Air conditioning system and control method

Abstract

The application provides an air conditioning system and a control method, the air conditioning system comprising: a compressor and a gas-liquid separator; a heat exchange structure, the heat exchange structure having a first heat exchange channel and a second heat exchange channel for heat exchange, an inlet of the first heat exchange channel being selectively communicated with or disconnected from a discharge port of the compressor, an outlet of the first heat exchange channel being communicated with an inlet of the gas-liquid separator, an inlet of the second heat exchange channel being selectively communicated with or disconnected from a bottom of the gas-liquid separator, an outlet of the second heat exchange channel being communicated with an air inlet of the compressor, and the first heat exchange channel being used for heating the second heat exchange channel. Through the technical scheme provided by the application, the technical problem that the compressor of the air conditioning system in the prior art is prone to liquid strike can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioning systems, in particular to an air conditioning system and a control method. BACKGROUND

[0002] At present, the compressor of an air conditioning system is easily damaged under liquid strike, so most air conditioning systems are provided with a gas-liquid separator to separate the liquid refrigerant from the gaseous refrigerant, so as to avoid the liquid strike caused by the liquid refrigerant entering the compressor.

[0003] However, the separation efficiency of the conventional gas-liquid separator is low, especially at low temperature, which will make the separation efficiency even lower. In order to reduce the cost of the air conditioning system and improve the reliability of the air conditioning system, the volume of the general gas-liquid separator is limited, which further aggravates the risk of liquid return. Especially when the air conditioning system is running in a super-low temperature outdoor environment, a large amount of liquid refrigerant accumulates in the gas-liquid separator. Due to the low ambient temperature, the refrigerant of the air conditioning system is difficult to circulate in a short time, which causes the air conditioning system to have a low exhaust gas superheat degree for a long time after the compressor starts. At this time, not only is liquid strike likely to occur, but also poor lubrication of the lubricating oil is caused, which leads to damage of the compressor. In addition, when the air conditioning system is running for a long time, the outdoor heat exchanger will continuously frost, which will further aggravate the accumulation of liquid refrigerant in the gas-liquid separator, and thus cause a large amount of liquid return to impact the compressor. SUMMARY

[0004] The main purpose of the present application is to provide an air conditioning system and a control method to solve the technical problem of the compressor of the air conditioning system in the prior art being prone to liquid strike.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, an air conditioning system is provided, comprising:

[0006] a compressor and a gas-liquid separator;

[0007] a heat exchange structure, the heat exchange structure having a first heat exchange passage and a second heat exchange passage for heat exchange, an inlet of the first heat exchange passage being selectively communicated with or disconnected from an exhaust port of the compressor, an outlet of the first heat exchange passage being communicated with an inlet of the gas-liquid separator, an inlet of the second heat exchange passage being selectively communicated with or disconnected from a bottom of the gas-liquid separator, an outlet of the second heat exchange passage being communicated with an air inlet of the compressor, the first heat exchange passage being used for heating the second heat exchange passage.

[0008] Further, the air conditioning system further comprises:

[0009] a flow regulating valve, arranged on a communication pipeline between the inlet of the second heat exchange passage and the bottom of the gas-liquid separator, the flow opening degree of the flow regulating valve being adjustably set; and / or,

[0010] The switch valve is arranged on a connecting pipeline between the inlet of the first heat exchange channel and the exhaust port of the compressor.

[0011] Further, the air conditioning system further comprises:

[0012] The electronic expansion valve is arranged on a connecting pipeline between the inlet of the second heat exchange channel and the bottom of the gas-liquid separator, and the flow opening degree of the electronic expansion valve is adjustably arranged.

[0013] Further, the air conditioning system further comprises:

[0014] The oil separator is arranged on a connecting pipeline between the exhaust port of the compressor and the gas outlet of the oil separator.

[0015] Further, the air conditioning system further comprises:

[0016] The first temperature detection member is arranged at the exhaust port of the compressor to detect the temperature of the medium at the exhaust port of the compressor; and / or,

[0017] The second temperature detection member is arranged at the gaseous refrigerant outlet of the gas-liquid separator to detect the temperature of the medium at the gaseous refrigerant outlet of the gas-liquid separator; and / or,

[0018] The third temperature detection member is arranged at the outlet of the second heat exchange channel to detect the temperature of the medium at the outlet of the second heat exchange channel.

[0019] Further, the air conditioning system further comprises:

[0020] The first pressure sensor is arranged at the exhaust port of the compressor to detect the exhaust-side pressure value at the exhaust port of the compressor; and / or,

[0021] The second pressure sensor is arranged at the inlet of the gas-liquid separator to detect the suction-side pressure value at the inlet of the gas-liquid separator.

[0022] According to another aspect of the present application, a control method is provided, which is suitable for the air conditioning system provided above, and the control method comprises:

[0023] Obtaining the suction superheat value Ts of the air conditioning system;

[0024] Adjusting the working condition of the heat exchange structure of the air conditioning system according to the size of the suction superheat value Ts;

[0025] Wherein, Ts = Tx-Tps, Tx is the temperature value at the gaseous refrigerant outlet of the gas-liquid separator of the air conditioning system, and Tps is the saturation temperature value corresponding to the exhaust-side pressure value.

[0026] Further, the heat exchange structure of the air conditioning system is adjusted according to the size of the suction superheat value Ts, including:

[0027] When the suction superheat value Ts is greater than the first preset temperature value, the inlet of the first heat exchange channel of the heat exchange structure is disconnected from the exhaust port of the compressor of the air conditioning system, and the inlet of the second heat exchange channel of the heat exchange structure is disconnected from the bottom of the gas-liquid separator of the air conditioning system.

[0028] When the suction superheat value Ts is less than or equal to the first preset temperature value, the inlet of the first heat exchange channel of the heat exchange structure is connected to the exhaust port of the compressor of the air conditioning system, and the inlet of the second heat exchange channel of the heat exchange structure is connected to the bottom of the gas-liquid separator of the air conditioning system.

[0029] Further, the air conditioning system is provided above; when the suction superheat value Ts is less than or equal to the first preset temperature value, the control method further includes:

[0030] Obtaining a reheating superheat value Tz of the air conditioning system;

[0031] Adjusting the opening degree of the electronic expansion valve of the air conditioning system according to the size of the reheating superheat value Tz of the air conditioning system;

[0032] Wherein, Tz=Tm-Tps, Tm is the medium temperature value at the outlet of the second heat exchange channel.

[0033] Further, the opening degree of the electronic expansion valve of the air conditioning system is adjusted according to the size of the reheating superheat Tz of the air conditioning system, including:

[0034] When the reheating superheat value Tz is less than the second preset temperature value, the opening degree of the electronic expansion valve is controlled to decrease;

[0035] When the reheating superheat value Tz is greater than or equal to the second preset temperature value and less than or equal to the third preset temperature value, the opening degree of the electronic expansion valve is controlled to remain unchanged;

[0036] When the reheating superheat value Tz is greater than the third preset temperature value, the opening degree of the electronic expansion valve is controlled to increase.

[0037] Further, the opening degree of the electronic expansion valve is controlled to decrease, including:

[0038] The opening degree of the electronic expansion valve is controlled to decrease at a preset opening decrease rate until the reheating superheat value is greater than or equal to the second preset temperature, or until the minimum opening degree of the electronic expansion valve is reached; and / or,

[0039] The opening degree of the electronic expansion valve is controlled to increase, including:

[0040] The opening of the electronic expansion valve is increased at a second preset opening increasing rate until the reheat superheat is less than or equal to a third preset temperature, or until the maximum opening of the electronic expansion valve is reached.

[0041] When the first heat exchange passage is communicated with the exhaust port of the compressor and the second heat exchange passage is communicated with the bottom of the gas-liquid separator, the high-temperature and high-pressure gaseous refrigerant at the exhaust port of the compressor is introduced into the first heat exchange passage, the liquid refrigerant at the bottom of the gas-liquid separator is introduced into the second heat exchange passage, and the liquid refrigerant in the second heat exchange passage is heated by the high-temperature and high-pressure gaseous refrigerant in the first heat exchange passage to be heated into gaseous refrigerant and then introduced into the air inlet of the compressor. In addition, the gaseous refrigerant has a high temperature and can heat the refrigerant flowing from the gaseous refrigerant outlet of the gas-liquid separator to the air inlet of the compressor, thereby reducing the amount of liquid refrigerant entering the air inlet of the compressor and reducing the phenomenon of liquid strike of the compressor of the air conditioning system. BRIEF DESCRIPTION OF DRAWINGS

[0042] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, illustrate the preferred embodiments of the application and assist in the explanation of the application. In the drawings, the same reference numbers represent the same elements throughout the several views of the drawings:

[0043] Figure 1 A structural schematic diagram of an air conditioning system according to an embodiment of the application is shown;

[0044] Figure 2 A flow chart of a control method according to an embodiment of the application is shown.

[0045] In the above drawings, the following reference signs are used:

[0046] 10, compressor; 20, gas-liquid separator;

[0047] 30, heat exchange structure; 31, first heat exchange passage; 32, second heat exchange passage;

[0048] 40, flow regulating valve; 50, on-off valve; 60, oil separator; 70, first temperature detecting member; 80, second temperature detecting member; 90, third temperature detecting member; 100, first pressure sensor; 110, second pressure sensor; 120, outdoor heat exchanger; 130, subcooler; 140, indoor unit; 150, four-way valve; 160, gas inlet temperature sensing bulb; 170, heating electronic expansion valve; 180, subcooler electromagnetic valve. DETAILED DESCRIPTION

[0049] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other in the case of no conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0050] As shown in Figure 1 The embodiment one of the present application provides an air conditioning system, which comprises a compressor 10, a gas-liquid separator 20 and a heat exchange structure 30, the heat exchange structure 30 has a first heat exchange passage 31 and a second heat exchange passage 32 for heat exchange, the inlet of the first heat exchange passage 31 is selectively communicated with or disconnected from the exhaust port of the compressor 10, the outlet of the first heat exchange passage 31 is communicated with the inlet of the gas-liquid separator 20, the inlet of the second heat exchange passage 32 is selectively communicated with or disconnected from the bottom of the gas-liquid separator 20, the outlet of the second heat exchange passage 32 is communicated with the air inlet of the compressor 10, and the first heat exchange passage 31 is used for heating the second heat exchange passage 32.

[0051] When the inlet of the first heat exchange passage 31 is communicated with the exhaust port of the compressor 10 and the inlet of the second heat exchange passage 32 is communicated with the bottom of the gas-liquid separator 20, the high-temperature and high-pressure gaseous refrigerant at the exhaust port of the compressor 10 is introduced into the first heat exchange passage 31, the liquid refrigerant at the bottom of the gas-liquid separator 20 is introduced into the inlet of the second heat exchange passage 32, and the high-temperature and high-pressure gaseous refrigerant in the first heat exchange passage 31 is used to heat the liquid refrigerant in the second heat exchange passage 32, so that the liquid refrigerant is heated into gaseous refrigerant and then sent to the air inlet of the compressor 10. In addition, the high-temperature gaseous refrigerant also heats the refrigerant flowing from the gaseous refrigerant outlet of the gas-liquid separator 20 to the air inlet of the compressor 10, thereby reducing the amount of liquid refrigerant entering the air inlet of the compressor 10 as a whole, reducing the phenomenon of liquid strike of the compressor 10 of the air conditioning system, improving the operation capacity of the air conditioning system and the use comfort of the air conditioning system, and improving the reliability of the air conditioning system. Therefore, through the air conditioning system provided by the embodiment, the technical problem of the compressor 10 of the air conditioning system in the prior art being prone to liquid strike can be solved.

[0052] Specifically, the first heat exchange passage 31 and the second heat exchange passage 32 are arranged separately. The first heat exchange passage 31 corresponds to a high-pressure gas path, the second heat exchange passage 32 corresponds to a low-pressure liquid path, and the high-pressure gas path and the low-pressure liquid path exchange heat in the heat exchange structure 30.

[0053] Specifically, the air conditioning system in this embodiment also includes a flow regulating valve 40, which is installed on the connecting pipe between the inlet of the second heat exchange channel 32 and the bottom of the gas-liquid separator 20. The flow opening of the flow regulating valve 40 is adjustable. This allows for convenient adjustment of the amount of liquid refrigerant flowing into the first heat exchange channel 31 via the flow regulating valve 40, thereby facilitating control of the heating level of the second heat exchange channel 32 and the temperature adjustment of the refrigerant flowing out of the second heat exchange channel 32. This achieves flexible and precise control of refrigerant temperature heating, further improving the operational stability, comfort, and energy efficiency of the air conditioning system. Specifically, the flow regulating valve 40 has an open state and a closed state. When the flow regulating valve 40 is in the closed state, the inlet of the second heat exchange channel 32 is disconnected from the bottom of the gas-liquid separator 20, meaning the flow rate is zero. When the flow regulating valve 40 is in the open state, the inlet of the second heat exchange channel 32 is connected to the bottom of the gas-liquid separator 20, meaning the flow rate is not zero. Specifically, when the flow regulating valve 40 is in the open state, it has a minimum opening degree, which can be understood as a preset opening degree greater than zero.

[0054] Specifically, the flow regulating valve 40 can be an electronic expansion valve, an electric ball valve, or a solenoid valve, etc.

[0055] Preferably, the flow regulating valve 40 is an electronic expansion valve. In this way, the electronic expansion valve not only has the function of precisely adjusting the flow rate, but also has the function of throttling and reducing pressure, so that the refrigerant after pressure reduction can absorb less heat to change the temperature of the refrigerant in the second heat exchange channel 32, thereby improving the heating effect of the refrigerant in the second heat exchange channel 32 and also achieving energy saving effect.

[0056] Specifically, the air conditioning system in this embodiment also includes a switching valve 50, which is installed on the connecting pipe between the inlet of the first heat exchange channel 31 and the exhaust port of the compressor 10. This allows for flexible control of the connection or disconnection between the inlet of the first heat exchange channel 31 and the exhaust port of the compressor 10 according to actual needs, facilitating operation.

[0057] Specifically, the switching valve 50 can also be called a bypass valve.

[0058] In this embodiment, the air conditioning system also includes an electronic expansion valve, which is installed on the connecting pipe between the inlet of the second heat exchange channel 32 and the bottom of the gas-liquid separator 20. The flow opening of the electronic expansion valve can be adjusted.

[0059] Specifically, the air conditioning system further comprises an oil separator 60, an inlet of the oil separator 60 being communicated with the exhaust port of the compressor 10, and an inlet of the first heat exchange channel 31 being communicated with a separated gas port of the oil separator 60. By adopting the structure, the content of the lubricating oil mixed in the refrigerant can be reduced, so that the gaseous refrigerant can enter the inlet of the first heat exchange channel 31 as much as possible, the lubricating oil entering the inlet of the first heat exchange channel 31 can be reduced as much as possible, and the content of the lubricating oil mixed in the refrigerant in the circulation process can be reduced better, the liquid knock caused by the content of the lubricating oil entering the compressor 10 for compression can be better reduced, and the liquid knock of the compressor 10 can be better reduced.

[0060] Specifically, the air conditioning system further comprises a first temperature detecting member 70, which is arranged at the exhaust port of the compressor 10 to detect the temperature of the medium at the exhaust port of the compressor 10. In this way, the superheat of the exhaust gas can be obtained according to the difference between the temperature detected by the first temperature detecting member 70 and the evaporation saturation temperature. Specifically, the temperature detected by the first temperature detecting member 70 is Tp, the evaporation saturation temperature is Tpd, and the superheat of the exhaust gas is Tg, Tg = Tp - Tpd.

[0061] Specifically, the air conditioning system further comprises a second temperature detecting member 80, which is arranged at the gaseous refrigerant outlet of the gas-liquid separator 20 to detect the temperature of the medium at the gaseous refrigerant outlet of the gas-liquid separator 20. In this way, the superheat of the suction gas can be obtained according to the difference between the temperature detected by the second temperature detecting member 80 and the condensation saturation temperature. Specifically, the temperature detected by the second temperature detecting member 80 is Tx, which can also be understood as the detected temperature of the suction pipe. The condensation saturation temperature is Tps, and the superheat value of the suction gas is Ts, Ts = Tx - Tps.

[0062] Specifically, the air conditioning system further comprises a third temperature detecting member 90, which is arranged at the outlet of the second heat exchange channel 32 to detect the temperature of the medium at the outlet of the second heat exchange channel 32. In this way, the reheating superheat can be obtained according to the difference between the temperature detected by the third temperature detecting member 90 and the condensation saturation temperature. Specifically, the temperature detected by the third temperature detecting member 90 is Tm, and the reheating superheat is Tz, Tz = Tm - Tps.

[0063] Specifically, the superheat of the exhaust gas is Tg, Tg = Tp - Tpd. In the embodiment, a fourth temperature detecting member is further arranged, which is used to detect the outdoor environment temperature Tenv, and the corresponding unit is ℃.

[0064] Specifically, the first temperature detecting member 70, the second temperature detecting member 80 and the third temperature detecting member 90 can all be temperature sensing bags.

[0065] In the embodiment, the air conditioning system further comprises a first pressure sensor 100 arranged at the exhaust port of the compressor 10 to detect the exhaust-side pressure value at the exhaust port of the compressor 10. With such a structure, the exhaust-side pressure value corresponding to the saturation temperature, i.e. the condensing pressure corresponding to the saturation temperature value, i.e. the condensing saturation temperature, can be determined according to the exhaust-side pressure value.

[0066] In the embodiment, the air conditioning system further comprises a second pressure sensor 110 arranged at the inlet of the gas-liquid separator 20 to detect the suction-side pressure value at the inlet of the gas-liquid separator 20. With such a structure, the suction-side pressure value corresponding to the saturation temperature, i.e. the evaporating pressure corresponding to the saturation temperature value, i.e. the evaporating saturation temperature, can be determined according to the suction-side pressure value.

[0067] Specifically, the pressure values detected by the first pressure sensor 100 and the second pressure sensor 110 are transmitted to the main control board of the air conditioning system, and the temperature value detected by the temperature sensing bag is transmitted to the main control board.

[0068] It should be noted that the air conditioning system in the embodiment is based on the conventional air conditioning system in the prior art, and the bypass branch is added and the heat exchange structure 30 is installed on the bypass branch. Thus, the normal operation function of the conventional air conditioning system does not need to be changed, and the heating function of the refrigerant can be added on the basis of the normal operation of the air conditioning system, so as to reduce the content of the liquid refrigerant entering the compressor 10 and better reduce the liquid knock of the compressor 10. Specifically, the bypass branch comprises two branches, one branch is provided with the first heat exchange channel 31 and the flow regulating valve 40, and the other branch is provided with the second heat exchange channel 32 and the on-off valve 50.

[0069] Specifically, the air conditioning system in the embodiment further comprises an outdoor heat exchanger 120, an overcooling device 130, an indoor unit 140, a four-way valve 150, a gas-liquid separation inlet temperature sensing bag 160, a heating electronic expansion valve 170, and an overcooling device electromagnetic valve 180. Specifically, the indoor unit 140 is connected with the outdoor heat exchanger 120 through a first pipeline, and the first pipeline is a gas pipeline. The indoor unit 140 is connected with the overcooling device 130 through a second pipeline, and the second pipeline is a liquid pipeline.

[0070] The embodiment two of the present application provides a control method, which is suitable for the air conditioning system provided by the above-mentioned embodiment, and the control method comprises the following steps: obtaining a suction superheat value Ts of the air conditioning system; adjusting the working condition of a heat exchange structure 30 of the air conditioning system according to the size of the suction superheat value Ts; wherein Ts = Tx-Tps, Tx is a temperature value at the gaseous refrigerant outlet of a gas-liquid separator 20 of the air conditioning system, and Tps is a saturated temperature value corresponding to the exhaust side pressure value.

[0071] By using the method, the working condition of the heat exchange structure 30 can be adjusted according to the size of the suction superheat value, so as to determine whether to control the heat exchange structure 30 to perform heating operation or to be disconnected or to perform heating degree adjustment, thereby flexibly realizing the adjustment of the heating temperature of the refrigerant in the second heat exchange channel 32, and facilitating the adjustment of the temperature of the refrigerant entering the air inlet of the compressor 10, and further reducing the content of the liquid refrigerant in the refrigerant entering the air inlet of the compressor 10, thereby reducing the liquid compression of the compressor 10.

[0072] Specifically, the adjustment of the working condition of the heat exchange structure 30 of the air conditioning system according to the size of the suction superheat value Ts comprises the following steps: when the suction superheat value Ts is greater than a first preset temperature value, the inlet of the first heat exchange channel 31 of the heat exchange structure 30 is disconnected from the exhaust port of the compressor 10 of the air conditioning system, and the inlet of the second heat exchange channel 32 of the heat exchange structure 30 is disconnected from the bottom of the gas-liquid separator 20 of the air conditioning system; when the suction superheat value Ts is less than or equal to the first preset temperature value, the inlet of the first heat exchange channel 31 of the heat exchange structure 30 is connected to the exhaust port of the compressor 10 of the air conditioning system, and the inlet of the second heat exchange channel 32 of the heat exchange structure 30 is connected to the bottom of the gas-liquid separator 20 of the air conditioning system. In this way, when Ts is large, it can be determined that the refrigerant does not need to be heated, that is, the heat exchange structure 30 is in a stopped working state, and the air conditioning system operates normally; when Ts is small, the heating structure can be put into operation in time to heat the refrigerant in the second heat exchange channel 32 by the refrigerant in the first heat exchange channel 31.

[0073] Specifically, the medium temperature can be understood as the refrigerant temperature, and the first preset temperature value can be 2℃.

[0074] In the embodiment, the air conditioning system is the air conditioning system provided above; when the suction superheat Ts is less than or equal to the first preset temperature value, the control method further comprises: obtaining the reheating superheat Tz of the air conditioning system; and adjusting the opening of the electronic expansion valve of the air conditioning system according to the size of the reheating superheat Tz of the air conditioning system; wherein Tz=Tm-Tps, and Tm is the medium temperature value at the outlet of the second heat exchange channel 32. In this way, the heating condition of the heat exchange structure 30 can be conveniently controlled according to the medium temperature value at the outlet of the second heat exchange channel 32, thereby further improving the accuracy and flexibility of the control, avoiding energy waste caused by overheating, and avoiding the case that the heating is too small to meet the effective liquid drop reduction.

[0075] Specifically, the opening of the electronic expansion valve of the air conditioning system is adjusted according to the size of the reheating superheat Tz of the air conditioning system, including: when the reheating superheat Tz is less than the second preset temperature value, the opening of the electronic expansion valve is controlled to decrease; when the reheating superheat Tz is greater than or equal to the second preset temperature value and less than or equal to the third preset temperature value, the opening of the electronic expansion valve is controlled to remain unchanged; and when the reheating superheat Tz is greater than the third preset temperature value, the opening of the electronic expansion valve is controlled to increase. In this way, the opening of the electronic expansion valve can be adaptively and effectively controlled flexibly according to the size of the reheating superheat, so that the temperature of the refrigerant in the second heat exchange channel 32 of the heat exchange structure 30 can be better regulated.

[0076] Specifically, the second preset temperature value can be 2℃, and the third preset temperature value can be 10℃.

[0077] In the embodiment, the opening of the electronic expansion valve is controlled to decrease, including: the opening of the electronic expansion valve is controlled to decrease at a preset opening decrease rate until the reheating superheat is greater than or equal to the second preset temperature, or until the minimum opening of the electronic expansion valve is reached. In this way, the flow rate can be flexibly and accurately regulated by the electronic expansion valve, the temperature of the refrigerant in the second heat exchange channel 32 can be quickly regulated, and the reheating superheat is prevented from being too small.

[0078] Specifically, the preset opening decrease rate is 10 PLS per 20s, and the minimum opening is 30 PLS.

[0079] Specifically, the opening of the electronic expansion valve is controlled to increase, including: the opening of the electronic expansion valve is controlled to increase at a second preset opening increase rate until the reheating superheat is less than or equal to the third preset temperature, or until the maximum opening of the electronic expansion valve is reached. In this way, the flow rate can be flexibly and accurately regulated by the electronic expansion valve, the temperature of the refrigerant in the second heat exchange channel 32 can be quickly regulated, and the reheating superheat is prevented from being too large.

[0080] Specifically, the preset opening degree increasing rate is 10 PLS per 20 s, and the maximum opening degree is 480 PLS.

[0081] As shown in FIG. 1, the control method of the embodiment includes the following steps: Figure 2

[0082] When the air conditioning system is in the non-liquid return state:

[0083] When the air conditioning system is in the non-liquid return state: Figure 2 When the air conditioning system is in the non-liquid return state: Figure 2 When the air conditioning system is in the non-liquid return state:

[0084] When the air conditioning system is in the liquid return state:

[0085] When the air conditioning system is in the liquid return state:

[0086] ​From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects: improving the problem of rapid heating of the liquid return portion refrigerant, shortening the heating time, improving the operation capacity and air conditioning comfort of the air conditioning system, prolonging the heating operation time, and improving the reliability of the air conditioning system; improving the problem that the suction refrigerant state of the compressor cannot be fully matched with the operating state of the compressor, the return gas temperature and the return gas amount are not matched, improving the operation stability and energy saving, and avoiding secondary liquid knock.

[0087] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0088] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples are not intended to limit the scope of the present application, unless otherwise specifically stated. It will be further understood that the dimensions of the various parts shown in the drawings are not drawn to scale for the sake of convenience. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the specification where appropriate. In all examples shown and discussed herein, any specific value should be interpreted as merely an example, and not as a limitation. Thus, other examples of the example embodiments can have different values. It should be noted that like reference numerals and letters refer to like items in the following drawings, and thus, once an item is defined in one drawing, it need not be discussed further in subsequent drawings.

[0089] In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, perpendicular, horizontal", and "top, bottom" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate and imply that the indicated device or element must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the scope of protection of the present application; the orientation words "inner, outer" refer to the inner and outer relative to the contour of the parts themselves.

[0090] For purposes of the description hereinafter, the terms "upper", "lower", "right", "left", "rear", "front", "vertical" and "horizontal" as can be perceived herein relative to the accompanying drawings refer to the orientation of the components being described. However, it is to be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device described herein relative to the other device or structure is inverted, then a spatially relative term such as "above" can be interpreted as meaning "below" or "below" can be interpreted as meaning "above". The device can also be oriented in other ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. The devices can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0091] In addition, it should be pointed out that the use of "first", "second" and the like words to limit parts, only for the convenience of the corresponding parts for the distinction, such as no other declaration, the above words have no special meaning, therefore can not be understood as limiting the scope of the present application.

[0092] The above only the preferred embodiments of the present application, and is not intended to limit the present application, for those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application, should be included in the scope of protection of the present application.

Claims

1. A control method of an air conditioning system, characterized by, The air conditioning system comprises: a compressor (10) and a gas-liquid separator (20); a heat exchange structure (30) having a first heat exchange passage (31) and a second heat exchange passage (32) for heat exchange, an inlet of the first heat exchange passage (31) being selectively communicated with or disconnected from a discharge port of the compressor (10), an outlet of the first heat exchange passage (31) being communicated with an inlet of the gas-liquid separator (20), an inlet of the second heat exchange passage (32) being selectively communicated with or disconnected from a bottom of the gas-liquid separator (20), an outlet of the second heat exchange passage (32) being communicated with an inlet of the compressor (10), the first heat exchange passage (31) being used for heating the second heat exchange passage (32); an electronic expansion valve arranged on a communication pipeline between the inlet of the second heat exchange passage (32) and the bottom of the gas-liquid separator (20), an opening degree of the electronic expansion valve being adjustably set; a control method of the air conditioning system comprises: obtaining a suction superheat value Ts of the air conditioning system; Ts = Tx-Tps, Tx being a temperature value at a gaseous refrigerant outlet of a gas-liquid separator of the air conditioning system, and Tps being a saturated temperature value corresponding to a discharge side pressure value; when the suction superheat value Ts is greater than a first preset temperature value, controlling the inlet of the first heat exchange passage of the heat exchange structure to be disconnected from the discharge port of the compressor of the air conditioning system and the inlet of the second heat exchange passage of the heat exchange structure to be disconnected from the bottom of the gas-liquid separator of the air conditioning system; when the suction superheat value Ts is less than or equal to the first preset temperature value, controlling the inlet of the first heat exchange passage of the heat exchange structure to be communicated with the discharge port of the compressor of the air conditioning system and the inlet of the second heat exchange passage of the heat exchange structure to be communicated with the bottom of the gas-liquid separator of the air conditioning system; obtaining a reheating superheat value Tz of the air conditioning system; when the reheating superheat value Tz is less than a second preset temperature value, controlling the opening degree of the electronic expansion valve to be reduced; when the reheating superheat value Tz is greater than or equal to the second preset temperature value and less than or equal to a third preset temperature value, controlling the opening degree of the electronic expansion valve to be maintained unchanged; when the reheating superheat value Tz is greater than the third preset temperature value, controlling the opening degree of the electronic expansion valve to be increased; wherein Tz = Tm-Tps, and Tm is a medium temperature value at an outlet of the second heat exchange passage.

2. The control method of the air conditioning system according to claim 1, characterized by, The air conditioning system further comprises: a flow regulating valve (40) arranged on a communication pipeline between the inlet of the second heat exchange passage (32) and the bottom of the gas-liquid separator (20), an opening degree of the flow regulating valve (40) being adjustably set; and / or, a switch valve (50) arranged on a connection pipeline between the inlet of the first heat exchange passage (31) and the discharge port of the compressor (10).

3. The control method of the air conditioning system according to claim 1, characterized by, The air conditioning system further comprises: An oil separator (60) is provided, an inlet of the oil separator (60) being communicated with an exhaust port of the compressor (10), and an inlet of the first heat exchange passage (31) being communicated with a separated gas port of the oil separator (60).

4. The control method of the air conditioning system according to claim 1, characterized by, The air conditioning system further comprises: a first temperature detecting member (70) arranged at the exhaust port of the compressor (10) to detect a medium temperature at the exhaust port of the compressor (10); and / or a second temperature detecting member (80) arranged at the gaseous refrigerant outlet of the gas-liquid separator (20) to detect a medium temperature at the gaseous refrigerant outlet of the gas-liquid separator (20); and / or a third temperature detecting member (90) arranged at the outlet of the second heat exchange passage (32) to detect a medium temperature at the outlet of the second heat exchange passage (32).

5. The control method of an air conditioning system according to claim 1, wherein The air conditioning system further comprises: a first pressure sensor (100) arranged at the exhaust port of the compressor (10) to detect an exhaust side pressure value at the exhaust port of the compressor (10); and / or a second pressure sensor (110) arranged at the inlet of the gas-liquid separator (20) to detect a suction side pressure value at the inlet of the gas-liquid separator (20).

6. The control method of the air conditioning system according to claim 1, wherein the control of the opening degree of the electronic expansion valve to decrease comprises: controlling the opening degree of the electronic expansion valve to decrease at a preset opening degree decrease rate until the reheating superheat value is greater than or equal to the second preset temperature, or until a minimum opening degree of the electronic expansion valve is reached; and / or the control of the opening degree of the electronic expansion valve to increase comprises: controlling the opening degree of the electronic expansion valve to increase at a second preset opening degree increase rate until the reheating superheat value is less than or equal to the third preset temperature, or until a maximum opening degree of the electronic expansion valve is reached.

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