Refrigeration control method of air conditioning system and air conditioner

Abstract

The present application relates to the technical field of refrigeration equipment, and particularly provides a refrigeration control method of an air conditioning system and an air conditioner, aiming to solve the problem that the heat exchange capacity of an air conditioner outdoor unit in the environment deteriorates with the increase of the ambient temperature, thereby affecting the refrigeration effect. To this end, the refrigeration control method comprises: obtaining an ambient temperature Tao of the air conditioning system and an exhaust gas superheat degree; obtaining an actual supercooling degree A1 of the air conditioning system and a target supercooling degree A0 corresponding to the ambient temperature; comparing the target supercooling degree A0 with the actual supercooling degree A1; and selectively controlling the opening degree of a secondary electronic expansion valve based on the comparison result of the target supercooling degree A0 and the actual supercooling degree A1. According to different ambient temperatures, the present application sets different target supercooling degrees, compares the actual supercooling degree with the target supercooling degree, and controls the opening degree of the secondary electronic expansion valve according to the comparison result, so that the air conditioning system achieves better supercooling and the refrigeration effect is improved.

Description

Technical Field

[0001] This invention relates to the field of refrigeration equipment technology, specifically providing a refrigeration control method for an air conditioning system and an air conditioner. Background Technology

[0002] The refrigeration principle of an air conditioning unit is as follows: the compressor compresses the gaseous refrigerant into a high-temperature, high-pressure gaseous state and sends it to the condenser for cooling. After cooling, it becomes a medium-temperature, high-pressure liquid refrigerant, which then enters a dryer bottle for filtration and dehumidification. The medium-temperature liquid refrigerant is throttled and depressurized by the expansion valve, becoming a low-temperature, low-pressure gas-liquid mixture. After absorbing heat from the air, it evaporates into a gaseous state and then returns to the compressor to continue compression and refrigeration.

[0003] When an air conditioner is cooling, as the ambient temperature rises, the heat exchange capacity of the outdoor unit decreases, thus affecting the cooling effect.

[0004] Therefore, the present invention needs to provide a new cooling control method for an air conditioning system and an air conditioner to solve the above-mentioned technical problems. Summary of the Invention

[0005] The present invention aims to solve the above-mentioned technical problem, namely, to solve the problem that when existing air conditioners are used for cooling, the heat exchange capacity of the outdoor unit of the air conditioner deteriorates as the ambient temperature rises, thereby affecting the cooling effect.

[0006] To this end, in a first aspect, the present invention provides a cooling control method for an air conditioning system, the air conditioning system including an outdoor unit, an auxiliary electronic expansion valve installed in the outdoor unit, and the air conditioning system having a target subcooling degree pre-stored according to different ambient temperatures, the cooling control method comprising:

[0007] Obtain the ambient temperature (Tao) and exhaust superheat of the air conditioning system;

[0008] When the ambient temperature Tao is greater than the first preset temperature and the exhaust superheat is greater than the second preset temperature, the actual subcooling A1 of the air conditioning system and the target subcooling A0 corresponding to the ambient temperature are obtained.

[0009] Compare the target subcooling A0 with the actual subcooling A1;

[0010] Based on the comparison between the target subcooling A0 and the actual subcooling A1, the opening degree of the secondary electronic expansion valve is selectively controlled.

[0011] By adopting the above technical solution, the present invention sets different target subcooling degrees according to different external ambient temperatures, compares the actual subcooling degree with the target subcooling degree, and controls the opening degree of the auxiliary electronic expansion valve according to the comparison result, so that the air conditioning system can achieve better subcooling and thus improve the cooling effect of the air conditioning system.

[0012] In a specific implementation of the above-mentioned air conditioning system cooling control method, the step of "obtaining the ambient temperature Tao and exhaust superheat of the air conditioning system" further includes:

[0013] After the air conditioning system has been running for a first preset time, the ambient temperature Tao and exhaust superheat of the air conditioning system are then obtained.

[0014] When the above technical solution is adopted, acquiring the ambient temperature Tao and exhaust superheat after the air conditioning system has been running for a first preset time helps to ensure the stability and accuracy of the acquired data.

[0015] In a specific implementation of the cooling control method for the aforementioned air conditioning system, the step of "selectively controlling the opening degree of the auxiliary electronic expansion valve based on the comparison result between the target subcooling degree A0 and the actual subcooling degree A1" specifically includes:

[0016] If the actual subcooling A1 is greater than the target subcooling A0, the auxiliary electronic expansion valve is controlled to close until the opening of the auxiliary electronic expansion valve reaches its minimum value or the actual subcooling A1 equals the target subcooling A0; and / or

[0017] If the actual subcooling A1 is equal to the target subcooling A0, then the auxiliary electronic expansion valve is controlled to maintain its original opening; and / or

[0018] If the actual subcooling A1 is less than the target subcooling A0, the auxiliary electronic expansion valve is controlled to open until the opening degree of the auxiliary electronic expansion valve reaches the maximum opening value, or the exhaust superheat is less than or equal to the third preset temperature, or the actual subcooling A1 is equal to the target subcooling A0.

[0019] When the above technical solution is adopted, if the actual subcooling A1 is greater than the target subcooling A0, it means that the actual subcooling allows the air conditioning system to generate sufficient cooling capacity for refrigeration. In this case, in order to reduce operating costs, the auxiliary electronic expansion valve is closed to reduce the refrigerant flow, thereby reducing heat exchange. If the actual subcooling A1 is less than the target subcooling A0, it means that the actual subcooling is insufficient for the air conditioning system to generate sufficient cooling capacity for refrigeration. In this case, the auxiliary electronic expansion valve is opened to increase the refrigerant flow, thereby increasing the heat exchange and lowering the liquid temperature in the capillary tube, thus improving the refrigeration effect.

[0020] In a specific implementation of the cooling control method for the aforementioned air conditioning system, the operation of "the air conditioning system pre-stores target subcooling degrees set according to different external ambient temperatures" specifically involves:

[0021] The following relationship between the target subcooling A0 and the ambient temperature Tao is pre-stored in the air conditioning system:

[0022] Tao = A0 × k + b

[0023] Where k and b are both coefficients, with k ranging from 0.5 to 0.7 and b ranging from 14 to 17.

[0024] When the above technical solution is adopted, the target subcooling is obtained based on the external ambient temperature through the above relationship. The obtained target subcooling is compared with the actual subcooling. The opening degree of the auxiliary electronic expansion valve is controlled according to the comparison result to meet the required cooling effect.

[0025] In a specific implementation of the cooling control method of the above-mentioned air conditioning system, when the auxiliary electronic expansion valve performs the opening or closing operation, the opening degree of the auxiliary electronic expansion valve increases or decreases sequentially according to the preset pulse value, and the interval between two adjacent pulses is a first preset interval time.

[0026] When the above technical solution is adopted, the auxiliary electronic expansion valve remains unchanged for a first preset interval each time it increases or decreases by a preset pulse value, and then changes after the first preset interval. This provides sufficient time for heat exchange of the liquid (refrigerant) in the thin tube, avoiding the problem of frequent adjustments caused by mistakenly believing that the auxiliary electronic expansion valve does not meet the subcooling requirements due to insufficient heat exchange time and continuing to open the valve.

[0027] In a specific implementation of the cooling control method for the aforementioned air conditioning system, the step of "if the actual subcooling degree A1 is greater than the target subcooling degree A0, then controlling the auxiliary electronic expansion valve to perform a valve-closing operation" further includes:

[0028] If the actual subcooling A1 is greater than the target subcooling A0, and the duration is greater than the third preset time, then the auxiliary electronic expansion valve is controlled to close.

[0029] When the above technical solution is adopted, the valve closing operation of the auxiliary electronic expansion valve is controlled only after the actual subcooling A1 is greater than the target subcooling A0 and is maintained for a third preset time, so as to avoid the valve closing operation caused by the instability of the actual subcooling A1 and the target subcooling A0.

[0030] In a specific implementation of the cooling control method for the aforementioned air conditioning system, the step of "if the actual subcooling degree A1 is less than the target subcooling degree A0, then controlling the auxiliary electronic expansion valve to open" further includes:

[0031] If the actual subcooling degree A1 is less than the target subcooling degree A0, and the duration is greater than the fourth preset time, then the auxiliary electronic expansion valve is controlled to open.

[0032] When the above technical solution is adopted, the valve closing operation of the auxiliary electronic expansion valve is controlled only after the actual subcooling A1 is less than the target subcooling A0 and is maintained for a fourth preset time, so as to avoid the valve closing operation caused by the instability of the actual subcooling A1 and the target subcooling A0.

[0033] In a specific implementation of the cooling control method for the aforementioned air conditioning system, the step of "stopping when the exhaust superheat is less than or equal to the third preset temperature" further includes:

[0034] Stop when the exhaust superheat is less than or equal to the third preset temperature and the duration is greater than the fifth preset time.

[0035] In a specific embodiment of the refrigeration control method of the above-mentioned air conditioning system, the air conditioning system further includes an indoor unit, and the outdoor unit includes a compressor, a main electronic expansion valve, a thin tube, an auxiliary refrigeration pipe, and a condenser. One end of the thin tube is connected to the condenser, and the other end of the thin tube is connected to the indoor unit. The main electronic expansion valve is installed on the thin tube. One end of the auxiliary refrigeration pipe is connected to the thin tube after the main electronic expansion valve, and the other end of the auxiliary refrigeration pipe is connected to a gas-liquid separator. A secondary electronic expansion valve is installed on the auxiliary refrigeration pipe. The gas-liquid separator is connected to the compressor, and the auxiliary refrigeration pipe and the thin tube exchange heat through a heat exchanger.

[0036] In a second aspect, the present invention also provides an air conditioner, including a controller configured to perform the refrigeration control method of the air conditioning system described in any of the above technical solutions. Attached Figure Description

[0037] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0038] Figure 1 This is a flowchart of the main steps of the cooling control method for the air conditioning system provided by the present invention;

[0039] Figure 2 This is a detailed flowchart of the cooling control method for the air conditioning system provided by the present invention;

[0040] Figure 3 This is a schematic diagram of the outdoor unit of an air conditioning system.

[0041] List of reference numerals in the attached diagram:

[0042] 1. Compressor; 2. Gas-liquid separator; 3. Main electronic expansion valve; 4. Heat exchanger; 5. Temperature sensor; 6. Auxiliary electronic expansion valve; 7. Condenser; 8. Auxiliary refrigeration pipe; 9. Thin tube. Detailed Implementation

[0043] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0044] It should be noted that in the description of this invention, terms such as "upper," "lower," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the relevant devices or elements must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, ordinal numbers such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0046] When air conditioners are cooling, the heat exchange capacity of the outdoor unit decreases as the ambient temperature rises, thus affecting the cooling effect.

[0047] To solve the above-mentioned technical problems, the present invention provides an air conditioning system, which further includes an outdoor unit and an indoor unit. The outdoor unit includes a condenser 7, a heat exchanger 4, a thin tube 9, a gas-liquid separator 2, a main electronic expansion valve 3, and an auxiliary refrigeration pipe 8. One end of the thin tube 9 is connected to the condenser 7 of the outdoor unit, and the other end of the thin tube 9 is connected to the indoor unit. The refrigerant of the outdoor unit is transported to the indoor unit through the thin tube 9. The main electronic expansion valve 3 is installed on the thin tube 9. One end of the auxiliary refrigeration pipe 8 is connected to the thin tube 9 after passing through the main electronic expansion valve 3, and the other end of the auxiliary refrigeration pipe 8 is connected to the gas-liquid separator 2. The gas-liquid separator 2 is connected to the compressor 1. A secondary electronic expansion valve 6 is installed on the auxiliary refrigeration pipe 8. The auxiliary refrigeration pipe 8 diverts the liquid (refrigerant) in the thin tube 9. Part of the liquid enters the gas-liquid separator 2 through the auxiliary refrigeration pipe 8, and the other part of the liquid flows in the thin tube 9 and is transported to the indoor unit. The auxiliary refrigeration pipe 8 and the thin tube 9 exchange heat through the heat exchanger 4 to cool the thin tube 9. The heat exchanger 4 can be a plate heat exchanger 4. The temperature of the liquid in the thin tube 9 is detected by the temperature sensor 5. The temperature sensor 5 is installed on the part of the thin tube 9 after heat exchange by the heat exchanger 4. The auxiliary electronic expansion valve 6 is installed on the part of the auxiliary refrigeration pipe 8 that has not undergone heat exchange by the heat exchanger 4.

[0048] First refer to Figure 1 This invention provides a cooling control method for an air conditioning system, wherein the air conditioning system has pre-stored target subcooling values ​​set according to different external ambient temperatures, and the cooling control method includes:

[0049] S1, obtain the ambient temperature Tao and exhaust superheat of the air conditioning system;

[0050] S2, when the ambient temperature Tao is greater than the first preset temperature and the exhaust superheat is greater than the second preset temperature, obtain the actual subcooling A1 of the air conditioning system and the target subcooling A0 corresponding to the ambient temperature.

[0051] S3, compare the target subcooling A0 with the actual subcooling A1;

[0052] S4, based on the comparison between the target subcooling A0 and the actual subcooling A1, selectively control the opening of the secondary electronic expansion valve;

[0053] Wherein, the actual subcooling A1 is the difference between the saturation temperature corresponding to the high pressure and the temperature of the liquid (refrigerant) in the capillary tube;

[0054] Exhaust superheat is the difference between the compressor exhaust temperature and the corresponding saturation temperature at high pressure.

[0055] It should be noted that the order of obtaining the ambient temperature Tao and the exhaust superheat can be either simultaneous, or the ambient temperature Tao can be obtained first and then the exhaust superheat, or the exhaust superheat can be obtained first and then the ambient temperature. Without deviating from the basic principles of this invention, those skilled in the art can adjust the execution order as needed. Similarly, the order of obtaining the actual subcooling A1 and the target subcooling A0 can also be performed simultaneously, or one can be performed first and then the other.

[0056] Furthermore, it should be noted that this application does not impose specific limitations on the specific values ​​of the first and second preset temperatures. The values ​​can be flexibly designed according to usage requirements without departing from the basic principles of this invention. For example, the first preset temperature is 20°C, and the second preset temperature is also 20°C.

[0057] In one embodiment, the operation of "pre-storing target subcooling levels based on different ambient temperatures in the air conditioning system" specifically involves:

[0058] The following relationship between the target subcooling A0 and the ambient temperature Tao is pre-stored in the air conditioning system:

[0059] Tao = A0 × k + b

[0060] Where k and b are both coefficients, with k ranging from 0.5 to 0.7 and b ranging from 14 to 17.

[0061] In the above embodiments, the target subcooling is obtained based on the external ambient temperature using the above relationship. The obtained target subcooling is compared with the actual subcooling, and the opening of the secondary electronic expansion valve is controlled according to the comparison result to meet the required cooling effect.

[0062] For example, the value of k can be, but is not limited to, 0.55, 0.6, or 0.65, and the value of b can be, but is not limited to, 14.5, 15, or 16. Taking a value of k of 0.6 and a value of b of 17 as an example, the target supercooling is 5°C when the ambient temperature is 20°C, and 30°C when the ambient temperature is 35°C.

[0063] In one embodiment, step S1 of "obtaining the ambient temperature Tao and exhaust superheat of the air conditioning system" further includes:

[0064] The ambient temperature (Tao) and exhaust superheat of the air conditioning system are obtained after the air conditioning system has been running for the first preset time.

[0065] In the above embodiments, acquiring the ambient temperature Tao and exhaust superheat after the air conditioning system has been running for a first preset time helps to ensure the stability and accuracy of the acquired data.

[0066] In one embodiment, step S4, "selectively controlling the opening degree of the secondary electronic expansion valve based on the comparison result between the target subcooling degree A0 and the actual subcooling degree A1," specifically includes:

[0067] S41, if the actual subcooling A1 is greater than the target subcooling A0, then control the auxiliary electronic expansion valve to close the valve until the opening of the auxiliary electronic expansion valve reaches the minimum opening value or the actual subcooling A1 is equal to the target subcooling A0.

[0068] In the above steps, the actual subcooling A1 is greater than the target subcooling A0, which means that the liquid temperature in the thin tube is low, enabling the air conditioning system to generate enough cooling capacity for refrigeration. At this time, in order to reduce operating costs, the auxiliary electronic expansion valve is closed to reduce the refrigerant flow, thereby reducing the heat exchange between the heat exchanger and the liquid in the thin tube, while also ensuring the refrigeration effect.

[0069] S42, if the actual subcooling A1 is equal to the target subcooling A0, then control the auxiliary electronic expansion valve to maintain its original opening.

[0070] S43, if the actual subcooling A1 is less than the target subcooling A0, then control the auxiliary electronic expansion valve to open until the opening degree of the auxiliary electronic expansion valve reaches the maximum opening value, or the exhaust superheat is less than or equal to the third preset temperature, or the actual subcooling A1 is equal to the target subcooling A0. The third preset temperature is less than the second preset temperature.

[0071] It should be noted that this application does not impose specific limitations on the value of the third preset temperature. The temperature can be flexibly designed according to usage requirements without departing from the basic principles of this invention. For example, the value of the third preset temperature is 18°C.

[0072] In the above steps, if the actual subcooling A1 is less than the target subcooling A0, it means that the actual subcooling is insufficient for the air conditioning system to generate enough cooling capacity. At this time, the auxiliary electronic expansion valve is opened to increase the refrigerant flow, thereby increasing the heat exchange between the heat exchanger and the liquid in the thin tube, which lowers the temperature of the liquid in the thin tube and thus improves the cooling effect.

[0073] In one embodiment, the step of "stopping when the exhaust superheat is less than or equal to a third preset temperature" further includes:

[0074] Stop when the exhaust superheat is less than or equal to the third preset temperature and the duration is greater than the fifth preset time.

[0075] In the above embodiments, if the exhaust superheat is less than or equal to the third preset temperature, the duration needs to be determined. The opening operation of the auxiliary electronic expansion valve is stopped only when the duration is greater than the fifth preset time. This ensures good stability, avoids frequent adjustments of the auxiliary electronic expansion valve due to misjudgment, and helps to extend the service life of the auxiliary electronic expansion valve.

[0076] In one embodiment, when the auxiliary electronic expansion valve performs opening or closing operations, the opening degree of the auxiliary electronic expansion valve increases or decreases sequentially according to a preset pulse value, and the interval between two adjacent pulses is a first preset interval time.

[0077] In the above embodiment, the secondary electronic expansion valve remains unchanged for a first preset interval each time the preset pulse value is increased or decreased, and changes only after the first preset interval has elapsed. This provides sufficient time for heat exchange of the liquid (refrigerant) in the thin tube, avoiding the frequent adjustment problem caused by mistakenly believing that the secondary electronic expansion valve at this opening does not meet the subcooling requirements due to insufficient heat exchange time, and thus helping to extend the service life of the secondary electronic expansion valve.

[0078] In one embodiment, the step of "controlling the auxiliary electronic expansion valve to close if the actual subcooling A1 is greater than the target subcooling A0" further includes:

[0079] If the actual subcooling A1 is greater than the target subcooling A0, and the duration is greater than the third preset time, then the auxiliary electronic expansion valve will be controlled to close.

[0080] In the above embodiment, the valve closing operation of the auxiliary electronic expansion valve is controlled only after the actual subcooling A1 is greater than the target subcooling A0 and is maintained for a third preset time, so as to avoid the valve closing operation caused by the instability of the actual subcooling A1 and the target subcooling A0.

[0081] In one embodiment, the step of "controlling the auxiliary electronic expansion valve to open if the actual subcooling A1 is less than the target subcooling A0" further includes:

[0082] If the actual subcooling A1 is less than the target subcooling A0, and the duration is greater than the fourth preset time, then the auxiliary electronic expansion valve will be controlled to open.

[0083] In the above embodiment, the valve closing operation of the auxiliary electronic expansion valve is controlled only after the actual subcooling A1 is less than the target subcooling A0 and is maintained for a fourth preset time, so as to avoid the valve closing operation caused by the instability of the actual subcooling A1 and the target subcooling A0.

[0084] In one embodiment, the step of "obtaining the ambient temperature Tao and exhaust superheat of the air conditioning system" specifically includes:

[0085] The ambient temperature (Tao) and exhaust superheat of the air conditioning system are obtained according to the second preset interval.

[0086] In addition, it should be noted that the specific values ​​of the first preset time, the second preset time, the third preset time, the fourth preset time, the fifth preset time, the first preset interval time, and the second preset interval time are not specifically limited in this invention. They can be flexibly designed according to actual usage needs without deviating from the basic principles of this invention.

[0087] In a second aspect, the present invention also provides an air conditioner, including a controller configured to perform a cooling control method for an air conditioning system according to any of the above-described technical solutions.

[0088] In the above-described embodiments and extended embodiments, the present invention sets different target subcooling degrees according to different external ambient temperatures, compares the actual subcooling degree with the target subcooling degree, and controls the opening degree of the auxiliary electronic expansion valve according to the comparison result, so that the air conditioning system achieves better subcooling and thus improves the cooling effect of the air conditioning system.

[0089] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A cooling control method for an air conditioning system, characterized in that, The air conditioning system comprises an indoor unit and an outdoor unit, the outdoor unit is internally provided with a secondary electronic expansion valve, the outdoor unit comprises a compressor, a primary electronic expansion valve, a thin tube, an auxiliary refrigeration tube and a condenser, one end of the thin tube is communicated with the condenser, the other end of the thin tube is communicated with the indoor unit, the primary electronic expansion valve is installed on the thin tube, one end of the auxiliary refrigeration tube is communicated with the thin tube after the primary electronic expansion valve, the other end of the auxiliary refrigeration tube is communicated with a gas-liquid separator, the secondary electronic expansion valve is installed on the auxiliary refrigeration tube, the gas-liquid separator is connected with the compressor, the auxiliary refrigeration tube and the thin tube are in heat exchange through a heat exchanger, the air conditioning system is pre-stored with target supercooling degrees set according to different external environment temperatures, and the refrigeration control method comprises the following steps: Obtaining the external environment temperature Tao and the exhaust gas superheat degree of the air conditioning system; In the case that the external environment temperature Tao is greater than a first preset temperature and the exhaust gas superheat degree is greater than a second preset temperature, obtaining the actual supercooling degree A1 of the air conditioning system and the target supercooling degree A0 corresponding to the external environment temperature; Comparing the target supercooling degree A0 and the actual supercooling degree A1; Based on the comparison result of the target supercooling degree A0 and the actual supercooling degree A1, the opening degree of the secondary electronic expansion valve is selectively controlled.

2. The method of claim 1, wherein the method further comprises: The step of "obtaining the external environment temperature Tao and the exhaust gas superheat degree of the air conditioning system" further comprises: The external environment temperature Tao and the exhaust gas superheat degree of the air conditioning system are obtained after the air conditioning system runs for a first preset time.

3. The method of claim 1, wherein the method further comprises: The step of "based on the comparison result of the target supercooling degree A0 and the actual supercooling degree A1, the opening degree of the secondary electronic expansion valve is selectively controlled" specifically comprises: If the actual supercooling degree A1 is greater than the target supercooling degree A0, the secondary electronic expansion valve is controlled to perform valve closing operation until the opening degree of the secondary electronic expansion valve reaches a minimum opening degree value or the actual supercooling degree A1 is equal to the target supercooling degree A0; and / or If the actual supercooling degree A1 is equal to the target supercooling degree A0, the secondary electronic expansion valve is controlled to keep the original opening degree; and / or If the actual supercooling degree A1 is less than the target supercooling degree A0, the secondary electronic expansion valve is controlled to perform valve opening operation until the opening degree of the secondary electronic expansion valve reaches a maximum opening degree value or the exhaust gas superheat degree is less than or equal to a third preset temperature or the actual supercooling degree A1 is equal to the target supercooling degree A0.

4. The method of claim 1, wherein the method further comprises: The operation of "the air conditioning system is pre-stored with target supercooling degrees set according to different external environment temperatures" specifically comprises: The following relationship between the target supercooling degree A0 and the external environment temperature Tao is pre-stored in the air conditioning system: wherein k and b are coefficients, k has a value ranging from 0.5 to 0.7 and b has a value ranging from 14 to 17.

5. The method of claim 3, wherein the method further comprises: When the secondary electronic expansion valve performs valve opening or valve closing operation, the opening degree of the secondary electronic expansion valve is increased or decreased by a preset pulse value successively, and the interval between adjacent two times is a first preset interval time.

6. The method of claim 3, wherein the method further comprises: The step of "if the actual supercooling degree A1 is greater than the target supercooling degree A0, the secondary electronic expansion valve is controlled to perform valve closing operation" further comprises: If the actual supercooling degree A1 is greater than the target supercooling degree A0 and the duration is greater than a third preset time, the secondary electronic expansion valve is controlled to perform valve closing operation.

7. The method of claim 3, wherein the method further comprises: The step of "controlling the sub-electronic expansion valve to perform the opening operation if the actual supercooling degree Al is less than the target supercooling degree A0" further includes: The step of "controlling the sub-electronic expansion valve to perform the opening operation if the actual supercooling degree Al is less than the target supercooling degree A0" further includes:

8. The method of claim 3, wherein the method further comprises: The step of "stopping until the exhaust gas superheat degree is less than or equal to the third preset temperature" further includes: The step of "stopping until the exhaust gas superheat degree is less than or equal to the third preset temperature" further includes:

9. An air conditioner comprising a controller, characterized by The controller is configured to perform the refrigeration control method of the air conditioning system according to any one of claims 1-8.

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