Gas-liquid separator, Computer storage medium, Air conditioning system and control method thereof

Abstract

The application discloses a gas-liquid separator, a computer storage medium, an air conditioning system and a control method thereof. The gas-liquid separator comprises a tank body, a separation cavity is formed in the tank body, a spiral rib is arranged on the inner wall of the tank body, and a spiral flow channel is limited by the spiral rib; and a refrigerant inlet pipe, an outlet gas pipe and an outlet liquid pipe are connected to the tank body, the refrigerant inlet pipe, the outlet gas pipe and the outlet liquid pipe are all communicated with the separation cavity, the outlet liquid pipe is connected to the lower end of the tank body, and the refrigerant inlet pipe is used for inputting refrigerant into the spiral flow channel. The technical scheme of the application aims to optimize the structure of the gas-liquid separator, improve the gas-liquid separation efficiency of the gas-liquid separator, and thus guarantee the working performance of the compressor and prolong the service life of the compressor.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of gas-liquid separation, in particular to a gas-liquid separator, a computer storage medium, an air conditioning system and a control method thereof. BACKGROUND

[0002] In the existing air conditioning system, a gas-liquid separator is usually arranged between the outlet of the indoor heat exchanger and the return gas port of the compressor, and the gas outlet of the gas-liquid separator is connected with the return gas port of the compressor. As its name implies, the gas-liquid separator is used to separate the gaseous refrigerant and the liquid refrigerant, so as to avoid the liquid refrigerant entering the compressor and damaging the compressor. However, the gas-liquid separation efficiency of the existing gas-liquid separator is low, which leads to incomplete gas-liquid separation, so that the liquid refrigerant enters the compressor and causes liquid hammer or noise problem, which affects the working performance and service life of the compressor. SUMMARY

[0003] The main purpose of the present application is to provide a gas-liquid separator, which aims to optimize the structure of the gas-liquid separator, so as to improve the gas-liquid separation efficiency, thereby ensuring the working performance of the compressor and prolonging the service life of the compressor.

[0004] To achieve the above purpose, the gas-liquid separator provided by the present application comprises:

[0005] a tank body, a separation cavity is formed in the tank body, a spiral rib is arranged on the inner wall of the tank body, and the spiral rib limits a spiral flow channel; and

[0006] a refrigerant inlet pipe, an outlet pipe and a liquid outlet pipe connected to the tank body, the refrigerant inlet pipe, the outlet pipe and the liquid outlet pipe are all connected to the separation cavity, wherein the liquid outlet pipe is connected to the lower end of the tank body, and the refrigerant inlet pipe is used to input refrigerant into the spiral flow channel.

[0007] Optionally, the refrigerant inlet pipe is connected to the spiral flow channel.

[0008] Optionally, at the connection between the refrigerant inlet pipe and the spiral flow channel, the inner wall of the refrigerant inlet pipe is tangent to the inner wall of the tank body.

[0009] Optionally, the refrigerant flow rate of the outlet of the refrigerant inlet pipe is S, the distance from the outlet of the refrigerant inlet pipe to the bottom of the tank body is L, and the ratio of S to L is 0.25 g / (mm·s) to 0.6 g / (mm·s).

[0010] Optionally, the range of L is 100 mm to 400 mm.

[0011] Optionally, the refrigerant inlet pipe has a bent pipe section arranged outside the tank body.

[0012] Optionally, the bent pipe section is a spiral pipe section.

[0013] Optionally, the tank body comprises a tank main body and a transition section connected to the bottom of the tank main body, the liquid outlet pipe is connected to the bottom of the transition section, the transition section is arranged in a tapered structure, and the diameter of the transition section gradually decreases in the direction away from the tank main body.

[0014] Optionally, the height of the transition section accounts for 20% to 50% of the height of the tank body.

[0015] Optionally, the refrigerant inlet pipe is arranged above half the height of the tank body.

[0016] Optionally, the ratio of the pitch of the helical rib to the height of the tank main body is 0.05 to 0.3.

[0017] Optionally, the height of the helical rib is not more than 40% of the inner diameter of the tank body.

[0018] Optionally, the inner diameter of the refrigerant inlet pipe is smaller than the inner diameter of the gas outlet pipe or the inner diameter of the liquid outlet pipe.

[0019] Optionally, the refrigerant inlet pipe comprises a connecting pipe section connected to the tank body, and the distance between the center of the tank body and the center line of the connecting pipe section is smaller than the inner radius of the tank body.

[0020] Optionally, the refrigerant inlet pipe is connected to the side of the tank body, the gas outlet pipe is connected to the top of the tank body, and the gas outlet pipe has an extension section arranged in the tank body, and the outlet of the refrigerant inlet pipe and the inlet of the gas outlet pipe have a height difference.

[0021] Optionally, when the outlet of the refrigerant inlet pipe is arranged higher than the inlet of the gas outlet pipe, the liquid inlet direction of the refrigerant inlet pipe is arranged at an angle of 30 degrees to 90 degrees with respect to the gas outlet direction of the gas outlet pipe; when the outlet of the refrigerant inlet pipe is arranged lower than the inlet of the gas outlet pipe, the liquid inlet direction of the refrigerant inlet pipe is arranged at an angle of 90 degrees to 150 degrees with respect to the gas outlet direction of the gas outlet pipe.

[0022] The application further provides an air conditioning system comprising a compressor, a four-way valve, an indoor heat exchanger, an outdoor heat exchanger, and the aforementioned gas-liquid separator, the compressor is in communication with the indoor heat exchanger through a first pipe and in communication with the outdoor heat exchanger through a second pipe via the four-way valve, the indoor heat exchanger is in communication with the outdoor heat exchanger through a third pipe, and a throttling element is arranged on the third pipe.

[0023] The outdoor heat exchanger comprises a first outdoor heat exchange unit and a second outdoor heat exchange unit.

[0024] The gas outlet pipe of the gas-liquid separator is connected to the second pipeline, and a first electronic expansion valve is arranged on a connecting pipeline between the gas outlet pipe and the second pipeline, one inlet and outlet of the first outdoor heat exchange unit is communicated with the second pipeline, and the other inlet and outlet is communicated with the liquid outlet pipe of the gas-liquid separator, one inlet and outlet of the second outdoor heat exchange unit is communicated with the third pipeline, and the other inlet and outlet is communicated with the refrigerant inlet pipe of the gas-liquid separator.

[0025] The application further provides a control method of the air conditioning system, which is applied to the air conditioning system and comprises the following steps:

[0026] determining that the air conditioning system is started in a cooling mode, and controlling the first electronic expansion valve to be closed;

[0027] determining that the air conditioning system is started in a heating mode, and controlling the first electronic expansion valve to be opened.

[0028] Optionally, the step of determining that the air conditioning system is started in the heating mode and controlling the first electronic expansion valve to be opened comprises the following steps:

[0029] acquiring a running frequency of the compressor;

[0030] determining that the running frequency is less than or equal to a set frequency, and then controlling the first electronic expansion valve to maintain a first preset opening degree for a first preset time;

[0031] determining that the running frequency is greater than the set frequency, and then controlling the first electronic expansion valve to maintain a second preset opening degree for a second preset time;

[0032] wherein the second preset opening degree is greater than the first preset opening degree.

[0033] Optionally, the set frequency is F0, the maximum heating frequency of the compressor is F max , and the minimum heating frequency of the compressor is F min , wherein the F0=A(F max +F min ), and A is a constant.

[0034] Optionally, the step of determining that the air conditioning system is started in the heating mode and controlling the first electronic expansion valve to be opened further comprises the following steps:

[0035] intermittently detecting a suction temperature T1 of the compressor and a liquid outlet temperature T2 of the liquid outlet pipe;

[0036] controlling a temperature difference ΔT to be maintained between a first temperature difference and a second temperature difference, wherein ΔT=T2-T1, the first temperature difference is less than 0℃, and the second temperature difference is greater than 0℃.

[0037] Optionally, the step of controlling the ΔT to maintain between the first temperature difference and the second temperature difference is specifically:

[0038] Obtaining the ΔT;

[0039] Determining that the ΔT is less than a third temperature difference, and controlling the first electronic expansion valve to reduce the opening degree by a first preset size;

[0040] Determining that the ΔT is between the third temperature difference and the first temperature difference, and controlling the first electronic expansion valve to reduce the opening degree by a second preset size;

[0041] Determining that the ΔT is between the first temperature difference and the second temperature difference, and controlling the opening degree of the first electronic expansion valve to remain unchanged;

[0042] Determining that the ΔT is between the second temperature difference and a fourth temperature difference, and controlling the first electronic expansion valve to increase the opening degree by the second preset size;

[0043] Determining that the ΔT is greater than the fourth temperature difference, and controlling the first electronic expansion valve to increase the opening degree by the first preset size;

[0044] The first preset size is greater than the second preset size.

[0045] Optionally, the control method of the air conditioning system further comprises:

[0046] Determining that the air conditioning system is in an oil return mode or a defrosting mode, and controlling the first electronic expansion valve to be closed.

[0047] The application further provides a computer storage medium storing an air conditioning system control program, which, when executed by a processor, implements the steps of the air conditioning system control method.

[0048] In the technical scheme, the refrigerant inlet pipe inputs gas-liquid two-phase refrigerant to the spiral flow channel, and the gas-liquid two-phase refrigerant flows in the spiral flow channel, so that the gas-liquid two-phase refrigerant can generate a spiral flow on the inner wall surface of the tank body. It can be understood that the density difference between the liquid refrigerant and the gaseous refrigerant is large, resulting in a large difference in centrifugal force and gravity between the two. Under the combined action of gravity and centrifugal force, the gaseous refrigerant will diffuse radially to the separation chamber and finally flow to the return gas port of the compressor from the gas outlet pipe, and the liquid refrigerant will continue to spiral downward in the spiral flow channel and finally flow out through the liquid outlet pipe. In this way, the gas-liquid separation efficiency of the gas-liquid separator of the application is improved, which is beneficial to guarantee the working performance of the compressor and prolong the service life of the compressor. BRIEF DESCRIPTION OF DRAWINGS

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0050] FIG. 1 This is a schematic diagram of the structure of an embodiment of the gas-liquid separator of the present invention;

[0051] FIG. 2 This is a cross-sectional view of an embodiment of the gas-liquid separator of the present invention;

[0052] FIG. 3 This is a cross-sectional view of another embodiment of the gas-liquid separator of the present invention;

[0053] FIG. 4 This is a cloud map showing the gaseous volume fraction distribution of the gas-liquid separator in the air conditioning system of the present invention at a flow rate of 60 g / s.

[0054] FIG. 5 This is a cloud map showing the gaseous volume fraction distribution of the gas-liquid separator in the air conditioning system of the present invention at a flow rate of 120 g / s.

[0055] FIG. 6 This is a graph showing the relationship between the liquid outlet dryness and gas outlet pressure drop of the gas-liquid separator and the installation height L of the refrigerant inlet pipe in an embodiment of the air conditioning system of the present invention, when the flow rate is 60 g / s and the inlet dryness is 0.5.

[0056] FIG. 7 This is a graph showing the relationship between the liquid outlet dryness and gas outlet pressure drop of the gas-liquid separator and the installation height L of the refrigerant inlet pipe in an embodiment of the air conditioning system of the present invention, when the flow rate is 120 g / s and the inlet dryness is 0.5.

[0057] FIG. 8 This is a schematic diagram of the system structure of another embodiment of the air conditioning system of the present invention in heating mode;

[0058] FIG. 9 for FIG. 8 A magnified view of the outdoor heat exchanger side;

[0059] FIG. 10 This is a schematic diagram of the system structure in cooling mode of another embodiment of the air conditioning system of the present invention;

[0060] FIG. 11 for FIG. 10 A magnified view of the outdoor heat exchanger side;

[0061] FIG. 12The flow chart of the control method of the air conditioning system.

[0062] Explanation of reference numerals:

[0063] Reference Numeral Name Reference Numeral Name 100 Can body 200 Refrigerant inlet pipe 101 Separation chamber 300 Gas outlet pipe 102 Helical rib 400 Liquid outlet pipe 103 Helical flow passage 110 Can main body 120 Transition section 61 First pipe 10 Compressor 62 Second pipe 20 Four-way valve 63 Third pipe 30 Indoor heat exchanger 71 First electronic expansion valve 40 Outdoor heat exchanger 72 Second electronic expansion valve 41 First outdoor heat exchange unit 81 First temperature sensor 42 Second outdoor heat exchange unit 82 Second temperature sensor 50 Gas-liquid separator

[0064] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0065] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0066] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0067] In addition, if the embodiments of the present application involve descriptions of “first”, “second”, etc., the descriptions of “first”, “second”, etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first” and “second” can explicitly or implicitly include at least one of the features. In addition, the meaning of “and / or” appearing throughout the text is that it includes three parallel schemes, for example, “A and / or B” includes A scheme, or B scheme, or A and B schemes. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope of the present application.

[0068] The present application provides a gas-liquid separator.

[0069] In an embodiment of the present application, as shown in the drawings, the gas-liquid separator comprises:

[0070] A tank body 100, a separation cavity 101 is formed in the tank body 100, a spiral rib 102 is arranged on the inner wall of the tank body 100, and a spiral flow channel 103 is limited by the spiral rib 102; and

[0071] A refrigerant inlet pipe 200, an outlet gas pipe 300 and an outlet liquid pipe 400 are connected to the tank body 100 and communicate with the separation cavity 101, wherein the outlet liquid pipe 400 is connected to the lower end of the tank body 100, and the refrigerant inlet pipe 200 is used to input refrigerant into the spiral flow channel 103.

[0072] It can be understood that the refrigerant in the refrigerant inlet pipe is gas-liquid two-phase refrigerant. In the prior art, the gas-liquid two-phase refrigerant entering the gas-liquid separator is separated into gaseous refrigerant and liquid refrigerant by the sedimentation of liquid refrigerant under the action of gravity. However, the conventional method has a very low efficiency, and some liquid refrigerant that has not had time to sink downward is often entrained in the gaseous refrigerant flowing to the outlet gas pipe, resulting in unstable suction of the compressor, causing phenomena such as surge and whirl, causing abnormal vibration and noise of the entire machine, and even causing abnormal vibration of the pipeline, pipe breakage, and a sharp increase in noise. When the liquid refrigerant enters the compressor, it can also cause liquid hammer to the compressor, causing damage to the compressor. In summary, the efficiency of the existing gas-liquid separator is too low, which can easily lead to incomplete separation of gaseous refrigerant and liquid refrigerant, and greatly affect the working performance and service life of the compressor.

[0073] In the present application, the refrigerant inlet pipe 200 inputs gas-liquid two-phase refrigerant into the spiral flow channel 103, and the gas-liquid two-phase refrigerant flows in the spiral flow channel 103, so that the gas-liquid two-phase refrigerant can generate a spiral flow on the inner wall surface of the tank body 100. It can be understood that the density difference between the liquid refrigerant and the gaseous refrigerant is large, resulting in a large difference in centrifugal force and gravity between the two. Under the combined action of gravity and centrifugal force, the gaseous refrigerant will diffuse radially to the separation cavity 101 and eventually flow to the return gas port of the compressor from the outlet gas pipe 300, and the liquid refrigerant will continue to spiral downward in the spiral flow channel 103 and eventually flow out through the outlet liquid pipe 400. In this way, the gas-liquid separation efficiency of the gas-liquid separator of the present application is improved, which is beneficial to ensure the working performance of the compressor and prolong the service life of the compressor.

[0074] Further, in the present embodiment, the refrigerant inlet pipe 200 is connected to the spiral flow channel 103, that is, the outlet of the refrigerant inlet pipe 200 is located in the spiral flow channel 103, and the gas-liquid two-phase refrigerant flowing out of the refrigerant inlet pipe 200 can enter the spiral flow channel 103 to generate a spiral flow in the spiral flow channel 103. Of course, in other embodiments, the outlet of the refrigerant inlet pipe can also face the spiral flow channel, so that the gas-liquid two-phase refrigerant can also be input into the spiral flow channel.

[0075] Further, in the present embodiment, the inner wall of the refrigerant inlet pipe 200 is tangent to the inner wall of the tank body 100 at the connection between the refrigerant inlet pipe 200 and the spiral flow channel 103, so that the outlet of the refrigerant inlet pipe 200 and the spiral flow channel 103 are smoothly connected, reducing the loss of flow rate of the gas-liquid two-phase refrigerant at the connection between the refrigerant inlet pipe 200 and the spiral flow channel 103. In addition, the refrigerant inlet pipe 200 is arranged to be tangent to the liquid inlet, which is more conducive to the generation of the gas-liquid two-phase refrigerant.

[0076] Further, in the present embodiment, the refrigerant inlet pipe 200 has a bent pipe section arranged outside the tank body 100. The gas-liquid two-phase refrigerant enters the tank body 100 through the bent pipe section, so that the gas-liquid two-phase refrigerant can be turbulent in the bent pipe section, and the liquid droplet particles can collide and aggregate to form large particles. In this way, the density difference between the gaseous refrigerant and the liquid refrigerant can be further expanded, which is conducive to the separation of the gaseous refrigerant and the liquid refrigerant, and can further improve the gas-liquid separation efficiency.

[0077] Further, in the present embodiment, the bent pipe section is a spiral pipe section, which can further enhance the turbulent effect of the gas-liquid two-phase refrigerant in the refrigerant inlet pipe 200, thereby further improving the gas-liquid separation efficiency.

[0078] Further, in the present embodiment, the tank body 100 includes a tank main body 110 and a transition section 120 connected to the bottom of the tank main body 110, and the liquid outlet pipe 400 is connected to the bottom of the transition section 120. The transition section 120 is arranged in a conical structure, and the diameter of the transition section 120 gradually decreases in the direction away from the tank main body 110. In the present embodiment, the transition section 120 is conical, and without loss of generality, the diameter of the bottom of the transition section 120 is equal to the diameter of the liquid outlet pipe 400. It can be understood that the conical surface of the transition section 120 is conducive to the accumulation of liquid refrigerant, and facilitates the flow of liquid refrigerant out of the liquid outlet pipe 400.

[0079] In some embodiments, the height of the transition section 120 accounts for 20% to 50% of the height of the tank body 100. The transition section 120 of the present embodiment can also be used to store liquid refrigerant, and the transition section 120 arranged in this way can have a certain liquid storage space. It should be noted that the lower end of the liquid-separation gas-permeable cylinder should have a certain gap with the conical surface of the transition section 120, so as to ensure that the liquid refrigerant on the outer surface of the liquid-separation gas-permeable cylinder can flow into the liquid outlet pipe 400.

[0080] In some embodiments, the refrigerant inlet pipe 200 is arranged above half the height of the tank body 100. It should be noted that not only the outlet of the refrigerant inlet pipe 200 is above half the height of the tank body 100, but the whole refrigerant inlet pipe 200 is above half the height of the tank body 100, so as to ensure that the outlet of the refrigerant inlet pipe 200 is far enough from the bottom of the tank body 100, and the spiral flow channel 103 has sufficient length for the gas-liquid two-phase refrigerant flowing out of the outlet of the refrigerant inlet pipe 200 to generate spiral flow, which is beneficial to guarantee the gas-liquid separation efficiency of the gas-liquid separator.

[0081] In some embodiments, the ratio of the pitch of the spiral rib 102 to the height of the tank body 110 is 0.05 to 0.3. When the ratio of the pitch of the spiral rib 102 to the height of the tank body 110 is within this range, the spiral flow channel 103 can have sufficient length for the gas-liquid two-phase refrigerant to generate spiral flow, which is beneficial to guarantee the gas-liquid separation efficiency of the gas-liquid separator.

[0082] In some embodiments, the height of the spiral rib 102 is not more than 40% of the inner diameter of the tank body 100. It can be understood that the higher the height of the spiral rib 102, the larger the flow area of the spiral flow channel 103, and the greater the flow of the gas-liquid two-phase refrigerant; but the space of the separation chamber 101 will be smaller, and the gas pressure in the separation chamber 101 will rise faster with the diffusion of the gaseous refrigerant, and when the gas pressure in the separation chamber 101 is too high, it will affect the separation of the gaseous refrigerant. Therefore, the height of the spiral rib 102 should not be too high, and it is appropriate to be not more than 40% of the inner diameter of the tank body 100.

[0083] In some embodiments, the inner diameter of the refrigerant inlet pipe 200 is smaller than the inner diameter of the gas outlet pipe 300 or the inner diameter of the liquid outlet pipe 400. In the prior art, the refrigerant inlet pipe, the gas outlet pipe and the liquid outlet pipe generally use the same specification of pipe material, that is, the inner diameters of the refrigerant inlet pipe, the gas outlet pipe and the liquid outlet pipe are consistent. In this embodiment, the inner diameter of the refrigerant inlet pipe 200 is smaller than the inner diameter of the gas outlet pipe 300 or the inner diameter of the liquid outlet pipe 400, so as to improve the turbulent flow effect of the gas-liquid two-phase refrigerant in the refrigerant inlet pipe 200, thereby further improving the gas-liquid separation efficiency of the gas-liquid separator.

[0084] In some embodiments, the refrigerant inlet pipe 200 includes a connecting pipe section connected to the tank body 100, and the distance between the center of the tank body 100 and the center line of the connecting pipe section is smaller than the inner radius of the tank body 100. It can be understood that the end of the connecting pipe section is the outlet of the refrigerant inlet pipe 200. In this way, it can be ensured that the end of the connecting pipe section has sufficient flow area connected to the refrigerant flow channel, thereby reducing the local loss at the outlet of the refrigerant inlet pipe 200.

[0085] In some embodiments, the refrigerant inlet pipe 200 is connected to the side of the tank body 100, the outlet pipe 300 is connected to the top of the tank body 100, and the outlet pipe 300 has an extended section inside the tank body 100, and the outlet of the refrigerant inlet pipe 200 is higher than the inlet of the outlet pipe 300, so that the gaseous two-phase refrigerant has enough time to separate the gaseous refrigerant from the liquid refrigerant after flowing out of the outlet of the refrigerant inlet pipe 200, so as to ensure that the liquid refrigerant does not flow out of the outlet pipe 300.

[0086] Further, when the outlet of the refrigerant inlet pipe 200 is higher than the inlet of the outlet pipe 300, the liquid inlet direction of the refrigerant inlet pipe 200 is arranged at an angle of 30 to 90 degrees with the gas outlet direction of the outlet pipe 300; when the outlet of the refrigerant inlet pipe 200 is lower than the inlet of the outlet pipe 300, the liquid inlet direction of the refrigerant inlet pipe 200 is arranged at an angle of 90 to 150 degrees with the gas outlet direction of the outlet pipe 300. It can be understood that the gas outlet direction is vertically upward, and when the liquid inlet direction is arranged at an angle of 30 to 90 degrees with the gas outlet direction, it means that the connecting pipe section is arranged inclined upward; when the liquid inlet direction is arranged at an angle of 90 to 150 degrees with the gas outlet direction, it means that the connecting pipe section is arranged inclined downward. In this way, the inlet of the outlet pipe 300 can be avoided in the liquid inlet direction of the refrigerant inlet pipe 200, so as to avoid the gaseous two-phase refrigerant directly splashing into the inlet of the outlet pipe 300.

[0087] In some embodiments, the refrigerant flow rate of the outlet of the refrigerant inlet pipe 200 is S, the distance from the outlet of the refrigerant inlet pipe 200 to the bottom of the tank body 100 is L, and the ratio of S to L is 0.25 g / (mm·s) to 0.6 g / (mm·s). It should be noted that the refrigerant flow rate S is the mass flow rate, that is, the mass flow. Without loss of generality, taking the case where the liquid inlet direction of the refrigerant inlet pipe 200 is at an angle of 90 degrees with the gas outlet direction of the outlet pipe 300 as an example, at this time, the value of L is the setting height of the refrigerant inlet pipe 200. It can be understood that the faster the refrigerant flow rate S, the shorter the flow time of the refrigerant in the spiral flow channel 103, which will be not conducive to the separation of gaseous refrigerant and liquid refrigerant. At this time, the setting height L of the refrigerant inlet pipe 200 can be appropriately increased to prolong the length of the spiral flow channel 103, thereby prolonging the flow time of the refrigerant in the spiral flow channel 103. Therefore, when the ratio between the refrigerant flow rate S and the setting height L of the refrigerant inlet pipe 200 is 0.25 g / (mm·s) to 0.6 g / (mm·s), the refrigerant can flow in the spiral flow channel 103 for a sufficient time to ensure that the gaseous refrigerant can be separated from the liquid refrigerant.

[0088] In some embodiments, the distance L from the refrigerant inlet pipe 200 to the bottom of the tank body 100 is 100-400 mm, and when the value of L is within this range, the gas-liquid separation effect of the gas-liquid separator of the present application can be guaranteed.

[0089] The present application also provides an air conditioning system comprising the gas-liquid separator, the specific structure of which is described in the above embodiments. Since the air conditioning system of the present application adopts all the technical solutions of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described here again.

[0090] In an embodiment of the air conditioning system of the present application, the air conditioning system is a multi-connected refrigeration system, the refrigeration system adopts R410A refrigerant, the rated power is 12-18 kW, and the high load flow rate is 60-120 g / s.

[0091] Please refer to FIG. 4 and FIG. 5 , FIG. 4 is a gas volume fraction distribution cloud diagram of the gas-liquid separator when the flow rate is 60 g / s, FIG. 5 is a gas volume fraction distribution cloud diagram of the gas-liquid separator when the flow rate is 120 g / s, wherein the lower end color darker area is the liquid refrigerant accumulation area, and thus it can be known that as the mass flow rate rises, the liquid level of the transition section becomes higher, the distance between the liquid level and the inlet of the gas outlet becomes shorter, and the travel distance of the gas-liquid separation decreases, which will lead to the deterioration of the gas-liquid separation effect and the increase of the liquid outlet (i.e. the outlet of the liquid outlet pipe) dryness.

[0092] Please refer to FIG. 6 and FIG. 7 , FIG. 6 is a relationship diagram of the liquid outlet dryness and the gas outlet (i.e. the outlet of the gas outlet pipe) pressure drop with the setting height L (i.e. the length of the main pipe) of the refrigerant inlet pipe when the flow rate is 60 g / s and the inlet dryness is 0.5; FIG. 7 is a relationship diagram of the liquid outlet dryness and the gas outlet pressure drop with the setting height L of the refrigerant inlet pipe when the flow rate is 120 g / s and the inlet dryness is 0.5. It is not difficult to see that as the setting height L of the refrigerant inlet pipe increases, the liquid outlet dryness gradually decreases and the gas outlet pressure drop gradually increases, and thus it can be seen that the higher the setting height L of the refrigerant inlet pipe, the lower the liquid outlet dryness and the higher the gas outlet pressure drop, i.e. the better the gas-liquid separation effect. However, after the setting height L of the refrigerant inlet pipe reaches 220 mm, as L increases, the change trend of the liquid outlet dryness and the gas outlet pressure drop slows down, and thereafter, increasing the value of L has little effect on the improvement of the gas-liquid separation effect. Considering the cost and benefit comprehensively, the setting height L of the refrigerant inlet pipe is preferably 220 mm.

[0093] In another embodiment of the air conditioning system of the present application, as FIG. 8 to FIG. 11As shown, the air conditioning system further comprises a compressor 10, a four-way valve 20, an indoor heat exchanger 30, and an outdoor heat exchanger 40. The compressor 10 is in communication with the indoor heat exchanger 30 via the four-way valve 20 through a first pipe 61 and with the outdoor heat exchanger 40 through a second pipe 62. The indoor heat exchanger 30 is in communication with the outdoor heat exchanger 40 through a third pipe 63, and a throttling element is arranged on the third pipe 63.

[0094] The outdoor heat exchanger 40 comprises a first outdoor heat exchange unit 41 and a second outdoor heat exchange unit 42.

[0095] The gas outlet pipe 300 of the gas-liquid separator 50 is connected to the second pipe 62, and a first electronic expansion valve 71 is arranged on the connecting pipe between the gas outlet pipe 300 and the second pipe 62. One inlet and outlet of the first outdoor heat exchange unit 41 is in communication with the second pipe 62, and the other inlet and outlet is in communication with the liquid outlet pipe 400 of the gas-liquid separator 50. One inlet and outlet of the second outdoor heat exchange unit 42 is in communication with the third pipe 63, and the other inlet and outlet is in communication with the refrigerant inlet pipe 200 of the gas-liquid separator 50.

[0096] It can be understood that the outdoor heat exchanger functions as an evaporator in the heating mode and as a condenser in the cooling mode. However, in the prior art, when the outdoor heat exchanger functions as an evaporator, the dryness in the heat exchanger pipe increases with the progress of the evaporation process, resulting in the appearance of a mist flow region, which causes the evaporation heat transfer coefficient to sharply decrease. In addition, the increase in dryness increases the flow velocity of the refrigerant in the pipe, resulting in an increase in the refrigerant side pressure drop. When the outdoor heat exchanger functions as a condenser, liquid refrigerant accumulates in the heat exchanger pipe with the progress of the condensation process, which hinders the direct contact between the gaseous refrigerant and the pipe inner wall, thereby deteriorating the condensation heat transfer coefficient and increasing the refrigerant flow resistance loss in the pipe.

[0097] In the present embodiment, in order to solve the problems existing in the prior art, the outdoor heat exchanger 40 comprises the first outdoor heat exchange unit 41 and the second outdoor heat exchange unit 42 in communication, and the gas-liquid separator 50 is arranged on the flow paths of the first outdoor heat exchange unit 41 and the second outdoor heat exchange unit 42, so as to realize the refrigerant side heat transfer strengthening of the outdoor heat exchanger 40 in the evaporation and condensation modes.

[0098] In the evaporation mode, as shown in Fig. 1, the refrigerant in the compressor 10 is compressed to a high temperature and high pressure state, and then enters the four-way valve 20. The four-way valve 20 is controlled by the control system (not shown) to switch the connection direction of the refrigerant, so that the refrigerant enters the indoor heat exchanger 30 through the first pipe 61 and the indoor heat exchanger 30 through the third pipe 63. The refrigerant in the indoor heat exchanger 30 is cooled and condensed to a low temperature and low pressure state, and then enters the gas-liquid separator 50 through the third pipe 63. The gas-liquid separator 50 separates the gaseous refrigerant and the liquid refrigerant, and the gaseous refrigerant enters the first outdoor heat exchange unit 41 through the refrigerant inlet pipe 200, and the liquid refrigerant enters the second outdoor heat exchange unit 42 through the liquid outlet pipe 400. FIG. 8 and FIG. 9As shown, the refrigerant flows from the second outdoor heat exchange unit 42 to the first outdoor heat exchange unit 41. The gas-liquid two-phase refrigerant in the second outdoor heat exchange unit 42 flows into the gas-liquid separator 50 through the refrigerant inlet pipe 200. Then, the gaseous refrigerant flows to the second pipeline 62 through the gas outlet pipe 300, and the liquid refrigerant flows to the first heat exchange unit from the liquid outlet pipe 400. That is, after the refrigerant at the outlet of the second outdoor heat exchange unit 42 flows through the gas-liquid separator 50, the gaseous refrigerant is bypassed to the outlet of the second outdoor heat exchange unit 42, while the liquid refrigerant continues to flow to the inlet of the first outdoor heat exchange unit 41 and continues to evaporate inside the first outdoor heat exchange unit 41. In this way, the area of ​​the mist flow region inside the outdoor heat exchanger 40 can be reduced, thereby increasing the evaporative heat transfer coefficient inside the outdoor heat exchanger 40 and reducing the refrigerant side pressure drop.

[0099] In condensation mode, such as FIG. 10 and FIG. 11 As shown, the refrigerant flows from the first outdoor heat exchange unit 41 to the second outdoor heat exchange unit 42. The inlet and outlet of either the first or second outdoor heat exchange unit 41 are reversed compared to the evaporation mode. Specifically, the refrigerant from the outlet of the first outdoor heat exchange unit 41 flows into the gas-liquid separator 50 via the liquid outlet pipe 400, and then flows to the inlet of the second outdoor heat exchange unit 42 via the refrigerant inlet pipe 200. This prevents the accumulation of liquid refrigerant in the outdoor heat exchanger 40, increases the contact area between the gaseous refrigerant and the inner wall of the pipe, thereby enhancing condensation heat transfer and reducing refrigerant pressure drop.

[0100] Furthermore, in this embodiment, as FIG. 8 to FIG. 11 As shown, the outdoor heat exchanger 40 includes two parallel first outdoor heat exchange units 41 and two parallel second outdoor heat exchange units 42 to further enhance the refrigerant-side heat exchange of the outdoor heat exchanger 40 in both evaporation and condensation operating modes.

[0101] Furthermore, in this embodiment, as FIG. 8 to FIG. 11 As shown, the throttling element is configured as a second electronic expansion valve 72. Of course, in other embodiments, the throttling element may also be a capillary tube or a thermostatic expansion valve, or a throttling mechanism combining a capillary tube and an expansion valve.

[0102] Furthermore, in this embodiment, as FIG. 8 to FIG. 11 As shown, the second pipe 62 is equipped with a first temperature sensor 81 to monitor the suction temperature T1 of the compressor 10, and the third pipe 63 is equipped with a second temperature sensor 82 to monitor the liquid outlet temperature T2 of the liquid outlet pipe 400. This controls the suction temperature T1 and the liquid outlet temperature T2 within an appropriate range to ensure that the air conditioning system has a high energy efficiency ratio.

[0103] The present invention also proposes a control method for an air conditioning system, which is applied to the aforementioned air conditioning system.

[0104] In an embodiment of the control method of the air conditioning system, as shown in FIG. 12 the control method comprises the steps of:

[0105] S100, judging whether the air conditioning system is started in a cooling mode or a heating mode;

[0106] if the air conditioning system is started in the heating mode, performing the step of:

[0107] S200, controlling the first electronic expansion valve to open;

[0108] if the air conditioning system is started in the cooling mode, performing the step of:

[0109] S300, controlling the first electronic expansion valve to close.

[0110] In the air conditioning system, the first electronic expansion valve is arranged on the connecting pipeline between the gas outlet pipeline of the gas-liquid separator and the second pipeline, so that the opening and closing of the first electronic expansion valve can be controlled to control the connection between the gas outlet pipeline of the gas-liquid separator and the second pipeline. Specifically, in the heating mode, the first electronic expansion valve is opened, and the gas outlet pipeline of the gas-liquid separator is connected to the second pipeline to bypass the gaseous refrigerant; in the cooling mode, the first electronic expansion valve is closed, and the gas outlet pipeline of the gas-liquid separator and the second pipeline are in an open circuit state, and the refrigerant flowing into the gas-liquid separator from the liquid outlet pipeline will all flow to the second heat exchange unit through the refrigerant inlet pipeline, so that the gaseous refrigerant therein continues to condense in the second heat exchange unit.

[0111] Further, in the embodiment, the step S200 specifically comprises:

[0112] S210, obtaining the operating frequency of the compressor;

[0113] S220, determining whether the operating frequency is less than or equal to a set frequency, and if so, controlling the first electronic expansion valve to maintain a first preset opening degree for a first preset time;

[0114] S230, determining whether the operating frequency is greater than the set frequency, and if so, controlling the first electronic expansion valve to maintain a second preset opening degree for a second preset time;

[0115] wherein the second preset opening degree is greater than the first preset opening degree.

[0116] In the embodiment, the size of the thermal load of the air conditioning system is determined according to the size of the operating frequency of the compressor, so that different opening degrees of the first electronic expansion valve are maintained for different times when the first electronic expansion valve is opened, to achieve different initialization controls of the first electronic expansion valve according to different sizes of the thermal load.

[0117] The first preset time is preferably 2 minutes to 15 minutes, and particularly, the recommended value of the first preset time is 5 minutes; the first preset opening is preferably 20P to 100P, and particularly, the recommended value of the first preset opening is 50P; the second preset time is preferably 1 minute to 15 minutes, and particularly, the recommended value of the first preset time is 2 minutes; and the first preset opening is preferably 50P to 150P, and particularly, the recommended value of the first preset opening is 80P.

[0118] Further, in the embodiment, the set frequency is F0, the maximum heating frequency of the compressor is F max , and the minimum heating frequency is F min . The F0=A(F max +F min ), and A is a constant.

[0119] The constant A is preferably 0.45 to 0.75, and particularly, the recommended value of the constant A is 0.5. The set frequency F0 thus set can provide a suitable basis for controlling the opening of the first electronic expansion valve.

[0120] Further, in the embodiment, the step S200 further comprises the steps of:

[0121] S300, intermittently detecting the suction temperature T1 of the compressor and the outlet temperature T2 of the outlet pipe;

[0122] S400, controlling ΔT to be maintained between a first temperature difference and a second temperature difference; wherein ΔT=T2-T1, the first temperature difference is less than 0℃, and the second temperature difference is greater than 0℃.

[0123] In the embodiment, ΔT is obtained according to the suction temperature T1 measured by the first temperature sensor and the outlet temperature T2 measured by the second temperature sensor, and ΔT is controlled to be maintained between a first temperature difference and a second temperature difference. In this way, not only the heat exchanger efficiency can be optimized to improve the energy efficiency of the air conditioning system, but also the state of the compressor suction refrigerant can be optimized to improve the reliability of the air conditioning system. Particularly, the first temperature difference is set to -0.5℃, and the second temperature difference is set to 0.5℃, that is, when the control is -0.5<ΔT≤0.5, the air conditioning system will have the optimal energy efficiency ratio. The preferred range of the time interval between each adjacent detection of the suction temperature T1 and the outlet temperature T2 is 30s to 300s, wherein the suction temperature T1 and the outlet temperature T2 can be detected periodically or not periodically, and particularly, the recommended value of the time interval is 40s when the suction temperature T1 and the outlet temperature T2 are detected periodically.

[0124] Further, in the embodiment, the step S300 is specifically:

[0125] The step S310, acquiring ΔT;

[0126] The step S320, determining that ΔT is less than the third temperature difference value, then controlling the first electronic expansion valve to reduce the opening degree by a first preset size;

[0127] The step S330, determining that ΔT is between the third temperature difference value and the first temperature difference value, then controlling the first electronic expansion valve to reduce the opening degree by a second preset size;

[0128] The step S340, determining that ΔT is between the first temperature difference value and the second temperature difference value, then controlling the opening degree of the first electronic expansion valve to remain unchanged;

[0129] The step S350, determining that ΔT is between the second temperature difference value and a fourth temperature difference value, then controlling the first electronic expansion valve to increase the opening degree by the second preset size;

[0130] The step S360, determining that ΔT is greater than the fourth temperature difference value, then controlling the first electronic expansion valve to increase the opening degree by the first preset size;

[0131] Wherein, the first preset size is greater than the second preset size.

[0132] It can be understood that when ΔT is less than the first temperature difference value, that is, the suction temperature of the compressor is too high, and the suction temperature of the compressor is the temperature of the gaseous refrigerant of the second pipeline, at this time, the opening degree of the first electronic expansion valve needs to be reduced to reduce the flow of the gaseous refrigerant of the second pipeline to the gas-liquid separator, so as to reduce the temperature of the gaseous refrigerant of the second pipeline, so as to reduce the suction temperature of the compressor, and then make ΔT increase to between the first temperature difference value and the second temperature difference value. In order to ensure the control accuracy of the air conditioning system, according to the different size of ΔT, the opening degree of the first electronic expansion valve is reduced at different rates, the smaller ΔT is, the greater the opening degree of the first electronic expansion valve is reduced, so that ΔT can be restored to between the first temperature difference value and the second temperature difference value as soon as possible.

[0133] When ΔT is greater than the second temperature difference, i.e., the suction temperature of the compressor is too low, at this time, the opening of the first electronic expansion valve needs to be increased to increase the flow of gaseous refrigerant from the gas-liquid separator to the second pipeline, so as to increase the temperature of gaseous refrigerant in the second pipeline, thereby increasing the suction temperature of the compressor, and further reducing ΔT to between the first temperature difference and the second temperature difference. In order to ensure the control accuracy of the air conditioning system, the opening of the first electronic expansion valve is increased at different rates according to the size of ΔT. The greater ΔT is, the greater the opening of the first electronic expansion valve is increased, so that ΔT can be restored to between the first temperature difference and the second temperature difference as soon as possible.

[0134] When ΔT is between the first temperature difference and the second temperature difference, the opening of the first electronic expansion valve is maintained unchanged, so that ΔT can be maintained between the first temperature difference and the second temperature difference.

[0135] Specifically, the third temperature difference is set to -1.5℃, the fourth temperature difference is set to 1.5℃, the preferred range of the first preset size is 4P to 30P, and the recommended value of the first preset size is 8P in particular. The preferred range of the second preset size is 2P to 15P, and the recommended value of the second preset size is 4P in particular.

[0136] In some embodiments, step S320 is specifically:

[0137] S321, determining that ΔT<-1.5℃, and controlling the first electronic expansion valve to decrease the opening by 8P;

[0138] In some embodiments, step S330 is specifically:

[0139] S331, determining that -1.5≤ΔT<-0.5, and controlling the first electronic expansion valve to decrease the opening by 4P;

[0140] In some embodiments, step S340 is specifically:

[0141] S341, determining that -0.5≤ΔT≤0.5, and controlling the opening of the first electronic expansion valve to remain unchanged;

[0142] In some embodiments, step S350 is specifically:

[0143] S351, determining that 0.5<ΔT≤1.5, and controlling the first electronic expansion valve to increase the opening by 4P;

[0144] In some embodiments, step S360 is specifically:

[0145] S361, determining that ΔT>1.5, and controlling the first electronic expansion valve to increase the opening by 8P.

[0146] Of course, in other embodiments, to more accurately control the ΔT, a plurality of small intervals can be subdivided in the interval smaller than the first temperature difference, and the opening of the first electronic expansion valve is controlled to decrease by different sizes of opening corresponding to different small intervals, and a plurality of small intervals can also be subdivided in the interval larger than the second temperature difference, and the opening of the first electronic expansion valve is controlled to increase by different sizes of opening corresponding to different small intervals.

[0147] In addition, in other embodiments, all the above parameters can also be other values. In actual applications, the technician can set different values for the first preset time, the second preset time, the first preset opening, the second preset opening, the constant A, the time interval between each adjacent two times of detecting the suction temperature T1 and the liquid outlet temperature T2, the first temperature difference, the second temperature difference, the third temperature difference, the fourth temperature difference, the first preset size, the second preset size, and the like according to actual needs.

[0148] Further, in the present embodiment, the control method of the air conditioning system further comprises:

[0149] S500, determining that the air conditioning system is in an oil return mode or a defrosting mode, and controlling the first electronic expansion valve to be closed.

[0150] In the present embodiment, the air conditioning system also has an oil return mode and a defrosting mode. It can be understood that for a heat pump type air conditioning system, it will inevitably be accompanied by frosting in the heating mode, so the air conditioning system needs to be configured with a defrosting mode, and considering the long pipeline of the multi-split air conditioning system, the oil return mode is also necessary. When the air conditioning system runs for a period of time, the oil return mode must be executed to ensure that the oil in the air conditioning system returns to the outdoor unit from the pipeline. Further, when the air conditioning system is in the oil return mode and the defrosting mode, the first electronic expansion valve is set to a closed state, the gas-liquid separator at this time is equivalent to a section of pipeline, the gas outlet pipe is in a closed state, and the liquid outlet pipe and the refrigerant inlet pipe are used for the refrigerant and the lubricating oil to enter and exit the gas-liquid separator.

[0151] The present application also proposes a computer storage medium, which stores an air conditioning system control program, and the air conditioning system control program is executed by a processor to realize the steps of the air conditioning system control method described above, thus having all the beneficial effects of the above-mentioned embodiments of the air conditioning system control method, which will not be repeated here.

[0152] The above is only an optional embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made under the inventive concept of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A control method of an air conditioning system, characterized by, The air conditioning system comprises a compressor, a four-way valve, an indoor heat exchanger, an outdoor heat exchanger and a gas-liquid separator, the gas-liquid separator comprises a tank body, a refrigerant inlet pipe, an outlet gas pipe and an outlet liquid pipe connected to the tank body, a separation cavity is formed in the tank body, a helical rib is arranged on the inner wall of the tank body, the helical rib limits a helical flow channel, the refrigerant inlet pipe, the outlet gas pipe and the outlet liquid pipe are all communicated with the separation cavity, the outlet liquid pipe is connected to the lower end of the tank body, and the refrigerant inlet pipe is used for inputting refrigerant into the helical flow channel; The compressor is communicated with the indoor heat exchanger through a first pipe and with the outdoor heat exchanger through a second pipe via the four-way valve, the indoor heat exchanger is communicated with the outdoor heat exchanger through a third pipe, and a throttling element is arranged on the third pipe; The outdoor heat exchanger comprises a first outdoor heat exchange unit and a second outdoor heat exchange unit; The outlet gas pipe of the gas-liquid separator is connected to the second pipe, a first electronic expansion valve is arranged on the connecting pipe between the outlet gas pipe and the second pipe, one inlet and outlet of the first outdoor heat exchange unit is communicated with the second pipe, and the other inlet and outlet is communicated with the outlet liquid pipe of the gas-liquid separator, one inlet and outlet of the second outdoor heat exchange unit is communicated with the third pipe, and the other inlet and outlet is communicated with the refrigerant inlet pipe of the gas-liquid separator; The control method of the air conditioning system comprises the steps of: determining that the air conditioning system is started in a cooling mode and controlling the first electronic expansion valve to be closed; determining that the air conditioning system is started in a heating mode and controlling the first electronic expansion valve to be opened; The step of determining that the air conditioning system is started in the heating mode and controlling the first electronic expansion valve to be opened specifically comprises the steps of: acquiring the operating frequency of the compressor; determining that the operating frequency is less than or equal to a set frequency, and then controlling the first electronic expansion valve to maintain a first preset opening degree for a first preset time; determining that the operating frequency is greater than the set frequency, and then controlling the first electronic expansion valve to maintain a second preset opening degree for a second preset time; The second preset opening degree is greater than the first preset opening degree.

2. The control method of the air conditioning system according to claim 1, wherein The set frequency is F0, the maximum heating frequency of the compressor is F max , and the minimum heating frequency is F min . The F0=A(F max +F min ), and A is a constant.

3. The control method of the air conditioning system according to claim 1, wherein The step of determining that the air conditioning system is started in the heating mode and controlling the first electronic expansion valve to be opened is followed by the step of: intermittently detecting the suction temperature T1 of the compressor and the outlet liquid temperature T2 of the outlet liquid pipe; controlling T is maintained between a first temperature difference and a second temperature difference; wherein, T = T2 - T1, the first temperature difference is less than 0°C and the second temperature difference is greater than 0°C.

4. The control method of the air conditioning system according to claim 3, wherein The control The step of maintaining T between the first temperature difference and the second temperature difference is specifically: acquisition T; determining T is less than the third temperature difference value, the first electronic expansion valve is controlled to reduce the opening degree by a first preset size; determining T is between the third temperature difference value and the first temperature difference value, then controlling the first electronic expansion valve to reduce the opening degree by a second preset size; determining T is between the first temperature difference value and the second temperature difference value, then the opening degree of the first electronic expansion valve is maintained unchanged. determining T is between the second temperature difference value and the fourth temperature difference value, the first electronic expansion valve is controlled to increase the opening degree of the second preset size. determining T is greater than the fourth temperature difference value, the first electronic expansion valve is controlled to increase the opening degree of the first preset size; The first preset size is greater than the second preset size.

5. The control method of an air conditioning system according to any one of claims 1 to 4, characterized in that, The control method of the air conditioning system further comprises the steps of: determining that the air conditioning system is in an oil return mode or a defrosting mode, and controlling the first electronic expansion valve to be closed.

6. A computer storage medium, characterized in that The computer storage medium stores a control program of an air conditioning system, and the control program of the air conditioning system is executed by a processor to implement the steps of the control method of the air conditioning system according to any one of claims 1 to 5.

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