and there is no room for increase, and step 523 is performed.

In step 522, EVO(n+1)=EVO(n)+ΔEVO₁.

In a case where the air conditioning system 1 enters a next cycle (i.e., an (n+1)-th cycle), the opening degree of the outdoor electronic expansion valve 104 will be increased. For example, EVO(n+1)=EVO(n)+ΔEVO₁, where ΔEVO₁ is an increase value of the opening degree of the outdoor electronic expansion valve 104.

In step 523, EVO(n+1)=EVO_max.

In a case where the air conditioning system 1 enters the (n+1)-th cycle, the opening degree EVO(n+1) of the outdoor electronic expansion valve 104 is maintained at EVO_max.

In step 53, it is determined whether ΔToSC−ΔToSCo<−λ1 is satisfied.

If so, it indicates that the subcooling degree ΔToSC of the outdoor heat exchanger 103 is less than the lower limit value ΔToSCo−λ1 of the first target subcooling degree interval. In this case, the opening degree EVO of the outdoor electronic expansion valve 104 needs to be reduced to increase the subcooling degree of the outdoor heat exchanger 103, so that the subcooling degree of the outdoor heat exchanger 103 is within the first target subcooling degree interval. Therefore, step 531 is performed. If not, step 54 is performed.

In step 531, it is determined whether EVO(n)>EVO_min is satisfied.

If so, it indicates that the current opening degree EVO(n) of the outdoor electronic expansion valve 104 has not reached the minimum opening degree EVO_min of the outdoor electronic expansion valve 104, and there is room for reduction, and step 532 is performed. If not, it indicates that the outdoor electronic expansion valve 104 has reached the minimum opening degree EVO_min, there is no room for reduction, and step 533 is performed.

In step 532, EVO(n+1)=EVO(n)−ΔEVO₂.

In the (n+1)-th cycle, the opening degree of the outdoor electronic expansion valve 104 is reduced. For example, EVO(n+1)=EVO(n)−ΔEVO₂, where ΔEVO₂ is the reduction value of the opening degree of the outdoor electronic expansion valve 104.

In step 533, EVO(n+1)=EVO_min.

In the (n+1)-th cycle, the opening degree EVO(n+1) of the outdoor electronic expansion valve 104 is maintained at EVO_min.

In step 54, EVO(n+1)=EVO(n).

In this case, it indicates that the subcooling degree of the outdoor heat exchanger 103 is within the first target subcooling degree interval. That is, −λ1≤ΔToSC−ΔToSCo≤λ1 is satisfied. Therefore, in the (n+1)-th cycle, the outdoor electronic expansion valve 104 may be controlled to maintain the opening degree of the previous cycle (i.e., the n-th cycle), that is, EVO(n+1)=EVO(n).

In step 55, it is determined whether ΔTdSH−ΔTdSHo>δ is satisfied.

If so, it indicates that the exhaust superheat degree ΔTdSH of the compressor 102 is greater than the upper limit ΔTdSHo+δ of the target exhaust superheat degree interval. In this case, the opening degree EVI of the indoor electronic expansion valve 107 needs to be increased to reduce the exhaust superheat degree ΔTdSH of the compressor 102. Therefore, step 551 is performed; if not, step 56 is performed.

In step 551, it is determined whether EVI(n)<EVI_max is satisfied.

If so, it indicates that the current opening degree EVI(n) of the indoor electronic expansion valve 107 has not reached the maximum opening degree EVI_max of the indoor electronic expansion valve 107, there is room for increase, and step 552 is performed. If not, it indicates that the indoor electronic expansion valve 107 has currently reached the maximum opening degree EVI_max, there is no room for increase, and step 553 is performed.

In step 552, EVI(n+1)=EVI(n)+ΔEVI₁.

In the (n+1)-th cycle, the opening degree of the indoor electronic expansion valve 107 is increased. For example, EVI(n+1)=EVI(n)+ΔEVI₁, where ΔEVI₁ is the increase value of the opening degree of the indoor electronic expansion valve 107.

In step 553, EVI(n+1)=EVI_max.

In the (n+1)-th cycle, the opening degree EVI(n+1) of the indoor electronic expansion valve 107 is maintained at EVI_max.

In step 56, it is determined whether ΔTdSH−ΔTdSHo<−δ is satisfied.

If so, it indicates that the exhaust superheat degree ΔTdSH of the compressor 102 is less than the lower limit ΔTdSHo−δ of the target exhaust superheat degree interval. In this case, the opening degree EVO of the indoor electronic expansion valve 107 needs to be reduced to increase the exhaust superheat degree ΔTdSH of the compressor 102. Therefore, step 561 is performed. If not, step 57 is performed.

In step 561, it is determined whether EVI(n)>EVI_min is satisfied.

If so, it indicates that the current opening degree EVO(n) of the indoor electronic expansion valve 107 has not reached the minimum opening degree of the indoor electronic expansion valve 107, and there is still room for reduction, and step 562 is performed. If not, it indicates that the indoor electronic expansion valve 107 has currently reached the minimum opening degree EVI_min, and there is no room for reduction, so that step 563 is performed.

In step 562, EVI(n+1)=EVI(n)−ΔEVI₂.

Therefore, in the (n+1)-th cycle, the opening degree of the indoor electronic expansion valve 107 is reduced. For example, EVI(n+1)=EVI(n)−ΔEVI₂, where ΔEVI₂ is the decrease value of the opening degree of the indoor electronic expansion valve 107.

In step 563, EVI(n+1)=EVI_min.

In the (n+1)-th cycle, the opening degree EVI(n+1) of the indoor electronic expansion valve 107 is maintained at EVI_min.

In step 57, EVI(n+1)=EVI(n).

In a case where the exhaust superheat degree of the compressor 102 is within the target exhaust superheat degree interval, that is, in a case where −δ≤ΔTdSH−ΔTdSHo≤δ is satisfied, the indoor electronic expansion valve 107 may be controlled to maintain at the opening degree EVI(n) in the n-th cycle in the (n+1)-th cycle. That is, EVI(n+1)=EVI(n).

The controller 30 is configured to adjust the opening degrees of the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval in a case where the first preset condition is not satisfied.

It will be noted that in a case where the exhaust superheat degree of the compressor 102 is not within the target exhaust superheat degree interval, it indicates that the current operation of the compressor 102 is unstable and the air conditioning system 1 may malfunction. Therefore, it is necessary to adjust the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107, so as to control the exhaust superheat degree of the compressor 102 to remain within the target exhaust superheat degree interval, thereby ensuring the stable operation of the air conditioning system 1.

In some embodiments, the controller 30 is configured to increase the opening degrees of the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 if the exhaust superheat degree of the compressor 102 is greater than the upper limit of the target exhaust superheat degree interval, reduce the opening degrees of the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 if the exhaust superheat degree of the compressor 102 is less than the lower limit of the target exhaust superheat degree interval, and control the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 to maintain the current opening degrees if the exhaust superheat degree of the compressor 102 is within the target exhaust superheat degree interval.

For example, the controller 30 may first adjust the opening degree of the outdoor electronic expansion valve 104 and then adjust the opening degree of the indoor electronic expansion valve 107 according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval. The process that the controller 30 adjusts the opening degree of the indoor electronic expansion valve 107 according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval is similar to the process that the controller 30 adjusts the opening degree of the outdoor electronic expansion valve 104 according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval in some of the above embodiments, and details will not be repeated herein.

For example, the control process of the controller 30 in a case where the first preset condition is not satisfied may be referred to as a control mode b. In a case where the first preset condition is not satisfied, it indicates that the opening degree of the indoor electronic expansion valve 107 in one or more operating indoor units in air conditioning system 1 is greater than or equal to the first preset opening degree. In this case, the indoor electronic expansion valve 107 is approaching the fully open state and is in an uncontrollable state. Therefore, the stability of the air conditioning system 1 will be affected. In this case, the controller 30 may enter the control mode b and adjust the opening degrees of the indoor electronic expansion valve 107 and the outdoor electronic expansion valve 104, so that the exhaust superheat degree of the compressor 102 is within the target exhaust superheat degree interval, so as to ensure the stable operation of the compressor 102. Therefore, the stable operation of the air conditioning system 1 is ensured.

The operation process of the control mode b will be illustrated below with reference to FIG. 6.

In step 61, the indoor electronic expansion valve 107 and the outdoor electronic expansion valve 104 respectively operate at a current opening degree.

It is similar to step 51 in the above embodiments, and details will not be repeated herein.

In step 62, it is determined whether ΔTdSH−ΔTdSHo>δ is satisfied.

It is similar to step 55 in the above embodiments, and details will not be repeated herein. If so, step 621 is performed; if not, step 63 is performed.

In step 621, it is determined whether the condition EVO(n)<EVO_max is satisfied.

It is similar to step 521 in the above embodiments, and details will not be repeated herein. If so, step 622 is performed; if not, step 623 is performed.

In step 622, EVO(n+1)=EVO(n)+ΔEVO₁.

In step 623, EVO(n+1)=EVO_max.

In step 63, it is determined whether ΔTdSH−ΔTdSHo<−δ is satisfied.

It is similar to step 56 in the above embodiments, and details will not be repeated herein. If so, step 631 is performed; if not, step 64 is performed.

In step 631, it is determined whether EVO(n)>EVO_min is satisfied.

It is similar to step 531 in the above embodiments, and details will not be repeated herein. If so, step 632 is performed; if not, step 632 is performed.

In step 632, EVO(n+1)=EVO(n)−ΔEVO₂.

In step 633, EVO(n+1)=EVO_min.

In step 64, EVO(n+1)=EVO(n).

In step 65, it is determined whether ΔTdSH−ΔTdSHo>δ is satisfied.

It is similar to step 55 in the above embodiments, and details will not be repeated herein. If so, step 651 is performed; if not, step 66 is performed.

In step 651, it is determined whether EVI(n)<EVI_max is satisfied.

It is similar to step 551 in the above embodiments, and details will not be repeated herein. If so, step 652 is performed; if not, step 653 is performed.

In step 652, EVI(n+1)=EVI(n)+ΔEVI₁.

In step 653, EVI(n+1)=EVI_max.

In step 66, it is determined whether ΔTdSH−ΔTdSHo<−δ is satisfied.

It is similar to step 56 in the above embodiments, and details will not be repeated herein. If so, step 651 is performed; if not, step 66 is performed.

In step 661, it is determined whether EVI(n)>EVI_min is satisfied.

It is similar to step 561 in the above embodiments, and details will not be repeated herein. If so, step 662 is performed; if not, step 663 is performed.

In step 662, EVI(n+1)=EVI(n)−ΔEVI₂.

In step 663, EVI(n+1)=EVI_min.

In step 67, EVI(n+1)=EVI(n).

In some embodiments, the controller 30 is configured to adjust the opening degrees of the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval in a case where both the first preset condition and the second preset condition are satisfied. In a case where the first preset condition is satisfied and the second preset condition is not satisfied, the controller 30 adjusts the opening degree of outdoor electronic expansion valve 104 according to the relationship between the subcooling degree of the outdoor heat exchanger 103 and the first target subcooling degree interval, and adjusts the opening degree of the indoor electronic expansion valve 107 according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval.

In some embodiments, the second preset condition includes that an opening degree of a target indoor electronic expansion valve in a target indoor unit is greater than or equal to a second preset opening degree, a superheat degree of a target indoor heat exchanger in the target indoor unit is greater than or equal to a target superheat degree, and the exhaust superheat degree of the compressor 102 is greater than or equal to the upper limit of the target exhaust superheat degree interval.

For example, the target indoor unit is one of the plurality of indoor units 20. Therefore, the target indoor electronic expansion valve is one of the plurality of indoor electronic expansion valves 107. For example, the target indoor electronic expansion valve is the indoor electronic expansion valve 1071 or the indoor electronic expansion valve 1072. The target heat exchanger is one of the plurality of indoor heat exchangers 108. For example, the target indoor heat exchanger is the indoor heat exchanger 1081 or the indoor heat exchanger 1082.

It will be noted that the indoor heat exchanger 108 is used as an evaporator in the cooling mode. If the opening degree EVI of the indoor electronic expansion valve 107 of the evaporator is greater than the second preset opening degree, that is, the indoor electronic expansion valve 107 is approaching fully open state, the superheat degree of the indoor heat exchanger 108 will be too great. In a case where the exhaust superheat degree of the compressor 102 is greater than the upper limit of the target exhaust superheat degree interval, it indicates that superheat degree of at least one indoor heat exchanger 108 is uncontrollable, which may cause the compressor 102 to malfunction stably.

The control mode a and the control mode b in the above embodiments are taken as examples. That is, after the air conditioning system 1 performs the control mode a, it needs to determine whether the second preset condition is satisfied. If the second preset condition is satisfied, the air conditioning system 1 re-performs control mode a. If the second preset condition is not satisfied, the air conditioning system 1 enters the control mode b.

In some embodiments, the second preset opening degree is greater than the first preset opening degree. For example, the second preset opening degree may be 97% of the maximum opening degree value of the indoor electronic expansion valve 107.

For example, the superheat degree of the target indoor heat exchanger may be referred to as ASH, where ASH is equal to a difference between Tg and TI (i.e., ΔSH=Tg−TI), Tg represents the temperature of the unit connecting air pipe 109 detected by the third temperature sensor 117, and TI represents the temperature of the unit connecting liquid pipe 106 detected by the second temperature sensor 116.

Hereinafter, the control process of the controller 30 when the air conditioning system 1 is in the cooling mode will be illustrated below with reference to FIG. 7.

In step 71, the opening degree EVI of the indoor electronic expansion valve 107 is obtained.

For example, in the n-th cycle, the opening degrees of the plurality of indoor electronic expansion valves 107 are obtained as EVI(n).

In step 72, it is determined whether the first preset condition is satisfied.

For example, it is determined whether the opening degree EVI(n) of the indoor electronic expansion valve 107 is less than 90%×EVI_max, where 90%×EVI_max represents the first preset opening degree. If so, step 73 is performed; if not, step 75 is performed.

In step 73, control mode a is operated.

Step 51 to step 57 in the above embodiments are performed.

In step 74, it is determined whether the second preset condition is satisfied.

For example, it is determined whether the superheat degree of the target indoor heat exchanger is greater than the target superheat degree, whether the opening degree of the target indoor electronic expansion valve is greater than the first preset opening degree, and whether the exhaust superheat degree of the compressor 102 is greater than the upper limit of the target exhaust superheat degree interval. That is, it is determined whether the conditions ΔSH>e, at least one EVI(n)>97%×EVI_max, and ΔTdSH−ΔTdSHo>δ+d are satisfied, where d>0 (e.g., 5° C.<d<10° C.), e>0 (e.g., 2° C.<e<5° C.). If so, step 73 is performed; if not, step 75 is performed.

In step 75, control mode b is operated.

Step 61 to step 67 in the above embodiments are performed.

In summary, in a case where the air conditioning system 1 provided by some embodiments of the present disclosure operates in the cooling mode, the air conditioning system 1 may obtain the operating states of the indoor heat exchanger 108 and the compressor 102 by determining whether the first preset condition and the second preset condition are satisfied, and adjust the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval and/or the relationship between the subcooling degree of the outdoor heat exchanger 103 and the target subcooling degree, so that the subcooling degree of the outdoor heat exchanger 103 is within the first target subcooling degree interval, and the exhaust superheat degree of the compressor 102 is within the target exhaust superheat degree interval. Therefore, it is possible to avoid adding additional refrigerant to air conditioning system 1, the stable operation of the air conditioning system 1 may be ensured and the reliability of the air conditioning system 1 may be improved.

In some embodiments, the compressor 102 compresses the refrigerant and discharges the compressed refrigerant, and the indoor heat exchanger 108 condenses the compressed refrigerant. The indoor electronic expansion valve 107 and the outdoor electronic expansion valve 104 adjust the amount of refrigerant condensed by the outdoor heat exchanger 103 in sequence, and the outdoor heat exchanger 103 evaporates the refrigerant adjusted by the outdoor electronic expansion valve 104. The controller 30 is further configured to obtain the opening degree of the outdoor electronic expansion valve 104, adjust the opening degree of the indoor electronic expansion valve 107 according to the relationship between the subcooling degree of the indoor heat exchanger 108 and the second target subcooling degree interval in a case where a third preset condition is satisfied, and adjust the opening degree of the outdoor electronic expansion valve 104 according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval.

In some embodiments, the third preset condition includes that the opening degree of the outdoor electronic expansion valve 104 is less than a third preset opening degree.

In a case where the air conditioning system 1 operates in the heating mode, the outdoor heat exchanger 103 evaporates the refrigerant. The controller 30 obtains the opening degree of the outdoor electronic expansion valve 104 and determines whether the opening degree of the outdoor electronic expansion valve 104 is less than the third preset opening degree.

In some embodiments, the third preset opening degree is less than the maximum opening degree of the outdoor electronic expansion valve 104. For example, the third preset opening degree may be 90% of the maximum opening degree of the outdoor electronic expansion valve 104.

The opening degree of the outdoor electronic expansion valve 104 is less than the third preset opening degree, indicating that there is room for adjusting the opening degree of the outdoor electronic expansion valve 104. In this case, the controller 30 may adjust the opening degree of the indoor electronic expansion valve 107 according to the relationship between the subcooling degree of the indoor heat exchanger 108 and the second target subcooling degree interval and adjust the opening degree of the outdoor electronic expansion valve 104 according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval.

For example, the subcooling degree of the indoor heat exchanger 108 may be referred to as ΔTiSC, and the target subcooling degree of the indoor heat exchanger 108 may be referred to as ΔTiSCo. The subcooling degree ΔTiSC of the indoor heat exchanger 108 is equal to a difference between Tc and TI (i.e., ΔTiSC=Tc−TI). For example, the target subcooling degree ΔTiSCo of the indoor heat exchanger 108 may be set differently according to an air cooling ratio, where the air cooling ratio is used to indicate a ratio between air volume and capacity of the indoor unit 20. For example, in a case where the air cooling ratio is large, the air outlet temperature of the indoor unit is low. In this case, in order to prevent cold air from coming out, the target subcooling degree ΔTiSCo may be set lower. For example, ΔTiSCo may be set in a range from 5° C. to 8° C. In a case where the air cooling ratio is small, the target subcooling degree ΔTiSCo may be set higher. For example, ΔTiSCo may be set in a range from 12° C. to 20° C.

For example, the second target subcooling degree interval is related to the target subcooling degree ΔTiSCo of the indoor heat exchanger 108. For example, a lower limit of the second target subcooling degree interval may be referred to as ΔTiSCo−λ2, and an upper limit of the second target subcooling degree interval may be referred to as ΔTiSCo+λ2, where λ2 may be the same as λ1, that is, the second target subcooling degree interval may be referred to as [ΔTiSCo−λ2, ΔTiSCo+λ2].

It will be noted that in a case where the air conditioning system 1 operates in the heating mode, the indoor heat exchanger 108 operates as a condenser, and the subcooling degree of the indoor heat exchanger 108 may be controlled by adjusting the opening degree of the indoor electronic expansion valve 107. The outdoor heat exchanger 103 operates as an evaporator, and the superheat degree of the outdoor heat exchanger 103 and the exhaust superheat degree of the compressor 102 may be adjusted by adjusting the opening degree of the outdoor electronic expansion valve 104.

In some embodiments, the controller 30 is configured to increase the opening degree of the indoor electronic expansion valve 107 if the subcooling degree of the indoor heat exchanger 108 is greater than the upper limit of the second target subcooling degree interval, reduce the opening degree of the indoor electronic expansion valve 107 if the subcooling degree of the indoor heat exchanger 108 is less than the lower limit of the second target subcooling degree interval, and control the opening degree of the indoor electronic expansion valve 107 to remain unchanged if the subcooling degree of the indoor heat exchanger 108 is greater than or equal to the lower limit of the second target subcooling degree interval, and is less than or equal to the upper limit of the second target subcooling degree interval.

That is, in a case where ΔTiSC is greater than a sum of ΔTiSCo and λ2 (i.e., ΔTiSC>ΔTiSCo+λ2), it indicates that the subcooling degree ΔTiSC of the indoor heat exchanger 108 is too great. Therefore, EVI needs to be increased to reduce ΔTiSC. In a case where ΔTiSC is less than a difference between ΔTiSCo and λ2 (i.e., ΔTiSC<ΔTiSCo−λ2), it indicates that the subcooling degree ΔTiSC of the indoor heat exchanger 108 is too small, so EVI needs to be reduced to increase ΔTiSC. In a case where ΔTiSC is greater than or equal to a difference between ΔTiSCo and λ2, and less than or equal to a sum of ΔTiSCo and λ2 (i.e., ΔTiSCo−λ2≤ΔTiSC≤ΔTiSCo+λ2), ΔTiSC is within the second target subcooling degree interval, the air conditioning system 1 is operating normally, so there is no need to adjust EVI.

In some embodiments, the controller 30 is configured to increase the opening degree of the outdoor electronic expansion valve 104 if the exhaust superheat degree of the compressor 102 is greater than the upper limit of the target exhaust superheat degree interval, reduce the opening degree of the outdoor electronic expansion valve 104 if the exhaust superheat degree of the compressor 102 is less than the lower limit of the target exhaust superheat degree interval, and control the opening degree of the outdoor electronic expansion valve 104 to remain unchanged if the exhaust superheat degree of the compressor 102 is greater than or equal to the lower limit of the target exhaust superheat degree interval and less than or equal to the upper limit of the target exhaust superheat degree interval.

For example, the control process of the controller 30 in a case where the third preset condition is satisfied may be referred to as a control mode c. In a case where the air conditioning system 1 operates in the heating mode and the third preset condition is satisfied, the controller 30 enters the control mode c, and the operating status of the outdoor electronic expansion valve 104 may be obtained by determining whether the opening degree of the outdoor electronic expansion valve 104 is less than the third preset opening degree. In a case where the opening degree of the outdoor electronic expansion valve 104 is less than the third preset opening degree, it indicates that the air conditioning system 1 is operating stably. By adjusting the opening degrees of the indoor electronic expansion valve 107 and the outdoor electronic expansion valve 104, the subcooling degree of the indoor heat exchanger 108 is controlled to be within the second target subcooling degree interval, and the exhaust superheat degree of the compressor 102 is controlled to be within the target exhaust superheat degree interval. Therefore, even in a case where the amount of refrigerant in the air conditioning system 1 is insufficient, the normal operation of the air conditioning system 1 can be ensured.

The operation process of the control mode c will be illustrated below with reference to FIG. 8.

In step 81, the indoor electronic expansion valve 107 and the outdoor electronic expansion valve 104 respectively operate at a current opening degree.

It is similar to step 51 in the above embodiments, and details will not be repeated herein.

In step 82, it is determined whether ΔTiSC−ΔTiSCo>λ2 is satisfied.

If so, it indicates that the subcooling degree ΔTiSC of the indoor heat exchanger 108 is greater than the upper limit ΔTiSCo+λ2 of the second target subcooling degree interval. In this case, EVI needs to be increased to reduce the subcooling degree of the indoor heat exchanger 108, so that the subcooling degree of the indoor heat exchanger 108 is within the second target subcooling degree interval, therefore, step 821 is performed. If not, step 83 is performed.

In step 821, it is determined whether EVI(n)<EVI_max is satisfied.

It is similar to step 551 in the above embodiments, and details will not be repeated herein. If so, step 822 is performed; if not, step 823 is performed.

In step 822, EVI(n+1)=EVI(n)+ΔEVI₁.

In step 823, EVI(n+1)=EVI_max.

In step 83, it is determined whether ΔTiSC−ΔTiSCo<−λ2 is satisfied.

If so, it indicates that the subcooling degree ΔTiSC of the indoor heat exchanger 108 is less than the lower limit ΔTiSCo−λ2 of the second target subcooling degree interval. In this case, the EVI needs to be reduced to increase the subcooling degree of the indoor heat exchanger 108, so that the subcooling degree of the indoor heat exchanger 108 is within the second target subcooling degree interval. Therefore, step 831 is performed. If not, step 84 is performed.

In step 831, it is determined whether EVI(n)>EVI_min is satisfied.

It is similar to step 561 in the above embodiments, and details will not be repeated herein. If so, step 832 is performed; if not, step 833 is performed.

In step 832, EVI(n+1)=EVI(n)−ΔEVI₂.

In step 833, EVI(n+1)=EVI_min.

In step 84, EVI(n+1)=EVI(n).

In step 85, it is determined whether ΔTdSH−ΔTdSHo>δ is satisfied.

It is similar to step 55 in the above embodiments, and details will not be repeated herein. If so, step 851 is performed; if not, step 86 is performed.

In step 851, it is determined whether EVO(n)<EVO_max is satisfied.

It is similar to step 521 in the above embodiments, and details will not be repeated herein. If so, step 852 is performed; if not, step 853 is performed.

In step 852, EVO(n+1)=EVO(n)+ΔEVO₁.

In step 853, EVO(n+1)=EVO_max.

In step 86, it is determined whether ΔTdSH−ΔTdSHo<−δ is satisfied.

It is similar to step 56 in the above embodiments, and details will not be repeated herein. If so, step 861 is performed; if not, step 87 is performed.

In step 861, it is determined whether EVO(n)>EVO_min is satisfied.

It is similar to step 531 in the above embodiments, and details will not be repeated herein. If so, step 862 is performed; if not, step 863 is performed.

In step 862, EVO(n+1)=EVO(n)−ΔEVO₂.

In step 863, EVO(n+1)=EVO_min.

In step 87, EVO(n+1)=EVO(n).

In some embodiments, the controller 30 is further configured to adjust the opening degrees of the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval in a case where the third preset condition is not satisfied.

For example, the controller 30 may first adjust the opening degree of the indoor electronic expansion valve 107 and then adjust the opening degree of the outdoor electronic expansion valve 104 according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval. In a case where the third preset condition is not satisfied, the control process of the controller 30 is similar to the control process in a case where the first preset condition is not satisfied in the above embodiment and will not be described again here.

For example, the control process of the controller 30 in a case where the third preset condition is not satisfied may be referred to as a control mode d. In a case where the air conditioning system 1 operates in the heating mode, and the third preset condition is not satisfied, it indicates that the outdoor electronic expansion valve 104 is approaching fully open and is in an uncontrollable state, and the stability of the air conditioning system 1 is affected. In this case, the controller 30 will enter the control mode d and adjust the opening degrees of the indoor electronic expansion valve 107 and the outdoor electronic expansion valve 104, so that the exhaust superheat degree of the compressor 102 is within the target exhaust superheat degree interval, so as to ensure the stable operation of the compressor 102, thereby ensuring the stable operation of the air conditioning system 1.

The operation process of the control mode d will be illustrated below with reference to FIG. 9. As shown in FIG. 9, the control mode d includes step 91 to step 97. Step 92 to step 94 are similar to step 65 to step 67 in the above embodiments, and step 95 to step 97 are similar to step 62 to step 64 in the above embodiments.

In step 91, the indoor electronic expansion valve 107 and the outdoor electronic expansion valve 104 respectively operate at a current opening degree.

In step 92, it is determined whether ΔTdSH−ΔTdSHo>δ is satisfied.

If so, step 921 is performed; if not, step 93 is performed.

In step 921, it is determined whether EVI(n)<EVI_max is satisfied.

If so, step 922 is performed; if not, step 923 is performed.

In step 922, EVI(n+1)=EVI(n)+ΔEVI₁.

In step 923, EVI(n+1)=EVI_max.

In step 93, it is determined whether ΔTdSH−ΔTdSHo<−δ is satisfied.

If so, step 931 is performed; if not, step 94 is performed.

In step 931, it is determined whether EVI(n)>EVI_min is satisfied.

If so, step 932 is performed; if not, step 933 is performed.

In step 932, EVI(n+1)=EVI(n)−ΔEVI₂.

In step 933, EVI(n+1)=EVI_min.

In step 94, EVI(n+1)=EVI(n).

In step 95, it is determined whether ΔTdSH−ΔTdSHo>δ is satisfied.

If so, step 951 is performed; if not, step 96 is performed.

In step 951, it is determined whether EVO(n)<EVO_max is satisfied.

If so, step 952 is performed; if not, step 953 is performed.

In step 952, EVO(n+1)=EVO(n)+ΔEVO₁.

In step 953, EVO(n+1)=EVO_max.

In step 96, it is determined whether ΔTdSH−ΔTdSHo<−δ is satisfied.

If so, step 961 is performed; if not, step 97 is performed.

In step 961, it is determined whether EVO(n)>EVO_min is satisfied.

If so, step 962 is performed; if not, step 963 is performed.

In step 962, EVO(n+1)=EVO(n)−ΔEVO₂.

In step 963, EVO(n+1)=EVO_min.

In step 97, EVO(n+1)=EVO(n).

In some embodiments, the controller 30 is configured to adjust the opening degrees of the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval in a case where the third preset condition and a fourth preset condition are satisfied. In a case where the third preset condition is satisfied and the fourth preset condition is not satisfied, the opening degree of the indoor electronic expansion valve 107 is adjusted according to the relationship between the subcooling degree of the indoor heat exchanger 108 and the second target subcooling degree interval, and the opening degree of the outdoor electronic expansion valve 104 is adjusted according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval.

In some embodiments, the fourth preset condition includes that the opening degree of the outdoor electronic expansion valve 104 is greater than or equal to the fourth preset opening degree, and the exhaust superheat degree of the compressor 102 is greater than or equal to the upper limit of the target exhaust superheat degree interval.

It will be noted that in the heating mode, the outdoor heat exchanger 103 is used as an evaporator. If the opening degree EVO of the outdoor electronic expansion valve 104 of the evaporator is greater than the fourth preset opening degree, the outdoor electronic expansion valve 104 is almost in a fully open state and the exhaust superheat degree of compressor 102 is greater than the upper limit of the target exhaust superheat degree interval, which indicates that the compressor 102 in the air conditioning system 1 is uncontrollable and the operation of air conditioning system 1 is unstable. In this case, the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 need to be adjusted to ensure the stable operation of the air conditioning system 1.

In the above embodiments, the control mode c and the control mode d are taken as examples. That is, after performing the control mode c, the air conditioning system 1 still needs to determine whether the fourth preset condition is satisfied. If the fourth preset condition is satisfied, the air conditioning system 1 re-performs the control mode c. If the fourth preset condition is not satisfied, the air conditioning system 1 enters the control mode d.

In some embodiments, the fourth preset opening degree is greater than the third preset opening degree. For example, the fourth preset opening degree may be 95% of the maximum opening degree of the outdoor electronic expansion valve.

In some embodiments, the first preset opening degree, the second preset opening degree, the third preset opening degree, and the fourth preset opening degree may be obtained through a large number of tests.

Hereinafter, the control process of the controller 30 when the air conditioning system 1 is in the heating mode will be illustrated below with reference to FIG. 10.

In step 101, the opening degree EVO of the outdoor electronic expansion valve 104 is obtained.

In step 102, it is determined whether the third preset condition is satisfied.

For example, it is determined whether the opening degree EVO(n) of the outdoor electronic expansion valve 104 is less than 90%×EVO_max. That is, it is determined that the condition EVO(n)<90%×EVO_max is satisfied, where 90%×EVO_max represents the third preset opening degree. If so, step 103 is performed; if not, step 105 is performed.

In step 103, control mode c is performed.

Step 81 to step 87 in the above embodiments are performed.

In step 104, it is determined whether the fourth preset condition is satisfied.

For example, it is determined that the opening degree of the outdoor electronic expansion valve is greater than the fourth preset opening degree, and the exhaust superheat degree of the compressor 102 is greater than the upper limit of the target exhaust superheat degree interval. That is, it is determined whether the conditions EVO(n)>95%×EVO_max and ΔTdSH−ΔTdSHo>δ+d are satisfied. If so, step 103 is performed; if not, step 105 is performed.

In step 105, control mode d is performed.

Step 91 to step 97 in the above embodiments are performed.

In some embodiments, as shown in FIG. 11, the air conditioning system 1 further includes a plurality of indoor units 20 (e.g., three indoor units 30) and a plurality of branch pipes 40 (e.g., four branch pipes 40). The four branch pipes 40 may include two liquid phase branch pipes 41 and two gas phase branch pipes 42. As shown in FIG. 11, a direction from X to X′ may be referred to as a first direction. For example, the first direction may further be a direction from left (X) to right (X′). A direction from Y to Y′ may be referred to as a second direction. For example, the second direction may be a direction from front (Y) to rear (Y′). The two liquid phase branch pipes 41 are located at a side of the indoor unit 20 (e.g., the Y side), and the two gas phase branch pipes 42 are located at another side of the indoor unit 20 (e.g., the Y′ side).

For example, as shown in FIG. 11, the liquid phase branch pipe 41 may include a first flow pipe 411 and two second flow pipes 412, and ends of the two second flow pipes 412 may be communicated to a same end of the first flow pipe 411. Correspondingly, the two gas phase branch pipes 42 may include a third flow pipe 421 and two fourth flow pipes 422, and ends of the two fourth flow pipes 422 may be communicated to a same end of the third flow pipe 421.

Continuing to refer to FIG. 11, when connecting the outdoor electronic expansion valve 104 and the three indoor units 20, the end of the first flow pipe 411 of the liquid phase branch pipe 41 located at the X side away from the second flow pipe 412 may be communicated to the outdoor electronic expansion valve 104, which may be directly communicated or communicated through a refrigerant pipe (e.g., a steel pipe or an aluminum pipe). An end of one second flow pipe 412 of the liquid phase branch pipe 41 at the X side away from the first flow pipe may be communicated to an end (e.g., a front end) of the first indoor electronic expansion valve 1071, and another second flow pipe 412 may be communicated to the first flow pipe 411 of the liquid phase branch pipe 41 at the X′ side. In addition, the two second flow pipes 412 of the liquid phase branch pipe 41 at the X′ side may be communicated to an end of the second indoor electronic expansion valve 1072 and an end of the third indoor electronic expansion valve 1073, respectively, thereby implementing communication between the outdoor electronic expansion valve 104 and the three indoor units 20.

Continuing to refer to FIG. 11, when connecting the four-way valve 111 with the three indoor units 20, an end of the third flow pipe 421 of the gas phase branch pipe 42 located at the X side away from the fourth flow pipe 422 may be communicated to an end of the four-way valve 111, which may be directly communicated or communicated through a refrigerant pipe. An end of one fourth flow pipe 422 of the gas phase branch pipe 42 at the X-side away from the third flow pipe 421 may be communicated to a rear end of the first indoor heat exchanger 1081 of the indoor unit at the X side, and another fourth flow pipe 422 may be communicated to the third flow pipe 421 of the gas phase branch pipe 42 at the X′ side, correspondingly. In addition, the two fourth flow pipes 422 of the gas phase branch pipe 42 at the X′ side may be communicated to a rear end of the second indoor heat exchanger 1082 and a rear end of the third indoor heat exchanger 1083 respectively, thereby implementing the communication between the four-way valve 111 and the three indoor units 20.

In some embodiments, when the air conditioning system 1 operates in cooling mode, in a case where the charging amount of refrigerant is small, or in a case where the gas phase refrigerant is not capable of being completely converted into liquid phase refrigerant, the refrigerant flows from the outdoor heat exchanger 103 to the liquid phase branch pipe 41 is generally a gas-liquid two-phase refrigerant. During a process of the gas-liquid two-phase refrigerant being branched from the liquid phase branch pipe 41 to the plurality of indoor units 20, due to the differences in the installation heights of the plurality of indoor units 20 and the lengths of the refrigerant pipes communicated to the outdoor units 10, the liquid phase refrigerant and the gas phase refrigerant are gradually separated after the gas-liquid two-phase refrigerant is branched through one or more liquid phase branch pipes 41, and a large amount of the gas phase refrigerant will be concentrated in the indoor heat exchanger 108 of one or more indoor units 20, which will significantly reduce the amount of refrigerant flowing through the part of indoor heat exchangers 108, resulting in a sharp decrease in the cooling capacity of the part of indoor units 20.

In view of this, as shown in FIG. 11, the subcooling degree of the outdoor heat exchanger 103 may be obtained from the temperature detected by the first temperature sensor 113. In some embodiments, in a case where the subcooling degree of the outdoor heat exchanger 103 is greater than the preset subcooling degree, for example, the preset subcooling degree may be any temperature in a range from 6° C. to 15° C., and a refrigerant flowing out of the outdoor heat exchanger 103 is all supercooled liquid phase refrigerant. In this case, the refrigerant flowing out of the outdoor heat exchanger 103 is all supercooled liquid phase refrigerant by controlling the opening degree of the outdoor electronic expansion valve 104 and combining it with the a temperature of the refrigerant in the refrigerant pipe between the outdoor heat exchanger 103 and the outdoor electronic expansion valve 104 detected by the first temperature sensor 113.

In some embodiments, in a case where the subcooling degree of the refrigerant flowing out of the outdoor heat exchanger 103 is greater than or equal to the preset subcooling degree, it indicates that the refrigerant flowing through the outdoor heat exchanger 103 may fully release heat and be completely condensed into supercooled liquid phase refrigerant. In this way, the opening degree of the outdoor electronic expansion valve 104 may be adjusted and maintained at the maximum value, which is conducive to increasing the circulation speed of the refrigerant.

In some other examples, in a case where the subcooling degree of the refrigerant flowing out of the outdoor heat exchanger 103 is less than the preset subcooling degree, in order to avoid that the refrigerant flowing through the outdoor heat exchanger 103 is not capable of being fully condensed into liquid refrigerant, the opening degree of the outdoor electronic expansion valve may be adjusted less until the subcooling degree of the refrigerant flowing out of the outdoor heat exchanger 103 is equal to or slightly greater than the preset subcooling degree. That is, a flow speed of the refrigerant may be reduced, so that all the refrigerant flowing out of the outdoor heat exchanger 103 is liquid phase refrigerant.

However, in some embodiments, even if the opening degree of the outdoor electronic expansion valve 104 is adjusted to the minimum, the subcooling degree of the outdoor heat exchanger 103 will still be less than the preset subcooling degree. In this case, the outdoor electronic expansion valve 104 is maintained at the minimum opening degree, the refrigerant flowing from the outdoor heat exchanger 103 to the liquid phase branch pipe 41 is still a gas-liquid two-phase refrigerant. Or, as can be seen from some of the above embodiments, it needs to be ensured that the refrigerant in the unit connecting liquid pipe 106 is the gas-liquid two-phase refrigerant when implementing the refrigerant free addition for air conditioning system 1. In this way, the amount of refrigerant flowing through each indoor heat exchanger 108 is still uneven, thereby resulting in a sharp decrease in the cooling capacity of the part of indoor units 20.

In order to solve the above problem, as shown in FIG. 12A, in some embodiments, the air conditioning system 1 further includes at least one mixing member 50, and the first flow pipe 411 may include at least one mixing member 50. The mixing member 50 has a plurality of first through holes (not shown in FIG. 12A), and the plurality of first through holes are used to be connected to both ends of the first flow pipe 411.

In a case where the air conditioning system 1 operates in the cooling mode, if the refrigerant flowing from the outdoor heat exchanger 103 to the liquid phase branch pipe 41 is the gas-liquid two-phase refrigerant, the gas-liquid two-phase refrigerant may flow from one end of the first flow pipe 411 to the other end of the first flow pipe 411 through the plurality of first through holes in the mixing member 50, and flow into the two second flow pipes 412, respectively, thereby flowing to the first indoor heat exchanger 1081 and the first flow pipe 411 of the next liquid phase branch pipe 41, respectively.

For example, the branch pipe 40 may be a T-shaped structure. For example, referring to FIG. 12A, the first flow pipe 411 of the liquid phase branch pipe 41 may be directly communicated to a second flow pipe 412 along a direction from X to X′ (that is, an axial direction of the first flow pipe 411 is parallel with an axial direction of the second flow pipe 412) and may be communicated to another second flow pipe 412 along a direction from Y to Y′ (that is, the axial direction of the first flow pipe 411 is perpendicular to an axial direction of the other second flow pipe 412). Alternatively, as shown in FIG. 12B, the two second flow pipes 412 may further be communicated in a same direction. That is, an end of the first flow pipe 411 may be vertically communicated between the two second flow pipes 412. Or, as shown in FIG. 13, an end of the first flow pipe 411 is communicated to ends of the two second flow pipes 412, and there is included angles between the first flow pipe 411 and the two second flow pipes 412. In some embodiments, the included angles between the first flow pipe 411 and the two second flow pipes 412 may be the same, for example, the included angle may be 15°.

For example, the liquid phase branch pipe 41 may include three, four, or more second flow pipes 412. For example, in a case where the number of the second flow pipes 412 is three, axes of the three second flow pipes 412 may be coplanar or out of plane. Included angles between axes of any two adjacent second flow pipes 412 may be the same. In addition, the included angles between the axis of the first flow pipe 411 and the axes of the second flow pipes 412 may also be the same.

It will be noted that the number of indoor units 20 in the air conditioning system 1 may be two or more, therefore, when communicating the indoor heat exchanger 108 and the outdoor heat exchanger 103, the number of liquid phase branch pipes 41 may be determined by the number of second flow pipes 412 included in the liquid phase branch pipe 41. For example, in a case where the number of the second flow pipes 412 of the liquid phase branch pipe 41 is two, the number of the liquid phase branch pipe 41 may be one less than the number of the indoor units 20. Or, in a case where the number of the second flow pipes 412 of the liquid phase branch pipe 41 is three, the number of liquid phase branch pipes 41 may be two less than the number of indoor units 20.

In some embodiments, the indoor heat exchanger 108 and the four-way valve 111 may be communicated through the gas phase branch pipe 42. The structure of the gas phase branch pipe 42 is similar to that of the liquid phase branch pipe 41 in the above embodiments. Or, other three-way or multi-way structures may be used to communicate the plurality of indoor heat exchangers 108 and the four-way valve 111.

Therefore, after disposing at least one mixing member 50 in the first flow pipe 411, in a case where the gas-liquid two-phase refrigerant passes through the plurality of first through holes in the mixing member 50, large bubbles formed by the gas phase refrigerant will be cut by the first through holes due to action of inertia and form multiple small bubbles, which is conducive to improving the mixing degree of the gas phase refrigerant into the liquid phase refrigerant, thereby significantly reducing the possibility of the gas-liquid separation phenomenon during the process of the gas-liquid two-phase refrigerant being branched from the first flow pipe 411 to the plurality of second flow pipes 412. Therefore, the amount of refrigerant flowing through the indoor heat exchanger 108 in each indoor unit 20 may be distributed relatively evenly, so that each indoor unit 20 may reach the rated cooling capacity, which ensures that each indoor unit 20 has a good cooling effect and improves the stability of the air conditioning system 1 operating in the cooling condition.

For example, the number of mixing members 50 may be two or more to improve the cutting and crushing effect of the large bubbles in the gas-liquid two-phase refrigerant, thereby improving the mixing degree of the gas-liquid two-phase refrigerant. Alternatively, a mixing member 50 may also be installed in the first flow pipe 411, which improves the mixing degree of the gas-liquid two-phase refrigerant and has a simple structure. In some embodiments, in a case where the first flow pipe 411 includes a plurality of mixing members 50, as shown in FIG. 12B and FIG. 13, the plurality of mixing members 50 may be installed at intervals.

As shown in FIG. 14, in some embodiments, the mixing member 50 includes at least one first mixing piece, and the first mixing piece has a mesh structure with a plurality of second through holes 513 (e.g., referring to FIG. 16). The plurality of second through holes 513 are used to communicate both ends of the first flow pipe 411.

For example, as shown in FIG. 14, the first mixing piece may be a mesh mixing piece 51. FIG. 15 is a structural diagram of the first flow pipe 411 shown in FIG. 14 taken along the line A-A. That is, the at least one mesh mixing piece 51 is disposed in the first flow pipe 411.

FIG. 16 is a partial enlarged view of part D in FIG. 15. In some embodiments, as shown in FIG. 16, the mesh mixing piece 51 may further include a plurality of wires 511 and a first mounting ring 512. The wire 511 may be a metal wire or a wire made of non-metal material with a certain strength. The first mounting ring 512 may be a metal ring or a ring-shaped structure made of a non-metal material with a certain strength. The shape of the first mounting ring 512 may be adapted to the inner wall of the first flow pipe 411. Both ends of the wire 511 may be connected to the inner wall of the first mounting ring 512, and the plurality of wires 511 are interlaced and woven to form a mesh structure with the plurality of second through holes 513. The first mounting ring 512 may be placed in the first flow pipe 411 and connected to the inner wall of the first flow pipe 411, so that the plurality of second through holes 513 may be communicated to both ends of the first flow pipe 411. That is, the gas-liquid two-phase refrigerant may flow from one end of the first flow pipe 411 to the other end of the first flow pipe 411 through the plurality of second through holes 513. For example, the wires 511 forming the second through holes 513 may have a small diameter, which is more conducive to cutting the flowing bubbles and improving the uniformity of the mixing of the gas-liquid two-phase refrigerant.

In some other examples, as shown in FIG. 16, the mesh mixing piece 51 may only include the plurality of wires 511. Both ends of the wire 511 may be connected to the inner wall of the first flow pipe 411, so that the wire 511 is in a tight state. Moreover, the plurality of wires 511 may be interlaced and woven to form a mesh structure with the plurality of second through holes 513. The second through hole 513 is used to communicate the two ends of the first flow pipe 411.

For example, the hole shape of the second through hole 513 may be a square, as shown in FIG. 16; or, the hole shape of the second through hole 513 may be a diamond shape, as shown in FIG. 17; or, the hole shape of the second through hole 513 may be a triangle, as shown in FIG. 18.

For example, as shown in FIG. 14, in the first flow pipe 411, at least one mesh mixing piece 51 may be installed along the direction from X to X′, so that the mesh mixing piece 51 may fill the internal space of the first flow pipe 411 along a radial direction of the first flow pipe 411. In this way, in a case where the gas-liquid two-phase refrigerant flows through the first flow pipe 411, the bubbles of the gas phase refrigerant may be cut by the plurality of wires to form a plurality of small bubbles (approximately the size of the second through hole 513), thereby improving the uniformity of mixing of the gas phase refrigerant and the liquid phase refrigerant.

In some embodiments, in the mesh mixing piece 51, while ensuring the structural strength, the size of the plurality of wires 511 may be as fine as possible, so that the porosity of the mesh mixing piece 51 is approaching 100%, which has a good flow effect when the refrigerant in the first flow pipe 411 flows through the second through holes 513. In the mesh mixing piece 51, a mesh number of the second through holes 513 is a number of second through holes 513 per square inch of the mesh mixing piece 51, which may be referred to as a mesh number n=(24.5/(D1+D2))². D1 is the aperture of the second through hole 513, and D2 represents the diameter of the wire 511. For example, the mesh number of the second through hole 513 in the mesh mixing piece 51 may be in a range from 40 to 635.

For example, in a case where the plurality of mesh mixing pieces 51 are installed in the first flow pipe 411, as shown in FIG. 14, along the direction from X to X′ in the first flow pipe 411, the mesh number of the second through holes 513 in the mesh mixing pieces 51 may be gradually increased. That is, from left to right, the aperture of the second through holes 513 in the mesh mixing piece 51 is gradually decreased. In this way, in a case where the air conditioning system 1 operates in the cooling condition, the bubbles of the gas phase refrigerant flowing through the plurality of mesh mixing pieces 51 from left to right may be cut into less bubbles in sequence, which is conducive to improving the mixing degree of the gas-liquid two-phase refrigerant.

FIG. 19 is a structural diagram of the first flow pipe 411 shown in FIG. 14 taken along the line B-B. In some embodiments, as shown in FIGS. 14 and 19, the mixing member 50 further includes at least one second mixing piece. The second mixing piece includes a first piece body 521. A plurality of third through holes 522 are disposed in the first piece body 521, and the third through holes 522 are used to communicate two ends of the first flow pipe 411.

For example, as shown in FIG. 14, the second mixing piece may be a first orifice plate mixing piece 52.

In some embodiments, as shown in FIG. 19, the first orifice plate mixing piece 52 may further include a second mounting ring 523, and an edge of the first piece body 521 may be connected to an inner wall of the second mounting ring 523. The first orifice plate mixing piece 52 may be installed in the first flow pipe 411 through the second mounting ring 523, and an outer wall of the second mounting ring 523 may be in contact with the inner wall of the first flow pipe 411, so that the first orifice plate mixing piece 52 is connected and installed at a preset position of the first flow pipe 411.

In some embodiments, the first piece body 521 and the second mounting ring 523 may be of a separate structure, or the first piece body 521 and the second mounting ring 523 may be of an integral structure. For example, the edge of the first piece body 521 may be bent along an axial direction of the first flow pipe 411 toward a same side to form a flange structure similar to the second mounting ring 523. And the shape of the flange structure may be adjusted accordingly to adapt to the inner wall of the first flow pipe 411. Alternatively, the first orifice plate mixing piece 52 may further be installed at a preset position of the first flow pipe 411. Or, a clamping groove structure may be disposed on the inner wall of the first flow pipe 411 at the preset position, and the edge of the first piece body 521 is clamped into the clamping groove structure along a radial direction of the first flow pipe 411 to complete the clamping installation of the first orifice plate mixing piece 52. For example, in a case where the first flow pipe 411 and the first piece body 521 are both of metal structure, the first piece body 521 and the inner wall of the first flow pipe 411 may also be directly welded to install the first orifice plate mixing piece 52 at the preset position in the first flow pipe 411.

For example, as shown in FIG. 19, a hole shape of the third through hole 522 of the first orifice plate mixing piece 52 may be hexagonal. Or, the hole shape of the third through hole 522 may also be a circle as shown in FIG. 20.

In some embodiments, in a case where the first orifice plate mixing piece 52 is made of metal material, the plurality of third through holes 522 may be formed by directly punching holes on the first piece body 521. Or, the first piece body 521 with the plurality of third through holes 522 may be directly cast to form. In some other examples, in a case where the first orifice plate mixing piece 52 is made of plastic or other non-metallic materials, an injection molding process may be used to directly produce the first piece body 521 with the plurality of third through holes 522.

In some embodiments, the first orifice plate mixing piece 52 may be provided with 25 to 60 third through holes 522. The plurality of third through holes 522 may be arranged in a matrix on the first piece body 521, or may be arranged in a Z-shaped, a K-shaped, or a 45° or 60° misaligned arrangement, so as to ensure that the first orifice plate mixing piece 52 has a high porosity to reduce the impact of pressure loss on the refrigerant.

FIG. 21 is a structural diagram of the first flow pipe 411 shown in FIG. 14 taken along the line C-C. In some embodiments, as shown in FIGS. 14 and 21, the mixing member 50 further has at least one third mixing piece. The third mixing piece includes a second piece body 531, and the second piece body 531 is provided with a plurality of fourth through holes 532. The plurality of fourth through holes 532 are used to communicate two ends of the first flow pipe 411.

For example, as shown in FIG. 14, the third mixing piece may be a second orifice plate mixing piece 53.

FIG. 22 is a structural diagram of a second orifice plate mixing piece. In some embodiments, the fourth through hole 532 has a coincident cross section with a plane parallel to the second piece body 531. A cross sectional area of the fourth through hole 532 may be gradually decreased from left to right along the direction from X to X′ in FIG. 22 (i.e., the flow direction of refrigerant). With reference to FIG. 14, in a case where the second orifice plate mixing piece 53 is installed in the first flow pipe 411, for example, along the direction from X to X′, the cross sectional area of the fourth through hole 532 on the second orifice plate mixing piece 53 may be gradually decreased. In this case, in a case where the air conditioning system 1 operates in the cooling condition, the pressure of the refrigerant flowing from X to X′ will be gradually increased when passing through the plurality of fourth through holes 532, which is conducive to improving the flow speed of refrigerant passing through the fourth through holes 532.

In some other examples, the second orifice plate mixing piece 53 may further be installed in the first flow pipe 411 in reverse. That is, the second orifice plate mixing piece 53 is installed in the first flow pipe 411 from left to right. In this case, the cross sectional area of the fourth through hole 532 in the second orifice plate mixing piece 53 is gradually increased. Therefore, in a case where the air conditioning system 1 is in the cooling mode, the pressure of the refrigerant flowing from left to right is gradually decreased when passing through the plurality of fourth through holes 532, which is conducive to reducing the flow speed of refrigerant passing through the fourth through holes 532.

For example, the second piece body 531 in the second orifice plate mixing piece 53 has a certain thickness along X to X′ (or the axial direction of the first flow pipe 411). For example, the thickness of the second piece body 531 may be in a range from 0.5 mm to 5 mm. For example, the second piece body 531 with the plurality of fourth through holes 532 may be produced through punching, casting or through-hole injection molding.

In some embodiments, as shown in FIG. 23, the third mixing piece further includes a plurality of sleeves 533. The plurality of sleeves 533 are connected to a same side of the second piece body 531, and a sleeve 533 is aligned with a four through hole 532, so as to communicate two ends of the first flow pipe 411.

For example, along the direction from X to X′ shown in FIG. 23, the plurality of sleeves 533 are connected to the X′ side of the second piece body 531, and a sleeve 533 is aligned with a four through hole 532, so that the fourth through hole 532 may extend in the X′ direction along the axial direction of the second orifice plate mixing piece 53. Alternatively, as shown in FIG. 24, the plurality of sleeves 533 are connected to the X side of the second piece body 531, and a sleeve 533 is aligned with a four through hole 532, so that the fourth through hole 532 may extend in left along the axial direction of the second orifice plate mixing piece 53.

In this case, when the thickness of the second piece body 531 is thin, the length of the fourth through hole 532 in the axial direction is extended by the plurality of sleeves 533. Correspondingly, the sleeve 533 may be provided with a through hole along the direction from X to X′ as an extension structure of the fourth through hole 532. In some embodiments, the cross sectional area of the sleeve 533 may be greater or less than the cross sectional area of the fourth through hole 532, and a sleeve 533 may be smoothly connected to an edge of an inner wall of a fourth through hole 532, so that the cross sectional area of the fourth through hole 532 may be gradually increased or decreased when extending from the second piece body 531 to the sleeve 533. Therefore, the fourth through hole 532 with a longer axial length is beneficial to control the flow of the refrigerant, so as to increase or slow down the flow speed of the refrigerant. Moreover, since there is no need to use a second piece body 531 with a larger thickness, it is further conducive to reducing the mass of the second orifice plate mixing piece 53 and saving manufacturing materials.

For example, the sleeve 533 may be an integral structure with the second piece body 531. For example, the sleeve 533 may be formed by directly punching holes on the second piece body 531 and extending the flange formed after punching. Since no punching waste is formed, the utilization efficiency of the raw material of the second piece body 531 is greatly increased, and the manufacturing method is simple.

In some embodiments, at least two of the mesh mixing piece 51, the first orifice plate mixing piece 52, and the second orifice plate mixing piece 53 may be installed in the first flow pipe 411. In some embodiments, the number of the first orifice plate mixing pieces 52 in the first flow pipe 411 may be one or more. Correspondingly, the number of mesh mixing pieces 51 in the first flow pipe 411 may be one or more.

For example, in a case where at least one mesh mixing piece 51 and at least one first orifice plate mixing piece 52 are installed in the first flow pipe 411, the at least one first orifice plate mixing piece 52 and the at least one mesh mixing piece 51 may be installed in the first flow pipe 411 from left to right in sequence. In some embodiments, the aperture of the second through hole 513 may be greater than the aperture of the third through hole 522, that is, the cross sectional area of the second through hole 513 is greater than the cross sectional area of the third through hole 522. In this case, when the at least one (e.g., one) first orifice plate mixing piece 52 and the at least one mesh mixing piece 51 are installed in the first flow pipe 411 from left to right, the air conditioning system 1 operates in the cooling mode, and the gas-liquid two-phase refrigerant flows through the first flow pipe 411 from left to right, the large bubbles in the gas phase refrigerant may first pass through the second through holes 513, so that the large bubbles are cut into multiple small bubbles with apertures similar to the apertures of the second through holes 513. Then, the small bubbles may pass through the third through holes 522 and be cut by the wires 511 at the edge of the third through holes 522 to form multiple less bubbles (approximately the apertures of the third through holes 522). In this way, the large bubbles in the gas phase refrigerant may be cut for times to form the less bubbles, which is conducive to further improving the mixing degree of the gas phase refrigerant and the liquid phase refrigerant.

For example, as shown in FIG. 14, along the flow direction of the refrigerant (a direction of an arrow shown in FIG. 14, such as the flow direction of the refrigerant in the cooling condition), that is, the direction from X to X′, the second orifice plate mixing piece 53, the first orifice plate mixing piece 52, and the mesh mixing piece 51 may be disposed in the first flow pipe 411 in sequence, so as to facilitate sequential cutting the bubbles formed by the gas phase refrigerant.

For example, as shown in FIG. 25, a second orifice plate mixing piece 53, a first orifice plate mixing piece 52, two mesh mixing pieces 51, and a second orifice plate mixing piece 53 may be disposed at intervals along the direction from X to X′ in the first flow pipe 411. The second orifice plate mixing piece 53 located at the X side may be installed in a forward direction, that is, the cross sectional area (also considered as the aperture) of the fourth through hole 532 is decreased from X to X′ in sequence, which is conducive to improving the flow speed of the refrigerant flowing through the plurality of fourth through holes 532. In addition, the second piece body 531 at the edge of the fourth through holes 532 may cut the large bubbles in the gas phase refrigerant preliminary. In this way, the refrigerant has a fast flow speed when being proximate to the first orifice plate mixing piece 52 by accelerating the refrigerant flowing through the fourth through hole 532 at the X side, that is, the impact force on the first piece body 521 is great, so as to facilitate to cutting the bubbles in the gas phase refrigerant for a second time through the plurality of third through holes 522, so that the mixing degree of the gas-liquid two-phase refrigerant is improved.

Continuing to refer to FIG. 25, since the aperture of the third through hole 522 is large, in order to further cut and separate the bubbles in the gas phase refrigerant, two mesh mixing pieces 51 with gradually increasing mesh numbers (i.e., gradually decreasing apertures) may be installed at the X′ side of the first orifice plate mixing piece 52. Since the cross sectional area of the second through hole 513 of the mesh mixing piece 51 at the X side is large, the plurality of second through holes 513 at the X side may cut and separate the bubbles in the gas phase refrigerant for a third time, so as to separate the bubbles that is cut and separated twice into multiple bubbles that are approximately the size of the second through hole 513. Then, in a case where the refrigerant flows through the plurality of second through holes 513 at the X′ side, since the apertures of the second through holes 513 are further reduced, the bubbles in the liquid phase refrigerant may continue to be cut and separated. In this way, by cutting and separating the gas phase refrigerant four times, the uniformity of the mixing of the gas-liquid two-phase refrigerant is greatly improved, thereby preventing the gas phase refrigerant in the mixed refrigerant from being concentrated and flowing to the indoor heat exchangers 108 of some of the indoor units 20 through the liquid phase branch pipe 41, so that the problem of sharp decline in the cooling capacity of a part of indoor units 20 may be avoided, and each indoor unit 20 has a good cooling effect.

It will be noted that in the first flow pipe 411, since the hole structures of the mixing member 50 through which the refrigerant flows are decreased in sequence, the local pressure will be increased, so that the flow speed of the refrigerant is increased. In order to allow the refrigerant to have a long time to be in contact with the indoor heat exchanger 108 when flowing through the indoor heat exchanger 108, in some embodiments, as shown in FIG. 25, a reversely disposed second orifice plate mixing piece 53 is installed at the X′ side of the two mesh mixing pieces 51, that is, the cross sectional areas (i.e., the aperture) of the corresponding fourth through holes 532 are increased sequentially from X to X′. In this way, in a case where the uniformly mixed refrigerant flows through the plurality of fourth through holes 532 at the X′ side, since the cross sectional areas of the fourth through holes 532 are increased sequentially from X to X′, that is, the fluid pressure is gradually decreased, it is conducive to reducing the flow speed of the refrigerant, so that the refrigerant may stay in the indoor heat exchanger 108 for a long time to fully absorb heat through the indoor heat exchanger 108, thereby improving the cooling effect of the indoor unit 20.

In some other examples, a forwardly disposed second orifice plate mixing piece 53 may be installed at the left end of the first flow pipe 411, and a reversely disposed second orifice plate mixing piece 53 may be installed at the right end of the first flow pipe 411. The corresponding first orifice plate mixing piece 52 and/or the mesh mixing piece 51 may be installed between the two second orifice plate mixing pieces 53. Or, a forwardly disposed second orifice plate mixing piece 53 may be installed at the left end of the first flow pipe 411, and the first orifice plate mixing piece 52 and/or the mesh mixing piece 51 may be installed at the X′ side of the second orifice plate mixing piece 53. Alternatively, a reversely disposed second orifice plate mixing piece 53 may be installed at the right end of the first flow pipe 411, and the first orifice plate mixing piece 52 and/or the mesh mixing piece 51 may be installed at the X side of the second orifice plate mixing piece 53.

Some embodiments of the present disclosure provide a method for controlling the air conditioning system. Referring to FIGS. 1 and 2, the air conditioning system may be the air conditioning system 1 in any of the above embodiments. The air conditioning system 1 includes an outdoor unit 10, an indoor unit 20 and a controller 30. The outdoor unit 10 includes a compressor 102, an outdoor electronic expansion valve 104, and an outdoor heat exchanger 103. The indoor unit 20 includes an indoor electronic expansion valve 107 and an indoor heat exchanger 108. The compressor 102 compresses the refrigerant and discharges a compressed refrigerant, and the outdoor heat exchanger 103 condenses the compressed refrigerant. The outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 adjust the amount of refrigerant condensed by the outdoor heat exchanger 103 in sequence, and the indoor heat exchanger 108 evaporates the refrigerant adjusted by the indoor electronic expansion valve 107. FIG. 26 is a flow diagram of yet another control method of an air conditioning system, in accordance with some embodiments of the present disclosure. As shown in FIG. 26, the method for controlling the air conditioning system includes step 2610 to step 2630.

In step 2610, the opening degree of the indoor electronic expansion valve 107 is obtained.

In step 2620, in a case where a first preset condition is satisfied, the opening degree of the outdoor electronic expansion valve 104 is adjusted according to a relationship between the subcooling degree of the outdoor heat exchanger 103 and a first target subcooling degree interval, and the opening degree of the indoor electronic expansion valve 107 is adjusted according to a relationship between the exhaust superheat degree of the compressor 102 and a target exhaust superheat degree interval.

The first preset condition includes that the opening degree of the indoor electronic expansion valve 107 is lesser than a first preset opening degree.

In step 2630, in a case where the first preset condition is not satisfied, the opening degrees of the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 are adjusted according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval.

In some embodiments, the indoor unit includes a plurality of indoor units, and the method for controlling the air conditioning system further includes that in a case where both the first preset condition and the second preset condition are satisfied, the opening degrees of the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 are adjusted according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval; and in a case where the first preset condition is satisfied and the second preset condition is not satisfied, the opening degree of outdoor electronic expansion valve 104 is adjusted according to the relationship between the subcooling degree of the outdoor heat exchanger 103 and the first target subcooling degree interval, and the opening degree of the indoor electronic expansion valve 107 is adjusted according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval. The second preset condition includes that an opening degree of a target indoor electronic expansion valve in a target indoor unit is greater than or equal to a second preset opening degree, a superheat degree of a target indoor heat exchanger in the target indoor unit is greater than or equal to a target superheat degree, and the exhaust superheat degree of the compressor 102 is greater than or equal to the upper limit of the target exhaust superheat degree interval. The target indoor unit is one of the plurality of indoor units 20. The second preset opening degree is greater than the first preset opening degree.

In some embodiments, the opening degree of outdoor electronic expansion valve 104 is adjusted according to the relationship between the subcooling degree of the outdoor heat exchanger 103 and the first target subcooling degree interval, including that if the subcooling degree of the outdoor heat exchanger 103 is greater than an upper limit of the first target subcooling degree interval, the opening degree of the outdoor electronic expansion valve 104 is increased; if the subcooling degree of the outdoor heat exchanger 103 is less than a lower limit of the first target subcooling degree interval, the opening degree of the outdoor electronic expansion valve 104 is reduced; and if the subcooling degree of the outdoor heat exchanger 103 is greater than or equal to the lower limit of the first target subcooling degree interval, and is less than or equal to the upper limit of the first target subcooling degree interval, the opening degree of the outdoor electronic expansion valve 104 is controlled to remain unchanged.

In some embodiments, the opening degree of the indoor electronic expansion valve 107 is adjusted according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval, including that if the exhaust superheat degree of the compressor 102 is greater than the upper limit of the target exhaust superheat degree interval, the opening degree of the indoor electronic expansion valve 107 is increased; if the exhaust superheat degree of the compressor 102 is less than the lower limit of the target exhaust superheat degree interval, the opening degree of the indoor electronic expansion valve 107 is reduced; and if the exhaust superheat degree of the compressor 102 is greater than or equal to the lower limit of the target exhaust superheat degree interval and less than or equal to the upper limit of the target exhaust superheat degree interval, the opening degree of the indoor electronic expansion valve 107 is controlled to remain unchanged.

In some embodiments, the compressor 102 compresses the refrigerant and discharges the compressed refrigerant, and the indoor heat exchanger 108 condenses the compressed refrigerant. The indoor electronic expansion valve 107 and the outdoor electronic expansion valve 104 adjust the amount of refrigerant condensed by the outdoor heat exchanger 103 in sequence, and the outdoor heat exchanger 103 evaporates the refrigerant adjusted by the outdoor electronic expansion valve 104. The method for controlling the air conditioning system further includes that the opening degree of the outdoor electronic expansion valve 104 is obtained; in a case where a third preset condition is satisfied, the opening degree of the indoor electronic expansion valve 107 is adjusted according to the relationship between the subcooling degree of the indoor heat exchanger 108 and the second target subcooling degree interval, and the opening degree of the outdoor electronic expansion valve 104 is adjusted according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval; and in a case where the third preset condition is not satisfied, the opening degrees of the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 are adjusted according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval. The third preset condition includes that the opening degree of the outdoor electronic expansion valve 104 is less than a third preset opening degree.

In some embodiments, the method for controlling the air conditioning system further includes that in a case where the third preset condition and a fourth preset condition are satisfied, the opening degrees of the outdoor electronic expansion valve 104 and the indoor electronic expansion valve 107 are adjusted according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval; and in a case where the third preset condition is satisfied and the fourth preset condition is not satisfied, the opening degree of the indoor electronic expansion valve 107 is adjusted according to the relationship between the subcooling degree of the indoor heat exchanger 108 and the second target subcooling degree interval, and the opening degree of the outdoor electronic expansion valve 104 is adjusted according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval. The fourth preset condition includes that the opening degree of the outdoor electronic expansion valve 104 is greater than or equal to the fourth preset opening degree, and the exhaust superheat degree of the compressor 102 is greater than or equal to the upper limit of the target exhaust superheat degree interval. The fourth preset opening degree is greater than the third preset opening degree.

In some embodiments, the opening degree of the indoor electronic expansion valve 107 is adjusted according to the relationship between the subcooling degree of the indoor heat exchanger 108 and the second target subcooling degree interval, including that if the subcooling degree of the indoor heat exchanger 108 is greater than the upper limit of the second target subcooling degree interval, the opening degree of the indoor electronic expansion valve 107 is increased; if the subcooling degree of the indoor heat exchanger 108 is less than the lower limit of the second target subcooling degree interval, the opening degree of the indoor electronic expansion valve 107 is reduced; if the subcooling degree of the indoor heat exchanger 108 is greater than or equal to the lower limit of the second target subcooling degree interval, and is less than or equal to the upper limit of the second target subcooling degree interval, the opening degree of the indoor electronic expansion valve 107 is controlled to remain unchanged.

In some embodiments, the opening degree of the outdoor electronic expansion valve 104 is adjusted according to the relationship between the exhaust superheat degree of the compressor 102 and the target exhaust superheat degree interval, including that if the exhaust superheat degree of the compressor 102 is greater than the upper limit of the target exhaust superheat degree interval, the opening degree of the outdoor electronic expansion valve 104 is increased; if the exhaust superheat degree of the compressor 102 is less than the lower limit of the target exhaust superheat degree interval, the opening degree of the outdoor electronic expansion valve 104 is reduced; and if the exhaust superheat degree of the compressor 102 is greater than or equal to the lower limit of the target exhaust superheat degree interval and less than or equal to the upper limit of the target exhaust superheat degree interval, the opening degree of the outdoor electronic expansion valve 104 is controlled to remain unchanged.

The beneficial effects of the method for controlling the above air conditioning system and the beneficial effects of the air conditioning system described in some of the above embodiments are the same, and details will not be repeated herein.

It will be noted that the steps described in a specific order in the drawings of the embodiments of the present disclosure do not require or imply that these steps must be performed in this specific order, or that all steps shown must be performed to achieve the desired results. Each step in the drawings may be appended, some steps may be omitted, a plurality of steps may be combined into one step for execution, or one step may be decomposed into a plurality of steps for execution, etc.

A person skilled in the art will understand that the scope of disclosure in the present application is not limited to specific embodiments discussed above, and may modify and substitute some elements of the embodiments without departing from the spirits of this application. The scope of the application is limited by the appended claims.

Claims

1. An air conditioning system, comprising:

an outdoor unit including a compressor, an outdoor electronic expansion valve, and an outdoor heat exchanger;

an indoor unit including an indoor electronic expansion valve and an indoor heat exchanger; wherein the compressor compresses a refrigerant and discharges the compressed refrigerant, and the outdoor heat exchanger condenses the compressed refrigerant; the outdoor electronic expansion valve and the indoor electronic expansion valve adjust an amount of the refrigerant condensed by the outdoor heat exchanger, and the indoor heat exchanger evaporates the refrigerant adjusted by the indoor electronic expansion valve; and

at least one liquid phase branch pipe, and each liquid phase branch pipe including a first flow pipe and a second flow pipe; an end of the second flow pipe being communicated to an end of the first flow pipe, and another end of the second flow pipe being communicated to the indoor electronic expansion valve; the liquid phase branch pipe being configured to branch or converge a refrigerant flowing through the liquid phase branch pipe;

wherein the first flow pipe includes at least one mixing member, each mixing member has a plurality of first through holes, and the plurality of first through holes are used to communicate two ends of the first flow pipe.

2. The air conditioning system according to claim 1, wherein the mixing member includes:

at least one first mixing piece, and each first mixing piece having a mesh structure; the mesh structure having a plurality of second through holes, and the plurality of second through holes being used to communicate the two ends of the first flow pipe.

3. The air conditioning system according to claim 2, wherein a hole shape of the second through hole is square, diamond, or triangular.

4. The air conditioning system according to claim 2, wherein in the first flow pipe, a mesh number of the second through holes in the at least one first mixing piece is increased along an X to X′ direction.

5. The air conditioning system according to claim 1, wherein the mixing member further includes:

at least one second mixing piece, and each second mixing piece including a first piece body; the first piece body being provided with a plurality of third through holes, and the third through holes being used to communicate the two ends of the first flow pipe;

wherein in the case where the mixing member includes at least one first mixing piece, the at least one second mixing piece is located at a side of the at least one first mixing piece away from the indoor electronic expansion valve.

6. The air conditioning system according to claim 5, wherein the plurality of third through holes are arranged in a matrix, a Z-shaped, a K-shaped, a 45° misaligned arrangement, or a 60° misaligned arrangement.

7. The air conditioning system according to claim 1, wherein the mixing member further includes:

at least one third mixing piece, and each third mixing piece including a second piece body; the second piece body being provided with a plurality of fourth through holes, and the fourth through holes being used to communicate the two ends of the first flow pipe.

8. The air conditioning system according to claim 7, wherein the third mixing piece further includes a plurality of sleeves; the plurality of sleeves are respectively connected to a same side of the second piece body, and a sleeve is aligned with a fourth through hole, so as to communicate the two ends of the first flow pipe.

9. The air conditioning system according to claim 1, further comprising a controller configured to:

obtain an opening degree of the indoor electronic expansion valve;

in a case where a first preset condition is satisfied, adjust an opening degree of the outdoor electronic expansion valve according to a relationship between a subcooling degree of the outdoor heat exchanger and a first target subcooling degree interval, and adjust the opening degree of the indoor electronic expansion valve according to a relationship between an exhaust superheat degree of the compressor and a target exhaust superheat degree interval; and

in a case where the first preset condition is not satisfied, adjust the opening degree of the outdoor electronic expansion valve and the opening degree of the indoor electronic expansion valve according to a relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval;

wherein the first preset condition includes that the opening degree of the indoor electronic expansion valve is less than a first preset opening degree.

10. The air conditioning system according to claim 9, wherein the air conditioning system comprises a plurality of indoor units, and the controller is further configured to:

in a case where the first preset condition and a second preset condition are satisfied, adjust the opening degree of the outdoor electronic expansion valve and the opening degree of the indoor electronic expansion valve according to the relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval;

in a case where the first preset condition is satisfied and the second preset condition is not satisfied, adjust the opening degree of outdoor electronic expansion valve according to a relationship between the subcooling degree of the outdoor heat exchanger and the first target subcooling degree interval, and adjust the opening degree of the indoor electronic expansion valve according to the relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval;

wherein the second preset condition includes that an opening degree of a target indoor electronic expansion valve in a target indoor unit is greater than or equal to a second preset opening degree, a superheat degree of a target indoor heat exchanger in the target indoor unit is greater than or equal to a target superheat degree, and the exhaust superheat degree of the compressor is greater than or equal to an upper limit of the target exhaust superheat degree interval; the target indoor unit is one of the plurality of indoor units; and the second preset opening degree is greater than the first preset opening degree.

11. The air conditioning system according to claim 9, wherein the controller is configured to:

if the subcooling degree of the outdoor heat exchanger is greater than an upper limit of the first target subcooling degree interval, increase the opening degree of the outdoor electronic expansion valve;

if the subcooling degree of the outdoor heat exchanger is less than a lower limit of the first target subcooling degree interval, reduce the opening degree of the outdoor electronic expansion valve; and

if the subcooling degree of the outdoor heat exchanger is greater than or equal to the lower limit of the first target subcooling degree interval, and is less than or equal to the upper limit of the first target subcooling degree interval, control the opening degree of the outdoor electronic expansion valve to remain unchanged.

12. The air conditioning system according to claim 9, wherein the compressor compresses the refrigerant and discharges the compressed refrigerant, and the indoor heat exchanger condenses the compressed refrigerant; the indoor electronic expansion valve and the outdoor electronic expansion valve adjust the amount of refrigerant condensed by the outdoor heat exchanger, and the outdoor heat exchanger evaporates the refrigerant adjusted by the outdoor electronic expansion valve;

the controller further configured to:

obtain the opening degree of the outdoor electronic expansion valve;

in a case where a third preset condition is satisfied, adjust the opening degree of the indoor electronic expansion valve according to a relationship between a subcooling degree of the indoor heat exchanger and a second target subcooling degree interval, and adjust the opening degree of the outdoor electronic expansion valve according to the relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval; and

in a case where the third preset condition is not satisfied, adjust the opening degree of the outdoor electronic expansion valve and the opening degree of the indoor electronic expansion valve according to the relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval;

wherein the third preset condition includes that the opening degree of the outdoor electronic expansion valve is less than a third preset opening degree.

13. The air conditioning system according to claim 12, wherein the controller is further configured to:

in a case where the third preset condition and a fourth preset condition are satisfied, adjust the opening degree of the outdoor electronic expansion valve and the opening degree of the indoor electronic expansion valve according to the relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval;

in a case where the third preset condition is satisfied and the fourth preset condition is not satisfied, adjust the opening degree of the indoor electronic expansion valve according to the relationship between the subcooling degree of the indoor heat exchanger and the second target subcooling degree interval, and adjust the outdoor electronic expansion valve according to the relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval;

wherein the fourth preset condition includes that the opening degree of the outdoor electronic expansion valve is greater than or equal to a fourth preset opening degree, and the exhaust superheat degree of the compressor is greater than or equal to an upper limit of the target exhaust superheat degree interval; and the fourth preset opening degree is greater than the third preset opening degree.

14. The air conditioning system according to claim 12, wherein the controller is configured to:

if the subcooling degree of the indoor heat exchanger is greater than an upper limit of the second target subcooling degree interval, increase the opening degree of the indoor electronic expansion valve;

if the subcooling degree of the indoor heat exchanger is less than a lower limit of the second target subcooling degree interval, reduce the opening degree of the indoor electronic expansion valve; and

if the subcooling degree of the indoor heat exchanger is greater than or equal to the lower limit of the second target subcooling degree interval, and is less than or equal to the upper limit of the second target subcooling degree interval, control the opening degree of the indoor electronic expansion valve to remain unchanged.

15. The air conditioning system according to claim 9, wherein the controller is configured to:

if the exhaust superheat degree of the compressor is greater than an upper limit of the target superheat degree interval, increase an opening degree of at least one of the outdoor electronic expansion valve and the indoor electronic expansion valve;

if the exhaust superheat degree of the compressor is less than a lower limit of the target superheat degree interval, reduce the opening degree of the at least one of the outdoor electronic expansion valve and the indoor electronic expansion valve; and

if the exhaust superheat degree of the compressor is greater than or equal to the upper limit of the target superheat degree interval and less than or equal to the lower limit of the target superheat degree interval, control an opening degree of at least one of the outdoor electronic expansion valve and a plurality of indoor electronic expansion valves to remain unchanged.

16. A method for controlling an air conditioning system, wherein the air conditioning system includes an outdoor unit, an indoor unit, and a controller; the outdoor unit includes a compressor, an outdoor electronic expansion valve, and an outdoor heat exchanger; the indoor unit includes an indoor electronic expansion valve and an indoor heat exchanger; the compressor compresses a refrigerant and discharges the compressed refrigerant, and the outdoor heat exchanger condenses the compressed refrigerant; and the outdoor electronic expansion valve and the indoor electronic expansion valve adjust amount of the refrigerant condensed by the outdoor heat exchanger, and the indoor heat exchanger evaporates the refrigerant adjusted by the indoor electronic expansion valve;

the method comprises:

obtaining an opening degree of the indoor electronic expansion valve;

in a case where a first preset condition is satisfied, adjusting an opening degree of the outdoor electronic expansion valve according to a relationship between a subcooling degree of the outdoor heat exchanger and a first target subcooling degree interval, and adjusting the opening degree of the indoor electronic expansion valve according to a relationship between an exhaust superheat degree of the compressor and a target exhaust superheat degree interval;

in a case where the first preset condition is not satisfied, adjusting the opening degree of the outdoor electronic expansion valve and the opening degree of the indoor electronic expansion valve according to a relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval;

wherein the first preset condition includes that the opening degree of the indoor electronic expansion valve is less than a first preset opening degree.

17. The method according to claim 16, wherein the indoor unit includes a plurality of indoor units, and the method comprises:

in a case where the first preset condition and a second preset condition are satisfied, adjusting the opening degree of the outdoor electronic expansion valve and the opening degree of the indoor electronic expansion valve according to the relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval;

in a case where the first preset condition is satisfied and the second preset condition is not satisfied, adjusting the opening degree of outdoor electronic expansion valve according to a relationship between the subcooling degree of the outdoor heat exchanger and the first target subcooling degree interval, and adjusting the opening degree of the indoor electronic expansion valve according to the relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval;

wherein the second preset condition includes that an opening degree of a target indoor electronic expansion valve in a target indoor unit is greater than or equal to a second preset opening degree, a superheat degree of a target indoor heat exchanger in the target indoor unit is greater than or equal to a target superheat degree, and the exhaust superheat degree of the compressor is greater than or equal to an upper limit of the target exhaust superheat degree interval; the target indoor unit is one of the plurality of indoor units; and the second preset opening degree is greater than the first preset opening degree.

18. The method according to claim 16, wherein the adjusting the opening degree of outdoor electronic expansion valve according to a relationship between the subcooling degree of the outdoor heat exchanger and the first target subcooling degree interval, includes:

if the subcooling degree of the outdoor heat exchanger is greater than an upper limit of the first target subcooling degree interval, increasing the opening degree of the outdoor electronic expansion valve;

if the subcooling degree of the outdoor heat exchanger is less than a lower limit of the first target subcooling degree interval, reducing the opening degree of the outdoor electronic expansion valve; and

if the subcooling degree of the outdoor heat exchanger is greater than or equal to the lower limit of the first target subcooling degree interval, and is less than or equal to the upper limit of the first target subcooling degree interval, controlling the opening degree of the outdoor electronic expansion valve to remain unchanged.

19. The method according to claim 16, wherein the adjusting the opening degree of the indoor electronic expansion valve according to the relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval, includes:

if the exhaust superheat degree of the compressor is greater than an upper limit of the target superheat degree interval, increasing the opening degree of the indoor electronic expansion valve;

if the exhaust superheat degree of the compressor is less than a lower limit of the target superheat degree interval, reducing the opening degree of the indoor electronic expansion valve; and

if the exhaust superheat degree of the compressor is greater than or equal to the upper limit of the target superheat degree interval and less than or equal to the lower limit of the target superheat degree interval, controlling the opening degree of the indoor electronic expansion valve to remain unchanged.

20. The method according to claim 16, wherein the compressor compresses the refrigerant and discharges the compressed refrigerant, and the indoor heat exchanger condenses the compressed refrigerant; the indoor electronic expansion valve and the outdoor electronic expansion valve adjust the amount of refrigerant condensed by the outdoor heat exchanger, and the outdoor heat exchanger evaporates the refrigerant adjusted by the outdoor electronic expansion valve; the method further comprises:

obtaining the opening degree of the outdoor electronic expansion valve;

in a case where a third preset condition is satisfied, adjusting the opening degree of the indoor electronic expansion valve according to a relationship between the subcooling degree of the indoor heat exchanger and the second target subcooling degree interval, and adjusting the opening degree of the outdoor electronic expansion valve according to the relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval;

in a case where the third preset condition is not satisfied, adjusting the opening degree of the outdoor electronic expansion valve and the opening degree of the indoor electronic expansion valve according to the relationship between the exhaust superheat degree of the compressor and the target exhaust superheat degree interval; and

wherein the third preset condition includes that the opening degree of the outdoor electronic expansion valve is less than a third preset opening degree.