Air conditioning system and control method thereof

Abstract

The invention provides an air conditioning system and a control method thereof.The air conditioning system comprises a compressor forming refrigerant circulation in the refrigerant flowing direction, an outdoor heat exchanger, a throttling element and an indoor heat exchanger, the air conditioning system further comprises a liquid storage tank, a preset amount of liquid refrigerant is preset in the liquid storage tank, and the liquid storage tank is provided with a first communicating opening; a refrigerant pipeline between the outdoor heat exchanger and an exhaust port of the compressor is a first refrigerant pipeline, the first communication port is communicated with the first refrigerant pipeline through a pressure reduction pipeline, and a first on-off valve is connected to the pressure reduction pipeline in series. The exhaust pressure of the compressor is reduced, frequent high-pressure protection shutdown of the compressor caused by too high exhaust pressure is prevented, the operation reliability of the compressor is improved, and the service life of the compressor and the service life of an air conditioning system are effectively prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of air conditioning, and in particular relates to an air conditioning system and a control method thereof. Background Art

[0002] In the compression refrigeration system of the computer room air conditioner, the low-pressure side is between the throttling component and the compressor suction, and the remaining part is the high-pressure side. Only by keeping the high- and low-pressure side pressures of the system within the specified range can the long-term reliable operation of the compressor be guaranteed. In actual engineering use, due to factors such as different connecting pipe lengths, differences in refrigerant injection volume, and changes in ambient temperature, the high- and low-pressure side pressures of the system often exceed the specified range, resulting in frequent system protection and shortened compressor life. Summary of the invention

[0003] Therefore, the present invention provides an air-conditioning system and a control method thereof, which can solve the technical problem in the prior art that the system exhaust pressure is too high due to factors such as different refrigerant pipe lengths, different refrigerant filling amounts, and changes in ambient temperature, resulting in frequent high-pressure protection of the system and shortening the service life of the compressor.

[0004] In order to solve the above problems, the present invention provides an air-conditioning system, including a compressor, an outdoor heat exchanger, a throttling element and an indoor heat exchanger that form a refrigerant circulation along the refrigerant flow direction. The air-conditioning system also includes a liquid storage tank, in which a preset amount of liquid refrigerant is pre-set. The liquid storage tank has a first connecting port, and the refrigerant pipeline between the outdoor heat exchanger and the exhaust port of the compressor is the first refrigerant pipeline. The first connecting port is connected to the first refrigerant pipeline via a pressure reducing pipeline, and a first on-off valve is connected in series to the pressure reducing pipeline.

[0005] In some embodiments, an oil separator is connected in series to the first refrigerant pipeline, and the pressure-reducing pipeline is connected to the first refrigerant pipeline between an outlet of the oil separator and the outdoor heat exchanger.

[0006] In some embodiments, the liquid storage tank also has a second connecting port, the refrigerant pipeline between the throttling element and the indoor heat exchanger is a second refrigerant pipeline, the second connecting port is connected to the second refrigerant pipeline via a boost pipeline, and a second on-off valve is connected in series to the boost pipeline.

[0007] In some embodiments, the first on-off valve and the second on-off valve are electromagnetic on-off valves.

[0008] In some embodiments, a gas-liquid separator is connected in series on the refrigerant pipeline between the indoor heat exchanger and the air intake of the compressor.

[0009] The present invention also provides a control method for the above air conditioning system, comprising the following steps:

[0010] Obtaining the real-time exhaust pressure Po of the compressor and the real-time tank pressure Ps in the liquid storage tank;

[0011] When the real-time exhaust pressure Po is greater than the high pressure limit P1 and the real-time exhaust pressure Po is greater than the real-time tank pressure Ps, the first on-off valve is controlled to be turned on so that part of the refrigerant airflow discharged from the exhaust port of the compressor is introduced into the liquid storage tank for storage.

[0012] In some implementations, when Po is not greater than P1 and / or Po is not greater than Ps, the first on-off valve is controlled to be cut off.

[0013] In some embodiments, when the liquid storage tank is connected to the second refrigerant pipeline via the boost pipeline, the control method further includes the following steps:

[0014] Obtaining the real-time suction pressure Pi of the compressor and the real-time tank pressure Ps in the liquid storage tank;

[0015] When the real-time suction pressure Pi is less than the low pressure limit value P2 and the real-time suction pressure Pi is less than the real-time tank pressure Ps, the second on-off valve is controlled to be turned on to allow part of the refrigerant in the liquid storage tank to flow into the second refrigerant pipeline.

[0016] In some implementations, when Pi is not less than P2 and / or Pi is not less than Ps, the second on-off valve is controlled to be cut off.

[0017] In some embodiments, when Ps is greater than P1 and Po is greater than P1 or when Ps is less than P2 and Pi is less than P2, the compressor is controlled to stop running.

[0018] The air conditioning system and control method thereof provided by the present invention have the following beneficial effects:

[0019] A liquid storage tank pre-installed with a certain amount of liquid refrigerant is added to the air-conditioning system. When the exhaust pressure of the compressor is too high, the high-pressure refrigerant can be guided to the liquid storage tank through the pressure-reducing pipeline for storage, thereby reducing the exhaust pressure of the compressor, preventing the compressor from frequently shutting down due to high-pressure protection due to excessive exhaust pressure, improving the operating reliability of the compressor, and effectively extending the service life of the compressor and the air-conditioning system;

[0020] By providing the aforementioned oil separator, when the first on-off valve is controlled to be turned on, the lubricating oil of the refrigerant guided into the liquid storage tank is first separated and refluxed in the oil separator, which effectively prevents the lubricating oil from being deposited in the liquid storage tank and causing the amount of lubricating oil in the compressor to be reduced, that is, it can ensure that there is enough lubricating oil in the compressor, further ensuring the operating reliability of the compressor;

[0021] When the suction pressure of the compressor is too low, the second on-off valve is controlled to be turned on, so that the refrigerant in the liquid storage tank can be partially transferred to the system circulation, thereby increasing the suction pressure of the compressor, preventing the compressor from being shut down due to low pressure protection due to the suction pressure being too low, further improving the operating reliability of the compressor, and extending the service life of the compressor and the air-conditioning system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. The drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0023] Figure 1 is a schematic diagram of the principle of an air conditioning system according to an embodiment of the present invention;

[0024] Figure 2 is a schematic diagram of the principle of an air conditioning system according to another embodiment of the present invention;

[0025] Figure 3 is a control flow diagram of a control method of an air conditioning system of the present invention;

[0026] Figure 4 is another control flow diagram of the control method of the air conditioning system of the present invention;

[0027] Figure 5 It is a schematic diagram of the functional modules of the control device of the air conditioning system of the present invention.

[0028] The accompanying drawings are marked as follows:

[0029] 1. compressor; 11. first pressure sensor; 12. second pressure sensor;

[0030] 2. Outdoor heat exchanger; 21. Outdoor fan;

[0031] 3. Throttling element;

[0032] 4. Indoor heat exchanger; 41. Indoor fan;

[0033] 5. Liquid storage tank; 51. First communication port; 52. Second communication port; 53. Third pressure sensor;

[0034] 61. Pressure reducing pipeline; 62. First on-off valve; 63. Pressure increasing pipeline; 64. Second on-off valve;

[0035] 71. Oil separator; 72. Gas-liquid separator. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0038] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90° or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0039] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0040] See also Figure 1 and Figure 5As shown, according to an embodiment of the present invention, an air-conditioning system is provided, including a compressor 1, an outdoor heat exchanger 2, a throttling element 3 and an indoor heat exchanger 4 that form a refrigerant circulation along the refrigerant flow direction. Specifically, after compression by the compressor 1, a high-temperature and high-pressure gaseous refrigerant is discharged to the outdoor heat exchanger 2 on the outdoor side, which is driven by an outdoor fan 21 corresponding to the outdoor heat exchanger, and then forms at least a partially liquid refrigerant. Then, after throttling at the throttling element 3 (generally an electronic expansion valve), the refrigerant enters the indoor heat exchanger 4 on the indoor side. After heat exchange with the refrigerant in the indoor heat exchanger 4, the indoor air driven by the indoor fan 41 corresponding to the indoor heat exchanger 4 forms a low-pressure gaseous refrigerant. The gaseous refrigerant is sucked into the air intake port of the compressor 1 for compression, thereby forming a refrigerant compression refrigeration cycle. The air-conditioning system also includes a liquid storage Tank 5, a preset amount of liquid refrigerant is pre-installed in the liquid storage tank 5, and the aforementioned preset amount is reasonably determined according to the actual situation of the air-conditioning system. The liquid storage tank 5 has a first connecting port 51, and the refrigerant pipeline between the outdoor heat exchanger 2 and the exhaust port of the compressor 1 (not labeled in the figure) is a first refrigerant pipeline (not labeled in the figure), and the first connecting port 51 is connected to the first refrigerant pipeline via a pressure reducing pipeline 61, and a first on-off valve 62 is connected in series to the pressure reducing pipeline 61. It can be understood that the aforementioned first on-off valve 62 is used to control the on-off of the pressure reducing pipeline 61, so as to achieve the control of the first on-off valve 62 to be in conduction when the exhaust pressure of the compressor 1 is too high, so that the high-pressure exhaust refrigerant can be partially guided to the liquid storage tank 5 for storage, so as to prevent the compressor 1 from being shut down due to high-pressure protection due to excessive exhaust pressure of the compressor 1.

[0041] In this technical solution, a liquid storage tank 5 pre-installed with a certain amount of liquid refrigerant is added to the air-conditioning system. When the exhaust pressure of the compressor 1 is too high, part of the high-pressure refrigerant can be guided to the liquid storage tank 5 for storage via the pressure-reducing pipeline 61, thereby reducing the exhaust pressure of the compressor 1, preventing the compressor 1 from frequently shutting down due to high-pressure protection due to excessive exhaust pressure, improving the operating reliability of the compressor 1, and effectively extending the service life of the compressor 1 and the air-conditioning system.

[0042] The aforementioned air conditioning system can specifically be Figure 1 The computer room air conditioning system shown in the figure has a compressor 1 arranged indoors. Figure 2 In the conventional air-conditioning system shown, the compressor 1 of the air-conditioning system is placed outdoors in order to reduce noise.

[0043] In a preferred embodiment, an oil separator 71 is connected in series to the first refrigerant pipeline, and the pressure reducing pipeline 61 is connected to the first refrigerant pipeline between the air outlet of the oil separator 71 and the outdoor heat exchanger 2 .

[0044] In this technical solution, by setting the aforementioned oil separator 71, when the first on-off valve 62 is controlled to be turned on, the lubricating oil of the refrigerant guided into the liquid storage tank 5 is first separated and refluxed in the oil separator 71, which effectively prevents this part of the lubricating oil from being deposited in the liquid storage tank 5 and causing a reduction in the amount of lubricating oil in the compressor 1, that is, it can ensure that there is enough lubricating oil in the compressor 1, further ensuring the operating reliability of the compressor 1.

[0045] In another preferred embodiment, the liquid storage tank 5 also has a second connecting port 52, the refrigerant pipeline between the throttling element 3 and the indoor heat exchanger 4 is a second refrigerant pipeline (not marked in the figure), and the second connecting port 52 is connected to the second refrigerant pipeline via a boosting pipeline 63, and a second on-off valve 64 is connected in series to the boosting pipeline 63.

[0046] In this technical solution, when the suction pressure of the compressor 1 is too low, the second on-off valve 64 is controlled to be turned on, so that the refrigerant in the liquid storage tank 5 can be partially transferred to the system circulation, thereby increasing the suction pressure of the compressor 1, preventing the suction pressure of the compressor 1 from being too low, causing the compressor 1 to shut down due to low pressure protection, further improving the operating reliability of the compressor 1, and increasing the service life of the compressor 1 and the air-conditioning system.

[0047] In a specific embodiment, the first on-off valve 62 and the second on-off valve 64 are electromagnetic on-off valves.

[0048] In order to prevent the compressor 1 from carrying liquid in the air intake, a gas-liquid separator 72 is connected in series on the refrigerant pipeline between the indoor heat exchanger 4 and the air intake port of the compressor 1, which can effectively separate the liquid phase component in the refrigerant flowing out of the indoor heat exchanger 4 to prevent the compressor 1 from liquid hammering.

[0049] According to an embodiment of the present invention, there is also provided a control method for the above-mentioned air conditioning system, comprising the following steps:

[0050] Obtaining the real-time exhaust pressure Po of the compressor 1 and the real-time tank pressure Ps in the liquid storage tank 5;

[0051] When the real-time exhaust pressure Po is greater than the high pressure limit P1 and the real-time exhaust pressure Po is greater than the real-time tank pressure Ps, the first on-off valve 62 is controlled to be turned on so that part of the refrigerant airflow discharged from the exhaust port of the compressor 1 is introduced into the liquid storage tank 5 for storage.

[0052] In this technical solution, when the exhaust pressure of the compressor 1 is higher than the high-pressure limit P1 and higher than the real-time tank pressure Ps, the first on-off valve 62 is controlled to be turned on so that part of the refrigerant discharged from the compressor 1 is introduced into the liquid storage tank 5 for storage, thereby reducing the exhaust pressure of the compressor 1 and effectively preventing the compressor 1 from shutting down frequently due to high-pressure protection. Therefore, the reliability of the compressor 1 can be improved and its service life can be improved.

[0053] After the first on-off valve 62 is turned on, part of the high-pressure and high-temperature gaseous refrigerant discharged from the compressor 1 is introduced into the liquid storage tank 5. The high-pressure gaseous refrigerant will be mixed with the refrigerant with lower pressure in the liquid storage tank 5 to form an equal pressure, thereby reducing the exhaust pressure. At the same time, the refrigerant pressure in the liquid storage tank 5 will also be increased. When Po is not greater than P1 and / or Po is not greater than Ps, the first on-off valve 62 should be controlled to be cut off.

[0054] When the liquid storage tank 5 is connected to the second refrigerant pipeline via the boost pipeline 63, the control method further includes the following steps:

[0055] Obtaining the real-time suction pressure Pi of the compressor 1 and the real-time tank pressure Ps in the liquid storage tank 5;

[0056] When the real-time suction pressure Pi is less than the low pressure limit value P2 and the real-time suction pressure Pi is less than the real-time tank pressure Ps, the second on-off valve 64 is controlled to be turned on to allow part of the refrigerant in the liquid storage tank 5 to flow into the second refrigerant pipeline.

[0057] In this technical solution, when the suction pressure of the compressor 1 is lower than the low-pressure limit P2 and lower than the real-time tank pressure Ps, the second on-off valve 64 is controlled to be turned on so that part of the refrigerant in the liquid storage tank 5 flows into the second refrigerant pipeline, thereby increasing the suction pressure of the compressor 1, preventing the suction pressure of the compressor 1 from being too low, causing the compressor 1 to shut down due to low-pressure protection, further improving the operating reliability of the compressor 1, and increasing the service life of the compressor 1 and the air-conditioning system.

[0058] After the second on-off valve 64 is turned on, part of the refrigerant in the liquid storage tank 5 flows out into the refrigerant cycle, and the refrigerant pressure of the liquid storage tank 5 gradually decreases, while the suction pressure of the compressor 1 is increased to a certain extent. When Pi is not less than P2 and / or Pi is not less than Ps, the second on-off valve 64 is controlled to be cut off.

[0059] When Ps is greater than P1 and Po is greater than P1 or when Ps is less than P2 and Pi is less than P2, the compressor 1 is controlled to stop running to prevent damage caused by the operation of the compressor 1 in this state.

[0060] When the exhaust pressure of the compressor 1 is not higher than the high pressure limit value P1 and the suction pressure is not higher than the low pressure limit value P2, the first on-off valve 62 and the second on-off valve 64 are both in the disconnected state.

[0061] The technical solution of the present invention is further described below in conjunction with a specific embodiment:

[0062] like Figure 1 As shown, a conventional machine room air conditioning system includes an indoor unit (corresponding to the indoor side in the figure) and an outdoor unit (corresponding to the outdoor side in the figure), the indoor unit includes an evaporator (i.e. the aforementioned indoor heat exchanger 4, the same below), an indoor fan (i.e. the aforementioned indoor fan 41, the same below), an expansion valve (i.e. the aforementioned throttling element 3, the same below), a compressor (i.e. the aforementioned compressor 1, the same below), an oil separator (i.e. the aforementioned oil separator 71, the same below), a gas-liquid separator (i.e. the aforementioned gas-liquid separator 72, the same below), a pressure sensor 1 (i.e. the second pressure sensor 12, the same below) and a pressure sensor 2 (i.e. the first pressure sensor 11, the same below). During the normal operation of the machine room air conditioning, the compressor compresses the refrigerant (i.e. the aforementioned refrigerant, the same below) into a high-temperature and high-pressure gas. The refrigerant passes through the oil separator and the connecting pipe into the outdoor unit for heat exchange cooling, becomes a high-temperature and high-pressure liquid, then passes through the connecting pipe into the expansion valve of the indoor unit to become a low-temperature and low-pressure liquid, then enters the evaporator for heat exchange and is converted into a low-temperature and low-pressure gas, and at the same time, the cold is transferred to the air through the indoor fan and the evaporator to cool the indoor environment, and finally returns to the compressor after passing through the gas-liquid separator, repeating the whole cycle to realize the air conditioning refrigeration function. On the basis of the conventional computer room air conditioning system, a liquid storage tank (that is, the aforementioned liquid storage tank 5, the same below), a solenoid valve 1 (that is, the aforementioned first on-off valve 62, the same below) and a pressure sensor 3 (that is, the third pressure sensor 53, the same below) are added, and the solenoid valve 1 control method is combined to realize the automatic stabilization system pressure function. The system and control method are applied to the control unit of the computer room air conditioner during the execution process, and the control unit is used to control the working state of the corresponding components on the air conditioner.

[0063] Specifically, Figure 3 The control method shown includes the following steps during application:

[0064] S21, start, when the compressor is in operation, the control method starts to be executed;

[0065] S22, obtaining the compressor exhaust pressure Po (that is, the aforementioned compressor real-time exhaust pressure Po, the same below), and obtaining the value of the compressor exhaust pressure Po through the pressure sensor 2;

[0066] S23, comparing Po with the high pressure limit value P1, where the high pressure limit value P1 is a preset value of the system program and is generally given by referring to the compressor operating pressure range in the compressor specification book; by comparing the compressor exhaust pressure Po with the high pressure limit value P1, it can be determined whether the current compressor exhaust pressure is within a reliable range, thereby determining whether the system high pressure needs to be adjusted;

[0067] S24, obtaining the liquid storage tank pressure Ps (i.e., the aforementioned real-time tank pressure Ps, the same below). When the compressor exhaust pressure Po is greater than the high pressure limit P1, the system needs to adjust the high pressure. At this time, the current liquid storage tank pressure Ps needs to be obtained through the pressure sensor 3 to determine whether the liquid storage tank meets the balanced pressure condition;

[0068] S25, comparing Ps with the exhaust pressure Po. By comparing the liquid storage tank pressure Ps with the compressor exhaust pressure Po, it can be determined whether the current liquid storage tank meets the balanced pressure condition and whether the solenoid valve 1 can be opened.

[0069] S26, open the solenoid valve 1; when the liquid storage tank pressure Ps is less than the compressor exhaust pressure Po, the current state of the liquid storage tank meets the balanced pressure condition, so the solenoid valve 1 is opened to adjust the system high pressure;

[0070] S27, close solenoid valve 1. When the compressor exhaust pressure Po is not greater than the high pressure limit P1, the system does not need to adjust the high pressure, so the solenoid valve 1 is closed; when the liquid storage tank pressure Ps is not less than the compressor exhaust pressure Po, the current state of the liquid storage tank does not meet the balanced pressure condition, and the solenoid valve 1 needs to be closed.

[0071] Reference Figure 5 The embodiment of the present invention provides a computer room air conditioning control device with automatic pressure stabilization, which includes: a control module 1 S41, used to collect the compressor exhaust pressure Po, the high pressure limit P1, and the liquid storage tank pressure Ps; a control module 2 S42, used to determine whether the system high pressure needs to be adjusted; a control module 3 S43, used to determine whether the current liquid storage tank meets the balanced pressure condition; a control module 4 S44, used to open or close the solenoid valve 1.

[0072] In this embodiment, the compressor exhaust pressure Po, the high pressure limit P1, and the liquid storage tank pressure Ps are first collected through the control module 1, and then the control module 2 determines whether the system high pressure needs to be adjusted, and then the control module 3 determines whether the current liquid storage tank meets the balanced pressure condition, and the control module 4 opens or closes the solenoid valve 1, thereby realizing the function of automatically balancing the system high pressure, so as to improve the operating reliability of the compressor and increase the service life of the computer room air conditioner.

[0073] See also Figure 1As shown, on the basis of the conventional computer room air conditioning system, a liquid storage tank, a solenoid valve 2 and a pressure sensor 3 are added, and the solenoid valve 2 control method is combined to realize the automatic stabilization system pressure function. During the execution process, the system and control method are applied to the control unit of the computer room air conditioner, and the control unit is used to control the working state of the corresponding components on the air conditioner.

[0074] Specifically, Figure 4 The control method shown includes the following steps during application:

[0075] S31, start, when the compressor is in operation, the control method starts to be executed;

[0076] S32, obtaining the suction pressure Pi of the compressor (that is, the real-time suction pressure Pi mentioned above, the same below), and obtaining the value of the suction pressure Pi of the compressor through the pressure sensor 1;

[0077] S33, compare Pi with the low pressure limit value P2, the low pressure limit value P2 is a preset value of the system program, which is generally given by referring to the compressor operating pressure range in the compressor specification book; by comparing the compressor suction pressure Pi with the low pressure limit value P2, it can be determined whether the current compressor suction pressure is within the reliable range, thereby determining whether the system low pressure needs to be adjusted;

[0078] S34, obtaining the liquid storage tank pressure Ps. When the compressor suction pressure Pi is less than the low pressure limit P2, the system needs to adjust the low pressure. At this time, the current liquid storage tank pressure Ps needs to be obtained through the pressure sensor 3 to determine whether the liquid storage tank meets the balanced pressure condition;

[0079] S35, comparing Ps with the suction pressure Pi. By comparing the liquid storage tank pressure Ps with the compressor suction pressure Pi, it can be determined whether the current liquid storage tank meets the balanced pressure condition, thereby determining whether the solenoid valve 2 can be opened;

[0080] S36, open the solenoid valve 2. When the pressure Ps of the liquid storage tank is greater than the suction pressure Pi of the compressor, the current state of the liquid storage tank meets the balanced pressure condition, so the solenoid valve 2 is opened to adjust the system low pressure;

[0081] S37, close solenoid valve 2. When the compressor suction pressure Pi is not less than the low pressure limit P2, the system does not need to adjust the low pressure, so the solenoid valve 2 is closed; when the liquid storage tank pressure Ps is not greater than the compressor suction pressure Pi, the current state of the liquid storage tank does not meet the balanced pressure condition, and the solenoid valve 2 needs to be closed.

[0082] It is easy for those skilled in the art to understand that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. An air conditioning system, comprising a compressor (1) for forming a refrigerant circulation along the refrigerant flow direction, an outdoor heat exchanger (2), a throttling element (3) and an indoor heat exchanger (4), characterized in that: It also includes a liquid storage tank (5), in which a preset amount of liquid refrigerant is pre-installed. The liquid storage tank (5) has a first connecting port (51). The refrigerant pipeline between the outdoor heat exchanger (2) and the exhaust port of the compressor (1) is a first refrigerant pipeline. The first connecting port (51) is connected to the first refrigerant pipeline via a pressure reducing pipeline (61), and a first on-off valve (62) is connected in series to the pressure reducing pipeline (61).

2. The air conditioning system according to claim 1, characterized in that: An oil separator (71) is connected in series to the first refrigerant pipeline, and the pressure reducing pipeline (61) is connected to the first refrigerant pipeline between the air outlet of the oil separator (71) and the outdoor heat exchanger (2).

3. The air conditioning system according to claim 1, characterized in that: The liquid storage tank (5) also has a second connecting port (52), and the refrigerant pipeline between the throttling element (3) and the indoor heat exchanger (4) is a second refrigerant pipeline. The second connecting port (52) is connected to the second refrigerant pipeline via a boost pipeline (63), and a second on-off valve (64) is connected in series to the boost pipeline (63).

4. The air conditioning system according to claim 3, characterized in that: The first on-off valve (62) and the second on-off valve (64) are electromagnetic on-off valves.

5. The air conditioning system according to claim 1, characterized in that: A gas-liquid separator (72) is connected in series to the refrigerant pipeline between the indoor heat exchanger (4) and the air intake port of the compressor (1).

6. A control method for an air conditioning system according to any one of claims 1 to 5, characterized in that: The steps include: Obtaining the real-time exhaust pressure Po of the compressor (1) and the real-time tank pressure Ps in the liquid storage tank (5); When the real-time exhaust pressure Po is greater than the high-pressure limit value P1 and the real-time exhaust pressure Po is greater than the real-time tank pressure Ps, the first on-off valve (62) is controlled to be turned on so that part of the refrigerant airflow discharged from the exhaust port of the compressor (1) is introduced into the liquid storage tank (5) for storage.

7. The control method according to claim 6, characterized in that: When Po is not greater than P1 and / or Po is not greater than Ps, the first on-off valve (62) is controlled to be cut off.

8. The control method according to claim 6, characterized in that: When the liquid storage tank (5) is connected to the second refrigerant pipeline via the boost pipeline (63), the control method further comprises the following steps: Obtaining the real-time suction pressure Pi of the compressor (1) and the real-time tank pressure Ps in the liquid storage tank (5); When the real-time suction pressure Pi is less than the low pressure limit value P2 and the real-time suction pressure Pi is less than the real-time tank pressure Ps, the second on-off valve (64) is controlled to be turned on so that part of the refrigerant in the liquid storage tank (5) flows into the second refrigerant pipeline.

9. The control method according to claim 8, characterized in that: When Pi is not less than P2 and / or Pi is not less than Ps, the second on-off valve (64) is controlled to be cut off.

10. The control method according to claim 8, characterized in that: When Ps is greater than P1 and Po is greater than P1 or when Ps is less than P2 and Pi is less than P2, the compressor (1) is controlled to stop running.

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