Air conditioning system and control method thereof

Abstract

The application relates to an air conditioning system and a control method thereof, wherein the air conditioning system comprises: a refrigerant circulation loop; a liquid storage container for storing refrigerant and provided with an inlet and an outlet; an inlet pipeline provided with an inlet valve, a first end of the inlet pipeline being communicated with the inlet, and a second end of the inlet pipeline being communicated with at least one of a low-pressure side pipeline, a medium-pressure side pipeline and a high-pressure side pipeline; and a discharge pipeline provided with a discharge valve, a first end of the discharge pipeline being communicated with the outlet, and a second end of the discharge pipeline being communicated with at least one of the low-pressure side pipeline, the medium-pressure side pipeline and the high-pressure side pipeline; wherein when the inlet valve is in an open state, the pressure at the first end of the inlet pipeline is less than that at the second end, so that the refrigerant is stored into the liquid storage container by using the pressure difference; and when the discharge valve is in the open state, the pressure at the first end of the discharge pipeline is greater than that at the second end, so that the refrigerant in the liquid storage container is discharged by using the pressure difference.

Description

TECHNICAL FIELD

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

[0002] A multi-connected air conditioning system is a system in which one outdoor unit is connected to multiple indoor units. The refrigeration system of the multi-connected air conditioning system can deliver refrigerant liquid to multiple indoor units through pipelines. By controlling the refrigerant circulation amount of the compressor and the refrigerant flow into each heat exchanger of the indoor units, the indoor cooling and heating load requirements can be met in a timely manner.

[0003] The current multi-connected air conditioning system can only realize the conventional refrigeration mode and heating mode, and the heat exchange effect is poor. SUMMARY

[0004] Some embodiments of the present disclosure provide an air conditioning system and a control method thereof, which can make the air conditioning system have a better heat exchange effect.

[0005] The first aspect of the present disclosure provides an air conditioning system, comprising:

[0006] a refrigerant circulation loop, which is provided with a compressor, an evaporator and a condenser, a high-pressure side pipeline between the discharge port of the compressor and the condenser, a medium-pressure side pipeline between the condenser and the evaporator, and a low-pressure side pipeline between the evaporator and the suction port of the compressor;

[0007] a liquid storage container for storing refrigerant and having an inlet and an outlet;

[0008] a liquid inlet pipeline provided with a liquid inlet valve having an on state and an off state, a first end of the liquid inlet pipeline being in communication with the inlet, and a second end of the liquid inlet pipeline being in communication with at least one of the low-pressure side pipeline, the medium-pressure side pipeline and the high-pressure side pipeline; and

[0009] a liquid outlet pipeline provided with a liquid outlet valve having an on state and an off state, a first end of the liquid outlet pipeline being in communication with the outlet, and a second end of the liquid outlet pipeline being in communication with at least one of the low-pressure side pipeline, the medium-pressure side pipeline and the high-pressure side pipeline;

[0010] In the case where the liquid inlet valve is in the on state, the pressure at the first end of the liquid inlet pipeline is less than the pressure at the second end, so as to store the refrigerant in the refrigerant circulation loop into the liquid storage container by using the pressure difference; in the case where the liquid outlet valve is in the on state, the pressure at the first end of the liquid outlet pipeline is greater than the pressure at the second end, so as to discharge the refrigerant in the liquid storage container to the refrigerant circulation loop by using the pressure difference.

[0011] In some embodiments, the liquid storage container further has a pressure regulating port, and the air conditioning system further comprises:

[0012] The pressure relief branch is provided with a balance valve having an on state and an off state, a first end of the pressure relief branch is communicated with the pressure regulating port;

[0013] In the case that the balance valve is in the on state, the pressure in the liquid storage container is released through the pressure relief branch.

[0014] In some embodiments, the liquid storage container further has a pressure regulating port, and the air conditioning system further comprises:

[0015] The pressure relief branch is provided with a balance valve having an on state and an off state, a first end of the pressure relief branch is communicated with the pressure regulating port;

[0016] In the case that the balance valve is in the on state, the pressure in the liquid storage container is released through the pressure relief branch.

[0017] In some embodiments, the liquid inlet pipeline comprises a first liquid inlet branch, a second end of the first liquid inlet branch is communicated with the medium-pressure side pipeline, and the liquid inlet valve comprises a first liquid inlet valve arranged on the first liquid inlet branch; and

[0018] The liquid outlet pipeline comprises a first liquid outlet branch, a second end of the first liquid outlet branch is configured to be communicated with the low-pressure side pipeline in the cooling mode and with the high-pressure side pipeline in the heating mode, and the liquid outlet valve comprises a first liquid outlet valve arranged on the first liquid outlet branch.

[0019] In some embodiments, the refrigerant circulation loop further comprises a four-way reversing valve and a gas-liquid separator, the four-way reversing valve is used for reversing when switching between the cooling mode and the heating mode, and the gas-liquid separator is arranged on a pipeline between the four-way reversing valve and the suction port of the compressor;

[0020] In the case that the balance valve is in the on state, the pressure in the liquid storage container is released through the pressure relief branch.

[0021] In some embodiments, the liquid inlet port and the pressure regulating port are arranged in an upper region of the liquid storage container, and the liquid outlet port is arranged in a lower region of the liquid storage container.

[0022] In some embodiments,

[0023] The liquid inlet pipeline comprises a second liquid inlet branch, a second end of the second liquid inlet branch is communicated with the low-pressure side pipeline, and the liquid inlet valve further comprises a second liquid inlet valve arranged on the second liquid inlet branch; and / or

[0024] The liquid outlet pipeline comprises a second liquid outlet branch, a second end of the second liquid outlet branch is communicated with the medium-pressure side pipeline, and the liquid outlet valve further comprises a second liquid outlet valve arranged on the second liquid outlet branch.

[0025] In some embodiments, the refrigerant circulation loop further comprises a four-way reversing valve for reversing when switching between the cooling mode and the heating mode, and a gas-liquid separator arranged on the pipeline between the four-way reversing valve and the suction port of the compressor;

[0026] The second end of the second liquid inlet branch is connected between the inlet of the four-way reversing valve and the gas-liquid separator.

[0027] In some embodiments, a total pipeline section is formed between the four-way reversing valve and the second end of the second liquid inlet branch, a branch pipeline section is formed between the second end of the second liquid inlet branch and the inlet of the gas-liquid separator, and the total pipeline section communicates with both the second liquid inlet branch and the branch pipeline section.

[0028] The refrigerant flow resistance of the branch pipeline section is greater than the refrigerant flow resistance of the second liquid inlet branch.

[0029] In some embodiments, the height of the second liquid inlet branch is lower than the length of the section of the branch pipeline section close to the second end of the second liquid inlet branch; and / or

[0030] The branch pipeline section is provided with a resistance increasing part configured to increase the refrigerant flow resistance of the branch pipeline section.

[0031] In some embodiments, the liquid inlet pipeline comprises a second liquid inlet branch and a pressurized branch, the second end of the second liquid inlet branch communicates with the low-pressure side pipeline, and the liquid inlet valve comprises a second liquid inlet valve arranged on the second liquid inlet branch; the pressurized branch is provided with a pressurized valve having an on state and an off state, the first end of the pressurized branch communicates with the pressure regulating port of the liquid storage container, and the second end of the pressurized branch communicates with the high-pressure side pipeline.

[0032] The liquid discharge pipeline comprises a first liquid discharge branch and a second liquid discharge branch, the second end of the first liquid discharge branch is configured to communicate with the low-pressure side pipeline in the cooling mode and with the high-pressure side pipeline in the heating mode; the second end of the second liquid discharge branch communicates with the medium-pressure side pipeline; the liquid discharge valve comprises a first liquid discharge valve arranged on the first liquid discharge branch and a second liquid discharge valve arranged on the second liquid discharge branch.

[0033] The refrigerant circulation loop is provided with a second control valve on the pipeline section between the second end of the second liquid inlet branch and the suction port of the compressor; the liquid storage container has a gas outlet, and the air conditioning system further comprises a first control valve, the first end of the first control valve communicates with the gas outlet, and the second end of the first control valve is connected to the pipeline section between the second control valve and the suction port of the compressor.

[0034] The second aspect of the present disclosure provides a control method based on the above-mentioned embodiments of the air conditioning system, comprising:

[0035] Liquid collection mode: the liquid inlet valve is in the on state, and the pressure at the first end of the liquid inlet pipeline is less than the pressure at the second end, so that the refrigerant in the refrigerant circulation loop is stored in the liquid storage container;

[0036] Liquid discharge mode: when it is necessary to discharge the refrigerant in the liquid storage container to the refrigerant circulation loop, the liquid discharge valve is in the on state, and the pressure at the first end of the liquid discharge pipeline is greater than the pressure at the second end.

[0037] In some embodiments, the air conditioning system further comprises a pressure relief branch and a pressurization branch, the pressure relief branch is provided with a balance valve, the first end of the pressure relief branch is in communication with the pressure regulating port of the liquid storage container; the pressurization branch is provided with a pressurization valve, the first end of the pressurization branch is in communication with the pressure regulating port, and the second end of the pressurization branch is in communication with the high-pressure side pipeline;

[0038] The liquid inlet pipeline comprises a first liquid inlet branch, the second end of the first liquid inlet branch is in communication with the medium-pressure side pipeline, and the liquid inlet valve comprises a first liquid inlet valve arranged on the first liquid inlet branch;

[0039] The liquid collection mode comprises a refrigeration liquid collection mode and a heating liquid collection mode, in the refrigeration liquid collection mode and the heating liquid collection mode, the liquid discharge valve and the pressurization valve are both in the off state, the first liquid inlet valve is in the on state, and the balance valve is in the on state when the pressure difference between the two ends of the first liquid inlet valve is less than a preset threshold, so as to release the pressure in the liquid storage container.

[0040] In some embodiments, the liquid discharge pipeline comprises a first liquid discharge branch, the second end of the first liquid discharge branch is configured to be in communication with the low-pressure side pipeline in the refrigeration mode and in communication with the high-pressure side pipeline in the heating mode, the liquid discharge valve comprises a first liquid discharge valve arranged on the first liquid discharge branch; the liquid discharge mode further comprises a refrigeration liquid discharge mode and a heating liquid discharge mode,

[0041] In the refrigeration liquid discharge mode, the first liquid discharge valve is in the on state, and the first liquid inlet valve and the balance valve are both in the off state;

[0042] In the heating liquid discharge mode, first, the first liquid inlet valve is in the on state, and when the pressure in the liquid storage container reaches the pressure at the second end of the first liquid inlet branch, the first liquid inlet valve is in the off state; then, the compressor is reduced in frequency or stopped, and at this time, the first liquid discharge valve is in the on state.

[0043] In some embodiments, the air conditioning system further comprises a pressurization branch provided with a pressurization valve, the first end of the pressurization branch is in communication with the pressure regulating port, and the second end of the pressurization branch is in communication with the high-pressure side pipeline; the liquid discharge pipeline comprises a first liquid discharge branch, the second end of the first liquid discharge branch is configured to be in communication with the low-pressure side pipeline in the refrigeration mode and in communication with the high-pressure side pipeline in the heating mode, and the liquid discharge valve comprises a first liquid discharge valve arranged on the first liquid discharge branch;

[0044] The liquid discharge modes include: a first refrigeration liquid discharge mode, a second refrigeration liquid discharge mode, a first heating liquid discharge mode, and a second heating liquid discharge mode; wherein

[0045] In the first refrigeration liquid discharge mode, the first liquid discharge valve is in the on state, the pressurizing valve is in the on state when the internal pressure of the liquid storage container drops to the pressure of the low-pressure side pipeline, and the first liquid inlet valve and the balance valve are both in the off state;

[0046] In the second refrigeration liquid discharge mode, the balance valve is in the on state, and the first liquid inlet valve, the first liquid discharge valve, and the pressurizing valve are all in the off state;

[0047] In the first heating liquid discharge mode, the pressurizing valve is in the on state to raise the internal pressure of the liquid storage container to the pressure of the second end of the pressurizing branch, and the first liquid discharge valve is in the on state;

[0048] In the second heating liquid discharge mode, the pressurizing valve is first in the on state, and then switches to the off state when the internal pressure of the liquid storage container rises to the pressure of the second end of the pressurizing branch; then, the compressor is reduced in frequency or stopped, and at this time, the first liquid discharge valve is in the on state.

[0049] In some embodiments, the liquid inlet pipeline includes a second liquid inlet branch, the second end of the second liquid inlet branch communicates with the low-pressure side pipeline, and the liquid inlet valve further includes a second liquid inlet valve arranged on the second liquid inlet branch; the liquid discharge pipeline includes a second liquid discharge branch, the second end of the second liquid discharge branch communicates with the medium-pressure side pipeline, and the liquid discharge valve further includes a second liquid discharge valve arranged on the second liquid discharge branch; a branch pipeline section is formed between the second end of the second liquid inlet branch and the inlet of the gas-liquid separator;

[0050] The liquid collection modes further include: a refrigeration low-pressure side liquid collection mode and a heating low-pressure side liquid collection mode, in which the second liquid inlet valve is in the on state, and the balance valve is opened when the pressure in the liquid storage container rises to a condition that the refrigerant flow resistance of the second liquid inlet branch is greater than the branch pipeline section; and / or

[0051] The liquid discharge modes further include: a refrigeration medium-pressure side liquid discharge mode, in which the pressurizing valve is first in the on state, and then switches to the off state when the pressure in the liquid storage container rises to the pressure of the second end of the pressurizing branch; then, the second liquid discharge valve is opened.

[0052] In some embodiments, the liquid inlet pipeline includes a second liquid inlet branch and a pressurizing branch, the second end of the second liquid inlet branch communicates with the low-pressure side pipeline, and the liquid inlet valve includes a second liquid inlet valve arranged on the second liquid inlet branch; the pressurizing branch is provided with a pressurizing valve, the first end of the pressurizing branch communicates with the pressure regulating port of the liquid storage container, and the second end of the pressurizing branch communicates with the high-pressure side pipeline;

[0053] The drain pipeline comprises a first drain branch and a second drain branch, a second end of the first drain branch is configured to communicate with the low-pressure side pipeline in the cooling mode and communicate with the high-pressure side pipeline in the heating mode; a second end of the second drain branch communicates with the medium-pressure side pipeline; the drain valve comprises a first drain valve arranged on the first drain branch and a second drain valve arranged on the second drain branch;

[0054] The refrigerant circulation loop is provided with a second control valve on a pipeline section between the second end of the second liquid inlet branch and the suction port of the compressor; the liquid storage container has an exhaust port, and the air conditioning system further comprises a first control valve, a first end of the first control valve communicates with the exhaust port, and a second end of the first control valve is connected to the pipeline section between the second control valve and the suction port of the compressor;

[0055] The liquid collection mode comprises a cooling low-pressure side liquid collection mode and a heating low-pressure side liquid collection mode, in which the second liquid inlet valve and the first control valve are in the on state.

[0056] In some embodiments, the drain mode comprises a cooling medium-pressure side drain mode and a heating high-pressure side drain mode,

[0057] In the cooling medium-pressure side drain mode, the first control valve is in the off state, and the second control valve is in the on state, then the pressurizing valve is in the on state to increase the pressure in the liquid storage container, and the second drain valve is in the on state;

[0058] In the heating high-pressure side drain mode, the first control valve is in the off state, and the second control valve is in the on state, then the pressurizing valve is in the on state to increase the pressure in the liquid storage container, and the first drain valve is in the on state.

[0059] Based on the above technical solutions, the present disclosure has at least the following beneficial effects:

[0060] The air conditioning system of the embodiment of the present disclosure is additionally provided with a liquid storage container, and is connected to at least one of the low-pressure side pipeline, the medium-pressure side pipeline and the high-pressure side pipeline in the system through the liquid inlet valve and the drain valve which can realize the on-off function, on the basis of realizing the conventional refrigerant mode and the heating mode, the excess refrigerant in the refrigerant circulation loop can be collected from a specific pressure side according to the actual heat exchange demand of the air conditioning system by using the pressure difference, or the refrigerant in the liquid storage container can be discharged into the refrigerant circulation loop according to the actual refrigerant demand to supplement the refrigerant, so as to achieve the best heat exchange effect and improve the system heat exchange efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0061] The accompanying drawings, which are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this application, illustrate exemplary embodiments of the present disclosure and together with the description serve to explain the present disclosure. In the drawings:

[0062] Figure 1 Schematic diagram of the first embodiment of the air conditioning system of the present disclosure in a regular cooling mode;

[0063] Figure 2 Schematic diagram of the first embodiment of the air conditioning system of the present disclosure in a regular heating mode;

[0064] Figure 3 Schematic diagram of the first embodiment of the air conditioning system of the present disclosure in a cooling collection mode;

[0065] Figure 4 Schematic diagram of the first embodiment of the air conditioning system of the present disclosure in a first cooling drainage mode;

[0066] Figure 5 Schematic diagram of the first embodiment of the air conditioning system of the present disclosure in a second cooling drainage mode;

[0067] Figure 6 Schematic diagram of the first embodiment of the air conditioning system of the present disclosure in a heating collection mode;

[0068] Figure 7 Schematic diagram of the first embodiment of the air conditioning system of the present disclosure in a first heating drainage mode;

[0069] Figure 8 Schematic diagram of the first embodiment of the air conditioning system of the present disclosure in a second heating drainage mode, with the pressurizing valve being opened first;

[0070] Figure 9 Schematic diagram of the first embodiment of the air conditioning system of the present disclosure in a second heating drainage mode, with the first drainage valve being opened later;

[0071] Figure 10 Schematic diagram of the second embodiment of the air conditioning system of the present disclosure in a regular cooling mode;

[0072] Figure 11 Schematic diagram of the second embodiment of the air conditioning system of the present disclosure in a regular heating mode;

[0073] Figure 12 Schematic diagram of the second embodiment of the air conditioning system of the present disclosure in a cooling collection mode;

[0074] Figure 13 Schematic diagram of the second embodiment of the air conditioning system of the present disclosure in a cooling drainage mode;

[0075] Figure 14This is a schematic diagram of the second embodiment of the air conditioning system of this disclosure in heating and liquid collection mode;

[0076] Figure 15 The schematic diagram shows the first liquid inlet valve being opened when the second embodiment of the air conditioning system of this disclosure is in heating and liquid draining mode.

[0077] Figure 16 This is a schematic diagram showing the opening of the first drain valve when the second embodiment of the air conditioning system is in heating and draining mode.

[0078] Figure 17 This is a schematic diagram of the third embodiment of the air conditioning system of this disclosure in conventional cooling mode;

[0079] Figure 18 This is a schematic diagram of the third embodiment of the air conditioning system of this disclosure in conventional heating mode;

[0080] Figure 19 This is a schematic diagram of the third embodiment of the air conditioning system of this disclosure in the liquid collection mode on the low-pressure side of the refrigeration side;

[0081] Figure 20 This is a schematic diagram of the third embodiment of the air conditioning system of this disclosure in the medium-pressure side liquid discharge mode of refrigeration.

[0082] Figure 21 This is a schematic diagram of the third embodiment of the air conditioning system of this disclosure in heating and liquid collection mode;

[0083] Figure 22 for Figure 21 Enlarged view of point A in the image;

[0084] Figure 23 for Figure 22 A schematic diagram of a variant example;

[0085] Figure 24 for Figure 22 A schematic diagram of another variation;

[0086] Figure 25 This is a schematic diagram of the third embodiment of the air conditioning system of this disclosure in heating and draining mode;

[0087] Figure 26 This is a schematic diagram of the fourth embodiment of the air conditioning system of this disclosure in conventional cooling mode;

[0088] Figure 27 This is a schematic diagram of the fourth embodiment of the air conditioning system of this disclosure in conventional heating mode;

[0089] Figure 28 This is a schematic diagram of the fourth embodiment of the air conditioning system of this disclosure in the liquid collection mode on the low-pressure side of the refrigeration side;

[0090] Figure 29 schematic diagram of a fourth embodiment of the air conditioning system of the present disclosure in a heating high-pressure side drain mode;

[0091] Figure 30 schematic diagram of a fourth embodiment of the air conditioning system of the present disclosure in a heating low-pressure side drain mode;

[0092] Figure 31 schematic diagram of a fourth embodiment of the air conditioning system of the present disclosure in a heating high-pressure side drain mode;

[0093] Figure 32 schematic diagram of a fourth embodiment of the air conditioning system of the present disclosure in a heating high-pressure side drain mode;

[0094] Figure 33 schematic diagram of a fourth embodiment of the air conditioning system of the present disclosure in a heating high-pressure side drain mode;

[0095] Figure 34 schematic diagram of a fourth embodiment of the air conditioning system of the present disclosure in a heating high-pressure side drain mode;

[0096] Figure 35 schematic diagram of a fourth embodiment of the air conditioning system of the present disclosure in a heating high-pressure side drain mode;

[0097] Figure 36 schematic diagram of a fourth embodiment of the air conditioning system of the present disclosure in a heating high-pressure side drain mode;

[0098] Figure 37 schematic diagram of a fourth embodiment of the air conditioning system of the present disclosure in a heating high-pressure side drain mode.

[0099] It should be understood that the dimensions of the various parts shown in the drawings are not drawn to scale. In addition, the same or similar reference numerals are used to represent the same or similar components.

[0100] BRIEF DESCRIPTION OF DRAWINGS

[0101] 101, compressor; 102, first pressure sensor; 103, four-way reversing valve; 104, outdoor heat exchanger; 105, outdoor unit throttling element; 106, liquid pipe valve; 107, gas pipe valve; 108, second pressure sensor; 109, gas-liquid separator; 110, liquid storage container; 111, pressure valve; 112, balance valve; 113, first liquid inlet valve; 114, unloading valve; 115, first liquid drain valve; 116, first check valve; 117, second liquid drain valve; 118, second check valve; 119, second liquid inlet valve; 120, first control valve; 121, second control valve; 122, indoor heat exchanger;

[0102] 1, first liquid inlet branch; 2, first liquid outlet branch; 3, pressure relief branch; 4, pressure increase branch; 5, second liquid inlet branch; 6, second liquid outlet branch; 10, resistance increasing part.

[0103] A, liquid inlet; B, liquid outlet; C, pressure regulating port; D, gas outlet; a, main pipeline section; b, first branch pipeline section; c, second branch pipeline section. DETAILED DESCRIPTION

[0104] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative in nature and is in no way intended to limit the disclosure, its application or uses, except as described by the appended claims. The present disclosure can be implemented in numerous different forms, as is not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the present disclosure to those skilled in the art. It should be noted that the relative arrangement of the components and steps set forth in these embodiments, the components of the materials, numerical expressions, and numerical values, unless specifically stated otherwise, should be interpreted as merely illustrative, and not as a limitation.

[0105] The "first", "second", and similar words used in the present disclosure do not indicate any order, number, or importance, but are only used to distinguish different parts. "Include" or "contain" and similar words mean that the elements before the word cover the elements listed after the word, and do not exclude the possibility of also covering other elements. "Up", "down", "left", "right", and the like are only used to indicate relative positional relationships, which may also change accordingly when the absolute position of the described object changes.

[0106] In the present disclosure, when it is described that a particular device is located between a first device and a second device, there can be an intervening device between the particular device and the first device or the second device, or there can be no intervening device. When it is described that a particular device is connected to other devices, the particular device can be directly connected to the other devices without an intervening device, or it can not be directly connected to the other devices with an intervening device.

[0107] All terms used in the present disclosure, including technical terms or scientific terms, have the same meaning as understood by a person of ordinary skill in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary should be interpreted in a manner consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or excessively formalized sense, unless otherwise explicitly defined herein.

[0108] Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but where appropriate, the techniques, methods, and devices should be considered as part of the specification.

[0109] Based on the above-mentioned embodiments of the present disclosure, the technical features of one of the embodiments can be beneficially combined with one or more of the other embodiments without explicit negation or conflict.

[0110] The present disclosure provides an air conditioning system, such as Figures 1 to 37 As shown, five different types of embodiments are illustrated. In some embodiments, the air conditioning system comprises:

[0111] A refrigerant circulation loop, on which a compressor 101, an evaporator and a condenser are arranged, a high-pressure side pipeline between the exhaust port of the compressor 101 and the condenser, a medium-pressure side pipeline between the condenser and the evaporator, and a low-pressure side pipeline between the evaporator and the suction port of the compressor 101;

[0112] A liquid storage container 110 for storing refrigerant and having a liquid inlet A and a liquid outlet B;

[0113] A liquid inlet pipeline, on which a liquid inlet valve with an on state and an off state is arranged, a first end of the liquid inlet pipeline being in communication with the liquid inlet A, and a second end of the liquid inlet pipeline being in communication with at least one of the low-pressure side pipeline, the medium-pressure side pipeline and the high-pressure side pipeline; and

[0114] A liquid outlet pipeline, on which a liquid outlet valve with an on state and an off state is arranged, a first end of the liquid outlet pipeline being in communication with the liquid outlet B, and a second end of the liquid outlet pipeline being in communication with at least one of the low-pressure side pipeline, the medium-pressure side pipeline and the high-pressure side pipeline;

[0115] Wherein, when the liquid inlet valve is in the on state, the pressure at the first end of the liquid inlet pipeline is less than the pressure at the second end, so as to store the refrigerant in the refrigerant circulation loop into the liquid storage container 110 by using the pressure difference; when the liquid outlet valve is in the on state, the pressure at the first end of the liquid outlet pipeline is greater than the pressure at the second end, so as to discharge the refrigerant in the liquid storage container 110 to the refrigerant circulation loop by using the pressure difference.

[0116] Specifically, the refrigerant circulation loop is provided with a compressor 101, an evaporator and a condenser, as shown in Figure 1 As shown, from the perspective of the arrangement position, the refrigerant circulation loop comprises the compressor 101, an outdoor heat exchanger 104 and an indoor heat exchanger 122, and the indoor heat exchanger 122 is only in Figure 1The number thereof can be one or more, and the indoor heat exchanger 122 is omitted in other figures. In the refrigeration state, the indoor heat exchanger 122 acts as an evaporator, and the outdoor heat exchanger 104 acts as a condenser. An outdoor unit throttling element 105 can be further arranged at a position downstream of the outlet of the outdoor heat exchanger 104, for throttling and cooling the refrigerant. In the heating state, the indoor heat exchanger 122 acts as a condenser, and the outdoor heat exchanger 104 acts as an evaporator. The refrigeration state and the heating state are switched by the four-way valve 103. The liquid storage container 110 can be a liquid storage tank or the like, for temporarily storing the refrigerant in the refrigerant circulation loop. For example, the outdoor unit system can be a multi-split outdoor unit.

[0117] For example, the liquid storage container 110 can be arranged in the outdoor unit system, or can also be arranged between the indoor unit system and the outdoor unit system.

[0118] For example, the refrigerant circulation loop further comprises a four-way valve 103 for switching between the refrigeration mode and the heating mode, and a gas-liquid separator 109 arranged on the pipeline between the four-way valve 103 and the suction port of the compressor 101.

[0119] For such a system, as shown in FIG. 1, Figure 1 in the refrigeration mode, the high-pressure side pipeline is the pipeline between the discharge port of the compressor 101 and the condenser (outdoor heat exchanger 104), the medium-pressure side pipeline is the pipeline between the condenser (outdoor heat exchanger 104) and the evaporator (indoor heat exchanger), and the low-pressure side pipeline includes the pipeline from the evaporator (indoor heat exchanger) to the inlet of the four-way valve 103, and the pipeline between the outlet of the gas-liquid separator 109 and the suction port of the compressor 101.

[0120] As shown in FIG. 2, Figure 2 in the heating mode, the high-pressure side pipeline is the pipeline between the discharge port of the compressor 101 and the condenser (indoor heat exchanger), the medium-pressure side pipeline is the pipeline between the condenser (indoor heat exchanger) and the evaporator (outdoor heat exchanger 104), and the low-pressure side pipeline includes the pipeline from the evaporator (outdoor heat exchanger 104) to the inlet of the four-way valve 103, and the pipeline between the outlet of the gas-liquid separator 109 and the suction port of the compressor 101.

[0121] The second end of the liquid inlet pipeline can be in communication with one, two or three of the low-pressure side pipeline, the medium-pressure side pipeline and the high-pressure side pipeline of the outdoor unit system, as needed, to collect the refrigerant from different pressure sides into the liquid storage container 110 in different working modes. When collecting the liquid, a pressure difference needs to be established between the two ends of the liquid inlet pipeline, so that the pressure at the first end of the liquid inlet pipeline is lower than that at the second end, to make at least part of the refrigerant in the refrigerant circulation loop enter the liquid storage container 110 by the pressure difference.

[0122] The second end of the liquid discharge pipeline can be connected to one, two or three of the low-pressure side pipeline, the medium-pressure side pipeline and the high-pressure side pipeline of the outdoor unit system, so as to collect the refrigerant from different pressure sides into the liquid storage container 110, and facilitate the implementation of different liquid collection modes. During the liquid collection, a pressure difference needs to be established between the two ends of the liquid inlet pipeline, so that the pressure at the first end of the liquid inlet pipeline is lower than that at the second end, so as to make at least part of the refrigerant in the refrigerant circulation loop enter the liquid storage container 110 by using the pressure difference.

[0123] The second end of the liquid inlet pipeline is connected to one, two or three of the low-pressure side pipeline, the medium-pressure side pipeline and the high-pressure side pipeline, so that the refrigerant in the liquid storage container 110 is discharged to different pressure sides, facilitating the implementation of different liquid discharge modes. The pressure at the first end of the liquid discharge pipeline is higher than that at the second end, so as to make at least part of the refrigerant in the liquid storage container 110 discharge to the refrigerant circulation loop by using the pressure difference.

[0124] For example, the high-pressure side pipeline can be referred to as a first pressure side pipeline, the medium-pressure side pipeline can be referred to as a second pressure side pipeline, and the low-pressure side pipeline can be referred to as a third pressure side pipeline, wherein the first pressure side is higher than the second pressure side, and the second pressure side is higher than the third pressure side.

[0125] This embodiment adds a liquid storage container 110 to the air conditioning system, and is connected to at least one of the low-pressure side pipeline, the medium-pressure side pipeline and the high-pressure side pipeline in the system through the liquid inlet valve and the liquid discharge valve which can realize the on-off function. On the basis of realizing the conventional refrigerant mode and the heating mode, the excess refrigerant in the refrigerant circulation loop can be collected from a specific pressure side according to the actual heat exchange demand of the air conditioning system by using the pressure difference, or the refrigerant in the liquid storage container 110 can be discharged to the refrigerant circulation loop according to the actual refrigerant demand to supplement the refrigerant, so as to achieve the best heat exchange effect and improve the heat exchange efficiency of the system.

[0126] Through such a system, the refrigerant adjustment function and the refrigerant transfer function can be realized at the same time.

[0127] In the refrigerant adjustment function, the refrigerant storage and release of the liquid storage container 110 are used to control the refrigerant amount under different operating modes, so that the system refrigerant circulation amount is consistent with the refrigerant demand under different operating modes, and the best heat exchange effect is achieved.

[0128] In the refrigerant transfer function, the problem of refrigerant accumulation in the outdoor low-pressure side after defrosting can be solved. During the defrosting period, the liquid refrigerant is stored in the liquid storage container 110. After the defrosting is completed and the heating mode is switched, the high-pressure refrigerant at the exhaust side is discharged to discharge the liquid refrigerant, so that the refrigerant quickly participates in the heating cycle, reduces the time for the heating capacity to recover to the maximum output after defrosting, and improves the heating capacity.

[0129] In some embodiments, for example, Figure 1As shown, the liquid storage container 110 also has a pressure regulating port C, and the air conditioning system further comprises a pressure relief branch 3 provided with a balance valve 112 having an on state and an off state, a first end of the pressure relief branch 3 being in communication with the pressure regulating port C, for example, a second end of the pressure relief branch 3 being in communication with the low-pressure side pipeline, which is more conducive to liquid discharge, or can also be in communication with the medium-pressure side pipeline or other positions as long as the pressure of the communication position is lower than the pressure in the liquid storage container 110; wherein in the case that the balance valve 112 is in the on state, the pressure in the liquid storage container 110 is released through the pressure relief branch 3.

[0130] Specifically, the refrigerant circulation circuit further comprises a four-way reversing valve 103 for reversing before switching between the cooling mode and the heating mode, and a gas-liquid separator 109 provided on the pipeline between the four-way reversing valve 103 and the suction port of the compressor 101. Based on this, the second end of the pressure relief branch 3 is in communication with the pipeline at the inlet of the gas-liquid separator 109, and the gaseous refrigerant discharged through the pressure relief branch 3 can first enter the gas-liquid separator 109, be separated into gas and liquid, and then the gas enters the compressor 101, preventing liquid from being sucked into the compressor 101 and causing liquid hammer.

[0131] This embodiment can, in the case that the pressure in the liquid storage container 110 is too high to normally collect liquid, release the pressure in the liquid storage container 110 to the low-pressure side pipeline by placing the balance valve 112 in the on state, establish a pressure difference between the two ends of the liquid inlet valve, and facilitate subsequent further smooth liquid collection, thereby achieving efficient storage of the refrigerant.

[0132] In some embodiments, as Figure 1 As shown, the liquid storage container 110 also has a pressure regulating port C, and the air conditioning system further comprises a pressure boosting branch 4 provided with a pressure boosting valve 111 having an on state and an off state, a first end of the pressure boosting branch 4 being in communication with the pressure regulating port C; wherein in the case that the pressure boosting valve 111 is in the on state, the high-pressure side pipeline pressurizes the liquid storage container 110.

[0133] Preferably, a second end of the pressure boosting branch 4 is in communication with the high-pressure side pipeline to provide more sufficient pressure in the liquid storage container, which is conducive to smooth liquid discharge. Alternatively, the second end of the pressure boosting branch 4 can also be in communication with the medium-pressure side pipeline or the pipeline at other positions as long as the pressure is higher than that in the liquid storage container 110.

[0134] Specifically, the second end of the pressure boosting branch 4 is connected to the pipeline between the discharge port of the compressor 101 and the four-way reversing valve 103.

[0135] The embodiment sets the pressurizing branch 4 for the liquid storage container 110, so that when the pressure in the liquid storage container 110 is low and cannot normally discharge the liquid, the pressurizing valve 111 is in the on state, the high pressure of the discharge port of the compressor 101 is introduced into the liquid storage container 110, the pressure difference between the two ends of the discharge valve is established, the discharge of the liquid is facilitated, the refrigerant in the liquid storage container 110 is discharged efficiently, the discharge efficiency is improved, the amount of refrigerant remaining in the liquid storage container 110 is reduced, the large refrigerant demand in the system is met, and the heat exchange effect is optimized.

[0136] In some embodiments, as shown in Figure 1 the liquid inlet pipeline includes a first liquid inlet branch 1, the second end of the first liquid inlet branch 1 is in communication with the medium-pressure side pipeline, the liquid inlet valve includes a first liquid inlet valve 113 arranged on the first liquid inlet branch 1; and

[0137] The liquid discharge pipeline includes a first liquid discharge branch 2, the second end of the first liquid discharge branch 2 is configured to be in communication with the low-pressure side pipeline in the cooling mode and in communication with the high-pressure side pipeline in the heating mode, and the liquid discharge valve includes a first liquid discharge valve 115 arranged on the first liquid discharge branch 2.

[0138] The second end of the first liquid inlet branch 1 is in communication with the medium-pressure side pipeline, and since the medium-pressure side pipeline contains liquid refrigerant and has a large pressure, it is beneficial to collect the liquid refrigerant in the medium-pressure side pipeline into the liquid storage container 110 to achieve smooth liquid collection. The second end of the first liquid discharge branch 2 is in communication with the low-pressure side pipeline in the cooling mode, so that the refrigerant discharged from the liquid storage container 110 can be combined with the refrigerant flowing out of the evaporator; the second end of the first liquid discharge branch 2 is in communication with the high-pressure side pipeline in the heating mode, so that the same liquid storage container 110 can be used to realize the functions of refrigerant adjustment and refrigerant transfer at the same time. When the refrigerant transfer function is realized, after the defrosting and heating operation is completed, the refrigerant in the liquid storage container 110 is discharged into the high-pressure side pipeline, so that the supplemented refrigerant can directly participate in the heat exchange on the indoor side, thereby improving the heating efficiency.

[0139] In some embodiments, as shown in Figure 1 the refrigerant circulation loop further includes a four-way reversing valve 103 and a gas-liquid separator 109, the four-way reversing valve 103 is used for reversing when switching between the cooling mode and the heating mode, and the gas-liquid separator 109 is arranged on the pipeline between the four-way reversing valve 103 and the suction port of the compressor 101;

[0140] The air conditioning system further includes a pressurizing branch 4, the second end of the first liquid discharge branch 2 is connected to the pipeline between the four-way reversing valve 103 and the evaporator, the second end of the pressurizing branch 4 is connected to the pipeline between the discharge port of the compressor 101 and the four-way reversing valve 103, and the second end of the pressure relief branch 3 is connected to the pipeline between the inlet of the gas-liquid separator 109 and the four-way reversing valve 103.

[0141] The second end of the first drainage branch 2 is connected to the pipeline between the four-way reversing valve 103 and the evaporator. In the refrigeration mode, the refrigerant discharged from the first drainage branch 2 can flow to the four-way reversing valve 103 together with the refrigerant flowing out of the evaporator, and then enter the gas-liquid separator 109 to separate the gaseous refrigerant and supplement it to the compressor. In the heating drainage mode, the refrigerant flowing out of the compressor 101 through the four-way reversing valve 103 can enter the condenser after being combined with the refrigerant discharged from the first drainage branch 2, so as to realize a large heat exchange capacity.

[0142] The second end of the pressurization branch 4 is connected to the pipeline between the exhaust port of the compressor 101 and the four-way reversing valve 103. The pressure in the liquid storage container 110 can be increased by the large pressure of the exhaust port of the compressor 101, so that the refrigerant in the liquid storage container 110 can be smoothly discharged.

[0143] The second end of the pressure relief branch 3 is connected to the pipeline between the inlet of the gas-liquid separator 109 and the four-way reversing valve 103. When the pressure in the liquid storage container 110 is too large to continue to collect liquid, the gaseous refrigerant discharged through the pressure relief branch 3 can first enter the gas-liquid separator 109, and then the gas enters the compressor 101, so as to prevent liquid from being sucked into the compressor 101 and causing liquid hammer.

[0144] In some embodiments, as shown in FIG. 1, the liquid inlet A and the pressure regulating port C are arranged in the upper region of the liquid storage container 110, and the liquid outlet B is arranged in the lower region of the liquid storage container 110. Figure 1

[0145] The liquid storage container 110 includes a top wall, a bottom wall and a side wall, which can be cylindrical or prismatic, for example. The “upper region” includes the region close to the top wall and the side wall, and the “lower region” includes the region close to the bottom wall and the side wall. For example, the liquid inlet A can be arranged on the top wall, and after the refrigerant is introduced through the liquid inlet pipeline, it can directly fall into the bottom of the liquid storage container 110 from the top, so that gas-liquid separation is not easy to occur. The liquid outlet B can be arranged in the bottom region of the side wall, so that when the amount of liquid is small, the refrigerant in the liquid storage container 110 can be smoothly discharged. The pressure regulating port C is arranged in the upper region of the side wall, so as to facilitate pressure regulation by discharging gaseous refrigerant or introducing high-pressure gaseous refrigerant.

[0146] In this embodiment, the liquid inlet A is arranged in the upper region of the liquid storage container 110, so that after the refrigerant is introduced through the liquid inlet pipeline, it can directly fall into the bottom of the liquid storage container 110 from the top, and the resistance is small, so that the liquid can be smoothly collected. The pressure regulating port C is arranged in the upper region of the liquid storage container 110, so as to facilitate pressure regulation by discharging gaseous refrigerant or introducing high-pressure gaseous refrigerant to adjust the pressure in the liquid storage container 110. The liquid outlet B is arranged in the lower region of the liquid storage container 110, so that when the amount of liquid is small, the refrigerant in the liquid storage container 110 can be smoothly discharged. ​

[0147] In some embodiments, as shown in Figure 17 the liquid inlet pipeline includes a second liquid inlet branch 5, a second end of the second liquid inlet branch 5 is in communication with the low-pressure side pipeline, and the liquid inlet valve further includes a second liquid inlet valve 119 arranged on the second liquid inlet branch 5; and / or

[0148] the liquid outlet pipeline includes a second liquid outlet branch 6, a second end of the second liquid outlet branch 6 is in communication with the medium-pressure side pipeline, and the liquid outlet valve further includes a second liquid outlet valve 117 arranged on the second liquid outlet branch 6.

[0149] In this embodiment, optionally, only the second liquid inlet branch 5 can be arranged in the air conditioning system, or both the first liquid inlet branch 1 and the second liquid inlet branch 5 can be arranged.

[0150] This embodiment is based on Figure 1 the second liquid inlet branch 5 and the second liquid outlet branch 6 are added, and in addition to the refrigeration and heating modes of collecting liquid from the medium-pressure side pipeline, discharging liquid in the refrigeration mode to the low-pressure side pipeline, and discharging liquid in the heating mode to the high-pressure side pipeline, the air conditioning system can also achieve the refrigeration and heating modes of collecting liquid from the low-pressure side pipeline and discharging liquid in the refrigeration mode to the medium-pressure side pipeline. Thus, the liquid collection and liquid discharge modes of the air conditioning system are expanded, liquid can be collected from different pressure areas, or refrigerant in the liquid storage container 110 can be discharged to different pressure areas of the system, and the optimal heat exchange effect can be achieved by flexibly selecting and adapting the liquid collection or liquid discharge mode according to the actual heat exchange demand of the air conditioning system.

[0151] In some embodiments, as shown in Figure 17 the refrigerant circulation loop further includes a four-way reversing valve 103 and a gas-liquid separator 109, the four-way reversing valve 103 is used for reversing before switching between the refrigeration mode and the heating mode, the gas-liquid separator 109 is arranged on a pipeline between the four-way reversing valve 103 and a suction port of the compressor 101, and a second end of the second liquid inlet branch 5 is connected to a position between the four-way reversing valve 103 and an inlet of the gas-liquid separator 109.

[0152] In this embodiment, the position between the four-way reversing valve 103 and the inlet of the gas-liquid separator 109 is the low-pressure side pipeline, so that the second end of the second liquid inlet branch 5 is connected to the low-pressure side pipeline to collect liquid from the low-pressure side pipeline in the refrigeration or heating mode, and the second end of the second liquid inlet branch 5 is connected to a position before the inlet of the gas-liquid separator 109, and the pipeline section contains more liquid refrigerant, which is convenient for liquid collection.

[0153] In some embodiments, as shown in Figure 21 and Figure 22As shown, the four-way reversing valve 103 and the second end of the second liquid inlet branch 5 form a main pipeline section a, the second end of the second liquid inlet branch 5 and the inlet of the gas-liquid separator 109 form a first branch pipeline section b, the main pipeline section a communicates with the second liquid inlet branch 5 and the first branch pipeline section b, and the second liquid inlet branch 5 is a second branch pipeline section c in the main pipeline section a. Figure 22

[0154] The refrigerant flow resistance of the first branch pipeline section b is greater than the refrigerant flow resistance of the second liquid inlet branch 5.

[0155] This embodiment considers that when the low-pressure side pipeline is drained, the pressure difference between the low-pressure side pipeline and the liquid storage container 110 is small. By making the refrigerant flow resistance of the first branch pipeline section b greater than the refrigerant flow resistance of the second liquid inlet branch 5, the refrigerant in the main pipeline section a can be preferentially drained to the second liquid inlet branch 5 to smoothly realize low-pressure side drainage.

[0156] In some embodiments, as shown in Figures 22 to 24 , the height of the second liquid inlet branch 5 is lower than the length of the first branch pipeline section b near the second end of the second liquid inlet branch 5; and / or

[0157] The first branch pipeline section b is provided with a resistance increasing part 10 configured to increase the refrigerant flow resistance of the first branch pipeline section b.

[0158] As shown in Figure 22 , the main pipeline section a and the first branch pipeline section b are horizontally arranged and flush, and the second branch pipeline section c is bent downward to form an L-shaped pipeline, and the horizontal section of the L-shaped pipeline is lower than the first branch pipeline section b. By setting the height difference, the refrigerant preferentially flows into the lower second liquid inlet branch 5.

[0159] As shown in Figure 24 , the main pipeline section a is bent upward to form an L-shaped pipeline, the second liquid inlet branch 5 is bent downward to form an L-shaped pipeline, the horizontal section of the main pipeline section a is higher than the horizontal section of the second liquid inlet branch 5, and the refrigerant preferentially flows into the lower second liquid inlet branch 5.

[0160] As shown in Figure 23 , the first branch pipeline section b is provided with a resistance increasing part 10, for example, the resistance increasing part 10 is a throttling or a curved pipeline, which can increase the refrigerant flow resistance in the first branch pipeline section b, so that the refrigerant preferentially flows into the lower second liquid inlet branch 5.

[0161] ​The pipeline of the embodiment can make the refrigerant flow resistance of the first branch pipeline section b greater than the refrigerant flow resistance of the second liquid inlet branch 5 through different structural forms, so that the refrigerant in the total pipeline section a is preferentially flowed to the second liquid inlet branch 5 for liquid collection, to smoothly realize low-pressure side liquid collection. Among them, the above resistance relationship is realized through the height difference of the pipeline, only need to set a specific pipeline position when the system is laid out; by setting the resistance increasing part 10, the resistance adjustment can be realized by changing the local structure of the pipeline.

[0162] In some embodiments, as shown in Figures 32 to 37 The liquid inlet pipeline includes the second liquid inlet branch 5 and the pressurization branch 4, the second end of the second liquid inlet branch 5 is in communication with the low-pressure side pipeline, and the liquid inlet valve includes a second liquid inlet valve 119 arranged on the second liquid inlet branch 5; the pressurization branch 4 is provided with a pressurization valve 111 having an on state and an off state, the first end of the pressurization branch 4 is in communication with the pressure regulating port C of the liquid storage container 110, for example, the second end of the pressurization branch 4 is in communication with the high-pressure side pipeline, or it can also be in communication with the medium-pressure side pipeline or other positions, as long as the pressure of the communication position is greater than the pressure inside the liquid storage container 110;

[0163] The liquid discharge pipeline includes the first liquid discharge branch 2 and / or the second liquid discharge branch 6, the second end of the first liquid discharge branch 2 is configured to be in communication with the low-pressure side pipeline in the refrigeration mode and in communication with the high-pressure side pipeline in the heating mode; the second end of the second liquid discharge branch 6 is in communication with the medium-pressure side pipeline; the liquid discharge valve includes a first liquid discharge valve 115 arranged on the first liquid discharge branch 2 and a second liquid discharge valve 117 arranged on the second liquid discharge branch 6;

[0164] The refrigerant circulation loop is provided with a second control valve 121 on the pipeline section between the second end of the second liquid inlet branch 5 and the suction port of the compressor 101; the liquid storage container 110 has a gas outlet D, and the air conditioning system further includes a first control valve 120, the first end of the first control valve 120 is in communication with the gas outlet D, and the second end of the first control valve 120 is connected to the pipeline section between the second control valve 121 and the suction port of the compressor 101.

[0165] Among them, the first control valve 120 and the second control valve 121 both have an on state and an off state.

[0166] Optionally, the air conditioning system is simultaneously provided with the first liquid inlet branch 1 and the second liquid inlet branch 5, and one of the first liquid inlet branch 1 and the second liquid inlet branch 5 can be selected to realize liquid inlet according to actual needs, or liquid inlet is realized through both branches at the same time, and the air conditioning system is simultaneously provided with the first liquid discharge branch 2 or the second liquid discharge branch 6, so as to have two liquid inlet branches and one liquid discharge branch.

[0167] The embodiment has a refrigeration, heating low-pressure side liquid collection mode, refrigeration medium-pressure side liquid discharge mode and heating high-pressure side liquid discharge mode. On the basis of realizing the liquid collection and liquid discharge functions, the gas-liquid separator can be omitted, the system structure is simplified, and the cost is reduced. Through accurate control of multiple valves, the risk of liquid suction of the compressor 101 can be prevented.

[0168] Secondly, the present disclosure provides a control method based on the above-mentioned air conditioning system. In some embodiments, the control method comprises:

[0169] Liquid collection mode: the inlet valve is in an on state, and the pressure at the first end of the inlet pipeline is less than the pressure at the second end, so that the refrigerant in the refrigerant circulation loop is stored in the liquid storage container 110;

[0170] Liquid discharge mode: when it is necessary to discharge the refrigerant in the liquid storage container 110 to the refrigerant circulation loop, the liquid discharge valve is in an on state, and the pressure at the first end of the liquid discharge pipeline is greater than the pressure at the second end.

[0171] When the air conditioning system is in load conversion or mode conversion, that is, the number of indoor units in a multi-split air conditioner changes, the refrigerant in the refrigerant circulation loop can be adapted to the working requirements through the liquid collection mode and the liquid discharge mode due to the large change in the air conditioning operating state. When the air conditioning system is just switched from the defrosting mode to the heating state for a period of time, it is necessary to accelerate the liquid discharge, which is beneficial to the rapid entry of the liquid refrigerant into the system to participate in the circulation.

[0172] The air conditioning system control method of the embodiment can be communicated with at least one of the low-pressure side pipeline, the medium-pressure side pipeline and the high-pressure side pipeline in the system through the inlet valve and the liquid discharge valve with on-off function. On the basis of realizing the conventional refrigerant mode and the heating mode, the excess refrigerant in the refrigerant circulation loop can be collected from a specific pressure side according to the actual heat exchange requirements of the air conditioning system by using the pressure difference, or the refrigerant in the liquid storage container 110 can be discharged to the refrigerant circulation loop according to the actual refrigerant requirement to supplement the refrigerant circulation loop, so as to achieve the best heat exchange effect and improve the system heat exchange efficiency.

[0173] In some embodiments, for example Figures 1 to 9 the first embodiment shown in FIG. 1, and Figures 10 to 16 the second embodiment shown in FIG. 2, the air conditioning system further comprises a pressure relief branch 3 and a pressure boosting branch 4. The pressure relief branch 3 is provided with a balance valve 112. The first end of the pressure relief branch 3 is communicated with the pressure regulating port C of the liquid storage container 110, and the second end of the pressure relief branch 3 can be communicated with the low-pressure side pipeline or the medium-pressure side pipeline. The pressure boosting branch 4 is provided with a pressure boosting valve 111. The first end of the pressure boosting branch 4 is communicated with the pressure regulating port C, and the second end of the pressure boosting branch 4 is communicated with the high-pressure side pipeline.

[0174] The liquid inlet pipeline includes a first liquid inlet branch 1, and a second end of the first liquid inlet branch 1 is in communication with the medium-pressure side pipeline. The liquid inlet valve includes a first liquid inlet valve 113 arranged on the first liquid inlet branch 1.

[0175] The liquid collection mode includes a refrigeration liquid collection mode and a heating liquid collection mode. In the refrigeration liquid collection mode and the heating liquid collection mode, the liquid discharge valve and the pressurizing valve 111 are both in an off state, the first liquid inlet valve 113 is in an on state, and the balance valve 112 is in an on state when a pressure difference between two ends of the first liquid inlet valve 113 is less than a preset threshold, so as to release the pressure in the liquid storage container 110.

[0176] In the refrigeration liquid collection mode and the heating liquid collection mode, the liquid discharge valve and the pressurizing valve 111 are both in an off state, the first liquid inlet valve 113 is in an on state, and the balance valve 112 is in an on state when a pressure difference between two ends of the first liquid inlet valve 113 is less than a preset threshold, so as to release the pressure in the liquid storage container 110. Figure 3 FIG. 4 is a schematic diagram of the refrigeration liquid collection mode, and the first liquid inlet valve 113 is in an on state. The liquid-state refrigerant flowing out of the outdoor heat exchanger 104 enters the liquid storage container 110 through the first liquid inlet valve 113, and the liquid collection in the refrigeration mode is completed. At the same time, when the pressure P0 in the liquid storage container 110 is relatively high, the pressure difference between two ends of the first liquid inlet valve 113 is relatively small, and the balance valve 112 is in an on state. The second end of the balance valve 112 is connected to the low-pressure side pipeline, so that the pressure in the liquid storage container 110 is released, and the liquid collection process is smoothly performed.

[0177] Figure 6 FIG. 5 is a schematic diagram of the heating liquid collection mode, and the first liquid inlet valve 113 is in an on state. The liquid-state refrigerant flowing out of the indoor heat exchanger 122 enters the liquid storage container 110 through the first liquid inlet valve 113, and the liquid collection in the heating mode is completed. At the same time, when the pressure P0 in the liquid storage container 110 is relatively high, the pressure difference between two ends of the first liquid inlet valve 113 is relatively small, and the balance valve 112 is in an on state. The second end of the balance valve 112 is connected to the low-pressure side pipeline, so that the pressure in the liquid storage container 110 is released, and the liquid collection process is smoothly performed.

[0178] In the refrigeration mode and the heating mode, the first liquid inlet valve 113 is in an on state, the refrigerant in the medium-pressure side pipeline enters the liquid storage container 110 to realize the liquid collection, and when the pressure in the liquid storage container 110 is relatively high and the liquid collection cannot be normally performed, the balance valve 112 is in an on state, the pressure in the liquid storage container 110 is released to the low-pressure side pipeline through the pressure relief branch 3, the pressure difference between two ends of the first liquid inlet valve 113 is established, and the subsequent liquid collection is smoothly performed, so that the refrigerant is efficiently stored.

[0179] In some embodiments, for example Figures 10 to 16 As shown in the second embodiment, the liquid discharge pipeline includes a first liquid discharge branch 2, and a second end of the first liquid discharge branch 2 is configured to be in communication with the low-pressure side pipeline in the refrigeration mode and in communication with the high-pressure side pipeline in the heating mode. The liquid discharge valve includes a first liquid discharge valve 115 arranged on the first liquid discharge branch 2. The liquid discharge mode further includes a refrigeration liquid discharge mode and a heating liquid discharge mode.

[0180] like Figure 13 As shown, in the refrigeration drain mode, the first drain valve 115 is in the on state. At this time, the first inlet valve 113 and the balance valve 112 are both in the off state. Alternatively, the draining through the first drain valve 115 and the inlet through the first inlet valve 113 can be carried out simultaneously.

[0181] like Figure 15 and Figure 16 In the heating and draining mode, the first inlet valve 113 is first turned on. When the pressure in the liquid storage container 110 reaches the pressure at the second end of the first inlet branch 1, the first inlet valve 113 is turned off. Then, the compressor 101 is reduced in frequency or stopped, and the first drain valve 115 is turned on.

[0182] In the heating and draining mode, the pressure at the discharge port of compressor 101 is marked as the first pressure point P1, the pressure downstream of the first drain valve 115 is marked as the second pressure point P2, and the pressure at the second end of the first inlet branch 1 is marked as the third pressure point P3, which is the position between the outdoor unit throttling element 105 and the liquid pipe valve 106. In heating mode operation, P1 > P2 > P3.

[0183] First, such as Figure 15 As shown, after the first inlet valve 113 is turned on, the pressure in the liquid storage container 110 is adjusted to a medium pressure state, that is, the pressure in the liquid storage container 110 P0 = the third pressure point P3, and then the first inlet valve 113 is switched to the off state. At this time, P1 > P2 > P3 = P0, which can maintain the pressure in the liquid storage container 110.

[0184] After that, as Figure 16 As shown, the compressor 101 is reduced in frequency or stopped. At this time, the pressures of the first pressure point P1, the second pressure point P2, and the third pressure point P3 are reduced and are denoted as P1', P2', and P3'. At this time, the pressure P0 in the liquid storage container 110 remains unchanged, P0 > P1' > P2' > P3'. At this time, the first drain valve 115 is turned on, and the refrigerant in the liquid storage container 110 can be discharged.

[0185] In the refrigeration drain mode, since the drain is directed to the low-pressure side pipeline, the drain function can be achieved solely by relying on the first drain valve 115, simplifying the control method. In the heating drain mode, since the drain is directed to the high-pressure side pipeline, the pressure inside the liquid storage container 110 is first increased and maintained through the first inlet valve 113. However, since the second end of the first inlet valve 113 is connected to the medium-pressure side pipeline, it is still difficult to drain the refrigerant. By reducing the frequency of the compressor 101 or stopping its operation, the pressure at the second end of the first drain branch 2 can be reduced, thereby allowing the refrigerant in the liquid storage container 110 to drain smoothly.

[0186] In some embodiments, for example Figures 1 to 9 The first embodiment shown is consistent with the second embodiment. The air conditioning system further comprises a pressurization branch 4, provided with a pressurization valve 111, the first end of the pressurization branch 4 being in communication with the pressure regulating port C; the liquid discharge pipeline comprises a first liquid discharge branch 2, the second end of the first liquid discharge branch 2 being configured to be in communication with the low-pressure side pipeline in the refrigeration mode and in communication with the high-pressure side pipeline in the heating mode, and the liquid discharge valve comprises a first liquid discharge valve 115 provided on the first liquid discharge branch 2;

[0187] The liquid discharge mode comprises: a first refrigeration liquid discharge mode, a second refrigeration liquid discharge mode, a first heating liquid discharge mode, and a second heating liquid discharge mode; wherein,

[0188] As shown in Figure 4 In the first refrigeration liquid discharge mode, the first liquid discharge valve 115 is in the on state, the pressurization valve 111 is in the on state when the internal pressure P0 of the liquid storage container 110 drops to the level of the low-pressure side pipeline, and the first liquid inlet valve 113 and the balance valve 112 are both in the off state;

[0189] As shown in Figure 5 In the second refrigeration liquid discharge mode, the balance valve 112 is in the on state, and the first liquid inlet valve 113, the first liquid discharge valve 115, and the pressurization valve 111 are all in the off state;

[0190] As shown in Figure 7 In the first heating liquid discharge mode, the pressurization valve 111 is in the on state to raise the pressure inside the liquid storage container 110 to the pressure at the second end of the pressurization branch 4, and the first liquid discharge valve 115 is in the on state; the first liquid inlet valve 113 and the balance valve 112 are in the off state. Preferably, the pressurization valve 111 is first brought to the on state, and then the first liquid discharge valve 115 is brought to the on state after the pressure inside the liquid storage container 110 has risen to the pressure at the second end of the pressurization branch 4, making it easier to reach the required pressure for liquid discharge. Alternatively, the pressurization valve 111 and the first liquid discharge valve 115 can be opened simultaneously.

[0191] Specifically, the compressor 101 exhaust port pressure is marked as the first pressure point P1, and the pressure downstream of the first liquid discharge valve 115 is marked as the second pressure point P2. In the heating mode, P1>P2, the pressurization valve 111 is opened in this state, the internal pressure P0 of the liquid storage container 110 is P1>P2, and the first liquid discharge valve 115 is opened to discharge the refrigerant in the liquid storage container 110.

[0192] As shown in Figure 8 and Figure 9As shown, in the second heating liquid discharge mode, the pressurizing valve 111 is first in the on state, and when the pressure inside the liquid storage container 110 rises to the pressure at the second end of the pressurizing branch 4, the pressurizing valve 111 is switched to the off state; then, the compressor 101 is reduced in frequency or stopped, and at this time, the first liquid discharge valve 115 is in the on state.

[0193] Specifically, first, as shown, the pressurizing valve 111 is in the on state, and then the pressure inside the liquid storage container 110 is adjusted to a high-pressure state, that is, the pressure P0 inside the liquid storage container 110 is the first pressure point P1, that is, P0 = P1; at the same time, P0 > P2, that is, P0 = P1 > P2. Then, the pressurizing valve 111 and the first liquid discharge valve 115 are in the off state, so that the pressure inside the liquid storage container 110 is maintained. Figure 8

[0194] Then, as shown, the compressor 101 is reduced in frequency or stopped, and at this time, the pressures of the first pressure point P1 and the second pressure point P2 are reduced, denoted as P1' and P2', and at this time, the pressure P0 inside the liquid storage container 110 is unchanged, P0 > P1' > P2', and at this time, the first liquid discharge valve 115 is in the on state, so that the refrigerant inside the liquid storage container 110 is discharged. Figure 19 The air conditioning system of this embodiment has two liquid discharge modes in the cooling and heating modes, which can better flexibly select different liquid discharge modes according to the needs, optimize the heat exchange effect, and specifically:

[0195] In the first cooling liquid discharge mode, the second end of the first liquid discharge branch 2 is connected to the low-pressure side pipeline, and after the first liquid discharge valve 115 is opened, the refrigerant can enter the system circulation, and when the pressure inside the liquid storage container 110 drops to the extent that it cannot be discharged, the pressure inside the liquid storage container 110 is increased by opening the pressurizing valve 111 for a predetermined time, so that the refrigerant can continue to be discharged.

[0196] In the second cooling liquid discharge mode, since the second end of the balance valve 112 is connected to the low-pressure side pipeline, the balance valve 112 is in the on state, so that the refrigerant inside the liquid storage container 110 can be discharged into the system circulation, and at this time, the discharged refrigerant is in a gaseous state, which is suitable for the case where a small amount of refrigerant needs to be supplemented into the system.

[0197] In the first heating liquid discharge mode, since the second end of the first liquid discharge branch 2 is connected to the high-pressure side pipeline, by making the pressurizing valve 111 in the on state during liquid discharge, the high-pressure pipeline of the exhaust port of the compressor 101 can be used to pressurize the inside of the liquid storage container 110, so that the liquid discharge in the heating mode is realized smoothly.

[0198]

[0199] ​​In the second heating liquid discharge mode, the pressure in the liquid storage container 110 is first increased and pressure is maintained by the pressurizing valve 111. Since the second end of the first liquid discharge branch 2 is connected to the high-pressure side pipeline, it is difficult to discharge a large amount of refrigerant, and a large amount of refrigerant remains in the liquid storage container 110. By reducing the frequency of the compressor 101 or stopping the operation, the pressure at the second end of the first liquid discharge branch 2 can be reduced, so that the refrigerant in the liquid storage container 110 can be smoothly discharged, and the discharge amount of the refrigerant can be increased.

[0200] In some embodiments, as shown in a third embodiment, Figures 17 to 25 the liquid inlet pipeline includes a second liquid inlet branch 5, the second end of the second liquid inlet branch 5 is in communication with the low-pressure side pipeline, and the liquid inlet valve further includes a second liquid inlet valve 119 arranged on the second liquid inlet branch 5; the liquid discharge pipeline includes a second liquid discharge branch 6, the second end of the second liquid discharge branch 6 is in communication with the medium-pressure side pipeline, and the liquid discharge valve further includes a second liquid discharge valve 117 arranged on the second liquid discharge branch 6; the second end of the second liquid inlet branch 5 and the inlet of the gas-liquid separator 109 form a first branch pipeline section b;

[0201] The liquid collection mode further includes: a refrigeration low-pressure side liquid collection mode and a heating low-pressure side liquid collection mode. In the refrigeration low-pressure side liquid collection mode and the heating low-pressure side liquid collection mode, the second liquid inlet valve 119 is in an open state, and the balance valve 112 is opened when the pressure in the liquid storage container 110 is increased to a case where the flow resistance of the refrigerant in the second liquid inlet branch 5 is greater than the first branch pipeline section b; and / or

[0202] The liquid discharge mode further includes: a refrigeration medium-pressure side liquid discharge mode. In the refrigeration medium-pressure side liquid discharge mode, the pressurizing valve 111 is first in an open state, and when the pressure in the liquid storage container 110 is increased to the pressure at the second end of the pressurizing branch 4, the pressurizing valve 111 is switched to a closed state. Then, the second liquid discharge valve 117 is opened.

[0203] Specifically, as shown in Figure 19 in the refrigeration low-pressure side liquid collection mode, when the second liquid inlet valve 119 is in an open state, the low-pressure side liquid refrigerant flows back from the gas pipe valve 107, most of the refrigerant enters the liquid storage container 110 through the second liquid inlet branch 5, and a small amount of refrigerant flows through the gas-liquid separator 109 to return to the low-pressure side pipeline through the first branch pipeline section b. When the internal pressure P0 of the liquid storage container 110 is increased to be greater than the flow resistance of the second branch pipeline section c, liquid collection cannot continue, and at this time the balance valve 112 can be opened to reduce the flow resistance of the first branch pipeline section b.

[0204] As shown in Figure 21 in the heating low-pressure side liquid collection mode, the valve body operates in the same way as Figure 19 the refrigeration low-pressure side liquid collection mode.

[0205] As shown in Figure 20As shown, in the refrigeration medium pressure side discharge mode, the pressurizing valve 111 is first in the on state, and after the pressure P0 in the liquid storage container 110 is raised to the first pressure point P1, the pressurizing valve 111 is switched to the off state; then the second discharge valve 117 is in the on state, at this time the pressure P0 in the liquid storage container 110 is higher than the fourth pressure point P4, the fourth pressure point P4 is the pressure of the second end of the second discharge branch 6, and the refrigerant in the liquid storage container 110 can be discharged through the second discharge valve 117 into the medium pressure side pipeline of the system to participate in circulation.

[0206] As shown in FIG. 1, the first embodiment of the application is a refrigeration system with a liquid storage container 110, a liquid inlet pipeline, a liquid outlet pipeline, a refrigeration pipeline, a high pressure side pipeline, a medium pressure side pipeline and a low pressure side pipeline. Figure 25 As shown, in the refrigeration medium pressure side discharge mode, the pressurizing valve 111 is first in the on state, and after the pressure P0 in the liquid storage container 110 is raised to the first pressure point P1, the pressurizing valve 111 is switched to the off state; then the second discharge valve 117 is in the on state, at this time the pressure P0 in the liquid storage container 110 is higher than the fourth pressure point P4, the fourth pressure point P4 is the pressure of the second end of the second discharge branch 6, and the refrigerant in the liquid storage container 110 can be discharged through the second discharge valve 117 into the medium pressure side pipeline of the system to participate in circulation.

[0207] The second embodiment is based on the first embodiment, and adds a second liquid inlet branch 5 and a second discharge branch 6. In addition to the refrigeration and heating modes of the first embodiment, the refrigeration and heating modes can also collect liquid from the low pressure side pipeline and discharge refrigerant to the medium pressure side pipeline in the refrigeration mode.

[0208] In some embodiments, as shown in FIG. 4, the fourth embodiment cancels the first liquid inlet valve 113 compared with the third embodiment, and the control mode of the refrigeration low pressure side liquid collection mode, the heating low pressure side liquid collection mode, the refrigeration medium pressure side discharge mode and the heating high pressure side discharge mode of the fourth embodiment is consistent with that of the third embodiment. Figures 26 to 31 In some embodiments, as shown in FIG. 5, the liquid inlet pipeline includes a second liquid inlet branch 5 and a pressurizing branch 4, the second end of the second liquid inlet branch 5 is in communication with the low pressure side pipeline, and the liquid inlet valve includes a second liquid inlet valve 119 arranged on the second liquid inlet branch 5; the pressurizing branch 4 is provided with a pressurizing valve 111, the first end of the pressurizing branch 4 is in communication with the pressure regulating port C of the liquid storage container 110, and the second end of the pressurizing branch 4 is in communication with the high pressure side pipeline.

[0209] Figures 32 to 37 The liquid inlet pipeline includes a second liquid inlet branch 5 and a pressurizing branch 4, the second end of the second liquid inlet branch 5 is in communication with the low pressure side pipeline, and the liquid inlet valve includes a second liquid inlet valve 119 arranged on the second liquid inlet branch 5; the pressurizing branch 4 is provided with a pressurizing valve 111, the first end of the pressurizing branch 4 is in communication with the pressure regulating port C of the liquid storage container 110, and the second end of the pressurizing branch 4 is in communication with the high pressure side pipeline.

[0210] The liquid inlet pipeline includes a second liquid inlet branch 5 and a pressurizing branch 4, the second end of the second liquid inlet branch 5 is in communication with the low pressure side pipeline, and the liquid inlet valve includes a second liquid inlet valve 119 arranged on the second liquid inlet branch 5; the pressurizing branch 4 is provided with a pressurizing valve 111, the first end of the pressurizing branch 4 is in communication with the pressure regulating port C of the liquid storage container 110, and the second end of the pressurizing branch 4 is in communication with the high pressure side pipeline. ​

[0211] The refrigerant circulation loop is provided with a second control valve 121 on the pipe section between the second end of the second liquid inlet branch 5 and the suction port of the compressor 101; the liquid storage container 110 has a gas outlet port, and the air conditioning system further comprises a first control valve 120, a first end of the first control valve 120 being in communication with the gas outlet port, and a second end of the first control valve 120 being connected to the pipe section between the second control valve 121 and the suction port of the compressor 101;

[0212] The liquid collection mode includes a refrigeration low-pressure-side liquid collection mode and a heating low-pressure-side liquid collection mode, as shown in Figure 34 and Figure 36 In the refrigeration low-pressure-side liquid collection mode and the heating low-pressure-side liquid collection mode, the second liquid inlet valve 119 and the first control valve 120 are in the on state, and the other valves are in the off state.

[0213] In the refrigeration low-pressure-side liquid collection mode, the high-pressure gaseous refrigerant discharged by the compressor 101 enters the liquid storage container 110 in sequence through the four-way valve 103, the outdoor heat exchanger 104, the outdoor unit throttling element 105, the indoor heat exchanger 122, the four-way valve 103, and the second liquid inlet valve 119, and then the gaseous refrigerant is discharged through the first control valve 120 to return to the compressor 101. In this process, the liquid storage container 110 becomes part of the main circulation loop. Since the gaseous refrigerant is discharged through the first control valve 120, the discharge speed is slow, and therefore it is suitable for occasions with small heat exchange requirements.

[0214] In the heating low-pressure-side liquid collection mode, the high-pressure gaseous refrigerant discharged by the compressor 101 enters the liquid storage container 110 in sequence through the four-way valve 103, the indoor heat exchanger 122, the outdoor unit throttling element 105, the outdoor heat exchanger 104, the four-way valve 103, and the second liquid inlet valve 119, and then the gaseous refrigerant is discharged through the first control valve 120 to return to the compressor 101. In this process, the liquid storage container 110 becomes part of the main circulation loop. Since the gaseous refrigerant is discharged through the first control valve 120, the discharge speed is slow, and therefore it is suitable for occasions with small heat exchange requirements.

[0215] This embodiment can eliminate the gas-liquid separator, simplify the system structure, and reduce the cost. Through precise control of multiple valves, the risk of liquid suction of the compressor 101 can be prevented.

[0216] In some embodiments, the liquid discharge mode includes a refrigeration medium-pressure-side liquid discharge mode and a heating high-pressure-side liquid discharge mode,

[0217] As shown in Figure 35As shown, in the medium-pressure side drain mode of refrigeration, the first control valve 120 is in the off state and the second control valve 121 is in the on state. Then, the pressure valve 111 is in the on state to increase the pressure in the liquid storage container 110 and the second drain valve 117 is in the on state.

[0218] Preferably, the pressurizing valve 111 is first turned on, and when the pressure in the liquid storage container 110 rises to the pressure at the second end of the pressurizing branch 4, the pressurizing valve 111 is switched off. Then, the second drain valve 117 is opened. This method makes it easier to achieve pressurization and ensures a smooth draining process. Optionally, the pressurizing valve 111 and the second drain valve 117 can also be opened simultaneously.

[0219] like Figure 37 As shown, in the high-pressure side drain mode for heating, the first control valve 120 is in the off state and the second control valve 121 is in the on state. Then, the pressure valve 111 is in the on state to increase the pressure inside the liquid storage container 110 and to turn on the first drain valve 115.

[0220] Preferably, the pressurizing valve 111 is first turned on, and when the pressure inside the liquid storage container 110 rises to the pressure at the second end of the pressurizing branch 4, the pressurizing valve 111 is switched off. Then, the first drain valve 115 is turned on. This method makes it easier to achieve pressurization and ensures a smooth draining process. Optionally, the pressurizing valve 111 and the first drain valve 115 can also be opened simultaneously.

[0221] In this embodiment, during the medium-pressure side drain mode in refrigeration, the second control valve 121 is in the on state, connecting to the low-pressure side pipeline. Since the second end of the second drain branch 6 is connected to the medium-pressure side pipeline, the pressure inside the liquid storage container needs to be increased through the pressure-boosting valve 111 to facilitate smooth draining. During the high-pressure side drain mode in heating, since the second end of the first drain branch 2 is connected to the high-pressure side pipeline, the pressure inside the liquid storage container needs to be increased through the pressure-boosting valve 111 to facilitate smooth draining.

[0222] The following describes in detail the five embodiments shown in the accompanying drawings. In each embodiment, the valve can be a solenoid valve and can be controlled by a controller.

[0223] First embodiment, such as Figures 1 to 9 As shown.

[0224] The air conditioning system includes a compressor 101, an outdoor heat exchanger 104, an indoor heat exchanger 122, a first liquid inlet valve 113, a liquid storage container 110, a gas-liquid separator 109, a four-way reversing valve 103, a first drain valve 115, a pressurizing valve 111, and a balancing valve 112. A liquid pipe valve 106 and a gas pipe valve 107 are respectively installed at the two refrigerant interfaces of the indoor heat exchanger 122. The liquid pipe valve 106 is located on the pipeline between the indoor heat exchanger 122 and the outdoor heat exchanger 104, and the gas pipe valve 107 is located on the pipeline connecting to the four-way reversing valve 103. Furthermore, a first pressure sensor 102 is installed between the compressor 101 and the four-way reversing valve 103 to detect the refrigerant pressure at the first pressure point P1; a second pressure sensor 108 is installed between the gas-liquid separator 109 and the four-way reversing valve 103 to detect the pressure at the inlet of the gas-liquid separator 109. The air conditioning system also includes an unloading valve 114. The first end of the unloading valve 114 is connected between the first liquid inlet branch 1 and the first liquid inlet valve 113 and the liquid inlet A. The second end of the unloading valve 114 is connected to the pipeline between the inlet of the gas-liquid separator 109 and the four-way reversing valve 103. It is used to release pressure when the pressure in the first liquid inlet branch 1 exceeds the safety threshold.

[0225] The air conditioning system of the first embodiment has a conventional cooling mode, such as Figure 1 As shown, the first inlet valve 113, the first outlet valve 115, the pressurizing valve 111, and the balancing valve 112 are all in the off state; and in the conventional heating mode, such as Figure 2 As shown, the first inlet valve 113, the first outlet valve 115, the pressurizing valve 111, and the balancing valve 112 are all in the off state.

[0226] In addition, the air conditioning system also has the following liquid collection mode and liquid drainage mode:

[0227] A. Cooling liquid collection mode: such as Figure 3 As shown, the first inlet valve 113 is in the closed state, while the pressurizing valve 111, the balancing valve 112, and the first drain valve 115 are closed. The second end of the first inlet valve 113 is connected to the medium-pressure side of the system. When this valve is in the closed state, a portion of the refrigerant flowing from the outdoor heat exchanger 104 passes through the first inlet valve 113 and enters the liquid storage container 110, completing the liquid collection in the cooling mode. Simultaneously, when the internal pressure P0 is high and the pressure difference across the first inlet valve 113 is small, the balancing valve 112 is in the closed state. The second end of the balancing valve 112 is connected to the low-pressure side of the system, allowing for pressure relief inside the liquid storage container 110.

[0228] B. First refrigerant discharge mode: (e.g.) Figure 4As shown, the pressurizing valve 111 and the first discharge valve 115 are in the on state, and the first inlet valve 113 and the balance valve 112 are in the off state. The second end of the first discharge valve 115 is connected to the low pressure side of the system, and the valve is in the on state. The refrigerant in the liquid storage container 110 is discharged and enters the system circulation through the first discharge valve 115. When the internal pressure P0 of the liquid storage container 110 drops to the same level as the low pressure, and cannot be discharged any more, the pressurizing valve 111 in the on state can be preset for a period of time to increase the internal pressure P0 of the liquid storage container 110.

[0229] C, second refrigeration discharge mode: as shown in Figure 5 , the balance valve 112 is in the on state, and the pressurizing valve 111, the first inlet valve 113 and the first discharge valve 115 are in the off state. The second end of the balance valve 112 is connected to the low pressure side of the system, and the valve is in the on state. The refrigerant in the liquid storage container 110 is discharged and enters the system circulation through the balance valve 112.

[0230] D, heating collection mode: as shown in Figure 6 , the same as the refrigeration collection mode.

[0231] For the convenience of understanding, two pressure point concepts are introduced. The first pressure point is located after the compressor 101 and before the four-way valve 103, and the pressure at this point is P1; the second pressure point is located after the four-way valve 103 and before the gas pipe valve 107, and the pressure at this point is P2.

[0232] E, first heating discharge mode: as shown in Figure 7 , the pressurizing valve 111 and the first discharge valve 115 are in the on state, and the first inlet valve 113 and the balance valve 112 are in the off state. At this time, the second end of the pressurizing valve 111 is connected to the first pressure point P1; the second end of the first discharge valve 115 is connected to the second pressure point P2, and P1>P2. In this mode, the pressurizing valve 111 in the on state, the internal pressure P0 of the liquid storage container 110 is P1>P2, and the first discharge valve 115 in the on state can realize the discharge of the refrigerant in the liquid storage container 110.

[0233] F, second heating discharge mode:

[0234] ①First, as shown in Figure 8 , the pressurizing valve 111 in the on state is used to adjust the liquid storage container 110 to a high pressure state, and then the pressurizing valve 111 is closed. At this time, the internal pressure P0 of the liquid storage container 110 is equal to the first pressure point P1, that is, P0=P1; at the same time, P0 is higher than the first end of the first discharge valve 115, that is, P0>P2. P0=P1>P2.

[0235] ②After that, as shown in Figure 9As shown, when compressor 101 reduces its frequency or stops, the pressures at the first and second pressure points decrease, denoted as P1' and P2'. At this time, the internal pressure P0 of the liquid storage container 110 remains unchanged, P0 > P1' > P2'. The first drain valve 115, which is in the on state at this time, can discharge the refrigerant.

[0236] Under different operating modes, the actions of each valve connected to the liquid storage container 110 are as follows:

[0237] Table 1 Valve body operation under each working mode of the first embodiment

[0238]

[0239] Second embodiment, such as Figures 10 to 16 As shown.

[0240] Based on Example 1, the pressure valve 111 and the pressure branch 4 are removed, while the remaining components, liquid storage container 110, and valve body connection features remain the same.

[0241] The air conditioning system of the second embodiment has a conventional cooling mode, such as Figure 10 As shown, the first inlet valve 113, the first outlet valve 115, and the balance valve 112 are all in the off state; and in the conventional heating mode, such as Figure 11 As shown, the first inlet valve 113, the first outlet valve 115, and the balance valve 112 are all in the off state.

[0242] In addition, the air conditioning system also has the following liquid collection mode and liquid drainage mode:

[0243] A. Cooling liquid collection mode: such as Figure 12 As shown, it is consistent with the cooling liquid collection mode of the first embodiment.

[0244] B. Refrigerant discharge mode: (e.g., refrigerant discharge mode) Figure 13 As shown, the first drain valve 115 is in the on state, while the first inlet valve 113 and the balance valve 112 are in the off state. The second end of the first drain valve 115 is connected to the low-pressure side of the system. When this valve is in the on state, the refrigerant in the liquid storage container 110 is discharged and enters the system circulation through the first drain valve 115.

[0245] C. Heating and liquid collection mode: such as Figure 14 As shown, it is consistent with the heat collection mode in Example 1.

[0246] For ease of understanding, the concept of a third pressure point is introduced. The third pressure point is located after the gas pipe valve 107 in the heating flow direction and before the throttling element 105 of the outdoor heating unit; the pressure here is denoted as P3. In heating mode operation, P1 > P2 > P3.

[0247] D. Heating and draining mode:

[0248] ① First, such as Figure 15 As shown, by turning on the first inlet valve 113, the liquid storage container 110 is first adjusted to a medium pressure state, that is, the internal pressure P0 of the liquid storage container 110 is equal to the third pressure point P3, and then the first inlet valve 113 is switched to the off state. At this time, P1 > P2 > P3 = P0.

[0249] ②After that, as Figure 16 As shown, when compressor 101 reduces its frequency or stops, the pressures at the first, second, and third pressure points decrease, denoted as P1', P2', and P3', respectively. At this time, the internal pressure P0 of the liquid storage container remains unchanged, with P0 > P1' > P2' > P3'. Therefore, the first drain valve 115 is now closed, allowing the refrigerant in the liquid storage container 110 to be discharged.

[0250] Under different operating modes, the actions of each valve connected to the liquid storage container 110 are as follows:

[0251] Table 2 Valve body actions under each working mode of the second embodiment

[0252]

[0253] The third embodiment, such as Figures 17 to 25 As shown.

[0254] Based on the first embodiment, a second liquid inlet valve 119 and a second liquid outlet valve 117 connected to the low-pressure side pipeline are added. In addition to retaining the first embodiment of collecting liquid from the medium-pressure side for refrigeration / heating, discharging liquid from the low-pressure side for refrigeration, and discharging liquid from the high-pressure side for heating, it can also realize collecting liquid from the low-pressure side for refrigeration / heating and discharging liquid from the medium-pressure side for refrigeration.

[0255] The second end of the second liquid inlet valve 119 is connected to a position after the four-way reversing valve 103 and before the gas-liquid separator 109 in the direction of refrigeration flow, and the first end is a connecting pipe connected to the liquid storage container 110. The second end of the second liquid outlet valve 117 is connected to a position after the first end of the second liquid inlet valve 119 and before the gas-liquid separator 109 in the direction of refrigeration flow, and the first end is a connecting pipe connected to the liquid storage container 110.

[0256] For ease of understanding, we introduce the concept of a pressure point. The fourth pressure point is located at the second end of the second drain valve 117, and the pressure here is denoted as P4.

[0257] The air conditioning system of the second embodiment has a conventional cooling mode, such as Figure 17 As shown, the first inlet valve 113, the first drain valve 115, the balance valve 112, the second inlet valve 119, and the second drain valve 117 are all in the off state; and in the conventional heating mode, such as Figure 18As shown, the first liquid inlet valve 113, the first liquid outlet valve 115, the balance valve 112, the second liquid inlet valve 119 and the second liquid outlet valve 117 are all in the off state.

[0258] In addition, the air conditioning system also has the following liquid collection mode and liquid discharge mode:

[0259] A, refrigeration low-pressure side liquid collection mode: as shown in Figure 19 As shown, the second liquid inlet valve 119 is in the on state, and the pressurizing valve 111, the balance valve 112, the first liquid inlet valve 113, the first liquid outlet valve 115, and the second liquid outlet valve 117 are in the off state. After the second liquid inlet valve 119 is in the on state, the liquid refrigerant flowing back to the low-pressure side from the gas pipe valve 107 mostly enters the liquid storage container 110 through the second liquid inlet branch 5, and a small part flows through the gas-liquid separator 109 back to the low-pressure side through the first branch pipe section b. When the internal pressure of the liquid storage container 110 rises to the flow resistance of the second liquid inlet branch 5 being greater than the flow resistance of the main pipe section a, the liquid storage container 110 cannot continue to collect liquid, and the balance valve 112 can be opened to reduce the flow resistance of the second liquid inlet branch 5.

[0260] B, refrigeration medium-pressure side liquid discharge mode: as shown in Figure 20 As shown, the balance valve 112, the first liquid inlet valve 113, the first liquid outlet valve 115, and the second liquid inlet valve 119 are in the off state. First, the pressurizing valve 111 is in the on state, and after the internal pressure P0 of the liquid storage container 110 is increased to be equivalent to the first pressure point P1, the pressurizing valve 111 is in the off state; then the second liquid outlet valve 117 is in the on state, and at this time the internal pressure P0 of the liquid storage container 110 is higher than the fourth pressure point P4, and the refrigerant in the liquid storage container 110 can be discharged through the second liquid outlet valve 117 and enter the medium-pressure side of the system to participate in the circulation.

[0261] C, heating low-pressure side liquid collection mode: as shown in Figure 21 As shown, the valve body action is consistent with the refrigeration low-pressure side liquid collection mode of the third embodiment.

[0262] D, heating high-pressure side liquid discharge mode: as shown in Figure 25 As shown, the valve body action is consistent with the first heating liquid discharge and liquid collection mode of the first embodiment.

[0263] Under different operating modes, the actions of the valve bodies connected to the liquid storage container 110 are as follows:

[0264] Table 3 Valve body actions under each operating mode of the third embodiment

[0265]

[0266] The fourth embodiment is shown in Figures 26 to 31 As shown.

[0267] Based on the third embodiment, the first liquid inlet valve 113 is removed, while the rest remains unchanged. Functionally, only the functions of collecting liquid from the low-pressure side for cooling / heating, discharging liquid from the medium-pressure side for cooling, and discharging liquid from the high-pressure side for heating are retained.

[0268] The air conditioning system of the fourth embodiment has a conventional cooling mode, such as Figure 26 As shown, the first inlet valve 113, the first outlet valve 115, and the balance valve 112 are all in the off state; and in the conventional heating mode, such as Figure 27 As shown, the first inlet valve 113, the first outlet valve 115, and the balance valve 112 are all in the off state.

[0269] In addition, the air conditioning system also has the following liquid collection mode and liquid drainage mode:

[0270] A. Cooling low-pressure side liquid collection mode: (e.g.) Figure 28 As shown, the valve body operation is consistent with the liquid collection mode on the low-pressure side of the third embodiment.

[0271] B. Cooling medium-pressure side liquid drain mode: (e.g.) Figure 29 As shown, the valve body operation is consistent with the liquid discharge mode on the medium-pressure side of the third embodiment.

[0272] C. Heating low-pressure side liquid collection mode: such as Figure 30 As shown, the valve body operation is consistent with the liquid collection mode on the low-pressure side of the heating system in the third embodiment.

[0273] D. Heating high-pressure side liquid drain mode: such as Figure 31 As shown, the valve body operation is consistent with the high-pressure side liquid drainage mode of the third embodiment.

[0274] Under different operating modes, the actions of each valve connected to the liquid storage container 110 are as follows:

[0275] Table 4 Valve body actions under various operating modes in the fourth embodiment

[0276]

[0277] Fifth embodiment, such as Figures 32 to 37 As shown in the figure.

[0278] Based on the fourth embodiment, the gas-liquid separator 109 and the balance valve 112 are removed, and the first control valve 120 and the second control valve 121 are added to realize that the liquid is collected from the low-pressure side and discharged to the medium-pressure side for refrigeration, and the liquid is collected from the low-pressure side and discharged to the high-pressure side for heating.

[0279] The air conditioning system of the fifth embodiment has a conventional cooling mode, such as Figure 32 As shown, the second control valve 121 is in the on state, while the second inlet valve 119, the first drain valve 115, the second drain valve 117, and the pressure valve 111 are all in the off state; and in the conventional heating mode, such asFigure 33 As shown, the second control valve 121 is in the on state, while the first inlet valve 113, the first drain valve 115, and the balance valve 112 are all in the off state.

[0280] In addition, the air conditioning system also has the following liquid collection mode and liquid drainage mode:

[0281] A. Cooling low-pressure side liquid collection mode: (e.g.) Figure 34 As shown, the pressurization valve 111, the first drain valve 115, the second drain valve 117, the second inlet valve 119, and the second control valve 121 are in the off state. When the second inlet valve 119 and the first control valve 120 are opened, the refrigerant returning from the four-way reversing valve 103 to the low-pressure side first enters the liquid storage container 110 through the second inlet valve 119. Most of the liquid refrigerant is stored in the liquid storage container 110, and the remaining small portion of gaseous refrigerant returns to the suction side of the compressor 101.

[0282] B. Cooling medium-pressure side liquid drain mode: (e.g.) Figure 35 As shown, the first control valve 120 is in the off state, the second control valve 121 is in the on state, and the operation of the remaining valves is consistent with the liquid discharge mode of the refrigeration medium-pressure side in the fourth embodiment.

[0283] C. Heating low-pressure side liquid collection mode, such as Figure 36 As shown, the valve body operation is consistent with the liquid collection mode on the low-pressure side of the fifth embodiment.

[0284] D. Heating high-pressure side liquid drain mode, such as Figure 37 As shown, the first control valve 120 is in the off state, the second control valve 121 is in the on state, and the operation of the remaining valves is consistent with the heating high-pressure side liquid drainage mode of the fourth embodiment.

[0285] Under different operating modes, the actions of each valve connected to the liquid storage container 110 are as follows:

[0286] Table 5 Valve body actions under various operating modes in the fifth embodiment

[0287]

[0288] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. An air conditioning system, characterized in that, include: The refrigerant circulation loop is equipped with a compressor (101), an evaporator and a condenser. The discharge port of the compressor (101) and the condenser are connected by a high-pressure side pipeline, the condenser and the evaporator are connected by a medium-pressure side pipeline, and the evaporator and the suction port of the compressor (101) are connected by a low-pressure side pipeline. A liquid storage container (110) for storing refrigerant and having an inlet (A) and an outlet (B); A liquid inlet pipeline is provided with an inlet valve having an on and off state. The first end of the liquid inlet pipeline is connected to the liquid inlet (A), and the second end of the liquid inlet pipeline is connected to at least one of the low-pressure side pipeline, the medium-pressure side pipeline, and the high-pressure side pipeline. A drain pipe is provided with a drain valve having an on state and an off state. The first end of the drain pipe is connected to the outlet (B), and the second end of the drain pipe is connected to at least one of the low-pressure side pipe, the medium-pressure side pipe and the high-pressure side pipe. When the inlet valve is in the on state, the pressure at the first end of the inlet pipe is less than the pressure at the second end, so as to use the pressure difference to store the refrigerant in the refrigerant circulation loop into the storage container (110); when the drain valve is in the on state, the pressure at the first end of the drain pipe is greater than the pressure at the second end, so as to use the pressure difference to discharge the refrigerant in the storage container (110) into the refrigerant circulation loop.

2. The air conditioning system as described in claim 1, characterized in that, The liquid storage container (110) also has a pressure regulating port (C), and the air conditioning system further includes: The pressure relief branch (3) is equipped with a balance valve (112) having an on state and an off state, and the first end of the pressure relief branch (3) is connected to the pressure regulating port (C); When the balance valve (112) is in the on state, the pressure in the liquid storage container (110) is released through the pressure relief branch (3).

3. The air conditioning system as described in claim 1 or 2, characterized in that, The liquid storage container (110) also has a pressure regulating port (C), and the air conditioning system further includes: A pressurizing branch (4) is provided with a pressurizing valve (111) having an on state and an off state, and the first end of the pressurizing branch (4) is connected to the pressure regulating port (C); When the pressure valve (111) is in the on state, the high-pressure side pipeline pressurizes the liquid storage container (110).

4. The air conditioning system as described in claim 1, characterized in that, The inlet pipeline includes a first inlet branch (1), the second end of which is connected to the medium-pressure side pipeline. The inlet valve includes a first inlet valve (113) installed on the first inlet branch (1). The drain line includes a first drain branch (2), the second end of which is configured to be connected to the low-pressure side line in the cooling mode and to the high-pressure side line in the heating mode. The drain valve includes a first drain valve (115) provided on the first drain branch (2).

5. The air conditioning system as described in claim 4, characterized in that, The refrigerant circulation loop also includes a four-way reversing valve (103) and a gas-liquid separator (109). The four-way reversing valve (103) is used to switch between cooling mode and heating mode. The gas-liquid separator (109) is located on the pipeline between the four-way reversing valve (103) and the suction port of the compressor (101). The air conditioning system further includes a pressurization branch (4), the second end of the first drain branch (2) is connected to the pipeline between the four-way reversing valve (103) and the evaporator, the second end of the pressurization branch (4) is connected to the pipeline between the exhaust port of the compressor (101) and the four-way reversing valve (103); the liquid storage container (110) also has a pressure regulating port (C), the air conditioning system further includes a pressure relief branch (3), the first end of the pressure relief branch (3) is connected to the pressure regulating port (C), and the second end of the pressure relief branch (3) is connected between the inlet of the gas-liquid separator (109) and the four-way reversing valve (103).

6. The air conditioning system as described in claim 3, characterized in that, The inlet (A) and the pressure regulating port (C) are located in the upper region of the liquid storage container (110), and the outlet (B) is located in the lower region of the liquid storage container (110).

7. The air conditioning system according to any one of claims 1 to 6, characterized in that, The inlet pipeline includes a second inlet branch (5), the second end of which is connected to the low-pressure side pipeline. The inlet valve also includes a second inlet valve (119) disposed on the second inlet branch (5); and / or The drainage pipeline includes a second drainage branch (6), the second end of which is connected to the medium-pressure side pipeline. The drainage valve also includes a second drainage valve (117) installed on the second drainage branch (6).

8. The air conditioning system as described in claim 7, characterized in that, The refrigerant circulation loop also includes a four-way reversing valve (103) and a gas-liquid separator (109). The four-way reversing valve (103) is used to switch between cooling mode and heating mode. The gas-liquid separator (109) is located on the pipeline between the four-way reversing valve (103) and the suction port of the compressor (101). The second end of the second liquid inlet branch (5) is connected between the four-way reversing valve (103) and the inlet of the gas-liquid separator (109).

9. The air conditioning system as described in claim 8, characterized in that, The four-way reversing valve (103) forms a main pipeline section (a) between itself and the second end of the second liquid inlet branch (5), and a branch pipeline section (b) forms between the second end of the second liquid inlet branch (5) and the inlet of the gas-liquid separator (109). The main pipeline section (a) is connected to both the second liquid inlet branch (5) and the branch pipeline section (b). The refrigerant flow resistance of the branch pipe section (b) is greater than that of the refrigerant flow resistance of the second liquid inlet branch (5).

10. The air conditioning system as described in claim 9, characterized in that, The height of the second inlet branch (5) is lower than the length of the branch pipe section (b) near the second end of the second inlet branch (5); and / or The branch pipe section (b) is provided with a resistance-increasing part (10), which is configured to increase the refrigerant flow resistance of the branch pipe section (b).

11. The air conditioning system as described in claim 1, characterized in that, The liquid inlet pipeline includes a second liquid inlet branch (5) and a pressurization branch (4). The second end of the second liquid inlet branch (5) is connected to the low-pressure side pipeline. The liquid inlet valve includes a second liquid inlet valve (119) provided on the second liquid inlet branch (5). The pressurization branch (4) is provided with a pressurization valve (111) having an on state and an off state. The first end of the pressurization branch (4) is connected to the pressure regulating port (C) of the liquid storage container (110). The drain line includes a first drain branch (2) and / or a second drain branch (6). The second end of the first drain branch (2) is configured to be connected to the low-pressure side line in cooling mode and to be connected to the high-pressure side line in heating mode. The second end of the second drain branch (6) is connected to the medium-pressure side line. The drain valve includes a first drain valve (115) provided on the first drain branch (2) and a second drain valve (117) provided on the second drain branch (6). The refrigerant circulation loop is provided with a second control valve (121) on the pipeline section between the second end of the second liquid inlet branch (5) and the suction port of the compressor (101); the liquid storage container (110) has an outlet (D), and the air conditioning system further includes a first control valve (120), the first end of the first control valve (120) is connected to the outlet (D), and the second end of the first control valve (120) is connected to the pipeline section between the second control valve (121) and the suction port of the compressor (101).

12. A control method for an air conditioning system according to any one of claims 1 to 11, characterized in that, include: Liquid collection mode: The liquid inlet valve is turned on and the pressure at the first end of the liquid inlet pipe is less than the pressure at the second end, so that the refrigerant in the refrigerant circulation loop is stored in the liquid storage container (110). Drainage mode: When it is necessary to drain the refrigerant in the liquid storage container (110) into the refrigerant circulation loop, the drain valve is turned on and the pressure at the first end of the drain pipeline is greater than the pressure at the second end.

13. The control method as described in claim 12, characterized in that, The air conditioning system also includes a pressure relief branch (3) and a pressure boosting branch (4). The pressure relief branch (3) is equipped with a balancing valve (112), and the first end of the pressure relief branch (3) is connected to the pressure regulating port (C) of the liquid storage container (110). The pressure boosting branch (4) is equipped with a pressure boosting valve (111), and the first end of the pressure boosting branch (4) is connected to the pressure regulating port (C). The liquid inlet pipeline includes a first liquid inlet branch (1), the second end of the first liquid inlet branch (1) is connected to the medium pressure side pipeline, and the liquid inlet valve includes a first liquid inlet valve (113) provided on the first liquid inlet branch (1). The liquid collection modes include a cooling liquid collection mode and a heating liquid collection mode. In the cooling liquid collection mode and the heating liquid collection mode, the drain valve and the pressure valve (111) are both in the off state, the first liquid inlet valve (113) is in the on state, and when the pressure difference across the first liquid inlet valve (113) is less than a preset threshold, the balance valve (112) is in the on state to release the pressure in the liquid storage container (110).

14. The control method as described in claim 13, characterized in that, The drain line includes a first drain branch (2), the second end of which is configured to connect with the low-pressure side line in cooling mode and with the high-pressure side line in heating mode. The drain valve includes a first drain valve (115) provided on the first drain branch (2). The drain mode also includes a cooling drain mode and a heating drain mode. In the refrigeration drain mode, the first drain valve (115) is in the on state, and the first inlet valve (113) and the balance valve (112) are both in the off state; In the heating and draining mode, the first inlet valve (113) is first turned on. When the pressure in the liquid storage container (110) reaches the pressure at the second end of the first inlet branch (1), the first inlet valve (113) is turned off. Then, the compressor (101) is reduced in frequency or stopped. At this time, the first drain valve (115) is turned on.

15. The control method as described in claim 13, characterized in that, The air conditioning system also includes a pressurization branch (4), on which a first end of the pressurization branch (4) is connected to the pressure regulating port (C), and a pressurization valve (111) is provided on the pressurization branch (4); the drain pipe includes a first drain branch (2), the second end of the first drain branch (2) is configured to be connected to the low-pressure side pipe in the cooling mode and to be connected to the high-pressure side pipe in the heating mode, and the drain valve includes a first drain valve (115) provided on the first drain branch (2). The drainage modes include: a first cooling drainage mode, a second cooling drainage mode, a first heating drainage mode, and a second heating drainage mode; wherein... In the first refrigeration drain mode, the first drain valve (115) is turned on. When the internal pressure of the liquid storage container (110) drops to the same level as the low-pressure side pipeline, the pressure valve (111) is turned on, and the first liquid inlet valve (113) and the balance valve (112) are both turned off. In the second refrigeration drain mode, the balance valve (112) is turned on, and the first liquid inlet valve (113), the first liquid drain valve (115) and the pressure valve (111) are all turned off. In the first heating and draining mode, the pressure valve (111) is turned on so that the pressure inside the liquid storage container (110) rises to the pressure at the second end of the pressure branch (4), and the first drain valve (115) is turned on. In the second heating and draining mode, the pressure valve (111) is first turned on. When the pressure inside the liquid storage container (110) rises to the pressure at the second end of the pressure branch (4), the pressure valve (111) is switched to the off state. Then, the compressor (101) is reduced in frequency or stopped. At this time, the first drain valve (115) is turned on.

16. The control method as described in claim 15, characterized in that, The liquid inlet pipeline includes a second liquid inlet branch (5), the second end of which is connected to the low-pressure side pipeline. The liquid inlet valve also includes a second liquid inlet valve (119) provided on the second liquid inlet branch (5). The liquid outlet pipeline includes a second liquid outlet branch (6), the second end of which is connected to the medium-pressure side pipeline. The liquid outlet valve also includes a second liquid outlet valve (117) provided on the second liquid outlet branch (6). A branch pipeline section (b) is formed between the second end of the second liquid inlet branch (5) and the inlet of the gas-liquid separator (109). The liquid collection mode further includes: a cooling low-pressure side liquid collection mode and a heating low-pressure side liquid collection mode. In the cooling low-pressure side liquid collection mode and the heating low-pressure side liquid collection mode, the second liquid inlet valve (119) is in the on state. When the pressure in the liquid storage container (110) rises to the point that the refrigerant flow resistance of the second liquid inlet branch (5) is greater than that of the branch pipe section (b), the balancing valve (112) is opened; and / or The draining mode also includes: a refrigeration medium-pressure side draining mode. In the refrigeration medium-pressure side draining mode, the pressure valve (111) is first turned on. When the pressure in the liquid storage container (110) rises to the pressure at the second end of the pressure branch (4), the pressure valve (111) is switched to the off state. Then, the second draining valve (117) is opened.

17. The control method as described in claim 12, characterized in that, The liquid inlet pipeline includes a second liquid inlet branch (5) and a pressurization branch (4). The second end of the second liquid inlet branch (5) is connected to the low-pressure side pipeline. The liquid inlet valve includes a second liquid inlet valve (119) provided on the second liquid inlet branch (5). The pressurization branch (4) is provided with a pressurization valve (111). The first end of the pressurization branch (4) is connected to the pressure regulating port (C) of the liquid storage container (110). The drain line includes a first drain branch (2) and a second drain branch (6). The second end of the first drain branch (2) is configured to connect with the low-pressure side line in cooling mode and with the high-pressure side line in heating mode. The second end of the second drain branch (6) is connected with the medium-pressure side line. The drain valve includes a first drain valve (115) provided on the first drain branch (2) and a second drain valve (117) provided on the second drain branch (6). The refrigerant circulation loop is provided with a second control valve (121) on the pipeline section between the second end of the second liquid inlet branch (5) and the suction port of the compressor (101); the liquid storage container (110) has a vent, and the air conditioning system further includes a first control valve (120), the first end of the first control valve (120) is connected to the vent, and the second end of the first control valve (120) is connected to the pipeline section between the second control valve (121) and the suction port of the compressor (101); The liquid collection mode includes a cooling low-pressure side liquid collection mode and a heating low-pressure side liquid collection mode. In the cooling low-pressure side liquid collection mode and the heating low-pressure side liquid collection mode, the second liquid inlet valve (119) and the first control valve (120) are in the on state.

18. The control method as described in claim 17, characterized in that, The drainage modes include a medium-pressure side drainage mode for cooling and a high-pressure side drainage mode for heating. In the medium-pressure side drain mode of the refrigeration, the first control valve (120) is in the off state and the second control valve (121) is in the on state. Then, the pressure valve (111) is in the on state to increase the pressure in the liquid storage container (110) and the second drain valve (117) is in the on state. In the high-pressure side drain mode of heating, the first control valve (120) is in the off state and the second control valve (121) is in the on state. Then, the pressure valve (111) is in the on state to increase the pressure inside the liquid storage container (110) and the first drain valve (115) is in the on state.

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