Air conditioning system and control method thereof

Abstract

The application provides an air conditioning system and a control method thereof. The system comprises an evaporator, a condenser, a throttling element and a compressor. The air conditioning system further comprises a first liquid storage tank, a first pipeline, a second pipeline and a cooling branch capable of controllable cut-off communication. The first pipeline is in controllable cut-off communication with the top of the first liquid storage tank, so as to be capable of introducing the refrigerant with a higher temperature in the air conditioning system into the first liquid storage tank. The bottom of the first liquid storage tank is in communication with the outlet of the condenser through the second pipeline. The cooling branch has a heat exchange structure. The refrigerant with a lower temperature in the air conditioning system flowing in the cooling branch can cool the refrigerant in the first liquid storage tank at the heat exchange structure. The application utilizes the cold or heat generated by the air conditioning system itself to change the refrigerant circulation amount, so as to ensure that the refrigerant circulation amount in the air conditioning system matches the specific operation condition of the air conditioning system, and prevent the phenomenon that the refrigerant circulation amount is too large to cause liquid accumulation in the system and further cause the air conditioning performance to be low.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of air conditioning technology, and particularly relates to an air conditioning system and a control method thereof. BACKGROUND

[0002] The circulating amount of refrigerant in an air conditioning system has a great influence on the performance and energy efficiency of the air conditioning system. If the circulating amount of refrigerant is too small, the performance of the air conditioning system will be reduced, and the optimal effect cannot be achieved. If the circulating amount of refrigerant is too high, the performance of the air conditioning system will be reduced, and the cost will be increased, and the risk of liquid carrying operation of the compressor will be caused. Therefore, it is very important for the air conditioning system to match the appropriate amount of refrigerant for efficient operation.

[0003] In the matching work of the amount of refrigerant in the daily air conditioning system, the refrigerant is increased or reduced manually through a fluorine injection nozzle. This method is time-consuming and laborious. SUMMARY

[0004] Therefore, the present application provides an air conditioning system and a control method thereof, which can solve the technical problems that the air conditioning system in the prior art cannot change the amount of refrigerant in the system in real time, and the circulating amount of refrigerant is too small to reduce the performance of the system, or the circulating amount of refrigerant is too much to increase the cost, reduce the performance of the system, and have the risk of liquid carrying operation of the compressor.

[0005] In order to solve the above problems, the present application provides an air conditioning system, which comprises an evaporator, a condenser, a throttling element, and a compressor, wherein the throttling element is connected between the outlet of the condenser and the inlet of the evaporator, the inlet of the condenser and the outlet of the evaporator are connected with the compressor, the air conditioning system further comprises a first liquid storage tank, a first pipeline, a second pipeline, and a cooling branch capable of being controllably cut off, the first pipeline is controllably cut off in communication with the top of the first liquid storage tank, so as to be capable of introducing the refrigerant with a higher temperature in the air conditioning system into the first liquid storage tank, the bottom of the first liquid storage tank is in communication with the outlet of the condenser through the second pipeline, and the cooling branch has a heat exchange structure, and the refrigerant with a lower temperature in the air conditioning system flowing in the cooling branch is capable of cooling the refrigerant in the first liquid storage tank at the heat exchange structure.

[0006] In some embodiments, one end of the cooling branch is in communication with the inlet of the evaporator, and the other end of the cooling branch is in communication with the outlet of the evaporator.

[0007] In some embodiments, a first electromagnetic on-off valve and / or a first capillary tube are connected in series on the cooling branch; and / or, a second electromagnetic on-off valve and / or a second capillary tube are connected in series on the first pipeline.

[0008] In some embodiments, a second liquid storage tank is further arranged between the throttling element and the outlet of the condenser, and a fluorine pump is arranged in communication with the outlet of the second liquid storage tank; the air conditioning system further comprises a third pipeline and a fourth pipeline, wherein one end of the third pipeline is in communication with the inlet of the fluorine pump, the other end of the third pipeline is in communication with the outlet of the fluorine pump, the outlet of the fluorine pump is in communication with the inlet of the throttling element, a first one-way valve is arranged in series on the third pipeline, and the one-way communication direction of the first one-way valve is from the inlet of the fluorine pump to the inlet of the throttling element; the fourth pipeline is connected between the suction port and the discharge port of the compressor, and a second one-way valve is arranged in series on the fourth pipeline, and the one-way communication direction of the second one-way valve is from the suction port of the compressor to the discharge port of the compressor.

[0009] In some embodiments, the air conditioning system further comprises an oil separator arranged between the discharge port of the compressor and the inlet of the condenser, and the inlet of the first pipeline is connected between the outlet of the oil separator and the inlet of the condenser; the oil outlet pipe of the oil separator is in communication with the outlet pipe section of the cooling branch via a third capillary tube.

[0010] In some embodiments, a liquid level sensor is arranged in the first liquid storage tank to detect the real-time liquid level of the refrigerant in the first liquid storage tank; and / or a temperature sensor is arranged in the first liquid storage tank to detect the real-time temperature of the refrigerant in the first liquid storage tank.

[0011] The application further provides a control method of the air conditioning system, comprising the following steps:

[0012] obtaining the operating condition of the air conditioning system, and obtaining the optimal refrigerant filling amount m1 in the system cycle corresponding to the operating condition according to the operating condition;

[0013] calculating the target storage amount m2 of the refrigerant in the first liquid storage tank, m2=m0-m1, and m0 is the total filling amount of the refrigerant in the air conditioning system;

[0014] controlling the on-off of the first electromagnetic on-off valve or the second electromagnetic on-off valve to make the real-time refrigerant storage amount m in the first liquid storage tank be m2, and controlling the first electromagnetic on-off valve and the second electromagnetic on-off valve to be in the off state when the real-time refrigerant storage amount m is m2.

[0015] In some embodiments, when m

[0016] In some embodiments, when m>m2, the second electromagnetic on-off valve is controlled to be in an on state, and the first electromagnetic on-off valve is controlled to be in an off state.

[0017] In some embodiments, the real-time refrigerant storage amount m is obtained by:

[0018] The real-time temperature and real-time liquid level h of the liquid refrigerant in the first liquid storage tank are obtained, and the saturated pressure and the liquid refrigerant density p corresponding to the real-time temperature are obtained according to the refrigerant parameters pre-stored in the controller.

[0019] The real-time refrigerant storage amount m is obtained according to the formula m=ρSh, where S is the cross-sectional area of the storage space of the first liquid storage tank.

[0020] The air conditioning system and the control method thereof provided by the present application have the following beneficial effects:

[0021] The higher-temperature refrigerant is introduced into the first liquid storage tank through the first pipeline, so as to heat the refrigerant in the tank and increase the temperature and pressure of the refrigerant in the tank. The refrigerant in the tank enters the air conditioning system through the second pipeline to participate in circulation, so as to increase the refrigerant circulation amount. The lower-temperature refrigerant is introduced into the heat exchange structure through the cooling branch, and the refrigerant in the first liquid storage tank is cooled at the heat exchange structure, so as to decrease the temperature and pressure of the refrigerant in the tank. The refrigerant in the air conditioning system enters the first liquid storage tank through the second pipeline, so as to decrease the refrigerant circulation amount. That is, the technical solution of the present application changes the refrigerant circulation amount by using the cold energy or heat energy generated by the air conditioning system itself, so as to ensure that the refrigerant circulation amount in the air conditioning system matches the specific operating condition of the air conditioning system, prevent the phenomenon of low air conditioning performance caused by excessive refrigerant circulation amount and liquid accumulation in the system, reduce the use cost of the air conditioning system, and prevent the phenomenon of low air conditioning performance caused by insufficient refrigerant circulation amount. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. The drawings in the following description are only exemplary, and those skilled in the art can also obtain other embodiment drawings according to the provided drawings without creative labor.

[0023] Figure 1 is a schematic diagram of the air conditioning system of an embodiment of the present application;

[0024] Figure 2 is a schematic diagram of the air conditioning system of another embodiment of the present application.

[0025] Reference signs are:

[0026] 11 evaporator; 111 inner fan; 12 condenser; 121 outer fan; 13 throttling element; 14 compressor; 15 first liquid tank; 151 liquid level sensor; 152 temperature sensor; 16 second liquid tank; 17 fluorine pump; 18 oil separator; 181 third capillary tube;

[0027] 101 first pipeline; 1011 second electromagnetic on-off valve; 1012 second capillary tube; 102 second pipeline;

[0028] 103 cooling branch; 1031 heat exchange structure; 1032 first electromagnetic on-off valve; 1033 first capillary tube;

[0029] 104 third pipeline; 1041 first one-way valve;

[0030] 105 fourth pipeline; 1051 second one-way valve. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative work, fall within the scope of protection of the present application.

[0032] 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 position 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, therefore it 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 of the contour of each component itself.

[0033] For purposes of the description hereinafter, spatial relations terms, such as "above", "below", "upper", "lower", and the like, can be used with respect to the device or features illustrated in the drawings. However, it will be understood that no absolute spatial or positional relationships exist in the drawings. It will be further understood that the spatial terms are intended to encompass different orientations of the device or features in use or operation in addition to the orientations depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" other elements or features would then be oriented "below" the other elements or features. Thus, the exemplary term "above" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90° or at other orientations) and the spatial terms used herein interpreted accordingly.

[0034] In addition, it should be pointed out that the use of "first", "second" and the like words to define parts, only for the convenience of the corresponding parts to distinguish, 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.

[0035] The refrigerant circulation amount in the air conditioning system has a great influence on its performance and operation. Too much refrigerant circulation amount will cause the compressor load to be too large, thereby affecting its normal work, and even reaching an overload state. Overload will cause the motor current to be too large, and the air conditioner will have problems such as noise, vibration, and even burn out the compressor. At the same time, too much refrigerant will cause the refrigerant to be unable to completely evaporate in the evaporator, thereby affecting the refrigeration effect, and making the air conditioning refrigeration effect decline. Too little refrigerant circulation amount will cause the suction gas of the compressor to be too hot, thereby affecting the normal work of the compressor, and even causing a failure. At the same time, it will also cause the refrigeration capacity to be insufficient. The technical scheme of the present application can well overcome the deficiencies in the prior art.

[0036] Referring to Figure 1 and Figure 2As shown, according to the embodiment of the present application, an air conditioning system is provided, comprising an evaporator 11, a condenser 12, a throttling element 13 (for example, an electronic expansion valve) and a compressor 14, wherein the throttling element 13 is connected between the outlet of the condenser 12 and the inlet of the evaporator 11, and the compressor 14 is connected between the inlet of the condenser 12 and the outlet of the evaporator 11, thereby forming a refrigeration cycle, the air conditioning system further comprises a first liquid accumulator 15, a first pipeline 101, a second pipeline 102 and a cooling branch 103 capable of controllable on-off communication, the first pipeline 101 is in controllable cut-off communication with the top of the first liquid accumulator 15, so as to be capable of introducing the refrigerant of higher temperature in the air conditioning system into the first liquid accumulator 15, the bottom of the first liquid accumulator 15 is in communication with the outlet of the condenser 12 through the second pipeline 102 (generally, the port of the second pipeline 102 should be below the liquid level of the liquid refrigerant in the first liquid accumulator 15 during operation), the cooling branch 103 has a heat exchange structure 1031 (for example, a heat exchange pipe and the like), the refrigerant of lower temperature in the air conditioning system flowing in the cooling branch 103 is capable of cooling the refrigerant in the first liquid accumulator 15 at the heat exchange structure 1031, it can be understood that the aforementioned higher temperature refers to the temperature of the refrigerant introduced into the first liquid accumulator 15 being higher than the temperature of the refrigerant in the first liquid accumulator 15, and the lower temperature refers to the temperature of the refrigerant introduced into the heat exchange structure 1031 being lower than the temperature of the refrigerant in the first liquid accumulator 15.

[0037] In the technical solution, the refrigerant of higher temperature is introduced into the first liquid accumulator 15 through the first pipeline 101, so as to heat the refrigerant in the accumulator and increase the temperature and pressure of the refrigerant in the accumulator, and the refrigerant in the accumulator enters the air conditioning system to participate in the circulation through the second pipeline 102, thereby achieving the purpose of increasing the circulation amount of the refrigerant, the refrigerant of lower temperature is introduced into the heat exchange structure 1031 through the cooling branch 103 and cools the refrigerant in the first liquid accumulator 15 at the heat exchange structure 1031, so as to decrease the temperature and pressure of the refrigerant in the accumulator, and the refrigerant in the air conditioning system enters the first liquid accumulator 15 through the second pipeline 102, thereby achieving the purpose of reducing the circulation amount of the refrigerant, that is, the technical solution of the present application utilizes the cold or heat generated by the air conditioning system itself to change the circulation amount of the refrigerant, so as to ensure that the circulation amount of the refrigerant in the air conditioning system matches the specific operating condition of the air conditioning system, prevent the phenomenon of low air conditioning performance caused by excessive circulation amount of the refrigerant, reduce the use cost of the air conditioning system, and prevent the phenomenon of low air conditioning performance caused by insufficient circulation amount of the refrigerant.

[0038] As described above, due to the technical scheme of the present application, the refrigerant circulation amount can be kept at a reasonable level matching the current working condition, so that the air conditioning system of the present application can not have too much refrigerant circulation amount, thus avoiding the problems of excessive compressor load and reduced refrigeration effect caused by too much refrigerant circulation amount. In addition, the air conditioning system of the present application can not have too little refrigerant circulation amount, thus avoiding the problems of overheated compressor suction, insufficient system refrigeration capacity and the like.

[0039] In a specific embodiment, one end of the cooling branch 103 is in communication with the inlet of the evaporator 11, and the other end is in communication with the outlet of the evaporator 11. In a specific operation process, when the cooling branch 103 is controlled to be turned on, the low-temperature refrigerant at the inlet of the evaporator 11 will be guided into the heat exchange structure 1031 and warmed up by heat exchange with the refrigerant in the first liquid storage tank 15, and then flow back to the suction port of the compressor 14. The system design is reasonable and simple, and does not need to be externally configured with a corresponding cooling source, thus reducing the use cost of the air conditioning system.

[0040] In some embodiments, the cooling branch 103 is serially connected with a first electromagnetic on-off valve 1032 and / or a first capillary tube 1033. The on-off control of the first electromagnetic on-off valve 1032 can realize the on-off control of the cooling branch 103. Specifically, when it is needed to migrate and store the excessive refrigerant in the system circulation into the first liquid storage tank 15, the first electromagnetic on-off valve 1032 can be controlled to be turned on.

[0041] In some embodiments, the first pipeline 101 is serially connected with a second electromagnetic on-off valve 1011 and / or a second capillary tube 1012. The on-off control of the second electromagnetic on-off valve 1011 can realize the on-off control of the first pipeline 101. Specifically, when it is needed to increase the refrigerant into the system circulation, the second electromagnetic on-off valve 1011 can be controlled to be turned on.

[0042] In some embodiments, a second liquid storage tank 16 is further arranged between the throttling element 13 and the outlet of the condenser 12, and a fluorine pump 17 is arranged in communication with the liquid inlet of the fluorine pump 17 and the liquid outlet of the second liquid storage tank 16. The air conditioning system further comprises a third pipeline 104 and a fourth pipeline 105. One end of the third pipeline 104 is in communication with the liquid inlet of the fluorine pump 17, the other end is in communication with the liquid outlet of the fluorine pump 17, and the liquid outlet of the fluorine pump 17 is in communication with the liquid inlet of the throttling element 13. A first one-way valve 1041 is arranged in series on the third pipeline 104. The one-way valve 1041 is in communication from the liquid inlet side of the fluorine pump 17 to the liquid inlet side of the throttling element 13. It can be understood that when the fluorine pump 17 is running, the first one-way valve 1041 will be closed under the action of the reverse pressure difference to stop the circulation of the refrigerant in the third pipeline 104. The fourth pipeline 105 is connected between the suction port and the discharge port of the compressor 14, and a second one-way valve 1051 is arranged in series on the fourth pipeline 105. The one-way valve 1051 is in communication from the suction port side of the compressor 14 to the discharge port side of the compressor 14. When the compressor 14 is running, the second one-way valve 1051 will be closed under the action of the reverse pressure difference to stop the circulation of the refrigerant in the fourth pipeline 105.

[0043] In the technical solution, the air conditioning system is objectively a fluorine pump compression refrigeration system, which has a compression refrigeration mode and a fluorine pump refrigeration mode. In the case of a relatively reduced external environment in winter, the fluorine pump refrigeration mode can be used to cool and dissipate heat on the indoor side (e.g. a machine room), which is energy-saving and environmentally friendly. In other cases, the compression refrigeration mode can be used.

[0044] In some embodiments, the air conditioning system further comprises an oil separator 18 arranged between the discharge port of the compressor 14 and the inlet of the condenser 12, and the inlet of the first pipeline 101 is connected between the gas outlet of the oil separator 18 and the inlet of the condenser 12. The oil outlet pipe of the oil separator 18 is in communication with the outlet pipe section of the cooling branch 103 via a third capillary tube 181. In the technical solution, the oil separator 18 is arranged to separate the lubricating oil in the gas flow discharged by the compressor 14 and return it to the compressor 14, thereby ensuring sufficient lubrication of the components in the compressor 14, preventing the lubricating oil from being trapped in the heat exchanger in the system circulation, reducing the heat exchange efficiency, and reducing the heat exchange effect.

[0045] In some embodiments, the first liquid storage tank 15 is provided with a liquid level sensor 151 for detecting the real-time liquid level of the refrigerant in the first liquid storage tank 15, and / or the first liquid storage tank 15 is provided with a temperature sensor 152 for detecting the real-time temperature of the refrigerant in the first liquid storage tank 15.

[0046] According to the embodiment of the present application, a control method of the air conditioning system is also provided, comprising the following steps:

[0047] An operating condition of the air conditioning system is obtained, and an optimal refrigerant charging amount m1 (i.e. the circulating amount of refrigerant in the system) corresponding to the operating condition is obtained according to the operating condition. Specifically, the optimal refrigerant charging amount corresponding to the operating condition can be obtained by monitoring the operating parameters of the air conditioning system, including the operating frequency of the compressor, the high-pressure value, the low-pressure value, the exhaust gas superheat, the suction gas superheat, the oil temperature, and the opening degree of the expansion valve, and the optimal refrigerant charging amount corresponding to each operating condition is pre-stored in the corresponding controller.

[0048] The target refrigerant storage amount m2 in the first liquid storage tank 15 is calculated, m2 = m0-m1, and m0 is the total refrigerant charging amount in the air conditioning system.

[0049] The on-off of the first electromagnetic on-off valve 1032 or the second electromagnetic on-off valve 1011 is controlled so that the real-time refrigerant storage amount m in the first liquid storage tank 15 is m2, and the first electromagnetic on-off valve 1032 and the second electromagnetic on-off valve 1011 are both in the off state when the real-time refrigerant storage amount m is m2.

[0050] Specifically, when m < m2, the first electromagnetic on-off valve 1032 is in the on state and the second electromagnetic on-off valve 1011 is in the off state; when m > m2, the second electromagnetic on-off valve 1011 is in the on state and the first electromagnetic on-off valve 1032 is in the off state. It can be understood that when m = m2, the first electromagnetic on-off valve 1032 and the second electromagnetic on-off valve 1011 are both in the off state, and there is no need to increase or decrease the circulating amount of refrigerant.

[0051] In some embodiments, the real-time refrigerant storage amount m is obtained by the following method:

[0052] The real-time temperature and the real-time liquid level h of the liquid refrigerant in the first liquid storage tank 15 are obtained, and the saturated pressure and the liquid refrigerant density p corresponding to the real-time temperature are obtained according to the pre-stored refrigerant parameters in the controller.

[0053] The real-time refrigerant storage amount m is obtained according to the formula m = pSh, wherein S is the cross-sectional area of the storage space of the first liquid storage tank 15, and all the physical parameters are in international units. In a specific embodiment, the first liquid storage tank 15 is a cylinder with equal diameters, i.e. the cross-sectional areas S are equal, which can further simplify the obtaining of m.

[0054] The following will be described in combination with Figure 1The technical solutions of the present application are further described as follows:

[0055] 1) When the air conditioning system needs to increase the circulating amount of refrigerant

[0056] When the air conditioning system needs to increase the circulating amount of refrigerant, the flow direction of the refrigerant should be from the first liquid tank 15 to the system (i.e., system circulation). At this time, the pressure in the first liquid tank 15 should be greater than the pressure after throttling of the system, i.e., the second electromagnetic on-off valve 1011 should be opened to allow a portion of the exhaust gas to enter the first liquid tank 15 through the first pipeline 101, thereby increasing the pressure in the first liquid tank 15. At this time, the refrigerant in the tank will enter the air conditioning system circulation through the second pipeline 102 under the pressure of the exhaust gas. When the mass of the refrigerant (liquid refrigerant mass) in the first liquid tank 15 reaches m2, the second electromagnetic on-off valve 1011 is closed. During this process, the first electromagnetic on-off valve 1032 is in a cut-off state.

[0057] 2) When the air conditioning system needs to reduce the circulating amount of refrigerant

[0058] When the air conditioning system needs to reduce the circulating amount of refrigerant, the flow direction of the refrigerant should be from the system (i.e., system circulation) to the first liquid tank 15. At this time, the pressure in the first liquid tank 15 should be less than the pressure after throttling of the system, i.e., the first electromagnetic on-off valve 1032 should be opened to allow a portion of the throttled refrigerant to enter the first liquid tank 15 through the cooling branch 103, thereby performing heat exchange using the heat exchange structure 1031. At this time, the liquid refrigerant in the tank increases in density and decreases in volume and pressure after cooling, and the refrigerant in the air conditioning system can enter the first liquid tank 15 through the second pipeline 102. When the mass of the refrigerant (liquid refrigerant mass) in the first liquid tank 15 reaches m2, the first electromagnetic on-off valve 1032 is closed. During this process, the second electromagnetic on-off valve 1011 is in a cut-off state.

[0059] It is easy for those skilled in the art to understand that the advantageous technical features of each of the above-mentioned modes can be freely combined and superimposed without conflict.

[0060] The above description is only the preferred embodiments of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application. The above description is only the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and modifications without departing from the technical principles of the present application, and these improvements and modifications should be considered as within the protection scope of the present application.

Claims

1. An air conditioning system comprising an evaporator (11), a condenser (12), a throttling element (13) and a compressor (14), wherein the throttling element (13) is connected between the outlet of the condenser (12) and the inlet of the evaporator (11), and the compressor (14) is connected between the inlet of the condenser (12) and the outlet of the evaporator (11), characterized in that, The air conditioning system further comprises a first liquid storage tank (15), a first pipeline (101), a second pipeline (102) and a cooling branch (103) capable of being controllably cut off, the first pipeline (101) is controllably cut off with the top of the first liquid storage tank (15) to be capable of introducing the refrigerant with a higher temperature in the air conditioning system into the first liquid storage tank (15), the bottom of the first liquid storage tank (15) is communicated with the outlet of the condenser (12) through the second pipeline (102), the cooling branch (103) has a heat exchange structure (1031), the refrigerant with a lower temperature in the air conditioning system flowing in the cooling branch (103) is capable of cooling the refrigerant in the first liquid storage tank (15) at the heat exchange structure (1031), the inlet of the first pipeline (101) is connected between the exhaust port of the compressor (14) and the inlet of the condenser (12), one end of the cooling branch (103) is communicated with the inlet of the evaporator (11) and the other end is communicated with the outlet of the evaporator (11).

2. The air conditioning system of claim 1, wherein, The cooling branch (103) is serially connected with a first electromagnetic on-off valve (1032) and / or a first capillary tube (1033); and / or, the first pipeline (101) is serially connected with a second electromagnetic on-off valve (1011) and / or a second capillary tube (1012).

3. The air conditioning system of any one of claims 1-2, wherein, The air conditioning system further comprises a second liquid storage tank (16) and a fluorine pump (17) between the throttling element (13) and the outlet of the condenser (12), the liquid inlet of the fluorine pump (17) is communicated with the liquid outlet of the second liquid storage tank (16), the air conditioning system further comprises a third pipeline (104) and a fourth pipeline (105), wherein one end of the third pipeline (104) is communicated with the liquid inlet of the fluorine pump (17) and the other end is communicated with the liquid outlet of the fluorine pump (17), the liquid outlet of the fluorine pump (17) is communicated with the liquid inlet of the throttling element (13), the third pipeline (104) is serially connected with a first one-way valve (1041), the one-way valve (1041) is unidirectionally conducted from the liquid inlet side of the fluorine pump (17) to the liquid inlet side of the throttling element (13), the fourth pipeline (105) is connected between the suction port and the exhaust port of the compressor (14), the fourth pipeline (105) is serially connected with a second one-way valve (1051), the second one-way valve (1051) is unidirectionally conducted from the suction port side of the compressor (14) to the exhaust port side of the compressor (14).

4. The air conditioning system of claim 3, wherein, The air conditioning system further comprises an oil separator (18) between the exhaust port of the compressor (14) and the inlet of the condenser (12), the inlet of the first pipeline (101) is connected between the gas outlet of the oil separator (18) and the inlet of the condenser (12), the oil outlet pipe of the oil separator (18) is communicated with the outlet pipe section of the cooling branch (103) through a third capillary tube (181).

5. The air conditioning system of claim 1, wherein, The first liquid storage tank (15) is provided with a liquid level sensor (151) for detecting the real-time liquid level of the refrigerant in the first liquid storage tank (15); and / or, the first liquid storage tank (15) is provided with a temperature sensor (152) for detecting the real-time temperature of the refrigerant in the first liquid storage tank (15).

6. The control method of the air conditioning system according to claim 4, characterized by, The method comprises the following steps: obtaining the operating condition of the air conditioning system, and obtaining the optimal refrigerant charging amount m1 in the system cycle corresponding to the operating condition according to the operating condition; calculating the target refrigerant storage amount m2 in the first liquid storage tank (15), m2=m0-m1, m0 being the total refrigerant charging amount in the air conditioning system; controlling the on-off of the first electromagnetic on-off valve (1032) or the second electromagnetic on-off valve (1011) to make the real-time refrigerant storage amount m in the first liquid storage tank (15) be m2, and controlling the first electromagnetic on-off valve (1032) and the second electromagnetic on-off valve (1011) to be in the cut-off state when the real-time refrigerant storage amount m is m2.

7. The control method of the air conditioning system according to claim 6, characterized by, When m 8. The control method of the air conditioning system according to claim 6, characterized by, When m 9.The control method of an air conditioning system according to claim 6, characterized in that, The real-time refrigerant storage amount m is obtained by the following method: obtaining the real-time temperature and the real-time liquid level h of the liquid refrigerant in the first liquid storage tank (15), and obtaining the saturated pressure and the liquid refrigerant density ρ corresponding to the real-time temperature according to the refrigerant parameters pre-stored in the controller; obtaining the real-time refrigerant storage amount m according to the formula m=ρSh, wherein S is the cross-sectional area of the storage space of the first liquid storage tank (15).

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